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Results for “nondestructive examination”

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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Effect of cycling on the lithium/electrolyte interface in organic electrolytes

Nondestructive methods such as ac impedance spectroscopy and microcalorimetry are used to study the effect of cell cycling on the lithium/electrolyte interface. The reactivity of both uncycled and cycled lithium towards various electrolytes is examined by measuring the heat evolved from the cells under open-circuit conditions at 25 C by microcalorimetry. Cycled cells at the end of charge/discharge exhibited considerably higher heat output compared with the uncycled cells. After 30 d of storage, the heat output of the cycled cells is similar to that of the uncycled cells. The cell internal resistance increases with cycling, and this is attributed to the degradation of the electrolyte with cycling.

Surampudi, S.↗
NASA NTRS1995

Optical Detection Of Fractures In Ceramic Diaphragms

Simple optical technique enables quick, nondestructive inspection of surfaces of ceramic diaphragms and disks for fractures and discontinuities. Involves reflecting beam of light from laser at glancing angle of about 20 degrees to 25 degrees off surface inspected and examining pattern of reflected light on suitable viewing surface as beam swept across surface. When fracture present, reflection pattern separates into two or more speckled spots. Technique applied in inspection of ceramic diaphragms bearing electronic circuits. Also useful in detection of fatigue cracks on aircraft.

Laue, Eric G.↗
NASA NTRS1985

Fourier transform-infrared spectroscopic methods for microbial ecology: analysis of bacteria, bacteria-polymer mixtures and biofilms

Fourier transform-infrared (FT-IR) spectroscopy has been used to rapidly and nondestructively analyze bacteria, bacteria-polymer mixtures, digester samples and microbial biofilms. Diffuse reflectance FT-IR (DRIFT) analysis of freeze-dried, powdered samples offered a means of obtaining structural information. The bacteria examined were divided into two groups. The first group was characterized by a dominant amide I band and the second group of organisms displayed an additional strong carbonyl stretch at approximately 1740 cm-1. The differences illustrated by the subtraction spectra obtained for microbes of the two groups suggest that FT-IR spectroscopy can be utilized to recognize differences in microbial community structure. Calculation of specific band ratios has enabled the composition of bacteria and extracellular or intracellular storage product polymer mixtures to be determined for bacteria-gum arabic (amide I/carbohydrate C-O approximately 1150 cm-1) and bacteria-poly-beta-hydroxybutyrate (amide I/carbonyl approximately 1740 cm-1). The key band ratios correlate with the compositions of the material and provide useful information for the application of FT-IR spectroscopy to environmental biofilm samples and for distinguishing bacteria grown under differing nutrient conditions. DRIFT spectra have been obtained for biofilms produced by Vibrio natriegens on stainless steel disks. Between 48 and 144 h, an increase in bands at approximately 1440 and 1090 cm-1 was seen in FT-IR spectra of the V. natriegens biofilm. DRIFT spectra of mixed culture effluents of anaerobic digesters show differences induced by shifts in input feedstocks. The use of flow-through attenuated total reflectance has permitted in situ real-time changes in biofilm formation to be monitored and provides a powerful tool for understanding the interactions within adherent microbial consortia.

NASA Discipline Number 61-10↗
NASA NTRS1975

Failure analysis of electronic parts: Laboratory methods

Failure analysis test methods are presented for use in analyzing candidate electronic parts and in improving future design reliability. Each test is classified as nondestructive, semidestructive, or destructive. The effects upon applicable part types (i.e. integrated circuit, transitor) are discussed. Methodology is given for performing the following: immersion tests, radio graphic tests, dewpoint tests, gas ambient analysis, cross sectioning, and ultraviolet examination.

Anstead, R. J.↗
NASA NTRS1991

Quantitative nondestructive evaluation of materials and structures

An experimental investigation was undertaken to quantify damage tolerance and resistance in composite materials impacted using the drop-weight method. Tests were conducted on laminates of several different carbon-fiber composite systems, such as epoxies, modified epoxies, and amorphous and semicrystalline thermoplastics. Impacted composite specimens were examined using destructive and non-destructive techniques to establish the characteristic damage states. Specifically, optical microscopy, ultrasonic, and scanning electron microscopy techniques were used to identify impact induced damage mechanisms. Damage propagation during post impact compression was also studied.

