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Results for “ULTRASOUND”

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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Out-of-resonance vibration modulation of ultrasound with a nonlinear oscillator for microcrack detection in a cantilever beam

This Letter reports an out-of-resonance vibro-acoustic modulation (VAM) effect in nonlinear ultrasonic evaluation of a microcracked cantilever beam. We design a model to involve the microcracked cantilever beam in a nonlinear oscillator system whose dynamics is introduced to extend the operating vibration excitation band of the VAM out of resonance. The prototype model exhibits an effective bandwidth four times that of the traditional linear model. The reported VAM effect allows efficiently enhancing the detection, localization, and imaging of various types of microcracks in solid materials at out-of-resonance vibration excitation frequencies.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Effect of triethanolamine:ethylenediamine ratios on CuO nanoparticles prepared by ultrasound irradiation

Coral-spherical-shaped of copper oxide nanoparticles have been successfully synthesized with different ratios of triethanolamine:ethylenediamine surfactant under ultrasonic condition. By controlling the amplitude of the ultrasonic radiation and concentration of metal salt precursors and surfactant, the formation of CuO nanospheres was obtained. Energy dispersive X-ray spectrum confirmed that Cu and O are the only elementary components present with a ratio of approximately 1:1. Furthermore, X-ray powder diffraction spectra for all the examined ratios of CuO showed well crystalline structures. UV-Vis spectroscopy was utilized to estimate the band gap energies of the CuO nanoparticles produced, which were found to be in the range of 2.74 eV to 2.95 eV. The field emission scanning electron micrographs of these nanospheres showed that their dimensions were in the range of 5-30 nm. These results indicate that the triethanolamine:ethylenediamine ratio plays an important role in the formation of different sized CuO nanoparticles, displaying a decrement in particle size with the increment in amount of triethanolamine ratios. This might be the key to synthesizing nanoparticles with specific sizes for various applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Ultrasound-assisted green synthesis of nanocrystalline Co{sub 3}O{sub 4} in the ionic liquid

Cobalt oxide Co{sub 3}O{sub 4} nanoparticles have been synthesized via sonochemical method in an ionic liquid, 1-Ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] for the first time. The crystal structure of Co{sub 3}O{sub 4} nanoparticles has been characterized by using powder X-ray diffraction (XRD). Morphology has been characterized by transmission electron microscopy (TEM). The optical properties were studied by UV-VIS Spectrometer.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Formation of continuous metallic film on quartz studied by noncontact resonant ultrasound spectroscopy

Dynamics of continuous film formation of metallic films on quartz substrates is studied using an electrodeless resonance method. Bare quartz is used as a substrate, and a metallic film is deposited on it. We use antenna transmission technique to measure the evolution of resonance frequencies and internal friction of the substrate during and after deposition, and the morphological transition between discontinuous islands and a continuous film is detected. By comparison with atomic force microscopy images, we confirm that the frequency drop and the internal-friction peak that appear during deposition indicate this transition. We also find that Pt film shows unexpected morphology change after deposition.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Biodiesel production from multi feedstock as feed with direct ultrasound assisted

The objective of this study was to optimize of ratio oil type, ratio oil to methanol and catalyst concentration. The optimization was used Central Composite Design (CCD). Biodiesel was produced with multi stock oil as feed and conducted in direct ultrasonic radiation. Biosonic equiped with ultrasonic generator with a frequency of 28 kHz. Biodiesel produced at a pressure of 1 atm, reaction time of 60 min and temperature 60 ° C. The optimum conditions of volume ratio for Palm and Coconut oil 4:1, KOH catalyst concentration 0.3% and methanol to oil mole ratio 7:1. Biodiesel yield was determined under this condition and obtained 81.105%.

