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At least 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Complete Performance Comparison Between the Optimized Image Construction Algorithm (U-MBIR) and the Existing Reconstruction Algorithm for Detecting Defects and Damage in Concrete

Reinforced concrete (RC) is a composite material subjected to mechanical, thermal, and chemical loads throughout its service life. Because of these external stressors and the susceptibility of RC structural members to shrinkage and microcracking, the material degrades throughout its life cycle. This deterioration can lead to a decrease in member capacity and, ultimately, poses a threat to the structural integrity. Thus, it is crucial that the damage caused by aging and degradation be monitored and assessed at regular intervals throughout the material’s service life. Since coring of the material is typically not feasible for in-service structural systems, non-destructive evaluation (NDE) methodologies are used to assess remaining structural capacity. NDE methods enable surface and subsurface examination without damaging or degrading the medium. Moreover, RC is a critical component of nuclear power plants; thus, its safety and reliability must be thoroughly examined throughout the life cycle of the structural system. Ultrasonic measurements have been an industry standard for both surface and subsurface inspections. To this end, Oak Ridge National Laboratory (ORNL) has researched and developed advanced image reconstruction algorithms to capture internal damage. The results and discussion presented herein summarize the current state of the ultrasonic model–based iterative reconstruction (U-MBIR) algorithm developed at ORNL. More specifically, this report presents a comparison between reconstruction images produced via a widely employed ultrasonic NDE technique—the synthetic aperture focusing technique (SAFT)—and the ORNL-developed U-MBIR algorithm. These NDE methodologies are demonstrated using ultrasonic data collected from four concrete specimens. Overall, the U-MBIR algorithm eliminates artifacts and noise that are typically present within the SAFT reconstructions, and it shows defects and anomalies more clearly than the SAFT images. In conclusion, this algorithm is suitable for identifying concrete defects, although more improvements and optimization could be done to better define internal defects.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Thermal Damage Potential of Electric Vehicles

The main objective is to assess the risk that electric vehicle (EV) battery fires pose regarding thermal damage to other vehicles involved in a crash and to compare EV and internal combustion engine vehicle (ICEV) fires. A literature review of experimental data and statistics are used to perform the assessment. The findings indicate: (1) the heat flux emitted from an EV and ICEV fire are similar due to cabin materials being the main contributor to heat flux, (2) for ICEVs involved in a crash with fuel tank leakage, the thermal damage is significantly more than from an EV fire for equivalent fire durations, (3) the thermal damage potential from ICEV pool fires is at least 5 times higher than EV fires, and (4) EV and ICEV crashes resulting in a fire is about 0.002% and 0.2%, respectively. Thus, EV battery fires have a lower risk than ICEV fires.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Recent Progress on Radiation Damage Studies at RaDIATE

Recent major accelerator facilities have been limited in beam power by production target and beam window survivability, where radiation damage to their constituent materials has been identified as the most cross-cutting challenge facing these high power target facilities. The RaDIATE collaboration, Radiation Damage In Accelerator Target Environments, was formed in 2012 to address this challenge by bringing together experts from the fields of nuclear materials and accelerator target facilities. The collaboration conducted high intensity proton beam irradiation of test specimens at the Brookhaven Linac Isotope Producer (BLIP) facility at BNL, where the specimens, including candidate materials for various beam intercepting device applications, were provided by participating accelerator facilities. Post-Irradiation Examination (PIE) of the irradiated specimens is being conducted at participating nuclear/fusion research institutions with appropriate ``hot-cell'' facilities, such as Pacific Northwest National Laboratory (PNNL).The recent collaboration work also includes efforts to provide the samples irradiated at BLIP to in-beam thermal shock test at CERN's HiRadMat facility. It will be the first examination to observe how the radiation-damaged material will behave when exposed to actual beam loading conditions. In this talk up-to-date status of these experiments, PIEs, and prospect for the works conducted by the RaDIATE collaboration are over-viewed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Reduced ribonucleotide reductase RRM2 subunit expression increases DNA damage and mitochondria dysfunction in woody breast chickens

