Enabling lunar and space missions by laser power transmission

NASA Technical Reports Server (NTRS)

Deyoung, R. J.; Nealy, J. E.; Humes, D. H.; Meador, W. E.

1992-01-01

Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions.

Study of Carbon Nanotubes as Etching Masks and Related Applications in the Surface Modification of GaAs-based Light-Emitting Diodes.

PubMed

Jin, Yuanhao; Li, Qunqing; Chen, Mo; Li, Guanhong; Zhao, Yudan; Xiao, Xiaoyang; Wang, Jiaping; Jiang, Kaili; Fan, Shoushan

2015-09-02

The surface modification of LEDs based on GaAs is realized by super-aligned multiwalled carbon nanotube (SACNT) networks as etching masks. The surface morphology of SACNT networks is transferred to the GaAs. It is found that the light output power of LEDs based on GaAs with a nanostructured surface morphology is greatly enhanced with the electrical power unchanged. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reflectors with directional-mixed reflection properties for application in luminaries with high-power LED diodes

NASA Astrophysics Data System (ADS)

Zaremba, Krzysztof

2008-06-01

Application of directional-mixed reflectors results in a luminance decrease of the apparent image of light emitting diodes (LEDs), which is advantageous as far as glare reduction is concerned. On the other hand, reflectors have a negative impact on luminous intensity curves of the luminaries. This work analyzes an impact of surfaces with directional-mixed reflection properties in a mirror reflector designed for a luminary equipped with high-power LEDs. We present an algorithm used to determine the shape of the reflector of the surface with small scattering, where the axis twist angle for a parabolic reflector varies in a predefined range and follows a power function.

Large aspheric optics for high-power, high-energy laser

NASA Astrophysics Data System (ADS)

Geyl, Roland; Houbre, Francois

2001-12-01

SAGEM, within its REOSC high performance optics product line, has developed through the years a specific knowledge in large plano, spherical and aspherical optics for high energy or high power laser. This paper is aimed to illustrate the application of aspheric optics for such laser application with several examples of increasing optical surface complexity.

Thin film application device and method for coating small aperture vacuum vessels

DOEpatents

Walters, Dean R; Este, Grantley O

2015-01-27

A device and method for coating an inside surface of a vessel is provided. In one embodiment, a coating device comprises a power supply and a diode in electrical communication with the power supply, wherein electrodes comprising the diode reside completely within the vessel. The method comprises reversibly sealing electrodes in a vessel, sputtering elemental metal or metal compound on the surface while maintaining the surface in a controlled atmosphere.

Industrial applications of high-average power high-peak power nanosecond pulse duration Nd:YAG lasers

NASA Astrophysics Data System (ADS)

Harrison, Paul M.; Ellwi, Samir

2009-02-01

Within the vast range of laser materials processing applications, every type of successful commercial laser has been driven by a major industrial process. For high average power, high peak power, nanosecond pulse duration Nd:YAG DPSS lasers, the enabling process is high speed surface engineering. This includes applications such as thin film patterning and selective coating removal in markets such as the flat panel displays (FPD), solar and automotive industries. Applications such as these tend to require working spots that have uniform intensity distribution using specific shapes and dimensions, so a range of innovative beam delivery systems have been developed that convert the gaussian beam shape produced by the laser into a range of rectangular and/or shaped spots, as required by demands of each project. In this paper the authors will discuss the key parameters of this type of laser and examine why they are important for high speed surface engineering projects, and how they affect the underlying laser-material interaction and the removal mechanism. Several case studies will be considered in the FPD and solar markets, exploring the close link between the application, the key laser characteristics and the beam delivery system that link these together.

Developing Low-Power Transceiver Technologies for In Situ Communication Applications

NASA Astrophysics Data System (ADS)

Lay, N.; Cheetham, C.; Mojaradi, H.; Neal, J.

2001-07-01

For future deep-space missions, significant reductions in the mass and power requirements for short-range telecommunication systems will be critical in enabling a wide variety of new mission concepts. These possibilities include penetrators, gliders, miniature rovers, balloons, and sensor networks. The recent development activity reported in this article has focused on the design of ultra-low-mass and -power transceiver systems and subsystems suitable for operation in a flight environment. Under these efforts, the basic functionality of the transceiver has been targeted towards a Mars microprobe communications scenario. However, the overall transceiver architecture is well suited to any short- or medium-range application where a remote probe will aperiodically communicate with a base station, possibly an orbiter, for the eventual purpose of relaying science information back to Earth. Additionally, elements of the radio architecture can be applied in situations involving surface-to-surface communications, thereby enabling different mission communications topologies. Through a system analysis of these channels, both the applicability and benefit of very low power communications will be quantitatively addressed.

Figure of merit studies of beam power concepts for advanced space exploration

NASA Technical Reports Server (NTRS)

Miller, Gabriel; Kadiramangalam, Murali N.

1990-01-01

Surface to surface, millimeter wavelength beam power systems for power transmission on the lunar base were investigated. Qualitative/quantitative analyses and technology assessment of 35, 110 and 140 GHz beam power systems were conducted. System characteristics including mass, stowage volume, cost and efficiency as a function of range and power level were calculated. A simple figure of merit analysis indicates that the 35 GHz system would be the preferred choice for lunar base applications, followed closely by the 110 GHz system. System parameters of a 35 GHz beam power system appropriate for power transmission on a recent lunar base concept studied by NASA-Johnson and the necessary deployment sequence are suggested.

Terrestrial Applications of Extreme Environment Stirling Space Power Systems

NASA Technical Reports Server (NTRS)

Dyson, Rodger. W.

2012-01-01

NASA has been developing power systems capable of long-term operation in extreme environments such as the surface of Venus. This technology can use any external heat source to efficiently provide electrical power and cooling; and it is designed to be extremely efficient and reliable for extended space missions. Terrestrial applications include: use in electric hybrid vehicles; distributed home co-generation/cooling; and quiet recreational vehicle power generation. This technology can reduce environmental emissions, petroleum consumption, and noise while eliminating maintenance and environmental damage from automotive fluids such as oil lubricants and air conditioning coolant. This report will provide an overview of this new technology and its applications.

Human Mars Surface Mission Nuclear Power Considerations

NASA Technical Reports Server (NTRS)

Rucker, Michelle A.

2018-01-01

A key decision facing Mars mission designers is how to power a crewed surface field station. Unlike the solar-powered Mars Exploration Rovers (MER) that could retreat to a very low power state during a Martian dust storm, human Mars surface missions are estimated to need at least 15 kilowatts of electrical (kWe) power simply to maintain critical life support and spacecraft functions. 'Hotel' loads alone for a pressurized crew rover approach two kWe; driving requires another five kWe-well beyond what the Curiosity rover’s Radioisotope Power System (RPS) was designed to deliver. Full operation of a four-crew Mars field station is estimated at about 40 kWe. Clearly, a crewed Mars field station will require a substantial and reliable power source, beyond the scale of robotic mission experience. This paper explores the applications for both fission and RPS nuclear options for Mars.

Effects Investigated of Ambient High-Temperature Exposure on Alumina-Titania High-Emittance Surfaces for Solar Dynamic Systems

NASA Technical Reports Server (NTRS)

deGroh, Kim K.; Smith, Daniela C.

1999-01-01

Solar-dynamic space power systems require durable, high-emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. An alumina-titania coating, which has been evaluated for solar-dynamic heat receiver canister applications, has been chosen for a PLR application (an electrical sink for excess power from the turboalternator/compressor) because of its demonstrated high emittance and high-temperature durability in vacuum. Under high vacuum conditions (+/- 10(exp -6) torr), the alumina-titania coating was found to be durable at temperatures of 1520 F (827 C) for approx. 2700 hours with no degradation in optical properties. This coating has been successfully applied to the 2-kW solar-dynamic ground test demonstrator at the NASA Lewis Research Center, to the 500 thermal-energy-storage containment canisters inside the heat receiver and to the PLR radiator. The solar-dynamic demonstrator has successfully operated for over 800 hours in Lewis large thermal/vacuum space environment facility, demonstrating the feasibility of solar-dynamic power generation for space applications.

Nonlinear Analysis of Surface EMG Time Series

NASA Astrophysics Data System (ADS)

Zurcher, Ulrich; Kaufman, Miron; Sung, Paul

2004-04-01

Applications of nonlinear analysis of surface electromyography time series of patients with and without low back pain are presented. Limitations of the standard methods based on the power spectrum are discussed.

Advanced Energy Conversion Technologies and Architectures for Earth and Beyond

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Fikes, John C.; Phillips, Dane J.; Laycock, Rustin L.; ONeill, Mark; Henley, Mark W.; Fork, Richard L.

2006-01-01

Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. There is a need to produce "proof-ofconcept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space surface sites. Space surface receiving sites of particular interest include the areas of permanent shadow near the moon s North and South poles, where WPT technologies could enable access to ice and other useful resources for human exploration. This paper discusses work addressing a promising approach to solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) applied to both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming system in a space solar power application. Near-term uses of this SLA-laser-SLA system may include terrestrial and space exploration in near Earth space. Later uses may include beamed power for bases or vehicles on Mars. Strategies for developing energy infrastructures in space which utilize this technology are presented. This dual use system produces electrical energy efficiently from either coherent light, such as from a highly coherent laser, or from conventional solar illumination. This allows, for example, supplementing solar energy with energy provided by highly coherent laser illumination during periods of low solar illumination or no illumination. This reduces the need for batteries and alternate sources of power. The capability of using laser illumination in a lowest order Gaussian laser mode provides means for transmitting power optically with maximum efficiency and precision over the long distances characteristic of space. A preliminary receiving system similar to that described here, has been produced and tested under solar and laser illumination. A summary of results is given.

The Principle and the Application of Self-cleaning Anti-pollution Coating in Power System

NASA Astrophysics Data System (ADS)

Zhao, Y. J.; Zhang, Z. B.; Liu, Y.; Wang, J. H.; Teng, J. L.; Wu, L. S.; Zhang, Y. L.

2017-11-01

The common problem existed in power system is analyzed in this paper. The main reason for the affection of the safe and stable operation to power equipment is flash-over caused by dirt and discharge. Using the self-cleaning anti-pollution coating in the power equipment surface is the key to solve the problem. In the work, the research progress and design principle about the self-cleaning anti-pollution coating was summarized. Furthermore, the preparation technology was also studied. Finally, the application prospect of hard self-cleaning anti-pollution coating in power system was forecast.

Space Environment Stability and Physical Properties of New Materials for Space Power and Commercial Applications

NASA Technical Reports Server (NTRS)

Hambourger, Paul D.

1997-01-01

To test and evaluate suitability of materials for use in space power systems and related space and commercial applications, and to achieve sufficient understanding of the mechanisms by which, the materials perform in their intended applications. Materials and proposed applications included but were not limited to: Improved anodes for lithium ion batteries, highly-transparent arc-proof solar array coatings, and improved surface materials for solar dynamic concentrators and receivers. Cooperation and interchange of data with industrial companies as appropriate.

High Power High Efficiency Diode Laser Stack for Processing

NASA Astrophysics Data System (ADS)

Gu, Yuanyuan; Lu, Hui; Fu, Yueming; Cui, Yan

2018-03-01

High-power diode lasers based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As diode laser is simple in structure, small size, longer life expectancy with the advantages of low prices, it is widely used in the industry processing, such as heat treating, welding, hardening, cladding and so on. Respectively, diode laser could make it possible to establish the practical application because of rectangular beam patterns which are suitable to make fine bead with less power. At this power level, it can have many important applications, such as surgery, welding of polymers, soldering, coatings and surface treatment of metals. But there are some applications, which require much higher power and brightness, e.g. hardening, key hole welding, cutting and metal welding. In addition, High power diode lasers in the military field also have important applications. So all developed countries have attached great importance to high-power diode laser system and its applications. This is mainly due their low performance. In this paper we will introduce the structure and the principle of the high power diode stack.

SP-100 nuclear space power systems with application to space commercialization

NASA Technical Reports Server (NTRS)

Smith, John M.

1988-01-01

The purpose of this paper is to familiarize the Space Commercialization Community with the status and characteristics of the SP-100 space nuclear power system. The program is a joint undertaking by the Department of Defense, the Department of Energy and NASA. The goal of the program is to develop, validate, and demonstrate the technology for space nuclear power systems in the range of 10 to 1000 kWe electric for use in the future civilian and military space missions. Also discussed are mission applications which are enhanced and/or enabled by SP-100 technology and how this technology compares to that of more familiar solar power systems. The mission applications include earth orbiting platforms and lunar/Mars surface power.

[Progress in the application of laser ablation ICP-MS to surface microanalysis in material science].

PubMed

Zhang, Yong; Jia, Yun-hai; Chen, Ji-wen; Shen, Xue-jing; Liu, Ying; Zhao, Leiz; Li, Dong-ling; Hang, Peng-cheng; Zhao, Zhen; Fan, Wan-lun; Wang, Hai-zhou

2014-08-01

In the present paper, apparatus and theory of surface analysis is introduced, and the progress in the application of laser ablation ICP-MS to microanalysis in ferrous, nonferrous and semiconductor field is reviewed in detail. Compared with traditional surface analytical tools, such as SEM/EDS (scanning electron microscopy/energy dispersive spectrum), EPMA (electron probe microanalysis analysis), AES (auger energy spectrum), etc. the advantage is little or no sample preparation, adjustable spatial resolution according to analytical demand, multi-element analysis and high sensitivity. It is now a powerful complementary method to traditional surface analytical tool. With the development of LA-ICP-MS technology maturing, more and more analytical workers will use this powerful tool in the future, and LA-ICP-MS will be a super star in elemental analysis field just like LIBS (Laser-induced breakdown spectroscopy).

SP-100 reactor with Brayton conversion for lunar surface applications

NASA Technical Reports Server (NTRS)

Mason, Lee S.; Rodriguez, Carlos D.; Mckissock, Barbara I.; Hanlon, James C.; Mansfield, Brian C.

1992-01-01

Examined here is the potential for integrating Brayton-cycle power conversion with the SP-100 reactor for lunar surface power system applications. Two designs were characterized and modeled. The first design integrates a 100-kWe SP-100 Brayton power system with a lunar lander. This system is intended to meet early lunar mission power needs while minimizing on-site installation requirements. Man-rated radiation protection is provided by an integral multilayer, cylindrical lithium hydride/tungsten (LiH/W) shield encircling the reactor vessel. Design emphasis is on ease of deployment, safety, and reliability, while utilizing relatively near-term technology. The second design combines Brayton conversion with the SP-100 reactor in a erectable 550-kWe powerplant concept intended to satisfy later-phase lunar base power requirements. This system capitalizes on experience gained from operating the initial 100-kWe module and incorporates some technology improvements. For this system, the reactor is emplaced in a lunar regolith excavation to provide man-rated shielding, and the Brayton engines and radiators are mounted on the lunar surface and extend radially from the central reactor. Design emphasis is on performance, safety, long life, and operational flexibility.

Improvements of high-power diode laser line generators open up new application fields

NASA Astrophysics Data System (ADS)

Meinschien, J.; Bayer, A.; Bruns, P.; Aschke, L.; Lissotschenko, V. N.

2009-02-01

Beam shaping improvements of line generators based on high power diode lasers lead to new application fields as hardening, annealing or cutting of various materials. Of special interest is the laser treatment of silicon. An overview of the wide variety of applications is presented with special emphasis of the relevance of unique laser beam parameters like power density and beam uniformity. Complementary to vision application and plastic processing, these new application markets become more and more important and can now be addressed by high power diode laser line generators. Herewith, a family of high power diode laser line generators is presented that covers this wide spectrum of application fields with very different requirements, including new applications as cutting of silicon or glass, as well as the beam shaping concepts behind it. A laser that generates a 5m long and 4mm wide homogeneous laser line is shown with peak intensities of 0.2W/cm2 for inspection of railway catenaries as well as a laser that generates a homogeneous intensity distribution of 60mm x 2mm size with peak intensities of 225W/cm2 for plastic processing. For the annealing of silicon surfaces, a laser was designed that generates an extraordinary uniform intensity distribution with residual inhomogeneities (contrast ratio) of less than 3% over a line length of 11mm and peak intensities of up to 75kW/cm2. Ultimately, a laser line is shown with a peak intensity of 250kW/cm2 used for cutting applications. Results of various application tests performed with the above mentioned lasers are discussed, particularly the surface treatment of silicon and the cutting of glass.

Hybrid Power Management (HPM)

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2007-01-01

The NASA Glenn Research Center s Avionics, Power and Communications Branch of the Engineering and Systems Division initiated the Hybrid Power Management (HPM) Program for the GRC Technology Transfer and Partnership Office. HPM is the innovative integration of diverse, state-of-the-art power devices in an optimal configuration for space and terrestrial applications. The appropriate application and control of the various power devices significantly improves overall system performance and efficiency. The advanced power devices include ultracapacitors and fuel cells. HPM has extremely wide potential. Applications include power generation, transportation systems, biotechnology systems, and space power systems. HPM has the potential to significantly alleviate global energy concerns, improve the environment, and stimulate the economy. One of the unique power devices being utilized by HPM for energy storage is the ultracapacitor. An ultracapacitor is an electrochemical energy storage device, which has extremely high volumetric capacitance energy due to high surface area electrodes, and very small electrode separation. Ultracapacitors are a reliable, long life, maintenance free, energy storage system. This flexible operating system can be applied to all power systems to significantly improve system efficiency, reliability, and performance. There are many existing and conceptual applications of HPM.

High Power Helicon Plasma Source for Plasma Processing

NASA Astrophysics Data System (ADS)

Prager, James; Ziemba, Timothy; Miller, Kenneth E.

2015-09-01

Eagle Harbor Technologies (EHT), Inc. is developing a high power helicon plasma source. The high power nature and pulsed neutral gas make this source unique compared to traditional helicon source. These properties produce a plasma flow along the magnetic field lines, and therefore allow the source to be decoupled from the reaction chamber. Neutral gas can be injected downstream, which allows for precision control of the ion-neutral ratio at the surface of the sample. Although operated at high power, the source has demonstrated very low impurity production. This source has applications to nanoparticle productions, surface modification, and ionized physical vapor deposition.

Applications of nuclear power to lunar and Mars missions

NASA Technical Reports Server (NTRS)

Friedlander, Alan; Cole, Kevin

1988-01-01

The initial elements of an ambitious program for human exploration beyond Earth have been developed and presented to NASA management for its consideration. The Outpost on the Moon and Humans to Mars are two key U.S. programs (Ride 1987). A major space goal of this magnitude can only be implemented by a series of program phases evolving from precursor robotic missions, to initial development of temporary surface stations and buildup of operational experience, through the eventual establishment of permanent and sustained surface bases. Each phase of the separate (or linked) lunar and Mars scenarios will require distinctly different levels and types of power sources to support both transportation and on-surface operations, i.e., the nuclear power reactor. Discussed are the respective types and specific amounts of power required for all major systems in a phased program of lunar and Mars exploration over the period 1990 to 2040. A comparative assessment of technology tradeoffs and special design problems is made to ascertain the most appropriate application for the different phases, as well as to identify synergistic developments across the programs.

Workshop III: Future Directions for Thin Films Workshop at SPRAT XIX

NASA Technical Reports Server (NTRS)

Dickman, John E.; McNatt, Jeremiah S.

2007-01-01

The SPRAT conference series at NASA Glenn Research Center has devoted a workshop to the topic of thin-film solar cell technology and potential aerospace applications. With the advent of aerospace applications requiring very-high, mass, specific power, there has been a renewed interest in thin film materials and solar cells. Aerospace applications such as station-keeping for high-altitude airships, space solar power, lunar and planetary surface power, and solar electric propulsion would be enhanced or enabled by the development of flexible, very-high, mass specific power thin film arrays. To initiate discussion, a series of questions were asked of the attendees. These questions, three generated by the group, and the attendees comments follow.

BIOGRASS EXTRA®

EPA Pesticide Factsheets

Technical product bulletin: this surface washing agent for oil spill cleanups can be applied by power spraying or direct application. For direct application, remove contaminated soil, sand, etc. into a container and agitate after irrigating with product.

A unified view of energetic efficiency in active drag reduction, thrust generation and self-propulsion through a loss coefficient with some applications

NASA Astrophysics Data System (ADS)

Arakeri, Jaywant H.; Shukla, Ratnesh K.

2013-08-01

An analysis of the energy budget for the general case of a body translating in a stationary fluid under the action of an external force is used to define a power loss coefficient. This universal definition of power loss coefficient gives a measure of the energy lost in the wake of the translating body and, in general, is applicable to a variety of flow configurations including active drag reduction, self-propulsion and thrust generation. The utility of the power loss coefficient is demonstrated on a model bluff body flow problem concerning a two-dimensional elliptical cylinder in a uniform cross-flow. The upper and lower boundaries of the elliptic cylinder undergo continuous motion due to a prescribed reflectionally symmetric constant tangential surface velocity. It is shown that a decrease in drag resulting from an increase in the strength of tangential surface velocity leads to an initial reduction and eventual rise in the power loss coefficient. A maximum in energetic efficiency is attained for a drag reducing tangential surface velocity which minimizes the power loss coefficient. The effect of the tangential surface velocity on drag reduction and self-propulsion of both bluff and streamlined bodies is explored through a variation in the thickness ratio (ratio of the minor and major axes) of the elliptical cylinders.

Application of Pyrometry and IR-Thermography to High Surface Temperature Measurements

DTIC Science & Technology

2000-04-01

infrared spectra. Pneumatic thermal detectors use the effect of pres- sure change in a gas chamber due to radiation The second group of quantum detectors ...application of photo conductive detectors is re- a good signal to noise ratio. Each detector has a stricted by the recombination noise due to the elec...tricity. The signal power equal to the noise power of the detector is called the noise equivalent power AE tAE (NEP). It strongly depends on the

Darrieus wind-turbine and pump performance for low-lift irrigation pumping

NASA Astrophysics Data System (ADS)

Hagen, L. J.; Sharif, M.

1981-10-01

In the Great Plains about 15 percent of the irrigation water pumped on farms comes from surface water sources; for the United States as a whole, the figure is about 22 percent. Because of forecast fuel shortages, there is a need to develop alternative energy sources such as wind power for surface water pumping. Specific objectives of this investigation were to: design and assemble a prototype wind powered pumping system for low lift irrigation pumping; determine performance of the prototype system; design and test an irrigation system using the wind powered prototype in a design and test an farm application; and determine the size combinations of wind turbines, tailwater pits, and temporary storage reservoirs needed for successful farm application of wind powered tailwater pumping systems in western Kansas. The power source selected was a two bladed, 6 m diameter, 9 m tall Darrieus vertical axis wind turbine with 0.10 solidity and 36.1 M(2) swept area.

Application of the MOS C-V technique to determine impurity concentrations and surface parameters on the diffused face of silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.

1975-01-01

An experimental and theoretical investigation of the feasibility of using the MOS C-V (capacitance-voltage) technique to determine impurity and surface state concentrations on the diffused face of Si solar cells with Ta2O5 coatings. Impurity concentration 10 A from the diffused surface is found to be 2.9 times 10 to the 20th power per cu cm. Charge density in surface and oxide states is 2.1 times 10 to the 13th power per sq cm. These data agree with theoretical predictions.-

Long-wavelength VCSELs: Power-efficient answer

NASA Astrophysics Data System (ADS)

Kapon, Eli; Sirbu, Alexei

2009-01-01

The commercialization of long-wavelength vertical-cavity surface-emitting lasers (VCSELs) is gaining new momentum as the telecoms market shifts from long-haul applications to local and access networks. These small, power-efficient devices offer several advantages over traditional edge-emitters.

Trade studies for nuclear space power systems

NASA Technical Reports Server (NTRS)

Smith, John M.; Bents, David J.; Bloomfield, Harvey S.

1991-01-01

As human visions of space applications expand and as we probe further out into the universe, our needs for power will also expand, and missions will evolve which are enabled by nuclear power. A broad spectrum of missions which are enhanced or enabled by nuclear power sources have been defined. These include Earth orbital platforms, deep space platforms, planetary exploration, and terrestrial resource exploration. The recently proposed Space Exploration Initiative (SEI) to the Moon and Mars has more clearly defined these missions and their power requirements. Presented here are results of recent studies of radioisotope and nuclear reactor energy sources, combined with various energy conversion devices for Earth orbital applications, SEI lunar/Mars rovers, surface power, and planetary exploration.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

NASA Astrophysics Data System (ADS)

Balpande, Suresh S.; Pande, Rajesh S.

2016-04-01

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balpande, Suresh S., E-mail: balpandes@rknec.edu; Pande, Rajesh S.

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition tomore » this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and schottky diodes based voltage multiplier.« less

Advanced Thermal Simulator Testing: Thermal Analysis and Test Results

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David; Reid, Robert; Adams, Mike; Davis, Joe

2008-01-01

Work at the NASA Marshall Space Flight Center seeks to develop high fidelity, electrically heated thermal simulators that represent fuel elements in a nuclear reactor design to support non-nuclear testing applicable to the development of a space nuclear power or propulsion system. Comparison between the fuel pins and thermal simulators is made at the outer fuel clad surface, which corresponds to the outer sheath surface in the thermal simulator. The thermal simulators that are currently being tested correspond to a SNAP derivative reactor design that could be applied for Lunar surface power. These simulators are designed to meet the geometric and power requirements of a proposed surface power reactor design, accommodate testing of various axial power profiles, and incorporate imbedded instrumentation. This paper reports the results of thermal simulator analysis and testing in a bare element configuration, which does not incorporate active heat removal, and testing in a water-cooled calorimeter designed to mimic the heat removal that would be experienced in a reactor core.

Small reactor power systems for manned planetary surface bases

NASA Technical Reports Server (NTRS)

Bloomfield, Harvey S.

1987-01-01

A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

Fission Surface Power Technology Development Update

NASA Technical Reports Server (NTRS)

Palac, Donald T.; Mason, Lee S.; Houts, Michael G.; Harlow, Scott

2011-01-01

Power is a critical consideration in planning exploration of the surfaces of the Moon, Mars, and places beyond. Nuclear power is an important option, especially for locations in the solar system where sunlight is limited or environmental conditions are challenging (e.g., extreme cold, dust storms). NASA and the Department of Energy are maintaining the option for fission surface power for the Moon and Mars by developing and demonstrating technology for a fission surface power system. The Fission Surface Power Systems project has focused on subscale component and subsystem demonstrations to address the feasibility of a low-risk, low-cost approach to space nuclear power for surface missions. Laboratory demonstrations of the liquid metal pump, reactor control drum drive, power conversion, heat rejection, and power management and distribution technologies have validated that the fundamental characteristics and performance of these components and subsystems are consistent with a Fission Surface Power preliminary reference concept. In addition, subscale versions of a non-nuclear reactor simulator, using electric resistance heating in place of the reactor fuel, have been built and operated with liquid metal sodium-potassium and helium/xenon gas heat transfer loops, demonstrating the viability of establishing system-level performance and characteristics of fission surface power technologies without requiring a nuclear reactor. While some component and subsystem testing will continue through 2011 and beyond, the results to date provide sufficient confidence to proceed with system level technology readiness demonstration. To demonstrate the system level readiness of fission surface power in an operationally relevant environment (the primary goal of the Fission Surface Power Systems project), a full scale, 1/4 power Technology Demonstration Unit (TDU) is under development. The TDU will consist of a non-nuclear reactor simulator, a sodium-potassium heat transfer loop, a power conversion unit with electrical controls, and a heat rejection system with a multi-panel radiator assembly. Testing is planned at the Glenn Research Center Vacuum Facility 6 starting in 2012, with vacuum and liquid-nitrogen cold walls to provide simulation of operationally relevant environments. A nominal two-year test campaign is planned including a Phase 1 reactor simulator and power conversion test followed by a Phase 2 integrated system test with radiator panel heat rejection. The testing is expected to demonstrate the readiness and availability of fission surface power as a viable power system option for NASA's exploration needs. In addition to surface power, technology development work within this project is also directly applicable to in-space fission power and propulsion systems.

Status of Brayton Cycle Power Conversion Development at NASA GRC

NASA Technical Reports Server (NTRS)

Mason, Lee S.; Shaltens, Richard K.; Dolce, James L.; Cataldo, Robert L.

2002-01-01

The NASA Glenn Research Center (GRC) is pursuing the development of Brayton cycle power conversion for various NASA initiatives. Brayton cycle power systems offer numerous advantages for space power generation including high efficiency, long life, high maturity, and broad scalability. Candidate mission applications include surface rovers and bases, advanced propulsion vehicles, and earth orbiting satellites. A key advantage is the ability for Brayton converters to span the wide range of power demands of future missions from several kilowatts to multi-megawatts using either solar, isotope, or reactor heat sources. Brayton technology has been under development by NASA since the early 1960's resulting in engine prototypes in the 2 to 15 kW-class that have demonstrated conversion efficiency of almost 30% and cumulative operation in excess of 40,000 hours. Present efforts at GRC are focusing on a 2 kW testbed as a proving ground for future component advances and operational strategies, and a 25 kW engine design as a modular building block for 100 kW-class electric propulsion and Mars surface power applications.

Photovoltaic Power for Future NASA Missions

NASA Technical Reports Server (NTRS)

Landis, Geoffrey; Bailey, Sheila G.; Lyons, Valerie J. (Technical Monitor)

2002-01-01

Recent advances in crystalline solar cell technology are reviewed. Dual-junction and triple-junction solar cells are presently available from several U. S. vendors. Commercially available triple-junction cells consisting of GaInP, GaAs, and Ge layers can produce up to 27% conversion efficiency in production lots. Technology status and performance figures of merit for currently available photovoltaic arrays are discussed. Three specific NASA mission applications are discussed in detail: Mars surface applications, high temperature solar cell applications, and integrated microelectronic power supplies for nanosatellites.

Atmospheric pressure plasma jet's characterization and surface wettability driven by neon transformer

NASA Astrophysics Data System (ADS)

Elfa, R. R.; Nafarizal, N.; Ahmad, M. K.; Sahdan, M. Z.; Soon, C. F.

2017-03-01

Atmospheric pressure plasma driven by Neon transformer power supply argon is presented in this paper. Atmospheric pressure plasma system has attracted researcher interest over low pressure plasma as it provides a flexibility process, cost-efficient, portable device and vacuum-free device. Besides, another golden key of this system is the wide promising application in the field of work cover from industrial and engineering to medical. However, there are still numbers of fundamental investigation that are necessary such as device configuration, gas configuration and its effect. Dielectric barrier discharge which is also known as atmospheric pressure plasma discharge is created when there is gas ionization process occur which enhance the movement of atom and electron and provide energetic particles. These energetic particles can provide modification and cleaning property to the sample surface due to the bombardment of the high reactive ion and radicals to the sample surface. In order to develop atmospheric pressure plasma discharge, a high voltage and high frequency power supply is needed. In this work, we used a neon transformer power supply as the power supply. The flow of the Ar is feed into 10 mm cylinder quartz tube with different treatment time in order to investigate the effect of the plasma discharge. The analysis of each treatment time is presented by optical emission spectroscopy (OES) and water contact angle (WCA) measurement. The increase of gas treatment time shows increases intensity of reactive Ar and reduces the angle of water droplets in water contact angle. Treatment time of 20 s microslide glass surface shows that the plasma needle discharges have modified the sample surface from hydrophilic surface to superhydrophilic surface. Thus, this leads to another interesting application in reducing sample surface adhesion to optimize productivity in the industry of paintings, semiconductor and more.

Wedge cutting of mild steel by CO 2 laser and cut-quality assessment in relation to normal cutting

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Karatas, C.; Uslan, I.; Keles, O.; Usta, Y.; Yilbas, Z.; Ahsan, M.

2008-10-01

In some applications, laser cutting of wedge surfaces cannot be avoided in sheet metal processing and the quality of the end product defines the applicability of the laser-cutting process in such situations. In the present study, CO 2 laser cutting of the wedge surfaces as well as normal surfaces (normal to laser beam axis) is considered and the end product quality is assessed using the international standards for thermal cutting. The cut surfaces are examined by the optical microscopy and geometric features of the cut edges such as out of flatness and dross height are measured from the micrographs. A neural network is introduced to classify the striation patterns of the cut surfaces. It is found that the dross height and out of flatness are influenced significantly by the laser output power, particularly for wedge-cutting situation. Moreover, the cut quality improves at certain value of the laser power intensity.

A Comparison of Brayton and Stirling Space Nuclear Power Systems for Power Levels from 1 Kilowatt to 10 Megawatts

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2000-01-01

An analytical study was conducted to assess the performance and mass of Brayton and Stirling nuclear power systems for a wide range of future NASA space exploration missions. The power levels and design concepts were based on three different mission classes. Isotope systems, with power levels from 1 to 10 kW, were considered for planetary surface rovers and robotic science. Reactor power systems for planetary surface outposts and bases were evaluated from 10 to 500 kW. Finally, reactor power systems in the range from 100 kW to 10 mW were assessed for advanced propulsion applications. The analysis also examined the effect of advanced component technology on system performance. The advanced technologies included high temperature materials, lightweight radiators, and high voltage power management and distribution.

Future Opportunities for Dynamic Power Systems for NASA Missions

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.

2007-01-01

Dynamic power systems have the potential to be used in Radioisotope Power Systems (RPS) and Fission Surface Power Systems (FSPS) to provide high efficiency, reliable and long life power generation for future NASA applications and missions. Dynamic power systems have been developed by NASA over the decades, but none have ever operated in space. Advanced Stirling convertors are currently being developed at the NASA Glenn Research Center. These systems have demonstrated high efficiencies to enable high system specific power (>8 W(sub e)/kg) for 100 W(sub e) class Advanced Stirling Radioisotope Generators (ASRG). The ASRG could enable significant extended and expanded operation on the Mars surface and on long-life deep space missions. In addition, advanced high power Stirling convertors (>150 W(sub e)/kg), for use with surface fission power systems, could provide power ranging from 30 to 50 kWe, and would be enabling for both lunar and Mars exploration. This paper will discuss the status of various energy conversion options currently under development by NASA Glenn for the Radioisotope Power System Program for NASA s Science Mission Directorate (SMD) and the Prometheus Program for the Exploration Systems Mission Directorate (ESMD).

Surface Modification of Nonwoven fabrics by Atmospheric Brush Plasma

NASA Astrophysics Data System (ADS)

Oksuz, Lutfi; Uygun, Emre; Bozduman, Ferhat; Yurdabak Karaca, Gozde; Asan, Orkun Nuri; Uygun Oksuz, Aysegul

2017-10-01

Polypropylene nonwoven fabrics (PPNF) are used in disposable absorbent articles, such as diapers, feminine care products, wipes. PPNF need to be wettable by water or aqueous-based liquid. Plasma surface treatment/modification has turned out to be a well-accepted method since it offers superior surface property enhancement than other chemical methods. The cold plasma brush can most efficiently use the discharge power as well as the plasma gas for material and surface treatment. The very low power consumption of such an atmospheric argon plasma brush provides many unique advantages in practical application. The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of two different nonwoven surfaces.

Numerical modelling on stimulated Brillouin scattering characterization for Graphene-clad tapered silica fiber

NASA Astrophysics Data System (ADS)

Lee, Hui Jing; Abdullah, Fairuz; Ismail, Aiman

2017-11-01

This paper presents finite numerical modelling on the cross-sectional region of tapered single mode fiber and graphene-clad tapered fiber. Surface acoustic wave propagation across the tapered surface region on tapered single mode fiber has a high threshold power at 61.87 W which is challenging to overcome by the incident pump wave. Surface acoustic wave propagation of fiber surface however made tapered wave plausible in the optical sensor application. This research introduces graphene as the cladding layer on tapered fiber, acoustic confinement occurs due to the graphene cladding which lowers the threshold power from 61.87 W to 2.17 W.

Nuclear Power in Space.

ERIC Educational Resources Information Center

Department of Energy, Washington, DC. Nuclear Energy Office.

Research has shown that nuclear radioisotope power generators can supply compact, reliable, and efficient sources of energy for a broad range of space missions. These missions range from televising views of planetary surfaces to communicating scientific data to Earth. This publication presents many applications of the advancing technology and…

Atomic and molecular hydrogen gas temperatures in a low-pressure helicon plasma

NASA Astrophysics Data System (ADS)

Samuell, Cameron M.; Corr, Cormac S.

2015-08-01

Neutral gas temperatures in hydrogen plasmas are important for experimental and modelling efforts in fusion technology, plasma processing, and surface modification applications. To provide values relevant to these application areas, neutral gas temperatures were measured in a low pressure (< 10 mTorr) radiofrequency helicon discharge using spectroscopic techniques. The atomic and molecular species were not found to be in thermal equilibrium with the atomic temperature being mostly larger then the molecular temperature. In low power operation (< 1 kW), the molecular hydrogen temperature was observed to be linearly proportional to the pressure while the atomic hydrogen temperature was inversely proportional. Both temperatures were observed to rise linearly with input power. For high power operation (5-20 kW), the molecular temperature was found to rise with both power and pressure up to a maximum of approximately 1200 K. Spatially resolved measurements near a graphite target demonstrated localised cooling near the sample surface. The temporal evolution of the molecular gas temperature during a high power 1.1 ms plasma pulse was also investigated and found to vary considerably as a function of pressure.

Comparison of dynamic isotope power systems for distributed planet surface applications

NASA Technical Reports Server (NTRS)

Bents, David J.; Mckissock, Barbara I.; Hanlon, James C.; Schmitz, Paul C.; Rodriguez, Carlos D.; Withrow, Colleen A.

1991-01-01

Dynamic isotope power system (DIPS) alternatives were investigated and characterized for the surface mission elements associated with a lunar base and subsequent manned Mars expedition. System designs based on two convertor types were studied. These systems were characterized parametrically and compared over the steady-state electrical output power range 0.2 to 20 kWe. Three methods of thermally integrating the heat source and the Stirling heater head were considered, depending on unit size. Figures of merit were derived from the characterizations and compared over the parametric range. Design impacts of mission environmental factors are discussed and quantitatively assessed.

Recent Vertical External Cavity Surface Emitting Lasers (VECSELs) Developments for Sensor Applications (POSTPRINT)

DTIC Science & Technology

2013-02-01

edge-emitting strained InxGa1−xSb/AlyGa1−ySb quantum well struc- tures using solid-source molecular beam epitaxy (MBE) with varying barrier heights...intersubband quantum wells. The most common high-power edge-emitting semiconductor lasers suffter from poor beam quality, due primarily to the linewidth...reduces the power scalability of semiconductor lasers. In vertical cavity surface emitting lasers ( VCSELs ), light propagates parallel to the growth

Investigating the Use of Frequency Selective Surfaces in High Power Microwave Applications

DTIC Science & Technology

2010-03-01

radar applications were proving useful during World War II. Both allies and enemies were busy figuring out how to obtain, classify and use returns from...where the powers that are entering and leaving the network are represented by P in = 1 2 [a1a ∗ 1 + a2a ∗ 2] , (3.3) P out = 1 2 [b1b ∗ 1 + b2b ∗ 2

Proceedings of the Ship Control Systems Symposium (9th) Held in Bethesda, Maryland on 10-14 September 1990. Theme: Automation in Surface Ship Control Systems, Today’s Applications and Future Trends. Volume 4

DTIC Science & Technology

1990-09-14

and can be fused separately. The RTU’s low-power consumption makes them ideally suited for battery and solar powered applications. 3.5 Redundant...dei movimenti e delle sollecitazioni di una nave in mare tempestoso per mezzo del metodo dello spettro di energia e della teoria della

Mars Mission Surface Operation Simulation Testing of Lithium-Ion Batteries

NASA Technical Reports Server (NTRS)

Smart, M. C.; Bugga, R.; Whitcanack, L. D.; Chin, K. B.; Davies, E. D.; Surampudi, S.

2003-01-01

The objectives of this program are to 1) Assess viability of using lithium-ion technology for future NASA applications, with emphasis upon Mars landers and rovers which will operate on the planetary surface; 2) Support the JPL 2003 Mars Exploration Rover program to assist in the delivery and testing of a 8 AHr Lithium-Ion battery (Lithion/Yardney) which will power the rover; 3) Demonstrate applicability of using lithium-ion technologyfor future Mars applications: Mars 09 Science Laboratory (Smart Lander) and Future Mars Surface Operations (General). Mission simulation testing was carried out for cells and batteries on the Mars Surveyor 2001 Lander and the 2003 Mars Exploration Rover.

High power VCSELs for miniature optical sensors

NASA Astrophysics Data System (ADS)

Geske, Jon; Wang, Chad; MacDougal, Michael; Stahl, Ron; Follman, David; Garrett, Henry; Meyrath, Todd; Snyder, Don; Golden, Eric; Wagener, Jeff; Foley, Jason

2010-02-01

Recent advances in Vertical-cavity Surface-emitting Laser (VCSEL) efficiency and packaging have opened up alternative applications for VCSELs that leverage their inherent advantages over light emitting diodes and edge-emitting lasers (EELs), such as low-divergence symmetric emission, wavelength stability, and inherent 2-D array fabrication. Improvements in reproducible highly efficient VCSELs have allowed VCSELs to be considered for high power and high brightness applications. In this talk, Aerius will discuss recent advances with Aerius' VCSELs and application of these VCSELs to miniature optical sensors such as rangefinders and illuminators.

Feasibility of a 30-meter space based laser transmitter

NASA Technical Reports Server (NTRS)

Berggren, R. R.; Lenertz, G. E.

1975-01-01

A study was made of the application of large expandable mirror structures in future space missions to establish the feasibility and define the potential of high power laser systems for such applications as propulsion and power transmission. Application of these concepts requires a 30-meter diameter, diffraction limited mirror for transmission of the laser energy. Three concepts for the transmitter are presented. These concepts include consideration of continuous as well as segmented mirror surfaces and the major stow-deployment categories of inflatable, variable geometry and assembled-in-space structures. The mirror surface for each concept would be actively monitored and controlled to maintain diffraction limited performance at 10.6 microns during operation. The proposed mirror configurations are based on existing aerospace state-of-the-art technology. The assembled-in-space concept appears to be the most feasible, at this time.

High-power, format-flexible, 885-nm vertical-cavity surface-emitting laser arrays

NASA Astrophysics Data System (ADS)

Wang, Chad; Talantov, Fedor; Garrett, Henry; Berdin, Glen; Cardellino, Terri; Millenheft, David; Geske, Jonathan

2013-03-01

High-power, format flexible, 885 nm vertical-cavity surface-emitting laser (VCSEL) arrays have been developed for solid-state pumping and illumination applications. In this approach, a common VCSEL size format was designed to enable tiling into flexible formats and operating configurations. The fabrication of a common chip size on ceramic submount enables low-cost volume manufacturing of high-power VCSEL arrays. This base VCSEL chip was designed to be 5x3.33 mm2, and produced up to 50 Watts of peak continuous wave (CW) power. To scale to higher powers, multiple chips can be tiled into a combination of series or parallel configurations tailored to the application driver conditions. In actively cooled CW operation, the VCSEL array chips were packaged onto a single water channel cooler, and we have demonstrated 0.5x1, 1x1, and 1x3 cm2 formats, producing 150, 250, and 500 Watts of peak power, respectively, in under 130 A operating current. In QCW operation, the 1x3 cm2 VCSEL module, which contains 18 VCSEL array chips packaged on a single water cooler, produced over 1.3 kW of peak power. In passively cooled packages, multiple chip configurations have been developed for illumination applications, producing over 300 Watts of peak power in QCW operating conditions. These VCSEL chips use a substrate-removed structure to allow for efficient thermal heatsinking to enable high-power operation. This scalable, format flexible VCSEL architecture can be applied to wavelengths ranging from 800 to 1100 nm, and can be used to tailor emission spectral widths and build high-power hyperspectral sources.

Soluble calcium amendments: reducing pathogen losses

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization (FGD) gypsum is a byproduct of coal-fired power plants. Its application to agricultural fields may increase water infiltration, reduce soil erosion, and decrease nutrient losses from applications of animal manures. It may also reduce fecal bacterial contamination of surface ...

Effective of diode laser on teeth enamel in the teeth whitening treatment

NASA Astrophysics Data System (ADS)

Klunboot, U.; Arayathanitkul, K.; Chitaree, R.; Emarat, N.

2011-12-01

This research purpose is to investigate the changing of teeth color and to study the surface of teeth after treatment by laser diode at different power densities for tooth whitening treatment. In the experiment, human-extracted teeth samples were divided into 7 groups of 6 teeth each. After that laser diode was irradiated to teeth, which were coated by 38% concentration of hydrogen peroxide, during for 20, 30 and 60 seconds at power densities of 10.9 and 52.1 W/cm2. The results of teeth color change were described by the CIEL*a*b* systems and the damage of teeth surface were investigated by scanning electron microscopy (SEM). The results showed that the power density of the laser diode could affect the whiteness of teeth. The high power density caused more luminous teeth than the low power density did, but on the other hand the high power density also caused damage to the teeth surface. Therefore, the laser diode at the low power densities has high efficiency for tooth whitening treatment and it has a potential for other clinical applications.

Surface modification: advantages, techniques, and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Natesan, K.

2000-03-01

Adequate performance of materials at elevated temperatures is a potential problem in many systems within the chemical, petroleum, process, and power-generating industries. Degradation of materials occurs because of interaction between the structural material and the exposure environment. These interactions are generally undesired chemical reactions that can lead to accelerated wastage and alter the functional requirements and/or structural integrity of the materials. Therefore, material selection for high-temperature applications must be based not only on a material strength properties but also on resistance to the complex environments prevalent in the anticipated exposure environment. As plants become larger, the satisfactory performance and reliabilitymore » of components play a greater role in plant availability and economics. However, system designers are becoming increasingly concerned with finding the least expensive material that will satisfactorily perform the design function for the desired service life. This present paper addresses the benefits of surface modification and identified several criteria for selection and application of modified surfaces in the power sector. A brief review is presented on potential methods for modification of surfaces, with the emphasis on coatings. In the final section of the paper, several examples address the requirements of different energy systems and surface modification avenues that have been applied to resolve the issues.« less

Development of lithium and tungsten limiters for test on T-10 tokamak at high heat load condition

NASA Astrophysics Data System (ADS)

Lyublinski, I. E.; Vertkov, A. V.; Zharkov, M. Yu; Vershkov, V. A.; Mirnov, S. V.

2016-04-01

Application of a complex of powerful (up to 3 MW) ECR plasma heating in T-10 tokamak is pulled down with a problem of the strong plasma pollution at power input more than 2 MW. For the solution of these problems the new W and Li limiters is developed and prepared to implementation. As it is supposed, application of W as a plasma facing material will allow excluding carbon influx into vacuum chamber. An additional Li limiter arranged in a shadow of W one will be used as a Li source for plasma periphery cooling due to a reradiation on Li that will lead to decrease in power deposition on W limiters. Parameters and design of limiters are presented. Plasma facing surface of a limiter is made of capillary-porous system (CPS) with Li. Porous matrix of CPS (W felt) provides stability of liquid Li surface under MHD force effect and an opportunity of its constant renewal due to capillary forces. The necessary Li flux from a Li limiter surface is estimated for maintenance of normal operation mode of W limiters at ECRH power of 3 MW during 400 ms. It is shown, that upgrade of limiters in tokamak T-10 will allow providing of ECR plasma heating with power up to 3 MW at reasonable Li flux.

[The heating effect of the Er3+/Yb3+ doped Y2O3 nanometer powder by 980 nm laser diode pumping].

PubMed

Zheng, Long-Jiang; Gao, Xiao-Yang; Liu, Hai-Long; Li, Bing; Xu, Chen-Xi

2013-01-01

The Er3+ and Yb3+ doped Y2O3 Nano powder was prepared by sol-gel method. Based on 2H11/2 --> 4I15/2 and 4S3/2 --> 4I15/2 green conversion luminescence intensity rate of Er3+, the sample surface temperature changes caused by the increase in 980 nm diode laser pump power were studied. The results show that with pump power increasing, the sample surface temperature substantially rises. And the surface temperature reached to 820 K when the pump power was 1 000 mW. The phenomenon plays an important role in the analysis of upconversion process, especially with saturation power. And this feature has a potential application prospect in the biomedicine, soft tissue hole burning as well as the field of temperature sensing materials.

Microwave surface resistance of MgB2

NASA Astrophysics Data System (ADS)

Zhukov, A. A.; Purnell, A.; Miyoshi, Y.; Bugoslavsky, Y.; Lockman, Z.; Berenov, A.; Zhai, H. Y.; Christen, H. M.; Paranthaman, M. P.; Lowndes, D. H.; Jo, M. H.; Blamire, M. G.; Hao, Ling; Gallop, J.; MacManus-Driscoll, J. L.; Cohen, L. F.

2002-04-01

The microwave power and frequency dependence of the surface resistance of MgB2 films and powder samples were studied. Sample quality is relatively easy to identify by the breakdown in the ω2 law for poor-quality samples at all temperatures. The performance of MgB2 at 10 GHz and 21 K was compared directly with that of high-quality YBCO films. The surface resistance of MgB2 was found to be approximately three times higher at low microwave power and showed an onset of nonlinearity at microwave surface fields ten times lower than the YBCO film. It is clear that MgB2 films are not yet optimized for microwave applications.

A temperature control design for a tapered element oscillating microbalance sensing surface

NASA Technical Reports Server (NTRS)

1982-01-01

A design study is presented which shows that a tapered element oscillating microbalance can be adapted for temperature control under space application by mating with multistage thermoelectric coolers in such a way that an integral structure evolves. The control of the temperature of the sensing surface can be achieved in a number of ways. An indirect method which uses a measurement of the absorbed power is recommended. The design goals can be met if a relaxation of the power requirement can be considered.

Imprinting continuously varying topographical structure onto large-aperture optical surfaces using magnetorheological finishing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menapace, J A; Davis, P J; Dixit, S

2007-03-07

Over the past four years we have advanced Magnetorheological Finishing (MRF) techniques and tools to imprint complex continuously varying topographical structures onto large-aperture (430 x 430 mm) optical surfaces. These optics, known as continuous phase plates (CPPs), are important for high-power laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm and surface peak-to-valleys as high as 22 {micro}m. During this discussion, we will present the evolution of the MRF imprinting technology and themore » MRF tools designed to manufacture large-aperture 430 x 430 mm CPPs. Our results will show how the MRF removal function impacts and limits imprint fidelity and what must be done to arrive at a high-quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use in high-power laser applications.« less

30 CFR 36.6 - Application procedures and requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... diesel engine, including joints and gaskets; the turbulence or precombustion chamber, if applicable; injector assembly and nozzle details; and any surfaces that form the combustion chamber or part thereof..., EVALUATION, AND APPROVAL OF MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED...

Coherent beam combiner for a high power laser

DOEpatents

Dane, C. Brent; Hackel, Lloyd A.

2002-01-01

A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

Trends in high power laser applications in civil engineering

NASA Astrophysics Data System (ADS)

Wignarajah, Sivakumaran; Sugimoto, Kenji; Nagai, Kaori

2005-03-01

This paper reviews the research and development efforts made on the use of lasers for material processing in the civil engineering industry. Initial investigations regarding the possibility of using lasers in civil engineering were made in the 1960s and '70s, the target being rock excavation. At that time however, the laser powers available were too small for any practical application utilization. In the 1980's, the technology of laser surface cleaning of historically important structures was developed in Europe. In the early 1990s, techniques of laser surface modification, including glazing and coloring of concrete, roughening of granite stones, carbonization of wood were pursued, mainly in Japan. In the latter part of the decade, techniques of laser decontamination of concrete surfaces in nuclear facilities were developed in many countries, and field tests were caried out in Japan. The rapid advances in development of diode lasers and YAG lasers with high power outputs and efficiencies since the late 1990's have led to a revival of worldwide interest in the use of lasers for material processing in civil engineering. The authors believe that, in the next 10 years or so, the advent of compact high power lasers is likely to lead to increased use of lasers of material processing in the field of civil engineering.

Surface properties of magnetite in high temperature aqueous electrolyte solutions: A review.

PubMed

Vidojkovic, Sonja M; Rakin, Marko P

2017-07-01

Deposits and scales formed on heat transfer surfaces in power plant water/steam circuits have a significant negative impact on plant reliability, availability and performance, causing tremendous economic consequences and subsequent increases in electricity cost. Consequently, the improvement of the understanding of deposition mechanisms on power generating surfaces is defined as a high priority in the power industry. The deposits consist principally of iron oxides, which are steel corrosion products and usually present in colloidal form. Magnetite (Fe 3 O 4 ) is the predominant and most abundant compound found in water/steam cycles of all types of power plants. The crucial factor that governs the deposition process and influences the deposition rate of magnetite is the electrostatic interaction between the metal wall surfaces and the suspended colloidal particles. However, there is scarcity of data on magnetite surface properties at elevated temperatures due to difficulties in their experimental measurement. In this paper a generalized overview of existing experimental data on surface characteristics of magnetite at high temperatures is presented with particular emphasis on possible application in the power industry. A thorough analysis of experimental techniques, mathematical models and results has been performed and directions for future investigations have been considered. The state-of-the-art assessment showed that for the characterization of magnetite/aqueous electrolyte solution interface at high temperatures acid-base potentiometric titrations and electrophoresis were the most beneficial and dependable techniques which yielded results up to 290 and 200°C, respectively. Mass titrations provided data on magnetite surface charge up to 320°C, however, this technique is highly sensitive to the minor concentrations of impurities present on the surface of particle. Generally, fairly good correlation between the isoelectric point (pH iep ) and point of zero charge (pH pzc ) values has been obtained. All obtained results showed that the surface of magnetite particles is negatively charged in typical high temperature thermal power plant water, which indicates the low probability of aggregation and deposition on plant metal surfaces. The results also gave strong evidence on decline of pH iep and pH pzc with temperature in the same manner as neutral pH of water. The thermodynamic parameters of magnetite surface protonation reactions were in good agreement with each other and obtained using one site/two pK and mainly one site/one pK model. All collected data provided evidences for interaction between particles, probability of deposition and eventual attachment to the steel surface at various pH and temperatures and can serve as a foundation for future surface studies aimed at optimizing plant performances and reducing of magnetite deposition. In future works it would be indispensable to provide the surface experimental data for extended temperature ranges, typical solution chemistries and metal surfaces of power plant structural components and thus obtain entire set of results useful in modeling the surface behavior and control of deposition process in power reactors and thermal plant circuits. Moreover, the acquired results will be applicable and greatly valuable to all other types of power plants, industrial facilities and technological processes using the high temperature water medium. Copyright © 2016 Elsevier B.V. All rights reserved.

Vertical-cavity surface-emitting lasers: the applications

NASA Astrophysics Data System (ADS)

Morgan, Robert A.; Lehman, John A.; Hibbs-Brenner, Mary K.; Liu, Yue; Bristow, Julian P. G.

1997-05-01

In this paper, we focus on how vertical-cavity surface- emitting lasers (VCSELs) and arrays have led to many feasible advanced technological applications. Their intrinsic characteristics, performance, and producibility offer substantial advantages over alternative sources. Demonstrated performance of `commercial-grade' VCSELs include low operating powers (< 2 V, mAs), high speeds (3 dB BWs > 15 GHz), and high temperature operating ranges (10 K to 400 K and -55 degree(s)C to 125 degree(s)C, and T > 200 degree(s)C). Moreover, their robustness is manifest by high reliability in excess of 107 hours mean time between failures at room temperature and tenfold improvement over existing rad-hard LEDs. Hence, even these `commercial-grade' VCSELs offer potential within cryogenic and avionics/military or space environments. We have also demonstrated submilliamp ITH, stable, single-mode VCSELs utilized within bias-free 1-Gbit/s data links. These low- power VCSELs may also serve in applications from printers to low-cost atomic clocks. The greatest near-term VCSEL applications are upgrades to low-cost LEDs and high-grade copper wire in data links and sensors. Exploiting their surface-emitting geometry, VCSELs are also compatible with established multichip module packaging. Hence VCSELs and VCSEL arrays are ideal components for interconnect-intensive processing applications between and within computing systems.

Surface acoustic wave unidirectional transducers for quantum applications

NASA Astrophysics Data System (ADS)

Ekström, Maria K.; Aref, Thomas; Runeson, Johan; Björck, Johan; Boström, Isac; Delsing, Per

2017-02-01

The conversion efficiency of electric microwave signals into surface acoustic waves in different types of superconducting transducers is studied with the aim of quantum applications. We compare delay lines containing either conventional symmetric transducers (IDTs) or unidirectional transducers (UDTs) at 2.3 GHz and 10 mK. The UDT delay lines improve the insertion loss with 4.7 dB and a directivity of 22 dB is found for each UDT, indicating that 99.4% of the acoustic power goes in the desired direction. The power lost in the undesired direction accounts for more than 90% of the total loss in IDT delay lines, but only ˜3% of the total loss in the floating electrode unidirectional transducer delay lines.

System Concepts for Affordable Fission Surface Power

NASA Technical Reports Server (NTRS)

Mason, Lee; Poston, David; Qualls, Louis

2008-01-01

This paper presents an overview of an affordable Fission Surface Power (FSP) system that could be used for NASA applications on the Moon and Mars. The proposed FSP system uses a low temperature, uranium dioxide-fueled, liquid metal-cooled fission reactor coupled to free-piston Stirling converters. The concept was determined by a 12 month NASA/DOE study that examined design options and development strategies based on affordability and risk. The system is considered a low development risk based on the use of terrestrial-derived reactor technology, high efficiency power conversion, and conventional materials. The low-risk approach was selected over other options that could offer higher performance and/or lower mass.

Feasibility study of surface-modified carbon cloth electrodes using atmospheric pressure plasma jets for microbial fuel cells

NASA Astrophysics Data System (ADS)

Chang, Shih-Hang; Liou, Jyun-Sian; Liu, Jung-Liang; Chiu, Yi-Fan; Xu, Chang-Han; Chen, Bor-Yann; Chen, Jian-Zhang

2016-12-01

This study investigated the surface and electrochemical properties of carbon cloth electrodes surface-modified by using atmospheric pressure plasma jets (APPJs) for applications involving microbial fuel cells (MFCs). APPJ treatment made the carbon cloth highly hydrophilic and did not introduce any observable cracks or flaws. MFCs configured with APPJ-treated carbon cloth electrodes exhibited electrochemical performance (maximum power density of 7.56 mW m-2) superior to that of MFCs configured with untreated carbon cloth electrodes (maximum power density of 2.38 mW m-2). This boost in performance can be attributed to the formation of abundant carboxyl and ammonium functional groups on the surface of APPJ-treated carbon cloth, which promoted the formation of anodic biofilms and the adhesion of bacteria, while facilitating the transfer of electrons from the bacteria to the electrodes. APPJ surface modification is non-toxic and environmentally friendly (no exogenous chemicals are required), which is particularly beneficial as the introduction of toxins might otherwise inhibit bacterial growth and metabolism. The APPJ surface modification process is rapid, cost-effective, and applicable to substrates covering a large area, making it ideal for the fabrication of large-scale MFCs and bioelectrochemical bioenergy devices.

Performance of Surface-Mount Ceramic and Solid Tantalum Capacitors for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; MacDonald, Thomas L.; Hammoud, Ahmad; Gerber, Scott

1998-01-01

Low temperature electronics are of great interest for space exploration programs. These include missions to the outer planets, earth-orbiting and deep-space probes, remote-sensing and communication satellites. Terrestrial applications would also benefit from the availability of low temperature electronics. Power components capable of low temperature operation would, thus, enhance the technologies needed for the development of advanced power systems suitable for use in harsh environments. In this work, ceramic and solid tantalum capacitors were evaluated in terms of their dielectric properties as a function of temperature and at various frequencies. The surface-mount devices were characterized in terms of their capacitance stability and dissipation factor in the frequency range of 50 Hz to 100 kHz at temperatures ranging from room temperature (20 deg. C) to about liquid nitrogen temperature (-190 deg. C). The results are discussed and conclusions made concerning the suitability of the capacitors investigated for low temperature applications.

The effect of leveling coatings on the atomic oxygen durability of solar concentrator surfaces

NASA Technical Reports Server (NTRS)

Degroh, Kim K.; Dever, Therese M.; Quinn, William F.

1990-01-01

Space power systems for Space Station Freedom will be exposed to the harsh environment of low earth orbit (LEO). Neutral atomic oxygen is the major constituent in LEO and has the potential of severely reducing the efficiency of solar dynamic power systems through degradation of the concentrator surfaces. Several transparent dielectric thin films have been found to provide atomic oxygen protection, but atomic oxygen undercutting at inherent defect sites is still a threat to solar dynamic power system survivability. Leveling coatings smooth microscopically rough surfaces, thus eliminating potential defect sites prone to oxidation attack on concentrator surfaces. The ability of leveling coatings to improve the atomic oxygen durability of concentrator surfaces was investigated. The application of a EPO-TEK 377 epoxy leveling coating on a graphite epoxy substrate resulted in an increase in solar specular reflectance, a decrease in the atomic oxygen defect density by an order of magnitude and a corresponding order of magnitude decrease in the percent loss of specular reflectance during atomic oxygen plasma ashing.

High-efficiency VCSEL arrays for illumination and sensing in consumer applications

NASA Astrophysics Data System (ADS)

Seurin, Jean-Francois; Zhou, Delai; Xu, Guoyang; Miglo, Alexander; Li, Daizong; Chen, Tong; Guo, Baiming; Ghosh, Chuni

2016-03-01

There has been increased interest in vertical-cavity surface-emitting lasers (VCSELs) for illumination and sensing in the consumer market, especially for 3D sensing ("gesture recognition") and 3D image capture. For these applications, the typical wavelength range of interest is 830~950nm and power levels vary from a few milli-Watts to several Watts. The devices are operated in short pulse mode (a few nano-seconds) with fast rise and fall times for time-of-flight applications (ToF), or in CW/quasi-CW for structured light applications. In VCSELs, the narrow spectrum and its low temperature dependence allows the use of narrower filters and therefore better signal-to-noise performance, especially for outdoor applications. In portable devices (mobile devices, wearable devices, laptops etc.) the size of the illumination module (VCSEL and optics) is a primary consideration. VCSELs offer a unique benefit compared to other laser sources in that they are "surface-mountable" and can be easily integrated along with other electronics components on a printed circuit board (PCB). A critical concern is the power-conversion efficiency (PCE) of the illumination source operating at high temperatures (>50 deg C). We report on various VCSEL based devices and diffuser-integrated modules with high efficiency at high temperatures. Over 40% PCE was achieved in broad temperature range of 0-70 °C for either low power single devices or high power VCSEL arrays, with sub- nano-second rise and fall time. These high power VCSEL arrays show excellent reliability, with extracted mean-time-to-failure (MTTF) of over 500 years at 60 °C ambient temperature and 8W peak output.

