Shebanova, A S; Bogdanov, A G; Ismagulova, T T; Feofanov, A V; Semenyuk, P I; Muronets, V I; Erokhina, M V; Onishchenko, G E; Kirpichnikov, M P; Shaitan, K V
2014-01-01
This work represents the results of the study on applicability of the modern methods of analytical transmission electron microscopy for detection, identification and visualization of localization of nanoparticles of titanium and cerium oxides in A549 cell, human lung adenocarcinoma cell line. A comparative analysis of images of the nanoparticles in the cells obtained in the bright field mode of transmission electron microscopy, under dark-field scanning transmission electron microscopy and high-angle annular dark field scanning transmission electron was performed. For identification of nanoparticles in the cells the analytical techniques, energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy, were compared when used in the mode of obtaining energy spectrum from different particles and element mapping. It was shown that the method for electron tomography is applicable to confirm that nanoparticles are localized in the sample but not coated by contamination. The possibilities and fields of utilizing different techniques for analytical transmission electron microscopy for detection, visualization and identification of nanoparticles in the biological samples are discussed.
Phase-space dynamics of runaway electrons in magnetic fields
Guo, Zehua; McDevitt, Christopher Joseph; Tang, Xian-Zhu
2017-02-16
Dynamics of runaway electrons in magnetic fields are governed by the competition of three dominant physics: parallel electric field acceleration, Coulomb collision, and synchrotron radiation. Examination of the energy and pitch-angle flows reveals that the presence of local vortex structure and global circulation is crucial to the saturation of primary runaway electrons. Models for the vortex structure, which has an O-point to X-point connection, and the bump of runaway electron distribution in energy space have been developed and compared against the simulation data. Lastly, identification of these velocity-space structures opens a new venue to re-examine the conventional understanding of runawaymore » electron dynamics in magnetic fields.« less
Energetic electron anisotropies in the magnetotail - Identification of open and closed field lines
NASA Technical Reports Server (NTRS)
Baker, D. N.; Stone, E. C.
1976-01-01
Unidirectional anisotropies in the energetic electron fluxes (E greater than or equal to about 200 keV) have been observed in the earth's magnetotail with the Caltech Electron/Isotope Spectrometer on IMP-8. The anisotropies occur during periods of enhanced fluxes and provide essential information on the topology (open or closed) of the magnetotail field lines which are associated with recently identified acceleration regions.
Electron spin resonance identification of irradiated fruits
NASA Astrophysics Data System (ADS)
Raffi, Jacques J.; Agnel, Jean-Pierre L.
The electron spin resonance spectrum of achenes, pips, stalks and stones from irradiated fruits (strawberry, raspberry, red currant, bilberry, apple, pear, fig, french prune, kiwi, water-melon and cherry) always displays, just after γ-treatment, a weak triplet ( aH≈30 G) due to a cellulose radical; its left line (lower field) can be used as an identification test of irradiation, at least for strawberries, rapsberries, red currants or bilberries irradiated in order to improve their storage time.
Field theory of pattern identification
NASA Astrophysics Data System (ADS)
Agu, Masahiro
1988-06-01
Based on the psychological experimental fact that images in mental space are transformed into other images for pattern identification, a field theory of pattern identification of geometrical patterns is developed with the use of gauge field theory in Euclidean space. Here, the ``image'' or state function ψ[χ] of the brain reacting to a geometrical pattern χ is made to correspond to the electron's wave function in Minkowski space. The pattern identification of the pattern χ with the modified pattern χ+Δχ is assumed to be such that their images ψ[χ] and ψ[χ+Δχ] in the brain are transformable with each other through suitable transformation groups such as parallel transformation, dilatation, or rotation. The transformation group is called the ``image potential'' which corresponds to the vector potential of the gauge field. An ``image field'' derived from the image potential is found to be induced in the brain when the two images ψ[χ] and ψ[χ+Δχ] are not transformable through suitable transformation groups or gauge transformations. It is also shown that, when the image field exists, the final state of the image ψ[χ] is expected to be different, depending on the paths of modifications of the pattern χ leading to a final pattern. The above fact is interpreted as a version of the Aharonov and Bohm effect of the electron's wave function [A. Aharonov and D. Bohm, Phys. Rev. 115, 485 (1959)]. An excitation equation of the image field is also derived by postulating that patterns are identified maximally for the purpose of minimizing the number of memorized standard patterns.
Electronic labelling in recycling of manufactured articles.
Olejnik, Lech; Krammer, Alfred
2002-12-01
The concept of a recycling system aiming at the recovery of resources from manufactured articles is proposed. The system integrates electronic labels for product identification and internet for global data exchange. A prototype for the recycling of electric motors has been developed, which implements a condition-based recycling decision system to automatically select the environmentally and economically appropriate recycling strategy, thereby opening a potential market for second-hand motors and creating a profitable recycling process itself. The project has been designed to evaluate the feasibility of electronic identification applied on a large number of motors and to validate the system in real field conditions.
The Diogene 4 pi detector at Saturne
NASA Technical Reports Server (NTRS)
Alard, J. P.; Arnold, J.; Augerat, J.; Babinet, R.; Bastid, N.; Brochard, F.; Costilhes, J. P.; Crouau, M.; De Marco, N.; Drouet, M.;
1987-01-01
Diogene, an electronic 4 pi detector, has been built and installed at the Saturne synchrotron in Saclay. The forward angular range (0 degree-6 degrees) is covered by 48 time-of-flight scintillator telescopes that provide charge identification. The trajectories of fragments emitted at larger angles are recorded in a cylindrical 0.4-m3 Pictorial Drift Chamber (PDC) surrounding the target. The PDC is inside a 1-T magnetic field; the axis of the PDC cylinder and the magnetic field are parallel to the beam. Good identification has been obtained for both positive and negative pi mesons and for hydrogen and helium isotopes. Multiplicities in relativistic nucleus-nucleus reactions up to 40 have been detected, limited mainly by the present electronics.
Complementarity of Laboratory and Space Experiments on Reconnexion
NASA Astrophysics Data System (ADS)
Moore, T. E.; Chen, L. J.
2017-12-01
Reconnection research has for some time been focused upon understanding the electron scale physics in the electron diffusion region (EDR), both in space and in the laboratory. Ren et al. [2008 PRL] reported identification and resolution of the EDR in the MRX laboratory experiment. More recently, Burch et al. [2016] reported identification of the EDR in reconnection at the magnetopause. Space observations from MMS have also provided the first capability to resolve and measure the full electron VDF within and around the EDR, making it possible to observe electron acceleration by the reconnection electric field and revealing new features of the EDR. Laboratory and space explorations of EDR physics may complement and inspire each other in other ways to be discussed by the panel.
Electron Energization and Structure of the Diffusion Region During Asymmetric Reconnection
NASA Technical Reports Server (NTRS)
Chen, Li-Jen; Hesse, Michael; Wang, Shan; Bessho, Naoki; Daughton, William
2016-01-01
Results from particle-in-cell simulations of reconnection with asymmetric upstream conditions are reported to elucidate electron energization and structure of the electron diffusion region (EDR). Acceleration of unmagnetized electrons results in discrete structures in the distribution functions and supports the intense current and perpendicular heating in the EDR. The accelerated electrons are cyclotron turned by the reconnected magnetic field to produce the outflow jets, and as such, the acceleration by the reconnection electric field is limited, leading to resistivity without particle-particle or particle-wave collisions. A map of electron distributions is constructed, and its spatial evolution is compared with quantities previously proposed to be EDR identifiers to enable effective identifications of the EDR in terrestrial magnetopause reconnection.
Yuan, Shi-Jie; He, Hui; Sheng, Guo-Ping; Chen, Jie-Jie; Tong, Zhong-Hua; Cheng, Yuan-Yuan; Li, Wen-Wei; Lin, Zhi-Qi; Zhang, Feng; Yu, Han-Qing
2013-01-01
Electrochemically active bacteria (EAB) are ubiquitous in environment and have important application in the fields of biogeochemistry, environment, microbiology and bioenergy. However, rapid and sensitive methods for EAB identification and evaluation of their extracellular electron transfer ability are still lacking. Herein we report a novel photometric method for visual detection of EAB by using an electrochromic material, WO(3) nanoclusters, as the probe. This method allowed a rapid identification of EAB within 5 min and a quantitative evaluation of their extracellular electron transfer abilities. In addition, it was also successfully applied for isolation of EAB from environmental samples. Attributed to its rapidness, high reliability, easy operation and low cost, this method has high potential for practical implementation of EAB detection and investigations.
Development of the ZEUS central tracking detector
NASA Astrophysics Data System (ADS)
Brooks, C. B.; Bullock, F. W.; Cashmore, R. J.; Devenish, R. C.; Foster, B.; Fraser, T. J.; Gibson, M. D.; Gilmore, R. S.; Gingrich, D.; Harnew, N.; Hart, J. C.; Heath, G. P.; Hiddleston, J.; Holmes, A. R.; Jamdagni, A. K.; Jones, T. W.; Llewellyn, T. J.; Long, K. R.; Lush, G. J.; Malos, J.; Martin, N. C.; McArthur, I.; McCubbin, N. A.; McQuillan, D.; Miller, D. B.; Mobayyen, M. M.; Morgado, C.; Nash, J.; Nixon, G.; Parham, A. G.; Payne, B. T.; Roberts, J. H. C.; Salmon, G.; Saxon, D. H.; Sephton, A. J.; Shaw, D.; Shaw, T. B.; Shield, P. D.; Shulman, J.; Silvester, I.; Smith, S.; Strachan, D. E.; Tapper, R. J.; Tkaczyk, S. M.; Toudup, L. W.; Wallis, E. W.; Wastie, R.; Wells, J.; White, D. J.; Wilson, F. F.; Yeo, K. L.; ZEUS-UK Collaboration
1989-11-01
The design concept and development of the ZEUS central tracking detector is described. This is a cylindrical drift chamber designed for track reconstruction, electron identification and event triggering in a high-crossing-rate, high-magnetic-field environment.
Maven Observations of Electron-Induced Whistler Mode Waves in the Martian Magnetosphere
NASA Technical Reports Server (NTRS)
Harada, Y.; Andersson, L.; Fowler, C. M.; Mitchell, D. L.; Halekas, J. S.; Mazelle, C.; Espley, J.; DiBraccio, G. A.; McFadden, J. P.; Brian, D. A.;
2016-01-01
We report on narrowband electromagnetic waves at frequencies between the local electron cyclotron and lower hybrid frequencies observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft in the Martian induced magnetosphere. The peaked electric field wave spectra below the electron cyclotron frequency were first observed by Phobos-2 in the Martian magnetosphere, but the lack of magnetic field wave data prevented definitive identification of the wave mode and their generation mechanisms remain unclear. Analysis of electric and magnetic field wave spectra obtained by MAVEN demonstrates that the observed narrowband waves have properties consistent with the whistler mode. Linear growth rates computed from the measured electron velocity distributions suggest that these whistler mode waves can be generated by cyclotron resonance with anisotropic electrons. Large electron anisotropy in the Martian magnetosphere is caused by absorption of parallel electrons by the collisional atmosphere. The narrowband whistler mode waves and anisotropic electrons are observed on both open and closed field lines and have similar spatial distributions in MSO and planetary coordinates. Some of the waves on closed field lines exhibit complex frequency-time structures such as discrete elements of rising tones and two bands above and below half the electron cyclotron frequency. These MAVEN observations indicate that whistler mode waves driven by anisotropic electrons, which are commonly observed in intrinsic magnetospheres and at unmagnetized airless bodies, are also present at Mars. The wave-induced electron precipitation into the Martian atmosphere should be evaluated in future studies.
VLF emissions in the Venus foreshock - Comparison with terrestrial observations
NASA Technical Reports Server (NTRS)
Crawford, G. K.; Strangeway, R. J.; Russell, C. T.
1993-01-01
An examination is conducted of ELF/VLF emissions observed in the solar wind upstream of the Venus shock, for the 100 Hz-30 kHz range, using data from the Pioneer Venus Orbiter's electric field detector and magnetometer instruments. Detailed comparisons are made with terrestrial measurements for both the electron and ion foreshocks. The results obtained support the Crawford et al. (1990) identification of the Venus electron foreshock emissions as electron plasma oscillations, whose waves are generated in situ and act to isotropize the electron distributions.
NASA Astrophysics Data System (ADS)
Dombeck, J. P.; Cattell, C. A.; Prasad, N.; Sakher, A.; Hanson, E.; McFadden, J. P.; Strangeway, R. J.
2016-12-01
Field-aligned currents (FACs) provide a fundamental driver and means of Magnetosphere-Ionosphere (M-I) coupling. These currents need to be supported by local physics along the entire field line generally with quasi-static potential structures, but also supporting the time-evolution of the structures and currents, producing Alfvén waves and Alfvénic electron acceleration. In regions of upward current, precipitating auroral electrons are accelerated earthward. These processes can result in ion outflow, changes in ionospheric conductivity, and affect the particle distributions on the field line, affecting the M-I coupling processes supporting the individual FACs and potentially the entire FAC system. The FAST mission was well suited to study both the FACs and the electron auroral acceleration processes. We present the results of the comparisons between meso- and small-scale FACs determined from FAST using the method of Peria, et al., 2000, and our FAST auroral acceleration mechanism study when such identification is possible for the entire ˜13 year FAST mission. We also present the latest results of the electron energy (and number) flux ionospheric input based on acceleration mechanism (and FAC characteristics) from our FAST auroral acceleration mechanism study.
Big Data Quality Case Study Preliminary Findings, U.S. Army MEDCOM MODS
2013-09-01
captured in electronic form is relatively small, on the order of hundreds of thousands of health profiles at say around 500K per profile, or in the...in electronic form, then different language identification, handwriting recognition, and Natural Language Processing (NLP) techniques could be used...and patterns” [15]. Volume - The free text fields vary in length from say ten characters to several hundred characters. Other materials can be much
Porto Ferreira, Cassio; Oliveira de Almeida, Ana Cristina; Corte-Real, Suzana
2015-01-01
Transmission electron microscopy can yield useful information in a range of scientific fields; it is capable of imaging at a significantly higher resolution than light microscopes and has been a very useful tool in the identification of morphological changes of the dermis as well as assessment of changes in the extracellular matrix. Our aim is to characterize by electron microscopy the cellular profile of lesions caused by Sporothrix schenckii from the sporotrichosis epidemic in its zoonotic form that occurs in Rio de Janeiro, Brazil. PMID:25653392
2011-04-25
contract to assist the Afghan government in collecting and managing the biometric data for all of the ANSF. 5. The Electronic Payroll System (EPS...Identification cards numbers will be utilized as the common data fields for the various payroll , biometric , and personnel databases and systems. In addition to...data in MoI’s payroll , personnel, identification card/registration, and biometric databases and systems. 3. Take the following steps as part of all
NASA Astrophysics Data System (ADS)
Facsko, Gabor; Sibeck, David; Balogh, Tamas; Kis, Arpad; Wesztergom, Viktor
2017-04-01
The bow shock and the outer rim of the outer radiation belt are detected automatically by our algorithm developed as a part of the Boundary Layer Identification Code Cluster Active Archive project. The radiation belt positions are determined from energized electron measurements working properly onboard all Cluster spacecraft. For bow shock identification we use magnetometer data and, when available, ion plasma instrument data. In addition, electrostatic wave instrument electron density, spacecraft potential measurements and wake indicator auxiliary data are also used so the events can be identified by all Cluster probes in highly redundant way, as the magnetometer and these instruments are still operational in all spacecraft. The capability and performance of the bow shock identification algorithm were tested using known bow shock crossing determined manually from January 29, 2002 to February 3,. The verification enabled 70% of the bow shock crossings to be identified automatically. The method shows high flexibility and it can be applied to observations from various spacecraft. Now these tools have been applied to Time History of Events and Macroscale Interactions during Substorms (THEMIS)/Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) magnetic field, plasma and spacecraft potential observations to identify bow shock crossings; and to Van Allen Probes supra-thermal electron observations to identify the edges of the radiation belt. The outcomes of the algorithms are checked manually and the parameters used to search for bow shock identification are refined.
Measurements by the plasma diagnostics package on STS-3
NASA Technical Reports Server (NTRS)
Shawhan, S. D.; Murphy, G. B.
1982-01-01
A comprehensive set of measurements about the orbiter environment are provided by the plasma diagnostics package (PDP). Ion and electron particle densities, energies, and spatial distribution functions; ion mass for identification of particular molecular ion species; and magnetic fields, electric fields and electromagnetic waves over a broad frequency range are studied. Shuttle environmental measurements will be made both on the pallet and, by use of the remote manipulator system (RMS), the PDP will be maneuvered in and external to the bay area to continue environmental measurements and to carry on a joint plasma experiment with the Utah State University fast-pulsed electron generator. Results of orbiter environment EMI measurements and S-band field strengths as well as preliminary results from wake search operations indicating wake boundary identifiers are reported.
Ferreira, Cassio Porto; Oliveira de Almeida, Ana Cristina; Corte-Real, Suzana
2015-02-01
Transmission electron microscopy can yield useful information in a range of scientific fields; it is capable of imaging at a significantly higher resolution than light microscopes and has been a very useful tool in the identification of morphological changes of the dermis as well as assessment of changes in the extracellular matrix. Our aim is to characterize by electron microscopy the cellular profile of lesions caused by Sporothrix schenckii from the sporotrichosis epidemic in its zoonotic form that occurs in Rio de Janeiro, Brazil. © The American Society of Tropical Medicine and Hygiene.
Atomic-scale identification of novel planar defect phases in heteroepitaxial YBa2Cu3O7-δ thin films
NASA Astrophysics Data System (ADS)
Gauquelin, Nicolas; Zhang, Hao; Zhu, Guozhen; Wei, John Y. T.; Botton, Gianluigi A.
2018-05-01
We have discovered two novel types of planar defects that appear in heteroepitaxial YBa2Cu3O7-δ (YBCO123) thin films, grown by pulsed-laser deposition (PLD) either with or without a La2/3Ca1/3MnO3 (LCMO) overlayer, using the combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging and electron energy loss spectroscopy (EELS) mapping for unambiguous identification. These planar lattice defects are based on the intergrowth of either a BaO plane between two CuO chains or multiple Y-O layers between two CuO2 planes, resulting in non-stoichiometric layer sequences that could directly impact the high-Tc superconductivity.
Selected Issues in DoD’s Radio Frequency Identification (RFID) Implementation
2006-04-01
Evaluation of human exposure to electromagnetic fields from devices operating in the frequency range 0 Hz to 10 GHz, used in Electronic...standard for human exposure to RF Signal, 3 kHz-300 GHz BS EN 50364 Limitation of human exposure to electromagnetic fields from devices operating in the...Management and DoD Explosives Safety Board, and DoDD 6055.9-STD, DoD Ammunition and Explosives Safety Standards. Exposure of people to electromagnetic
NASA Astrophysics Data System (ADS)
Lynam, Jeff R.
2001-09-01
A more highly integrated, electro-optical sensor suite using Laser Illuminated Viewing and Ranging (LIVAR) techniques is being developed under the Army Advanced Concept Technology- II (ACT-II) program for enhanced manportable target surveillance and identification. The ManPortable LIVAR system currently in development employs a wide-array of sensor technologies that provides the foot-bound soldier and UGV significant advantages and capabilities in lightweight, fieldable, target location, ranging and imaging systems. The unit incorporates a wide field-of-view, 5DEG x 3DEG, uncooled LWIR passive sensor for primary target location. Laser range finding and active illumination is done with a triggered, flash-lamp pumped, eyesafe micro-laser operating in the 1.5 micron region, and is used in conjunction with a range-gated, electron-bombarded CCD digital camera to then image the target objective in a more- narrow, 0.3$DEG, field-of-view. Target range determination is acquired using the integrated LRF and a target position is calculated using data from other onboard devices providing GPS coordinates, tilt, bank and corrected magnetic azimuth. Range gate timing and coordinated receiver optics focus control allow for target imaging operations to be optimized. The onboard control electronics provide power efficient, system operations for extended field use periods from the internal, rechargeable battery packs. Image data storage, transmission, and processing performance capabilities are also being incorporated to provide the best all-around support, for the electronic battlefield, in this type of system. The paper will describe flash laser illumination technology, EBCCD camera technology with flash laser detection system, and image resolution improvement through frame averaging.
Phosphorus detection in vitrified bacteria by cryo-STEM annular dark-field analysis.
Wolf, Sharon Grayer; Rez, Peter; Elbaum, Michael
2015-11-01
Bacterial cells often contain dense granules. Among these, polyphosphate bodies (PPBs) store inorganic phosphate for a variety of essential functions. Identification of PPBs has until now been accomplished by analytical methods that required drying or chemically fixing the cells. These methods entail large electron doses that are incompatible with low-dose imaging of cryogenic specimens. We show here that Scanning Transmission Electron Microscopy (STEM) of fully hydrated, intact, vitrified bacteria provides a simple means for mapping of phosphorus-containing dense granules based on quantitative sensitivity of the electron scattering to atomic number. A coarse resolution of the scattering angles distinguishes phosphorus from the abundant lighter atoms: carbon, nitrogen and oxygen. The theoretical basis is similar to Z contrast of materials science. EDX provides a positive identification of phosphorus, but importantly, the method need not involve a more severe electron dose than that required for imaging. The approach should prove useful in general for mapping of heavy elements in cryopreserved specimens when the element identity is known from the biological context. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.
Laser-aided material identification for the waste sorting process
NASA Astrophysics Data System (ADS)
Haferkamp, Heinz; Burmester, Ingo; Engel, Kai
1994-03-01
The LZH has carried out investigations in the field of rapid laser-supported material- identification systems for automatic material-sorting systems. The aim of this research is the fast identification of different sorts of plastics coming from recycled rubbish or electronic waste. Within a few milliseconds a spot on the sample which has to be identified is heated with a CO2 laser. The different and specific chemical and physical material properties of the examined sample cause a different temperature distribution on the surface which is measured with an IR thermographic system. This `thermal impulse response' has to be analyzed by means of a computer system. The results of previous investigations have shown that material identification of different sorts of plastics can possibly be done at a frequency of 30 Hz. Due to economic efficiency, a high velocity identification process is necessary to sort huge waste currents.
Kletsov, Aleksey A; Glukhovskoy, Evgeny G; Chumakov, Aleksey S; Ortiz, Joseph V
2016-01-01
The conduction properties of DNA molecule, particularly its transverse conductance (electron transfer through nucleotide bridges), represent a point of interest for DNA chemistry community, especially for DNA sequencing. However, there is no fully developed first-principles theory for molecular conductance and current that allows one to analyze the transverse flow of electrical charge through a nucleotide base. We theoretically investigate the transverse electron transport through all four DNA nucleotide bases by implementing an unbiased ab initio theoretical approach, namely, the electron propagator theory. The electrical conductance and current through DNA nucleobases (guanine [G], cytosine [C], adenine [A] and thymine [T]) inserted into a model 1-nm Ag-Ag nanogap are calculated. The magnitudes of the calculated conductance and current are ordered in the following hierarchies: gA>gG>gC>gT and IG>IA>IT>IC correspondingly. The new distinguishing parameter for the nucleobase identification is proposed, namely, the onset bias magnitude. Nucleobases exhibit the following hierarchy with respect to this parameter: Vonset(A)
Experiments in automatic word class and word sense identification for information retrieval
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gauch, S.; Futrelle, R.P.
Automatic identification of related words and automatic detection of word senses are two long-standing goals of researchers in natural language processing. Word class information and word sense identification may enhance the performance of information retrieval system4ms. Large online corpora and increased computational capabilities make new techniques based on corpus linguisitics feasible. Corpus-based analysis is especially needed for corpora from specialized fields for which no electronic dictionaries or thesauri exist. The methods described here use a combination of mutual information and word context to establish word similarities. Then, unsupervised classification is done using clustering in the word space, identifying word classesmore » without pretagging. We also describe an extension of the method to handle the difficult problems of disambiguation and of determining part-of-speech and semantic information for low-frequency words. The method is powerful enough to produce high-quality results on a small corpus of 200,000 words from abstracts in a field of molecular biology.« less
NASA Technical Reports Server (NTRS)
Nittler, Larry R.
2003-01-01
This grant furnished funds to purchase a state-of-the-art scanning electron microscope (SEM) to support our analytical facilities for extraterrestrial samples. After evaluating several instruments, we purchased a JEOL 6500F thermal field emission SEM with the following analytical accessories: EDAX energy-dispersive x-ray analysis system with fully automated control of instrument and sample stage; EDAX LEXS wavelength-dispersive x-ray spectrometer for high sensitivity light-element analysis; EDAX/TSL electron backscatter diffraction (EBSD) system with software for phase identification and crystal orientation mapping; Robinson backscatter electron detector; and an in situ micro-manipulator (Kleindiek). The total price was $550,000 (with $150,000 of the purchase supported by Carnegie institution matching funds). The microscope was delivered in October 2002, and most of the analytical accessories were installed by January 2003. With the exception of the wavelength spectrometer (which has been undergoing design changes) everything is working well and the SEM is in routine use in our laboratory.
Magnetic forces and localized resonances in electron transfer through quantum rings.
Poniedziałek, M R; Szafran, B
2010-11-24
We study the current flow through semiconductor quantum rings. In high magnetic fields the current is usually injected into the arm of the ring preferred by classical magnetic forces. However, for narrow magnetic field intervals that appear periodically on the magnetic field scale the current is injected into the other arm of the ring. We indicate that the appearance of the anomalous-non-classical-current circulation results from Fano interference involving localized resonant states. The identification of the Fano interference is based on the comparison of the solution of the scattering problem with the results of the stabilization method. The latter employs the bound-state type calculations and allows us to extract both the energy of metastable states localized within the ring and the width of resonances by analysis of the energy spectrum of a finite size system as a function of its length. The Fano resonances involving states of anomalous current circulation become extremely narrow on both the magnetic field and energy scales. This is consistent with the orientation of the Lorentz force that tends to keep the electron within the ring and thus increases the lifetime of the electron localization within the ring. Absence of periodic Fano resonances in electron transfer probability through a quantum ring containing an elastic scatterer is also explained.
Fernandes, Andrea C; Cloete, Danielle; Broadbent, Matthew T M; Hayes, Richard D; Chang, Chin-Kuo; Jackson, Richard G; Roberts, Angus; Tsang, Jason; Soncul, Murat; Liebscher, Jennifer; Stewart, Robert; Callard, Felicity
2013-07-11
Electronic health records (EHRs) provide enormous potential for health research but also present data governance challenges. Ensuring de-identification is a pre-requisite for use of EHR data without prior consent. The South London and Maudsley NHS Trust (SLaM), one of the largest secondary mental healthcare providers in Europe, has developed, from its EHRs, a de-identified psychiatric case register, the Clinical Record Interactive Search (CRIS), for secondary research. We describe development, implementation and evaluation of a bespoke de-identification algorithm used to create the register. It is designed to create dictionaries using patient identifiers (PIs) entered into dedicated source fields and then identify, match and mask them (with ZZZZZ) when they appear in medical texts. We deemed this approach would be effective, given high coverage of PI in the dedicated fields and the effectiveness of the masking combined with elements of a security model. We conducted two separate performance tests i) to test performance of the algorithm in masking individual true PIs entered in dedicated fields and then found in text (using 500 patient notes) and ii) to compare the performance of the CRIS pattern matching algorithm with a machine learning algorithm, called the MITRE Identification Scrubber Toolkit - MIST (using 70 patient notes - 50 notes to train, 20 notes to test on). We also report any incidences of potential breaches, defined by occurrences of 3 or more true or apparent PIs in the same patient's notes (and in an additional set of longitudinal notes for 50 patients); and we consider the possibility of inferring information despite de-identification. True PIs were masked with 98.8% precision and 97.6% recall. As anticipated, potential PIs did appear, owing to misspellings entered within the EHRs. We found one potential breach. In a separate performance test, with a different set of notes, CRIS yielded 100% precision and 88.5% recall, while MIST yielded a 95.1% and 78.1%, respectively. We discuss how we overcome the realistic possibility - albeit of low probability - of potential breaches through implementation of the security model. CRIS is a de-identified psychiatric database sourced from EHRs, which protects patient anonymity and maximises data available for research. CRIS demonstrates the advantage of combining an effective de-identification algorithm with a carefully designed security model. The paper advances much needed discussion of EHR de-identification - particularly in relation to criteria to assess de-identification, and considering the contexts of de-identified research databases when assessing the risk of breaches of confidential patient information.
Synthesis of nanocrystalline ZnO thin films by electron beam evaporation
NASA Astrophysics Data System (ADS)
Kondkar, V.; Rukade, D.; Bhattacharyya, V.
2018-05-01
Nanocrystalline ZnO thin films have potential for applications in variety of optoelectronic devices. In the present study, nanocrystalline thin films of ZnO are grown on fused silica substrate using electron beam (e-beam) evaporation technique. Phase identification is carried out using Glancing angle X-ray diffraction (GAXRD) and Raman spectroscopy. Ultraviolet-Visible (UV-Vis) spectroscopic analysis is carried out to calculate energy band gap of the ZnO film. Surface morphology of the film is investigated using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). Highly quality nanocrystalline thin films of hexagonal wurtzite ZnO are synthesized using e-beam evaporation technique.
Roda, Barbara; Mirasoli, Mara; Zattoni, Andrea; Casale, Monica; Oliveri, Paolo; Bigi, Alessandro; Reschiglian, Pierluigi; Simoni, Patrizia; Roda, Aldo
2016-10-01
An integrated sensing system is presented for the first time, where a metal oxide semiconductor sensor-based electronic olfactory system (MOS array), employed for pathogen bacteria identification based on their volatile organic compound (VOC) characterisation, is assisted by a preliminary separative technique based on gravitational field-flow fractionation (GrFFF). In the integrated system, a preliminary step using GrFFF fractionation of a complex sample provided bacteria-enriched fractions readily available for subsequent MOS array analysis. The MOS array signals were then analysed employing a chemometric approach using principal components analysis (PCA) for a first-data exploration, followed by linear discriminant analysis (LDA) as a classification tool, using the PCA scores as input variables. The ability of the GrFFF-MOS system to distinguish between viable and non-viable cells of the same strain was demonstrated for the first time, yielding 100 % ability of correct prediction. The integrated system was also applied as a proof of concept for multianalyte purposes, for the detection of two bacterial strains (Escherichia coli O157:H7 and Yersinia enterocolitica) simultaneously present in artificially contaminated milk samples, obtaining a 100 % ability of correct prediction. Acquired results show that GrFFF band slicing before MOS array analysis can significantly increase reliability and reproducibility of pathogen bacteria identification based on their VOC production, simplifying the analytical procedure and largely eliminating sample matrix effects. The developed GrFFF-MOS integrated system can be considered a simple straightforward approach for pathogen bacteria identification directly from their food matrix. Graphical abstract An integrated sensing system is presented for pathogen bacteria identification in food, in which field-flow fractionation is exploited to prepare enriched cell fractions prior to their analysis by electronic olfactory system analysis.
Electron and photon identification in the D0 experiment
DOE Office of Scientific and Technical Information (OSTI.GOV)
Abazov, V. M.; Abbott, B.; Acharya, B. S.
2014-06-01
The electron and photon reconstruction and identification algorithms used by the D0 Collaboration at the Fermilab Tevatron collider are described. The determination of the electron energy scale and resolution is presented. Studies of the performance of the electron and photon reconstruction and identification are summarized.
NASA Astrophysics Data System (ADS)
Woo, S. Y.; Hosseini Vajargah, S.; Ghanad-Tavakoli, S.; Kleiman, R. N.; Botton, G. A.
2012-10-01
Unambiguous identification of anti-phase boundaries (APBs) in heteroepitaxial films of GaSb grown on Si has been so far elusive. In this work, we present conventional transmission electron microscopy (TEM) diffraction contrast imaging using superlattice reflections, in conjunction with convergent beam electron diffraction analysis, to determine a change in polarity across APBs in order to confirm the presence of anti-phase disorder. In-depth analysis of anti-phase disorder is further supported with atomic resolution high-angle annular dark-field scanning transmission electron microscopy. The nature of APBs in GaSb is further elucidated by a comparison to previous results for GaAs epilayers grown on Si.
High Frequency Analyzer (HFA) of Plasma Wave Experiment (PWE) onboard the Arase spacecraft
NASA Astrophysics Data System (ADS)
Kumamoto, Atsushi; Tsuchiya, Fuminori; Kasahara, Yoshiya; Kasaba, Yasumasa; Kojima, Hirotsugu; Yagitani, Satoshi; Ishisaka, Keigo; Imachi, Tomohiko; Ozaki, Mitsunori; Matsuda, Shoya; Shoji, Masafumi; Matsuoka, Aayako; Katoh, Yuto; Miyoshi, Yoshizumi; Obara, Takahiro
2018-05-01
The High Frequency Analyzer (HFA) is a subsystem of the Plasma Wave Experiment onboard the Arase (ERG) spacecraft. The main purposes of the HFA include (1) determining the electron number density around the spacecraft from observations of upper hybrid resonance (UHR) waves, (2) measuring the electromagnetic field component of whistler-mode chorus in a frequency range above 20 kHz, and (3) observing radio and plasma waves excited in the storm-time magnetosphere. Two components of AC electric fields detected by Wire Probe Antenna and one component of AC magnetic fields detected by Magnetic Search Coils are fed to the HFA. By applying analog and digital signal processing in the HFA, the spectrograms of two electric fields (EE mode) or one electric field and one magnetic field (EB mode) in a frequency range from 10 kHz to 10 MHz are obtained at an interval of 8 s. For the observation of plasmapause, the HFA can also be operated in PP (plasmapause) mode, in which spectrograms of one electric field component below 1 MHz are obtained at an interval of 1 s. In the initial HFA operations from January to July, 2017, the following results are obtained: (1) UHR waves, auroral kilometric radiation (AKR), whistler-mode chorus, electrostatic electron cyclotron harmonic waves, and nonthermal terrestrial continuum radiation were observed by the HFA in geomagnetically quiet and disturbed conditions. (2) In the test operations of the polarization observations on June 10, 2017, the fundamental R-X and L-O mode AKR and the second-harmonic R-X mode AKR from different sources in the northern polar region were observed. (3) The semiautomatic UHR frequency identification by the computer and a human operator was applied to the HFA spectrograms. In the identification by the computer, we used an algorithm for narrowing down the candidates of UHR frequency by checking intensity and bandwidth. Then, the identified UHR frequency by the computer was checked and corrected if needed by the human operator. Electron number density derived from the determined UHR frequency will be useful for the investigation of the storm-time evolution of the plasmasphere and topside ionosphere.[Figure not available: see fulltext.
Zhu, Wuming; Trickey, S B
2017-12-28
In high magnetic field calculations, anisotropic Gaussian type orbital (AGTO) basis functions are capable of reconciling the competing demands of the spherically symmetric Coulombic interaction and cylindrical magnetic (B field) confinement. However, the best available a priori procedure for composing highly accurate AGTO sets for atoms in a strong B field [W. Zhu et al., Phys. Rev. A 90, 022504 (2014)] yields very large basis sets. Their size is problematical for use in any calculation with unfavorable computational cost scaling. Here we provide an alternative constructive procedure. It is based upon analysis of the underlying physics of atoms in B fields that allow identification of several principles for the construction of AGTO basis sets. Aided by numerical optimization and parameter fitting, followed by fine tuning of fitting parameters, we devise formulae for generating accurate AGTO basis sets in an arbitrary B field. For the hydrogen iso-electronic sequence, a set depends on B field strength, nuclear charge, and orbital quantum numbers. For multi-electron systems, the basis set formulae also include adjustment to account for orbital occupations. Tests of the new basis sets for atoms H through C (1 ≤ Z ≤ 6) and ions Li + , Be + , and B + , in a wide B field range (0 ≤ B ≤ 2000 a.u.), show an accuracy better than a few μhartree for single-electron systems and a few hundredths to a few mHs for multi-electron atoms. The relative errors are similar for different atoms and ions in a large B field range, from a few to a couple of tens of millionths, thereby confirming rather uniform accuracy across the nuclear charge Z and B field strength values. Residual basis set errors are two to three orders of magnitude smaller than the electronic correlation energies in multi-electron atoms, a signal of the usefulness of the new AGTO basis sets in correlated wavefunction or density functional calculations for atomic and molecular systems in an external strong B field.
NASA Astrophysics Data System (ADS)
Zhu, Wuming; Trickey, S. B.
2017-12-01
In high magnetic field calculations, anisotropic Gaussian type orbital (AGTO) basis functions are capable of reconciling the competing demands of the spherically symmetric Coulombic interaction and cylindrical magnetic (B field) confinement. However, the best available a priori procedure for composing highly accurate AGTO sets for atoms in a strong B field [W. Zhu et al., Phys. Rev. A 90, 022504 (2014)] yields very large basis sets. Their size is problematical for use in any calculation with unfavorable computational cost scaling. Here we provide an alternative constructive procedure. It is based upon analysis of the underlying physics of atoms in B fields that allow identification of several principles for the construction of AGTO basis sets. Aided by numerical optimization and parameter fitting, followed by fine tuning of fitting parameters, we devise formulae for generating accurate AGTO basis sets in an arbitrary B field. For the hydrogen iso-electronic sequence, a set depends on B field strength, nuclear charge, and orbital quantum numbers. For multi-electron systems, the basis set formulae also include adjustment to account for orbital occupations. Tests of the new basis sets for atoms H through C (1 ≤ Z ≤ 6) and ions Li+, Be+, and B+, in a wide B field range (0 ≤ B ≤ 2000 a.u.), show an accuracy better than a few μhartree for single-electron systems and a few hundredths to a few mHs for multi-electron atoms. The relative errors are similar for different atoms and ions in a large B field range, from a few to a couple of tens of millionths, thereby confirming rather uniform accuracy across the nuclear charge Z and B field strength values. Residual basis set errors are two to three orders of magnitude smaller than the electronic correlation energies in multi-electron atoms, a signal of the usefulness of the new AGTO basis sets in correlated wavefunction or density functional calculations for atomic and molecular systems in an external strong B field.
Brodusch, Nicolas; Demers, Hendrix; Trudeau, Michel; Gauvin, Raynald
2013-01-01
Transmission electron forward scatter diffraction (t-EFSD) is a new technique providing crystallographic information with high resolution on thin specimens by using a conventional electron backscatter diffraction (EBSD) system in a scanning electron microscope. In this study, the impact of tilt angle, working distance, and detector distance on the Kikuchi pattern quality were investigated in a cold-field emission scanning electron microscope (CFE-SEM). We demonstrated that t-EFSD is applicable for tilt angles ranging from -20° to -40°. Working distance (WD) should be optimized for each material by choosing the WD for which the EBSD camera screen illumination is the highest, as the number of detected electrons on the screen is directly dependent on the scattering angle. To take advantage of the best performances of the CFE-SEM, the EBSD camera should be close to the sample and oriented towards the bottom to increase forward scattered electron collection efficiency. However, specimen chamber cluttering and beam/mechanical drift are important limitations in the CFE-SEM used in this work. Finally, the importance of t-EFSD in materials science characterization was illustrated through three examples of phase identification and orientation mapping. © Wiley Periodicals, Inc.
NASA Astrophysics Data System (ADS)
Schulze, J.; Donkó, Z.; Lafleur, T.; Wilczek, S.; Brinkmann, R. P.
2018-05-01
Power absorption by electrons from the space- and time-dependent electric field represents the basic sustaining mechanism of all radio-frequency driven plasmas. This complex phenomenon has attracted significant attention. However, most theories and models are, so far, only able to account for part of the relevant mechanisms. The aim of this work is to present an in-depth analysis of the power absorption by electrons, via the use of a moment analysis of the Boltzmann equation without any ad-hoc assumptions. This analysis, for which the input quantities are taken from kinetic, particle based simulations, allows the identification of all physical mechanisms involved and an accurate quantification of their contributions. The perfect agreement between the sum of these contributions and the simulation results verifies the completeness of the model. We study the relative importance of these mechanisms as a function of pressure, with high spatial and temporal resolution, in an electropositive argon discharge. In contrast to some widely accepted previous models we find that high space- and time-dependent ambipolar electric fields outside the sheaths play a key role for electron power absorption. This ambipolar field is time-dependent within the RF period and temporally asymmetric, i.e., the sheath expansion is not a ‘mirror image’ of the sheath collapse. We demonstrate that this time-dependence is mainly caused by a time modulation of the electron temperature resulting from the energy transfer to electrons by the ambipolar field itself during sheath expansion. We provide a theoretical proof that this ambipolar electron power absorption would vanish completely, if the electron temperature was constant in time. This mechanism of electron power absorption is based on a time modulated electron temperature, markedly different from the Hard Wall Model, of key importance for energy transfer to electrons on time average and, thus, essential for the generation of capacitively coupled plasmas.
New Insights into the X-Ray Spectra of Heliumlike and Neonlike Ions
NASA Technical Reports Server (NTRS)
Beiersdorfer, P.; Chen, H.; Hey, D.; Osterheld, A. L.; May, M. J.
2002-01-01
Recent measurements of the K-shell and L-shell x-ray spectra of highly charged helium- like and neonlike ions are presented that were performed on the Livermore electron beam ion traps and the Princeton tokamaks. These measurements provide new insights into collisional and indirect line formation processes, identifications of forbidden lines, and a new plasma line diagnostic of magnetic field strength.
A dual-phase xenon TPC for scintillation and ionisation yield measurements in liquid xenon
NASA Astrophysics Data System (ADS)
Baudis, Laura; Biondi, Yanina; Capelli, Chiara; Galloway, Michelle; Kazama, Shingo; Kish, Alexander; Pakarha, Payam; Piastra, Francesco; Wulf, Julien
2018-05-01
A small-scale, two-phase (liquid/gas) xenon time projection chamber ( Xurich II) was designed, constructed and is under operation at the University of Zürich. Its main purpose is to investigate the microphysics of particle interactions in liquid xenon at energies below 50 keV, which are relevant for rare event searches using xenon as target material. Here we describe in detail the detector, its associated infrastructure, and the signal identification algorithm developed for processing and analysing the data. We present the first characterisation of the new instrument with calibration data from an internal ^83{m} Kr source. The zero-field light yield is 15.0 and 14.0 photoelectrons/keV at 9.4 and 32.1 keV, respectively, and the corresponding values at an electron drift field of 1 kV/cm are 10.8 and 7.9 photoelectrons/keV. The charge yields at these energies are 28 and 31 electrons/keV, with the proportional scintillation yield of 24 photoelectrons per one electron extracted into the gas phase, and an electron lifetime of 200 μ s. The relative energy resolution, σ /E, is 11.9 and 5.8% at 9.4 and 32.1 keV, respectively using a linear combination of the scintillation and ionisation signals. We conclude with measurements of the electron drift velocity at various electric fields, and compare these to literature values.
NASA Astrophysics Data System (ADS)
Chen, Zhangjin; Li, Xiaojin; Sun, Xiaoli; Hao, Xiaolei; Chen, Jing
2017-12-01
We use the semiclassical model to study the intensity dependence of nonsequential double ionization (NSDI) of Ar in short strong laser pulses. The contributions to NSDI through sequential ionization of doubly excited states (SIDE) are identified by tracking the energy trajectories of the two outgoing electrons. The correlated electron momentum distributions are calculated from which the longitudinal momentum distributions of the fast and the slow electrons for the side-by-side and the back-to-back emissions are obtained. The simulated momentum distributions of the fast and the slow electrons for NSDI of Ar by linearly polarized fields with a wavelength of 795 nm at an intensity of 7 × 1013 W cm-2 are in good agreement with the experimental measurements of Liu et al (2014 Phys. Rev. Lett. 112 013003). We demonstrate that the process of double ionization through SIDE dominates NSDI only when the laser intensities are below the recollision threshold; nevertheless, for higher intensities the SIDE process still takes place although the contribution to the NSDI yields decreases rapidly as the intensity increases. It has been found that for SIDE at different intensities, both the correlated electron momentum spectra and the momentum distributions of the fast and the slow electrons remain the same.
Satellite sweeping of electrons at Neptune and Uranus
NASA Technical Reports Server (NTRS)
Cooper, John F.
1990-01-01
Knowledge of satellite sweeping parameters at Neptune and Uranus, and of their functional dependences on particle energy and pitch angle, can be critical in the proper identification of parent absorbers for observed absorption signatures in regions where OTD (offset, tilted dipole) models are valid representations of the measured magnetic fields. In this paper, critical electron energies are calculated for longitudinal drift resonance, snowplow (i.e., strong) absorption, leapfrog, and corkscrew effects, using a reduced version of OTD that neglects nonaxial dipole offsets. Earlier analytic work on sweeping rates is extended to give the radial dependence of these rates within the minimum-L region and to set limits on diffusion of electrons with the simplifying approximation that leapfrog effects are ignored.
Huizing, G; Beckett, A H; Segura, J; Bakke, O M
1980-03-01
1. Electron impact and field desorption mass spectrometry is described and discussed for clebopride, a newly developed benzamide with anti-emetic and anti-dopaminergic properties, and for some related compounds. 2. When clebopride was incubated with liver homogenates of rabbits, 4-amino-5-chloro-2-methoxybenzoic acid and N-(4'-piperidyl)-4-amino-5-chloro-2-methoxybenzamide were identified as metabolites.
2015-09-30
whales that facilitate relatively close approaches to the animals without obviously disturbing them. With this experience, during field projects in... Marine Mammal Electronic Tags” funded through a Science and Technology Transfer (STTR) program Phase II Option 1 contract, Office of Naval Research...assessment: updating photo-identification catalogs for estimating abundance, assessing the nature and extent of fishery interactions with pantropical
Characterization of single grain by observing magnetic ejection and rotation in microgravity
NASA Astrophysics Data System (ADS)
Uyeda, Chiaki
A simple and nondestructive method to perform material identification on a single particle is desired in various fields of material science that is concerned with nano-sized particles. We propose a method of identification based on magnetization data, which is obtained from field-induced translation and rotation in microgravity [1]. Material identification is possible from magnetization data because an intrinsic value of susceptibility and anisotropy is assigned to every material according to a data book that compiles the published values [2]. Preliminary ob-servation on free translational motion due to repulsive field-gradient force was reported for mm-sized crystal of corundum [1] and other oxides. Rotational oscillation was observed for various diamagnetic single-crystals in homogeneous field [2]. In order to examine the capability of the above-mentioned material characterization, translation and rotation motion was observed for sub-millimeter-sized quartz, calcite and forsterite in microgravity condition (MGLAB, Japan, duration: 4.5s). It is expected from motional equations that the 2 motions are independent to mass of particles, In a given field distribution, acceleration of translation is expected to be uniquely determined from intrinsic susceptibility of sample. The above properties are exam-ined in the present work by varying experimental parameters. It is noted that observation of the above two motions in microgravity serve as a useful method to detect magnetization of single small particles, be cause the system is free of both sample holder and mass measure-ment. It is expected that magnetization can be measured on a isolated small sample down to nano-level, in condition that motion of the sample is observable. For both susceptibility and anisotropy, range of observed values using microgravity cover the range of compiled published values [2]. Hence material identification is possible for solid material in general. Diamagnetic magnetization and its anisotropy derive from three-dimensional distribution of localized elec-trons. In case of organic materials, origin of magnetization was consistently explained in terms of molecular-orbital method. The investigation was not performed on oxide crystals partly because the experimental values were not reported for most of the material[4]. Improvement of sensitivity using microgravity condition was necessary in order to understand the overall relationship between electron distribution and anisotropy of susceptibility. [1] K. Hisayoshi et al: J.Phys.: Conf. Ser., (2009) 156 012021. [2] R. Guputa: "Landort Bornstein" New Series II (1983) 445. [3]C.Uyeda et al.(206)Jpn.J.appl.Phys.43 L124 [4]C.Uyeda et al.: Appl. Phys. Lett. (1983) 094103.
NASA Astrophysics Data System (ADS)
Iafrate, G. J.; Sokolov, V. N.; Krieger, J. B.
2017-10-01
The theory of Bloch electron dynamics for carriers in homogeneous electric and magnetic fields of arbitrary time dependence is developed in the framework of the Liouville equation. The Wigner distribution function (WDF) is determined from the single-particle density matrix in the ballistic regime, i.e., collision effects are excluded. In the theory, the single-particle transport equation is established with the electric field described in the vector potential gauge, and the magnetic field is treated in the symmetric gauge. No specific assumptions are made concerning the form of the initial distribution in momentum or configuration space. The general approach is to employ the accelerated Bloch state representation (ABR) as a basis so that the dependence upon the electric field, including multiband Zener tunneling, is treated exactly. Further, in the formulation of the WDF, we transform to a new set of variables so that the final WDF is gauge invariant and is expressed explicitly in terms of the position, kinetic momentum, and time. The methodology for developing the WDF is illustrated by deriving the exact WDF equation for free electrons in homogeneous electric and magnetic fields resulting in the same form as given by the collisionless Boltzmann transport equation (BTE). The methodology is then extended to the case of electrons described by an effective Hamiltonian corresponding to an arbitrary energy band function; the exact WDF equation results for the effective Hamiltonian case are shown to approximate the free electron results when taken to second order in the magnetic field. As a corollary, in these cases, it is shown that if the WDF is a wave packet, then the time rate of change of the electron quasimomentum is given by the Lorentz force. In treating the problem of Bloch electrons in a periodic potential in the presence of homogeneous electric and magnetic fields, the methodology for deriving the WDF reveals a multiband character due to the inherent nature of the Bloch states. The K0 representation of the Bloch envelope functions is employed to express the multiband WDF in a useful form. In examining the single-band WDF, it is found that the collisionless WDF equation matches the equivalent BTE to first order in the magnetic field. These results are necessarily extended to second order in the magnetic field by employing a unitary transformation that diagonalizes the Hamiltonian using the ABR to second order. The unitary transformation process includes a discussion of the multiband WDF transport analysis and the identification of the combined Zener-magnetic-field induced tunneling.
Layton, Danielle M; Clarke, Michael
2016-01-01
To review how articles are retrieved from bibliographic databases, what article identification and translation problems have affected research, and how these problems can contribute to research waste and affect clinical practice. This literature review sought and appraised articles regarding identification- and translation-bias in the medical and dental literature, which limit the ability of users to find research articles and to use these in practice. Articles can be retrieved from bibliographic databases by performing a word or index-term (for example, MeSH for MEDLINE) search. Identification of articles is challenging when it is not clear which words are most relevant, and which terms have been allocated to indexing fields. Poor reporting quality of abstracts and articles has been reported across the medical literature at large. Specifically in dentistry, research regarding time-to-event survival analyses found the allocation of MeSH terms to be inconsistent and inaccurate, important words were omitted from abstracts by authors, and the quality of reporting in the body of articles was generally poor. These shortcomings mean that articles will be difficult to identify, and difficult to understand if found. Use of specialized electronic search strategies can decrease identification bias, and use of tailored reporting guidelines can decrease translation bias. Research that cannot be found, or cannot be used results in research waste, and undermines clinical practice. Identification- and translation-bias have been shown to affect time-to-event dental articles, are likely affect other fields of research, and are largely unrecognized by authors and evidence seekers alike. By understanding that the problems exist, solutions can be sought to improve identification and translation of our research. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Murzakhanov, F.; Mamin, G.; Voloshin, A.; Klimashina, E.; Putlyaev, V.; Doronin, V.; Bakhteev, S.; Yusupov, R.; Gafurov, M.; Orlinskii, S.
2018-05-01
Powders of synthetic hydroxyapatite doped with Mn2+ ions in concentrations from 0.05 till 5 wt. % were investigated by conventional electron paramagnetic resonance (EPR). The parameters of the spin-Hamiltonian are derived. Partially resolved hyperfine structure in the magnetic fields corresponding to g ≈ 4.3 and g ≈ 9.4 is observed. The narrowing of the central peak with concentration is reported. A possibility to use the linewidth and intensity of the central peak for concentration measurements are discussed. The results could be used for the identification and qualification of Mn2+ in oil, mining and ore formations.
NASA Technical Reports Server (NTRS)
Wernet, Mark P.; Pline, Alexander D.
1991-01-01
The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electronic, two-dimensional particle image velocimetry technique called particle displacement tracking (PDT) which uses a simple space domain particle tracking algorithm. The PDT system is successful in producing velocity vector fields from the raw video data. Application of the PDT technique to a sample data set yielded 1606 vectors in 30 seconds of processing time. A bottom viewing optical arrangement is used to image the illuminated plane, which causes keystone distortion in the final recorded image. A coordinate transformation was incorporated into the system software to correct this viewing angle distortion. PDT processing produced 1.8 percent false identifications, due to random particle locations. A highly successful routine for removing the false identifications was also incorporated, reducing the number of false identifications to 0.2 percent.
NASA Technical Reports Server (NTRS)
Wernet, Mark P.; Pline, Alexander D.
1991-01-01
The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electronic, two-dimensional particle image velocimetry technique called particle displacement tracking (PDT) which uses a simple space domain particle tracking algorithm. The PDT system is successful in producing velocity vector fields from the raw video data. Application of the PDT technique to a sample data set yielded 1606 vectors in 30 seconds of processing time. A bottom viewing optical arrangement is used to image the illuminated plane, which causes keystone distortion in the final recorded image. A coordinate transformation was incorporated into the system software to correct this viewing angle distortion. PDT processing produced 1.8 percent false identifications, due to random particle locations. A highly successful routine for removing the false identifications was also incorporated, reducing the number of false identifications to 0.2 percent.
Martin, Todd M
2017-05-01
The goal of alternatives assessment (AA) is to facilitate a comparison of alternatives to a chemical of concern, resulting in the identification of safer alternatives. A two stage methodology for comparing chemical alternatives was developed. In the first stage, alternatives are compared using a variety of human health effects, ecotoxicity, and physicochemical properties. Hazard profiles are completed using a variety of online sources and quantitative structure activity relationship models. In the second stage, alternatives are evaluated utilizing an exposure/risk assessment over the entire life cycle. Exposure values are calculated using screening-level near-field and far-field exposure models. The second stage allows one to more accurately compare potential exposure to each alternative and consider additional factors that may not be obvious from separate binned persistence, bioaccumulation, and toxicity scores. The methodology was utilized to compare phosphate-based alternatives for decabromodiphenyl ether (decaBDE) in electronics applications.
NASA Technical Reports Server (NTRS)
Mikellides, Ioannis G.; Katz, Ira; Goebel, Dan M.; Jameson, Kristina K.
2006-01-01
Numerical simulations with the time-dependent Orificed Cathode (OrCa2D-II) computer code show that classical enhancements of the plasma resistivity can not account for the elevated electron temperatures and steep plasma potential gradients measured in the plume of a 25-27.5 A discharge hollow cathode. The cathode, which employs a 0.11-in diameter orifice, was operated at 5.5 sccm without an applied magnetic field using two different anode geometries. It is found that anomalous resistivity based on electron-driven instabilities improves the comparison between theory and experiment. It is also estimated that other effects such as the Hall-effect from the self-induced magnetic field, not presently included in OrCa2D-II, may contribute to the constriction of the current density streamlines thus explaining the higher plasma densities observed along the centerline.
Shimojima, Takahiro; Malaeb, Walid; Nakamura, Asuka; Kondo, Takeshi; Kihou, Kunihiro; Lee, Chul-Ho; Iyo, Akira; Eisaki, Hiroshi; Ishida, Shigeyuki; Nakajima, Masamichi; Uchida, Shin-ichi; Ohgushi, Kenya; Ishizaka, Kyoko; Shin, Shik
2017-01-01
A major problem in the field of high-transition temperature (Tc) superconductivity is the identification of the electronic instabilities near superconductivity. It is known that the iron-based superconductors exhibit antiferromagnetic order, which competes with the superconductivity. However, in the nonmagnetic state, there are many aspects of the electronic instabilities that remain unclarified, as represented by the orbital instability and several in-plane anisotropic physical properties. We report a new aspect of the electronic state of the optimally doped iron-based superconductors by using high–energy resolution angle-resolved photoemission spectroscopy. We find spectral evidence for the folded electronic structure suggestive of an antiferroic electronic instability, coexisting with the superconductivity in the nonmagnetic state of Ba1−xKxFe2As2. We further establish a phase diagram showing that the antiferroic electronic structure persists in a large portion of the nonmagnetic phase covering the superconducting dome. These results motivate consideration of a key unknown electronic instability, which is necessary for the achievement of high-Tc superconductivity in the iron-based superconductors. PMID:28875162
Shimojima, Takahiro; Malaeb, Walid; Nakamura, Asuka; Kondo, Takeshi; Kihou, Kunihiro; Lee, Chul-Ho; Iyo, Akira; Eisaki, Hiroshi; Ishida, Shigeyuki; Nakajima, Masamichi; Uchida, Shin-Ichi; Ohgushi, Kenya; Ishizaka, Kyoko; Shin, Shik
2017-08-01
A major problem in the field of high-transition temperature ( T c ) superconductivity is the identification of the electronic instabilities near superconductivity. It is known that the iron-based superconductors exhibit antiferromagnetic order, which competes with the superconductivity. However, in the nonmagnetic state, there are many aspects of the electronic instabilities that remain unclarified, as represented by the orbital instability and several in-plane anisotropic physical properties. We report a new aspect of the electronic state of the optimally doped iron-based superconductors by using high-energy resolution angle-resolved photoemission spectroscopy. We find spectral evidence for the folded electronic structure suggestive of an antiferroic electronic instability, coexisting with the superconductivity in the nonmagnetic state of Ba 1- x K x Fe 2 As 2 . We further establish a phase diagram showing that the antiferroic electronic structure persists in a large portion of the nonmagnetic phase covering the superconducting dome. These results motivate consideration of a key unknown electronic instability, which is necessary for the achievement of high- T c superconductivity in the iron-based superconductors.
Visualization of Hierarchical Nanodomains in Polymer/Fullerene Bulk Heterojunction Solar Cells
Wen, Jianguo; Miller, Dean J.; Chen, Wei; ...
2014-06-20
Here, traditional electron microscopy techniques such as bright-field imaging provide poor contrast for organic films and identification of structures in amorphous material can be problematic, particularly in high-performance organic solar cells. By combining energy-filtered corrected transmission electron microscopy, together with electron energy loss and X-ray energy-dispersive hyperspectral imaging, we have imaged PTB7/ PC 61BM blended polymer optical photovoltaic films, and were able to identify domains ranging in size from several hundred nanometers to several nanometers in extent. This work verifies that microstructural domains exist in bulk heterojunctions in PTB7/PC 61BM polymeric solar cells at multiple length scales and expands ourmore » understanding of optimal device performance providing insight for the design of even higher performance cells.« less
A pragmatics' view of patient identification.