Abstract OBJECTIVE The aim of this study was to investigate the roles of ribonucleotide reductase subunit M2 (RRM2; subunit of ribonucleotide reductase) in severe woody breast (WB) and normal breast muscles. ANIMALS 40 8-week-old male Ross-708 broiler chickens. METHODS Quantitative PCR was performed to determine gene expression, and commercial ELISA/assay kits were used to obtain several enzymatic activities. RESULTS Results showed that RRM2 activity (P= .0002) and RRM2 (P= .05) and hydroxymethylbilane synthase expression (impaired oxygen transport and metabolism,P= .002) were reduced in WB, while caveolin-3 (defected membrane integrity,P= .09), endoglin (increased fibrosis,P= .06), and secreted protein acidic rich in cysteine (metabolic dysregulation,P= .09) expression tended to increase in WB. WB tended to have increased levels of homocysteine (P= .06), aspartate aminotransferase mitochondria (P= .02), pyruvate kinase (P= .04), DNA damage (P= .06), creatine kinase (P= .05), and triglyceride (P= .002) but decreased ATPase activity (P= .01), all indicating mitochondria dysfunction and tissue damage. CLINICAL RELEVANCE In this study, differences in various enzyme activities and increased DNA damage suggest that RRM2-mediated mitochondrial abnormalities may play a role in WB myopathy.

Veterinary Sciences↗
DOE OSTI2014

Extracellular ATP acts as a damage-associated molecular pattern (DAMP) signal in plants

As sessile organisms, plants have evolved effective mechanisms to protect themselves from environmental stresses. Damaged (i.e., wounded) plants recognize a variety of endogenous molecules as danger signals, referred to as damage-associated molecular patterns (DAMPs). ATP is among the molecules that are released by cell damage, and recent evidence suggests that ATP can serve as a DAMP. Although little studied in plants, extracellular ATP is well known for its signaling roles in animals, including acting as a DAMP during the inflammatory response and wound healing. If ATP acts outside the cell, then it is reasonable to expect that it is recognized by a plasma membrane-localized receptor. Recently, DORN1, a lectin receptor kinase, was shown to recognize extracellular ATP in Arabidopsis. DORN1 is the founding member of a new purinoceptor subfamily, P2K (P2 receptor kinase), which is plant-specific. P2K1 (DORN1) is required for ATP-induced cellular responses (e.g., cytosolic Ca2+ elevation, MAPK phosphorylation, and gene expression). Genetic analysis of loss-of-function mutants and overexpression lines showed that P2K1 participates in the plant wound response, consistent with the role of ATP as a DAMP. In this review, we summarize past research on the roles and mechanisms of extracellular ATP signaling in plants, and discuss the direction of future research on extracellular ATP as a DAMP signal.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Contactless Ultrasonic Wavefield Imaging to Visualize Near-Surface Damage in Concrete Elements

We present work to detect and visualize near-surface damage in concrete using contactless ultrasonic wavefield imaging technology. A fully contactless ultrasonic scanning system that utilizes a micro-electro-mechanical systems (MEMS) ultrasonic microphone array is used to collect ultrasonic surface wave data from a concrete sample. The obtained wavefield data sets are processed with a frequency-wavenumber (f-k) domain wavefield filtering approach to extract non-propagating oscillatory fields set up by near-surface concrete cracking damage. The experimental results demonstrate that near-surface concrete damage can be detected and visualized using the proposed ultrasonic wavefield imaging approach.

Song, Homin (ORCID:0000000269141579)↗
DOE OSTI2024

A Brief Review of the Impact of Neutron Irradiation Damage in Tungsten and Its Alloys

Neutron irradiation poses a substantial challenge in the development and application of tungsten (W) and its alloys, predominantly in the framework of nuclear fusion and fission environments. Although W is well-acknowledged for its unique properties like its high melting temperature and higher resistance to sputtering, transmutation products, such as Re and Os, form and impact the alloy properties as a result of neutron irradiation. This transmutation effect accompanied by significant microstructure damage due to neutron irradiation can lead to the significant degradation of mechanical properties. This review surveys the literature focusing on the microstructural modifications post-irradiation and its impacts on the irradiation hardening. This review provides insights into the elaborative understanding on the neutron radiation damage on W and W alloys by exploring the microstructural evolution and hardness changes post-irradiation. The gaps and future opportunities for understanding neutron radiation damage in W are briefly summarized.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Abiotic and Biotic Damage of Microalgae Generate Different Volatile Organic Compounds (VOCs) for Early Diagnosis of Algal Cultures for Biofuel Production

