422 research outputs found
Plasma Nanoscience: from Nano-Solids in Plasmas to Nano-Plasmas in Solids
The unique plasma-specific features and physical phenomena in the
organization of nanoscale solid-state systems in a broad range of elemental
composition, structure, and dimensionality are critically reviewed. These
effects lead to the possibility to localize and control energy and matter at
nanoscales and to produce self-organized nano-solids with highly unusual and
superior properties. A unifying conceptual framework based on the control of
production, transport, and self-organization of precursor species is introduced
and a variety of plasma-specific non-equilibrium and kinetics-driven phenomena
across the many temporal and spatial scales is explained. When the plasma is
localized to micrometer and nanometer dimensions, new emergent phenomena arise.
The examples range from semiconducting quantum dots and nanowires, chirality
control of single-walled carbon nanotubes, ultra-fine manipulation of
graphenes, nano-diamond, and organic matter, to nano-plasma effects and
nano-plasmas of different states of matter.Comment: This is an essential interdisciplinary reference which can be used by
both advanced and early career researchers as well as in undergraduate
teaching and postgraduate research trainin
Interaction effects in thermocapillary bubble migration
Two bubbles migrating along their line of centers under the influence of an imposed thermal gradient are considered in the quasi-static limit. Results are reported for representative values of the governing parameters
Carbon Nanotube Based Nanotechnology for NASA Mission Needs and Societal Applications
Carbon nanotubes (CNT) exhibit extraordinary mechanical properties and unique electronic properties and therefore, have received much attention for more than a decade now for a variety of applications ranging from nanoelectronics, composites to meeting needs in energy, environmental and other sectors. In this talk, we focus on some near term potential of CNT applications for both NASA and other Agency/societal needs. The most promising and successful application to date is a nano chem sensor at TRL 6 that uses a 16-256 sensor array in the construction of an electronic nose. Pristine, doped, functionalized and metal-loaded SWCNTs are used as conducting materials to provide chemical variation across the individual elements of the sensor array. This miniaturized sensor has been incorporated in an iPhone for homeland security applications. Gases and vapors relevant to leak detection in crew vehicles, biomedical, mining, chemical threats, industrial spills and others have been demonstrated. SWCNTs also respond to radiation exposure via a change in conductivity and therefore, a similar strategy is being pursued to construct a radiation nose to identify radiation sources (gamma, protons, neutrons, X-ray, etc.) with their energy levels. Carbon nanofibers (CNFs) grown using plasma enhanced CVD typically are vertical, individual, freestanding structures and therefore, are ideal for construction of nanoelectrodes. A nanoelectrode array (NEA) can be the basis for an affinity-based biosensor to meet the needs in applications such as lab-on-a-chip, environmental monitoring, cancer diagnostics, biothreat monitoring, water and food safety and others. A couple of demonstrations including detection of e-coli and ricin will be discussed. The NEA is also useful for implantation in the brain for deep brain stimulation and neuroengineering applications. Miniaturization of payload such as science instrumentation and power sources is critical to reduce launch costs. High current density (greater than 100 mA/per square centimeters) field emission capabilities of CNTs can be exploited for construction of electron gun for electron microscopy and X-ray tubes for spectrometers and baggage screening. A CNT pillar array configuration has been demonstrated, not only meeting the high current density needs but more importantly providing long term emitter stability. Finally, supercapacitors hold the promise to combine the high energy density of a battery with the high power density of capacitors. Traditional graphite electrodes have not delivered this promise yet. A novel design and processing approach using MWCNTs has shown a record 550 F/g capacitance along with significant device endurance. This supercapacitor is suitable for railgun launch application for NASA, powering rovers and robots, consumer electronics and future hybrid vehicles
Carbon-Nanotube-Based Electrodes for Biomedical Applications
A nanotube array based on vertically aligned nanotubes or carbon nanofibers has been invented for use in localized electrical stimulation and recording of electrical responses in selected regions of an animal body, especially including the brain. There are numerous established, emerging, and potential applications for localized electrical stimulation and/or recording, including treatment of Parkinson s disease, Tourette s syndrome, and chronic pain, and research on electrochemical effects involved in neurotransmission. Carbon-nanotube-based electrodes offer potential advantages over metal macroelectrodes (having diameters of the order of a millimeter) and microelectrodes (having various diameters ranging down to tens of microns) heretofore used in such applications. These advantages include the following: a) Stimuli and responses could be localized at finer scales of spatial and temporal resolution, which is at subcellular level, with fewer disturbances to, and less interference from, adjacent regions. b) There would be less risk of hemorrhage on implantation because nano-electrode-based probe tips could be configured to be less traumatic. c) Being more biocompatible than are metal electrodes, carbon-nanotube-based electrodes and arrays would be more suitable for long-term or permanent implantation. d) Unlike