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Sample records for technology nist spectral

  1. Mass Spectral Library, NIST '02 With Windows 2.0 Software

    Science.gov (United States)

    SRD 1A NIST/EPA/NIH Mass Spectral Library, NIST '02 With Windows 2.0 Software (PC database for purchase)   Available with full-featured NIST MS Search Program for Windows integrated tools, the NIST '98 is a fully evaluated collection of electron-ionization mass spectra. (147,198 Compounds with Spectra; 147,194 Chemical Structures; 174,948 Spectra )

  2. Advances in Measurement Technology at NIST's Physical Measurement Laboratory

    Science.gov (United States)

    Dehmer, Joseph

    2014-03-01

    The NIST mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology. The Physical Measurement Laboratory (PML) has responsibility for maintaining national standards for two dozen physical quantities needed for international trade; and, importantly, it carries out advanced research at the frontiers of measurement science to enable extending innovation into new realms and new markets. This talk will highlight advances being made across several sectors of technology; and it will describe how PML interacts with its many collaborators and clients in industry, government, and academe.

  3. Activities of NIST (National Inst. of Standards and Technology)

    Science.gov (United States)

    1992-01-01

    The Radiometric Physics Division of the NIST is responsible for the national standards in radiation thermometry, spectroradiometry, photometry, and spectrophotometry; dissemination of these standards by providing measurement services to customers requiring calibrations of the highest accuracy; and conducting fundamental and applied research to develop the scientific basis for future measurement services. Its relevance to EOS/TIR calibration includes calibrating unknown blackbody for radiance using a well-characterized NIST blackbody source by matching the radiant fluxes with an IR radiometer. The TIR Round Robin is used to verify the calibration of the sources that are used for the absolute radiometric calibration of the individual EOS sensors.

  4. Characterizing Vaccinium berry Standard Reference Materials by GC-MS using NIST spectral libraries.

    Science.gov (United States)

    Lowenthal, Mark S; Andriamaharavo, Nirina R; Stein, Stephen E; Phinney, Karen W

    2013-05-01

    A gas chromatography-mass spectrometry (GC-MS)-based method was developed for qualitative characterization of metabolites found in Vaccinium fruit (berry) dietary supplement Standard Reference Materials (SRMs). Definitive identifications are provided for 98 unique metabolites determined among six Vaccinium-related SRMs. Metabolites were enriched using an organic liquid/liquid extraction, and derivatized prior to GC-MS analysis. Electron ionization (EI) fragmentation spectra were searched against EI spectra of authentic standards compiled in the National Institute of Standards and Technology's mass spectral libraries, as well as spectra selected from the literature. Metabolite identifications were further validated using a retention index match along with prior probabilities and were compared with results obtained in a previous effort using collision-induced dissociation (CID) MS/MS datasets from liquid chromatography coupled to mass spectrometry experiments. This manuscript describes a nontargeted metabolite profile of Vaccinium materials, compares results among related materials and from orthogonal experimental platforms, and discusses the feasibility and development of using mass spectral library matching for nontargeted metabolite identification.

  5. NIST Gonio-spectroradiometer

    Data.gov (United States)

    Federal Laboratory Consortium — The NIST gonio-spectroradiometer is used to measure total spectral radiant flux (TSRF) of incandescent lamps. The instrument consists of a 3-axis scanning mechanism;...

  6. The NIST Green Building Program

    Energy Technology Data Exchange (ETDEWEB)

    Hill, J.E. [National Institute of Standards and Technology (NIST), Gaithersburg, MD (United States)

    1994-12-31

    For over 2 decades, NIST has been involved in energy conservation programs. NIST`s current programs broadly span the areas from waste minimization to air, soil, water, indoor air quality, ozone depletion, and global warming. The latest endeavor NIST is undertaking is the {open_quotes}Green Building Program{close_quotes} in which NIST is at the forefront of designing buildings using environmentally safe materials. NIST`s program has two components. The laboratory-based activities involve NIST staff working directly with manufacturers and designers to develop technologies conducive to energy efficiency. The second component, demonstration buildings, includes environmentally safe buildings which are monuments to green technologies. These buildings not only demonstrate cost effectiveness and evaluate green technologies, they also identify new technologies needed to develop an effective green building.

  7. Evaluation of the sensitivity of the 'Wiley registry of tandem mass spectral data, MSforID' with MS/MS data of the 'NIST/NIH/EPA mass spectral library'.

    Science.gov (United States)

    Oberacher, Herbert; Whitley, Graeme; Berger, Bernd

    2013-04-01

    Tandem mass spectral libraries are versatile tools for small molecular identification finding application in forensic science, doping control, drug monitoring, food and environmental analysis, as well as metabolomics. Two important libraries are the 'Wiley Registry of Tandem Mass Spectral Data, MSforID' (Wiley Registry MSMS) and the collection of MS/MS spectra part of the 2011 edition of the 'NIST/NIH/EPA Mass Spectral Library' (NIST 11 MSMS). Herein, the sensitivity and robustness of the Wiley Registry MSMS were evaluated using spectra extracted from the NIST 11 MSMS library. The sample set was found to be heterogeneous in terms of mass spectral resolution, type of CID, as well as applied collision energies. Nevertheless, sensitive compound identification with a true positive identification rate ≥95% was possible using either the MSforID Search program or the NIST MS Search program 2.0g for matching. To rate the performance of the Wiley Registry MSMS, cross-validation experiments were repeated using subcollections of NIST 11 MSMS as reference library and spectra extracted from the Wiley Registry MSMS as positive controls. Unexpectedly, with both search algorithms tested, correct results were obtained in less than 88% of cases. We examined possible causes for the results of the cross validation study. The large number of precursor ions represented by a single tandem mass spectrum only was identified as the basic cause for the comparably lower sensitivity of the NIST library.

  8. Transferability of ASTM/NIST alanine-polyethylene recipe at ISS. American Society for Testing and Materials/National Institute for Standards and Technology. Istituto Superiore de Sanita

    Science.gov (United States)

    De Angelis C; Fattibene; Onori; Petetti; Bartolotta; Sansone Santamaria A

    2000-05-01

    Alanine-polyethylene solid state dosimeters were prepared at Istituto Superiore di Sanita (ISS) following the recipe proposed by National Institute of Standards and Technology (NIST) with the goal of testing its transferability. Dosimeters were prepared using 95% alanine and 5% polyethylene, by weight. They are rugged and of increased sensitivity, repeatability and reproducibility as respect to the ISS alanine-paraffin pellets. Reproducibility of about 1% was obtained at 10 Gy and at 3 Gy if one single pellet or a stack of five dosimeters were used, respectively.

