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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Non-contact optical system for detecting ultrasound waves from a surface

A system for detecting pressure, acoustic or ultrasound waves within an entity having a surface including the steps of attaching a signal converting material to the surface. The waves are generated by direct ejection from the surface, generation via energy deposition on the surface, generated spontaneously or, generated by directing light energy to the light absorbing target. The absorbing target subsequently generates acoustic pressure waves. The acoustic waves propagate to the surface of the entity and the signal converting material, wherein the acoustic pressure waves create vibrations in the signal converting material; and detecting the waves in the signal converting material with an optical detection system. Information about the absorbing target is obtained by the absorbing target reflecting the waves. The signal converting material can be a gel-like material containing optical elements, a multi-layer patch, or other material.

Demos, Stavros G.↗
DOE OSTI2020

Apparatus and method for visualization of particles suspended in a fluid and fluid flow patterns using ultrasound

An apparatus and method for real-time visualization of particulate matter suspended in a static or flowing fluid and fluid flow patterns in a pipe, tube, conduit, or other container, are described. Ultrasonic scanning and detection of scattered sound from the particles in the fluid create a real-time image of the particles, or of flow patterns in the liquid. A mechanical wobbler directs a piezoelectric transducer over a chosen angle in an oscillatory manner. The transducer is operated in a pulse-echo mode wherein the same transducer detects the return signal from the target region through which particles are passing and/or a flow is present. The pulse-echo measurements are made rapidly and continuously during a single sweep of the transducer over the chosen angle. Received signals are processed in the ultrasound scanner electronics module and displayed as an image in real-time.

42 ENGINEERING↗
DOE OSTI2015

Results from the commissioning of a multi-modal endoscope for ultrasound and time of flight PET

The EndoTOFPET-US collaboration has developed a multi-modal imaging system combining Ultrasound with Time-of-Flight Positron Emission Tomography into an endoscopic imaging device. The objective of the project is to obtain a coincidence time resolution of about 200 ps FWHM and to achieve about 1 mm spatial resolution of the PET system, while integrating all the components in a very compact detector suitable for endoscopic use. This scanner aims to be exploited for diagnostic and surgical oncology, as well as being instrumental in the clinical test of new biomarkers especially targeted for prostate and pancreatic cancer. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Online and noninvasive monitoring of battery health at negative-half cell in all-vanadium redox flow batteries using ultrasound

Hydrogen evolution is one of the major side reactions that is detrimental to the health of all-vanadium redox flow batteries, especially for long-term cycling. Effective, low-cost, and accurate online prediction and detection methods for hydrogen generation are not yet available. In this work, we designed an online, noninvasive ultrasonic probing approach for monitoring the state of charge (SoC), predicting the hydrogen generation, and detecting hydrogen gas bubbles in anolyte solutions. The technique employs a pulse-echo method to measure the sound speed and the acoustic attenuation coefficient of the anolyte solution. Through static offline experiments and online in operando experiments, we have demonstrated that when hydrogen gas is generated in anolyte solutions, large variations are observed in both sound speed and acoustic attenuation coefficient measurements. We found that the variations of acoustic attenuation coefficient are highly correlated (correlation coefficients >0.9) with the gas flow rate. In conclusion, the designed acoustic method can monitor the SoC of anolyte, predict the hydrogen generation, and detect the presence of gas bubbles in an anolyte solution and, thus, provide information about the state of health for operation and management of flow battery systems.

25 ENERGY STORAGE↗
DOE OSTI2013

Examination of the epicentral waveform for laser ultrasound in the melting regime

A laser ultrasonic source just below the ablation regime is examined by recording an epicentral waveform in a high purity tungsten sample. Using pulse energy as a parameter, a slight delay in the shear wave arrival time is observed upon transition to the melting regime. This phenomenon is attributed to a change in character of the ultrasonic source. In the thermoelastic regime, shear waves are generated by mode conversion at the sample surface of longitudinal waves emanating from subsurface sources. Just above the melting threshold, a molten pool forms in the center of the generation volume. Shear waves are not supported by the molten pool. As a result, shear waves generated from off-axis thermoelastic sources are weighted more heavily. This results in a delay of the shear wave arrival time.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Laser-Induced CO 2 Generation from Gold Nanorod-Containing Poly(propylene carbonate)-Based Block Polymer Micelles for Ultrasound Contrast Enhancement