An Investigation of the Effectiveness of Solar Power on Navy Surface Combatants

DTIC Science & Technology

2013-09-01

addition , this could cause a measureable reduction in the Navy’s environmental impact, especially since solar power can be generated both when the ships...that a relatively small addition in overall ship’s displacement would be required to implement a solar power system. Additionally, the solar cells...as a source of pulse power for large electrical loads such as high - energy weapons or radars. Both these applications are well within the current

Interfacial Dirac cones from alternating topological invariant superlattice structures of Bi2Se3.

PubMed

Song, Jung-Hwan; Jin, Hosub; Freeman, Arthur J

2010-08-27

When the three-dimensional topological insulators Bi2Se3 and Bi2Te3 have an interface with vacuum, i.e., a surface, they show remarkable features such as topologically protected and spin-momentum locked surface states. However, for practical applications, one often requires multiple interfaces or channels rather than a single surface. Here, for the first time, we show that an interfacial and ideal Dirac cone is realized by alternating band and topological insulators. The multichannel Dirac fermions from the superlattice structures open a new way for applications such as thermoelectric and spintronics devices. Indeed, utilizing the interfacial Dirac fermions, we also demonstrate the possible power factor improvement for thermoelectric applications.

Advanced photovoltaic power system technology for lunar base applications

NASA Astrophysics Data System (ADS)

Brinker, David J.; Flood, Dennis J.

1992-09-01

The development of an advanced photovoltaic power system that would have application for a manned lunar base is currently planned under the Surface Power element of Pathfinder. Significant mass savings over state-of-the-art photovoltaic/battery systems are possible with the use of advanced lightweight solar arrays coupled with regenerative fuel cell storage. The solar blanket, using either ultrathin GaAs or amorphous silicon solar cells, would be integrated with a reduced-g structure. Regenerative fuel cells with high-pressure gas storage in filament-wound tanks are planned for energy storage. An advanced PV/RFC power system is a leading candidate for a manned lunar base as it offers a tremendous weight advantage over state-of-the-art photovoltaic/battery systems and is comparable in mass to other advanced power generation technologies.

Application of Molten Salt Reactor Technology to Nuclear Electric Propulsion Mission

NASA Technical Reports Server (NTRS)

Patton, Bruce; Sorensen, Kirk; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

Nuclear electric propulsion (NEP) and planetary surface power missions require reactors that are lightweight, operationally robust, and scalable in power for widely varying scientific mission objectives. Molten salt reactor technology meets all of these requirements and offers an interesting alternative to traditional gas cooled, liquid metal, and heat pipe space reactors.

Electrical characterization of a Mapham inverter using pulse testing techniques

NASA Technical Reports Server (NTRS)

Baumann, E. D.; Myers, I. T.; Hammond, A. N.

1990-01-01

Electric power requirements for aerospace missions have reached megawatt power levels. Within the next few decades, it is anticipated that a manned lunar base, interplanetary travel, and surface exploration of the Martian surface will become reality. Several research and development projects aimed at demonstrating megawatt power level converters for space applications are currently underway at the NASA Lewis Research Center. Innovative testing techniques will be required to evaluate the components and converters, when developed, at their rated power in the absence of costly power sources, loads, and cooling systems. Facilities capable of testing these components and systems at full power are available, but their use may be cost prohibitive. The use of a multiple pulse testing technique is proposed to determine the electrical characteristics of large megawatt level power systems. Characterization of a Mapham inverter is made using the proposed technique and conclusions are drawn concerning its suitability as an experimental tool to evaluate megawatt level power systems.

Stirling Isotope Power Systems for Stationary and Mobile Lunar Applications

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

2007-01-01

The NASA Exploration Systems Architecture Study (ESAS) places a significant emphasis on the development of a wide range of capabilities on the lunar surface as a stepping-stone to further space exploration. An important aspect of developing these capabilities will be the availability of reliable, efficient, and low-mass power systems to support both stationary and mobile applications. One candidate system to provide electrical power is made by coupling the General Purpose Heat Source (GPHS) with a high-performance Stirling convertor. In this paper we explore the practical power range of GPHS/Stirling convertor systems all with conductively coupled hot-end designs for use on the lunar surface. Design and off-design operations during the life of the convertor are studied in addition to considering these varying conditions on system. Unique issues concerning Stirling convertor configurations, integration of the GPHS with the Stirling convertor, controller operation, waste heat rejection, and thermal protection are explored. Of particular importance in the evaluation process is a thorough understanding of the interactions between the wide range of unique lunar environments and the selection of key systems operating characteristics and the power systems design. Additionally, as power levels rise the interface between the GPHS and Stirling and the Stirling and the radiator begins to dominate system mass and material selection becomes more important.

The study of non-fouling and non-specific cellular binding on functionalized surface for mammalian cell identification and manipulation

NASA Astrophysics Data System (ADS)

Zainudin, Nor Syuhada; Hambali, Nor Azura Malini Ahmad; Wahid, Mohamad Halim Abd; Retnasamy, Vithyacharan; Shahimin, Mukhzeer Mohamad

2017-04-01

Surface functionalization has emerged as a powerful tool for mapping limitless surface-cell membrane interaction in diverse biomolecular applications. Inhibition of non-specific biomolecular and cellular adhesion to solid surfaces is critical in improving the performance of some biomedical devices, particularly for in vitro bioassays. Some factors have to be paid particular attention in determining the right surface modification which are the types of surface, the methods and chemical solution that being used during the experimentation and also tools for analyzing the results. Improved surface functionalization technologies that provide better non-fouling performance in conjunction with specific attachment chemistries are sought for these applications. Hence, this paper serves as a review for multiple surface treatment methods including PEG grafting, adsorptive chemistries, self-assembled monolayers (SAMs) and plasma treatments.

Active plasmonics in WDM traffic switching applications

NASA Astrophysics Data System (ADS)

Papaioannou, Sotirios; Kalavrouziotis, Dimitrios; Vyrsokinos, Konstantinos; Weeber, Jean-Claude; Hassan, Karim; Markey, Laurent; Dereux, Alain; Kumar, Ashwani; Bozhevolnyi, Sergey I.; Baus, Matthias; Tekin, Tolga; Apostolopoulos, Dimitrios; Avramopoulos, Hercules; Pleros, Nikos

2012-09-01

With metal stripes being intrinsic components of plasmonic waveguides, plasmonics provides a ``naturally'' energy-efficient platform for merging broadband optical links with intelligent electronic processing, instigating a great promise for low-power and small-footprint active functional circuitry. The first active Dielectric-Loaded Surface Plasmon Polariton (DLSPP) thermo-optic (TO) switches with successful performance in single-channel 10 Gb/s data traffic environments have led the inroad towards bringing low-power active plasmonics in practical traffic applications. In this article, we introduce active plasmonics into Wavelength Division Multiplexed (WDM) switching applications, using the smallest TO DLSPP-based Mach-Zehnder interferometric switch reported so far and showing its successful performance in 4×10 Gb/s low-power and fast switching operation. The demonstration of the WDM-enabling characteristics of active plasmonic circuits with an ultra-low power × response time product represents a crucial milestone in the development of active plasmonics towards real telecom and datacom applications, where low-energy and fast TO operation with small-size circuitry is targeted.

Development of a robust space power system decision model

NASA Astrophysics Data System (ADS)

Chew, Gilbert; Pelaccio, Dennis G.; Jacobs, Mark; Stancati, Michael; Cataldo, Robert

2001-02-01

NASA continues to evaluate power systems to support human exploration of the Moon and Mars. The system(s) would address all power needs of surface bases and on-board power for space transfer vehicles. Prior studies have examined both solar and nuclear-based alternatives with respect to individual issues such as sizing or cost. What has not been addressed is a comprehensive look at the risks and benefits of the options that could serve as the analytical framework to support a system choice that best serves the needs of the exploration program. This paper describes the SAIC developed Space Power System Decision Model, which uses a formal Two-step Analytical Hierarchy Process (TAHP) methodology that is used in the decision-making process to clearly distinguish candidate power systems in terms of benefits, safety, and risk. TAHP is a decision making process based on the Analytical Hierarchy Process, which employs a hierarchic approach of structuring decision factors by weights, and relatively ranks system design options on a consistent basis. This decision process also includes a level of data gathering and organization that produces a consistent, well-documented assessment, from which the capability of each power system option to meet top-level goals can be prioritized. The model defined on this effort focuses on the comparative assessment candidate power system options for Mars surface application(s). This paper describes the principles of this approach, the assessment criteria and weighting procedures, and the tools to capture and assess the expert knowledge associated with space power system evaluation. .

Applications of high power lasers. [using reflection holograms for machining and surface treatment

NASA Technical Reports Server (NTRS)

Angus, J. C.

1979-01-01

The use of computer generated, reflection holograms in conjunction with high power lasers for precision machining of metals and ceramics was investigated. The Reflection holograms which were developed and made to work at both optical wavelength (He-Ne, 6328 A) and infrared (CO2, 10.6) meet the primary practical requirement of ruggedness and are relatively economical and simple to fabricate. The technology is sufficiently advanced now so that reflection holography could indeed be used as a practical manufacturing device in certain applications requiring low power densities. However, the present holograms are energy inefficient and much of the laser power is lost in the zero order spot and higher diffraction orders. Improvements of laser machining over conventional methods are discussed and addition applications are listed. Possible uses in the electronics industry include drilling holes in printed circuit boards making soldered connections, and resistor trimming.

Mars power system concept definition study. Volume 1: Study results

NASA Technical Reports Server (NTRS)

Littman, Franklin D.

1994-01-01

A preliminary top level study was completed to define power system concepts applicable to Mars surface applications. This effort included definition of power system requirements and selection of power systems with the potential for high commonality. These power systems included dynamic isotope, Proton Exchange Membrane (PEM) regenerative fuel cell, sodium sulfur battery, photovoltaic, and reactor concepts. Design influencing factors were identified. Characterization studies were then done for each concept to determine system performance, size/volume, and mass. Operations studies were done to determine emplacement/deployment maintenance/servicing, and startup/shutdown requirements. Technology development roadmaps were written for each candidate power system (included in Volume 2). Example power system architectures were defined and compared on a mass basis. The dynamic isotope power system and nuclear reactor power system architectures had significantly lower total masses than the photovoltaic system architectures. Integrated development and deployment time phasing plans were completed for an example DIPS and reactor architecture option to determine the development strategies required to meet the mission scenario requirements.

Feasibility of solar power for Mars

NASA Technical Reports Server (NTRS)

Appelbaum, Joseph; Landis, Geoffrey A.

1991-01-01

NASA, through Project Pathfinder, has put in place an advanced technology program to address future needs of manned space exploration. Included in the missions under study is the establishment of outposts on the surface of Mars. The Surface Power program in Pathfinder is aimed at providing photovoltaic array technology for such an application (as well as for the lunar surface). Another important application is for unmanned precursor missions, such as the photovoltaic-power aircraft, which will scout landing sites and investigate Mars geology for a 1 to 2 year mission without landing on the surface. Effective design and utilization of solar energy depend to a large extent on adequate knowledge of solar radiation characteristics in the region of solar energy system operation. The two major climatic components needed for photovoltaic system designs are the distributions of solar insolation and ambient temperature. These distributions for the Martian climate are given at the two Viking lander locations but can also be used, to the first approximation, for other latitudes. One of the most important results is that there is a large diffuse component of the insolation, even at high optical depth, so that solar energy system operation is still possible. If the power system is to continue to generate power even on high optical opacity days, it is thus important that the photovoltaic system be designed to collect diffuse irradiance as well as direct. In absence of long term insolation and temperature data for Mars, the data presented can be used until updated data are available. The ambient temperature data are given as measured directly by the temperature sensor; the insolation data are calculated from optical depth measurements of the atmosphere.

Multiphase High-Frequency Isolated DC-DC Converter for Industrial Applications

NASA Astrophysics Data System (ADS)

Maurya, Rakesh; Srivastava, S. P.; Agarwal, Pramod

2014-01-01

Industrial applications such as welding, plasma cutting, and surface hardening require a large DC current at low voltage. In such applications, the rating of power supply varies from few kilowatts to hundreds of kilowatts. The power supply employs in such applications particularly in arc welding process is expected to operate from open-circuit (no-load) to short-circuit (when the electrode sticks to the workpiece for a short span of time) quickly. In this paper, high-frequency isolated multiphase DC-DC converter is proposed which is well suited for aforementioned applications. Based on mathematical analysis, a simulation study with 5 kW, 5 V/1,000 A proposed model is carried out using Simulink block set and Sim Power System tool box and its performances are evaluated under symmetrical control methods. To verify the simulation results, scaled prototype model of rating 1.5 V/100 A is developed and tested with aforementioned control method under different operating conditions. In comparison with conventional welding power supply employed in many industries, the performance of proposed converter is improved significantly in terms of size and weight, efficiency and dynamic response.

Miniature microwave powered steam sterilization chamber

NASA Astrophysics Data System (ADS)

Atwater, James E.; Dahl, Roger W.; Garmon, Frank C.; Lunsford, Teddie D.; Michalek, William F.; Wheeler, Richard R., Jr.; Sauer, Richard L.

1997-10-01

A small device for the rapid ultrahigh temperature sterilization of surfaces is described. Microwave power generated by a 2.45 GHz magnetron is delivered via coaxial cable to a silicon carbide block housed within the chamber. Small quantities of water or aqueous hydrogen peroxide are introduced into the chamber. Upon application of power, the liquid flashes to vapor and superheats producing temperatures to 300 °C. The hot vapor permeates the enclosed space and contacts all exposed surfaces. Complete microbial kill of >10 6 colony forming units of the spore forming thermophile, Bacillus stearothermophilus, has been demonstrated using a variety of temperatures and exposure times in both steady state and thermal pulse modes of operation.

Methods and apparatus for delivering high power laser energy to a surface

DOEpatents

Faircloth, Brian O; Zediker, Mark S; Rinzler, Charles C; Koblick, Yeshaya; Moxley, Joel F

2013-04-23

There is provided a system, apparatus and methods for providing a laser beam to borehole surface in a predetermined and energy deposition profile. The predetermined energy deposition profiles may be uniform or tailored to specific downhole applications. Optic assemblies for obtaining these predetermined energy deposition profiles are further provided.

Single mode fibers with antireflective surface structures for high power laser applications

NASA Astrophysics Data System (ADS)

Busse, Lynda E.; Florea, Catalin M.; Shaw, L. Brandon; Aggarwal, Ishwar D.; Sanghera, Jasbinder S.

2014-03-01

We present results for increased transmission of ~99.5% in the near-IR through the end faces of silica single mode fibers by creating a random antireflective microstructure etched into the end face of the fiber. We demonstrate high laser damage thresholds for these fibers with AR structured surfaces.

Polymer electrolyte fuel cell mini power unit for portable application

NASA Astrophysics Data System (ADS)

Urbani, F.; Squadrito, G.; Barbera, O.; Giacoppo, G.; Passalacqua, E.; Zerbinati, O.

This paper describes the design, realisation and test of a power unit based on a polymer electrolyte fuel cell, operating at room temperature, for portable application. The device is composed of an home made air breathing fuel cell stack, a metal hydride tank for H 2 supply, a dc-dc converter for power output control and a fan for stack cooling. The stack is composed by 10 cells with an active surface of 25 cm 2 and produces a rated power of 15 W at 6 V and 2 A. The stack successfully runs with end-off fed hydrogen without appreciable performance degradation during the time. The final assembled system is able to generate 12 W at 9.5 V, and power a portable DVD player for 3 h in continuous. The power unit has collected about 100 h of operation without maintenance.

Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

2009-09-27

To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoommore » activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.« less

Triboelectric-Based Transparent Secret Code.

PubMed

Yuan, Zuqing; Du, Xinyu; Li, Nianwu; Yin, Yingying; Cao, Ran; Zhang, Xiuling; Zhao, Shuyu; Niu, Huidan; Jiang, Tao; Xu, Weihua; Wang, Zhong Lin; Li, Congju

2018-04-01

Private and security information for personal identification requires an encrypted tool to extend communication channels between human and machine through a convenient and secure method. Here, a triboelectric-based transparent secret code (TSC) that enables self-powered sensing and information identification simultaneously in a rapid process method is reported. The transparent and hydrophobic TSC can be conformed to any cambered surface due to its high flexibility, which extends the application scenarios greatly. Independent of the power source, the TSC can induce obvious electric signals only by surface contact. This TSC is velocity-dependent and capable of achieving a peak voltage of ≈4 V at a resistance load of 10 MΩ and a sliding speed of 0.1 m s -1 , according to a 2 mm × 20 mm rectangular stripe. The fabricated TSC can maintain its performance after reciprocating rolling for about 5000 times. The applications of TSC as a self-powered code device are demonstrated, and the ordered signals can be recognized through the height of the electric peaks, which can be further transferred into specific information by the processing program. The designed TSC has great potential in personal identification, commodity circulation, valuables management, and security defense applications.

Electrohydrodynamic behavior of water droplets on a horizontal super hydrophobic surface and its self-cleaning application

NASA Astrophysics Data System (ADS)

Li, Jian; Wei, Yuan; Huang, Zhengyong; Wang, Feipeng; Yan, Xinzhu; Wu, Zhuolin

2017-05-01

Moisture is a significant factor that affects the insulation performance of outdoor high-voltage insulators in power systems. Accumulation of water droplets on insulators causes severe problems such as flashover of insulators and power outage. In this study, we develop a method to fabricate a micro/nano hierarchical super hydrophobic surface. The as-prepared super hydrophobic surface exhibits a water contact angle (WCA) of 160.4 ± 2°, slide angle (SA) less than 1° and surface free energy (SFE) of 5.99 mJ/m2. We investigated the electrohydropdynamic behavior of water droplet on a horizontal super hydrophobic surface compared with hydrophobic RTV silicone rubber surface which was widely used as anti-pollution coating or shed material of composite insulator. Results show that water droplet tended to a self-propelled motion on the super hydrophobic surface while it tended to elongate and break up on the RTV surface. The micro/nano hierarchical surface structure and chemical components with low surface free energy of the super hydrophobic surface jointly contributed to the reduction of skin fraction drag and subsequently made it possible for the motion of water droplet driven by electric field. Furthermore, the self-propelled motion of water droplets could also sweep away contaminations along its moving trace, which provides super hydrophobic surface a promising anti-pollution prospect in power systems.

Commercialization of biomass projects: A case study of the design, development, and application of a biomass gasifier to a large retrofit market

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woerner, W.L.

1994-12-31

The steam production potential of older biomass-fired boilers currently in operation may be significantly increased through the application of a commercially available gasifier. A large percentage of boiler systems in lumber mills and similar applications were initially designed to generate steam through convection heat transfer, and have been horse power rated at approximately 7 to 10 square feet of heating surface to the horse power. This paper deals with the before and after performance characteristics of the first gasifier retrofit installation based on an AED designed unit currently commercially available.

Automation of temperature control for large-array microwave surface applicators.

PubMed

Zhou, L; Fessenden, P

1993-01-01

An adaptive temperature control system has been developed for the microstrip antenna array applicators used for large area superficial hyperthermia. A recursive algorithm which allows rapid power updating even for large antenna arrays and accounts for coupling between neighbouring antennas has been developed, based on a first-order difference equation model. Surface temperatures from the centre of each antenna element are the primary feedback information. Also used are temperatures from additional surface probes placed within the treatment field to protect locations vulnerable to excessive temperatures. In addition, temperatures at depth are observed by mappers and utilized to restrain power to reduce treatment-related complications. Experiments on a tissue-equivalent phantom capable of dynamic differential cooling have successfully verified this temperature control system. The results with the 25 (5 x 5) antenna array have demonstrated that during dynamic water cooling changes and other experimentally simulated disturbances, the controlled temperatures converge to desired temperature patterns with a precision close to the resolution of the thermometry system (0.1 degree C).

CO2 lasers and applications II; Proceedings of the Third European Congress on Optics, The Hague, Netherlands, Mar. 12-14, 1990

NASA Technical Reports Server (NTRS)

Opower, Hans (Editor)

1990-01-01

Recent advances in CO2 laser technology and its applications are examined. Topics discussed include the excitation of CO2 lasers by microwave discharge, a compact RF-excited 12-kW CO2 laser, a robotic laser for three-dimensional cutting and welding, three-dimensional CO2-laser material processing with gantry machine systems, and a comparison of hollow metallic waveguides and optical fibers for transmitting CO2-laser radiation. Consideration is given to an aerodynamic window with a pump cavity and a supersonic jet, cutting and welding Al using a high-repetition-rate pulsed CO2 laser, speckle reduction in CO2 heterodyne laser radar systems, high-power-laser float-zone crystal growth, melt dynamics in surface processing with laser radiation, laser hardfacing, surface melting of AlSi10Mg with CO2 laser radiation, material processing with Cu-vapor lasers, light-induced flow at a metal surface, and absorption measurements in high-power CW CO2-laser processing of materials.

Electrochemical Ultracapacitors Using Graphitic Nanostacks

NASA Technical Reports Server (NTRS)

Marotta, Christopher

2012-01-01

Electrochemical ultracapacitors (ECs) have been developed using graphitic nanostacks as the electrode material. The advantages of this technology will be the reduction of device size due to superior power densities and relative powers compared to traditional activated carbon electrodes. External testing showed that these materials display reduced discharge response times compared to state-of-the-art materials. Such applications are advantageous for pulsed power applications such as burst communications (satellites, cell phones), electromechanical actuators, and battery load leveling in electric vehicles. These carbon nanostructures are highly conductive and offer an ordered mesopore network. These attributes will provide more complete electrolyte wetting, and faster release of stored charge compared to activated carbon. Electrochemical capacitor (EC) electrode materials were developed using commercially available nanomaterials and modifying them to exploit their energy storage properties. These materials would be an improvement over current ECs that employ activated carbon as the electrode material. Commercially available graphite nanofibers (GNFs) are used as precursor materials for the synthesis of graphitic nanostacks (GNSs). These materials offer much greater surface area than graphite flakes. Additionally, these materials offer a superior electrical conductivity and a greater average pore size compared to activated carbon electrodes. The state of the art in EC development uses activated carbon (AC) as the electrode material. AC has a high surface area, but its small average pore size inhibits electrolyte ingress/egress. Additionally, AC has a higher resistivity, which generates parasitic heating in high-power applications. This work focuses on fabricating EC from carbon that has a very different structure by increasing the surface area of the GNF by intercalation or exfoliation of the graphitic basal planes. Additionally, various functionalities to the GNS surface will be added that can exhibit pseudocapacitance. This pseudocapacitance exhibits faradaic (charge transfer) properties that can further increase the overall relative and volumetric capacitance of the material. A process is also proposed to use GNF as a precursor material to fabricate GNS that will be used as EC electrodes. This results in much better electrical conductivity than activated carbon. This is advantageous for high-pulsed-power applications to reduce parasitic heating. Larger average pore size allows more complete electrolyte wetting (faster charge transfer kinetics). These properties contribute to a lowered equivalent series resistance (ESR), increased specific power, shorter charging times, and decreased parasitic heating. The high density of basal plane edges provides nucleation sites for activation (addition of hydrophilic functional groups) that facilitate electrolyte wetting, and will contribute to pseudocapacitance.

Surface and interface sciences of Li-ion batteries. -Research progress in electrode-electrolyte interface-

NASA Astrophysics Data System (ADS)

Minato, Taketoshi; Abe, Takeshi

2017-12-01

The application potential of Li-ion batteries is growing as demand increases in different fields at various stages in energy systems, in addition to their conventional role as power sources for portable devices. In particular, applications in electric vehicles and renewable energy storage are increasing for Li-ion batteries. For these applications, improvements in battery performance are necessary. The Li-ion battery produces and stores electric power from the electrochemical redox reactions between the electrode materials. The interface between the electrodes and electrolyte strongly affects the battery performance because the charge transfer causing the electrode redox reaction begins at this interface. Understanding of the surface structure, electronic structure, and chemical reactions at the electrode-electrolyte interface is necessary to improve battery performance. However, the interface is located between the electrode and electrolyte materials, hindering the experimental analysis of the interface; thus, the physical properties and chemical processes have remained poorly understood until recently. Investigations of the physical properties and chemical processes at the interface have been performed using advanced surface science techniques. In this review, current knowledge and future research prospects regarding the electrode-electrolyte interface are described for the further development of Li-ion batteries.

Study and development of 22 kW peak power fiber coupled short pulse Nd:YAG laser for cleaning applications

NASA Astrophysics Data System (ADS)

Choubey, Ambar; Vishwakarma, S. C.; Vachhani, D. M.; Singh, Ravindra; Misra, Pushkar; Jain, R. K.; Arya, R.; Upadhyaya, B. N.; Oak, S. M.

2014-11-01

Free running short pulse Nd:YAG laser of microsecond pulse duration and high peak power has a unique capability to ablate material from the surface without heat propagation into the bulk. Applications of short pulse Nd:YAG lasers include cleaning and restoration of marble, stones, and a variety of metals for conservation. A study on the development of high peak power short pulses from Nd:YAG laser along with its cleaning and conservation applications has been performed. A pulse energy of 1.25 J with 55 μs pulse duration and a maximum peak power of 22 kW has been achieved. Laser beam has an M2 value of ~28 and a pulse-to-pulse stability of ±2.5%. A lower value of M2 means a better beam quality of the laser in multimode operation. A top hat spatial profile of the laser beam was achieved at the exit end of 200 μm core diameter optical fiber, which is desirable for uniform cleaning. This laser system has been evaluated for efficient cleaning of surface contaminations on marble, zircaloy, and inconel materials for conservation with cleaning efficiency as high as 98%. Laser's cleaning quality and efficiency have been analysed by using a microscope, a scanning electron microscope (SEM), and X-ray photon spectroscopy (XPS) measurements.

Fission Surface Power Systems (FSPS) Project Final Report for the Exploration Technology Development Program (ETDP): Fission Surface Power, Transition Face to Face

NASA Technical Reports Server (NTRS)

Palac, Donald T.

2011-01-01

The Fission Surface Power Systems Project became part of the ETDP on October 1, 2008. Its goal was to demonstrate fission power system technology readiness in an operationally relevant environment, while providing data on fission system characteristics pertinent to the use of a fission power system on planetary surfaces. During fiscal years 08 to 10, the FSPS project activities were dominated by hardware demonstrations of component technologies, to verify their readiness for inclusion in the fission surface power system. These Pathfinders demonstrated multi-kWe Stirling power conversion operating with heat delivered via liquid metal NaK, composite Ti/H2O heat pipe radiator panel operations at 400 K input water temperature, no-moving-part electromagnetic liquid metal pump operation with NaK at flight-like temperatures, and subscale performance of an electric resistance reactor simulator capable of reproducing characteristics of a nuclear reactor for the purpose of system-level testing, and a longer list of component technologies included in the attached report. Based on the successful conclusion of Pathfinder testing, work began in 2010 on design and development of the Technology Demonstration Unit (TDU), a full-scale 1/4 power system-level non-nuclear assembly of a reactor simulator, power conversion, heat rejection, instrumentation and controls, and power management and distribution. The TDU will be developed and fabricated during fiscal years 11 and 12, culminating in initial testing with water cooling replacing the heat rejection system in 2012, and complete testing of the full TDU by the end of 2014. Due to its importance for Mars exploration, potential applicability to missions preceding Mars missions, and readiness for an early system-level demonstration, the Enabling Technology Development and Demonstration program is currently planning to continue the project as the Fission Power Systems project, including emphasis on the TDU completion and testing.

Design Development Analyses in Support of a Heatpipe-Brayton Cycle Heat Exchanger

NASA Technical Reports Server (NTRS)

Steeve, Brian E.; Kapernick, Richard J.

2004-01-01

One of the power systems under consideration for nuclear electric propulsion or as a planetary surface power source is a heatpipe-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the heatpipes to the Brayton gas via a heat exchanger attached to the heatpipes. This paper discusses the fluid, thermal and structural analyses that were performed in support of the design of the heat exchanger to be tested in the SAFE-100 experimental program at the Marshall Space Flight Center: An important consideration throughout the design development of the heat exchanger w its capability to be utilized for higher power and temperature applications. This paper also discusses this aspect of the design and presents designs for specific applications that are under consideration.

Development and Utilization of Space Fission Power Systems

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Mason, Lee S.; Palac, Donald T.; Harlow, Scott E.

2009-01-01

Space fission power systems could enable advanced civilian space missions. Terrestrially, thousands of fission systems have been operated since 1942. In addition, the US flew a space fission system in 1965, and the former Soviet Union flew 33 such systems prior to the end of the Cold War. Modern design and development practices, coupled with 65 years of experience with terrestrial reactors, could enable the affordable development of space fission power systems for near-term planetary surface applications.

Development and Utilization of Space Fission Power Systems

NASA Technical Reports Server (NTRS)

Houts, Michael; Mason, Lee S.; Palac, Donald T.; Harlow, Scott E.

2008-01-01

Space fission power systems could enable advanced civilian space missions. Terrestrially, thousands of fission systems have been operated since 1942. In addition, the US flew a space fission system in 1965, and the former Soviet Union flew 33 such systems prior to the end of the Cold War. Modern design and development practices, coupled with 65 years of experience with terrestrial reactors, could enable the affordable development of space fission power systems for near-term planetary surface applications.

78 FR 34431 - Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Point...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-07

...EPA is proposing a regulation that would strengthen the controls on discharges from certain steam electric power plants by revising technology-based effluent limitations guidelines and standards for the steam electric power generating point source category. Steam electric power plants alone contribute 50-60 percent of all toxic pollutants discharged to surface waters by all industrial categories currently regulated in the United States under the Clean Water Act. Furthermore, power plant discharges to surface waters are expected to increase as pollutants are increasingly captured by air pollution controls and transferred to wastewater discharges. This proposal, if implemented, would reduce the amount of toxic metals and other pollutants discharged to surface waters from power plants. EPA is considering several regulatory options in this rulemaking and has identified four preferred alternatives for regulation of discharges from existing sources. These four preferred alternatives differ with respect to the scope of requirements that would be applicable to existing discharges of pollutants found in two wastestreams generated at power plants. EPA estimates that the preferred options for this proposed rule would annually reduce pollutant discharges by 0.47 billion to 2.62 billion pounds, reduce water use by 50 billion to 103 billion gallons, cost $185 million to $954 million, and would be economically achievable.

Power-Production Diagnostic Tools for Low-Density Wind Farms with Applications to Wake Steering

NASA Astrophysics Data System (ADS)

Takle, E. S.; Herzmann, D.; Rajewski, D. A.; Lundquist, J. K.; Rhodes, M. E.

2016-12-01

Hansen (2011) provided guidelines for wind farm wake analysis with applications to "high density" wind farms (where average distance between turbines is less than ten times rotor diameter). For "low-density" (average distance greater than fifteen times rotor diameter) wind farms, or sections of wind farms we demonstrate simpler sorting and visualization tools that reveal wake interactions and opportunities for wind farm power prediction and wake steering. SCADA data from a segment of a large mid-continent wind farm, together with surface flux measurements and lidar data are subjected to analysis and visualization of wake interactions. A time-history animated visualization of a plan view of power level of individual turbines provides a quick analysis of wake interaction dynamics. Yaw-based sectoral histograms of enhancement/decline of wind speed and power from wind farm reference levels reveals angular width of wake interactions and identifies the turbine(s) responsible for the power reduction. Concurrent surface flux measurements within the wind farm allowed us to evaluate stability influence on wake loss. A one-season climatology is used to identify high-priority candidates for wake steering based on estimated power recovery. Typical clearing prices on the day-ahead market are used to estimate the added value of wake steering. Current research is exploring options for identifying candidate locations for wind farm "build-in" in existing low-density wind farms.

Screen printed passive components for flexible power electronics

NASA Astrophysics Data System (ADS)

Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

2015-10-01

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Screen printed passive components for flexible power electronics

PubMed Central

Ostfeld, Aminy E.; Deckman, Igal; Gaikwad, Abhinav M.; Lochner, Claire M.; Arias, Ana C.

2015-01-01

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components—inductors, capacitors, and resistors—perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application. PMID:26514331

Screen printed passive components for flexible power electronics.

PubMed

Ostfeld, Aminy E; Deckman, Igal; Gaikwad, Abhinav M; Lochner, Claire M; Arias, Ana C

2015-10-30

Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive components-inductors, capacitors, and resistors-perform functions such as filtering, short-term energy storage, and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates, and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Surface charge sensing by altering the phase transition in VO2

NASA Astrophysics Data System (ADS)

Kumar, S.; Esfandyarpour, R.; Davis, R.; Nishi, Y.

2014-08-01

Detection of surface charges has various applications in medicine, electronics, biotechnology, etc. The source of surface charge induction may range from simple charge-polarized molecules like water to complicated proteins. It was recently discovered that surface charge accumulation can alter the temperature at which VO2 undergoes a Mott transition. Here, we deposited polar molecules onto the surface of two-terminal thin-film VO2 lateral devices and monitored the joule-heating-driven Mott transition, or conductance switching. We observed that the power required to induce the conductance switching reduced upon treatment with polar molecules and, using in-situ blackbody-emission direct measurement of local temperature, we show that this reduction in power was accompanied by reduction in the Mott transition temperature. Further evidence suggested that this effect has specificity to the nature of the species used to induce surface charges. Using x-ray absorption spectroscopy, we also show that there is no detectable change in oxidation state of vanadium or structural phase in the bulk of the 40 nm VO2 thin-film even as the phase transition temperature is reduced by up to 20 K by the polar molecules. The ability to alter the phase transition parameters by depositing polar molecules suggests a potential application in sensing surface charges of different origins and this set of results also highlights interesting aspects of the phase transition in VO2.

Continued Investigation of Leakage and Power Loss Test Results for Competing Turbine Engine Seals

NASA Technical Reports Server (NTRS)

Delgado, Irebert R.; Proctor, Margaret P.

2006-01-01

Secondary seal leakage in jet engine applications results in power losses to the engine cycle. Likewise, seal power loss in jet engines not only result in efficiency loss but also increase the heat input into the engine resulting in reduced component lives. Experimental work on labyrinth and annular seals was performed at NASA Glenn Research Center to quantify seal leakage and power loss at various temperatures, seal pressure differentials, and surface speeds. Data from annular and labyrinth seals are compared with previous brush and finger seal test results. Data are also compared to literature. Annular and labyrinth seal leakage rates are 2 to 3 times greater than brush and finger seal rates. Seal leakage decreases with increasing speed but increases with increasing test temperature due to thermal expansion mismatch. Also seal power loss increases with surface speed, seal pressure differential, mass flow rate, and radial clearance. Annular and labyrinth seal power losses were higher than those of brush or finger seal data. The brush seal power loss was 15 to 30 percent lower than annular and labyrinth seal power loss.

Infrastructure for deployment of power systems

NASA Technical Reports Server (NTRS)

Sprouse, Kenneth M.

1991-01-01

A preliminary effort in characterizing the types of stationary lunar power systems which may be considered for emplacement on the lunar surface from the proposed initial 100-kW unit in 2003 to later units ranging in power from 25 to 825 kW is presented. Associated with these power systems are their related infrastructure hardware including: (1) electrical cable, wiring, switchgear, and converters; (2) deployable radiator panels; (3) deployable photovoltaic (PV) panels; (4) heat transfer fluid piping and connection joints; (5) power system instrumentation and control equipment; and (6) interface hardware between lunar surface construction/maintenance equipment and power system. This report: (1) presents estimates of the mass and volumes associated with these power systems and their related infrastructure hardware; (2) provides task breakdown description for emplacing this equipment; (3) gives estimated heat, forces, torques, and alignment tolerances for equipment assembly; and (4) provides other important equipment/machinery requirements where applicable. Packaging options for this equipment will be discussed along with necessary site preparation requirements. Design and analysis issues associated with the final emplacement of this power system hardware are also described.

Design and Build of Reactor Simulator for Fission Surface Power Technology Demonstrator Unit

NASA Technical Reports Server (NTRS)

Godfroy, Thomas; Dickens, Ricky; Houts, Michael; Pearson, Boise; Webster, Kenny; Gibson, Marc; Qualls, Lou; Poston, Dave; Werner, Jim; Radel, Ross

2011-01-01

The Nuclear Systems Team at NASA Marshall Space Flight Center (MSFC) focuses on technology development for state of the art capability in non-nuclear testing of nuclear system and Space Nuclear Power for fission reactor systems for lunar and Mars surface power generation as well as radioisotope power systems for both spacecraft and surface applications. Currently being designed and developed is a reactor simulator (RxSim) for incorporation into the Technology Demonstrator Unit (TDU) for the Fission Surface Power System (FSPS) Program, which is supported by multiple national laboratories and NASA centers. The ultimate purpose of the RxSim is to provide heated NaK to a pair of Stirling engines in the TDU. The RxSim includes many different systems, components, and instrumentation that have been developed at MSFC while working with pumped NaK systems and in partnership with the national laboratories and NASA centers. The main components of the RxSim are a core, a pump, a heat exchanger (to mimic the thermal load of the Stirling engines), and a flow meter for tests at MSFC. When tested at NASA Glenn Research Center (GRC) the heat exchanger will be replaced with a Stirling power conversion engine. Additional components include storage reservoirs, expansion volumes, overflow catch tanks, safety and support hardware, instrumentation (temperature, pressure, flow) for data collection, and power supplies. This paper will discuss the design and current build status of the RxSim for delivery to GRC in early 2012.

Design and Build of Reactor Simulator for Fission Surface Power Technology Demonstrator Unit

NASA Astrophysics Data System (ADS)

Godfroy, T.; Dickens, R.; Houts, M.; Pearson, B.; Webster, K.; Gibson, M.; Qualls, L.; Poston, D.; Werner, J.; Radel, R.

The Nuclear Systems Team at Marshall Space Flight Center (MSFC) focuses on technology development for state of the art capability in non-nuclear testing of nuclear system and Space Nuclear Power for fission reactor systems for lunar and mars surface power generation as well as radioisotope power systems for both spacecraft and surface applications. Currently being designed and developed is a reactor simulator (RxSim) for incorporation into the Technology Demonstrator Unit (TDU) for the Fission Surface Power System (FSPS) Program which is supported by multiple national laboratories and NASA centers. The ultimate purpose of the RxSim is to provide heated NaK to a pair of Stirling engines in the TDU. The RxSim includes many different systems, components, and instrumentation that have been developed at MSFC while working with pumped NaK systems and in partnership with the national laboratories and NASA centers. The main components of the RxSim are a core, a pump, a heat exchanger (to mimic the thermal load of the Stirling engines), and a flow meter when being tested at MSFC. When tested at GRC the heat exchanger will be replaced with a Stirling power conversion engine. Additional components include storage reservoirs, expansion volumes, overflow catch tanks, safety and support hardware, instrumenta- tion (temperature, pressure, flow) data collection, and power supplies. This paper will discuss the design and current build status of the RxSim for delivery to GRC in early 2012.

Influence of power ultrasound application on mass transport and microstructure of orange peel during hot air drying

NASA Astrophysics Data System (ADS)

Ortuño, Carmen; Pérez-Munuera, Isabel; Puig, Ana; Riera, Enrique; Garcia-Perez, J. V.

2010-01-01

Power ultrasound application on convective drying of foodstuffs may be considered an emergent technology. This work deals with the influence of power ultrasound on drying of natural materials addressing the kinetic as well as the product's microstructure. Convective drying kinetics of orange peel slabs (thickness 5.95±0.41 mm) were carried out at 40 ∘C and 1 m/s with (US) and without (AIR) power ultrasound application. A diffusion model considering external resistance to mass transfer was considered to describe drying kinetics. Fresh, US and AIR dried samples were analyzed using Cryo-SEM. Results showed that drying kinetics of orange peel were significantly improved by the application of power ultrasound. From modeling, it was observed a significant (p¡0.05) increase in both mass transfer coefficient and effective moisture diffusivity. The effects on mass transfer properties were confirmed from microestructural observations. In the cuticle surface, the pores were obstructed by wax components scattering, which evidence the ultrasonic effects on the interfaces. The cells of the flavedo were compressed and large intercellular air spaces were generated in the albedo facilitating water transfer through it.

The suppression effect of external magnetic field on the high-power microwave window multipactor phenomenon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xue, E-mail: zhangxue.iecas@yahoo.com; Wang, Yong; Fan, Junjie

2015-02-15

To suppress the surface multipactor phenomenon and improve the transmitting power of the high-power microwave window, the application of external magnetic fields is theoretically analyzed and simulated. A Monte Carlo algorithm is used to track the secondary electron trajectories and study the multipactor scenario on the surface of a cylinder window. It is confirmed that over-resonant magnetic fields (an external magnetic field whose magnitude is slightly greater than that of a resonant magnetic field) will generate a compensating trajectory and collision, which can suppress the secondary electron avalanche. The optimal value of this external magnetic field that will avoid themore » multipactor phenomenon on cylinder windows is discussed.« less

Carbon Redox-Polymer-Gel Hybrid Supercapacitors.

PubMed

Vlad, A; Singh, N; Melinte, S; Gohy, J-F; Ajayan, P M

2016-02-26

Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances.

Study of ultrasonic melt treatment on the quality of horizontal continuously cast Al-1%Si alloy.

PubMed

Li, Xin-Tao; Li, Ting-Ju; Li, Xi-Meng; Jin, Jun-Ze

2006-02-01

The fluctuation of the melt temperature in a tundish was measured during casting and experiments were conducted to investigate the effects of ultrasonic melt treatment on the surface quality and solidification structures of Al-1%Si ingots. The results show that the uniformity of melt temperature was enhanced with the application of ultrasonic melt treatment. When the ultrasonic power is 1,000W, the surface quality was evidently improved and grains of cast ingots were refined. Moreover, EPMA analysis was adopted to study the relationship between the ultrasonic power and boundary segregation of Si element. The result shows that boundary segregation is suppressed with the increase of ultrasonic power and the phenomenon was theoretically interpreted.

Lunar base thermal management/power system analysis and design

NASA Technical Reports Server (NTRS)

Mcghee, Jerry R.

1992-01-01

A compilation of several lunar surface thermal management and power system studies completed under contract and IR&D is presented. The work includes analysis and preliminary design of all major components of an integrated thermal management system, including loads determination, active internal acquisition and transport equipment, external transport systems (active and passive), passive insulation, solar shielding, and a range of lunar surface radiator concepts. Several computer codes were utilized in support of this study, including RADSIM to calculate radiation exchange factors and view factors, RADIATOR (developed in-house) for heat rejection system sizing and performance analysis over a lunar day, SURPWER for power system sizing, and CRYSTORE for cryogenic system performance predictions. Although much of the work was performed in support of lunar rover studies, any or all of the results can be applied to a range of surface applications. Output data include thermal loads summaries, subsystem performance data, mass, and volume estimates (where applicable), integrated and worst-case lunar day radiator size/mass and effective sink temperatures for several concepts (shielded and unshielded), and external transport system performance estimates for both single and two-phase (heat pumped) transport loops. Several advanced radiator concepts are presented, along with brief assessments of possible system benefits and potential drawbacks. System point designs are presented for several cases, executed in support of the contract and IR&D studies, although the parametric nature of the analysis is stressed to illustrate applicability of the analysis procedure to a wide variety of lunar surface systems. The reference configuration(s) derived from the various studies will be presented along with supporting criteria. A preliminary design will also be presented for the reference basing scenario, including qualitative data regarding TPS concerns and issues.

Self-mixing interferometry in vertical-cavity surface-emitting lasers for nanomechanical cantilever sensing

NASA Astrophysics Data System (ADS)

Larsson, David; Greve, Anders; Hvam, Jørn M.; Boisen, Anja; Yvind, Kresten

2009-03-01

We have experimentally investigated self-mixing interference produced by the feedback of light from a polymer micrometer-sized cantilever into a vertical-cavity surface-emitting laser for sensing applications. In particular we have investigated how the visibility of the optical output power and the junction voltage depends on the laser injection current and the distance to the cantilever. The highest power visibility obtained from cantilevers without reflective coatings was ˜60%, resulting in a very high sensitivity of 45 mV/nm with a noise floor below 1.2 mV. Different detection schemes are discussed.

Characteristics of Nd:YAG sculptured contact probes after prolonged laser application.

PubMed

Barroso, E G; Haklin, M F; Staren, E D

1995-01-01

This study analyzed the functional and structural characteristics of cone, hemisphere, and modified sculptured contact fibers (1,000 microns) after 1 hour of continuous Nd:YAG laser application. Continuous laser application was performed on live porcine tissue using 20 watts of power. The fiber's appearance under a microscope as well as the power output was recorded after 0, 5, 10, 20, 30, 45, and 60 minutes of continuous laser application. (N = 3 for each fiber). At time 0, all fibers transmitted from 49 to 56% of the initial 20 watts (W); power transmission decreased to less than 9% relative power transmission after 20 minutes and then plateaued. The fibers exhibited severe distortion and carbonization of the surface where laser had been applied with evidence of quartz melting and shattering after only 10 minutes. By 30 minutes of laser application, all three fibers were fractured and essentially indistinguishable from one another; moreover, the fibers exhibited similar power transmission, and cutting and coagulation activity, as determined by a panel of independent, double-blinded surgeons. These data lead us to conclude that 1) Nd:YAG contact laser effects result from thermal heating of the fiber tip with subsequent tissue injury, 2) the unique structural configuration of the fiber's sculptured tip are lost after several minutes of laser application without appreciable change in functional integrity, and 3) fibers may be manually fractured allowing for multiple uses without significant sacrifice of power transmission or surgical utility.

A microelectronics approach for the ROSETTA surface science package

NASA Technical Reports Server (NTRS)

Sandau, Rainer (Editor); Alkalaj, Leon

1996-01-01

In relation to the Rosetta surface science package, the benefits of the application of advanced microelectronics packaging technologies and other output from the Mars environmental survey (MESUR) integrated microelectronics study are reported on. The surface science package will be designed to operate for tens of hours. Its limited mass and power consumption make necessary a highly integrated design with all the instruments and subunits operated from a centralized control and information management subsystem.

High-surface-area, dual-function oxygen electrocatalysts for space power applications

NASA Technical Reports Server (NTRS)

Ham, David O.; Moniz, Gary; Taylor, E. Jennings

1987-01-01

The processes of hydration/dehydration and carbonation/decarbonation are investigated as an approach to provide higher surface area mixed metal oxides that are more active electrochemically. These materials are candidates for use as electrocatalysts and electrocatalyst supports for alkaline electrolyzers and fuel cells. For the case of the perovskite, LaCoO3 , higher surface areas were achieved with no change in structure and a more active oxygen electrocatalyst.

Selectivity/Specificity Improvement Strategies in Surface-Enhanced Raman Spectroscopy Analysis

PubMed Central

Wang, Feng; Cao, Shiyu; Yan, Ruxia; Wang, Zewei; Wang, Dan; Yang, Haifeng

2017-01-01

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for the discrimination, identification, and potential quantification of certain compounds/organisms. However, its real application is challenging due to the multiple interference from the complicated detection matrix. Therefore, selective/specific detection is crucial for the real application of SERS technique. We summarize in this review five selective/specific detection techniques (chemical reaction, antibody, aptamer, molecularly imprinted polymers and microfluidics), which can be applied for the rapid and reliable selective/specific detection when coupled with SERS technique. PMID:29160798

Electric Power System Technology Options for Lunar Surface Missions

NASA Technical Reports Server (NTRS)

Kerslake, Thomas W.

2005-01-01

In 2004, the President announced a 'Vision for Space Exploration' that is bold and forward-thinking, yet practical and responsible. The vision explores answers to longstanding questions of importance to science and society and will develop revolutionary technologies and capabilities for the future, while maintaining good stewardship of taxpayer dollars. One crucial technology area enabling all space exploration is electric power systems. In this paper, the author evaluates surface power technology options in order to identify leading candidate technologies that will accomplish lunar design reference mission three (LDRM-3). LDRM-3 mission consists of multiple, 90-day missions to the lunar South Pole with 4-person crews starting in the year 2020. Top-level power requirements included a nominal 50 kW continuous habitat power over a 5-year lifetime with back-up or redundant emergency power provisions and a nominal 2-kW, 2-person unpressurized rover. To help direct NASA's technology investment strategy, this lunar surface power technology evaluation assessed many figures of merit including: current technology readiness levels (TRLs), potential to advance to TRL 6 by 2014, effectiveness of the technology to meet the mission requirements in the specified time, mass, stowed volume, deployed area, complexity, required special ground facilities, safety, reliability/redundancy, strength of industrial base, applicability to other LDRM-3 elements, extensibility to Mars missions, costs, and risks. For the 50-kW habitat module, dozens of nuclear, radioisotope and solar power technologies were down-selected to a nuclear fission heat source with Brayton, Stirling or thermoelectric power conversion options. Preferred energy storage technologies included lithium-ion battery and Proton Exchange Membrane (PEM) Regenerative Fuel Cells (RFC). Several AC and DC power management and distribution architectures and component technologies were defined consistent with the preferred habitat power generation technology option and the overall lunar surface mission. For rover power, more than 20 technology options were down-selected to radioisotope Stirling, liquid lithium-ion battery, PEM RFC, or primary fuel cell options. The author discusses various conclusions that can be drawn from the findings of this surface power technologies evaluation.

Power System Mass Analysis for Hydrogen Reduction Oxygen Production on the Lunar Surface

NASA Technical Reports Server (NTRS)

Colozza, Anthony J.

2009-01-01

The production of oxygen from the lunar regolith requires both thermal and electrical power in roughly similar proportions. This unique power requirement is unlike most applications on the lunar surface. To efficiently meet these requirements, both solar PV array and solar concentrator systems were evaluated. The mass of various types of photovoltaic and concentrator based systems were calculated to determine the type of power system that provided the highest specific power. These were compared over a range of oxygen production rates. Also a hybrid type power system was also considered. This system utilized a photovoltaic array to produce the electrical power and a concentrator to provide the thermal power. For a single source system the three systems with the highest specific power were a flexible concentrator/Stirling engine system, a rigid concentrator/Stirling engine system and a tracking triple junction solar array system. These systems had specific power values of 43, 34, and 33 W/kg, respectively. The hybrid power system provided much higher specific power values then the single source systems. The best hybrid combinations were the triple junction solar array with the flexible concentrator and the rigid concentrator. These systems had a specific power of 81 and 68 W/kg, respectively.

Planetary benchmarks. [structural design criteria for radar reference devices on planetary surfaces

NASA Technical Reports Server (NTRS)

Uphoff, C.; Staehle, R.; Kobrick, M.; Jurgens, R.; Price, H.; Slade, M.; Sonnabend, D.

1978-01-01

Design criteria and technology requirements for a system of radar reference devices to be fixed to the surfaces of the inner planets are discussed. Offshoot applications include the use of radar corner reflectors as landing beacons on the planetary surfaces and some deep space applications that may yield a greatly enhanced knowledge of the gravitational and electromagnetic structure of the solar system. Passive retroreflectors with dimensions of about 4 meters and weighing about 10 kg are feasible for use with orbiting radar at Venus and Mars. Earth-based observation of passive reflectors, however, would require very large and complex structures to be delivered to the surfaces. For Earth-based measurements, surface transponders offer a distinct advantage in accuracy over passive reflectors. A conceptual design for a high temperature transponder is presented. The design appears feasible for the Venus surface using existing electronics and power components.

Molten Boron Phase-Change Thermal Energy Storage: Containment and Applicability to Microsatellites (Draft)

DTIC Science & Technology

2011-06-01

technologies, including high temperature thermal insulation and thermal to electric power conversion, have been evaluated, and a preliminary design...support technologies, including high temperature thermal insulation and thermal to electric power conversion, have been evaluated, and a preliminary...vacuum gap with low emissivity surfaces on either side as the first insulating layer.11 D. Electrical Energy Conversion There are a wide variety

Low-Voltage Organic Single-Crystal Field-Effect Transistor with Steep Subthreshold Slope.

PubMed

Yang, Fangxu; Sun, Lingjie; Han, Jiangli; Li, Baili; Yu, Xi; Zhang, Xiaotao; Ren, Xiaochen; Hu, Wenping

2018-03-06

Anodization is a promising technique to form high- k dielectrics for low-power organic field-effect transistor (OFET) applications. However, the surface quality of the dielectric, which is mainly inherited from the metal electrode, can be improved further than other fabrication techniques, such as sol-gel. In this study, we applied the template stripping method to fabricate a low-power single-crystalline OFET based on the anodized AlO x dielectric. We found that the template stripping method largely improves the surface roughness of the deposited Al and allows for the formation of a high-quality AlO x high- k dielectric by anodization. The ultraflat AlO x /SAM dielectric combined with a single-crystal 2,6-diphenylanthracene (DPA) semiconductor produced a nearly defect-free interface with a steep subthreshold swing (SS) of 66 mV/decade. The current device is a promising candidate for future ultralow-power applications. Other than metal deposition, template stripping could provide a general approach to improve thin-film quality for many other types of materials and processes.

A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

NASA Astrophysics Data System (ADS)

Duan, Xin; Chen, Xing; Zhou, Lin

2016-12-01

A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

SRF Cavity Surface Topography Characterization Using Replica Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. Xu, M.J. Kelley, C.E. Reece

2012-07-01

To better understand the roll of topography on SRF cavity performance, we seek to obtain detailed topographic information from the curved practical cavity surfaces. Replicas taken from a cavity interior surface provide internal surface molds for fine Atomic Force Microscopy (AFM) and stylus profilometry. In this study, we confirm the replica resolution both on surface local defects such as grain boundary and etching pits and compare the surface uniform roughness with the aid of Power Spectral Density (PSD) where we can statistically obtain roughness parameters at different scales. A series of sampling locations are at the same magnetic field chosenmore » at the same latitude on a single cell cavity to confirm the uniformity. Another series of sampling locations at different magnetic field amplitudes are chosen for this replica on the same cavity for later power loss calculation. We also show that application of the replica followed by rinsing does not adversely affect the cavity performance.« less

Economic contribution of 'artificial upwelling' mariculture to sea-thermal power generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roels, O.A.

1976-07-01

Deep-sea water has two valuable properties: it is uniformly cold and, compared to surface water, it is rich in nutrients such as nitrate and phosphate which are necessary for plant growth. In tropical and subtropical areas, the temperature difference between the warm surface water and the cold deep water can be used for sea-thermal power generation or other cooling applications such as air-conditioning, ice-making, desalination, and cooling of refineries, power plants, etc. Once the deep water is brought to the surface, utilization of both the cold temperature and the nutrient content is likely to be more advantageous than the usemore » of only one of them. Claude demonstrated the technical feasibility of sea-thermal power generation in Cuba in 1930. The technical feasibility of artificial upwelling mariculture in the St. Croix installation has been demonstrated. Results to date demonstrate that the gross sales value of the potential mariculture yield from a given volume of deep-sea water is many times that of the sales value of the power which can be generated by the Claude process from the same volume of deep water. Utilizing both the nutrient content and the cold temperature of the deep water may therefore make sea-thermal power generation economically feasible.« less

Shear-horizontal surface acoustic wave phononic device with high density filling material for ultra-low power sensing applications

NASA Astrophysics Data System (ADS)

Richardson, M.; Sankaranarayanan, S. K. R. S.; Bhethanabotla, V. R.

2014-06-01

Finite element simulations of a phononic shear-horizontal surface acoustic wave (SAW) sensor based on ST 90°-X Quartz reveal a dramatic reduction in power consumption. The phononic sensor is realized by artificially structuring the delay path to form an acoustic meta-material comprised of a periodic microcavity array incorporating high-density materials such as tantalum or tungsten. Constructive interference of the scattered and secondary reflected waves at every microcavity interface leads to acoustic energy confinement in the high-density regions translating into reduced power loss. Tantalum filled cavities show the best performance while tungsten inclusions create a phononic bandgap. Based on our simulation results, SAW devices with tantalum filled microcavities were fabricated and shown to significantly decrease insertion loss. Our findings offer encouraging prospects for designing low power, highly sensitive portable biosensors.

Application of the mobility power flow approach to structural response from distributed loading

NASA Technical Reports Server (NTRS)

Cuschieri, J. M.

1988-01-01

The problem of the vibration power flow through coupled substructures when one of the substructures is subjected to a distributed load is addressed. In all the work performed thus far, point force excitation was considered. However, in the case of the excitation of an aircraft fuselage, distributed loading on the whole surface of a panel can be as important as the excitation from directly applied forces at defined locations on the structures. Thus using a mobility power flow approach, expressions are developed for the transmission of vibrational power between two coupled plate substructures in an L configuration, with one of the surfaces of one of the plate substructures being subjected to a distributed load. The types of distributed loads that are considered are a force load with an arbitrary function in space and a distributed load similar to that from acoustic excitation.

Micro-channel-based high specific power lithium target

NASA Astrophysics Data System (ADS)

Mastinu, P.; Martın-Hernández, G.; Praena, J.; Gramegna, F.; Prete, G.; Agostini, P.; Aiello, A.; Phoenix, B.

2016-11-01

A micro-channel-based heat sink has been produced and tested. The device has been developed to be used as a Lithium target for the LENOS (Legnaro Neutron Source) facility and for the production of radioisotope. Nevertheless, applications of such device can span on many areas: cooling of electronic devices, diode laser array, automotive applications etc. The target has been tested using a proton beam of 2.8MeV energy and delivering total power shots from 100W to 1500W with beam spots varying from 5mm2 to 19mm2. Since the target has been designed to be used with a thin deposit of lithium and since lithium is a low-melting-point material, we have measured that, for such application, a specific power of about 3kW/cm2 can be delivered to the target, keeping the maximum surface temperature not exceeding 150° C.

Complex amine-based reagents

NASA Astrophysics Data System (ADS)

Suslov, S. Yu.; Kirilina, A. V.; Sergeev, I. A.; Zezyulya, T. V.; Sokolova, E. A.; Eremina, E. V.; Timofeev, N. V.

2017-03-01

Amines for a long time have been applied to maintaining water chemistry conditions (WCC) at power plants. However, making use of complex reagents that are the mixture of neutralizing and the filmforming amines, which may also contain other organic components, causes many disputes. This is mainly due to lack of reliable information about these components. The protective properties of any amine with regard to metal surfaces depend on several factors, which are considered in this article. The results of applying complex reagents to the protection of heating surfaces in industrial conditions and estimated behavior forecasts for various reagents under maintaining WCC on heat-recovery boilers with different thermal circuits are presented. The case of a two-drum heat-recovery boiler with in-line drums was used as an example, for which we present the calculated pH values for various brands of reagents under the same conditions. Work with different reagent brands and its analysis enabled us to derive a composition best suitable for the conditions of their practical applications in heat-recovery boilers at different pressures. Testing the new amine reagent performed at a CCPP power unit shows that this reagent is an adequate base for further development of reagents based on amine compounds. An example of testing a complex reagent is shown created with the participation of the authors within the framework the program of import substitution and its possible use is demonstrated for maintaining WCC of power-generating units of combined-cycle power plants (CCPP) and TPP. The compliance of the employed reagents with the standards of water chemistry conditions and protection of heating surfaces were assessed. The application of amine-containing reagents at power-generating units of TPP makes it possible to solve complex problems aimed at ensuring the sparing cleaning of heating surfaces from deposits and the implementation of conservation and management of water chemistry condition on the TPP equipment.

Effect of Bauxite addition on Adhesion Strength and Surface Roughness of Fly ash based Plasma Sprayed Coatings

NASA Astrophysics Data System (ADS)

Bhuyan, S. K.; Samal, S.; Pattnaik, D.; Sahu, A.; Swain, B.; Thiyagarajan, T. K.; Mishra, S. C.

2018-03-01

The environment is being contaminated with advancement of new technology, day by day. One of the primary sources for this contamination is the industrial waste. Industrialization is the prime reason behind the prosperity of any country to meet the materialistic demand. To run the industries, a huge amount of (electric) power is needed and hence need for thermal power plants to serve the purpose. In present scenario, coal fired thermal power plants are set up which generates a huge quantity of Fly ash. Consumption of industrial waste (Fly ash), continually a major concern for human race. In recent years, fly ash is being utilized for various purposes i.e. making bricks, mine reclamation, production of cements etc. The presence of Silica and Alumina in fly ash makes it useful for thermal barrier applications also. The plasma spray technology has the advantage of being able to process any types of metal/ceramic mineral, low-grade-ore minerals etc. to make value-added products and also to deposit ceramics, metals and a combination of these to deposit composite coatings with desired microstructure and required properties on a range of substrate materials. The present work focuses on utilization of fly ash mixing with bauxite (ore mineral) for a high valued application. Fly ash with 10 and 20% bauxite addition is used to deposit plasma spray overlay coatings at different power levels (10-20kW) on aluminum and mild steel substrates. Adhesion strength and surface roughness of the coatings are evaluated. Phase composition analysis of the coatings were done using X-ray diffraction analysis. Surface morphology of the coatings was studied using a scanning electron microscope (SEM). Maximum adhesion strength of 4.924 MPa is obtained for the composition fly ash and bauxite (10%), coated on mild steel at 16kW torch power level. The surface roughness (Ra) of the coatings is found to vary between 10.0102 to 17.2341 micron.