  9. Atomic Spectra Bibliography Databases at NIST

    Science.gov (United States)

    Kramida, Alexander

    2008-05-01

    NIST's Atomic Spectroscopy Data Center maintains three online Bibliographic Databases (BD) containing references to papers with atomic data for controlled fusion research, modeling and diagnostics of astrophysical and terrestrial plasmas, and fundamental properties of electronic spectra of atoms and ions. The NIST Atomic Energy Levels and Spectra BD [http://physics.nist.gov/elevbib] now includes about 11500 references, mostly for years 1967--2007. The NIST Atomic Transition Probability BD, v. 8.1 [http://physics.nist.gov/fvalbib] with its 7500 references mainly covers years 1964--2007. The NIST Spectral Line Broadening BD, v. 2.0 [http://physics.nist.gov/linebrbib] has 3670 references, mostly for 1978--2006. All three databases are maintained in a unified database management system that allows us to quickly update the contents. Updates become available to users on the next day. An automated Data Entry module makes it easy to enter and categorize the data. The system allows us to keep the contents of all BDs up to date. A number of enhancements made since last year greatly increased public usability of the databases. This work is supported in part by the Office of Fusion Energy Sciences of the U.S. Department of Energy and by the National Aeronautics and Space Administration.

  10. The NIST Primary Radon-222 Measurement System

    OpenAIRE

    Collé, R.; Hutchinson, J. M. R.; Unterweger, M. P.

    1990-01-01

    Within the United States, the national standard for radon measurements is embodied in a primary radon measurement system that has been maintained for over 50 years to accurately measure radon (222Rn) against international and national radium (226Ra) standards. In turn, all of the radon measurements made at the National Institute of Standards and Technology (NIST) and the radon transfer calibration standards and calibration services provided by NIST are directly related to this national radon ...

  11. 76 FR 27305 - Proposed Information Collection; Comment Request; the NIST Summer Institute for Middle School...

    Science.gov (United States)

    2011-05-11

    ... Summer Institute for Middle School Science Teachers (NIST Summer Institute) and the NIST Research Experience for Teachers (NIST RET) Application Requirements AGENCY: National Institute of Standards and Technology (NIST), Commerce. ACTION: Notice. SUMMARY: The Department of Commerce, as part of its...

  12. High Spectral Density Optical Communication Technologies

    CERN Document Server

    Nakazawa, Masataka; Miyazaki, Tetsuya

    2010-01-01

    The latest hot topics of high-spectral density optical communication systems using digital coherent optical fibre communication technologies are covered by this book. History and meaning of a "renaissance" of the technology, requirements to the Peta-bit/s class "new generation network" are also covered in the first part of this book. The main topics treated are electronic and optical devices, digital signal processing including forward error correction, modulation formats as well as transmission and application systems. The book serves as a reference to researchers and engineers.

  13. 77 FR 18791 - Proposed Information Collection; Comment Request; NIST Associates Information System

    Science.gov (United States)

    2012-03-28

    ... National Institute of Standards and Technology Proposed Information Collection; Comment Request; NIST Associates Information System AGENCY: National Institute of Standards and Technology (NIST). ACTION: Notice... Associates Information System (NAIS) information collection instrument(s) are completed by incoming NAs. The...

  14. 76 FR 66040 - NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 2.0 (Draft...

    Science.gov (United States)

    2011-10-25

    ... National Institute of Standards and Technology NIST Framework and Roadmap for Smart Grid Interoperability... and Technology (NIST) seeks comments on the draft NIST Framework and Roadmap for Smart Grid..., 2011. The entire draft version of the NIST Framework and Roadmap for Smart Grid Interoperability...

  15. Current Status of Atomic Spectroscopy Databases at NIST

    Science.gov (United States)

    Kramida, Alexander; Ralchenko, Yuri; Reader, Joseph

    2016-05-01

    NIST's Atomic Spectroscopy Data Center maintains several online databases on atomic spectroscopy. These databases can be accessed via the http://physics.nist.gov/PhysRefData web page. Our main database, Atomic Spectra Database (ASD), recently upgraded to v. 5.3, now contains critically evaluated data for about 250,000 spectral lines and 109,000 energy levels of almost all elements in the periodic table. This new version has added several thousand spectral lines and energy levels of Sn II, Mo V, W VIII, and Th I-III. Most of these additions contain critically evaluated transition probabilities important for astrophysics, technology, and fusion research. A new feature of ASD is providing line-ratio data for diagnostics of electron temperature and density in plasmas. Saha-Boltzmann plots have been modified by adding an experimental feature allowing the user to specify a multi-element mixture. We continue regularly updating our bibliography databases, ensuring comprehensive coverage of current literature on atomic spectra for energy levels, spectral lines, transition rates, hyperfine structure, isotope shifts, Zeeman and Stark effects. Our other popular databases, such as the Handbook of Basic Atomic Spectroscopy Data, searchable atlases of spectra of Pt-Ne and Th-Ne lamps, and non-LTE plasma-kinetics code comparisons, continue to be maintained.

  16. NIST Infrared Blackbody Calibration Support for Climate Change Research

    Science.gov (United States)

    Hanssen, L. M.; Zeng, J.; Mekhontsev, S.; Khromchenko, V.

    2012-12-01

    The National Institute of Technology (NIST) Sensor Science Division has established measurement capabilities in support of various existing and planned satellite programs, which monitor key parameters for the study of climate change, such as solar irradiance, earth radiance, and atmospheric effects. These capabilities include the characterization of infrared reference blackbody sources and cavity radiometers, as well as the materials used to coat the cavity surfaces. In order to accurately measure high levels of effective emissivity and absorptance of cavities, NIST has developed a laser- and integrating-sphere-based facility (the Complete Hemispherical Infrared Laser-based Reflectometer (CHILR)). The system is used for both radiometer and blackbody cavity characterization. Multiple laser sources with wavelengths ranging from 1.5 μm to 23 μm are used to perform reflectance (1 - emissivity (or absorptance)) measurements of radiometer cavities. Measurements have been performed for numerous instruments including the Internal Calibration Target (ICT)) blackbody source used for calibration of the Cross track Infrared Sounder (CrIS), and the Total Irradiance Monitor (TIM) instrument on the Solar Radiation and Climate Experiment (SORCE), both for the Joint Polar Satellite System (JPSS), as well as the Active Cavity Radiometer Irradiance Monitor (ACRIM) instrument, and blackbodies constructed for prototyping of an infrared instrument on the Climate Absolute Radiance and Refractivity Observatory (CLARREO). For a more comprehensive understanding of the measurement results, NIST has also measured samples of the coated surfaces of the cavities and associated baffles. This includes several types of reflectance measurements: specular, directional-hemispherical (diffuse), and bi-directional distribution function (BRDF). The first two are performed spectrally and provide information that enables estimation of the cavity performance where laser sources for CHILR are not available

  17. Improved efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from the National Institute of Standards and Technology (NIST) Standard Reference Material Diesel Particulate Matter (SRM 2975) using accelerated solvent extraction.

