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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 217 records · Page 12

Heating system with induction power supply and electromagnetic acoustic transducer with induction power supply

A system for heating a fluid and an electromagnetic acoustic transducer EMAT system is provided. Both systems have a drive circuit. The amount of heat and the amplitude (and acceleration) of the vibrations is respectively controllable by controlling an input to a terminal of a switch. The heating system comprises a porous graphite foam conductor which is exposed to an electromagnetic field generated by an oscillating circuit. When exposed, the foam conductor conducts induced electric current which heats the same and a fluid in contact with the conductor. The EMAT system comprises at least one magnet configured to generate a static magnetic field, an oscillating circuit and a working element. The working element, when exposed to the static magnetic field and the electromagnetic field produced by the oscillating circuit, vibrates against a load. The vibrations dry the load.

Kisner, Roger A.↗

Multilayered Cu-Carbon Nanotube Composites for Advanced Conductors

Improving the efficiency of electrical components is critical in reducing energy consumption for various industrial and residential applications, ranging from rotating machinery to all electric devices and electric vehicle (EV) components to power grid systems. Substituting Cu wires with reduced resistance conductors that incorporate carbon nanotubes (CNTs) into Cu─ultraconductive Cu (UCC) composites─has recently been considered a promising strategy to improve energy efficiency, power density, and/or performance across various applications. Here, in this study, we created stable material formulations [CNT-containing polyvinylpyrrolidone (PVP) in dimethylformamide (DMF) solution] and utilized commercially viable fabrication approaches (electrospinning and magnetron sputtering) that produced high-performance multilayered tape-based UCC composite architectures. Increasing the CNT volume fraction by sequential layering of the structure with additional Cu-CNT layers showed a nearly stepwise improved performance in electrical and mechanical properties. This study also provides valuable insight into the effectiveness of nitrogen doping in modifying the conductivity of the CNT matrix. Fabricated prototypes demonstrated a >10% increase in current carrying capacity and >10% improvement in mechanical strength compared to those obtained on pure Cu. We believe that the properties demonstrated here, combined with the scalable manufacturing pathway of our approach, pave the way in designing future advanced conductors for diverse energy efficient and high-performance electrical systems and applications.

Carbon nanotubes↗

Physical and Electronic Isolation of Carbon Nanotube Conductors

Multi-walled nanotubes are proposed as a method to electrically and physically isolate nanoscale conductors from their surroundings. We use tight binding (TB) and density functional theory (DFT) to simulate the effects of an external electric field on multi-wall nanotubes. Two categories of multi-wall nanotube are investigated, those with metallic and semiconducting outer shells. In the metallic case, simulations show that the outer wall effectively screens the inner core from an applied electric field. This offers the ability to reduce crosstalk between nanotube conductors. A semiconducting outer shell is found not to perturb an electric field incident on the inner core, thereby providing physical isolation while allowing the tube to remain electrically coupled to its surroundings.

OKeeffe, James↗

Cost-effective Conductor, Cable, and Coils for High Field Rotating Electric Machines

The purpose of the DOE-AMMTO-funded project was to significantly reduce industrial energy intensity through manufacturing innovations. The project focused on superconducting technology for industrial motors to dramatically increase efficiency. The bottleneck in deploying high temperature superconducting (HTS) motors was high cost and low yield of the conductor manufacturing process. The process yield is low because of the defects in the conductor, forcing the manufacturers to cut off defective sections after characterizing each millimeter. Additionally, the piece lengths tend to be low because of the defects. The project tackled the low-yield manufacturing process challenge by devising an innovative method to use defective conductors in bundled cables without losing performance by engineering current sharing among the conductors. The innovation not only lowers the cost of the conductor but also enhances the reliability of HTS motors and other devices to mitigate the defects that might form during the fabrication and operation of the device. With the increasing interest in REBa2Cu3O7-x (REBCO)-coated conductors for various power, energy, and magnet applications, ensuring the reliability of HTS devices is of significant interest. The EERE funding allowed us to make significant progress in understanding the defects in manufactured conductors and the implications of the defects in superconducting electric motors and other superconducting power and energy applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Copper–Carbon Nanotube Composites Enabled by Brush Coating for Advanced Conductors

There is a growing demand for advanced conductors with enhanced electrical properties to increase the energy efficiency in various applications. A promising strategy to achieve this involves the use of ultraconductive copper (UCC) composites that incorporate highly conductive carbon materials, such as carbon nanotubes (CNTs), into the copper matrix. In this study, we present a scalable brush coating technique to incorporate CNTs onto Cu substrates to produce Cu–CNT–Cu composites. The process involves brush coating the CNT solution on Cu tape substrates, followed by vacuum-assisted thermal removal of organic moieties (e.g., surfactant/polymer). This step ensures the creation of a uniformly distributed CNT network within the Cu matrix. By addition of a thin film Cu overlayer, the fabricated Cu–CNT–Cu composite architecture demonstrates similar electrical conductivity, increased current carrying capacity, and enhanced mechanical properties compared to pure Cu reference tapes. Finally, the performance characteristics of these UCC tapes along with the scalability of the brush coating approach hold great promise for the fabrication of advanced conductors for wide-ranging energy applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Experimental studies and applications of vanadium oxides.

