Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Field Procedures”

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 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Status of the Mu2e calorimeter readout electronics

The Mu2e experiment [1] at Fermilab will search for the neutrino-less coherent conversion of a muon into an electron in the field of a nucleus. Mu2e detectors comprise a straw tracker, an electromagnetic calorimeter and a veto for cosmic rays. The calorimeter employs 1348 Cesium Iodide crystals readout by silicon photomultipliers and fast front-end and digitization electronics. The front-end electronics consists of two discrete readout circuits (AMP-HV) for each crystal. These provide the amplification, shaping stage and linear regulation of the SiPM bias voltage and monitoring. The SiPM and front-end control electronics is implemented in a battery of mezzanine boards each equipped with an ARM processor that controls a group of 20 Amp-HV circuits distributing the low voltage and the high-voltage. The electronic is hosted in crates located on the external surface of calorimeter disks. The crates also host the waveform digitizer board (DIRAC) that performs digitization of the front end signals and transmit the digitized data to the Mu2e DAQ. Calorimeter electronic is hosted inside the cryostat and must sustain very high radiation and magnetic field so it was necessary to fully qualify it. The system design and quality assurance procedures will be reviewed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1992

Optimal grazing incidence optics and its application to wide-field X-ray imaging

A class of high-resolution, efficient, and wide-field grazing incidence optics is discussed. Optical designs for searching efficiently for distant X-ray clusters are developed. It is shown that a rather general procedure exists for the design of an optical mission if well-defined scientific goals can be provided. Clusters of galaxies with an angular diameter of about 5 arcsec over a field of about 1 deg are resolved so that a comprehensive deep search is possible with a payload of 1/10 the linear dimensions of AXAF. By dropping the requirement for perfect on-axis imagery, searching within a suitably general class of telescope design, and optimizing a quantity directly related to the scientific requirement, it is shown that satisfactory designs do exist. The resulting telescope is shown to be no more difficult to fabricate than existing mirrors, and it can be nested.

Burrows, Christopher J.↗
DOE OSTI2014

Conformal perturbation theory, dimensional regularization, and AdS/CFT correspondence

We study relevant deformations of conformal field theory on a cylinder using conformal perturbation theory, and in particular the one-point function of the deformation operator and the energy in a system after a quench. We do the one-point function calculation in both AdS and the conformal field theory and we show that the results match. Our calculations are done with arbitrary spacetime dimension, as well as arbitrary scaling dimension of the relevant operator. The only singularities that appear in the end calculation can be related to logarithmic singularities in dimensional regularization. We also study time-dependent setups in the field theory and we show how the response of the system can be calculated in a Hamiltonian-based approach. Here, we use this procedure to explain certain short time universal results that have been found previously.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS2010

GeoLab in NASA's Pressurized Excursion Module: First Results from the 2010 Field Trials

Before humans explore other planets, NASA must develop advanced techniques for collection, preservation and return of unique extraterrestrial samples. To help evaluate hardware requirements and operational concepts for future sample-return missions, we designed and built GeoLab our first generation lab for geological samples into NASA s Habitat Demonstration Unit in the Pressurized Excursion Module (HDU1-PEM). The center of GeoLab is a glovebox for the examination of samples in a shirt-sleeve environment. As part of a deployable habitat, GeoLab can participate in NASA s analog missions that simulate planetary exploration activities and support the testing of relevant technologies for collecting and handling geological samples. Over time, these tests will evaluate sample handling environments (field and lab), sampling tools and analytical instruments, and different scenarios involving both robotic and human procedures. The GeoLab design supports evolving tests and configurations. The glovebox is mounted on the habitat bulkhead, with three sample pass-though chambers that allow for direct sample transfer into the glovebox from the outside. The glovebox design and construction (low-particle shedding, minimally off-gassing materials) provides a clean environment to reduce sample contamination; in the future, we will integrate a positive pressure, enriched nitrogen atmosphere. The glovebox is equipped with configurable instrument ports. The 2010 test included a mass balance, a stereomicroscope with a HD camera for detailed imaging of samples, and a handheld XRF analyzer for preliminary geochemical characterization of samples. Network cameras provided context imagery and sample handling activities. We present early results from the initial field trial of GeoLab during the 2010 Desert Research and Technology Studies (D-RATS) planetary analog test near Flagstaff AZ. The 2010 D-RATS mission involved two rovers, the habitat with GeoLab, four crew members, and a team of scientists and flight controllers. The crewed rovers conducted geological traverses and collected samples on the planetary surface. Selected samples were transferred into GeoLab for detailed examination and initial analysis, providing critical data to the science team for evaluation and prioritization of samples.