    Science.gov (United States)

    Masala, Silvia; Ahmed, Trifa; Bergvall, Christoffer; Westerholm, Roger

    2011-12-01

    The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) with molecular masses of 252, 276, 278, 300, and 302 Da from standard reference material diesel particulate matter (SRM 2975) has been investigated using accelerated solvent extraction (ASE) with dichloromethane, toluene, methanol, and mixtures of toluene and methanol. Extraction of SRM 2975 using toluene/methanol (9:1, v/v) at maximum instrumental settings (200 °C, 20.7 MPa, and five extraction cycles) with 30-min extraction times resulted in the following elevations of the measured concentration when compared with the certified and reference concentrations reported by the National Institute of Standards and Technology (NIST): benzo[b]fluoranthene, 46%; benzo[k]fluoranthene, 137%; benzo[e]pyrene, 103%; benzo[a]pyrene, 1,570%; perylene, 37%; indeno[1,2,3-cd]pyrene, 41%; benzo[ghi]perylene, 163%; and coronene, 361%. The concentrations of the following PAHs were comparable to the reference values assigned by NIST: indeno[1,2,3-cd]fluoranthene, dibenz[a,h]anthracene, and picene. The measured concentration of dibenzo[a,e]-pyrene was lower than the information value reported by the NIST. The measured concentrations of other highly carcinogenic PAHs (dibenzo[a,l]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene) in SRM 2975 are also reported. Comparison of measurements using the optimized ASE method and using similar conditions to those applied by the NIST for the assignment of PAH concentrations in SRM 2975 indicated that the higher values obtained in the present study were associated with more complete extraction of PAHs from the diesel particulate material. Re-extraction of the particulate samples demonstrated that the deuterated internal standards were more readily recovered than the native PAHs, which may explain the lower values reported by the NIST. The analytical results obtained in the study demonstrated that the efficient extraction of PAHs from SRM 2975 is a critical requirement for the

  18. Measurement quality assurance for beta particle calibrations at NIST

    Energy Technology Data Exchange (ETDEWEB)

    Soares, C.G.; Pruitt, J.S. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

    1993-12-31

    Standardized beta-particle fields have been established in an international standard and have been adopted for use in several U.S. dosimeter and instrument testing standards. Calibration methods and measurement quality assurance procedures employed at the National Institute of Standards and Technology (NIST) for beta-particle calibrations in these reference fields are discussed. The calibration facility including the NIST-automated extrapolation ionization chamber is described, and some sample results of calibrations are shown. Methods for establishing and maintaining traceability to NIST of secondary laboratories are discussed. Currently, there are problems in finding a good method for routine testing of traceability to NIST. Some examples of past testing methods are given and solutions to this problem are proposed.

  19. 76 FR 20633 - Announcement of Meeting to Explore Feasibility of Establishing a NIST/Industry Consortium on...

    Science.gov (United States)

    2011-04-13

    ... Establishing a NIST/Industry Consortium on Neutron Measurements for Soft Materials Manufacturing AGENCY... National Institute of Standards and Technology (NIST) invites interested parties to attend a pre-consortium... industry interest in creating a NIST/industry consortium focused on advanced neutron-based probes for...

  20. Characterization of LANDSAT Panels Using the NIST BRDF Scale from 1100 nm to 2500 nm

    Science.gov (United States)

    Markham, Brian; Tsai, Benjamin K.; Allen, David W.; Cooksey, Catherine; Yoon, Howard; Hanssen, Leonard; Zeng, Jinan; Fulton, Linda; Biggar, Stuart; Markham, Brian

    2010-01-01

    Many earth observing sensors depend on white diffuse reflectance standards to derive scales of radiance traceable to the St Despite the large number of Earth observing sensors that operate in the reflective solar region of the spectrum, there has been no direct method to provide NIST traceable BRDF measurements out to 2500 rim. Recent developments in detector technology have allowed the NIST reflectance measurement facility to expand the operating range to cover the 250 nm to 2500 nm range. The facility has been modified with and additional detector using a cooled extended range indium gallium arsenide (Extended InGaAs) detector. Measurements were made for two PTFE white diffuse reflectance standards over the 1100 nm to 2500 nm region at a 0' incident and 45' observation angle. These two panels will be used to support the OLI calibration activities. An independent means of verification was established using a NIST radiance transfer facility based on spectral irradiance, radiance standards and a diffuse reflectance plaque. An analysis on the results and associated uncertainties will be discussed.

  1. Ultra-wideband spectral analysis using S2 technology

    Energy Technology Data Exchange (ETDEWEB)

    Krishna Mohan, R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)]. E-mail: krishna@spectrum.montana.edu; Chang, T. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Tian, M. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Bekker, S. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Olson, A. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Ostrander, C. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Khallaayoun, A. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Dollinger, C. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Cole, Z. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); S2 Corporation, Bozeman, MT 59718 (United States); Reibel, R.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); S2 Corporation, Bozeman, MT 59718 (United States); Merkel, K.D. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); S2 Corporation, Bozeman, MT 59718 (United States); Sun, Y. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Cone, R. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Schlottau, F. [University of Colorado, Boulder, CO 80309 (United States); Wagner, K.H. [University of Colorado, Boulder, CO 80309 (United States)

    2007-11-15

    This paper outlines the efforts to develop an ultra-wideband spectrum analyzer that takes advantage of the broad spectral response and fine spectral resolution ({approx}25 kHz) of spatial-spectral (S2) materials. The S2 material can process the full spectrum of broadband microwave transmissions, with adjustable time apertures (down to 100 {mu}s) and fast update rates (up to 1 kHz). A cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm is used as the core for the spectrum analyzer. Efforts to develop novel component technologies that enhance the performance of the system and meet the application requirements are discussed, including an end-to-end device model for parameter optimization. We discuss the characterization of new ultra-wide bandwidth S2 materials. Detection and post-processing module development including the implementation of a novel spectral recovery algorithm using field programmable gate array technology (FPGA) is also discussed.

  2. Atmospheric Sounder Spectrometer for Infrared Spectral Technology (ASSIST) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Connor J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Radiation Measurement (ARM) Program

    2016-03-01

    The Atmospheric Sounder Spectrometer for Infrared Spectral Technology (ASSIST) measures the absolute infrared (IR) spectral radiance (watts per square meter per steradian per wavenumber) of the sky directly above the instrument. More information about the instrument can be found through the manufacturer’s website. The spectral measurement range of the instrument is 3300 to 520 wavenumbers (cm-1) or 3-19.2 microns for the normal-range instruments and 3300 to 400 cm-1 or 3-25 microns, for the extended-range polar instruments. Spectral resolution is 1.0 cm-1. Instrument field-of-view is 1.3 degrees. Calibrated sky radiance spectra are produced on cycle of about 141 seconds with a group of 6 radiance spectra zenith having dwell times of about 14 seconds each interspersed with 55 seconds of calibration and mirror motion. The ASSIST data is comparable to the Atmospheric Emitted Radiance Interferometer (AERI) data and can be used for 1) evaluating line-by-line radiative transport codes, 2) detecting/quantifying cloud effects on ground-based measurements of infrared spectral radiance (and hence is valuable for cloud property retrievals), and 3) calculating vertical atmospheric profiles of temperature and water vapor and the detection of trace gases.