Regenerative Fuel Cell Power Systems for Lunar and Martian Surface Exploration

NASA Technical Reports Server (NTRS)

Guzik, Monica C.; Jakupca, Ian J.; Gilligan, Ryan P.; Bennett, William R.; Smith, Phillip J.; Fincannon, James

2017-01-01

This paper presents the preliminary results of a recent National Aeronautics and Space Administration (NASA) study funded under the Advanced Exploration Systems (AES) Modular Power Systems (AMPS) project. This study evaluated multiple surface locations on both the Moon and Mars, with the goal of establishing a common approach towards technology development and system design for surface power systems that use Regenerative Fuel Cell (RFC) energy storage methods. One RFC design may not be applicable to all surface locations; however, AMPS seeks to find a unified architecture, or series of architectures, that leverages a single development approach to answer the technology need for RFC systems. Early system trades were performed to select the most effective fuel cell and electrolyzer architectures based on current state-of-the-art technology, whereas later trades will establish a detailed system design to enable a near-term ground (non-flight) demonstration. This paper focuses on the initial trade studies, presents the selected fuel cell and electrolyzer architectures for follow-on system design studies, and suggests areas for further technology investment.

Field enhancement in plasmonic nanostructures

NASA Astrophysics Data System (ADS)

Piltan, Shiva; Sievenpiper, Dan

2018-05-01

Efficient generation of charge carriers from a metallic surface is a critical challenge in a wide variety of applications including vacuum microelectronics and photo-electrochemical devices. Replacing semiconductors with vacuum/gas as the medium of electron transport offers superior speed, power, and robustness to radiation and temperature. We propose a metallic resonant surface combining optical and electrical excitations of electrons and significantly reducing powers required using plasmon-induced enhancement of confined electric field. The properties of the device are modeled using the exact solution of the time-dependent Schrödinger equation at the barrier. Measurement results exhibit strong agreement with an analytical solution, and allow us to extract the field enhancement factor at the surface. Significant photocurrents are observed using combination of {{W}} {{{c}}{{m}}}-2 optical power and 10 V DC excitation on the surface. The model suggests optical field enhancement of 3 orders of magnitude at the metal interface due to plasmonic resonance. This simple planar structure provides valuable evidence on the electron emission mechanisms involved and it can be used for implementation of semiconductor compatible vacuum devices.

Lightweight Modular Instrumentation for Planetary Applications

NASA Technical Reports Server (NTRS)

Joshi, P. B.

1993-01-01

An instrumentation, called Space Active Modular Materials ExperimentS (SAMMES), is developed for monitoring the spacecraft environment and for accurately measuring the degradation of space materials in low earth orbit (LEO). The SAMMES architecture concept can be extended to instrumentation for planetary exploration, both on spacecraft and in situ. The operating environment for planetary application will be substantially different, with temperature extremes and harsh solar wind and cosmic ray flux on lunar surfaces and temperature extremes and high winds on venusian and Martian surfaces. Moreover, instruments for surface deployment, which will be packaged in a small lander/rover (as in MESUR, for example), must be extremely compact with ultralow power and weight. With these requirements in mind, the SAMMES concept was extended to a sensor/instrumentation scheme for the lunar and Martian surface environment.

Surface improvement and biocompatibility of TiAl 24Nb 10 intermetallic alloy using rf plasma nitriding

NASA Astrophysics Data System (ADS)

Abd El-Rahman, A. M.; Maitz, M. F.; Kassem, M. A.; El-Hossary, F. M.; Prokert, F.; Reuther, H.; Pham, M. T.; Richter, E.

2007-09-01

The present work describes the surface improvement and biocompatibility of TiAl 24Nb 10 intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to formation of a thin modified layer which is composed of titanium nitride in the alloy surface. Moreover, all modified layers were tested for their sustainability as a biocompatible material. Concerning the application area of biocompatibility, the present treated alloy show good surface properties especially for the nitrided alloy at low plasma power of 400 W.

Carbon-Nanotube-Based Electrochemical Double-Layer Capacitor Technologies for Spaceflight Applications

NASA Technical Reports Server (NTRS)

Arepalli, S.; Fireman, H.; Huffman, C.; Maloney, P.; Nikolaev, P.; Yowell, L.; Kim, K.; Kohl, P. A.; Higgins, C. D.; Turano, S. P.

2005-01-01

Electrochemical double-layer capacitors, or supercapacitors, have tremendous potential as high-power energy sources for use in low-weight hybrid systems for space exploration. Electrodes based on single-wall carbon nanotubes (SWCNTs) offer exceptional power and energy performance due to the high surface area, high conductivity, and the ability to functionalize the SWCNTs to optimize capacitor properties. This paper will report on the preparation of electrochemical capacitors incorporating SWCNT electrodes and their performance compared with existing commercial technology. Preliminary results indicate that substantial increases in power and energy density are possible. The effects of nanotube growth and processing methods on electrochemical capacitor performance is also presented. The compatibility of different SWCNTs and electrolytes was studied by varying the type of electrolyte ions that accumulate on the high-surface-area electrodes.

Broadband changes in the cortical surface potential track activation of functionally diverse neuronal populations

PubMed Central

Miller, Kai J; Honey, Christopher J; Hermes, Dora; Rao, Rajesh PN; denNijs, Marcel; Ojemann, Jeffrey G

2013-01-01

We illustrate a general principal of electrical potential measurements from the surface of the cerebral cortex, by revisiting and reanalyzing experimental work from the visual, language and motor systems. A naïve decomposition technique of electrocorticographic power spectral measurements reveals that broadband spectral changes reliably track task engagement. These broadband changes are shown to be a generic correlate of local cortical function across a variety of brain areas and behavioral tasks. Furthermore, they fit a power-law form that is consistent with simple models of the dendritic integration of asynchronous local population firing. Because broadband spectral changes covary with diverse perceptual and behavioral states on the timescale of 20–50ms, they provide a powerful and widely applicable experimental tool. PMID:24018305

Carbon Redox-Polymer-Gel Hybrid Supercapacitors

PubMed Central

Vlad, A.; Singh, N.; Melinte, S.; Gohy, J.-F.; Ajayan, P.M.

2016-01-01

Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances. PMID:26917470

A comparative reliability analysis of free-piston Stirling machines

NASA Astrophysics Data System (ADS)

Schreiber, Jeffrey G.

2001-02-01

A free-piston Stirling power convertor is being developed for use in an advanced radioisotope power system to provide electric power for NASA deep space missions. These missions are typically long lived, lasting for up to 14 years. The Department of Energy (DOE) is responsible for providing the radioisotope power system for the NASA missions, and has managed the development of the free-piston power convertor for this application. The NASA Glenn Research Center has been involved in the development of Stirling power conversion technology for over 25 years and is currently providing support to DOE. Due to the nature of the potential missions, long life and high reliability are important features for the power system. Substantial resources have been spent on the development of long life Stirling cryocoolers for space applications. As a very general statement, free-piston Stirling power convertors have many features in common with free-piston Stirling cryocoolers, however there are also significant differences. For example, designs exist for both power convertors and cryocoolers that use the flexure bearing support system to provide noncontacting operation of the close-clearance moving parts. This technology and the operating experience derived from one application may be readily applied to the other application. This similarity does not pertain in the case of outgassing and contamination. In the cryocooler, the contaminants normally condense in the critical heat exchangers and foul the performance. In the Stirling power convertor just the opposite is true as contaminants condense on non-critical surfaces. A methodology was recently published that provides a relative comparison of reliability, and is applicable to systems. The methodology has been applied to compare the reliability of a Stirling cryocooler relative to that of a free-piston Stirling power convertor. The reliability analysis indicates that the power convertor should be able to have superior reliability compared to the cryocooler. .

Pitting and Bending Fatigue Evaluations of a New Case-Carburized Gear Steel

NASA Technical Reports Server (NTRS)

Krantz, Timothy; Tufts, Brian

2007-01-01

The power density of a gearbox is an important consideration for many applications and is especially important for gearboxes used on aircraft. One approach to improving power density of gearing is to improve the steel properties by design of the alloy. The alloy tested in this work was designed to be case-carburized with surface hardness of Rockwell C66 after hardening. Test gear performance was evaluated using surface fatigue tests and single-tooth bending fatigue tests. The performance of gears made from the new alloy was compared to the performance of gears made from two alloys currently used for aviation gearing. The new alloy exhibited significantly better performance in surface fatigue testing, demonstrating the value of the improved properties in the case layer. However, the alloy exhibited lesser performance in single-tooth bending fatigue testing. The fracture toughness of the tested gears was insufficient for use in aircraft applications as judged by the behavior exhibited during the single tooth bending tests. This study quantified the performance of the new alloy and has provided guidance for the design and development of next generation gear steels.

Versatile microbial surface-display for environmental remediation and biofuels production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Cindy H.; Mulchandani, Ashok; Chen, wilfred

2008-02-14

Surface display is a powerful technique that utilizes natural microbial functional components to express proteins or peptides on the cell exterior. Since the reporting of the first surface-display system in the mid-1980s, a variety of new systems have been reported for yeast, Gram-positive and Gram-negative bacteria. Non-conventional display methods are emerging, eliminating the generation of genetically modified microorganisms. Cells with surface display are used as biocatalysts, biosorbents and biostimulants. Microbial cell-surface display has proven to be extremely important for numerous applications ranging from combinatorial library screening and protein engineering to bioremediation and biofuels production.

pMUT+ASIC integrated platform for wide range ultrasonic imaging

NASA Astrophysics Data System (ADS)

Tillak, J.; Saeed, N.; Khazaaleh, S.; Viegas, J.; Yoo, J.

2017-03-01

We propose an integrated platform of Aluminum Nitrate (AlN) based Piezoelectric Micromachined Ultrasonic Transducer (pMUT) phased array with Application Specific Integrated Circuit (ASIC) for medical imaging and industrial diagnosis. The ASIC provides wide driving range for frequencies between 100 kHz and 5 MHz and channelscalable, programmable application adaptive transmitting beamformer. The system supports operation in various media, including gasses, liquids and biological tissue. The scan resolution for 5 MHz operation is 68 μm in air. The beamformer covers a test volume from -30° to +30° with a step of 3° and scan depth of 10 cm. The ASIC system features low noise receiver electronics, power saving transmission circuitry, and high-voltage drive of large capacitance transducer (up to 500 pF). Integrated pMUT phased array consists of 4 channels of single-membrane ultrasonic transducer of 400 nm deflection and 20 pF feed-thru capacitance, which produce 15 Pa pressure at 500 μm distance from the surface of the transducers. The active area of the ASIC is (700×1490) μm2, which includes channel scalable TX, 8-channale low noise RX, digital back end with autonomous beamformer and power management unit. The system is battery powered with 3.3V-5V standard supply, representing a truly portable solution for ultrasonic applications. Given the CMOS-compatible fabrication process for the AlN pMUTs, dense, miniaturized arrays are possible. Furthermore the smooth surface of dielectric AlN renders optical quality MEMS surfaces for integration in miniaturized photonic + ultrasound microsystems.

Performance and durability of high emittance heat receiver surfaces for solar dynamic power systems

NASA Technical Reports Server (NTRS)

Degroh, Kim K.; Roig, David M.; Burke, Christopher A.; Shah, Dilipkumar R.

1994-01-01

Haynes 188, a cobalt-based superalloy, will be used to make thermal energy storage (TES) containment canisters for a 2 kW solar dynamic ground test demonstrator (SD GTD). Haynes 188 containment canisters with a high thermal emittance (epsilon) are desired for radiating heat away from local hot spots, improving the heating distribution, which will in turn improve canister service life. In addition to needing a high emittance, the surface needs to be durable in an elevated temperature, high vacuum environment for an extended time period. Thirty-five Haynes 188 samples were exposed to 14 different types of surface modification techniques for emittance and vacuum heat treatment (VHT) durability enhancement evaluation. Optical properties were obtained for the modified surfaces. Emittance enhanced samples were exposed to VHT for up to 2692 hours at 827 C and less than or equal to 10(exp -6) torr with integral thermal cycling. Optical properties were taken intermittently during exposure, and after final VHT exposure. The various surface modification treatments increased the emittance of pristine Haynes 188 from 0.11 up to 0.86. Seven different surface modification techniques were found to provide surfaces which met the SD GTD receiver VHT durability requirement. Of the 7 surface treatments, 2 were found to display excellent VHT durability: an alumina based (AB) coating and a zirconia based coating. The alumina based coating was chosen for the epsilon enhancement surface modification technique for the SD GTD receiver. Details of the performance and vacuum heat treatment durability of this coating and other Haynes 188 emittance surface modification techniques are discussed. Technology from this program will lead to successful demonstration of solar dynamic power for space applications, and has potential for application in other systems requiring high emittance surfaces.

Potential Applications for Radioisotope Power Systems in Support of Human Exploration Missions

NASA Technical Reports Server (NTRS)

Cataldo, Robert L.; Colozza, Anthony J.; Schmitz, Paul C.

2013-01-01

Radioisotope power systems (RPS) for space applications have powered over 27 U.S. space systems, starting with Transit 4A and 4B in 1961, and more recently with the successful landing of the Mars Science Laboratory rover Curiosity in August 2012. RPS enable missions with destinations far from the Sun with faint solar flux, on planetary surfaces with dense or dusty atmospheres, and at places with long eclipse periods where solar array sizes and energy storage mass become impractical. RPS could also provide an enabling capability in support of human exploration activities. It is envisioned that with the higher power needs of most human mission concepts, a high efficiency thermal-to-electric technology would be required such as the Advanced Stirling Radioisotope generator (ASRG). The ASRG should be capable of a four-fold improvement in efficiency over traditional thermoelectric RPS. While it may be impractical to use RPS as a main power source, many other applications could be considered, such as crewed pressurized rovers, in-situ resource production of propellants, back-up habitat power, drilling, any mobile or remote activity from the main base habitat, etc. This paper will identify potential applications and provide concepts that could be a practical extension of the current ASRG design in providing for robust and flexible use of RPS on human exploration missions.

Thermal Characteristics of ThermoBrachytherapy Surface Applicators (TBSA) for Treating Chestwall Recurrence

PubMed Central

Arunachalam, K.; Maccarini, P. F.; Craciunescu, O. I.; Schlorff, J. L.; Stauffer, P. R.

2010-01-01

Purpose To study temperature and thermal dose distributions of ThermoBrachytherapy Surface Applicators (TBSA) developed for concurrent or sequential high dose rate (HDR) brachytherapy and microwave hyperthermia treatment of chest wall recurrence and other superficial disease. Methods A steady state thermodynamics model coupled with the fluid dynamics of water bolus and electromagnetic radiation of hyperthermia applicator is used to characterize the temperature distributions achievable with TBSA applicators in an elliptical phantom model of the human torso. Power deposited by 915 MHz conformal microwave array (CMA) applicators is used to assess the specific absorption rate (SAR) distributions of rectangular (500 cm2) and L-shaped (875 cm2) TBSA. The SAR distribution in tissue and fluid flow distribution inside the Dual-Input Dual-Output (DIDO) water bolus are coupled to solve the steady state temperature and thermal dose distributions of rectangular TBSA (R-TBSA) for superficial tumor targets extending 10–15 mm beneath the skin surface. Thermal simulations are carried out for a range of bolus inlet temperature (Tb=38–43°C), water flow rate (Qb=2–4 L/min) and tumor blood perfusion (ωb=2–5 kg/m3/s) to characterize their influence on thermal dosimetry. Results Steady state SAR patterns of R- and L-TBSA demonstrate the ability to produce conformal and localized power deposition inside tumor target sparing surrounding normal tissues and nearby critical organs. Acceptably low variation in tissue surface cooling and surface temperature homogeneity was observed for the new DIDO bolus at 2 L/min water flow rate. Temperature depth profiles and thermal dose volume histograms indicate bolus inlet temperature (Tb) to be the most influential factor on thermal dosimetry. A 42 °C water bolus was observed to be the optimal choice for superficial tumors extending 10–15 mm from the surface even under significant blood perfusion. Lower bolus temperature may be chosen to reduce thermal enhancement ratio (TER) in the most sensitive skin where maximum radiation dose is delivered and to extend thermal enhancement of radiation dose deeper. Conclusion This computational study indicates that well-localized elevation of tumor target temperature to 40–44 °C can be accomplished by large surface-conforming TBSA applicators using appropriate selection of coupling bolus temperature. PMID:20224154

Photo-induced-heat localization on nanostructured metallic glasses

NASA Astrophysics Data System (ADS)

Uzun, Ceren; Kahler, Niloofar; Grave de Peralta, Luis; Kumar, Golden; Bernussi, Ayrton A.

2017-09-01

Materials with large photo-thermal energy conversion efficiency are essential for renewable energy applications. Photo-excitation is an effective approach to generate controlled and localized heat at relatively low excitation optical powers. However, lateral heat diffusion to the surrounding illuminated areas accompanied by low photo-thermal energy conversion efficiency remains a challenge for metallic surfaces. Surface nanoengineering has proven to be a successful approach to further absorption and heat generation. Here, we show that pronounced spatial heat localization and high temperatures can be achieved with arrays of amorphous metallic glass nanorods under infrared optical illumination. Thermography measurements revealed marked temperature contrast between illuminated and non-illuminated areas even under low optical power excitation conditions. This attribute allowed for generating legible photo-induced thermal patterns on textured metallic glass surfaces.

Conceptual design of a self-deployable, high performance parabolic concentrator for advanced solar-dynamic power systems

NASA Astrophysics Data System (ADS)

Dehne, Hans J.

1991-05-01

NASA has initiated technology development programs to develop advanced solar dynamic power systems and components for space applications beyond 2000. Conceptual design work that was performed is described. The main efforts were the: (1) conceptual design of self-deploying, high-performance parabolic concentrator; and (2) materials selection for a lightweight, shape-stable concentrator. The deployment concept utilizes rigid gore-shaped reflective panels. The assembled concentrator takes an annular shape with a void in the center. This deployable concentrator concept is applicable to a range of solar dynamic power systems of 25 kW sub e to in excess of 75 kW sub e. The concept allows for a family of power system sizes all using the same packaging and deployment technique. The primary structural material selected for the concentrator is a polyethyl ethylketone/carbon fiber composite also referred to as APC-2 or Vitrex. This composite has a nearly neutral coefficient of thermal expansion which leads to shape stable characteristics under thermal gradient conditions. Substantial efforts were undertaken to produce a highly specular surface on the composite. The overall coefficient of thermal expansion of the composite laminate is near zero, but thermally induced stresses due to micro-movement of the fibers and matrix in relation to each other cause the surface to become nonspecular.

Sol-gel derived electrode materials for supercapacitor applications

NASA Astrophysics Data System (ADS)

Lin, Chuan

1998-12-01

Electrochemical capacitors have been receiving increasing interest in recent years for use in energy storage systems because of their high energy and power density and long cycle lifes. Possible applications of electrochemical capacitors include high power pulsed lasers, hybrid power system for electric vehicles, etc. In this dissertation, the preparation of electrode materials for use as electrochemical capacitors has been studied using the sol-gel process. The high surface area electrode materials explored in this work include a synthetic carbon xerogel for use in a double-layer capacitor, a cobalt oxide xerogel for use in a pseudocapacitor, and a carbon-ruthenium xerogel composite, which utilizes both double-layer and faradaic capacitances. The preparation conditions of these materials were investigated in detail to maximize the surface area and optimize the pore size so that more energy could be stored while minimizing mass transfer limitations. The microstructures of the materials were also correlated with their performance as electrochemical capacitors to improve their energy and power densities. Finally, an idealistic mathematical model, including both double-layer and faradaic processes, was developed and solved numerically. This model can be used to perform the parametric studies of an electrochemical capacitor so as to gain a better understanding of how the capacitor works and also how to improve cell operations and electrode materials design.

Conceptual design of a self-deployable, high performance parabolic concentrator for advanced solar-dynamic power systems

NASA Technical Reports Server (NTRS)

Dehne, Hans J.

1991-01-01

NASA has initiated technology development programs to develop advanced solar dynamic power systems and components for space applications beyond 2000. Conceptual design work that was performed is described. The main efforts were the: (1) conceptual design of self-deploying, high-performance parabolic concentrator; and (2) materials selection for a lightweight, shape-stable concentrator. The deployment concept utilizes rigid gore-shaped reflective panels. The assembled concentrator takes an annular shape with a void in the center. This deployable concentrator concept is applicable to a range of solar dynamic power systems of 25 kW sub e to in excess of 75 kW sub e. The concept allows for a family of power system sizes all using the same packaging and deployment technique. The primary structural material selected for the concentrator is a polyethyl ethylketone/carbon fiber composite also referred to as APC-2 or Vitrex. This composite has a nearly neutral coefficient of thermal expansion which leads to shape stable characteristics under thermal gradient conditions. Substantial efforts were undertaken to produce a highly specular surface on the composite. The overall coefficient of thermal expansion of the composite laminate is near zero, but thermally induced stresses due to micro-movement of the fibers and matrix in relation to each other cause the surface to become nonspecular.

The Application of Surface Potential Test on Hand-making Insulation for Generator Stator End-winding

NASA Astrophysics Data System (ADS)

Lu, Zhu-mao; Liu, Qing; Wang, Tian-zheng; Bai, Lu; Li, Yan-peng

2017-05-01

This paper presents the advantage of surface potential test on hand-making insulation for generator stator end-winding insulation detection, compared with DC or AC withstand voltage test, also details the test principle, connection method and test notes. And through the case, surface potential test on hand-making insulation proved effective for insulation quality detection after generator stator end-winding maintenance, and the experimental data is useful and reliable for the electrical equipment operation and maintenance in the power plant.

Spacecraft-plasma interaction codes: NASCAP/GEO, NASCAP/LEO, POLAR, DynaPAC, and EPSAT

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Jongeward, G. A.; Cooke, D. L.

1992-01-01

Development of a computer code to simulate interactions between the surfaces of a geometrically complex spacecraft and the space plasma environment involves: (1) defining the relevant physical phenomena and formulating them in appropriate levels of approximation; (2) defining a representation for the 3-D space external to the spacecraft and a means for defining the spacecraft surface geometry and embedding it in the surrounding space; (3) packaging the code so that it is easy and practical to use, interpret, and present the results; and (4) validating the code by continual comparison with theoretical models, ground test data, and spaceflight experiments. The physical content, geometrical capabilities, and application of five S-CUBED developed spacecraft plasma interaction codes are discussed. The NASA Charging Analyzer Program/geosynchronous earth orbit (NASCAP/GEO) is used to illustrate the role of electrostatic barrier formation in daylight spacecraft charging. NASCAP/low Earth orbit (LEO) applications to the CHARGE-2 and Space Power Experiment Aboard Rockets (SPEAR)-1 rocket payloads are shown. DynaPAC application to the SPEAR-2 rocket payloads is described. Environment Power System Analysis Tool (EPSAT) is illustrated by application to Tethered Satellite System 1 (TSS-1), SPEAR-3, and Sundance. A detailed description and application of the Potentials of Large Objects in the Auroral Region (POLAR) Code are presented.

Preliminary Evaluation of Convective Heat Transfer in a Water Shield for a Surface Power Reactor

NASA Technical Reports Server (NTRS)

Pearson J. Boise; Reid, Robert S.

2007-01-01

As part of the Vision for Space Exploration, the end of the next decade will bring man back to the surface of the moon. A crucial issue for the establishment of human presence on the moon will be the availability of compact power sources. This presence could require greater than 10's of kWt's in follow on years. Nuclear reactors are well suited to meet the needs for power generation on the lunar or Martian surface. Radiation shielding is a key component of any surface power reactor system. Several competing concepts exist for lightweight, safe, robust shielding systems such as a water shield, lithium hydride (LiH), and boron carbide. Water offers several potential advantages, including reduced cost, reduced technical risk, and reduced mass. Water has not typically been considered for space reactor applications because of the need for gravity to fix the location of any vapor that could form radiation streaming paths. The water shield concept relies on the predictions of passive circulation of the shield water by natural convection to adequately cool the shield. This prediction needs to be experimentally evaluated, especially for shields with complex geometries. NASA Marshall Space Flight Center has developed the experience and facilities necessary to do this evaluation in its Early Flight Fission - Test Facility (EFF-TF).

Summary and recommendations on nuclear electric propulsion technology for the space exploration initiative

NASA Technical Reports Server (NTRS)

Doherty, Michael P.; Holcomb, Robert S.

1993-01-01

A project in Nuclear Electric Propulsion (NEP) technology is being established to develop the NEP technologies needed for advanced propulsion systems. A paced approach has been suggested which calls for progressive development of NEP component and subsystem level technologies. This approach will lead to major facility testing to achieve TRL-5 for megawatt NEP for SEI mission applications. This approach is designed to validate NEP power and propulsion technologies from kilowatt class to megawatt class ratings. Such a paced approach would have the benefit of achieving the development, testing, and flight of NEP systems in an evolutionary manner. This approach may also have the additional benefit of synergistic application with SEI extraterrestrial surface nuclear power applications.

Coupling and power transfer efficiency enhancement of modular and array of planar coils using in-plane ring-shaped inner ferrites for inductive heating applications

NASA Astrophysics Data System (ADS)

Kilic, V. T.; Unal, E.; Demir, H. V.

2017-07-01

We propose and demonstrate a highly effective method of enhancing coupling and power transfer efficiency in inductive heating systems composed of planar coils. The proposed method is based on locating ring-shaped ferrites in the inner side of the coils in the same plane. Measurement results of simple inductive heating systems constructed with either a single or a pair of conventional circular coils show that, with the in-plane inner ferrites, the total dissipated power of the system is increased by over 65%. Also, with three-dimensional full electromagnetic solutions, it is found that power transfer efficiency of the system is increased up to 92% with the inner ferrite placement. The proposed method is promising to be used for efficiency enhancement in inductive heating applications, especially in all-surface induction hobs.

The Applications of NASA Mission Technologies to the Greening of Human Impact

NASA Technical Reports Server (NTRS)

Sims, Michael H.

2009-01-01

I will give an overview talk about flight software systems, robotics technologies and modeling for energy minimization as applied to vehicles and buildings infrastructures. A dominant issue in both design and operations of robotic spacecraft is the minimization of energy use. In the design and building of spacecraft increased power is acquired only at the cost of additional mass and volumes and ultimately cost. Consequently, interplanetary spacecrafts are designed to have the minimum essential power and those designs often incorporate careful timing of all power use. Operationally, the availability of power is the most influential constraint for the use of planetary surface robots, such as the Mars Exploration Rovers. The amount of driving done, the amount of science accomplished and indeed the survivability of the spacecraft itself is determined by the power available for use. For the Mars Exploration Rovers there are four tools which are used: (1) models of the rover and it s thermal and power use (2) predictive environmental models of power input and thermal environment (3) fine grained manipulation of power use (4) optimization modeling and planning tools. In this talk I will discuss possible applications of this methodology to minimizing power use on Earth, especially in buildings.

High-power direct-diode laser successes

NASA Astrophysics Data System (ADS)

Haake, John M.; Zediker, Mark S.

2004-06-01

Direct diode laser will become much more prevalent in the solar system of manufacturing due to their high efficiency, small portable size, unique beam profiles, and low ownership costs. There has been many novel applications described for high power direct diode laser [HPDDL] systems but few have been implemented in extreme production environments due to diode and diode system reliability. We discuss several novel applications in which the HPDDL have been implemented and proven reliable and cost-effective in production environments. These applications are laser hardening/surface modification, laser wire feed welding and laser paint stripping. Each of these applications uniquely tests the direct diode laser systems capabilities and confirms their reliability in production environments. A comparison of the advantages direct diode laser versus traditional industrial lasers such as CO2 and Nd:YAG and non-laser technologies such a RF induction, and MIG welders for each of these production applications is presented.

Characterization and Application of a Planar Radio - Inductively-Coupled Plasma Source for the Production of Barrier Coatings.

NASA Astrophysics Data System (ADS)

Mahoney, Leonard Joseph

A planar radio-frequency (rf) inductively-coupled plasma (ICP) source is used to produce fluorocarbon discharges (CF_4/Ar) to fluorinate the surface of high-density polyethylene (HDPE). Using this system, concurrent studies of discharge characteristics, permeation properties of treated polymers and polymer surface characteristics are conducted to advance the use of plasma-fluorinated polymer surfaces as a barrier layer for automotive applications. Langmuir probes are used to determine spatial distribution of charged-particle and space-potential characteristics in Ar and CF_4/Ar discharges and to show the influence of the spatial distribution of the heating regions and the reactor boundaries on the discharge uniformity. Langmuir probes are also used to identify rf anisotropic drift motion of electrons in the heating regions of the source and transient high-energy electron features in pulsed discharges. These latter features allow pulsed ICP sources to be operated at low time-averaged powers that are necessary to treat thermally sensitive polymers. Fourier Transform Infrared (FITR) spectroscopy is used to measure the dissociation of fluorocarbon gases and to explore differences between pulsed- and continuous -power operation. Dissociation levels of CF_4 (50-85%) using pulsed-power operation are as high as that for continuous operation, even though the net time -averaged power is far less with pulsed operation. The result suggests that pulsed fluorocarbon discharges possess high concentrations of chemically-active species needed for rapid surface fluorination. A gravimetric permeation cup method is used to measure the permeation rate of test fuels through HDPE membranes, and electron spectroscopy for chemical analysis (ESCA) studies are performed to determine the stoichiometry and thickness of the barrier layer. From these studies we find that a 50-70 A thick, polar, fluoro-hydrocarbon over layer reduces the permeation of isooctane/toluene/methanol mixtures by a factor of 4. To increase the permeation resistance for automotive applications, this result points towards the deposition of a 1000 A thick fluoro-hydrocarbon barrier coating with stoichiometry and bond structures similar to the CF_4/Ar treated HDPE.

A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

NASA Astrophysics Data System (ADS)

Barsbay, Murat; Güven, Olgun

2009-12-01

Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly γ radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of γ radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of γ radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

Metrics for Evaluating the Accuracy of Solar Power Forecasting: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J.; Hodge, B. M.; Florita, A.

2013-10-01

Forecasting solar energy generation is a challenging task due to the variety of solar power systems and weather regimes encountered. Forecast inaccuracies can result in substantial economic losses and power system reliability issues. This paper presents a suite of generally applicable and value-based metrics for solar forecasting for a comprehensive set of scenarios (i.e., different time horizons, geographic locations, applications, etc.). In addition, a comprehensive framework is developed to analyze the sensitivity of the proposed metrics to three types of solar forecasting improvements using a design of experiments methodology, in conjunction with response surface and sensitivity analysis methods. The resultsmore » show that the developed metrics can efficiently evaluate the quality of solar forecasts, and assess the economic and reliability impact of improved solar forecasting.« less

Overview of Energy Storage Technologies for Space Applications

NASA Technical Reports Server (NTRS)

Surampudi, Subbarao

2006-01-01

This presentations gives an overview of the energy storage technologies that are being used in space applications. Energy storage systems have been used in 99% of the robotic and human space missions launched since 1960. Energy storage is used in space missions to provide primary electrical power to launch vehicles, crew exploration vehicles, planetary probes, and astronaut equipment; store electrical energy in solar powered orbital and surface missions and provide electrical energy during eclipse periods; and, to meet peak power demands in nuclear powered rovers, landers, and planetary orbiters. The power source service life (discharge hours) dictates the choice of energy storage technology (capacitors, primary batteries, rechargeable batteries, fuel cells, regenerative fuel cells, flywheels). NASA is planning a number of robotic and human space exploration missions for the exploration of space. These missions will require energy storage devices with mass and volume efficiency, long life capability, an the ability to operate safely in extreme environments. Advanced energy storage technologies continue to be developed to meet future space mission needs.

Laser prospects for SPS and restoration of the ozone layer

NASA Technical Reports Server (NTRS)

Kruzhilin, Yuri

1992-01-01

Large-scale applications of high-power lasers are considered (special experiments are described to confirm the feasibility of these applications) to achieve also large-scale environmental advantages. The possibility of producing electric energy by Laser-Solar Power Satellites in the near future is discussed. A full-scale experimental L-SPS satellite is suggested as a module of a global space energy network. Electric power of about 10 MW at the surface of the Earth is achievable as a result of energy conversion of laser radiation. L-SPS is based on the greatest advantages of present optics and laser techniques. Specialized-scale experiments are carried out and described. L-SPS project could provide real electricity for consumers not later than by highly developed fusion techniques, and the environmental aftereffects are quite favorable. A new method of power supply for satellites is suggested, based on the connection of an on-board electric circuit directly with the ground-based power grid by means of laser beams.

Surface coil proton MR imaging at 2 T.

PubMed

Röschmann, P; Tischler, R

1986-10-01

We describe the design and application of surface coils for magnetic resonance (MR) imaging at high resonance frequencies (85 MHz). Circular, rectangular-frame, and reflector-type surface coils were used in the transmit-and-receive mode. With these coils, the required radio frequency power is reduced by factors of two up to 100 with respect to head and body coils. With the small, circular coils, high-resolution images of a small region of interest can be obtained that are free of foldback and motion artifacts originating outside the field of interest. With the rectangular-frame and reflector coils, large fields of view are also accessible. As examples of applications, single- and multiple-section images of the eye, knee, head and shoulder, and spinal cord are provided.

MEASUREMENTS OF THE CONFINEMENT LEAKTIGHTNESS AT THE KOLA NUCLEAR POWER STATION (UNIT 2) IN RUSSIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

GREENE,G.A.; GUPPY,J.G.

1998-08-01

This is the final report on the INSP project entitled, ``Kola Confinement Leaktightness'' conducted by BNL under the authorization of Project Work Plan WBS 1.2.2.1. This project was initiated in February 1993 to assist the Russians to reduce risks associated with the continued operation of older Soviet-designed nuclear power plants, specifically the Kola VVER-440/230 Units 1 and 2, through upgrades in the confinement performance to reduce the uncontrolled leakage rate. The major technical objective of this-project was to improve the leaktightness of the Kola NPP VVER confinement boundaries, through the application of a variety of sealants to penetrations, doors andmore » hatches, seams and surfaces, to the extent that current technology permitted. A related objective was the transfer, through training of Russian staff, of the materials application procedures to the staff of the Kola NPP. This project was part of an overall approach to minimizing uncontrolled releases from the Kola NPP VVER440/230s in the event of a serious accident, and to thereby significantly mitigate the consequences of such an accident. The US provided materials, application technology, and applications equipment for application of sealant materials, surface coatings, potting materials and gaskets, to improve the confinement leaktightness of the Kola VVER-440/23Os. The US provided for training of Russian personnel in the applications technology.« less

Dynamics of Wetting of Ultra Hydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Mohammad Karim, Alireza; Kim, Jeong-Hyun; Rothstein, Jonathan; Kavehpour, Pirouz; Mechanical and Industrial Engineering, University of Massachusetts, Amherst Collaboration

2013-11-01

Controlling the surface wettability of hydrophobic and super hydrophobic surfaces has extensive industrial applications ranging from coating, painting and printing technology and waterproof clothing to efficiency increase in power and water plants. This requires enhancing the knowledge about the dynamics of wetting on these hydrophobic surfaces. We have done experimental investigation on the dynamics of wetting on hydrophobic surfaces by looking deeply in to the dependency of the dynamic contact angles both advancing and receding on the velocity of the three-phase boundary (Solid/Liquid/Gas interface) using the Wilhelmy plate method with different ultra-hydrophobic surfaces. Several fluids with different surface tension and viscosity are used to study the effect of physical properties of liquids on the governing laws.

QCM-D study of nanoparticle interactions.

PubMed

Chen, Qian; Xu, Shengming; Liu, Qingxia; Masliyah, Jacob; Xu, Zhenghe

2016-07-01

Quartz crystal microbalance with dissipation monitoring (QCM-D) has been proven to be a powerful research tool to investigate in situ interactions between nanoparticles and different functionalized surfaces in liquids. QCM-D can also be used to quantitatively determine adsorption kinetics of polymers, DNA and proteins from solutions on various substrate surfaces while providing insights into conformations of adsorbed molecules. This review aims to provide a comprehensive overview on various important applications of QCM-D, focusing on deposition of nanoparticles and attachment-detachment of nanoparticles on model membranes in complex fluid systems. We will first describe the working principle of QCM-D and DLVO theory pertinent to understanding nanoparticle deposition phenomena. The interactions between different nanoparticles and functionalized surfaces for different application areas are then critically reviewed. Finally, the potential applications of QCM-D in other important fields are proposed and knowledge gaps are identified. Copyright © 2015 Elsevier B.V. All rights reserved.

SEI power source alternatives for rovers and other multi-kWe distributed surface applications

NASA Technical Reports Server (NTRS)

Bents, David J.; Kohout, L. L.; Mckissock, Barbara I.; Rodriguez, C. D.; Withrow, C. A.; Colozza, A.; Hanlon, James C.; Schmitz, Paul C.

1991-01-01

To support the Space Exploration Initiative (SEI), a study was performed to investigate power system alternatives for the rover vehicles and servicers that were subsequently generated for each of these rovers and servicers, candidate power sources incorporating various power generation and energy storage technologies were identified. The technologies were those believed most appropriate to the SEI missions, and included solar, electrochemical, and isotope systems. The candidates were characterized with respect to system mass, deployed area, and volume. For each of the missions a preliminary selection was made. Results of this study depict the available power sources in light of mission requirements as they are currently defined.

Experimental Investigation on the Detection of Multiple Surface Cracks Using Vibrothermography with a Low-Power Piezoceramic Actuator.

PubMed

Xu, Changhang; Xie, Jing; Zhang, Wuyang; Kong, Qingzhao; Chen, Guoming; Song, Gangbing

2017-11-23

Vibrothermography often employs a high-power actuator to generate heat on a specimen to reveal damage, however, the high-power actuator brings inconvenience to the application and possibly introduces additional damage to the inspected objects. This study uses a low-power piezoceramic transducer as the actuator of vibrothermography and explores its ability to detect multiple surface cracks in a metal part. Experiments were conducted on a thin aluminum beam with three cracks in different orientations. Detailed analyses of both thermograms and temperature data are presented to validate the proposed vibrothermography method. To further investigate the performance of the proposed vibrothermography method, we experimentally studied the effects of several critical factors, including the amplitude of excitation signal, specimen constraints, relative position between the transducer and cracks (the transducer is mounted on the same or the opposite side with the cracks). The results demonstrate that all cracks can be detected conveniently and simultaneously by using the proposed low-power vibrothermography. We also found that the magnitude of excitation signal and the specimen constraints have a great influence on detection results. Combined with effective data processing methods, such as Fourier transformation employed in this study, the proposed method provides a promising potential to detect multiple cracks on a metal surface in a safe and effective manner.

Triboelectrification-Enabled Self-Powered Data Storage.

PubMed

Kuang, Shuang Yang; Zhu, Guang; Wang, Zhong Lin

2018-02-01

Data storage by any means usually requires an electric driving power for writing or reading. A novel approach for self-powered, triboelectrification-enabled data storage (TEDS) is presented. Data are incorporated into a set of metal-based surface patterns. As a probe slides across the patterned surface, triboelectrification between the scanning probe and the patterns produces alternatively varying voltage signal in quasi-square wave. The trough and crest of the quasi-square wave signal are coded as binary bits of "0" and "1," respectively, while the time span of the trough and the crest is associated with the number of bits. The storage of letters and sentences is demonstrated through either square-shaped or disc-shaped surface patterns. Based on experimental data and numerical calculation, the theoretically predicted maximum data storage density could reach as high as 38.2 Gbit in -2 . Demonstration of real-time data retrieval is realized with the assistance of software interface. For the TEDS reported in this work, the measured voltage signal is self-generated as a result of triboelectrification without the reliance on an external power source. This feature brings about not only low power consumption but also a much more simplified structure. Therefore, this work paves a new path to a unique approach of high-density data storage that may have widespread applications.

NASA's future space power needs and requirements

NASA Technical Reports Server (NTRS)

Schnyer, A. D.; Sovie, Ronald J.

1990-01-01

The National Space Policy of 1988 established the U.S.'s long-range civil space goals, and has served to guide NASA's recent planning for future space mission operations. One of the major goals was to extend the human presence beyond earth's boundaries and to advance the scientific knowledge of the solar system. A broad spectrum of potential civil space mission opportunities and interests are currently being investigated by NASA to meet the espoused goals. Participation in many of these missions requires power systems with capabilities far beyond what exists today. In other mission examples, advanced power systems technology could enhance mission performance significantly. Power system requirements and issues that need resolution to ensure eventual mission accomplishment are addressed, in conjunction with the ongoing NASA technology development efforts and the need for even greater innovative efforts to match the ambitious solar exploration mission goals. Particular attention is given to potential lunar surface operations and technology goals, based on investigations to date. It is suggested that the nuclear reactor power systems can best meet long-life requirements as well as dramatically reduce the earth-surface-to-lunar-surface transportation costs due to the lunar day/night cycle impact on the solar system's energy storage mass requirements. The state of the art of candidate power systems and elements for the lunar application and the respective exploration technology goals for mission life requirements from 10 to 25 years are examined.

The RF-powered surface wave sensor oscillator--a successful alternative to passive wireless sensing.

PubMed

Avramov, Ivan D

2004-09-01

A novel, passive wireless surface acoustic wave (SAW) sensor providing a highly coherent measurand proportional frequency, frequency modulated (FM) with identification (ID) data and immune to interference with multiple-path signals is described. The sensor is appropriate for bandwidth-limited applications requiring high-frequency accuracy. It comprises a low-power oscillator, stabilized with the sensing SAW resonator and powered by the rectified radio frequency (RF) power of the interrogating signal received by an antenna on the sensor part. A few hundred microwatts of direct current (DC) power are enough to power the sensor oscillator and ID modulation circuit and achieve stable operation at 1.0 and 2.49 GHz. Reliable sensor interrogation was achieved over a distance of 0.45 m from a SAW-based interrogation unit providing 50 mW of continuous RF power at 915 MHz. The -30 to -35 dBm of returned sensor power was enough to receive the sensor signal over a long distance and through several walls with a simple superheterodyne FM receiver converting the sensor signal to a low measurand proportional intermediate frequency and retrieving the ID data through FM detection. Different sensor implementations, including continuous and pulsed power versions and the possibility of transmitting data from several measurands with a single sensor, are discussed.

Mars, the Moon, and the Ends of the Earth: Autonomy for Small Reactor Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Richard Thomas

2008-01-01

In recent years, the National Aeronautics and Space Administration (NASA) has been considering deep space missions that utilize a small-reactor power system (SRPS) to provide energy for propulsion and spacecraft power. Additionally, application of SRPS modules as a planetary power source is being investigated to enable a continuous human presence for nonpolar lunar sites and on Mars. A SRPS can supply high-sustained power for space and surface applications that is both reliable and mass efficient. The use of small nuclear reactors for deep space or planetary missions presents some unique challenges regarding the operations and control of the power system.more » Current-generation terrestrial nuclear reactors employ varying degrees of human control and decision-making for operations and benefit from periodic human interaction for maintenance. In contrast, the control system of a SRPS employed for deep space missions must be able to accommodate unattended operations due to communications delays and periods of planetary occlusion while adapting to evolving or degraded conditions with no opportunity for repair or refurbishment. While surface power systems for planetary outposts face less extreme delays and periods of isolation and may benefit from limited maintenance capabilities, considerations such as human safety, resource limitations and usage priorities, and economics favor minimizing direct, continuous human interaction with the SRPS for online, dedicated power system management. Thus, a SRPS control system for space or planetary missions must provide capabilities for operational autonomy. For terrestrial reactors, large-scale power plants remain the preferred near-term option for nuclear power generation. However, the desire to reduce reliance on carbon-emitting power sources in developing countries may lead to increased consideration of SRPS modules for local power generation in remote regions that are characterized by emerging, less established infrastructures. Additionally, many Generation IV (Gen IV) reactor concepts have goals for optimizing investment recovery and economic efficiency that promote significant reductions in plant operations and maintenance staff over current-generation nuclear power plants. To accomplish these Gen IV goals and also address the SRPS remote-siting challenges, higher levels of automation, fault tolerance, and advanced diagnostic capabilities are needed to provide nearly autonomous operations with anticipatory maintenance. Essentially, the SRPS control system for several anticipated terrestrial applications can benefit from the kind of operational autonomy that is necessary for deep space and planetary SRPS-enabled missions. Investigation of the state of the technology for autonomous control confirmed that control systems with varying levels of autonomy have been employed in robotic, transportation, spacecraft, and manufacturing applications. As an example, NASA has pursued autonomy for spacecraft and surface exploration vehicles (e.g., rovers) to reduce mission costs, increase efficiency for communications between ground control and the vehicle, and enable independent operation of the vehicle during times of communications blackout. However, autonomous control has not been implemented for an operating terrestrial nuclear power plant nor has there been any experience beyond automating simple control loops for space reactors. Current automated control technologies for nuclear power plants are reasonably mature, and fully automated control of normal SRPS operations is clearly feasible. However, the space-based and remote terrestrial applications of SRPS modules require autonomous capabilities that can accommodate nonoptimum operations when degradation, failure, and other off-normal events challenge the performance of the reactor while immediate human intervention is not possible. The independent action provided by autonomous control, which is distinct from the more limited self action of automated control, can satisfy these conditions. Key characteristics that distinguish autonomous control include: (1) intelligence to confirm system performance and detect degraded or failed conditions, (2) optimization to minimize stress on SRPS components and efficiently react to operational events without compromising system integrity, (3) robustness to accommodate uncertainties and changing conditions, and (4) flexibility and adaptability to accommodate failures through reconfiguration among available control system elements or adjustment of control system strategies, algorithms, or parameters.« less

Economics of electron beam and electrical discharge processing for post-combustion NO(x) control in internal combustion engines

NASA Astrophysics Data System (ADS)

Penetrante, B. M.

1993-08-01

The physics and chemistry of non-thermal plasma processing for post-combustion NO(x) control in internal combustion engines are discussed. A comparison of electron beam and electrical discharge processing is made regarding their power consumption, radical production, NO(x) removal mechanisms, and by-product formation. Pollution control applications present a good opportunity for transferring pulsed power techniques to the commercial sector. However, unless advances are made to drastically reduce the price and power consumption of electron beam sources and pulsed power systems, these plasma techniques will not become commercially competitive with conventional thermal or surface-catalytic methods.

A megawatt-level surface wave oscillator in Y-band with large oversized structure driven by annular relativistic electron beam.

PubMed

Wang, Jianguo; Wang, Guangqiang; Wang, Dongyang; Li, Shuang; Zeng, Peng

2018-05-03

High power vacuum electronic devices of millimeter wave to terahertz regime are attracting extensive interests due to their potential applications in science and technologies. In this paper, the design and experimental results of a powerful compact oversized surface wave oscillator (SWO) in Y-band are presented. The cylindrical slow wave structure (SWS) with rectangular corrugations and large diameter about 6.8 times the radiation wavelength is proposed to support the surface wave interacting with annular relativistic electron beam. By choosing appropriate beam parameters, the beam-wave interaction takes place near the π-point of TM 01 mode dispersion curve, giving high coupling impedance and temporal growth rate compared with higher TM 0n modes. The fundamental mode operation of the device is verified by the particle-in-cell (PIC) simulation results, which also indicate its capability of tens of megawatts power output in the Y-band. Finally, a compact experimental setup is completed to validate our design. Measurement results show that a terahertz pulse with frequency in the range of 0.319-0.349 THz, duration of about 2 ns and radiation power of about 2.1 MW has been generated.

Zero-power receiver

DOEpatents

Brocato, Robert W.

2016-10-04

An unpowered signal receiver and a method for signal reception detects and responds to very weak signals using pyroelectric devices as impedance transformers and/or demodulators. In some embodiments, surface acoustic wave devices (SAW) are also used. Illustrative embodiments include satellite and long distance terrestrial communications applications.

78 FR 929 - Georgia Power Company; Notice of Application Tendered for Filing With the Commission and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-07

...,850-acre reservoir (Bartletts Ferry Reservoir or Lake Harding) at a normal water surface elevation of... operated in a peaking mode, and is coordinated with the peaking operations at the U.S. Army Corps of...

High temperature co-axial winding transformers

NASA Technical Reports Server (NTRS)

Divan, Deepakraj M.; Novotny, Donald W.

1993-01-01

The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

Compact, Lightweight Dual- Frequency Microstrip Antenna Feed for Future Soil Moisture and Sea Surface Salinity Missions

NASA Technical Reports Server (NTRS)

Yueh, Simon H.; Wilson, William J.; Njoku, Eni; Hunter, Don; Dinardo, Steve; Kona, Keerti S.; Manteghi, Majid; Gies, Dennis; Rahmat-Samii, Yahya

2004-01-01

The development of a compact, lightweight, dual frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described. The design is based on the microstrip stacked-patch array (MSPA) to be used to feed a large lightweight deployable rotating mesh antenna for spaceborne L-band (approx. 1 GHz) passive and active sensing systems. The design features will also enable applications to airborne sensors operating on small aircrafts. This paper describes the design of stacked patch elements, 16-element array configuration and power-divider beam forming network The test results from the fabrication of stacked patches and power divider were also described.

Controllable superhydrophobic aluminum surfaces with tunable adhesion fabricated by femtosecond laser

NASA Astrophysics Data System (ADS)

Song, Yuxin; Wang, Cong; Dong, Xinran; Yin, Kai; Zhang, Fan; Xie, Zheng; Chu, Dongkai; Duan, Ji'an

2018-06-01

In this study, a facile and detailed strategy to fabricate superhydrophobic aluminum surfaces with controllable adhesion by femtosecond laser ablation is presented. The influences of key femtosecond laser processing parameters including the scanning speed, laser power and interval on the wetting properties of the laser-ablated surfaces are investigated. It is demonstrated that the adhesion between water and superhydrophobic surface can be effectively tuned from extremely low adhesion to high adhesion by adjusting laser processing parameters. At the same time, the mechanism is discussed for the changes of the wetting behaviors of the laser-ablated surfaces. These superhydrophobic surfaces with tunable adhesion have many potential applications, such as self-cleaning surface, oil-water separation, anti-icing surface and liquid transportation.

Recent advances in M13 bacteriophage-based optical sensing applications.

PubMed

Kim, Inhong; Moon, Jong-Sik; Oh, Jin-Woo

2016-01-01

Recently, M13 bacteriophage has started to be widely used as a functional nanomaterial for various electrical, chemical, or optical applications, such as battery components, photovoltaic cells, sensors, and optics. In addition, the use of M13 bacteriophage has expanded into novel research, such as exciton transporting. In these applications, the versatility of M13 phage is a result of its nontoxic, self-assembling, and specific binding properties. For these reasons, M13 phage is the most powerful candidate as a receptor for transducing chemical or optical phenomena of various analytes into electrical or optical signal. In this review, we will overview the recent progress in optical sensing applications of M13 phage. The structural and functional characters of M13 phage will be described and the recent results in optical sensing application using fluorescence, surface plasmon resonance, Förster resonance energy transfer, and surface enhanced Raman scattering will be outlined.

Recent advances in M13 bacteriophage-based optical sensing applications

NASA Astrophysics Data System (ADS)

Kim, Inhong; Moon, Jong-Sik; Oh, Jin-Woo

2016-10-01

Recently, M13 bacteriophage has started to be widely used as a functional nanomaterial for various electrical, chemical, or optical applications, such as battery components, photovoltaic cells, sensors, and optics. In addition, the use of M13 bacteriophage has expanded into novel research, such as exciton transporting. In these applications, the versatility of M13 phage is a result of its nontoxic, self-assembling, and specific binding properties. For these reasons, M13 phage is the most powerful candidate as a receptor for transducing chemical or optical phenomena of various analytes into electrical or optical signal. In this review, we will overview the recent progress in optical sensing applications of M13 phage. The structural and functional characters of M13 phage will be described and the recent results in optical sensing application using fluorescence, surface plasmon resonance, Förster resonance energy transfer, and surface enhanced Raman scattering will be outlined.

Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

NASA Astrophysics Data System (ADS)

Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

2007-01-01

The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

NASA Technical Reports Server (NTRS)

Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

2007-01-01

The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 10(exp 13) to 10(exp 15) n per square centimeters. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 10(exp 15) to 10(exp 16) n per square centimeters with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

Consumption of the electric power inside silent discharge reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yehia, Ashraf, E-mail: yehia30161@yahoo.com

An experimental study was made in this paper to investigate the relation between the places of the dielectric barriers, which cover the surfaces of the electrodes in the coaxial cylindrical reactors, and the rate of change of the electric power that is consumed in forming silent discharges. Therefore, silent discharges have been formed inside three coaxial cylindrical reactors. The dielectric barriers in these reactors were pasted on both the internal surface of the outer electrode in the first reactor and the external surface of the inner electrode in the second reactor as well as the surfaces of the two electrodesmore » in the third reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at normal temperature and pressure, in parallel with the application of a sinusoidal ac voltage between the electrodes of the reactor. The electric power consumed in forming the silent discharges inside the three reactors was measured as a function of the ac peak voltage. The validity of the experimental results was investigated by applying Manley's equation on the same discharge conditions. The results have shown that the rate of consumption of the electric power relative to the ac peak voltage per unit width of the discharge gap improves by a ratio of either 26.8% or 80% or 128% depending on the places of the dielectric barriers that cover the surfaces of the electrodes inside the three reactors.« less

Materials Challenges and Opportunities of Lithium-ion Batteries for Electrical Energy Storage

NASA Astrophysics Data System (ADS)

Manthiram, Arumugam

2011-03-01

Electrical energy storage has emerged as a topic of national and global importance with respect to establishing a cleaner environment and reducing the dependence on foreign oil. Batteries are the prime candidates for electrical energy storage. They are the most viable near-term option for vehicle applications and the efficient utilization of intermittent energy sources like solar and wind. Lithium-ion batteries are attractive for these applications as they offer much higher energy density than other rechargeable battery systems. However, the adoption of lithium-ion battery technology for vehicle and stationary storage applications is hampered by high cost, safety concerns, and limitations in energy, power, and cycle life, which are in turn linked to severe materials challenges. This presentation, after providing an overview of the current status, will focus on the physics and chemistry of new materials that can address these challenges. Specifically, it will focus on the design and development of (i) high-capacity, high-voltage layered oxide cathodes, (ii) high-voltage, high-power spinel oxide cathodes, (iii) high-capacity silicate cathodes, and (iv) nano-engineered, high-capacity alloy anodes. With high-voltage cathodes, a critical issue is the instability of the electrolyte in contact with the highly oxidized cathode surface and the formation of solid-electrolyte interfacial (SEI) layers that degrade the performance. Accordingly, surface modification of cathodes with nanostructured materials and self-surface segregation during the synthesis process to suppress SEI layer formation and enhance the energy, power, and cycle life will be emphasized. With the high-capacity alloy anodes, a critical issue is the huge volume change occurring during the charge-discharge process and the consequent poor cycle life. Dispersion of the active alloy nanoparticles in an inactive metal oxide-carbon matrix to mitigate this problem and realize long cycle life will be presented.

A Review of Radiolysis Concerns for Water Shielding in Fission Surface Power Applications

NASA Technical Reports Server (NTRS)

Schoenfeld, Michael P.

2008-01-01

This paper presents an overview of radiolysis concerns with regard to water shields for fission surface power. A review of the radiolysis process is presented and key parameters and trends are identified. From this understanding of the radiolytic decomposition of water, shield pressurization and corrosion are identified as the primary concerns. Existing experimental and modeling data addressing concerns are summarized. It was found that radiolysis of pure water in a closed volume results in minimal, if any net decomposition, and therefore reduces the potential for shield pressurization and corrosion. With the space program focus m emphasize more on permanent return to the Moon and eventually manned exploration of Mars, there has been a renewed look at fission power to meet the difficult technical & design challenges associated with this effort. This is due to the ability of fission power to provide a power rich environment that is insensitive to solar intensity and related aspects such as duration of night, dusty environments, and distance from the sun, etc. One critical aspect in the utilization of fission power for these applications of manned exploration is shielding. Although not typically considered for space applications, water shields have been identified as one potential option due to benefits in mass savings and reduced development cost and technical risk (Poston, 2006). However, the water shield option requires demonstration of its ability to meet key technical challenges including such things as adequate natural circulation for thermal management and capability for operational periods up to 8 years. Thermal management concerns have begun to be addressed and are not expected to be a problem (Pearson, 2007). One significant concern remaining is the ability to maintain the shield integrity through its operational lifetime. Shield integrity could be compromised through shield pressurization and corrosion resulting from the radiolytic decomposition of water.

A novel carbon electrode material for highly improved EDLC performance.

PubMed

Fang, Baizeng; Binder, Leo

2006-04-20

Porous materials, developed by grafting functional groups through chemical surface modification with a surfactant, represent an innovative concept in energy storage. This work reports, in detail, the first practical realization of a novel carbon electrode based on grafting of vinyltrimethoxysilane (vtmos) functional group for energy storage in electric double layer capacitor (EDLC). Surface modification with surfactant vtmos enhances the hydrophobisation of activated carbon and the affinity toward propylene carbonate (PC) solvent, which improves the wettability of activated carbon in the electrolyte solution based on PC solvent, resulting in not only a lower resistance to the transport of electrolyte ions within micropores of activated carbon but also more usable surface area for the formation of electric double layer, and accordingly, higher specific capacitance, energy density, and power capability available from the capacitor based on modified carbon. Especially, the effects from surface modification become superior at higher discharge rate, at which much better EDLC performance (i.e., much higher energy density and power capability) has been achieved by the modified carbon, suggesting that the modified carbon is a novel and very promising electrode material of EDLC for large current applications where both high energy density and power capability are required.

Optical design of transmitter lens for asymmetric distributed free space optical networks

NASA Astrophysics Data System (ADS)

Wojtanowski, Jacek; Traczyk, Maciej

2018-05-01

We present a method of transmitter lens design dedicated for light distribution shaping on a curved and asymmetric target. In this context, target is understood as a surface determined by hypothetical optical detectors locations. In the proposed method, ribbon-like surfaces of arbitrary shape are considered. The designed lens has the task to transform collimated and generally non-uniform input beam into desired irradiance distribution on such irregular targets. Desired irradiance is associated with space-dependant efficiency of power flow between the source and receivers distributed on the target surface. This unconventional nonimaging task is different from most illumination or beam shaping objectives, where constant or prescribed irradiance has to be produced on a flat target screen. The discussed optical challenge comes from the applications where single transmitter cooperates with multitude of receivers located in various positions in space and oriented in various directions. The proposed approach is not limited to optical networks, but can be applied in a variety of other applications where nonconventional irradiance distribution has to be engineered. The described method of lens design is based on geometrical optics, radiometry and ray mapping philosophy. Rays are processed as a vector field, each of them carrying a certain amount of power. Having the target surface shape and orientation of receivers distribution, the rays-surface crossings map is calculated. It corresponds to the output rays vector field, which is referred to the calculated input rays spatial distribution on the designed optical surface. The application of Snell's law in a vector form allows one to obtain surface local normal vector and calculate lens profile. In the paper, we also present the case study dealing with exemplary optical network. The designed freeform lens is implemented in commercially available optical design software and irradiance three-dimensional spatial distribution is examined, showing perfect agreement with expectations.

Superhydrophobic surfaces for applications in seawater.

PubMed

Ferrari, Michele; Benedetti, Alessandro

2015-08-01

Technological fields in which seawater is implied are numerorus, working in seawater (shipping, oil industry, marine aquaculture,..), and exploiting seawater in plants (cooling heat-exchange, desalination, power plants,..). All suffer from detrimental effects induced by biofouling mainly enhancing material failures and limiting energetic efficiencies. Among the remediation solutions, technologies coniugating economical, green and efficiency criteria should represent the direction. With the aim to meet these criteria, superhydrophobic (SH) technology attracted many researches for the protection of materials operating in contact with seawater. In this work, the literature focusing on such technology for the protection of surfaces in contact with seawater has been reviewed, mainly focusing on boat and ship hull protection. Despite the growing interest around SH technology in seawater for fouling control and friction drag reduction of hulls, to date literature shows that superhydrophobicity in seawater is still limited if compared with a time window compatible with technological needs (set on years). An evaluation of the causes of early superhydrophobicity loss under operative conditions clearly indicates that, to the best of present knowledge, a SH surface cannot preserve this feature by itself alone (especially in real seawater). Hence, we have considered to highlight the behaviour of SH surfaces in seawater in relation to early stages of biocolonization (conditioning film and pioneering bioslime formation). Considering the annual costs sustained for the biofouling impact control, advantages coming from SH surfaces, in terms of foul control and friction drag reduction, would allow economical savings allowing to cover both the appliance of longevity keeping strategies of the SH surfaces and investments in green technologies of SH coating life cycle (production, storing). In addition a brief outlook is provided on technological fields exploiting seawater in pipelines (power and desalination plants), where the SH surface finishing finds potentially interesting application for fouling and corrosion prevention applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of a scattered-light radiometric power meter.

PubMed

Caron, James N; DiComo, Gregory P; Ting, Antonio C; Fischer, Richard P

2011-04-01

The power measurement of high-power continuous-wave laser beams typically calls for the use of water-cooled thermopile power meters. Large thermopile meters have slow response times that can prove insufficient to conduct certain tests, such as determining the influence of atmospheric turbulence on transmitted beam power. To achieve faster response times, we calibrated a digital camera to measure the power level as the optical beam is projected onto a white surface. This scattered-light radiometric power meter saves the expense of purchasing a large area power meter and the required water cooling. In addition, the system can report the power distribution, changes in the position, and the spot size of the beam. This paper presents the theory of the scattered-light radiometric power meter and demonstrates its use during a field test at a 2.2 km optical range. © 2011 American Institute of Physics

Study on development system of increasing gearbox for high-performance wind-power generator

NASA Astrophysics Data System (ADS)

Xu, Hongbin; Yan, Kejun; Zhao, Junyu

2005-12-01

Based on the analysis of the development potentiality of wind-power generator and domestic manufacture of its key parts in China, an independent development system of the Increasing Gearbox for High-performance Wind-power Generator (IGHPWG) was introduced. The main elements of the system were studied, including the procedure design, design analysis system, manufacturing technology and detecting system, and the relative important technologies were analyzed such as mixed optimal joint transmission structure of the first planetary drive with two grade parallel axle drive based on equal strength, tooth root round cutting technology before milling hard tooth surface, high-precise tooth grinding technology, heat treatment optimal technology and complex surface technique, and rig test and detection technique of IGHPWG. The development conception was advanced the data share and quality assurance system through all the elements of the development system. The increasing Gearboxes for 600KW and 1MW Wind-power Generator have been successfully developed through the application of the development system.