Evans, Cynthia A.↗
DOE OSTI2017

Neutron Imaging of Laser Melted SS316 Test Objects with Spatially Resolved Small Angle Neutron Scattering

A novel neutron far field interferometer is explored for sub-micron porosity detection in laser sintered stainless steel alloy 316 (SS316) test objects. The results shown are images and volumes of the first quantitative neutron dark-field tomography at various autocorrelation lengths, ξ . In this preliminary work, the beam defining slits were adjusted to an uncalibrated opening of 0.5 mm horizontal and 5 cm vertical; the images are blurred along the vertical direction. In spite of the blurred attenuation images, the dark-field images reveal structural information at the micron-scale. The topics explored include: the accessible size range of defects, potentially 338 nm to 4.5 μ m, that can be imaged with the small angle scattering images; the spatial resolution of the attenuation image; the maximum sample dimensions compatible with interferometry optics and neutron attenuation; the procedure for reduction of the raw interferogram images into attenuation, differential phase contrast, and small angle scattering (dark-field) images; and the role of neutron far field interferometry in additive manufacturing to assess sub-micron porosity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

An overview of craniospinal axis fields and field matching

Many methods are implemented for craniospinal axis (CSA) radiation treatment (RT). This paper’s goal is to define correctly matched CSA RT fields. Overlap or a space between matched RT fields can create variances of dose and the possibility of negative side effects or disease recurrence, respectively. An accurate CSA RT match procedure is created with localization markers, immobilization devices, equations, feathered matches, safety gap, and portal imaging. A CS match angle is predetermined to optimize patient position before immobilization device fabrication. Various central axis (CA) placements within the brain and spine fields that effect gantry, table, and collimator rotation are described. An overview of the methods used to create CSA RT fields and matches is presented for optimal CSA RT implementation. In addition, to the author’s knowledge, this is the first time that a prone CSA RT with anesthesia has been described.

61 RADIATION PROTECTION AND DOSIMETRY↗
NASA NTRS1979

Calculation of the three-dimensional flow field in supersonic inlets at angle of attack using a bicharacteristic method with discrete shock wave fitting

An analysis is presented for calculating the flow field in supersonic mixed-compression aircraft inlets operating at angle of attack. The flow field is computed by a steady three-dimensional bicharacteristic method. The bow shock wave and the reflected internal shock wave system are computed by a three-dimensional discrete shock wave fitting procedure. Viscous and thermal diffusion may be included as source terms in the bicharacteristic method. A production type computer program capable of determining the flow field in a variety of axisymmetric mixed-compression supersonic inlets is available. The results of the present analysis agree well with those produced by the two-dimensional method of characteristics when axisymmetric flow fields are computed. For three-dimensional flow fields, the results of the present analysis agree well with experimental data except in regions of high viscous interaction and boundary layer removal. The present analysis does not compute the boundary layer, nor does it account for boundary layer bleed.

Vadyak, J.↗
NASA NTRS1993

Next generation initiation techniques

Four-dimensional data assimilation strategies can generally be classified as either current or next generation, depending upon whether they are used operationally or not. Current-generation data-assimilation techniques are those that are presently used routinely in operational-forecasting or research applications. They can be classified into the following categories: intermittent assimilation, Newtonian relaxation, and physical initialization. It should be noted that these techniques are the subject of continued research, and their improvement will parallel the development of next generation techniques described by the other speakers. Next generation assimilation techniques are those that are under development but are not yet used operationally. Most of these procedures are derived from control theory or variational methods and primarily represent continuous assimilation approaches, in which the data and model dynamics are 'fitted' to each other in an optimal way. Another 'next generation' category is the initialization of convective-scale models. Intermittent assimilation systems use an objective analysis to combine all observations within a time window that is centered on the analysis time. Continuous first-generation assimilation systems are usually based on the Newtonian-relaxation or 'nudging' techniques. Physical initialization procedures generally involve the use of standard or nonstandard data to force some physical process in the model during an assimilation period. Under the topic of next-generation assimilation techniques, variational approaches are currently being actively developed. Variational approaches seek to minimize a cost or penalty function which measures a model's fit to observations, background fields and other imposed constraints. Alternatively, the Kalman filter technique, which is also under investigation as a data assimilation procedure for numerical weather prediction, can yield acceptable initial conditions for mesoscale models. The third kind of next-generation technique involves strategies to initialize convective scale (non-hydrostatic) models.

