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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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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A Review of the Use of Wearables in Indoor Environmental Quality Studies and an Evaluation of Data Accessibility from a Wearable Device

An understanding of indoor environmental quality (IEQ) and its effects on occupant well-being can inform building system design and operation. The use of wearables in field studies to collect subjective and objective health performance indicators (HPIs) from a large number of occupants could deliver important improvements in IEQ. To facilitate the use of wearables in IEQ studies, there is a need to identify which HPIs should be collected and to evaluate data accessibility from these devices. To address this issue, a literature review of previous IEQ studies was conducted to identify relationships between different IEQ factors and HPIs, with a focus on HPIs that were collected using wearables. A preliminary assessment of data accessibility from a selected wearable device (Fitbit Versa 2) was performed and documented. The review suggested the need to further investigate and collect sleep quality parameters, heart rate, stress response, as well as subjective ratings of comfort using wearables. The data accessibility assessment revealed issues related to missing data points and data resolution from the examined device. A set of recommendations is outlined to inform future studies.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Developing affordable and efficient heating devices for enhanced live cell imaging in confocal microscopy

Temperature control is crucial for live cell imaging, particularly in studies involving plant responses to high ambient temperatures and thermal stress. This study presents the design, development, and testing of two cost-effective heating devices tailored for confocal microscopy applications: an aluminum heat plate and a wireless mini-heater. The aluminum heat plate, engineered to integrate seamlessly with the standard 160 mm × 110 mm microscope stage, supports temperatures up to 36°C, suitable for studies in the range of non-stressful warm temperatures (e.g., 25-27°C forArabidopsis thaliana) and moderate heat stress (e.g., 30-36°C forA. thaliana). We also developed a wireless mini-heater that offers rapid, precise heating directly at the sample slide, with a temperature increase rate over 30 times faster than the heat plate. The wireless heater effectively maintained target temperatures up to 50°C, ideal for investigating severe heat stress and heat shock responses in plants. Both devices performed well in controlled studies, including the real-time analysis of heat shock protein accumulation and stress granule formation inA. thaliana. Our designs are effective and affordable, with total construction costs lower than $300. This accessibility makes them particularly valuable for small laboratories with limited funding. Future improvements could include enhanced heat uniformity, humidity control to mitigate evaporation, and more robust thermal management to minimize focus drift during extended imaging sessions. These modifications would further solidify the utility of our heating devices in live cell imaging, offering researchers reliable, budget-friendly tools for exploring plant thermal biology.

Plant Sciences↗
DOE OSTI2023

Methods to Create Novel La 2- x Sr x CuO 4 Devices with Multiple Atomically Sharp Interfaces

We present methods to create devices that utilize the high-temperature superconductor La 2-x Sr x CuO 4 grown by atomic layer-by-layer molecular beam epitaxy (ALL-MBE). The ALL-MBE synthesis technique provides atomically precise interfaces necessary for the tunnel junctions, Josephson junctions, and dyon detection devices that will be considered. A series of microfabrication processing steps using established techniques are given for each device, and their details are discussed. These procedures are easily extended to generate more complex designs and could be suitable for a wider variety of materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Smartphone-Based Device for Colorimetric Detection of MicroRNA Biomarkers Using Nanoparticle-Based Assay

The detection of microRNAs (miRNAs) is emerging as a clinically important tool for the non-invasive detection of a wide variety of diseases ranging from cancers and cardiovascular illnesses to infectious diseases. Over the years, miRNA detection schemes have become accessible to clinicians, but they still require sophisticated and bulky laboratory equipment and trained personnel to operate. The exceptional computing ability and ease of use of modern smartphones coupled with fieldable optical detection technologies can provide a useful and portable alternative to these laboratory systems. Herein, we present the development of a smartphone-based device called Krometriks, which is capable of simple and rapid colorimetric detection of microRNA (miRNAs) using a nanoparticle-based assay. The device consists of a smartphone, a 3D printed accessory, and a custom-built dedicated mobile app. We illustrate the utility of Krometriks for the detection of an important miRNA disease biomarker, miR-21, using a nanoplasmonics-based assay developed by our group. We show that Krometriks can detect miRNA down to nanomolar concentrations with detection results comparable to a laboratory-based benchtop spectrophotometer. With slight changes to the accessory design, Krometriks can be made compatible with different types of smartphone models and specifications. Thus, the Krometriks device offers a practical colorimetric platform that has the potential to provide accessible and affordable miRNA diagnostics for point-of-care and field applications in low-resource settings.