Smith, Barry T.↗
NASA NTRS1981

Some aspects of analytical chemistry as applied to water quality assurance techniques for reclaimed water: The potential use of X-ray fluorescence spectrometry for automated on-line fast real-time simultaneous multi-component analysis of inorganic pollutants in reclaimed water

The potential use of isotopically excited energy dispersive X-ray fluorescence (XRF) spectrometry for automated on line fast real time (5 to 15 minutes) simultaneous multicomponent (up to 20) trace (1 to 10 parts per billion) analysis of inorganic pollutants in reclaimed water was examined. Three anionic elements (chromium 6, arsenic and selenium) were studied. The inherent lack of sensitivity of XRF spectrometry for these elements mandates use of a preconcentration technique and various methods were examined, including: several direct and indirect evaporation methods; ion exchange membranes; selective and nonselective precipitation; and complexation processes. It is shown tha XRF spectrometry itself is well suited for automated on line quality assurance, and can provide a nondestructive (and thus sample storage and repeat analysis capabilities) and particularly convenient analytical method. Further, the use of an isotopically excited energy dispersive unit (50 mCi Cd-109 source) coupled with a suitable preconcentration process can provide sufficient sensitivity to achieve the current mandated minimum levels of detection without the need for high power X-ray generating tubes.

Ling, A. C.↗
NASA NTRS1998

RSRM Nozzle Anomalous Throat Erosion Investigation Overview

In September, 1996, anomalous pocketing erosion was observed in the aft end of the throat ring of the nozzle of one of the reusable solid rocket motors (RSRM 56B) used on NASA's space transportation system (STS) mission 79. The RSRM throat ring is constructed of bias tape-wrapped carbon cloth/ phenolic (CCP) ablative material. A comprehensive investigation revealed necessary and sufficient conditions for occurrence of the pocketing event and provided rationale that the solid rocket motors for the subsequent mission, STS-80, were safe to fly. The nozzles of both of these motors also exhibited anomalous erosion similar to, but less extensive than that observed on STS-79. Subsequent to this flight, the investigation to identify both the specific causes and the corrective actions for elimination of the necessary and sufficient conditions for the pocketing erosion was intensified. A detailed fault tree approach was utilized to examine potential material and process contributors to the anomalous performance. The investigation involved extensive constituent and component material property testing, pedigree assessments, supplier audits, process audits, full scale processing test article fabrication and evaluation, thermal and thermostructural analyses, nondestructive evaluation, and material performance tests conducted using hot fire simulation in laboratory test beds and subscale and full scale solid rocket motor static test firings. This presentation will provide an over-view of the observed anomalous nozzle erosion and the comprehensive, fault-tree based investigation conducted to resolve this issue.

Clinton, R. G., Jr.↗
NASA NTRS1987

A nondestructive technique for predicting the strength remaining in filament wound composites subjected to low-level impact

A model for predicting the fracture strength of homogeneous materials is proposed. Impacted FWC samples were evaluated using ultrasonic testing and an X-ray dye penetration method. The ability of the model to measure fracture strength was also examined. The relation between attenuation and velocity measurements is studied. It is observed that the X-ray method is not useful for predicting fracture strength because the dye could not penetrate the matrix. It is noted that fracture strength predictions derived from the fracture mechanical model and the ultrasonic measurements correlate well with actual measured fracture strengths.

Madaras, E. I.↗
NASA NTRS1995

Nondestructive Determination of Heat/Fire Damage to Polymer- Matrix Composites Using Obliquely Insonified Ultrasonic Waves

Heat and fire damage to composite structures cause loss of strength that cannot be detected by current NDE methods unless physical damage occurs. Further, there is a lack of fundamental understanding of the mechanism of damage from thermal exposure of organic matrix composites to elevated temperatures. Information compiled from field reports and lab experiments increasingly suggests that there is material degradation and it is not necessarily involved with the introduction of physical defects. In recent years, various researchers examined the potential to identifying thermal degradation to organic matrix composites prior to delamination. The methods that were used include: ultrasonics, backscattered X-ray, eddy current, thermography, drift and LPF spectroscopies, acousto-ultrasonics and hardness testing. None of these methods were able to correlate NDE results with loss of mechanical properties.