Lichtner, Valentina; Galliers, Julia R; Wilson, Stephanie
2010-10-01
Patient identification is a central safety critical aspect of healthcare work. Most healthcare activities require identification of patients by healthcare staff, often in connection with the use of patient records. Indeed, the increasing reliance on electronic systems makes the correct matching of patients with their records a keystone for patient safety. Most research on patient identification has been carried out in hospital settings. The aim was to investigate the process of identification of patients and their records in the context of a primary healthcare clinic. A qualitative field study was carried out at a Walk-In Centre in London (UK). The identification of patients and their records was found to be a context-dependent process, both when formalised in procedures and when relying on informal practices. The authors discovered a range of formal and informal patient identifiers were used in this setting, depending on the task at hand. The theoretical lens of Pragmatics was applied to offer an explanation of this identification process. Context provides the cognitive scaffolding for a process of 'suitably constrained guesswork' about the identity of patients and their records. Implications for practice and for system design are discussed. Practitioners and technology designers should be aware of the risk for misidentifications inherent in this natural information processing activity.
Investigation of outside visual cues required for low speed and hover
NASA Technical Reports Server (NTRS)
Hoh, R. H.
1985-01-01
Knowledge of the visual cues required in the performance of stabilized hover in VTOL aircraft is a prerequisite for the development of both cockpit displays and ground-based simulation systems. Attention is presently given to the viability of experimental test flight techniques as the bases for the identification of essential external cues in aggressive and precise low speed and hovering tasks. The analysis and flight test program conducted employed a helicopter and a pilot wearing lenses that could be electronically fogged, where the primary variables were field-of-view, large object 'macrotexture', and fine detail 'microtexture', in six different fields-of-view. Fundamental metrics are proposed for the quantification of the visual field, to allow comparisons between tests, simulations, and aircraft displays.
Charge sniffer for electrostatics demonstrations
NASA Astrophysics Data System (ADS)
Dinca, Mihai P.
2011-02-01
An electronic electroscope with a special design for demonstrations and experiments on static electricity is described. It operates as an electric charge sniffer by detecting slightly charged objects when they are brought to the front of its sensing electrode. The sniffer has the advantage of combining high directional sensitivity with a logarithmic bar display. It allows for the identification of electric charge polarity during charge separation by friction, peeling, electrostatic induction, batteries, or secondary coils of power transformers. Other experiments in electrostatics, such as observing the electric field of an oscillating dipole and the distance dependence of the electric field generated by simple charge configurations, are also described.
NASA Technical Reports Server (NTRS)
Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.
1981-01-01
Steady-state, total-dose radiation test data are provided in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. Data are presented by JPL for various NASA space programs on diodes, bipolar transistors, field effect transistors, silicon-controlled rectifiers, and optical devices. A vendor identification code list is included along with semiconductor device electrical parameter symbols and abbreviations.
Individual identification via electrocardiogram analysis.
Fratini, Antonio; Sansone, Mario; Bifulco, Paolo; Cesarelli, Mario
2015-08-14
During last decade the use of ECG recordings in biometric recognition studies has increased. ECG characteristics made it suitable for subject identification: it is unique, present in all living individuals, and hard to forge. However, in spite of the great number of approaches found in literature, no agreement exists on the most appropriate methodology. This study aimed at providing a survey of the techniques used so far in ECG-based human identification. Specifically, a pattern recognition perspective is here proposed providing a unifying framework to appreciate previous studies and, hopefully, guide future research. We searched for papers on the subject from the earliest available date using relevant electronic databases (Medline, IEEEXplore, Scopus, and Web of Knowledge). The following terms were used in different combinations: electrocardiogram, ECG, human identification, biometric, authentication and individual variability. The electronic sources were last searched on 1st March 2015. In our selection we included published research on peer-reviewed journals, books chapters and conferences proceedings. The search was performed for English language documents. 100 pertinent papers were found. Number of subjects involved in the journal studies ranges from 10 to 502, age from 16 to 86, male and female subjects are generally present. Number of analysed leads varies as well as the recording conditions. Identification performance differs widely as well as verification rate. Many studies refer to publicly available databases (Physionet ECG databases repository) while others rely on proprietary recordings making difficult them to compare. As a measure of overall accuracy we computed a weighted average of the identification rate and equal error rate in authentication scenarios. Identification rate resulted equal to 94.95 % while the equal error rate equal to 0.92 %. Biometric recognition is a mature field of research. Nevertheless, the use of physiological signals features, such as the ECG traits, needs further improvements. ECG features have the potential to be used in daily activities such as access control and patient handling as well as in wearable electronics applications. However, some barriers still limit its growth. Further analysis should be addressed on the use of single lead recordings and the study of features which are not dependent on the recording sites (e.g. fingers, hand palms). Moreover, it is expected that new techniques will be developed using fiducials and non-fiducial based features in order to catch the best of both approaches. ECG recognition in pathological subjects is also worth of additional investigations.
Millimeter wave sensor requirements for maritime small craft identification
NASA Astrophysics Data System (ADS)
Krapels, Keith; Driggers, Ronald G.; Garcia, Jose; Boettcher, Evelyn; Prather, Dennis; Schuetz, Chrisopher; Samluk, Jesse; Stein, Lee; Kiser, William; Visnansky, Andrew; Grata, Jeremy; Wikner, David; Harris, Russ
2009-09-01
Passive millimeter wave (mmW) imagers have improved in terms of resolution sensitivity and frame rate. Currently, the Office of Naval Research (ONR), along with the US Army Research, Development and Engineering Command, Communications Electronics Research Development and Engineering Center (RDECOM CERDEC) Night Vision and Electronic Sensor Directorate (NVESD), are investigating the current state-of-the-art of mmW imaging systems. The focus of this study was the performance of mmW imaging systems for the task of small watercraft / boat identification field performance. First mmW signatures were collected. This consisted of a set of eight small watercrafts; at 5 different aspects, during the daylight hours over a 48 hour period in the spring of 2008. Target characteristics were measured and characteristic dimension, signatures, and Root Sum Squared of Target's Temperature (RRSΔT) tabulated. Then an eight-alternative, forced choice (8AFC) human perception experiment was developed and conducted at NVESD. The ability of observers to discriminate between small watercraft was quantified. Next, the task difficulty criterion, V50, was quantified by applying this data to NVESD's target acquisition models using the Targeting Task Performance (TTP) metric. These parameters can be used to evaluate sensor field performance for Anti-Terrorism / Force Protection (AT/FP) and navigation tasks for the U.S. Navy, as well as for design and evaluation of imaging passive mmW sensors for both the U.S. Navy and U.S. Coast Guard.
Two-dimensional strain-mapping by electron backscatter diffraction and confocal Raman spectroscopy
NASA Astrophysics Data System (ADS)
Gayle, Andrew J.; Friedman, Lawrence H.; Beams, Ryan; Bush, Brian G.; Gerbig, Yvonne B.; Michaels, Chris A.; Vaudin, Mark D.; Cook, Robert F.
2017-11-01
The strain field surrounding a spherical indentation in silicon is mapped in two dimensions (2-D) using electron backscatter diffraction (EBSD) cross-correlation and confocal Raman spectroscopy techniques. The 200 mN indentation created a 4 μm diameter residual contact impression in the silicon (001) surface. Maps about 50 μm × 50 μm area with 128 pixels × 128 pixels were generated in several hours, extending, by comparison, assessment of the accuracy of both techniques to mapping multiaxial strain states in 2-D. EBSD measurements showed a residual strain field dominated by in-surface normal and shear strains, with alternating tensile and compressive lobes extending about three to four indentation diameters from the contact and exhibiting two-fold symmetry. Raman measurements showed a residual Raman shift field, dominated by positive shifts, also extending about three to four indentation diameters from the contact but exhibiting four-fold symmetry. The 2-D EBSD results, in combination with a mechanical-spectroscopic analysis, were used to successfully predict the 2-D Raman shift map in scale, symmetry, and shift magnitude. Both techniques should be useful in enhancing the reliability of microelectromechanical systems (MEMS) through identification of the 2-D strain fields in MEMS devices.
Zhou, Yangbo; Fox, Daniel S; Maguire, Pierce; O’Connell, Robert; Masters, Robert; Rodenburg, Cornelia; Wu, Hanchun; Dapor, Maurizio; Chen, Ying; Zhang, Hongzhou
2016-01-01
Two-dimensional (2D) materials usually have a layer-dependent work function, which require fast and accurate detection for the evaluation of their device performance. A detection technique with high throughput and high spatial resolution has not yet been explored. Using a scanning electron microscope, we have developed and implemented a quantitative analytical technique which allows effective extraction of the work function of graphene. This technique uses the secondary electron contrast and has nanometre-resolved layer information. The measurement of few-layer graphene flakes shows the variation of work function between graphene layers with a precision of less than 10 meV. It is expected that this technique will prove extremely useful for researchers in a broad range of fields due to its revolutionary throughput and accuracy. PMID:26878907
Detection of chemical warfare simulants using Raman excitation at 1064 nm
NASA Astrophysics Data System (ADS)
Dentinger, Claire; Mabry, Mark W.; Roy, Eric G.
2014-05-01
Raman spectroscopy is a powerful technique for material identification. The technique is sensitive to primary and higher ordered molecular structure and can be used to identify unknown materials by comparison with spectral reference libraries. Additionally, miniaturization of opto-electronic components has permitted development of portable Raman analyzers that are field deployable. Raman scattering is a relatively weak effect compared to a competing phenomenon, fluorescence. Even a moderate amount of fluorescence background interference can easily prevent identification of unknown materials. A long wavelength Raman system is less likely to induce fluorescence from a wider variety of materials than a higher energy visible laser system. Compounds such as methyl salicylate (MS), diethyl malonate (DEM), and dimethyl methylphosphonate (DMMP) are used as chemical warfare agent (CWA) simulants for development of analytical detection strategies. Field detection of these simulants however poses unique challenges because threat identification must be made quickly without the turnaround time usually required for a laboratory based analysis. Fortunately, these CWA simulants are good Raman scatterers, and field based detection using portable Raman instruments is promising. Measurements of the CWA simulants were done using a 1064 nm based portable Raman spectrometer. The longer wavelength excitation laser was chosen relative to a visible based laser systems because the 1064 nm based spectrometer is less likely to induce fluorescence and more suitable to a wider range of materials. To more closely mimic real world measurement situations, different sample presentations were investigated.
Code of Federal Regulations, 2014 CFR
2014-10-01
... Electronic Office Equipment Providing Accessibility for the Handicapped. 552.238-70 Section 552.238-70... Equipment Providing Accessibility for the Handicapped. As prescribed in 538.273(a)(1), insert the following clause: Identification of Electronic Office Equipment Providing Accessibility for the Handicapped (SEP...
Code of Federal Regulations, 2013 CFR
2013-10-01
... Electronic Office Equipment Providing Accessibility for the Handicapped. 552.238-70 Section 552.238-70... Equipment Providing Accessibility for the Handicapped. As prescribed in 538.273(a)(1), insert the following clause: Identification of Electronic Office Equipment Providing Accessibility for the Handicapped (SEP...
Code of Federal Regulations, 2010 CFR
2010-10-01
... Electronic Office Equipment Providing Accessibility for the Handicapped. 552.238-70 Section 552.238-70... Equipment Providing Accessibility for the Handicapped. As prescribed in 538.273(a)(1), insert the following clause: Identification of Electronic Office Equipment Providing Accessibility for the Handicapped (SEP...
Code of Federal Regulations, 2012 CFR
2012-10-01
... Electronic Office Equipment Providing Accessibility for the Handicapped. 552.238-70 Section 552.238-70... Equipment Providing Accessibility for the Handicapped. As prescribed in 538.273(a)(1), insert the following clause: Identification of Electronic Office Equipment Providing Accessibility for the Handicapped (SEP...
Code of Federal Regulations, 2011 CFR
2011-10-01
... Electronic Office Equipment Providing Accessibility for the Handicapped. 552.238-70 Section 552.238-70... Equipment Providing Accessibility for the Handicapped. As prescribed in 538.273(a)(1), insert the following clause: Identification of Electronic Office Equipment Providing Accessibility for the Handicapped (SEP...
21 CFR 11.300 - Controls for identification codes/passwords.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Controls for identification codes/passwords. 11.300 Section 11.300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ELECTRONIC RECORDS; ELECTRONIC SIGNATURES Electronic Signatures § 11.300 Controls for...
NASA Technical Reports Server (NTRS)
Stroke, G. W.
1972-01-01
Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.
True-sky demonstration of an autonomous star tracker
NASA Astrophysics Data System (ADS)
van Bezooijen, Roelof W.
1994-07-01
An autonomous star tracker (AST) is basically a `star field in, attitude out' device capable of determining its attitude without requiring any a priori attitude knowledge. In addition to this attitude acquisition capability, an AST can perform attitude updates autonomously and is able to provide its attitude `continuously' while tracking a star field. The Lockheed Palo Alto Research Laboratory is developing a reliable, low-cost, miniature AST that has a one arcsec overall accuracy, weighs less than 1.5 kg, consumes less than 7 watts of power, and is sufficiently sensitive to be used at all sky locations. The device performs attitude acquisition in a fraction of a second and outputs its attitude at a 10 Hz rate when operating in its tracking mode. Besides providing the functionality needed for future advanced attitude control and navigation systems, an AST also improves spacecraft reliability, mass, power, cost, and operating expenses. The AST comprises a-thermalized, refractive optics, a frame-transfer CCD with a sensitive area of 1024 by 1024 pixels, camera electronics implemented with application- specific integrated circuits, a compact single board computer with a radiation hard 32 bit RISC processor, and an all-sky guide star database. Star identification is performed by a memory- efficient and highly robust algorithm that finds the largest group of observed stars matching a group of guide stars. An important milestone has recently been achieved with the validation of the attitude acquisition capability through correct and rapid identification of all 704 true-sky star fields obtained at the Lick Observatory, using an uncalibrated prototype AST with a 512 by 1024 pixel frame-transfer CCD and a 50 mm f/1.2 lens that provided an effective 6.5 by 13.2 degree field of view. The overlapping fields cover 47% of the sky, including both rich and sparse areas. The paper contains a description of the AST, a summary of the functions enabled or improved by the device, an overview of the identification algorithm, results obtained with a realistic simulation program, a description of the true-sky star field identification method and a presentation of the results obtained. The AST tolerates the presence of bright objects as was demonstrated by a field that included Jupiter.
Identification of insecticide residues with a conducting-polymer electronic nose
A.D. Wilson
2014-01-01
The identification of insecticide residues on crop foliage is needed to make periodic pest management decisions. Electronic-nose (e-nose) methods were developed and tested as a means of acquiring rapid identifications of insecticide residue types at relatively low cost by detection of headspace volatiles released from inert surfaces in vitro. Detection methods were...
Martin, Todd M.
2017-01-01
The goal of alternatives assessment (AA) is to facilitate a comparison of alternatives to a chemical of concern, resulting in the identification of safer alternatives. A two stage methodology for comparing chemical alternatives was developed. In the first stage, alternatives are compared using a variety of human health effects, ecotoxicity, and physicochemical properties. Hazard profiles are completed using a variety of online sources and quantitative structure activity relationship models. In the second stage, alternatives are evaluated utilizing an exposure/risk assessment over the entire life cycle. Exposure values are calculated using screening-level near-field and far-field exposure models. The second stage allows one to more accurately compare potential exposure to each alternative and consider additional factors that may not be obvious from separate binned persistence, bioaccumulation, and toxicity scores. The methodology was utilized to compare phosphate-based alternatives for decabromodiphenyl ether (decaBDE) in electronics applications. PMID:29333139
Wheeze sound analysis using computer-based techniques: a systematic review.
Ghulam Nabi, Fizza; Sundaraj, Kenneth; Chee Kiang, Lam; Palaniappan, Rajkumar; Sundaraj, Sebastian
2017-10-31
Wheezes are high pitched continuous respiratory acoustic sounds which are produced as a result of airway obstruction. Computer-based analyses of wheeze signals have been extensively used for parametric analysis, spectral analysis, identification of airway obstruction, feature extraction and diseases or pathology classification. While this area is currently an active field of research, the available literature has not yet been reviewed. This systematic review identified articles describing wheeze analyses using computer-based techniques on the SCOPUS, IEEE Xplore, ACM, PubMed and Springer and Elsevier electronic databases. After a set of selection criteria was applied, 41 articles were selected for detailed analysis. The findings reveal that 1) computerized wheeze analysis can be used for the identification of disease severity level or pathology, 2) further research is required to achieve acceptable rates of identification on the degree of airway obstruction with normal breathing, 3) analysis using combinations of features and on subgroups of the respiratory cycle has provided a pathway to classify various diseases or pathology that stem from airway obstruction.
Li, Jie; He, Yujun; Han, Yimo; Liu, Kai; Wang, Jiaping; Li, Qunqing; Fan, Shoushan; Jiang, Kaili
2012-08-08
Because of their excellent electrical and optical properties, carbon nanotubes have been regarded as extremely promising candidates for high-performance electronic and optoelectronic applications. However, effective and efficient distinction and separation of metallic and semiconducting single-walled carbon nanotubes are always challenges for their practical applications. Here we show that metallic and semiconducting single-walled carbon nanotubes on SiO(2) can have obviously different contrast in scanning electron microscopy due to their conductivity difference and thus can be effectively and efficiently identified. The correlation between conductivity and contrast difference has been confirmed by using voltage-contrast scanning electron microcopy, peak force tunneling atom force microscopy, and field effect transistor testing. This phenomenon can be understood via a proposed mechanism involving the e-beam-induced surface potential of insulators and the conductivity difference between metallic and semiconducting SWCNTs. This method demonstrates great promise to achieve rapid and large-scale distinguishing between metallic and semiconducting single-walled carbon nanotubes, adding a new function to conventional SEM.
Xiao, Cong; Li, Dingping
2016-06-15
Semiclassical magnetoelectric and magnetothermoelectric transport in strongly spin-orbit coupled Rashba two-dimensional electron systems is investigated. In the presence of a perpendicular classically weak magnetic field and short-range impurity scattering, we solve the linearized Boltzmann equation self-consistently. Using the solution, it is found that when Fermi energy E F locates below the band crossing point (BCP), the Hall coefficient is a nonmonotonic function of electron density n e and not inversely proportional to n e. While the magnetoresistance (MR) and Nernst coefficient vanish when E F locates above the BCP, non-zero MR and enhanced Nernst coefficient emerge when E F decreases below the BCP. Both of them are nonmonotonic functions of E F below the BCP. The different semiclassical magnetotransport behaviors between the two sides of the BCP can be helpful to experimental identifications of the band valley regime and topological change of Fermi surface in considered systems.
NASA Astrophysics Data System (ADS)
Xiao, Cong; Li, Dingping
2016-06-01
Semiclassical magnetoelectric and magnetothermoelectric transport in strongly spin-orbit coupled Rashba two-dimensional electron systems is investigated. In the presence of a perpendicular classically weak magnetic field and short-range impurity scattering, we solve the linearized Boltzmann equation self-consistently. Using the solution, it is found that when Fermi energy E F locates below the band crossing point (BCP), the Hall coefficient is a nonmonotonic function of electron density n e and not inversely proportional to n e. While the magnetoresistance (MR) and Nernst coefficient vanish when E F locates above the BCP, non-zero MR and enhanced Nernst coefficient emerge when E F decreases below the BCP. Both of them are nonmonotonic functions of E F below the BCP. The different semiclassical magnetotransport behaviors between the two sides of the BCP can be helpful to experimental identifications of the band valley regime and topological change of Fermi surface in considered systems.
Finite-element 3D simulation tools for high-current relativistic electron beams
NASA Astrophysics Data System (ADS)
Humphries, Stanley; Ekdahl, Carl
2002-08-01
The DARHT second-axis injector is a challenge for computer simulations. Electrons are subject to strong beam-generated forces. The fields are fully three-dimensional and accurate calculations at surfaces are critical. We describe methods applied in OmniTrak, a 3D finite-element code suite that can address DARHT and the full range of charged-particle devices. The system handles mesh generation, electrostatics, magnetostatics and self-consistent particle orbits. The MetaMesh program generates meshes of conformal hexahedrons to fit any user geometry. The code has the unique ability to create structured conformal meshes with cubic logic. Organized meshes offer advantages in speed and memory utilization in the orbit and field solutions. OmniTrak is a versatile charged-particle code that handles 3D electric and magnetic field solutions on independent meshes. The program can update both 3D field solutions from the calculated beam space-charge and current-density. We shall describe numerical methods for orbit tracking on a hexahedron mesh. Topics include: 1) identification of elements along the particle trajectory, 2) fast searches and adaptive field calculations, 3) interpolation methods to terminate orbits on material surfaces, 4) automatic particle generation on multiple emission surfaces to model space-charge-limited emission and field emission, 5) flexible Child law algorithms, 6) implementation of the dual potential model for 3D magnetostatics, and 7) assignment of charge and current from model particle orbits for self-consistent fields.
NASA Astrophysics Data System (ADS)
Renner, J.; Cervera, A.; Hernando, J. A.; Imzaylov, A.; Monrabal, F.; Muñoz, J.; Nygren, D.; Gomez-Cadenas, J. J.
2015-12-01
We demonstrate that the application of an external magnetic field could lead to an improved background rejection in neutrinoless double-beta (0νββ) decay experiments using a high-pressure xenon (HPXe) TPC. HPXe chambers are capable of imaging electron tracks, a feature that enhances the separation between signal events (the two electrons emitted in the 0νββ decay of 136Xe) and background events, arising chiefly from single electrons of kinetic energy compatible with the end-point of the 0νββ decay (0Qββ). Applying an external magnetic field of sufficiently high intensity (in the range of 0.5-1 Tesla for operating pressures in the range of 5-15 atmospheres) causes the electrons to produce helical tracks. Assuming the tracks can be properly reconstructed, the sign of the curvature can be determined at several points along these tracks, and such information can be used to separate signal (0νββ) events containing two electrons producing a track with two different directions of curvature from background (single-electron) events producing a track that should spiral in a single direction. Due to electron multiple scattering, this strategy is not perfectly efficient on an event-by-event basis, but a statistical estimator can be constructed which can be used to reject background events by one order of magnitude at a moderate cost (about 30%) in signal efficiency. Combining this estimator with the excellent energy resolution and topological signature identification characteristic of the HPXe TPC, it is possible to reach a background rate of less than one count per ton-year of exposure. Such a low background rate is an essential feature of the next generation of 0νββ experiments, aiming to fully explore the inverse hierarchy of neutrino masses.
Brace, L H; Theis, R F; Krehbiel, J P; Nagy, A F; Donahue, T M; McElroy, M B; Pedersen, A
1979-02-23
Altitude profiles of electron temperature and density in the ionosphere of Venus have been obtained by the Pioneer Venus orbiter electron temperatutre probe. Elevated temperatutres observed at times of low solar wind flux exhibit height profiles that are consistent with a model in which less than 5 percent of the solar wind energy is deposited at the ionopause and is conducted downward through an unmagnetized ionosphere to the region below 200 kilomneters where electron cooling to the neutral atmosphere proceeds rapidly. When solar wind fluxes are higher, the electron temperatures and densities are highly structured and the ionopause moves to lower altitudes. The ionopause height in the late afternoon sector observed thus far varies so widely from day to (day that any height variation with solar zenith angle is not apparent in the observations. In the neighborhood of the ionopause, measuremnents of plasma temperatures and densities and magnetic field strength indicate that an induced magnetic barrier plays an important role in the pressure transfer between the solar wind and the ionosphere. The bow, shock is marked by a distinct increase in electron current collected by the instrument, a featutre that provides a convenient identification of the bow shock location.
Houliston, Bryan; Parry, David; Webster, Craig S; Merry, Alan F
2009-06-19
To replicate electromagnetic interference (EMI) with a common drug infusion device resulting from the use of radio frequency identification (RFID) technology in a simulated operating theatre environment. An infusion pump, of a type previously reported as having failed due to RFID EMI, was placed in radio frequency (RF) fields of various strengths, and its operation observed. Different strength RF fields were created by varying the number of RFID readers, the use of a high-gain RFID antenna, the distance between the reader(s) and the infusion pump, and the presence of an RFID tag on the infusion pump. The infusion pump was not affected by low-power RFID readers, even when in direct contact. The pump was disrupted by a high-power reader at 10 cm distance when an RFID tag was attached, and by a combination of high-power and low-power readers at 10 cm distance. Electronic medical devices may fail in the presence of high-power RFID readers, especially if the device is tagged. However, low-power RFID readers appear to be safer.
Electromagnetic Test-Facility characterization: an identification approach
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zicker, J.E.; Candy, J.V.
The response of an object subjected to high energy, transient electromagnetic (EM) fields sometimes called electromagnetic pulses (EMP), is an important issue in the survivability of electronic systems (e.g., aircraft), especially when the field has been generated by a high altitude nuclear burst. The characterization of transient response information is a matter of national concern. In this report we discuss techniques to: (1) improve signal processing at a test facility; and (2) parameterize a particular object response. First, we discuss the application of identification-based signal processing techniques to improve signal levels at the Lawrence Livermore National Laboratory (LLNL) EM Transientmore » Test Facility. We identify models of test equipment and then use these models to deconvolve the input/output sequences for the object under test. A parametric model of the object is identified from this data. The model can be used to extrapolate the response to these threat level EMP. Also discussed is the development of a facility simulator (EMSIM) useful for experimental design and calibration and a deconvolution algorithm (DECONV) useful for removing probe effects from the measured data.« less
Kang, Dukjin; Oh, Sunok; Ahn, Sung-Min; Lee, Bong-Hee; Moon, Myeong Hee
2008-08-01
Exosomes, small membrane vesicles secreted by a multitude of cell types, are involved in a wide range of physiological roles such as intercellular communication, membrane exchange between cells, and degradation as an alternative to lysosomes. Because of the small size of exosomes (30-100 nm) and the limitations of common separation procedures including ultracentrifugation and flow cytometry, size-based fractionation of exosomes has been challenging. In this study, we used flow field-flow fractionation (FlFFF) to fractionate exosomes according to differences in hydrodynamic diameter. The exosome fractions collected from FlFFF runs were examined by transmission electron microscopy (TEM) to morphologically confirm their identification as exosomes. Exosomal lysates of each fraction were digested and analyzed using nanoflow LC-ESI-MS-MS for protein identification. FIFFF, coupled with mass spectrometry, allows nanoscale size-based fractionation of exosomes and is more applicable to primary cells and stem cells since it requires much less starting material than conventional gel-based separation, in-gel digestion and the MS-MS method.
NASA Astrophysics Data System (ADS)
Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Khalek, S. Abdel; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmad, A.; Ahmadov, F.; Aielli, G.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Alimonti, G.; Alio, L.; Alison, J.; Allbrooke, B. M. M.; Allison, L. J.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Alpigiani, C.; Altheimer, A.; Gonzalez, B. Alvarez; Alviggi, M. G.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Ammosov, V. V.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arslan, O.; Artamonov, A.; Artoni, G.; Asai, S.; Asbah, N.; Ashkenazi, A.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Mayes, J. Backus; Badescu, E.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, S.; Balek, P.; Balli, F.; Banas, E.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bannoura, A. A. E.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Costa, J. Barreiro Guimarães da; Bartoldus, R.; Barton, A. E.; Bartos, P.; Bartsch, V.; Bassalat, A.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, S.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, K.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Garcia, J. A. Benitez; Benjamin, D. P.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernard, C.; Bernat, P.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Bessidskaia, O.; Besson, N.; Betancourt, C.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. 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C.; Stoebe, M.; Stoerig, K.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramania, HS.; Subramaniam, R.; Succurro, A.; Sugaya, Y.; Suhr, C.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, Y.; Svatos, M.; Swedish, S.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tamsett, M. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanasijczuk, A. J.; Tani, K.; Tannoury, N.; Tapprogge, S.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, C.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teischinger, F. A.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thoma, S.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Thong, W. M.; Thun, R. P.; Tian, F.; Tibbetts, M. J.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tiouchichine, E.; Tipton, P.; Tisserant, S.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tollefson, K.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Topilin, N. D.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Tran, H. L.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Triplett, N.; Trischuk, W.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; True, P.; Trzebinski, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turk Cakir, I.; Turra, R.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Uchida, K.; Ueda, I.; Ueno, R.; Ughetto, M.; Ugland, M.; Uhlenbrock, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Urbaniec, D.; Urquijo, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Gallego, E. Valladolid; Vallecorsa, S.; Ferrer, J. A. Valls; Van Berg, R.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; Van Der Leeuw, R.; van der Ster, D.; Eldik, N. van; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veloso, F.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Virzi, J.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; Schmitt, H. von der; Radziewski, H. von; Toerne, E. von; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, W.; Wagner, P.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Walsh, B.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, X.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Warsinsky, M.; Washbrook, A.; Wasicki, C.; Watanabe, I.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weigell, P.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wendland, D.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilkens, H. G.; Will, J. Z.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wittig, T.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wright, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xiao, M.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamada, M.; Yamaguchi, H.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, U. K.; Yang, Y.; Yanush, S.; Yao, L.; Yao, W.-M.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yen, A. L.; Yildirim, E.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zaytsev, A.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zevi della Porta, G.; Zhang, D.; Zhang, F.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, X.; Zhang, Z.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, L.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Zinonos, Z.; Ziolkowski, M.; Zitoun, R.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zutshi, V.; Zwalinski, L.
2014-07-01
Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at TeV and corresponding to an integrated luminosity of 4.7 fb. Tag-and-probe methods using events with leptonic decays of and bosons and mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.
Image use in field guides and identification keys: review and recommendations.
Leggett, Roxanne; Kirchoff, Bruce K
2011-01-01
Although illustrations have played an important role in identification keys and guides since the 18th century, their use has varied widely. Some keys lack all illustrations, while others are heavily illustrated. Even within illustrated guides, the way in which images are used varies considerably. Here, we review image use in paper and electronic guides, and establish a set of best practices for image use in illustrated keys and guides. Our review covers image use in both paper and electronic guides, though we only briefly cover apps for mobile devices. With this one exception, we cover the full range of guides, from those that consist only of species descriptions with no keys, to lavishly illustrated technical keys. Emphasis is placed on how images are used, not on the operation of the guides and key, which has been reviewed by others. We only deal with operation when it impacts image use. Few illustrated keys or guides use images in optimal ways. Most include too few images to show taxonomic variation or variation in characters and character states. The use of multiple images allows easier taxon identification and facilitates the understanding of characters. Most images are usually not standardized, making comparison between images difficult. Although some electronic guides allow images to be enlarged, many do not. The best keys and guides use standardized images, displayed at sizes that are easy to see and arranged in a standardized manner so that similar images can be compared across species. Illustrated keys and glossaries should contain multiple images for each character state so that the user can judge variation in the state. Photographic backgrounds should not distract from the subject and, where possible, should be of a standard colour. When used, drawings should be prepared by professional botanical illustrators, and clearly labelled. Electronic keys and guides should allow images to be enlarged so that their details can be seen.
Image use in field guides and identification keys: review and recommendations
Leggett, Roxanne; Kirchoff, Bruce K.
2011-01-01
Background and aims Although illustrations have played an important role in identification keys and guides since the 18th century, their use has varied widely. Some keys lack all illustrations, while others are heavily illustrated. Even within illustrated guides, the way in which images are used varies considerably. Here, we review image use in paper and electronic guides, and establish a set of best practices for image use in illustrated keys and guides. Scope Our review covers image use in both paper and electronic guides, though we only briefly cover apps for mobile devices. With this one exception, we cover the full range of guides, from those that consist only of species descriptions with no keys, to lavishly illustrated technical keys. Emphasis is placed on how images are used, not on the operation of the guides and key, which has been reviewed by others. We only deal with operation when it impacts image use. Main points Few illustrated keys or guides use images in optimal ways. Most include too few images to show taxonomic variation or variation in characters and character states. The use of multiple images allows easier taxon identification and facilitates the understanding of characters. Most images are usually not standardized, making comparison between images difficult. Although some electronic guides allow images to be enlarged, many do not. Conclusions The best keys and guides use standardized images, displayed at sizes that are easy to see and arranged in a standardized manner so that similar images can be compared across species. Illustrated keys and glossaries should contain multiple images for each character state so that the user can judge variation in the state. Photographic backgrounds should not distract from the subject and, where possible, should be of a standard colour. When used, drawings should be prepared by professional botanical illustrators, and clearly labelled. Electronic keys and guides should allow images to be enlarged so that their details can be seen. PMID:22476475
Utsunomiya, Satoshi; Ewing, Rodney C
2003-02-15
A major challenge to the development of a fundamental understanding of transport and retardation mechanisms of trace metal contaminants (<10 ppm) is their identification and characterization at the nanoscale. Atomic-scale techniques, such as conventional transmission electron microscopy, although powerful, are limited by the extremely small amounts of material that are examined. However, recent advances in electron microscopy provide a number of new analytical techniques that expand its application in environmental studies, particularly those concerning heavy metals on airborne particulates or water-borne colloids. High-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-energy-dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM) can be effectively used to identify and characterize nanoparticles. The image contrast in HAADF-STEM is strongly correlated to the atomic mass: heavier elements contribute to brighter contrast. Gold nanocrystals in pyrite and uranium nanocrystals in atmospheric aerosols have been identified by HAADF-STEM and STEM-EDX mapping and subsequently characterized by high-resolution TEM (HRTEM). EFTEM was used to identify U and Fe nanocrystals embedded in an aluminosilicate. A rare, As-bearing nanophase, westerveldite (FeAs), was identified by STEM-EDX and HRTEM. The combined use of these techniques greatly expands the effective application of electron microscopy in environmental studies, especially when applied to metals of very low concentrations. This paper describes examples of how these electron microbeam techniques can be used in combination to characterize a low concentration of heavy metals (a few ppm) on nanoscale particles.
Lepton identification at particle flow oriented detector for the future e+e- Higgs factories
NASA Astrophysics Data System (ADS)
Yu, Dan; Ruan, Manqi; Boudry, Vincent; Videau, Henri
2017-09-01
The lepton identification is essential for the physics programs at high-energy frontier, especially for the precise measurement of the Higgs boson. For this purpose, a toolkit for multivariate data analysis (TMVA) based lepton identification (LICH) has been developed for detectors using high granularity calorimeters. Using the conceptual detector geometry for the Circular Electron-Positron Collider (CEPC) and single charged particle samples with energy larger than 2 GeV, LICH identifies electrons/muons with efficiencies higher than 99.5% and controls the mis-identification rate of hadron to muons/electrons to better than 1/0.5%. Reducing the calorimeter granularity by 1-2 orders of magnitude, the lepton identification performance is stable for particles with E > 2 GeV. Applied to fully simulated eeH/μ μ H events, the lepton identification performance is consistent with the single particle case: the efficiency of identifying all the high energy leptons in an event, is 95.5-98.5%.
Prospects of Biometrics at-a-Distance
2015-09-01
PHI Protected Health Information RFID Radio-Frequency Identification SAF Small Arms Fire SEEK Secure Electronic Enrollment Kit SFPD San...data to be encoded. It also contains a Radio-Frequency Identification ( RFID ) readers and the capability to verify electronic passports and other
NASA Astrophysics Data System (ADS)
Kolb, Kimberly E.; Choi, Hee-sue S.; Kaur, Balvinder; Olson, Jeffrey T.; Hill, Clayton F.; Hutchinson, James A.
2016-05-01
The US Army's Communications Electronics Research, Development and Engineering Center (CERDEC) Night Vision and Electronic Sensors Directorate (referred to as NVESD) is developing a virtual detection, recognition, and identification (DRI) testing methodology using simulated imagery as a means of augmenting the field testing component of sensor performance evaluation, which is expensive, resource intensive, time consuming, and limited to the available target(s) and existing atmospheric visibility and environmental conditions at the time of testing. Existing simulation capabilities such as the Digital Imaging Remote Sensing Image Generator (DIRSIG) and NVESD's Integrated Performance Model Image Generator (NVIPM-IG) can be combined with existing detection algorithms to reduce cost/time, minimize testing risk, and allow virtual/simulated testing using full spectral and thermal object signatures, as well as those collected in the field. NVESD has developed an end-to-end capability to demonstrate the feasibility of this approach. Simple detection algorithms have been used on the degraded images generated by NVIPM-IG to determine the relative performance of the algorithms on both DIRSIG-simulated and collected images. Evaluating the degree to which the algorithm performance agrees between simulated versus field collected imagery is the first step in validating the simulated imagery procedure.
From organized high throughput data to phenomenological theory: The example of dielectric breakdown
NASA Astrophysics Data System (ADS)
Kim, Chiho; Pilania, Ghanshyam; Ramprasad, Rampi
Understanding the behavior (and failure) of dielectric insulators experiencing extreme electric fields is critical to the operation of present and emerging electrical and electronic devices. Despite its importance, the development of a predictive theory of dielectric breakdown has remained a challenge, owing to the complex multiscale nature of this process. Here, we focus on the intrinsic dielectric breakdown field of insulators--the theoretical limit of breakdown determined purely by the chemistry of the material, i.e., the elements the material is composed of, the atomic-level structure, and the bonding. Starting from a benchmark dataset (generated from laborious first principles computations) of the intrinsic dielectric breakdown field of a variety of model insulators, simple predictive phenomenological models of dielectric breakdown are distilled using advanced statistical or machine learning schemes, revealing key correlations and analytical relationships between the breakdown field and easily accessible material properties. The models are shown to be general, and can hence guide the screening and systematic identification of high electric field tolerant materials.
ERIC Educational Resources Information Center
Ohkawa, Chizuru
2000-01-01
Introduces teaching materials developed for field identification of plants with synoptical keys, identification tables, cards, and programs. Selects approximately 2000 seed plants and uses visibly identifiable characteristics for classification. Recommends using the methodology of identification in other areas for biological identification. (YDS)
The GlueX central drift chamber: Design and performance
DOE Office of Scientific and Technical Information (OSTI.GOV)
Van Haarlem, Y; Barbosa, F; Dey, B
2010-10-01
Tests and studies concerning the design and performance of the GlueX Central Drift Chamber (CDC) are presented. A full-scale prototype was built to test and steer the mechanical and electronic design. Small scale prototypes were constructed to test for sagging and to do timing and resolution studies of the detector. These studies were used to choose the gas mixture and to program a Monte Carlo simulation that can predict the detector response in an external magnetic field. Particle identification and charge division possibilities were also investigated.
Metabolism of clebopride in vitro. Identification of N-oxidized products.
Huizing, G; Beckett, A H
1980-01-01
1. N-(1'-Benzyl-4'-piperidyl-N-oxide)-4-amino-5-chloro-2-methoxybenzamide, N-(4'-(N-hydroxylpiperidyl)-4-amino-5-chloro-2-methoxybenzamide and N-(4'-(delta 1'-piperidyl-N-oxide))-4-amino-5-chloro-2-methoxybenzamide were obtained from chloroform extracts of incubation mixtures of clebopride or desbenzyl clebopride with 9000 g supernatant of liver homogenates of male NZW rabbits. 2. These metabolites were identified using electron impact (low and high resolution) and field desorption mass spectrometry, and computer averaged time proton magnetic resonance spectroscopy.
Magneto-optical spectra of transition metal dichalcogenides: A comparative study
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ho, Yen-Hung; Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan; Chiu, Chih-Wei
2014-12-01
Following our previous work [Ho et al., Phys. Rev. B 89, 155316 (2014)], we systematically calculate the magneto-optical properties of various transition metal dichalcogenide monolayers. The intrinsic spin-orbit coupling gives rise to the spin-split electronic states, while a perpendicular magnetic field further induces a valley splitting. In magneto-optical spectra with linearly polarized light, spectral features are spin and valley-polarized. Compounds are different from one another in terms of transition energies and appearance of twin peaks. Our numerical results can serve as a guide for future experimental identification.
9 CFR 86.4 - Official identification.
Code of Federal Regulations, 2014 CFR
2014-01-01
... the ear); (iii) Malfunction of the electronic component of a radio frequency identification (RFID) device; or (iv) Incompatibility or inoperability of the electronic component of an RFID device with the management system or unacceptable functionality of the management system due to use of an RFID device. (2...
Dalal, Anuj K; Schnipper, Jeffrey L
2016-05-01
Patient-centered communication is essential to coordinate care and safely progress patients from admission through discharge. Hospitals struggle with improving the complex and increasingly electronic conversation patterns among care team members, patients, and caregivers to achieve effective patient-centered communication across settings. Accurate and reliable identification of all care team members is a precursor to effective patient-centered communication and ideally should be facilitated by the electronic health record. However, the process of identifying care team members is challenging, and team lists in the electronic health record are typically neither accurate nor reliable. Based on the literature and on experience from 2 initiatives at our institution, we outline strategies to improve care team identification in the electronic health record and discuss potential implications for patient-centered communication. Journal of Hospital Medicine 2016;11:381-385. © 2016 Society of Hospital Medicine. © 2016 Society of Hospital Medicine.
Aad, G.; Abajyan, T.; Abbott, B.; ...
2014-07-15
Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton–proton collision data collected in 2011 at √s = 7 TeV and corresponding to an integrated luminosity of 4.7 fb -1. Tag-and-probe methods using events with leptonic decays of W and Z bosons and J/ψ mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil levelmore » for electron transverse energy greater than 30 GeV.« less
Bose, Adity; Basu, Samita
2009-03-01
Laser flash photolysis and an external magnetic field have been used for the study of the interaction of two quinone molecules, namely, 9,10-anthraquinone (AQ) and 2-methyl 1,4-naphthoquinone (or menadione, MQ) with a DNA base, cytosine (C) and its nucleoside cytidine (dC) in two media, a homogeneous one composed of acetonitrile/water (ACN/H(2)O, 9:1, v/v) and a SDS micellar heterogeneous one. We have applied an external magnetic field for the proper identification of the transients formed during the interactions in micellar media. Cytosine exhibits electron transfer (ET) followed by hydrogen abstraction (HA) while dC reveals a reduced ET compared to C, with both quinones in organic homogeneous medium (ACN/H(2)O). Due to a higher electron affinity, AQ supports more faciler ET than MQ with dC in ACN/H(2)O but observations in SDS have been just the reverse. In SDS, ET from dC is completely quenched and a dominant HA is all that could be discerned. This work reveals two main findings: first, a drop in ET on addition of a ribose unit to C, which has been attributed to a role of keto-enol tautomerism in inducing ET from electron-rich nucleus and second, the effect of medium in controlling reaction mechanism by favoring HA with AQ although it is intrinsically more prone towards ET.
Superconducting Solenoid for Superfast THz Spectroscopy
NASA Astrophysics Data System (ADS)
Bragin, A. V.; Khrushchev, S. V.; Kubarev, V. V.; Mezencev, N. A.; Tsukanov, V. M.; Sozinov, G. I.; Shkaruba, V. A.
This project is related to new spectroscopy method in little-developed THz range. The method is founded on using of a free electron laser (NovoFEL) with high spectral power radiation which can be smoothly tuned in desirable range of spectrum. The objects of research of this method are fast processes in physics, chemical and biological reactions. Uniform magnetic field of 6 T value in the research area can considerably increase possibilities of this method. The magnetic field will modulate radiation of free molecules induction on characteristic frequencies of the Zeeman splitting that gives more possibilities of identification of molecules having even weak magnetic momentum. Moreover, the use of magnetic field allows essentially increase sensitivity of this method due to almost complete separation of weak measuring signals from powerful radiation of the laser. A superconducting solenoid was developed for this method. Its design and peculiarities are described in this paper.
Thermal Skin fabrication technology
NASA Technical Reports Server (NTRS)
Milam, T. B.
1972-01-01
Advanced fabrication techniques applicable to Thermal Skin structures were investigated, including: (1) chemical machining; (2) braze bonding; (3) diffusion bonding; and (4) electron beam welding. Materials investigated were nickel and nickel alloys. Sample Thermal Skin panels were manufactured using the advanced fabrication techniques studied and were structurally tested. Results of the program included: (1) development of improved chemical machining processes for nickel and several nickel alloys; (2) identification of design geometry limits; (3) identification of diffusion bonding requirements; (4) development of a unique diffusion bonding tool; (5) identification of electron beam welding limits; and (6) identification of structural properties of Thermal Skin material.
Prototype electronic stethoscope vs. conventional stethoscope for auscultation of heart sounds.
Kelmenson, Daniel A; Heath, Janae K; Ball, Stephanie A; Kaafarani, Haytham M A; Baker, Elisabeth M; Yeh, Daniel D; Bittner, Edward A; Eikermann, Matthias; Lee, Jarone
2014-08-01
In an effort to decrease the spread of hospital-acquired infections, many hospitals currently use disposable plastic stethoscopes in patient rooms. As an alternative, this study examines a prototype electronic stethoscope that does not break the isolation barrier between clinician and patient and may also improve the diagnostic accuracy of the stethoscope exam. This study aimed to investigate whether the new prototype electronic stethoscope improved auscultation of heart sounds compared to the standard conventional isolation stethoscope. In a controlled, non-blinded, cross-over study, clinicians were randomized to identify heart sounds with both the prototype electronic stethoscope and a conventional stethoscope. The primary outcome was the score on a 10-question heart sound identification test. In total, 41 clinicians completed the study. Subjects performed significantly better in the identification of heart sounds when using the prototype electronic stethoscope (median = 9 [7-10] vs. 8 [6-9] points, p value <0.0001). Subjects also significantly preferred the prototype electronic stethoscope. Clinicians using a new prototype electronic stethoscope achieved greater accuracy in identification of heart sounds and also universally favoured the new device, compared to the conventional stethoscope.
New DMSP database of precipitating auroral electrons and ions
NASA Astrophysics Data System (ADS)
Redmon, Robert J.; Denig, William F.; Kilcommons, Liam M.; Knipp, Delores J.
2017-08-01
Since the mid-1970s, the Defense Meteorological Satellite Program (DMSP) spacecraft have operated instruments for monitoring the space environment from low Earth orbit. As the program evolved, so have the measurement capabilities such that modern DMSP spacecraft include a comprehensive suite of instruments providing estimates of precipitating electron and ion fluxes, cold/bulk plasma composition and moments, the geomagnetic field, and optical emissions in the far and extreme ultraviolet. We describe the creation of a new public database of precipitating electrons and ions from the Special Sensor J (SSJ) instrument, complete with original counts, calibrated differential fluxes adjusted for penetrating radiation, estimates of the total kinetic energy flux and characteristic energy, uncertainty estimates, and accurate ephemerides. These are provided in a common and self-describing format that covers 30+ years of DMSP spacecraft from F06 (launched in 1982) to F18 (launched in 2009). This new database is accessible at the National Centers for Environmental Information and the Coordinated Data Analysis Web. We describe how the new database is being applied to high-latitude studies of the colocation of kinetic and electromagnetic energy inputs, ionospheric conductivity variability, field-aligned currents, and auroral boundary identification. We anticipate that this new database will support a broad range of space science endeavors from single observatory studies to coordinated system science investigations.
Adhesion, friction, wear, and lubrication research by modern surface science techniques.
NASA Technical Reports Server (NTRS)
Keller, D. V., Jr.
1972-01-01
The field of surface science has undergone intense revitalization with the introduction of low-energy electron diffraction, Auger electron spectroscopy, ellipsometry, and other surface analytical techniques which have been sophisticated within the last decade. These developments have permitted submono- and monolayer structure analysis as well as chemical identification and quantitative analysis. The application of a number of these techniques to the solution of problems in the fields of friction, lubrication, and wear are examined in detail for the particular case of iron; and in general to illustrate how the accumulation of pure data will contribute toward the establishment of physiochemical concepts which are required to understand the mechanisms that are operational in friction systems. In the case of iron, LEED, Auger and microcontact studies have established that hydrogen and light-saturated organic vapors do not establish interfaces which prevent iron from welding, whereas oxygen and some oxygen and sulfur compounds do reduce welding as well as the coefficient of friction. Interpretation of these data suggests a mechanism of sulfur interaction in lubricating systems.
Diagnostics for real-time plasma control in PBX-M
NASA Astrophysics Data System (ADS)
Kaita, R.; Batha, S.; Bell, R. E.; Bernabei, S.; Hatcher, R.; Kozub, T.; Kugel, H.; Levinton, F.; Okabayashi, M.; Sesnic, S.; von Goeler, S.; Zolfaghari, A.; PBX-M Group
1995-01-01
An important issue for future tokamaks is real-time plasma control for the avoidance of magnetohydrodynamic instabilities and other applications that require detailed plasma profile and fluctuation data. Although measurements from diagnostics providing this information require significantly more processing than magnetic flux data, recent advancements could make them practical for adjusting operational settings for plasma heating and current drive systems as well as field coil currents. On the Princeton Beta Experiment-Modification (PBX-M), the lower hybrid current drive phasing can be varied during a plasma shot using digitally programmable ferrite phase shifters, and neural beam functions can be fully computer controlled. PBX-M diagnostics that may be used for control purposes include motional Stark-effect polarimetry for magnetic field pitch angle profiles, soft x-ray arrays for plasma position control and the separation of βp from li, hard x-ray detectors for energetic electron distributions, a multichannel electron cyclotron emission radiometer for ballooning mode identification, and passive plate eddy current monitors for kink stabilization. We will describe the present status of these systems on PBX-M, and discuss their suitability for feedback applications.
Fungicide residue identification and discrimination using a conducting polymer electronic-nose
Alphus D. Wilson
2013-01-01
The identification of fungicide residues on crop foliage is necessary to make periodic pest management decisions. The determination of fungicide residue identities currently is difficult and time consuming using conventional chemical analysis methods such as gas chromatography-mass spectroscopy. Different fungicide types produce unique electronic aroma signature...
TEM-EELS Investigation of Boron and Phosphorus Passivated 4H-SiC/SiO2 Interface Structures
NASA Astrophysics Data System (ADS)
Klingshirn, Christopher; Taillon, Joshua; Liu, Gang; Dhar, Sarit; Feldman, Leonard; Zheleva, Tsvetanka; Lelis, Aivars; Salamanca-Riba, Lourdes
A high density of electronic defects at the SiC/SiO2 interface adversely affects SiC-based metal oxide semiconductor devices. Various treatments are known to improve device performance. Annealing in a nitric oxide (NO) environment, for example, passivates electronic defects at the interface and raises the carrier mobility in the active region to 35-40 cm2/Vs, but the effect saturates after about 60 minutes of annealing. Passivation with phosphorus or boron improves upon NO by a factor of 2, increasing the mobility to over 90 cm2/Vs.2 We investigate the chemical and structural effects of these treatments on the SiC/SiO2 transition layer using high-resolution transmission electron microscopy (HRTEM) and high angle annular dark field (HAADF). Electron energy loss spectroscopy Spectrum Imaging (EELS SI) collected across the transition region allow identification of the width, composition and types of bonding at the transition layer. Advanced machine learning techniques applied to the EELS data reveal intermediate bonding states within this region. Supported by ARL under Grant No. W911NF1420110.
Anatomy of Biometric Passports
Malčík, Dominik; Drahanský, Martin
2012-01-01
Travelling is becoming available for more and more people. Millions of people are on a way every day. That is why a better control over global human transfer and a more reliable identity check is desired. A recent trend in a field of personal identification documents is to use RFID (Radio Frequency Identification) technology and biometrics, especially (but not only) in passports. This paper provides an insight into the electronic passports (also called e-passport or ePassport) implementation chosen in the Czech Republic. Such a summary is needed for further studies of biometric passports implementation security and biometric passports analysis. A separate description of the Czech solution is a prerequisite for a planned analysis, because of the uniqueness of each implementation. (Each country can choose the implementation details within a range specified by the ICAO (International Civil Aviation Organisation); moreover, specific security mechanisms are optional and can be omitted). PMID:22969272
Identification of a localized core mode in a helicon plasma
NASA Astrophysics Data System (ADS)
Green, Daniel A.; Chakraborty Thakur, Saikat; Tynan, George R.; Light, Adam D.
2017-10-01
We present imaging measurements of a newly observed mode in the core of the Controlled Shear Decorrelation Experiment - Upgrade (CSDX-U). CSDX-U is a well-characterized linear machine producing dense plasmas relevant to the tokamak edge (Te 3 eV, ne 1013 /cc). Typical fluctuations are dominated by electron drift waves, with evidence for Kelvin-Helmholtz vortices appearing near the plasma edge. A new mode has been observed using high-speed imaging that appears at high magnetic field strengths and is confined to the inner third of the plasma column. A cross-spectral phase technique allows direct visualization of dominant spatial structures as a function of frequency. Experimental dispersion curve estimates are constructed from imaging data alone, and allow direct comparison of theoretical dispersion relations to the observed mode. We present preliminary identification of the mode based on its dispersion curve, and compare the results with electrostatic probe measurements.
Anatomy of biometric passports.
Malčík, Dominik; Drahanský, Martin
2012-01-01
Travelling is becoming available for more and more people. Millions of people are on a way every day. That is why a better control over global human transfer and a more reliable identity check is desired. A recent trend in a field of personal identification documents is to use RFID (Radio Frequency Identification) technology and biometrics, especially (but not only) in passports. This paper provides an insight into the electronic passports (also called e-passport or ePassport) implementation chosen in the Czech Republic. Such a summary is needed for further studies of biometric passports implementation security and biometric passports analysis. A separate description of the Czech solution is a prerequisite for a planned analysis, because of the uniqueness of each implementation. (Each country can choose the implementation details within a range specified by the ICAO (International Civil Aviation Organisation); moreover, specific security mechanisms are optional and can be omitted).
Farrow, Darcie A; Smith, Eric R; Qian, Wei; Jonas, David M
2008-11-07
By analogy to the Raman depolarization ratio, vibrational quantum beats in pump-probe experiments depend on the relative pump and probe laser beam polarizations in a way that reflects vibrational symmetry. The polarization signatures differ from those in spontaneous Raman scattering because the order of field-matter interactions is different. Since pump-probe experiments are sensitive to vibrations on excited electronic states, the polarization anisotropy of vibrational quantum beats can also reflect electronic relaxation processes. Diagrammatic treatments, which expand use of the symmetry of the two-photon tensor to treat signal pathways with vibrational and vibronic coherences, are applied to find the polarization anisotropy of vibrational and vibronic quantum beats in pump-probe experiments for different stages of electronic relaxation in square symmetric molecules. Asymmetric vibrational quantum beats can be distinguished from asymmetric vibronic quantum beats by a pi phase jump near the center of the electronic spectrum and their disappearance in the impulsive limit. Beyond identification of vibrational symmetry, the vibrational quantum beat anisotropy can be used to determine if components of a doubly degenerate electronic state are unrelaxed, dephased, population exchanged, or completely equilibrated.
First-order metal-insulator transitions in vanadates from first principles
NASA Astrophysics Data System (ADS)
Kumar, Anil; Rabe, Karin
2013-03-01
Materials that exhibit first-order metal-insulator transitions, with the accompanying abrupt change in the conductivity, have potential applications as switches in future electronic devices. Identification of materials and exploration of the atomic-scale mechanisms for switching between the two electronic states is a focus of current research. In this work, we search for first-order metal-insulator transitions in transition metal compounds, with a particular focus on d1 and d2 systems, by using first principles calculations to screen for an alternative low-energy state having not only a electronic character opposite to that of the ground state, but a distinct structure and/or magnetic ordering which would permit switching by an applied field or stress. We will present the results of our investigation of the perovskite compounds SrVO3, LaVO3, CaVO3, YVO3, LaTiO3 and related layered phase, including superlattices and Ruddlesden-Popper phases. While the pure compounds do not satisfy the search criteria, the layered phases show promising results.
Insights into the physical chemistry of materials from advances in HAADF-STEM
Sohlberg, Karl; Pennycook, Timothy J.; Zhou, Wu; ...
2014-11-13
The observation that, ‘‘New tools lead to new science’’[P. S. Weiss, ACS Nano., 2012, 6(3), 1877–1879], is perhaps nowhere more evident than in scanning transmission electron microscopy (STEM). Advances in STEM have endowed this technique with several powerful and complimentary capabilities. For example, the application of high-angle annular dark-field imaging has made possible real-space imaging at subangstrom resolution with Z-contrast (Z = atomic number). Further advances have wrought: simultaneous real-space imaging and elemental identification by using electron energy loss spectroscopy (EELS); 3-dimensional (3D) mapping by depth sectioning; monitoring of surface diffusion by time-sequencing of images; reduced electron energy imaging formore » probing graphenes; etc. In this paper we review how these advances, often coupled with first-principles theory, have led to interesting and important new insights into the physical chemistry of materials. We then review in detail a few specific applications that highlight some of these STEM capabilities.« less
The Mu2e undoped CsI crystal calorimeter
NASA Astrophysics Data System (ADS)
Atanov, N.; Baranov, V.; Budagov, J.; Cervelli, F.; Colao, F.; Cordelli, M.; Corradi, G.; Davydov, Y. I.; Di Falco, S.; Diociaiuti, E.; Donati, S.; Donghia, R.; Echenard, B.; Giovannella, S.; Glagolev, V.; Grancagnolo, F.; Happacher, F.; Hitlin, D. G.; Martini, M.; Miscetti, S.; Miyashita, T.; Morescalchi, L.; Murat, P.; Pedreschi, E.; Pezzullo, G.; Porter, F.; Raffaelli, F.; Ricci, M.; Saputi, A.; Sarra, I.; Spinella, F.; Tassielli, G.; Tereshchenko, V.; Usubov, Z.; Zhu, R. Y.
2018-02-01
The Mu2e experiment at Fermilab will search for Charged Lepton Flavor Violating conversion of a muon to an electron in an atomic field. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter and an external system, surrounding the solenoid, to veto cosmic rays. The calorimeter plays an important role to provide: a) excellent particle identification capabilities; b) a fast trigger filter; c) an easier tracker track reconstruction. Two disks, located downstream of the tracker, contain 674 pure CsI crystals each. Each crystal is read out by two arrays of UV-extended SiPMs. The choice of the crystals and SiPMs has been finalized after a thorough test campaign. A first small scale prototype consisting of 51 crystals and 102 SiPM arrays has been exposed to an electron beam at the BTF (Beam Test Facility) in Frascati. Although the readout electronics were not final, results show that the current design is able to meet the timing and energy resolution required by the Mu2e experiment.