09 BIOMASS FUELS↗
DOE OSTI2016

Synthesis of ZnO/CuO and TiO{sub 2}/CuO nanocomposites for light and ultrasound assisted degradation of a textile dye in aqueous solution

ZnO/CuO and TiO2/CuO nanocomposites with different Zn/Cu and Ti/Cu ratios were prepared using sol-gel method. The obtained composite samples were used as catalyst. Methylene blue was used as a model of textile dye to evaluate their photocatalytic, sonocatalytic and photosonocatalytic activities. X-ray diffraction and energy dispersive X- ray analysis confirmed that only monoclinic CuO and hexagonal wurtzite ZnO structures are present in ZnO/CuO nanocomposites, while in TiO2/CuO nanocomposites monoclinic CuO and anatase TiO2 structures were observed. The degradation of methylene blue indicated that the incorporation of CuO in ZnO/CuO and TiO2/CuO nanocomposites exhibited an appreciable higher photocatalytic activity, which was mainly attributed to the extended photoresponding range and more light energy could be utilized than pure ZnO and TiO2.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Ultrasound – A new approach for non-woven scaffolds investigation

In this study we verified the method of impulse acoustic microscopy as a tool for scaffold evaluation in tissue engineering investigation. Cellulose diacetate (CDA) non-woven 3D scaffold was used as a model object. Scanning electron microscopy and optical microscopy were used as reference methods in order to realize feasibility of acoustic microscopy method in a regenerative medicine field. Direct comparison of the different methods was carried out.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Progress Implementing a Model-Based Iterative Reconstruction Algorithm for Ultrasound Imaging of Thick Concrete

All commercial nuclear power plants (NPPs) in the United States contain concrete structures. These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and the degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Concrete structures in NPPs are often inaccessible and contain large volumes of massively thick concrete. While acoustic imaging using the synthetic aperture focusing technique (SAFT) works adequately well for thin specimens of concrete such as concrete transportation structures, enhancements are needed for heavily reinforced, thick concrete. We argue that image reconstruction quality for acoustic imaging in thick concrete could be improved with Model-Based Iterative Reconstruction (MBIR) techniques. MBIR works by designing a probabilistic model for the measurements (forward model) and a probabilistic model for the object (prior model). Both models are used to formulate an objective function (cost function). The final step in MBIR is to optimize the cost function. Previously, we have demonstrated a first implementation of MBIR for an ultrasonic transducer array system. The original forward model has been upgraded to account for direct arrival signal. Updates to the forward model will be documented and the new algorithm will be assessed with synthetic and empirical samples.

concrete NDE↗
DOE OSTI2018

Anisotropic modeling and joint-MAP stitching for improved ultrasound model-based iterative reconstruction of large and thick specimens

One-sided non-destructive evaluation (NDE) is widely used to inspect materials, such as concrete structures in nuclear power plants (NPP). A widely used method for one-sided NDE is the synthetic aperture focusing technique (SAFT). The SAFT algorithm produces reasonable results when inspecting simple structures. However, for complex structures, such as heavily reinforced thick concrete structures, SAFT results in artifacts and hence there is a need for a more sophisticated inversion technique. Model-based iterative reconstruction (MBIR) algorithms, which are typically equivalent to regularized inversion techniques, offer a powerful framework to incorporate complex models for the physics, detector miscalibrations and the materials being imaged to obtain high quality reconstructions. Previously, we have proposed an ultrasonic MBIR method that signifcantly improves reconstruction quality compared to SAFT. However, the method made some simplifying assumptions on the propagation model and did not disucss ways to handle data that is obtained by raster scanning a system over a surface to inspect large regions. In this paper, we propose a novel MBIR algorithm that incorporates an anisotropic forward model and allows for the joint processing of data obtained from a system that raster scans a large surface. We demonstrate that the new MBIR method can produce dramatic improvements in reconstruction quality compared to SAFT and suppresses articfacts compared to the perviously presented MBIR approach.