Warner, Tom↗
DOE OSTI2013

Use of Electronic Hand-held Devices for Collection of Savannah River Site Environmental Data - 13329

Savannah River Nuclear Solutions has begun using Xplore Tablet PC's to collect data in the field for soil samples, groundwater samples, air samples and round sheets at the Savannah River Site (SRS). EPA guidelines for groundwater sampling are incorporated into the application to ensure the sample technician follows the proper protocol. The sample technician is guided through the process for sampling and round sheet data collection by a series of menus and input boxes. Field measurements and well stabilization information are entered into the tablet for uploading into Environmental Restoration Data Management System (ERDMS). The process helps to eliminate input errors and provides data integrity. A soil sample technician has the ability to collect information about location of sample, field parameter, describe the soil sample, print bottle labels, and print chain of custody for the sample that they have collected. An air sample technician has the ability to provide flow, pressure, hours of operation, print bottle labels and chain of custody for samples they collect. Round sheets are collected using the information provided in the various procedures. The data are collected and uploaded into ERDMS. The equipment used is weather proof and hardened for the field use. Global Positioning System (GPS) capabilities are integrated into the applications to provide the location where samples were collected and to help sample technicians locate wells that are not visited often. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1972

Relaxation techniques for three-dimensional transonic flow about wings.

A relaxation procedure has been developed to treat the three-dimensional, transonic small perturbation equations about finite lifting wings. A combination of two schemes is employed. For flow forward of the wing trailing edge the equations are written in terms of a velocity potential in order to minimize computer algebra and storage. For the remaining flow field the equations are written in terms of the velocity components in order to simplify the enforcement of the Kutta condition. Difference equations and relaxation procedures are described for both schemes. The computational method automatically captures the imbedded shock wave in the three-dimensional flow field. Computed results are given and compared to experiment and other inviscid methods.

Bailey, F. R.↗
DOE OSTI2016

SU-F-J-50: Study On the Magnetic Field Effect On the Exradin W1 Plastic Scintillation Detector

Purpose: To study the response of the Exradin W1 plastic scintillator detector to a 6 MV photon field in the presence of a strong magnetic field (B). Methods: An Exradin W1 scintillator detector coupled to a SuperMax two-channel electrometer, both manufactured by Standard Imaging, Inc., was first calibrated in a Co-60 beam. The Cerenkov Light Ratio (CLR) was obtained following the procedure recommended by the manufacturer. Subtracting signal in channel 2 multiplied by CLR from the signal in channel 1 should lead to a Cerenkov-free signal. The W1 scintillator was placed in a plastic phantom inside a dipole electromagnet (GMW Associates) that could produce a strong B field, and irradiated using a 6 MV beam from an Elekta Versa HD LINAC. Signals from both channels of the W1 scintillator were acquired as a function of B (0 - 1.5 T). Results: The signals from both channels increased as a function of the B field strength. At 1.5 T, channel 1 increased by 11% compared to the baseline (B=0 T), while channel 2 increased by 22%. Applying the recommended Cerenkov correction led to a 2% difference between dose measurement with and without a magnetic field. The values between B=0.3 T and B=1.5 T remained constant. Conclusion: Signals from the Exradin W1 plastic scintillation detector increased as the B field increased. This increase mainly comes from a change in the amount of Cerenkov light coupled within the optical fiber. Removing the Cerenkov component following the procedure recommended by the manufacturer showed to be an effective way to measure dose accurately in strong magnetic fields. The cause for the residual 2% difference is currently under investigation. We acknowledge research support from Elekta AB.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1987

Elemental abundance analyses with coadded DAO spectrograms. I - The field horizontal-branch stars HD-64488, 109995 and 161817