Layer Number and Stacking Order Imaging of Few-layer Graphenes by Transmission Electron Microscopy
NASA Astrophysics Data System (ADS)
Ping, Jinglei; Fuhrer, Michael
2012-02-01
A method using transmission electron microscopy (TEM) selected area electron diffraction (SAED) patterns and dark field (DF) images is developed to identify graphene layer number and stacking order by comparing intensity ratios of SAED spots with theory. Graphene samples are synthesized by ambient pressure chemical vapor depostion and then etched by hydrogen in high temperature to produce samples with crystalline stacking but varying layer number on the nanometer scale. Combined DF images from first- and second-order diffraction spots are used to produce images with layer-number and stacking-order contrast with few-nanometer resolution. This method is proved to be accurate enough for quantative stacking-order-identification of graphenes up to at least four layers. This work was partially supported by Science of Precision Multifunctional Nanostructures for Elecrical Energy Storage, an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160.
Wall, Kristin M; Kilembe, William; Inambao, Mubiana; Chen, Yi No; Mchoongo, Mwaka; Kimaru, Linda; Hammond, Yuna Tiffany; Sharkey, Tyronza; Malama, Kalonde; Fulton, T Roice; Tran, Alex; Halumamba, Hanzunga; Anderson, Sarah; Kishore, Nishant; Sarwar, Shawn; Finnegan, Trisha; Mark, David; Allen, Susan A
2015-06-27
Patient identification within and between health services is an operational challenge in many resource-limited settings. When following HIV risk groups for service provision and in the context of vaccine trials, patient misidentification can harm patient care and bias trial outcomes. Electronic fingerprinting has been proposed to identify patients over time and link patient data between health services. The objective of this study was to determine 1) the feasibility of implementing an electronic-fingerprint linked data capture system in Zambia and 2) the acceptability of this system among a key HIV risk group: female sex workers (FSWs). Working with Biometrac, a US-based company providing biometric-linked healthcare platforms, an electronic fingerprint-linked data capture system was developed for use by field recruiters among Zambian FSWs. We evaluated the technical feasibility of the system for use in the field in Zambia and conducted a pilot study to determine the acceptability of the system, as well as barriers to uptake, among FSWs. We found that implementation of an electronic fingerprint-linked patient tracking and data collection system was feasible in this relatively resource-limited setting (false fingerprint matching rate of 1/1000 and false rejection rate of <1/10,000) and was acceptable among FSWs in a clinic setting (2% refusals). However, our data indicate that less than half of FSWs are comfortable providing an electronic fingerprint when recruited while they are working. The most common reasons cited for not providing a fingerprint (lack of privacy/confidentiality issues while at work, typically at bars or lodges) could be addressed by recruiting women during less busy hours, in their own homes, in the presence of "Queen Mothers" (FSW organizers), or in the presence of a FSW that has already been fingerprinted. Our findings have major implications for key population research and improved health services provision. However, more work needs to be done to increase the acceptability of the electronic fingerprint-linked data capture system during field recruitment. This study indicated several potential avenues that will be explored to increase acceptability.
42 CFR 37.60 - Submitting required chest roentgenograms and miner identification documents.
Code of Federal Regulations, 2012 CFR
2012-10-01
... prescribed in this subpart, all the forms shall be submitted with his or her name and social security account... miner identification document containing the miner's name, address, social security number and place of... format specified by NIOSH either using portable electronic media, or a secure electronic file transfer...
GuiaTreeKey, a multi-access electronic key to identify tree genera in French Guiana.
Engel, Julien; Brousseau, Louise; Baraloto, Christopher
2016-01-01
The tropical rainforest of Amazonia is one of the most species-rich ecosystems on earth, with an estimated 16000 tree species. Due to this high diversity, botanical identification of trees in the Amazon is difficult, even to genus, often requiring the assistance of parataxonomists or taxonomic specialists. Advances in informatics tools offer a promising opportunity to develop user-friendly electronic keys to improve Amazonian tree identification. Here, we introduce an original multi-access electronic key for the identification of 389 tree genera occurring in French Guiana terra-firme forests, based on a set of 79 morphological characters related to vegetative, floral and fruit characters. Its purpose is to help Amazonian tree identification and to support the dissemination of botanical knowledge to non-specialists, including forest workers, students and researchers from other scientific disciplines. The electronic key is accessible with the free access software Xper ², and the database is publicly available on figshare: https://figshare.com/s/75d890b7d707e0ffc9bf (doi: 10.6084/m9.figshare.2682550).
Design, status and test of the Mu2e crystal calorimeter
NASA Astrophysics Data System (ADS)
Atanov, N.; Baranov, V.; Budagov, J.; Carosi, R.; Cervelli, F.; Colao, F.; Cordelli, M.; Corradi, G.; Dané, E.; Davydov, Y. I.; Di Falco, S.; Donati, S.; Donghia, R.; Echenard, B.; Flood, K.; Giovannella, S.; Glagolev, V.; Grancagnolo, F.; Happacher, F.; Hitlin, D. G.; Martini, M.; Miscetti, S.; Miyashita, T.; Morescalchi, L.; Murat, P.; Piacentino, G. M.; Pezzullo, G.; Raffaelli, F.; Saputi, A.; Sarra, I.; Spinella, F.; Tassielli, G.; Tereshchenko, V.; Usubov, Z.; Zhu, R. Y.
2017-11-01
The Mu2e experiment at Fermilab searches for the charged-lepton flavor violating neutrino-less conversion of a negative muon into an electron in the field of an aluminum nucleus. The dynamics of such a process is well modeled by a two-body decay, resulting in a monoenergetic electron with an energy slightly below the muon rest mass (104.967 MeV). The calorimeter of this experiment plays an important role to provide excellent particle identification capabilities and an online trigger filter while aiding the track reconstruction capabilities. The baseline calorimeter configuration consists of two disks each made with ˜ 700 undoped CsI crystals read out by two large area UV-extended Silicon Photomultipliers. These crystals match the requirements for stability of response, high resolution and radiation hardness. In this paper we present the final calorimeter design.
Yu, Zhenhong; Herndon, Scott C; Ziemba, Luke D; Timko, Michael T; Liscinsky, David S; Anderson, Bruce E; Miake-Lye, Richard C
2012-09-04
Lubrication oil was identified in the organic particulate matter (PM) emissions of engine exhaust plumes from in-service commercial aircraft at Chicago Midway Airport (MDW) and O'Hare International Airport (ORD). This is the first field study focused on aircraft lubrication oil emissions, and all of the observed plumes described in this work were due to near-idle engine operations. The identification was carried out with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF AMS) via a collaborative laboratory and field investigation. A characteristic mass marker of lubrication oil, I(85)/I(71), the ratio of ion fragment intensity between m/z = 85 and 71, was used to distinguish lubrication oil from jet engine combustion products. This AMS marker was based on ion fragmentation patterns measured using electron impact ionization for two brands of widely used lubrication oil in a laboratory study. The AMS measurements of exhaust plumes from commercial aircraft in this airport field study reveal that lubrication oil is commonly present in organic PM emissions that are associated with emitted soot particles, unlike the purely oil droplets observed at the lubrication system vent. The characteristic oil marker, I(85)/I(71), was applied to quantitatively determine the contribution from lubrication oil in measured aircraft plumes, which ranges from 5% to 100%.
Particle identification for a future EIC detector
NASA Astrophysics Data System (ADS)
Ilieva, Y.; Allison, L.; Barber, C.; Cao, T.; Del Dotto, A.; Gleason, C.; He, X.; Kalicy, G.; McKisson, J.; Nadel-Turonski, P.; Park, K.; Rapoport, J.; Schwarz, C.; Schwiening, J.; Wong, C. P.; Zhao, Zh.; Zorn, C.
2018-03-01
In its latest Long Range Plan for Nuclear Science Research in the U.S., the Nuclear Science Advisory Committee to the Department of Energy recommended that in regards to new nuclear-physics facilities, the construction of an Electron Ion Collider (EIC) be of the highest priority after the completion of the Facility for Rare Isotope Beams. In order to carry out key aspects of the scientific program of the EIC, the EIC central detector must be capable of hadron particle identification (PID) over a broad momentum range of up to 50 GeV/c. The goal of the EIC-PID consortium is to develop an integrated program for PID at EIC, which employs several different technologies for imaging Cherenkov detectors. Here we discuss the conceptual designs and the expected PID performance of two of these detectors, as well as the newest results of gain evaluation studies of photon sensors that are good candidates to read out these detectors. Development of a gas-aerogel dual-radiator Ring Imaging Cherenkov (dRICH) detector with outward focusing mirrors is being pursued for the hadron endcap. Simulations demonstrate that the dRICH can provide a continuous >= 3σ π /K/p separation from 2.5 GeV/c to 50 GeV/c. A modular aerogel Ring Imaging Cherenkov (mRICH) detector with a Fresnel lens as a focusing element is being pursued for the electron endcap. The design provides for hadron identification over a momentum range of 3 GeV/c-10 GeV/c. The working principle of the mRICH design has been proven in a beam test with a first prototype. The location of the sensor readout planes of the Cherenkov detectors in the magnetic field of the central-detector solenoid, which is expected to be within 1.5 T-3 T, makes is necessary to evaluate the limit of the acceptable performance of commercially available photosensors, such as microchannel-plate photomultipliers (MCP PMTs). Here we present the results of gain evaluation of multi-anode MCP PMTs with a pore size of 10 μm. Overall, our preliminary results suggest that the 10-μm pore-size sensors can be operated in a magnetic field with magnitude up to Bmax of 2 T. The value of Bmax depends on the relative orientation between the sensor and the field.
Periasamy, Vengadesh; Rizan, Nastaran; Al-Ta’ii, Hassan Maktuff Jaber; Tan, Yee Shin; Tajuddin, Hairul Annuar; Iwamoto, Mitsumasa
2016-01-01
The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unreliable and is not sufficiently useful for the identification of fungi genera. Many of these methods have failed when it comes to identification of closely related species of certain genus like Pleurotus. Our electronics profiles, both in the negative and positive bias regions were however found to be highly characteristic according to the base-pair sequences. We believe that this simple, low-cost and practical method could be useful towards identifying and detecting DNA in biotechnology and pathology. PMID:27435636
NASA Astrophysics Data System (ADS)
Periasamy, Vengadesh; Rizan, Nastaran; Al-Ta'Ii, Hassan Maktuff Jaber; Tan, Yee Shin; Tajuddin, Hairul Annuar; Iwamoto, Mitsumasa
2016-07-01
The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unreliable and is not sufficiently useful for the identification of fungi genera. Many of these methods have failed when it comes to identification of closely related species of certain genus like Pleurotus. Our electronics profiles, both in the negative and positive bias regions were however found to be highly characteristic according to the base-pair sequences. We believe that this simple, low-cost and practical method could be useful towards identifying and detecting DNA in biotechnology and pathology.
An Overview of Some Electronic Identification Use Cases in Europe
NASA Astrophysics Data System (ADS)
Mattatia, Fabrice
As online services become more and more widely used, and as the exchanges of personal data become more and more widespread, electronic identification appears to be a key function for the security of the process and for the protection of privacy. It is the sole means of ensuring only authorized people have access to the data. In France and throughout Europe, e-government services, as well as private services, already use different means of electronic identification. Among the different technical solutions stand the electronic identity card: around 20 million eID cards have already been issued in Europe. The question of their interoperability is now open, in order that all European citizens may access the e-services of any Member State. With the development of electronic administration comes the need for the citizen to be able to prove his or her identity. This is essential if the citizen wants access to her personal data or administrative files, or if he wants to claim a right attached to his very identity. On the other hand, administrations have the obligation to ensure the personal data they store are not displayed to people who are not entitled to see them. They also have the need to detect fraudsters. Electronic identification, which is the ability to prove someone's identity on the Internet, thus becomes a central matter.
Transforming Mobile Platform with KI-SIM Card into an Open Mobile Identity Tool
NASA Astrophysics Data System (ADS)
Hyppönen, Konstantin; Hassinen, Marko; Trichina, Elena
Recent introduction of Near Field Communication (NFC) in mobile phones has stimulated the development of new proximity payment and identification services. We present an architecture that facilitates the use of the mobile phone as a personalised electronic identity tool. The tool can work as a replacement for numerous ID cards and licenses. Design for privacy principles have been applied, such as minimisation of data collection and informed consent of the user. We describe an implementation of a lightweight version of the of the mobile identity tool using currently available handset technology and off-the-shelf development tools.
Rotational frequencies of transition metal hydrides for astrophysical searches in the far-infrared
NASA Technical Reports Server (NTRS)
Brown, John M.; Beaton, Stuart P.; Evenson, Kenneth M.
1993-01-01
Accurate frequencies for the lowest rotational transitions of five transition metal hydrides (CrH, FeH, CoH, NiH, and CuH) in their ground electronic states are reported to help the identification of these species in astrophysical sources from their far-infrared spectra. Accurate frequencies are determined in two ways: for CuH, by calculation from rotational constants determined from higher J transitions with an accuracy of 190 kHz; for the other species, by extrapolation to zero magnetic field from laser magnetic resonance spectra with an accuracy of 0.7 MHz.
ERIC Educational Resources Information Center
Stagg, Bethan C.; Donkin, Maria E.
2017-01-01
We investigated usability of mobile computers and field guide books with adult botanical novices, for the identification of wildflowers and deciduous trees in winter. Identification accuracy was significantly higher for wildflowers using a mobile computer app than field guide books but significantly lower for deciduous trees. User preference…
Braem, G; De Vliegher, S; Supré, K; Haesebrouck, F; Leroy, F; De Vuyst, L
2011-01-10
Due to significant financial losses in the dairy cattle farming industry caused by mastitis and the possible influence of coagulase-negative staphylococci (CNS) in the development of this disease, accurate identification methods are needed that untangle the different species of the diverse CNS group. In this study, 39 Staphylococcus type strains and 253 field isolates were subjected to (GTG)(5)-PCR fingerprinting to construct a reference framework for the classification and identification of different CNS from (sub)clinical milk samples and teat apices swabs. Validation of the reference framework was performed by dividing the field isolates in two separate groups and testing whether one group of field isolates, in combination with type strains, could be used for a correct classification and identification of a second group of field isolates. (GTG)(5)-PCR fingerprinting achieved a typeability of 94.7% and an accuracy of 94.3% compared to identifications based on gene sequencing. The study shows the usefulness of the method to determine the identity of bovine Staphylococcus species, provided an identification framework updated with field isolates is available. Copyright © 2010 Elsevier B.V. All rights reserved.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kim, Chiho; Pilania, Ghanshyam; Ramprasad, Ramamurthy
Understanding the behavior (and failure) of dielectric insulators experiencing extreme electric fields is critical to the operation of present and emerging electrical and electronic devices. Despite its importance, the development of a predictive theory of dielectric breakdown has remained a challenge, owing to the complex multiscale nature of this process. We focus on the intrinsic dielectric breakdown field of insulators—the theoretical limit of breakdown determined purely by the chemistry of the material, i.e., the elements the material is composed of, the atomic-level structure, and the bonding. Starting from a benchmark dataset (generated from laborious first principles computations) of the intrinsicmore » dielectric breakdown field of a variety of model insulators, simple predictive phenomenological models of dielectric breakdown are distilled using advanced statistical or machine learning schemes, revealing key correlations and analytical relationships between the breakdown field and easily accessible material properties. Lastly, the models are shown to be general, and can hence guide the screening and systematic identification of high electric field tolerant materials.« less
Kim, Chiho; Pilania, Ghanshyam; Ramprasad, Ramamurthy
2016-02-02
Understanding the behavior (and failure) of dielectric insulators experiencing extreme electric fields is critical to the operation of present and emerging electrical and electronic devices. Despite its importance, the development of a predictive theory of dielectric breakdown has remained a challenge, owing to the complex multiscale nature of this process. We focus on the intrinsic dielectric breakdown field of insulators—the theoretical limit of breakdown determined purely by the chemistry of the material, i.e., the elements the material is composed of, the atomic-level structure, and the bonding. Starting from a benchmark dataset (generated from laborious first principles computations) of the intrinsicmore » dielectric breakdown field of a variety of model insulators, simple predictive phenomenological models of dielectric breakdown are distilled using advanced statistical or machine learning schemes, revealing key correlations and analytical relationships between the breakdown field and easily accessible material properties. Lastly, the models are shown to be general, and can hence guide the screening and systematic identification of high electric field tolerant materials.« less
Prognostics of Power Electronics, Methods and Validation Experiments
NASA Technical Reports Server (NTRS)
Kulkarni, Chetan S.; Celaya, Jose R.; Biswas, Gautam; Goebel, Kai
2012-01-01
Abstract Failure of electronic devices is a concern for future electric aircrafts that will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. As a result, investigation of precursors to failure in electronics and prediction of remaining life of electronic components is of key importance. DC-DC power converters are power electronics systems employed typically as sourcing elements for avionics equipment. Current research efforts in prognostics for these power systems focuses on the identification of failure mechanisms and the development of accelerated aging methodologies and systems to accelerate the aging process of test devices, while continuously measuring key electrical and thermal parameters. Preliminary model-based prognostics algorithms have been developed making use of empirical degradation models and physics-inspired degradation model with focus on key components like electrolytic capacitors and power MOSFETs (metal-oxide-semiconductor-field-effect-transistor). This paper presents current results on the development of validation methods for prognostics algorithms of power electrolytic capacitors. Particularly, in the use of accelerated aging systems for algorithm validation. Validation of prognostics algorithms present difficulties in practice due to the lack of run-to-failure experiments in deployed systems. By using accelerated experiments, we circumvent this problem in order to define initial validation activities.
Noise Source Identification in a Reverberant Field Using Spherical Beamforming
NASA Astrophysics Data System (ADS)
Choi, Young-Chul; Park, Jin-Ho; Yoon, Doo-Byung; Kwon, Hyu-Sang
Identification of noise sources, their locations and strengths, has been taken great attention. The method that can identify noise sources normally assumes that noise sources are located at a free field. However, the sound in a reverberant field consists of that coming directly from the source plus sound reflected or scattered by the walls or objects in the field. In contrast to the exterior sound field, reflections are added to sound field. Therefore, the source location estimated by the conventional methods may give unacceptable error. In this paper, we explain the effects of reverberant field on interior source identification process and propose the method that can identify noise sources in the reverberant field.
Electron Energy Loss Spectroscopy imaging of surface plasmons at the nanometer scale.
Colliex, Christian; Kociak, Mathieu; Stéphan, Odile
2016-03-01
Since their first realization, electron microscopes have demonstrated their unique ability to map with highest spatial resolution (sub-atomic in most recent instruments) the position of atoms as a consequence of the strong scattering of the incident high energy electrons by the nuclei of the material under investigation. When interacting with the electron clouds either on atomic orbitals or delocalized over the specimen, the associated energy transfer, measured and analyzed as an energy loss (Electron Energy Loss Spectroscopy) gives access to analytical properties (atom identification, electron states symmetry and localization). In the moderate energy-loss domain (corresponding to an optical spectral domain from the infrared (IR) to the rather far ultra violet (UV), EELS spectra exhibit characteristic collective excitations of the rather-free electron gas, known as plasmons. Boundary conditions, such as surfaces and/or interfaces between metallic and dielectric media, generate localized surface charge oscillations, surface plasmons (SP), which are associated with confined electric fields. This domain of research has been extraordinarily revived over the past few years as a consequence of the burst of interest for structures and devices guiding, enhancing and controlling light at the sub-wavelength scale. The present review focuses on the study of these surface plasmons with an electron microscopy-based approach which associates spectroscopy and mapping at the level of a single and well-defined nano-object, typically at the nanometer scale i.e. much improved with respect to standard, and even near-field, optical techniques. After calling to mind some early studies, we will briefly mention a few basic aspects of the required instrumentation and associated theoretical tools to interpret the very rich data sets recorded with the latest generation of (Scanning)TEM microscopes. The following paragraphs will review in more detail the results obtained on simple planar and spherical surfaces (or interfaces), extending then to more complex geometries isolated and in interaction, thus establishing basic rules from the classical to the quantum domain. A few hints towards application domains and prospective fields rich of interest will finally be indicated, confirming the demonstrated key role of electron-beam nanoplasmonics, the more as an yet-enhanced energy resolution down to the 10meV comes on the verge of current access. Copyright © 2015 Elsevier B.V. All rights reserved.
Use of dc Ar microdischarge with nonlocal plasma for identification of metal samples
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kudryavtsev, A. A., E-mail: akud@ak2138.spb.edu; Stefanova, M. S.; Pramatarov, P. M.
2015-04-07
The possibility of using the collisional electron spectroscopy (CES) method for the detection of atoms from metal samples is experimentally verified. The detection and identification of metal atoms from a Pt sample in the nonlocal plasma of short (without positive column) dc Ar microdischarge at intermediate pressures (5–30 Torr) is realized in this work. Cathode sputtering is used for atomization of the metal under analysis. The identification of the analyzed metal is made from the energy spectra of groups of fast nonlocal electrons—characteristic electrons released in the Penning ionization of the Pt atoms by Ar metastable atoms and molecules. The acquisitionmore » of the electron energy spectra is performed using an additional electrode—a sensor located at the boundary of the discharge volume. The Pt characteristic Penning electrons form the maxima in the electron energy spectra at the energies of their appearance, which are 2.6 eV and 1.4 eV. From the measured energy of the maxima, identification of the metal atoms is accomplished. The characteristic Ar maxima due to pair collisions between Ar metastable atoms and molecules and super-elastic collisions are also recorded. This study demonstrates the possibility of creating a novel microplasma analyzer for atoms from metal samples.« less
Toward the development of portable miniature intelligent electronic color identification devices
NASA Astrophysics Data System (ADS)
Nicolau, Dan V., Jr.; Livingston, Peter; Jahshan, David; Evans, Rob
2004-03-01
The identification and differentiation of colours is a relatively problematic task for colour-impaired and partially vision-impaired persons and an impossible one for completely blind. In various contexts, this leads to a loss of independence or an increased risk of harm. The identification of colour using optoelectronic devices, on the other hand, can be done precisely and inexpensively. Additionally, breakthroughs in miniaturising and integrating colour sensors into biological systems may lead to significant advances in electronic implants for alleviating blindness. Here we present a functional handheld device developed for the identification of colour, intended for use by the vision-impaired. We discuss the features and limitations of the device and describe in detail one target application - the identification of different banknote denominations by the blind.
Identification and discrimination of herbicide residues using a conducting polymer electronic nose
Alphus Dan Wilson
2016-01-01
The identification of herbicide residues on crop foliage is necessary to make crop-management decisions for weed pest control and to monitor pesticide residue levels on food crops. Electronic-nose (e-nose) methods were tested as a cheaper, alternative means of discriminating between herbicide residue types (compared with conventional chromatography methods), by...
A. Dan Wilson; D.G. Lester; C.S. Oberle
2004-01-01
Conductive polymer analysis, a type of electronic aroma detection technology, was evaluated for its efficacy in the detection, identification, and discrimination of plant-pathogenic microorganisms on standardized media and in diseased plant tissues. The method is based on the acquisition of a diagnostic electronic fingerprint derived from multisensor responses to...
NASA Astrophysics Data System (ADS)
Giraudeau, A.; Pierron, F.
2010-06-01
The paper presents an experimental application of a method leading to the identification of the elastic and damping material properties of isotropic vibrating plates. The theory assumes that the searched parameters can be extracted from curvature and deflection fields measured on the whole surface of the plate at two particular instants of the vibrating motion. The experimental application consists in an original excitation fixture, a particular adaptation of an optical full-field measurement technique, a data preprocessing giving the curvature and deflection fields and finally in the identification process using the Virtual Fields Method (VFM). The principle of the deflectometry technique used for the measurements is presented. First results of identification on an acrylic plate are presented and compared to reference values. Details about a new experimental arrangement, currently in progress, is presented. It uses a high speed digital camera to over sample the full-field measurements.
Unconventional superconductivity in Y5Rh6Sn18 probed by muon spin relaxation
Bhattacharyya, Amitava; Adroja, Devashibhai; Kase, Naoki; Hillier, Adrian; Akimitsu, Jun; Strydom, Andre
2015-01-01
Conventional superconductors are robust diamagnets that expel magnetic fields through the Meissner effect. It would therefore be unexpected if a superconducting ground state would support spontaneous magnetics fields. Such broken time-reversal symmetry states have been suggested for the high—temperature superconductors, but their identification remains experimentally controversial. We present magnetization, heat capacity, zero field and transverse field muon spin relaxation experiments on the recently discovered caged type superconductor Y5Rh6Sn18 ( TC= 3.0 K). The electronic heat capacity of Y5Rh6Sn18 shows a T3 dependence below Tc indicating an anisotropic superconducting gap with a point node. This result is in sharp contrast to that observed in the isostructural Lu5Rh6Sn18 which is a strong coupling s—wave superconductor. The temperature dependence of the deduced superfluid in density Y5Rh6Sn18 is consistent with a BCS s—wave gap function, while the zero-field muon spin relaxation measurements strongly evidences unconventional superconductivity through a spontaneous appearance of an internal magnetic field below the superconducting transition temperature, signifying that the superconducting state is categorized by the broken time-reversal symmetry. PMID:26286229
A Field Study of an Iris Identification System
2008-05-01
conducted a field trial of a commercial iris identification scanner at the US Navy Fleet Numerical Meterology and Oceanography Center (FNMOC) in...identification scanner at the US Navy Fleet Numerical Meterology and Oceanography Center (FNMOC) in Mon- terey, CA. Scans were performed by US military guards
2D layered transport properties from topological insulator Bi2Se3 single crystals and micro flakes
Chiatti, Olivio; Riha, Christian; Lawrenz, Dominic; Busch, Marco; Dusari, Srujana; Sánchez-Barriga, Jaime; Mogilatenko, Anna; Yashina, Lada V.; Valencia, Sergio; Ünal, Akin A.; Rader, Oliver; Fischer, Saskia F.
2016-01-01
Low-field magnetotransport measurements of topological insulators such as Bi2Se3 are important for revealing the nature of topological surface states by quantum corrections to the conductivity, such as weak-antilocalization. Recently, a rich variety of high-field magnetotransport properties in the regime of high electron densities (∼1019 cm−3) were reported, which can be related to additional two-dimensional layered conductivity, hampering the identification of the topological surface states. Here, we report that quantum corrections to the electronic conduction are dominated by the surface states for a semiconducting case, which can be analyzed by the Hikami-Larkin-Nagaoka model for two coupled surfaces in the case of strong spin-orbit interaction. However, in the metallic-like case this analysis fails and additional two-dimensional contributions need to be accounted for. Shubnikov-de Haas oscillations and quantized Hall resistance prove as strong indications for the two-dimensional layered metallic behavior. Temperature-dependent magnetotransport properties of high-quality Bi2Se3 single crystalline exfoliated macro and micro flakes are combined with high resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy, confirming the structure and stoichiometry. Angle-resolved photoemission spectroscopy proves a single-Dirac-cone surface state and a well-defined bulk band gap in topological insulating state. Spatially resolved core-level photoelectron microscopy demonstrates the surface stability. PMID:27270569
New DMSP Database of Precipitating Auroral Electrons and Ions.
Redmon, Robert J; Denig, William F; Kilcommons, Liam M; Knipp, Delores J
2017-08-01
Since the mid 1970's, the Defense Meteorological Satellite Program (DMSP) spacecraft have operated instruments for monitoring the space environment from low earth orbit. As the program evolved, so to have the measurement capabilities such that modern DMSP spacecraft include a comprehensive suite of instruments providing estimates of precipitating electron and ion fluxes, cold/bulk plasma composition and moments, the geomagnetic field, and optical emissions in the far and extreme ultraviolet. We describe the creation of a new public database of precipitating electrons and ions from the Special Sensor J (SSJ) instrument, complete with original counts, calibrated differential fluxes adjusted for penetrating radiation, estimates of the total kinetic energy flux and characteristic energy, uncertainty estimates, and accurate ephemerides. These are provided in a common and self-describing format that covers 30+ years of DMSP spacecraft from F06 (launched in 1982) through F18 (launched in 2009). This new database is accessible at the National Centers for Environmental Information (NCEI) and the Coordinated Data Analysis Web (CDAWeb). We describe how the new database is being applied to high latitude studies of: the co-location of kinetic and electromagnetic energy inputs, ionospheric conductivity variability, field aligned currents and auroral boundary identification. We anticipate that this new database will support a broad range of space science endeavors from single observatory studies to coordinated system science investigations.
Wu, Chia-Yi; Chang, Chin-Kuo; Robson, Debbie; Jackson, Richard; Chen, Shaw-Ji; Hayes, Richard D; Stewart, Robert
2013-01-01
High smoking prevalence is a major public health concern for people with mental disorders. Improved monitoring could be facilitated through electronic health record (EHR) databases. We evaluated whether EHR information held in structured fields might be usefully supplemented by open-text information. The prevalence and correlates of EHR-derived current smoking in people with severe mental illness were also investigated. All cases had been referred to a secondary mental health service between 2008-2011 and received a diagnosis of schizophreniform or bipolar disorder. The study focused on those aged over 15 years who had received active care from the mental health service for at least a year (N=1,555). The 'CRIS-IE-Smoking' application used General Architecture for Text Engineering (GATE) natural language processing software to extract smoking status information from open-text fields. A combination of CRIS-IE-Smoking with data from structured fields was evaluated for coverage and the prevalence and demographic correlates of current smoking were analysed. Proportions of patients with recorded smoking status increased from 11.6% to 64.0% through supplementing structured fields with CRIS-IE-Smoking data. The prevalence of current smoking was 59.6% in these 995 cases for whom this information was available. After adjustment, younger age (below 65 years), male sex, and non-cohabiting status were associated with current smoking status. A natural language processing application substantially improved routine EHR data on smoking status above structured fields alone and could thus be helpful in improving monitoring of this lifestyle behaviour. However, limited information on smoking status remained a challenge.
21 CFR 880.2910 - Clinical electronic thermometer.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Clinical electronic thermometer. 880.2910 Section... Monitoring Devices § 880.2910 Clinical electronic thermometer. (a) Identification. A clinical electronic... with an electronic signal amplification, conditioning, and display unit. The transducer may be in a...
21 CFR 880.2910 - Clinical electronic thermometer.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Clinical electronic thermometer. 880.2910 Section... Monitoring Devices § 880.2910 Clinical electronic thermometer. (a) Identification. A clinical electronic... with an electronic signal amplification, conditioning, and display unit. The transducer may be in a...
21 CFR 880.2910 - Clinical electronic thermometer.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Clinical electronic thermometer. 880.2910 Section... Monitoring Devices § 880.2910 Clinical electronic thermometer. (a) Identification. A clinical electronic... with an electronic signal amplification, conditioning, and display unit. The transducer may be in a...
21 CFR 880.2910 - Clinical electronic thermometer.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Clinical electronic thermometer. 880.2910 Section... Monitoring Devices § 880.2910 Clinical electronic thermometer. (a) Identification. A clinical electronic... with an electronic signal amplification, conditioning, and display unit. The transducer may be in a...
21 CFR 880.2910 - Clinical electronic thermometer.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Clinical electronic thermometer. 880.2910 Section... Monitoring Devices § 880.2910 Clinical electronic thermometer. (a) Identification. A clinical electronic... with an electronic signal amplification, conditioning, and display unit. The transducer may be in a...
Flores, M; Wajnberg, E; Bemski, G
2000-01-01
Electron nuclear double resonance (ENDOR) spectroscopy has been used to study protons in nitrosyl horse heart myoglobin (MbNO). (1)H ENDOR spectra were recorded for different settings of the magnetic field. Detailed analysis of the ENDOR powder spectra, using computer simulation, based on the "orientation-selection" principle, leads to the identification of the available protons in the heme pocket. We observe hyperfine interactions of the N(HisF8)-Fe(2+)-N(NO) complex with five protons in axial and with eight protons in the rhombic symmetry along different orientations, including those of the principal axes of the g-tensor. Protons from His-E7 and Val-E11 residues are identified in the two symmetries, rhombic and axial, exhibited by MbNO. Our results indicate that both residues are present inside the heme pocket and help to stabilize one particular conformation. PMID:10733988
Development of TPF-1 plasma focus for education
NASA Astrophysics Data System (ADS)
Picha, R.; Promping, J.; Channuie, J.; Poolyarat, N.; Sangaroon, S.; Traikool, T.
2017-09-01
The plasma focus is a device that uses high voltage and electromagnetic force to induce plasma generation and acceleration, in order to cause nuclear reactions. Radiation of various types (X-ray, gamma ray, electrons, ions, neutrons) can be generated using this method during the pinch phase, thus making the plasma focus able to serve as a radiation source. Material testing, modification, and identification are among the current applications of the plasma focus. Other than being an alternative option to isotopic sources, the plasma focus, which requires multidisciplinary team of personnel to design, operate, and troubleshoot, can also serve as an excellent learning device for physics and engineering students in the fields including, but not limited to, plasma physics, nuclear physics, electronics engineering, and mechanical engineering. This work describes the parameters and current status of Thai Plasma Focus 1 (TPF-1) and the characteristics of the plasma being produced in the machine using a Rogowski coil.
Weed Identification Field Training Demonstrations.
ERIC Educational Resources Information Center
Murdock, Edward C.; And Others
1986-01-01
Reviews efforts undertaken in weed identification field training sessions for agriprofessionals in South Carolina. Data over a four year period (1980-1983) revealed that participants showed significant improvement in their ability to identify weeds. Reaffirms the value of the field demonstration technique. (ML)
NASA Astrophysics Data System (ADS)
Choi, Jung Bum
Far infrared (FIR) magneto-transmission studies of n-type Hg_{1-x}Cd _{x}Te (x = 0.198, 0.204, 0.224, 0.237, 0.270) for temperatures down to 1.5K and magnetic fields up to 9T in Voigt and Faraday geometries have been performed. Magneto-optical transitions of donor bound electrons are observed; including the (000) --> (001) and (010) --> (01k_{z}) in the Voigt geometry, and the (000) --> (110) in the Faraday geometry. These identifications are confirmed by their resonance positions, selection rules, and temperature dependence. The experimental observations are consistent with calculations of resonance positions and lineshapes based on the hydrogenic donor model including central cell effects. This work confirms the donor bound electronic ground state for Hg_{1-x}Cd_{x} Te. The magneto-transport and FIR spectroscopy have been combined to probe the nature of the impurity band in the vicinity of the magnetic field induced metal-insulator transition. The results obtained in Hg_ {1-x}Cd_{x}Te and InSb show the persistance of the (000) --> (110) impurity transition through the metal-insulator critical field. This observation demonstrates the existence of the metallic impurity band which is split off from the conduction band. In the studies of the critical behavior of InSb, the conductivity measured for temperatures down to 0.45K shows a dominant linear dependence on temperature near the transition field. Furthermore, the zero-temperature extrapolated conductivity was found to drop continuously to zero at the transition field with a critical exponent of nu = 1.07 +/- 0.07.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sachan, Ritesh; Zhang, Yanwen; Ou, Xin
Here we demonstrate the enhanced imaging capabilities of an aberration corrected scanning transmission electron microscope to advance the understanding of ion track structure in pyrochlore structured materials (i.e., Gd 2Ti 2O 7 and Gd 2TiZrO 7). Track formation occurs due to the inelastic transfer of energy from incident ions to electrons, and atomic-level details of track morphology as a function of energy-loss are revealed in the present work. A comparison of imaging details obtained by varying collection angles of detectors is discussed in the present work. A quantitative analysis of phase identification using high-angle annular dark field imaging is performedmore » on the ion tracks. Finally, a novel 3-dimensional track reconstruction method is provided that is based on depth dependent imaging of the ion tracks. The technique is used in extracting the atomic-level details of nanoscale features, such as the disordered ion tracks, which are embedded in relatively thicker matrix. Another relevance of the method is shown by measuring the tilt of the ion tracks relative to the electron beam incidence that helps in knowing the structure and geometry of ion tracks quantitatively.« less
Sachan, Ritesh; Zhang, Yanwen; Ou, Xin; ...
2016-12-13
Here we demonstrate the enhanced imaging capabilities of an aberration corrected scanning transmission electron microscope to advance the understanding of ion track structure in pyrochlore structured materials (i.e., Gd 2Ti 2O 7 and Gd 2TiZrO 7). Track formation occurs due to the inelastic transfer of energy from incident ions to electrons, and atomic-level details of track morphology as a function of energy-loss are revealed in the present work. A comparison of imaging details obtained by varying collection angles of detectors is discussed in the present work. A quantitative analysis of phase identification using high-angle annular dark field imaging is performedmore » on the ion tracks. Finally, a novel 3-dimensional track reconstruction method is provided that is based on depth dependent imaging of the ion tracks. The technique is used in extracting the atomic-level details of nanoscale features, such as the disordered ion tracks, which are embedded in relatively thicker matrix. Another relevance of the method is shown by measuring the tilt of the ion tracks relative to the electron beam incidence that helps in knowing the structure and geometry of ion tracks quantitatively.« less
Sugimoto, K; Williamson, R E; Wasteneys, G O
2000-12-01
This article explores root epidermal cell elongation and its dependence on two structural elements of cells, cortical microtubules and cellulose microfibrils. The recent identification of Arabidopsis morphology mutants with putative cell wall or cytoskeletal defects demands a procedure for examining and comparing wall architecture and microtubule organization patterns in this species. We developed methods to examine cellulose microfibrils by field emission scanning electron microscopy and microtubules by immunofluorescence in essentially intact roots. We were able to compare cellulose microfibril and microtubule alignment patterns at equivalent stages of cell expansion. Field emission scanning electron microscopy revealed that Arabidopsis root epidermal cells have typical dicot primary cell wall structure with prominent transverse cellulose microfibrils embedded in pectic substances. Our analysis showed that microtubules and microfibrils have similar orientation only during the initial phase of elongation growth. Microtubule patterns deviate from a predominantly transverse orientation while cells are still expanding, whereas cellulose microfibrils remain transverse until well after expansion finishes. We also observed microtubule-microfibril alignment discord before cells enter their elongation phase. This study and the new technology it presents provide a starting point for further investigations on the physical properties of cell walls and their mechanisms of assembly.
Diagnostic electron microscopy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dickersin, G.R.
1988-01-01
In this book the author presents a comprehensive reference text on diagnostic electron microscopy. Throughout the book he illustrates how ultrastructural identification can be helpful for the recognition of cell type and the identification of mechanisms of pathogenesis in various diseases. In addition to electron microscopy photographs, there are also numerous light microscopy photographs for comparison. This text presents the classification of neoplasms in the order and arrangement most familiar to the pathologist. Contents: Introduction; Diagram of a Normal Cell; Normal Cell Function; Embryology; Neoplasms; Infectious Agents; Metabolic Diseases; Renal Diseases; Skeletal Muscle and Peripheral Nerve Diseases; Index.
Radio frequency diodes and circuits fabricated via adhesion lithography (Conference Presentation)
NASA Astrophysics Data System (ADS)
Georgiadou, Dimitra G.; Semple, James; Wyatt-Moon, Gwenhivir; Anthopoulos, Thomas D.
2016-09-01
The commercial interest in Radio Frequency Identification (RFID) tags keeps growing, as new application sectors, spanning from healthcare to electronic article surveillance (EAS) and personal identification, are constantly emerging for these types of electronic devices. The increasing demand for the so-called "smart labels" necessitates their high throughput manufacturing, and indeed on thin flexible substrates, that will reduce the cost and render them competitive to the currently widely employed barcodes. Adhesion Lithography (a-Lith) is a novel patterning technique that allows the facile high yield fabrication of co-planar large aspect ratio (<100,000) metal electrodes separated by a sub-20 nm gap on large area substrates of any type. Deposition of high mobility semiconductors from their solution at low, compatible with plastic substrates, temperatures and application of specific processing protocols can dramatically improve the performance of the fabricated Schottky diodes. It will be shown that in this manner both organic and inorganic high speed diodes and rectifiers can be obtained, operating at frequencies much higher than the 13.56 MHz benchmark, currently employed in passive RFID tags and near filed communications (NFC). This showcases the universality of this method towards fabricating high speed p- and n-type diodes, irrespective of the substrate, simply based on the extreme downscaling of key device dimensions obtained in these nanoscale structures. The potential for scaling up this technique at low cost, combined with the significant performance optimisation and improved functionality that can be attained through intelligent material selection, render a-Lith unique within the field of plastic electronics.
Approach to identifying pollutant source and matching flow field
NASA Astrophysics Data System (ADS)
Liping, Pang; Yu, Zhang; Hongquan, Qu; Tao, Hu; Wei, Wang
2013-07-01
Accidental pollution events often threaten people's health and lives, and it is necessary to identify a pollutant source rapidly so that prompt actions can be taken to prevent the spread of pollution. But this identification process is one of the difficulties in the inverse problem areas. This paper carries out some studies on this issue. An approach using single sensor information with noise was developed to identify a sudden continuous emission trace pollutant source in a steady velocity field. This approach first compares the characteristic distance of the measured concentration sequence to the multiple hypothetical measured concentration sequences at the sensor position, which are obtained based on a source-three-parameter multiple hypotheses. Then we realize the source identification by globally searching the optimal values with the objective function of the maximum location probability. Considering the large amount of computation load resulting from this global searching, a local fine-mesh source search method based on priori coarse-mesh location probabilities is further used to improve the efficiency of identification. Studies have shown that the flow field has a very important influence on the source identification. Therefore, we also discuss the impact of non-matching flow fields with estimation deviation on identification. Based on this analysis, a method for matching accurate flow field is presented to improve the accuracy of identification. In order to verify the practical application of the above method, an experimental system simulating a sudden pollution process in a steady flow field was set up and some experiments were conducted when the diffusion coefficient was known. The studies showed that the three parameters (position, emission strength and initial emission time) of the pollutant source in the experiment can be estimated by using the method for matching flow field and source identification.
Technical Competencies Applied in Experimental Fluid Dynamics
NASA Astrophysics Data System (ADS)
Tagg, Randall
2017-11-01
The practical design, construction, and operation of fluid dynamics experiments require a broad range of competencies. Three types are instrumental, procedural, and design. Respective examples would be operation of a spectrum analyzer, soft-soldering or brazing flow plumbing, and design of a small wind tunnel. Some competencies, such as the selection and installation of pumping systems, are unique to fluid dynamics and fluids engineering. Others, such as the design and construction of electronic amplifiers or optical imaging systems, overlap with other fields. Thus the identification and development of learning materials and methods for instruction are part of a larger effort to identify competencies needed in active research and technical innovation.
The Mu2e undoped CsI crystal calorimeter
DOE Office of Scientific and Technical Information (OSTI.GOV)
Atanov, N.; Baranov, V.; Budagov, J.
We present the Mu2e experiment at Fermilab will search for Charged Lepton Flavor Violating conversion of a muon to an electron in an atomic field. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter and an external system, surrounding the solenoid, to veto cosmic rays. The calorimeter plays an important role to provide: a) excellent particle identification capabilities; b) a fast trigger filter; c) an easier tracker track reconstruction. Two disks, located downstream of the tracker, contain 674 pure CsI crystals each. Each crystal is read out by two arrays of UV-extended SiPMs. The choice of the crystalsmore » and SiPMs has been finalized after a thorough test campaign. A first small scale prototype consisting of 51 crystals and 102 SiPM arrays has been exposed to an electron beam at the BTF (Beam Test Facility) in Frascati. Lastly, although the readout electronics were not final, results show that the current design is able to meet the timing and energy resolution required by the Mu2e experiment.« less
The Mu2e undoped CsI crystal calorimeter
Atanov, N.; Baranov, V.; Budagov, J.; ...
2018-02-22
We present the Mu2e experiment at Fermilab will search for Charged Lepton Flavor Violating conversion of a muon to an electron in an atomic field. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter and an external system, surrounding the solenoid, to veto cosmic rays. The calorimeter plays an important role to provide: a) excellent particle identification capabilities; b) a fast trigger filter; c) an easier tracker track reconstruction. Two disks, located downstream of the tracker, contain 674 pure CsI crystals each. Each crystal is read out by two arrays of UV-extended SiPMs. The choice of the crystalsmore » and SiPMs has been finalized after a thorough test campaign. A first small scale prototype consisting of 51 crystals and 102 SiPM arrays has been exposed to an electron beam at the BTF (Beam Test Facility) in Frascati. Lastly, although the readout electronics were not final, results show that the current design is able to meet the timing and energy resolution required by the Mu2e experiment.« less
Waste processing: new near infrared technologies for material identification and selection
NASA Astrophysics Data System (ADS)
Cesetti, M.; Nicolosi, P.
2016-09-01
The awareness of environmental issues on a global scale increases the opportunities for waste handling companies. Recovery is set to become all the more important in areas such as waste selection, minerals processing, electronic scrap, metal and plastic recycling, refuse and the food industry. Effective recycling relies on effective sorting. Sorting is a fundamental step of the waste disposal/recovery process. The big players in the sorting market are pushing for the development of new technologies to cope with literally any type of waste. The purpose of this tutorial is to gain an understanding of waste management, frameworks, strategies, and components that are current and emerging in the field. A particular focus is given to spectroscopic techniques that pertains the material selection process with a greater emphasis placed on the NIR technology for material identification. Three different studies that make use of NIR technology are shown, they are an example of some of the possible applications and the excellent results that can be achieved with this technique.
Two methods for transmission line simulation model creation based on time domain measurements
NASA Astrophysics Data System (ADS)
Rinas, D.; Frei, S.
2011-07-01
The emission from transmission lines plays an important role in the electromagnetic compatibility of automotive electronic systems. In a frequency range below 200 MHz radiation from cables is often the dominant emission factor. In higher frequency ranges radiation from PCBs and their housing becomes more relevant. Main sources for this emission are the conducting traces. The established field measurement methods according CISPR 25 for evaluation of emissions suffer from the need to use large anechoic chambers. Furthermore measurement data can not be used for simulation model creation in order to compute the overall fields radiated from a car. In this paper a method to determine the far-fields and a simulation model of radiating transmission lines, esp. cable bundles and conducting traces on planar structures, is proposed. The method measures the electromagnetic near-field above the test object. Measurements are done in time domain in order to get phase information and to reduce measurement time. On the basis of near-field data equivalent source identification can be done. Considering correlations between sources along each conductive structure in model creation process, the model accuracy increases and computational costs can be reduced.
Cousin, Xavier; Daouk, Tarek; Péan, Samuel; Lyphout, Laura; Schwartz, Marie-Elise; Bégout, Marie-Laure
2012-08-15
Although individual electronic tagging using passive integrated acoustic (PIT) tags is established, it is mainly for fish >60 mm in length and is unsuitable for fish of <30 mm, like zebrafish. We used radio frequency identification (RFID) microtags (1 mm in diameter and 6 mm in length, with a mass of ~10 mg) to individually identify juvenile zebrafish (length 16-42 mm, mass 138-776 mg) for the first time, and studied the effects of intracoelomic implantation on fish survival and microtag loss, growth, spawning and exploratory behaviour. After 5.5 months, both high survival (82%) and low microtag loss (11%) were achieved. The smallest surviving fish weighed 178 mg, and success in microtag reading was 73% for the size class 350-450 mg (26 mm). Greater success was achieved when fish were larger at the time of tagging but no negative effects on growth were observed for any size class and some tagged fish spawned. No significant differences in behavioural responses could be detected between tagged fish and untagged controls after 2 months. Overall, the results suggest that the tagging method is highly suitable for fish as small as zebrafish juveniles. We think this method will provide significant advances for researchers of the ever-growing fish model community and more generally for all small-fish users. Tagging is essential when one needs to identify fish (e.g. particular genotypes with no external cue), to run longitudinal monitoring of individual biological traits (e.g. growth) or to repeat assays with the same individual at discrete points in time (e.g. behaviour studies). Such a method will find applications in physiology, genetics, behaviour and (eco)toxicology fields.
Wells, Gary L
2008-02-01
The Illinois pilot program on lineup procedures has helped sharpen the focus on the types of controls that are needed in eyewitness field experiments and the limits that exist for interpreting outcome measures (rates of suspect and filler identifications). A widely-known limitation of field experiments is that, unlike simulated crime experiments, the guilt or innocence of the suspects is not easily known independently of the behavior of the eyewitnesses. Less well appreciated is that the rate of identification of lineup fillers, although clearly errors, can be a misleading measure if the filler identification rate is used to assess which of two or more lineup procedures is the better procedure. Several examples are used to illustrate that there are clearly improper procedures that would yield fewer identifications of fillers than would their proper counterparts. For example, biased lineup structure (e.g., using poorly matched fillers) as well as suggestive lineup procedures (that can result from non-blind administration of lineups) would reduce filler identification errors compared to unbiased and non-suggestive procedures. Hence, under many circumstances filler identification rates can be misleading indicators of preferred methods. Comparisons of lineup procedures in future field experiments will not be easily accepted in the absence of double-blind administration methods in all conditions plus true random assignment to conditions.
Electron-Muon Identification by Atmospheric Shower and Electron Beam in a New EAS Detector Concept
NASA Astrophysics Data System (ADS)
Iori, M.; Denizli, H.; Yilmaz, A.; Ferrarotto, F.; Russ, J.
2015-03-01
We present results demonstrating the time resolution and μ/e separation capabilities of a new concept for an EAS detector capable of measuring cosmic rays arriving with large zenith angles. This kind of detector has been designed to be part of a large area (several square kilometer) surface array designed to measure ultra high energy (10-200 PeV) τ neutrinos using the Earth-skimming technique. A criterion to identify electron-gammas is also shown and the particle identification capability is tested by measurements in coincidence with the KASKADE-GRANDE experiment in Karlsruhe, Germany.
NASA Astrophysics Data System (ADS)
Kukla, D.; Brynk, T.; Pakieła, Z.
2017-08-01
This work presents the results of fatigue tests of MAR 247 alloy flat specimens with aluminides layers of 20 or 40 µm thickness obtained in CVD process. Fatigue test was conducted at amplitude equal to half of maximum load and ranging between 300 and 650 MPa (stress asymmetry ratio R = 0, frequency f = 20 Hz). Additionally, 4 of the tests, characterized by the highest amplitude, were accompanied with non-contact strain field measurements by means of electronic speckle pattern interferometry and digital image correlation. Results of these measurements allowed to localize the areas of deformation concentration identified as the damage points of the surface layer or advanced crack presence in core material. Identification and observation of the development of deformation in localization areas allowed to assess fatigue-related phenomena in both layer and substrate materials.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wilbois, Timo; Helm, Hanspeter
2011-11-15
Strong-field ionization of molecular hydrogen is studied at wavelengths ranging from 300 to 800 nm using pulses of 100-fs duration. We find that over this wide wavelength range, from nominally 4-photon to 11-photon ionization, resonance features dominate the ionization probability at intensities below 10{sup 14} W/cm{sup 2}. Photoelectron momentum maps recorded by an imaging spectrometer are analyzed to identify the wavelength-dependent ionization pathways in single ionization of molecular hydrogen. A number of models, some empirical, which are appropriate for a quantitative interpretation of the spectra and the ionization yield are introduced. A near-absolute comparison of measured ionization yields at 398more » nm is made with the predictions based on a numerical solution [Y. V. Vanne and A. Saenz, Phys. Rev. A 79, 023421 (2009)] of the time-dependent Schroedinger equation for two correlated electrons.« less
NASA Astrophysics Data System (ADS)
Eiichirou, Kawamori
2018-04-01
We report the observation of supercontinuum of Langmuir plasma waves, that exhibits broad power spectrum having significant spatio-temporal coherence grown from a monochromatic seed-wave, in one-dimensional particle-in-cell simulations. The Langmuir wave supercontinuum (LWSC) is formed when the seed wave excites side-band fields efficiently by the modulational instabilities. Its identification is achieved by the use of the tricoherence analysis, which detects four wave mixings (FWMs) of plasmons (plasma wave quanta), and evaluation of the first order coherence, which is a measure of temporal coherence, of the wave electric fields. The irreversible evolution to the coherent LWSC from the seed wave is realized by the wave-particle interactions causing stochastic electron motions in the phase space and the coherence of LWSC is maintained by the phase-preserving FWMs of plasmons. The LWSC corresponds to a quasi Bernstein-Greene-Kruskal mode.
METHOD AND APPARATUS FOR INJECTING AND TRAPPING ELECTRONS IN A MAGNETIC FIELD
Christofilos, N.C.
1962-05-29
An apparatus is designed for the manipulation of electrons in an exially symmetric magnetic field region and may be employed to trap electrons in such a field by directing an electron beam into a gradientially intensified field region therein to form an annular electron moving axially in the field and along a decreasing field gradient. Dissipative loop circuits such as resistive loops are disposed along at least the decreasing field gradient so as to be inductively coupled to the electron bunch so as to extract energy of the electron bunch and provide a braking force effective to reduce the velocity of the bunch. Accordingly, the electron bunch upon entering a lower intensity magnetic field region is retained therein since the electrons no longer possess sufficient energy to escape. (AEC)
NASA Astrophysics Data System (ADS)
Focsa, C.; Pinchemel, B.
1999-09-01
The dispersed laser-induced fluorescence technique has been applied for the first time to metallic molecular ions. The TiCl + and TiF + ions were produced by a high-voltage discharge in helium with traces of TiCl 4 or TiF 4. A c.w. dye-laser and a grating plate spectrometer were used to record low-resolution spectra of these species in the visible. This leads to the observation of new low-lying electronic states of these ions: the C 3Π (˜1535 cm -1) state of TiCl +, the B 3Δ (˜2040 cm -1) and C 3Π (˜2200 cm -1) states of TiF +. The identification of these new states contributes to a better characterisation of the first 3000 cm -1 of the energy level diagrams of these molecules. The experimental position of the C 3Π state of TiCl + is in good agreement with theoretical predictions given by a Ligand Field Theory model [C. Focsa, M. Bencheikh, L.G.M. Pettersson, J. Phys. B: At. Mol. Opt. Phys. 31 (1998) 2857]. We have extended these calculations to the TiF + isovalent ion, taking advantage of the new experimental data. Both experimental and theoretical new results presented in this paper are expected to help future investigations on these species.
Patient identification errors: the detective in the laboratory.
Salinas, Maria; López-Garrigós, Maite; Lillo, Rosa; Gutiérrez, Mercedes; Lugo, Javier; Leiva-Salinas, Carlos
2013-11-01
The eradication of errors regarding patients' identification is one of the main goals for safety improvement. As clinical laboratory intervenes in 70% of clinical decisions, laboratory safety is crucial in patient safety. We studied the number of Laboratory Information System (LIS) demographic data errors registered in our laboratory during one year. The laboratory attends a variety of inpatients and outpatients. The demographic data of outpatients is registered in the LIS, when they present to the laboratory front desk. The requests from the primary care centers (PCC) are made electronically by the general practitioner. A manual step is always done at the PCC to conciliate the patient identification number in the electronic request with the one in the LIS. Manual registration is done through hospital information system demographic data capture when patient's medical record number is registered in LIS. Laboratory report is always sent out electronically to the patient's electronic medical record. Daily, every demographic data in LIS is manually compared to the request form to detect potential errors. Fewer errors were committed when electronic order was used. There was great error variability between PCC when using the electronic order. LIS demographic data manual registration errors depended on patient origin and test requesting method. Even when using the electronic approach, errors were detected. There was a great variability between PCC even when using this electronic modality; this suggests that the number of errors is still dependent on the personnel in charge of the technology. © 2013.
21 CFR 886.4400 - Electronic metal locator.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electronic metal locator. 886.4400 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4400 Electronic metal locator. (a) Identification. An electronic metal locator is an AC-powered device with probes intended to locate metallic...
21 CFR 886.4400 - Electronic metal locator.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electronic metal locator. 886.4400 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4400 Electronic metal locator. (a) Identification. An electronic metal locator is an AC-powered device with probes intended to locate metallic...
21 CFR 886.4400 - Electronic metal locator.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electronic metal locator. 886.4400 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4400 Electronic metal locator. (a) Identification. An electronic metal locator is an AC-powered device with probes intended to locate metallic...
21 CFR 886.4400 - Electronic metal locator.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electronic metal locator. 886.4400 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4400 Electronic metal locator. (a) Identification. An electronic metal locator is an AC-powered device with probes intended to locate metallic...
21 CFR 886.4400 - Electronic metal locator.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electronic metal locator. 886.4400 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4400 Electronic metal locator. (a) Identification. An electronic metal locator is an AC-powered device with probes intended to locate metallic...
How to locate and appraise qualitative research in complementary and alternative medicine
2013-01-01
Background The aim of this publication is to present a case study of how to locate and appraise qualitative studies for the conduct of a meta-ethnography in the field of complementary and alternative medicine (CAM). CAM is commonly associated with individualized medicine. However, one established scientific approach to the individual, qualitative research, thus far has been explicitly used very rarely. This article demonstrates a case example of how qualitative research in the field of CAM studies was identified and critically appraised. Methods Several search terms and techniques were tested for the identification and appraisal of qualitative CAM research in the conduct of a meta-ethnography. Sixty-seven electronic databases were searched for the identification of qualitative CAM trials, including CAM databases, nursing, nutrition, psychological, social, medical databases, the Cochrane Library and DIMDI. Results 9578 citations were screened, 223 articles met the pre-specified inclusion criteria, 63 full text publications were reviewed, 38 articles were appraised qualitatively and 30 articles were included. The search began with PubMed, yielding 87% of the included publications of all databases with few additional relevant findings in the specific databases. CINHAL and DIMDI also revealed a high number of precise hits. Although CAMbase and CAM-QUEST® focus on CAM research only, almost no hits of qualitative trials were found there. Searching with broad text terms was the most effective search strategy in all databases. Conclusions This publication presents a case study on how to locate and appraise qualitative studies in the field of CAM. The example shows that the literature search for qualitative studies in the field of CAM is most effective when the search is begun in PubMed followed by CINHAL or DIMDI using broad text terms. Exclusive CAM databases delivered no additional findings to locate qualitative CAM studies. PMID:23731997
How to locate and appraise qualitative research in complementary and alternative medicine.
