Search NASA⌕ Search

SEARCH · Search NASA

Results for “Conformal ablator”

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.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Epoxy / Silicone Potting Material Removal for Greater Recovery of Circuit Boards

This report documents an exploratory research project, “Epoxy/Silicone Potting Material Removal for Greater Recovery of Circuit Boards,” that investigated micro abrasion and laser ablation as potential cost effective methods for removal of epoxy and silicone potting material from printed circuit boards (PCBs) to expose components for testing and repair. The ability to cost effectively remove such PCB potting materials will improve PCB repair, remanufacture, and reuse opportunities with potential for sizable reductions in material use, E-waste, and energy. Laser ablation was identified as a method potentially warranting further investigation, in particular for epoxy based potting materials.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Conformal Avoidance of Normal Organs at Risk by Perfusion-Modulated Dose Sculpting in Tumor Single-Dose Radiation Therapy

Although 24 Gy single-dose radiation therapy (SDRT) renders >90% 5-year local relapse-free survival in human solid tumor lesions, SDRT delivery is not feasible in ∼50% of oligometastatic lesions owing to interference by dose/volume constraints of a serial organ at risk (OAR). Conformal OAR avoidance is based on a hypothetical model positing that the recently described SDRT biology specifically permits volumetric subdivision of the SDRT dose, such that high-intensity vascular drivers of SDRT lethality, generated within a major tumor subvolume exposed to a high 24 Gy dose (high-dose planning target volume [PTV{sub HD]}), would equilibrate SDRT signaling intensity throughout the tumor interstitial space, rendering bystander radiosensitization of a minor subvolume (perfusion-modulated dose sculpting PTV [PTV{sub PMDS}]), dose-sculpted to meet a serial OAR dose/volume constraint. An engineered PTV{sub PMDS} may thus yield tumor ablation despite PMDS dose reduction and conformally avoiding OAR exposure to a toxic dose.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Design and evaluation of an open-source, conformable skin-cooling system for body magnetic resonance guided focused ultrasound treatments

Magnetic resonance guided focused ultrasound (MRgFUS) treatment of tumors uses inter-sonication delays to allow heat to dissipate from the skin and other near-field tissues. Despite inter-sonication delays, treatment of tumors close to the skin risks skin burns. This work has designed and evaluated an open-source, conformable, skin-cooling system for body MRgFUS treatments to reduce skin burns and enable ablation closer to the skin. A MR-compatible skin cooling system is described that features a conformable skin-cooling pad assembly with feedback control allowing continuous flow and pressure maintenance during the procedure. System performance was evaluated with hydrophone, phantom and in vivo porcine studies. Sonications were performed 10 and 5 mm from the skin surface under both control and forced convective skin-cooling conditions. 3D MR temperature imaging was acquired in real time and the accumulated thermal dose volume was measured. Gross analysis of the skin post-sonication was further performed. Device conformability was demonstrated at several body locations. Hydrophone studies demonstrated no beam aberration, but a 5–12% reduction of the peak pressure due to the presence of the skin-cooling pad assembly in the acoustic near field. Phantom evaluation demonstrated there is no MR temperature imaging precision reduction or any other artifacts present due to the coolant flow during MRgFUS sonication. The porcine studies demonstrated skin burns were reduced in size or eliminated when compared to the control condition. An open-source design of an MRgFUS active skin cooling system demonstrates device conformability with a reduction of skin burns while ablating superficial tissues.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Satellite Enveloped with STITCHED Engineering Sensors for Detection of Approaching Objects

Today as well as tomorrows spaceborne assets impact almost all areas of national and nuclear security. Spaceborne assets can not only collect and disseminate valuable data, well beyond just the visual, but also track terrestrial-based mobile assets in real-time, and active spaceborne platforms potentially pose serious risk to vulnerable earth-based systems and infrastructures. The capability to defend national spaceborne assets from attack/interference is critical for security interests. This effort supports this mission through the cost-effective preeminent detection of approaching threats to our nation’s vital resources, in order to help secure and trust these high-value assets against the threats of tomorrow. This project develops novel fabrication techniques for conformal, low-profile and lightweight leakywave antenna (LWA) detection/imaging systems, which fuses technical embroidery (TE) and laser ablation (LA) processes with LWA design. Technical embroidery is an emerging field in additive textile manufacturing where flexible materials and functionalized fabrics are created for a wide variety of uses and purposes, while laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. Here, thin, conformal antenna designs are designed, modeled and fabricated using both TE and LA, to create lightweight, flexible and conformal object detection and imaging radars. This novel development ensures our nation’s ability to field advanced lightweight and conformal technologies to protect spaceborne assets.

42 ENGINEERING↗
DOE OSTI2023

The yeast ALA synthase C‐terminus positively controls enzyme structure and function

Abstract 5‐Aminolevulinic acid synthase (ALAS) is a pyridoxal 5′‐phosphate (PLP)‐dependent enzyme that catalyzes the first and rate‐limiting step of heme biosynthesis in α‐proteobacteria and several non‐plant eukaryotes. All ALAS homologs contain a highly conserved catalytic core, but eukaryotes also have a unique C‐terminal extension that plays a role in enzyme regulation. Several mutations in this region are implicated in multiple blood disorders in humans. In Saccharomyces cerevisiae ALAS (Hem1), the C‐terminal extension wraps around the homodimer core to contact conserved ALAS motifs proximal to the opposite active site. To determine the importance of these Hem1 C‐terminal interactions, we determined the crystal structure of S. cerevisiae Hem1 lacking the terminal 14 amino acids (Hem1 ΔCT). With truncation of the C‐terminal extension, we show structurally and biochemically that multiple catalytic motifs become flexible, including an antiparallel β‐sheet important to Fold‐Type I PLP‐dependent enzymes. The changes in protein conformation result in an altered cofactor microenvironment, decreased enzyme activity and catalytic efficiency, and ablation of subunit cooperativity. These findings suggest that the eukaryotic ALAS C‐terminus has a homolog‐specific role in mediating heme biosynthesis, indicating a mechanism for autoregulation that can be exploited to allosterically modulate heme biosynthesis in different organisms.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Cryo-EM structure of adeno-associated virus 4 at 2.2 Å resolution

Adeno-associated virus (AAV) is the vector of choice for several approved gene-therapy treatments and is the basis for many ongoing clinical trials. Various strains of AAV exist (referred to as serotypes), each with their own transfection characteristics. Here, a high-resolution cryo-electron microscopy structure (2.2 Å) of AAV serotype 4 (AAV4) is presented. The receptor responsible for transduction of the AAV4 clade of AAV viruses (including AAV11, AAV12 and AAVrh32.33) is unknown. Other AAVs interact with the same cell receptor, adeno-associated virus receptor (AAVR), in one of two different ways. AAV5-like viruses interact exclusively with the polycystic kidney disease-like 1 (PKD1) domain of AAVR, while most other AAVs interact primarily with the PKD2 domain. A comparison of the present AAV4 structure with prior corresponding structures of AAV5, AAV2 and AAV1 in complex with AAVR provides a foundation for understanding why the AAV4-like clade is unable to interact with either PKD1 or PKD2 of AAVR. The conformation of the AAV4 capsid in variable regions I, III, IV and V on the viral surface appears to be sufficiently different from AAV2 to ablate binding with PKD2. Differences between AAV4 and AAV5 in variable region VII appear to be sufficient to exclude binding with PKD1.

59 BASIC BIOLOGICAL SCIENCES↗