polymer-matrix composite fire damage NDE nondestru↗
NASA NTRS1989

Fractography of composite delamination

Delamination is a major failure mode of carbon fiber organic matrix composites. It can occur under a variety of loading conditions. Efforts to develop predictive models of the delamination of carbon fiber composites are hampered by a lack of information about the micromechanics of impact damage and delamination growth. Crack formation and propagation in these materials cannot be observed in sufficient detail to determine micro-damage using currently available nondestructive methods such as acoustic backscattering or x ray imaging. Consequently, destructive methods are required. Delamination of composites in Mode I, Mode II and after low energy impact loads were investigated using metallographic techniques of potting the failed specimens, sectioning and examining the cut sections for damage modes.

Bascom, W. D.↗
DOE OSTI2021

Thermal impacts on nondestructive analysis measurements of uranium hexafluoride

A series of nondestructive assay measurements were performed before, during, and after localized heating of an industrial standard 12B cylinder of uranium hexafluoride to replicate dose variations previously observed on commercial 30B cylinders. While cylinders represent a closed system, enrichment measurements may be impacted by altered uranium and daughter product distributions due to sublimation. A series of measurements were performed to examine localized heating impacts on dose rates, ratios of uranium and daughter product distributions, and measured 235 U enrichment as calculated by two different approaches. The less complex enrichment meter approaches were found to be more robust and less prone to deviation than isotope ratio approaches such as FRAM, but the impact can be minimized by using observable dose changes to avoid impacted areas.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
NASA NTRS1993

NDE of titanium alloy MMC rings for gas turbine engines

Progress in the processing and fabrication of metal matrix composites (MMC's) requires appropriate mechanical and nondestructive testing methods. These methods are needed to characterize properties, assess integrity, and predict the life of engine components such as compressor rotors, blades, and vanes. Capabilities and limitations of several state-of-the-art nondestructive evaluation (NDE) technologies are investigated for characterizing titanium MMC rings for gas turbine engines. The use of NDE technologies such as x-ray computed tomography, radiography, and ultrasonics in identifying fabrication-related problems that caused defects in components is examined. Acousto-ultrasonics was explored to assess degradation of material mechanical properties by using stress wave factor and ultrasonic velocity measurements before and after the burst testing of the rings.

Baaklini, George Y.↗
NASA NTRS1978

Detection of internal defects in a liquid natural gas tank by use of infrared thermography

The use of an infrared scanning technique to detect defects in the secondary barrier of a liquid natural gas tank is described. The method works by detecting leak-caused temperature differences as low as 0.2 K, but can provide only an approximate idea of the extent of the defect. The nondestructive method was tested in a study of a LNG tank already at its location in a ship; the secondary barrier was located inside the tank wall. Defective areas indicated by the infrared radiometric measurements were confirmed by other probe techniques and by physical examination.

Kantsios, A. G.↗
NASA NTRS1998

Thickness-Independent Ultrasonic Imaging Applied to Abrasive Cut-Off Wheels: An Advanced Aerospace Materials Characterization Method for the Abrasives Industry. A NASA Lewis Research Center Technology Transfer Case History

Abrasive cut-off wheels are at times unintentionally manufactured with nonuniformity that is difficult to identify and sufficiently characterize without time-consuming, destructive examination. One particular nonuniformity is a density variation condition occurring around the wheel circumference or along the radius, or both. This density variation, depending on its severity, can cause wheel warpage and wheel vibration resulting in unacceptable performance and perhaps premature failure of the wheel. Conventional nondestructive evaluation methods such as ultrasonic c-scan imaging and film radiography are inaccurate in their attempts at characterizing the density variation because a superimposing thickness variation exists as well in the wheel. In this article, the single transducer thickness-independent ultrasonic imaging method, developed specifically to allow more accurate characterization of aerospace components, is shown to precisely characterize the extent of the density variation in a cut-off wheel having a superimposing thickness variation. The method thereby has potential as an effective quality control tool in the abrasives industry for the wheel manufacturer.