macro- and microelectrodes, a nano-electrode could penetrate a cell membrane with minimal disruption. Thus, for example, a nanoelectrode could be used to generate an action potential inside a neuron or in proximity of an active neuron zone. Such stimulation may be much more effective than is extra- or intracellular stimulation via a macro- or microelectrode. e) The large surface area of an array at a micron-scale footprint of non-insulated nanoelectrodes coated with a suitable electrochemically active material containing redox ingredients would make it possible to obtain a pseudocapacitance large enough to dissipate a relatively large amount of electric charge, so that a large stimulation current could be applied at a micron-scale region without exhausting the redox ingredients. f) Carbon nanotube array is more compatible with the three-dimensional network of tissues. Particularly, a better electrical-neural interface can be formed. g) A carbon nanotube array inlaid in insulating materials with only the ends exposed is an extremely sensitive electro-analysis tool that can measure the local neurotransmitter signal at extremely high sensitivity and temporal resolution
Low-Temperature Plasma Functionalization of Carbon Nanotubes
A low-temperature plasma process has been devised for attaching specified molecular groups to carbon nanotubes in order to impart desired chemical and/or physical properties to the nanotubes for specific applications. Unlike carbon-nanotube- functionalization processes reported heretofore, this process does not involve the use of wet chemicals, does not involve exposure of the nanotubes to high temperatures, and generates very little chemical residue. In addition, this process can be carried out in a relatively simple apparatus and can readily be scaled up to mass production
A Survey of the Rapidly Emerging Field of Nanotechnology: Potential Applications for Scientific Instruments and Technologies for Atmospheric Entry Probes
The field of Nanotechnology is well funded worldwide and innovations applicable to Solar System Exploration are emerging much more rapidly than thought possible just a few years ago. This presentation will survey recent innovations from nanotechnololgy with a focus on novel applications to atmospheric entry science and probe technology, in a fashion similar to that presented by Arnold and Venkatapathy at the previous workshop forum at Lisbon Portugal, October 6-9, 2003. Nanotechnology is a rapidly emerging field that builds systems, devices and materials from the bottom up, atom by atom, and in so doing provides them with novel and remarkable macro-scale performance. This technology has the potential to revolutionize space exploration by reducing mass and simultaneously increasing capability. Thermal, Radiation, Impact Protective Shields: Atmospheric probes and humans on long duration deep space missions involved in Solar System Exploration must safely endure 3 significant hazards: (i) atmospheric entry; (ii) radiation; and (iii) micrometeorite or debris impact. Nanostructured materials could be developed to address all three hazards with a single protective shield, which would involve much less mass than a traditional approach. The concept can be ready in time for incorporation into NASA s Crew Exploration Vehicle, and possible entry probes to fly on the Jupiter Icy Moon
Biochemical Sensors Using Carbon Nanotube Arrays
Method and system for detecting presence of biomolecules in a selected subset, or in each of several selected subsets, in a fluid. Each of an array of two or more carbon nanotubes ("CNTs") is connected at a first CNT end to one or more electronics devices, each of which senses a selected electrochemical signal that is generated when a target biomolecule in the selected subset becomes attached to a functionalized second end of the CNT, which is covalently bonded with a probe molecule. This approach indicates when target biomolecules in the selected subset are present and indicates presence or absence of target biomolecules in two or more selected subsets. Alternatively, presence of absence of an analyte can be detected
MAPPING OF SITTAMPUNDI ANORTHOSITE COMPLEX (SAC) IN SOUTHERN GRANULITE TERRAIN (SGT), INDIA WITH ASTER AND SENTINEL-2A DATA
The Sittampundi Anorthosite Complex (SAC) is a well-exposed Archean layered anorthosite-gabbro- ultramafic rock complex in southern India. SAC well preserved white- and dark-anorthosite,gabbros, and ultramafic rocks. This study aims to discriminate, characterize, and separate from adjacent and surrounding rocks the anorthosite complex in sitampundi using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Sentinel-2A data. Methods such as band color composites (True color composite, False color composite and Pseudo color composite), Principal Component Analysis (PCA), Minimum Noise Fraction (MNF) and Spectral Angle Mapper (SAM), are applied to discriminate the anorthosite complex in SGT (Southern Granulite Terrain). Band composites enhance the litho units using visible and shortwave infrared bands and thus, assisted in mapping for the anorthosite complex. PCA and MNF have been applied to the ASTER and Sentinel- 2A bands in order to decrease the redundant information in highly correlated bands. PCA and MNF driven band combinations facilitate the validation and help in discriminating the various lithological units exposed in the study area. SAM classifier classification technique was utilized to characterize the selected surface mineral assemblages from Sitampundi Anorthosite Complex using spectral signatures. The above- mentioned digital image processing techniques have been proven resourceful in discrimination of anorthosite complex and associated rocks. The results obtained from ASTER and Sentinel-2A data processing were validated in field, followed by accuracy assessment
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