Almansouri, Hani↗
DOE OSTI2018

On the Usage of Ultrasound Computational Models for Decision Making Under Ambiguity

Computer modeling and simulation is becoming pervasive within the non-destructive evaluation (NDE) industry as a convenient tool for designing and assessing inspection techniques. This raises a pressing need for developing quantitative techniques for demonstrating the validity and applicability of the computational models. Computational models provide deterministic results based on deterministic and well-defined input, or stochastic results based on inputs defined by probability distributions. However, computational models cannot account for the effects of personnel, procedures, and equipment, resulting in ambiguity about the efficacy of inspections based on guidance from computational models only. In addition ambiguity arises when model inputs, such as the representation of realistic cracks, cannot be defined deterministically, probabilistically, or by intervals. In this work, Pacific Northwest National Laboratory demonstrates the ability of computational models to represent field measurements under known variabilities, and quantify the differences using maximum amplitude and power spectrum density metrics. Sensitivity studies are also conducted to quantify the effects of different input parameters on the simulation results.

Dib, Gerges↗
DOE OSTI2018

Non-Destructive Inspection Approach Using Ultrasound to Identify the Material State for Amorphous and Semi-Crystalline Materials

At present, there are many methods to identify the temperature and phase of a material using invasive techniques. However, most current methods require physical contact or implicit methods utilizing light reflectance of the specimen. In this paper, we present a nondestructive inspection method using ultrasonic wave technology that circumvents these disadvantages to identify phase change regions and infer the temperature state of a material. In the present study an experiment is performed to monitor the time of flight within a wax as it undergoes melting and the subsequent cooling. Results presented in this work show a clear relationship between a material’s speed of sound and its temperature. The phase change transition of the material is clear from the time of flight results, and in the case of the investigated material, this change in the material state occurs over a range of temperatures. The range of temperatures over which the wax material melts is readily identified by speed of sound represented as a function of material temperature. The melt temperature, obtained acoustically, is validated using Differential Scanning Calorimetry (DSC), which uses shifts in heat flow rates to identify phase transition temperature ranges. Lastly, the investigated ultrasonic NDE method has direct applications in many industries, including oil and gas, food and beverage, and polymer composites, in addition to many implications for future capabilities of nondestructive inspection of multi-phase materials.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Observation of maxon-like ultrasound in elastic metabeam

We observe maxon-like dispersion of ultrasonic guided waves in elastic metamaterials consisting of a rectangular beam and an array of cylindrical resonators. The pillars act as asymmetric resonators that induce a strong modal hybridization. We experimentally observe the strongly localized maxon mode with zero group velocity. Our study also demonstrates a unique feature of the maxon with a down-shifting peak frequency in space. To reveal the fundamental mechanism, we conduct comprehensive numerical studies on all frieze group symmetries and key geometric parameters.

Materials Science↗
DOE OSTI2019

Generation of high-intensity ultrasound through shock propagation in liquid jets

We investigated the generation and propagation of ultrasonic pressure waves produced by focused x-ray free-electron laser pulses in 14 to 30 μm diameter liquid water microjets. The pressure waves formed through reflections, at the surface of the microjets, of the initial shock launched in the liquid by the x-ray pulse. These waves developed a characteristic geometric pattern which is related to, but different from, the shock structures of supersonic gas jets. Fully developed waves had initial peak pressures ranging from less than –24 MPa to approximately 100 MPa, which exceed the compressive and tensile strengths of many materials, and correspond to extreme sound intensities on the order of 1 GW/m 2 and sound pressure levels above 270 dB (re: 1 μ Pa). The amplitudes and intensities were limited by the wave destroying its own propagation medium though cavitation, and therefore these ultrasonic waves in jets are one of the most intense propagating sounds that can be generated in liquid water. The pressure of the initial shock decayed exponentially, more rapidly in thinner jets, and the decay length was proportional to the jet diameter within the accuracy of measurements. Extrapolating our results to thinner jets, we find that the pressure waves may damage protein crystals carried by liquid jets in x-ray laser crystallography experiments conducted at megahertz repetition rates.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