Franzel, Brigitte; Schwiegershausen, Martina; Heusser, Peter; Berger, Bettina
2013-06-03
The aim of this publication is to present a case study of how to locate and appraise qualitative studies for the conduct of a meta-ethnography in the field of complementary and alternative medicine (CAM). CAM is commonly associated with individualized medicine. However, one established scientific approach to the individual, qualitative research, thus far has been explicitly used very rarely. This article demonstrates a case example of how qualitative research in the field of CAM studies was identified and critically appraised. Several search terms and techniques were tested for the identification and appraisal of qualitative CAM research in the conduct of a meta-ethnography. Sixty-seven electronic databases were searched for the identification of qualitative CAM trials, including CAM databases, nursing, nutrition, psychological, social, medical databases, the Cochrane Library and DIMDI. 9578 citations were screened, 223 articles met the pre-specified inclusion criteria, 63 full text publications were reviewed, 38 articles were appraised qualitatively and 30 articles were included. The search began with PubMed, yielding 87% of the included publications of all databases with few additional relevant findings in the specific databases. CINHAL and DIMDI also revealed a high number of precise hits. Although CAMbase and CAM-QUEST® focus on CAM research only, almost no hits of qualitative trials were found there. Searching with broad text terms was the most effective search strategy in all databases. This publication presents a case study on how to locate and appraise qualitative studies in the field of CAM. The example shows that the literature search for qualitative studies in the field of CAM is most effective when the search is begun in PubMed followed by CINHAL or DIMDI using broad text terms. Exclusive CAM databases delivered no additional findings to locate qualitative CAM studies.
Wu, Chia-Yi; Chang, Chin-Kuo; Robson, Debbie; Jackson, Richard; Chen, Shaw-Ji; Hayes, Richard D.; Stewart, Robert
2013-01-01
Background High smoking prevalence is a major public health concern for people with mental disorders. Improved monitoring could be facilitated through electronic health record (EHR) databases. We evaluated whether EHR information held in structured fields might be usefully supplemented by open-text information. The prevalence and correlates of EHR-derived current smoking in people with severe mental illness were also investigated. Methods All cases had been referred to a secondary mental health service between 2008-2011 and received a diagnosis of schizophreniform or bipolar disorder. The study focused on those aged over 15 years who had received active care from the mental health service for at least a year (N=1,555). The ‘CRIS-IE-Smoking’ application used General Architecture for Text Engineering (GATE) natural language processing software to extract smoking status information from open-text fields. A combination of CRIS-IE-Smoking with data from structured fields was evaluated for coverage and the prevalence and demographic correlates of current smoking were analysed. Results Proportions of patients with recorded smoking status increased from 11.6% to 64.0% through supplementing structured fields with CRIS-IE-Smoking data. The prevalence of current smoking was 59.6% in these 995 cases for whom this information was available. After adjustment, younger age (below 65 years), male sex, and non-cohabiting status were associated with current smoking status. Conclusions A natural language processing application substantially improved routine EHR data on smoking status above structured fields alone and could thus be helpful in improving monitoring of this lifestyle behaviour. However, limited information on smoking status remained a challenge. PMID:24069288
De-identification of clinical notes via recurrent neural network and conditional random field.
Liu, Zengjian; Tang, Buzhou; Wang, Xiaolong; Chen, Qingcai
2017-11-01
De-identification, identifying information from data, such as protected health information (PHI) present in clinical data, is a critical step to enable data to be shared or published. The 2016 Centers of Excellence in Genomic Science (CEGS) Neuropsychiatric Genome-scale and RDOC Individualized Domains (N-GRID) clinical natural language processing (NLP) challenge contains a de-identification track in de-identifying electronic medical records (EMRs) (i.e., track 1). The challenge organizers provide 1000 annotated mental health records for this track, 600 out of which are used as a training set and 400 as a test set. We develop a hybrid system for the de-identification task on the training set. Firstly, four individual subsystems, that is, a subsystem based on bidirectional LSTM (long-short term memory, a variant of recurrent neural network), a subsystem-based on bidirectional LSTM with features, a subsystem based on conditional random field (CRF) and a rule-based subsystem, are used to identify PHI instances. Then, an ensemble learning-based classifiers is deployed to combine all PHI instances predicted by above three machine learning-based subsystems. Finally, the results of the ensemble learning-based classifier and the rule-based subsystem are merged together. Experiments conducted on the official test set show that our system achieves the highest micro F1-scores of 93.07%, 91.43% and 95.23% under the "token", "strict" and "binary token" criteria respectively, ranking first in the 2016 CEGS N-GRID NLP challenge. In addition, on the dataset of 2014 i2b2 NLP challenge, our system achieves the highest micro F1-scores of 96.98%, 95.11% and 98.28% under the "token", "strict" and "binary token" criteria respectively, outperforming other state-of-the-art systems. All these experiments prove the effectiveness of our proposed method. Copyright © 2017. Published by Elsevier Inc.
NASA Astrophysics Data System (ADS)
Ji, H.; Yoo, J.; Dorfman, S. E.; Jara-Almonte, J.; Yamada, M.; Swanson, C.; Daughton, W. S.; Roytershteyn, V.; Kuwahata, A.; Ii, T.; Inomoto, M.; Ono, Y.; von Stechow, A.; Grulke, O.; Phan, T.; Mozer, F.; Bale, S. D.
2013-12-01
Despite its disruptive influences on the large-scale structures of space and solar plasmas, the crucial topological changes and associated dissipation during magnetic reconnection take place only near an X-line within thin singular layers. In the modern collisionless models where electrons and ions are allowed to move separately, it has been predicted that ions exhaust efficiently through a thicker, ion-scale dissipative layer while mobile electrons can evacuate through a thinner, electron-scale dissipation layer, allowing for efficient release of magnetic energy. While ion dissipation layers have been frequently detected, the existence of election layers near the X-line and the associated dissipation structures and mechanisms are still an open question, and will be a main subject of the coming MMS mission. In this presentation, we will summarize our efforts in the past a few years to study electron-scale dissipation in a well-controlled and well-diagnosed reconnecting current sheet in a laboratory plasma, with close comparisons with the state-of-the-art, 2D and 3D fully kinetic simulations. Key results include: (1) positive identification of electromagnetic waves detected at the current sheet center as long wave-length, lower-hybrid drift instabilities (EM-LHDI), (2) however, there is strong evidence that this EM-LHDI cannot provide the required force to support the reconnection electric field, (3) detection of 3D flux-rope-like magnetic structures during impulsive reconnection events, and (4) electrons are heated through non-classical mechanisms near the X-line with a small but clear temperature anisotropy. These results, unfortunately, do not resolve the outstanding discrepancies on electron layer thickness between best available experiments and fully kinetic simulations. To make further progress, we are continuously pushing in the both experimental and numerical frontiers. Experimentally, we started investigations on EM-LHDI and electron heating as a function of guide field strength and symmetry of reconnection geometry, with new attempts to measure non-thermal electrons and higher frequency fluctuations. Numerically, we started investigations of kinetic simulations at realistic ratios of electron plasma frequency to cyclotron frequency, and also at realistic ratios of ion mass to electron mass. The most updated results of these new projects will be presented with discussions on the relevance to space observations.
21 CFR 886.5900 - Electronic vision aid.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electronic vision aid. 886.5900 Section 886.5900...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5900 Electronic vision aid. (a) Identification. An electronic vision aid is an AC-powered or battery-powered device that consists of an...
21 CFR 886.5900 - Electronic vision aid.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electronic vision aid. 886.5900 Section 886.5900...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5900 Electronic vision aid. (a) Identification. An electronic vision aid is an AC-powered or battery-powered device that consists of an...
21 CFR 886.5900 - Electronic vision aid.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electronic vision aid. 886.5900 Section 886.5900...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5900 Electronic vision aid. (a) Identification. An electronic vision aid is an AC-powered or battery-powered device that consists of an...
21 CFR 886.5900 - Electronic vision aid.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electronic vision aid. 886.5900 Section 886.5900...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5900 Electronic vision aid. (a) Identification. An electronic vision aid is an AC-powered or battery-powered device that consists of an...
21 CFR 886.5900 - Electronic vision aid.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electronic vision aid. 886.5900 Section 886.5900...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5900 Electronic vision aid. (a) Identification. An electronic vision aid is an AC-powered or battery-powered device that consists of an...
21 CFR 880.2420 - Electronic monitor for gravity flow infusion systems.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electronic monitor for gravity flow infusion... and Personal Use Monitoring Devices § 880.2420 Electronic monitor for gravity flow infusion systems. (a) Identification. An electronic monitor for gravity flow infusion systems is a device used to...
21 CFR 880.2420 - Electronic monitor for gravity flow infusion systems.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electronic monitor for gravity flow infusion... and Personal Use Monitoring Devices § 880.2420 Electronic monitor for gravity flow infusion systems. (a) Identification. An electronic monitor for gravity flow infusion systems is a device used to...
21 CFR 880.2420 - Electronic monitor for gravity flow infusion systems.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electronic monitor for gravity flow infusion... and Personal Use Monitoring Devices § 880.2420 Electronic monitor for gravity flow infusion systems. (a) Identification. An electronic monitor for gravity flow infusion systems is a device used to...
21 CFR 880.2420 - Electronic monitor for gravity flow infusion systems.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electronic monitor for gravity flow infusion... and Personal Use Monitoring Devices § 880.2420 Electronic monitor for gravity flow infusion systems. (a) Identification. An electronic monitor for gravity flow infusion systems is a device used to...
21 CFR 880.2420 - Electronic monitor for gravity flow infusion systems.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electronic monitor for gravity flow infusion... and Personal Use Monitoring Devices § 880.2420 Electronic monitor for gravity flow infusion systems. (a) Identification. An electronic monitor for gravity flow infusion systems is a device used to...
Eyewitness identification in actual criminal cases: an archival analysis.
Behrman, B W; Davey, S L
2001-10-01
This study analyzed 271 actual police cases in order to address several prevalent issues in the eyewitness literature. Suspect identification (SI) rates were obtained for 289 photographic lineups, 258 field showups, 58 live lineups, and 66 lineup identifications preceded by earlier identifications. SI rates were assessed for 3 levels of extrinsic evidence: no extrinsic evidence, evidence of minimal probative value, and evidence of substantial probative value. The SI rates for the photographic lineups were assessed as a function of delay, same vs. cross-race conditions, witness type, and weapon presence. SI rates declined significantly over time; SI rates were significantly greater for the same-race condition. SI rates were much greater for field showups than photographic lineups, 76% vs. 48%. The SI rates for the field showups did not vary as a function of eyewitness conditions. The relation between confidence and suspect/foil identifications for the live lineups was significant and moderately high. The utility of archival identification studies for eyewitness testimony research is discussed.
NASA Astrophysics Data System (ADS)
Singh Ghotra, Harjit; Kant, Niti
2018-06-01
We examine the electron dynamics during laser-cluster interaction. In addition to the electrostatic field of an individual cluster and laser field, we consider an external transverse wiggler magnetic field, which plays a pivotal role in enhancing the electron acceleration. Single-particle simulation has been presented with a short pulse linearly polarized as well as circularly polarized laser pulses for electron acceleration in a cluster. The persisting Coulomb field allows the electron to absorb energy from the laser field. The stochastically heated electron finds a weak electric field at the edge of the cluster from where it is ejected. The wiggler magnetic field connects the regions of the stochastically heated, ejected electron from the cluster and high energy gain by the electron from the laser field outside the cluster. This increases the field strength and hence supports the electron to meet the phase of the laser field for enhanced acceleration. A long duration resonance appears with an optimized magnetic wiggler field of about 3.4 kG. Hence, the relativistic energy gain by the electron is enhanced up to a few 100 MeV with an intense short pulse laser with an intensity of about 1019 W cm‑2 in the presence of a wiggler magnetic field.
Unbalanced field RF electron gun
Hofler, Alicia
2013-11-12
A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.
27 CFR 73.12 - What security controls must I use for identification codes and passwords?
Code of Federal Regulations, 2010 CFR
2010-04-01
... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false What security controls... controls must I use for identification codes and passwords? If you use electronic signatures based upon use of identification codes in combination with passwords, you must employ controls to ensure their...
Toward remote sensing with broadband terahertz waves
NASA Astrophysics Data System (ADS)
Clough, Benjamin W.
Terahertz electromagnetic waves, defined as the frequency region between 0.1 and 10 terahertz on the electromagnetic spectrum, have demonstrated remarkable usefulness for imaging and chemical identification with the ability to penetrate many optically opaque barriers. Photon energies at these frequencies are relatively small (meV), which means the radiation is non-ionizing and therefore considered biologically innocuous. With the growing list of applications and demand for terahertz technology, there is a need to develop innovative terahertz sources and detectors that can overcome existing limitations in power, bandwidth, and operating range. Although terahertz radiation has demonstrated unique and exceptional abilities, it has also presented several fundamental challenges. Most notably, the water vapor absorption of terahertz waves in air at habitable altitudes is greater than 100 dB/km. There is an immediate push to utilize the material and vapor identification abilities of terahertz radiation, while extending the effective distances over which the technology can be used. Remote terahertz detection, until recently, was thought to be impossible due to the high water content in the atmosphere, limited signal collection geometries, and solid state materials necessary for generation and detection. This dissertation focuses on laser air-photonics used for sensing short pulses of electromagnetic radiation. Through the ionization process, the very air that we breathe is capable of generating terahertz field strengths greater than 1 MV/cm, useful bandwidths over 100 terahertz, and highly directional emission patterns. Following ionization and plasma formation, the emitted plasma acoustics or fluorescence can be modulated by an external field to serve as omnidirectional, broadband, electromagnetic sensor. A deeper understanding of terahertz wave-plasma interaction is used to develop methods for retrieving coherent terahertz wave information that can be encoded into plasma acoustic and fluorescence wave emission; the ultimate goal aimed at overcoming fundamental limitations of the current terahertz technology. A synthesized bichromatic field-induced laser plasma is used to study effects of electron velocity redistribution inside the plasma filament, and a technique for obtaining a direct correlation between the terahertz field and the plasma acoustic or fluorescence emission is engineered. This dissertation presents significant advances in terahertz air photonics that help to close the "THz gap" once existing between electronic and optical frequencies, and the acoustic and fluorescence detection methodologies developed provide promising new avenues for extending the useful range of terahertz wave technology.
Systems and Methods for RFID-Enabled Pressure Sensing Apparatus
NASA Technical Reports Server (NTRS)
Kennedy, Timothy F. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Fink, Patrick W. (Inventor)
2017-01-01
Methods, apparatuses and systems for radio frequency identification (RFID)-enabled information collection are disclosed, including an enclosure, a collector coupled to the enclosure, an interrogator, a processor, and one or more RFID field sensors, each having an individual identification, disposed within the enclosure. In operation, the interrogator transmits an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure. The electromagnetic field is affected by one or more influences. RFID sensors respond to the electromagnetic field by transmitting reflected signals containing the individual identifications of the responding RFID sensors to the interrogator. The interrogator receives the reflected signals, measures one or more returned signal strength indications ("RSSI") of the reflected signals and sends the RSSI measurements and identification of the responding RFID sensors to the processor to determine one or more facts about the influences. Other embodiments are also described.
Systems and Methods for RFID-Enabled Dispenser
NASA Technical Reports Server (NTRS)
Fink, Patrick W. (Inventor); Kennedy, Timothy F. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Byerly, Diane (Inventor)
2015-01-01
Methods, apparatuses and systems for radio frequency identification (RFID)-enabled information collection are disclosed, including an enclosure, a collector coupled to the enclosure, an interrogator, a processor, and one or more RFID field sensors, each having an individual identification, disposed within the enclosure. In operation, the interrogator transmits an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure. The electromagnetic field is affected by one or more influences. RFID sensors respond to the electromagnetic field by transmitting reflected signals containing the individual identifications of the responding RFID sensors to the interrogator. The interrogator receives the reflected signals, measures one or more returned signal strength indications ("RSSI") of the reflected signals and sends the RSSI measurements and identification of the responding RFID sensors to the processor to determine one or more facts about the influences. Other embodiments are also described.
Systems and Methods for RFID-Enabled Pressure Sensing Apparatus
NASA Technical Reports Server (NTRS)
Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Kennedy, Timothy F. (Inventor); Fink, Patrick W. (Inventor)
2016-01-01
Methods, apparatuses and systems for radio frequency identification (RFID)-enabled information collection are disclosed, including an enclosure, a collector coupled to the enclosure, an interrogator, a processor, and one or more RFID field sensors, each having an individual identification, disposed within the enclosure. In operation, the interrogator transmits an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure. The electromagnetic field is affected by one or more influences. RFID sensors respond to the electromagnetic field by transmitting reflected signals containing the individual identifications of the responding RFID sensors to the interrogator. The interrogator receives the reflected signals, measures one or more returned signal strength indications ("RSSI") of the reflected signals and sends the RSSI measurements and identification of the responding RFID sensors to the processor to determine one or more facts about the influences. Other embodiments are also described.
System and Method for RFID-Enabled Information Collection
NASA Technical Reports Server (NTRS)
Fink, Patrick W. (Inventor); Kennedy, Timothy F. (Inventor); Lin, Gregory Y. (Inventor); Ngo, Phong H. (Inventor); Byerly, Diane (Inventor)
2016-01-01
Methods, apparatuses and systems for radio frequency identification (RFID)-enabled information collection are disclosed, including an enclosure, a collector coupled to the enclosure, an interrogator, a processor, and one or more RFID field sensors, each having an individual identification, disposed within the enclosure. In operation, the interrogator transmits an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure. The electromagnetic field is affected by one or more influences. RFID sensors respond to the electromagnetic field by transmitting reflected signals containing the individual identifications of the responding RFID sensors to the interrogator. The interrogator receives the reflected signals, measures one or more returned signal strength indications ("RSSI") of the reflected signals and sends the RSSI measurements and identification of the responding RFID sensors to the processor to determine one or more facts about the influences. Other embodiments are also described.
DOT National Transportation Integrated Search
1993-01-01
ELECTRONIC TOLL COLLECTION OR ETC AND TRAFFIC MANAGEMENT OR ETTM, AUTOMATIC VEHICLE IDENTIFICATION OR AVI : ELECTRONIC TOLL COLLECTION AND TRAFFIC MANAGEMENT (ETTM) SYSTEMS ARE NOT A FUTURISTIC DREAM, THEY ARE OPERATING OR ARE BEING TESTED TODAY I...
32 CFR 2001.23 - Classification marking in the electronic environment.
Code of Federal Regulations, 2010 CFR
2010-07-01
... INFORMATION SECURITY OVERSIGHT OFFICE, NATIONAL ARCHIVES AND RECORDS ADMINISTRATION CLASSIFIED NATIONAL SECURITY INFORMATION Identification and Markings § 2001.23 Classification marking in the electronic environment. (a) General. Classified national security information in the electronic environment shall be: (1...
32 CFR 2001.23 - Classification marking in the electronic environment.
Code of Federal Regulations, 2012 CFR
2012-07-01
... INFORMATION SECURITY OVERSIGHT OFFICE, NATIONAL ARCHIVES AND RECORDS ADMINISTRATION CLASSIFIED NATIONAL SECURITY INFORMATION Identification and Markings § 2001.23 Classification marking in the electronic environment. (a) General. Classified national security information in the electronic environment shall be: (1...
32 CFR 2001.23 - Classification marking in the electronic environment.
Code of Federal Regulations, 2013 CFR
2013-07-01
... INFORMATION SECURITY OVERSIGHT OFFICE, NATIONAL ARCHIVES AND RECORDS ADMINISTRATION CLASSIFIED NATIONAL SECURITY INFORMATION Identification and Markings § 2001.23 Classification marking in the electronic environment. (a) General. Classified national security information in the electronic environment shall be: (1...
32 CFR 2001.23 - Classification marking in the electronic environment.
Code of Federal Regulations, 2014 CFR
2014-07-01
... INFORMATION SECURITY OVERSIGHT OFFICE, NATIONAL ARCHIVES AND RECORDS ADMINISTRATION CLASSIFIED NATIONAL SECURITY INFORMATION Identification and Markings § 2001.23 Classification marking in the electronic environment. (a) General. Classified national security information in the electronic environment shall be: (1...
32 CFR 2001.23 - Classification marking in the electronic environment.
Code of Federal Regulations, 2011 CFR
2011-07-01
... INFORMATION SECURITY OVERSIGHT OFFICE, NATIONAL ARCHIVES AND RECORDS ADMINISTRATION CLASSIFIED NATIONAL SECURITY INFORMATION Identification and Markings § 2001.23 Classification marking in the electronic environment. (a) General. Classified national security information in the electronic environment shall be: (1...
Caja, G; Díaz-Medina, E; Salama, A A K; Salama, O A E; El-Shafie, M H; El-Metwaly, H A; Ayadi, M; Aljumaah, R S; Alshaikh, M A; Yahyahoui, M H; Seddik, M M; Hammadi, M; Khorchani, T; Amann, O; Cabrera, S
2016-08-01
The camel industry uses traditional (i.e., iron brands and ear tags) and modern (i.e., microchips) identification (ID) systems without having performance results of reference. Previously iron-branded ( = 45; 1 yr) and microchipped ( = 59; 7 yr) camels showed problems of healing (8.6% of brands) and reading (only 42.9% of brands and 69.5% of microchips were readable), which made their use inadvisable. With the aim of proposing suitable ID systems for different farming conditions, an on-field study was performed using a total of 528 dromedaries at 4 different locations (Egypt, = 83; Spain, = 304; Saudi Arabia, = 90; and Tunisia, = 51). The ID devices tested were visual (button ear tags, 28.5 mm diameter, = 178; double flag ear tags, 50 by 15 mm, = 83; both made of polyurethane) and electronic (ear tags, = 90, and rumen boluses, = 555). Electronic ear tags were polyurethane-loop type (75 by 9 mm) with a container in which a 22-mm transponder of full-duplex technology was lodged. Electronic boluses of 7 types, varying in dimensions (50 to 76 mm length, 11 to 21 mm width, and 12.7 to 82.1 g weight) and specific gravity (SG; 1.49 to 3.86) and each of them containing a 31-mm transponder of half-duplex technology, were all administered to the dromedaries at the beginning of the study. When a low-SG bolus was lost, a high-SG bolus was readministered. Readability rates of each ID system were evaluated during 1 to 3 yr, according to device and location, and yearly values were estimated for comparison. On a yearly basis, visual ear tag readability was not fully satisfactory; it was lower for rectangular ear tags (66.3%) than for button ear tags (80.9%). Yearly readability of electronic ear tags was 93.7%. Bolus readability dramatically varied according to their SG; the SG < 2.0 boluses were fully lost after 8 mo. In contrast, the SG > 3.0 boluses were efficiently retained (99.6 to 100%) at all locations. In conclusion, according to the expected long lifespan of camels, low ID performances were observed for iron brands, injectable microchips, and ear tags (visual and electronic), making their use inadvisable as unique ID systems in camels. The high readability of dense electronic boluses recommended their use as a permanent ID device of reference in camels.
Design and Status of the Mu2e Crystal Calorimeter
DOE Office of Scientific and Technical Information (OSTI.GOV)
Atanov, N.; et al.
2018-01-08
The Mu2e experiment at Fermilab searches for the charged-lepton flavour violating (CLFV) conversion of a negative muon into an electron in the field of an aluminum nucleus, with a distinctive signature of a mono-energetic electron of energy slightly below the muon rest mass (104.967 MeV). The Mu2e goal is to improve by four orders of magnitude the search sensitivity with respect to the previous experiments. Any observation of a CLFV signal will be a clear indication of new physics. The Mu2e detector is composed of a tracker, an electro- magnetic calorimeter and an external veto for cosmic rays surrounding themore » solenoid. The calorimeter plays an important role in providing particle identification capabilities, a fast online trigger filter, a seed for track reconstruction while working in vacuum, in the presence of 1 T axial magnetic field and in an harsh radiation environment. The calorimeter requirements are to provide a large acceptance for 100 MeV electrons and reach at these energies: (a) a time resolution better than 0.5 ns; (b) an energy resolution < 10% and (c) a position resolution of 1 cm. The calorimeter design consists of two disks, each one made of 674 undoped CsI crystals read by two large area arrays of UV-extended SiPMs. We report here the construction and test of the Module-0 prototype. The Module-0 has been exposed to an electron beam in the energy range around 100 MeV at the Beam Test Facility in Frascati. Preliminary results of timing and energy resolution at normal incidence are shown. A discussion of the technical aspects of the calorimeter engineering is also reported in this paper.« less
Nongyrotropic Electrons in Guide Field Reconnection
NASA Technical Reports Server (NTRS)
Wendel, D. E.; Hesse, M.; Bessho, N.; Adrian, M. L.; Kuznetsova, M.
2016-01-01
We apply a scalar measure of nongyrotropy to the electron pressure tensor in a 2D particle-in-cell simulation of guide field reconnection and assess the corresponding electron distributions and the forces that account for the nongyrotropy. The scalar measure reveals that the nongyrotropy lies in bands that straddle the electron diffusion region and the separatrices, in the same regions where there are parallel electric fields. Analysis of electron distributions and fields shows that the nongyrotropy along the inflow and outflow separatrices emerges as a result of multiple populations of electrons influenced differently by large and small-scale parallel electric fields and by gradients in the electric field. The relevant parallel electric fields include large-scale potential ramps emanating from the x-line and sub-ion inertial scale bipolar electron holes. Gradients in the perpendicular electric field modify electrons differently depending on their phase, thus producing nongyrotropy. Magnetic flux violation occurs along portions of the separatrices that coincide with the parallel electric fields. An inductive electric field in the electron EB drift frame thus develops, which has the effect of enhancing nongyrotropies already produced by other mechanisms and under certain conditions producing their own nongyrotropy. Particle tracing of electrons from nongyrotropic populations along the inflows and outflows shows that the striated structure of nongyrotropy corresponds to electrons arriving from different source regions. We also show that the relevant parallel electric fields receive important contributions not only from the nongyrotropic portion of the electron pressure tensor but from electron spatial and temporal inertial terms as well.
Gunshot identification system by integration of open source consumer electronics
NASA Astrophysics Data System (ADS)
López R., Juan Manuel; Marulanda B., Jose Ignacio
2014-05-01
This work presents a prototype of low-cost gunshots identification system that uses consumer electronics in order to ensure the existence of gunshots and then classify it according to a previously established database. The implementation of this tool in the urban areas is to set records that support the forensics, hence improving law enforcement also on developing countries. An analysis of its effectiveness is presented in comparison with theoretical results obtained with numerical simulations.
NASA Astrophysics Data System (ADS)
Abdellatif, Dehni; Mourad, Lounis
2017-07-01
Soil salinity is a complex problem that affects groundwater aquifers and agricultural lands in the semiarid regions. Remote sensing and spectroscopy database systems provide accuracy for salinity autodetection and dynamical delineation. Salinity detection techniques using polychromatic wavebands by field geocomputation and experimental data are time consuming and expensive. This paper presents an automated spectral detection and identification of salt minerals using a monochromatic waveband concept from multispectral bands-Landsat 8 Operational Land Imager (OLI) and Thermal InfraRed Sensor (TIRS) and spectroscopy United States Geological Survey database. For detecting mineral salts related to electrolytes, such as electronical and vibrational transitions, an integrated approach of salinity detection related to the optical monochromatic concept has been addressed. The purpose of this paper is to discriminate waveband intrinsic spectral similarity using the Beer-Lambert and Van 't Hoff laws for spectral curve extraction such as transmittance, reflectance, absorbance, land surface temperature, molar concentration, and osmotic pressure. These parameters are primordial for hydrodynamic salinity modeling and continuity identification using chemical and physical approaches. The established regression fitted models have been addressed for salt spectroscopy validation for suitable calibration and validation. Furthermore, our analytical tool is conducted for better decision interface using spectral salinity detection and identification in the Oran watershed, Algeria.
Colloidal synthesis of silicon nanoparticles in molten salts.
Shavel, A; Guerrini, L; Alvarez-Puebla, R A
2017-06-22
Silicon nanoparticles are unique materials with applications in a variety of fields, from electronics to catalysis and biomedical uses. Despite technological advancements in nanofabrication, the development of a simple and inexpensive route for the synthesis of homogeneous silicon nanoparticles remains highly challenging. Herein, we describe a new, simple and inexpensive colloidal synthetic method for the preparation, under normal pressure and mild temperature conditions, of relatively homogeneous spherical silicon nanoparticles of either ca. 4 or 6 nm diameter. The key features of this method are the selection of a eutectic salt mixture as a solvent, the identification of appropriate silicon alkoxide precursors, and the unconventional use of alkali earth metals as shape-controlling agents.
Interstellar molecules and dense clouds.
NASA Technical Reports Server (NTRS)
Rank, D. M.; Townes, C. H.; Welch, W. J.
1971-01-01
Current knowledge of the interstellar medium is discussed on the basis of recent published studies. The subjects considered include optical identification of interstellar molecules, radio molecular lines, interstellar clouds, isotopic abundances, formation and disappearance of interstellar molecules, and interstellar probing techniques. Diagrams are plotted for the distribution of galactic sources exhibiting molecular lines, for hydrogen molecule, hydrogen atom and electron abundances due to ionization, for the densities, velocities and temperature of NH3 in the direction of Sagitarius B2, for the lower rotational energy levels of H2CO, and for temporal spectral variations in masing H2O clouds of the radio source W49. Future applications of the maser and of molecular microscopy in this field are visualized.
Use of Kelvin probe force microscopy for identification of CVD grown graphene flakes on copper foil
NASA Astrophysics Data System (ADS)
Kumar, Rakesh; Mehta, B. R.; Kanjilal, D.
2017-05-01
Graphene flakes have been grown by chemical vapour deposition (CVD) method on Cu foils. The obtained graphene flakes have been characterized by optical microscopy, field emission scanning electron microscopy, Kelvin probe force microscopy (KPFM) and Raman spectroscopy. The graphene flakes grown on Cu foil comprise mainly single layer graphene and confirm that the nucleation for graphene growth starts very quickly. Moreover, KPFM has been found to be a valuable technique to differentiate between covered and uncovered portion of Cu foil by graphene flakes deposited for shorter duration. The results show that KPFM can be a very useful technique in understanding the mechanism of graphene growth.
Amorphous silicon radiation detectors
Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.
1992-01-01
Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.
Amorphous silicon radiation detectors
Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.
1992-11-17
Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.
Cynthia D. Huebner; Cassandra Olson; Heather C. Smith; Heather C. Smith
2005-01-01
There are many field guides available about invasive plants and their identification. The purpose of this particular field guide is to give a scientific synthesis of what is known about the behavior of such species in managed, disturbed, and pristine forested systems in addition to key information for accurate identification.
Two-stage Electron Acceleration by 3D Collisionless Guide-field Magnetic Reconnection
NASA Astrophysics Data System (ADS)
Buechner, J.; Munoz, P.
2017-12-01
We discuss a two-stage process of electron acceleration near X-lines of 3D collisionless guide-field magnetic reconnection. Non-relativistic electrons are first pre-accelerated by magnetic-field-aligned (parallel) electric fields. At the nonlinear stage of 3D guide-field magnetic reconnection electric and magnetic fields become filamentary structured due to streaming instabilities. This causes an additional curvature-driven electron acceleration in the guide-field direction. The resulting spectrum of the accelerated electrons follows a power law.
NASA Technical Reports Server (NTRS)
Min, Q.-L.; Lummerzheim, D.; Rees, M. H.; Stamnes, K.
1993-01-01
The consequences of electric field acceleration and an inhomogeneous magnetic field on auroral electron energy distributions in the topside ionosphere are investigated. The one-dimensional, steady state electron transport equation includes elastic and inelastic collisions, an inhomogeneous magnetic field, and a field-aligned electric field. The case of a self-consistent polarization electric field is considered first. The self-consistent field is derived by solving the continuity equation for all ions of importance, including diffusion of O(+) and H(+), and the electron and ion energy equations to derive the electron and ion temperatures. The system of coupled electron transport, continuity, and energy equations is solved numerically. Recognizing observations of parallel electric fields of larger magnitude than the baseline case of the polarization field, the effect of two model fields on the electron distribution function is investigated. In one case the field is increased from the polarization field magnitude at 300 km to a maximum at the upper boundary of 800 km, and in another case a uniform field is added to the polarization field. Substantial perturbations of the low energy portion of the electron flux are produced: an upward directed electric field accelerates the downward directed flux of low-energy secondary electrons and decelerates the upward directed component. Above about 400 km the inhomogeneous magnetic field produces anisotropies in the angular distribution of the electron flux. The effects of the perturbed energy distributions on auroral spectral emission features are noted.
NASA Technical Reports Server (NTRS)
Min, Q.-L.; Lummerzheim, D.; Rees, M. H.; Stamnes, K.
1993-01-01
The consequences of electric field acceleration and an inhomogencous magnetic field on auroral electron energy distributions in the topside ionosphere are investigated. The one- dimensional, steady state electron transport equation includes elastic and inelastic collisions, an inhomogencous magnetic field, and a field-aligned electric field. The case of a self-consistent polarization electric field is considered first. The self-consistent field is derived by solving the continuity equation for all ions of importance, including diffusion of 0(+) and H(+), and the electron and ion energy equations to derive the electron and ion temperatures. The system of coupled electron transport, continuity, and energy equations is solved numerically. Recognizing observations of parallel electric fields of larger magnitude than the baseline case of the polarization field, the effect of two model fields on the electron distribution function in investigated. In one case the field is increased from the polarization field magnitude at 300 km to a maximum at the upper boundary of 800 km, and in another case a uniform field is added to the polarization field. Substantial perturbations of the low energy portion of the electron flux are produced: an upward directed electric field accelerates the downward directed flux of low-energy secondary electrons and decelerates the upward directed component. Above about 400 km the inhomogencous magnetic field produces anisotropies in the angular distribution of the electron flux. The effects of the perturbed energy distributions on auroral spectral emission features are noted.
Laser-driven electron acceleration in a plasma channel with an additional electric field
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cheng, Li-Hong; Xue, Ju-Kui, E-mail: xuejk@nwnu.edu.cn; Liu, Jie, E-mail: liu-jie@iapcm.ac.cn
2016-05-15
We examine the electron acceleration in a two-dimensional plasma channel under the action of a laser field and an additional static electric field. We propose to design an appropriate additional electric field (its direction and location), in order to launch the electron onto an energetic trajectory. We find that the electron acceleration strongly depends on the coupled effects of the laser polarization, the direction, and location of the additional electric field. The additional electric field affects the electron dynamics by changing the dephasing rate. Particularly, a suitably designed additional electric field leads to a considerable energy gain from the lasermore » pulse after the interaction with the additional electric field. The electron energy gain from the laser with the additional electric field can be much higher than that without the additional electric field. This engineering provides a possible means for producing high energetic electrons.« less
Metal oxide based multisensor array and portable database for field analysis of antioxidants
Sharpe, Erica; Bradley, Ryan; Frasco, Thalia; Jayathilaka, Dilhani; Marsh, Amanda; Andreescu, Silvana
2014-01-01
We report a novel chemical sensing array based on metal oxide nanoparticles as a portable and inexpensive paper-based colorimetric method for polyphenol detection and field characterization of antioxidant containing samples. Multiple metal oxide nanoparticles with various polyphenol binding properties were used as active sensing materials to develop the sensor array and establish a database of polyphenol standards that include epigallocatechin gallate, gallic acid, resveratrol, and Trolox among others. Unique charge-transfer complexes are formed between each polyphenol and each metal oxide on the surface of individual sensors in the array, creating distinct optically detectable signals which have been quantified and logged into a reference database for polyphenol identification. The field-portable Pantone/X-Rite© CapSure® color reader was used to create this database and to facilitate rapid colorimetric analysis. The use of multiple metal-oxide sensors allows for cross-validation of results and increases accuracy of analysis. The database has enabled successful identification and quantification of antioxidant constituents within real botanical extractions including green tea. Formation of charge-transfer complexes is also correlated with antioxidant activity exhibiting electron transfer capabilities of each polyphenol. The antioxidant activity of each sample was calculated and validated against the oxygen radical absorbance capacity (ORAC) assay showing good comparability. The results indicate that this method can be successfully used for a more comprehensive analysis of antioxidant containing samples as compared to conventional methods. This technology can greatly simplify investigations into plant phenolics and make possible the on-site determination of antioxidant composition and activity in remote locations. PMID:24610993
NASA Astrophysics Data System (ADS)
Bessho, N.; Chen, L. J.; Hesse, M.; Wang, S.
2017-12-01
In asymmetric reconnection with a guide field in the Earth's magnetopause, electron motion in the electron diffusion region (EDR) is largely affected by the guide field, the Hall electric field, and the reconnection electric field. The electron motion in the EDR is neither simple gyration around the guide field nor simple meandering motion across the current sheet. The combined meandering motion and gyration has essential effects on particle acceleration by the in-plane Hall electric field (existing only in the magnetospheric side) and the out-of-plane reconnection electric field. We analyze electron motion and crescent-shaped electron distribution functions in the EDR in asymmetric guide field reconnection, and perform 2-D particle-in-cell (PIC) simulations to elucidate the effect of reconnection electric field on electron distribution functions. Recently, we have analytically expressed the acceleration effect due to the reconnection electric field on electron crescent distribution functions in asymmetric reconnection without a guide field (Bessho et al., Phys. Plasmas, 24, 072903, 2017). We extend the theory to asymmetric guide field reconnection, and predict the crescent bulge in distribution functions. Assuming 1D approximation of field variations in the EDR, we derive the time period of oscillatory electron motion (meandering + gyration) in the EDR. The time period is expressed as a hybrid of the meandering period and the gyro period. Due to the guide field, electrons not only oscillate along crescent-shaped trajectories in the velocity plane perpendicular to the antiparallel magnetic fields, but also move along parabolic trajectories in the velocity plane coplanar with magnetic field. The trajectory in the velocity space gradually shifts to the acceleration direction by the reconnection electric field as multiple bounces continue. Due to the guide field, electron distributions for meandering particles are bounded by two paraboloids (or hyperboloids) in the velocity space. We compare theory and PIC simulation results of the velocity shift of crescent distribution functions based on the derived time period of bounce motion in a guide field. Theoretical predictions are applied to electron distributions observed by MMS in magnetopause reconnection to estimate the reconnection electric field.
Code of Federal Regulations, 2014 CFR
2014-04-01
... trading; and (iv) Identification of each account to which fills are allocated. (3) Electronic analysis capability. A swap execution facility's audit trail program shall include electronic analysis capability with respect to all audit trail data in the transaction history database. Such electronic analysis capability...
Analysis of magnetically immersed electron guns with non-adiabatic fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pikin, Alexander; Alessi, James G.; Beebe, Edward N.
Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams withmore » high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. In conclusion, the tests results of non-adiabatic electron gun with modified magnetic field are presented.« less
Analysis of magnetically immersed electron guns with non-adiabatic fields
Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; ...
2016-11-08
Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams withmore » high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. In conclusion, the tests results of non-adiabatic electron gun with modified magnetic field are presented.« less
Analysis of magnetically immersed electron guns with non-adiabatic fields.
Pikin, Alexander; Alessi, James G; Beebe, Edward N; Raparia, Deepak; Ritter, John
2016-11-01
Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams with high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map, different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. The tests' results of a non-adiabatic electron gun with modified magnetic field are presented.
Vanin, Anatoly F
2018-06-01
The overview demonstrates how the use of only one physico-chemical approach, viz., the electron paramagnetic resonance method, allowed detection and identification of dinitrosyl iron complexes with thiol-containing ligands in various animal and bacterial cells. These complexes are formed in biological objects in the paramagnetic (electron paramagnetic resonance-active) mononuclear and diamagnetic (electron paramagnetic resonance-silent) binuclear forms and control the activity of nitrogen monoxide, one of the most universal regulators of metabolic processes in the organism. The analysis of electronic and spatial structures of dinitrosyl iron complex sheds additional light on the mechanism whereby dinitrosyl iron complex with thiol-containing ligands function in human and animal cells as donors of nitrogen monoxide and its ionized form, viz., nitrosonium ions (NO + ).
Electronic Properties of Synthetic Shrimp Pathogens-derived DNA Schottky Diodes.
Rizan, Nastaran; Yew, Chan Yen; Niknam, Maryam Rajabpour; Krishnasamy, Jegenathan; Bhassu, Subha; Hong, Goh Zee; Devadas, Sridevi; Din, Mohamed Shariff Mohd; Tajuddin, Hairul Anuar; Othman, Rofina Yasmin; Phang, Siew Moi; Iwamoto, Mitsumasa; Periasamy, Vengadesh
2018-01-17
The exciting discovery of the semiconducting-like properties of deoxyribonucleic acid (DNA) and its potential applications in molecular genetics and diagnostics in recent times has resulted in a paradigm shift in biophysics research. Recent studies in our laboratory provide a platform towards detecting charge transfer mechanism and understanding the electronic properties of DNA based on the sequence-specific electronic response, which can be applied as an alternative to identify or detect DNA. In this study, we demonstrate a novel method for identification of DNA from different shrimp viruses and bacteria using electronic properties of DNA obtained from both negative and positive bias regions in current-voltage (I-V) profiles. Characteristic electronic properties were calculated and used for quantification and further understanding in the identification process. Aquaculture in shrimp industry is a fast-growing food sector throughout the world. However, shrimp culture in many Asian countries faced a huge economic loss due to disease outbreaks. Scientists have been using specific established methods for detecting shrimp infection, but those methods do have their significant drawbacks due to many inherent factors. As such, we believe that this simple, rapid, sensitive and cost-effective tool can be used for detection and identification of DNA from different shrimp viruses and bacteria.
Accurate identification of layer number for few-layer WS2 and WSe2 via spectroscopic study.
Li, Yuanzheng; Li, Xinshu; Yu, Tong; Yang, Guochun; Chen, Heyu; Zhang, Cen; Feng, Qiushi; Ma, Jiangang; Liu, Weizhen; Xu, Haiyang; Liu, Yichun; Liu, Xinfeng
2018-03-23
Transition metal dichalcogenides (TMDs) with a typical layered structure are highly sensitive to their layer number in optical and electronic properties. Seeking a simple and effective method for layer number identification is very important to low-dimensional TMD samples. Herein, a rapid and accurate layer number identification of few-layer WS 2 and WSe 2 is proposed via locking their photoluminescence (PL) peak-positions. As the layer number of WS 2 /WSe 2 increases, it is found that indirect transition emission is more thickness-sensitive than direct transition emission, and the PL peak-position differences between the indirect and direct transitions can be regarded as fingerprints to identify their layer number. Theoretical calculation confirms that the notable thickness-sensitivity of indirect transition derives from the variations of electron density of states of W atom d-orbitals and chalcogen atom p-orbitals. Besides, the PL peak-position differences between the indirect and direct transitions are almost independent of different insulating substrates. This work not only proposes a new method for layer number identification via PL studies, but also provides a valuable insight into the thickness-dependent optical and electronic properties of W-based TMDs.
Bird on Your Smartphone: How to make identification faster?
NASA Astrophysics Data System (ADS)
Hidayat, T.; Kurniawan, I. S.; Tapilow, F. S.
2018-01-01
Identification skills of students are needed in the field activities of animal ecology course. Good identification skills will help students to understand the traits, determine differences and similarities in order to naming of birds’ species. This study aims to describe the identification skill of students by using smart phone applications designed in such a way as a support in the field activities. Research method used was quasi experiment involving 60 students which were divided into two groups, one group that use smartphone applications (SA) and other group using a guidebook (GB). This study was carried out in the classroom and outside (the field). Instruments used in this research included tests and questionnaire. The identification skills were measured by tests, indicated by an average score (AS). The results showed that the identification skills of SA students were higher (AS = 3.12) than those of GB one (AS = 2.91). These results are in accordance with response of students. The most of students (90.08%) mentioned that the use of smart phone applications in identifying birds is helpful, more effective and convenience to make identification faster. For further implementation, however, performance of the smartphone used here need to be enhanced to improve the identification skills of students and for wider use.
Antireduction: an ancient strategy fit for future.
Becker, Petra Maria
2016-08-01
While antioxidants are on everyone's lips, antireductants are their much less-known counterparts. Following an antioxidant's definition, an antireductant prevents the chemical reduction of another compound by undergoing reduction itself. Antireductants have been traced back as far as the origin of life, which they facilitated by removal of atmospheric dihydrogen, H2 Moreover, as electron acceptors, antireductants equipped the first metabolic pathways, enabling lithoautotrophic microbial growth. When the Earth's atmosphere became more oxidizing, certain antireductants revealed their Janus-face by acting as antioxidants. Both capacities, united in one compound, were detected in primary as well as plant secondary metabolites. Substantiated by product identification, such antireductants comprise antiradicals (e.g. carotenoids) up to diminishers of ruminal methane emission (e.g. fumarate, catechin or resveratrol). Beyond these Janus-faced, multifunctional compounds, the spectrum of antireductants extends to pure electron-attractors (e.g. atmospheric triplet oxygen, O2, for plant root and gut protection). Current and prospective fields of antireductant application range from health promotion over industrial production to environmental sustainability. © 2016 The Author(s).
Antireduction: an ancient strategy fit for future
Becker, Petra Maria
2016-01-01
While antioxidants are on everyone's lips, antireductants are their much less-known counterparts. Following an antioxidant's definition, an antireductant prevents the chemical reduction of another compound by undergoing reduction itself. Antireductants have been traced back as far as the origin of life, which they facilitated by removal of atmospheric dihydrogen, H2. Moreover, as electron acceptors, antireductants equipped the first metabolic pathways, enabling lithoautotrophic microbial growth. When the Earth's atmosphere became more oxidizing, certain antireductants revealed their Janus-face by acting as antioxidants. Both capacities, united in one compound, were detected in primary as well as plant secondary metabolites. Substantiated by product identification, such antireductants comprise antiradicals (e.g. carotenoids) up to diminishers of ruminal methane emission (e.g. fumarate, catechin or resveratrol). Beyond these Janus-faced, multifunctional compounds, the spectrum of antireductants extends to pure electron-attractors (e.g. atmospheric triplet oxygen, O2, for plant root and gut protection). Current and prospective fields of antireductant application range from health promotion over industrial production to environmental sustainability. PMID:27274089
Nanoscale infrared spectroscopy as a non-destructive probe of extraterrestrial samples.
Dominguez, Gerardo; Mcleod, A S; Gainsforth, Zack; Kelly, P; Bechtel, Hans A; Keilmann, Fritz; Westphal, Andrew; Thiemens, Mark; Basov, D N
2014-12-09
Advances in the spatial resolution of modern analytical techniques have tremendously augmented the scientific insight gained from the analysis of natural samples. Yet, while techniques for the elemental and structural characterization of samples have achieved sub-nanometre spatial resolution, infrared spectral mapping of geochemical samples at vibrational 'fingerprint' wavelengths has remained restricted to spatial scales >10 μm. Nevertheless, infrared spectroscopy remains an invaluable contactless probe of chemical structure, details of which offer clues to the formation history of minerals. Here we report on the successful implementation of infrared near-field imaging, spectroscopy and analysis techniques capable of sub-micron scale mineral identification within natural samples, including a chondrule from the Murchison meteorite and a cometary dust grain (Iris) from NASA's Stardust mission. Complementary to scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy probes, this work evidences a similarity between chondritic and cometary materials, and inaugurates a new era of infrared nano-spectroscopy applied to small and invaluable extraterrestrial samples.
Stewart, S C; Rapnicki, P; Lewis, J R; Perala, M
2007-09-01
The ability of a commercially available panel reader system to read International Standards Organization-compliant electronic identification devices under commercial dairy conditions was examined. Full duplex (FDX-B) and half-duplex (HDX) low frequency radio-frequency identification external ear tags were utilized. The study involved 498 Holstein cows in the final 6 wk of gestation. There were 516 total electronic identification devices (n = 334 HDX and n = 182 FDX-B). Eighteen FDX-B were replaced with HDX during the study due to repeated detection failure. There were 6,679 HDX and 3,401 FDX-B device detection attempts. There were 220 (2.2%) unsuccessful and 9,860 (97.8%) successful identification detection attempts. There were 9 unsuccessful detection attempts for HDX (6,670/6,679 = 99.9% successful detection attempts) and 211 unsuccessful detection attempts for FDX-B (3,190/3,401 = 93.8% successful detection attempts). These results demonstrate that this panel system can achieve high detection rates of HDX devices and meet the needs of the most demanding management applications. The FDX-B detection rate was not sufficient for the most demanding applications, requiring a high degree of detection by panel readers. The lower FDX-B rate may not be inherent in the device technology itself, but could be due to other factors, including the particular panel reader utilized or the tuning of the panel reader.
Rios, Pedro; Stuart, Julie Ann; Grant, Ed
2003-12-01
Annual plastic flows through the business and consumer electronics manufacturing supply chain include nearly 3 billion lb of high-value engineering plastics derived from petroleum. The recovery of resource value from this stream presents critical challenges in areas of materials identification and recycling process design that demand new green engineering technologies applied together with life cycle assessment and ecological supply chain analysis to create viable plastics-to-plastics supply cycles. The sustainable recovery of potentially high-value engineering plastics streams requires that recyclers either avoid mixing plastic parts or purify later by separating smaller plastic pieces created in volume reduction (shredding) steps. Identification and separation constitute significant barriers in the plastics-to-plastics recycling value proposition. In the present work, we develop a model that accepts randomly arriving electronic products to study scenarios by which a recycler might identify and separate high-value engineering plastics as well as metals. Using discrete eventsimulation,we compare current mixed plastics recovery with spectrochemical plastic resin identification and subsequent sorting. Our results show that limited disassembly with whole-part identification can produce substantial yields in separated streams of recovered engineering thermoplastics. We find that disassembly with identification does not constitute a bottleneck, but rather, with relatively few workers, can be configured to pull the process and thus decrease maximum staging space requirements.
Electron beam assisted field evaporation of insulating nanowires/tubes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Blanchard, N. P., E-mail: nicholas.blanchard@univ-lyon1.fr; Niguès, A.; Choueib, M.
2015-05-11
We demonstrate field evaporation of insulating materials, specifically BN nanotubes and undoped Si nanowires, assisted by a convergent electron beam. Electron irradiation leads to positive charging at the nano-object's apex and to an important increase of the local electric field thus inducing field evaporation. Experiments performed both in a transmission electron microscope and in a scanning electron microscope are presented. This technique permits the selective evaporation of individual nanowires in complex materials. Electron assisted field evaporation could be an interesting alternative or complementary to laser induced field desorption used in atom probe tomography of insulating materials.
Trirotron: triode rotating beam radio frequency amplifier
Lebacqz, Jean V.
1980-01-01
High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rotating field to thereby produce a high-power output at the frequency of the rotating field.
Vassilakopoulou, Polyxeni; Tsagkas, Vassilis; Marmaras, Nicolas
2012-01-01
This paper investigates workarounds occurring while pharmacists use an electronic prescription (ePrescription) application. ePrescription enables physicians to send prescriptions electronically to pharmacies and was recently introduced in Greece as a solution for controlling the ever-increasing medication costs and improving patient safety. The research was carried out in two phases: (i) review of the relevant documentation, (ii) fieldwork (field observations and semi-structured interviews with the pharmacists) in three pharmacies. The workarounds identified fall into five categories and namely: (a) bypass of ePrescription application (i.e. ePrescription application is not used at all), (b) temporal nonconformity in the use of ePrescription application (i.e. usage of the application, but not at the formally specified time), (c) catachresis of ePrescription application (i.e. usage of the application, but not according to the intended way), (d) ePrescription application substitution by another electronic application, and (e) delegation of ePrescription application usage to non-authorized users. The outcome of the research can be used for the improvement of multiple work system elements such as the tools, the procedures, the organisational arrangements and the policies.
Characterization of Multianode Photomultiplier Tubes for a Cherenkov Detector
NASA Astrophysics Data System (ADS)
Benninghoff, Morgen; Turisini, Matteo; Kim, Andrey; Benmokhtar, Fatiha; Kubarovsky, Valery; Duquesne University Collaboration; Jefferson Lab Collaboration
2017-09-01
In the Fall of 2017, Jefferson Lab's CLAS12 (CEBAF Large Acceptance Spectrometer) detector is expecting the addition of a RICH (ring imaging Cherenkov) detector which will allow enhanced particle identification in the momentum range of 3 to 8 GeV/c. RICH detectors measure the velocity of charged particles through the detection of produced Cherenkov radiation and the reconstruction of the angle of emission. The emitted Cherenkov photons are detected by a triangular-shaped grid of 391 multianode photomultiplier tubes (MAPMTs) made by Hamamatsu. The custom readout electronics consist of MAROC (multianode read out chip) boards controlled by FPGA (Field Programmable Gate Array) boards, and adapters used to connect the MAROC boards and MAPMTs. The focus of this project is the characterization of the MAPMTs with the new front end electronics. To perform these tests, a black box setup with a picosecond diode laser was constructed with low and high voltage supplies. A highly automated procedure was developed to acquire data at different combinations of high voltage values, light intensities and readout electronics settings. Future work involves using the collected data in calibration procedures and analyzing that data to resolve the best location for each MAPMT. SULI, NSF.
Zhou, Qifan; Zhang, Hai; Lari, Zahra; Liu, Zhenbo; El-Sheimy, Naser
2016-10-21
Wearable electronic devices have experienced increasing development with the advances in the semiconductor industry and have received more attention during the last decades. This paper presents the development and implementation of a novel inertial sensor-based foot-mounted wearable electronic device for a brand new application: game playing. The main objective of the introduced system is to monitor and identify the human foot stepping direction in real time, and coordinate these motions to control the player operation in games. This proposed system extends the utilized field of currently available wearable devices and introduces a convenient and portable medium to perform exercise in a more compelling way in the near future. This paper provides an overview of the previously-developed system platforms, introduces the main idea behind this novel application, and describes the implemented human foot moving direction identification algorithm. Practical experiment results demonstrate that the proposed system is capable of recognizing five foot motions, jump, step left, step right, step forward, and step backward, and has achieved an over 97% accuracy performance for different users. The functionality of the system for real-time application has also been verified through the practical experiments.
Zhou, Qifan; Zhang, Hai; Lari, Zahra; Liu, Zhenbo; El-Sheimy, Naser
2016-01-01
Wearable electronic devices have experienced increasing development with the advances in the semiconductor industry and have received more attention during the last decades. This paper presents the development and implementation of a novel inertial sensor-based foot-mounted wearable electronic device for a brand new application: game playing. The main objective of the introduced system is to monitor and identify the human foot stepping direction in real time, and coordinate these motions to control the player operation in games. This proposed system extends the utilized field of currently available wearable devices and introduces a convenient and portable medium to perform exercise in a more compelling way in the near future. This paper provides an overview of the previously-developed system platforms, introduces the main idea behind this novel application, and describes the implemented human foot moving direction identification algorithm. Practical experiment results demonstrate that the proposed system is capable of recognizing five foot motions, jump, step left, step right, step forward, and step backward, and has achieved an over 97% accuracy performance for different users. The functionality of the system for real-time application has also been verified through the practical experiments. PMID:27775673
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhang, Bin; Chen, Yongjin; Han, Xiaodong, E-mail: wzhang0@mail.xjtu.edu.cn, E-mail: ema@jhu.edu, E-mail: xdhan@bjut.edu.cn
Disorder-induced electron localization and metal-insulator transitions (MITs) have been a very active research field starting from the seminal paper by Anderson half a century ago. However, pure Anderson insulators are very difficult to identify due to ubiquitous electron-correlation effects. Recently, an MIT has been observed in electrical transport measurements on the crystalline state of phase-change GeSbTe compounds, which appears to be exclusively disorder driven. Subsequent density functional theory simulations have identified vacancy disorder to localize electrons at the Fermi level. Here, we report a direct atomic scale chemical identification experiment on the rocksalt structure obtained upon crystallization of amorphous Ge{submore » 2}Sb{sub 2}Te{sub 5}. Our results confirm the two-sublattice structure resolving the distribution of chemical species and demonstrate the existence of atomic disorder on the Ge/Sb/vacancy sublattice. Moreover, we identify a gradual vacancy ordering process upon further annealing. These findings not only provide a structural underpinning of the observed Anderson localization but also have implications for the development of novel multi-level data storage within the crystalline phases.« less
Palmieri, Roberta; Bonifazi, Giuseppe; Serranti, Silvia
2014-11-01
This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further "sustainable" recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both "traditional" (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery. Copyright © 2014 Elsevier Ltd. All rights reserved.
A Michelson Interferometer for Electron Cyclotron Emission Measurements on EAST
NASA Astrophysics Data System (ADS)
Liu, Yong; Stefan, Schmuck; Zhao, Hailin; John, Fessey; Paul, Trimble; Liu, Xiang; Zhu, Zeying; Zang, Qing; Hu, Liqun
2016-12-01
A Michelson interferometer, on loan from EFDA-JET (Culham, United Kingdom) has recently been commissioned on the experimental advanced superconducting tokamak (EAST, ASIPP, Hefei, China). Following a successful in-situ absolute calibration the instrument is able to measure the electron cyclotron emission (ECE) spectrum, from 80 GHz to 350 GHz in extraordinary mode (X-mode) polarization, with high accuracy. This allows the independent determination of the electron temperature profile from observation of the second harmonic ECE and the possible identification of non-Maxwellian features by comparing higher harmonic emission with numerical simulations. The in-situ calibration results are presented together with the initial measured temperature profiles. These measurements are then discussed and compared with other independent temperature profile measurements. This paper also describes the main hardware features of the diagnostic and the associated commissioning test results. supported by National Natural Science Foundation of China (Nos. 11405211, 11275233), and the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB106002, 2015GB101000), and the RCUK Energy Programme (No. EP/I501045), partly supported by the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics (NSFC: No. 11261140328)
Atomic and electronic structures of BaHfO3-doped TFA-MOD-derived YBa2Cu3O7-δ thin films
NASA Astrophysics Data System (ADS)
Molina-Luna, Leopoldo; Duerrschnabel, Michael; Turner, Stuart; Erbe, Manuela; Martinez, Gerardo T.; Van Aert, Sandra; Holzapfel, Bernhard; Van Tendeloo, Gustaaf
2015-11-01
Tailoring the properties of oxide-based nanocomposites is of great importance for a wide range of materials relevant for energy technology. YBa2Cu3O7-δ (YBCO) superconducting thin films containing nanosized BaHfO3 (BHO) particles yield a significant improvement of the magnetic flux pinning properties and a reduced anisotropy of the critical current density. These films were prepared by chemical solution deposition (CSD) on (100) SrTiO3 (STO) substrates yielding critical current densities up to 3.6 MA cm-2 at 77 K and self-field. Transport in-field J c measurements demonstrated a high pinning force maximum of around 6 GN/m3 for a sample annealed at T = 760 °C that has a doping of 12 mol% of BHO. This sample was investigated by scanning transmission electron microscopy (STEM) in combination with electron energy-loss spectroscopy (EELS) yielding strain and spectral maps. Spherical BHO nanoparticles of 15 nm in size were found in the matrix, whereas the particles at the interface were flat. A 2 nm diffusion layer containing Ti was found at the YBCO (BHO)/STO interface. Local lattice deformation mapping at the atomic scale revealed crystal defects induced by the presence of both sorts of BHO nanoparticles, which can act as pinning centers for magnetic flux lines. Two types of local lattice defects were identified and imaged: (i) misfit edge dislocations and (ii) Ba-Cu-Cu-Ba stacking faults (Y-248 intergrowths). The local electronic structure and charge transfer were probed by high energy resolution monochromated electron energy-loss spectroscopy. This technique made it possible to distinguish superconducting from non-superconducting areas in nanocomposite samples with atomic resolution in real space, allowing the identification of local pinning sites on the order of the coherence length of YBCO (˜1.5 nm) and the determination of 0.25 nm dislocation cores.