Analytical study of STOL Aircraft in ground effect. Part 1: Nonplanar, nonlinear wing/jet lifting surface method

NASA Technical Reports Server (NTRS)

Shollenberger, C. A.; Smyth, D. N.

1978-01-01

A nonlinear, nonplanar three dimensional jet flap analysis, applicable to the ground effect problem, is presented. Lifting surface methodology is developed for a wing with arbitrary planform operating in an inviscid and incompressible fluid. The classical, infintely thin jet flap model is employed to simulate power induced effects. An iterative solution procedure is applied within the analysis to successively approximate the jet shape until a converged solution is obtained which closely satisfies jet and wing boundary conditions. Solution characteristics of the method are discussed and example results are presented for unpowered, basic powered and complex powered configurations. Comparisons between predictions of the present method and experimental measurements indicate that the improvement of the jet with the ground plane is important in the analyses of powered lift systems operating in ground proximity. Further development of the method is suggested in the areas of improved solution convergence, more realistic modeling of jet impingement and calculation efficiency enhancements.

Advanced Stirling Technology Development at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Wong, Wayne A.

2007-01-01

The NASA Glenn Research Center has been developing advanced energy-conversion technologies for use with both radioisotope power systems and fission surface power systems for many decades. Under NASA's Science Mission Directorate, Planetary Science Theme, Technology Program, Glenn is developing the next generation of advanced Stirling convertors (ASCs) for use in the Department of Energy/Lockheed Martin Advanced Stirling Radioisotope Generator (ASRG). The next-generation power-conversion technologies require high efficiency and high specific power (watts electric per kilogram) to meet future mission requirements to use less of the Department of Energy's plutonium-fueled general-purpose heat source modules and reduce system mass. Important goals include long-life (greater than 14-yr) reliability and scalability so that these systems can be considered for a variety of future applications and missions including outer-planet missions and continual operation on the surface of Mars. This paper provides an update of the history and status of the ASC being developed for Glenn by Sunpower Inc. of Athens, Ohio.

Application of Landsat Thematic Mapper data for coastal thermal plume analysis at Diablo Canyon

NASA Technical Reports Server (NTRS)

Gibbons, D. E.; Wukelic, G. E.; Leighton, J. P.; Doyle, M. J.

1989-01-01

The possibility of using Landsat Thematic Mapper (TM) thermal data to derive absolute temperature distributions in coastal waters that receive cooling effluent from a power plant is demonstrated. Landsat TM band 6 (thermal) data acquired on June 18, 1986, for the Diablo Canyon power plant in California were compared to ground truth temperatures measured at the same time. Higher-resolution band 5 (reflectance) data were used to locate power plant discharge and intake positions and identify locations of thermal pixels containing only water, no land. Local radiosonde measurements, used in LOWTRAN 6 adjustments for atmospheric effects, produced corrected ocean surface radiances that, when converted to temperatures, gave values within approximately 0.6 C of ground truth. A contour plot was produced that compared power plant plume temperatures with those of the ocean and coastal environment. It is concluded that Landsat can provide good estimates of absolute temperatures of the coastal power plant thermal plume. Moreover, quantitative information on ambient ocean surface temperature conditions (e.g., upwelling) may enhance interpretation of numerical model prediction.

Molecular pathway of near-infrared laser phototoxicity involves ATF-4 orchestrated ER stress

PubMed Central

Khan, Imran; Tang, Elieza; Arany, Praveen

2015-01-01

High power lasers are used extensively in medicine while lower power applications are popular for optical imaging, optogenetics, skin rejuvenation and a therapeutic modality termed photobiomodulation (PBM). This study addresses the therapeutic dose limits, biological safety and molecular pathway of near-infrared (NIR) laser phototoxicity. Increased erythema and tissue damage were noted in mice skin and cytotoxicity in cell cultures at phototoxic laser doses involving generation of reactive oxygen species (ROS) coupled with a rise in surface temperature (>45 °C). NIR laser phototoxicity results from Activating Transcription Factor-4 (ATF-4) mediated endoplasmic reticulum stress and autophagy. Neutralizations of heat or ROS and overexpressing ATF-4 were noted to rescue NIR laser phototoxicity. Further, NIR laser mediated phototoxicity was noted to be non-genotoxic and non-mutagenic. This study outlines the mechanism of NIR laser phototoxicity and the utility of monitoring surface temperature and ATF4 expression as potential biomarkers to develop safe and effective clinical applications. PMID:26030745

Molecular pathway of near-infrared laser phototoxicity involves ATF-4 orchestrated ER stress.

PubMed

Khan, Imran; Tang, Elieza; Arany, Praveen

2015-06-01

High power lasers are used extensively in medicine while lower power applications are popular for optical imaging, optogenetics, skin rejuvenation and a therapeutic modality termed photobiomodulation (PBM). This study addresses the therapeutic dose limits, biological safety and molecular pathway of near-infrared (NIR) laser phototoxicity. Increased erythema and tissue damage were noted in mice skin and cytotoxicity in cell cultures at phototoxic laser doses involving generation of reactive oxygen species (ROS) coupled with a rise in surface temperature (>45 °C). NIR laser phototoxicity results from Activating Transcription Factor-4 (ATF-4) mediated endoplasmic reticulum stress and autophagy. Neutralizations of heat or ROS and overexpressing ATF-4 were noted to rescue NIR laser phototoxicity. Further, NIR laser mediated phototoxicity was noted to be non-genotoxic and non-mutagenic. This study outlines the mechanism of NIR laser phototoxicity and the utility of monitoring surface temperature and ATF4 expression as potential biomarkers to develop safe and effective clinical applications.

Production and uses of liquefied atmosphere (CO2) on Mars

NASA Technical Reports Server (NTRS)

Waldron, R. D.

1991-01-01

Carbon dioxide is universally accessible on Mars, and can be liquefied and separated from residual atmospheric gases by various compress-refrigeration cycles. Liquid CO2, stored under elevated pressures, can be used as a source of high pressure gas for nighttime power generation at a Martian base powered by solar energy during the daytime. Carbon dioxide can also be used for vehicular power. The extractable energy per unit mass of CO2 can exceed that of commercial lead-acid batteries for operating cycles without heat addition. Improved performance is possible using heat input from the ambient atmosphere or thermochemical agents. A unique vehicular application uses pressurized CO2 as a non-combustion low performance propellant for intermediate distance surface transportation. The thermodynamic properties of CO2 are presented with typical operating cycles for the application classes described above.

Electrochemical capacitors: mechanism, materials, systems, characterization and applications.

PubMed

Wang, Yonggang; Song, Yanfang; Xia, Yongyao

2016-10-24

Electrochemical capacitors (i.e. supercapacitors) include electrochemical double-layer capacitors that depend on the charge storage of ion adsorption and pseudo-capacitors that are based on charge storage involving fast surface redox reactions. The energy storage capacities of supercapacitors are several orders of magnitude higher than those of conventional dielectric capacitors, but are much lower than those of secondary batteries. They typically have high power density, long cyclic stability and high safety, and thus can be considered as an alternative or complement to rechargeable batteries in applications that require high power delivery or fast energy harvesting. This article reviews the latest progress in supercapacitors in charge storage mechanisms, electrode materials, electrolyte materials, systems, characterization methods, and applications. In particular, the newly developed charge storage mechanism for intercalative pseudocapacitive behaviour, which bridges the gap between battery behaviour and conventional pseudocapacitive behaviour, is also clarified for comparison. Finally, the prospects and challenges associated with supercapacitors in practical applications are also discussed.

Luneburg lens with extended flat focal surface for electronic scan applications.

PubMed

Li, Ying; Zhu, Qi

2016-04-04

Luneburg lens with flat focal surface has been developed to work together with planar antenna feeds for beam steering applications. According to our analysis of the conventional flattened Luneburg lens, it cannot accommodate enough feeding elements which can cover its whole scan range with half power beamwidths (HPBWs). In this paper, a novel Luneburg lens with extended flat focal surface is proposed based on the theory of Quasi-Conformal Transformation Optics (QCTO), with its beam steering features reserved. To demonstrate this design, a three-dimensional (3D) prototype of this novel extend-flattened Luneburg lens working at Ku band is fabricated based on 3D printing techniques, whose flat focal surface is attached to a 9-element microstrip antenna array to achieve different scan angles. Our measured results show that, with different antenna elements being fed, the HPBWs can cover the whole scan range.

Anatomical medial surfaces with efficient resolution of branches singularities.

PubMed

Gil, Debora; Vera, Sergio; Borràs, Agnés; Andaluz, Albert; González Ballester, Miguel A

2017-01-01

Medial surfaces are powerful tools for shape description, but their use has been limited due to the sensibility of existing methods to branching artifacts. Medial branching artifacts are associated to perturbations of the object boundary rather than to geometric features. Such instability is a main obstacle for a confident application in shape recognition and description. Medial branches correspond to singularities of the medial surface and, thus, they are problematic for existing morphological and energy-based algorithms. In this paper, we use algebraic geometry concepts in an energy-based approach to compute a medial surface presenting a stable branching topology. We also present an efficient GPU-CPU implementation using standard image processing tools. We show the method computational efficiency and quality on a custom made synthetic database. Finally, we present some results on a medical imaging application for localization of abdominal pathologies. Copyright © 2016 Elsevier B.V. All rights reserved.

Enabling Highly Effective Boiling from Superhydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Allred, Taylor P.; Weibel, Justin A.; Garimella, Suresh V.

2018-04-01

A variety of industrial applications such as power generation, water distillation, and high-density cooling rely on heat transfer processes involving boiling. Enhancements to the boiling process can improve the energy efficiency and performance across multiple industries. Highly wetting textured surfaces have shown promise in boiling applications since capillary wicking increases the maximum heat flux that can be dissipated. Conversely, highly nonwetting textured (superhydrophobic) surfaces have been largely dismissed for these applications as they have been shown to promote formation of an insulating vapor film that greatly diminishes heat transfer efficiency. The current Letter shows that boiling from a superhydrophobic surface in an initial Wenzel state, in which the surface texture is infiltrated with liquid, results in remarkably low surface superheat with nucleate boiling sustained up to a critical heat flux typical of hydrophilic wetting surfaces, and thus upends this conventional wisdom. Two distinct boiling behaviors are demonstrated on both micro- and nanostructured superhydrophobic surfaces based on the initial wetting state. For an initial surface condition in which vapor occupies the interstices of the surface texture (Cassie-Baxter state), premature film boiling occurs, as has been commonly observed in the literature. However, if the surface texture is infiltrated with liquid (Wenzel state) prior to boiling, drastically improved thermal performance is observed; in this wetting state, the three-phase contact line is pinned during vapor bubble growth, which prevents the development of a vapor film over the surface and maintains efficient nucleate boiling behavior.

Self-Powered Wireless Smart Sensor Node Enabled by an Ultrastable, Highly Efficient, and Superhydrophobic-Surface-Based Triboelectric Nanogenerator.

PubMed

Zhao, Kun; Wang, Zhong Lin; Yang, Ya

2016-09-27

Wireless sensor networks will be responsible for a majority of the fast growth in intelligent systems in the next decade. However, most of the wireless smart sensor nodes require an external power source such as a Li-ion battery, where the labor cost and environmental waste issues of replacing batteries have largely limited the practical applications. Instead of using a Li-ion battery, we report an ultrastable, highly efficient, and superhydrophobic-surface-based triboelectric nanogenerator (TENG) to scavenge wind energy for sustainably powering a wireless smart temperature sensor node. There is no decrease in the output voltage and current of the TENG after continuous working for about 14 h at a wind speed of 12 m/s. Through a power management circuit, the TENG can deliver a constant output voltage of 3.3 V and a pulsed output current of about 100 mA to achieve highly efficient energy storage in a capacitor. A wireless smart temperature sensor node can be sustainably powered by the TENG for sending the real-time temperature data to an iPhone under a working distance of 26 m, demonstrating the feasibility of the self-powered wireless smart sensor networks.

Natural circulation decay heat removal from an SP-100, 550 kWe power system for a lunar outpost

NASA Technical Reports Server (NTRS)

El-Genk, Mohamed S.; Xue, Huimin

1992-01-01

This research investigated the decay heat removal from the SP-100 reactor core of a 550-kWe power system for a lunar outpost by natural circulation of lithium coolant. A transient model that simulates the decay heat removal loop (DHRL) of the power system was developed and used to assess the system's decay heat removal capability. The effects of the surface area of the decay heat rejection radiator, the dimensions of the decay heat exchanger (DHE) flow duct, the elevation of the DHE, and the diameter of the rise and down pipes in the DHRL on the decay heat removal capability were examined. Also, to determine the applicability of test results at earth gravity to actual system performance on the lunar surface, the effect of the gravity constant (1 g and 1/6 g) on the thermal behavior of the system after shutdown was investigated.

Improvements to Lunar BRDF-Corrected Nighttime Satellite Imagery: Uses and Applications

NASA Technical Reports Server (NTRS)

Cole, Tony A.; Molthan, Andrew L.; Schultz, Lori A.; Roman, Miguel O.; Wanik, David W.

2016-01-01

Observations made by the VIIRS day/night band (DNB) provide daily, nighttime measurements to monitor Earth surface processes.However, these observations are impacted by variations in reflected solar radiation on the moon's surface. As the moon transitions from new to full phase, increasing radiance is reflected to the Earth's surface and contributes additional reflected moonlight from clouds and land surface, in addition to emissions from other light sources observed by the DNB. The introduction of a bi-directional reflectance distribution function (BRDF) algorithm serves to remove these lunar variations and normalize observed radiances. Provided by the Terrestrial Information Systems Laboratory at Goddard Space Flight Center, a 1 km gridded lunar BRDF-corrected DNB product and VIIRS cloud mask can be used for a multitude of nighttime applications without influence from the moon. Such applications include the detection of power outages following severe weather events using pre-and post-event DNB imagery, as well as the identification of boat features to curtail illegal fishing practices. This presentation will provide context on the importance of the lunar BRDF correction algorithm and explore the aforementioned uses of this improved DNB product for applied science applications.

Improvements to Lunar BRDF-Corrected Nighttime Satellite Imagery: Uses and Applications

NASA Astrophysics Data System (ADS)

Cole, T.; Molthan, A.; Schultz, L. A.; Roman, M. O.; Wanik, D. W.

2016-12-01

Observations made by the VIIRS day/night band (DNB) provide daily, nighttime measurements to monitor Earth surface processes. However, these observations are impacted by variations in reflected solar radiation on the moon's surface. As the moon transitions from new to full phase, increasing radiance is reflected to the Earth's surface and contributes additional reflected moonlight from clouds and land surface, in addition to emissions from other light sources observed by the DNB. The introduction of a bi-directional reflectance distribution function (BRDF) algorithm serves to remove these lunar variations and normalize observed radiances. Provided by the Terrestrial Information Systems Laboratory at Goddard Space Flight Center, a 1 km gridded lunar BRDF-corrected DNB product and VIIRS cloud mask can be used for a multitude of nighttime applications without influence from the moon. Such applications include the detection of power outages following severe weather events using pre- and post-event DNB imagery, as well as the identification of boat features to curtail illegal fishing practices. This presentation will provide context on the importance of the lunar BRDF correction algorithm and explore the aforementioned uses of this improved DNB product for applied science applications.

Thermal control requirements for large space structures

NASA Technical Reports Server (NTRS)

Manoff, M.

1978-01-01

Performance capabilities and weight requirements of large space structure systems will be significantly influenced by thermal response characteristics. Analyses have been performed to determine temperature levels and gradients for structural configurations and elemental concepts proposed for advanced system applications ranging from relatively small, low-power communication antennas to extremely large, high-power Satellite Power Systems (SPS). Results are presented for selected platform configurations, candidate strut elements, and potential mission environments. The analyses also incorporate material and surface optical property variation. The results illustrate many of the thermal problems which may be encountered in the development of three systems.

The advances and characteristics of high-power diode laser materials processing

NASA Astrophysics Data System (ADS)

Li, Lin

2000-10-01

This paper presents a review of the direct applications of high-power diode lasers for materials processing including soldering, surface modification (hardening, cladding, glazing and wetting modifications), welding, scribing, sheet metal bending, marking, engraving, paint stripping, powder sintering, synthesis, brazing and machining. The specific advantages and disadvantages of diode laser materials processing are compared with CO 2, Nd:YAG and excimer lasers. An effort is made to identify the fundamental differences in their beam/material interaction characteristics and materials behaviour. Also an appraisal of the future prospects of the high-power diode lasers for materials processing is given.

Lasers for industrial production processing: tailored tools with increasing flexibility

NASA Astrophysics Data System (ADS)

Rath, Wolfram

2012-03-01

High-power fiber lasers are the newest generation of diode-pumped solid-state lasers. Due to their all-fiber design they are compact, efficient and robust. Rofin's Fiber lasers are available with highest beam qualities but the use of different process fiber core sizes enables the user additionally to adapt the beam quality, focus size and Rayleigh length to his requirements for best processing results. Multi-mode fibers from 50μm to 600μm with corresponding beam qualities of 2.5 mm.mrad to 25 mm.mrad are typically used. The integrated beam switching modules can make the laser power available to 4 different manufacturing systems or can share the power to two processing heads for parallel processing. Also CO2 Slab lasers combine high power with either "single-mode" beam quality or higher order modes. The wellestablished technique is in use for a large number of industrial applications, processing either metals or non-metallic materials. For many of these applications CO2 lasers remain the best choice of possible laser sources either driven by the specific requirements of the application or because of the cost structure of the application. The actual technical properties of these lasers will be presented including an overview over the wavelength driven differences of application results, examples of current industrial practice as cutting, welding, surface processing including the flexible use of scanners and classical optics processing heads.

An evolution strategy for lunar nuclear surface power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1992-01-01

The production and transmission of electric power for a permanently inhabited lunar base poses a significant challenge which can best be met through an evolution strategy. Nuclear systems offer the best opportunity for evolution in terms of both life and performance. Applicable nuclear power technology options include isotope systems (either radioisotope thermoelectric generators or dynamic isotope power systems) and reactor systems with either static (thermoelectric or thermionic) or dynamic (Brayton, Stirling, Rankine) conversion. A power system integration approach that takes evolution into account would benefit by reduced development and operations cost, progressive flight experience, and simplified logistics, and would permit unrestrained base expansion. For the purposes of defining a nuclear power system evolution strategy, the lunar base development shall consist of four phases: precursor, emplacement, consolidation, and operations.

Emulating DC constant power load: a robust sliding mode control approach

NASA Astrophysics Data System (ADS)

Singh, Suresh; Fulwani, Deepak; Kumar, Vinod

2017-09-01

This article presents emulation of a programmable power electronic, constant power load (CPL) using a dc/dc step-up (boost) converter. The converter is controlled by a robust sliding mode controller (SMC). A novel switching surface is proposed to ensure a required power sunk by the converter. The proposed dc CPL is simple in design, has fast dynamic response and high accuracy, and offers an inexpensive alternative to study converters for cascaded dc distribution power system applications. Furthermore, the proposed CPL is sufficiently robust against the input voltage variations. A laboratory prototype of the proposed dc CPL has been developed and validated with SMC realised through OPAL-RT platform. The capability of the proposed dc CPL is confirmed via experimentations in varied scenarios.

Light transmittance and surface roughness of a feldspathic ceramic CAD-CAM material as a function of different surface treatments.

PubMed

Ural, Çağrı; Duran, İbrahim; Evmek, Betül; Kavut, İdris; Cengiz, Seda; Yuzbasioglu, Emir

2016-07-15

The aim of the present study was to determine the effect of different surface treatments on light transmission of aesthetic feldspathic ceramics used in CAD-CAM chairside restorations. Forty eight feldspatic ceramic test specimens were prepared from prefabricated CAD-CAM blocks by using a slow speed diamond saw. Test specimens were prepared and divided into 4 groups (n = 12). In the control group, no surface treatments were applied on the feldspathic ceramic surfaces. In the hydrofluoric acid group, the bonding surfaces of feldspathic ceramics were etched with 9.5 % hydrofluoric acid. In the sandblasting group the feldspathic ceramic surfaces were air-abraded with 30-μm alumium oxide (Al2O3) particles and Er:YAG laser was used to irradiate the ceramic surfaces. The incident light power given by the LED device and the transmitted light power through each ceramic sample was registered using a digital LED radiometer device. Each polymerization light had a light guide with 8-mm-diameter tips. Light transmission of feldspathic ceramic samples was determined by placing it on the radiometer and irradiating the specimen for 10 s at the highest setting for each light polymerization. All specimens were coated with gold using a sputter coater and examined under a field emission scanning electron microscope. Surface roughness measurement each group were evaluated with 3D optical surface and tactile profilometers. One-way ANOVA test results revealed that both surface conditioning method significantly affect the light transmittance (F:412.437; p < 0.001) and the surface roughness values (F:16.386; p < 0.001). Al2O3 and Er-YAG laser application reduced the light transmission significantly (p < 0.05). The laser and Al2O3 applications reduced the light transmission of 1.5 mm thickness feldspathic ceramic material below the value of 400 mW/cm(2) which is critical limit for safe polymerization.

Application of Reflected Global Navigation Satellite System (GNSS-R) Signals in the Estimation of Sea Roughness Effects in Microwave Radiometry

NASA Technical Reports Server (NTRS)

Voo, Justin K.; Garrison, James L.; Yueh, Simon H.; Grant, Michael S.; Fore, Alexander G.; Haase, Jennifer S.; Clauss, Bryan

2010-01-01

In February-March 2009 NASA JPL conducted an airborne field campaign using the Passive Active L-band System (PALS) and the Ku-band Polarimetric Scatterometer (PolSCAT) collecting measurements of brightness temperature and near surface wind speeds. Flights were conducted over a region of expected high-speed winds in the Atlantic Ocean, for the purposes of algorithm development for salinity retrievals. Wind speeds encountered were in the range of 5 to 25 m/s during the two weeks deployment. The NASA-Langley GPS delay-mapping receiver (DMR) was also flown to collect GPS signals reflected from the ocean surface and generate post-correlation power vs. delay measurements. This data was used to estimate ocean surface roughness and a strong correlation with brightness temperature was found. Initial results suggest that reflected GPS signals, using small low-power instruments, will provide an additional source of data for correcting brightness temperature measurements for the purpose of sea surface salinity retrievals.

A lifting-surface theory solution for the diffraction of internal sound sources by an engine nacelle

NASA Astrophysics Data System (ADS)

Martinez, R.

1986-07-01

Lifting-surface theory is used to solve the problem of diffraction by a rigid open-ended pipe of zero thickness and finite length, with application to the prediction of acoustic insertion-loss performance for the encasing structure of a ducted propeller or turbofan. An axisymmetric situation is assumed, and the incident field due to a force applied directly to the fluid in the cylinder axial direction is used. A virtual-source distribution of unsteady dipoles is found whose integrated component of radial velocity is set to cancel that of the incident field over the surface. The calculated virtual load is verified by whether its effect on the near-field input power at the actual source is consistent with the far-field power radiated by the system, a balance which is possible if the no-flow-through boundary condition has been satisfied over the rigid pipe surface such that the velocity component of the acoustic intensity is zero.

SMART Power Systems for ANTS Missions

NASA Astrophysics Data System (ADS)

Clark, P. E.; Floyd, S. R.; Curtis, S. A.; Rilee, M. L.

2005-02-01

Autonomous NanoTechnology Swarm (ANTS) Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in space. ART systems based on currently available electromechanical (EMS) technology could support human crews on the lunar surface within the next 10 to 15 years. Two or more decades from now, NEMS (Super Miniaturized ART or SMART) technology could perform fully autonomous surveys and operations beyond the reach of human crews. Power system requirements would range from 1 kg to generate tens of Watts for near term ART applications, such as a lunar or Mars Lander Amorphous Rover Antenna (LARA), to <0.1 kg to generate hundreds of mWatts for more advanced SMART applications.

Supporting Energy-Related Societal Applications Using NASA's Satellite and Modeling Data

NASA Technical Reports Server (NTRS)

Stackhouse, Paul W., Jr.; Whitlock, C. H.; Chandler, W. S.; Hoell, J. M.; Zhang, T.; Mikovitz, J. C.; Leng, G. S.; Lilienthal, P.

2006-01-01

Improvements to NASA Surface Meteorology and Solar Energy (SSE) web site are now being made through the Prediction of Worldwide Energy Resource (POWER) project under NASA Science Mission Directorate Applied Science Energy Management Program. The purpose of this project is to tailor NASA Science Mission results for energy sector applications and decision support systems. The current status of SSE and research towards upgrading estimates of total, direct and diffuse solar irradiance from NASA satellite measurements and analysis are discussed. Part of this work involves collaborating with partners such as the National Renewable Energy Laboratory (NREL) and the Natural Resources Canada (NRCan). Energy Management and POWER plans including historic, near-term and forecast datasets are also overviewed.

Fuel Cell Activities at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Lyons, Valerie (Technical Monitor)

2002-01-01

Fuel cells have a long history in space applications and may have potential application in aeronautics as well. A fuel cell is an electrochemical energy conversion device that directly transforms the chemical energy of a fuel and oxidant into electrical energy. Alkaline fuel cells have been the mainstay of the U.S. space program, providing power for the Apollo missions and the Space Shuttle. However, Proton Exchange Membrane (PEM) fuel cells offer potential benefits over alkaline systems and are currently under development for the next generation Reusable Launch Vehicle (RLV). Furthermore, primary and regenerative systems utilizing PEM technology are also being considered for future space applications such as surface power and planetary aircraft. In addition to these applications, the NASA Glenn Research Center is currently studying the feasibility of the use of both PEM and solid oxide fuel cells for low- or zero-emission electric aircraft propulsion. These types of systems have potential applications for high altitude environmental aircraft, general aviation and commercial aircraft, and high attitude airships. NASA Glenn has a unique set of capabilities and expertise essential to the successful development of advanced fuel cell power systems for space and aeronautics applications. NASA Glenn's role in past fuel cell development programs as well as current activities to meet these new challenges will be presented

75 FR 11153 - Free Flow Power Qualified Hydro 22, LLC; Notice of Preliminary Permit Application Accepted for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-10

... water surface elevation of 609 feet mean sea level; (3) an new 54-foot-long by 74-foot-wide powerhouse to contain two new turbine- generator units for a total installed capacity of 5.0 megawatts; (4) a...

A GLOBAL ASSESSMENT OF SOLAR ENERGY RESOURCES: NASA's Prediction of Worldwide Energy Resources (POWER) Project

NASA Astrophysics Data System (ADS)

Zhang, T.; Stackhouse, P. W., Jr.; Chandler, W.; Hoell, J. M.; Westberg, D.; Whitlock, C. H.

2010-12-01

NASA's POWER project, or the Prediction of the Worldwide Energy Resources project, synthesizes and analyzes data on a global scale. The products of the project find valuable applications in the solar and wind energy sectors of the renewable energy industries. The primary source data for the POWER project are NASA's World Climate Research Project (WCRP)/Global Energy and Water cycle Experiment (GEWEX) Surface Radiation Budget (SRB) project (Release 3.0) and the Global Modeling and Assimilation Office (GMAO) Goddard Earth Observing System (GEOS) assimilation model (V 4.0.3). Users of the POWER products access the data through NASA's Surface meteorology and Solar Energy (SSE, Version 6.0) website (http://power.larc.nasa.gov). Over 200 parameters are available to the users. The spatial resolution is 1 degree by 1 degree now and will be finer later. The data covers from July 1983 to December 2007, a time-span of 24.5 years, and are provided as 3-hourly, daily and monthly means. As of now, there have been over 18 million web hits and over 4 million data file downloads. The POWER products have been systematically validated against ground-based measurements, and in particular, data from the Baseline Surface Radiation Network (BSRN) archive, and also against the National Solar Radiation Data Base (NSRDB). Parameters such as minimum, maximum, daily mean temperature and dew points, relative humidity and surface pressure are validated against the National Climate Data Center (NCDC) data. SSE feeds data directly into Decision Support Systems including RETScreen International clean energy project analysis software that is written in 36 languages and has greater than 260,000 users worldwide.

Analytical close-form solutions to the elastic fields of solids with dislocations and surface stress

NASA Astrophysics Data System (ADS)

Ye, Wei; Paliwal, Bhasker; Ougazzaden, Abdallah; Cherkaoui, Mohammed

2013-07-01

The concept of eigenstrain is adopted to derive a general analytical framework to solve the elastic field for 3D anisotropic solids with general defects by considering the surface stress. The formulation shows the elastic constants and geometrical features of the surface play an important role in determining the elastic fields of the solid. As an application, the analytical close-form solutions to the stress fields of an infinite isotropic circular nanowire are obtained. The stress fields are compared with the classical solutions and those of complex variable method. The stress fields from this work demonstrate the impact from the surface stress when the size of the nanowire shrinks but becomes negligible in macroscopic scale. Compared with the power series solutions of complex variable method, the analytical solutions in this work provide a better platform and they are more flexible in various applications. More importantly, the proposed analytical framework profoundly improves the studies of general 3D anisotropic materials with surface effects.

Laser dispersing of ceramic powders into Al-alloys

NASA Astrophysics Data System (ADS)

Jendrzejewski, Rafał; Van Acker, Karel; Vanhoyweghen, Dirk

2007-02-01

The general objective of the work was formation of highly wear resistant metal matrix composite (MMC) surface layers on aluminium based Al 6061 alloy by means of laser dispersing. The surface of the substrate is locally melted by the high power diode laser beam and simultaneously powder particles are injected into molten material. The optimal process parameter window for the laser dispersing of SiC in Al 6061 has been found. The measured values of the wear rates of the sample with dispersed SiC particles are about seven times lower than that of the reference Al-substrates. Results show that laser dispersing is highly promising technology to improve the surface, mainly wear properties of light metals. However the possibilities of industrial application are still limited due to considerable laser beam power and preheating temperature applied as well low productivity because of low scanning speed, and therefore further investigations are required.

Study of gain-coupled distributed feedback laser based on high order surface gain-coupled gratings

NASA Astrophysics Data System (ADS)

Gao, Feng; Qin, Li; Chen, Yongyi; Jia, Peng; Chen, Chao; Cheng, LiWen; Chen, Hong; Liang, Lei; Zeng, Yugang; Zhang, Xing; Wu, Hao; Ning, Yongqiang; Wang, Lijun

2018-03-01

Single-longitudinal-mode, gain-coupled distributed feedback (DFB) lasers based on high order surface gain-coupled gratings are achieved. Periodic surface metal p-contacts with insulated grooves realize gain-coupled mechanism. To enhance gain contrast in the quantum wells without the introduction of effective index-coupled effect, groove length and depth were well designed. Our devices provided a single longitudinal mode with the maximum CW output power up to 48.8 mW/facet at 971.31 nm at 250 mA without facet coating, 3dB linewidth (<3.2 pm) and SMSR (>39 dB). Optical bistable characteristic was observed with a threshold current difference. Experimentally, devices with different cavity lengths were contrasted on power-current and spectrum characteristics. Due to easy fabrication technique and stable performance, it provides a method of fabricating practical gain-coupled distributed feedback lasers for commercial applications.

Three-Dimensional Porous Particles Composed of Curved, Two-Dimensional, Nano-Sized Layers for Li-Ion Batteries

NASA Technical Reports Server (NTRS)

Yushin, Gleb; Evanoff, Kara; Magasinski, Alexander

2012-01-01

Thin Si films coated on porous 3D particles composed of curved 2D graphene sheets have been synthesized utilizing techniques that allow for tunable properties. Since graphene exhibits specific surface area up to 100 times higher than carbon black or graphite, the deposition of the same mass of Si on graphene is much faster in comparison -- a factor which is important for practical applications. In addition, the distance between graphene layers is tunable and variation in the thickness of the deposited Si film is feasible. Both of these characteristics allow for optimization of the energy and power characteristics. Thicker films will allow higher capacity, but slower rate capabilities. Thinner films will allow more rapid charging, or higher power performance. In this innovation, uniform deposition of Si and C layers on high-surface area graphene produced granules with specific surface area (SSA) of 5 sq. m/g.

Ultra high performance connectors for power transmission applications

DOEpatents

Wang, Jy-An; Ren, Fei; Lee, Dominic F; Jiang, Hao

2014-03-04

Disclosed are several examples of an apparatus for connecting the free ends of two electrical power transmission lines having conductor strands disposed around a central, reinforcing core. The examples include an inner sleeve having a body defining an inner bore passing through an axially-extending, central axis, an outer rim surface disposed radially outward from the central bore, and one or more axially-extending grooves penetrating the body at the outer rim surface. Also included is an outer splice having a tubular shaped body with a bore passing coaxially through the central axis, the bore defining an inner rim surface for accepting the inner sleeve. The inner bore of the inner sleeve accepts the reinforcement cores of the two conductors, and the grooves accept the conductor strands in an overlapping configuration so that a majority of the electrical current flows between the overlapped conductor strands when the conductors are transmitting electrical current.

Quantification of air plasma chemistry for surface disinfection

NASA Astrophysics Data System (ADS)

Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

2014-12-01

Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.

Experimental Investigation on the Detection of Multiple Surface Cracks Using Vibrothermography with a Low-Power Piezoceramic Actuator

PubMed Central

Xu, Changhang; Xie, Jing; Zhang, Wuyang; Kong, Qingzhao; Chen, Guoming; Song, Gangbing

2017-01-01

Vibrothermography often employs a high-power actuator to generate heat on a specimen to reveal damage, however, the high-power actuator brings inconvenience to the application and possibly introduces additional damage to the inspected objects. This study uses a low-power piezoceramic transducer as the actuator of vibrothermography and explores its ability to detect multiple surface cracks in a metal part. Experiments were conducted on a thin aluminum beam with three cracks in different orientations. Detailed analyses of both thermograms and temperature data are presented to validate the proposed vibrothermography method. To further investigate the performance of the proposed vibrothermography method, we experimentally studied the effects of several critical factors, including the amplitude of excitation signal, specimen constraints, relative position between the transducer and cracks (the transducer is mounted on the same or the opposite side with the cracks). The results demonstrate that all cracks can be detected conveniently and simultaneously by using the proposed low-power vibrothermography. We also found that the magnitude of excitation signal and the specimen constraints have a great influence on detection results. Combined with effective data processing methods, such as Fourier transformation employed in this study, the proposed method provides a promising potential to detect multiple cracks on a metal surface in a safe and effective manner. PMID:29168759

Extensibility of the fission surface power (FSP) system from the moon to Mars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poston, David Irvin

2011-01-28

Fission reactors have great near-term potential to power human and robotic missions/outposts on the surface of the Moon and Mars (and potentially other planets, moons, and asteroids). The ability to provide a power-rich environment that is independent of solar intensity, nights, dust storms, etc., is of significant (perhaps enabling) importance to the further expansion of humans into our solar system. NASA's Reference Fission Surface Power (FSP) System is a 40 kWe system that has been primarily designed for lunar applications. This paper examines the extensibility of the FSP design and technology for potential missions on Mars. Possible impacts include themore » effects of changes in heat sink, gravity, day-night cycles, mission transit time, communication delay, and the chemistry of the regolith and atmosphere. One of the biggest impacts might be differences in the potential utilization of in-situ materials for shielding. Another major factor is that different missions will likely require different performance requirements, e.g. power, lifetime and mass. This paper concludes that the environmental differences between potential mission locations will not require significant changes in design and technologies, unless performance requirements for a specific mission are substantially different than those adopted for the FSP The primary basis for this conclusion is that the FSP has been designed with robust materials and design margins.« less

Development of High-power LED Lighting Luminaires Using Loop Heat Pipe

NASA Astrophysics Data System (ADS)

Huang, Bin-Juine; Huang, Huan-Hsiang; Chen, Chun-Wei; Wu, Min-Sheng

High-power LED should reject about 6 times of heat of the conventional lighting device and keep the LED junction temperature below 80°C to assure reliability and low light decay. In addition, no fan is allowed and the heat dissipation design should not interfere with the industrial design of lighting fixture and have a light weight. This thus creates an extreme thermal management problem. The present study has shown that, using a special heat dissipation technology (loop heat pipe), the high-power LED lighting luminaire with input power from 36 to 150W for outdoor and indoor applications can be achieved with light weight, among 0.96 to 1.57 kg per 1,000 lumen of net luminous flux output from the luminaire. The loop heat pipe uses a flexible connecting pipe as the condenser which can be wounded around the reflector of the luminaire to dissipate the heat to the ambient air by natural convection. For roadway or street lighting application, the present study shows that a better optical design of LED lamps can further result in power consumption reduction, based on the same illumination on road surface. The high-power LED luminaries developed in the present study have shown that the energy saving is > 50% in road lighting applications as compared to sodium light or > 70% compared to mercury light.

AFM surface imaging of AISI D2 tool steel machined by the EDM process

NASA Astrophysics Data System (ADS)

Guu, Y. H.

2005-04-01

The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM.

Design Development Analyses in Support of a Heatpipe-Brayton Cycle Heat Exchanger

NASA Technical Reports Server (NTRS)

Steeve, Brian; VanDyke, Melissa; Majumdar, Alok; Nguyen, Dalton; Corley, Melissa; Guffee, Ray M.; Kapernick, Richard J.

2003-01-01

One of the power systems under consideration for nuclear electric propulsion or as a planetary surface power source is a heatpipe-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the heatpipes to the Brayton gas via a heat exchanger attached to the heatpipes. This paper discusses the fluid, thermal and structural analyses that were performed in support of the design of the heat exchanger to be tested in the SAFE-100 experimental program at Marshall Space Flight Center. A companion paper, "Mechanical Design and Fabrication of a SAFE-100 Heat Exchanger for use in NASA s Advanced Propulsion Thermal-hydraulic Simulator", presents the fabrication issues and prototyping studies that, together with these analyses, led to the development of this heat exchanger. An important consideration throughout the design development of the heat exchanger was its capability to be utilized for higher power and temperature applications. This paper also discusses this aspect of the design and presents designs for specific applications that are under consideration.

Recycled tire crumb rubber anodes for sustainable power production in microbial fuel cells

NASA Astrophysics Data System (ADS)

Wang, Heming; Davidson, Matthew; Zuo, Yi; Ren, Zhiyong

One of the greatest challenges facing microbial fuel cells (MFCs) in large scale applications is the high cost of electrode material. We demonstrate here that recycled tire crumb rubber coated with graphite paint can be used instead of fine carbon materials as the MFC anode. The tire particles showed satisfactory conductivity after 2-4 layers of coating. The specific surface area of the coated rubber was over an order of magnitude greater than similar sized graphite granules. Power production in single chamber tire-anode air-cathode MFCs reached a maximum power density of 421 mW m -2, with a coulombic efficiency (CE) of 25.1%. The control graphite granule MFC achieved higher power density (528 mW m -2) but lower CE (15.6%). The light weight of tire particle could reduce clogging and maintenance cost but posts challenges in conductive connection. The use of recycled material as the MFC anodes brings a new perspective to MFC design and application and carries significant economic and environmental benefit potentials.

Observations of electron heating during 28 GHz microwave power application in proto-MPEX

DOE PAGES

Biewer, Theodore M.; Bigelow, Tim S.; Caneses Marin, Juan F.; ...

2018-02-01

The Prototype Material Plasma Exposure Experiment at the Oak Ridge National Laboratory utilizes a variety of power systems to generate and deliver a high heat flux plasma onto the surface of material targets. In the experiments described here, a deuterium plasma is produced via a ~100 kW, 13.56 MHz RF helicon source, to which ~20 kW of 28 GHz microwave power is applied. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is centrally peaked. In the core of the plasma column, the electron density is higher than themore » cut-off density (~0.9 × 1019 m -3) for the launched mixture of X- and O-mode electron cyclotron heating waves to propagate. TS measurements indicate electron temperature increases from ~5 eV to ~20 eV during 28 GHz power application when the neutral deuterium pressure is reduced below 0.13 Pa (~1 mTorr.).« less

Observations of electron heating during 28 GHz microwave power application in proto-MPEX

NASA Astrophysics Data System (ADS)

Biewer, T. M.; Bigelow, T. S.; Caneses, J. F.; Diem, S. J.; Green, D. L.; Kafle, N.; Rapp, J.; Proto-MPEX Team

2018-02-01

The Prototype Material Plasma Exposure Experiment at the Oak Ridge National Laboratory utilizes a variety of power systems to generate and deliver a high heat flux plasma onto the surface of material targets. In the experiments described here, a deuterium plasma is produced via a ˜100 kW, 13.56 MHz RF helicon source, to which ˜20 kW of 28 GHz microwave power is applied. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is centrally peaked. In the core of the plasma column, the electron density is higher than the cut-off density (˜0.9 × 1019 m-3) for the launched mixture of X- and O-mode electron cyclotron heating waves to propagate. TS measurements indicate electron temperature increases from ˜5 eV to ˜20 eV during 28 GHz power application when the neutral deuterium pressure is reduced below 0.13 Pa (˜1 mTorr.).

New configuration for efficient and durable copper coating on the outer surface of a tube

DOE PAGES

Ahmad, Irfan; Chapman, Steven F.; Velas, Katherine M.; ...

2017-03-27

A well-adhered copper coating on stainless steel power coupler parts is required in superconducting radio frequency (SRF) accelerators. Radio frequency power coupler parts are complex, tubelike stainless steel structures, which require copper coating on their outer and inner surfaces. Conventional copper electroplating sometimes produces films with inadequate adhesion strength for SRF applications. Electroplating also requires a thin nickel strike layer under the copper coating, whose magnetic properties can be detrimental to SRF applications. Coaxial energetic deposition (CED) and sputtering methods have demonstrated efficient conformal coating on the inner surfaces of tubes but coating the outer surface of a tube ismore » challenging because these coating methods are line of sight. When the substrate is off axis and the plasma source is on axis, only a small section of the substrate’s outer surface is exposed to the source cathode. The conventional approach is to rotate the tube to achieve uniformity across the outer surface. This method results in poor film thickness uniformity and wastes most of the source plasma. Alameda Applied Sciences Corporation (AASC) has developed a novel configuration called hollow external cathode CED (HEC-CED) to overcome these issues. HEC-CED produces a film with uniform thickness and efficiently uses all eroded source material. Furthermore, the Cu film deposited on the outside of a stainless steel tube using the new HEC-CED configuration survived a high pressure water rinse adhesion test. HEC-CED can be used to coat the outside of any cylindrical structure.« less

New configuration for efficient and durable copper coating on the outer surface of a tube

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Irfan; Chapman, Steven F.; Velas, Katherine M.

A well-adhered copper coating on stainless steel power coupler parts is required in superconducting radio frequency (SRF) accelerators. Radio frequency power coupler parts are complex, tubelike stainless steel structures, which require copper coating on their outer and inner surfaces. Conventional copper electroplating sometimes produces films with inadequate adhesion strength for SRF applications. Electroplating also requires a thin nickel strike layer under the copper coating, whose magnetic properties can be detrimental to SRF applications. Coaxial energetic deposition (CED) and sputtering methods have demonstrated efficient conformal coating on the inner surfaces of tubes but coating the outer surface of a tube ismore » challenging because these coating methods are line of sight. When the substrate is off axis and the plasma source is on axis, only a small section of the substrate’s outer surface is exposed to the source cathode. The conventional approach is to rotate the tube to achieve uniformity across the outer surface. This method results in poor film thickness uniformity and wastes most of the source plasma. Alameda Applied Sciences Corporation (AASC) has developed a novel configuration called hollow external cathode CED (HEC-CED) to overcome these issues. HEC-CED produces a film with uniform thickness and efficiently uses all eroded source material. Furthermore, the Cu film deposited on the outside of a stainless steel tube using the new HEC-CED configuration survived a high pressure water rinse adhesion test. HEC-CED can be used to coat the outside of any cylindrical structure.« less

Realization of Multi-Stable Ground States in a Nematic Liquid Crystal by Surface and Electric Field Modification

NASA Astrophysics Data System (ADS)

Gwag, Jin Seog; Kim, Young-Ki; Lee, Chang Hoon; Kim, Jae-Hoon

2015-06-01

Owing to the significant price drop of liquid crystal displays (LCDs) and the efforts to save natural resources, LCDs are even replacing paper to display static images such as price tags and advertising boards. Because of a growing market demand on such devices, the LCD that can be of numerous surface alignments of directors as its ground state, the so-called multi-stable LCD, comes into the limelight due to the great potential for low power consumption. However, the multi-stable LCD with industrial feasibility has not yet been successfully performed. In this paper, we propose a simple and novel configuration for the multi-stable LCD. We demonstrate experimentally and theoretically that a battery of stable surface alignments can be achieved by the field-induced surface dragging effect on an aligning layer with a weak surface anchoring. The simplicity and stability of the proposed system suggest that it is suitable for the multi-stable LCDs to display static images with low power consumption and thus opens applications in various fields.

A comparison of radioisotope Brayton and Stirling systems for lunar surface mobile power

NASA Astrophysics Data System (ADS)

Harty, Richard B.

A study was performed by the Rocketdyne Division of Rockwell International on a 2.5-kWe modular dynamic isotope power system (DIPS) using a Stirling power conversion system. The results of this study were compared with similar results performed under the DIPS program using a Brayton power conversion system. The application considered was for lunar mobile power sources in the power range of 2.5 kWe to 15 kWe. The study indicated that the Stirling power module has 20 percent lower mass and 40 percent lower radiator area than the Brayton module. However, the study also revealed that because the Stirling power module requires a complex heat pipe arrangement to transport heat from the isotope to the Stirling heater head and a pumped NaK heat rejection loop, the Stirling module is much more difficult to integrate with the isotope heat source and heat rejection system.

POwer WithOut Wire (POWOW): A SEP Concept for Space Exploration

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W., Jr.; ONeill, Mark

2000-01-01

Electric propulsion has emerged as a cost-effective solution to a wide range of satellite applications. Deep Space 1 demonstrated electric propulsion as a primary propulsion source for a spacecraft. The POwer WithOut Wires (POWOW) concept has been developed as a solar electric propelled spacecraft that would travel to Mars, for example, enter selenosynchronous orbit and then use lasers to beam power to surface installations. This concept has been developed with industrial expertise in high efficiency solar cells, advanced concentrator modules, innovative arrays, and high power electric propulsion systems. The paper will present the latest version of the spacecraft, the technologies involved, possible missions and trip times to Mars and laser beaming options. The POWOW spacecraft is a general purpose solar electric propulsion system that includes technologies that are directly applicable to commercial and government spacecraft with power levels ranging from 4 kW in Low Earth Orbits (LEO) to about 1 MW. The system is modular and expandable. Learning curve costing methodologies are used to demonstrate cost effectiveness of a modular system.

Analysis of Laser Injection Condition and Electrical Properties in Local BSF for Laser Fired Contact c-Si Solar Cell Applications.

PubMed

Park, Cheolmin; Choi, Gyuho; Balaji, Nagarajan; Ju, Minkyu; Lee, Youn-Jung; Lee, Haeseok; Yi, Junsin

2018-07-01

A crystalline silicon (c-Si) local-back-contact (LBC) solar cell for which a laser-condition-optimized surface-recombination velocity (SRV), a contact resistance (Rc), and local back surface fields (LBSFs) were utilized is reported. The effect of the laser condition on the rear-side electrical properties of the laser-fired LBC solar cell was studied. The Nd:YAG-laser (1064-nm wavelength) power and frequency were varied to obtain LBSF values with a lower contact resistance. A 10-kHz laser power of 44 mW resulted in an Rc of 0.125 ohms with an LBSF thickness of 2.09 μm and a higher open-circuit voltage (VOC) of 642 mV.

Bending and splitting of spoof surface acoustic waves through structured rigid surface

NASA Astrophysics Data System (ADS)

Xie, Sujun; Ouyang, Shiliang; He, Zhaojian; Wang, Xiaoyun; Deng, Ke; Zhao, Heping

2018-03-01

In this paper, we demonstrated that a 90°-bended imaging of spoof surface acoustic waves with subwavelength resolution of 0.316λ can be realized by a 45° prism-shaped surface phononic crystal (SPC), which is composed of borehole arrays with square lattice in a rigid plate. Furthermore, by combining two identical prism-shaped phononic crystal to form an interface (to form a line-defect), the excited spoof surface acoustic waves can be split into bended and transmitted parts. The power ratio between the bended and transmitted surface waves can be tuned arbitrarily by adjusting the defect size. This acoustic system is believed to have potential applications in various multifunctional acoustic solutions integrated by different acoustical devices.

Increase of porosity by combining semi-carbonization and KOH activation of formaldehyde resins to prepare high surface area carbons for supercapacitor applications

NASA Astrophysics Data System (ADS)

Heimböckel, Ruben; Kraas, Sebastian; Hoffmann, Frank; Fröba, Michael

2018-01-01

A series of porous carbon samples were prepared by combining a semi-carbonization process of acidic polymerized phenol-formaldehyde resins and a following chemical activation with KOH used in different ratios to increase specific surface area, micropore content and pore sizes of the carbons which is favourable for supercapacitor applications. Samples were characterized by nitrogen physisorption, powder X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The results show that the amount of KOH, combined with the semi-carbonization step had a remarkable effect on the specific surface area (up to SBET: 3595 m2 g-1 and SDFT: 2551 m2 g-1), pore volume (0.60-2.62 cm3 g-1) and pore sizes (up to 3.5 nm). The carbons were tested as electrode materials for electrochemical double layer capacitors (EDLC) in a two electrode setup with tetraethylammonium tetrafluoroborate in acetonitrile as electrolyte. The prepared carbon material with the largest surface area, pore volume and pore sizes exhibits a high specific capacitance of 145.1 F g-1 at a current density of 1 A g-1. With a high specific energy of 31 W h kg-1 at a power density of 33028 W kg-1 and a short time relaxation constant of 0.29 s, the carbon showed high power capability as an EDLC electrode material.

Thermographic Inspections Save Skins and Prevent Blackouts

NASA Technical Reports Server (NTRS)

2003-01-01

Scanning thermography involves heating a component s surface and subsequently measuring the surface temperature, using an infrared camera to identify structural defects such as corrosion and disbonding. It is a completely noninvasive and noncontacting process. Scans can detect defects in conventional metals and plastics, as well as in bonded aluminum composites, plastic- and resinbased composites, and laminated structures. The apparatus used for scanning is highly portable and can cover the surface of a test material up to six times faster than conventional thermography. NASA scientists affirm that the technology is an invaluable asset to the airlines, detecting potential defects that can cause structural failure.In 1996, ThermTech Services, Inc., of Stuart, Florida, approached NASA in an effort to evaluate the technology for application in the power and process industries, where corrosion is of serious concern. ThermTech Services proceeded to develop the application for inspecting boiler waterwall tubing at fossil-fueled electric-generating stations. In 1999, ThermTech purchased the rights to NASA s patented technology and developed the specialized equipment required to apply the inspecting method to power plant components. The ThermTech robotic system using NASA technology has proved to be extremely successful and cost effective in performing detailed inspections of large structures such as boiler waterwalls and aboveground chemical storage tanks. It is capable of inspecting a waterwall, tank-wall, or other large surfaces at a rate of approximately 10 square feet per minute or faster.

A novel trapezoid fin pattern applicable for air-cooled heat sink

NASA Astrophysics Data System (ADS)

Chen, Chien-Hung; Wang, Chi-Chuan

2015-11-01

The present study proposed a novel step or trapezoid surface design applicable to air-cooled heat sink under cross flow condition. A total of five heat sinks were made and tested, and the corresponding fin patterns are (a) plate fin; (b) step fin (step 1/3, 3 steps); (c) 2-step fin (step 1/2, 2 steps); (d) trapezoid fin (trap 1/3, cutting 1/3 length from the rear end) and (e) trapezoid fin (trap 1/2, cutting 1/2 length from the rear end). The design is based on the heat transfer augmentation via (1) longer perimeter of entrance region and (2) larger effective temperature difference at the rear part of the heat sink. From the test results, it is found that either step or trapezoid design can provide a higher heat transfer conductance and a lower pressure drop at a specified frontal velocity. The effective conductance of trap 1/3 design exceeds that of plate surface by approximately 38 % at a frontal velocity of 5 m s-1 while retains a lower pressure drop of 20 % with its surface area being reduced by 20.6 %. For comparisons exploiting the overall thermal resistance versus pumping power, the resultant thermal resistance of the proposed trapezoid design 1/3, still reveals a 10 % lower thermal resistance than the plate fin surface at a specified pumping power.

Great Lakes Regional Phase 3 Commercialization Conference, Held in Detroit, Michigan on May 23 - 25, 1994

DTIC Science & Technology

1994-05-25

small highly efficient power systems to provide electricity for space applications. These converters are solar heated for near earth orbit applications...processing in NASA’s Wake Shield Facility. AMPS plans to complete product development in each of these specific technology areas utilizing SBIR...Corrosion: Crevice corrosion is a form of localized corrosion that occurs within crevices or shielded surfaces where stagnant solution is present

ALD anti-reflection coatings at 1ω, 2ω, 3ω, and 4ω for high-power ns-laser application

NASA Astrophysics Data System (ADS)

Liu, Hao; Jensen, Lars; Ma, Ping; Ristau, Detlev

2018-04-01

Atomic layer deposition (ALD) facilitates the deposition of coatings with precise thickness, high surface conformity, structural uniformity, and nodular-free structure, which are properties desired in high-power laser coatings. ALD was studied to produce uniform and stable Al2O3 and HfO2 single layers and was employed to produce anti-reflection coatings for the harmonics (1ω, 2ω, 3ω, and 4ω) of the Nd:YAG laser. In order to qualify the ALD films for high-power laser applications, the band gap energy, absorption, and element content of single layers were characterized. The damage tests of anti-reflection coatings were carried out with a laser system operated at 1ω, 2ω, 3ω, and 4ω, respectively. The damage mechanism was discussed by analyzing the damage morphology and electric field intensity difference. ALD coatings exhibit stable growth rates, low absorption, and rather high laser-induced damage threshold (LIDT). The LIDT is limited by HfO2 as the employed high-index material. These properties indicate the high versatility of ALD films for applications in high-power coatings.

Experience of high-nitrogenous steel powder application in repairs and surface hardening of responsible parts for power equipment by plasma spraying

NASA Astrophysics Data System (ADS)

Kolpakov, A. S.; Kardonina, N. I.

2016-02-01

The questions of the application of novel diffusion-alloying high-nitrogenous steel powders for repair and surface hardening of responsible parts of power equipment by plasma spraying are considered. The appropriateness of the method for operative repair of equipment and increasing its service life is justified. General data on the structure, properties, and manufacture of nitrogen-, aluminum-, and chromium-containing steel powders that are economically alloyed using diffusion are described. It is noted that the nitrogen release during the decomposition of iron nitrides, when heating, protects the powder particles from oxidation in the plasma jet. It is shown that the coating retains 50% of nitrogen that is contained in the powder. Plasma spraying modes for diffusion-alloying high-nitrogenous steel powders are given. The service properties of plasma coatings based on these powders are analyzed. It is shown that the high-nitrogenous steel powders to a nitrogen content of 8.9 wt % provide the necessary wear resistance and hardness of the coating and the strength of its adhesion to the substrate and corrosion resistance to typical aggressive media. It is noted that increasing the coating porosity promotes stress relaxation and increases its thickness being limited with respect to delamination conditions in comparison with dense coatings on retention of the low defectiveness of the interface and high adhesion to the substrate. The examples of the application of high-nitrogenous steel powders in power engineering during equipment repairs by service companies and overhaul subdivisions of heat power plants are given. It is noted that the plasma spraying of diffusion-alloyed high-nitrogenous steel powders is a unique opportunity to restore nitrided steel products.

Factors that affect the fatigue strength of power transmission shafting

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.

1984-01-01

A long standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress and corrosion fatigue.

Preliminary Design Options for Meteor Burst Communications Systems Buoy Relays

DTIC Science & Technology

1986-12-01

FIELDS BRAYTON OTTO ELECTROSTATIC FIELDS SUPERCRITICAL Figure 5.1. Structure of current power source technology for ocean applications. 32 L / P 9 t ~A...As in the sulphur dioxide cell, a low weight, high surface area, carbon positive elec- trode acts as a catalyst for the reduction of the cathode...Operating Transmit Power No. (Relay/Service) Type Covert Covert Mode Duty Cycle (watts) 2.1 Trans Ocean Relay Shore/Ship No Yes Remote 20 Msg/hr 0.9

Boiling on Microconfigured Composite Surfaces Enhanced

NASA Technical Reports Server (NTRS)

Chao, David F.

2000-01-01

Boiling heat transfer is one of the key technologies for the two-phase active thermal-control system used on space platforms, as well as for the dynamic power systems aboard the International Space Station. Because it is an effective heat transfer mode, boiling is integral to many space applications, such as heat exchangers and other cooling devices. Nucleate boiling near the critical heat flux (CHF) can transport very large thermal loads with a much smaller device and much lower pumping power than for single-phase heat exchangers. However, boiling performance sharply deteriorates in a reduced-gravity environment, and operation in the CHF regime is somewhat perilous because of the risk of burnout to the device surface. New materials called microconfigured metal-graphite composites can enhance boiling. The photomicrograph shows the microconfiguration (x3000) of the copper-graphite (Cu-Gr) surface as viewed by scanning electronic microscope. The graphite fiber tips appear as plateaus with rugged surfaces embedded in the copper matrix. It has been experimentally demonstrated that this type of material manifests excellent boiling heat transfer performance characteristics and an increased CHF. Nonisothermal surfaces were less sensitive to variations of wall superheat in the CHF regime. Because of the great difference in conductivity between the copper base and the graphite fiber, the composite surfaces have a nonisothermal surface characteristic and, therefore, will have a much larger "safe" operating region in the CHF regime. In addition, the thermocapillary forces induced by the temperature differences between the fiber tips and the metal matrix play an important role in bubble detachment, and may not be adversely affected in a reduced-gravity environment. All these factors indicate that microconfigured composites may improve the reliability and economy (dominant factors in all space applications) of various thermal components found on spacecraft during future missions.

Application of ICP-OES for Evaluating Energy Extraction and Production Wastewater Discharge Impacts on Surface Waters in Western Pennsylvania

EPA Science Inventory

Oil and gas extraction and coal-fired electrical power generating stations produce wastewaters that are treated and discharged to rivers in Western Pennsylvania with public drinking water system (PDWS) intakes. Inductively coupled plasma optical emission spectroscopy (ICP-OES) w...

30 CFR 700.11 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Noncommercial use does not include the extraction of coal by one unit of an integrated company or other business or nonprofit entity which uses the coal in its own manufacturing or power plants; (2) The extraction... all coal exploration and surface coal mining and reclamation operations, except: (1) The extraction of...

30 CFR 700.11 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Noncommercial use does not include the extraction of coal by one unit of an integrated company or other business or nonprofit entity which uses the coal in its own manufacturing or power plants; (2) The extraction... all coal exploration and surface coal mining and reclamation operations, except: (1) The extraction of...

Recovering tag fiber from cottonseed using the power roll gin

USDA-ARS?s Scientific Manuscript database

In the mid-1990s, Cotton Incorporated and the USDA-ARS Cotton Production and Processing Research Unit developed a process that became known as EasiFlo™ cottonseed (Patent #5,750,466; Issued May 12, 1998). This process involves the application of gelatinized starch to the surface of fuzzy cottonseed,...

Topological characterization of antireflective and hydrophobic rough surfaces: are random process theory and fractal modeling applicable?

NASA Astrophysics Data System (ADS)

Borri, Claudia; Paggi, Marco

2015-02-01

The random process theory (RPT) has been widely applied to predict the joint probability distribution functions (PDFs) of asperity heights and curvatures of rough surfaces. A check of the predictions of RPT against the actual statistics of numerically generated random fractal surfaces and of real rough surfaces has been only partially undertaken. The present experimental and numerical study provides a deep critical comparison on this matter, providing some insight into the capabilities and limitations in applying RPT and fractal modeling to antireflective and hydrophobic rough surfaces, two important types of textured surfaces. A multi-resolution experimental campaign using a confocal profilometer with different lenses is carried out and a comprehensive software for the statistical description of rough surfaces is developed. It is found that the topology of the analyzed textured surfaces cannot be fully described according to RPT and fractal modeling. The following complexities emerge: (i) the presence of cut-offs or bi-fractality in the power-law power-spectral density (PSD) functions; (ii) a more pronounced shift of the PSD by changing resolution as compared to what was expected from fractal modeling; (iii) inaccuracy of the RPT in describing the joint PDFs of asperity heights and curvatures of textured surfaces; (iv) lack of resolution-invariance of joint PDFs of textured surfaces in case of special surface treatments, not accounted for by fractal modeling.

Wavelength specific excitation of gold nanoparticle thin-films

NASA Astrophysics Data System (ADS)

Lucas, Thomas M.; James, Kurtis T.; Beharic, Jasmin; Moiseeva, Evgeniya V.; Keynton, Robert S.; O'Toole, Martin G.; Harnett, Cindy K.

2014-01-01

Advances in microelectromechanical systems (MEMS) continue to empower researchers with the ability to sense and actuate at the micro scale. Thermally driven MEMS components are often used for their rapid response and ability to apply relatively high forces. However, thermally driven MEMS often have high power consumption and require physical wiring to the device. This work demonstrates a basis for designing light-powered MEMS with a wavelength specific response. This is accomplished by patterning surface regions with a thin film containing gold nanoparticles that are tuned to have an absorption peak at a particular wavelength. The heating behavior of these patterned surfaces is selected by the wavelength of laser directed at the sample. This method also eliminates the need for wires to power a device. The results demonstrate that gold nanoparticle films are effective wavelength-selective absorbers. This "hybrid" of infrared absorbent gold nanoparticles and MEMS fabrication technology has potential applications in light-actuated switches and other mechanical structures that must bend at specific regions. Deposition methods and surface chemistry will be integrated with three-dimensional MEMS structures in the next phase of this work. The long-term goal of this project is a system of light-powered microactuators for exploring cellular responses to mechanical stimuli, increasing our fundamental understanding of tissue response to everyday mechanical stresses at the molecular level.