  3. Specular gloss scales comparison between the SIMT and the NIST

    Science.gov (United States)

    Yin, Dejin; Li, Tiecheng; Huang, Biyong; Cheng, Weihai; Lin, Fangsheng

    2016-09-01

    Specular gloss is the fraction of light reflected in the specular direction for specified incident and receptor apertures, it is the perception by an observer of the mirror-like appearance of a surface. The measurement of specular gloss consists of comparing the luminous reflectance from a test sample to that from a calibrated gloss standard which generally is a polished piece of black glass, under the same experimental conditions. Gloss is a dimensionless quantity whose accurate determination requires standardized experimental conditions such as spectral distribution of the incident beam of light, incident and viewing angles, and a gloss standard. The Shanghai Institute of Measurement and Testing Technology (SIMT) provides test service to calibrate gloss reference standards. This facility is built around a reference goniophotometer, containing an instrument that measures flux as a function of angles of illumination or observation and a primary gloss standard, which is a piece of three wedges of highly polished, high-quality optical glass. The system has an overall (k=2) uncertainty of 0.5 Gloss Unit(GU). The service offers calibration measurements of working gloss standards at the geometries of 20°, 60°, and 85°, in compliance with the ISO 2813 and the ASTM D523 documentary standards. This article describes a bilateral comparison of specular gloss scales between SIMT and the National Institute of Standards and Technology (NIST) that has been performed. The results of this comparison show agreement within the combined uncertainties for the measurement of specular gloss of highly polished black glass.

  4. Broadening the Demographics at NIST

    Science.gov (United States)

    Gebbie, Katharine B.

    2001-04-01

    Scientists have the rare privilege of earning their living by doing what they most enjoy. Women and minorities have the right, the need and the talent to compete for that privilege. And if the profession is to serve its goal of advancing, diffusing and applying the knowledge of science, it must draw upon the widest possible spectrum of talented individuals--the best and the brightest from all segments of society. This talk will discuss and evaluate efforts at NIST to ensure that women and minorities have the opportunity to participate fully in the scientific endeavor. These efforts include close collaboration with predominantly female and minority colleges; programs for students interested in pursuing advanced education; and a Summer Undergraduate Research Fellowship (SURF) program, sponsored jointly with NSF, that affords 50 students the opportunity to spend 12 weeks engaged one-on-one with NIST scientists in projects combining quests for fundamental knowledge with direct applications to problems of national importance.

  5. 75 FR 57898 - NIST Blue Ribbon Commission on Management and Safety-II

    Science.gov (United States)

    2010-09-23

    ... sector experience in one or more of the following areas: (a) Management and organizational structure; (b... National Institute of Standards and Technology NIST Blue Ribbon Commission on Management and Safety--II... establishment of the NIST Blue Ribbon Commission on Management and Safety--II and Notice of Open...

  6. NIST Calibration of a Neutron Spectrometer ROSPEC.

    Science.gov (United States)

    Heimbach, Craig

    2006-01-01

    A neutron spectrometer was acquired for use in the measurement of National Institute of Standards and Technology neutron fields. The spectrometer included options for the measurement of low and high energy neutrons, for a total measurement range from 0.01 eV up to 17 MeV. The spectrometer was evaluated in calibration fields and was used to determine the neutron spectrum of an Americium-Beryllium neutron source. The calibration fields used included bare and moderated (252)Cf, monoenergetic neutron fields of 2.5 MeV and 14 MeV, and a thermal-neutron beam. Using the calibration values determined in this exercise, the spectrometer gives a good approximation of the neutron spectrum, and excellent values for neutron fluence, for all NIST calibration fields. The spectrometer also measured an Americium-Beryllium neutron field in a NIST exposure facility and determined the field quite well. The spectrometer measured scattering effects in neutron spectra which previously could be determined only by calculation or integral measurements.

  7. 76 FR 66040 - Announcement of Meeting To Explore Feasibility of Establishing a NIST/Industry Consortium on...

    Science.gov (United States)

    2011-10-25

    ... National Institute of Standards and Technology Announcement of Meeting To Explore Feasibility of Establishing a NIST/Industry Consortium on ``Concrete Rheology: Enabling Metrology (CREME)'' AGENCY: National... Institute of Standards and Technology (NIST) invites interested parties to attend a pre-consortium...

  8. NIST Computer Scientist and Researcher Dr. Ron Ross Discusses Cybersecurity During Latest SGL

    OpenAIRE

    2010-01-01

    National Institute of Standards and Technology (NIST) senior computer scientist and information security researcher Dr. Ron Ross presented a lecture to students, staff and faculty on the new challenges in cybersecurity.

  9. NIST traceable measurements of radiance and luminance levels of night-vision-goggle test-instruments

    Science.gov (United States)

    Eppeldauer, G. P.; Podobedov, V. B.

    2014-05-01

    In order to perform radiance and luminance level measurements of night-vision-goggle (NVG) test instruments, NIST developed new-generation transfer-standard radiometers (TR). The new TRs can perform low-level radiance and luminance measurements with SI traceability and low uncertainty. The TRs were calibrated against NIST detector/radiometer standards holding the NIST photometric and radiometric scales. An 815 nm diode laser was used at NIST for the radiance responsivity calibrations. A spectrally flat (constant) filter correction was made for the TRs to correct the spectral responsivity change of the built-in Si photodiode for LEDs peaking at different wavelengths in the different test sets. The radiance responsivity transfer to the test instruments (test-sets) is discussed. The radiance values of the test instruments were measured with the TRs. The TRs propagate the traceablity to the NIST detector-based reference scales. The radiance uncertainty obtained from three TR measurements was 4.6 % (𝑘=2) at a luminance of 3.43 x 10-4 cd/m2. The output radiance of the previously used IR sphere source and the radiance responsivity of a previously used secondary standard detector unit, which was originally calibrated against an IR sphere source, were also measured with the TRs. The performances of the NVG test instruments were evaluated and the manufacturer produced radiance and luminance levels were calibrated with SI/NIST traceability.

  10. Establishment of the NIST flashing-light photometric unit

    Science.gov (United States)

    Ohno, Yoshihiro; Zong, Yuqin

    1997-09-01

    There is a need for accurate measurement of flashing lights for the proper maintenance of aircraft anticollision lights. A large variation in the measured intensities of anticollision lights has been a problem, and thus, NIST has undertaken the task to establish flashing-light photometric standards to provide calibration services in this area. A flashing-light photometric unit [lux second, (lx (DOT) s)] has been realized based on the NIST detector-based candela, using four standard photometers equipped with current integrators. Two different approaches have been taken to calibrate these standard photometers: one based on electrical calibration of the current integrator, and the other based on electronic pulsing of a steady-state photometric standard. The units realized using these two independent methods agreed to within 0.2%. The relative expanded uncertainty (k equals 2) of the standard photometers, in the measurement of the white xenon flash, is estimated to be 0.6%. The standard photometers are characterized for temporal response, linearity, and spectral responsivity, to be used for measurement of xenon flash sources of various waveforms and colors. Calibration services have been established at NIST for flashing-light photometers with white and red anticollision lights.