Krishnan, Tushar (ORCID:0000000342610336)↗
DOE OSTI2026

Nickel Interlayer for Improved Silver Complex Inks Metallization in GaAs Photovoltaic Devices

Large areas of III-V photovoltaic panels are essential to supplying operational energy for a growing demand of satellites of strategic importance to the United States military, covering a range of applications. High fabrication costs and low manufacturing throughput are key barriers to meeting the necessary supply, which can in turn jeopardize mission success. At the device level, metallization based on printing of complex metal inks has attracted significant research interest due to its potential to substantially reduce processing costs and increase throughput while achieving electrical performance comparable to those of conventional metallization schemes. For GaAs photovoltaic devices, however, reliable electrical contacting remains challenging due to the formation of an interfacial oxide layer at the metal-semiconductor interface. This oxide barrier severely limits current extraction from the PV absorber, resulting in unacceptably high contact resistance. In this study, we report the introduction of a reactive nickel (Ni) interfacial layer between the silver metal fingers and the GaAs substrate to suppress oxide formation while maintaining a low-resistance electrical interface, and show performance data from fully fabricated GaAs devices incorporating the Ni interlayer. These results demonstrate the potential of reactive Ni ink as an effective interfacial layer for improved electrical contacting in low-cost PV metallization schemes.

14 SOLAR ENERGY↗
DOE OSTI2026

A Relief Zone Architecture for Enhanced Durability of Ultrathin Membranes in Electrochemical Conversion Devices

Premature cell failures in electrochemical conversion systems often result when membrane electrode assemblies (MEAs) are prepared with ultra-thin (= 15 micrometer-thick) polymer electrolyte membranes (PEMs). These high-performance PEMs are susceptible to mechanical degradation from stress concentrations arising from component and device-level integration. Herein, a relief zone was developed to mitigate mechanical degradation by alleviating excess and non-uniform compression across the active area. Relief zones, created through the ablation of carbonaceous diffusion material achieves a seamless adaptation across a range of MEA dimensions and electrochemical applications without need for costly hardware modifications. This concept was demonstrated using fuel cells as a case study. Accelerated stress test (AST) validations yielded a 6-fold improvement for MEAs prepared with relief zones (i.e., lifetime approximately 1500 h) compared to those fabricated using conventional edge-protection techniques, showcasing the utility of this technique in decoupling integration and device-level engineering effects from intrinsic material limitations for durable electrochemical devices.

14 SOLAR ENERGY↗
DOE OSTI2021

Multi-device Studies of Pedestal Physics and Confinement in the I-mode Regime

This paper describes joint ITPA studies of the I-mode regime, which features an edge thermal barrier but with L-mode-like particle and impurity transport, and without ELMs. The regime has been demonstrated on Alcator C-Mod, ASDEX Upgrade and DIII-D tokamaks, over a wide range of device parameters and pedestal conditions, including low collisionality. Access to I-mode is independent of heating method (neutral beam injection, ICRH and/or ECRH). Normalized energy confinement H98y,2 ≥ 1 has been achieved for a range of 3≤q95≤4.9 and scales favourably with power. Changes in turbulence in the pedestal region accompany the transition from L-mode to I-mode. The L-I threshold increases with plasma density and current, and with device size, but weakly with BT. The upper limit of power for I-modes increases with toroidal field, and is largest on Alcator C-Mod at B > 5 T. Issues for extrapolation to ITER and other future fusion devices are discussed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Metamaterial-Inspired Vacuum Electron Devices and Accelerators

Metamaterials (MTMs) are structured materials with subwavelength features that can be engineered to have some unique properties not found in nature, such as negative refractive index, reversed Doppler effect, and reversed Cherenkov radiation. Based on these novel MTMs, several important research groups have made great attempts to develop novel MTM-inspired vacuum electron devices (VEDs) and accelerators. Just as solid-state power devices are innovated by incessant emerging of new semiconductor materials, VEDs can also be inspired by MTMs to have very remarkable advantages, such as smaller size, higher power, higher efficiency, and/or larger gain relative to conventional VEDs, such as traveling-wave tubes, backward-wave oscillators, and klystrons. Similarly, relative to conventional accelerators, MTM-inspired accelerators have obvious advantages, such as smaller size and higher accelerating gradient. Furthermore, MTM-inspired devices have promising applications in areas such as radar, communication, electronic warfare, microwave heating, and imaging.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Devices and methods for removing dissolved ions from water using composite resin electrodes

The present invention provides for a device useful or removing dissolved ions from water comprising or configured to comprise composite resin electrodes. The present invention provides for a device useful for removing dissolved ions from water comprising or configured to comprise composite resin electrodes. The present invention also provides for a method for removing dissolved ions from water comprising providing said device, and using it thereof.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Group-III nitride devices and systems on IBAD-textured substrates