The electrical and electrochemical properties of V-5 and V-7 vanadium oxides were investigated. The effects of pressure, temperature and moisture on the bulk resistivity of the oxides in powder, sintered, and crystalline form were determined, and the static and dynamic volt-ampere characteristics were obtained. Sintered samples tested showed better electrical stability than the compressed powder samples. Two types of commercially available vanadium pentoxide were heat-treated to obtain various crystalline oxide forms which were mounted on alumina substrates and terminated by thick-film conductors for making electrical connections. Indications are that these materials could have applications as sensors, critical-temperature resistors, high-speed switches, and temperature-compensation elements in hybrid microelectronic circuits.

Williams, L., Jr.↗

Methods and devices for non-invasive root phenotyping

The present disclosure provides for an electronic sensor for detecting a root of a plant in soil, the electronic sensor that includes a first conductor plate configured to be disposed in soil, a switch, a power supply, and signal extractor. The switch is electrically coupled to the first conductor plate and is configured to switch between a first mode and a second mode. The power supply is electrically coupled to the switch and is configured to provide an electrical charge to the first conductor plate in the first mode of the switch. The signal extractor is electrically coupled to the switch and is configured to extract a signal response at the first conductor plate in the second mode of the switch. The present disclosure further provides a second conductor plate configured to be disposed in soil adjacent to and substantially parallel to the first conductor plate. The second conductor plate is electrically coupled to ground.

47 OTHER INSTRUMENTATION↗

Methods and devices for non-invasive root phenotyping

The present disclosure provides for an electronic sensor for detecting a root of a plant in soil, the electronic sensor that includes a first conductor plate configured to be disposed in soil, a switch, a power supply, and signal extractor. The switch is electrically coupled to the first conductor plate and is configured to switch between a first mode and a second mode. The power supply is electrically coupled to the switch and is configured to provide an electrical charge to the first conductor plate in the first mode of the switch. The signal extractor is electrically coupled to the switch and is configured to extract a signal response at the first conductor plate in the second mode of the switch. The present disclosure further provides a second conductor plate configured to be disposed in soil adjacent to and substantially parallel to the first conductor plate. The second conductor plate is electrically coupled to ground.

Benfey, Philip N.↗

Methods and devices for non-invasive root phenotyping

The present disclosure provides for an electronic sensor for detecting a root of a plant in soil, the electronic sensor that includes a first conductor plate configured to be disposed in soil, a switch, a power supply, and a signal extractor. The switch is electrically coupled to the first conductor plate and is configured to switch between a first mode and a second mode. The power supply is electrically coupled to the switch and is configured to provide an electrical charge to the first conductor plate in the first mode of the switch. The signal extractor is electrically coupled to the switch and is configured to extract a signal response at the first conductor plate in the second mode of the switch. The present disclosure further provides a second conductor plate configured to be disposed in soil adjacent to and substantially parallel to the first conductor plate. The second conductor plate is electrically coupled to ground.

Benfey, Philip↗

Coaxial Electric Heaters

Coaxial electric heaters have been conceived for use in highly sensitive instruments in which there are requirements for compact heaters but stray magnetic fields associated with heater electric currents would adversely affect operation. Such instruments include atomic clocks and magnetometers that utilize heated atomic-sample cells, wherein stray magnetic fields at picotesla levels could introduce systematic errors into instrument readings. A coaxial electric heater is essentially an axisymmetric coaxial cable, the outer conductor of which is deliberately made highly electrically resistive so that it can serve as a heating element. As in the cases of other axisymmetric coaxial cables, the equal magnitude electric currents flowing in opposite directions along the inner and outer conductors give rise to zero net magnetic field outside the outer conductor. Hence, a coaxial electric heater can be placed near an atomic-sample cell or other sensitive device. A coaxial electric heater can be fabricated from an insulated copper wire, the copper core of which serves as the inner conductor. For example, in one approach, the insulated wire is dipped in a colloidal graphite emulsion, then the emulsion-coated wire is dried to form a thin, uniform, highly electrically resistive film that serves as the outer conductor. Then the film is coated with a protective layer of high-temperature epoxy except at the end to be electrically connected to the power supply. Next, the insulation is stripped from the wire at that end. Finally, electrical leads from the heater power supply are attached to the exposed portions of the wire and the resistive film. The resistance of the graphite film can be tailored via its thickness. Alternatively, the film can be made from an electrically conductive paint, other than a colloidal graphite emulsion, chosen to impart the desired resistance. Yet another alternative is to tailor the resistance of a graphite film by exploiting the fact that its resistance can be changed permanently within about 10 percent by heating it to a temperature above 300 C. A coaxial heater, with electrical leads attached, that has been bent into an almost full circle for edge heating of a circular window is shown. (In the specific application, there is a requirement for a heated cell window, through which an optical beam enters the cell.)