Open microalgal ponds used in industrial biomass production are susceptible to a number of biotic and abiotic environmental stressors (e.g., grazers, pathogens, pH, temperature, etc.) resulting in pond crashes with high economic costs. Identification of signature chemicals to aid in rapid, non-invasive, and accurate identification of the stressors would facilitate targeted and effective treatment to save the algal crop from a catastrophic crash. Specifically, we were interested in identifying volatile organic compounds (VOCs) that can be used to as an early diagnostic for algal crop damage. Cultures of Microchloropsis gaditana were subjected to two forms of algal crop damage: (1) active grazing by the marine rotifer, Brachionus plicatilis, or (2) repeated freeze–thaw cycles. VOCs emitted above the headspace of these algal cultures were collected using fieldable solid phase microextraction (SPME) fibers. An untargeted analysis and identification of VOCs was conducted using gas chromatography-mass spectrometry (GC-MS). Diagnostic VOCs unique to each algal crop damage mechanism were identified. Active rotifer grazing of M. gaditana was characterized by the appearance of carotenoid degradation products, including β-cyclocitral and various alkenes. Freeze–thaw algae produced a different set of VOCs, including palmitoleic acid. Both rotifer grazing and freeze–thawed algae produced β-ionone as a VOC, possibly suggesting a common stress-induced cellular mechanism. Importantly, these identified VOCs were all absent from healthy algal cultures of M. gaditana. Early detection of biotic or abiotic environmental stressors will facilitate early diagnosis and application of targeted treatments to prevent algal pond crashes. Thus, our work further supports the use of VOCs for monitoring the health of algal ponds to ultimately enhance algal crop yields for production of biofuel.

09 BIOMASS FUELS↗
DOE OSTI2022

Ultrafast Laser Material Damage Simulation—A New Look at an Old Problem

The chirped pulse amplification technique has enabled the generation of pulses of a few femtosecond duration with peak powers multi-Tera and Peta–Watt in the near infrared. Its implementation to realize even shorter pulse duration, higher energy, and higher repetition rate laser systems relies on overcoming the limitations imposed by laser damage of critical components. In particular, the laser damage of coatings in the amplifiers and in post-compression optics have become a bottleneck. The robustness of optical coatings is typically evaluated numerically through steady-state simulations of electric field enhancement in multilayer stacks. However, this approach cannot capture crucial characteristics of femtosecond laser induced damage (LID), as it only considers the geometry of the multilayer stack and the optical properties of the materials composing the stack. This approach neglects that in the interaction of an ultrashort pulse and the materials there is plasma generation and associated material modifications. Here, we present a numerical approach to estimate the LID threshold of dielectric multilayer coatings based on strong field electronic dynamics. In this dynamic scheme, the electric field propagation, photoionization, impact ionization, and electron heating are incorporated through a finite-difference time-domain algorithm. We applied our method to simulate the LID threshold of bulk fused silica, and of multilayer dielectric mirrors and gratings. The results are then compared with experimental measurements. The salient aspects of our model, such as the implementation of the Keldysh photoionization model, the impact ionization model, the electron collision model for ‘low’-temperature, dense plasma, and the LID threshold criterion for few-cycle pulses are discussed.

36 MATERIALS SCIENCE↗
NASA NTRS1971

Metal fatigue damage - Mechanism, detection, avoidance, and repair.

Collection of theoretical and experimental studies covering basic mechanisms of fatigue in the subcreep and creep ranges, fatigue damage detection, field practices for fatigue damage repair in jet engine components, and fatigue damage avoidance and control. Individual items are abstracted in this issue.

Manson, S. S.↗
NASA NTRS1972

Hail damage to typical aircraft surfaces.

Severe structural damage can occur when aircraft collide with hailstones. Consequently, methods of predicting hail damage to airplane surfaces are needed by the aircraft designer. This paper describes an analytical method of predicting the dent depth and final deformed shape for simple structural components impacted by hailstones. The solution was accomplished by adapting the DEPROSS computer program to the problem of normal impact of hail on flat metallic sheets and spherical metallic caps. Experimental data and analytical predictions are presented for hail damage to typical aircraft surfaces along with a description of the hail gun and hail simulation technique used in the experimental study.

Hayduk, R. J.↗
NASA NTRS1971

Measurement of lattice damage caused by ion-implantation doping of semiconductors.