Mander, Luke; Baker, Sarah J.; Belcher, Claire M.; Haselhorst, Derek S.; Rodriguez, Jacklyn; Thorn, Jessica L.; Tiwari, Shivangi; Urrego, Dunia H.; Wesseln, Cassandra J.; Punyasena, Surangi W.
2014-01-01
• Premise of the study: Humans frequently identify pollen grains at a taxonomic rank above species. Grass pollen is a classic case of this situation, which has led to the development of computational methods for identifying grass pollen species. This paper aims to provide context for these computational methods by quantifying the accuracy and consistency of human identification. • Methods: We measured the ability of nine human analysts to identify 12 species of grass pollen using scanning electron microscopy images. These are the same images that were used in computational identifications. We have measured the coverage, accuracy, and consistency of each analyst, and investigated their ability to recognize duplicate images. • Results: Coverage ranged from 87.5% to 100%. Mean identification accuracy ranged from 46.67% to 87.5%. The identification consistency of each analyst ranged from 32.5% to 87.5%, and each of the nine analysts produced considerably different identification schemes. The proportion of duplicate image pairs that were missed ranged from 6.25% to 58.33%. • Discussion: The identification errors made by each analyst, which result in a decline in accuracy and consistency, are likely related to psychological factors such as the limited capacity of human memory, fatigue and boredom, recency effects, and positivity bias. PMID:25202649
NASA Astrophysics Data System (ADS)
Lazio, T. Joseph; Shkolnik, Evgenya; Hallinan, Gregg
2017-05-01
The W. M. Keck Institute for Space Studies (KISS) sponsored the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study to review the state of knowledge of extrasolar planetary magnetic fields and the prospects for their detection.There were multiple motivations for this Study. Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. In turn, these internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these in objects' interiors. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind or an orbiting satellite, a planet's magnetic field can produce intense electron cyclotron masers in its magnetic polar regions. The most well known example of this process in the solar system is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior--all of which will be difficult to determine by other means--as well as improved understanding of the basic planetary dynamo process.We review the findings from the Study, including potential mission concepts that emerged and recent developments toward one of the mission concepts, a space-based radio wavelength array. There was an identification of that radio wavelength observations would likely be key to making significant progress in this field.We acknowledge ideas and advice from the participants in the "Planetary Magnetic Fields: Planetary Interiors and Habitability" study organized by the W. M. Keck Institute for Space Studies. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Nanowire electron scattering spectroscopy
NASA Technical Reports Server (NTRS)
Hunt, Brian D. (Inventor); Bronikowski, Michael (Inventor); Wong, Eric W. (Inventor); von Allmen, Paul (Inventor); Oyafuso, Fabiano A. (Inventor)
2009-01-01
Methods and devices for spectroscopic identification of molecules using nanoscale wires are disclosed. According to one of the methods, nanoscale wires are provided, electrons are injected into the nanoscale wire; and inelastic electron scattering is measured via excitation of low-lying vibrational energy levels of molecules bound to the nanoscale wire.
Methods and application of system identification in shock and vibration.
NASA Technical Reports Server (NTRS)
Collins, J. D.; Young, J. P.; Kiefling, L.
1972-01-01
A logical picture is presented of current useful system identification techniques in the shock and vibration field. A technology tree diagram is developed for the purpose of organizing and categorizing the widely varying approaches according to the fundamental nature of each. Specific examples of accomplished activity for each identification category are noted and discussed. To provide greater insight into the most current trends in the system identification field, a somewhat detailed description is presented of the essential features of a recently developed technique that is based on making the maximum use of all statistically known information about a system.
Sebei, P J; McCrindle, C M E; Green, E D; Turner, M L
2004-06-01
Lice have been described on goats in commercial farming systems in South Africa but not from flocks on communal grazing. During a longitudinal survey on the causes of goat kid mortality, conducted in Jericho district, North West Province, lice were collected from communally grazed indigenous goats. These lice were prepared for and viewed by scanning electron microscopy, and micro-morphological taxonomic details are described. Three species of lice were found in the study area and identified as Bovicola caprae, Bovicola limbatus and Linognathus africanus. Sucking and biting lice were found in ten of the 12 herds of goats examined. Lice were found on both mature goats and kids. Bovicola caprae and L. africanus were the most common biting and sucking lice respectively in all herds examined. Scanning electron microscopy revealed additional features which aided in the identification of the louse species. Photomicrographs were more accurate aids to identification than the line drawings in the literature and facilitated identification using dissecting microscope.
Nurjuliana, M; Che Man, Y B; Mat Hashim, D; Mohamed, A K S
2011-08-01
The volatile compounds of pork, other meats and meat products were studied using an electronic nose and gas chromatography mass spectrometer with headspace analyzer (GCMS-HS) for halal verification. The zNose™ was successfully employed for identification and differentiation of pork and pork sausages from beef, mutton and chicken meats and sausages which were achieved using a visual odor pattern called VaporPrint™, derived from the frequency of the surface acoustic wave (SAW) detector of the electronic nose. GCMS-HS was employed to separate and analyze the headspace gasses from samples into peaks corresponding to individual compounds for the purpose of identification. Principal component analysis (PCA) was applied for data interpretation. Analysis by PCA was able to cluster and discriminate pork from other types of meats and sausages. It was shown that PCA could provide a good separation of the samples with 67% of the total variance accounted by PC1. Copyright © 2011 Elsevier Ltd. All rights reserved.
Smith, Sandi W; Hitt, Rose; Park, Hee Sun; Walther, Joseph; Liang, Yuhua Jake; Hsieh, Gary
2016-01-01
The effort to increase Web organ donation registrations in Michigan by enhancing 2 types of university campaigns with social media strategies informed by social identity theory is the focus of this research. The two campaigns focused on either ingroup or rivalry outgroup social identification, and each was enhanced with individually focused social media in the first year of the campaign and with electronic word of mouth in Year 2 of the campaign. Results indicated that individually focused social media such as Facebook ads worked well in rivalry campaigns (in which registrations increased two times over baseline) but not in ingroup identification campaigns (in which registrations decreased significantly over baseline when ads were introduced in the first year of each type of campaign). Electronic word-of-mouth strategies worked well in both ingroup identification campaigns (in which registrations increased two times over baseline) and rivalry campaigns (in which registrations rose almost eight times over baseline, when strategies were introduced in the second year of each type of campaign).
A conservative, relativistic Fokker-Planck solver for runaway electrons
NASA Astrophysics Data System (ADS)
Chacon, Luis; Taitano, W.; Tang, X.; Guo, Z.; McDevitt, C.
2017-10-01
Relativistic runaway electrons develop when electric fields surpass a critical electric field, Ec =ED
Szpila, Krzysztof; Villet, Martin H
2011-07-01
Scanning electron microscopy images of the first instars of Calliphora croceipalpis Jaennicke, 1876; Chrysomya chloropyga (Wiedemann, 1818); Chrysomya marginalis (Wiedemann, 1830); and Chrysomya putoria (Wiedemann, 1830) (Diptera: Calliphoridae) are presented for the first time, and the following morphological structures are documented: pseudocephalon, antenna, maxillary palpus, facial mask, labial lobe, thoracic and abdominal spinulation, spiracular field, posterior spiracles, and anal pads. Light microscopy photographs and line illustrations are provided for the cephaloskeleton in lateral and ventral views, and the "ectostomal sclerite" and "chitinized teeth" of the cephaloskeleton are recognized as integral parts of the mouthhooks. New diagnostic features of the cephaloskeleton and the spinulation of the abdominal segments are described. These results allow refinement, clarification, and correction of earlier descriptions, which are reviewed. The relative taxonomic importance of various morphological characters of the first instars of necrophagous blow flies is discussed, and details of the cephaloskeleton and the spinulation of the abdominal segments are highlighted as the characters most useful for species identification. Finally, a key for identifying first instars of common African carrion blow flies is provided.
RATT: RFID Assisted Tracking Tile. Preliminary results.
Quinones, Dario R; Cuevas, Aaron; Cambra, Javier; Canals, Santiago; Moratal, David
2017-07-01
Behavior is one of the most important aspects of animal life. This behavior depends on the link between animals, their nervous systems and their environment. In order to study the behavior of laboratory animals several tools are needed, but a tracking tool is essential to perform a thorough behavioral study. Currently, several visual tracking tools are available. However, they have some drawbacks. For instance, when an animal is inside a cave, or is close to other animals, the tracking cameras cannot always detect the location or movement of this animal. This paper presents RFID Assisted Tracking Tile (RATT), a tracking system based on passive Radio Frequency Identification (RFID) technology in high frequency band according to ISO/IEC 15693. The RATT system is composed of electronic tiles that have nine active RFID antennas attached; in addition, it contains several overlapping passive coils to improve the magnetic field characteristics. Using several tiles, a large surface can be built on which the animals can move, allowing identification and tracking of their movements. This system, that could also be combined with a visual tracking system, paves the way for complete behavioral studies.
NASA Astrophysics Data System (ADS)
Smieska, Louisa Marion
Organic semiconductors could have wide-ranging applications in lightweight, efficient electronic circuits. However, several fundamental questions regarding organic electronic device behavior have not yet been fully addressed, including the nature of chemical charge traps, and robust models for injection and transport. Many studies focus on engineering devices through bulk transport measurements, but it is not always possible to infer the microscopic behavior leading to the observed measurements. In this thesis, we present scanning-probe microscope studies of organic semiconductor devices in an effort to connect local properties with local device behavior. First, we study the chemistry of charge trapping in pentacene transistors. Working devices are doped with known pentacene impurities and the extent of charge trap formation is mapped across the transistor channel. Trap-clearing spectroscopy is employed to measure an excitation of the pentacene charge trap species, enabling identification of the degradationrelated chemical trap in pentacene. Second, we examine transport and trapping in peryelene diimide (PDI) transistors. Local mobilities are extracted from surface potential profiles across a transistor channel, and charge injection kinetics are found to be highly sensitive to electrode cleanliness. Trap-clearing spectra generally resemble PDI absorption spectra, but one derivative yields evidence indicating variation in trap-clearing mechanisms for different surface chemistries. Trap formation rates are measured and found to be independent of surface chemistry, contradicting a proposed silanol trapping mechanism. Finally, we develop a variation of scanning Kelvin probe microscopy that enables measurement of electric fields through a position modulation. This method avoids taking a numeric derivative of potential, which can introduce high-frequency noise into the electric field signal. Preliminary data is presented, and the theoretical basis for electric field noise in both methods is examined.
Czyrska-Filemonowicz, A; Buffat, P A
2009-01-01
Surface processing of a Ti-6Al-4V alloy led to a complex multilayered microstructure containing several phases of the Ni-Ti-P-Al-O system, which improves the mechanical and tribological surface properties. The microstructure, chemical and phase compositions of the hard layer formed on the surface were investigated by LM, XRD, SEM as well as analytical/high-resolution TEM, STEM, EDS, electron diffraction and FIB. Phase identification based on electron diffraction, HRTEM and EDS microanalysis revealed the presence of several binary and ternary phases in the system Ti-Ni-P, sometimes with partial substitution of Ti by Al. However some phases, mainly nanoparticles, still remain not identified satisfactorily. Electron microscopy techniques used for identification of phases present in surface multilayers and some practical limits to their routine application are reminded here.
21 CFR 874.1120 - Electronic noise generator for audiometric testing.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electronic noise generator for audiometric testing... noise generator for audiometric testing. (a) Identification. An electronic noise generator for.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation...
Evaluating the Role of Intermediaries in the Electronic Value Chain.
ERIC Educational Resources Information Center
Janssen, Marijn; Sol, Henk G.
2000-01-01
Presents a business engineering methodology that supports the identification of electronic intermediary roles in the electronic value chain. The goal of this methodology is to give stakeholders insight into their current, and possible alternative, situations by means of visualization, to evaluate the added value of business models using…
21 CFR 874.1120 - Electronic noise generator for audiometric testing.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electronic noise generator for audiometric testing... noise generator for audiometric testing. (a) Identification. An electronic noise generator for.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation...
ERIC Educational Resources Information Center
Flexer, Carol; And Others
1990-01-01
Using sound field amplification which increased the intensity of the teacher's voice by 10 decibels, 9 primary-level children with developmental disabilities made fewer errors on a word identification task, were more relaxed, and responded more quickly than without amplification. (Author/JDD)
Jankowska, Petra J; Kong, Christine; Burke, Kevin; Harrington, Kevin J; Nutting, Christopher
2007-10-01
High dose irradiation of the posterior cervical lymph nodes usually employs applied electron fields to treat the target volume and maintain the spinal cord dose within tolerance. In the light of recent advances in elective lymph node localisation we investigated optimization of field shape and electron energy to treat this target volume. In this study, three sequential hypotheses were tested. Firstly, that customization of the electron fields based on the nodal PTV outlined gives better PTV coverage than conventional field delineation. Using the consensus guidelines, customization of the electron field shape was compared to conventional fields based on bony landmarks. Secondly, that selection of electron energy using DVHs for spinal cord and PTV improves the minimum dose to PTV. Electron dose-volume histograms (DVHs) for the PTV, spinal cord and para-vertebral muscles, were generated using the Monte Carlo electron algorithm. These DVHs were used to compare standard vs optimized electron energy calculations. Finally, that combination of field customization and electron energy optimization improves both the minimum and mean doses to PTV compared with current standard practice. Customized electron beam shaping based on the consensus guidelines led to fewer geographical misses than standard field shaping. Customized electron energy calculation led to higher minimum doses to the PTV. Overall, the customization of field shape and energy resulted in an improved mean dose to the PTV (92% vs 83% p=0.02) and a 27% improvement in the minimum dose delivered to the PTV (45% vs 18% p=0.0009). Optimization of electron field shape and beam energy based on current consensus guidelines led to significant improvement in PTV coverage and may reduce recurrence rates.
Bifocal Stereo for Multipath Person Re-Identification
NASA Astrophysics Data System (ADS)
Blott, G.; Heipke, C.
2017-11-01
This work presents an approach for the task of person re-identification by exploiting bifocal stereo cameras. Present monocular person re-identification approaches show a decreasing working distance, when increasing the image resolution to obtain a higher reidentification performance. We propose a novel 3D multipath bifocal approach, containing a rectilinear lens with larger focal length for long range distances and a fish eye lens of a smaller focal length for the near range. The person re-identification performance is at least on par with 2D re-identification approaches but the working distance of the approach is increased and on average 10% more re-identification performance can be achieved in the overlapping field of view compared to a single camera. In addition, the 3D information is exploited from the overlapping field of view to solve potential 2D ambiguities.
Identification of provenance rocks based on EPMA analyses of heavy minerals
NASA Astrophysics Data System (ADS)
Shimizu, M.; Sano, N.; Ueki, T.; Yonaga, Y.; Yasue, K. I.; Masakazu, N.
2017-12-01
Information on mountain building is significant in the field of geological disposal of high-level radioactive waste, because this affects long-term stability in groundwater flow system. Provenance analysis is one of effective approaches for understanding building process of mountains. Chemical compositions of heavy minerals, as well as their chronological data, can be an index for identification of provenance rocks. The accurate identification requires the measurement of as many grains as possible. In order to achieve an efficient provenance analysis, we developed a method for quick identification of heavy minerals using an Electron Probe Micro Analyzer (EPMA). In this method, heavy mineral grains extracted from a sample were aligned on a glass slide and mounted in a resin. Concentration of 28 elements was measured for 300-500 grains per sample using EPMA. To measure as many grains as possible, we prioritized swiftness of measurement over precision, configuring measurement time of about 3.5 minutes for each grain. Identification of heavy minerals was based on their chemical composition. We developed a Microsoft® Excel® spread sheet input criteria of mineral identification using a typical range of chemical compositions for each mineral. The grains of <80 wt.% or >110 wt.% total were rejected. The criteria of mineral identification were revised through the comparison between mineral identification by optical microscopy and chemical compositions of grains classified as "unknown minerals". Provenance rocks can be identified based on abundance ratio of identified minerals. If no significant difference of the abundance ratio was found among source rocks, chemical composition of specific minerals was used as another index. This method was applied to the sediments of some regions in Japan where provenance rocks had lithological variations but similar formation ages. Consequently, the provenance rocks were identified based on chemical compositions of heavy minerals resistant to weathering, such as zircon and ilmenite.This study was carried out under a contract with Ministry of Economy, Trade and Industry of Japan as part of its R&D supporting program for developing geological disposal technology.
Extensive electron transport and energization via multiple, localized dipolarizing flux bundles
NASA Astrophysics Data System (ADS)
Gabrielse, Christine; Angelopoulos, Vassilis; Harris, Camilla; Artemyev, Anton; Kepko, Larry; Runov, Andrei
2017-05-01
Using an analytical model of multiple dipolarizing flux bundles (DFBs) embedded in earthward traveling bursty bulk flows, we demonstrate how equatorially mirroring electrons can travel long distances and gain hundreds of keV from betatron acceleration. The model parameters are constrained by four Time History of Events and Macroscale Interactions during Substorms satellite observations, putting limits on the DFBs' speed, location, and magnetic and electric field magnitudes. We find that the sharp, localized peaks in magnetic field have such strong spatial gradients that energetic electrons ∇B drift in closed paths around the peaks as those peaks travel earthward. This is understood in terms of the third adiabatic invariant, which remains constant when the field changes on timescales longer than the electron's drift timescale: An energetic electron encircles a sharp peak in magnetic field in a closed path subtending an area of approximately constant flux. As the flux bundle magnetic field increases the electron's drift path area shrinks and the electron is prevented from escaping to the ambient plasma sheet, while it continues to gain energy via betatron acceleration. When the flux bundles arrive at and merge with the inner magnetosphere, where the background field is strong, the electrons suddenly gain access to previously closed drift paths around the Earth. DFBs are therefore instrumental in transporting and energizing energetic electrons over long distances along the magnetotail, bringing them to the inner magnetosphere and energizing them by hundreds of keV.
Electron holes in inhomogeneous magnetic field: Electron heating and electron hole evolution
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vasko, I. Y.; Space Research Institute of Russian Academy of Science, Moscow; Agapitov, O. V.
Electron holes are electrostatic non-linear structures widely observed in the space plasma. In the present paper, we analyze the process of energy exchange between electrons trapped within electron hole, untrapped electrons, and an electron hole propagating in a weakly inhomogeneous magnetic field. We show that as the electron hole propagates into the region with stronger magnetic field, trapped electrons are heated due to the conservation of the first adiabatic invariant. At the same time, the electron hole amplitude may increase or decrease in dependence on properties of distribution functions of trapped and untrapped resonant electrons. The energy gain of trappedmore » electrons is due to the energy losses of untrapped electrons and/or decrease of the electron hole energy. We stress that taking into account the energy exchange with untrapped electrons increases the lifetime of electron holes in inhomogeneous magnetic field. We illustrate the suggested mechanism for small-amplitude Schamel's [Phys. Scr. T2, 228–237 (1982)] electron holes and show that during propagation along a positive magnetic field gradient their amplitude should grow. Neglect of the energy exchange with untrapped electrons would result in the electron hole dissipation with only modest heating factor of trapped electrons. The suggested mechanism may contribute to generation of suprathermal electron fluxes in the space plasma.« less
SU-E-T-137: The Response of TLD-100 in Mixed Fields of Photons and Electrons.
Lawless, M; Junell, S; Hammer, C; DeWerd, L
2012-06-01
Thermoluminescent dosimeters are used routinely for dosimetric measurements of photon and electron fields. However, no work has been published characterizing TLDs for use in combined photon and electron fields. This work investigates the response of TLD-100 (LiF:Mg,Ti) in mixed fields of photon and electron beam qualities. TLDs were irradiated in a 6 MV photon beam, 6 MeV electron beam, and a NIST traceable cobalt-60 beam. TLDs were also irradiated in a mixed field of the electron and photon beams. All irradiations were normalized to absorbed dose to water as defined in the AAPM TG-51 report. The average response per dose (nC/Gy) for each linac beam quality was normalized to the average response per dose of the TLDs irradiated by the cobalt-60 standard.Irradiations were performed in a water tank and a Virtual Water™ phantom. Two TLD dose calibration curves for determining absorbed dose to water were generated using photon and electron field TLD response data. These individual beam quality dose calibration curves were applied to the TLDs irradiated in the mixed field. The TLD response in the mixed field was less sensitive than the response in the photon field and more sensitive than the response in the electron field. TLD determination of dose in the mixed field using the dose calibration curve generated by TLDs irradiated by photons resulted in an underestimation of the delivered dose, while the use of a dose calibration curve generated using electrons resulted in an overestimation of the delivered dose. The relative response of TLD-100 in mixed fields fell consistently between the photon nd electron relative responses. When using TLD-100 in mixed fields, the user must account for this intermediate response to avoid an over- or underestimation of the dose due to calibration in a single photon or electron field. © 2012 American Association of Physicists in Medicine.
[The application of radiological image in forensic medicine].
Zhang, Ji-Zong; Che, Hong-Min; Xu, Li-Xiang
2006-04-01
Personal identification is an important work in forensic investigation included sex discrimination, age and stature estimation. Human identification depended on radiological image technique analysis is a practice and proper method in forensic science field. This paper intended to understand the advantage and defect by reviewed the employing of forensic radiology in forensic science field broadly and provide a reference to perfect the application of forensic radiology in forensic science field.
77 FR 49834 - Agency Information Collection Activities: Proposed Collection; Comment Request
Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-17
... provide copies of licensee nuclear material event reports electronically or by hard copy to the NRC within... event information should be provided in a uniform electronic format, for assessment and identification...
Remote sensing technologies are a class of instrument and sensor systems that include laser imageries, imaging spectrometers, and visible to thermal infrared cameras. These systems have been successfully used for gas phase chemical compound identification in a variety of field e...
Talent Identification in Track and Field.
ERIC Educational Resources Information Center
Henson, Phillip; And Others
Talent identification in most sports occurs through mass participation and the process of natural selection; track and field does not enjoy such widespread participation. This paper reports on a project undertaken for the following purposes: improve the means by which youth with the potential for high level performance can be identified; develop…
Planetary Magnetic Fields: Planetary Interiors and Habitability
NASA Astrophysics Data System (ADS)
Lazio, T. Joseph W.; Shkolnik, Evgenya; Hallinan, Gregg; Planetary Habitability Study Team
2016-06-01
The W. M. Keck Institute for Space Studies (KISS) sponsored the Planetary Magnetic Fields: Planetary Interiors and Habitability Study to review the state of knowledge of extrasolar planetary magnetic fields and the prospects for their detection. There were multiple motivations for this Study. Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The Earth, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. In turn, these internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these in objects' interiors. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind or an orbiting satellite, a planet's magnetic field can produce intense electron cyclotron masers in its magnetic polar regions. The most well known example of this process in the solar system is the Jovian decametric emission, but all of the giant planets and the Earth contain similar electron cyclotron masers within their magnetospheres. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior--all of which will be difficult to determine by other means--as well as improved understanding of the basic planetary dynamo process. This report presents the findings from the Study, including potential mission concepts that emerged and future work in both modeling and observations. There was also an identification of that radio wavelength observations would likely be key to making significant progress in this field. The entire Study program would not have been possible without the generous support of the W. M. Keck Foundation. We thank Michele Judd, Tom Prince, and the staff of the W. M. Keck Institute for Space Studies for their hospitality and attention to detail, such that the Study participants could turn their attention to focused discussions and innovative ideas. We also thank Charles ("Chuck") Carter of Eagre Games, Inc., for his assistance with graphics.
NASA Astrophysics Data System (ADS)
Wang, Huanyu; Lu, Quanming; Huang, Can; Wang, Shui
2017-05-01
Secondary magnetic islands may be generated in the vicinity of an X line during magnetic reconnection. In this paper, by performing two-dimensional (2-D) particle-in-cell simulations, we investigate the role of a secondary magnetic island in electron acceleration during magnetic reconnection with a guide field. The electron motions are found to be adiabatic, and we analyze the contributions of the parallel electric field and Fermi and betatron mechanisms to electron acceleration in the secondary island during the evolution of magnetic reconnection. When the secondary island is formed, electrons are accelerated by the parallel electric field due to the existence of the reconnection electric field in the electron current sheet. Electrons can be accelerated by both the parallel electric field and Fermi mechanism when the secondary island begins to merge with the primary magnetic island, which is formed simultaneously with the appearance of X lines. With the increase in the guide field, the contributions of the Fermi mechanism to electron acceleration become less and less important. When the guide field is sufficiently large, the contribution of the Fermi mechanism is almost negligible.
Study on superconducting state parameters of Cu1-xZrx metallic glasses using model potentials
NASA Astrophysics Data System (ADS)
Jambusarwala, Tasneem S.; Gajjar, P. N.
2018-05-01
The superconducting state parameters (SSP) of Cu1-xZrx metallic glasses over the full range of concentration x of Zr have been investigated to study influence of various local pseudopotentials. The study includes the computation of electron-phonon coupling strength (λ), transition temperature (TC), isotope effect exponent (α) and effective interaction strength (N0V) using fourteen different forms of local model potentials. The local field correction function proposed by Taylor (T) is used. The influence of model potential on various parameters is ranging from 6% to 83% for pure Zr and 28% to 84% for pure Cu. The present study confirms that the identification of model potential is vital in studying Superconducting State Parameters.
In Situ Identification of Nanoparticle Structural Information Using Optical Microscopy.
Culver, Kayla S B; Liu, Tingting; Hryn, Alexander J; Fang, Ning; Odom, Teri W
2018-05-11
Diffraction-limited optical microscopy lacks the resolution to characterize directly nanoscale features of single nanoparticles. This paper describes how surprisingly rich structural features of small gold nanostars can be identified using differential interference contrast (DIC) microscopy. First, we established a library of structure-property relationships between nanoparticle shape and DIC optical image and then validated the correlation with electrodynamic simulations and electron microscopy. We found that DIC image patterns of single nanostars could be differentiated between 2D and 3D geometries. Also, DIC images could elucidate the symmetry properties and orientation of nanoparticles. Finally, we demonstrated how this wide-field optical technique can be used for in situ characterization of single nanoparticles rotating at a glass-water interface.
NASA Astrophysics Data System (ADS)
Bi, Chuan-Xing; Hu, Ding-Yu; Zhang, Yong-Bin; Jing, Wen-Qian
2015-06-01
In previous studies, an equivalent source method (ESM)-based technique for recovering the free sound field in a noisy environment has been successfully applied to exterior problems. In order to evaluate its performance when applied to a more general noisy environment, that technique is used to identify active sources inside cavities where the sound field is composed of the field radiated by active sources and that reflected by walls. A patch approach with two semi-closed surfaces covering the target active sources is presented to perform the measurements, and the field that would be radiated by these target active sources into free space is extracted from the mixed field by using the proposed technique, which will be further used as the input of nearfield acoustic holography for source identification. Simulation and experimental results validate the effectiveness of the proposed technique for source identification in cavities, and show the feasibility of performing the measurements with a double layer planar array.
Strong field acceleration and steering of ultrafast electron pulses from a sharp metallic nanotip.
Park, Doo Jae; Piglosiewicz, Bjoern; Schmidt, Slawa; Kollmann, Heiko; Mascheck, Manfred; Lienau, Christoph
2012-12-14
We report a strong, laser-field induced modification of the propagation direction of ultrashort electron pulses emitted from nanometer-sized gold tapers. Angle-resolved kinetic energy spectra of electrons emitted from such tips are recorded using ultrafast near-infrared light pulses of variable wavelength and intensity for excitation. For sufficiently long wavelengths, we observe a pronounced strong-field acceleration of electrons within the field gradient at the taper apex. We find a distinct narrowing of the emission cone angle of the fastest electrons. We ascribe this to the field-induced steering of subcycle electrons as opposed to the diverging emission of quiver electrons. Our findings are corroborated by simulations based on a modified Simpleman model incorporating the curved, vectorial field gradient in the vicinity of the tip. Our results indicate new pathways for designing highly directional nanometer-sized ultrafast electron sources.
Electron dynamics in a plasma focus. [electron acceleration
NASA Technical Reports Server (NTRS)
Hohl, F.; Gary, S. P.; Winters, P. A.
1977-01-01
Results are presented of a numerical integration of the three-dimensional relativistic equations of motion of electrons subject to given electric and magnetic fields deduced from experiments. Fields due to two different models are investigated. For the first model, the fields are those due to a circular distribution of axial current filaments. As the current filaments collapse toward the axis, large azimuthal magnetic and axial electric fields are induced. These fields effectively heat the electrons to a temperature of approximately 8 keV and accelerate electrons within the radius of the filaments to high axial velocities. Similar results are obtained for the current-reduction phase of focus formation. For the second model, the fields are those due to a uniform current distribution. Both the current-reduction and the compression phases were studied. These is little heating or acceleration of electrons during the compression phase because the electrons are tied to the magnetic field. However, during the current-reduction phase, electrons near the axis are accelerated toward the center electrode and reach energies of 100 keV. A criterion is obtained which limits the runaway electron current to about 400 A.
IDENTIFICATION OF NEW OZONE DISINFECTION BY PRODUCTS IN DRINKING WATER
Using a combination of spectral identification techniques-gas chromatography coupled with low- and high-resolution electron-impact mass spectrometry (GC/EI-MS), low- and high-resolution chemical ionization mass spectrometry (GC/CI-MS), and infrared spectroscopy (GC/ IR)-we identi...
Evans, D. A.; Brownlow, N. D.; Hersh, W. R.; Campbell, E. M.
1996-01-01
We discuss the development and evaluation of an automated procedure for extracting drug-dosage information from clinical narratives. The process was developed rapidly using existing technology and resources, including categories of terms from UMLS96. Evaluations over a large training and smaller test set of medical records demonstrate an approximately 80% rate of exact and partial matches' on target phrases, with few false positives and a modest rate of false negatives. The results suggest a strategy for automating general concept identification in electronic medical records. PMID:8947694
Gamma neutron assay method and apparatus
Cole, J.D.; Aryaeinejad, R.; Greenwood, R.C.
1995-01-03
The gamma neutron assay technique is an alternative method to standard safeguards techniques for the identification and assaying of special nuclear materials in a field or laboratory environment, as a tool for dismantlement and destruction of nuclear weapons, and to determine the isotopic ratios for a blend-down program on uranium. It is capable of determining the isotopic ratios of fissionable material from the spontaneous or induced fission of a sample to within approximately 0.5%. This is based upon the prompt coincidence relationships that occur in the fission process and the proton conservation and quasi-conservation of nuclear mass (A) that exists between the two fission fragments. The system is used in both passive (without an external neutron source) and active (with an external neutron source) mode. The apparatus consists of an array of neutron and gamma-ray detectors electronically connected to determine coincident events. The method can also be used to assay radioactive waste which contains fissile material, even in the presence of a high background radiation field. 7 figures.
Gamma neutron assay method and apparatus
Cole, Jerald D.; Aryaeinejad, Rahmat; Greenwood, Reginald C.
1995-01-01
The gamma neutron assay technique is an alternative method to standard safeguards techniques for the identification and assaying of special nuclear materials in a field or laboratory environment, as a tool for dismantlement and destruction of nuclear weapons, and to determine the isotopic ratios for a blend-down program on uranium. It is capable of determining the isotopic ratios of fissionable material from the spontaneous or induced fission of a sample to within approximately 0.5%. This is based upon the prompt coincidence relationships that occur in the fission process and the proton conservation and quasi-conservation of nuclear mass (A) that exists between the two fission fragments. The system is used in both passive (without an external neutron source and active (with an external neutron source) mode. The apparatus consists of an array of neutron and gamma-ray detectors electronically connected to determine coincident events. The method can also be used to assay radioactive waste which contains fissile material, even in the presence of a high background radiation field.
Li, Q; Nelson, C T; Hsu, S-L; Damodaran, A R; Li, L-L; Yadav, A K; McCarter, M; Martin, L W; Ramesh, R; Kalinin, S V
2017-11-13
Flexoelectricity refers to electric polarization generated by heterogeneous mechanical strains, namely strain gradients, in materials of arbitrary crystal symmetries. Despite more than 50 years of work on this effect, an accurate identification of its coupling strength remains an experimental challenge for most materials, which impedes its wide recognition. Here, we show the presence of flexoelectricity in the recently discovered polar vortices in PbTiO 3 /SrTiO 3 superlattices based on a combination of machine-learning analysis of the atomic-scale electron microscopy imaging data and phenomenological phase-field modeling. By scrutinizing the influence of flexocoupling on the global vortex structure, we match theory and experiment using computer vision methodologies to determine the flexoelectric coefficients for PbTiO 3 and SrTiO 3 . Our findings highlight the inherent, nontrivial role of flexoelectricity in the generation of emergent complex polarization morphologies and demonstrate a viable approach to delineating this effect, conducive to the deeper exploration of both topics.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zhou, X.; Gan, W.; Liu, S.
We investigate electron acceleration by electric fields induced by cascading reconnections in current sheets trailing coronal mass ejections via a test particle approach in the framework of the guiding-center approximation. Although the resistive electric field is much weaker than the inductive electric field, the electron acceleration is still dominated by the former. Anomalous resistivity η is switched on only in regions where the current carrier’s drift velocity is large enough. As a consequence, electron acceleration is very sensitive to the spatial distribution of the resistive electric fields, and electrons accelerated in different segments of the current sheet have different characteristics.more » Due to the geometry of the 2.5-dimensional electromagnetic fields and strong resistive electric field accelerations, accelerated high-energy electrons can be trapped in the corona, precipitating into the chromosphere or escaping into interplanetary space. The trapped and precipitating electrons can reach a few MeV within 1 s and have a very hard energy distribution. Spatial structure of the acceleration sites may also introduce breaks in the electron energy distribution. Most of the interplanetary electrons reach hundreds of keV with a softer distribution. To compare with observations of solar flares and electrons in solar energetic particle events, we derive hard X-ray spectra produced by the trapped and precipitating electrons, fluxes of the precipitating and interplanetary electrons, and electron spatial distributions.« less
Electron drift velocity and mobility in graphene
NASA Astrophysics Data System (ADS)
Dong, Hai-Ming; Duan, Yi-Feng; Huang, Fei; Liu, Jin-Long
2018-04-01
We present a theoretical study of the electric transport properties of graphene-substrate systems. The drift velocity, mobility, and temperature of the electrons are self-consistently determined using the Boltzmann equilibrium equations. It is revealed that the electronic transport exhibits a distinctly nonlinear behavior. A very high mobility is achieved with the increase of the electric fields increase. The electron velocity is not completely saturated with the increase of the electric field. The temperature of the hot electrons depends quasi-linearly on the electric field. In addition, we show that the electron velocity, mobility, and electron temperature are sensitive to the electron density. These findings could be employed for the application of graphene for high-field nano-electronic devices.
Kushida, Clete A; Nichols, Deborah A; Jadrnicek, Rik; Miller, Ric; Walsh, James K; Griffin, Kara
2012-07-01
De-identification and anonymization are strategies that are used to remove patient identifiers in electronic health record data. The use of these strategies in multicenter research studies is paramount in importance, given the need to share electronic health record data across multiple environments and institutions while safeguarding patient privacy. Systematic literature search using keywords of de-identify, deidentify, de-identification, deidentification, anonymize, anonymization, data scrubbing, and text scrubbing. Search was conducted up to June 30, 2011 and involved 6 different common literature databases. A total of 1798 prospective citations were identified, and 94 full-text articles met the criteria for review and the corresponding articles were obtained. Search results were supplemented by review of 26 additional full-text articles; a total of 120 full-text articles were reviewed. A final sample of 45 articles met inclusion criteria for review and discussion. Articles were grouped into text, images, and biological sample categories. For text-based strategies, the approaches were segregated into heuristic, lexical, and pattern-based systems versus statistical learning-based systems. For images, approaches that de-identified photographic facial images and magnetic resonance image data were described. For biological samples, approaches that managed the identifiers linked with these samples were discussed, particularly with respect to meeting the anonymization requirements needed for Institutional Review Board exemption under the Common Rule. Current de-identification strategies have their limitations, and statistical learning-based systems have distinct advantages over other approaches for the de-identification of free text. True anonymization is challenging, and further work is needed in the areas of de-identification of datasets and protection of genetic information.
Characteristics of DC electric fields at dipolarization fronts
NASA Astrophysics Data System (ADS)
Laakso, Harri; Escoubet, Philippe; Masson, Arnaud
2016-04-01
We investigate the characteristics of DC electric field at dipolarization fronts and BBF's using multi-point Cluster observations. There are plenty of important issues that are considered, such as what kind of DC electric fields exist in such events and what are their spatial scales. One can also recognize if electrons and ions perform ExB drift motions in these events. To investigate this, we take an advantage of five different DC electric field measurements in the plasma sheet available from the EFW double probe experiment, EDI electron drift instrument, CODIF and HIA ion spectrometers, and PEACE electron spectrometer. The calibrated observations of the three spectrometers are used to determine the proton and electron drift velocity and furthermore the DC electric field, assuming that the electron and proton velocity perpendicular to the magnetic field is dominated by the ExB drift motion. Naturally when ions and electrons do not perform a proper drift motion, which can happen in the plasma sheet, the estimated DC electric field from ion and electron motion is not correct. However, surprisingly often the DC electric fields estimated from electron and ion motions are identical suggesting that this field is a real DC electric field around the measurement point. This investigation also helps understand how well different measurements are calibrated.
Multi-point Measurements of Relativistic Electrons in the Magnetosphere
NASA Astrophysics Data System (ADS)
Li, X.; Selesnick, R.; Baker, D. N.; Blake, J. B.; Schiller, Q.; Blum, L. W.; Zhao, H.; Jaynes, A. N.; Kanekal, S.
2014-12-01
We take an advantage of five different DC electric field measurements in the plasma sheet available from the EFW double probe experiment, EDI electron drift instrument, CODIF and HIA ion spectrometers, and PEACE electron spectrometer on the four Cluster spacecraft. The calibrated observations of the three spectrometers are used to determine the proton and electron velocity moments. The velocity moments can be used to estimate the proton and electron drift velocity and furthermore the DC electric field, assuming that the electron and proton velocity perpendicular to the magnetic field is dominated by the ExB drift motion. Naturally when ions and electrons do not perform a proper drift motion, which can happen in the plasma sheet, the estimated DC electric field from ion and electron motion is not correct. However, surprisingly often the DC electric fields estimated from electron and ion motions are identical suggesting that this field is a real DC electric field around the measurement point. As the measurement techniques are so different, it is quite plausible that when two different measurements yield the same DC electric field, it is the correct field. All five measurements of the DC electric field are usually not simultaneously available, especially on Cluster 2 where CODIF and HIA are not operational, or on Cluster 4 where EDI is off. In this presentation we investigate DC electric field in various transient plasma sheet events such as dipolarization events and BBF's and how the five measurements agree or disagree. There are plenty of important issues that are considered, e.g., (1) what kind of DC electric fields exist in such events and what are their spatial scales, (2) do electrons and ions perform ExB drift motions in these events, and (3) how well the instruments have been calibrated.
NASA Astrophysics Data System (ADS)
Chang, Yuan-Ming; Lin, Che-Yi; Lin, Yen-Fu; Tsukagoshi, Kazuhito
2016-11-01
We present a review of recent developments in the synthesis, thickness identification, electronic properties, and possible applications of layered MoTe2 flakes. Special emphasis is made on two-dimensional (2D) MoTe2 semiconductors and the extensive research in recent years on their applications in electronics. Layered MoTe2 flakes have been the focus of substantial interest in the research community because of their fascinating characteristics, including an appropriate band gap and a simple fabrication method (exfoliation) to form layered nanomaterials. Our aim is to provide the readers an overview of layered MoTe2 flakes and to understand their properties, which may lead to their applications in micro- and nanoelectronics.
De-identification of health records using Anonym: effectiveness and robustness across datasets.
Zuccon, Guido; Kotzur, Daniel; Nguyen, Anthony; Bergheim, Anton
2014-07-01
Evaluate the effectiveness and robustness of Anonym, a tool for de-identifying free-text health records based on conditional random fields classifiers informed by linguistic and lexical features, as well as features extracted by pattern matching techniques. De-identification of personal health information in electronic health records is essential for the sharing and secondary usage of clinical data. De-identification tools that adapt to different sources of clinical data are attractive as they would require minimal intervention to guarantee high effectiveness. The effectiveness and robustness of Anonym are evaluated across multiple datasets, including the widely adopted Integrating Biology and the Bedside (i2b2) dataset, used for evaluation in a de-identification challenge. The datasets used here vary in type of health records, source of data, and their quality, with one of the datasets containing optical character recognition errors. Anonym identifies and removes up to 96.6% of personal health identifiers (recall) with a precision of up to 98.2% on the i2b2 dataset, outperforming the best system proposed in the i2b2 challenge. The effectiveness of Anonym across datasets is found to depend on the amount of information available for training. Findings show that Anonym compares to the best approach from the 2006 i2b2 shared task. It is easy to retrain Anonym with new datasets; if retrained, the system is robust to variations of training size, data type and quality in presence of sufficient training data. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.
The method for maintaining and recording electronic Chain-of-Custody (CoC) Records for CTEPP samples is summarized in this SOP. The CoC Records that will be logged electronically include the creation of a sample's identification code, bar code labels, and hard-copy CoC document...
NASA Astrophysics Data System (ADS)
Gamzina, Diana
Diana Gamzina March 2016 Mechanical and Aerospace Engineering Multiscale Thermo-Mechanical Design and Analysis of High Frequency and High Power Vacuum Electron Devices Abstract A methodology for performing thermo-mechanical design and analysis of high frequency and high average power vacuum electron devices is presented. This methodology results in a "first-pass" engineering design directly ready for manufacturing. The methodology includes establishment of thermal and mechanical boundary conditions, evaluation of convective film heat transfer coefficients, identification of material options, evaluation of temperature and stress field distributions, assessment of microscale effects on the stress state of the material, and fatigue analysis. The feature size of vacuum electron devices operating in the high frequency regime of 100 GHz to 1 THz is comparable to the microstructure of the materials employed for their fabrication. As a result, the thermo-mechanical performance of a device is affected by the local material microstructure. Such multiscale effects on the stress state are considered in the range of scales from about 10 microns up to a few millimeters. The design and analysis methodology is demonstrated on three separate microwave devices: a 95 GHz 10 kW cw sheet beam klystron, a 263 GHz 50 W long pulse wide-bandwidth sheet beam travelling wave tube, and a 346 GHz 1 W cw backward wave oscillator.
Electron Dynamics in Nanostructures in Strong Laser Fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kling, Matthias
2014-09-11
The goal of our research was to gain deeper insight into the collective electron dynamics in nanosystems in strong, ultrashort laser fields. The laser field strengths will be strong enough to extract and accelerate electrons from the nanoparticles and to transiently modify the materials electronic properties. We aimed to observe, with sub-cycle resolution reaching the attosecond time domain, how collective electronic excitations in nanoparticles are formed, how the strong field influences the optical and electrical properties of the nanomaterial, and how the excitations in the presence of strong fields decay.
Can physicians recognize their own patients in de-identified notes?
Meystre, Stéphane; Shen, Shuying; Hofmann, Deborah; Gundlapalli, Adi
2014-01-01
The adoption of Electronic Health Records is growing at a fast pace, and this growth results in very large quantities of patient clinical information becoming available in electronic format, with tremendous potentials, but also equally growing concern for patient confidentiality breaches. De-identification of patient information has been proposed as a solution to both facilitate secondary uses of clinical information, and protect patient information confidentiality. Automated approaches based on Natural Language Processing have been implemented and evaluated, allowing for much faster text de-identification than manual approaches. A U.S. Veterans Affairs clinical text de-identification project focused on investigating the current state of the art of automatic clinical text de-identification, on developing a best-of-breed de-identification application for clinical documents, and on evaluating its impact on subsequent text uses and the risk for re-identification. To evaluate this risk, we de-identified discharge summaries from 86 patients using our 'best-of-breed' text de-identification application with resynthesis of the identifiers detected. We then asked physicians working in the ward the patients were hospitalized in if they could recognize these patients when reading the de-identified documents. Each document was examined by at least one resident and one attending physician, and with 4.65% of the documents, physicians thought they recognized the patient because of specific clinical information, but after verification, none was correctly re-identified.
31 CFR 370.1 - What special terms do I need to know to understand this part?
Code of Federal Regulations, 2014 CFR
2014-07-01
... electronic medium and is retrievable in perceivable form. Electronic signature means a signature of an...Direct account number, your social security account number or employer identification number, and your...
31 CFR 370.1 - What special terms do I need to know to understand this part?
Code of Federal Regulations, 2011 CFR
2011-07-01
... electronic medium and is retrievable in perceivable form. Electronic signature means a signature of an...Direct account number, your social security account number or employer identification number, and your...
31 CFR 370.1 - What special terms do I need to know to understand this part?
Code of Federal Regulations, 2012 CFR
2012-07-01
... electronic medium and is retrievable in perceivable form. Electronic signature means a signature of an...Direct account number, your social security account number or employer identification number, and your...
Adapting livestock behaviour to achieve management goals
USDA-ARS?s Scientific Manuscript database
Using livestock to efficiently achieve management goals requires melding animal behavior with mechanical and electronic equipment. Practices such as autonomously obtaining individual animal liveweight when combined with individual animal electronic identification can produce numerous cost saving ad...
31 CFR 370.1 - What special terms do I need to know to understand this part?
Code of Federal Regulations, 2013 CFR
2013-07-01
... electronic medium and is retrievable in perceivable form. Electronic signature means a signature of an...Direct account number, your social security account number or employer identification number, and your...
DOT National Transportation Integrated Search
2007-10-05
Many electronic displays of aeronautical charting information currently use different symbols for common display elements, creating the risk of confusion and misinterpretation. The SAE International Aerospace Behavior and Technology (G-10) Aeronautic...
F-22 Plus-Up Environmental Assessment Joint Base Elmendorf-Richardson, Alaska
2011-06-01
Page 1-3 The F-22 has enhanced low visibilty, speed, maneuverability, electronics , and maintainability. The proposal is to beddown six primary...tactics, radar employment, identification, weapons employment, defensive response, electronic countermeasures, and electronic counter countermeasures...flare, and electronic countermeasures. Warning Area, MOA, and ATCAA 2,000 AGL to 60,000 MSL 0.75 to 1.5 hour F-22 Plus-Up Environmental
F-22 Operational Squadron and T-38 Detachment Beddown at Tyndall Air Force Base, Florida
2011-08-01
tactics, radar employment, identification, weapons employment, defensive response, electronic countermeasures, and electronic counter...use, and electronic countermeasures. Warning Area, MOA, and ATCAA 2,000 AGL to 60,000 MSL 0.75 to 1.5 hour (Dissimilar) Air Combat...night), air refueling, and strike-force rendezvous, conducting air-to-ground strikes, strike force defense and escort, air intercepts, electronic
Characteristics of DC electric fields in transient plasma sheet events
NASA Astrophysics Data System (ADS)
Laakso, H. E.; Escoubet, C. P.; Masson, A.
2015-12-01
We take an advantage of five different DC electric field measurements in the plasma sheet available from the EFW double probe experiment, EDI electron drift instrument, CODIF and HIA ion spectrometers, and PEACE electron spectrometer on the four Cluster spacecraft. The calibrated observations of the three spectrometers are used to determine the proton and electron velocity moments. The velocity moments can be used to estimate the proton and electron drift velocity and furthermore the DC electric field, assuming that the electron and proton velocity perpendicular to the magnetic field is dominated by the ExB drift motion. Naturally when ions and electrons do not perform a proper drift motion, which can happen in the plasma sheet, the estimated DC electric field from ion and electron motion is not correct. However, surprisingly often the DC electric fields estimated from electron and ion motions are identical suggesting that this field is a real DC electric field around the measurement point. As the measurement techniques are so different, it is quite plausible that when two different measurements yield the same DC electric field, it is the correct field. All five measurements of the DC electric field are usually not simultaneously available, especially on Cluster 2 where CODIF and HIA are not operational, or on Cluster 4 where EDI is off. In this presentation we investigate DC electric field in various transient plasma sheet events such as dipolarization events and BBF's and how the five measurements agree or disagree. There are plenty of important issues that are considered, e.g., (1) what kind of DC electric fields exist in such events and what are their spatial scales, (2) do electrons and ions perform ExB drift motions in these events, and (3) how well the instruments have been calibrated.
Identification of Disciplines and Fields. Edis Task I Report, Work Unit 1.4.
ERIC Educational Resources Information Center
Howard Research Co., Arlington, VA.
This report presents the identification and definitions of subject oriented engineering and scientific disciplines and fields which are included in the EDIS Subject Categories. The discussion is extended to include the mix of subjects with other orientations, such as Item, Mission-Project, Expertise and Data Bank Categories. Sample queries are…
General Anisotropy Identification of Paperboard with Virtual Fields Method
J.M. Considine; F. Pierron; K.T. Turner; D.W. Vahey
2014-01-01
This work extends previous efforts in plate bending of Virtual Fields Method (VFM) parameter identification to include a general 2-D anisotropicmaterial. Such an extension was needed for instances in which material principal directions are unknown or when specimen orientation is not aligned with material principal directions. A new fixture with a multiaxial force...
Field-deployable gamma-radiation detectors for DHS use
NASA Astrophysics Data System (ADS)
Mukhopadhyay, Sanjoy
2007-09-01
Recently, the Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial off-the-shelf and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable gamma radiation detectors that are attempting to meet the DNDO specifications. Commercially available, transportable, handheld radio isotope identification devices (RIID) are inadequate for DHS' requirements in terms of sensitivity, resolution, response time, and reach-back capability. The leading commercial vendor manufacturing handheld gamma spectrometer in the United States is Thermo Electron Corporation. Thermo Electron's identiFINDER TM, which primarily uses sodium iodide crystals (3.18 x 2.54cm cylinders) as gamma detectors, has a Full-Width-at-Half-Maximum energy resolution of 7 percent at 662 keV. Thermo Electron has just recently come up with a reach-back capability patented as RadReachBack TM that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field1. The current project has the goal to build a prototype handheld gamma spectrometer, equipped with a digital camera and an embedded cell phone to be used as an RIID with higher sensitivity, better resolution, and faster response time (able to detect the presence of gamma-emitting radio isotopes within 5 seconds of approach), which will make it useful as a field deployable tool. The handheld equipment continuously monitors the ambient gamma radiation, and, if it comes across any radiation anomalies with higher than normal gamma gross counts, it sets an alarm condition. When a substantial alarm level is reached, the system automatically triggers the saving of relevant spectral data and software-triggers the digital camera to take a snapshot. The spectral data including in situ analysis and the imagery data will be packaged in a suitable format and sent to a command post using an imbedded cell phone.
The effect of the earth's and stray magnetic fields on mobile mass spectrometer systems.
Bell, Ryan J; Davey, Nicholas G; Martinsen, Morten; Short, R Timothy; Gill, Chris G; Krogh, Erik T
2015-02-01
Development of small, field-portable mass spectrometers has enabled a rapid growth of in-field measurements on mobile platforms. In such in-field measurements, unexpected signal variability has been observed by the authors in portable ion traps with internal electron ionization. The orientation of magnetic fields (such as the Earth's) relative to the ionization electron beam trajectory can significantly alter the electron flux into a quadrupole ion trap, resulting in significant changes in the instrumental sensitivity. Instrument simulations and experiments were performed relative to the earth's magnetic field to assess the importance of (1) nonpoint-source electron sources, (2) vertical versus horizontal electron beam orientation, and (3) secondary magnetic fields created by the instrument itself. Electron lens focus effects were explored by additional simulations, and were paralleled by experiments performed with a mass spectrometer mounted on a rotating platform. Additionally, magnetically permeable metals were used to shield (1) the entire instrument from the Earth's magnetic field, and (2) the electron beam from both the Earth's and instrument's magnetic fields. Both simulation and experimental results suggest the predominant influence on directionally dependent signal variability is the result of the summation of two magnetic vectors. As such, the most effective method for reducing this effect is the shielding of the electron beam from both magnetic vectors, thus improving electron beam alignment and removing any directional dependency. The improved ionizing electron beam alignment also allows for significant improvements in overall instrument sensitivity.
Allen, Felicity; Pon, Allison; Greiner, Russ; Wishart, David
2016-08-02
We describe a tool, competitive fragmentation modeling for electron ionization (CFM-EI) that, given a chemical structure (e.g., in SMILES or InChI format), computationally predicts an electron ionization mass spectrum (EI-MS) (i.e., the type of mass spectrum commonly generated by gas chromatography mass spectrometry). The predicted spectra produced by this tool can be used for putative compound identification, complementing measured spectra in reference databases by expanding the range of compounds able to be considered when availability of measured spectra is limited. The tool extends CFM-ESI, a recently developed method for computational prediction of electrospray tandem mass spectra (ESI-MS/MS), but unlike CFM-ESI, CFM-EI can handle odd-electron ions and isotopes and incorporates an artificial neural network. Tests on EI-MS data from the NIST database demonstrate that CFM-EI is able to model fragmentation likelihoods in low-resolution EI-MS data, producing predicted spectra whose dot product scores are significantly better than full enumeration "bar-code" spectra. CFM-EI also outperformed previously reported results for MetFrag, MOLGEN-MS, and Mass Frontier on one compound identification task. It also outperformed MetFrag in a range of other compound identification tasks involving a much larger data set, containing both derivatized and nonderivatized compounds. While replicate EI-MS measurements of chemical standards are still a more accurate point of comparison, CFM-EI's predictions provide a much-needed alternative when no reference standard is available for measurement. CFM-EI is available at https://sourceforge.net/projects/cfm-id/ for download and http://cfmid.wishartlab.com as a web service.
NASA Astrophysics Data System (ADS)
Scudder, J. D.; Mozer, F. S.
2005-05-01
Abrupt, intense bipolar and unipolar electric spikes with E > 100mV/m surveyed over 3 years of Polar data (Mozer et al 2005) have been organized to answer the limited question: can they be involved in the local demagnetization of thermal electrons? We determine a lower bound on the electric strength sufficient to cause non-gyrotropic effects on the electron pressure tensor of the form E>E*=B{we}/{8c Im}, where B is the ambient magnetic field strength, we=√2kTe/me, c is the speed of light, and Im is an electron velocity space weighted average displacement along the electric field while transiting the layer (assumed localized with a scale Δ x=a ρe, where ρe is the electron thermal gyroradius). The variation of Im as a function of a for equal mean energy Maxwellian and more typical κ distributions seen in the Earth's magnetosphere provides strong evidence that the surveyed electric field spikes are generally smaller than E* (assuming ≍ 1), although 23% (n=57) exceed E* . Only 11% (n=6) of the bipolar class exceed E* ; the frequency of occurrence distribution for the bipolar class of spikes is peaked at 0.1E*. The unipolar occurrence is flat below E*, but has a significant 26% subgroup (n=51) that exceed E* . While E* does not depend on the ambient density, the occurrence distribution of all demagnetizing events is well organized by the ratio ℜ=λDe/ρe=&Omegace/ωpe, residing almost exclusively in the regime ℜ <1. Spikes with E < E* generally occur with ℜ >1 . All the electrostatic spike events surveyed occur in the regime 10-8≤βe≤3×10-2. The demagnetizing events of either class occupy the more restricted low beta regime 10-3≤βe≤3×10-2. Because these demagnetizing events occur in βe ≪ 1 they would not, however, be considered unmagnetized at current channels as thin as the electron skin depth, de, since for such current channels ρe ≡ βe-1/2de ≪ de. As a group the subset of unipolar events with E > E* are consistently understood as sites where the electron pressure tensor could become deformed from cylindrical symmetry by electric field enhancement in layers with scale sizes up to the local thermal electron's gyroradius. Such a deformation is critical for a viable mechanism that supports collisionless reconnection. After selecting events as demagnetizing based on the size of the relevant forces and work done, the geophysical locale of their detection has been investigated. Previously, all E spikes in this survey were found near the invariant latitudes Λ of the earth's magnetic cusps but at all magnetic local times. The demagnetizing events identified here via E* are strongly organized at magnetic local noon (with a secondary, much shallower maximum at local magnetic midnight), occur preferentially at orbit apogee, and without significant preference for the magnetic latitude of the spacecraft. These geophysical organizations are consistent with the demagnetizing E spikes as indices of ongoing, collisionless reconnection in low βe regimes at the earth's subsolar magnetopause. The identification of this sub-class of electric spikes at low βe with E>E* widens the observed venues in the E and B fields where topology changing departures from ideal MHD should be anticipated in collisionless astrophysical plasmas.
Chapter 01: Wood identification and pattern recognition
Alex Wiedenhoeft
2011-01-01
Wood identification is a combination of art and science. Although the bulk of this manual focuses on the scientific characteristics used to make accurate field identifications of wood, the contribution of the artistic component to the identification process should be neither overlooked nor understated. Though the accumulation of scientific knowledge and experience is...