Experimental Evaluation of a Water Shield for a Surface Power Reactor

NASA Technical Reports Server (NTRS)

Pearson, J. Boise; Reid, Robert S.

2006-01-01

As part of the Vision for Space Exploration the end of the next decade will bring man back to the surface of the moon. One of the most critical issues for the establishment of human presence on the moon will be the availability of compact power sources. The establishment of man on the moon will require power from greater than 10's of kWt's in follow on years. Nuclear reactors are extremely we11 suited to meet the needs for power generation on the lunar or Martian surface. reactor system. Several competing concepts exist for lightweight, safe, robust shielding systems such as a water shield, lithium hydride (LiH), Boron Carbide, and others. Water offers several potential advantages, including reduced cost, reduced technical risk, and reduced mass. Water has not typically been considered for space reactor applications because of the need for gravity to remove the potential for radiation streaming paths. The water shield concept relies on predictions of passive circulation of the shield water by natural convection to adequately cool the shield. This prediction needs to be experimentally evaluated, especially for shields with complex geometries. MSFC has developed the experience and fac necessary to do this evaluation in the Early Flight Fission - Test Facility (EFF-TF).

Lithium Iron Phosphate Cell Performance Evaluations for Lunar Extravehicular Activities

NASA Technical Reports Server (NTRS)

Reid, Concha

2007-01-01

Lithium-ion battery cells are being evaluated for their ability to provide primary power and energy storage for NASA s future Exploration missions. These missions include the Orion Crew Exploration Vehicle, the Ares Crew Launch Vehicle Upper Stage, Extravehicular Activities (EVA, the advanced space suit), the Lunar Surface Ascent Module (LSAM), and the Lunar Precursor and Robotic Program (LPRP), among others. Each of these missions will have different battery requirements. Some missions may require high specific energy and high energy density, while others may require high specific power, wide operating temperature ranges, or a combination of several of these attributes. EVA is one type of mission that presents particular challenges for today s existing power sources. The Portable Life Support System (PLSS) for the advanced Lunar surface suit will be carried on an astronaut s back during eight hour long sorties, requiring a lightweight power source. Lunar sorties are also expected to occur during varying environmental conditions, requiring a power source that can operate over a wide range of temperatures. Concepts for Lunar EVAs include a primary power source for the PLSS that can recharge rapidly. A power source that can charge quickly could enable a lighter weight system that can be recharged while an astronaut is taking a short break. Preliminary results of Al23 Ml 26650 lithium iron phosphate cell performance evaluations for an advanced Lunar surface space suit application are discussed in this paper. These cells exhibit excellent recharge rate capability, however, their specific energy and energy density is lower than typical lithium-ion cell chemistries. The cells were evaluated for their ability to provide primary power in a lightweight battery system while operating at multiple temperatures.

Wireless actuation with functional acoustic surfaces

NASA Astrophysics Data System (ADS)

Qiu, T.; Palagi, S.; Mark, A. G.; Melde, K.; Adams, F.; Fischer, P.

2016-11-01

Miniaturization calls for micro-actuators that can be powered wirelessly and addressed individually. Here, we develop functional surfaces consisting of arrays of acoustically resonant micro-cavities, and we demonstrate their application as two-dimensional wireless actuators. When remotely powered by an acoustic field, the surfaces provide highly directional propulsive forces in fluids through acoustic streaming. A maximal force of ˜0.45 mN is measured on a 4 × 4 mm2 functional surface. The response of the surfaces with bubbles of different sizes is characterized experimentally. This shows a marked peak around the micro-bubbles' resonance frequency, as estimated by both an analytical model and numerical simulations. The strong frequency dependence can be exploited to address different surfaces with different acoustic frequencies, thus achieving wireless actuation with multiple degrees of freedom. The use of the functional surfaces as wireless ready-to-attach actuators is demonstrated by implementing a wireless and bidirectional miniaturized rotary motor, which is 2.6 × 2.6 × 5 mm3 in size and generates a stall torque of ˜0.5 mN.mm. The adoption of micro-structured surfaces as wireless actuators opens new possibilities in the development of miniaturized devices and tools for fluidic environments that are accessible by low intensity ultrasound fields.

Large-scale cauliflower-shaped hierarchical copper nanostructures for efficient photothermal conversion

NASA Astrophysics Data System (ADS)

Fan, Peixun; Wu, Hui; Zhong, Minlin; Zhang, Hongjun; Bai, Benfeng; Jin, Guofan

2016-07-01

Efficient solar energy harvesting and photothermal conversion have essential importance for many practical applications. Here, we present a laser-induced cauliflower-shaped hierarchical surface nanostructure on a copper surface, which exhibits extremely high omnidirectional absorption efficiency over a broad electromagnetic spectral range from the UV to the near-infrared region. The measured average hemispherical absorptance is as high as 98% within the wavelength range of 200-800 nm, and the angle dependent specular reflectance stays below 0.1% within the 0-60° incident angle. Such a structured copper surface can exhibit an apparent heating up effect under the sunlight illumination. In the experiment of evaporating water, the structured surface yields an overall photothermal conversion efficiency over 60% under an illuminating solar power density of ~1 kW m-2. The presented technology provides a cost-effective, reliable, and simple way for realizing broadband omnidirectional light absorptive metal surfaces for efficient solar energy harvesting and utilization, which is highly demanded in various light harvesting, anti-reflection, and photothermal conversion applications. Since the structure is directly formed by femtosecond laser writing, it is quite suitable for mass production and can be easily extended to a large surface area.Efficient solar energy harvesting and photothermal conversion have essential importance for many practical applications. Here, we present a laser-induced cauliflower-shaped hierarchical surface nanostructure on a copper surface, which exhibits extremely high omnidirectional absorption efficiency over a broad electromagnetic spectral range from the UV to the near-infrared region. The measured average hemispherical absorptance is as high as 98% within the wavelength range of 200-800 nm, and the angle dependent specular reflectance stays below 0.1% within the 0-60° incident angle. Such a structured copper surface can exhibit an apparent heating up effect under the sunlight illumination. In the experiment of evaporating water, the structured surface yields an overall photothermal conversion efficiency over 60% under an illuminating solar power density of ~1 kW m-2. The presented technology provides a cost-effective, reliable, and simple way for realizing broadband omnidirectional light absorptive metal surfaces for efficient solar energy harvesting and utilization, which is highly demanded in various light harvesting, anti-reflection, and photothermal conversion applications. Since the structure is directly formed by femtosecond laser writing, it is quite suitable for mass production and can be easily extended to a large surface area. Electronic supplementary information (ESI) available: XRD patterns of the fs laser structured Cu surface as produced and after the photothermal conversion test, directly measured temperature values on Cu surfaces, temperature rise on Cu surfaces at varied solar irradiation angles, comparison of the white light and IR images of the structured Cu surface with the polished Cu surface, temperature rise on the peripheral zones of the blue coating surface. See DOI: 10.1039/c6nr03662g

Application of a liquid crystal spatial light modulator to laser marking.

PubMed

Parry, Jonathan P; Beck, Rainer J; Shephard, Jonathan D; Hand, Duncan P

2011-04-20

Laser marking is demonstrated using a nanosecond (ns) pulse duration laser in combination with a liquid crystal spatial light modulator to generate two-dimensional patterns directly onto thin films and bulk metal surfaces. Previous demonstrations of laser marking with such devices have been limited to low average power lasers. Application in the ns regime enables more complex, larger scale marks to be generated with more widely available and industrially proven laser systems. The dynamic nature of the device is utilized to improve mark quality by reducing the impact of the inherently speckled intensity distribution across the generated image and reduce thermal effects in the marked surface. © 2011 Optical Society of America

Testing of a compact 10-Gbps Lasercomm system for maritime platforms

NASA Astrophysics Data System (ADS)

Juarez, Juan C.; Souza, Katherine T.; Nicholes, Dustin D.; Riggins, James L.; Tomey, Hala J.; Venkat, Radha A.

2017-08-01

Lasercomm technology continues to be of interest for many applications both in the commercial and defense sectors because of its potential to provide high bandwidth communications that are secure without the need for RF spectrum management. Over the last decade, terrestrial Lasercomm development has progressed from initial experiments in the lab through field demonstrations in airborne and maritime environments. While these demonstrations have shown high capability levels, the complexity, size, weight, and power of the systems has slowed transition into fielded systems. This paper presents field test results of a recently developed maritime Lasercomm terminal and modem architecture with a compact form factor for enabling robust, 10-Gbps class data transport over highly scintillated links as found in terrestrial applications such as air-to-air, air-to-surface, and surface-to-surface links.

Summary of the Manufacture, Testing and Model Validation of a Full-Scale Radiator for Fission Surface Power Applications

NASA Technical Reports Server (NTRS)

Ellis, David L.; Calder, James; Siamidis, John

2011-01-01

A full-scale radiator for a lunar fission surface power application was manufactured by Material innovations, Inc., for the NASA Glenn Research Center. The radiator was designed to reject 6 kWt with an inlet water temperature of 400 K and a water mass flow rate of 0.5 kg/s. While not flight hardware, the radiator incorporated many potential design features and manufacturing techniques for future flight hardware. The radiator was tested at NASA Glenn Research Center for heat rejection performance. The results showed that the radiator design was capable of rejecting over 6 kWt when operating at the design conditions. The actual performance of the radiator as a function of operational manifolds, inlet water temperature and facility sink temperature was compared to the predictive model developed by NASA Glenn Research Center. The results showed excellent agreement with the model with the actual average face sheet temperature being within 1% of the predicted value. The results will be used in the design and production of NASA s next generation fission power heat rejection systems. The NASA Glenn Research Center s Technology Demonstration Unit will be the first project to take advantage of the newly developed manufacturing techniques and analytical models.

A Comparison of Fission Power System Options for Lunar and Mars Surface Applications

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2006-01-01

This paper presents a comparison of reactor and power conversion design options for 50 kWe class lunar and Mars surface power applications with scaling from 25 to 200 kWe. Design concepts and integration approaches are provided for three reactor-converter combinations: gas-cooled Brayton, liquid-metal Stirling, and liquid-metal thermoelectric. The study examines the mass and performance of low temperature, stainless steel based reactors and higher temperature refractory reactors. The preferred system implementation approach uses crew-assisted assembly and in-situ radiation shielding via installation of the reactor in an excavated hole. As an alternative, self-deployable system concepts that use earth-delivered, on-board radiation shielding are evaluated. The analyses indicate that among the 50 kWe stainless steel reactor options, the liquid-metal Stirling system provides the lowest mass at about 5300 kg followed by the gas-cooled Brayton at 5700 kg and the liquid-metal thermoelectric at 8400 kg. The use of a higher temperature, refractory reactor favors the gas-cooled Brayton option with a system mass of about 4200 kg as compared to the Stirling and thermoelectric options at 4700 and 5600 kg, respectively. The self-deployed concepts with on-board shielding result in a factor of two system mass increase as compared to the in-situ shielded concepts.

Advanced Thin Film Solar Arrays for Space: The Terrestrial Legacy

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Hepp, Aloysius; Raffaelle, Ryne; Flood, Dennis

2001-01-01

As in the case for single crystal solar cells, the first serious thin film solar cells were developed for space applications with the promise of better power to weight ratios and lower cost. Future science, military, and commercial space missions are incredibly diverse. Military and commercial missions encompass both hundreds of kilowatt arrays to tens of watt arrays in various earth orbits. While science missions also have small to very large power needs there are additional unique requirements to provide power for near sun missions and planetary exploration including orbiters, landers, and rovers both to the inner planets and the outer planets with a major emphasis in the near term on Mars. High power missions are particularly attractive for thin film utilization. These missions are generally those involving solar electric propulsion, surface power systems to sustain an outpost or a permanent colony on the surface of the Moon or Mars, space based lasers or radar, or large Earth orbiting power stations which can serve as central utilities for other orbiting spacecraft, or potentially beaming power to the Earth itself. This paper will discuss the current state of the art of thin film solar cells and the synergy with terrestrial thin film photovoltaic evolution. It will also address some of the technology development issues required to make thin film photovoltaics a viable choice for future space power systems.

Active high-power RF switch and pulse compression system

DOEpatents

Tantawi, Sami G.; Ruth, Ronald D.; Zolotorev, Max

1998-01-01

A high-power RF switching device employs a semiconductor wafer positioned in the third port of a three-port RF device. A controllable source of directed energy, such as a suitable laser or electron beam, is aimed at the semiconductor material. When the source is turned on, the energy incident on the wafer induces an electron-hole plasma layer on the wafer, changing the wafer's dielectric constant, turning the third port into a termination for incident RF signals, and. causing all incident RF signals to be reflected from the surface of the wafer. The propagation constant of RF signals through port 3, therefore, can be changed by controlling the beam. By making the RF coupling to the third port as small as necessary, one can reduce the peak electric field on the unexcited silicon surface for any level of input power from port 1, thereby reducing risk of damaging the wafer by RF with high peak power. The switch is useful to the construction of an improved pulse compression system to boost the peak power of microwave tubes driving linear accelerators. In this application, the high-power RF switch is placed at the coupling iris between the charging waveguide and the resonant storage line of a pulse compression system. This optically controlled high power RF pulse compression system can handle hundreds of Megawatts of power at X-band.

Acoustic Sensors for Air and Surface Navigation Applications

PubMed Central

Kapoor, Rohan; Ramasamy, Subramanian; Schyndel, Ron Van

2018-01-01

This paper presents the state-of-the-art and reviews the state-of-research of acoustic sensors used for a variety of navigation and guidance applications on air and surface vehicles. In particular, this paper focuses on echolocation, which is widely utilized in nature by certain mammals (e.g., cetaceans and bats). Although acoustic sensors have been extensively adopted in various engineering applications, their use in navigation and guidance systems is yet to be fully exploited. This technology has clear potential for applications in air and surface navigation/guidance for intelligent transport systems (ITS), especially considering air and surface operations indoors and in other environments where satellite positioning is not available. Propagation of sound in the atmosphere is discussed in detail, with all potential attenuation sources taken into account. The errors introduced in echolocation measurements due to Doppler, multipath and atmospheric effects are discussed, and an uncertainty analysis method is presented for ranging error budget prediction in acoustic navigation applications. Considering the design challenges associated with monostatic and multi-static sensor implementations and looking at the performance predictions for different possible configurations, acoustic sensors show clear promises in navigation, proximity sensing, as well as obstacle detection and tracking. The integration of acoustic sensors in multi-sensor navigation systems is also considered towards the end of the paper and a low Size, Weight and Power, and Cost (SWaP-C) sensor integration architecture is presented for possible introduction in air and surface navigation systems. PMID:29414894

Scalable fabrication of carbon-based MEMS/NEMS and their applications: a review

NASA Astrophysics Data System (ADS)

Jiang, Shulan; Shi, Tielin; Zhan, Xiaobin; Xi, Shuang; Long, Hu; Gong, Bo; Li, Junjie; Cheng, Siyi; Huang, Yuanyuan; Tang, Zirong

2015-11-01

The carbon-based micro/nano electromechanical system (MEMS/NEMS) technique provides a powerful approach to large-scale manufacture of high-aspect-ratio carbon structures for wafer-level processing. The fabricated three-dimensional (3D) carbon structures have the advantages of excellent electrical and electrochemical properties, and superior biocompatibility. In order to improve their performance for applications in micro energy storage devices and microsensors, an increase in the footprint surface area is of great importance. Various approaches have been proposed for fabricating large surface area carbon-based structures, including the integration of nanostructures such as carbon nanotubes (CNTs), graphene, nanowires, nanofilms and nanowrinkles onto 3D structures, which has been proved to be effective and productive. Moreover, by etching the 3D photoresist microstructures through oxygen plasma or modifying the photoresist with specific materials which can be etched in the following pyrolysis process, micro/nano hierarchical carbon structures have been fabricated. These improved structures show excellent performance in various applications, especially in the fields of biological sensors, surface-enhanced Raman scattering, and energy storage devices such as micro-supercapacitors and fuel cells. With the rapid development of microelectronic devices, the carbon-based MEMS/NEMS technique could make more aggressive moves into microelectronics, sensors, miniaturized power systems, etc. In this review, the recent advances in the fabrication of micro/nano hierarchical carbon-based structures are introduced and the technical challenges and future outlook of the carbon-based MEMS/NEMS techniques are also analyzed.

Investigation of the thermal and optical performance of a spatial light modulator with high average power picosecond laser exposure for materials processing applications

NASA Astrophysics Data System (ADS)

Zhu, G.; Whitehead, D.; Perrie, W.; Allegre, O. J.; Olle, V.; Li, Q.; Tang, Y.; Dawson, K.; Jin, Y.; Edwardson, S. P.; Li, L.; Dearden, G.

2018-03-01

Spatial light modulators (SLMs) addressed with computer generated holograms (CGHs) can create structured light fields on demand when an incident laser beam is diffracted by a phase CGH. The power handling limitations of these devices based on a liquid crystal layer has always been of some concern. With careful engineering of chip thermal management, we report the detailed optical phase and temperature response of a liquid cooled SLM exposed to picosecond laser powers up to 〈P〉  =  220 W at 1064 nm. This information is critical for determining device performance at high laser powers. SLM chip temperature rose linearly with incident laser exposure, increasing by only 5 °C at 〈P〉  =  220 W incident power, measured with a thermal imaging camera. Thermal response time with continuous exposure was 1-2 s. The optical phase response with incident power approaches 2π radians with average power up to 〈P〉  =  130 W, hence the operational limit, while above this power, liquid crystal thickness variations limit phase response to just over π radians. Modelling of the thermal and phase response with exposure is also presented, supporting experimental observations well. These remarkable performance characteristics show that liquid crystal based SLM technology is highly robust when efficiently cooled. High speed, multi-beam plasmonic surface micro-structuring at a rate R  =  8 cm2 s-1 is achieved on polished metal surfaces at 〈P〉  =  25 W exposure while diffractive, multi-beam surface ablation with average power 〈P〉  =100 W on stainless steel is demonstrated with ablation rate of ~4 mm3 min-1. However, above 130 W, first order diffraction efficiency drops significantly in accord with the observed operational limit. Continuous exposure for a period of 45 min at a laser power of 〈P〉  =  160 W did not result in any detectable drop in diffraction efficiency, confirmed afterwards by the efficient parallel beam processing at 〈P〉  =  100 W. Hence, no permanent changes in SLM phase response characteristics have been detected. This research work will help to accelerate the use of liquid crystal spatial light modulators for both scientific and ultra high throughput laser-materials micro-structuring applications.

Lunar Applications in Reconfigurable Computing

NASA Technical Reports Server (NTRS)

Somervill, Kevin

2008-01-01

NASA s Constellation Program is developing a lunar surface outpost in which reconfigurable computing will play a significant role. Reconfigurable systems provide a number of benefits over conventional software-based implementations including performance and power efficiency, while the use of standardized reconfigurable hardware provides opportunities to reduce logistical overhead. The current vision for the lunar surface architecture includes habitation, mobility, and communications systems, each of which greatly benefit from reconfigurable hardware in applications including video processing, natural feature recognition, data formatting, IP offload processing, and embedded control systems. In deploying reprogrammable hardware, considerations similar to those of software systems must be managed. There needs to be a mechanism for discovery enabling applications to locate and utilize the available resources. Also, application interfaces are needed to provide for both configuring the resources as well as transferring data between the application and the reconfigurable hardware. Each of these topics are explored in the context of deploying reconfigurable resources as an integral aspect of the lunar exploration architecture.

A Practical Approach to Starting Fission Surface Power Development

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2006-01-01

The Prometheus Power and Propulsion Program has been reformulated to address NASA needs relative to lunar and Mars exploration. Emphasis has switched from the Jupiter Icy Moons Orbiter (JIMO) flight system development to more generalized technology development addressing Fission Surface Power (FSP) and Nuclear Thermal Propulsion (NTP). Current NASA budget priorities and the deferred mission need date for nuclear systems prohibit a fully funded reactor Flight Development Program. However, a modestly funded Advanced Technology Program can and should be conducted to reduce the risk and cost of future flight systems. A potential roadmap for FSP technology development leading to possible flight applications could include three elements: 1) Conceptual Design Studies, 2) Advanced Component Technology, and 3) Non-Nuclear System Testing. The Conceptual Design Studies would expand on recent NASA and DOE analyses while increasing the depth of study in areas of greatest uncertainty such as reactor integration and human-rated shielding. The Advanced Component Technology element would address the major technology risks through development and testing of reactor fuels, structural materials, primary loop components, shielding, power conversion, heat rejection, and power management and distribution (PMAD). The Non-Nuclear System Testing would provide a modular, technology testbed to investigate and resolve system integration issues.

Trends for Electron Beam Accelerator Applications in Industry

NASA Astrophysics Data System (ADS)

Machi, Sueo

2011-02-01

Electron beam (EB) accelerators are major pieces of industrial equipment used for many commercial radiation processing applications. The industrial use of EB accelerators has a history of more than 50 years and is still growing in terms of both its economic scale and new applications. Major applications involve the modification of polymeric materials to create value-added products, such as heat-resistant wires, heat-shrinkable sheets, automobile tires, foamed plastics, battery separators and hydrogel wound dressing. The surface curing of coatings and printing inks is a growing application for low energy electron accelerators, resulting in an environmentally friendly and an energy-saving process. Recently there has been the acceptance of the use of EB accelerators in lieu of the radioactive isotope cobalt-60 as a source for sterilizing disposable medical products. Environmental protection by the use of EB accelerators is a new and important field of application. A commercial plant for the cleaning flue gases from a coal-burning power plant is in operation in Poland, employing high power EB accelerators. In Korea, a commercial plant uses EB to clean waste water from a dye factory.

Plasmonic photothermal accumulation of particles by a microfiber decorated with gold nanostructures

NASA Astrophysics Data System (ADS)

Li, Ying; Hu, Yanjun; Wu, Xingda

2017-08-01

This paper introduces an efficient method for accumulation of particles via thermophoresis and thermal convection sustained by localized surface plasmon energy. Gold nanorods were deposited on the designated surface of a microfiber, when a 808 nm laser at an optical power of 12 mV launched into the microfiber, particles dispersed in the water were massively trapped and aggregated on the substrate. This work is envisioned to have application in photothermal cancer therapy, photothermal imaging, and targeted drug delivery.

Neutron Yield With a Pulsed Surface Flashover Deuterium Source

NASA Astrophysics Data System (ADS)

Guethlein, G.; Falabella, S.; Sampayan, S. E.; Meyer, G.; Tang, V.; Kerr, P.

2009-03-01

As a step towards developing an ultra compact D-D neutron source for various defense and homeland security applications, a compact, low average power ion source is needed. Towards that end, we are testing a high current, pulsed surface flashover ion source, with deuterated titanium as the spark contacts. Neutron yield and source lifetime data will be presented using a low voltage (<100 kV) deuterated target. With 20 ns spark drive pulses we have shown >106 neutrons/s with 1 kHz PRF

Fundamentals of fluid sealing

NASA Technical Reports Server (NTRS)

Zuk, J.

1976-01-01

The fundamentals of fluid sealing, including seal operating regimes, are discussed and the general fluid-flow equations for fluid sealing are developed. Seal performance parameters such as leakage and power loss are presented. Included in the discussion are the effects of geometry, surface deformations, rotation, and both laminar and turbulent flows. The concept of pressure balancing is presented, as are differences between liquid and gas sealing. Mechanisms of seal surface separation, fundamental friction and wear concepts applicable to seals, seal materials, and pressure-velocity (PV) criteria are discussed.

How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

PubMed Central

Leins, Martina; Gaiser, Sandra; Schulz, Andreas; Walker, Matthias; Schumacher, Uwe; Hirth, Thomas

2015-01-01

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a stable and continuous operation of the plasma is possible and the plasma torch can be used for many different applications. On one hand, the hot (3,600 K gas temperature) plasma can be used for chemical processes and on the other hand the cold afterglow (temperatures down to almost RT) can be applied for surface processes. For example chemical syntheses are interesting volume processes. Here the microwave plasma torch can be used for the decomposition of waste gases which are harmful and contribute to the global warming but are needed as etching gases in growing industry sectors like the semiconductor branch. Another application is the dissociation of CO2. Surplus electrical energy from renewable energy sources can be used to dissociate CO2 to CO and O2. The CO can be further processed to gaseous or liquid higher hydrocarbons thereby providing chemical storage of the energy, synthetic fuels or platform chemicals for the chemical industry. Applications of the afterglow of the plasma torch are the treatment of surfaces to increase the adhesion of lacquer, glue or paint, and the sterilization or decontamination of different kind of surfaces. The movie will explain how to ignite the plasma solely by microwave power without any additional igniters, e.g., electric sparks. The microwave plasma torch is based on a combination of two resonators — a coaxial one which provides the ignition of the plasma and a cylindrical one which guarantees a continuous and stable operation of the plasma after ignition. The plasma can be operated in a long microwave transparent tube for volume processes or shaped by orifices for surface treatment purposes. PMID:25938699

Reactor Testing and Qualification: Prioritized High-level Criticality Testing Needs

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. Bragg-Sitton; J. Bess; J. Werner

2011-09-01

Researchers at the Idaho National Laboratory (INL) were tasked with reviewing possible criticality testing needs to support development of the fission surface power system reactor design. Reactor physics testing can provide significant information to aid in development of technologies associated with small, fast spectrum reactors that could be applied for non-terrestrial power systems, leading to eventual system qualification. Several studies have been conducted in recent years to assess the data and analyses required to design and build a space fission power system with high confidence that the system will perform as designed [Marcille, 2004a, 2004b; Weaver, 2007; Parry et al.,more » 2008]. This report will provide a summary of previous critical tests and physics measurements that are potentially applicable to the current reactor design (both those that have been benchmarked and those not yet benchmarked), summarize recent studies of potential nuclear testing needs for space reactor development and their applicability to the current baseline fission surface power (FSP) system design, and provide an overview of a suite of tests (separate effects, sub-critical or critical) that could fill in the information database to improve the accuracy of physics modeling efforts as the FSP design is refined. Some recommendations for tasks that could be completed in the near term are also included. Specific recommendations on critical test configurations will be reserved until after the sensitivity analyses being conducted by Los Alamos National Laboratory (LANL) are completed (due August 2011).« less

A highly shape-adaptive, stretchable design based on conductive liquid for energy harvesting and self-powered biomechanical monitoring

PubMed Central

Yi, Fang; Wang, Xiaofeng; Niu, Simiao; Li, Shengming; Yin, Yajiang; Dai, Keren; Zhang, Guangjie; Lin, Long; Wen, Zhen; Guo, Hengyu; Wang, Jie; Yeh, Min-Hsin; Zi, Yunlong; Liao, Qingliang; You, Zheng; Zhang, Yue; Wang, Zhong Lin

2016-01-01

The rapid growth of deformable and stretchable electronics calls for a deformable and stretchable power source. We report a scalable approach for energy harvesters and self-powered sensors that can be highly deformable and stretchable. With conductive liquid contained in a polymer cover, a shape-adaptive triboelectric nanogenerator (saTENG) unit can effectively harvest energy in various working modes. The saTENG can maintain its performance under a strain of as large as 300%. The saTENG is so flexible that it can be conformed to any three-dimensional and curvilinear surface. We demonstrate applications of the saTENG as a wearable power source and self-powered sensor to monitor biomechanical motion. A bracelet-like saTENG worn on the wrist can light up more than 80 light-emitting diodes. Owing to the highly scalable manufacturing process, the saTENG can be easily applied for large-area energy harvesting. In addition, the saTENG can be extended to extract energy from mechanical motion using flowing water as the electrode. This approach provides a new prospect for deformable and stretchable power sources, as well as self-powered sensors, and has potential applications in various areas such as robotics, biomechanics, physiology, kinesiology, and entertainment. PMID:27386560

High power diode lasers for solid-state laser pumps

NASA Technical Reports Server (NTRS)

Linden, Kurt J.; Mcdonnell, Patrick N.

1994-01-01

The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

A highly shape-adaptive, stretchable design based on conductive liquid for energy harvesting and self-powered biomechanical monitoring.

PubMed

Yi, Fang; Wang, Xiaofeng; Niu, Simiao; Li, Shengming; Yin, Yajiang; Dai, Keren; Zhang, Guangjie; Lin, Long; Wen, Zhen; Guo, Hengyu; Wang, Jie; Yeh, Min-Hsin; Zi, Yunlong; Liao, Qingliang; You, Zheng; Zhang, Yue; Wang, Zhong Lin

2016-06-01

The rapid growth of deformable and stretchable electronics calls for a deformable and stretchable power source. We report a scalable approach for energy harvesters and self-powered sensors that can be highly deformable and stretchable. With conductive liquid contained in a polymer cover, a shape-adaptive triboelectric nanogenerator (saTENG) unit can effectively harvest energy in various working modes. The saTENG can maintain its performance under a strain of as large as 300%. The saTENG is so flexible that it can be conformed to any three-dimensional and curvilinear surface. We demonstrate applications of the saTENG as a wearable power source and self-powered sensor to monitor biomechanical motion. A bracelet-like saTENG worn on the wrist can light up more than 80 light-emitting diodes. Owing to the highly scalable manufacturing process, the saTENG can be easily applied for large-area energy harvesting. In addition, the saTENG can be extended to extract energy from mechanical motion using flowing water as the electrode. This approach provides a new prospect for deformable and stretchable power sources, as well as self-powered sensors, and has potential applications in various areas such as robotics, biomechanics, physiology, kinesiology, and entertainment.

Applications of Time-Reversal Processing for Planetary Surface Communications

NASA Technical Reports Server (NTRS)

Barton, Richard J.

2007-01-01

Due to the power constraints imposed on wireless sensor and communication networks deployed on a planetary surface during exploration, energy efficient transfer of data becomes a critical issue. In situations where groups of nodes within a network are located in relatively close proximity, cooperative communication techniques can be utilized to improve the range, data rate, power efficiency, and lifetime of the network. In particular, if the point-to-point communication channels on the network are well modeled as frequency non-selective, distributed or cooperative beamforming can employed. For frequency-selective channels, beamforming itself is not generally appropriate, but a natural generalization of it, time-reversal communication (TRC), can still be effective. Time-reversal processing has been proposed and studied previously for other applications, including acoustical imaging, electromagnetic imaging, underwater acoustic communication, and wireless communication channels. In this paper, we study both the theoretical advantages and the experimental performance of cooperative TRC for wireless communication on planetary surfaces. We give a brief introduction to TRC and present several scenarios where TRC could be profitably employed during planetary exploration. We also present simulation results illustrating the performance of cooperative TRC employed in a complex multipath environment and discuss the optimality of cooperative TRC for data aggregation in wireless sensor networks

Nuclear Systems Kilopower Overview

NASA Technical Reports Server (NTRS)

Palac, Don; Gibson, Marc; Mason, Lee; Houts, Michael; McClure, Patrick; Robinson, Ross

2016-01-01

The Nuclear Systems Kilopower Project was initiated by NASAs Space Technology Mission Directorate Game Changing Development Program in fiscal year 2015 to demonstrate subsystem-level technology readiness of small space fission power in a relevant environment (Technology Readiness Level 5) for space science and human exploration power needs. The Nuclear Systems Kilopower Project consists of two elements. The primary element is the Kilopower Prototype Test, also called the Kilopower Reactor Using Stirling Technology(KRUSTY) Test. This element consists of the development and testing of a fission ground technology demonstrator of a 1 kWe fission power system. A 1 kWe system matches requirements for some robotic precursor exploration systems and future potential deep space science missions, and also allows a nuclear ground technology demonstration in existing nuclear test facilities at low cost. The second element, the Mars Kilopower Scalability Study, consists of the analysis and design of a scaled-up version of the 1 kWe reference concept to 10 kWe for Mars surface power projected requirements, and validation of the applicability of the KRUSTY experiment to key technology challenges for a 10 kWe system. If successful, these two elements will lead to initiation of planning for a technology demonstration of a 10 kWe fission power capability for Mars surface outpost power.

Pratt & Whitney ESCORT derivative for mars surface power

NASA Astrophysics Data System (ADS)

Feller, Gerald J.; Joyner, Russell

1999-01-01

The purpose of this paper is to address the applicability of a common reactor system design from the Pratt & Whitney ESCORT nuclear thermal rocket engine concept to support current NASA mars surface-based power requirements. The ESCORT is a bimodal engine capable of supporting a wide range of propulsive thermal and vehicle electrical power requirements. The ESCORT engine is powered by a fast-spectrum beryllium-reflected CERMET-fueled nuclear reactor. In addition to an expander cycle propulsive mode, the ESCORT is capable of operating in an electrical power mode. In this mode, the reactor is used to heat a mixture of helium and xenon to drive a closed-loop Brayton cycle in order to generate electrical energy. Recent Design Reference Mission requirements (DRM) from NASA Johnson Space Center and NASA Lewis Research Center studies in 1997 and 1998 have detailed upgraded requirements for potential mars transfer missions. The current NASA DRM requires a nuclear thermal propulsion system capable of delivering total mission requirements of 200170 N (45000 lbf) thrust and 50 kWe of spacecraft electrical power. Additionally, these requirements detailed a surface power system capable of providing approximately 160 kW of electrical energy over an approximate 10 year period within a given weight and volume envelope. Current NASA studies use a SP-100 reactor (0.8 MT) and a NERVA derivative (1.6 MT) as baseline systems. A mobile power cart of approximate dimensions 1.7 m×4.5 m×4.4 m has been conceptualized to transport the reactor power system on the Mars Surface. The 63.25 cm diameter and 80.25 cm height of the ESCORT and its 1.3 MT of weight fit well within the current weight and volume target range of the NASA DRM requirements. The modifications required to the ESCORT reactor system to support this upgraded electrical power requirements along with operation in the Martian atmospheric conditions are addressed in this paper. Sufficient excess reactivity and burnup capability were designed into the ESCORT reactor system to support these upgraded requirements. Only slight modifications to reactor hardware were required to address any environmental considerations. These modifications involved sealing any refractory metal alloy components from the CO2 in the Martian Atmosphere. Also, the Brayton cycle Power Conversion Unit (PCU) hardware was modified to support the upgraded requirements. This paper discusses the design analysis performed and provides information on the final common reactor concept to be used on the Mars surface to support manned missions.

High peak power solid-state laser for micromachining of hard materials

NASA Astrophysics Data System (ADS)

Herbst, Ludolf; Quitter, John P.; Ray, Gregory M.; Kuntze, Thomas; Wiessner, Alexander O.; Govorkov, Sergei V.; Heglin, Mike

2003-06-01

Laser micromachining has become a key enabling technology in the ever-continuing trend of miniaturization in microelectronics, micro-optics, and micromechanics. New applications have become commercially viable due to the emergence of innovative laser sources, such as diode pumped solid-state lasers (DPSSL), and the progress in processing technology. Examples of industrial applications are laser-drilled micro-injection nozzles for highly efficient automobile engines, or manufacturing of complex spinnerets for production of synthetic fibers. The unique advantages of laser-based techniques stem from their ability to produce high aspect ratio holes, while yielding low heat affected zones with exceptional surface quality, roundness and taper tolerances. Additionally, the ability to drill blind holes and slots in very hard materials such as diamond, silicon, sapphire, ceramics and steel is of great interest for many applications in microelectronics, semiconductor and automotive industry. This kind of high quality, high aspect ratio micromachining requires high peak power and short pulse durations.

Flexible holey graphene paper electrodes with enhanced rate capability for energy storage applications.

PubMed

Zhao, Xin; Hayner, Cary M; Kung, Mayfair C; Kung, Harold H

2011-11-22

The unique combination of high surface area, high electrical conductivity and robust mechanical integrity has attracted great interest in the use of graphene sheets for future electronics applications. Their potential applications for high-power energy storage devices, however, are restricted by the accessible volume, which may be only a fraction of the physical volume, a consequence of the compact geometry of the stack and the ion mobility. Here we demonstrated that remarkably enhanced power delivery can be realized in graphene papers for the use in Li-ion batteries by controlled generation of in-plane porosity via a mechanical cavitation-chemical oxidation approach. These flexible, holey graphene papers, created via facile microscopic engineering, possess abundant ion binding sites, enhanced ion diffusion kinetics, and excellent high-rate lithium-ion storage capabilities, and are suitable for high-performance energy storage devices. © 2011 American Chemical Society

High power laser energy distribution patterns, apparatus and methods for creating wells

DOEpatents

Faircloth, Brian O.; Zediker, Mark S.; Rinzler, Charles C.; Koblick, Yeshaya; Moxley, Joel F.

2016-03-15

There is provided a system, apparatus and methods for providing a laser beam to borehole surface in a predetermined and energy deposition profile. The predetermined energy deposition profiles may be uniform or tailored to specific downhole applications. Optic assemblies for obtaining these predetermined energy deposition profiles are further provided.

Thermal Interface Comparisons Under Flight Like Conditions

NASA Technical Reports Server (NTRS)

Rodriquez-Ruiz, Juan

2008-01-01

Thermal interface materials are used in bolted interfaces to promote good thermal conduction between the two. The mounting surface can include panels, heat pipes, electronics boxes, etc.. . On Lunar Reconnaissance Orbiter (LRO) project the results are directly applicable: a) Several high power avionics boxes b) Several interfaces from RWA to radiator through heat pipe network

78 FR 37281 - Revisions to Environmental Review for Renewal of Nuclear Power Plant Operating Licenses

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-20

... protection regulations by updating the Commission's 1996 findings on the environmental effect of renewing the... effects will be adequately managed. The applicant must demonstrate that the effects of aging will be...; effects of dredging on surface water quality; groundwater use and quality; exposure of terrestrial...

Environmentally responsive optical microstructured hybrid actuator assemblies and applications thereof

DOEpatents

Aizenberg, Joanna; Aizenberg, Michael; Kim, Philseok

2016-01-05

Microstructured hybrid actuator assemblies in which microactuators carrying designed surface properties to be revealed upon actuation are embedded in a layer of responsive materials. The microactuators in a microactuator array reversibly change their configuration in response to a change in the environment without requiring an external power source to switch their optical properties.

Multifunctional Hybrid Multilayer Gate Dielectrics with Tunable Surface Energy for Ultralow-Power Organic and Amorphous Oxide Thin-Film Transistors.

PubMed

Byun, Hye-Ran; You, Eun-Ah; Ha, Young-Geun

2017-03-01

For large-area, printable, and flexible electronic applications using advanced semiconductors, novel dielectric materials with excellent capacitance, insulating property, thermal stability, and mechanical flexibility need to be developed to achieve high-performance, ultralow-voltage operation of thin-film transistors (TFTs). In this work, we first report on the facile fabrication of multifunctional hybrid multilayer gate dielectrics with tunable surface energy via a low-temperature solution-process to produce ultralow-voltage organic and amorphous oxide TFTs. The hybrid multilayer dielectric materials are constructed by iteratively stacking bifunctional phosphonic acid-based self-assembled monolayers combined with ultrathin high-k oxide layers. The nanoscopic thickness-controllable hybrid dielectrics exhibit the superior capacitance (up to 970 nF/cm 2 ), insulating property (leakage current densities <10 -7 A/cm 2 ), and thermal stability (up to 300 °C) as well as smooth surfaces (root-mean-square roughness <0.35 nm). In addition, the surface energy of the hybrid multilayer dielectrics are easily changed by switching between mono- and bifunctional phosphonic acid-based self-assembled monolayers for compatible fabrication with both organic and amorphous oxide semiconductors. Consequently, the hybrid multilayer dielectrics integrated into TFTs reveal their excellent dielectric functions to achieve high-performance, ultralow-voltage operation (< ± 2 V) for both organic and amorphous oxide TFTs. Because of the easily tunable surface energy, the multifunctional hybrid multilayer dielectrics can also be adapted for various organic and inorganic semiconductors, and metal gates in other device configurations, thus allowing diverse advanced electronic applications including ultralow-power and large-area electronic devices.

Underwater cleaning techniqued used for removal of zebra mussels at the FitzPatrick Nuclear Power Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobbs, B.; Kahabka, J.

1995-06-01

This paper discusses the use of a mechanical brush cleaning technology recently used to remove biofouling from the Circulating Water (CW) System at New York Power Authority`s James A. FitzPatrick Nuclear Power Plant. The FitzPatrick plant had previously used chemical molluscicide to treat zebra mussels in the CW system. Full system treatment was performed in 1992 with limited forebay/screenwell treatment in 1993. The New York Power Authority (NYPA) decided to conduct a mechanical cleaning of the intake system in 1994. Specific project objectives included: (1) Achieve a level of surface cleaniness greater than 98%; (2) Remove 100% of debris, bothmore » existing sediment and debris generated as a result of cleaning; (3) Inspect all surfaces and components, identifying any problem areas; (4) Complete the task in a time frame within the 1994-95 refueling outage schedule window, and; (5) Determine if underwater mechanical cleaning is a cost-effective zebra mussel control method suitable for future application at FitzPatrick. A pre-cleaning inspection, including underwater video photography, was conducted of each area. Cleaning was accomplished using diver-controlled, multi-brush equipment included the electro-hydraulic powered Submersible Cleaning and Maintenance Platform (SCAMP), and several designs of hand-held machines. The brushes swept all zebra mussels off surfaces, restoring concrete and metal substrates to their original condition. Sensitive areas including pump housings, standpipes, sensor piping and chlorine injection tubing, were cleaned without degradation. Submersible vortex vacuum pumps were used to remove debris from the cavity. More than 46,000 ft{sup 2} of surface area was cleaned and over 460 cubic yards of dewatered debris were removed. As each area was completed, a post-clean inspection with photos and video was performed.« less

A homogeneous focusing system for diode lasers and its applications in metal surface modification

NASA Astrophysics Data System (ADS)

Wang, Fei; Zhong, Lijing; Tang, Xiahui; Xu, Chengwen; Wan, Chenhao

2018-06-01

High power diode lasers are applied in many different areas, including surface modification, welding and cutting. It is an important technical trend in laser processing of metals in the future. This paper aims to analyze the impact of the shape and homogeneity of the focal spot of the diode laser on surface modification. A focusing system using the triplet lenses for a direct output diode laser which can be used to eliminate coma aberrations is studied. A rectangular stripe with an aspect ratio from 8:1 to 25:1 is obtained, in which the power is homogeneously distributed along the fast axis, the power is 1117.6 W and the peak power intensity is 1.1587 × 106 W/cm2. This paper also presents a homogeneous focusing system by use of a Fresnel lens, in which the incident beam size is 40 × 40 mm2, the focal length is 380 mm, and the dimension of the obtained focal spot is 2 × 10 mm2. When the divergence angle of the incident light is in the range of 12.5-20 mrad and the pitch is 1 mm, the obtained homogeneity in the focal spot is the optimum (about 95.22%). Experimental results show that the measured focal spot size is 2.04 × 10.39 mm2. This research presents a novel design of homogeneous focusing systems for high power diode lasers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datskos, Panos G; Polyzos, Georgios; Clemons, Art

The purpose of this project was to develop surface treatments which will inhibit the formation of ice on turbine blades and propellers. ORNL worked with Piedmont Propulsion Systems, LLC and First Aviation Services Inc. to demonstrate a new surface treatment for two primary markets, aviation and wind turbines, as well as secondary markets such as power lines, bridges, boats, roofs and antennas among others. Exploring alternative surface treatments for wind turbines will provide anti-icing properties and erosion/abrasion prevention properties similar to those for aviation applications. A series of superhydrophobic coating materials was synthesized and successfully applied on anti-ice tape materialsmore » that could be used in a wide range of wind turbine and aviation applications to prevent ice accumulation. The coatings developed in this project were based on superhydrophobic particles of different geometries and sizes that were homogeneously dispersed in polymeric binders. The superhydrophobic features of the coatings are volumetric and their abrasion resistance was evaluated. Future research will involve the demonstration of anti-icing properties of the surface treatment developed in this project.« less

Surface Modifications of Materials by Electrochemical Methods to Improve the Properties for Industrial and Medical Applications

NASA Astrophysics Data System (ADS)

Benea, Lidia

2018-06-01

There are two applied electrochemical methods in our group in order to obtain advanced functional surfaces on materials: (i) direct electrochemical synthesis by electro-codeposition process and (ii) anodization of materials to form nanoporous oxide layers followed by electrodeposition of hydroxyapatite or other bioactive molecules and compounds into porous film. Electrodeposition is a process of low energy consumption, and therefore very convenient for the surface modification of various types of materials. Electrodeposition is a powerful method compared with other methods, which led her to be adopted and spread rapidly in nanotechnology to obtain nanostructured layers and films. Nanoporous thin oxide layers on titanum alloys as support for hydroxyapatite or other biomolecules electrodeposition in view of biomedical applications could be obtained by electrochemical methods. For surface modification of titanium or titanium alloys to improve the biocompatibility or osseointegration, the two steps must be fulfilled; the first is controlled growth of oxide layer followed by second being biomolecule electrodeposition into nanoporous formed titanium oxide layer.

Evaluation of algorithms for point cloud surface reconstruction through the analysis of shape parameters

NASA Astrophysics Data System (ADS)

Cao, Lu; Verbeek, Fons J.

2012-03-01

In computer graphics and visualization, reconstruction of a 3D surface from a point cloud is an important research area. As the surface contains information that can be measured, i.e. expressed in features, the application of surface reconstruction can be potentially important for application in bio-imaging. Opportunities in this application area are the motivation for this study. In the past decade, a number of algorithms for surface reconstruction have been proposed. Generally speaking, these methods can be separated into two categories: i.e., explicit representation and implicit approximation. Most of the aforementioned methods are firmly based in theory; however, so far, no analytical evaluation between these methods has been presented. The straightforward way of evaluation has been by convincing through visual inspection. Through evaluation we search for a method that can precisely preserve the surface characteristics and that is robust in the presence of noise. The outcome will be used to improve reliability in surface reconstruction of biological models. We, therefore, use an analytical approach by selecting features as surface descriptors and measure these features in varying conditions. We selected surface distance, surface area and surface curvature as three major features to compare quality of the surface created by the different algorithms. Our starting point has been ground truth values obtained from analytical shapes such as the sphere and the ellipsoid. In this paper we present four classical surface reconstruction methods from the two categories mentioned above, i.e. the Power Crust, the Robust Cocone, the Fourier-based method and the Poisson reconstruction method. The results obtained from our experiments indicate that Poisson reconstruction method performs the best in the presence of noise.

Stability assessment of the chemical composition of the treated mining water used to replenish the cooling circuit in Jaworzno III Power Plant - Power Plant II

NASA Astrophysics Data System (ADS)

Karpiński, Marcin; Kmiecik, Ewa

2017-11-01

In Poland, electricity is still produced mainly in conventional power plants where fuel and water are materials necessary to generate the electricity. Even in modern power plants operating according to the principles of the sustainable development, this involves a high intake of water and considerable production of wastewater. This, in turn, necessi-tates the application of some technological solutions aimed at limiting the negative impact on the environment. The Jaworzno III Power Plant - Power Plant II is located in Jaworzno, Silesian Province, Poland. In order to minimise the negative impact on the surface water, the plant replenishes the cooling circuit with the mining water obtained from the closed-down Jan Kanty mine. The paper presents a stability assessment of the chemical composition of the treated mining water used to replenish the cooling circuit based on the data from 2007-2017.

Conductive aluminum line formation on aluminum nitride surface by infrared nanosecond laser

NASA Astrophysics Data System (ADS)

Kozioł, Paweł E.; Antończak, Arkadiusz J.; Szymczyk, Patrycja; Stępak, Bogusz; Abramski, Krzysztof M.

2013-12-01

In this paper the fabrication of conductive aluminum paths on AlN ceramic's surface due to the interaction of laser radiation Nd:YAG (1.064 μm) is presented. The metallization process produces an appropriate power value on the ceramics surface to ensure the correct temperature (2200 °C) for which aluminum and nitrogen bonds are broken. Studies have been undertaken on creating low-ohmic structures depending on the parameters such as radiation power, scanning speed, the coverage of subsequent pulses and the environmental impact of the process (air, nitrogen, argon). Furthermore, with regards to the application of this method, it was significant to determine the thickness of the functional layer. A structure of the resistivity of ρ = 0.64 × 10-6 Ω m and aluminum layer thickness of 10 μm was achieved for the process carried out on the inert gas, argon. In addition, a quantitative analysis of nitrogen and aluminum for laser-treated structures was conducted. The performed tests confirmed that the highest amount of aluminum was produced on the surface treated by laser radiation in the environment of the process gas, argon.

Thermoelectric Power Generation System for Future Hybrid Vehicles Using Hot Exhaust Gas

NASA Astrophysics Data System (ADS)

Kim, Sun-Kook; Won, Byeong-Cheol; Rhi, Seok-Ho; Kim, Shi-Ho; Yoo, Jeong-Ho; Jang, Ju-Chan

2011-05-01

The present experimental and computational study investigates a new exhaust gas waste heat recovery system for hybrid vehicles, using a thermoelectric module (TEM) and heat pipes to produce electric power. It proposes a new thermoelectric generation (TEG) system, working with heat pipes to produce electricity from a limited hot surface area. The current TEG system is directly connected to the exhaust pipe, and the amount of electricity generated by the TEMs is directly proportional to their heated area. Current exhaust pipes fail to offer a sufficiently large hot surface area for the high-efficiency waste heat recovery required. To overcome this, a new TEG system has been designed to have an enlarged hot surface area by the addition of ten heat pipes, which act as highly efficient heat transfer devices and can transmit the heat to many TEMs. As designed, this new waste heat recovery system produces a maximum 350 W when the hot exhaust gas heats the evaporator surface of the heat pipe to 170°C; this promises great possibilities for application of this technology in future energy-efficient hybrid vehicles.

Plasmonics analysis of nanostructures for bioapplications

NASA Astrophysics Data System (ADS)

Xie, Qian

Plasmonics, the science and technology of the plasmons, is a rapidly growing field with substantial broader impact in numerous different fields, especially for bio-applications such as bio-sensing, bio-photonics and photothermal therapy. Resonance effects associated with plasmatic behavior i.e. surface Plasmon resonance (SPR) and localize surface Plasmon resonance (LSPR), are of particular interest because of their strong sensitivity to the local environment. In this thesis, plasmonic resonance effects are discussed from the basic theory to applications, especially the application in photothermal therapy, and grating bio-sensing. This thesis focuses on modeling different metallic nanostructures, i.e. nanospheres, nanorods, core-shell nanoparticles, nanotori and hexagonal closed packed nanosphere structures, to determine their LSPR wavelengths for use in various applications. Experiments regarding photothermal therapy using gold nanorods are described and a comparison is presented with results obtained from simulations. Lastly, experiments of grating-based plasmon-enhanced bio-sensing are also discussed. In chapter one, the physics of plasmonics is reviewed, including surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR). In the section on surface plasmon resonance, the physics behind the phenomenon is discussed, and also, the detection methods and applications in bio-sensing are described. In the section on localized surface plasmon resonance (LSPR), the phenomenon is described with respect to sub wavelength metallic nanoparticles. In chapter two, specific plasmonic-based bio-applications are discussed including plasmonic and magneto-plasmonic enhanced photothermal therapy and grating-based SPR bio-sening. In chapter three, which is the most important part in the thesis, optical modeling of different gold nanostructures is presented. The modeling tools used in this thesis are Comsol and custom developed Matlab programs. In Comsol, the geometries of different metallic nanostructures are drawn and simulated using finite element-based computational electromagnetics. The power absorption of the nanostructures is plotted as a function of wavelength to identify the LSPR wavelength, i.e. the wavelength of peak absorption. In Matlab, Mie scattering theory is programmed in terms of semi-analytical mathematical equations, which predict the power absorption for specific plasmonic geometries, i.e. nanospheres, nanorods and core-shell particles. These predictions, which are much faster than the Comsol analysis, are validated using corresponding numerical simulations. In chapter four, experiments involving novel magneto-plasmonic Nano platforms are described, and experimental data is presented to illustrate the use of the modeling in analyzing these particles. Simulations are performed to determine the influence on the laser absorption of magnetic nanospheres in proximity to metallic nanorods. These results are compared with experimental data. In the last chapter, experiments using a grating-based SPR sensor are described, and modeling results are also presented. In summary, this thesis discusses the physics of plasmonics, electromagnetic analysis for predicting the absorption spectra of metallic nanoparticles and bio-applications that utilize these effects.

Bioanalytical applications of SERS (surface-enhanced Raman spectroscopy).

PubMed

Hudson, Stephen D; Chumanov, George

2009-06-01

Surface-enhanced Raman scattering (SERS) is a powerful technique for analyzing biological samples as it can rapidly and nondestructively provide chemical and, in some cases, structural information about molecules in aqueous environments. In the Raman scattering process, both visible and near-infrared (NIR) wavelengths of light can be used to induce polarization of Raman-active molecules, leading to inelastic light scattering that yields specific molecular vibrational information. The development of surface enhancement has enabled Raman scattering to be an effective tool for qualitative as well as quantitative measurements with high sensitivity and specificity. Recent advances have led to many novel applications of SERS for biological analyses, resulting in new insights for biochemistry and molecular biology, the detection of biological warfare agents, and medical diagnostics for cancer, diabetes, and other diseases. This trend article highlights many of these recent investigations and provides a brief outlook in order to assess possible future directions of SERS as a bioanalytical tool.

Analysis of surface structures of chemically peculiar stars with modern and future interferometers

NASA Astrophysics Data System (ADS)

Shulyak, D.; Perraut, K.; Paladini, Claudia; Li Causi, G.; Sacuto, Stephane; Kochukhov, O.

2014-07-01

Interferometry is a very powerful observational technique known in astronomy for many decades. Its application to main-sequence stars, however, is still limited to only brightest objects. In this work we aim to explore the application of interferometry to a special class of main-sequence stars known as chemically peculiar (CP) stars. These stars demonstrate surface chemical abundance inhomogeneities (spots) that usually cover a considerable part of the stellar surface and induce a pronounced spectral and photometric variability. Interferometry thus has a potential to naturally resolve such spots in single stars, providing unique complementary information about spots sizes and contrasts. By means of numerical experiments we derive the actual interferometric requirements essential for the CP stars research that can be addressed in future instrument development. The first comparison between theoretical predictions and already available observations will also be discussed.

Modeling of SAW Delay Lines

NASA Technical Reports Server (NTRS)

Wilson, William C.; Atkinson, Gary M.

2007-01-01

Integrated Vehicle Health Monitoring (IVHM) of aerospace vehicles requires rugged sensors having reduced volume, mass, and power that can be used to measure a variety of phenomena. Wireless systems are preferred when retro-fitting sensors onto existing vehicles. Surface Acoustic Wave (SAW) devices are capable of sensing: temperature, pressure, strain, chemical species, mass loading, acceleration, and shear stress. SAW technology is low cost, rugged, lightweight, and extremely low power. To aid in the development of SAW sensors for IVHM applications, a first order model of a SAW Delay line has been created.

Factors that affect the fatigue strength of power transmission shafting and their impact on design

NASA Technical Reports Server (NTRS)

Leowenthal, S. H.

1986-01-01

A long standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress and corrosion fatigue.

A thermophone on porous polymeric substrate

NASA Astrophysics Data System (ADS)

Chitnis, G.; Kim, A.; Song, S. H.; Jessop, A. M.; Bolton, J. S.; Ziaie, B.

2012-07-01

In this Letter, we present a simple, low-temperature method for fabricating a wide-band (>80 kHz) thermo-acoustic sound generator on a porous polymeric substrate. We were able to achieve up to 80 dB of sound pressure level with an input power of 0.511 W. No significant surface temperature increase was observed in the device even at an input power level of 2.5 W. Wide-band ultrasonic performance, simplicity of structure, and scalability of the fabrication process make this device suitable for many ranging and imaging applications.

Theoretical Heterogeneous Catalysis: Scaling Relationships and Computational Catalyst Design.

PubMed

Greeley, Jeffrey

2016-06-07

Scaling relationships are theoretical constructs that relate the binding energies of a wide variety of catalytic intermediates across a range of catalyst surfaces. Such relationships are ultimately derived from bond order conservation principles that were first introduced several decades ago. Through the growing power of computational surface science and catalysis, these concepts and their applications have recently begun to have a major impact in studies of catalytic reactivity and heterogeneous catalyst design. In this review, the detailed theory behind scaling relationships is discussed, and the existence of these relationships for catalytic materials ranging from pure metal to oxide surfaces, for numerous classes of molecules, and for a variety of catalytic surface structures is described. The use of the relationships to understand and elucidate reactivity trends across wide classes of catalytic surfaces and, in some cases, to predict optimal catalysts for certain chemical reactions, is explored. Finally, the observation that, in spite of the tremendous power of scaling relationships, their very existence places limits on the maximum rates that may be obtained for the catalyst classes in question is discussed, and promising strategies are explored to overcome these limitations to usher in a new era of theory-driven catalyst design.

Machining Data Handbook. 3rd Edition. Volume 2

DTIC Science & Technology

1980-01-01

17.2 The power required in machining can be determined by vided in figures 17.2-3 through 17.2-10 for deternining the several different methods as...patterns and require not caused problems. and the. e have been reports of im- different methods of checking. proved die life in speial applications...microinches Ra 11.25 to 5.0 Am application of this method the surface is subjected to melt- RaJ) and wide differences in recast layer thicknesses ing

Preparation Methods of Metal Organic Frameworks and Their Capture of CO2

NASA Astrophysics Data System (ADS)

Zhang, Linjian; Liand, Fangqin; Luo, Liangfei

2018-01-01

The increasingly serious greenhouse effect makes people pay more attention to the capture and storage technology of CO2. Metal organic frameworks (MOFs) have the advantages of high specific surface area, porous structure and controllable structure, and become the research focus of CO2 emission reduction technology in recent years. In this paper, the characteristics, preparation methods and application of MOFs in the field of CO2 adsorption and separation are discussed, especially the application of flue gas environment in power plants.

Mechanical stress-controlled tunable active frequency-selective surface

NASA Astrophysics Data System (ADS)

Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

2017-01-01

This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

Application of acoustic surface wave technology to shuttle radar

NASA Technical Reports Server (NTRS)

1975-01-01

The application of surface acoustic wave (SAW) signal processing devices in the space shuttle was explored. In order to demonstrate the functions which a SAW device might perform, a breadboard pulse compression filter (PCF) module was assembled. The PCF permits a pulse radar to operate with a large duty cycle and low peak power, a regime favorable to the use of solid state RF sources. The transducer design, strong coupling compensation, circuit model analysis, fabrication limitations, and performance evaluation of a PCF are described. The nominal value of the compression ratio is 100:1 with 10-MHz bandwidth centered at 60 MHz and 10-microsecond dispersive delay. The PCF incorporates dispersive interdigital transducers and a piezoelectric lithium niobate substrate.

Radar polarimetry - Analysis tools and applications

NASA Technical Reports Server (NTRS)

Evans, Diane L.; Farr, Tom G.; Van Zyl, Jakob J.; Zebker, Howard A.

1988-01-01

The authors have developed several techniques to analyze polarimetric radar data from the NASA/JPL airborne SAR for earth science applications. The techniques determine the heterogeneity of scatterers with subregions, optimize the return power from these areas, and identify probable scattering mechanisms for each pixel in a radar image. These techniques are applied to the discrimination and characterization of geologic surfaces and vegetation cover, and it is found that their utility varies depending on the terrain type. It is concluded that there are several classes of problems amenable to single-frequency polarimetric data analysis, including characterization of surface roughness and vegetation structure, and estimation of vegetation density. Polarimetric radar remote sensing can thus be a useful tool for monitoring a set of earth science parameters.

On-chip remote charger model using plasmonic island circuit

NASA Astrophysics Data System (ADS)

Ali, J.; Youplao, P.; Pornsuwancharoen, N.; Aziz, M. S.; Chiangga, S.; Amiri, I. S.; Punthawanunt, S.; Singh, G.; Yupapin, P.

2018-06-01

We propose the remote charger model using the light fidelity (LiFi) transmission and integrate microring resonator circuit. It consists of the stacked layers of silicon-graphene-gold materials known as a plasmonic island placed at the center of the modified add-drop filter. The input light power from the remote LiFi can enter into the island via a silicon waveguide. The optimized input power is obtained by the coupled micro-lens on the silicon surface. The induced electron mobility generated in the gold layer by the interfacing layer between silicon-graphene. This is the reversed interaction of the whispering gallery mode light power of the microring system, in which the generated power is fed back into the microring circuit. The electron mobility is the required output and obtained at the device ports and characterized for the remote current source applications. The obtained calculation results have shown that the output current of ∼2.5 × 10-11 AW-1, with the gold height of 1.0 μm and the input power of 5.0 W is obtained at the output port, which is shown the potential application for a short range free pace remote charger.

Corrosion study on high power feeding of telecomunication copper cable in 5 wt.% CaSO4.2H2O solution

NASA Astrophysics Data System (ADS)

Shamsudin, Shaiful Rizam; Hashim, Nabihah; Ibrahim, Mohd Saiful Bahri; Rahman, Muhammad Sayuzi Abdul; Idrus, Muhammad Amin; Hassan, Mohd Rezadzudin; Abdullah, Wan Razli Wan

2016-07-01

The studies were carried out to find out the best powering scheme over the copper telephone line. It was expected that the application of the higher power feeding could increase the data transfer and capable of providing the customer's satisfaction. To realize the application of higher remote power feeding, the potential of corrosion problem on Cu cables was studied. The natural corrosion behaviour of copper cable in the 0.5% CaSO4.2H2O solution was studied in term of open circuit potential for 30 days. The corrosion behaviour of higher power feeding was studied by the immersion and the planned interval test to determine the corrosion rate as well as the effect of voltage magnitudes and the current scheme i.e. positive direct (DC+) and alternating current (AC) at about 0.40 ± 0.01 mA/ cm2 current density. In the immersion test, both DC+ and AC scheme showed the increasing of feeding voltage magnitude has increased the corrosion rate of Cu samples starting from 60 to 100 volts. It was then reduced at about 100 - 120 volts which may due to the passive and transpassive mechanism. The corrosion rate was slowly reduced further from 120 to 200 volts. Visually, the positively charged of Cu cable was seems susceptible to severe corrosion, while AC scheme exhibited a slight corrosion reaction on the surface. However, the planned interval test and XRD results showed the corrosion activity of the copper cable in the studied solution was a relatively slow process and considered not to be corroded as a partially protective scale of copper oxide formed on the surface.