  11. Review of spectral imaging technology in biomedical engineering: achievements and challenges.

    Science.gov (United States)

    Li, Qingli; He, Xiaofu; Wang, Yiting; Liu, Hongying; Xu, Dongrong; Guo, Fangmin

    2013-10-01

    Spectral imaging is a technology that integrates conventional imaging and spectroscopy to get both spatial and spectral information from an object. Although this technology was originally developed for remote sensing, it has been extended to the biomedical engineering field as a powerful analytical tool for biological and biomedical research. This review introduces the basics of spectral imaging, imaging methods, current equipment, and recent advances in biomedical applications. The performance and analytical capabilities of spectral imaging systems for biological and biomedical imaging are discussed. In particular, the current achievements and limitations of this technology in biomedical engineering are presented. The benefits and development trends of biomedical spectral imaging are highlighted to provide the reader with an insight into the current technological advances and its potential for biomedical research.

  12. Emergency radiobioassay preparedness exercises through the NIST radiochemistry intercomparison program.

    Science.gov (United States)

    Nour, Svetlana; LaRosa, Jerry; Inn, Kenneth G W

    2011-08-01

    The present challenge for the international emergency radiobioassay community is to analyze contaminated samples rapidly while maintaining high quality results. The National Institute of Standards and Technology (NIST) runs a radiobioassay measurement traceability testing program to evaluate the radioanalytical capabilities of participating laboratories. The NIST Radiochemistry Intercomparison Program (NRIP) started more than 10 years ago, and emergency performance testing was added to the program seven years ago. Radiobioassay turnaround times under the NRIP program for routine production and under emergency response scenarios are 60 d and 8 h, respectively. Because measurement accuracy and sample turnaround time are very critical in a radiological emergency, response laboratories' analytical systems are best evaluated and improved through traceable Performance Testing (PT) programs. The NRIP provides participant laboratories with metrology tools to evaluate their performance and to improve it. The program motivates the laboratories to optimize their methodologies and minimize the turnaround time of their results. Likewise, NIST has to make adjustments and periodical changes in the bioassay test samples in order to challenge the participating laboratories continually. With practice, radioanalytical measurements turnaround time can be reduced to 3-4 h.

  13. NIST commitment to national MQA programs

    Energy Technology Data Exchange (ETDEWEB)

    Caswell, R.S. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

    1993-12-31

    The program of the Ionizing Radiation Division, Physics Laboratory is discussed, especially relating to standards, calibrations, and measurement quality assurance (MQA). The NIST program is {open_quotes}vertically integrated,{close_quotes} meaning that activities extend from fundamental research to measurement research to supplying services and data. Typical methods NIST uses to assure the quality of the national standards are presented. Some of the programs in x-ray, gamma-ray, electron, neutron, and radioactivity research which support MQA are presented. Examples are given of MQA activities.

  14. Improving the performance of the NIST five axis goniospectrometer for measurements of bidirectional reflectance distribution function

    Science.gov (United States)

    Podobedov, V. B.; Nadal, M. E.; Miller, C. C.

    2011-05-01

    The five axis goniospectrometer at the National Institute of Standards and Technology (NIST) measures the spectral reflectance of colored samples over a wide range of illumination and viewing angles. This capability is important for the colorimetric characterization of complex materials, such as gonioapparent coatings or retroreflective surfaces. To improve the efficiency of the goniometer, a broad-band source with a matrix-based stray-light corrected CCD based spectrometer was implemented. This new configuration offers a significant reduction in the measurement time allowing for the complete characterization of the goniodistribution of complex materials. Shorter measurement time reduces the load on the precise mechanical assembly, to ensure high angular accuracy over time. Special care was taken to extend the effective dynamic range of measured intensities in the multichannel detection mode to the values of 106 - 107 needed for the characterization of colored samples. The expanded uncertainty of the measured Bidirectional Reflectance Distribution Function (BRDF) for this new setup is about 0.5 % (k = 2) which is comparable to the uncertainty levels of the instrument operating with monochromatic illumination and a silicon photodiode. To validate the new system configuration, the measured BRDF or spectral reflectance factors (R) of test samples were compared with different instruments and we found an agreement of about 0.5 %.

  15. 77 FR 52692 - NIST Federal Information Processing Standard (FIPS) 140-3 (Second Draft), Security Requirements...

    Science.gov (United States)

    2012-08-30

    ... National Institute of Standards and Technology NIST Federal Information Processing Standard (FIPS) 140-3... sections of Federal Information Processing Standard 140-3 (Second Draft), Security Requirements for... may be sent to: Chief, Computer Security Division, Information Technology Laboratory, Attention:...

  16. NIST Gas Hydrate Research Database and Web Dissemination Channel.

    Science.gov (United States)

    Kroenlein, K; Muzny, C D; Kazakov, A; Diky, V V; Chirico, R D; Frenkel, M; Sloan, E D

    2010-01-01

    To facilitate advances in application of technologies pertaining to gas hydrates, a freely available data resource containing experimentally derived information about those materials was developed. This work was performed by the Thermodynamic Research Center (TRC) paralleling a highly successful database of thermodynamic and transport properties of molecular pure compounds and their mixtures. Population of the gas-hydrates database required development of guided data capture (GDC) software designed to convert experimental data and metadata into a well organized electronic format, as well as a relational database schema to accommodate all types of numerical and metadata within the scope of the project. To guarantee utility for the broad gas hydrate research community, TRC worked closely with the Committee on Data for Science and Technology (CODATA) task group for Data on Natural Gas Hydrates, an international data sharing effort, in developing a gas hydrate markup language (GHML). The fruits of these efforts are disseminated through the NIST Sandard Reference Data Program [1] as the Clathrate Hydrate Physical Property Database (SRD #156). A web-based interface for this database, as well as scientific results from the Mallik 2002 Gas Hydrate Production Research Well Program [2], is deployed at http://gashydrates.nist.gov.