Poly(propylene carbonate) (PPC) decomposes at high temperature to release CO 2 . Here, this CO 2 -generation temperature of PPC can be reduced down to less than 80 °C with the aid of a photoacid generator (PAG). In the present work, we demonstrate that using an additional helper component, surface plasmonic gold nanorods (GNRs), the PPC degradation reaction can also be initiated by near infrared (NIR) irradiation. For this purpose, a PPC-containing nanoparticle formulation was developed in which PPC-based amphiphilic block copolymers (BCPs), poly(poly(ethylene glycol) methacrylate-b-propylene carbonate-b-poly(ethylene glycol) methacrylate) (PPEGMA-PPC-PPEGMA), were self-assembled with GNRs and PAG molecules via solvent exchange; under NIR irradiation GNRs produce heat that can cause PPC to decompose into CO 2 , and PAG (after UV pre-treatment) catalyzes this PPC degradation process.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Waterless Coupling of Ultrasound from Planar Contact Transducers to Curved and Irregular Surfaces during Non-destructive Ultrasonic Evaluations

The Applied Physics group at the Pacific The Applied Physics group at the Pacific Northwest National Laboratory (PNNL) in Richland, WA has evaluated a method for waterless/liquidless coupling of ultrasonic energy from planar ultrasonic contact transducers to irregular test surfaces for ultrasonic non-destructive evaluation applications. Dry couplant material placed between a planar transducer face and a curved or uneven steel or plastic surface allows for effective sound energy coupling and preserves the integrity of the planar transducer sound field by serving as an acoustic impedance matching layer, providing good surface area contact between geometrically dissimilar surfaces and conforming to rough and unsmooth surfaces. Sound fields radiating from planar ultrasonic contact transducers coupled to curved and uneven surfaces using the dry coupling method were scanned and mapped using a Pinducer receiver connected to a raster scanner. Transducer sound field coverage at several ultrasonic frequencies and several distances from the transducer contact locations were found to be in good agreement with theoretical beam divergence and sound field coverage predictions for planar transducers coupled to simple, planar surfaces. This method is valuable for applications that do not allow for the use of traditional liquid-based ultrasonic couplants due to the sensitivity of the test materials to liquids and for applications that might otherwise require curved transducers or custom coupling wedges. The selection of dry coupling material is reported along with the results of theoretical sound field predictions, the laboratory testing apparatus and the empirical sound field data.

Couplant↗
DOE OSTI2012

Dissolution of Biodiesel Precipitates via Ultrasound

Recently there has been renewed interest in expanding the role of biodiesel in the energy plan for the United States. With the rising cost of petroleum and the recognized need to utilize domestic fuel resources to improve the nation’s energy security, biofuels, such as biodiesel, offer a promising alternative to help meet the country’s energy needs (especially for transportation). Additional concerns about global warming have also led to calls for more renewable energy sources, including alternative fuels. Biodiesel is made from renewable resources such as soybean oil, other plant oils and animal fat. It can be used in diesel engines and burners (to heat homes) with few or no modifications and can be used either neat (B100), or blended with petroleum diesel (commonly as 20% biodiesel, B20).

Biodiesel↗
DOE OSTI2024

Ultrasound preliminary cyber-physical evaluation

In this assessment, we focused on identifying unwanted RF emissions from the subject devices. This consisted of two major approaches: 1) Monitor for emitted RF during operation and ensure it is within expected bounds. 2) Inspect circuit board construction for any geometry or design patterns that could lead to RF emissions, whether intentional or unintentional. These patterns include: a) Single-ended PCB traces that could operate as an antenna. b) Insufficient shielding around typically “noisy” components such as switching power supplies. c) Free-hanging high-speed signal wires with no shielding that could emit RF. Suspicious components and design patterns were given a plausible reason to be included in the design. Any suspicious components or patterns warranted reason for deeper investigation. After more in-depth analysis no components were found to be intentionally malicious or had unexpected functionality.

42 ENGINEERING↗