Strekalov, Dmitry↗

CABLE Big Idea RDD&D Workshop (Workshop Summary Report)

The U.S. Department of Energy’s (DOE’s) Advanced Manufacturing Office (AMO) held the CABLE Big Idea RDD&D Workshop April 7–9, 2021. The virtual workshop brought together approximately 250 leading scientific and technical experts to gather information on the state of the art in conductivity-enhanced materials and their applications. These stakeholders included scientists, engineers, manufacturers, materials experts, utility companies, and other entities within the conductor material and electrical product manufacturing supply chains. The two main goals of the workshop were to 1) start building and strengthening a research ecosystem around conductivity-enhanced materials and 2) inform AMO’s future portfolio of research, development, demonstration, and deployment (RDD&D) investments and other program activities in the area of conductivity-enhanced materials. CABLE—or Conductivity-enhanced materials for Affordable, Breakthrough Leapfrog Electric and thermal applications—was was established as an Office of Energy Efficiency and Renewable Energy initiative as a result of a competitive internal process to identify and prioritize potentially high-impact research topics. Since then, conductivity-enhanced materials have been identified as an important element of the shift to an electrified and decarbonized industry sector, and CABLE remains a Big Idea. The CABLE effort is led by AMO and supported by eight other offices within DOE. The first major effort under CABLE was the development of several subtopics for DOE’s Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) programs in 2020. Another major activity was the launch of the CABLE Conductor Manufacturing Prize in March 2021.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Novel Processing, Testing and Characterization of Copper/Carbon Nanotube (Cu/CNT) Yarn Composite Conductor

Sustainable electrified aircraft propulsion (EAP) is likely to lead to an increase in the electrical wiring contained within a single aircraft. Since the electrical resistance and mass of copper (Cu) conductors are associated with power losses, it is desirable to design high-conductivity lightweight conductor materials, thus reducing the mass of components like motor windings, low-voltage signal cables, and transmission cables for data and power to improve the overall energy efficiency. This paper describes a unique framework for manufacturing metalized carbon nanotube (CNT) composite conductors, measuring their electrical conductivity and strength, and modeling the overall conductivity and current sharing within such composites. Tensile testing was conducted on the processed composite conductor cables with the use of acoustic emission and electrical resistivity to determine stress-dependent-failure mechanisms while monitoring the electrical conductivity. The average of measured electrical conductivities of annealed Cu/CNT samples from batch 5 was greater than theoretical predictions by 9.8 percent and was also greater than the conductivity of pure annealed Cu by 4.8 percent and had comparable ultimate tensile strengths. Additionally, those Cu/CNT samples provide a 13.5% weight saving over current state of the art copper wires. Theories explaining improved intrinsic conductivity are discussed.

Metalized CNT↗

Downhole to surface communications platform for drilling applications

A drilling assembly for downhole to surface communications is provided. The drilling assembly includes a series of pipe segments coupled in fluid communication between a slip ring assembly and an end pipe portion. The slip ring assembly is coupled in data and fluid communication with the pipe segments. A surface communications link is in data communication with the drilling assembly via the slip ring assembly. An end pipe portion is coupled with the drilling assembly that includes an electronics assembly with electronic components for transferring data to the slip ring assembly via the drilling assembly. A drill bit is operably coupled with the end pipe portion for drilling a borehole. Each pipe segment includes an outer conductor portion, a hollow inner conductor portion, and a dielectric portion for electrical isolation between the outer conductor portion and the inner conductor portion.

Su, Jiann-Cherng↗

Isentropic compression of fused quartz and liquid hydrogen to several Mbar

Models of the major planets are in part based on the equations of state of very compressible materials such as hydrogen and helium. A technique of isentropically compressing soft material to several Mbar and some preliminary results on fused quartz (silicon dioxide) and liquid hydrogen is described. Quartz was found to be an electrical non-conductor up to 5 Mbar and has a volume of about 0.15 cubic centimeters per gram at that pressure. Liquid hydrogen was found to have a volume of about 1 cm3/g at a pressure of about 2 Mbar. It was not determined if it was transformed into a metal.

Hawke, R. S.↗

Galileo internal electrostatic discharge program

The Galileo spacecraft which will orbit Jupiter in 1988 will encounter a very harsh environment of energetic electrons. These electrons will have sufficient energy to penetrate the spacecraft shielding, consequently depositing charges in the dielectric insulating materials or ungrounded conductors. The resulting electric field could exceed the breakdown strength of the insulating materials, producing discharges. The transients produced from these Internal Electrostatic Discharges (IESD) could, depending on their relative location, be coupled to nearby cables and circuits. These transients could change the state of logic circuits or degrade or even damage spacecraft components, consequently disrupting the operation of subsystems and systems of the Galileo spacecraft during its expected mission life. An extensive testing program was initiated for the purpose of understanding the potential threats associated with these IESD events. Data obtained from these tests were used to define design guidelines.

Leung, P. L.↗