  17. Conversion Preliminary Safety Analysis Report for the NIST Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, D. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Baek, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hanson, A. L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cheng, L-Y [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cuadra, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-01-30

    The NIST Center for Neutron Research (NCNR) is a reactor-laboratory complex providing the National Institute of Standards and Technology (NIST) and the nation with a world-class facility for the performance of neutron-based research. The heart of this facility is the NIST research reactor (aka NBSR); a heavy water moderated and cooled reactor operating at 20 MW. It is fueled with high-enriched uranium (HEU) fuel elements. A Global Threat Reduction Initiative (GTRI) program is underway to convert the reactor to low-enriched uranium (LEU) fuel. This program includes the qualification of the proposed fuel, uranium and molybdenum alloy foil clad in an aluminum alloy, and the development of the fabrication techniques. This report is a preliminary version of the Safety Analysis Report (SAR) that would be submitted to the U.S. Nuclear Regulatory Commission (NRC) for approval prior to conversion. The report follows the recommended format and content from the NRC codified in NUREG-1537, “Guidelines for Preparing and Reviewing Applications for the Licensing of Non-power Reactors,” Chapter 18, “Highly Enriched to Low-Enriched Uranium Conversions.” The emphasis in any conversion SAR is to explain the differences between the LEU and HEU cores and to show the acceptability of the new design; there is no need to repeat information regarding the current reactor that will not change upon conversion. Hence, as seen in the report, the bulk of the SAR is devoted to Chapter 4, Reactor Description, and Chapter 13, Safety Analysis.

  18. Supplemental Fingerprint Card Data (SFCD) for NIST Special Database 9

    Science.gov (United States)

    Supplemental Fingerprint Card Data (SFCD) for NIST Special Database 9 (PC database for purchase)   NIST Special Database 10 (Supplemental Fingerprint Card Data for Special Database 9 - 8-Bit Gray Scale Images) provides a larger sample of fingerprint patterns that have a low natural frequency of occurrence and transitional fingerprint classes in NIST Special Database 9. The software is the same code used with NIST Special Database 4 and 9. A newer version of the compression/decompression software on the CDROM can be found at the website http://www.nist.gov/itl/iad/ig/nigos.cfm as part of the NBIS package.

  19. Recent Developments in the NIST Atomic Databases

    Science.gov (United States)

    Kramida, Alexander

    2011-05-01

    New versions of the NIST Atomic Spectra Database (ASD, v. 4.0) and three bibliographic databases (Atomic Energy Levels and Spectra, v. 2.0, Atomic Transition Probabilities, v. 9.0, and Atomic Line Broadening and Shapes, v. 3.0) have recently been released. In this contribution I will describe the main changes in the way users get the data through the Web. The contents of ASD have been significantly extended. In particular, the data on highly ionized tungsten (W III-LXXIV) have been added from a recently published NIST compilation. The tables for Fe I and Fe II have been replaced with newer, much more extensive lists (10000 lines for Fe I). The other updated or new spectra include H, D, T, He I-II, Li I-III, Be I-IV, B I-V, C I-II, N I-II, O I-II, Na I-X, K I-XIX, and Hg I. The new version of ASD now incorporates data on isotopes of several elements. I will describe some of the issues the NIST ASD Team faces when updating the data.

  20. USCEA/NIST measurement assurance programs for the radiopharmaceutical and nuclear power industries

    Energy Technology Data Exchange (ETDEWEB)

    Golas, D.B. [Council for Energy Awareness, Washington, DC (United States)

    1993-12-31

    In cooperation with the U.S. Council for Energy Awareness (USCEA), the National Institute of Standards and Technology (NIST) supervises and administers two measurement assurance programs for radioactivity measurement traceability. One, in existence since the mid 1970s, provides traceability to suppliers of radiochemicals and radiopharmaceuticals, dose calibrators, and nuclear pharmacy services. The second program, begun in 1987, provides traceability to the nuclear power industry for utilities, source suppliers, and service laboratories. Each program is described, and the results of measurements of samples of known, but undisclosed activity, prepared at NIST and measured by the participants are presented.

  1. Assessing Customer Satisfaction at the NIST Research Library: Essential Tool for Future Planning

    Science.gov (United States)

    Liu, Rosa; Allmang, Nancy

    2008-01-01

    This article describes a campus-wide customer satisfaction survey undertaken by the National Institute of Standards and Technology (NIST) Research Library in 2007. The methodology, survey instrument, data analysis, results, and actions taken in response to the survey are described. The outcome and recommendations will guide the library both…

  2. Assessing Customer Satisfaction at the NIST Research Library: Essential Tool for Future Planning

    Science.gov (United States)

    Liu, Rosa; Allmang, Nancy

    2008-01-01

    This article describes a campus-wide customer satisfaction survey undertaken by the National Institute of Standards and Technology (NIST) Research Library in 2007. The methodology, survey instrument, data analysis, results, and actions taken in response to the survey are described. The outcome and recommendations will guide the library both…

  3. Determination of water in NIST reference material for mineral oils

    Science.gov (United States)

    Cedergren; Nordmark

    2000-07-15

    The accuracy of the reference concentrations of moisture in electrical insulating oil RM 8506 and lubricating oil RM 8507 (both of mineral type) and specified by the National Institute of Standards and Technology (NIST) as containing 39.7 and 76.8 ppm (w/w) water, respectively, has recently been the subject of debate in this journal. To shed some further light on this controversy, we report in this correspondence results for these oils obtained by two additional methods, one based on specially designed reagents for diaphragm-free Karl Fischer (KF) coulometry and the other based on the concept of stripping at elevated temperature/continuous KF coulometry. A positive interference effect was shown to take place for RM 8506 when the direct coulometric method was used. If the results are corrected for this, the values including six different procedures varied in the range 13.5-15.6 ppm (w/w). For RM 8507, all values were between 42.5 and 47.2 ppm (w/w), which means that the values recommended by NIST for both reference oils using volumetric titration are about twice as high as those obtained with the other techniques. A possible explanation for this discrepancy is presented.

  4. NIST Combinatorial Methods Center: Model for Industrial Outreach

    Science.gov (United States)

    Amis, Eric J.; Karim, Alamgir

    2002-03-01

    The measurements, standards, and test methods developed by NIST, in partnership with other organizations, often help unlock the potential of new discoveries and budding technologies. Combinatorial methods are a textbook example. These emerging tools can speed innovation in many fields - pharmaceuticals, chemistry, and, most recently, materials. In the diverse realm of materials, combinatorial methods hold promise for all classes, including metals, polymers, ceramics, and biomaterials. NIST has established the NCMC as a model for collaboration, in order to share expertise, facilities, resources, and information thereby reducing obstacles to participating in this fast-moving and instrument-intensive area. Although collaborations with multiple partners can be difficult, the goal is to foster cross-fertilization of ideas and research strategies, and to spur progress on many fronts by crossing boundaries of organizations, disciplines, and interests. Members have access to technical workshops, short courses, data libraries, and electronic bulletin boards; they can participate in non-proprietary focused projects; and they can enter into specific cooperative research and development agreements with controlled intellectual property.