It is possible to improve the quality of elemental-abundance analyses by using higher-S/N data than has been the practice at high resolution. The procedures developed at the Dominion Astrophysical Observatory to coadd high-dispersion coude spectrograms are used with a minimum of 10 6.5-A/mm IIa-O spectrograms of each of three field hoorizontal-branch (FHB) A stars to increase the S/N of the photographic data over a considerable wavelength region. Fine analyses of the sharp-lined prototype FHB stars HD 109995 and 161817 show an internal consistency which justifies this effort. Their photospheric elemental abundances are similar to those of Population II globular cluster giants. As their photometric and spectrophotometric properties are similar to blue HB stars in such clusters, they are confirmed to be the brighter analogs of such stars. HD 64488, which is photometrically and spectrophotometrically similar to the FHB stars, is found to be metal-poor (Fe/H = -1) with much broader lines (v sin i = 147 km/s). The implications of the abundance anomalies of all three stars are discussed.

Adelman, Saul J.↗
DOE OSTI2021

Experiments and CFD simulation of mass transfer and hydrodynamics in a cylindrical bubble column

Flow visualization, Particle Image Velocimetry (PIV) and dissolved oxygen charging experiments are carried out in a small-scale cylindrical air-water bubble column at different superficial gas velocities. Void fraction profile, total gas holdup, liquid phase velocity field and volumetric mass transfer coefficient are obtained. Details of each experiment are given, with a new procedure for obtaining a 2D void fraction profile from flow visualization by image processing and time averaging which could provide useful information for CFD model validation. The experimental results are analyzed and compared with simulations where good agreement is found for both local and global flow patterns. The averaged governing equations and constitutive relations used in the simulation are discussed briefly, with emphasis on the proper comparison between simulations and experiments based on the derivation of the two-fluid model. Finally, by conducting three sets of experiments related to phase distribution, velocity field and mass transfer in the same apparatus, a validated CFD model for multiphase mass transfer is established and can be used in the future design of a multi-phase reactor.

42 ENGINEERING↗
NASA NTRS2018

Advances in Above- and In-Water Radiometry, Volume 2: Autonomous Atmospheric and Oceanic Observing Systems

This publication documents the scientific advances associated with new instrument systems and accessories built to improve above- and in-water observations of the apparent optical properties (AOPs) of optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation in the shortest time possible. The Hybridspectral Alternative for Remote Profiling of Optical Observations for NASA Satellites (HARPOONS) is presented as a case example of technologies conceived, developed, and deployed operationally in support of next-generation mission requirements. The field trials, field commissioning, and operational demonstration resulted in a technology readiness level (TRL) value of 9 for a diversity of laboratory and field instrument systems. Separate detailed presentations of the individual instruments provide the hardware designs, accompanying software for data acquisition and processing, and examples of the results achieved. For the laboratory components, calibration and characterization procedures are described along with an estimation of the sources of uncertainty, which culminates in a full uncertainty budget for the radiometers deployed to the field.

Hooker, Stanford B.↗
DOE OSTI2016

The comparison of 5-field conformal radiotherapy techniques for the treatment of prostate cancer: The best for femoral head sparing

External radiotherapy is a standard treatment procedure for localized prostate cancer. Given the relatively high long term survival treatment complications have been brought in center of attention. In this planning study, between 2012 and 2014, CT simulation data of 90 consecutive high-risk prostate cancer patients were collected. In the first phase, all were planned for whole pelvis irradiation up to 46Gy in 23 daily fractions. In the second phase, only the prostate gland was the target of radiation. Next, the subjects were divided randomly into three groups and each received a unique 5field conformal radiation plan including Plan A (Gantry angle: 0, 60, 120, 240, and 300), Plan B (Gantry angles: 0, 90, 120, 240, and 270) and Plan C (Gantry angles: 0, 60, 90, 270, and 300). The total dose was 70Gy. For each patient, the rectum, bladder, and both femoral heads were contoured as the at risk organs (OAR). From dose volume histograms, the proportional dose of PTV V100, the bladder and rectum V80 and V90 and femoral head V50 and V100 were calculated in all subjects and compared across plans. A statistically significant difference in the femoral head V50 and V100 was found between our studied 5field plans so that in Plan A (beam angles: 0, 60, 120, 240 and 300) less dose was received by both heads of femur. This study suggests that 5 field treatment planning including an anterior, two anterior oblique and two posterior oblique portals to be more proper for 3D conformal radiotherapy in order to spare femoral head with acceptable PTV coverage, and bladder and rectal doses.