Graphene-Based Functional Architectures: Sheets Regulation and Macrostructure Construction toward Actuators and Power Generators.

PubMed

Cheng, Huhu; Huang, Yaxin; Shi, Gaoquan; Jiang, Lan; Qu, Liangti

2017-07-18

Graphene, with large delocalized π electron cloud on a two-dimensional (2D) atom-thin plane, possesses excellent carrier mobility, large surface area, high light transparency, high mechanical strength, and superior flexibility. However, the lack of intrinsic band gap, poor dispersibility, and weak reactivity of graphene hinder its application scope. Heteroatom-doping regulation and surface modification of graphene can effectively reconstruct the sp 2 bonded carbon atoms and tailor the surface chemistry and interfacial interaction, while microstructure mediation on graphene can induce the special chemical and physical properties because of the quantum confinement, edge effect, and unusual mass transport process. Based on these regulations on graphene, series of methods and techniques are developed to couple the promising characters of graphene into the macroscopic architectures for potential and practical applications. In this Account, we present our effort on graphene regulation from chemical modification to microstructure control, from the morphology-designed macroassemblies to their applications in functional systems excluding the energy-storage devices. We first introduce the chemically regulative graphene with incorporated heteroatoms into the honeycomb lattice, which could open the intrinsic band gap and provide many active sites. Then the surface modification of graphene with functional components will improve dispersibility, prevent aggregation, and introduce new functions. On the other hand, microstructure mediation on graphene sheets (e.g., 0D quantum dots, 1D nanoribbons, and 2D nanomeshes) is demonstrated to induce special chemical and physical properties. Benefiting from the effective regulation on graphene sheets, diverse methods including dimension-confined strategy, filtration assembly, and hydrothermal treatment have been developed to assemble individual graphene sheets to macroscopic graphene fibers, films, and frameworks. These rationally regulated graphene sheets and well-constructed assemblies present promising applications in energy-conversion materials and device systems focusing on actuators that can convert different energy forms (e.g., electric, chemical, photonic, thermal, etc.) to mechanical actuation and electrical generators that can directly transform environmental energy to electric power. These results reveal that graphene sheets with surface chemistry and microstructure regulations as well as their rationally designed assemblies provide a promising and abundant platform for development of diverse functional devices. We hope that this Account will promote further efforts toward fundamental research on graphene regulation and the wide applications of advanced designed assemblies in new types of energy-conversion materials/devices and beyond.

Applications of picosecond lasers and pulse-bursts in precision manufacturing

NASA Astrophysics Data System (ADS)

Knappe, Ralf

2012-03-01

Just as CW and quasi-CW lasers have revolutionized the materials processing world, picosecond lasers are poised to change the world of micromachining, where lasers outperform mechanical tools due to their flexibility, reliability, reproducibility, ease of programming, and lack of mechanical force or contamination to the part. Picosecond lasers are established as powerful tools for micromachining. Industrial processes like micro drilling, surface structuring and thin film ablation benefit from a process, which provides highest precision and minimal thermal impact for all materials. Applications such as microelectronics, semiconductor, and photovoltaic industries use picosecond lasers for maximum quality, flexibility, and cost efficiency. The range of parts, manufactured with ps lasers spans from microscopic diamond tools over large printing cylinders with square feet of structured surface. Cutting glass for display and PV is a large application, as well. With a smart distribution of energy into groups of ps-pulses at ns-scale separation (known as burst mode) ablation rates can be increased by one order of magnitude or more for some materials, also providing a better surface quality under certain conditions. The paper reports on the latest results of the laser technology, scaling of ablation rates, and various applications in ps-laser micromachining.

Surface Vibrations and (2x1) Superstructures on FCC(110) Metal Surfaces.

DTIC Science & Technology

1986-06-01

surface physics . In these studies, the application of electron energy loss spectroscopy (EELS) has been shown to be a powerful technique. 1 Information...displacement field u in terms of the eigenstates of the dynamical matrix p2 4 as2 - 1 ,, , ,N ;I/2A( " O;Lzk) t i Xt -iW t S 0; . ; t) a e + a e i(3) z 2M... PHYSICS J A STROSCIO ET AL. UNCLASSIFIED JUN 86 TR-22 N8@814-82-K-B576 F/G 7/4 NL EEEEIIEEIIEEEE IEEEEIIEIIIII EEEEllllllEE L25 L4 11U 11’. 00 00 .CC, 10

Investigation of high voltage spacecraft system interactions with plasma environments

NASA Technical Reports Server (NTRS)

Stevens, N. J.; Berkopec, F. D.; Purvis, C. K.; Grier, N.; Staskus, J. V.

1978-01-01

An experimental investigation was undertaken for insulator and conductor test surfaces biased up to + or - 1kV in a simulated low earth orbit charged particle environment. It was found that these interactions are controlled by the insulator surfaces surrounding the biased conductors. For positive applied voltages the electron current collection can be enhanced by the insulators. For negative applied voltages the insulator surface confines the voltage to the conductor region. Understanding these interactions and the technology to control their impact on system operation is essential to the design of solar cell arrays for ion drive propulsion applications that use direct drive power processing.

Obtaining composite Zr-Al-O coating on the surface of zirconium by microplasma oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gubaidulina, Tatiana A., E-mail: goub2002@mail.ru, E-mail: ostk@mail2000ru; Kuzmin, Oleg S., E-mail: goub2002@mail.ru, E-mail: ostk@mail2000ru; Fedorischva, Marina V., E-mail: fmw@ispms.tsc.ru, E-mail: kmp1980@mail.ru

2014-11-14

The paper describes the application of the microplasma oxidation for production of Zr-Al-O composition on the surface of zirconium. Certification of a new-type power supply for depositing oxide ceramic coatings by microplasma oxidation was also carried out. The growth rate of Zr-Al-O coating amounted around 0.2 nm/s, which around 10 times exceeds that for depositing similar coatings using the similar equipment. We have studied the change of surface morphology and the chemical composition of the formed ceramic coating by means of EVO 50 scanning electron microscope and X-ray spectral analysis.

Screen Cage Ion Plating (SCIP) and scratch testing of polycrystalline aluminum oxide

NASA Technical Reports Server (NTRS)

Spalvins, Talivaldis; Sliney, Harold E.; Deadmore, Daniel L.

1992-01-01

A screen cage ion plating (SCIP) technique was developed to apply silver films on electrically nonconducting aluminum oxide. It is shown that SCIP has remarkable throwing power; surfaces to be coated need not be in direct line of sight with the evaporation source. Scratch tests, employing a diamond stylus with a 200 micro m radius tip, were performed on uncoated and on silver coated alumina. Subsequent surface analysis show that a significant amount of silver remains on the scratched surfaces, even in areas where high stylus load produced severe crack patterns in the ceramic. Friction coefficients were lowered during the scratch tests on the coated alumina indicating that this modification of the ion planting process should be useful for applying lubricating films of soft metals to electrical insulating materials. The very good throwing power of SCIP also strongly suggests general applicability of this process in other areas of technology, e.g., electronics, in addition to tribology.

On-chip manipulation of single microparticles, cells, and organisms using surface acoustic waves.

PubMed

Ding, Xiaoyun; Lin, Sz-Chin Steven; Kiraly, Brian; Yue, Hongjun; Li, Sixing; Chiang, I-Kao; Shi, Jinjie; Benkovic, Stephen J; Huang, Tony Jun

2012-07-10

Techniques that can dexterously manipulate single particles, cells, and organisms are invaluable for many applications in biology, chemistry, engineering, and physics. Here, we demonstrate standing surface acoustic wave based "acoustic tweezers" that can trap and manipulate single microparticles, cells, and entire organisms (i.e., Caenorhabditis elegans) in a single-layer microfluidic chip. Our acoustic tweezers utilize the wide resonance band of chirped interdigital transducers to achieve real-time control of a standing surface acoustic wave field, which enables flexible manipulation of most known microparticles. The power density required by our acoustic device is significantly lower than its optical counterparts (10,000,000 times less than optical tweezers and 100 times less than optoelectronic tweezers), which renders the technique more biocompatible and amenable to miniaturization. Cell-viability tests were conducted to verify the tweezers' compatibility with biological objects. With its advantages in biocompatibility, miniaturization, and versatility, the acoustic tweezers presented here will become a powerful tool for many disciplines of science and engineering.

High-performance shape-engineerable thermoelectric painting

PubMed Central

Park, Sung Hoon; Jo, Seungki; Kwon, Beomjin; Kim, Fredrick; Ban, Hyeong Woo; Lee, Ji Eun; Gu, Da Hwi; Lee, Se Hwa; Hwang, Younghun; Kim, Jin-Sang; Hyun, Dow-Bin; Lee, Sukbin; Choi, Kyoung Jin; Jo, Wook; Son, Jae Sung

2016-01-01

Output power of thermoelectric generators depends on device engineering minimizing heat loss as well as inherent material properties. However, the device engineering has been largely neglected due to the limited flat or angular shape of devices. Considering that the surface of most heat sources where these planar devices are attached is curved, a considerable amount of heat loss is inevitable. To address this issue, here, we present the shape-engineerable thermoelectric painting, geometrically compatible to surfaces of any shape. We prepared Bi2Te3-based inorganic paints using the molecular Sb2Te3 chalcogenidometalate as a sintering aid for thermoelectric particles, with ZT values of 0.67 for n-type and 1.21 for p-type painted materials that compete the bulk values. Devices directly brush-painted onto curved surfaces produced the high output power of 4.0 mW cm−2. This approach paves the way to designing materials and devices that can be easily transferred to other applications. PMID:27834369

Long-term operation of surface high-harmonic generation from relativistic oscillating mirrors using a spooling tape

DOE PAGES

Bierbach, Jana; Yeung, Mark; Eckner, Erich; ...

2015-05-01

Surface high-harmonic generation in the relativistic regime is demonstrated as a source of extreme ultra-violet (XUV) pulses with extended operation time. Relativistic high-harmonic generation is driven by a frequency-doubled high-power Ti:Sapphire laser focused to a peak intensity of 3·1019 W/cm2 onto spooling tapes. We demonstrate continuous operation over up to one hour runtime at a repetition rate of 1 Hz. Harmonic spectra ranging from 20 eV to 70 eV (62 nm to 18 nm) were consecutively recorded by an XUV spectrometer. An average XUV pulse energy in the µJ range is measured. With the presented setup, relativistic surface high-harmonic generationmore » becomes a powerful source of coherent XUV pulses that might enable applications in, e.g. attosecond laser physics and the seeding of free-electron lasers, when the laser issues causing 80-% pulse energy fluctuations are overcome.« less

A shape-adaptive thin-film-based approach for 50% high-efficiency energy generation through micro-grating sliding electrification.

PubMed

Zhu, Guang; Zhou, Yu Sheng; Bai, Peng; Meng, Xian Song; Jing, Qingshen; Chen, Jun; Wang, Zhong Lin

2014-06-18

Effectively harvesting ambient mechanical energy is the key for realizing self-powered and autonomous electronics, which addresses limitations of batteries and thus has tremendous applications in sensor networks, wireless devices, and wearable/implantable electronics, etc. Here, a thin-film-based micro-grating triboelectric nanogenerator (MG-TENG) is developed for high-efficiency power generation through conversion of mechanical energy. The shape-adaptive MG-TENG relies on sliding electrification between complementary micro-sized arrays of linear grating, which offers a unique and straightforward solution in harnessing energy from relative sliding motion between surfaces. Operating at a sliding velocity of 10 m/s, a MG-TENG of 60 cm(2) in overall area, 0.2 cm(3) in volume and 0.6 g in weight can deliver an average output power of 3 W (power density of 50 mW cm(-2) and 15 W cm(-3)) at an overall conversion efficiency of ∼ 50%, making it a sufficient power supply to regular electronics, such as light bulbs. The scalable and cost-effective MG-TENG is practically applicable in not only harvesting various mechanical motions but also possibly power generation at a large scale. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and Application of Laser Peening System for PWR Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masaki Yoda; Itaru Chida; Satoshi Okada

2006-07-01

Laser peening is a process to improve residual stress from tensile to compressive in surface layer of materials by irradiating high-power laser pulses on the material in water. Toshiba has developed a laser peening system composed of Q-switched Nd:YAG laser oscillators, laser delivery equipment and underwater remote handling equipment. We have applied the system for Japanese operating BWR power plants as a preventive maintenance measure for stress corrosion cracking (SCC) on reactor internals like core shrouds or control rod drive (CRD) penetrations since 1999. As for PWRs, alloy 600 or 182 can be susceptible to primary water stress corrosion crackingmore » (PWSCC), and some cracks or leakages caused by the PWSCC have been discovered on penetrations of reactor vessel heads (RVHs), reactor bottom-mounted instrumentation (BMI) nozzles, and others. Taking measures to meet the unconformity of the RVH penetrations, RVHs themselves have been replaced in many PWRs. On the other hand, it's too time-consuming and expensive to replace BMI nozzles, therefore, any other convenient and less expensive measures are required instead of the replacement. In Toshiba, we carried out various tests for laser-peened nickel base alloys and confirmed the effectiveness of laser peening as a preventive maintenance measure for PWSCC. We have developed a laser peening system for PWRs as well after the one for BWRs, and applied it for BMI nozzles, core deluge line nozzles and primary water inlet nozzles of Ikata Unit 1 and 2 of Shikoku Electric Power Company since 2004, which are Japanese operating PWR power plants. In this system, laser oscillators and control devices were packed into two containers placed on the operating floor inside the reactor containment vessel. Laser pulses were delivered through twin optical fibers and irradiated on two portions in parallel to reduce operation time. For BMI nozzles, we developed a tiny irradiation head for small tubes and we peened the inner surface around J-groove welds after laser ultrasonic testing (LUT) as the remote inspection, and we peened the outer surface and the weld for Ikata Unit 2 supplementary. For core deluge line nozzles and primary water inlet nozzles, we peened the inner surface of the dissimilar metal welding, which is of nickel base alloy, joining a safe end and a low alloy metal nozzle. In this paper, the development and the actual application of the laser peening system for PWR power plants will be described. (authors)« less

Effect of plasma-induced surface charging on catalytic processes: application to CO2 activation

NASA Astrophysics Data System (ADS)

Bal, Kristof M.; Huygh, Stijn; Bogaerts, Annemie; Neyts, Erik C.

2018-02-01

Understanding the nature and effect of the multitude of plasma-surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M = Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.

Molecular Machine Powered Surface Programmatic Chain Reaction for Highly Sensitive Electrochemical Detection of Protein.

PubMed

Zhu, Jing; Gan, Haiying; Wu, Jie; Ju, Huangxian

2018-04-17

A bipedal molecular machine powered surface programmatic chain reaction was designed for electrochemical signal amplification and highly sensitive electrochemical detection of protein. The bipedal molecular machine was built through aptamer-target specific recognition for the binding of one target protein with two DNA probes, which hybridized with surface-tethered hairpin DNA 1 (H1) via proximity effect to expose the prelocked toehold domain of H1 for the hybridization of ferrocene-labeled hairpin DNA 2 (H2-Fc). The toehold-mediated strand displacement reaction brought the electrochemical signal molecule Fc close to the electrode and meanwhile released the bipedal molecular machine to traverse the sensing surface by the surface programmatic chain reaction. Eventually, a large number of duplex structures of H1-H2 with ferrocene groups facing to the electrode were formed on the sensor surface to generate an amplified electrochemical signal. Using thrombin as a model target, this method showed a linear detection range from 2 pM to 20 nM with a detection limit of 0.76 pM. The proposed detection strategy was enzyme-free and allowed highly sensitive and selective detection of a variety of protein targets by using corresponding DNA-based affinity probes, showing potential application in bioanalysis.

Antimicrobial Applications of Ambient--Air Plasmas

NASA Astrophysics Data System (ADS)

Pavlovich, Matthew John

The emerging field of plasma biotechology studies the applications of the plasma phase of matter to biological systems. "Ambient-condition" plasmas created at or near room temperature and atmospheric pressure are especially promising for biomedical applications because of their convenience, safety to patients, and compatibility with existing medical technology. Plasmas can be created from many different gases; plasma made from air contains a number of reactive oxygen and nitrogen species, or RONS, involved in various biological processes, including immune activity, signaling, and gene expression. Therefore, ambient-condition air plasma is of particular interest for biological applications. To understand and predict the effects of treating biological systems with ambient-air plasma, it is necessary to characterize and measure the chemical species that these plasmas produce. Understanding both gaseous chemistry and the chemistry in plasma-treated aqueous solution is important because many biological systems exist in aqueous media. Existing literature about ambient-air plasma hypothesizes the critical role of reactive oxygen and nitrogen species; a major aim of this dissertation is to better quantify RONS by produced ambient-air plasma and understand how RONS chemistry changes in response to different plasma processing conditions. Measurements imply that both gaseous and aqueous chemistry are highly sensitive to operating conditions. In particular, chemical species in air treated by plasma exist in either a low-power ozone-dominated mode or a high-power nitrogen oxide-dominated mode, with an unstable transition region at intermediate discharge power and treatment time. Ozone (O3) and nitrogen oxides (NO and NO2, or NOx) are mutually exclusive in this system and that the transition region corresponds to the transition from ozone- to nitrogen oxides-mode. Aqueous chemistry agrees well with to air plasma chemistry, and a similar transition in liquid-phase composition from ozone mode to nitrogen oxides mode occurs as the discharge power increases. One prominent example of plasma biotechnology is the use of plasma-derived reactive species as a novel disinfectant. Ambient-air plasma is an attractive means of disinfection because it is non-thermal, expends a small amount of power, and requires only air and electricity to operate. Both solid surfaces and liquid volumes can be effectively and efficiently decontaminated by the reactive oxygen and nitrogen species that plasma generates. Dry surfaces are decontaminated most effectively by the plasma operating in NOx mode and less effectively in ozone mode, with the weakest antibacterial effects in the transition region, and neutral reactive species are more influential in surface disinfection than charged particles. Aqueous bacterial inactivation correlates well with ozone concentration, suggesting that ozone is the dominant species for bacterial inactivation under the condition of a low-power discharge. Alternatively, air plasma operating in the higher-power, nitrogen oxides-rich mode can create a persistently antibacterial solution. Finally, when near-UV (UVA) treatment follows plasma treatment of bacterial suspension, the antimicrobial effect exceeds the effect predicted from the two treatments alone, and addition of nitrite to aqueous solution, followed by photolysis of nitrite by UVA photons, is hypothesized as the primary mechanism of synergy. The results presented in this dissertation underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications. The complexity of atmospheric pressure plasma devices, and their sensitivity to subtle differences in design and operation, can lead to different results with different mechanisms.

Methods for growth of relatively large step-free SiC crystal surfaces

NASA Technical Reports Server (NTRS)

Neudeck, Philip G. (Inventor); Powell, J. Anthony (Inventor)

2002-01-01

A method for growing arrays of large-area device-size films of step-free (i.e., atomically flat) SiC surfaces for semiconductor electronic device applications is disclosed. This method utilizes a lateral growth process that better overcomes the effect of extended defects in the seed crystal substrate that limited the obtainable step-free area achievable by prior art processes. The step-free SiC surface is particularly suited for the heteroepitaxial growth of 3C (cubic) SiC, AlN, and GaN films used for the fabrication of both surface-sensitive devices (i.e., surface channel field effect transistors such as HEMT's and MOSFET's) as well as high-electric field devices (pn diodes and other solid-state power switching devices) that are sensitive to extended crystal defects.

75 FR 28596 - Bryant Mountain LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... acre-feet and normal water surface elevation of 5500 feet mean sea level; (2) an earthen dam... facility to release water into the stream below the dam; and (4) intake facilities for the power tunnel with facilities to store additional water to provide black start capability. Lower Reservoir (1) Will...

Adaption of Space Station technology for lunar operations

NASA Technical Reports Server (NTRS)

Garvey, J. M.

1988-01-01

The possible use of Space Station technology in a lunar base program is discussed, focusing on the lunar lander/ascent vehicles and surface modules. The application of the Space Station data management system, software, and communications, tracking, guidance, navigation, control, and power technologies is examined. The benefits of utilizing this technology for lunar operations are considered.

Biolayer modeling and optimization for the SPARROW biosensor

NASA Astrophysics Data System (ADS)

Feng, Ke

2007-12-01

Biosensor direct detection of molecular binding events is of significant interest in applications from molecular screening for cancer drug design to bioagent detection for homeland security and defense. The Stacked Planar Affinity Regulated Resonant Optical Waveguide (SPARROW) structure based on coupled waveguides was recently developed to achieve increased sensitivity within a fieldable biosensor device configuration. Under ideal operating conditions, modification of the effective propagation constant of the structure's sensing waveguide through selective attachment of specific targets to probes on the waveguide surface results in a change in the coupling characteristics of the guide over a specifically designed interaction length with the analyte. Monitoring the relative power in each waveguide after interaction enables 'recognition' of those targets which have selectively bound to the surface. However, fabrication tolerances, waveguide interface roughness, biolayer surface roughness and biolayer partial coverage have an effect on biosensor behavior and achievable limit of detection (LOD). In addition to these influences which play a role in device optimization, the influence of the spatially random surface loading of molecular binding events has to be considered, especially for low surface coverage. In this dissertation an analytic model is established for the SPARROW biosensor which accounts for these nonidealities with which the design of the biosensor can be guided and optimized. For the idealized case of uniform waveguide transducer layers and biolayer, both theoretical simulation (analytical expression) and computer simulation (numerical calculation) are completed. For the nonideal case of an inhomogeneous transducer with nonideal waveguide and biolayer surfaces, device output power is affected by such physical influences as surface scattering, coupling length, absorption, and percent coverage of binding events. Using grating and perturbation techniques we explore the influence of imperfect surfaces and random surface loading on scattering loss and coupling length. Results provide a range of achievable limits of detection in the SPARROW device for a given target size, surface loading, and detectable optical power.

Synchroton and Simulations Techniques Applied to Problems in Materials Science: Catalysts and Azul Maya Pigments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chianelli, R.

2005-01-12

Development of synchrotron techniques for the determination of the structure of disordered, amorphous and surface materials has exploded over the past twenty years due to the increasing availability of high flux synchrotron radiation and the continuing development of increasingly powerful synchrotron techniques. These techniques are available to materials scientists who are not necessarily synchrotron scientists through interaction with effective user communities that exist at synchrotrons such as the Stanford Synchrotron Radiation Laboratory (SSRL). In this article we review the application of multiple synchrotron characterization techniques to two classes of materials defined as ''surface compounds.'' One class of surface compounds aremore » materials like MoS{sub 2-x}C{sub x} that are widely used petroleum catalysts used to improve the environmental properties of transportation fuels. These compounds may be viewed as ''sulfide supported carbides'' in their catalytically active states. The second class of ''surface compounds'' is the ''Maya Blue'' pigments that are based on technology created by the ancient Maya. These compounds are organic/inorganic ''surface complexes'' consisting of the dye indigo and palygorskite, a common clay. The identification of both surface compounds relies on the application of synchrotron techniques as described in this report.« less

Large-scale cauliflower-shaped hierarchical copper nanostructures for efficient photothermal conversion.

PubMed

Fan, Peixun; Wu, Hui; Zhong, Minlin; Zhang, Hongjun; Bai, Benfeng; Jin, Guofan

2016-08-14

Efficient solar energy harvesting and photothermal conversion have essential importance for many practical applications. Here, we present a laser-induced cauliflower-shaped hierarchical surface nanostructure on a copper surface, which exhibits extremely high omnidirectional absorption efficiency over a broad electromagnetic spectral range from the UV to the near-infrared region. The measured average hemispherical absorptance is as high as 98% within the wavelength range of 200-800 nm, and the angle dependent specular reflectance stays below 0.1% within the 0-60° incident angle. Such a structured copper surface can exhibit an apparent heating up effect under the sunlight illumination. In the experiment of evaporating water, the structured surface yields an overall photothermal conversion efficiency over 60% under an illuminating solar power density of ∼1 kW m(-2). The presented technology provides a cost-effective, reliable, and simple way for realizing broadband omnidirectional light absorptive metal surfaces for efficient solar energy harvesting and utilization, which is highly demanded in various light harvesting, anti-reflection, and photothermal conversion applications. Since the structure is directly formed by femtosecond laser writing, it is quite suitable for mass production and can be easily extended to a large surface area.

Surface Treatment on Physical Properties and Biocompatibility of Orthodontic Power Chains

PubMed Central

Cheng, H. C.; Chen, M. S.; Peng, B. Y.; Lin, W. T.; Wang, Y. H.

2017-01-01

The conventional orthodontic power chain, often composed of polymer materials, has drawbacks such as a reduction of elasticity owing to water absorption as well as surface discoloration and staining resulting from food or beverages consumed by the patient. The goal of this study was to develop a surface treatment (nanoimprinting) for orthodontic power chains and to alleviate their shortcomings. A concave template (anodic alumina) was manufactured by anodization process using pure aluminum substrate by employing the nanoimprinting process. Convex nanopillars were fabricated on the surface of orthodontic power chains, resulting in surface treatment. Distinct parameters of the nanoimprinting process (e.g., imprinting temperature, imprinting pressure, imprinting time, and demolding temperature) were used to fabricate nanopillars on the surface of orthodontic power chains. The results of this study showed that the contact angle of the power chains became larger after surface treatment. In addition, the power chains changed from hydrophilic to hydrophobic. The power chain before surface treatment without water absorption had a water absorption rate of approximately 4%, whereas a modified chain had a water absorption rate of approximately 2%–4%. Furthermore, the color adhesion of the orthodontic power chains after surface modification was less than that before surface modification. PMID:28540299

Water-cooled, high-intensity ultrasound surgical applicators with frequency tracking.

PubMed

Martin, Roy W; Vaezy, Shahram; Proctor, Andrew; Myntti, Terrence; Lee, Janelle B J; Crum, Lawrence A

2003-10-01

High-intensity, focused ultrasound (HIFU) applicators have been developed for arresting bleeding with the ultimate intent of use in surgery. The design uses a tapered titanium component for transmission coupling of the ultrasound energy from a spherically curved transducer to biological tissues. The nominal operating frequency is 5.5 MHz, in a highly resonant mode (quality factor of 327 with water load). Liquid cooling is used to remove energy loss important at net applied power greater than 18 W/cm2 at the surface of the piezoelectric element. A downward resonance frequency shift (>20 kHz) occurs, even with cooling, as the applicator warms with normal operation. A feedback technique is used for maintaining the excitation near optimum resonance. Standing wave ratios of the applied power of 1.6 or less are thus sustained. The system and applicators have been found to be highly robust, effective in achieving hemostasis in the hemorrhaging liver, spleen, lung, or blood vessels in rabbit and pig experiments. One unit has been operated for over 1.7 hours in treating organ hemorrhage in blunt trauma experiments with nine swine with electrical net power of up to 158 W (31 W/cm2 across the transducer) and intensity of 2560 W/cm2 at focus.

Ocean power technology design optimization

DOE PAGES

van Rij, Jennifer; Yu, Yi -Hsiang; Edwards, Kathleen; ...

2017-07-18

For this study, the National Renewable Energy Laboratory and Ocean Power Technologies (OPT) conducted a collaborative code validation and design optimization study for OPT's PowerBuoy wave energy converter (WEC). NREL utilized WEC-Sim, an open-source WEC simulator, to compare four design variations of OPT's PowerBuoy. As an input to the WEC-Sim models, viscous drag coefficients for the PowerBuoy floats were first evaluated using computational fluid dynamics. The resulting WEC-Sim PowerBuoy models were then validated with experimental power output and fatigue load data provided by OPT. The validated WEC-Sim models were then used to simulate the power performance and loads for operationalmore » conditions, extreme conditions, and directional waves, for each of the four PowerBuoy design variations, assuming the wave environment of Humboldt Bay, California. And finally, ratios of power-to-weight, power-to-fatigue-load, power-to-maximum-extreme-load, power-to-water-plane-area, and power-to-wetted-surface-area were used to make a final comparison of the potential PowerBuoy WEC designs. Lastly, the design comparison methodologies developed and presented in this study are applicable to other WEC devices and may be useful as a framework for future WEC design development projects.« less

Ocean power technology design optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Rij, Jennifer; Yu, Yi -Hsiang; Edwards, Kathleen

For this study, the National Renewable Energy Laboratory and Ocean Power Technologies (OPT) conducted a collaborative code validation and design optimization study for OPT's PowerBuoy wave energy converter (WEC). NREL utilized WEC-Sim, an open-source WEC simulator, to compare four design variations of OPT's PowerBuoy. As an input to the WEC-Sim models, viscous drag coefficients for the PowerBuoy floats were first evaluated using computational fluid dynamics. The resulting WEC-Sim PowerBuoy models were then validated with experimental power output and fatigue load data provided by OPT. The validated WEC-Sim models were then used to simulate the power performance and loads for operationalmore » conditions, extreme conditions, and directional waves, for each of the four PowerBuoy design variations, assuming the wave environment of Humboldt Bay, California. And finally, ratios of power-to-weight, power-to-fatigue-load, power-to-maximum-extreme-load, power-to-water-plane-area, and power-to-wetted-surface-area were used to make a final comparison of the potential PowerBuoy WEC designs. Lastly, the design comparison methodologies developed and presented in this study are applicable to other WEC devices and may be useful as a framework for future WEC design development projects.« less

Applications of low temperature CO-oxidation catalysts to breathable gases

NASA Technical Reports Server (NTRS)

Noordally, Ehsan; Richmond, John R.

1990-01-01

Modifications of tin oxide/precious metal catalysts described for use in CO2 lasers have also been developed for use in other applications; namely, as low temperature CO oxidation components in fire escape hoods/masks for mines, aircrafts, hotels, and offices and in sealed environments, such as hyperbaric chambers and submarines. Tin oxide/precious metal catalysts have been prepared on a variety of high surface area cloth substrates for application in fire escape hoods. These show high and stable CO oxidation capability (10 to the 4th power ppm CO reduced to 10 to the 1st power ppm CO) at GHSV of 37,000 h(-1) with water saturated inlet gas at body heat (37 C) and below. Water vapor plays an important role in the surface state/performance of tin oxide catalyst. Water-resistant formulations have been produced by the introduction of transition metal promoters. Tin oxide/precious metal catalysts have also been developed for CO oxidation in the North Sea diving environment. These are currently in use in a variety of hyperbaric chambers and diving vehicles. Ambient temperature operation and resistance to atmospheric water vapor have been demonstrated, and as a result, they offer a viable alternative to hopcalite or heated catalyst systems. A new range of non-tin oxide based low temperature CO oxidation catalysts is described. They are based on reducible metal oxides promoted with previous metals. Preliminary data on selected materials in the form of both cloth artifacts and shaped pellets are presented. They are expected to be applicable both to the breathable gas application area and to CO2 lasers.

Application Of Optical Processing For Growth Of Silicon Dioxide

DOEpatents

Sopori, Bhushan L.

1997-06-17

A process for producing a silicon dioxide film on a surface of a silicon substrate. The process comprises illuminating a silicon substrate in a substantially pure oxygen atmosphere with a broad spectrum of visible and infrared light at an optical power density of from about 3 watts/cm.sup.2 to about 6 watts/cm.sup.2 for a time period sufficient to produce a silicon dioxide film on the surface of the silicon substrate. An optimum optical power density is about 4 watts/cm.sup.2 for growth of a 100.ANG.-300.ANG. film at a resultant temperature of about 400.degree. C. Deep level transient spectroscopy analysis detects no measurable impurities introduced into the silicon substrate during silicon oxide production and shows the interface state density at the SiO.sub.2 /Si interface to be very low.

FAST TRACK COMMUNICATION: Asymmetric surface barrier discharge plasma driven by pulsed 13.56 MHz power in atmospheric pressure air

NASA Astrophysics Data System (ADS)

Dedrick, J.; Boswell, R. W.; Charles, C.

2010-09-01

Barrier discharges are a proven method of generating plasmas at high pressures, having applications in industrial processing, materials science and aerodynamics. In this paper, we present new measurements of an asymmetric surface barrier discharge plasma driven by pulsed radio frequency (rf 13.56 MHz) power in atmospheric pressure air. The voltage, current and optical emission of the discharge are measured temporally using 2.4 kVp-p (peak to peak) 13.56 MHz rf pulses, 20 µs in duration. The results exhibit different characteristics to plasma actuators, which have similar discharge geometry but are typically driven at frequencies of up to about 10 kHz. However, the electrical measurements are similar to some other atmospheric pressure, rf capacitively coupled discharge systems with symmetric electrode configurations and different feed gases.

Electrode architectures for efficient electronic and ionic transport pathways in high power lithium ion batteries

NASA Astrophysics Data System (ADS)

Faulkner, Ankita Shah

As the demand for clean energy sources increases, large investments have supported R&D programs aimed at developing high power lithium ion batteries for electric vehicles, military, grid storage and space applications. State of the art lithium ion technology cannot meet power demands for these applications due to high internal resistances in the cell. These resistances are mainly comprised of ionic and electronic resistance in the electrode and electrolyte. Recently, much attention has been focused on the use of nanoscale lithium ion active materials on the premise that these materials shorten the diffusion length of lithium ions and increase the surface area for electrochemical charge transfer. While, nanomaterials have allowed significant improvements in the power density of the cell, they are not a complete solution for commercial batteries. Due to their large surface area, they introduce new challenges such as a poor electrode packing densities, high electrolyte reactivity, and expensive synthesis procedures. Since greater than 70% of the cost of the electric vehicle is due to the cost of the battery, a cost-efficient battery design is most critical. To address the limitations of nanomaterials, efficient transport pathways must be engineered in the bulk electrode. As a part of nanomanufacturing research being conducted the Center for High-rate Nanomanufacturing at Northeastern University, the first aim of the proposed work is to develop electrode architectures that enhance electronic and ionic transport pathways in large and small area lithium ion electrodes. These architectures will utilize the unique electronic and mechanical properties of carbon nanotubes to create robust electrode scaffolding that improves electrochemical charge transfer. Using extensive physical and electrochemical characterization, the second aim is to investigate the effect of electrode parameters on electrochemical performance and evaluate the performance against standard commercial electrodes. These parameters include surface morphology, electrode composition, electrode density, and operating temperature. Finally, the third aim is to investigate commercial viability of the electrode architecture. This will be accomplished by developing pouch cell prototypes using a high-rate and low cost scale-up process. Through this work, we aim to realize a commercially viable high-power electrode technology.

Ultracompact/ultralow power electron cyclotron resonance ion source for multipurpose applications.

PubMed

Sortais, P; Lamy, T; Médard, J; Angot, J; Latrasse, L; Thuillier, T

2010-02-01

In order to drastically reduce the power consumption of a microwave ion source, we have studied some specific discharge cavity geometries in order to reduce the operating point below 1 W of microwave power (at 2.45 GHz). We show that it is possible to drive an electron cyclotron resonance ion source with a transmitter technology similar to those used for cellular phones. By the reduction in the size and of the required microwave power, we have developed a new type of ultralow cost ion sources. This microwave discharge system (called COMIC, for COmpact MIcrowave and Coaxial) can be used as a source of light, plasma or ions. We will show geometries of conductive cavities where it is possible, in a 20 mm diameter chamber, to reduce the ignition of the plasma below 100 mW and define typical operating points around 5 W. Inside a simple vacuum chamber it is easy to place the source and its extraction system anywhere and fully under vacuum. In that case, current densities from 0.1 to 10 mA/cm(2) (Ar, extraction 4 mm, 1 mAe, 20 kV) have been observed. Preliminary measurements and calculations show the possibility, with a two electrodes system, to extract beams within a low emittance. The first application for these ion sources is the ion injection for charge breeding, surface analyzing system and surface treatment. For this purpose, a very small extraction hole is used (typically 3/10 mm for a 3 microA extracted current with 2 W of HF power). Mass spectrum and emittance measurements will be presented. In these conditions, values down to 1 pi mm mrad at 15 kV (1sigma) are observed, thus very close to the ones currently observed for a surface ionization source. A major interest of this approach is the possibility to connect together several COMIC devices. We will introduce some new on-going developments such as sources for high voltage implantation platforms, fully quartz radioactive ion source at ISOLDE or large plasma generators for plasma immersion, broad or ribbon beams generation.

Stretchable ultrasonic transducer arrays for three-dimensional imaging on complex surfaces

PubMed Central

Zhu, Xuan; Li, Xiaoshi; Chen, Zeyu; Chen, Yimu; Lei, Yusheng; Li, Yang; Nomoto, Akihiro; Zhou, Qifa; di Scalea, Francesco Lanza

2018-01-01

Ultrasonic imaging has been implemented as a powerful tool for noninvasive subsurface inspections of both structural and biological media. Current ultrasound probes are rigid and bulky and cannot readily image through nonplanar three-dimensional (3D) surfaces. However, imaging through these complicated surfaces is vital because stress concentrations at geometrical discontinuities render these surfaces highly prone to defects. This study reports a stretchable ultrasound probe that can conform to and detect nonplanar complex surfaces. The probe consists of a 10 × 10 array of piezoelectric transducers that exploit an “island-bridge” layout with multilayer electrodes, encapsulated by thin and compliant silicone elastomers. The stretchable probe shows excellent electromechanical coupling, minimal cross-talk, and more than 50% stretchability. Its performance is demonstrated by reconstructing defects in 3D space with high spatial resolution through flat, concave, and convex surfaces. The results hold great implications for applications of ultrasound that require imaging through complex surfaces. PMID:29740603

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: On the possibility of studying the temporal evolution of a surface relief directly during exposure to high-power radiation

NASA Astrophysics Data System (ADS)

Abramov, D. V.; Arakelyan, S. M.; Galkin, A. F.; Klimovskii, Ivan I.; Kucherik, A. O.; Prokoshev, V. G.

2006-06-01

The video image of the graphite surface exposed to focused laser radiation is obtained with the help of a laser monitor. A bright ring moving over the heated surface was observed. A method for reconstructing the surface relief from the video image is proposed and realised. The method is based on the measurement of the angular distribution of the light intensity scattered by the graphite sample surface. The surface relief of the graphite sample changing in time is reconstructed. The relative change in the relief height during laser excitation is measured. The statistical characteristics of the reconstructed graphite surface shape and their variation during laser irradiation are studied. It is found that a circular convexity appears within the bright ring. The formation mechanism of this convexity requires further investigations.

Development Status of PEM Non-Flow-Through Fuel Cell System Technology for NASA Applications

NASA Technical Reports Server (NTRS)

Hoberecht, Mark A.; Jakupca, Ian J.

2011-01-01

Today s widespread development of proton-exchange-membrane (PEM) fuel cell technology for commercial users owes its existence to NASA, where fuel cell technology saw its first applications. Beginning with the early Gemini and Apollo programs, and continuing to this day with the Shuttle Orbiter program, fuel cells have been a primary source of electrical power for many NASA missions. This is particularly true for manned missions, where astronauts are able to make use of the by-product of the fuel cell reaction, potable water. But fuel cells also offer advantages for unmanned missions, specifically when power requirements exceed several hundred watts and primary batteries are not a viable alternative. In recent years, NASA s Exploration Technology Development Program (ETDP) funded the development of fuel cell technology for applications that provide both primary power and regenerative fuel cell energy storage for planned Exploration missions that involved a return to the moon. Under this program, the Altair Lunar Lander was a mission requiring fuel cell primary power. There were also various Lunar Surface System applications requiring regenerative fuel cell energy storage, in which a fuel cell and electrolyzer combine to form an energy storage system with hydrogen, oxygen, and water as common reactants. Examples of these systems include habitat modules and large rovers. In FY11, the ETDP has been replaced by the Enabling Technology Development and Demonstration Program (ETDDP), with many of the same technology goals and requirements applied against NASA s revised Exploration portfolio.

Fission Surface Power Technology Development Status

NASA Technical Reports Server (NTRS)

Palac, Donald T.; Mason, Lee S.; Harlow, Scott

2009-01-01

With the potential future deployment of a lunar outpost there is expected to be a clear need for a high-power, lunar surface power source to support lunar surface operations independent of the day-night cycle, and Fission Surface Power (FSP) is a very effective solution for power levels above a couple 10 s of kWe. FSP is similarly enabling for the poorly illuminated surface of Mars. The power levels/requirements for a lunar outpost option are currently being studied, but it is known that cost is clearly a predominant concern to decision makers. This paper describes the plans of NASA and the DOE to execute an affordable fission surface power system technology development project to demonstrate sufficient technology readiness of an affordable FSP system so viable and cost-effective FSP system options will be available when high power lunar surface system choices are expected to be made in the early 2010s.

Fission Surface Power Technology Development Status

NASA Technical Reports Server (NTRS)

Palac, Donald T.; Mason, Lee S.; Houts, Michael G.; Harlow, Scott

2010-01-01

Power is a critical consideration in planning exploration of the surfaces of the Moon, Mars, and beyond. Nuclear power is an important option, especially for locations in the solar system where sunlight is limited in availability or intensity. NASA is maintaining the option for fission surface power for the Moon and Mars by developing and demonstrating technology for an affordable fission surface power system. Because affordability drove the determination of the system concept that this technology will make possible, low development and recurring costs result, while required safety standards are maintained. However, an affordable approach to fission surface power also provides the benefits of simplicity, robustness, and conservatism in design. This paper will illuminate the multiplicity of benefits to an affordable approach to fission surface power, and will describe how the foundation for these benefits is being developed and demonstrated in the Exploration Technology Development Program s Fission Surface Power Project.

Treatment of PVC using an alternative low energy ion bombardment procedure

NASA Astrophysics Data System (ADS)

Rangel, Elidiane C.; dos Santos, Nazir M.; Bortoleto, José Roberto R.; Durrant, Steven F.; Schreiner, Wido H.; Honda, Roberto Y.; Rangel, Rita de Cássia C.; Cruz, Nilson C.

2011-12-01

In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy increased after the treatment but such modifications were not stable after aging: the contact angle increased for all the samples, modifying the initially hydrophilic surface into a highly hydrophobic one. Consistently, the surface composition also changed after aging: there was carbon enrichment due to further losses of oxygen and chlorine. Another relevant factor for the elevation of θ was the change in morphology induced by the treatment. At greater powers, the uniform matrix of the PVC was transformed into a columnar structure containing randomly distributed sharp pillars. Interpretation of such results is proposed in terms of the total energy deposited in the solid by ionic collisions.

Ultradeep electron cyclotron resonance plasma etching of GaN

DOE PAGES

Harrison, Sara E.; Voss, Lars F.; Torres, Andrea M.; ...

2017-07-25

Here, ultradeep (≥5 μm) electron cyclotron resonance plasma etching of GaN micropillars was investigated. Parametric studies on the influence of the applied radio-frequency power, chlorine content in a Cl 2/Ar etch plasma, and operating pressure on the etch depth, GaN-to-SiO 2 selectivity, and surface morphology were performed. Etch depths of >10 μm were achieved over a wide range of parameters. Etch rates and sidewall roughness were found to be most sensitive to variations in RF power and % Cl 2 in the etch plasma. Selectivities of >20:1 GaN:SiO 2 were achieved under several chemically driven etch conditions where a maximummore » selectivity of ~39:1 was obtained using a 100% Cl 2 plasma. The etch profile and (0001) surface morphology were significantly influenced by operating pressure and the chlorine content in the plasma. Optimized etch conditions yielded >10 μm tall micropillars with nanometer-scale sidewall roughness, high GaN:SiO 2 selectivity, and nearly vertical etch profiles. These results provide a promising route for the fabrication of ultradeep GaN microstructures for use in electronic and optoelectronic device applications. In addition, dry etch induced preferential crystallographic etching in GaN microstructures is also demonstrated, which may be of great interest for applications requiring access to non- or semipolar GaN surfaces.« less

Hall Current Plasma Source Having a Center-Mounted or a Surface-Mounted Cathode

NASA Technical Reports Server (NTRS)

Martinez, Rafael A. (Inventor); Moritz, Jr., Joel A. (Inventor); Williams, John D. (Inventor); Farnell, Casey C. (Inventor)

2018-01-01

A miniature Hall current plasma source apparatus having magnetic shielding of the walls from ionized plasma, an integrated discharge channel and gas distributor, an instant-start hollow cathode mounted to the plasma source, and an externally mounted keeper, is described. The apparatus offers advantages over other Hall current plasma sources having similar power levels, including: lower mass, longer lifetime, lower part count including fewer power supplies, and the ability to be continuously adjustable to lower average power levels using pulsed operation and adjustment of the pulse duty cycle. The Hall current plasma source can provide propulsion for small spacecraft that either do not have sufficient power to accommodate a propulsion system or do not have available volume to incorporate the larger propulsion systems currently available. The present low-power Hall current plasma source can be used to provide energetic ions to assist the deposition of thin films in plasma processing applications.

Enhanced performance of a glucose/O(2) biofuel cell assembled with laccase-covalently immobilized three-dimensional macroporous gold film-based biocathode and bacterial surface displayed glucose dehydrogenase-based bioanode.

PubMed

Hou, Chuantao; Yang, Dapeng; Liang, Bo; Liu, Aihua

2014-06-17

The power output and stability of enzyme-based biofuel cells (BFCs) is greatly dependent on the properties of both the biocathode and bioanode, which may be adapted for portable power production. In this paper, a novel highly uniform three-dimensional (3D) macroporous gold (MP-Au) film was prepared by heating the gold "supraspheres", which were synthesized by a bottom-up protein templating approach, and followed by modification of laccase on the MP-Au film by covalent immobilization. The as-prepared laccase/MP-Au biocathode exihibited an onset potential of 0.62 V versus saturated calomel electrode (SCE, or 0.86 V vs NHE, normal hydrogen electrode) toward O2 reduction and a high catalytic current of 0.61 mAcm(-2). On the other hand, mutated glucose dehydrogenase (GDH) surface displayed bacteria (GDH-bacteria) were used to improve the stability of the glucose oxidation at the bioanode. The as-assembled membraneless glucose/O2 fuel cell showed a high power output of 55.8 ± 2.0 μW cm(-2) and open circuit potential of 0.80 V, contributing to the improved electrocatalysis toward O2 reduction at the laccase/MP-Au biocathode. Moreover, the BFC retained 84% of its maximal power density even after continuous operation for 55 h because of the high stability of the bacterial surface displayed GDH mutant toward glucose oxidation. Our findings may be promising for the development of more efficient glucose BFC for portable battery or self-powered device applications.

Remote Monitoring of Near-Surface Soil Moisture Dynamics In Unstable Slopes Using a Low-Power Autonomous Resistivity Imaging System

NASA Astrophysics Data System (ADS)

Chambers, J. E.; Meldrum, P.; Gunn, D.; Wilkinson, P. B.; Uhlemann, S.; Swift, R. T.; Kuras, O.; Inauen, C.; Hutchinson, D.; Butler, S.

2016-12-01

ERT monitoring has been demonstrated in numerous studies as an effective means of imaging near surface processes for applications as diverse as permafrost studies and contaminated land assessment. A limiting factor in applying time-lapse ERT for long-term studies in remote locations has been the availability of cost-effective ERT measurement systems designed specifically for monitoring applications. Typically, monitoring is undertaken using repeated manual data collection, or by building conventional survey instruments into a monitoring setup. The latter often requires high power and is therefore difficult to operate remotely without access to mains electricity. We describe the development of a low-power resistivity imaging system designed specifically for remote monitoring, taking advantage of, e.g., solar power and data telemetry. Here, we present the results of two field deployments. The system has been installed on an active railway cutting to provide insights into the effect of vegetation on the moisture dynamics in unstable infrastructure slopes and to gather subsurface information for pro-active remediation measures. The system, comprising 255 electrodes, acquires 4596 reciprocal measurement pairs twice daily during standard operation. In case of severe weather events, the measurement schedule is reactively changed, to gather high temporal resolution data to image rainfall infiltration processes. The system has also been installed along a leaking and marginally stable canal embankment; a less favourable location for remote monitoring, with limited solar power and poor mobile reception. Nevertheless, the acquired data indicated the effectiveness of remedial actions on the canal. The ERT results showed that one leak was caused by the canal and fixed during remediation, while two other "leaks" were shown to be effects of groundwater dynamics. The availability of cost-effective, low-power ERT monitoring instrumentation, combined with an automated workflow of data processing and visualisation, has the potential to contribute to a step-change in the management and early warning of slope instability.

Start Up Application Concerns with Field Programmable Gate Arrays (FPGAs)

NASA Technical Reports Server (NTRS)

Katz, Richard B.

1999-01-01

This note is being published to improve the visibility of this subject, as we continue to see problems surface in designs, as well as to add additional information to the previously published note for design engineers. The original application note focused on designing systems with no single point failures using Actel Field Programmable Gate Arrays (FPGAs) for critical applications. Included in that note were the basic principles of operation of the Actel FPGA and a discussion of potential single-point failures. The note also discussed the issue of startup transients for that class of device. It is unfortunate that we continue to see some design problems using these devices. This note will focus on the startup properties of certain electronic components, in general, and current Actel FPGAs, in particular. Devices that are "power-on friendly" are currently being developed by Actel, as a variant of the new SX series of FPGAs. In the ideal world, electronic components would behave much differently than they do in the real world, The chain, of course, starts with the power supply. Ideally, the voltage will immediately rise to a stable V(sub cc) level, of course, it does not. Aside from practical design considerations, inrush current limits of certain capacitors must be observed and the power supply's output may be intentionally slew rate limited to prevent a large current spike on the system power bus. In any event, power supply rise time may range from less than I msec to 100 msec or more.

Predicting surface scatter using a linear systems formulation of non-paraxial scalar diffraction

NASA Astrophysics Data System (ADS)

Krywonos, Andrey

Scattering effects from rough surfaces are non-paraxial diffraction phenomena resulting from random phase variations in the reflected wavefront. The ability to predict these effects is important in a variety of applications including x-ray and EUV imaging, the design of stray light rejection systems, and reflection modeling for rendering realistic scenes and animations of physical objects in computer graphics. Rayleigh-Rice (small perturbation method) and Beckmann-Kirchoff (Kirchhoff approximation) theories are commonly used to predict surface scatter effects. In addition, Harvey and Shack developed a linear systems formulation of surface scatter phenomena in which the scattering behavior is characterized by a surface transfer function. This treatment provided insight and understanding not readily gleaned from the two previous theories, and has been incorporated into a variety of computer software packages (ASAP, Zemax, Tracepro). However, smooth surface and paraxial approximations have severely limited the range of applicability of each of the above theoretical treatments. In this dissertation, a linear systems formulation of non-paraxial scalar diffraction theory is first developed and then applied to sinusoidal phase gratings, resulting in diffraction efficiency predictions far more accurate than those provided by classical scalar theories. The application of the theory to these gratings was motivated by the fact that rough surfaces are frequently modeled as a superposition of sinusoidal surfaces of different amplitudes, periods, and orientations. The application of the non-paraxial scalar diffraction theory to surface scatter phenomena resulted first in a modified Beckmann-Kirchhoff surface scattering model, then a generalized Harvey-Shack theory, both of which produce accurate results for rougher surfaces than the Rayleigh-Rice theory and for larger incident and scattering angles than the classical Beckmann-Kirchhoff theory. These new developments enable the analysis and simplify the understanding of wide-angle scattering behavior from rough surfaces illuminated at large incident angles. In addition, they provide an improved BRDF (Bidirectional Reflectance Distribution Function) model, particularly for the smooth surface inverse scattering problem of determining surface power spectral density (PSD) curves from BRDF measurements.

Design and analysis of 30 nm T-gate InAlN/GaN HEMT with AlGaN back-barrier for high power microwave applications

NASA Astrophysics Data System (ADS)

Murugapandiyan, P.; Ravimaran, S.; William, J.; Meenakshi Sundaram, K.

2017-11-01

In this article, we present the DC and microwave characteristics of a novel 30 nm T-gate InAlN/AlN/GaN HEMT with AlGaN back-barrier. The device structure is simulated by using Synopsys Sentaurus TCAD Drift-Diffusion transport model at room temperature. The device features are heavily doped (n++ GaN) source/drain regions with Si3N4 passivated device surface for reducing the contact resistances and gate capacitances of the device, which uplift the microwave characteristics of the HEMTs. 30 nm gate length D-mode (E-mode) HEMT exhibited a peak drain current density Idmax of 2.3 (2.42) A/mm, transconductance gm of 1.24(1.65) S/mm, current gain cut-off frequency ft of 262 (246) GHz, power gain cut-off frequency fmax of 246(290) GHz and the three terminal off-state breakdown voltage VBR of 40(38) V. The preeminent microwave characteristics with the higher breakdown voltage of the proposed GaN-based HEMT are the expected to be the most optimistic applicant for future high power millimeter wave applications.

Hierarchical Superhydrophobic Surfaces with Micropatterned Nanowire Arrays for High-Efficiency Jumping Droplet Condensation.

PubMed

Wen, Rongfu; Xu, Shanshan; Zhao, Dongliang; Lee, Yung-Cheng; Ma, Xuehu; Yang, Ronggui

2017-12-27

Self-propelled droplet jumping on nanostructured superhydrophobic surfaces is of interest for a variety of industrial applications including self-cleaning, water harvesting, power generation, and thermal management systems. However, the uncontrolled nucleation-induced Wenzel state of condensed droplets at large surface subcooling (high heat flux) leads to the formation of unwanted large pinned droplets, which results in the flooding phenomenon and greatly degrades the heat transfer performance. In this work, we present a novel strategy to manipulate droplet behaviors during the process from the droplet nucleation to growth and departure through a combination of spatially controlling initial nucleation for mobile droplets by closely spaced nanowires and promoting the spontaneous outward movement of droplets for rapid removal using micropatterned nanowire arrays. Through the optical visualization experiments and heat transfer tests, we demonstrate greatly improved condensation heat transfer characteristics on the hierarchical superhydrophobic surface including the higher density of microdroplets, smaller droplet departure radius, 133% wider range of surface subcooling for droplet jumping, and 37% enhancement in critical heat flux for jumping droplet condensation, compared to the-state-of-art jumping droplet condensation on nanostructured superhydrophobic surfaces. The excellent water repellency of such hierarchical superhydrophobic surfaces can be promising for many potential applications, such as anti-icing, antifogging, water desalination, and phase-change heat transfer.

Hierarchical Superhydrophobic Surfaces with Micropatterned Nanowire Arrays for High-Efficiency Jumping Droplet Condensation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wen, Rongfu; Xu, Shanshan; Zhao, Dongliang

Self-propelled droplet jumping on nanostructured superhydrophobic surfaces is of interest for a variety of industrial applications including self-cleaning, water harvesting, power generation, and thermal management systems. However, the uncontrolled nucleation-induced Wenzel state of condensed droplets at large surface subcooling (high heat flux) leads to the formation of unwanted large pinned droplets, which results in the flooding phenomenon and greatly degrades the heat transfer performance. In this work, we present a novel strategy to manipulate droplet behaviors during the process from the droplet nucleation to growth and departure through a combination of spatially controlling initial nucleation for mobile droplets by closelymore » spaced nanowires and promoting the spontaneous outward movement of droplets for rapid removal using micropatterned nanowire arrays. Through the optical visualization experiments and heat transfer tests, we demonstrate greatly improved condensation heat transfer characteristics on the hierarchical superhydrophobic surface including the higher density of microdroplets, smaller droplet departure radius, 133% wider range of surface subcooling for droplet jumping, and 37% enhancement in critical heat flux for jumping droplet condensation, compared to the-state-of-art jumping droplet condensation on nanostructured superhydrophobic surfaces. The excellent water repellency of such hierarchical superhydrophobic surfaces can be promising for many potential applications, such as anti-icing, antifogging, water desalination, and phase-change heat transfer.« less

Hierarchical Superhydrophobic Surfaces with Micropatterned Nanowire Arrays for High-Efficiency Jumping Droplet Condensation

DOE PAGES

Wen, Rongfu; Xu, Shanshan; Zhao, Dongliang; ...

2017-12-07

Self-propelled droplet jumping on nanostructured superhydrophobic surfaces is of interest for a variety of industrial applications including self-cleaning, water harvesting, power generation, and thermal management systems. However, the uncontrolled nucleation-induced Wenzel state of condensed droplets at large surface subcooling (high heat flux) leads to the formation of unwanted large pinned droplets, which results in the flooding phenomenon and greatly degrades the heat transfer performance. In this work, we present a novel strategy to manipulate droplet behaviors during the process from the droplet nucleation to growth and departure through a combination of spatially controlling initial nucleation for mobile droplets by closelymore » spaced nanowires and promoting the spontaneous outward movement of droplets for rapid removal using micropatterned nanowire arrays. Through the optical visualization experiments and heat transfer tests, we demonstrate greatly improved condensation heat transfer characteristics on the hierarchical superhydrophobic surface including the higher density of microdroplets, smaller droplet departure radius, 133% wider range of surface subcooling for droplet jumping, and 37% enhancement in critical heat flux for jumping droplet condensation, compared to the-state-of-art jumping droplet condensation on nanostructured superhydrophobic surfaces. The excellent water repellency of such hierarchical superhydrophobic surfaces can be promising for many potential applications, such as anti-icing, antifogging, water desalination, and phase-change heat transfer.« less

Status of NASA's Advanced Radioisotope Power Conversion Technology Research and Development

NASA Technical Reports Server (NTRS)

Wong, Wayne A.; Anderson, David J.; Tuttle, Karen L.; Tew, Roy C.

2006-01-01

NASA s Advanced Radioisotope Power Systems (RPS) development program is funding the advancement of next generation power conversion technologies that will enable future missions that have requirements that can not be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power Systems (RPS). Requirements of advanced radioisotope power systems include high efficiency and high specific power (watts/kilogram) in order to meet mission requirements with less radioisotope fuel and lower mass. Other Advanced RPS development goals include long-life, reliability, and scalability so that these systems can meet requirements for a variety of future space applications including continual operation surface missions, outer-planetary missions, and solar probe. This paper provides an update on the Radioisotope Power Conversion Technology Project which awarded ten Phase I contracts for research and development of a variety of power conversion technologies consisting of Brayton, Stirling, thermoelectrics, and thermophotovoltaics. Three of the contracts continue during the current Phase II in the areas of thermoelectric and Stirling power conversion. The accomplishments to date of the contractors, project plans, and status will be summarized.

Few layered vanadyl phosphate nano sheets-MWCNT hybrid as an electrode material for supercapacitor application

NASA Astrophysics Data System (ADS)

Dutta, Shibsankar; De, Sukanta

2016-05-01

It have been already seen that 2-dimensional nano materials are the suitable choice for the supercapacitor application due to their large specific surface area, electrochemical active sites, micromechanical flexibility, expedite ion migration channel properties. Free standing hybrid films of functionalized MWCNT (- COOH group) and α-Vanadyl phosphates (VOPO42H2O) are prepared by vacuum filtering. The surface morphology and microstructure of the samples are studied by transmission electron microscope, field emission scanning electron microscope, XRD, Electrochemical properties of hybrid films have been investigated systematically in 1M Na2SO4 aqueous electrolyte. The hybrid material exhibits a high specific capacitance 236 F/g with high energy density of 65.6 Wh/Kg and a power density of 1476 W/Kg.

A practical double-sided frequency selective surface for millimeter-wave applications

NASA Astrophysics Data System (ADS)

Mohyuddin, Wahab; Woo, Dong Sik; Choi, Hyun Chul; Kim, Kang Wook

2018-02-01

Analysis, design, and implementation of a practical, high-rejection frequency selective surface (FSS) are presented in this paper. An equivalent circuit model is introduced for predicting the frequency response of the FSS. The FSS consists of periodic square loop structures fabricated on both sides of the thin dielectric substrate by using the low-cost chemical etching technique. The proposed FSS possesses band-stop characteristics and is implemented to suppress the 170 GHz signal with attenuation of more than 45 dB with insensitivity to an angle of incident plane wave over 20°. Good agreement is observed among calculated, simulated, and measured results. The proposed FSS filter can be used in various millimeter-wave applications such as the protection of imaging diagnostic systems from high spurious input power.

Self-Assembled ZnO Nanosheet-Based Spherical Structure as Photoanode in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Ameri, Mohsen; Raoufi, Meysam; Zamani-Meymian, M.-R.; Samavat, Feridoun; Fathollahi, M.-R.; Mohajerani, Ezeddin

2018-03-01

High surface area and enhanced light scattering of ZnO nanosheet aggregates have made them a promising active layer candidate material for fabrication of nanostructure dye-sensitized solar cells. Here, we propose a facile preparation method of such ZnO nanosheet structures, and in order to verify their applicability as photoanode material for dye-sensitized solar cells, we employ morphological, optical, structural and electrical measurements. The results reveal the high surface area available for dye molecules for enhancing adsorption, high light scattering and competitive power conversion efficiencies compared to the works in literature. Finally, the device is optimized with respect to the photoanode thickness. The favorable features shown here can extend the application of the structure to other types of sensitization-based perovskite and quantum dot solar cells.

Novel applications of X-ray photoelectron spectroscopy on unsupported nanoparticles

NASA Astrophysics Data System (ADS)

Kostko, Oleg; Xu, Bo; Jacobs, Michael I.; Ahmed, Musahid

X-ray photoelectron spectroscopy (XPS) is a powerful technique for chemical analysis of surfaces. We will present novel results of XPS on unsupported, gas-phase nanoparticles using a velocity-map imaging (VMI) spectrometer. This technique allows for probes of both the surfaces of nanoparticles via XPS as well as their interiors via near edge X-ray absorption fine structure (NEXAFS) spectroscopy. A recent application of this technique has confirmed that arginine's guanidinium group exists in a protonated state even in strongly basic solution. Moreover, the core-level photoelectron spectroscopy can provide information on the effective attenuation length (EAL) of low kinetic energy electrons. This contradictory value is important for determining the probing depth of XPS and in photolithography. A new method for determining EALs will be presented.