A multilayer structure including a hexagonal epitaxial layer, such as GaN or other group III-nitride (III-N) semiconductors, a <111> oriented textured layer, and a non-single crystal substrate, and methods for making the same. The textured layer has a crystalline alignment preferably formed by the ion-beam assisted deposition (IBAD) texturing process and can be biaxially aligned. The in-plane crystalline texture of the textured layer is sufficiently low to allow growth of high quality hexagonal material, but can still be significantly greater than the required in-plane crystalline texture of the hexagonal material. The IBAD process enables low-cost, large-area, flexible metal foil substrates to be used as potential alternatives to single-crystal sapphire and silicon for manufacture of electronic devices, enabling scaled-up roll-to-roll, sheet-to-sheet, or similar fabrication processes to be used. The user is able to choose a substrate for its mechanical and thermal properties, such as how well its coefficient of thermal expansion matches that of the hexagonal epitaxial layer, while choosing a textured layer that more closely lattice matches that layer. Electronic devices such as LEDs can be manufactured from such structures. Because the substrate can act as both a reflector and a heat sink, transfer to other substrates, and use of external reflectors and heat sinks, is not required, greatly reducing costs. Large area devices such as light emitting strips or sheets may be fabricated using this technology.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Sound-masking device for a roll-up door

A portable sound-masking device for placing on a roll-up door having a number of horizontally-extending elements. The sound-masking device has a fixture, a magnet, and a transducer. The fixture has an inner face, an outer face, and a pair of spaced-apart tabs protruding from the inner face, the tabs being configured to engage one of the horizontally-extending elements of the roll-up door. The magnet is fastened to the inner face of the fixture and provides a force that tethers the sound-masking device to the roll-up door. The transducer is fastened to the outer face and is configured to emit sound-masking noise.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

Energy storage devices having coated passive components

The present invention provides various passive electronic components comprising a layer of coated particles, and methods for producing and using the same. Some of the passive electronic components of the invention include, but are not limited to conductors, resistors, current collectors, capacitors, piezoelectronic devices, inductors and transformers. The present invention also provides energy storage devices and electrode layers for such energy storage devices having passive, electrically-conductive particles coated with one or more thin film materials.

25 ENERGY STORAGE↗
DOE OSTI2020

Thermoelectric materials based on tetrahedrite structure for thermoelectric devices

Thermoelectric materials based on tetrahedrite structures for thermoelectric devices and methods for producing thermoelectric materials and devices are disclosed. The thermoelectric device has a pair of conductors and a p-type thermoelectric material disposed between the conductors. The thermoelectric material is at least partially formed of a hot pressed high energy milled tetrahedrite formed of tetrahedrite ore and pure elements to form a tetrahedrite powder of Cu12-xMxSb4S13 disposed between the conductors, where M is at least one of Zn and Fe.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Grid regulation services for energy storage devices based on grid frequency

Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Solid-state organic intermediate-band photovoltaic devices

In one aspect, solid-state organic intermediate-band photovoltaic devices are provided. A solid-state organic intermediate-band photovoltaic device, in some embodiments, comprises an organic electron donor and an organic electron acceptor, wherein the organic electron donor comprises a singlet energy level separated from a triplet energy level by an energy gap. The device also comprises a triplet sensitizer comprising singlet and triplet energy levels falling within the singlet-triplet energy gap of the electron donor.

14 SOLAR ENERGY↗
DOE OSTI2020

Discrete time analog front end circuit implemented in a receiver device

A device can comprise a peaked integrator circuit that generates an output signal from a continuous time signal based on a sub rate clock timing cycle. The device can further comprise a track and hold circuit coupled to the output of the peaked integrator that generates a held discrete time signal from the output of the peaked integrator based on a second sub rate clock timing cycle that is offset in time from the sub rate clock timing cycle by a single time unit interval. The device can further comprise an integrator circuit coupled to an output of the track and hold circuit that integrates the held discrete time signal, based on the second sub rate clock timing cycle that is offset in time from the sub rate clock timing cycle by a single time unit interval.

42 ENGINEERING↗
DOE OSTI2020

Communication device for implementing selective encryption in a software defined network

The present disclosure pertains to systems and methods for selectively encrypting data flows within a software defined network (SDN). In one embodiment, a communication device may be configured to receive a plurality of unencrypted data packets. The communication device may receive from an SDN controller a criterion used to identify at least one of the unencrypted data flows to be encrypted. Based on the criterion, an encryption subsystem may generate an encrypted data flow the unencrypted data packets based on an encryption key. In some embodiments, the encryption system may parse the packets and encrypt the data payloads without encrypting the routing information associated with the packet. In other embodiments, the encryption subsystem may be configured to encapsulate and encrypt the entire unencrypted data packet. In some embodiments, the encryption subsystem may further be configured to authenticate a sending device and/or to verify the integrity of a message.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Reversibly bonded devices and methods of making and using the same

The present disclosure concerns embodiments of reversibly bonded devices that comprise a reversible bonding component. The reversible bonding component is able to exhibit strong adhesive properties so as to couple device components, but upon exposure to an energy source, the strong adhesive properties are weakened. By weakening the adhesive strength of the reversible bonding component, the device can be deconstructed to access internal biological samples for analysis and characterization.

42 ENGINEERING↗