61 RADIATION PROTECTION AND DOSIMETRY↗
NASA NTRS1991

The analysis of a rocket tomography measurement of the N2+3914A emission and N2 ionization rates in an auroral arc

Techniques were developed for recovering two-dimensional distributions of auroral volume emission rates from rocket photometer measurements made in a tomographic spin scan mode. These tomographic inversion procedures are based upon an algebraic reconstruction technique (ART) and utilize two different iterative relaxation techniques for solving the problems associated with noise in the observational data. One of the inversion algorithms is based upon a least squares method and the other on a maximum probability approach. The performance of the inversion algorithms, and the limitations of the rocket tomography technique, were critically assessed using various factors such as (1) statistical and non-statistical noise in the observational data, (2) rocket penetration of the auroral form, (3) background sources of emission, (4) smearing due to the photometer field of view, and (5) temporal variations in the auroral form. These tests show that the inversion procedures may be successfully applied to rocket observations made in medium intensity aurora with standard rocket photometer instruments. The inversion procedures have been used to recover two-dimensional distributions of auroral emission rates and ionization rates from an existing set of N2+3914A rocket photometer measurements which were made in a tomographic spin scan mode during the ARIES auroral campaign. The two-dimensional distributions of the 3914A volume emission rates recoverd from the inversion of the rocket data compare very well with the distributions that were inferred from ground-based measurements using triangulation-tomography techniques and the N2 ionization rates derived from the rocket tomography results are in very good agreement with the in situ particle measurements that were made during the flight. Three pre-prints describing the tomographic inversion techniques and the tomographic analysis of the ARIES rocket data are included as appendices.

Mcdade, Ian C.↗
DOE OSTI2025

Greenhouse Gas Accounting Procedures in Low Carbon Fuel Policies Overlook the Spatial Variability of Miscanthus-Derived Sustainable Aviation Fuel

Low carbon fuel policies such as the U.S. Renewable Fuel Standard (RFS), Canada Clean Fuel Regulations (CFR), and California Low Carbon Fuel Standard (LCFS) as well as the 45Z tax credit are intended to reduce greenhouse gas (GHG) emissions from transportation. Cellulosic feedstocks, optimized biorefineries, and favorable farming locations can significantly reduce biofuel carbon intensity (CI). Despite advances in field-to-fuel GHG monitoring and flexibility in resource allocation within biorefineries (e.g., governing net electricity production), rigid CI accounting procedures in current policies may limit CI responsiveness across candidate sites and processing facilities. Here, this work examines a hypothetical biomass-to-sustainable aviation fuel (SAF) pathway using miscanthus and alcohol-to-jet (i) to demonstrate how GHG accounting requirements drive estimates of biofuel CIs and (ii) to explore potential CI and financial implications of scenario-specific life cycle assessment (LCA). Results demonstrate that GHG accounting using the CFR/LCFS can reasonably account for distinct levels of net electricity production by a biorefinery, but only the CFR yields similar CI sensitivity to spatially explicit factors (feedstock CI, grid electricity CI) as scenario-specific LCA: most GHG accounting frameworks do not capture CI variation across candidate sites in the United States. Ultimately, this work demonstrates the importance of LCA methodological specifications in low carbon fuel policies and tax credits.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1983

Optimization of acoustic liners by the hybrid finite element-integral approach

An iterative solution technique for predicting the sound field radiated from a turbofan inlet is used to predict the optimum inlet acoustic liner. The analytical approach divides the sound field into two regions: the sound field within and near the inlet which is computed using the finite element method and the radiation field beyond the inlet which is calculated using an integral solution technique. A continuous solution is obtained by matching the finite element and integral solutions at the interface between the two regions. Using a trial and error scheme, this analytical procedure is used to calculate the impedance value of the duct liner which will produce a minimum sound pressure level in the far field. Several examples of straight and non-uniform ducts with and without flow are presented.

Sigman, R. K.↗