Creating a zero-order resonator using an optical surface transformation

PubMed Central

Sun, Fei; Ge, Xiaochen; He, Sailing

2016-01-01

A novel zero-order resonator has been designed by an optical surface transformation (OST) method. The resonator proposed here has many novel features. Firstly, the mode volume can be very small (e.g. in the subwavelength scale). Secondly, the resonator is open (no reflecting walls are utilized) and resonant effects can be found in a continuous spectrum (i.e. a continuum of eigenmodes). Thirdly, we only need one homogenous medium to realize the proposed resonator. The shape of the resonator can be a ring structure of arbitrary shape. In addition to the natural applications (e.g. optical storage) of an optical resonator, we also suggest some other applications of our novel optical open resonator (e.g. power combination, squeezing electromagnetic energy in the free space). PMID:26888359

A global plasma model for reactive deposition of compound films by modulated pulsed power magnetron sputtering discharges

NASA Astrophysics Data System (ADS)

Zheng, B. C.; Wu, Z. L.; Wu, B.; Li, Y. G.; Lei, M. K.

2017-05-01

A spatially averaged, time-dependent global plasma model has been developed to describe the reactive deposition of a TiAlSiN thin film by modulated pulsed power magnetron sputtering (MPPMS) discharges in Ar/N2 mixture gas, based on the particle balance and the energy balance in the ionization region, and considering the formation and erosion of the compound at the target surface. The modeling results show that, with increasing the N2 partial pressure from 0% to 40% at a constant working pressure of 0.3 Pa, the electron temperature during the strongly ionized period increases from 4 to 7 eV and the effective power transfer coefficient, which represents the power fraction that effectively heats the electrons and maintains the discharge, increases from about 4% to 7%; with increasing the working pressure from 0.1 to 0.7 Pa at a constant N2 partial pressure of 25%, the electron temperature decreases from 10 to 4 eV and the effective power transfer coefficient decreases from 8% to 5%. Using the modeled plasma parameters to evaluate the kinetic energy of arriving ions, the ion-to-neutral flux ratio of deposited species, and the substrate heating, the variations of process parameters that increase these values lead to an enhanced adatom mobility at the target surface and an increased input energy to the substrate, corresponding to the experimental observation of surface roughness reduction, the microstructure transition from the columnar structure to the dense featureless structure, and the enhancement of phase separation. At higher N2 partial pressure or lower working pressure, the modeling results demonstrate an increase in electron temperature, which shifts the discharge balance of Ti species from Ti+ to Ti2+ and results in a higher return fraction of Ti species, corresponding to the higher Al/Ti ratio of deposited films at these conditions. The modeling results are well correlated with the experimental observation of the composition variation and the microstructure transition of deposited TiAlSiN compound films, demonstrating the applicability of this approach in understanding the characteristics of reactive MPPMS discharges as well as the composition and microstructure of deposited compound films. The model for reactive MPPMS discharges has no special limitations and is applicable to high power impulse magnetron sputtering discharges as well.

An analysis of power beaming for the Moon and Mars

NASA Technical Reports Server (NTRS)

Stavnes, Mark W.

1992-01-01

Operations on the surface of the Moon and Mars will depend on a reliable source of electrical power. At NASA Lewis Research Center, the feasibility of powering lunar and Martian surface sites by power beaming was studied. Constellations of nuclear or solar powered satellites using microwave or laser transmitters were designed to power an equatorial surface base. Additional surface assets, such as rovers, can also be powered from the same orbiting satellites, requiring only the additional mass of a receiver. However, the actual mass and power capabilities of the system are dependent on the location of the surface receiver. The masses of the beam power systems can be reduced by up to 50 percent, by using the power source of an electric propulsion vehicle to power the beam system. The important analyses results and any additional issues that remain unresolved are discussed.

Yeast cell surface display for lipase whole cell catalyst and its applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yun; Zhang, Rui; Lian, Zhongshuai

The cell surface display technique allows for the expression of target proteins or peptides on the microbial cell surface by fusing an appropriate protein as an anchoring motif. Yeast display systems, such as Pichia pastoris, Yarowia lipolytica and Saccharomyces cerevisiae, are ideal, alternative and extensive display systems with the advantage of simple genetic manipulation and post-translational modification of expressed heterologous proteins. Engineered yeasts show high performance characteristics and variant utilizations. Herein, we comprehensively summarize the variant factors affecting lipase whole cell catalyst activity and display efficiency, including the structure and size of target proteins, screening anchor proteins, type and chainmore » length of linkers, and the appropriate matching rules among the above-mentioned display units. Furthermore, we also address novel approaches to enhance stability and activity of recombinant lipases, such as VHb gene co-expression, multi-enzyme co-display technique, and the micro-environmental interference and self-assembly techniques. Finally, we represent the variety of applications of whole cell surface displayed lipases on yeast cells in non-aqueous phases, including synthesis of esters, PUFA enrichment, resolution of chiral drugs, organic synthesis and biofuels. We demonstrate that the lipase surface display technique is a powerful tool for functionalizing yeasts to serve as whole cell catalysts, and increasing interest is providing an impetus for broad application of this technique.« less

High Performance Carbon Nanotube Yarn Supercapacitors with a Surface-Oxidized Copper Current Collector.

PubMed

Zhang, Daohong; Wu, Yunlong; Li, Ting; Huang, Yin; Zhang, Aiqing; Miao, Menghe

2015-11-25

Threadlike linear supercapacitors have demonstrated high potential for constructing fabrics to power electronic textiles (eTextiles). To improve the cyclic electrochemical performance and to produce power fabrics large enough for practical applications, a current collector has been introduced into the linear supercapcitors to transport charges produced by active materials along the length of the supercapacitor with high efficiency. Here, we first screened six candidate metal filaments (Pt, Au, Ag, AuAg, PtCu, and Cu) as current collectors for carbon nanotube (CNT) yarn-based linear supercapacitors. Although all of the metal filaments significantly improved the electrochemical performance of the linear supercapacitor, two supercapacitors constructed from Cu and PtCu filaments, respectively, demonstrate far better electrochemical performance than the other four supercapacitors. Further investigation shows that the surfaces of the two Cu-containing filaments are oxidized by the surrounding polymer electrolyte in the electrode. While the unoxidized core of the Cu-containing filaments remains highly conductive and functions as a current collector, the resulting CuO on the surface is an electrochemically active material. The linear supercapacitor architecture incorporating dual active materials CNT + Cu extends the potential window from 1.0 to 1.4 V, leading to significant improvement to the energy density and power density.

Design of Supercapacitor Electrodes Using Molecular Dynamics Simulations

NASA Astrophysics Data System (ADS)

Bo, Zheng; Li, Changwen; Yang, Huachao; Ostrikov, Kostya; Yan, Jianhua; Cen, Kefa

2018-06-01

Electric double-layer capacitors (EDLCs) are advanced electrochemical devices for energy storage and have attracted strong interest due to their outstanding properties. Rational optimization of electrode-electrolyte interactions is of vital importance to enhance device performance for practical applications. Molecular dynamics (MD) simulations could provide theoretical guidelines for the optimal design of electrodes and the improvement of capacitive performances, e.g., energy density and power density. Here we discuss recent MD simulation studies on energy storage performance of electrode materials containing porous to nanostructures. The energy storage properties are related to the electrode structures, including electrode geometry and electrode modifications. Altering electrode geometry, i.e., pore size and surface topography, can influence EDL capacitance. We critically examine different types of electrode modifications, such as altering the arrangement of carbon atoms, doping heteroatoms and defects, which can change the quantum capacitance. The enhancement of power density can be achieved by the intensified ion dynamics and shortened ion pathway. Rational control of the electrode morphology helps improve the ion dynamics by decreasing the ion diffusion pathway. Tuning the surface properties (e.g., the affinity between the electrode and the ions) can affect the ion-packing phenomena. Our critical analysis helps enhance the energy and power densities of EDLCs by modulating the corresponding electrode structures and surface properties.[Figure not available: see fulltext.

Low power arcjet system spacecraft impacts

NASA Technical Reports Server (NTRS)

Pencil, Eric J.; Sarmiento, Charles J.; Lichtin, D. A.; Palchefsky, J. W.; Bogorad, A. L.

1993-01-01

Application of electrothermal arcjets on communications satellites requires assessment of integration concerns identified by the user community. Perceived risks include plume contamination of spacecraft materials, induced arcing or electrostatic discharges between differentially charged spacecraft surfaces, and conducted and radiated electromagnetic interference (EMI) for both steady state and transient conditions. A Space Act agreement between Martin Marietta Astro Space, the Rocket Research Company, and NASA's Lewis Research Center was established to experimentally examine these issues. Spacecraft materials were exposed to an arcjet plume for 40 hours, representing 40 weeks of actual spacecraft life, and contamination was characterized by changes in surface properties. With the exception of the change in emittance of one sample, all measurable changes in surface properties resulted in acceptable end of life characteristics. Charged spacecraft samples were benignly and consistently reduced to ground potential during exposure to the powered arcjet plume, suggesting that the arcjet could act as a charge control device on spacecraft. Steady state EMI signatures obtained using two different power processing units were similar to emissions measured in a previous test. Emissions measured in UHF, S, C, Ku and Ka bands obtained a null result which verified previous work in the UHF, S, and C bands. Characteristics of conducted and radiated transient emissions appear within standard spacecraft susceptibility criteria.

A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron

PubMed Central

Yuan, Xuesong; Zhu, Weiwei; Zhang, Yu; Xu, Ningsheng; Yan, Yang; Wu, Jianqiang; Shen, Yan; Chen, Jun; She, Juncong; Deng, Shaozhi

2016-01-01

Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun. PMID:27609247

A Fully-Sealed Carbon-Nanotube Cold-Cathode Terahertz Gyrotron.

PubMed

Yuan, Xuesong; Zhu, Weiwei; Zhang, Yu; Xu, Ningsheng; Yan, Yang; Wu, Jianqiang; Shen, Yan; Chen, Jun; She, Juncong; Deng, Shaozhi

2016-09-09

Gigahertz to terahertz radiation sources based on cold-cathode vacuum electron technology are pursued, because its unique characteristics of instant switch-on and power saving are important to military and space applications. Gigahertz gyrotron was reported using carbon nanotube (CNT) cold-cathode. It is reported here in first time that a fully-sealed CNT cold-cathode 0.22 THz-gyrotron is realized, typically with output power of 500 mW. To achieve this, we have studied mechanisms responsible for CNTs growth on curved shape metal surface, field emission from the sidewall of a CNT, and crystallized interface junction between CNT and substrate material. We have obtained uniform growth of CNTs on and direct growth from cone-cylinder stainless-steel electrode surface, and field emission from both tips and sidewalls of CNTs. It is essential for the success of a CNT terahertz gyrotron to have such high quality, high emitting performance CNTs. Also, we have developed a magnetic injection electron gun using CNT cold-cathode to exploit the advantages of such a conventional gun design, so that a large area emitting surface is utilized to deliver large current for electron beam. The results indicate that higher output power and higher radiation frequency terahertz gyrotron may be made using CNT cold-cathode electron gun.

Long life Regenerative Fuel Cell technology development plan

NASA Technical Reports Server (NTRS)

Littman, Franklin D.; Cataldo, Robert L.; Mcelroy, James F.; Stedman, Jay K.

1992-01-01

This paper summarizes a technology roadmap for completing advanced development of a Proton Exchange Membrane (PEM) Regenerative Fuel Cell (RFC) to meet long life (20,000 hrs at 50 percent duty cycle) mobile or portable power system applications on the surface of the moon and Mars. Development of two different sized RFC power system modules is included in this plan (3 and 7.5 kWe). A conservative approach was taken which includes the development of a Ground Engineering System, Qualification Unit, and Flight Unit. This paper includes a concept description, technology assessment, development issues, development tasks, and development schedule.

Growth of porous anodized alumina on the sputtered aluminum films with 2D-3D morphology for high specific surface area

NASA Astrophysics Data System (ADS)

Liao, M. W.; Chung, C. K.

2014-08-01

The porous anodic aluminum oxide (AAO) with high-aspect-ratio pore channels is widely used as a template for fabricating nanowires or other one-dimensional (1D) nanostructures. The high specific surface area of AAO can also be applied to the super capacitor and the supporting substrate for catalysis. The rough surface could be helpful to enhance specific surface area but it generally results in electrical field concentration even to ruin AAO. In this article, the aluminum (Al) films with the varied 2D-3D morphology on Si substrates were prepared using magnetron sputtering at a power of 50 W-185 W for 1 h at a working pressure of 2.5 × 10-1 Pa. Then, AAO was fabricated from the different Al films by means of one-step hybrid pulse anodizing (HPA) between the positive 40 V and the negative -2 V (1 s:1 s) for 3 min in 0.3 M oxalic acid at a room temperature. The microstructure and morphology of Al films were characterized by X-ray diffraction, scanning electron microscope and atomic force microscope, respectively. Some hillocks formed at the high target power could be attributed to the grain texture growth in the normal orientation of Al(1 1 1). The 3D porous AAO structure which is different from the conventional 2D planar one has been successfully demonstrated using HPA on the film with greatly rough hillock-surface formed at the highest power of 185 W. It offers a potential application of the new 3D AAO to high specific surface area devices.

Gain Coupling VECSELs (POSTPRINT)

DTIC Science & Technology

2013-01-01

International Conference on Molecular Beam Epitaxy (MBE-XV). 10. A. Siegman , Lasers , University Sciences Books, 1986. 11. C. Hessenius, N. Terry, M...Clearance Date 28 December 2012. Report contains color. 14. ABSTRACT Vertical external cavity surface emitting lasers (VECSELs) provide a flexible...platform in order to explore curious laser designs and systems as their high-power, high-brightness make them attractive for many applications, and their

77 FR 58369 - York Haven Power Company, LLC; Notice of Application Tendered for Filing With the Commission and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... end of the headrace where it runs diagonally across the main channel of the river approximately 4,970... not used under normal run-of-river operation. The normal water surface elevation of the project...-3 are vertical-shaft, fixed-blade, Kaplan turbines; unit 4 is a vertical-shaft, manually adjustable...

78 FR 26345 - York Haven Power Company, LLC; Notice of Application Accepted for Filing, Soliciting Motions To...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-06

... it runs diagonally across the main channel of the river approximately 4,970 feet to the west shore of... normal run-of-river operation. The normal water surface elevation of the project impoundment is 276.5... appurtenant equipment. The hydraulic equipment for units 1-3 are vertical-shaft, fixed-blade, Kaplan turbines...

Nano-Enabled Technologies for Naval Aviation Applications

DTIC Science & Technology

2015-06-05

4. Reduced self- discharge DEW 1. Active materials (silicon based/anode only); 2. Active materials coated on CNTs surface; 3...polymer film capacitors have the potential to provide higher energy density, higher power density, reduce weight, improve duty cycles (fast discharge and...dependent excess of 200C) 4. Nano-particle dispersion 5. Understanding discharge rate 6. Design and control of the interface 1. Increased

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications

DOEpatents

Tam, Shiu-Wing

1997-01-01

An illumination source comprising a porous silicon having a source of electrons on the surface and/or interticies thereof having a total porosity in the range of from about 50 v/o to about 90 v/o. Also disclosed are a tritiated porous silicon and a photovoltaic device and an illumination source of tritiated porous silicon.

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications

DOEpatents

Tam, Shiu-Wing

1998-01-01

An illumination source comprising a porous silicon having a source of electrons on the surface and/or interticies thereof having a total porosity in the range of from about 50 v/o to about 90 v/o. Also disclosed are a tritiated porous silicon and a photovoltaic device and an illumination source of tritiated porous silicon.

Performance and Safety to NAVSEA Instruction 9310.1A of Lithium-thionyl Chloride Reserve Batteries

NASA Technical Reports Server (NTRS)

Hall, J. C.

1984-01-01

The design, performance and safety of a fully engineered, selfcontained Li/SOCl2 battery as the power source for underwater applications. In addition to meeting the performance standards of the end user this battery is successfully tested under the rigorous safety conditions of NAVSEA Instruction 9310.1A for use on land, aircraft and surface ships.

76 FR 26280 - Vermont Marble Power Division of Omya Inc.; Notice of Application Accepted for Filing, Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

...); (6) an additional steel structure measuring 28 by 48 feet attached to the original powerhouse... maximum water surface elevation of 469.5 feet mean sea level (M.S.L); (3) a gated-forebay intake structure...: A 9-foot- diameter, 460-foot-long, riveted steel penstock that decreases to 8 feet diameter; and a 7...

MIC-Large Scale Magnetically Inflated Cable Structures for Space Power, Propulsion, Communications and Observational Applications

NASA Astrophysics Data System (ADS)

Powell, James; Maise, George; Rather, John

2010-01-01

A new approach for the erection of rigid large scale structures in space-MIC (Magnetically Inflated Cable)-is described. MIC structures are launched as a compact payload of superconducting cables and attached tethers. After reaching orbit, the superconducting cables are energized with electrical current. The magnet force interactions between the cables cause them to expand outwards into the final large structure. Various structural shapes and applications are described. The MIC structure can be a simple flat disc with a superconducting outer ring that supports a tether network holding a solar cell array, or it can form a curved mirror surface that concentrates light and focuses it on a smaller region-for example, a high flux solar array that generates electric power, a high temperature receiver that heats H2 propellant for high Isp propulsion, and a giant primary reflector for a telescope for astronomy and Earth surveillance. Linear dipole and quadrupole MIC structures are also possible. The linear quadrupole structure can be used for magnetic shielding against cosmic radiation for astronauts, for example. MIC could use lightweight YBCO superconducting HTS (High Temperature Superconductor) cables, that can operate with liquid N2 coolant at engineering current densities of ~105 amp/cm2. A 1 kilometer length of MIC cable would weigh only 3 metric tons, including superconductor, thermal insulations, coolant circuits, and refrigerator, and fit within a 3 cubic meter compact package for launch. Four potential MIC applications are described: Solar-thermal propulsion using H2 propellant, space based solar power generation for beaming power to Earth, a large space telescope, and solar electric generation for a manned lunar base. The first 3 applications use large MIC solar concentrating mirrors, while the 4th application uses a surface based array of solar cells on a magnetically levitated MIC structure to follow the sun. MIC space based mirrors can be very large and light in weight. A 300 meter diameter MIC mirror in orbit for example, would weigh 20 metric tons and MIC structures can be easily developed and tested on Earth at small scale in existing evacuated chambers followed by larger scale tests in the atmosphere, using a vacuum tight enclosure on the small diameter superconducting cable to prevent air leakage into the evacuated thermal insulation around the superconducting cable.

Chromatic confocal microscope using hybrid aspheric diffractive lenses

NASA Astrophysics Data System (ADS)

Rayer, Mathieu; Mansfield, Daniel

2014-05-01

A chromatic confocal microscope is a single point non-contact distance measurement sensor. For three decades the vast majority of the chromatic confocal microscope use refractive-based lenses to code the measurement axis chromatically. However, such an approach is limiting the range of applications. In this paper the performance of refractive, diffractive and Hybrid aspheric diffractive are compared. Hybrid aspheric diffractive lenses combine the low geometric aberration of a diffractive lens with the high optical power of an aspheric lens. Hybrid aspheric diffractive lenses can reduce the number of elements in an imaging system significantly or create large hyper- chromatic lenses for sensing applications. In addition, diffractive lenses can improve the resolution and the dynamic range of a chromatic confocal microscope. However, to be suitable for commercial applications, the diffractive optical power must be significant. Therefore, manufacturing such lenses is a challenge. We show in this paper how a theoretical manufacturing model can demonstrate that the hybrid aspheric diffractive configuration with the best performances is achieved by step diffractive surface. The high optical quality of step diffractive surface is then demonstrated experimentally. Publisher's Note: This paper, originally published on 5/10/14, was replaced with a corrected/revised version on 5/19/14. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.

Physicochemical modifications and applications of carbon nano-onions for electrochemical energy storage

NASA Astrophysics Data System (ADS)

Borgohain, Rituraj

Carbon nano-onions (CNOs), concentrically multilayered fullerenes, are prepared by several different methods. We are studying the properties of two specific CNOs: A-CNOs and N-CNOs. A-CNOs are synthesized by underwater arc discharge, and N-CNOs are synthesized by high-temperature graphitization of commercial nanodiamond. In this study the synthesis of A-CNOs are optimized by designing an arc discharge aparatus to control the arc plasma. Moreover other synthesis parameters such as arc power, duty cycles, temperature, graphitic and metal impurities are controlled for optimum production of A-CNOs. Also, a very efficient purification method is developed to screen out A-CNOs from carboneseous and metal impurities. In general, A-CNOs are larger than N-CNOs (ca. 30 nm vs. 7 nm diameter). The high surface area, appropriate mesoporosity, high thermal stability and high electrical conductivity of CNOs make them a promising material for various applications. These hydrophobic materials are functionalized with organic groups on their outer layers to study their surface chemistry and to decorate with metal oxide nanoparticles. Both CNOs and CNO nanocomposites are investigated for application in electrochemical capacitors (ECs). The influences of pH, concentration and additives on the performance of the composites are studied. Electrochemical measurements demonstrate high specific capacitance and high cycling stability with high energy and power density of the composite materials in aqueous electrolyte. Key words: Carbon Nano-onions, Arc discharge, Purification, Functionalization, Supercapacitor.

Mechanically Robust, Stretchable Solar Absorbers with Submicron-Thick Multilayer Sheets for Wearable and Energy Applications.

PubMed

Lee, Hye Jin; Jung, Dae-Han; Kil, Tae-Hyeon; Kim, Sang Hyeon; Lee, Ki-Suk; Baek, Seung-Hyub; Choi, Won Jun; Baik, Jeong Min

2017-05-31

A facile method to fabricate a mechanically robust, stretchable solar absorber for stretchable heat generation and an enhanced thermoelectric generator (TEG) is demonstrated. This strategy is very simple: it uses a multilayer film made of titanium and magnesium fluoride optimized by a two-dimensional finite element frequency-domain simulation, followed by the application of mechanical stresses such as bending and stretching to the film. This process produces many microsized sheets with submicron thickness (∼500 nm), showing great adhesion to any substrates such as fabrics and polydimethylsiloxane. It exhibits a quite high light absorption of approximately 85% over a wavelength range of 0.2-4.0 μm. Under 1 sun illumination, the solar absorber on various stretchable substrates increased the substrate temperature to approximately 60 °C, irrespective of various mechanical stresses such as bending, stretching, rubbing, and even washing. The TEG with the absorber on the top surface also showed an enhanced output power of 60%, compared with that without the absorber. With an incident solar radiation flux of 38.3 kW/m 2 , the output power significantly increased to 24 mW/cm 2 because of the increase in the surface temperature to 141 °C.

Laser-driven formation of a high-pressure phase in amorphous silica.

PubMed

Salleo, Alberto; Taylor, Seth T; Martin, Michael C; Panero, Wendy R; Jeanloz, Raymond; Sands, Timothy; Génin, François Y

2003-12-01

Because of its simple composition, vast availability in pure form and ease of processing, vitreous silica is often used as a model to study the physics of amorphous solids. Research in amorphous silica is also motivated by its ubiquity in modern technology, a prominent example being as bulk material in transmissive and diffractive optics for high-power laser applications such as inertial confinement fusion (ICF). In these applications, stability under high-fluence laser irradiation is a key requirement, with optical breakdown occurring when the fluence of the beam is higher than the laser-induced damage threshold (LIDT) of the material. The optical strength of polished fused silica transmissive optics is limited by their surface LIDT. Surface optical breakdown is accompanied by densification, formation of point defects, cratering, material ejection, melting and cracking. Through a combination of electron diffraction and infrared reflectance measurements we show here that synthetic vitreous silica transforms partially into a defective form of the high-pressure stishovite phase under high-intensity (GW cm(-2)) laser irradiation. This phase transformation offers one suitable mechanism by which laser-induced damage grows catastrophically once initiated, thereby dramatically shortening the service lifetime of optics used for high-power photonics.

Gold Nanorod Rotary Motors Driven by Resonant Light Scattering.

PubMed

Shao, Lei; Yang, Zhong-Jian; Andrén, Daniel; Johansson, Peter; Käll, Mikael

2015-12-22

Efficient and robust artificial nanomotors could provide a variety of exciting possibilities for applications in physics, biology and chemistry, including nanoelectromechanical systems, biochemical sensing, and drug delivery. However, the application of current man-made nanomotors is limited by their sophisticated fabrication techniques, low mechanical output power and severe environmental requirements, making their performance far below that of natural biomotors. Here we show that single-crystal gold nanorods can be rotated extremely fast in aqueous solutions through optical torques dominated by plasmonic resonant scattering of circularly polarized laser light with power as low as a few mW. The nanorods are trapped in 2D against a glass surface, and their rotational dynamics is highly dependent on their surface plasmon resonance properties. They can be kept continuously rotating for hours with limited photothermal side effects and they can be applied for detection of molecular binding with high sensitivity. Because of their biocompatibility, mechanical and thermal stability, and record rotation speeds reaching up to 42 kHz (2.5 million revolutions per minute), these rotary nanomotors could advance technologies to meet a wide range of future nanomechanical and biomedical needs in fields such as nanorobotics, nanosurgery, DNA manipulation and nano/microfluidic flow control.

Simplified correction of B1 inhomogeneity for chemical exchange saturation transfer (CEST) MRI measurement with surface transceiver coil

NASA Astrophysics Data System (ADS)

Sun, Phillip Z.; Zhou, Iris Y.; Igarashi, Takahiro; Guo, Yingkun; Xiao, Gang; Wu, Renhua

2015-03-01

Chemical exchange saturation transfer (CEST) MRI is sensitive to dilute exchangeable protons and local properties such as pH and temperate, yet its susceptibility to field inhomogeneity limits its in vivo applications. Particularly, CEST measurement varies with RF irradiation power, the dependence of which is complex due to concomitant direct RF saturation (RF spillover) effect. Because the volume transmitters provide relatively homogeneous RF field, they have been conventionally used for CEST imaging despite of their elevated specific absorption rate (SAR) and relatively low sensitivity than surface coils. To address this limitation, we developed an efficient B1 inhomogeneity correction algorithm that enables CEST MRI using surface transceiver coils. This is built on recent work that showed the inverse CEST asymmetry analysis (CESTRind) is not susceptible to confounding RF spillover effect. We here postulated that the linear relationship between RF power level and CESTRind can be extended for correcting B1 inhomogeneity induced CEST MRI artifacts. Briefly, we prepared a tissue-like Creatine gel pH phantom and collected multiparametric MRI including relaxation, field map and CEST MRI under multiple RF power levels, using a conventional surface transceiver coil. The raw CEST images showed substantial heterogeneity due to B1 inhomogeneity, with pH contrast to noise ratio (CNR) being 8.8. In comparison, pH MRI CNR of the fieldinhomogeneity corrected CEST MRI was found to be 17.2, substantially higher than that without correction. To summarize, our study validated an efficient field inhomogeneity correction that enables sensitive CEST MRI with surface transceiver, promising for in vivo translation.

Nanoimprint-defined, large-area meta-surfaces for unidirectional optical transmission with superior extinction in the visible-to-infrared range.

PubMed

Yao, Yuhan; Liu, He; Wang, Yifei; Li, Yuanrui; Song, Boxiang; Wang, Richard P; Povinelli, Michelle L; Wu, Wei

2016-07-11

Optical devices with asymmetric transmission have important applications in optical systems, but optical isolators with the modal asymmetry can only be built using magneto-optical or nonlinear materials, as dictated by the Lorentz reciprocity theorem. However, optical devices with the power asymmetry can be achieved by linear materials such as metals and dielectrics. In this paper, we report a large-area, nanoimprint-defined meta-surface (stacked subwavelength gratings) with high-contrast asymmetric transmittance in the visible-to-infrared wavelength range for TM-polarized light. The physical origin of asymmetric transmission through the meta-surface is studied by analyzing the scattering matrix.

Surface Breakdown Characteristics of Silicone Oil for Electric Power Apparatus

NASA Astrophysics Data System (ADS)

Wada, Junichi; Nakajima, Akitoshi; Miyahara, Hideyuki; Takuma, Tadasu; Okabe, Shigemitu; Kohtoh, Masanori; Yanabu, Satoru

This paper describes the surface breakdown characteristics of the silicone oil which has the possibility of the application to innovative switchgear as an insulating medium. At the first step, we have experimentally studied on the impulse breakdown characteristics of the configuration with a triple-junction where a solid insulator is in contact with the electrode. The test configurations consist of solid material (Nomex and pressboard) and liquid insulation oil (silicone and mineral oil). We have discussed the experimental results based on the maximal electric field at a triple-junction. As the second step, we have studied the configuration which may improve the surface breakdown characteristics by lowering the electric field near the triple-junction.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gleicher, Frederick; Ortensi, Javier; DeHart, Mark

Accurate calculation of desired quantities to predict fuel behavior requires the solution of interlinked equations representing different physics. Traditional fuels performance codes often rely on internal empirical models for the pin power density and a simplified boundary condition on the cladding edge. These simplifications are performed because of the difficulty of coupling applications or codes on differing domains and mapping the required data. To demonstrate an approach closer to first principles, the neutronics application Rattlesnake and the thermal hydraulics application RELAP-7 were coupled to the fuels performance application BISON under the master application MAMMOTH. A single fuel pin was modeledmore » based on the dimensions of a Westinghouse 17x17 fuel rod. The simulation consisted of a depletion period of 1343 days, roughly equal to three full operating cycles, followed by a station blackout (SBO) event. The fuel rod was depleted for 1343 days for a near constant total power loading of 65.81 kW. After 1343 days the fission power was reduced to zero (simulating a reactor shut-down). Decay heat calculations provided the time-varying energy source after this time. For this problem, Rattlesnake, BISON, and RELAP-7 are coupled under MAMMOTH in a split operator approach. Each system solves its physics on a separate mesh and, for RELAP-7 and BISON, on only a subset of the full problem domain. Rattlesnake solves the neutronics over the whole domain that includes the fuel, cladding, gaps, water, and top and bottom rod holders. Here BISON is applied to the fuel and cladding with a 2D axi-symmetric domain, and RELAP-7 is applied to the flow of the circular outer water channel with a set of 1D flow equations. The mesh on the Rattlesnake side can either be 3D (for low order transport) or 2D (for diffusion). BISON has a matching ring structure mesh for the fuel so both the power density and local burn up are copied accurately from Rattlesnake. At each depletion time step, Rattlesnake calculates a power density, fission density rate, burn-up distribution and fast flux based on the current water density and fuel temperature. These are then mapped to the BISON mesh for a fuels performance solve. BISON calculates the fuel temperature and cladding surface temperature based upon the current power density and bulk fluid temperature. RELAP-7 then calculates the fluid temperature, water density fraction and water phase velocity based upon the cladding surface temperature. The fuel temperature and the fluid density are then passed back to Rattlesnake for another neutronics calculation. Six Picard or fixed-point style iterations are preformed in this manner to obtain consistent tightly coupled and stable results. For this paper a set of results from the detailed calculation are provided for both during depletion and the SBO event. We demonstrate that a detailed calculation closer to first principles can be done under MAMMOTH between different applications on differing domains.« less

Investigation of antibacterial and wettability behaviours of plasma-modified PMMA films for application in ophthalmology

NASA Astrophysics Data System (ADS)

Rezaei, Fatemeh; Abbasi-Firouzjah, Marzieh; Shokri, Babak

2014-02-01

The main objective of this research is the experimental investigation of the surface properties of polymethyl methacrylate (PMMA) such as wettability and the roughness effect on Escherichia coli (gram negative) cell adhesion. Radio frequency (RF; 13.56 MHz) oxygen plasma was used to enhance the antibacterial and wettability properties of this polymer for biomedical applications, especially ophthalmology. The surface was activated by O2 plasma to produce hydrophilic functional groups. Samples were treated with various RF powers from 10 to 80 W and different gas flow rates from 20 to 120 sccm. Optical emission spectroscopy was used to monitor the plasma process. The modified surface hydrophilicity, morphology and transparency characteristics were studied by water contact angle measurements, atomic force microscopy and UV-vis spectroscopy, respectively. Based on the contact angle measurements of three liquids, surface free energy variations were investigated. Moreover, the antibacterial properties were evaluated utilizing the method of plate counting of Escherichia coli. Also, in order to investigate stability of the plasma treatment, an ageing study was carried out by water contact angle measurements repeated in the days after the treatment. For biomedical applications, especially eye lenses, highly efficient antibacterial surfaces with appropriate hydrophilicity and transparency are of great importance. In this study, it is shown that the plasma process is a reliable and convenient method to achieve these purposes. A significant alteration in the hydrophilicity of a pristine PMMA surface was observed after treatment. Also, our results indicated that the plasma-modified PMMAs exhibit appropriate antibacterial performance. Moreover, surface hydrophilicity and surface charge have more influence on bacterial adhesion rate than surface roughness. UV-vis analysis results do not show a considerable difference for transparency of samples after plasma treatment.

Modeling and simulation of the solar concentrator in photovoltaic systems through the application of a new BRDF function model

NASA Astrophysics Data System (ADS)

Plachta, Kamil

2016-04-01

The paper presents a new algorithm that uses a combination of two models of BRDF functions: Torrance-Sparrow model and HTSG model. The knowledge of technical parameters of a surface is especially useful in the construction of the solar concentrator. The concentrator directs the reflected solar radiation on the surface of photovoltaic panels, increasing the amount of incident radiance. The software applying algorithm allows to calculate surface parameters of the solar concentrator. Performed simulation showing the share of diffuse component and directional component in reflected stream for surfaces made from particular materials. The impact of share of each component in reflected stream on the efficiency of the solar concentrator and photovoltaic surface has also been described. Subsequently, simulation change the value of voltage, current and power output of monocrystalline photovoltaic panels installed in a solar concentrator system has been made for selected surface of materials solar concentrator.

Atomic force microscopy – looking at mechanosensors on the cell surface

PubMed Central

Heinisch, Jürgen J.; Lipke, Peter N.; Beaussart, Audrey; El Kirat Chatel, Sofiane; Dupres, Vincent; Alsteens, David; Dufrêne, Yves F.

2012-01-01

Summary Living cells use cell surface proteins, such as mechanosensors, to constantly sense and respond to their environment. However, the way in which these proteins respond to mechanical stimuli and assemble into large complexes remains poorly understood at the molecular level. In the past years, atomic force microscopy (AFM) has revolutionized the way in which biologists analyze cell surface proteins to molecular resolution. In this Commentary, we discuss how the powerful set of advanced AFM techniques (e.g. live-cell imaging and single-molecule manipulation) can be integrated with the modern tools of molecular genetics (i.e. protein design) to study the localization and molecular elasticity of individual mechanosensors on the surface of living cells. Although we emphasize recent studies on cell surface proteins from yeasts, the techniques described are applicable to surface proteins from virtually all organisms, from bacteria to human cells. PMID:23077172

Energetics of oscillating lifting surfaces using integral conservation laws

NASA Technical Reports Server (NTRS)

Ahmadi, Ali R.; Widnall, Sheila E.

1987-01-01

The energetics of oscillating flexible lifting surfaces in two and three dimensions is calculated by the use of integral conservation laws in inviscid incompressible flow for general and harmonic transverse oscillations. Total thrust is calculated from the momentum theorem and energy loss rate due to vortex shedding in the wake from the principle of conservation of mechanical energy. Total power required to maintain the oscillations and hydrodynamic efficiency are also determined. In two dimensions, the results are obtained in closed form. In three dimensions, the distribution of vorticity on the lifting surface is also required as input to the calculations. Thus, unsteady lifting-surface theory must be used as well. The analysis is applicable to oscillating lifting surfaces of arbitrary planform, aspect ratio, and reduced frequency and does not require calculation of the leading-edge thrust.

High Power Particle Beams and Pulsed Power for Industrial Applications

NASA Astrophysics Data System (ADS)

Bluhm, Hansjoachim; An, Wladimir; Engelko, Wladimir; Giese, Harald; Frey, Wolfgang; Heinzel, Annette; Hoppé, Peter; Mueller, Georg; Schultheiss, Christoph; Singer, Josef; Strässner, Ralf; Strauß, Dirk; Weisenburger, Alfons; Zimmermann, Fritz

2002-12-01

Several industrial scale projects with economic and ecologic potential are presently emanating from research and development in the fields of high power particle beams and pulsed power in Europe. Material surface modifications with large area pulsed electron beams are used to protect high temperature gas turbine blades and steel structures in Pb/Bi cooled accelerator driven nuclear reactor systems against oxidation and corrosion respectively. Channel spark electron beams are applied to deposit bio-compatible or bio-active layers on medical implants. Cell membranes are perforated with strong pulsed electric fields to extract nutritive substances or raw materials from the cells and to kill bacteria for sterilization of liquids. Eletrodynamic fragmentation devices are developed to reutilize concrete aggregates for the production of high quality secondary concrete. All activities have a large potential to contribute to a more sustainable economy.

Hybrid Power Management

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis

2005-01-01

An engineering discipline denoted as hybrid power management (HPM) has emerged from continuing efforts to increase energy efficiency and reliability of hybrid power systems. HPM is oriented toward integration of diverse electric energy-generating, energy-storing, and energy-consuming devices in optimal configurations for both terrestrial and outer-space applications. The basic concepts of HPM are potentially applicable at power levels ranging from nanowatts to megawatts. Potential applications include terrestrial power-generation, terrestrial transportation, biotechnology, and outer-space power systems. Instances of this discipline at prior stages of development were reported (though not explicitly labeled as HPM) in three prior NASA Tech Briefs articles: "Ultracapacitors Store Energy in a Hybrid Electric Vehicle"(LEW-16876), Vol. 24, No. 4 (April 2000), page 63; "Photovoltaic Power Station With Ultracapacitors for Storage" (LEW-17177), Vol. 27, No. 8 (August 2003), page 38; and "Flasher Powered by Photovoltaic Cells and Ultracapacitors" (LEW-17246), Vol. 24, No. 10 (October 2003), page 37. As the titles of the cited articles indicate, the use of ultracapacitors as energy-storage devices lies at the heart of HPM. An ultracapacitor is an electrochemical energy-storage device, but unlike in a conventional rechargeable electrochemical cell or battery, chemical reactions do not take place during operation. Instead, energy is stored electrostatically at an electrode/electrolyte interface. The capacitance per unit volume of an ultracapacitor is much greater than that of a conventional capacitor because its electrodes have much greater surface area per unit volume and the separation between the electrodes is much smaller. Power-control circuits for ultracapacitors can be simpler than those for batteries, for two reasons: (1) Because of the absence of chemical reactions, charge and discharge currents can be greater than those in batteries, limited only by the electrical resistances of conductors; and (2) whereas the charge level of a battery depends on voltage, temperature, age, and load condition, the charge level of an ultracapacitor, like that of a conventional capacitor, depends only on voltage.

Space nuclear power systems 1989; Proceedings of the 6th Symposium, Albuquerque, NM, Jan. 8-12, 1989. Vols. 1 & 2

NASA Technical Reports Server (NTRS)

El-Genk, Mohamed S. (Editor); Hoover, Mark D. (Editor)

1992-01-01

The present conference discusses such space nuclear power (SNP) issues as current design trends for SDI applications, ultrahigh heat-flux systems with curved surface subcooled nucleate boiling, design and manufacturing alternatives for low cost production of SNPs, a lightweight radioisotope heater for the Galileo mission, compatible materials for uranium fluoride-based gas core SNPs, Johnson noise thermometry for SNPs, and uranium nitride/rhenium compatibility studies for the SP-100 SNP. Also discussed are system issues in antimatter energy conversion, the thermal design of a heat source for a Brayton cycle radioisotope power system, structural and thermal analyses of an isotope heat source, a novel plant protection strategy for transient reactors, and beryllium toxicity.

Effect of Diode Laser Irradiation Combined with Topical Fluoride on Enamel Microhardness of Primary Teeth.

PubMed

Bahrololoomi, Zahra; Lotfian, Malihe

2015-02-01

Laser irradiation has been suggested as an adjunct to traditional caries prevention methods. But little is known about the cariostatic effect of diode laser and most studies available are on permanent teeth.The purpose of the present study was to investigate the effect of diode laser irradiation combined with topical fluoride on enamel surface microhardness. Forty-five primary teeth were used in this in vitro study. The teeth were sectioned to produce 90 slabs. The baseline Vickers microhardness number of each enamel surface was determined. The samples were randomly divided into 3 groups. Group 1: 5% NaF varnish, group 2: NaF varnish+ diode laser at 5 W power and group 3: NaF varnish+ diode laser at 7 W power. Then, the final microhardness number of each surface was again determined. The data were statistically analyzed by repeated measures ANOVA at 0.05 level of significance. In all 3 groups, microhardness number increased significantly after surface treatment (P<0.05). However, Microhardness change after treatment was not significantly different among groups (P >0.05). The combined application of diode laser and topical fluoride varnish on enamel surface did not show any significant additional effect on enamel resistance to caries.

Wireless Acoustic-Surface Actuators for Miniaturized Endoscopes.

PubMed

Qiu, Tian; Adams, Fabian; Palagi, Stefano; Melde, Kai; Mark, Andrew; Wetterauer, Ulrich; Miernik, Arkadiusz; Fischer, Peer

2017-12-13

Endoscopy enables minimally invasive procedures in many medical fields, such as urology. However, current endoscopes are normally cable-driven, which limits their dexterity and makes them hard to miniaturize. Indeed, current urological endoscopes have an outer diameter of about 3 mm and still only possess one bending degree-of-freedom. In this article, we report a novel wireless actuation mechanism that increases the dexterity and that permits the miniaturization of a urological endoscope. The novel actuator consists of thin active surfaces that can be readily attached to any device and are wirelessly powered by ultrasound. The surfaces consist of two-dimensional arrays of microbubbles, which oscillate under ultrasound excitation and thereby generate an acoustic streaming force. Bubbles of different sizes are addressed by their unique resonance frequency, thus multiple degrees-of-freedom can readily be incorporated. Two active miniaturized devices (with a side length of around 1 mm) are demonstrated: a miniaturized mechanical arm that realizes two degrees-of-freedom, and a flexible endoscope prototype equipped with a camera at the tip. With the flexible endoscope, an active endoscopic examination is successfully performed in a rabbit bladder. The results show the potential medical applicability of surface actuators wirelessly powered by ultrasound penetrating through biological tissues.

Effective micro-spray cooling for light-emitting diode with graphene nanoporous layers

NASA Astrophysics Data System (ADS)

Keong Lay, Kok; Yew Cheong, Brian Mun; Li Tong, Wei; Tan, Ming Kwang; Hung, Yew Mun

2017-04-01

A graphene nanoplatelet (GNP) coating is utilized as a functionalized surface in enhancing the evaporation rate of micro-spray cooling for light-emitting diodes (LEDs). In micro-spray cooling, water is atomized into micro-sized droplets to reduce the surface energy and to increase the surface area for evaporation. The GNP coating facilitates the effective filmwise evaporation through the attribute of fast water permeation. The oxygenated functional groups of GNPs provide the driving force that initiates the intercalation of water molecules through the carbon nanostructure. The water molecules slip through the frictionless passages between the hydrophobic carbon walls, resulting an effective filmwise evaporation. The enhancement of evaporation leads to an enormous temperature reduction of 61.3 °C. The performance of the LED is greatly enhanced: a maximum increase in illuminance of 25% and an extension of power rating from 9 W to 12 W can be achieved. With the application of GNP coating, the high-temperature region is eliminated while maintaining the LED surface temperature for optimal operation. This study paves the way for employing the effective hybrid spray-evaporation-nanostructure technique in the development of a compact, low-power-consumption cooling system.

Investigations of the fabrication and the surface-enhanced Raman scattering detection applications for tapered fiber probes prepared with the laser-induced chemical deposition method.

PubMed

Fan, Qunfang; Cao, Jie; Liu, Ye; Yao, Bo; Mao, Qinghe

2013-09-01

The process of depositing nanoparticles onto tapered fiber probes with the laser-induced chemical deposition method (LICDM) and the surface-enhanced Raman scattering (SERS) detection performance of the prepared probes are experimentally investigated in this paper. Our results show that the nanoparticle-deposited tapered fiber probes prepared with the LICDM method depend strongly on the value of the cone angle. For small-angle tapered probes the nanoparticle-deposited areas are only focused at the taper tips, because the taper surfaces are mainly covered by a relatively low-intensity evanescent field. By lengthening the reaction time or increasing the induced power or solution concentration, it is still possible to deposit nanoparticles on small-angle tapers with the light-scattering effect. With 4-aminothiophenol as the testing molecule, it was found that for given preparation conditions, the cone angles for the tapered probes with the highest SERS spectral intensities for different excitation laser powers are almost the same. However, such an optimal cone angle is determined by the combined effects of both the localized surface plasmon resonance strength and the transmission loss generated by the nanoparticles deposited.

Wireless Acoustic-Surface Actuators for Miniaturized Endoscopes

PubMed Central

2017-01-01

Endoscopy enables minimally invasive procedures in many medical fields, such as urology. However, current endoscopes are normally cable-driven, which limits their dexterity and makes them hard to miniaturize. Indeed, current urological endoscopes have an outer diameter of about 3 mm and still only possess one bending degree-of-freedom. In this article, we report a novel wireless actuation mechanism that increases the dexterity and that permits the miniaturization of a urological endoscope. The novel actuator consists of thin active surfaces that can be readily attached to any device and are wirelessly powered by ultrasound. The surfaces consist of two-dimensional arrays of microbubbles, which oscillate under ultrasound excitation and thereby generate an acoustic streaming force. Bubbles of different sizes are addressed by their unique resonance frequency, thus multiple degrees-of-freedom can readily be incorporated. Two active miniaturized devices (with a side length of around 1 mm) are demonstrated: a miniaturized mechanical arm that realizes two degrees-of-freedom, and a flexible endoscope prototype equipped with a camera at the tip. With the flexible endoscope, an active endoscopic examination is successfully performed in a rabbit bladder. The results show the potential medical applicability of surface actuators wirelessly powered by ultrasound penetrating through biological tissues. PMID:29148713

New 2D diffraction model and its applications to terahertz parallel-plate waveguide power splitters

PubMed Central

Zhang, Fan; Song, Kaijun; Fan, Yong

2017-01-01

A two-dimensional (2D) diffraction model for the calculation of the diffraction field in 2D space and its applications to terahertz parallel-plate waveguide power splitters are proposed in this paper. Compared with the Huygens-Fresnel principle in three-dimensional (3D) space, the proposed model provides an approximate analytical expression to calculate the diffraction field in 2D space. The diffraction filed is regarded as the superposition integral in 2D space. The calculated results obtained from the proposed diffraction model agree well with the ones by software HFSS based on the element method (FEM). Based on the proposed 2D diffraction model, two parallel-plate waveguide power splitters are presented. The splitters consist of a transmitting horn antenna, reflectors, and a receiving antenna array. The reflector is cylindrical parabolic with superimposed surface relief to efficiently couple the transmitted wave into the receiving antenna array. The reflector is applied as computer-generated holograms to match the transformed field to the receiving antenna aperture field. The power splitters were optimized by a modified real-coded genetic algorithm. The computed results of the splitters agreed well with the ones obtained by software HFSS verify the novel design method for power splitter, which shows good applied prospects of the proposed 2D diffraction model. PMID:28181514

In Situ Oxidation Synthesis of p-Type Composite with Narrow-Bandgap Small Organic Molecule Coating on Single-Walled Carbon Nanotube: Flexible Film and Thermoelectric Performance.

PubMed

Gao, Caiyan; Chen, Guangming

2018-03-01

Although composites of organic polymers or n-type small molecule/carbon nanotube (CNT) have achieved significant advances in thermoelectric (TE) applications, p-type TE composites of small organic molecules as thick surface coating layers on the surfaces of inorganic nanoparticles still remain a great challenge. Taking advantage of in situ oxidation reaction of thieno[3,4-b]pyrazine (TP) into TP di-N-oxide (TPNO) on single-walled CNT (SWCNT) surface, a novel synthesis strategy is proposed to achieve flexible films of TE composites with narrow-bandgap (1.19 eV) small molecule coating on SWCNT surface. The TE performance can be effectively enhanced and conveniently tuned by poly(sodium-p-styrenesulfonate) content, TPNO/SWCNT mass ratio, and posttreatment by various polar solvents. The maximum of the composite power factor at room temperature is 29.4 ± 1.0 µW m -1 K -2 . The work presents a way to achieve flexible films of p-type small organic molecule/inorganic composites with clear surface coating morphology for TE application. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New Technology for Microfabrication and Testing of a Thermoelectric Device for Generating Mobile Electrical Power

NASA Technical Reports Server (NTRS)

Prasad, Narashimha S.; Taylor, Patrick J.; Trivedi, Sudhir B.; Kutcher, Susan

2010-01-01

We report the results of fabrication and testing of a thermoelectric power generation module. The module was fabricated using a new "flip-chip" module assembly technique that is scalable and modular. This technique results in a low value of contact resistivity ( < or = 10(exp 5) Ohms-sq cm). It can be used to leverage new advances in thin-film and nanostructured materials for the fabrication of new miniature thermoelectric devices. It may also enable monolithic integration of large devices or tandem arrays of devices on flexible or curved surfaces. Under mild testing, a power of 22 mW/sq cm was obtained from small (<100 K) temperature differences. At higher, more realistic temperature differences, approx.500 K, where the efficiency of these materials greatly improves, this power density would scale to between 0.5 and 1 Watt/cm2. These results highlight the excellent potential for the generation and scavenging of electrical power of practical and usable magnitude for remote applications using thermoelectric power generation technologies.

A Wireless Self-Powered Urinary Incontinence Sensor System

NASA Astrophysics Data System (ADS)

Tanaka, Ami; Utsunomiya, Fumiyasu; Douseki, Takakuni

A self-powered urinary incontinence sensor system consisting of a urine-activated coin battery and a wireless transmitter has been developed as an application for wireless biosensor networks. The urine-activated battery makes possible both the sensing of urine leakage and self-powered operation. An intermittent power-supply circuit that uses an electric double-layer capacitor (EDLC) with a small internal resistance suppresses the supply voltage drop due to the large internal resistance of the battery. This circuit and a 1-V surface acoustic wave (SAW) oscillator reduce the power dissipation of a wireless transmitter. The SAW oscillator quickly responds to the on-off control of the power supply, which is suitable for intermittent operation. To verify the effectiveness of the circuit scheme, the authors fabricated a prototype sensor system. When the volume of urine is 0.2 ml, the battery outputs a voltage of over 1.3 V; and the sensor system can transmit signals over a distance of 5 m.

Direct glass bonded high specific power silicon solar cells for space applications

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Rand, J. A.; Cummings, J. R.; Lampo, S. M.; Shreve, K. P.; Barnett, Allen M.

1991-01-01

A lightweight, radiation hard, high performance, ultra-thin silicon solar cell is described that incorporates light trapping and a cover glass as an integral part of the device. The manufacturing feasibility of high specific power, radiation insensitive, thin silicon solar cells was demonstrated experimentally and with a model. Ultra-thin, light trapping structures were fabricated and the light trapping demonstrated experimentally. The design uses a micro-machined, grooved back surface to increase the optical path length by a factor of 20. This silicon solar cell will be highly tolerant to radiation because the base width is less than 25 microns making it insensitive to reduction in minority carrier lifetime. Since the silicon is bonded without silicone adhesives, this solar cell will also be insensitive to UV degradation. These solar cells are designed as a form, fit, and function replacement for existing state of the art silicon solar cells with the effect of simultaneously increasing specific power, power/area, and power supply life. Using a 3-mil thick cover glass and a 0.3 g/sq cm supporting Al honeycomb, a specific power for the solar cell plus cover glass and honeycomb of 80.2 W/Kg is projected. The development of this technology can result in a revolutionary improvement in high survivability silicon solar cell products for space with the potential to displace all existing solar cell technologies for single junction space applications.

Sudurnes Regional Heating Corp.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lienau, P.J.

1996-11-01

The Svartsengi geothermal area is close to the town of Grindavik on the Rekjanes peninsula and is part of an active fissure swarm, lined with crater-rows and open fissures and faults. The high-temperature area has an area of 2 sq. km and shows only limited signs of geothermal activity at the surface. The reservoir, however, contains lots of energy and at least 8 wells supply the Svartsengi Power Plant with steam. The steam is not useable for domestic heating purposes so that heat exchangers are used to heat cold groundwater with the steam. Some steam is also used for producingmore » 16.4 MW{sub e} of electrical power. The article shows the distribution system piping hot water to nine towns and the Keflavik International Airport. The effluent brine from the Svartsengi Plant is disposed of into a surface pond, called the Blue Lagoon, popular to tourists and people suffering from psoriasis and other forms of eczema seeking therapeutic effects from the silica rich brine. This combined power plant and regional district heating system (cogeneration) is an interesting and unique design for the application of geothermal energy.« less

Solar vs. Fission Surface Power for Mars

NASA Technical Reports Server (NTRS)

Rucker, Michelle A.; Oleson, Steve; George, Pat; Landis, Geoffrey A.; Fincannon, James; Bogner, Amee; Jones, Robert E.; Turnbull, Elizabeth; Martini, Michael C.; Gyekenyesi, John Z.;

Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics.

PubMed

Pourghodrat, Abolfazl; Nelson, Carl A

2017-03-01

Fusion of robotics and minimally invasive surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems to miniature in-vivo robotics. However, with miniaturization of electric-motor-driven surgical robots, there comes a trade-off between the size of the robot and its capability. Slow actuation, low load capacity, sterilization difficulties, leaking electricity and transferring produced heat to tissues, and high cost are among the key limitations of the use of electric motors in in-vivo applications. Fluid power in the form of hydraulics or pneumatics has a long history in driving many industrial devices and could be exploited to circumvent these limitations. High power density and good compatibility with the in-vivo environment are the key advantages of fluid power over electric motors when it comes to in-vivo applications. However, fabrication of hydraulic/pneumatic actuators within the desired size and pressure range required for in-vivo surgical robotic applications poses new challenges. Sealing these types of miniature actuators at operating pressures requires obtaining very fine surface finishes which is difficult and costly. The research described here presents design, fabrication, and testing of a hydraulic/pneumatic double-acting cylinder, a limited-motion vane motor, and a balloon-actuated laparoscopic grasper. These actuators are small, seal-less, easy to fabricate, disposable, and inexpensive, thus ideal for single-use in-vivo applications. To demonstrate the ability of these actuators to drive robotic joints, they were modified and integrated in a robotic arm. The design and testing of this surgical robotic arm are presented to validate the concept of fluid-power actuators for in-vivo applications.

Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics

PubMed Central

Pourghodrat, Abolfazl; Nelson, Carl A.

2017-01-01

Fusion of robotics and minimally invasive surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems to miniature in-vivo robotics. However, with miniaturization of electric-motor-driven surgical robots, there comes a trade-off between the size of the robot and its capability. Slow actuation, low load capacity, sterilization difficulties, leaking electricity and transferring produced heat to tissues, and high cost are among the key limitations of the use of electric motors in in-vivo applications. Fluid power in the form of hydraulics or pneumatics has a long history in driving many industrial devices and could be exploited to circumvent these limitations. High power density and good compatibility with the in-vivo environment are the key advantages of fluid power over electric motors when it comes to in-vivo applications. However, fabrication of hydraulic/pneumatic actuators within the desired size and pressure range required for in-vivo surgical robotic applications poses new challenges. Sealing these types of miniature actuators at operating pressures requires obtaining very fine surface finishes which is difficult and costly. The research described here presents design, fabrication, and testing of a hydraulic/pneumatic double-acting cylinder, a limited-motion vane motor, and a balloon-actuated laparoscopic grasper. These actuators are small, seal-less, easy to fabricate, disposable, and inexpensive, thus ideal for single-use in-vivo applications. To demonstrate the ability of these actuators to drive robotic joints, they were modified and integrated in a robotic arm. The design and testing of this surgical robotic arm are presented to validate the concept of fluid-power actuators for in-vivo applications. PMID:28070227

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bierbach, Jana; Yeung, Mark; Eckner, Erich

Surface high-harmonic generation in the relativistic regime is demonstrated as a source of extreme ultra-violet (XUV) pulses with extended operation time. Relativistic high-harmonic generation is driven by a frequency-doubled high-power Ti:Sapphire laser focused to a peak intensity of 3·1019 W/cm2 onto spooling tapes. We demonstrate continuous operation over up to one hour runtime at a repetition rate of 1 Hz. Harmonic spectra ranging from 20 eV to 70 eV (62 nm to 18 nm) were consecutively recorded by an XUV spectrometer. An average XUV pulse energy in the µJ range is measured. With the presented setup, relativistic surface high-harmonic generationmore » becomes a powerful source of coherent XUV pulses that might enable applications in, e.g. attosecond laser physics and the seeding of free-electron lasers, when the laser issues causing 80-% pulse energy fluctuations are overcome.« less

Synthesis and characterization of transition metal oxide/sulfide nanostructures for electrochemical applications

NASA Astrophysics Data System (ADS)

Yilmaz, Gamze

This thesis is essentially oriented to develop low-cost nanostructured transition metal (nickel and vanadium) oxides and sulfides with high energy density, power density and electrochemical stability via strategies of structural design, hybridization, functionalization and surface engineering. Metal oxide and metal oxide/sulfide hybrid nanostructures in several designs, including hierarchical porous nanostructures, hollow polyhedrons, nanocubes, nanoframes, octopod nanoframes, and nanocages, were synthesized to study the contribution of structural design, compositional engineering, functionalization and surface engineering to the electrochemical properties of the materials. Modulated compositional and structural features disclosed the opportunities of large accessible active sites, facile ion transport, robustness and enhanced electrical conductivity. The best electrochemical performance with merits of highest energy density (38.9 Wh kg-1), power density (7.4 kW kg-1) and electrochemical stability (90.9% after 10000 cycles) was obtained for nickel cobalt layered double hydroxide/cobalt sulfide (NiCo-LDH/Co9S8) hybrid hollow polyhedron structure.

A post-processing method to simulate the generalized RF sheath boundary condition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myra, James R.; Kohno, Haruhiko

For applications of ICRF power in fusion devices, control of RF sheath interactions is of great importance. A sheath boundary condition (SBC) was previously developed to provide an effective surface impedance for the interaction of the RF sheath with the waves. The SBC enables the surface power flux and rectified potential energy available for sputtering to be calculated. For legacy codes which cannot easily implement the SBC, or to speed convergence in codes which do implement it, we consider here an approximate method to simulate SBCs by post-processing results obtained using other, e.g. conducting wall, boundary conditions. The basic approximationmore » is that the modifications resulting from the generalized SBC are driven by a fixed incoming wave which could be either a fast wave or a slow wave. Finally, the method is illustrated in slab geometry and compared with exact numerical solutions; it is shown to work very well.« less

A post-processing method to simulate the generalized RF sheath boundary condition

DOE PAGES

Myra, James R.; Kohno, Haruhiko

2017-10-23

For applications of ICRF power in fusion devices, control of RF sheath interactions is of great importance. A sheath boundary condition (SBC) was previously developed to provide an effective surface impedance for the interaction of the RF sheath with the waves. The SBC enables the surface power flux and rectified potential energy available for sputtering to be calculated. For legacy codes which cannot easily implement the SBC, or to speed convergence in codes which do implement it, we consider here an approximate method to simulate SBCs by post-processing results obtained using other, e.g. conducting wall, boundary conditions. The basic approximationmore » is that the modifications resulting from the generalized SBC are driven by a fixed incoming wave which could be either a fast wave or a slow wave. Finally, the method is illustrated in slab geometry and compared with exact numerical solutions; it is shown to work very well.« less

Application of optical processing for growth of silicon dioxide

DOEpatents

Sopori, B.L.

1997-06-17

A process for producing a silicon dioxide film on a surface of a silicon substrate is disclosed. The process comprises illuminating a silicon substrate in a substantially pure oxygen atmosphere with a broad spectrum of visible and infrared light at an optical power density of from about 3 watts/cm{sup 2} to about 6 watts/cm{sup 2} for a time period sufficient to produce a silicon dioxide film on the surface of the silicon substrate. An optimum optical power density is about 4 watts/cm{sup 2} for growth of a 100{angstrom}-300{angstrom} film at a resultant temperature of about 400 C. Deep level transient spectroscopy analysis detects no measurable impurities introduced into the silicon substrate during silicon oxide production and shows the interface state density at the SiO{sub 2}/Si interface to be very low. 1 fig.

Synthetic schlieren—application to the visualization and characterization of air convection

NASA Astrophysics Data System (ADS)

Taberlet, Nicolas; Plihon, Nicolas; Auzémery, Lucile; Sautel, Jérémy; Panel, Grégoire; Gibaud, Thomas

2018-05-01

Synthetic schlieren is a digital image processing optical method relying on the variation of optical index to visualize the flow of a transparent fluid. In this article, we present a step-by-step, easy-to-implement and affordable experimental realization of this technique. The method is applied to air convection caused by a warm surface. We show that the velocity of rising convection plumes can be linked to the temperature of the warm surface and propose a simple physical argument to explain this dependence. Moreover, using this method, one can reveal the tenuous convection plumes rising from one’s hand, a phenomenon invisible to the naked eye. This spectacular result may help students to realize the power of careful data acquisition combined with astute image processing techniques. This spectacular result may help students to realize the power of careful data acquisition combined with astute image processing techniques (refer to the video abstract).

Thermally assisted nanosecond laser generation of ferric nanoparticles

NASA Astrophysics Data System (ADS)

Kurselis, K.; Kozheshkurt, V.; Kiyan, R.; Chichkov, B.; Sajti, L.

2018-03-01

A technique to increase nanosecond laser based production of ferric nanoparticles by elevating temperature of the iron target and controlling its surface exposure to oxygen is reported. High power near-infrared laser ablation of the iron target heated up to 600 °C enhances the particle generation efficiency by more than tenfold exceeding 6 μg/J. Temporal and thermal dependencies of the particle generation process indicate correlation of this enhancement with the oxidative processes that take place on the iron surface during the per spot interpulse delay. Nanoparticles, produced using the heat-assisted ablation technique, are examined using scanning electron and transmission electron microscopy confirming the presence of 1-100 nm nanoparticles with an exponential size distribution that contain multiple randomly oriented magnetite nanocrystallites. The described process enables the application of high power lasers and facilitates precise, uniform, and controllable direct deposition of ferric nanoparticle coatings at the industry-relevant rates.