NASA Astrophysics Data System (ADS)
Akatsuka, Hiroshi; Takeda, Jun; Nezu, Atsushi
2016-09-01
To examine of the effect of the radial electric field on the azimuthal electron motion under E × B field for plasmas with magnetized electrons and non-magnetized ions, an experimental study is conducted by a stationary plasma flow. The argon plasma flow is generated by a DC arc generator under atmospheric pressure, followed by a cw expansion into a rarefied gas-wind tunnel with a uniform magnetic field 0 . 16 T. Inside one of the magnets, we set a ring electrode to apply the radial electric field. We applied an up-down probe for the analysis of the electron motion, where one of the tips is also used as a Langmuir probe to measure electron temperature, density and the space potential. We found that the order of the radial electric field is about several hundred V/m, which should be caused by the difference in the magnetization between electrons and ions. Electron saturation current indicates the existence of the E × B rotation of electrons, whose order is about 2000 - 4000 m/s. The order of the observed electron drift velocity is consistent with the theoretical value calculated from the applied magnetic field and the measured electric field deduced from the space potential.
NASA Astrophysics Data System (ADS)
Chen, L.-J.; Hesse, M.; Wang, S.; Gershman, D.; Ergun, R. E.; Burch, J.; Bessho, N.; Torbert, R. B.; Giles, B.; Webster, J.; Pollock, C.; Dorelli, J.; Moore, T.; Paterson, W.; Lavraud, B.; Strangeway, R.; Russell, C.; Khotyaintsev, Y.; Lindqvist, P.-A.; Avanov, L.
2017-05-01
An electron diffusion region (EDR) in magnetic reconnection with a guide magnetic field approximately 0.2 times the reconnecting component is encountered by the four Magnetospheric Multiscale spacecraft at the Earth's magnetopause. The distinct substructures in the EDR on both sides of the reconnecting current sheet are visualized with electron distribution functions that are 2 orders of magnitude higher cadence than ever achieved to enable the following new findings: (1) Motion of the demagnetized electrons plays an important role to sustain the reconnection current and contributes to the dissipation due to the nonideal electric field, (2) the finite guide field dominates over the Hall magnetic field in an electron-scale region in the exhaust and modifies the electron flow dynamics in the EDR, (3) the reconnection current is in part carried by inflowing field-aligned electrons in the magnetosphere part of the EDR, and (4) the reconnection electric field measured by multiple spacecraft is uniform over at least eight electron skin depths and corresponds to a reconnection rate of approximately 0.1. The observations establish the first look at the structure of the EDR under a weak but not negligible guide field.
APPLYING TOXICITY IDENTIFICATION PROCEDURES TO FIELD COLLECTED SEDIMENTS
Identification of specific causes of sediment toxicity can allow for much more focused risk assessment and management decision making. We have been developing toxicity identification evaluation (TIE) methods for contaminated sediments and focusing on three toxicant groups (ammoni...
Acceleration of auroral electrons in parallel electric fields
NASA Technical Reports Server (NTRS)
Kaufmann, R. L.; Walker, D. N.; Arnoldy, R. L.
1976-01-01
Rocket observations of auroral electrons are compared with the predictions of a number of theoretical acceleration mechanisms that involve an electric field parallel to the earth's magnetic field. The theoretical models are discussed in terms of required plasma sources, the location of the acceleration region, and properties of necessary wave-particle scattering mechanisms. We have been unable to find any steady state scatter-free electric field configuration that predicts electron flux distributions in agreement with the observations. The addition of a fluctuating electric field or wave-particle scattering several thousand kilometers above the rocket can modify the theoretical flux distributions so that they agree with measurements. The presence of very narrow energy peaks in the flux contours implies a characteristic temperature of several tens of electron volts or less for the source of field-aligned auroral electrons and a temperature of several hundred electron volts or less for the relatively isotropic 'monoenergetic' auroral electrons. The temperature of the field-aligned electrons is more representative of the magnetosheath or possibly the ionosphere as a source region than of the plasma sheet.
Guaraldi, Federica; Parasiliti-Caprino, Mirko; Goggi, Riccardo; Beccuti, Guglielmo; Grottoli, Silvia; Arvat, Emanuela; Ghizzoni, Lucia; Ghigo, Ezio; Giordano, Roberta; Gori, Davide
2014-12-01
The exponential growth of scientific literature available through electronic databases (namely PubMed) has increased the chance of finding interesting articles. At the same time, search has become more complicated, time consuming, and at risk of missing important information. Therefore, optimized strategies have to be adopted to maximize searching impact. The aim of this study was to formulate efficient strings to search PubMed for etiologic associations between adrenal disorders (ADs) and other conditions. A comprehensive list of terms identifying endogenous conditions primarily affecting adrenals was compiled. An ad hoc analysis was performed to find the best way to express each term in order to find the highest number of potentially pertinent articles in PubMed. A predefined number of retrieved abstracts were read to assess their association with ADs' etiology. A more sensitive (providing the largest literature coverage) and a more specific (including only those terms retrieving >40 % of potentially pertinent articles) string were formulated. Various researches were performed to assess strings' ability to identify articles of interest in comparison with non-optimized literature searches. We formulated optimized, ready applicable tools for the identification of the literature assessing etiologic associations in the field of ADs using PubMed, and demonstrated the advantages deriving from their application. Detailed description of the methodological process is also provided, so that this work can easily be translated to other fields of practice.
Shrestha, Sachin L; Breen, Andrew J; Trimby, Patrick; Proust, Gwénaëlle; Ringer, Simon P; Cairney, Julie M
2014-02-01
The identification and quantification of the different ferrite microconstituents in steels has long been a major challenge for metallurgists. Manual point counting from images obtained by optical and scanning electron microscopy (SEM) is commonly used for this purpose. While classification systems exist, the complexity of steel microstructures means that identifying and quantifying these phases is still a great challenge. Moreover, point counting is extremely tedious, time consuming, and subject to operator bias. This paper presents a new automated identification and quantification technique for the characterisation of complex ferrite microstructures by electron backscatter diffraction (EBSD). This technique takes advantage of the fact that different classes of ferrite exhibit preferential grain boundary misorientations, aspect ratios and mean misorientation, all of which can be detected using current EBSD software. These characteristics are set as criteria for identification and linked to grain size to determine the area fractions. The results of this method were evaluated by comparing the new automated technique with point counting results. The technique could easily be applied to a range of other steel microstructures. © 2013 Published by Elsevier B.V.
Composition of plastics from waste electrical and electronic equipment (WEEE) by direct sampling.
Martinho, Graça; Pires, Ana; Saraiva, Luanha; Ribeiro, Rita
2012-06-01
This paper describes a direct analysis study carried out in a recycling unit for waste electrical and electronic equipment (WEEE) in Portugal to characterize the plastic constituents of WEEE. Approximately 3400 items, including cooling appliances, small WEEE, printers, copying equipment, central processing units, cathode ray tube (CRT) monitors and CRT televisions were characterized, with the analysis finding around 6000 kg of plastics with several polymer types. The most common polymers are polystyrene, acrylonitrile-butadiene-styrene, polycarbonate blends, high-impact polystyrene and polypropylene. Additives to darken color are common contaminants in these plastics when used in CRT televisions and small WEEE. These additives can make plastic identification difficult, along with missing polymer identification and flame retardant identification marks. These drawbacks contribute to the inefficiency of manual dismantling of WEEE, which is the typical recycling process in Portugal. The information found here can be used to set a baseline for the plastics recycling industry and provide information for ecodesign in electrical and electronic equipment production. Copyright © 2012 Elsevier Ltd. All rights reserved.
USDA-ARS?s Scientific Manuscript database
Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the palm aphid, Cerataphis brasiliensis, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures...
NASA Astrophysics Data System (ADS)
Gao, Yanlin; Okada, Susumu
2017-05-01
Using the density functional theory, we studied the electronic structures of zigzag graphene nanoribbons with hydroxyl, H, ketone, aldehyde, or carboxyl terminations under a lateral electric field. The critical electric field for electron emission is proportional to the work function of the functionalized edges except the hydroxylated edge, which leads to the anomalous electric field outside the edge, owing to the electrons in the nearly free electron (NFE) state in the vacuum region. The strong electric field also causes a potential barrier for the electron emission from the H-terminated edge owing to the downward shift of the NFE state.
NASA Astrophysics Data System (ADS)
Zhao, Pengcheng; Guo, Lixin; Shu, Panpan
2016-08-01
The gas breakdown induced by a square microwave pulse with a crossed dc magnetic field is investigated using the electron fluid model, in which the accurate electron energy distribution functions are adopted. Simulation results show that at low gas pressures the dc magnetic field of a few tenths of a tesla can prolong the breakdown formation time by reducing the mean electron energy. With the gas pressure increasing, the higher dc magnetic field is required to suppress the microwave breakdown. The electric field along the microwave propagation direction generated due to the motion of electrons obviously increases with the dc magnetic field, but it is much less than the incident electric field. The breakdown predictions of the electron fluid model agree very well with the particle-in-cell-Monte Carlo collision simulations as well as the scaling law for the microwave gas breakdown.
Applications of emerging transmission electron microscopy technology in PCD research and diagnosis.
Shoemark, Amelia
2017-01-01
Primary Ciliary Dyskinesia (PCD) is a heterogeneous genetic condition characterized by dysfunction of motile cilia. Patients suffer from chronic infection and inflammation of the upper and lower respiratory tract. Diagnosis of PCD is confirmed by identification of a hallmark defect of ciliary ultrastructure or by identification of biallelic pathogenic mutations in a known PCD gene. Since the first description of PCD in 1976, assessment of ciliary ultrastructure by transmission electron microscopy (TEM) has been central to diagnosis and research. Electron tomography is a technique whereby a series of transmission electron micrographs are collected at different angles and reconstructed into a single 3D model of a specimen. Electron tomography provides improved spatial information and resolution compared to a single micrograph. Research by electron tomography has revealed new insight into ciliary ultrastructure and consequently ciliary function at a molecular and cellular level. Gene discovery studies in PCD have utilized electron tomography to define the structural consequences of variants in cilia genes. Modern transmission electron microscopes capable of electron tomography are increasingly being installed in clinical laboratories. This presents the possibility for the use of tomography technique in a diagnostic setting. This review describes the electron tomography technique, the contribution tomography has made to the understanding of basic cilia structure and function and finally the potential of the technique for use in PCD diagnosis.
RESULTS OF APPLYING TOXICITY IDENTIFICATION PROCEDURES TO FIELD COLLECTED SEDIMENTS
Identification of specific causes of sediment toxicity can allow for much more focused risk assessment and management decision making. We have been developing toxicity identification evaluation TIE) methods for contaminated sediments and are focusing on three toxicant groups (amm...
Quantum control via a genetic algorithm of the field ionization pathway of a Rydberg electron
NASA Astrophysics Data System (ADS)
Gregoric, Vincent C.; Kang, Xinyue; Liu, Zhimin Cheryl; Rowley, Zoe A.; Carroll, Thomas J.; Noel, Michael W.
2017-08-01
Quantum control of the pathway along which a Rydberg electron field ionizes is experimentally and computationally demonstrated. Selective field ionization is typically done with a slowly rising electric field pulse. The (1/n*)4 scaling of the classical ionization threshold leads to a rough mapping between arrival time of the electron signal and principal quantum number of the Rydberg electron. This is complicated by the many avoided level crossings that the electron must traverse on the way to ionization, which in general leads to broadening of the time-resolved field ionization signal. In order to control the ionization pathway, thus directing the signal to the desired arrival time, a perturbing electric field produced by an arbitrary wave-form generator is added to a slowly rising electric field. A genetic algorithm evolves the perturbing field in an effort to achieve the target time-resolved field ionization signal.
NASA Astrophysics Data System (ADS)
Copeland, Patricia L.; Shugars, James
1997-02-01
The Federal Bureau of Investigation (FBI) is currently developing a new system to provide timely criminal and civil identities and criminal history information to the nation's local, state, and federal users. The Integrated Automated Fingerprint Identification System (IAFIS), an upgrade to the existing Identification Division Automated Services (IDAS) System, is scheduled for implementation in 1999 at the new FBI facility in Clarksburg, West Virginia. IAFIS will offer new capabilities for electronic transmittal of fingerprint cards to the FBI, an improved fingerprint matching algorithm, and electronic maintenance of fingerprints and photo images. The Interstate Identification Index (III/FBI) System is one of three segments comprising the umbrella IAFIS System. III/FBI provides repository, maintenance, and dissemination capabilities for the 40 million subject national criminal history database. III/FBI will perform over 1 million name searches each day. Demanding performance, reliability/maintainability/availability, and flexibility/expandability requirements make III/FBI an architectural challenge to the system developers. This paper will discuss these driving requirements and present the technical solutions in terms of leading edge hardware and software.
Multi-field electron emission pattern of 2D emitter: Illustrated with graphene
NASA Astrophysics Data System (ADS)
Luo, Ma; Li, Zhibing
2016-11-01
The mechanism of laser-assisted multi-field electron emission of two-dimensional emitters is investigated theoretically. The process is basically a cold field electron emission but having more controllable components: a uniform electric field controls the emission potential barrier, a magnetic field controls the quantum states of the emitter, while an optical field controls electron populations of specified quantum states. It provides a highly orientational vacuum electron line source whose divergence angle over the beam plane is inversely proportional to square root of the emitter height. Calculations are carried out for graphene with the armchair emission edge, as a concrete example. The rate equation incorporating the optical excitation, phonon scattering, and thermal relaxation is solved in the quasi-equilibrium approximation for electron population in the bands. The far-field emission patterns, that inherit the features of the Landau bands, are obtained. It is found that the optical field generates a characteristic structure at one wing of the emission pattern.
X-ray tube with magnetic electron steering
Reed, Kim W.; Turman, Bobby N.; Kaye, Ronald J.; Schneider, Larry X.
2000-01-01
An X-ray tube uses a magnetic field to steer electrons. The magnetic field urges electrons toward the anode, increasing the proportion of electrons emitted from the cathode that reach desired portions of the anode and consequently contribute to X-ray production. The magnetic field also urges electrons reflected from the anode back to the anode, further increasing the efficiency of the tube.
Self-Consistent Superthermal Electron Effects on Plasmaspheric Refilling
NASA Technical Reports Server (NTRS)
Liemohn, M. W.; Khazanov, G. V.; Moore, T. E.; Guiter, S. M.
1997-01-01
The effects of self-consistently including superthermal electrons in the definition of the ambipolar electric field are investigated for the case of plasmaspheric refilling after a geomagnetic storm. By using the total electron population in the hydrodynamic equations, a method for incorporating superthermal electron parameters in the electric field and electron temperature calculation is developed. Also, the ambipolar electric field is included in the kinetic equation for the superthermal electrons through a change of variables using the total energy and the first adiabatic invariant. Calculations based on these changes are performed by coupling time-dependent models of the thermal plasma and superthermal electrons. Results from this treatment of the electric field and the self-consistent development of the solution are discussed in detail. Specifically, there is a decreased thermal electron density in the plasmasphere during the first few minutes of refilling, a slightly accelerated proton shock front, and a decreased superthermal electron flux due to the deceleration by the electric field. The timescales of plasmaspheric refilling are discussed and determined to be somewhat shorter than previously calculated for the thermal plasma and superthermal electron population due to the effects of the field-aligned potential.
Ludvigsson, Linus; Isaxon, Christina; Nilsson, Patrik T; Tinnerberg, Hakan; Messing, Maria E; Rissler, Jenny; Skaug, Vidar; Gudmundsson, Anders; Bohgard, Mats; Hedmer, Maria; Pagels, Joakim
2016-05-01
An increased production and use of carbon nanotubes (CNTs) is occurring worldwide. In parallel, a growing concern is emerging on the adverse effects the unintentional inhalation of CNTs can have on humans. There is currently a debate regarding which exposure metrics and measurement strategies are the most relevant to investigate workplace exposures to CNTs. This study investigated workplace CNT emissions using a combination of time-integrated filter sampling for scanning electron microscopy (SEM) and direct reading aerosol instruments (DRIs). Field measurements were performed during small-scale manufacturing of multiwalled carbon nanotubes using the arc discharge technique. Measurements with highly time- and size-resolved DRI techniques were carried out both in the emission and background (far-field) zones. Novel classifications and counting criteria were set up for the SEM method. Three classes of CNT-containing particles were defined: type 1: particles with aspect ratio length:width >3:1 (fibrous particles); type 2: particles without fibre characteristics but with high CNT content; and type 3: particles with visible embedded CNTs. Offline sampling using SEM showed emissions of CNT-containing particles in 5 out of 11 work tasks. The particles were classified into the three classes, of which type 1, fibrous CNT particles contributed 37%. The concentration of all CNT-containing particles and the occurrence of the particle classes varied strongly between work tasks. Based on the emission measurements, it was assessed that more than 85% of the exposure originated from open handling of CNT powder during the Sieving, mechanical work-up, and packaging work task. The DRI measurements provided complementary information, which combined with SEM provided information on: (i) the background adjusted emission concentration from each work task in different particle size ranges, (ii) identification of the key procedures in each work task that lead to emission peaks, (iii) identification of emission events that affect the background, thereby leading to far-field exposure risks for workers other than the operator of the work task, and (iv) the fraction of particles emitted from each source that contains CNTs. There is an urgent need for a standardized/harmonized method for electron microscopy (EM) analysis of CNTs. The SEM method developed in this study can form the basis for such a harmonized protocol for the counting of CNTs. The size-resolved DRI techniques are commonly not specific enough to selective analysis of CNT-containing particles and thus cannot yet replace offline time-integrated filter sampling followed by SEM. A combination of EM and DRI techniques offers the most complete characterization of workplace emissions of CNTs today. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.
Rippled beam free electron laser amplifier
Carlsten, Bruce E.
1999-01-01
A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.
Identification of large masses of citrus fruit and rice fields in eastern Spain
NASA Technical Reports Server (NTRS)
Desagredo, F. L.; Salinas, F. G.
1973-01-01
ERTS-1 imagery has been successfully used for the identification of large areas of citrus groves and rice fields in the Valencia region of Eastern Spain. Results are encouraging and will facilitate the elaboration of a land use map with a fair degree of definition once methods prove to be fully operational.
USDA-ARS?s Scientific Manuscript database
It is important to find an appropriate pattern-recognition method for in-field plant identification based on spectral measurement in order to classify the crop and weeds accurately. In this study, the method of Support Vector Machine (SVM) was evaluated and compared with two other methods, Decision ...
Food and forensic molecular identification: update and challenges.
Teletchea, Fabrice; Maudet, Celia; Hänni, Catherine
2005-07-01
The need for accurate and reliable methods for animal species identification has steadily increased during past decades, particularly with the recent food scares and the overall crisis of biodiversity primarily resulting from the huge ongoing illegal traffic of endangered species. A relatively new biotechnological field, known as species molecular identification, based on the amplification and analysis of DNA, offers promising solutions. Indeed, despite the fact that retrieval and analysis of DNA in processed products is a real challenge, numerous technically consistent methods are now available and allow the detection of animal species in almost any organic substrate. However, this field is currently facing a turning point and should rely more on knowledge primarily from three fundamental fields--paleogenetics, molecular evolution and systematics.
ERIC Educational Resources Information Center
Phillips, Sharon A.
2013-01-01
Selecting appropriate performance improvement interventions is a critical component of a comprehensive model of performance improvement. Intervention selection is an interconnected process involving analysis of an organization's environment, definition of the performance problem, and identification of a performance gap and identification of causal…
USDA-ARS?s Scientific Manuscript database
Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the green peach aphid, Myzus persicae, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures t...
USDA-ARS?s Scientific Manuscript database
Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the cotton aphid, Aphis gossypii, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures that ca...
Response of TLD-100 in mixed fields of photons and electrons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lawless, Michael J.; Junell, Stephanie; Hammer, Cliff
Purpose: Thermoluminescent dosimeters (TLDs) are routinely used for dosimetric measurements of high energy photon and electron fields. However, TLD response in combined fields of photon and electron beam qualities has not been characterized. This work investigates the response of TLD-100 (LiF:Mg,Ti) to sequential irradiation by high-energy photon and electron beam qualities. Methods: TLDs were irradiated to a known dose by a linear accelerator with a 6 MV photon beam, a 6 MeV electron beam, and a NIST-traceable {sup 60}Co beam. TLDs were also irradiated in a mixed field of the 6 MeV electron beam and the 6 MV photon beam.more » The average TLD response per unit dose of the TLDs for each linac beam quality was normalized to the average response per unit dose of the TLDs irradiated by the {sup 60}Co beam. Irradiations were performed in water and in a Virtual Water Trade-Mark-Sign phantom. The 6 MV photon beam and 6 MeV electron beam were used to create dose calibration curves relating TLD response to absorbed dose to water, which were applied to the TLDs irradiated in the mixed field. Results: TLD relative response per unit dose in the mixed field was less sensitive than the relative response in the photon field and more sensitive than the relative response in the electron field. Application of the photon dose calibration curve to the TLDs irradiated in a mixed field resulted in an underestimation of the delivered dose, while application of the electron dose calibration curve resulted in an overestimation of the dose. Conclusions: The relative response of TLD-100 in mixed fields fell between the relative response in the photon-only and electron-only fields. TLD-100 dosimetry of mixed fields must account for this intermediate response to minimize the estimation errors associated with calibration factors obtained from a single beam quality.« less
Response of TLD-100 in mixed fields of photons and electrons.
Lawless, Michael J; Junell, Stephanie; Hammer, Cliff; DeWerd, Larry A
2013-01-01
Thermoluminescent dosimeters (TLDs) are routinely used for dosimetric measurements of high energy photon and electron fields. However, TLD response in combined fields of photon and electron beam qualities has not been characterized. This work investigates the response of TLD-100 (LiF:Mg,Ti) to sequential irradiation by high-energy photon and electron beam qualities. TLDs were irradiated to a known dose by a linear accelerator with a 6 MV photon beam, a 6 MeV electron beam, and a NIST-traceable (60)Co beam. TLDs were also irradiated in a mixed field of the 6 MeV electron beam and the 6 MV photon beam. The average TLD response per unit dose of the TLDs for each linac beam quality was normalized to the average response per unit dose of the TLDs irradiated by the (60)Co beam. Irradiations were performed in water and in a Virtual Water™ phantom. The 6 MV photon beam and 6 MeV electron beam were used to create dose calibration curves relating TLD response to absorbed dose to water, which were applied to the TLDs irradiated in the mixed field. TLD relative response per unit dose in the mixed field was less sensitive than the relative response in the photon field and more sensitive than the relative response in the electron field. Application of the photon dose calibration curve to the TLDs irradiated in a mixed field resulted in an underestimation of the delivered dose, while application of the electron dose calibration curve resulted in an overestimation of the dose. The relative response of TLD-100 in mixed fields fell between the relative response in the photon-only and electron-only fields. TLD-100 dosimetry of mixed fields must account for this intermediate response to minimize the estimation errors associated with calibration factors obtained from a single beam quality.
Nanoscale electron manipulation in metals with intense THz electric fields
NASA Astrophysics Data System (ADS)
Takeda, Jun; Yoshioka, Katsumasa; Minami, Yasuo; Katayama, Ikufumi
2018-03-01
Improved control over the electromagnetic properties of metals on a nanoscale is crucial for the development of next-generation nanoelectronics and plasmonic devices. Harnessing the terahertz (THz)-electric-field-induced nonlinearity for the motion of electrons is a promising method of manipulating the local electromagnetic properties of metals, while avoiding undesirable thermal effects and electronic transitions. In this review, we demonstrate the manipulation of electron delocalization in ultrathin gold (Au) films with nanostructures, by intense THz electric-field transients. On increasing the electric-field strength of the THz pulses, the transmittance in the THz-frequency region abruptly decreases around the percolation threshold. The observed THz-electric-field-induced nonlinearity is analysed, based on the Drude-Smith model. The results suggest that ultrafast electron delocalization occurs by electron tunnelling across the narrow insulating bridge between the Au nanostructures, without material breakdown. In order to quantitatively discuss the tunnelling process, we perform scanning tunnelling microscopy with carrier-envelope phase (CEP)-controlled single-cycle THz electric fields. By applying CEP-controlled THz electric fields to the 1 nm nanogap between a metal nanotip and graphite sample, many electrons could be coherently driven through the quantum tunnelling process, either from the nanotip to the sample or vice versa. The presented concept, namely, electron tunnelling mediated by CEP-controlled single-cycle THz electric fields, can facilitate the development of nanoscale electron manipulation, applicable to next-generation ultrafast nanoelectronics and plasmonic devices.
Fast superconducting magnetic field switch
Goren, Yehuda; Mahale, Narayan K.
1996-01-01
The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.
Fast superconducting magnetic field switch
Goren, Y.; Mahale, N.K.
1996-08-06
The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs.
NASA Astrophysics Data System (ADS)
Tattoli, F.; Pierron, F.; Rotinat, R.; Casavola, C.; Pappalettere, C.
2011-01-01
One of the main problems in welding is the microstructural transformation within the area affected by the thermal history. The resulting heterogeneous microstructure within the weld nugget and the heat affected zones is often associated with changes in local material properties. The present work deals with the identification of material parameters governing the elasto—plastic behaviour of the fused and heat affected zones as well as the base material for titanium hybrid welded joints (Ti6Al4V alloy). The material parameters are identified from heterogeneous strain fields with the Virtual Fields Method. This method is based on a relevant use of the principle of virtual work and it has been shown to be useful and much less time consuming than classical finite element model updating approaches applied to similar problems. The paper will present results and discuss the problem of selection of the weld zones for the identification.
Hershkowitz, Noah [Madison, WI; Longmier, Benjamin [Madison, WI; Baalrud, Scott [Madison, WI
2009-03-03
An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.
NASA Technical Reports Server (NTRS)
Hershkowitz, Noah (Inventor); Longmier, Benjamin (Inventor); Baalrud, Scott (Inventor)
2011-01-01
An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.
NASA Technical Reports Server (NTRS)
Hershkowitz, Noah (Inventor); Longmier, Benjamin (Inventor); Baalrud, Scott (Inventor)
2009-01-01
An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.
Designing solution-processable air-stable liquid crystalline crosslinkable semiconductors.
McCulloch, Iain; Bailey, Clare; Genevicius, Kristijonas; Heeney, Martin; Shkunov, Maxim; Sparrowe, David; Tierney, Steven; Zhang, Weimin; Baldwin, Rodney; Kreouzis, Theo; Andreasen, Jens W; Breiby, Dag W; Nielsen, Martin M
2006-10-15
Organic electronics technology, in which at least the semiconducting component of the integrated circuit is an organic material, offers the potential for fabrication of electronic products by low-cost printing technologies, such as ink jet, gravure offset lithography and flexography. The products will typically be of lower performance than those using the present state of the art single crystal or polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal (LC) displays, flexible organic light emitting diode displays, low frequency radio frequency identification tag and other low performance electronics. Organic semiconductors that offer both electrical performance and stability with respect to storage and operation under ambient conditions are required. This work describes the development of reactive mesogen semiconductors, which form large crosslinked LC domains on polymerization within mesophases. These crosslinked domains offer mechanical stability and are inert to solvent exposure in further processing steps. Reactive mesogens containing conjugated aromatic cores, designed to facilitate charge transport and provide good oxidative stability, were prepared and their liquid crystalline properties evaluated. The organization and alignment of the mesogens, both before and after crosslinking, were probed by grazing incidence wide-angle X-ray scattering of thin films. Both time-of-flight and field effect transistor devices were prepared and their electrical characterization reported.
Progress status for the Mu2e calorimeter system
Pezzullo, Gianantonio; Budagov, J.; Carosi, R.; ...
2015-02-13
The Mu2e experiment at FNAL aims to measure the charged-lepton flavor violating neutrinoless conversion of a negative muon into an electron. The conversion results in a monochromatic electron with an energy slightly below the muon rest mass (104.97 MeV). The calorimeter should confirm that the candidates reconstructed by the extremely precise tracker system are indeed conversion electrons while performing a powerfulmore » $$\\mu/e$$ particle identification. Moreover, it should also provide a high level trigger for the experiment independently from the tracker system. The calorimeter should also be able to keep functionality in an environment where the background delivers a dose of ~ 10 krad/year in the hottest area and to work in the presence of 1 T axial magnetic field. These requirements translate in the design of a calorimeter with large acceptance, good energy resolution O(5%) and a reasonable position (time) resolution of ~<1 cm (<0.5ns). The baseline version of the calorimeter is composed by two disks of inner (outer) radius of 351 (660) mm filled by 1860 hexagonal $$BaF_2$$ crystals of 20 cm length. Each crystal is readout by two large area APD's. In this study, we summarize the experimental tests done so far as well as the simulation studies in the Mu2e environment.« less
Smith, Alan D; Flanegin, Frank R
2004-01-01
The concepts of automated e-procurement, or electronic B2B (business-to-business) trade, are grounded in the strategic leveraging of both tangible/intangible assets for successful implementation and execution of electronic trade, resulting in significant financial benefits for firms. Some of the major reasons for this growth include significant process savings from automation, compliance, and purchasing advantage; and reduced costs that organisations can experience by conducting transactions electronically. Although these are the basic benefits associated with generic e-commerce strategies, a majority of these B2B transactions have focused on the purchase of indirect materials (especially office products and travel services). In fact, more than 93% of medical supplies on hospital shelves appear to have universal product numbers on them--at least while still in their boxes and there is a great potential for huge savings in e-procurement in the healthcare field. However, other types of supply chain-related purchases, including maintenance, repair, and operating and replacement parts, and direct material purchases, are becoming more important operational management considerations. In addition, several other key considerations are: existing procurement strategy, the vendor, technology, suppliers, and total costs of ownership. Companies need to analyse their current procurement strategy before developing an e-procurement plan.
Flexible diodes for radio frequency (RF) electronics: a materials perspective
NASA Astrophysics Data System (ADS)
Semple, James; Georgiadou, Dimitra G.; Wyatt-Moon, Gwenhivir; Gelinck, Gerwin; Anthopoulos, Thomas D.
2017-12-01
Over the last decade, there has been increasing interest in transferring the research advances in radiofrequency (RF) rectifiers, the quintessential element of the chip in the RF identification (RFID) tags, obtained on rigid substrates onto plastic (flexible) substrates. The growing demand for flexible RFID tags, wireless communications applications and wireless energy harvesting systems that can be produced at a low-cost is a key driver for this technology push. In this topical review, we summarise recent progress and status of flexible RF diodes and rectifying circuits, with specific focus on materials and device processing aspects. To this end, different families of materials (e.g. flexible silicon, metal oxides, organic and carbon nanomaterials), manufacturing processes (e.g. vacuum and solution processing) and device architectures (diodes and transistors) are compared. Although emphasis is placed on performance, functionality, mechanical flexibility and operating stability, the various bottlenecks associated with each technology are also addressed. Finally, we present our outlook on the commercialisation potential and on the positioning of each material class in the RF electronics landscape based on the findings summarised herein. It is beyond doubt that the field of flexible high and ultra-high frequency rectifiers and electronics as a whole will continue to be an active area of research over the coming years.
The Electron Drift Technique for Measuring Electric and Magnetic Fields
NASA Technical Reports Server (NTRS)
Paschmann, G.; McIlwain, C. E.; Quinn, J. M.; Torbert, R. B.; Whipple, E. C.; Christensen, John (Technical Monitor)
1998-01-01
The electron drift technique is based on sensing the drift of a weak beam of test electrons that is caused by electric fields and/or gradients in the magnetic field. These quantities can, by use of different electron energies, in principle be determined separately. Depending on the ratio of drift speed to magnetic field strength, the drift velocity can be determined either from the two emission directions that cause the electrons to gyrate back to detectors placed some distance from the emitting guns, or from measurements of the time of flight of the electrons. As a by-product of the time-of-flight measurements, the magnetic field strength is also determined. The paper describes strengths and weaknesses of the method as well as technical constraints.
Electron heating and acceleration during magnetic reconnection
NASA Astrophysics Data System (ADS)
Dahlin, Joel
2017-10-01
Magnetic reconnection is thought to be an important driver of energetic particles in a variety of astrophysical phenomena such as solar flares and magnetospheric storms. However, the observed fraction of energy imparted to a nonthermal component can vary widely in different regimes. We use kinetic particle-in-cell (PIC) simulations to demonstrate the important role of the non-reversing (guide) field in controlling the efficiency of electron acceleration in collisionless reconnection. In reconnection where the guide field is smaller than the reconnecting component, the dominant electron accelerator is a Fermi-type mechanism that preferentially energizes the most energetic particles. In strong guide field reconnection, the field-line contraction that drives the Fermi mechanism becomes weak. Instead, parallel electric fields are primarily responsible for driving electron heating but are ineffective in driving the energetic component of the spectrum. Three-dimensional simulations reveal that the stochastic magnetic field that develops during 3D guide field reconnection plays a vital role in particle acceleration and transport. The reconnection outflows that drive Fermi acceleration also expel accelerating particles from energization regions. In 2D reconnection, electrons are trapped in island cores and acceleration ceases, whereas in 3D the stochastic magnetic field enables energetic electrons to leak out of islands and freely sample regions of energy release. A finite guide field is required to break initial 2D symmetry and facilitate escape from island structures. We show that reconnection with a guide field comparable to the reconnecting field generates the greatest number of energetic electrons, a regime where both (a) the Fermi mechanism is an efficient driver and (b) energetic electrons may freely access acceleration sites. These results have important implications for electron acceleration in solar flares and reconnection-driven dissipation in turbulence.
O'Mahony, Aoife M; Samek, Izabela A; Sattayasamitsathit, Sirilak; Wang, Joseph
2014-08-19
Field-deployable voltammetric screening coupled with complementary laboratory-based analysis to confirm the presence of gunshot residue (GSR) from the hands of a subject who has handled, loaded, or discharged a firearm is described. This protocol implements the orthogonal identification of the presence of GSR utilizing square-wave stripping voltammetry (SWSV) as a rapid screening tool along with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to confirm the presence of the characteristic morphology and metal composition of GSR particles. This is achieved through the judicious modification of the working electrode of a carbon screen-printed electrode (CSPE) with carbon tape (used in SEM analysis) to fix and retain a sample. A comparison between a subject who has handled and loaded a firearm and a subject who has had no contact with GSR shows the significant variations in voltammetric signals and the presence or absence of GSR-consistent particles and constituent metals. This initial electrochemical screening has no effect on the integrity of the metallic particles, and SEM/EDX analysis conducted prior to and postvoltammetry show no differences in analytical output. The carbon tape is instrumental in retaining the GSR sample after electrochemical analysis, supported by comparison with orthogonal detection at a bare CSPE. This protocol shows great promise as a two-tier detection system for the presence of GSR from the hands of a subject, whereby initial screening can be conducted rapidly onsite by minimally trained operators; confirmation can follow at the same substrate to substantiate the voltammetric results.
Kuipers, Jeroen; van Ham, Tjakko J; Kalicharan, Ruby D; Veenstra-Algra, Anneke; Sjollema, Klaas A; Dijk, Freark; Schnell, Ulrike; Giepmans, Ben N G
2015-04-01
Ultrastructural examination of cells and tissues by electron microscopy (EM) yields detailed information on subcellular structures. However, EM is typically restricted to small fields of view at high magnification; this makes quantifying events in multiple large-area sample sections extremely difficult. Even when combining light microscopy (LM) with EM (correlated LM and EM: CLEM) to find areas of interest, the labeling of molecules is still a challenge. We present a new genetically encoded probe for CLEM, named "FLIPPER", which facilitates quantitative analysis of ultrastructural features in cells. FLIPPER consists of a fluorescent protein (cyan, green, orange, or red) for LM visualization, fused to a peroxidase allowing visualization of targets at the EM level. The use of FLIPPER is straightforward and because the module is completely genetically encoded, cells can be optimally prepared for EM examination. We use FLIPPER to quantify cellular morphology at the EM level in cells expressing a normal and disease-causing point-mutant cell-surface protein called EpCAM (epithelial cell adhesion molecule). The mutant protein is retained in the endoplasmic reticulum (ER) and could therefore alter ER function and morphology. To reveal possible ER alterations, cells were co-transfected with color-coded full-length or mutant EpCAM and a FLIPPER targeted to the ER. CLEM examination of the mixed cell population allowed color-based cell identification, followed by an unbiased quantitative analysis of the ER ultrastructure by EM. Thus, FLIPPER combines bright fluorescent proteins optimized for live imaging with high sensitivity for EM labeling, thereby representing a promising tool for CLEM.
Field emission electron source
Zettl, Alexander Karlwalter; Cohen, Marvin Lou
2000-01-01
A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.
NASA Astrophysics Data System (ADS)
Lu, Xianfeng
The focus of this thesis is the study of the field electron emission (FEE) of diamond and related films synthesized by plasma enhanced chemical vapor deposition. The diamond and related films with different morphologies and compositions were prepared in a microwave plasma-enhanced chemical vapor deposition (CVD) reactor and a hot filament CVD reactor. Various analytical techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy were employed to characterize the surface morphology and chemical composition. The influence of surface morphology on the field electron emission property of diamond films was studied. The emission current of well-oriented microcrystalline diamond films is relatively small compared to that of randomly oriented microcrystalline diamond films. Meanwhile, the nanocrystalline diamond film has demonstrated a larger emission current than microcrystalline diamond films. The nanocone structure significantly improves the electron emission current of diamond films due to its strong field enhancement effect. The sp2 phase concentration also has significant influence on the field electron emission property of diamond films. For the diamond films synthesized by gas mixture of hydrogen and methane, their field electron emission properties were enhanced with the increase of methane concentration. The field electron emission enhancement was attributed to the increase of sp2 phase concentration, which increases the electrical conductivity of diamond films. For the diamond films synthesized through graphite etching, the growth rate and nucleation density of diamond films increase significantly with decreasing hydrogen flow rate. The field electron emission properties of the diamond films were also enhanced with the decrease of hydrogen flow rate. The field electron emission enhancement can be also attributed to the increase of the sp 2 phase concentration. In addition, the deviation of the experimental Fowler-Nordheim (F-N) plot from a straight line was observed for graphitic nanocone films. The deviation can be mainly attributed to the nonuniform field enhancement factor of the graphitic nanocones. In low macroscopic electric field regions, electrons are emitted mainly from nanocone or nanocones with the largest field enhancement factor, which corresponds to the smallest slope magnitude. With the increase of electric field, nanocones with small field enhancement factors also contribute to the emission current, which results in a reduced average field enhancement factor and therefore a large slope magnitude.
Method of synthesizing small-diameter carbon nanotubes with electron field emission properties
NASA Technical Reports Server (NTRS)
Liu, Jie (Inventor); Du, Chunsheng (Inventor); Qian, Cheng (Inventor); Gao, Bo (Inventor); Qiu, Qi (Inventor); Zhou, Otto Z. (Inventor)
2009-01-01
Carbon nanotube material having an outer diameter less than 10 nm and a number of walls less than ten are disclosed. Also disclosed are an electron field emission device including a substrate, an optionally layer of adhesion-promoting layer, and a layer of electron field emission material. The electron field emission material includes a carbon nanotube having a number of concentric graphene shells per tube of from two to ten, an outer diameter from 2 to 8 nm, and a nanotube length greater than 0.1 microns. One method to fabricate carbon nanotubes includes the steps of (a) producing a catalyst containing Fe and Mo supported on MgO powder, (b) using a mixture of hydrogen and carbon containing gas as precursors, and (c) heating the catalyst to a temperature above 950.degree. C. to produce a carbon nanotube. Another method of fabricating an electron field emission cathode includes the steps of (a) synthesizing electron field emission materials containing carbon nanotubes with a number of concentric graphene shells per tube from two to ten, an outer diameter of from 2 to 8 nm, and a length greater than 0.1 microns, (b) dispersing the electron field emission material in a suitable solvent, (c) depositing the electron field emission materials onto a substrate, and (d) annealing the substrate.
Microscale Digital Vacuum Electronic Gates
NASA Technical Reports Server (NTRS)
Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)
2014-01-01
Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.
NASA Technical Reports Server (NTRS)
Eriksson, S.; Wilder, F. D.; Ergun, R. E.; Schwartz, S. J.; Cassak, P. A.; Burch, J. L.; Chen, Li-Jen; Torbert, R. B.; Phan, T. D.; Lavraud, B.;
2016-01-01
We report observations from the Magnetospheric Multiscale (MMS) satellites of a large guide field magnetic reconnection event. The observations suggest that two of the four MMS spacecraft sampled the electron diffusion region, whereas the other two spacecraft detected the exhaust jet from the event. The guide magnetic field amplitude is approximately 4 times that of the reconnecting field. The event is accompanied by a significant parallel electric field (E(sub parallel lines) that is larger than predicted by simulations. The high-speed (approximately 300 km/s) crossing of the electron diffusion region limited the data set to one complete electron distribution inside of the electron diffusion region, which shows significant parallel heating. The data suggest that E(sub parallel lines) is balanced by a combination of electron inertia and a parallel gradient of the gyrotropic electron pressure.
NASA Astrophysics Data System (ADS)
Karpov, S. Y.; Zakheim, D. A.; Lundin, W. V.; Sakharov, A. V.; Zavarin, E. E.; Brunkov, P. N.; Lundina, E. Y.; Tsatsulnikov, A. F.
2018-02-01
In situ growth of an ultra-thin (up to 2.5 nm) Si3N4 film on the top of n-GaN is shown to reduce remarkably the height of the barrier formed by deposition of Ni-based Schottky contact. The reduction is interpreted in terms of polarization dipole induced at the Si3N4/n-GaN interface and Fermi level pinning at the Ni/Si3N4 interface. Detailed study of temperature-dependent current-voltage characteristics enables identification of the electron transport mechanism in such Schottky diodes under forward bias: thermal/field electron emission over the barrier formed in n-GaN followed by tunneling through the Si3N4 film. At reverse bias and room temperature, the charge transfer is likely controlled by Poole-Frenkel ionization of deep traps in n-GaN. Tunneling exponents at forward and reverse biases and the height of the Ni/Si3N4 Schottky barrier are evaluated experimentally and compared with theoretical predictions.
NASA Astrophysics Data System (ADS)
Mao, Gaojun; Cao, Rui; Guo, Xili; Jiang, Yong; Chen, Jianhong
2017-12-01
The kinetic processes of nucleation and growth of bainite laths in reheated weld metals are observed and analyzed by a combination of a laser confocal scanning microscope and an electron backscattering diffraction with a field emission scanning electron microscope. The results indicate that the surface relief induced by phase transformation is able to reveal the real microstructural morphologies of bainite laths when viewed from various angles. Five nucleation modes and six types of growth behaviors of bainite laths are revealed. The bainite lath growth rates are measured to vary over a wide range, from 2 μm/s to higher than 2000 μm/s. The orientations of the bainite laths within a prior austenite grain are examined and denoted as different variants. On the basis of variant identification, the reason is analyzed for various growth rates which are demonstrated to be affected by (1) the density of the high-angle misorientation in it, (2) the included angle between habit planes of different variants, and (3) the direction of lath growth with respect to the free (polished) surface.
Fractal Complexity-Based Feature Extraction Algorithm of Communication Signals
NASA Astrophysics Data System (ADS)
Wang, Hui; Li, Jingchao; Guo, Lili; Dou, Zheng; Lin, Yun; Zhou, Ruolin
How to analyze and identify the characteristics of radiation sources and estimate the threat level by means of detecting, intercepting and locating has been the central issue of electronic support in the electronic warfare, and communication signal recognition is one of the key points to solve this issue. Aiming at accurately extracting the individual characteristics of the radiation source for the increasingly complex communication electromagnetic environment, a novel feature extraction algorithm for individual characteristics of the communication radiation source based on the fractal complexity of the signal is proposed. According to the complexity of the received signal and the situation of environmental noise, use the fractal dimension characteristics of different complexity to depict the subtle characteristics of the signal to establish the characteristic database, and then identify different broadcasting station by gray relation theory system. The simulation results demonstrate that the algorithm can achieve recognition rate of 94% even in the environment with SNR of -10dB, and this provides an important theoretical basis for the accurate identification of the subtle features of the signal at low SNR in the field of information confrontation.
NASA Astrophysics Data System (ADS)
Abdu, M. A.; Nogueira, P. A. B.; Souza, J. R.; Batista, I. S.; Dutra, S. L. G.; Sobral, J. H. A.
2017-03-01
Large enhancement in the equatorial electrojet (EEJ) current can occur due to sudden increase in the E layer density arising from solar flare associated ionizing radiations, as also from background electric fields modified by magnetospheric disturbances when present before or during a solar flare. We investigate the EEJ responses at widely separated longitudes during two X-class flares that occurred at different activity phases surrounding the magnetic super storm sequences of 28-29 October 2003. During the 28 October flare we observed intense reverse electrojet under strong westward electric field in the sunrise sector over Jicamarca. Sources of westward disturbance electric fields driving large EEJ current are identified for the first time. Model calculations on the E layer density, with and without flare, and comparison of the results between Jicamarca and Sao Luis suggested enhanced westward electric field due to the flare occurring close to sunrise (over Jicamarca). During the flare on 29 October, which occurred during a rapid AE recovery, a strong overshielding electric field of westward polarity over Jicamarca delayed an expected EEJ eastward growth due to flare-induced ionization enhancement in the afternoon. This EEJ response yielded a measure of the overshielding decay time determined by the storm time Region 2 field-aligned current. This paper will present a detailed analysis of the EEJ responses during the two flares, including a quantitative evaluation of the flare-induced electron density enhancements and identification of electric field sources that played dominant roles in the large westward EEJ at the sunrise sector over Jicamarca.
Light-field-driven currents in graphene
NASA Astrophysics Data System (ADS)
Higuchi, Takuya; Heide, Christian; Ullmann, Konrad; Weber, Heiko B.; Hommelhoff, Peter
2017-10-01
The ability to steer electrons using the strong electromagnetic field of light has opened up the possibility of controlling electron dynamics on the sub-femtosecond (less than 10-15 seconds) timescale. In dielectrics and semiconductors, various light-field-driven effects have been explored, including high-harmonic generation, sub-optical-cycle interband population transfer and the non-perturbative change of the transient polarizability. In contrast, much less is known about light-field-driven electron dynamics in narrow-bandgap systems or in conductors, in which screening due to free carriers or light absorption hinders the application of strong optical fields. Graphene is a promising platform with which to achieve light-field-driven control of electrons in a conducting material, because of its broadband and ultrafast optical response, weak screening and high damage threshold. Here we show that a current induced in monolayer graphene by two-cycle laser pulses is sensitive to the electric-field waveform, that is, to the exact shape of the optical carrier field of the pulse, which is controlled by the carrier-envelope phase, with a precision on the attosecond (10-18 seconds) timescale. Such a current, dependent on the carrier-envelope phase, shows a striking reversal of the direction of the current as a function of the driving field amplitude at about two volts per nanometre. This reversal indicates a transition of light-matter interaction from the weak-field (photon-driven) regime to the strong-field (light-field-driven) regime, where the intraband dynamics influence interband transitions. We show that in this strong-field regime the electron dynamics are governed by sub-optical-cycle Landau-Zener-Stückelberg interference, composed of coherent repeated Landau-Zener transitions on the femtosecond timescale. Furthermore, the influence of this sub-optical-cycle interference can be controlled with the laser polarization state. These coherent electron dynamics in graphene take place on a hitherto unexplored timescale, faster than electron-electron scattering (tens of femtoseconds) and electron-phonon scattering (hundreds of femtoseconds). We expect these results to have direct ramifications for band-structure tomography and light-field-driven petahertz electronics.
Light-field-driven currents in graphene.
Higuchi, Takuya; Heide, Christian; Ullmann, Konrad; Weber, Heiko B; Hommelhoff, Peter
2017-10-12
The ability to steer electrons using the strong electromagnetic field of light has opened up the possibility of controlling electron dynamics on the sub-femtosecond (less than 10 -15 seconds) timescale. In dielectrics and semiconductors, various light-field-driven effects have been explored, including high-harmonic generation, sub-optical-cycle interband population transfer and the non-perturbative change of the transient polarizability. In contrast, much less is known about light-field-driven electron dynamics in narrow-bandgap systems or in conductors, in which screening due to free carriers or light absorption hinders the application of strong optical fields. Graphene is a promising platform with which to achieve light-field-driven control of electrons in a conducting material, because of its broadband and ultrafast optical response, weak screening and high damage threshold. Here we show that a current induced in monolayer graphene by two-cycle laser pulses is sensitive to the electric-field waveform, that is, to the exact shape of the optical carrier field of the pulse, which is controlled by the carrier-envelope phase, with a precision on the attosecond (10 -18 seconds) timescale. Such a current, dependent on the carrier-envelope phase, shows a striking reversal of the direction of the current as a function of the driving field amplitude at about two volts per nanometre. This reversal indicates a transition of light-matter interaction from the weak-field (photon-driven) regime to the strong-field (light-field-driven) regime, where the intraband dynamics influence interband transitions. We show that in this strong-field regime the electron dynamics are governed by sub-optical-cycle Landau-Zener-Stückelberg interference, composed of coherent repeated Landau-Zener transitions on the femtosecond timescale. Furthermore, the influence of this sub-optical-cycle interference can be controlled with the laser polarization state. These coherent electron dynamics in graphene take place on a hitherto unexplored timescale, faster than electron-electron scattering (tens of femtoseconds) and electron-phonon scattering (hundreds of femtoseconds). We expect these results to have direct ramifications for band-structure tomography and light-field-driven petahertz electronics.
Salvatore, Giovanni A; Münzenrieder, Niko; Barraud, Clément; Petti, Luisa; Zysset, Christoph; Büthe, Lars; Ensslin, Klaus; Tröster, Gerhard
2013-10-22
Recently, transition metal dichalcogenides (TMDCs) have attracted interest thanks to their large field effective mobility (>100 cm(2)/V · s), sizable band gap (around 1-2 eV), and mechanical properties, which make them suitable for high performance and flexible electronics. In this paper, we present a process scheme enabling the fabrication and transfer of few-layers MoS2 thin film transistors from a silicon template to any arbitrary organic or inorganic and flexible or rigid substrate or support. The two-dimensional semiconductor is mechanically exfoliated from a bulk crystal on a silicon/polyvinyl alcohol (PVA)/polymethyl methacrylane (PMMA) stack optimized to ensure high contrast for the identification of subnanometer thick flakes. Thin film transistors (TFTs) with structured source/drain and gate electrodes are fabricated following a designed procedure including steps of UV lithography, wet etching, and atomic layer deposited (ALD) dielectric. Successively, after the dissolution of the PVA sacrificial layer in water, the PMMA film, with the devices on top, can be transferred to another substrate of choice. Here, we transferred the devices on a polyimide plastic foil and studied the performance when tensile strain is applied parallel to the TFT channel. We measured an electron field effective mobility of 19 cm(2)/(V s), an I(on)/I(off)ratio greater than 10(6), a gate leakage current as low as 0.3 pA/μm, and a subthreshold swing of about 250 mV/dec. The devices continue to work when bent to a radius of 5 mm and after 10 consecutive bending cycles. The proposed fabrication strategy can be extended to any kind of 2D materials and enable the realization of electronic circuits and optical devices easily transferrable to any other support.
Fox, W.; Sciortino, F.; v. Stechow, A.; ...
2017-03-21
We report detailed laboratory observations of the structure of a reconnection current sheet in a two-fluid plasma regime with a guide magnetic field. We observe and quantitatively analyze the quadrupolar electron pressure variation in the ion-diffusion region, as originally predicted by extended magnetohydrodynamics simulations. The projection of the electron pressure gradient parallel to the magnetic field contributes significantly to balancing the parallel electric field, and the resulting cross-field electron jets in the reconnection layer are diamagnetic in origin. Furthermore, these results demonstrate how parallel and perpendicular force balance are coupled in guide field reconnection and confirm basic theoretical models ofmore » the importance of electron pressure gradients for obtaining fast magnetic reconnection.« less
NASA Astrophysics Data System (ADS)
Qiao, Bin; He, X. T.; Zhu, Shao-ping; Zheng, C. Y.
2005-08-01
The acceleration of plasma electron in intense laser-plasma interaction is investigated analytically and numerically, where the conjunct effect of laser fields and self-consistent spontaneous fields (including quasistatic electric field Esl, azimuthal quasistatic magnetic field Bsθ and the axial one Bsz) is completely considered for the first time. An analytical relativistic electron fluid model using test-particle method has been developed to give an explicit analysis about the effects of each quasistatic fields. The ponderomotive accelerating and scattering effects on electrons are partly offset by Esl, furthermore, Bsθ pinches and Bsz collimates electrons along the laser axis. The dependences of energy gain and scattering angle of electron on its initial radial position, plasma density, and laser intensity are, respectively, studied. The qualities of the relativistic electron beam (REB), such as energy spread, beam divergence, and emitting (scattering) angle, generated by both circularly polarized (CP) and linearly polarized (LP) lasers are studied. Results show CP laser is of clear advantage comparing to LP laser for it can generate a better REB in collimation and stabilization.
Identification of Rays through DNA Barcoding: An Application for Ecologists
Cerutti-Pereyra, Florencia; Meekan, Mark G.; Wei, Nu-Wei V.; O'Shea, Owen; Bradshaw, Corey J. A.; Austin, Chris M.
2012-01-01
DNA barcoding potentially offers scientists who are not expert taxonomists a powerful tool to support the accuracy of field studies involving taxa that are diverse and difficult to identify. The taxonomy of rays has received reasonable attention in Australia, although the fauna in remote locations such as Ningaloo Reef, Western Australia is poorly studied and the identification of some species in the field is problematic. Here, we report an application of DNA-barcoding to the identification of 16 species (from 10 genera) of tropical rays as part of an ecological study. Analysis of the dataset combined across all samples grouped sequences into clearly defined operational taxonomic units, with two conspicuous exceptions: the Neotrygon kuhlii species complex and the Aetobatus species complex. In the field, the group that presented the most difficulties for identification was the spotted whiptail rays, referred to as the ‘uarnak’ complex. Two sets of problems limited the successful application of DNA barcoding: (1) the presence of cryptic species, species complexes with unresolved taxonomic status and intra-specific geographical variation, and (2) insufficient numbers of entries in online databases that have been verified taxonomically, and the presence of lodged sequences in databases with inconsistent names. Nevertheless, we demonstrate the potential of the DNA barcoding approach to confirm field identifications and to highlight species complexes where taxonomic uncertainty might confound ecological data. PMID:22701556
Non Fermi Liquid Crossovers in a Quasi-One-Dimensional Conductor in an Inclined Magnetic Field
NASA Astrophysics Data System (ADS)
Lebed, Andrei
We consider a theoretical problem of electron-electron scattering time in a quasi-one-dimensional (Q1D) conductor in a magnetic field, perpendicular to its conducting axis. We show that inverse electron-electron scattering time becomes of the order of characteristic electron energy, 1 / τ ~ ɛ ~ T , in a high magnetic field, directed far from the main crystallographic axes, which indicates breakdown of the Fermi liquid theory. In a magnetic field, directed close to one of the main crystallographic axis, inverse electron-electron scattering time becomes much smaller than characteristic electron energy and, thus, applicability of Fermi liquid theory restores. We suggest that there exist crossovers between Fermi liquid and some non Fermi liquid states in a strong enough inclined magnetic field. Application of our results to the Q1D conductor (Per)2Au(mnt)2 shows that it has to be possible to observe the above mentioned phenomenon in feasibly high magnetic fields of the order of H >=H* ~= 25 T . It was partially supported by NFS grant DMR-1104512.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Akou, H., E-mail: h.akou@nit.ac.ir; Hamedi, M.
2015-10-15
In this paper, the generation of high-quality and high-energy micro electron beam in vacuum by a chirped Gaussian laser pulse in the presence of an axial magnetic field is numerically investigated. The features of energy and angular spectra, emittances, and position distribution of electron beam are compared in two cases, i.e., in the presence and absence of an external magnetic field. The electron beam is accelerated with higher energy and qualified in spatial distribution in the presence of the magnetic field. The presence of an axial magnetic field improves electron beam spatial quality as well as its gained energy throughmore » keeping the electron motion parallel to the direction of propagation for longer distances. It has been found that a 64 μm electron bunch with about MeV initial energy becomes a 20 μm electron beam with high energy of the order of GeV, after interacting with a laser pulse in the presence of an external magnetic field.« less
Optical properties of the magnetic monopole field applied to electron microscopy and spectroscopy
NASA Astrophysics Data System (ADS)
Kruit, P.; Lenc, M.
1992-11-01
An analytical treatment of the electron's motion in a magnetic monopole field results in useful expressions for both the lens action and the mirror action of the field. Using an appropriate definition of the magnetic moment of the electron, it is shown that there is an exact conservation of this parameter in the monopole field, implying that the motion is perfectly adiabatic. This property is important when the field is used for directing Auger electrons from a target to a detector; that is, when it is used as a parallelizer in a through-the-lens detection scheme. Regarding the monopole field as an electron lens, the image position and magnification are derived for an arbitrary object position. Expressions for both the axial aberrations (chromatic and spherical) and the image aberrations (coma, field curvature, astigmatism, distortion, and transverse chromatic) are derived for an arbitrary number of intermediate images between object and final image. The chromatic aberration turns out to be independent of the number of intermediate images and the spherical aberration decreases slightly with this number. This property is important when an electron beam must be focused to a small probe in a strong magnetic field. It is shown that if a certain combination of deflectors is used in conjunction with the monopole field, an ideal swinging objective lens is obtained: All image aberrations except field curvature disappear. Designs are presented in which the monopole field is used in the objective lenses of a transmission electron microscope and a scanning electron microscope.
A scoring scheme for evaluating magnetofossil identifications
NASA Astrophysics Data System (ADS)
Kopp, R. E.; Kirschvink, J. L.