Roth, Don J.↗
DOE OSTI2022

Bioaccumulation of Mercury and Radiocesium in Waterfowl Introduced to a Site with Legacy Contamination

Despite the propensity of waterfowl species to readily accumulate anthropogenic contaminants within polluted environments, few studies have examined bioaccumulation rates over time when entering such a contaminated site. We examined mercury (Hg) and radiocesium ( 137 Cs) bioaccumulation over time in two waterfowl species released into a wetland system containing legacy contamination on the US Department of Energy's Savannah River Site in South Carolina. Released birds were collected at select time intervals over an exposure period of 94 days. We quantified total Hg concentrations in blood, muscle, and liver tissues, and 137 Cs activity in whole-body and muscle tissues. The relationship between the contaminant burdens of different body tissue types was examined over time. Likely a result of microhabitat selection, mallards in our study readily accumulated both Hg and 137 Cs at consistent rates over time within our study system, while ring-neck ducks did not. The findings demonstrated that whole blood can be used as a robust, nondestructive sampling alternative to estimate Hg burdens within muscle and liver, and whole-body 137 Cs activity is a good predictor of muscle burdens. Understanding such bioaccumulation information in waterfowl is useful for the assessment of the potential health risk in wildlife, as well as being important for human risk assessment toward the consumption of popular game species. Environ Toxicol Chem 2022;41:2479–2487. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1972

Fault determinations in electroexplosive devices by nondestructive techniques

Several nondestructive test techniques were developed for electroexplosive devices. The bridgewire responds, when pulsed with a safe level current, by generating a characteristic heating curve. The response is indicative of the electrothermal behavior of the bridgewire-explosive interface. Bridgewires which deviate from the characteristic heating curve were dissected and examined to determine the cause of the abnormality. Deliberate faults were fabricated into squibs. The relationship of the specific abnormality and the fault associated with it is demonstrated.

Menichelli, V. J.↗
NASA NTRS2017

A New Method of Absorption-Phase Nanotomography for 3D Observation of Mineral-Organic-Water Textiles and its Application to Pristine Carbonaceous Chondrites

Pristine carbonaceous chondrites contain fine-grained matrix, which is composed largely of amorphous silicates, sub-micron silicate and sulfide crystals, and organic materials. They are regarded as primitive dust in the early Solar System that have suffered minimal alteration in their parent bodies. The matrix generally has different lithologies; some of them are unaltered but some are more or less aqueously altered. Their textures have been examined in 2D usually by FE-SEM/EDS, TEM/EDS, nano-SIMS and micro-XRD. Observation of their complex fine textures, such as spatial relation between different lithologies in 3D, is important for understanding aggregation and alteration processes. Synchrotron radiation (SR)-based X-ray tomography reveals 3D structures nondestructively with high spatial resolution of approximately greater than 100 nm. We have developed a new technique using absorption contrasts called "dual-energy tomography" (DET) to obtain 3D distribution of minerals at SPring-8, SR facility in Japan, and applied successfully to Itokawa particles. Phase and absorption contrast images can be simultaneously obtained in 3D by using "scanning-imaging x-ray microscopy" (SIXM) at SPring-8, which can discriminate between void, water and organic materials. We applied this technique combined with FIB micro-sampling to carbonaceous chondrites to search for primitive liquid water. In this study, we combined the DET and SIXM to obtain three dimensional submicron-scale association between minerals, organic materials and water and applied this to pristine carbonaceous chondrites.

Tsuchiyama, A.↗
NASA NTRS1971

Interrelationship of nondestructive testing to fault determination.

Several nondestructive test techniques have been developed for electroexplosive devices. The bridgewire will respond, when pulsed with a safe level current, by generating a characteristic heating curve. The response is indicative of the electrothermal behavior of the bridgewire-explosive interface. Bridgewires which deviate from the characteristic heating curve have been dissected and examined to determine the cause for the abnormality. Deliberate faults have been fabricated into squibs. The relationship of the specific abnormality and the fault associated with it is discussed.

Menichelli, V. J.↗