Design of a Low Power, Fast-Spectrum, Liquid-Metal Cooled Surface Reactor System

NASA Astrophysics Data System (ADS)

Marcille, T. F.; Dixon, D. D.; Fischer, G. A.; Doherty, S. P.; Poston, D. I.; Kapernick, R. J.

2006-01-01

In the current 2005 US budget environment, competition for fiscal resources make funding for comprehensive space reactor development programs difficult to justify and accommodate. Simultaneously, the need to develop these systems to provide planetary and deep space-enabling power systems is increasing. Given that environment, designs intended to satisfy reasonable near-term surface missions, using affordable technology-ready materials and processes warrant serious consideration. An initial lunar application design incorporating a stainless structure, 880 K pumped NaK coolant system and a stainless/UO2 fuel system can be designed, fabricated and tested for a fraction of the cost of recent high-profile reactor programs (JIMO, SP-100). Along with the cost reductions associated with the use of qualified materials and processes, this design offers a low-risk, high-reliability implementation associated with mission specific low temperature, low burnup, five year operating lifetime requirements.

Low-power, high-uniform, and forming-free resistive memory based on Mg-deficient amorphous MgO film with rough surface

NASA Astrophysics Data System (ADS)

Guo, Jiajun; Ren, Shuxia; Wu, Liqian; Kang, Xin; Chen, Wei; Zhao, Xu

2018-03-01

Saving energy and reducing operation parameter fluctuations remain crucial for enabling resistive random access memory (RRAM) to emerge as a universal memory. In this work, we report a resistive memory device based on an amorphous MgO (a-MgO) film that not only exhibits ultralow programming voltage (just 0.22 V) and low power consumption (less than 176.7 μW) but also shows excellent operative uniformity (the coefficient of variation is only 1.7% and 2.2% for SET and RESET voltage, respectively). Moreover, it also shows a forming-free characteristic. Further analysis indicates that these distinctive properties can be attributed to the unstable local structures and the rough surface of the Mg-deficient a-MgO film. These findings show the potential of using a-MgO in high-performance nonvolatile memory applications.

LANDSAT-4 image data quality analysis for energy related applications. [nuclear power plant sites

NASA Technical Reports Server (NTRS)

Wukelic, G. E. (Principal Investigator)

1983-01-01

No useable LANDSAT 4 TM data were obtained for the Hanford site in the Columbia Plateau region, but TM simulator data for a Virginia Electric Company nuclear power plant was used to test image processing algorithms. Principal component analyses of this data set clearly indicated that thermal plumes in surface waters used for reactor cooling would be discrenible. Image processing and analysis programs were successfully testing using the 7 band Arkansas test scene and preliminary analysis of TM data for the Savanah River Plant shows that current interactive, image enhancement, analysis and integration techniques can be effectively used for LANDSAT 4 data. Thermal band data appear adequate for gross estimates of thermal changes occurring near operating nuclear facilities especially in surface water bodies being used for reactor cooling purposes. Additional image processing software was written and tested which provides for more rapid and effective analysis of the 7 band TM data.

Application of a simple power law for transport ratio with bimodal distributions of spherical grains under oscillatory forcing

NASA Astrophysics Data System (ADS)

Holway, Kevin; Thaxton, Christopher S.; Calantoni, Joseph

2012-11-01

Morphodynamic models of coastal evolution require relatively simple parameterizations of sediment transport for application over larger scales. Calantoni and Thaxton (2008) [6] presented a transport parameterization for bimodal distributions of coarse quartz grains derived from detailed boundary layer simulations for sheet flow and near sheet flow conditions. The simulation results, valid over a range of wave forcing conditions and large- to small-grain diameter ratios, were successfully parameterized with a simple power law that allows for the prediction of the transport rates of each size fraction. Here, we have applied the simple power law to a two-dimensional cellular automaton to simulate sheet flow transport. Model results are validated with experiments performed in the small oscillating flow tunnel (S-OFT) at the Naval Research Laboratory at Stennis Space Center, MS, in which sheet flow transport was generated with a bed composed of a bimodal distribution of non-cohesive grains. The work presented suggests that, under the conditions specified, algorithms that incorporate the power law may correctly reproduce laboratory bed surface measurements of bimodal sheet flow transport while inherently incorporating vertical mixing by size.

Radiation characteristics of input power from surface wave sustained plasma antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naito, T., E-mail: Naito.Teruki@bc.MitsubishiElectric.co.jp; Yamaura, S.; Fukuma, Y.

This paper reports radiation characteristics of input power from a surface wave sustained plasma antenna investigated theoretically and experimentally, especially focusing on the power consumption balance between the plasma generation and the radiation. The plasma antenna is a dielectric tube filled with argon and small amount of mercury, and the structure is a basic quarter wavelength monopole antenna at 2.45 GHz. Microwave power at 2.45 GHz is supplied to the plasma antenna. The input power is partially consumed to sustain the plasma, and the remaining part is radiated as a signal. The relationship between the antenna gain and the input powermore » is obtained by an analytical derivation and numerical simulations. As a result, the antenna gain is kept at low values, and most of the input power is consumed to increase the plasma volume until the tube is filled with the plasma whose electron density is higher than the critical electron density required for sustaining the surface wave. On the other hand, the input power is consumed to increase the electron density after the tube is fully filled with the plasma, and the antenna gain increases with increasing the electron density. The dependence of the antenna gain on the electron density is the same as that of a plasma antenna sustained by a DC glow discharge. These results are confirmed by experimental results of the antenna gain and radiation patterns. The antenna gain of the plasma is a few dB smaller than that of the identical metal antenna. The antenna gain of the plasma antenna is sufficient for the wireless communication, although it is difficult to substitute the plasma antenna for metal antennas completely. The plasma antenna is suitable for applications having high affinity with the plasma characteristics such as low interference and dynamic controllability.« less

Preliminary Evaluation of Polyarylate Dielectric Films for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammoud, Ahmad; Fialla, Peter

2002-01-01

Polymeric materials are used extensively on spacecraft and satellites in electrical power and distribution systems, as thermal blankets and optical surface coatings, as well as mechanical support structures. The reliability of these systems when exposed to the harsh environment of space is very critical to the success of the mission and the safety of the crew in manned-flight ventures. In this work, polyarylate films were evaluated for potential use as capacitor dielectrics and wiring insulation for cryogenic applications. Two grades of the film were characterized in terms of their electrical and mechanical properties before and after exposure to liquid nitrogen (-196 C). The electrical characterization consisted of capacitance and dielectric loss measure Cents in the frequency range of 50 Hz to 100 kHz, and volume and surface resistivities. The mechanical measurements performed included changes in tensile (Young's modulus, elongation-at-break, and tensile strength) and structural properties (dimensional change, weight, and surface morphology). The preliminary results, which indicate good stability of the polymer after exposure to liquid nitrogen, are presented and discussed.

Space Solar Power Technology Demonstration for Lunar Polar Applications

NASA Technical Reports Server (NTRS)

Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, J.

2002-01-01

A solar power generation station on a mountaintop near the moon's North or South pole can receive sunlight 708 hours per lunar day, for continuous power generation. Power can be beamed from this station over long distances using a laser-based wireless power transmission system and a photo-voltaic receiver. This beamed energy can provide warmth, electricity, and illumination for a robotic rover to perform scientific experiments in cold, dark craters where no other power source is practical. Radio-frequency power transmission may also be demonstrated in lunar polar applications to locate and recover sub-surface deposits of volatile material, such as water ice. High circular polarization ratios observed in data from Clementine spacecraft and Arecibo radar reflections from the moon's South pole suggest that water ice is indeed present in certain lunar polar craters. Data from the Lunar Prospector spacecraft's epi-thermal neutron spectrometer also indicate that hydrogen is present at the moon's poles. Space Solar Power technology enables investigation of these craters, which may contain a billion-year-old stratigraphic record of tremendous scientific value. Layers of ice, preserved at the moon's poles, could help us determine the sequence and composition of comet impacts on the moon. Such ice deposits may even include distinct strata deposited by secondary ejecta following significant Earth (ocean) impacts, linked to major extinctions of life on Earth. Ice resources at the moon's poles could provide water and air for human exploration and development of space as well as rocket propellant for future space transportation. Technologies demonstrated and matured via lunar polar applications can also be used in other NASA science missions (Valles Marineris. Phobos, Deimos, Mercury's poles, asteroids, etc.) and in future large-scale SSP systems to beam energy from space to Earth. Ground-based technology demonstrations are proceeding to mature the technology for such a near-term scientific mission to the moon. This paper reviews the progress to date in demonstrating this technology on Earth and details the plans for near-term applications, to meet NASA's needs, in the moon's polar regions.

Development of a fiber-guided laser ultrasonic system resilient to high temperature and gamma radiation for nuclear power plant pipe monitoring

NASA Astrophysics Data System (ADS)

Yang, Jinyeol; Lee, Hyeonseok; Lim, Hyung Jin; Kim, Nakhyeon; Yeo, Hwasoo; Sohn, Hoon

2013-08-01

This study develops an embeddable optical fiber-guided laser ultrasonic system for structural health monitoring (SHM) of pipelines exposed to high temperature and gamma radiation inside nuclear power plants (NPPs). Recently, noncontact laser ultrasonics is gaining popularity among the SHM community because of its advantageous characteristics such as (a) scanning capability, (b) immunity against electromagnetic interference (EMI) and (c) applicability to high-temperature surfaces. However, its application to NPP pipelines has been hampered because pipes inside NPPs are often covered by insulators and/or target surfaces are not easily accessible. To overcome this problem, this study designs embeddable optical fibers and fixtures so that laser beams used for ultrasonic inspection can be transmitted between the laser sources and the target pipe. For guided-wave generation, an Nd:Yag pulsed laser coupled with an optical fiber is used. A high-power pulsed laser beam is guided through the optical fiber onto a target structure. Based on the principle of laser interferometry, the corresponding response is measured using a different type of laser beam guided by another optical fiber. All devices are especially designed to sustain high temperature and gamma radiation. The robustness/resilience of the proposed measurement system installed on a stainless steel pipe specimen has been experimentally verified by exposing the specimen to high temperature of up to 350 °C and optical fibers to gamma radiation of up to 125 kGy (20 kGy h-1).

High power CO II lasers and their material processing applications at Centre for Advanced Technology, India

NASA Astrophysics Data System (ADS)

Nath, A. K.; Paul, C. P.; Rao, B. T.; Kau, R.; Raghu, T.; Mazumdar, J. Dutta; Dayal, R. K.; Mudali, U. Kamachi; Sastikumar, D.; Gandhi, B. K.

2006-01-01

We have developed high power transverse flow (TF) CW CO II lasers up to 15kW, a high repetition rate TEA CO II laser of 500Hz, 500W average power and a RF excited fast axial flow CO II laser at the Centre for Advanced Technology and have carried out various material processing applications with these lasers. We observed very little variation of discharge voltage with electrode gap in TF CO II lasers. With optimally modulated laser beam we obtained better results in laser piercing and cutting of titanium and resolidification of 3 16L stainless steel weld-metal for improving intergranular corrosion resistance. We carried out microstructure and phase analysis of laser bent 304 stainless steel sheet and optimum process zones were obtained. We carried out laser cladding of 316L stainless steel and Al-alloy substrates with Mo, WC, and Cr IIC 3 powder to improve their wear characteristics. We developed a laser rapid manufacturing facility and fabricated components of various geometries with minimum surface roughness of 5-7 microns Ra and surface waviness of 45 microns between overlapped layers using Colmonoy-6, 3 16L stainless steel and Inconel powders. Cutting of thick concrete blocks by repeated laser glazing followed by mechanical scrubbing process and drilling holes on a vertical concrete with laser beam incident at an optimum angle allowing molten material to flow out under gravity were also done. Some of these studies are briefly presented here.

Investigation of Surface Preparations to Enhance Photon Doppler Velocimetry Measurements

DTIC Science & Technology

2015-08-01

of Angle, Surface Profilometery, and Optical Photography at 10-, 20-, and 40-Times Magnifications 53 Appendix J. Kevlar Reflected Power... applicability to measure many velocities that the Army is interested in: floor accelerations due to an under- vehicle mine blast;4 material deformations from...x … x F HB-26 x … … … … x … x G Al2O3 x … … … … … … … H Polyethylene x … … … … x … … I Kevlar x … … … … … … x J Mild Steel … … … … … x

Surface Interaction of Bent-Core Liquid Crystals "Slipping on a Banana Peel"

NASA Astrophysics Data System (ADS)

Iglesias Gonzalez, Wilder G.

The main emphasis and focus of this talk revolves around liquid crystalline molecules with frustrated symmetry, molecules with a kink in the core resembling the shape of a banana. These novel materials are not only suitable and interesting for the common liquid crystal display field as fast switching candidates, but for a whole wide range of potential applications, such as: power generation, microscale actuators, optical storage devices, to name a few. Understanding surface interactions of these mesogens is a key factor in controlling and unveiling the vast potential capabilities of such liquid crystals.

Solid Lubrication Fundamentals and Applications. Chapter 2

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1998-01-01

This chapter describes powerful analytical techniques capable of sampling tribological surfaces and solid-film lubricants. Some of these techniques may also be used to determine the locus of failure in a bonded structure or coated substrate; such information is important when seeking improved adhesion between a solid-film lubricant and a substrate and when seeking improved performance and long life expectancy of solid lubricants. Many examples are given here and through-out the book on the nature and character of solid surfaces and their significance in lubrication, friction, and wear. The analytical techniques used include the late spectroscopic methods.

Measurements of print-through in graphite fiber epoxy composites

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Jeunnette, Timothy T.; Anzic, Judith M.

1989-01-01

High-reflectance accurate-contour mirrors are needed for solar dynamic space power systems. Graphite fiber epoxy composites are attractive candidates for such applications owing to their high modulus, near-zero coefficient of thermal expansion, and low mass. However, mirrors prepared from graphite fiber epoxy composite substrates often exhibit print-through, a distortion of the surface, which causes a loss in solar specular reflectance. Efforts to develop mirror substrates without print-through distortion require a means of quantifying print-through. Methods have been developed to quantify the degree of print-through in graphite fiber epoxy composite specimens using surface profilometry.

Oscillatory supersonic kernel function method for interfering surfaces

NASA Technical Reports Server (NTRS)

Cunningham, A. M., Jr.

1974-01-01

In the method presented in this paper, a collocation technique is used with the nonplanar supersonic kernel function to solve multiple lifting surface problems with interference in steady or oscillatory flow. The pressure functions used are based on conical flow theory solutions and provide faster solution convergence than is possible with conventional functions. In the application of the nonplanar supersonic kernel function, an improper integral of a 3/2 power singularity along the Mach hyperbola is described and treated. The method is compared with other theories and experiment for two wing-tail configurations in steady and oscillatory flow.

Design, fabrication, and testing of duralumin zoom mirror with variable thickness

NASA Astrophysics Data System (ADS)

Hui, Zhao; Xie, Xiaopeng; Xu, Liang; Ding, Jiaoteng; Shen, Le; Liu, Meiying; Gong, Jie

2016-10-01

Zoom mirror is a kind of active optical component that can change its curvature radius dynamically. Normally, zoom mirror is used to correct the defocus and spherical aberration caused by thermal lens effect to improve the beam quality of high power solid-state laser since that component was invented. Recently, the probable application of zoom mirror in realizing non-moving element optical zoom imaging in visible band has been paid much attention. With the help of optical leveraging effect, the slightly changed local optical power caused by curvature variation of zoom mirror could be amplified to generate a great alteration of system focal length without moving elements involved in, but in this application the shorter working wavelength and higher surface figure accuracy requirement make the design and fabrication of such a zoom mirror more difficult. Therefore, the key to realize non-moving element optical zoom imaging in visible band lies in zoom mirror which could provide a large enough saggitus variation while still maintaining a high enough surface figure. Although the annular force based actuation could deform a super-thin mirror having a constant thickness to generate curvature variation, it is quite difficult to maintain a high enough surface figure accuracy and this phenomenon becomes even worse when the diameter and the radius-thickness ratio become bigger. In this manuscript, by combing the pressurization based actuation with a variable thickness mirror design, the purpose of obtaining large saggitus variation and maintaining quite good surface figure accuracy at the same time could be achieved. A prototype zoom mirror with diameter of 120mm and central thickness of 8mm is designed, fabricated and tested. Experimental results demonstrate that the zoom mirror having an initial surface figure accuracy superior to 1/50λ could provide at least 21um saggitus variation and after finishing the curvature variation its surface figure accuracy could still be superior to 1/20λ, which proves that the effectiveness of the theoretical design.

Material Processing Opportunites Utilizing a Free Electron Laser

NASA Astrophysics Data System (ADS)

Todd, Alan

1996-11-01

Many properties of photocathode-driven Free Electron Lasers (FEL) are extremely attractive for material processing applications. These include: 1) broad-band tunability across the IR and UV spectra which permits wavelength optimization, depth deposition control and utilization of resonance phenomena; 2) picosecond pulse structure with continuous nanosecond spacing for optimum deposition efficiency and minimal collateral damage; 3) high peak and average radiated power for economic processing in quantity; and 4) high brightness for spatially defined energy deposition and intense energy density in small spots. We discuss five areas: polymer, metal and electronic material processing, micromachining and defense applications; where IR or UV material processing will find application if the economics is favorable. Specific examples in the IR and UV, such as surface texturing of polymers for improved look and feel, and anti-microbial food packaging films, which have been demonstrated using UV excimer lamps and lasers, will be given. Unfortunately, although the process utility is readily proven, the power levels and costs of lamps and lasers do not scale to production margins. However, from these examples, application specific cost targets ranging from 0.1=A2/kJ to 10=A2/kJ of delivered radiation at power levels from 10 kW to 500 kW, have been developed and are used to define strawman FEL processing systems. Since =46EL radiation energy extraction from the generating electron beam is typically a few percent, at these high average power levels, economic considerations dictate the use of a superconducting RF accelerator with energy recovery to minimize cavity and beam dump power loss. Such a 1 kW IR FEL, funded by the US Navy, is presently under construction at the Thomas Jefferson National Accelerator Facility. This dual-use device, scheduled to generate first light in late 1997, will test both the viability of high-power FELs for shipboard self-defense against cruise missiles, and for the first time, provide an industrial testbed capable of processing various materials in market evaluation quantities.

Options for Affordable Fission Surface Power Systems

NASA Technical Reports Server (NTRS)

Houts, Mike; Gaddis, Steve; Porter, Ron; VanDyke, Melissa; Martin Jim; Godfroy, Tom; Bragg-Sitton, Shannon; Garber, Anne; Pearson, Boise

2006-01-01

Fission surface power systems could provide abundant power anywhere on free surface of the moon or Mars. Locations could include permanently shaded regions on the moon and high latitudes on Mars. To be fully utilized; however, fission surface power systems must be safe, have adequate performance, and be affordable. This paper discusses options for the design and development of such systems.

Microfabrication of microchannels for fuel cell plates.

PubMed

Jang, Ho Su; Park, Dong Sam

2010-01-01

Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

Microfabrication of Microchannels for Fuel Cell Plates

PubMed Central

Jang, Ho Su; Park, Dong Sam

2010-01-01

Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating. PMID:22315533

Kinetic Monte Carlo simulations of GaN homoepitaxy on c- and m-plane surfaces

DOE PAGES

Xu, Dongwei; Zapol, Peter; Stephenson, G. Brian; ...

2017-04-12

The surface orientation can have profound effects on the atomic-scale processes of crystal growth and is essential to such technologies as GaN-based light-emitting diodes and high-power electronics. We investigate the dependence of homoepitaxial growth mechanisms on the surface orientation of a hexagonal crystal using kinetic Monte Carlo simulations. To model GaN metal-organic vapor phase epitaxy, in which N species are supplied in excess, only Ga atoms on a hexagonal close-packed (HCP) lattice are considered. The results are thus potentially applicable to any HCP material. Growth behaviors on c-plane (0001) and m-plane (011¯0) surfaces are compared. We present a reciprocal spacemore » analysis of the surface morphology, which allows extraction of growth mode boundaries and direct comparison with surface X-ray diffraction experiments. For each orientation, we map the boundaries between 3-dimensional, layer-by-layer, and step flow growth modes as a function of temperature and growth rate. Two models for surface diffusion are used, which produce different effective Ehrlich-Schwoebel step-edge barriers and different adatom diffusion anisotropies on m-plane surfaces. Simulation results in agreement with observed GaN island morphologies and growth mode boundaries are obtained. These indicate that anisotropy of step edge energy, rather than adatom diffusion, is responsible for the elongated islands observed on m-plane surfaces. As a result, island nucleation spacing obeys a power-law dependence on growth rate, with exponents of –0.24 and –0.29 for the m- and c-plane, respectively.« less

Kinetic Monte Carlo simulations of GaN homoepitaxy on c- and m-plane surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Dongwei; Zapol, Peter; Stephenson, G. Brian

The surface orientation can have profound effects on the atomic-scale processes of crystal growth and is essential to such technologies as GaN-based light-emitting diodes and high-power electronics. We investigate the dependence of homoepitaxial growth mechanisms on the surface orientation of a hexagonal crystal using kinetic Monte Carlo simulations. To model GaN metal-organic vapor phase epitaxy, in which N species are supplied in excess, only Ga atoms on a hexagonal close-packed (HCP) lattice are considered. The results are thus potentially applicable to any HCP material. Growth behaviors on c-plane (0001) and m-plane (011¯0) surfaces are compared. We present a reciprocal spacemore » analysis of the surface morphology, which allows extraction of growth mode boundaries and direct comparison with surface X-ray diffraction experiments. For each orientation, we map the boundaries between 3-dimensional, layer-by-layer, and step flow growth modes as a function of temperature and growth rate. Two models for surface diffusion are used, which produce different effective Ehrlich-Schwoebel step-edge barriers and different adatom diffusion anisotropies on m-plane surfaces. Simulation results in agreement with observed GaN island morphologies and growth mode boundaries are obtained. These indicate that anisotropy of step edge energy, rather than adatom diffusion, is responsible for the elongated islands observed on m-plane surfaces. As a result, island nucleation spacing obeys a power-law dependence on growth rate, with exponents of –0.24 and –0.29 for the m- and c-plane, respectively.« less

Theoretical limits of the multistacked 1D and 2D microstructured inorganic solar cells

NASA Astrophysics Data System (ADS)

Yengel, Emre; Karaagac, Hakan; VJ, Logeeswaran; Islam, M. Saif

2015-09-01

Recent studies in monocrystalline semiconductor solar cells are focused on mechanically stacking multiple cells from different materials to increase the power conversion efficiency. Although, the results show promising increase in the device performance, the cost remains as the main drawback. In this study, we calculated the theoretical limits of multistacked 1D and 2D microstructered inorganic monocrstalline solar cells. This system is studied for Si and Ge material pair. The results show promising improvements in the surface reflection due to enhanced light trapping caused by photon-microstructures interactions. The theoretical results are also supported with surface reflection and angular dependent power conversion efficiency measurements of 2D axial microwall solar cells. We address the challenge of cost reduction by proposing to use our recently reported mass-manufacturable fracture-transfer- printing method which enables the use of a monocrystalline substrate wafer for repeated fabrication of devices by consuming only few microns of materials in each layer of devices. We calculated thickness dependent power conversion efficiencies of multistacked Si/Ge microstructured solar cells and found the power conversion efficiency to saturate at 26% with a combined device thickness of 30 μm. Besides having benefits of fabricating low-cost, light weight, flexible, semi-transparent, and highly efficient devices, the proposed fabrication method is applicable for other III-V materials and compounds to further increase the power conversion efficiency above 35% range.

Optical fiber designs for beam shaping

NASA Astrophysics Data System (ADS)

Farley, Kevin; Conroy, Michael; Wang, Chih-Hao; Abramczyk, Jaroslaw; Campbell, Stuart; Oulundsen, George; Tankala, Kanishka

2014-03-01

A large number of power delivery applications for optical fibers require beams with very specific output intensity profiles; in particular applications that require a focused high intensity beam typically image the near field (NF) intensity distribution at the exit surface of an optical fiber. In this work we discuss optical fiber designs that shape the output beam profile to more closely correspond to what is required in many real world industrial applications. Specifically we present results demonstrating the ability to transform Gaussian beams to shapes required for industrial applications and how that relates to system parameters such as beam product parameter (BPP) values. We report on the how different waveguide structures perform in the NF and show results on how to achieve flat-top with circular outputs.

Deaggregation, Modification, and Developing Applications for Detonation Nanodiamond

NASA Astrophysics Data System (ADS)

Mochalin, Vadym

2017-06-01

Nanodiamond powder (ND) is one of the most promising materials for advanced composites and biomedical applications. It is also a commercial precursor for carbon nanoonions - material for high power micrometer size supercapacitors and potentially, Li-ion batteries. ND is produced by detonation of explosives with negative oxygen balance in a closed chamber, where extremely high pressures and temperatures develop during detonation. ND consists of diamond particles of 5 nm diameter, combining fully accessible large surface and rich and tailorable surface chemistry. ND has unique properties including optical, electrical, thermal, and mechanical, and is biocompatible and non-toxic. Due to numerous surface functional groups, ND has catalytic and electrochemical activity. Several techniques have been proposed for ND deaggregation based on milling with costly ceramic microbeads, leaving difficult to remove contaminations in the resulting ND suspension. We have recently discovered a novel, green technique for ND deaggregation using sonication in aqueous sodium chloride slurry. Upon completion of the process sodium chloride can be easily washed out with water leaving behind no contaminants and yielding stable single-digit ND colloids. Modification and development of applications for ND in composites, drug delivery, biomedical imaging, etc., will be also discussed.

Fundamentals and applications of SERS-based bioanalytical sensing

NASA Astrophysics Data System (ADS)

Kahraman, Mehmet; Mullen, Emma R.; Korkmaz, Aysun; Wachsmann-Hogiu, Sebastian

2017-03-01

Plasmonics is an emerging field that examines the interaction between light and metallic nanostructures at the metal-dielectric interface. Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that uses plasmonics to obtain detailed chemical information of molecules or molecular assemblies adsorbed or attached to nanostructured metallic surfaces. For bioanalytical applications, these surfaces are engineered to optimize for high enhancement factors and molecular specificity. In this review we focus on the fabrication of SERS substrates and their use for bioanalytical applications. We review the fundamental mechanisms of SERS and parameters governing SERS enhancement. We also discuss developments in the field of novel SERS substrates. This includes the use of different materials, sizes, shapes, and architectures to achieve high sensitivity and specificity as well as tunability or flexibility. Different fundamental approaches are discussed, such as label-free and functional assays. In addition, we highlight recent relevant advances for bioanalytical SERS applied to small molecules, proteins, DNA, and biologically relevant nanoparticles. Subsequently, we discuss the importance of data analysis and signal detection schemes to achieve smaller instruments with low cost for SERS-based point-of-care technology developments. Finally, we review the main advantages and challenges of SERS-based biosensing and provide a brief outlook.

Indoor air purification by dielectric barrier discharge combined with ionic wind: physical and microbiological investigations

NASA Astrophysics Data System (ADS)

Timmermann, E.; Prehn, F.; Schmidt, M.; Höft, H.; Brandenburg, R.; Kettlitz, M.

2018-04-01

A non-thermal plasma source based on a surface dielectric barrier discharge (DBD) is developed for purification of recirculating air in operating theatres in hospitals. This is a challenging application due to high flow rates, short treatment times and the low threshold for ozone in the ventilated air. Therefore, the surface DBD was enhanced in order to generate an ionic wind, which can deflect and thus, filter out airborne microorganisms. Electrical and gas diagnostics as well as microbiological experiments were performed in a downscaled plasma source under variation of various electrical parameters, but application-oriented airflow velocity and humidity. The dependence of electrical power and ozone concentration as well as charged particles in the plasma treated air on frequency, voltage and relative humidity is presented and discussed. The presence of humidity causes a more conductive dielectric surface and thus a weaker plasma formation, especially at low frequency. The airborne test bacteria, Escherichia coli, showed significant effect to plasma treatment (up to 20% reduction) and to plasma with ionic wind (up to 90% removal); especially a configuration with 70% removal and an accompanying ozone concentration of only 360 ppb is promising for future application.

Electrostatic force microscopy as a broadly applicable method for characterizing pyroelectric materials.

PubMed

Martin-Olmos, Cristina; Stieg, Adam Z; Gimzewski, James K

2012-06-15

A general method based on the combination of electrostatic force microscopy with thermal cycling of the substrate holder is presented for direct, nanoscale characterization of the pyroelectric effect in a range of materials and sample configurations using commercial atomic force microscope systems. To provide an example of its broad applicability, the technique was applied to the examination of natural tourmaline gemstones. The method was validated using thermal cycles similar to those experienced in ambient conditions, where the induced pyroelectric response produced localized electrostatic surface charges whose magnitude demonstrated a correlation with the iron content and heat dissipation of each gemstone variety. In addition, the surface charge was shown to persist even at thermal equilibrium. This behavior is attributed to constant, stochastic cooling of the gemstone surface through turbulent contact with the surrounding air and indicates a potential utility for energy harvesting in applications including environmental sensors and personal electronics. In contrast to previously reported methods, ours has a capacity to carry out such precise nanoscale measurements with little or no restriction on the sample of interest, and represents a powerful new tool for the characterization of pyroelectric materials and devices.

Electrostatic force microscopy as a broadly applicable method for characterizing pyroelectric materials

NASA Astrophysics Data System (ADS)

Martin-Olmos, Cristina; Stieg, Adam Z.; Gimzewski, James K.

2012-06-01

A general method based on the combination of electrostatic force microscopy with thermal cycling of the substrate holder is presented for direct, nanoscale characterization of the pyroelectric effect in a range of materials and sample configurations using commercial atomic force microscope systems. To provide an example of its broad applicability, the technique was applied to the examination of natural tourmaline gemstones. The method was validated using thermal cycles similar to those experienced in ambient conditions, where the induced pyroelectric response produced localized electrostatic surface charges whose magnitude demonstrated a correlation with the iron content and heat dissipation of each gemstone variety. In addition, the surface charge was shown to persist even at thermal equilibrium. This behavior is attributed to constant, stochastic cooling of the gemstone surface through turbulent contact with the surrounding air and indicates a potential utility for energy harvesting in applications including environmental sensors and personal electronics. In contrast to previously reported methods, ours has a capacity to carry out such precise nanoscale measurements with little or no restriction on the sample of interest, and represents a powerful new tool for the characterization of pyroelectric materials and devices.

Parameters for Efficient Fuel Cell Catalyst Structures

DTIC Science & Technology

2011-04-03

investigation of Pd towards the MOR was therefore not investigated in detail. 3.4 Pt on Diamond Pt nanostructured monocrystalline diamond(100...potentiostatic double pulse technique. Monocrystalline diamond is particularly suitable for this application due to the homogeneous surface and the...Henglein, U. Stimming, and W. Unkauf, Electrochim. Acta, 45, (2000) 3283. [4] H. A. Gasteiger, J. E. Panels , and S. G. Yan, J. Power Sources, 127

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications

DOEpatents

Tam, S.W.

1998-06-16

An illumination source is disclosed comprising a porous silicon having a source of electrons on the surface and/or interstices thereof having a total porosity in the range of from about 50 v/o to about 90 v/o. Also disclosed are a tritiated porous silicon and a photovoltaic device and an illumination source of tritiated porous silicon. 1 fig.

Porous silicon with embedded tritium as a stand-alone prime power source for optoelectronic applications

DOEpatents

Tam, S.W.

1997-02-25

Disclosed is an illumination source comprising a porous silicon having a source of electrons on the surface and/or interstices thereof having a total porosity in the range of from about 50 v/o to about 90 v/o. Also disclosed are a tritiated porous silicon and a photovoltaic device and an illumination source of tritiated porous silicon. 1 fig.

75 FR 75996 - Kahawai Power 2, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-07

...: (1) A proposed 6-foot-high and 40-foot-long reinforced concrete weir and intake structure on the... and 40-foot-long reinforced concrete weir and intake structure on the Mokuone stream that will maintain a normal surface elevation of 2,200 feet msl; (3) a new 31,000-foot-long, steel penstock; (4) a...

Few layered vanadyl phosphate nano sheets-MWCNT hybrid as an electrode material for supercapacitor application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, Shibsankar; De, Sukanta, E-mail: sukanta.physics@presiuniv.ac.in

It have been already seen that 2-dimensional nano materials are the suitable choice for the supercapacitor application due to their large specific surface area, electrochemical active sites, micromechanical flexibility, expedite ion migration channel properties. Free standing hybrid films of functionalized MWCNT (– COOH group) and α-Vanadyl phosphates (VOPO{sub 4}2H{sub 2}O) are prepared by vacuum filtering. The surface morphology and microstructure of the samples are studied by transmission electron microscope, field emission scanning electron microscope, XRD, Electrochemical properties of hybrid films have been investigated systematically in 1M Na{sub 2}SO{sub 4} aqueous electrolyte. The hybrid material exhibits a high specific capacitance 236more » F/g with high energy density of 65.6 Wh/Kg and a power density of 1476 W/Kg.« less

Color-coded multilayer photopatterned microstructures using lanthanide (III) ion co-doped NaYF4 nanoparticles with upconversion luminescence for possible applications in security.

PubMed

Kim, Won Jin; Nyk, Marcin; Prasad, Paras N

2009-05-06

We report a method for fabricating predefined photopatterns of upconversion nanophosphors using a chemical amplification reaction for direct writing of films with multilayer color-coded patterning for security applications. To photopattern the nanocrystal film we have synthesized rare-earth ion (Er(3+)/Yb(3+) or Tm(3+)/Yb(3+)) co-doped sodium yttrium fluoride (alpha-NaYF(4)) nanophosphors and functionalized the nanocrystal surfaces by incorporation of a photopatternable ligand such as t-butoxycarbonyl (t-BOC). The surface modification allows photopatterning of the nanophosphor solid state film. Furthermore, upconversion nanophosphors show a nearly quadratic dependence of the upconversion photoluminescence (PL) intensity on the excitation light power, and tailoring of the PL wavelength is possible by changing the lanthanide ions. We have demonstrated the capability of anchoring nanophosphors at desirable locations by a photolithography technique. The photopatterned films exhibit fixed nanophosphor structures clearly identifiable by strong upconversion photoluminescence under IR illumination which is useful for a number of applications in security.

Laser beam temporal and spatial tailoring for laser shock processing

DOEpatents

Hackel, Lloyd; Dane, C. Brent

2001-01-01

Techniques are provided for formatting laser pulse spatial shape and for effectively and efficiently delivering the laser energy to a work surface in the laser shock process. An appropriately formatted pulse helps to eliminate breakdown and generate uniform shocks. The invention uses a high power laser technology capable of meeting the laser requirements for a high throughput process, that is, a laser which can treat many square centimeters of surface area per second. The shock process has a broad range of applications, especially in the aerospace industry, where treating parts to reduce or eliminate corrosion failure is very important. The invention may be used for treating metal components to improve strength and corrosion resistance. The invention has a broad range of applications for parts that are currently shot peened and/or require peening by means other than shot peening. Major applications for the invention are in the automotive and aerospace industries for components such as turbine blades, compressor components, gears, etc.

Lunar electric power systems utilizing the SP-100 reactor coupled to dynamic conversion systems

NASA Technical Reports Server (NTRS)

Harty, Richard B.; Durand, Richard E.

1993-01-01

An integration study was performed by Rocketdyne under contract to NASA-LeRC. The study was concerned with coupling an SP-0100 reactor to either a Brayton or Stirling power conversion system. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum power conversion redundancy. This study resulted in selecting three operating engines and one stand-by unit. Integration design studies indicated that either the Brayton or Stirling power conversion systems could be integrated with the PS-100 reactor. The Stirling system had an integration advantage because of smaller piping size and fewer components. The Stirling engine, however, is more complex and heavier than the Brayton rotating unit, which tends to off-set the Stirling integration advantage. From a performance consideration, the Brayton had a 9 percent mass advantage, and the Stirling had a 50 percent radiator advantage.

Radioisotope Heater Unit-Based Stirling Power Convertor Development at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Wilson, Scott D.; Geng, Steven M.; Penswick, Lawrence; Schmitz, Paul C.

2017-01-01

Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A variety of mission concepts have been studied by NASA and the U. S. Department of Energy that would utilize RPS for landers, probes, and rovers and only require milliwatts to tens of watts of power. These missions would contain science measuring instruments that could be distributed across planetary surfaces or near objects of interest in space solar flux insufficient for using solar cells. A low power Stirling convertor is being developed to provide an RPS option for future low power applications. Initial concepts convert heat available from several Radioisotope Heater Units to electrical power for spacecraft instruments and communication. Initial development activity includes defining and evaluating a variety of Stirling configurations and selecting one for detailed design, research of advanced manufacturing methods that could simplify fabrication, evaluating thermal interfaces, characterizing components and subassemblies to validate design codes, and preparing for an upcoming demonstration of proof of concept in a laboratory environment.

Micro-sensors for in-situ meteorological measurements

NASA Technical Reports Server (NTRS)

Crisp, David; Kaiser, William J.; Vanzandt, Thomas R.; Tillman, James E.

1993-01-01

Improved in-situ meteorological measurements are needed for monitoring the weather and climate of the terrestrial and Martian atmospheres. We have initiated a program to assess the feasibility and utility of micro-sensors for precise in-situ meteorological measurements in these environments. Sensors are being developed for measuring pressure, temperature, wind velocity, humidity, and aerosol amounts. Silicon micro-machining and large scale integration technologies are being used to make sensors that are small, rugged, lightweight, and require very little power. Our long-term goal is to develop very accurate miniaturized sensors that can be incorporated into complete instrument packages or 'micro weather stations,' and deployed on a variety of platforms. If conventional commercially available silicon production techniques can be used to fabricate these sensor packages, it will eventually be possible to mass-produce them at low cost. For studies of the Earth's troposphere and stratosphere, they could be deployed on aircraft, dropsondes, radiosondes, or autonomous surface stations at remote sites. Improved sensor accuracy and reduced sensor cost are the primary challenges for these applications. For studies of the Martian atmosphere, these sensor packages could be incorporated into the small entry probes and surface landers that are being planned for the Mars Environmental SURvey (MESUR) Mission. That decade-long program will deploy a global network of small stations on the Martian surface for monitoring meteorological and geological processes. Low mass, low power, durability, large dynamic range and calibration stability are the principal challenges for this application. Our progress on each of these sensor types is presented.

Rayleigh surface acoustic wave as an efficient heating system for biological reactions: investigation of microdroplet temperature uniformity.

PubMed

Roux-Marchand, Thibaut; Beyssen, Denis; Sarry, Frederic; Elmazria, Omar

2015-04-01

When a microdroplet is put on the Rayleigh surface acoustic wave path, longitudinal waves are radiated into the liquid and induce several phenomena such as the wellknown surface acoustic wave streaming. At the same time, the temperature of the microdroplet increases as it has been shown. In this paper, we study the temperature uniformity of a microdroplet heated by Rayleigh surface acoustic wave for discrete microfluidic applications such as biological reactions. To precisely ascertain the temperature uniformity and not interfere with the biological reaction, we used an infrared camera. We then tested the temperature uniformity as a function of three parameters: the microdroplet volume, the Rayleigh surface acoustic wave frequency, and the continuous applied radio frequency power. Based on these results, we propose a new device structure to develop a future lab on a chip based on reaction temperatures.

TeO2 slow surface acoustic wave Bragg cell

NASA Astrophysics Data System (ADS)

Yao, Shi-Kay

1991-08-01

A newly discovered slow acoustic surface wave (SAW) on a (-110) cut TeO2 surface is reported focusing on its properties studied using a PC based numerical method. It is concluded that the slow SAW is rather tolerant to crystal surface orientation errors and has unusually deep penetration of its shear component into the thickness of substrate, about 47 wavelengths for a half amplitude point. The deep shear field is considered to be beneficial for surface acoustooptic interaction with free propagating focused laser beams. Rotation of the substrate about the z-axis makes it possible to adjust a slow SAW velocity with the potential advantage of trading acoustic velocity for less acoustic attenuation. Wider-bandwidth long signal processing time Bragg cells may be feasible utilizing this trade-off. The slow SAW device is characterized by an extremely low power consumption which might be useful for compact portable or avionics signal processing equipment applications.

Imprint control of BaTiO 3 thin films via chemically induced surface polarization pinning

DOE PAGES

Lee, Hyungwoo; Kim, Tae Heon; Patzner, Jacob J.; ...

2016-02-22

Surface-adsorbed polar molecules can significantly alter the ferroelectric properties of oxide thin films. Thus, fundamental understanding and controlling the effect of surface adsorbates are crucial for the implementation of ferroelectric thin film devices, such as ferroelectric tunnel junctions. Herein, we report an imprint control of BaTiO 3 (BTO) thin films by chemically induced surface polarization pinning in the top few atomic layers of the water-exposed BTO films. Our studies based on synchrotron X-ray scattering and coherent Bragg rod analysis demonstrate that the chemically induced surface polarization is not switchable but reduces the polarization imprint and improves the bistability of ferroelectricmore » phase in BTO tunnel junctions. Here, we conclude that the chemical treatment of ferroelectric thin films with polar molecules may serve as a simple yet powerful strategy to enhance functional properties of ferroelectric tunnel junctions for their practical applications.« less

Selected papers from the 12th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2012) (Atlanta, GA, USA, 2-5 December 2012)

NASA Astrophysics Data System (ADS)

Allen, Mark G.; Lang, Jeffrey

2013-11-01

Welcome to this special section of the Journal of Micromechanics and Microengineering (JMM). This section, co-edited by myself and by Professor Jeffrey Lang of the Massachusetts Institute of Technology, contains expanded versions of selected papers presented at the Power MEMS meeting held in Atlanta, GA, USA, in December of 2012. Professor Lang and I had the privilege of co-chairing Power MEMS 2012, the 12th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications. The scope of the PowerMEMS series of workshops ranges from basic principles, to materials and fabrication, to devices and systems, to applications. The many applications of power MEMS (microelectromehcanical systems) range from MEMS-enabled energy harvesting, storage, conversion and conditioning, to integrated systems that manage these processes. Why is the power MEMS field growing in importance? Smaller-scale power and power supplies (microwatts to tens of watts) are gaining in prominence due to many factors, including the ubiquity of low power portable electronic equipment and the proliferation of wireless sensor nodes that require extraction of energy from their embedding environment in order to function. MEMS manufacturing methods can be utilized to improve the performance of traditional power supply elements, such as allowing batteries to charge faster or shrinking the physical size of passive elements in small-scale power supplies. MEMS technologies can be used to fabricate energy harvesters that extract energy from an embedding environment to power wireless sensor nodes, in-body medical implants and other devices, in which the harvesters are on the small scales that are appropriately matched to the overall size of these microsystems. MEMS can enable the manufacturing of energy storage elements from nontraditional materials by bringing appropriate structure and surface morphology to these materials as well as fabricating the electrical interfaces required for their operation and interconnection. Clearly, the marriage of MEMS technologies and energy conversion is a vital application space; and we are pleased to bring you some of the latest results from that space in this special section. Approximately 130 papers were presented at the Power MEMS 2012 conference. From these, the 20 papers you have before you were selected based on paper quality and topical balance. As you can see, papers representing many of the important areas of power MEMS are included: energy harvesters using multiple transduction schemes; MEMS-based fabrication of compact passive elements (inductors, supercapacitors, transformers); MEMS-enabled power diagnostics; MEMS-based batteries; and low power circuitry adapted to interfacing MEMS-based harvesters to overall systems. All of the papers you will read in this special section comprise substantial expansion from the proceedings articles and were reviewed through JMM's normal reviewing process. Both Professor Lang and I hope that you will share our enthusiasm for the field of power MEMS and that you will find this special section of JMM exciting, interesting and useful.  Sincerely,  Mark G Allen

Case Studies for the Statistical Design of Experiments Applied to Powered Rotor Wind Tunnel Tests

NASA Technical Reports Server (NTRS)

Overmeyer, Austin D.; Tanner, Philip E.; Martin, Preston B.; Commo, Sean A.

2015-01-01

The application of statistical Design of Experiments (DOE) to helicopter wind tunnel testing was explored during two powered rotor wind tunnel entries during the summers of 2012 and 2013. These tests were performed jointly by the U.S. Army Aviation Development Directorate Joint Research Program Office and NASA Rotary Wing Project Office, currently the Revolutionary Vertical Lift Project, at NASA Langley Research Center located in Hampton, Virginia. Both entries were conducted in the 14- by 22-Foot Subsonic Tunnel with a small portion of the overall tests devoted to developing case studies of the DOE approach as it applies to powered rotor testing. A 16-47 times reduction in the number of data points required was estimated by comparing the DOE approach to conventional testing methods. The average error for the DOE surface response model for the OH-58F test was 0.95 percent and 4.06 percent for drag and download, respectively. The DOE surface response model of the Active Flow Control test captured the drag within 4.1 percent of measured data. The operational differences between the two testing approaches are identified, but did not prevent the safe operation of the powered rotor model throughout the DOE test matrices.

The Separation of Blood Components Using Standing Surface Acoustic Waves (SSAWs) Microfluidic Devices: Analysis and Simulation.

PubMed

Soliman, Ahmed M; Eldosoky, Mohamed A; Taha, Taha E

2017-03-29

The separation of blood components (WBCs, RBCs, and platelets) is important for medical applications. Recently, standing surface acoustic wave (SSAW) microfluidic devices are used for the separation of particles. In this paper, the design analysis of SSAW microfluidics is presented. Also, the analysis of SSAW force with Rayleigh angle effect and its attenuation in liquid-loaded substrate, viscous drag force, hydrodynamic force, and diffusion force are explained and analyzed. The analyses are provided for selecting the piezoelectric material, width of the main microchannel, working area of SAW, wavelength, minimum input power required for the separation process, and widths of outlet collecting microchannels. The design analysis of SSAW microfluidics is provided for determining the minimum input power required for the separation process with appropriated the displacement contrast of the particles.The analyses are applied for simulation the separation of blood components. The piezoelectric material, width of the main microchannel, working area of SAW, wavelength, and minimum input power required for the separation process are selected as LiNbO₃, 120 μm, 1.08 mm², 300 μm, 371 mW. The results are compared to other published results. The results of these simulations achieve minimum power consumption, less complicated setup, and high collecting efficiency. All simulation programs are built by MATLAB.

The Separation of Blood Components Using Standing Surface Acoustic Waves (SSAWs) Microfluidic Devices: Analysis and Simulation

PubMed Central

Soliman, Ahmed M.; Eldosoky, Mohamed A.; Taha, Taha E.

2017-01-01

The separation of blood components (WBCs, RBCs, and platelets) is important for medical applications. Recently, standing surface acoustic wave (SSAW) microfluidic devices are used for the separation of particles. In this paper, the design analysis of SSAW microfluidics is presented. Also, the analysis of SSAW force with Rayleigh angle effect and its attenuation in liquid-loaded substrate, viscous drag force, hydrodynamic force, and diffusion force are explained and analyzed. The analyses are provided for selecting the piezoelectric material, width of the main microchannel, working area of SAW, wavelength, minimum input power required for the separation process, and widths of outlet collecting microchannels. The design analysis of SSAW microfluidics is provided for determining the minimum input power required for the separation process with appropriated the displacement contrast of the particles.The analyses are applied for simulation the separation of blood components. The piezoelectric material, width of the main microchannel, working area of SAW, wavelength, and minimum input power required for the separation process are selected as LiNbO3, 120 μm, 1.08 mm2, 300 μm, 371 mW. The results are compared to other published results. The results of these simulations achieve minimum power consumption, less complicated setup, and high collecting efficiency. All simulation programs are built by MATLAB. PMID:28952506

The power of power: electrokinetic control of PAH interactions with exfoliated graphite.

PubMed

Qin, Jinyi; Moustafa, Ahmed; Harms, Hauke; El-Din, Mohamed Gamal; Wick, Lukas Y

2015-05-15

Exfoliated graphite (EG) exhibits exceptional sorption capacity for petroleum and dissolved hydrocarbons owing to its highly hydrophobic surface and wide pore size distribution. The high price of preparing EG, however, restricts its application. Methods which increase the rate or extent of sorption to EG even further are thus longed for. Here, we assess the effects of weak direct current (DC) fields on the sorption of the polycyclic aromatic hydrocarbon phenanthrene (PHE) to EG. DC applied to an ionic solution in a solid matrix invokes electroosmotic flow (EOF), i.e., the surface charge-induced movement of the solution. EG was exposed to weak DC fields in the presence of dissolved PHE to test if EOF increases transport of PHE to poorly accessible sorption sites. DC fields increased PHE sorption rates in EG sevenfold and reduced the desorption rate of sorbed PHE by >99%. EOF thus appeared to be highly effective in translocating PHE into pores, which contribute most of the sorption sites, but are difficult to access in the absence of EOF by molecular diffusion only. The observed 'power of power' may be used to kinetically regulate the interaction of sorbates with EG or other porous sorbents in environmental (bio-) technology. Copyright © 2015 Elsevier B.V. All rights reserved.

Organic transistors manufactured using inkjet technology with subfemtoliter accuracy

PubMed Central

Sekitani, Tsuyoshi; Noguchi, Yoshiaki; Zschieschang, Ute; Klauk, Hagen; Someya, Takao

2008-01-01

A major obstacle to the development of organic transistors for large-area sensor, display, and circuit applications is the fundamental compromise between manufacturing efficiency, transistor performance, and power consumption. In the past, improving the manufacturing efficiency through the use of printing techniques has inevitably resulted in significantly lower performance and increased power consumption, while attempts to improve performance or reduce power have led to higher process temperatures and increased manufacturing cost. Here, we lift this fundamental limitation by demonstrating subfemtoliter inkjet printing to define metal contacts with single-micrometer resolution on the surface of high-mobility organic semiconductors to create high-performance p-channel and n-channel transistors and low-power complementary circuits. The transistors employ an ultrathin low-temperature gate dielectric based on a self-assembled monolayer that allows transistors and circuits on rigid and flexible substrates to operate with very low voltages. PMID:18362348

Estimated performance and future potential of solar dynamic and photovoltaic power systems for selected LEO and HEO missions

NASA Technical Reports Server (NTRS)

Bents, David J.; Lu, Cheng Y.

1989-01-01

Solar photovoltaic and thermal dynamic power systems for application to selected low-earth-orbit (LEO) and high-earth-orbit (HEO) missions are characterized in the regime 7 to 35 kWe. Input parameters to the characterization are varied to correspond to anticipated introduction of improved or new technologies. A comparative assessment is made of the two power system types for emerging technologies in cells and arrays, energy storage, optical surfaces, heat engines, thermal energy storage and thermal management. The assessment is made to common ground rules and assumptions. The four missions (Space Station, sun-synchronous, Van Allen belt, and GEO) are representative of the anticipated range of multikilowatt earth-orbit missions. The results give the expected performance, mass and drag of multikilowatt earth-orbiting solar power systems and show how the overall system figure of merit will improve as new component technologies are incorporated.

A high-power ultrasonic microreactor and its application in gas-liquid mass transfer intensification.

PubMed

Dong, Zhengya; Yao, Chaoqun; Zhang, Xiaoli; Xu, Jie; Chen, Guangwen; Zhao, Yuchao; Yuan, Quan

2015-02-21

The combination of ultrasound and microreactor is an emerging and promising area, but the report of designing high-power ultrasonic microreactor (USMR) is still limited. This work presents a robust, high-power and highly efficient USMR by directly coupling a microreactor plate with a Langevin-type transducer. The USMR is designed as a longitudinal half wavelength resonator, for which the antinode plane of the highest sound intensity is located at the microreactor. According to one dimension design theory, numerical simulation and impedance analysis, a USMR with a maximum power of 100 W and a resonance frequency of 20 kHz was built. The strong and uniform sound field in the USMR was then applied to intensify gas-liquid mass transfer of slug flow in a microfluidic channel. Non-inertial cavitation with multiple surface wave oscillation was excited on the slug bubbles, enhancing the overall mass transfer coefficient by 3.3-5.7 times.

Optimization of power and energy densities in supercapacitors

NASA Astrophysics Data System (ADS)

Robinson, David B.

Supercapacitors use nanoporous electrodes to store large amounts of charge on their high surface areas, and use the ions in electrolytes to carry charge into the pores. Their high power density makes them a potentially useful complement to batteries. However, ion transport through long, narrow channels still limits power and efficiency in these devices. Proper design can mitigate this. Current collector geometry must also be considered once this is done. Here, De Levie's model for porous electrodes is applied to quantitatively predict device performance and to propose optimal device designs for given specifications. Effects unique to nanoscale pores are considered, including that pores may not have enough salt to fully charge. Supercapacitors are of value for electric vehicles, portable electronics, and power conditioning in electrical grids with distributed renewable sources, and that value will increase as new device fabrication methods are developed and proper design accommodates those improvements. Example design outlines for vehicle applications are proposed and compared.

High-power VCSELs for smart munitions

NASA Astrophysics Data System (ADS)

Geske, Jon; MacDougal, Michael; Cole, Garrett; Snyder, Donald

2006-08-01

The next generation of low-cost smart munitions will be capable of autonomously detecting and identifying targets aided partly by the ability to image targets with compact and robust scanning rangefinder and LADAR capabilities. These imaging systems will utilize arrays of high performance, low-cost semiconductor diode lasers capable of achieving high peak powers in pulses ranging from 5 to 25 nanoseconds in duration. Aerius Photonics is developing high-power Vertical-Cavity Surface-Emitting Lasers (VCSELs) to meet the needs of these smart munitions applications. The authors will report the results of Aerius' development program in which peak pulsed powers exceeding 60 Watts were demonstrated from single VCSEL emitters. These compact packaged emitters achieved pulse energies in excess of 1.5 micro-joules with multi kilo-hertz pulse repetition frequencies. The progress of the ongoing effort toward extending this performance to arrays of VCSEL emitters and toward further improving laser slope efficiency will be reported.

Design of experiments with four-factors for a PEM fuel cell optimization

NASA Astrophysics Data System (ADS)

Olteanu, V.; Pǎtularu, L.; Popescu, C. L.; Popescu, M. O.; Crǎciunescu, A.

2017-07-01

Nowadays, many research efforts are allocated for the development of fuel cells, since they constitute a carbon-free electrical energy generator which can be used for stationary, mobile and portable applications. The maximum value of the delivered power of a fuel cell depends on many factors as: the height of plates' channels, the stoichiometry level of the air flow, the air pressure for the cathode, and of the actual operating electric current density. In this paper, two levels, full four-factors factorial experiment has been designed in order to obtain the appropriate response surface which approximates the maximum delivered power dependence of the above-mentioned factors. The optimum set of the fuel-cell factors which determine the maximum value of the delivered power was determined and a comparison between simulated and measured optimal Power versus Current Density characteristics is given.

Robust Features Of Surface Electromyography Signal

NASA Astrophysics Data System (ADS)

Sabri, M. I.; Miskon, M. F.; Yaacob, M. R.

2013-12-01

Nowadays, application of robotics in human life has been explored widely. Robotics exoskeleton system are one of drastically areas in recent robotic research that shows mimic impact in human life. These system have been developed significantly to be used for human power augmentation, robotics rehabilitation, human power assist, and haptic interaction in virtual reality. This paper focus on solving challenges in problem using neural signals and extracting human intent. Commonly, surface electromyography signal (sEMG) are used in order to control human intent for application exoskeleton robot. But the problem lies on difficulty of pattern recognition of the sEMG features due to high noises which are electrode and cable motion artifact, electrode noise, dermic noise, alternating current power line interface, and other noise came from electronic instrument. The main objective in this paper is to study the best features of electromyography in term of time domain (statistical analysis) and frequency domain (Fast Fourier Transform).The secondary objectives is to map the relationship between torque and best features of muscle unit activation potential (MaxPS and RMS) of biceps brachii. This project scope use primary data of 2 male sample subject which using same dominant hand (right handed), age between 20-27 years old, muscle diameter 32cm to 35cm and using single channel muscle (biceps brachii muscle). The experiment conduct 2 times repeated task of contraction and relaxation of biceps brachii when lifting different load from no load to 3kg with ascending 1kg The result shows that Fast Fourier Transform maximum power spectrum (MaxPS) has less error than mean value of reading compare to root mean square (RMS) value. Thus, Fast Fourier Transform maximum power spectrum (MaxPS) show the linear relationship against torque experience by elbow joint to lift different load. As the conclusion, the best features is MaxPS because it has the lowest error than other features and show the linear relationship with torque experience by elbow joint to lift different load.

Immersion Condensation on Oil-Infused Heterogeneous Surfaces for Enhanced Heat Transfer

PubMed Central

Xiao, Rong; Miljkovic, Nenad; Enright, Ryan; Wang, Evelyn N.

2013-01-01

Enhancing condensation heat transfer is important for broad applications from power generation to water harvesting systems. Significant efforts have focused on easy removal of the condensate, yet the other desired properties of low contact angles and high nucleation densities for high heat transfer performance have been typically neglected. In this work, we demonstrate immersion condensation on oil-infused micro and nanostructured surfaces with heterogeneous coatings, where water droplets nucleate immersed within the oil. The combination of surface energy heterogeneity, reduced oil-water interfacial energy, and surface structuring enabled drastically increased nucleation densities while maintaining easy condensate removal and low contact angles. Accordingly, on oil-infused heterogeneous nanostructured copper oxide surfaces, we demonstrated approximately 100% increase in heat transfer coefficient compared to state-of-the-art dropwise condensation surfaces in the presence of non-condensable gases. This work offers a distinct approach utilizing surface chemistry and structuring together with liquid-infusion for enhanced condensation heat transfer. PMID:23759735

Laser-Ultrasonic Testing and its Applications to Nuclear Reactor Internals

NASA Astrophysics Data System (ADS)

Ochiai, M.; Miura, T.; Yamamoto, S.

2008-02-01

A new nondestructive testing technique for surface-breaking microcracks in nuclear reactor components based on laser-ultrasonics is developed. Surface acoustic wave generated by Q-switched Nd:YAG laser and detected by frequency-stabilized long pulse laser coupled with confocal Fabry-Perot interferometer is used to detect and size the cracks. A frequency-domain signal processing is developed to realize accurate sizing capability. The laser-ultrasonic testing allows the detection of surface-breaking microcrack having a depth of less than 0.1 mm, and the measurement of their depth with an accuracy of 0.2 mm when the depth exceeds 0.5 mm including stress corrosion cracking. The laser-ultrasonic testing system combined with laser peening system, which is another laser-based maintenance technology to improve surface stress, for inner surface of small diameter tube is developed. The generation laser in the laser-ultrasonic testing system can be identical to the laser source of the laser peening. As an example operation of the system, the system firstly works as the laser-ultrasonic testing mode and tests the inner surface of the tube. If no cracks are detected, the system then changes its work mode to the laser peening and improves surface stress to prevent crack initiation. The first nuclear industrial application of the laser-ultrasonic testing system combined with the laser peening was completed in Japanese nuclear power plant in December 2004.

30 nm T-gate enhancement-mode InAlN/AlN/GaN HEMT on SiC substrates for future high power RF applications

NASA Astrophysics Data System (ADS)

Murugapandiyan, P.; Ravimaran, S.; William, J.

2017-08-01

The DC and RF performance of 30 nm gate length enhancement mode (E-mode) InAlN/AlN/GaN high electron mobility transistor (HEMT) on SiC substrate with heavily doped source and drain region have been investigated using the Synopsys TCAD tool. The proposed device has the features of a recessed T-gate structure, InGaN back barrier and Al2O3 passivated device surface. The proposed HEMT exhibits a maximum drain current density of 2.1 A/mm, transconductance {g}{{m}} of 1050 mS/mm, current gain cut-off frequency {f}{{t}} of 350 GHz and power gain cut-off frequency {f}\\max of 340 GHz. At room temperature the measured carrier mobility (μ), sheet charge carrier density ({n}{{s}}) and breakdown voltage are 1580 cm2/(V \\cdot s), 1.9× {10}13 {{cm}}-2, and 10.7 V respectively. The superlatives of the proposed HEMTs are bewitching competitor or future sub-millimeter wave high power RF VLSI circuit applications.

Application of Multihop Relay for Performance Enhancement of AeroMACS Networks

NASA Technical Reports Server (NTRS)

Kamali, Behnam; Wilson, Jeffrey D.; Kerczewski, Robert J.

2012-01-01

A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091-5150 MHz has been created by ITU to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.

Application of Multihop Relay for Performance Enhancement of AeroMACS Networks

NASA Technical Reports Server (NTRS)

Kamali, Behnam; Wilson, Jeffrey D.; Kerczewski, Robert J.

2012-01-01

A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091 to 5150 MHz has been created by International Telecommunications Union (ITU) to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.

Introduction to Generalized Functions with Applications in Aerodynamics and Aeroacoustics

NASA Technical Reports Server (NTRS)

Farassat, F.

1994-01-01

Generalized functions have many applications in science and engineering. One useful aspect is that discontinuous functions can be handled as easily as continuous or differentiable functions and provide a powerful tool in formulating and solving many problems of aerodynamics and acoustics. Furthermore, generalized function theory elucidates and unifies many ad hoc mathematical approaches used by engineers and scientists. We define generalized functions as continuous linear functionals on the space of infinitely differentiable functions with compact support, then introduce the concept of generalized differentiation. Generalized differentiation is the most important concept in generalized function theory and the applications we present utilize mainly this concept. First, some results of classical analysis, are derived with the generalized function theory. Other applications of the generalized function theory in aerodynamics discussed here are the derivations of general transport theorems for deriving governing equations of fluid mechanics, the interpretation of the finite part of divergent integrals, the derivation of the Oswatitsch integral equation of transonic flow, and the analysis of velocity field discontinuities as sources of vorticity. Applications in aeroacoustics include the derivation of the Kirchhoff formula for moving surfaces, the noise from moving surfaces, and shock noise source strength based on the Ffowcs Williams-Hawkings equation.