2007-12-01
In many Quaternary lacustrine and marine settings, fossil magnetotactic bacteria are a major contributor to sedimentary magnetization [1]. Magnetite particles produced by magnetotactic bacteria have traits, shaped by natural selection, that increase the efficiency with which the bacteria utilize iron and also facilitate the recognition of the particles' biological origin. In particular, magnetotactic bacteria generally produce particles with characteristic shapes and narrow size and shape distributions that lie within the single domain stability field. The particles have effective positive magnetic anisotropy, produced by alignment in chains and frequently by particle elongation. In addition, the crystals are often nearly stochiometric and have few crystallographic defects. Yet, despite these distinctive traits, there are few identified magnetofossils that predate the Quaternary, and many putative identifications are highly controversial. We propose a six-criteria scoring scheme for evaluating identifications based on the quality of the geological, magnetic, and electron microscopic evidence. Our criteria are: (1) whether the geological context is well-constrained stratigraphically, and whether paleomagnetic evidence suggests a primary magnetization; (2) whether magnetic or microscopic evidence support the presence of significant single-domain magnetite; (3) whether magnetic or ferromagnetic resonance evidence indicates narrow size and shape distributions, and whether microscopic evidence reveals single-domain particles with truncated edges, elongate single-domain particles, and/or narrow size and shape distributions; (4) whether ferromagnetic resonance, low-temperature magnetic, or electron microscopic evidence reveals the presence of chains; (5) whether low-temperature magnetometry, energy dispersive X-ray spectroscopy, or other techniques demonstrate the near-stochiometry of the particles; and (6) whether high-resolution TEM indicates the near- absence of crystallographic defects. We use criterion 1 to set the threshold for determining whether a magnetofossil identification is robust. Criteria 3 and 4 are assigned numerical scores that range from 0 to 4, while criteria 2, 5, and 6 are evaluated based on presence or absence. Based on this scheme, the oldest robust magnetofossils yet found come from the Cretaceous chalk beds of southern England [2], though Lower Cambrian limestones of the Pestrotsvet Formation, Siberia Platform, only marginally fail to meet our robust criteria [3]. Although magnetofossils have also been reported from Proterozoic, Archean, and Martian rocks, none of these identifications are robust. References: [1] R. E. Kopp and J. L. Kirschvink (2007). Earth Sci. Rev. doi:10.1016/j.earscirev.2007.08.001. [2] P. Montgomery et al. (1998). Earth Planet. Sci. Lett. 156: 209-224. [3] S. B. R. Chang et al. (1987). Phys. Earth Planet. Int. 46: 289-303.
Photon - electron identification in the PHENIX Electromagnetic Calorimeter
NASA Astrophysics Data System (ADS)
Edouard, Kistenev; Gabor, David; Sebastian, White; Craig, Woody; Alexander, Bazilevsky; Vladimir, Kochetkov; Valeriy, Onuchin
1998-10-01
The results on the electron/hadron descrimination based upon analysis of the data collected from PHENIX electromagnetic calorimeter are presented. Two configurations are considered: (a) stand alone calorimeter; (b) calorimeter assisted by tracking devices to provide an independent estimates for particle momenta.
45 CFR 164.312 - Technical safeguards.
Code of Federal Regulations, 2012 CFR
2012-10-01
... REQUIREMENTS SECURITY AND PRIVACY Security Standards for the Protection of Electronic Protected Health... that maintain electronic protected health information to allow access only to those persons or software... specifications: (i) Unique user identification (Required). Assign a unique name and/or number for identifying and...
An IT-enabled supply chain model: a simulation study
NASA Astrophysics Data System (ADS)
Cannella, Salvatore; Framinan, Jose M.; Barbosa-Póvoa, Ana
2014-11-01
During the last decades, supply chain collaboration practices and the underlying enabling technologies have evolved from the classical electronic data interchange (EDI) approach to a web-based and radio frequency identification (RFID)-enabled collaboration. In this field, most of the literature has focused on the study of optimal parameters for reducing the total cost of suppliers, by adopting operational research (OR) techniques. Herein we are interested in showing that the considered information technology (IT)-enabled structure is resilient, that is, it works well across a reasonably broad range of parameter settings. By adopting a methodological approach based on system dynamics, we study a multi-tier collaborative supply chain. Results show that the IT-enabled supply chain improves operational performance and customer service level. Nonetheless, benefits for geographically dispersed networks are of minor entity.
On-wafer, cryogenic characterization of ultra-low noise HEMT devices
NASA Technical Reports Server (NTRS)
Bautista, J. J.; Laskar, J.; Szydlik, P.
1995-01-01
Significant advances in the development of high electron-mobility field-effect transistors (HEMT's) have resulted in cryogenic, low-noise amplifiers (LNA's) whose noise temperatures are within an order of magnitude of the quantum noise limit (hf/k). Further advances in HEMT technology at cryogenic temperatures may eventually lead to the replacement of maser and superconducting insulator superconducting front ends in the 1- to 100-GHz frequency band. Key to identification of the best HEMT's and optimization of cryogenic LNA's are accurate and repeatable device measurements at cryogenic temperatures. This article describes the design and operation of a cryogenic coplanar waveguide probe system for the characterization and modeling of advanced semiconductor transistors at cryogenic temperatures. Results on advanced HEMT devices are presented to illustrate the utility of the measurement system.
Towards Prognostics of Power MOSFETs: Accelerated Aging and Precursors of Failure
NASA Technical Reports Server (NTRS)
Celaya, Jose R.; Saxena, Abhinav; Wysocki, Philip; Saha, Sankalita; Goebel, Kai
2010-01-01
This paper presents research results dealing with power MOSFETs (metal oxide semiconductor field effect transistor) within the prognostics and health management of electronics. Experimental results are presented for the identification of the on-resistance as a precursor to failure of devices with die-attach degradation as a failure mechanism. Devices are aged under power cycling in order to trigger die-attach damage. In situ measurements of key electrical and thermal parameters are collected throughout the aging process and further used for analysis and computation of the on-resistance parameter. Experimental results show that the devices experience die-attach damage and that the on-resistance captures the degradation process in such a way that it could be used for the development of prognostics algorithms (data-driven or physics-based).
NASA Astrophysics Data System (ADS)
Bordes, Roy N.
1998-12-01
The purpose of this presentation is to enlighten the reader on the advancements that have been made in the field of biometrics technology as it relates to government and industrial-type applications. The term 'biometrics' is defined as, 'Any technology that uses electronically scanned graphical information for identification purposes.' Biometric technology was for a long time in the experimental stages, with many BETA test projects that were really not applicable to industrial markets. During the course of this presentation, we will show that biometrics applications do work, can develop positive returns on investment, but from a security standpoint have some major application problems that still need to be overcome. We will also address which biometric technologies have a better future in the security world than others.
Fonseca, Michelle Cristie Gonçalves da; Knoff, Marcelo; Felizardo, Nilza Nunes; Di Azevedo, Maria Isabel N; Torres, Eduardo José Lopes; Gomes, Delir Corrêa; Iñiguez, Alena Mayo; São Clemente, Sérgio Carmona de
2016-10-17
Thirty-six Paralichthys patagonicus and 30 Xystreurys rasile were collected in the state of Rio de Janeiro, Brazil to investigate the presence of anisakid and raphidascaridid nematodes. Anisakis typica, Terranova sp., Contracaecum sp., Hysterothylacium deardorffoverstreetorum, and Raphidascaris sp. were identified using integrative taxonomy of morphological and genetic data. Morphological and morphometric analysis was conducted using bright field microscopy with scanning electron microscopy for topographic characterization of the cuticular surface. Phylogenetic analysis, using ITS and cox2 molecular targets, clearly demonstrated the species identification of A. typica and H. deardorffoverstreetorum and the high diversity of H. deardorffoverstreetorum. This is the first report of A. typica, H. deardorffoverstreetorum, and Raphidascaris sp. parasitizing P. patagonicus and X. rasile. Copyright © 2016 Elsevier B.V. All rights reserved.
Simulations of Dynamical Friction Including Spatially-Varying Magnetic Fields
NASA Astrophysics Data System (ADS)
Bell, G. I.; Bruhwiler, D. L.; Litvinenko, V. N.; Busby, R.; Abell, D. T.; Messmer, P.; Veitzer, S.; Cary, J. R.
2006-03-01
A proposed luminosity upgrade to the Relativistic Heavy Ion Collider (RHIC) includes a novel electron cooling section, which would use ˜55 MeV electrons to cool fully-ionized 100 GeV/nucleon gold ions. We consider the dynamical friction force exerted on individual ions due to a relevant electron distribution. The electrons may be focussed by a strong solenoid field, with sensitive dependence on errors, or by a wiggler field. In the rest frame of the relativistic co-propagating electron and ion beams, where the friction force can be simulated for nonrelativistic motion and electrostatic fields, the Lorentz transform of these spatially-varying magnetic fields includes strong, rapidly-varying electric fields. Previous friction force simulations for unmagnetized electrons or error-free solenoids used a 4th-order Hermite algorithm, which is not well-suited for the inclusion of strong, rapidly-varying external fields. We present here a new algorithm for friction force simulations, using an exact two-body collision model to accurately resolve close interactions between electron/ion pairs. This field-free binary-collision model is combined with a modified Boris push, using an operator-splitting approach, to include the effects of external fields. The algorithm has been implemented in the VORPAL code and successfully benchmarked.
Chaffin, R.J.; Dawson, L.R.; Fritz, I.J.; Osbourn, G.C.; Zipperian, T.E.
1984-04-19
In a field-effect transistor comprising a semiconductor having therein a source, a drain, a channel and a gate in operational relationship, there is provided an improvement wherein said semiconductor is a superlattice comprising alternating quantum well and barrier layers, the quantum well layers comprising a first direct gap semiconductor material which in bulk form has a certain bandgap and a curve of electron velocity versus applied electric field which has a maximum electron velocity at a certain electric field, the barrier layers comprising a second semiconductor material having a bandgap wider than that of said first semiconductor material, wherein the layer thicknesses of said quantum well and barrier layers are sufficiently thin that the alternating layers constitute a superlattice having a curve of electron velocity versus applied electric field which has a maximum electron velocity at a certain electric field, and wherein the thicknesses of said quantum well layers are selected to provide a superlattice curve of electron velocity versus applied electric field whereby, at applied electric fields higher than that at which the maximum electron velocity occurs in said first material when in bulk form, the electron velocities are higher in said superlattice than they are in said first semiconductor material in bulk form.
Near-infrared branding efficiently correlates light and electron microscopy.
Bishop, Derron; Nikić, Ivana; Brinkoetter, Mary; Knecht, Sharmon; Potz, Stephanie; Kerschensteiner, Martin; Misgeld, Thomas
2011-06-05
The correlation of light and electron microscopy of complex tissues remains a major challenge. Here we report near-infrared branding (NIRB), which facilitates such correlation by using a pulsed, near-infrared laser to create defined fiducial marks in three dimensions in fixed tissue. As these marks are fluorescent and can be photo-oxidized to generate electron contrast, they can guide re-identification of previously imaged structures as small as dendritic spines by electron microscopy.
Poole-Frenkel-effect as dominating current mechanism in thin oxide films—An illusion?!
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schroeder, Herbert
2015-06-07
In many of the publications, over 50 per year for the last five years, the Poole-Frenkel-effect (PFE) is identified or suggested as dominating current mechanism to explain measured current–electric field dependencies in metal-insulator-metal (MIM) thin film stacks. Very often, the insulating thin film is a metal oxide as this class of materials has many important applications, especially in information technology. In the overwhelming majority of the papers, the identification of the PFE as dominating current mechanism is made by the slope of the current–electric field curve in the so-called Poole-Frenkel plot, i.e., logarithm of current density, j, divided by themore » applied electric field, F, versus the square root of that field. This plot is suggested by the simplest current equation for the PFE, which comprises this proportionality (ln(j/F) vs. F{sup 1/2}) leading to a straight line in this plot. Only one other parameter (except natural constants) may influence this slope: the optical dielectric constant of the insulating film. In order to identify the importance of the PFE simulation studies of the current through MIM stacks with thin insulating films were performed and the current–electric field curves without and with implementation of the PFE were compared. For the simulation, an advanced current model has been used combining electronic carrier injection/ejection currents at the interfaces, described by thermionic emission, with the carrier transport in the dielectric, described by drift and diffusion of electrons and holes in a wide band gap semiconductor. Besides the applied electric field (or voltage), many other important parameters have been varied: the density of the traps (with donor- and acceptor-like behavior); the zero-field energy level of the traps within the energy gap, this energy level is changed by the PFE (also called internal Schottky effect); the thickness of the dielectric film; the permittivity of the dielectric film simulating different oxide materials; the barriers for electrons and holes at the interfaces simulating different electrode materials; the temperature. The main results and conclusions are: (1) For a single type of trap present only (donor-like or acceptor-like), none of the simulated current density curves shows the expected behavior of the PFE and in most cases within the tested parameter field the effect of PFE is negligibly small. (2) For both types of traps present (compensation) only in the case of exact compensation, the expected slope in the PF-plot was nearly found for a wider range of the applied electric field, but for a very small range of the tested parameter field because of the very restricting additional conditions: first, the quasi-fermi level of the current controlling particle (electrons or holes) has to be 0.1 to 0.5 eV closer to the respective band limit than the zero-field energy level of the respective traps and, second, the compensating trap energy level has to be shallow. The conclusion from all these results is: the observation of the PFE as dominating current mechanism in MIM stacks with thin dielectric (oxide) films (typically 30 nm) is rather improbable!.« less
Random walk study of electron motion in helium in crossed electromagnetic fields
NASA Technical Reports Server (NTRS)
Englert, G. W.
1972-01-01
Random walk theory, previously adapted to electron motion in the presence of an electric field, is extended to include a transverse magnetic field. In principle, the random walk approach avoids mathematical complexity and concomitant simplifying assumptions and permits determination of energy distributions and transport coefficients within the accuracy of available collisional cross section data. Application is made to a weakly ionized helium gas. Time of relaxation of electron energy distribution, determined by the random walk, is described by simple expressions based on energy exchange between the electron and an effective electric field. The restrictive effect of the magnetic field on electron motion, which increases the required number of collisions per walk to reach a terminal steady state condition, as well as the effect of the magnetic field on electron transport coefficients and mean energy can be quite adequately described by expressions involving only the Hall parameter.
Three dimensional radiation fields in free electron lasers using Lienard-Wiechert fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Elias, L.R.; Gallardo, J.
1981-10-28
In a free electron laser a relativistic electron beam is bunched under the action of the ponderomotive potential and is forced to radiate in close phase with the input wave. Until recently, most theories of the FEL have dealt solely with electron beams of infinite transverse dimension radiating only one-dimensional E.M. waves (plane waves). Although these theories describe accurately the dynamics of the electrons during the FEL interaction process, neither the three dimensional nature of the radiated fields nor its non-monochromatic features can be properly studied by them. As a result of this, very important practical issues such as themore » gain per gaussian-spherical optical mode in a free electron laser have not been well addressed, except through a one dimensional field model in which a filling factor describes crudely the coupling of the FEL induced field to the input field.« less
How enhanced molecular ions in Cold EI improve compound identification by the NIST library.
Alon, Tal; Amirav, Aviv
2015-12-15
Library-based compound identification with electron ionization (EI) mass spectrometry (MS) is a well-established identification method which provides the names and structures of sample compounds up to the isomer level. The library (such as NIST) search algorithm compares different EI mass spectra in the library's database with the measured EI mass spectrum, assigning each of them a similarity score called 'Match' and an overall identification probability. Cold EI, electron ionization of vibrationally cold molecules in supersonic molecular beams, provides mass spectra with all the standard EI fragment ions combined with enhanced Molecular Ions and high-mass fragments. As a result, Cold EI mass spectra differ from those provided by standard EI and tend to yield lower matching scores. However, in most cases, library identification actually improves with Cold EI, as library identification probabilities for the correct library mass spectra increase, despite the lower matching factors. This research examined the way that enhanced molecular ion abundances affect library identification probability and the way that Cold EI mass spectra, which include enhanced molecular ions and high-mass fragment ions, typically improve library identification results. It involved several computer simulations, which incrementally modified the relative abundances of the various ions and analyzed the resulting mass spectra. The simulation results support previous measurements, showing that while enhanced molecular ion and high-mass fragment ions lower the matching factor of the correct library compound, the matching factors of the incorrect library candidates are lowered even more, resulting in a rise in the identification probability for the correct compound. This behavior which was previously observed by analyzing Cold EI mass spectra can be explained by the fact that high-mass ions, and especially the molecular ion, characterize a compound more than low-mass ions and therefore carries more weight in library search identification algorithms. These ions are uniquely abundant in Cold EI, which therefore enables enhanced compound characterization along with improved NIST library based identification. Copyright © 2015 John Wiley & Sons, Ltd.
Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F
2016-07-08
Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases.
Identifying the Tunneling Site in Strong-Field Ionization of H_{2}^{+}.
Liu, Kunlong; Barth, Ingo
2017-12-15
The tunneling site of the electron in a molecule exposed to a strong laser field determines the initial position of the ionizing electron and, as a result, has a large impact on the subsequent ultrafast electron dynamics on the polyatomic Coulomb potential. Here, the tunneling site of the electron of H_{2}^{+} ionized by a strong circularly polarized (CP) laser pulse is studied by numerically solving the time-dependent Schrödinger equation. We show that the electron removed from the down-field site is directly driven away by the CP field and the lateral photoelectron momentum distribution (LPMD) exhibits a Gaussian-like distribution, whereas the corresponding LPMD of the electron removed from the up-field site differs from the Gaussian shape due to the Coulomb focusing and scattering by the down-field core. Our current study presents the direct evidence clarifying a long-standing controversy over the tunneling site in H_{2}^{+} and raises the important role of the tunneling site in strong-field molecular ionization.
Direct acceleration in intense laser fields used for bunch amplification of relativistic electrons
NASA Astrophysics Data System (ADS)
Braenzel, J.; Andreev, A. A.; Ehrentraut, L.; Schnürer, M.
2017-05-01
A method, how electrons can be directly accelerated in intense laser fields, is investigated experimentally and discussed with numerical and analytical simulation. When ultrathin foil targets are exposed with peak laser intensities of 1x1020 W/cm2 , slow electrons ( keV kinetic energy), that are emitted from the ultrathin foil target along laser propagation direction, are post-accelerated in the transmitted laser field. They received significant higher kinetic energies (MeV), when this interaction was limited in duration and an enhanced number of fast electrons were detected. The decoupling of the light field from the electron interaction we realized with a second separator foil, blocking the transmitted laser light at a particular distance and allowing the fast electrons to pass. Variation of the propagation distance in the laser field results in different energy gains for the electrons. This finding is explained with electron acceleration in the electromagnetic field of a light pulse and confirms a concept being discussed for some time. In the experiments the effect manifests in an electron number amplification of about 3 times around a peak at 1 MeV electron energy. Measurements confirmed that the overall number in the whole bunch is enhanced to about 109 electrons covering kinetic energies between 0.5 to 5 MeV. The method holds promise for ultrashort electron bunch generation at MeV energies for direct application, e.g. ultra-fast electron diffraction, or for injection into post accelerator stages for different purposes.
Moving forward: response to "Studying eyewitness investigations in the field".
Ross, Stephen J; Malpass, Roy S
2008-02-01
Field studies of eyewitness identification are richly confounded. Determining which confounds undermine interpretation is important. The blind administration confound in the Illinois study is said to undermine it's value for understanding the relative utility of simultaneous and sequential lineups. Most criticisms of the Illinois study focus on filler identifications, and related inferences about the importance of the blind confound. We find no convincing evidence supporting this line of attack and wonder at filler identifications as the major line of criticism. More debilitating problems impede using the Illinois study to address the simultaneous versus sequential lineup controversy: inability to estimate guilt independent of identification evidence, lack of protocol compliance monitoring, and assessment of lineups quality. Moving forward requires removing these limitations.
Kostamo, K.; Toljamo, A.; Antonius, K.; Kokko, H.; Kärenlampi, S. O.
2013-01-01
Background and Aims Preservation of cultivar purity creates a particular challenge for plants that are self-incompatible, require insects for cross-pollination, and have easily germinating seeds and vigorously spreading rhizomes. As the fields must be planted with mixed populations, and a balance must be maintained between the cultivars to achieve effective pollination, methods for field monitoring of the relative density of different cultivars must be practical. Furthermore, a DNA-based method is needed for cultivar verification in the collections and outside of the growing season. The aim of this study was to develop both types of methods for Rubus arcticus (arctic bramble). Methods Morphological parameters were measured from six cultivars grown on three farms. Observations from the flowers and fruits included: petal and sepal number, flower diameter, arrangement of petals, size of calyx in relation to corolla, fruit weight, yield and soluble sugars. Observations from the leaves included: width and height of middle leaflet, shape of the base of terminal leaflet, shape of terminal leaflet, leaf margin serration and fingertip touch. The applicability of simple sequence repeat (SSR) or microsatellite DNA markers developed for red raspberry was tested on eight arctic bramble cultivars. Key Results and Conclusions Morphological and molecular identification methods were developed for R. arcticus. The best morphological characteristics were the length-to-width ratio of the middle leaflet and leaf margin serration. A particular characteristic, fingertip touch, was shown by electron microscopy to be related to the density and quality of the leaf hairs. Red raspberry SSR marker no. 126 proved to be applicable for differentiation of the eight arctic bramble cultivars tested. These identification methods are critical to secure the maintenance and management of R. arcticus. However, the challenges faced and approaches taken are equally applicable to other species with similar biology. PMID:23456688
NASA Astrophysics Data System (ADS)
Lakhin, V. P.; Ilgisonis, V. I.; Smolyakov, A. I.; Sorokina, E. A.; Marusov, N. A.
2018-01-01
The gradient-drift instabilities of partially magnetized plasmas in plasma devices with crossed electric and magnetic fields are investigated in the framework of the two-fluid model with finite electron temperature in an inhomogeneous magnetic field. The finite electron Larmor radius (FLR) effects are also included via the gyroviscosity tensor taking into account the magnetic field gradient. This model correctly describes the electron dynamics for k⊥ρe>1 in the sense of Padé approximants (here, k⊥ and ρe are the wavenumber perpendicular to the magnetic field and the electron Larmor radius, respectively). The local dispersion relation for electrostatic plasma perturbations with the frequency in the range between the ion and electron cyclotron frequencies and propagating strictly perpendicular to the magnetic field is derived. The dispersion relation includes the effects of the equilibrium E ×B electron current, finite ion velocity, electron inertia, electron FLR, magnetic field gradients, and Debye length effects. The necessary and sufficient condition of stability is derived, and the stability boundary is found. It is shown that, in general, the electron inertia and FLR effects stabilize the short-wavelength perturbations. In some cases, such effects completely suppress the high-frequency short-wavelength modes so that only the long-wavelength low-frequency (with respect to the lower-hybrid frequency) modes remain unstable.
Superspace geometrical realization of the N-extended super Virasoro algebra and its dual
NASA Astrophysics Data System (ADS)
Curto, C.; Gates, S. J., Jr.; Rodgers, V. G. J.
2000-05-01
We derive properties of N-extended /GR super Virasoro algebras. These include adding central extensions, identification of all primary fields and the action of the adjoint representation on its dual. The final result suggest identification with the spectrum of fields in supergravity theories and superstring/M-theory constructed from NSR N-extended supersymmetric /GR Virasoro algebras.
Tahmasebibirgani, Mohammad Javad; Maskani, Reza; Behrooz, Mohammad Ali; Zabihzadeh, Mansour; Shahbazian, Hojatollah; Fatahiasl, Jafar; Chegeni, Nahid
2017-01-01
Introduction In radiotherapy, megaelectron volt (MeV) electrons are employed for treatment of superficial cancers. Magnetic fields can be used for deflection and deformation of the electron flow. A magnetic field is composed of non-uniform permanent magnets. The primary electrons are not mono-energetic and completely parallel. Calculation of electron beam deflection requires using complex mathematical methods. In this study, a device was made to apply a magnetic field to an electron beam and the path of electrons was simulated in the magnetic field using finite element method. Methods A mini-applicator equipped with two neodymium permanent magnets was designed that enables tuning the distance between magnets. This device was placed in a standard applicator of Varian 2100 CD linear accelerator. The mini-applicator was simulated in CST Studio finite element software. Deflection angle and displacement of the electron beam was calculated after passing through the magnetic field. By determining a 2 to 5cm distance between two poles, various intensities of transverse magnetic field was created. The accelerator head was turned so that the deflected electrons became vertical to the water surface. To measure the displacement of the electron beam, EBT2 GafChromic films were employed. After being exposed, the films were scanned using HP G3010 reflection scanner and their optical density was extracted using programming in MATLAB environment. Displacement of the electron beam was compared with results of simulation after applying the magnetic field. Results Simulation results of the magnetic field showed good agreement with measured values. Maximum deflection angle for a 12 MeV beam was 32.9° and minimum deflection for 15 MeV was 12.1°. Measurement with the film showed precision of simulation in predicting the amount of displacement in the electron beam. Conclusion A magnetic mini-applicator was made and simulated using finite element method. Deflection angle and displacement of electron beam were calculated. With the method used in this study, a good prediction of the path of high-energy electrons was made before they entered the body. PMID:28607652
Observation of nanoscale magnetic fields using twisted electron beams
DOE Office of Scientific and Technical Information (OSTI.GOV)
Grillo, Vincenzo; Harvey, Tyler R.; Venturi, Federico
Electron waves give an unprecedented enhancement to the field of microscopy by providing higher resolving power compared to their optical counterpart. Further information about a specimen, such as electric and magnetic features, can be revealed in electron microscopy because electrons possess both a magnetic moment and charge. In-plane magnetic structures in materials can be studied experimentally using the effect of the Lorentz force. On the other hand, full mapping of the magnetic field has hitherto remained challenging. Here we measure a nanoscale out-of-plane magnetic field by interfering a highly twisted electron vortex beam with a reference wave. We implement amore » recently developed holographic technique to manipulate the electron wavefunction, which gives free electrons an additional unbounded quantized magnetic moment along their propagation direction. Our finding demonstrates that full reconstruction of all three components of nanoscale magnetic fields is possible without tilting the specimen.« less
Observation of nanoscale magnetic fields using twisted electron beams
Grillo, Vincenzo; Harvey, Tyler R.; Venturi, Federico; ...
2017-09-25
Electron waves give an unprecedented enhancement to the field of microscopy by providing higher resolving power compared to their optical counterpart. Further information about a specimen, such as electric and magnetic features, can be revealed in electron microscopy because electrons possess both a magnetic moment and charge. In-plane magnetic structures in materials can be studied experimentally using the effect of the Lorentz force. On the other hand, full mapping of the magnetic field has hitherto remained challenging. Here we measure a nanoscale out-of-plane magnetic field by interfering a highly twisted electron vortex beam with a reference wave. We implement amore » recently developed holographic technique to manipulate the electron wavefunction, which gives free electrons an additional unbounded quantized magnetic moment along their propagation direction. Our finding demonstrates that full reconstruction of all three components of nanoscale magnetic fields is possible without tilting the specimen.« less
25th anniversary article: charge transport and recombination in polymer light-emitting diodes.
Kuik, Martijn; Wetzelaer, Gert-Jan A H; Nicolai, Herman T; Craciun, N Irina; De Leeuw, Dago M; Blom, Paul W M
2014-01-01
This article reviews the basic physical processes of charge transport and recombination in organic semiconductors. As a workhorse, LEDs based on a single layer of poly(p-phenylene vinylene) (PPV) derivatives are used. The hole transport in these PPV derivatives is governed by trap-free space-charge-limited conduction, with the mobility depending on the electric field and charge-carrier density. These dependencies are generally described in the framework of hopping transport in a Gaussian density of states distribution. The electron transport on the other hand is orders of magnitude lower than the hole transport. The reason is that electron transport is hindered by the presence of a universal electron trap, located at 3.6 eV below vacuum with a typical density of ca. 3 × 10¹⁷ cm⁻³. The trapped electrons recombine with free holes via a non-radiative trap-assisted recombination process, which is a competing loss process with respect to the emissive bimolecular Langevin recombination. The trap-assisted recombination in disordered organic semiconductors is governed by the diffusion of the free carrier (hole) towards the trapped carrier (electron), similar to the Langevin recombination of free carriers where both carriers are mobile. As a result, with the charge-carrier mobilities and amount of trapping centers known from charge-transport measurements, the radiative recombination as well as loss processes in disordered organic semiconductors can be fully predicted. Evidently, future work should focus on the identification and removing of electron traps. This will not only eliminate the non-radiative trap-assisted recombination, but, in addition, will shift the recombination zone towards the center of the device, leading to an efficiency improvement of more than a factor of two in single-layer polymer LEDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Anderson, Lissa C; DeHart, Caroline J; Kaiser, Nathan K; Fellers, Ryan T; Smith, Donald F; Greer, Joseph B; LeDuc, Richard D; Blakney, Greg T; Thomas, Paul M; Kelleher, Neil L; Hendrickson, Christopher L
2017-02-03
Successful high-throughput characterization of intact proteins from complex biological samples by mass spectrometry requires instrumentation capable of high mass resolving power, mass accuracy, sensitivity, and spectral acquisition rate. These limitations often necessitate the performance of hundreds of LC-MS/MS experiments to obtain reasonable coverage of the targeted proteome, which is still typically limited to molecular weights below 30 kDa. The National High Magnetic Field Laboratory (NHMFL) recently installed a 21 T FT-ICR mass spectrometer, which is part of the NHMFL FT-ICR User Facility and available to all qualified users. Here we demonstrate top-down LC-21 T FT-ICR MS/MS of intact proteins derived from human colorectal cancer cell lysate. We identified a combined total of 684 unique protein entries observed as 3238 unique proteoforms at a 1% false discovery rate, based on rapid, data-dependent acquisition of collision-induced and electron-transfer dissociation tandem mass spectra from just 40 LC-MS/MS experiments. Our identifications included 372 proteoforms with molecular weights over 30 kDa detected at isotopic resolution, which substantially extends the accessible mass range for high-throughput top-down LC-MS/MS.
DIII-D Neutron Measurement: Status and Plan for Simplification and Upgrade
NASA Astrophysics Data System (ADS)
Zhu, Y. B.; Heidbrink, W. W.; Taylor, P. L.; Finkenthal, D.
2017-10-01
Neutron diagnostics play key essential roles on DIII-D. Historically an 18-channel 2.45MeV D-D neutron measurement system based on 3He and BF3 proportional counters was inherited from Doublet-III including associated electronics and CAMAC data acquisition. Three fission chambers and two neutron scintillators were added in the 1980s and middle 1990s respectively. For Tritium burn-up studies, two 14MeV D-T neutron measurement systems were installed in 2009 and 2010. Operation and maintenance experience have led to a plan to simplify and upgrade these aging systems to provide a more economical and reliable solution for future DIII-D experiments. On simplification, most conventional expensive NIM and CAMAC modules will be removed. Advanced technologies like ultra-fast data acquisition and software-based pulse identification have been successfully tested. Significant data reduction and efficiency improvement will be achieved by real-time digital pulse identification with a field-programmable gate array. The partly renewed system will consist of 4 neutron counters for absolute calibration and 4 relatively calibrated neutron scintillators covering a wide measurement range. Work supported by US DOE under DE-FC02-04ER54698.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Huanyu; Lu, Quanming; Huang, Can
2016-04-20
The interactions between magnetic islands are considered to play an important role in electron acceleration during magnetic reconnection. In this paper, two-dimensional particle-in-cell simulations are performed to study electron acceleration during multiple X line reconnection with a guide field. Because the electrons remain almost magnetized, we can analyze the contributions of the parallel electric field, Fermi, and betatron mechanisms to electron acceleration during the evolution of magnetic reconnection through comparison with a guide-center theory. The results show that with the magnetic reconnection proceeding, two magnetic islands are formed in the simulation domain. Next, the electrons are accelerated by both themore » parallel electric field in the vicinity of the X lines and the Fermi mechanism due to the contraction of the two magnetic islands. Then, the two magnetic islands begin to merge into one, and, in such a process, the electrons can be accelerated by both the parallel electric field and betatron mechanisms. During the betatron acceleration, the electrons are locally accelerated in the regions where the magnetic field is piled up by the high-speed flow from the X line. At last, when the coalescence of the two islands into one big island finishes, the electrons can be further accelerated by the Fermi mechanism because of the contraction of the big island. With the increase of the guide field, the contributions of the Fermi and betatron mechanisms to electron acceleration become less and less important. When the guide field is sufficiently large, the contributions of the Fermi and betatron mechanisms are almost negligible.« less
[Study of cuttings identification using laser-induced breakdown spectroscopy].
Tian, Ye; Wang, Zhen-nan; Hou, Hua-ming; Zhai, Xiao-wei; Ci, Xing-hua; Zheng, Rong-er
2012-08-01
Cutting identification is one of the most important links in the course of cutting logging which is very significant in the process of oil drilling. In the present paper, LIBS was used for identification of four kinds of cutting samples coming from logging field, and then multivariate analysis was used in data processing. The whole spectra model and the feature model were built for cuttings identification using PLS-DA method. The accuracy of the whole spectra model was 88.3%, a little more than the feature model with an accuracy of 86.7%. While in the aspect of data size, the variables were decreased from 24,041 to 27 by feature extraction, which increased the efficiency of data processing observably. The obtained results demonstrate that LIBS combined with chemometrics method could be developed as a rapid and valid approach to cutting identification and has great potential to be used in logging field.
Li, Sha; Jones, R. R.
2016-01-01
Electrons ejected from atoms and subsequently driven to high energies in strong laser fields enable techniques from attosecond pulse generation to imaging with rescattered electrons. Analogous processes govern strong-field electron emission from nanostructures, where long wavelength radiation and large local field enhancements hold the promise for producing electrons with substantially higher energies, allowing for higher resolution time-resolved imaging. Here we report on the use of single-cycle terahertz pulses to drive electron emission from unbiased nano-tips. Energies exceeding 5 keV are observed, substantially greater than previously attained at higher drive frequencies. Despite large differences in the magnitude of the respective local fields, we find that the maximum electron energies are only weakly dependent on the tip radius, for 10 nm
A reexamination of pitch angle diffusion of electrons at the boundary of the lunar wake
NASA Astrophysics Data System (ADS)
Nakagawa, T.; Iizima, M.
2006-05-01
Velocity distribution of the solar wind electrons injected into the lunar wake boundary is re-examined by using a simple model structure of inward electric field. The electrons that were flowing along the magnetic field lines undergo pitch angle scattering due to the electric field component perpendicular to the magnetic field. The electrons obtain perpendicular speeds twice as much as the drift speed. On the basis of the GEOTAIL observations of the whistler mode waves and strahl electrons, the intensity of the electric field and the thickness of the wake structure are estimated to be 28-40 mVm-1 and less than 20 km, respectively.
Using Strategic Communications to Address Critical Threats to Border Security
2009-04-01
Frequency Identification in November of 2008. This technology forces people to hold up their identification card to an electronic scanner before they pull...podcasts via Texas A&Ms iTunes University to reach out to a greater number of people. Because radio remains a part of the American way of life, it
Authentication of Radio Frequency Identification Devices Using Electronic Characteristics
ERIC Educational Resources Information Center
Chinnappa Gounder Periaswamy, Senthilkumar
2010-01-01
Radio frequency identification (RFID) tags are low-cost devices that are used to uniquely identify the objects to which they are attached. Due to the low cost and size that is driving the technology, a tag has limited computational capabilities and resources. This limitation makes the implementation of conventional security protocols to prevent…
41 CFR 109-38.5203 - Watercraft identification and numbers.
Code of Federal Regulations, 2011 CFR
2011-01-01
... identification and numbers. 109-38.5203 Section 109-38.5203 Public Contracts and Property Management Federal... Watercraft identification and numbers. Watercraft in the custody of DOE or designated contractors shall display identifying numbers, whether issued by the U.S. Coast Guard, State, or local field organization...
Guiding-center equations for electrons in ultraintense laser fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Moore, J.E.; Fisch, N.J.
1994-01-01
The guiding-center equations are derived for electrons in arbitrarily intense laser fields also subject to external fields and ponderomotive forces. Exhibiting the relativistic mass increase of the oscillating electrons, a simple frame-invariant equation is shown to govern the behavior of the electrons for sufficiently weak background fields and ponderomotive forces. The parameter regime for which such a formulation is valid is made precise, and some predictions of the equation are checked by numerical simulation.
78 FR 12322 - Agency Information Collection Activities: OMB Review; Comment Request
Federal Register 2010, 2011, 2012, 2013, 2014
2013-02-22
... Interchange (EDI) Registration and Electronic Data Interchange (EDI) Enrollment Form; Use: The purpose of this... identification of Medicare providers/suppliers and authorization of requested Electronic Data Interface (EDI) functions. The EDI Enrollment and the Medicare Registration Forms are completed by Medicare providers...
NASA Technical Reports Server (NTRS)
Baer-Riedhart, Jennifer L.; Landy, Robert J.
1987-01-01
The highly integrated digital electronic control (HIDEC) program at NASA Ames Research Center, Dryden Flight Research Facility is a multiphase flight research program to quantify the benefits of promising integrated control systems. McDonnell Aircraft Company is the prime contractor, with United Technologies Pratt and Whitney Aircraft, and Lear Siegler Incorporated as major subcontractors. The NASA F-15A testbed aircraft was modified by the HIDEC program by installing a digital electronic flight control system (DEFCS) and replacing the standard F100 (Arab 3) engines with F100 engine model derivative (EMD) engines equipped with digital electronic engine controls (DEEC), and integrating the DEEC's and DEFCS. The modified aircraft provides the capability for testing many integrated control modes involving the flight controls, engine controls, and inlet controls. This paper focuses on the first two phases of the HIDEC program, which are the digital flight control system/aircraft model identification (DEFCS/AMI) phase and the adaptive engine control system (ADECS) phase.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kong, Xiangliang; Chen, Yao; Feng, Shiwei
2016-04-10
Using a test-particle simulation, we investigate the effect of large-scale coronal magnetic fields on electron acceleration at an outward-propagating coronal shock with a circular front. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featuring a partially open magnetic field and a current sheet at the equator atop the closed region. We show that the large-scale shock-field configuration, especially the relative curvature of the shock and the magnetic field line across which the shock is sweeping, plays an important role in the efficiency of electron acceleration. At low shock altitudes, when the shock curvature ismore » larger than that of the magnetic field lines, the electrons are mainly accelerated at the shock flanks; at higher altitudes, when the shock curvature is smaller, the electrons are mainly accelerated at the shock nose around the top of closed field lines. The above process reveals the shift of the efficient electron acceleration region along the shock front during its propagation. We also find that, in general, the electron acceleration at the shock flank is not as efficient as that at the top of the closed field because a collapsing magnetic trap can be formed at the top. In addition, we find that the energy spectra of electrons are power-law-like, first hardening then softening with the spectral index varying in a range of −3 to −6. Physical interpretations of the results and implications for the study of solar radio bursts are discussed.« less
Kong, Xiangliang; Chen, Yao; Guo, Fan; ...
2016-04-05
With a test-particle simulation, we investigate the effect of large-scale coronal magnetic fields on electron acceleration at an outward-propagating coronal shock with a circular front. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. We show that the large-scale shock-field configuration, especially the relative curvature of the shock and the magnetic field line across which the shock is sweeping, plays an important role in the efficiency of electron acceleration. At low shock altitudes, when the shock curvature ismore » larger than that of magnetic field lines, the electrons are mainly accelerated at the shock flanks; at higher altitudes, when the shock curvature is smaller, the electrons are mainly accelerated at the shock nose around the top of closed field lines. The above process reveals the shift of efficient electron acceleration region along the shock front during its propagation. We also found that in general the electron acceleration at the shock flank is not so efficient as that at the top of closed field since at the top a collapsing magnetic trap can be formed. In addition, we find that the energy spectra of electrons is power-law like, first hardening then softening with the spectral index varying in a range of -3 to -6. In conclusion, physical interpretations of the results and implications on the study of solar radio bursts are discussed.« less
NASA Astrophysics Data System (ADS)
Wu, D.; Luan, S. X.; Wang, J. W.; Yu, W.; Gong, J. X.; Cao, L. H.; Zheng, C. Y.; He, X. T.
2017-06-01
The two-stage electron acceleration/heating model (Wu et al 2017 Nucl. Fusion 57 016007 and Wu et al 2016 Phys. Plasmas 23 123116) is extended to the study of laser magnetized-plasmas interactions at relativistic intensities and in the presence of large-scale preformed plasmas. It is shown that the electron-heating efficiency is a controllable value by the external magnetic fields. Detailed studies indicate that for a right-hand circularly polarized laser, the electron heating efficiency depends on both strength and directions of external magnetic fields. The electron-heating is dramatically enhanced when the external magnetic field is of B\\equiv {ω }c/{ω }0> 1. When magnetic field is of negative direction, i.e. B< 0, it trends to suppress the electron heating. The underlining physics—the dependences of electron-heating on both the strength and directions of the external magnetic fields—is uncovered. With -∞ < B< 1, the electron-heating is explained by the synergetic effects by longitudinal charge separation electric field and the reflected ‘envelop-modulated’ CP laser. It is indicated that the ‘modulation depth’ of reflected CP laser is significantly determined by the external magnetic fields, which will in turn influence the efficiency of the electron-heating. While with B> 1, a laser front sharpening mechanism is identified at relativistic laser magnetized-plasmas interactions, which is responsible for the dramatical enhancement of electron-heating.
Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.
Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S
2016-02-01
The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H(-) ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H(-) ion generation in volume-produced negative hydrogen ion sources.
Electron energy recovery system for negative ion sources
Dagenhart, William K.; Stirling, William L.
1982-01-01
An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90.degree. to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy.
Beam induced electron cloud resonances in dipole magnetic fields
Calvey, J. R.; Hartung, W.; Makita, J.; ...
2016-07-01
The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring. Thesemore » measurements are supported by both analytical models and computer simulations.« less
Sekine, Ryo; Moore, Katie L; Matzke, Marianne; Vallotton, Pascal; Jiang, Haibo; Hughes, Gareth M; Kirby, Jason K; Donner, Erica; Grovenor, Chris R M; Svendsen, Claus; Lombi, Enzo
2017-11-28
Increasing consumer use of engineered nanomaterials has led to significantly increased efforts to understand their potential impact on the environment and living organisms. Currently, no individual technique can provide all the necessary information such as their size, distribution, and chemistry in complex biological systems. Consequently, there is a need to develop complementary instrumental imaging approaches that provide enhanced understanding of these "bio-nano" interactions to overcome the limitations of individual techniques. Here we used a multimodal imaging approach incorporating dark-field light microscopy, high-resolution electron microscopy, and nanoscale secondary ion mass spectrometry (NanoSIMS). The aim was to gain insight into the bio-nano interactions of surface-functionalized silver nanoparticles (Ag-NPs) with the green algae Raphidocelis subcapitata, by combining the fidelity, spatial resolution, and elemental identification offered by the three techniques, respectively. Each technique revealed that Ag-NPs interact with the green algae with a dependence on the size (10 nm vs 60 nm) and surface functionality (tannic acid vs branched polyethylenimine, bPEI) of the NPs. Dark-field light microscopy revealed the presence of strong light scatterers on the algal cell surface, and SEM imaging confirmed their nanoparticulate nature and localization at nanoscale resolution. NanoSIMS imaging confirmed their chemical identity as Ag, with the majority of signal concentrated at the cell surface. Furthermore, SEM and NanoSIMS provided evidence of 10 nm bPEI Ag-NP internalization at higher concentrations (40 μg/L), correlating with the highest toxicity observed from these NPs. This multimodal approach thus demonstrated an effective approach to complement dose-response studies in nano-(eco)-toxicological investigations.
Cox, Zachary L; Lewis, Connie M; Lai, Pikki; Lenihan, Daniel J
2017-01-01
We aim to validate the diagnostic performance of the first fully automatic, electronic heart failure (HF) identification algorithm and evaluate the implementation of an HF Dashboard system with 2 components: real-time identification of decompensated HF admissions and accurate characterization of disease characteristics and medical therapy. We constructed an HF identification algorithm requiring 3 of 4 identifiers: B-type natriuretic peptide >400 pg/mL; admitting HF diagnosis; history of HF International Classification of Disease, Ninth Revision, diagnosis codes; and intravenous diuretic administration. We validated the diagnostic accuracy of the components individually (n = 366) and combined in the HF algorithm (n = 150) compared with a blinded provider panel in 2 separate cohorts. We built an HF Dashboard within the electronic medical record characterizing the disease and medical therapies of HF admissions identified by the HF algorithm. We evaluated the HF Dashboard's performance over 26 months of clinical use. Individually, the algorithm components displayed variable sensitivity and specificity, respectively: B-type natriuretic peptide >400 pg/mL (89% and 87%); diuretic (80% and 92%); and International Classification of Disease, Ninth Revision, code (56% and 95%). The HF algorithm achieved a high specificity (95%), positive predictive value (82%), and negative predictive value (85%) but achieved limited sensitivity (56%) secondary to missing provider-generated identification data. The HF Dashboard identified and characterized 3147 HF admissions over 26 months. Automated identification and characterization systems can be developed and used with a substantial degree of specificity for the diagnosis of decompensated HF, although sensitivity is limited by clinical data input. Copyright © 2016 Elsevier Inc. All rights reserved.
NASA Astrophysics Data System (ADS)
Dass, Devi
2018-03-01
Graphene nanoribbon (GNR), a new 2D carbon nanomaterial, has some unique features and special properties that offer a great potential for interconnect, nanoelectronic devices, optoelectronics, and nanophotonics. This paper reports the structural analysis, electronic properties, and band gaps of a GNR considering different chirality combinations obtained using the pz orbital tight binding model. In structural analysis, the analytical expressions for GNRs have been developed and verified using the simulation for the first time. It has been found that the total number of unit cells and carbon atoms within an overall unit cell and molecular structure of a GNR have been changed with the change in their chirality values which are similar to the values calculated using the developed analytical expressions thus validating both the simulation as well as analytical results. Further, the electronic band structures at different chirality values have been shown for the identification of metallic and semiconductor properties of a GNR. It has been concluded that all zigzag edge GNRs are metallic with very small band gaps range whereas all armchair GNRs show both the metallic and semiconductor nature with very small and high band gaps range. Again, the total number of subbands in each electronic band structure is equal to the total number of carbon atoms present in overall unit cell of the corresponding GNR. The semiconductors GNRs can be used as a channel material in field effect transistor suitable for advanced CMOS technology whereas the metallic GNRs could be used for interconnect.
Electronic workflow for imaging in clinical research.
Hedges, Rebecca A; Goodman, Danielle; Sachs, Peter B
2014-08-01
In the transition from paper to electronic workflow, the University of Colorado Health System's implementation of a new electronic health record system (EHR) forced all clinical groups to reevaluate their practices including the infrastructure surrounding clinical trials. Radiological imaging is an important piece of many clinical trials and requires a high level of consistency and standardization. With EHR implementation, paper orders were manually transcribed into the EHR, digitizing an inefficient work flow. A team of schedulers, radiologists, technologists, research personnel, and EHR analysts worked together to optimize the EHR to accommodate the needs of research imaging protocols. The transition to electronic workflow posed several problems: (1) there needed to be effective communication throughout the imaging process from scheduling to radiologist interpretation. (2) The exam ordering process needed to be automated to allow scheduling of specific research studies on specific equipment. (3) The billing process needed to be controlled to accommodate radiologists already supported by grants. (4) There needed to be functionality allowing exams to finalize automatically skipping the PACS and interpretation process. (5) There needed to be a way to alert radiologists that a specialized research interpretation was needed on a given exam. These issues were resolved through the optimization of the "visit type," allowing a high-level control of an exam at the time of scheduling. Additionally, we added columns and fields to work queues displaying grant identification numbers. The build solutions we implemented reduced the mistakes made and increased imaging quality and compliance.
NASA Astrophysics Data System (ADS)
Ozaki, T.; Hata, M.; Matsuo, K.; Kojima, S.; Arikawa, Y.; Fujioka, S.; Sakagami, H.; Sunahara, A.; Nagatomo, H.; Johzaki, T.; Yogo, A.; Morace, A.; Zhang, Z.; Shiraga, H.; Sakata, S.; Nagai, T.; Abe, Y.; Lee, S.; Nakai, M.; Nishimura, H.; Azechi, H.; FIREX Group; GXII-LFEX Group
2016-05-01
Hot electrons which are generated from targets irradiated by a high-intense laser are measured by two electron spectrometers (ESMs). However, total electron energy observed by the ESM is only less than 1%. Hot electrons are confined by self-fields due to the huge current. When an external magnetic field of several hundred Tesla is applied during the laser irradiation on targets, the ESM signals always increase. In the simulation, the same result can be obtained. The reason is that the Alfvén limit can be mitigated due to the external longitudinal magnetic field.
Penetration length-dependent hot electrons in the field emission from ZnO nanowires
NASA Astrophysics Data System (ADS)
Chen, Yicong; Song, Xiaomeng; Li, Zhibing; She, Juncong; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun
2018-01-01
In the framework of field emission, whether or not hot electrons can form in the semiconductor emitters under a surface penetration field is of great concern, which will provide not only a comprehensive physical picture of field emission from semiconductor but also guidance on how to improve device performance. However, apart from some theoretical work, its experimental evidence has not been reported yet. In this article, the field penetration length-dependent hot electrons were observed in the field emission of ZnO nanowires through the in-situ study of its electrical and field emission characteristic before and after NH3 plasma treatment in an ultrahigh vacuum system. After the treatment, most of the nanowires have an increased carrier density but reduced field emission current. The raised carrier density was caused by the increased content of oxygen vacancies, while the degraded field emission current was attributed to the lower kinetic energy of hot electrons caused by the shorter penetration length. All of these results suggest that the field emission properties of ZnO nanowires can be optimized by modifying their carrier density to balance both the kinetic energy of field induced hot electrons and the limitation of saturated current under a given field.
Organizational Identification and Social Motivation: A Field Descriptive Study in Two Organizations.
ERIC Educational Resources Information Center
Barge, J. Kevin
A study examined the relationships between leadership conversation and its impact upon organizational members' levels of organizational identification and behavior. It was hypothesized (1) that effective leader conversation would be associated with higher levels of role, means, goal and overall organizational identification, and (2) that…
Bar code-based pre-transfusion check in pre-operative autologous blood donation.
Ohsaka, Akimichi; Furuta, Yoshiaki; Ohsawa, Toshiya; Kobayashi, Mitsue; Abe, Katsumi; Inada, Eiichi
2010-10-01
The objective of this study was to demonstrate the feasibility of a bar code-based identification system for the pre-transfusion check at the bedside in the setting of pre-operative autologous blood donation (PABD). Between July 2003 and December 2008 we determined the compliance rate and causes of failure of electronic bedside checking for PABD transfusion. A total of 5627 (9% of all transfusions) PABD units were administered without a single mistransfusion. The overall rate of compliance with electronic checking was 99%. The bar code-based identification system was applicable to the pre-transfusion check for PABD transfusion. Copyright © 2010 Elsevier Ltd. All rights reserved.
Methodology for creating dedicated machine and algorithm on sunflower counting
NASA Astrophysics Data System (ADS)
Muracciole, Vincent; Plainchault, Patrick; Mannino, Maria-Rosaria; Bertrand, Dominique; Vigouroux, Bertrand
2007-09-01
In order to sell grain lots in European countries, seed industries need a government certification. This certification requests purity testing, seed counting in order to quantify specified seed species and other impurities in lots, and germination testing. These analyses are carried out within the framework of international trade according to the methods of the International Seed Testing Association. Presently these different analyses are still achieved manually by skilled operators. Previous works have already shown that seeds can be characterized by around 110 visual features (morphology, colour, texture), and thus have presented several identification algorithms. Until now, most of the works in this domain are computer based. The approach presented in this article is based on the design of dedicated electronic vision machine aimed to identify and sort seeds. This machine is composed of a FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processor) and a PC bearing the GUI (Human Machine Interface) of the system. Its operation relies on the stroboscopic image acquisition of a seed falling in front of a camera. A first machine was designed according to this approach, in order to simulate all the vision chain (image acquisition, feature extraction, identification) under the Matlab environment. In order to perform this task into dedicated hardware, all these algorithms were developed without the use of the Matlab toolbox. The objective of this article is to present a design methodology for a special purpose identification algorithm based on distance between groups into dedicated hardware machine for seed counting.
Schreiver, Ines; Hutzler, Christoph; Andree, Sarah; Laux, Peter; Luch, Andreas
2016-07-01
The implementation of regulation for tattoo ink ingredients across Europe has generated the need for analytical methods suitable to identify prohibited compounds. Common challenges of this subject are the poor solubility and the lack of volatility for most pigments and polymers applied in tattoo inks. Here, we present pyrolysis coupled to online gas chromatography and electron impact ionization mass spectrometry (py-GC/MS) as quick and reliable tool for pigment identification using both purified pigments and tattoo ink formulations. Some 36 organic pigments frequently used in tattoo inks were subjected to py-GC/MS with the aim to establish a pyrogram library. To cross-validate pigment identification, 28 commercially available tattoo inks as well as 18 self-made pigment mixtures were analyzed. Pyrograms of inks and mixtures were evaluated by two different means to work out the most reliable and fastest strategy for an otherwise rather time-consuming data review. Using this approach, the declaration of tattoo pigments currently used on the market could be verified. The pyrolysis library presented here is also assumed suitable to predict decomposition patterns of pigments when affected by other degradation scenarios, such as sunlight exposure or laser irradiation. Thus, the consumers' risk associated with the exposure to toxicologically relevant substances that originate from pigment decomposition in the dermal layers of the skin can be assessed. Differentiation between more or less harmful pigments for this field of application now will become feasible.
Investigation on the optimal magnetic field of a cusp electron gun for a W-band gyro-TWA
NASA Astrophysics Data System (ADS)
Zhang, Liang; He, Wenlong; Donaldson, Craig R.; Cross, Adrian W.
2018-05-01
High efficiency and broadband operation of a gyrotron traveling wave amplifier (gyro-TWA) require a high-quality electron beam with low-velocity spreads. The beam velocity spreads are mainly due to the differences of the electric and magnetic fields that the electrons withstand the electron gun. This paper investigates the possibility to decouple the design of electron gun geometry and the magnet system while still achieving optimal results, through a case study of designing a cusp electron gun for a W-band gyro-TWA. A global multiple-objective optimization routing was used to optimize the electron gun geometry for different predefined magnetic field profiles individually. Their results were compared and the properties of the required magnetic field profile are summarized.
Direct Measurement of Polarization-Induced Fields in GaN/AlN by Nano-Beam Electron Diffraction
NASA Astrophysics Data System (ADS)
Carvalho, Daniel; Müller-Caspary, Knut; Schowalter, Marco; Grieb, Tim; Mehrtens, Thorsten; Rosenauer, Andreas; Ben, Teresa; García, Rafael; Redondo-Cubero, Andrés; Lorenz, Katharina; Daudin, Bruno; Morales, Francisco M.
2016-06-01
The built-in piezoelectric fields in group III-nitrides can act as road blocks on the way to maximizing the efficiency of opto-electronic devices. In order to overcome this limitation, a proper characterization of these fields is necessary. In this work nano-beam electron diffraction in scanning transmission electron microscopy mode has been used to simultaneously measure the strain state and the induced piezoelectric fields in a GaN/AlN multiple quantum well system.
EPR/PTFE dosimetry for test reactor environments
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vehar, D.W.; Griffin, P.J.; Quirk, T.J.
2011-07-01
The use of Electron Paramagnetic Resonance (EPR) spectroscopy with materials such as alanine is well established as a technique for measurement of ionizing radiation absorbed dose in photon and electron fields such as Co-60, high-energy bremsstrahlung and electron-beam fields [1]. In fact, EPR/Alanine dosimetry has become a routine transfer standard for national standards bodies such as NIST and NPL. In 1992 the Radiation Metrology Laboratory (RML) at Sandia National Laboratories implemented EPR/Alanine capabilities for use in routine and calibration activities at its Co-60 and pulsed-power facilities. At that time it also investigated the usefulness of the system for measurement ofmore » absorbed dose in the mixed neutron/photon environments of reactors such as the Sandia Pulsed Reactor and the Annular Core Research Reactor used for hardness testing of electronics. The RML concluded that the neutron response of alanine was a sufficiently high fraction of the overall dosimeter response that the resulting uncertainties in the photon dose would be unacceptably large for silicon-device testing. However, it also suggested that non-hydrogenous materials such as polytetrafluoroethylene (PTFE) would exhibit smaller neutron response and might be useful in mixed environments. Preliminary research with PTFE in photon environments indicated considerable promise, but further development was not pursued at that time. Because of renewed interest in absorbed dose measurements that could better define the individual contributions of photon and neutron components to the overall dose delivered to a test object, the RML has re-initiated the development of an EPR/PTFE dosimetry system. This effort consists of three stages: 1) Identification of PTFE materials that may be suitable for dosimetry applications. It was speculated that the inconsistency of EPR signatures in the earlier samples may have been due to variability in PTFE manufacturing processes. 2) Characterization of dosimetry in photon-only environments. This is necessary to establish requirements for sample preparation, operating parameters and limitations for use in well-defined and predictable environments prior to deployment in the less well-defined mixed environments of test reactors. 3) Characterization of the EPR responses obtained with PTFE in mixed neutron/photon fields. This includes evaluation of the neutron and photon contributions to response, determination of applicable of neutron fluence and photon dose ranges. This paper presents a summary of the research, a description of the EPR/PTFE dosimetry system, and recommendations for preparation and fielding of the dosimetry in photon and mixed neutron/photon environments. (authors)« less
Theory for the anomalous electron transport in Hall-effect thrusters
NASA Astrophysics Data System (ADS)
Lafleur, Trevor; Baalrud, Scott; Chabert, Pascal
2016-09-01
Using insights from particle-in-cell (PIC) simulations, we develop a kinetic theory to explain the anomalous cross-field electron transport in Hall-effect thrusters (HETs). The large axial electric field in the acceleration region of HETs, together with the radially applied magnetic field, causes electrons to drift in the azimuthal direction with a very high velocity. This drives an electron cyclotron instability that produces large amplitude oscillations in the plasma density and azimuthal electric field, and which is convected downstream due to the large axial ion drift velocity. The frequency and wavelength of the instability are of the order of 5 MHz and 1 mm respectively, while the electric field amplitude can be of a similar magnitude to axial electric field itself. The instability leads to enhanced electron scattering many orders of magnitude higher than that from standard electron-neutral or electron-ion Coulomb collisions, and gives electron mobilities in good agreement with experiment. Since the instability is a strong function of almost all plasma properties, the mobility cannot in general be fitted with simple 1/B or 1/B2 scaling laws, and changes to the secondary electron emission coefficient of the HET channel walls are expected to play a role in the evolution of the instability. This work received financial support from a CNES postdoctoral research award.
NASA Astrophysics Data System (ADS)
Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Lejosne, S.