  5. Experimental research on showing automatic disappearance pen handwriting based on spectral imaging technology

    Science.gov (United States)

    Su, Yi; Xu, Lei; Liu, Ningning; Huang, Wei; Xu, Xiaojing

    2016-10-01

    Purpose to find an efficient, non-destructive examining method for showing the disappearing words after writing with automatic disappearance pen. Method Using the imaging spectrometer to show the potential disappearance words on paper surface according to different properties of reflection absorbed by various substances in different bands. Results the disappeared words by using different disappearance pens to write on the same paper or the same disappearance pen to write on different papers, both can get good show results through the use of the spectral imaging examining methods. Conclusion Spectral imaging technology can show the disappearing words after writing by using the automatic disappearance pen.

  6. [Fast Detection of Camellia Sinensis Growth Process and Tea Quality Informations with Spectral Technology: A Review].

    Science.gov (United States)

    Peng, Ji-yu; Song, Xing-lin; Liu, Fei; Bao, Yi-dan; He, Yong

    2016-03-01

    The research achievements and trends of spectral technology in fast detection of Camellia sinensis growth process information and tea quality information were being reviewed. Spectral technology is a kind of fast, nondestructive, efficient detection technology, which mainly contains infrared spectroscopy, fluorescence spectroscopy, Raman spectroscopy and mass spectroscopy. The rapid detection of Camellia sinensis growth process information and tea quality is helpful to realize the informatization and automation of tea production and ensure the tea quality and safety. This paper provides a review on its applications containing the detection of tea (Camellia sinensis) growing status(nitrogen, chlorophyll, diseases and insect pest), the discrimination of tea varieties, the grade discrimination of tea, the detection of tea internal quality (catechins, total polyphenols, caffeine, amino acid, pesticide residual and so on), the quality evaluation of tea beverage and tea by-product, the machinery of tea quality determination and discrimination. This paper briefly introduces the trends of the technology of the determination of tea growth process information, sensor and industrial application. In conclusion, spectral technology showed high potential to detect Camellia sinensis growth process information, to predict tea internal quality and to classify tea varieties and grades. Suitable chemometrics and preprocessing methods is helpful to improve the performance of the model and get rid of redundancy, which provides the possibility to develop the portable machinery. Future work is to develop the portable machinery and on-line detection system is recommended to improve the further application. The application and research achievement of spectral technology concerning about tea were outlined in this paper for the first time, which contained Camellia sinensis growth, tea production, the quality and safety of tea and by-produce and so on, as well as some problems to be solved

  7. 76 FR 67418 - Request for Comments on NIST Special Publication 500-293, US Government Cloud Computing...

    Science.gov (United States)

    2011-11-01

    .... SUPPLEMENTARY INFORMATION: The National Institute of Standards and Technology (NIST) has a technology leadership role in support of a secure and effectively adopted Cloud Computing model \\1\\ to reduce costs and improve services. This role is described ] in the 2011 Federal Cloud Computing Strategy \\2\\ as ``a central...

  8. Measurement of the Microwave Lensing shift in NIST-F1 and NIST-F2

    Science.gov (United States)

    Jefferts, S. R.; Heavner, T. P.; Barlow, S. E.; Ashby, N.

    2016-06-01

    With several Primary Frequency Standards (PFS) across the world demonstrating systematic fractional frequency uncertainties on order of 1 x 10-16, it is crucial to accurately measure or model even small frequency shifts that could affect the ultimate PFS uncertainty, and thus ultimately impact the rate of Coordinated Universal Time (UTC) which relies on precision PFS measurements. Recently there has been controversy about the physical causes and size of PFS frequency shifts due to microwave lensing effects. We present here the first measurements of microwave lensing frequency shifts in the PFS NIST-F1 and NIST-F2. The measured frequency shifts agree well with the recent theory of Ashby et al [1].

  9. Re-calibration of the NIST SRM 2059 master standard using traceable atomic force microscope metrology

    Science.gov (United States)

    Dixson, Ronald; Potzick, James; Orji, Ndubuisi G.

    2008-10-01

    The current photomask linewidth Standard Reference Material (SRM) supplied by the National Institute of Standards and Technology (NIST), SRM 2059, is the fifth generation of such standards for mask metrology. An in house optical microscope tool developed at NIST, called the NIST ultra-violet (UV) microscope, was used in transmission mode to calibrate the SRM 2059 photomasks. Due to the limitations of available optical models for determining the edge response in the UV microscope, the tool was used in a comparator mode. One of the masks was selected as a master standard - and the features on this mask were calibrated using traceable critical dimension atomic force microscope (CD-AFM) dimensional metrology. The optical measurements were then used to determine the relative offsets between the widths on the master standard and individual masks for sale to customers. At the time of these measurements, however, the uncertainties in the CD-AFM reference metrology on the master standard were larger than can now be achieved because the NIST single crystal critical dimension reference material (SCCDRM) project had not been completed. Using our CD-AFM at NIST, we have performed new measurements on the SRM 2059 master standard. The new AFM results are in agreement with the prior measurements and have expanded uncertainties approximately one fourth of those of the earlier results for sub-micrometer features. When the optical comparator data for customers masks are reanalyzed using these new AFM results, we expect to reduce the combined reported uncertainties for the linewidths on the actual SRMs by at least 40 % for the nominal 0.25 μm features.

  10. [Spectral navigation technology and its application in positioning the fruits of fruit trees].

    Science.gov (United States)

    Yu, Xiao-Lei; Zhao, Zhi-Min

    2010-03-01

    An innovative technology of spectral navigation is presented in the present paper. This new method adopts reflectance spectra of fruits, leaves and branches as one of the key navigation parameters and positions the fruits of fruit trees relying on the diversity of spectral characteristics. The research results show that the distinct smoothness as effect is available in the spectrum of leaves of fruit trees. On the other hand, gradual increasing as the trend is an important feature in the spectrum of branches of fruit trees while the spectrum of fruit fluctuates. In addition, the peak diversity of reflectance rate between fruits and leaves of fruit trees is reached at 850 nm of wavelength. So the limit value can be designed at this wavelength in order to distinguish fruits and leaves. The method introduced here can not only quickly distinguish fruits, leaves and branches, but also avoid the effects of surroundings. Compared with the traditional navigation systems based on machine vision, there are still some special and unique features in the field of positioning the fruits of fruit trees using spectral navigation technology.

  11. Liquid Scintillation Counting Standardization of {sup 2}2NaCl by te CIEMAT/NIST method; Calibracion por Centelleo Liquido del ''22NaCl, mediante el metodo CIEMAT/NIST

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

    1995-07-01

    We describe a procedure for preparing a stable solution of ''22NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4 % and an overall uncertainty of 0.35 %. (Author) 4 refs.

  12. First measurements of the flux integral with the NIST-4 watt balance

    CERN Document Server

    Haddad, D; Chao, L S; Cao, A; Sineriz, G; Pratt, J R; Newell, D B; Schlamminger, S

    2015-01-01

    In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, the gravitational force of an unknown mass is compensated by an electromagnetic force produced by a coil in a magnet system. The electromagnetic force depends on the current in the coil and the magnetic flux integral. Most watt balances feature an additional calibration mode, referred to as velocity mode, which allows one to measure the magnetic flux integral to high precision. In this article we describe first measurements of the flux integral in the new watt balance. We introduce measurement and data analysis techniques to assess the quality of the measurements and the adverse effects of vibrations on the instrument.