Discussion of two new techniques used to measure the lattice damage produced in GaAs by the implantation of 60 keV cadmium ions. In the first method, optical reflection spectra of the ion-implanted samples were measured in the wavelength range from 2000 to 4600 A. The decrease in reflectivity resulting from ion-implantation was used to determine the relative amount of lattice damage as a function of ion dose. The second technique employed the scanning electron microscope. Patterns very similar in appearance to Kikuchi electron diffraction patterns are obtained when the secondary and/or backscattered electron intensity is displayed as a function of the angle of incidence of the electron beam on a single crystal surface. The results of measurements made by both methods are compared with each other and with data obtained by the method of measuring lattice damage by Rutherford scattering of 1 MeV helium ions.

Hunsperger, R. G.↗
NASA NTRS1973

The effect of yield strength and ductility to fatigue damage

The cumulative damage of aluminium alloys with different yield strength and various ductility due to seismic loads was studied. The responses of an idealized beam with a centered mass at one end and fixed at the other end to El Centro's and Taft's earthquakes are computed by assuming that the alloys are perfectly elastoplastic materials and by using numerical technique. Consequently, the corresponding residual plastic strain can be obtained from the stress-strain relationship. The revised Palmgren-Miner cumulative damage theorem is utilized to calculate the fatigue damage. The numerical results show that in certain cases, the high ductility materials are more resistant to seismic loads than the high yield strength materials. The results also show that if a structure collapse during the earthquake, the collapse always occurs in the very early stage.

Yeh, H. Y.↗
NASA NTRS1974

Recent theories of cavitation damage including non-symmetrical bubble collapse effects

Theories of cavitation damage mechanisms are discussed. Photographic evidence has shown that the actual collapse of bubbles near a symmetry-destroying feature such as a nearby wall results in a toroidal-like collapse, with the final generation of a liquid microjet oriented toward the wall. Numerical analyses indicate that the shock wave intensity emitted during collapse is not likely to be strong enough to be damaging to most materials. It has been determined that actual damage is usually a result of a combination of impact effect of the microjet and the shock wave pressures generated by bubble rebounds.

Hammitt, F. G.↗
NASA NTRS1974

Technique for recovery of voice data from heat damaged magnetic tape

A method for conditioning, and thus enabling retrieval of intelligence from, magnetic tapes after damage from heat has caused the tape to wrinkle and curl severely thereby reducing tape width to less than one-half its original size. The damaged tape is superposed on a first piece of splicing tape with the oxide side of the magnetic tape in contact with the adhesive side of the splicing tape and then carefully smoothed by a special tool. A second piece of splicing tape is placed on the backing side of the magnetic tape then the resulting tape stack is trimmed to the original width of the magnetic tape. After the first piece of splicing tape is carefully removed from the oxide side of the damaged magnetic tape, the resulting magnetic tape is then ready to be placed into a recorder for playback.

Melugin, J. F.↗
NASA NTRS1974

Remote sensing for evaluating post-disaster damage conditions: The Pierre, South Dakota tornado, 23 July 1973

Remote sensing data obtained from aerial reconnaissance of tornado damage to the city of Pierre, South Dakota on July 23, 1973 was evaluated to determine its value as a decision making and management tool in post-disaster restoration activities. The imaging techniques used are briefly discussed, and both aerial and closeup color photographs are provided which were used in the evaluation. The immediate advantages of the data are identified as a 'quick-look' assessment, and a list is given which outlines the additional advantages for which positive rescue and cleanup action may be initiated. Hail and flood damage evaluation, and remote sensing of crop damage due to insect of disease infestation is also briefly described.

Rusche, A. E.↗
NASA NTRS1976

Aerodynamic Characteristics of an A-4B Aircraft with Simulated and Actual Gunfire Damage to One Wing

The aerodynamic characteristics of a damaged McDonnell Douglas A-4B aircraft were studied in the Ames Research Center's 40- by 80-Foot Wind Tunnel. A standard fuselage and three different wings were used. The first wing tested was an undamaged one in which holes had been cut and detachable cover plates installed. Removal of one or more cover plates gave one of fourteen different simulated damage cases. The other two wings tested were damaged by actual gunfire at an Air Force range.

Betzina, M. D.↗
NASA NTRS1977

Theory of ultrasonic diffraction by damage developed in thin laminated composites

The apparent attenuation which would result if certain damage states (transverse cracks and delaminations) are introduced into a graphite/epoxy laminate through which an ultrasonic wave passes is investigated. Experimental data for two different laminates are presented which shows changes in the apparent attenuation of about one db. These changes generally occur at loads which correspond to the range predicted for the formation of the damage. The predicted changes in the attenuation for several simple and common damage states are well within the range of experimental values.

Hayford, D. T.↗