2014-12-01
A huge number of different non-linear structures (double layers, electron holes, non-linear whistlers, etc) have been observed by the electric field experiment on the Van Allen Probes in conjunction with relativistic electron acceleration in the Earth's outer radiation belt. These structures, found as short duration (~0.1 msec) quasi-periodic bursts of electric field in the high time resolution electric field waveform, have been called Time Domain Structures (TDS). They can quite effectively interact with radiation belt electrons. Due to the trapping of electrons into these non-linear structures, they are accelerated up to ~10 keV and their pitch angles are changed, especially for low energies (˜1 keV). Large amplitude electric field perturbations cause non-linear resonant trapping of electrons into the effective potential of the TDS and these electrons are then accelerated in the non-homogeneous magnetic field. These locally accelerated electrons create the "seed population" of several keV electrons that can be accelerated by coherent, large amplitude, upper band whistler waves to MeV energies in this two step acceleration process. All the elements of this chain acceleration mechanism have been observed by the Van Allen Probes.
Süßmann, F.; Seiffert, L.; Zherebtsov, S.; Mondes, V.; Stierle, J.; Arbeiter, M.; Plenge, J.; Rupp, P.; Peltz, C.; Kessel, A.; Trushin, S. A.; Ahn, B.; Kim, D.; Graf, C.; Rühl, E.; Kling, M. F.; Fennel, T.
2015-01-01
Near-fields of non-resonantly laser-excited nanostructures enable strong localization of ultrashort light fields and have opened novel routes to fundamentally modify and control electronic strong-field processes. Harnessing spatiotemporally tunable near-fields for the steering of sub-cycle electron dynamics may enable ultrafast optoelectronic devices and unprecedented control in the generation of attosecond electron and photon pulses. Here we utilize unsupported sub-wavelength dielectric nanospheres to generate near-fields with adjustable structure and study the resulting strong-field dynamics via photoelectron imaging. We demonstrate field propagation-induced tunability of the emission direction of fast recollision electrons up to a regime, where nonlinear charge interaction effects become dominant in the acceleration process. Our analysis supports that the timing of the recollision process remains controllable with attosecond resolution by the carrier-envelope phase, indicating the possibility to expand near-field-mediated control far into the realm of high-field phenomena. PMID:26264422
Süßmann, F; Seiffert, L; Zherebtsov, S; Mondes, V; Stierle, J; Arbeiter, M; Plenge, J; Rupp, P; Peltz, C; Kessel, A; Trushin, S A; Ahn, B; Kim, D; Graf, C; Rühl, E; Kling, M F; Fennel, T
2015-08-12
Near-fields of non-resonantly laser-excited nanostructures enable strong localization of ultrashort light fields and have opened novel routes to fundamentally modify and control electronic strong-field processes. Harnessing spatiotemporally tunable near-fields for the steering of sub-cycle electron dynamics may enable ultrafast optoelectronic devices and unprecedented control in the generation of attosecond electron and photon pulses. Here we utilize unsupported sub-wavelength dielectric nanospheres to generate near-fields with adjustable structure and study the resulting strong-field dynamics via photoelectron imaging. We demonstrate field propagation-induced tunability of the emission direction of fast recollision electrons up to a regime, where nonlinear charge interaction effects become dominant in the acceleration process. Our analysis supports that the timing of the recollision process remains controllable with attosecond resolution by the carrier-envelope phase, indicating the possibility to expand near-field-mediated control far into the realm of high-field phenomena.
NASA Astrophysics Data System (ADS)
Raitses, Yevgeny; Donnelly, Vincent M.; Kaganovich, Igor D.; Godyak, Valery
2013-10-01
The application of the magnetic field in a low pressure plasma can cause a spatial separation of cold and hot electron groups. This so-called magnetic filter effect is not well understood and is the subject of our studies. In this work, we investigate electron energy distribution function in a DC-RF plasma discharge with crossed electric and magnetic field operating at sub-mtorr pressure range of xenon gas. Experimental studies showed that the increase of the magnetic field leads to a more uniform profile of the electron temperature across the magnetic field. This surprising result indicates the importance of anomalous electron transport that causes mixing of hot and cold electrons. High-speed imaging and probe measurements revealed a coherent structure rotating in E cross B direction with frequency of a few kHz. Similar to spoke oscillations reported for Hall thrusters, this rotating structure conducts the largest fraction of the cross-field current. This work was supported by DOE contract DE-AC02-09CH11466.
NASA Astrophysics Data System (ADS)
Raitses, Yevgeny; Donnelly, Vincent; Kaganovich, Igor; Godyak, Valery
2013-09-01
The application of the magnetic field in a low pressure plasma can cause a spatial separation of cold and hot electron groups. This so-called magnetic filter effect is not well understood and is the subject of our studies. In this work, we investigate electron energy distribution function in a DC-RF plasma discharge with crossed electric and magnetic field operating at sub-mtorr pressure range of xenon gas. Experimental studies showed that the increase of the magnetic field leads to a more uniform profile of the electron temperature across the magnetic field. This surprising result indicates the importance of anomalous electron transport that causes mixing of hot and cold electrons. High-speed imaging and probe measurements revealed a coherent structure rotating in E cross B direction with frequency of a few kHz. Similar to spoke oscillations reported for Hall thrusters, this rotating structure conducts the largest fraction of the cross-field current. This work was supported by the US DOE under Contract DE-AC02-09CH11466.
47 CFR 36.125 - Local switching equipment-Category 3.
Code of Federal Regulations, 2010 CFR
2010-10-01
... electronic analog or digital remote line locations. Equipment used for the identification, recording and... which has a common intermediate distributing frame, market group or other separately identifiable... composed of an electronic analog or digital host office and all of its remote locations. A host/remote...
VESL: Vocational English as a Second Language. Focus: Electronics.
ERIC Educational Resources Information Center
Scales, Virginia
These instructional materials are designed to help non-English speaking students in electronics classes to improve their knowledge of English. Covered in the six units are the following topics: safety, hand tools, measuring electricity, component identification, component function, and basic soldering. The lessons include readings, vocabulary…
DOT National Transportation Integrated Search
2007-06-01
This report describes a study designed to address four research questions about symbology for electronic displays of charting information. The main research question was whether pilots could identify a set of test symbols. Three other research questi...
Identification of corn fields using multidate radar data
NASA Technical Reports Server (NTRS)
Shanmugan, K. S.; Ulaby, F. T.; Narayanan, V.; Dobson, C.
1983-01-01
Airborne C- and L-band radar data acquired over a test site in western kansas were analyzed to determine corn-field identification accuracies obtainable using single-channel, multichannel, and multidate radar data. An automated pattern-recognition procedure was used to classify 144 fields into three categories: corn, pasture land, and bare soil (including wheat stubble and fallow). Corn fields were identified with accuracies ranging from 85 percent for single channel, single-date data to 100 percent for single-channel, multidate data. The effects of radar parameters such as frequency, polarization, and look angle as well as the effects of soil moisture on the classification accuracy are also presented.
Hemispheric specialization in quantification processes.
Pasini, M; Tessari, A
2001-01-01
Three experiments were carried out to study hemispheric specialization for subitizing (the rapid enumeration of small patterns) and counting (the serial quantification process based on some formal principles). The experiments consist of numerosity identification of dot patterns presented in one visual field, with a tachistoscopic technique, or eye movements monitored through glasses, and comparison between centrally presented dot patterns and lateralized tachistoscopically presented digits. Our experiments show left visual field advantage in the identification and comparison tasks in the subitizing range, whereas right visual field advantage has been found in the comparison task for the counting range.
Interaction of an electron with coherent dipole radiation: Role of convergence and anti-dephasing
NASA Astrophysics Data System (ADS)
Robinson, A. P. L.; Arefiev, A. V.
2018-05-01
The impact of longitudinal electric fields that are present in intense focusing and defocusing electromagnetic pulses on electron acceleration is investigated. These fields are typically much weaker than the transverse fields, but it is shown that they can have a profound effect on electron energy gain. It is shown that the longitudinal electric field of a defocusing pulse is directed backward along the trajectory of an accelerated electron, which leads to a continuous net energy gain. At the same time, the effect of the transverse oscillating electric field in a defocusing pulse is to reduce the electron energy over multiple oscillations. In contrast to a well-known interaction with a plane wave, the electron is able to retain a substantial amount of energy following its interaction with a defocusing pulse. The roles of the transverse and longitudinal electric fields are reversed in a focusing pulse, which leads to a reduction in the energy retention. The present analysis underscores the importance of relatively weak oscillating electric fields in focusing and defocusing pulses.
Observations of ionospheric electron beams in the plasma sheet.
Zheng, H; Fu, S Y; Zong, Q G; Pu, Z Y; Wang, Y F; Parks, G K
2012-11-16
Electrons streaming along the magnetic field direction are frequently observed in the plasma sheet of Earth's geomagnetic tail. The impact of these field-aligned electrons on the dynamics of the geomagnetic tail is however not well understood. Here we report the first detection of field-aligned electrons with fluxes increasing at ~1 keV forming a "cool" beam just prior to the dissipation of energy in the current sheet. These field-aligned beams at ~15 R(E) in the plasma sheet are nearly identical to those commonly observed at auroral altitudes, suggesting the beams are auroral electrons accelerated upward by electric fields parallel (E([parallel])) to the geomagnetic field. The density of the beams relative to the ambient electron density is δn(b)/n(e)~5-13% and the current carried by the beams is ~10(-8)-10(-7) A m(-2). These beams in high β plasmas with large density and temperature gradients appear to satisfy the Bohm criteria to initiate current driven instabilities.
Attosecond control of electron beams at dielectric and absorbing membranes
NASA Astrophysics Data System (ADS)
Morimoto, Yuya; Baum, Peter
2018-03-01
Ultrashort electron pulses are crucial for time-resolved electron diffraction and microscopy of the fundamental light-matter interaction. In this work, we study experimentally and theoretically the generation and characterization of attosecond electron pulses by optical-field-driven compression and streaking at dielectric or absorbing interaction elements. The achievable acceleration and deflection gradient depends on the laser-electron angle, the laser's electric and magnetic field directions, and the foil orientation. Electric and magnetic fields have similar contributions to the final effect and both need to be considered. Experiments and theory agree well and reveal the optimum conditions for highly efficient, velocity-matched electron-field interactions in the longitudinal or transverse direction. We find that metallic membranes are optimum for light-electron control at mid-infrared or terahertz wavelengths, but dielectric membranes are excellent in the visible and near-infrared regimes and are therefore ideal for the formation of attosecond electron pulses.
Semiconductor quantum well irradiated by a two-mode electromagnetic field as a terahertz emitter
NASA Astrophysics Data System (ADS)
Mandal, S.; Liew, T. C. H.; Kibis, O. V.
2018-04-01
We study theoretically the nonlinear optical properties of a semiconductor quantum well (QW) irradiated by a two-mode electromagnetic wave consisting of a strong resonant dressing field and a weak off-resonant driving field. In the considered strongly coupled electron-field system, the dressing field opens dynamic Stark gaps in the electron energy spectrum of the QW, whereas the driving field induces electron oscillations in the QW plane. Since the gapped electron spectrum restricts the amplitude of the oscillations, the emission of a frequency comb from the QW appears. Therefore, the doubly driven QW operates as a nonlinear optical element which can be used, particularly, for optically controlled generation of terahertz radiation.
NASA Technical Reports Server (NTRS)
Kahler, S.; Lin, R. P.
1994-01-01
The determination of the polarities of interplanetary magnetic fields (whether the field direction is outward from or inward toward the sun) has been based on a comparison of observed field directions with the nominal Parker spiral angle. These polarities can be mapped back to the solar source field polarities. This technique fails when field directions deviate substantially from the Parker angle or when fields are substantially kinked. We introduce a simple new technique to determine the polarities of interplanetary fields using E greater than 2 keV interplanetary electrons which stream along field lines away from the sun. Those electrons usually show distinct unidirectional pitch-angle anisotropies either parallel or anti-parallel to the field. Since the electron flow direction is known to be outward from the sun, the anisotropies parallel to the field indicate outward-pointing, positive-polarity fields, and those anti-parallel indicate inward-pointing, negative-polarity fields. We use data from the UC Berkeley electron experiment on the International Sun Earth Explorer 3 (ISSE-3) spacecraft to compare the field polarities deduced from the electron data, Pe (outward or inward), with the polarities inferred from field directions, Pd, around two sector boundaries in 1979. We show examples of large (greater than 100 deg) changes in azimuthal field direction Phi over short (less than 1 hr) time scales, some with and some without reversals in Pe. The latter cases indicate that such large directional changes can occur in unipolar structures. On the other hand, we found an example of a change in Pe during which the rotation in Phi was less than 30 deg, indicating polarity changes in nearly unidirectional structures. The field directions are poor guides to the polarities in these cases.
Electron emission phenomena controlled by a transverse electric field in compound emitters
NASA Astrophysics Data System (ADS)
Olesik, Jadwiga; Calusinski, Bogdan; Olesik, Zygmunt
1996-09-01
Influence of an inner electric field on such emission phenomena like: secondary emission, photoemission and field emission has been investigated. The applied sample-emitter was a glass wafer (thickness 0.2 mm) covered on both sides by semiconducting films In2O3:Sn. A voltage (in the interval -2000V divided by 0V) generating transverse electric field was applied to one of the films. This film had a thickness of about 200 nm. The second film (emitting electrons) had a thickness 100 nm or 10 nm. The secondary emission measurements were made by the retarding field method using four grid retarding potential analyzer. It was found that the secondary emission coefficient changes non- monotonically with increasing field intensity. Electron emission measurements without using a primary electron beam were made with the electron multiplier cooperating with a multichannel pulse amplitude analyzer. The measurements were performed in the vacuum of about 2 multiplied by 10-6 Pa. Influence of film thickness on the intensity of field controlled emission and field controlled photoemission was also studied. It was also found that the frequency of counts (generated by electrons in the electron multiplier) depends on the polarizing voltage approximately in an exponential way. Some departures from this dependence can be observed at higher Upol voltages (above 1000 V). Thus, at an appropriate high voltage Upol conditions for a cascade emission are created. At lower voltages the conditions correspond to a semiconductor with a negative electron affinity.
Deployment of spatial attention to words in central and peripheral vision.
Ducrot, Stéphanie; Grainger, Jonathan
2007-05-01
Four perceptual identification experiments examined the influence of spatial cues on the recognition of words presented in central vision (with fixation on either the first or last letter of the target word) and in peripheral vision (displaced left or right of a central fixation point). Stimulus location had a strong effect on word identification accuracy in both central and peripheral vision, showing a strong right visual field superiority that did not depend on eccentricity. Valid spatial cues improved word identification for peripherally presented targets but were largely ineffective for centrally presented targets. Effects of spatial cuing interacted with visual field effects in Experiment 1, with valid cues reducing the right visual field superiority for peripherally located targets, but this interaction was shown to depend on the type of neutral cue. These results provide further support for the role of attentional factors in visual field asymmetries obtained with targets in peripheral vision but not with centrally presented targets.
Decaro, Nicola; Martella, Vito; Elia, Gabriella; Desario, Costantina; Campolo, Marco; Buonavoglia, Domenico; Bellacicco, Anna Lucia; Tempesta, Maria; Buonavoglia, Canio
2006-12-01
TaqMan-based diagnostic tests have been developed for the identification of canine parvovirus type 2 (CPV-2) strains in the faeces of dogs with diarrhoea, including a minor groove binder (MGB) probe assay for identification of type 2-based vaccines and field strains (types 2a, 2b and 2c). Since type 2b vaccines have been licensed recently in Europe, two novel MGB assays were developed for discrimination between type 2b vaccines and field strains of CPV. Such assays have been found to be highly sensitive, specific and reproducible, allowing for simultaneous detection of type 2b vaccinal and field strains present in the same specimens. These new assays will help resolution of the diagnostic problems related to the detection of a type 2b strain in the faeces of dogs shortly after the administration of a type 2b vaccine.
DE 1 observations of type 1 counterstreaming electrons and field-aligned currents
NASA Technical Reports Server (NTRS)
Lin, C. S.; Burch, J. L.; Barfield, J. N.; Sugiura, M.; Nielsen, E.
1984-01-01
Dynamics Explorer 1 satellite observations of plasma and magnetic fields during type one counterstreaming electron events are presented. Counterstreaming electrons are observed at high altitudes in the region of field-aligned current. The total current density computed from the plasma data in the 18-10,000 eV energy range is generally about 1-2 micro-A/sq m. For the downward current, low-energy electrons contribute more than 40 percent of the total plasma current density integrated above 18 eV. For the upward current, such electrons contribute less than 50 percent of that current density. Electron beams in the field-aligned direction are occasionally detected. The pitch angle distributions of counterstreaming electrons are generally enhanced at both small and large pitch angles. STARE simultaneous observations for one DE 1 pass indicated that the field-aligned current was closed through Pedersen currents in the ionosphere. The directions of the ionospheric current systems are consistent with the DE 1 observations at high altitudes.
NASA Technical Reports Server (NTRS)
Lavraud, B.; Zhang, Y. C.; Vernisse, Y.; Gershman, D. J.; Dorelli, J.; Cassak, P. A.; Dargent, J.; Pollock, C.; Giles, B.; Aunai, N.;
2016-01-01
Based on high-resolution measurements from NASA's Magnetospheric Multlscale mission, we present the dynamics of electrons associated with current systems observed near the diffusion region of magnetic reconnection at Earth's magnetopause. Using pitch angle distributions (PAD) and magnetic curvature analysis, we demonstrate the occurrence of electron scattering in the curved magnetic field of the diffusion region down to energies of 20eV. We show that scattering occurs closer to the current sheet as the electron energy decreases. The scattering of Inflowing electrons, associated with field-aligned electrostatic potentials and Hall currents, produces a new population of scattered electrons with broader PAD which bounce back and forth in the exhaust. Except at the center of the diffusion region the two populations are collocated and appear to behave adiabatically: the inflowing electron PAD focuses inward (toward lower magnetic field), while the bouncing population PAD gradually peaks at 90 degrees away from the center (where it mirrors owing to higher magnetic field and probable field-aligned potentials).
Specificity Bio-identification of CNT-Based Transistor
NASA Astrophysics Data System (ADS)
Wang, Sheng-Yu; Wu, Hue-Min
2017-12-01
In this research, we report a simple and general approach to π-π stacking functionalization of the sidewalls of CNTs by 1-pyrenebutanoic acid, succinimidyl ester (PSE), and subsequent immobilization of insulin-like growth factor 1 receptor (IGF1R) onto SWNTs with a high degree of control and specificity. The selection of PSE provides visualization and characterization of individual CNTs based on its strong luminescence. In addition, we designed a simple and efficient electrode with a staggered pattern to increase the effect of electrophoresis by using electric field for the macroscopic alignment of CNTs to complete a field-effect device for CNT-based biosensors. Scanning Electron Microscopy (SEM) was used to investigate the morphology of the biosensors. The results of four-point probe method demonstrated high selectivity and sensitivity of detection. The functionalization of SWNTs was investigated by Fourier transform infrared spectroscopy (FTIR). Experimental results imply that specific binding between IGF1R and its specific mAb results in a dramatic change in electrical current of CNT-based devices, and suggest that the devices are very promising biosensor candidates to detect circulating cancer cells.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Q.; Nelson, C. T.; Hsu, S. -L.
Flexoelectricity refers to electric polarization generated by heterogeneous mechanical strains, namely strain gradients, in materials of arbitrary crystal symmetries. Despite more than 50 years of work on this effect, an accurate identification of its coupling strength remains an experimental challenge for most materials, which impedes its wide recognition. Here, we show the presence of flexoelectricity in the recently discovered polar vortices in PbTiO 3 /SrTiO 3 superlattices based on a combination of machine-learning analysis of the atomic-scale electron microscopy imaging data and phenomenological phase-field modeling. By scrutinizing the influence of flexocoupling on the global vortex structure, we match theory andmore » experiment using computer vision methodologies to determine the flexoelectric coefficients for PbTiO 3 and SrTiO 3. Here, our findings highlight the inherent, nontrivial role of flexoelectricity in the generation of emergent complex polarization morphologies and demonstrate a viable approach to delineating this effect, conducive to the deeper exploration of both topics.« less
Li, Q.; Nelson, C. T.; Hsu, S. -L.; ...
2017-11-13
Flexoelectricity refers to electric polarization generated by heterogeneous mechanical strains, namely strain gradients, in materials of arbitrary crystal symmetries. Despite more than 50 years of work on this effect, an accurate identification of its coupling strength remains an experimental challenge for most materials, which impedes its wide recognition. Here, we show the presence of flexoelectricity in the recently discovered polar vortices in PbTiO 3 /SrTiO 3 superlattices based on a combination of machine-learning analysis of the atomic-scale electron microscopy imaging data and phenomenological phase-field modeling. By scrutinizing the influence of flexocoupling on the global vortex structure, we match theory andmore » experiment using computer vision methodologies to determine the flexoelectric coefficients for PbTiO 3 and SrTiO 3. Here, our findings highlight the inherent, nontrivial role of flexoelectricity in the generation of emergent complex polarization morphologies and demonstrate a viable approach to delineating this effect, conducive to the deeper exploration of both topics.« less
Liu, Ying; Lita, Lucian Vlad; Niculescu, Radu Stefan; Mitra, Prasenjit; Giles, C Lee
2008-11-06
Owing to new advances in computer hardware, large text databases have become more prevalent than ever.Automatically mining information from these databases proves to be a challenge due to slow pattern/string matching techniques. In this paper we present a new, fast multi-string pattern matching method based on the well known Aho-Chorasick algorithm. Advantages of our algorithm include:the ability to exploit the natural structure of text, the ability to perform significant character shifting, avoiding backtracking jumps that are not useful, efficiency in terms of matching time and avoiding the typical "sub-string" false positive errors.Our algorithm is applicable to many fields with free text, such as the health care domain and the scientific document field. In this paper, we apply the BSS algorithm to health care data and mine hundreds of thousands of medical concepts from a large Electronic Medical Record (EMR) corpora simultaneously and efficiently. Experimental results show the superiority of our algorithm when compared with the top of the line multi-string matching algorithms.
Electric field effect in multilayer Cr2Ge2Te6: a ferromagnetic 2D material
NASA Astrophysics Data System (ADS)
Xing, Wenyu; Chen, Yangyang; Odenthal, Patrick M.; Zhang, Xiao; Yuan, Wei; Su, Tang; Song, Qi; Wang, Tianyu; Zhong, Jiangnan; Jia, Shuang; Xie, X. C.; Li, Yan; Han, Wei
2017-06-01
The emergence of two-dimensional (2D) materials has attracted a great deal of attention due to their fascinating physical properties and potential applications for future nano-electronic devices. Since the first isolation of graphene, a Dirac material, a large family of new functional 2D materials have been discovered and characterized, including insulating 2D boron nitride, semiconducting 2D transition metal dichalcogenides and black phosphorus, and superconducting 2D bismuth strontium calcium copper oxide, molybdenum disulphide and niobium selenide, etc. Here, we report the identification of ferromagnetic thin flakes of Cr2Ge2Te6 (CGT) with thickness down to a few nanometers, which provides a very important piece to the van der Waals structures consisting of various 2D materials. We further demonstrate the giant modulation of the channel resistance of 2D CGT devices via electric field effect. Our results illustrate the gate voltage tunability of 2D CGT and the potential of CGT, a ferromagnetic 2D material, as a new functional quantum material for applications in future nanoelectronics and spintronics.
Antonious, George F; Turley, Eric T; Abubakari, Mutari; Snyder, John C
2017-04-03
The persistence and fate of chlorpyrifos and its two metabolites, chlorpyrifos-oxon and the 3, 5, 6-trichloro-2-pyridinol (TCP) break-down product were investigated on kale and collard leaves under field conditions. A simultaneous extraction and quantification procedure was developed for chrorpyrifos and its two main metabolites. Residues of chlorpyrifos, chlorpyrifos oxon, and TCP were determined using a gas chromatograph (GC) equipped with an electron capture detector (GC/ECD). Chlorpyrifos metabolites were detectable up to 23 days following application. Residues were confirmed using a GC equipped with a mass selective detector (GC/MSD) in total ion mode. Initial residues of chlorpyrifos were greater on collard (14.5 µg g -1 ) than kale (8.2 µg g -1 ) corresponding to half-lives (T 1/2 ) values of 7.4 and 2.2 days, respectively. TCP, the hydrolysis product, was more persistent on collards with an estimated T 1/2 of 6.5 days compared to kale (T 1/2 of 1.9 days).
Checker Takes the Guesswork out of Diode Identification
ERIC Educational Resources Information Center
Harman, Charles
2011-01-01
At technical colleges and secondary-level tech schools, students enrolled in basic electronics labs who have learned about diodes that do rectification are used to seeing power diodes like the 1N4001. When the students are introduced to low-power zener diodes and signal diodes, component identification gets more complex. If the small zeners are…
Evaluating common de-identification heuristics for personal health information.
El Emam, Khaled; Jabbouri, Sam; Sams, Scott; Drouet, Youenn; Power, Michael
2006-11-21
With the growing adoption of electronic medical records, there are increasing demands for the use of this electronic clinical data in observational research. A frequent ethics board requirement for such secondary use of personal health information in observational research is that the data be de-identified. De-identification heuristics are provided in the Health Insurance Portability and Accountability Act Privacy Rule, funding agency and professional association privacy guidelines, and common practice. The aim of the study was to evaluate whether the re-identification risks due to record linkage are sufficiently low when following common de-identification heuristics and whether the risk is stable across sample sizes and data sets. Two methods were followed to construct identification data sets. Re-identification attacks were simulated on these. For each data set we varied the sample size down to 30 individuals, and for each sample size evaluated the risk of re-identification for all combinations of quasi-identifiers. The combinations of quasi-identifiers that were low risk more than 50% of the time were considered stable. The identification data sets we were able to construct were the list of all physicians and the list of all lawyers registered in Ontario, using 1% sampling fractions. The quasi-identifiers of region, gender, and year of birth were found to be low risk more than 50% of the time across both data sets. The combination of gender and region was also found to be low risk more than 50% of the time. We were not able to create an identification data set for the whole population. Existing Canadian federal and provincial privacy laws help explain why it is difficult to create an identification data set for the whole population. That such examples of high re-identification risk exist for mainstream professions makes a strong case for not disclosing the high-risk variables and their combinations identified here. For professional subpopulations with published membership lists, many variables often needed by researchers would have to be excluded or generalized to ensure consistently low re-identification risk. Data custodians and researchers need to consider other statistical disclosure techniques for protecting privacy.
Evaluating Common De-Identification Heuristics for Personal Health Information
Jabbouri, Sam; Sams, Scott; Drouet, Youenn; Power, Michael
2006-01-01
Background With the growing adoption of electronic medical records, there are increasing demands for the use of this electronic clinical data in observational research. A frequent ethics board requirement for such secondary use of personal health information in observational research is that the data be de-identified. De-identification heuristics are provided in the Health Insurance Portability and Accountability Act Privacy Rule, funding agency and professional association privacy guidelines, and common practice. Objective The aim of the study was to evaluate whether the re-identification risks due to record linkage are sufficiently low when following common de-identification heuristics and whether the risk is stable across sample sizes and data sets. Methods Two methods were followed to construct identification data sets. Re-identification attacks were simulated on these. For each data set we varied the sample size down to 30 individuals, and for each sample size evaluated the risk of re-identification for all combinations of quasi-identifiers. The combinations of quasi-identifiers that were low risk more than 50% of the time were considered stable. Results The identification data sets we were able to construct were the list of all physicians and the list of all lawyers registered in Ontario, using 1% sampling fractions. The quasi-identifiers of region, gender, and year of birth were found to be low risk more than 50% of the time across both data sets. The combination of gender and region was also found to be low risk more than 50% of the time. We were not able to create an identification data set for the whole population. Conclusions Existing Canadian federal and provincial privacy laws help explain why it is difficult to create an identification data set for the whole population. That such examples of high re-identification risk exist for mainstream professions makes a strong case for not disclosing the high-risk variables and their combinations identified here. For professional subpopulations with published membership lists, many variables often needed by researchers would have to be excluded or generalized to ensure consistently low re-identification risk. Data custodians and researchers need to consider other statistical disclosure techniques for protecting privacy. PMID:17213047
Correlation of CVD Diamond Electron Emission with Film Properties
NASA Astrophysics Data System (ADS)
Bozeman, S. P.; Baumann, P. K.; Ward, B. L.; Nemanich, R. J.; Dreifus, D. L.
1996-03-01
Electron field emission from metals is affected by surface morphology and the properties of any dielectric coating. Recent results have demonstrated low field electron emission from p-type diamond, and photoemission measurements have identified surface treatments that result in a negative electron affinity (NEA). In this study, the field emission from diamond is correlated with surface treatment, surface roughness, and film properties (doping and defects). Electron emission measurements are reported on diamond films synthesized by plasma CVD. Ultraviolet photoemission spectroscopy indicates that the CVD films exhibit a NEA after exposure to hydrogen plasma. Field emission current-voltage measurements indicate "threshold voltages" ranging from approximately 20 to 100 V/micron.
NASA Technical Reports Server (NTRS)
Bhatia, Anand
2012-01-01
We study the free-free transition in electron-helium ion in the ground state and embedded in a Debye potential in the presence of an external laser field at very low incident electron energies. The laser field is treated classically while the collision dynamics is treated quantum mechanically. The laser field is chosen as monochromatic, linearly polarized and homogeneous. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing Volkov wave function for it. The scattering wave function for the incident electron on the target embedded in a Debye potential is solved numerically by taking into account the effect of electron exchange. We calculate the laser-assisted differential and total cross sections for free-free transition for absorption/emission of a single photon or no photon exchange. The results will be presented at the conference.
Electron dynamics in solid state via time varying wavevectors
NASA Astrophysics Data System (ADS)
Khaneja, Navin
2018-06-01
In this paper, we study electron wavepacket dynamics in electric and magnetic fields. We rigorously derive the semiclassical equations of electron dynamics in electric and magnetic fields. We do it both for free electron and electron in a periodic potential. We do this by introducing time varying wavevectors k(t). In the presence of magnetic field, our wavepacket reproduces the classical cyclotron orbits once the origin of the Schröedinger equation is correctly chosen to be center of cyclotron orbit. In the presence of both electric and magnetic fields, our equations for wavepacket dynamics differ from classical Lorentz force equations. We show that in a periodic potential, on application of electric field, the electron wave function adiabatically follows the wavefunction of a time varying Bloch wavevector k(t), with its energies suitably shifted with time. We derive the effective mass equation and discuss conduction in conductors and insulators.
MAVEN Observations of Energy-Time Dispersed Electron Signatures in Martian Crustal Magnetic Fields
NASA Technical Reports Server (NTRS)
Harada, Y.; Mitchell, D. L.; Halekas, J. S.; McFadden, J. P.; Mazelle, C.; Connerney, J. E. P.; Espley, J.; Brain, D. A.; Larson, D. E.; Lillis, R. J.;
2016-01-01
Energy-time dispersed electron signatures are observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission in the vicinity of strong Martian crustal magnetic fields. Analysis of pitch angle distributions indicates that these dispersed electrons are typically trapped on closed field lines formed above strong crustal magnetic sources. Most of the dispersed electron signatures are characterized by peak energies decreasing with time rather than increasing peak energies. These properties can be explained by impulsive and local injection of hot electrons into closed field lines and subsequent dispersion by magnetic drift of the trapped electrons. In addition, the dispersed flux enhancements are often bursty and sometimes exhibit clear periodicity, suggesting that the injection and trapping processes are intrinsically time dependent and dynamic. These MAVEN observations demonstrate that common physical processes can operate in both global intrinsic magnetospheres and local crustal magnetic fields.
Martian Dust Devil Electron Avalanche Process and Associated Electrochemistry
NASA Technical Reports Server (NTRS)
Jackson, Telana L.; Farrell, William M.; Delory, Gregory T.; Nithianandam, Jeyasingh
2010-01-01
Mars' dynamic atmosphere displays localized dust devils and larger, global dust storms. Based on terrestrial analog studies, electrostatic modeling, and laboratory work these features will contain large electrostatic fields formed via triboelectric processes. In the low-pressure Martian atmosphere, these fields may create an electron avalanche and collisional plasma due to an increase in electron density driven by the internal electrical forces. To test the hypothesis that an electron avalanche is sustained under these conditions, a self-consistent atmospheric process model is created including electron impact ionization sources and electron losses via dust absorption, electron dissociation attachment, and electron/ion recombination. This new model is called the Dust Devil Electron Avalanche Model (DDEAM). This model solves simultaneously nine continuity equations describing the evolution of the primary gaseous chemical species involved in the electrochemistry. DDEAM monitors the evolution of the electrons and primary gas constituents, including electron/water interactions. We especially focus on electron dynamics and follow the electrons as they evolve in the E field driven collisional gas. When sources and losses are self-consistently included in the electron continuity equation, the electron density grows exponentially with increasing electric field, reaching an equilibrium that forms a sustained time-stable collisional plasma. However, the character of this plasma differs depending upon the assumed growth rate saturation process (chemical saturation versus space charge). DDEAM also shows the possibility of the loss of atmospheric methane as a function of electric field due to electron dissociative attachment of the hydrocarbon. The methane destruction rates are presented and can be included in other larger atmospheric models.
Evaluation of remote sensing in control of pink bollworm in cotton. [Southern California deserts
NASA Technical Reports Server (NTRS)
Lewis, L. N. (Principal Investigator); Coleman, V. B.
1973-01-01
The author has identified the following significant results. The main objective is to evaluate the use of a satellite in monitoring the cotton production regulation program of the State of California as an aid in controlling pink bollworm infestation in the southern deserts of California. Color combined images of ERTS-1 multispectral images simulating color infrared are being used for crop identification. The status of each field (i.e., crop, bare, harvested, wet, plowed) is mapped from the imagery and is then compared to ground survey information taken at the time of ERTS-1 overflights. A computer analysis has been performed to compare field and satellite data to a crop calendar. Correlation to data has been 97% for field condition. Actual crop identification varies; cotton identification is only 63% due to lack of full season coverage.
New trend in electron holography
NASA Astrophysics Data System (ADS)
Tanigaki, Toshiaki; Harada, Ken; Murakami, Yasukazu; Niitsu, Kodai; Akashi, Tetsuya; Takahashi, Yoshio; Sugawara, Akira; Shindo, Daisuke
2016-06-01
Electron holography using a coherent electron wave is a promising technique for high-resolution visualization of electromagnetic fields in and around objects. The capability of electron holography has been enhanced by the development of new technologies and has thus become an even more powerful tool for exploring scientific frontiers. This review introduces these technologies including split-illumination electron holography and vector-field electron tomography. Split-illumination electron holography, which uses separated coherent waves, overcomes the limits imposed by the lateral coherence requirement for electron waves in electron holography. Areas that are difficult to observe using conventional electron holography are now observable. Exemplified applications include observing a singular magnetic domain wall in electrical steel sheets, local magnetizations at anti-phase boundaries, and electrostatic potentials in metal-oxide-semiconductor field-effect transistors. Vector-field electron tomography can be used to visualize magnetic vectors in three dimensions. Two components of the vectors are reconstructed using dual-axis tomography, and the remaining one is calculated using div B = 0. A high-voltage electron microscope can be used to achieve precise magnetic reconstruction. For example, magnetic vortices have been visualized using a 1 MV holography electron microscope.
Nonsequential double ionization with mid-infrared laser fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Ying -Bin; Wang, Xu; Yu, Ben -Hai
Using a full-dimensional Monte Carlo classical ensemble method, we present a theoretical study of atomic nonsequential double ionization (NSDI) with mid-infrared laser fields, and compare with results from near-infrared laser fields. Unlike single-electron strong-field processes, double ionization shows complex and unexpected interplays between the returning electron and its parent ion core. As a result of these interplays, NSDI for mid-IR fields is dominated by second-returning electron trajectories, instead of first-returning trajectories for near-IR fields. Here, some complex NSDI channels commonly happen with near-IR fields, such as the recollision-excitation-with-subsequent-ionization (RESI) channel, are virtually shut down by mid-IR fields. Besides, the finalmore » energies of the two electrons can be extremely unequal, leading to novel e-e momentum correlation spectra that can be measured experimentally.« less
Bale, S D; Mozer, F S
2007-05-18
Large parallel (
Theoretical investigation of discharge parameters in magnetized radio frequency excited CO2 lasers
NASA Astrophysics Data System (ADS)
Tavassoli, H.; Sohbatzadeh, F.; Latifi, H.
2003-06-01
In the present paper the magnetic field effects on discharge parameters in rf excited CO2 lasers are calculated. A rf generated plasma imbedded in an external, constant, and homogeneous magnetic field is considered. The continuity equation is used to derive the electron density. Quasineutrality condition and ambipolar diffusion are used. Electron attachment coefficient is neglected. Local electric field, local electron density, and thickness of charge layers are derived as a function of distance from the electrodes and magnetic field. The thickness of charge layers in the presence of magnetic field is always smaller than one without the magnetic field. When the magnetic field increases, the electron density increases in all regions of discharge, and the electric field reduces in the charge layers but increases in the middle part of discharge.
Nonsequential double ionization with mid-infrared laser fields
Li, Ying -Bin; Wang, Xu; Yu, Ben -Hai; ...
2016-11-18
Using a full-dimensional Monte Carlo classical ensemble method, we present a theoretical study of atomic nonsequential double ionization (NSDI) with mid-infrared laser fields, and compare with results from near-infrared laser fields. Unlike single-electron strong-field processes, double ionization shows complex and unexpected interplays between the returning electron and its parent ion core. As a result of these interplays, NSDI for mid-IR fields is dominated by second-returning electron trajectories, instead of first-returning trajectories for near-IR fields. Here, some complex NSDI channels commonly happen with near-IR fields, such as the recollision-excitation-with-subsequent-ionization (RESI) channel, are virtually shut down by mid-IR fields. Besides, the finalmore » energies of the two electrons can be extremely unequal, leading to novel e-e momentum correlation spectra that can be measured experimentally.« less
48 CFR 252.246-7007 - Contractor Counterfeit Electronic Part Detection and Avoidance System.
Code of Federal Regulations, 2014 CFR
2014-10-01
... chain back to the original manufacturer, whether the electronic parts are supplied as discrete...; clear identification of the name and location of supply chain intermediaries from the manufacturer to... the supply chain until such time that the parts are determined to be authentic. (7) Methodologies to...
78 FR 20175 - Proposed Collection; Comment Request for Information Collection tools.
Federal Register 2010, 2011, 2012, 2013, 2014
2013-04-03
... Form 8879-PE, IRS e-file Signature Authorization for Form 1065; Revenue Procedure 2009-32, Reliance... e-file Signature Authorization for Form 1065. OMB Number: 1545-2042. Form Number: 8879-PE. Abstract... personal identification number (PIN) to electronically sign a partnership's electronic income tax return...
19 CFR 123.92 - Electronic information for truck cargo required in advance of arrival.
Code of Federal Regulations, 2014 CFR
2014-04-01
... and exportation, in another vehicle or conveyance are also subject to the advance electronic... Vehicle Identification Number (VIN) or its license plate number and state of issuance; the equipment... number to be assigned by CBP upon the implementation of the Automated Commercial Environment); and (12...
19 CFR 123.92 - Electronic information for truck cargo required in advance of arrival.
Code of Federal Regulations, 2013 CFR
2013-04-01
... and exportation, in another vehicle or conveyance are also subject to the advance electronic... Vehicle Identification Number (VIN) or its license plate number and state of issuance; the equipment... number to be assigned by CBP upon the implementation of the Automated Commercial Environment); and (12...
49 CFR 238.305 - Interior calendar day mechanical inspection of passenger cars.
Code of Federal Regulations, 2012 CFR
2012-10-01
..., circuit breakers, contactors, relays, grid resistors, and fuses are installed in non-hazardous locations... has access to the record upon request. (2) The written or electronic record must contain the following...) Any non-complying conditions found; and (iv) The signature or electronic identification of the...
49 CFR 238.305 - Interior calendar day mechanical inspection of passenger cars.
Code of Federal Regulations, 2011 CFR
2011-10-01
..., circuit breakers, contactors, relays, grid resistors, and fuses are installed in non-hazardous locations... has access to the record upon request. (2) The written or electronic record must contain the following...) Any non-complying conditions found; and (iv) The signature or electronic identification of the...
49 CFR 238.305 - Interior calendar day mechanical inspection of passenger cars.
Code of Federal Regulations, 2013 CFR
2013-10-01
..., circuit breakers, contactors, relays, grid resistors, and fuses are installed in non-hazardous locations... has access to the record upon request. (2) The written or electronic record must contain the following...) Any non-complying conditions found; and (iv) The signature or electronic identification of the...
Generation of low-emittance electron beams in electrostatic accelerators for FEL applications
NASA Astrophysics Data System (ADS)
Chen, Teng; Elias, Luis R.
1995-02-01
This paper reports results of transverse emittance studies and beam propagation in electrostatic accelerators for free electron laser applications. In particular, we discuss emittance growth analysis of a low current electron beam system consisting of a miniature thermoionic electron gun and a National Electrostatics Accelerator (NEC) tube. The emittance growth phenomenon is discussed in terms of thermal effects in the electron gun cathode and aberrations produced by field gradient changes occurring inside the electron gun and throughout the accelerator tube. A method of reducing aberrations using a magnetic solenoidal field is described. Analysis of electron beam emittance was done with the EGUN code. Beam propagation along the accelerator tube was studied using a cylindrically symmetric beam envelope equation that included beam self-fields and the external accelerator fields which were derived from POISSON simulations.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Sha; Jones, R. R.
Electrons ejected from atoms and subsequently driven to high energies in strong laser fields enable techniques from attosecond pulse generation to imaging with rescattered electrons. Analogous processes govern strong-field electron emission from nanostructures, where long wavelength radiation and large local field enhancements hold the promise for producing electrons with substantially higher energies, allowing for higher resolution time-resolved imaging. Here we report on the use of single-cycle terahertz pulses to drive electron emission from unbiased nano-tips. Energies exceeding 5 keV are observed, substantially greater than previously attained at higher drive frequencies. Despite large differences in the magnitude of the respective localmore » fields, we find that the maximum electron energies are only weakly dependent on the tip radius, for 10 nm« less
Li, Sha; Jones, R. R.
2016-11-10
Electrons ejected from atoms and subsequently driven to high energies in strong laser fields enable techniques from attosecond pulse generation to imaging with rescattered electrons. Analogous processes govern strong-field electron emission from nanostructures, where long wavelength radiation and large local field enhancements hold the promise for producing electrons with substantially higher energies, allowing for higher resolution time-resolved imaging. Here we report on the use of single-cycle terahertz pulses to drive electron emission from unbiased nano-tips. Energies exceeding 5 keV are observed, substantially greater than previously attained at higher drive frequencies. Despite large differences in the magnitude of the respective localmore » fields, we find that the maximum electron energies are only weakly dependent on the tip radius, for 10 nm« less
A novel electron accelerator for MRI-Linac radiotherapy.
Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca
2016-03-01
MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility.
A novel electron accelerator for MRI-Linac radiotherapy
Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca
2016-01-01
Purpose: MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Methods: Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. Results: For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Conclusions: Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility. PMID:26936713
Ion Densities in the Nightside Ionosphere of Mars: Effects of Electron Impact Ionization
NASA Astrophysics Data System (ADS)
Girazian, Z.; Mahaffy, P.; Lillis, R. J.; Benna, M.; Elrod, M.; Fowler, C. M.; Mitchell, D. L.
2017-11-01
We use observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission to show how superthermal electron fluxes and crustal magnetic fields affect ion densities in the nightside ionosphere of Mars. We find that due to electron impact ionization, high electron fluxes significantly increase the CO2+, O+, and O2+ densities below 200 km but only modestly increase the NO+ density. High electron fluxes also produce distinct peaks in the CO2+, O+, and O2+ altitude profiles. We also find that superthermal electron fluxes are smaller near strong crustal magnetic fields. Consequently, nightside ion densities are also smaller near strong crustal fields because they decay without being replenished by electron impact ionization. Furthermore, the NO+/O2+ ratio is enhanced near strong crustal fields because, in the absence of electron impact ionization, O2+ is converted into NO+ and not replenished. Our results show that electron impact ionization is a significant source of CO2+, O+, and O2+ in the nightside ionosphere of Mars.
Local electric field direct writing – Electron-beam lithography and mechanism
Jiang, Nan; Su, Dong; Spence, John C. H.
2017-08-24
Local electric field induced by a focused electron probe in silicate glass thin films is evaluated in this paper by the migration of cations. Extremely strong local electric fields can be obtained by the focused electron probe from a scanning transmission electron microscope. As a result, collective atomic displacements occur. This newly revised mechanism provides an efficient tool to write patterned nanostructures directly, and thus overcome the low efficiency of the conventional electron-beam lithography. Applying this technique to silicate glass thin films, as an example, a grid of rods of nanometer dimension can be efficiently produced by rapidly scanning amore » focused electron probe. This nanopatterning is achieved through swift phase separation in the sample, without any post-development processes. The controlled phase separation is induced by massive displacements of cations (glass modifiers) within the glass-former network, driven by the strong local electric fields. The electric field is induced by accumulated charge within the electron probed region, which is generated by the excitation of atomic electrons by the incident electron. Throughput is much improved compared to other scanning probe techniques. Finally, the half-pitch spatial resolution of nanostructure in this particular specimen is 2.5 nm.« less
Local electric field direct writing – Electron-beam lithography and mechanism
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jiang, Nan; Su, Dong; Spence, John C. H.
Local electric field induced by a focused electron probe in silicate glass thin films is evaluated in this paper by the migration of cations. Extremely strong local electric fields can be obtained by the focused electron probe from a scanning transmission electron microscope. As a result, collective atomic displacements occur. This newly revised mechanism provides an efficient tool to write patterned nanostructures directly, and thus overcome the low efficiency of the conventional electron-beam lithography. Applying this technique to silicate glass thin films, as an example, a grid of rods of nanometer dimension can be efficiently produced by rapidly scanning amore » focused electron probe. This nanopatterning is achieved through swift phase separation in the sample, without any post-development processes. The controlled phase separation is induced by massive displacements of cations (glass modifiers) within the glass-former network, driven by the strong local electric fields. The electric field is induced by accumulated charge within the electron probed region, which is generated by the excitation of atomic electrons by the incident electron. Throughput is much improved compared to other scanning probe techniques. Finally, the half-pitch spatial resolution of nanostructure in this particular specimen is 2.5 nm.« less
Secure Identifications of the Electron Diffusion Region with Spacecraft Observations
NASA Astrophysics Data System (ADS)
Scudder, J. D.; Karimabadi, H.; Daughton, W. S.
2009-12-01
The Electron Diffusion Region (EDR) plays a key role in the reconnection process and its detection in spacecraft data is one of the major goals of MMS. However, the observable and diagnostic properties of entry into the EDR of collisionless magnetic reconnection remain a matter of much debate. There are also even some theoretical disagreements as to how to define secondary and tertiary properties of the EDR, that may be the only properties that are practically observable. Here we start with first principles of what the EDR is in a general magnetic topology including anti-parallel and guide field regimes. We motivate the EDR as the site in the reconnection layer where magnetic flux is not preserved for the comoving electron observer. Observable diagnostics were then found based on kinetic theory that (i) can be measured in the data, and (ii) that also highlight the theoretically motivated EDR found in the PIC simulations. We compare and contrast our diagnostics with those used by others. We present results from PIC simulations of an RD, an EDR layer, and a fast shock to illustrate their degeneracy under evidence presented in the literature to support EDR “sightings”. Seven (7) properties are shared by these layers. Invariably one of these seven inspecific tests are invoked in the literature when “EDR’s” are identified. A particularly common inspecific test is any and all violations of the Ideal Electron MHD (IEMHD) condition: E+UexB=0, whether from parallel E field detection or perpendicular deviations from IEMHD=0. PIC simulations clearly show that all three current layers possess violations of the ideal electron MHD condition; this result implies that the common usage of violations of IEMHD=0 to define, identify or corroborate a current layer as the EDR are not theoretically appropriate. Our kinetic, observable diagnostics however do differentiate amongst this degenerate class of propagating current layers. For example, these observables clearly differentiate a freely propagating RD - Alfven wave from an EDR layer, although both degenerately would satisfy the Walen test performed with electron flow and magnetic variables. We also show that the first principles definition of the EDR only selects the EDR layers from amongst this degenerate set of current layers.
MILITARY RATIONS, *MICROORGANISMS), (*FOOD, *BIOLOGICAL CONTAMINATION), DETECTION, IDENTIFICATION, STORAGE, PROCESSING, FREEZE DRYING, MICROCOCCUS , STREPTOCOCCUS, YEASTS, MOLDS(ORGANISMS), TEMPERATURE, HIGH ALTITUDE
Deficiencies of active electronic radiation protection dosimeters in pulsed fields.
Ankerhold, U; Hupe, O; Ambrosi, P
2009-07-01
Nowadays nearly all radiation fields used for X-ray diagnostics are pulsed. These fields are characterised by a high dose rate during the pulse and a short pulse duration in the range of a few milliseconds. The use of active electronic dosimeters has increased in the past few years, but these types of dosimeters might possibly not measure reliably in pulsed radiation fields. Not only personal dosimeters but also area dosimeters that are used mainly for dose rate measurements are concerned. These cannot be substituted by using passive dosimeter types. The characteristics of active electronic dosimeters determined in a continuous radiation field cannot be transferred to those in pulsed fields. Some provisional measurements with typical electronic dosimeters in pulsed radiation fields are presented to reveal this basic problem.
Fast and Confident: Postdicting Eyewitness Identification Accuracy in a Field Study
ERIC Educational Resources Information Center
Sauerland, Melanie; Sporer, Siegfried L.
2009-01-01
The combined postdictive value of postdecision confidence, decision time, and Remember-Know-Familiar (RKF) judgments as markers of identification accuracy was evaluated with 10 targets and 720 participants. In a pedestrian area, passers-by were asked for directions. Identifications were made from target-absent or target-present lineups. Fast…
The auroral current circuit and field-aligned currents observed by FAST
NASA Astrophysics Data System (ADS)
Elphic, R. C.; Bonnell, J. W.; Strangeway, R. J.; Kepko, L.; Ergun, R. E.; McFadden, J. P.; Carlson, C. W.; Peria, W.; Cattell, C. A.; Klumpar, D.; Shelley, E.; Peterson, W.; Moebius, E.; Kistler, L.; Pfaff, R.
FAST observes signatures of small-scale downward-going current at the edges of the inverted-V regions where the primary (auroral) electrons are found. In the winter pre-midnight auroral zone these downward currents are carried by upward flowing low- and medium-energy (up to several keV) electron beams. FAST instrumentation shows agreement between the current densities inferred from both the electron distributions and gradients in the magnetic field. FAST data taken near apogee (˜4000-km altitude) commonly show downward current magnetic field deflections consistent with the observed upward flux of ˜109 electrons cm-2 s-1, or current densities of several µA m-2. The electron, field-aligned current and electric field signatures indicate the downward currents may be associated with “black aurora” and auroral ionospheric cavities. The field-aligned voltage-current relationship in the downward current region is nonlinear.
Ion Beam Neutralization Using FEAs and Mirror Magnetic Fields
NASA Astrophysics Data System (ADS)
Nicolaescu, Dan; Sakai, Shigeki; Gotoh, Yasuhito; Ishikawa, Junzo
2011-01-01
Advanced implantation systems used for semiconductor processing require transportation of ion beams which are quasi-parallel and have low energy, such as (11B+,31P+,75As+) with energy in the range Eion = 200-1000 eV. Compensation of ion beam divergence may be obtained through electron injection and confinement in regions of non-uniform magnetic fields. Field emitter arrays with special properties are used as electron sources. The present study shows that electron confinement takes place in regions of gradient magnetic field, such as nearby analyzing, collimator and final energy magnets of the ion beam line. Modeling results have been obtained using Opera3D/Tosca/Scala. In regions of gradient magnetic field, electrons have helical trajectories which are confined like a cloud inside curved "magnetic bottles". An optimal range of positions with respect to the magnet for placing electron sources in gradient magnetic field has been shown to exist.
Coherent Lienard-Wiechert fields produced by free electron lasers
DOE Office of Scientific and Technical Information (OSTI.GOV)
Elias, L.R.; Gallardo, J.C.
1981-12-01
Results are presented here of a three-dimensional numerical analysis of the radiation fields produced in a free electron laser. The method used here to obtain the spatial and temporal behavior of the radiated fields is based on the coherent superposition of the exact Lienard-Wiechert fields produced by each electron in the beam. Interference effects are responsible for the narrow angular radiation patterns obtained and for the high degree of monochromaticity of the radiated field.
Nkouawa, Agathe; Sako, Yasuhito; Li, Tiaoying; Chen, Xingwang; Nakao, Minoru; Yanagida, Tetsuya; Okamoto, Munehiro; Giraudoux, Patrick; Raoul, Francis; Nakaya, Kazuhiro; Xiao, Ning; Qiu, Jiamin; Qiu, Dongchuan; Craig, Philip S; Ito, Akira
2012-12-01
In this study, we applied a loop-mediated isothermal amplification method for identification of human Taenia tapeworms in Tibetan communities in Sichuan, China. Out of 51 proglottids recovered from 35 carriers, 9, 1, and 41 samples were identified as Taenia solium, Taenia asiatica and Taenia saginata, respectively. Same results were obtained afterwards in the laboratory, except one sample. These results demonstrated that the LAMP method enabled rapid identification of parasites in the field surveys, which suggested that this method would contribute to the control of Taenia infections in endemic areas. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Zhou, Huaying; Luo, Dehan; GholamHosseini, Hamid; Li, Zhong; He, Jiafeng
2017-01-01
This paper provides a review of the most recent works in machine olfaction as applied to the identification of Chinese Herbal Medicines (CHMs). Due to the wide variety of CHMs, the complexity of growing sources and the diverse specifications of herb components, the quality control of CHMs is a challenging issue. Much research has demonstrated that an electronic nose (E-nose) as an advanced machine olfaction system, can overcome this challenge through identification of the complex odors of CHMs. E-nose technology, with better usability, high sensitivity, real-time detection and non-destructive features has shown better performance in comparison with other analytical techniques such as gas chromatography-mass spectrometry (GC-MS). Although there has been immense development of E-nose techniques in other applications, there are limited reports on the application of E-noses for the quality control of CHMs. The aim of current study is to review practical implementation and advantages of E-noses for robust and effective odor identification of CHMs. It covers the use of E-nose technology to study the effects of growing regions, identification methods, production procedures and storage time on CHMs. Moreover, the challenges and applications of E-nose for CHM identification are investigated. Based on the advancement in E-nose technology, odor may become a new quantitative index for quality control of CHMs and drug discovery. It was also found that more research could be done in the area of odor standardization and odor reproduction for remote sensing. PMID:28486407
Zhou, Huaying; Luo, Dehan; GholamHosseini, Hamid; Li, Zhong; He, Jiafeng
2017-05-09
This paper provides a review of the most recent works in machine olfaction as applied to the identification of Chinese Herbal Medicines (CHMs). Due to the wide variety of CHMs, the complexity of growing sources and the diverse specifications of herb components, the quality control of CHMs is a challenging issue. Much research has demonstrated that an electronic nose (E-nose) as an advanced machine olfaction system, can overcome this challenge through identification of the complex odors of CHMs. E-nose technology, with better usability, high sensitivity, real-time detection and non-destructive features has shown better performance in comparison with other analytical techniques such as gas chromatography-mass spectrometry (GC-MS). Although there has been immense development of E-nose techniques in other applications, there are limited reports on the application of E-noses for the quality control of CHMs. The aim of current study is to review practical implementation and advantages of E-noses for robust and effective odor identification of CHMs. It covers the use of E-nose technology to study the effects of growing regions, identification methods, production procedures and storage time on CHMs. Moreover, the challenges and applications of E-nose for CHM identification are investigated. Based on the advancement in E-nose technology, odor may become a new quantitative index for quality control of CHMs and drug discovery. It was also found that more research could be done in the area of odor standardization and odor reproduction for remote sensing.
Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.
1996-01-01
A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.
MAVEN Observations of the Effects of Crustal Magnetic Fields on the Mars Ionosphere
NASA Astrophysics Data System (ADS)
Vogt, M. F.; Flynn, C. L.; Withers, P.; Andersson, L.; Girazian, Z.; Mitchell, D. L.; Xu, S.; Connerney, J. E. P.; Espley, J. R.
2017-12-01
Mars lacks a global intrinsic magnetic field but possesses regions of strong crustal magnetic field that influence the planetary interaction with the solar wind and affect the structure and dynamics of the ionosphere. Since entering Mars orbit in 2014, the MAVEN spacecraft has collected comprehensive measurements of the local plasma and magnetic field properties in the Martian dayside ionosphere. Here we discuss how crustal magnetic fields affect the structure, composition, and electrodynamics of the Martian ionosphere as seen by MAVEN. We present a survey of 17 months of MAVEN LPW measurements of the electron density and temperature in the dayside ionosphere and show that, above 200 km altitude, regions of strong crustal magnetic fields feature cooler electron temperatures and enhanced electron densities compared to regions with little or no crustal magnetic field. We also report on the influence of the magnetic field direction and topology on MAVEN electron density measurements in the southern crustal field areas, particularly in magnetic cusp regions. Finally, we discuss the effects of crustal magnetic fields on plasma boundaries like the ionopause, located at the top of the ionosphere and marked by a sharp and substantial gradient in the electron density.
Simulated electron beam trajectories toward a field ion microscopy specimen
NASA Astrophysics Data System (ADS)
Larson, D. J.; Camus, P. P.; Kelly, T. F.
1993-04-01
This article explores the conditions under which a directed electron beam originating nearly normal to the specimen axis can be made to impact the near-apex region of a field ion microscopy specimen in a high electric field. Electron trajectories were calculated using a modified Runge-Kutta numerical method. The results indicate that an electron beam can be directed to a specimen under typical field ion microscopy conditions using two methods: by varying initial beam tilt (less than 60 mrad) or by translating the initial beam position relative to the specimen apex (less than 5 mm). The net focusing effect of the high electric field on the electron beam can be treated, to first order, as an astigmatism and may be correctable by a post-lens deflection system.