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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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229 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Solvent depression of transition temperature to selectively stimulate actuation of shape memory polymer foams

An embodiment of the invention is a shape memory polymer (SMP) foam designed to recover its original shape through exposure to a solvent. Thermo-responsive SMPs are polymers designed to maintain a programmed secondary shape until heated above their transition temperature, upon which the polymer recovers its original, or primary, shape. The thermo-responsive SMP foam is programmed to its secondary shape prior to use, typically compression of the foam to a small volume, and remains in this programmed shape until exposed to a selected solvent such as dimethyl sulfoxide or ethyl alcohol. Upon exposure to the solvent, the transition temperature of the SMP foam decreases below the temperature of the environment and the SMP foam actuates to its primary shape. The SMP foam is tailored to actuate upon exposure to specific solvents while minimizing or preventing actuation when exposed to water or other solvents. This selective solvent actuation can be used to increase working time of a SMP foam device, that is, the time allowed for use of a device without undesired actuation, while maintaining functional SMP actuation. Solvent actuated SMP foams can be used in various applications including, but not limited to, treatment of aneurysms and arterio-venous malformations, tissue engineering, and wound healing.

Boyle, Anthony↗
DOE OSTI2022

Engineered FGF1 and FGF2 compositions and methods of use thereof

Engineered FGF1 and FGF2 polypeptides, polynucleotides encoding these polypeptides and DNA constructs, vectors and compositions including these engineered polypeptides are provided herein. The engineered FGF1 and FGF2 polypeptides are more stable than their wild-type counterparts and may be more effective at treating a variety of conditions that FGF1 and FGF2 are useful for treating such as wound healing.

Thallapuranam, Suresh Kumar↗
DOE OSTI2022

Bi-terminal pegylated integrin-binding peptides and methods of use thereof

The present invention provides bi-terminal PEGylated peptide conjugates that target an integrin such as αvβ6 integrin. In particular embodiments, the peptide conjugates of the present invention further comprise a biological agent such as an imaging agent or a therapeutic agent, e.g., covalently attached to one of the PEG moieties. The peptide conjugates of the present invention are particularly useful for imaging a tumor, organ, or tissue and for treating integrin-mediated diseases and disorders such as cancer, inflammatory diseases, autoimmune diseases, chronic fibrosis, chronic obstructive pulmonary disease (COPD), lung emphysema, and chronic wounding skin disease. Compositions and kits containing the peptide conjugates of the present invention find utility in a wide range of applications including, e.g., in vivo imaging and immunotherapy.

Hausner, Sven H.↗
DOE OSTI2023

Conductor on molded barrel magnet assembly and associated systems and methods

A Conductor on Molded Barrel (COMB) magnet assembly optimized for High Temperature Superconducting (HTS) materials. The magnet assembly comprises a magnetic coil(s) carried by a conductor support structure and configured in cosine-theta geometry. Created using additive manufacturing, the conductor support structure features a continuous cable channel that fittedly carries and positions elongated straight portion(s) of the magnetic coil(s) parallel to a magnetic axis. The conductor support structure may be cylindrically shaped and longitudinally bored, with the continuous cable channel comprising an outer channel portion (distal on the cylinder) and an inner channel portion (proximal on the cylinder). A transition hole that joins the outer channel portion and the inner channel portion allows a single magnetic coil to be wound along both the outer and inner surfaces of the conductor support structure. The conductor support structure may be fabricated as longitudinally-symmetrical halves, and secured for operation using azimuthal and/or midplane shims.

Kashikhin, Vadim V.↗
DOE OSTI2024

Method and apparatus for fabricating a hybrid tube

An apparatus for fabricating a hybrid tube includes a rotatable mandrel and a first housing configured to translate alongside the rotatable mandrel while dispensing a first strip to be helically wound about the mandrel. The first housing includes an angle adjustment mechanism to control a dispensation angle of the first strip. The apparatus also includes least one energy or adhesive source for bonding overlapping strip portions on the rotatable mandrel and forming the hybrid tube. The at least one energy or adhesive source is configured for translation alongside the rotatable mandrel.

Sinha, Sanjiv↗
DOE OSTI2024

Round superconductor wires

A round superconductor wire and method for fabricating same are disclosed. Embodiments are directed to a round superconductor wire including at least two superconductor tapes wound on a wire former. Each superconductor tape includes: bottom stabilizer and silver layers; substrate disposed above the bottom silver layer; buffer film stack disposed above the substrate; superconductor film disposed above the buffer film stack; top silver layer disposed above the superconductor film; and top stabilizer layer disposed above the top silver layer. At least one of the bottom stabilizer layer, bottom silver layer, substrate, buffer film stack, superconductor film, top silver layer, or top stabilizer layer is of a different width, thickness, or material composition in one of the superconductor tapes than in another of the superconductor tapes. These and other embodiments achieve a round superconductor wire having improved current density in high magnetic field applications when made in small diameters.

Majkic, Goran↗
DOE OSTI2024

Hemorrhage management system

An embodiment includes a wound dressing comprising: a shape memory polymer (SMP) foam, including open cells, having first and second states; and a hydrogel (HG) included within the cells; wherein (a) in a first position a composite, including the SMP foam and the HG, is configured to be located proximate a hemorrhagic tissue with the SMP foam in the first state; (b) in a second position the composite is configured to be expanded to the second state against the hemorrhagic tissue when the SMP foam is plasticized at 37° C. depressing a glass transition temperature (Tg) of the SMP foam to below 25° C. Other embodiments are described herein.

Maitland, Duncan J.↗
DOE OSTI2024

Transformer with integral inductor

In accordance with one embodiment is a transformer with a core comprising a perimeter portion and central intervening portion. The central intervening portion is separated from the perimeter portion by air gaps, creating an opening on either side of the intervening portion. A primary winding and secondary winding are wound around the central intervening portion of the core. The primary winding is capable of electromagnetic interaction with the secondary winding. A pair of ferrite members arranged outward from a central axis of the central intervening portion of the core and increases a series inductance with the primary winding. In accordance with another aspect of the disclosure, each ferrite member may have an air gap associated with the core to facilitate heat dissipation from the transformer.

Rastogi, Sagar K.↗
DOE OSTI2021

Vascular endothelial and smooth muscle cell galvanotactic response and differential migratory behavior

Chronic disease or injury of the vasculature impairs the functionality of vascular wall cells particularly in their ability to migrate and repair vascular surfaces. Under pathologic conditions, vascular endothelial cells (ECs) lose their non-thrombogenic properties and decrease their motility. Alternatively, vascular smooth muscle cells (SMCs) may increase motility and proliferation, leading to blood vessel luminal invasion. Current therapies to prevent subsequent blood vessel occlusion commonly mechanically injure vascular cells leading to endothelial denudation and smooth muscle cell luminal migration. Due to this dichotomous migratory behavior, a need exists for modulating vascular cell growth and migration in a more targeted manner. Here, we examine the efficacy of utilizing small direct current electric fields to influence vascular cell-specific migration (“galvanotaxis”). We designed, fabricated, and implemented an in vitro chamber for tracking vascular cell migration direction, distance, and displacement under galvanotactic influence of varying magnitude. Our results indicate that vascular ECs and SMCs have differing responses to galvanotaxis; ECs exhibit a positive correlation of anodal migration while SMCs exhibit minimal change in directional migration in relation to the electric field direction. SMCs exhibit less motility response (i.e. distance traveled in 4 h) compared to ECs, but SMCs show a significantly higher motility at low electric potentials (80 mV/cm). With further investigation and translation, galvanotaxis may be an effective solution for modulation of vascular cell-specific migration, leading to enhanced endothelialization, with coordinate reduced smooth muscle in-migration.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Activation of the plant mevalonate pathway by extracellular ATP

The mevalonate pathway plays a critical role in multiple cellular processes in both animals and plants. In plants, the products of this pathway impact growth and development, as well as the response to environmental stress. A forward genetic screen of Arabidopsis thaliana using Ca 2+ -imaging identified mevalonate kinase (MVK) as a critical component of plant purinergic signaling. MVK interacts directly with the plant extracellular ATP (eATP) receptor P2K1 and is phosphorylated by P2K1 in response to eATP. Mutation of P2K1-mediated phosphorylation sites in MVK eliminates the ATP-induced cytoplasmic calcium response, MVK enzymatic activity, and suppresses pathogen defense. The data demonstrate that the plasma membrane associated P2K1 directly impacts plant cellular metabolism by phosphorylation of MVK, a key enzyme in the mevalonate pathway. The results underline the importance of purinergic signaling in plants and the ability of eATP to influence the activity of a key metabolite pathway with global effects on plant metabolism.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Comparison of Candidate Designs and Performance Optimization for an Electric Traction Motor Targeting 50 kW/L Power Density

The continued expansion of the global electric vehicle fleet is accompanied by an unprecedented demand for high power density electric traction motors. With the ambitious U.S. DRIVE 2025 target of 50 kW/L power density and an equally aggressive cost reduction goal, innovative approaches have to be utilized in terms of both the design and manufacturing of electric traction motors. In this paper, six motor options are compared and the best design is picked for each option to investigate the drive and excitation requirements and the weighted power efficiency over multiple load points, with necessary mechanical stress and demagnetization checks. State-of-the-art winding technologies, including high slot fill die compressed windings and hairpin windings, and rotors both with permanent magnet (PM) and PM-free are incorporated. The design of high flux density and low harmonic content magnetic field is also demonstrated.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2023

Electrospun PVA Fibers for Drug Delivery: A Review

Innovation in biomedical science is always a field of interest for researchers. Drug delivery, being one of the key areas of biomedical science, has gained considerable significance. The utilization of simple yet effective techniques such as electrospinning has undergone significant development in the field of drug delivery. Various polymers such as PEG (polyethylene glycol), PLGA (Poly(lactic-co-glycolic acid)), PLA(Polylactic acid), and PCA (poly(methacrylate citric acid)) have been utilized to prepare electrospinning-based drug delivery systems (DDSs). Polyvinyl alcohol (PVA) has recently gained attention because of its biocompatibility, biodegradability, non-toxicity, and ideal mechanical properties as these are the key factors in developing DDSs. Moreover, it has shown promising results in developing DDSs individually and when combined with natural and synthetic polymers such as chitosan and polycaprolactone (PCL). Considering the outstanding properties of PVA, the aim of this review paper was therefore to summarize these recent advances by highlighting the potential of electrospun PVA for drug delivery systems.

59 BASIC BIOLOGICAL SCIENCES↗