  13. [Research on identification of cabbages and weeds combining spectral imaging technology and SAM taxonomy].

    Science.gov (United States)

    Zu, Qin; Zhang, Shui-fa; Cao, Yang; Zhao, Hui-yi; Dang, Chang-qing

    2015-02-01

    Weeds automatic identification is the key technique and also the bottleneck for implementation of variable spraying and precision pesticide. Therefore, accurate, rapid and non-destructive automatic identification of weeds has become a very important research direction for precision agriculture. Hyperspectral imaging system was used to capture the hyperspectral images of cabbage seedlings and five kinds of weeds such as pigweed, barnyard grass, goosegrass, crabgrass and setaria with the wavelength ranging from 1000 to 2500 nm. In ENVI, by utilizing the MNF rotation to implement the noise reduction and de-correlation of hyperspectral data and reduce the band dimensions from 256 to 11, and extracting the region of interest to get the spectral library as standard spectra, finally, using the SAM taxonomy to identify cabbages and weeds, the classification effect was good when the spectral angle threshold was set as 0. 1 radians. In HSI Analyzer, after selecting the training pixels to obtain the standard spectrum, the SAM taxonomy was used to distinguish weeds from cabbages. Furthermore, in order to measure the recognition accuracy of weeds quantificationally, the statistical data of the weeds and non-weeds were obtained by comparing the SAM classification image with the best classification effects to the manual classification image. The experimental results demonstrated that, when the parameters were set as 5-point smoothing, 0-order derivative and 7-degree spectral angle, the best classification result was acquired and the recognition rate of weeds, non-weeds and overall samples was 80%, 97.3% and 96.8% respectively. The method that combined the spectral imaging technology and the SAM taxonomy together took full advantage of fusion information of spectrum and image. By applying the spatial classification algorithms to establishing training sets for spectral identification, checking the similarity among spectral vectors in the pixel level, integrating the advantages of

  14. The NIST Simple Guide for Evaluating and Expressing Measurement Uncertainty

    Science.gov (United States)

    Possolo, Antonio

    2016-11-01

    NIST has recently published guidance on the evaluation and expression of the uncertainty of NIST measurement results [1, 2], supplementing but not replacing B. N. Taylor and C. E. Kuyatt's (1994) Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results (NIST Technical Note 1297) [3], which tracks closely the Guide to the expression of uncertainty in measurement (GUM) [4], originally published in 1995 by the Joint Committee for Guides in Metrology of the International Bureau of Weights and Measures (BIPM). The scope of this Simple Guide, however, is much broader than the scope of both NIST Technical Note 1297 and the GUM, because it attempts to address several of the uncertainty evaluation challenges that have arisen at NIST since the 1990s, for example to include molecular biology, greenhouse gases and climate science measurements, and forensic science. The Simple Guide also expands the scope of those two other guidance documents by recognizing observation equations (that is, statistical models) as bona fide measurement models. These models are indispensable to reduce data from interlaboratory studies, to combine measurement results for the same measurand obtained by different methods, and to characterize the uncertainty of calibration and analysis functions used in the measurement of force, temperature, or composition of gas mixtures. This presentation reviews the salient aspects of the Simple Guide, illustrates the use of models and methods for uncertainty evaluation not contemplated in the GUM, and also demonstrates the NIST Uncertainty Machine [5] and the NIST Consensus Builder, which are web-based applications accessible worldwide that facilitate evaluations of measurement uncertainty and the characterization of consensus values in interlaboratory studies.

  15. A Path to NIST Calibrated Stars over the Dome of the Sky

    Science.gov (United States)

    Zimmer, P.; McGraw, J. T.; Zirzow, D. C.; Cramer, C.; Lykke, K.; Woodward, J. T., IV

    2016-05-01

    The UNM Measurement Astrophysics group is currently constructing and testing a mobile instrument suite that includes a multi-wavelength backscatter lidar, stellar spectroradiometer and cameras (visible and thermal infrared) that will provide real-time atmospheric transmission metadata in the column of atmosphere through which a supported telescope is observing. The design , operation and calibration of the lidar (the Facility Lidar for Astronomical Measurement of Extinction - FLAME) and spectroradiometer (the Astronomical Extinction SpectroPhotometer - AESoP) are detailed. The first task of this instrument suite will be to help create a new set of standard stars radiometrically calibrated to NIST standards. Initially this will be done for bright stars across the wavelength range 350nm to 1050nm at 1nm spectral resolution with measurement accuracy better than 1% per spectral resolution element by calibration to NIST silicon detectors. Because these standard stars will support both ground- and space-based observations, our proposed evolution of calibration begins with suitable bright optical standards and then adds measurements into the infrared. Following optical/infrared calibration of bright stars we plan to calibrate fainter stars, ultimately to V˜18, both in the optical and near infrared.

  16. Scalable modulation technology and the tradeoff of reach, spectral efficiency, and complexity

    Science.gov (United States)

    Bosco, Gabriella; Pilori, Dario; Poggiolini, Pierluigi; Carena, Andrea; Guiomar, Fernando

    2017-01-01

    Bandwidth and capacity demand in metro, regional, and long-haul networks is increasing at several tens of percent per year, driven by video streaming, cloud computing, social media and mobile applications. To sustain this traffic growth, an upgrade of the widely deployed 100-Gbit/s long-haul optical systems, based on polarization multiplexed quadrature phase-shift keying (PM-QPSK) modulation format associated with coherent detection and digital signal processing (DSP), is mandatory. In fact, optical transport techniques enabling a per-channel bit rate beyond 100 Gbit/s have recently been the object of intensive R and D activities, aimed at both improving the spectral efficiency and lowering the cost per bit in fiber transmission systems. In this invited contribution, we review the different available options to scale the per-channel bit-rate to 400 Gbit/s and beyond, i.e. symbol-rate increase, use of higher-order quadrature amplitude modulation (QAM) modulation formats and use of super-channels with DSP-enabled spectral shaping and advanced multiplexing technologies. In this analysis, trade-offs of system reach, spectral efficiency and transceiver complexity are addressed. Besides scalability, next generation optical networks will require a high degree of flexibility in the transponders, which should be able to dynamically adapt the transmission rate and bandwidth occupancy to the light path characteristics. In order to increase the flexibility of these transponders (often referred to as "flexponders"), several advanced modulation techniques have recently been proposed, among which sub-carrier multiplexing, hybrid formats (over time, frequency and polarization), and constellation shaping. We review these techniques, highlighting their limits and potential in terms of performance, complexity and flexibility.

  17. Development and bench testing of a multi-spectral imaging technology built on a smartphone platform

    Science.gov (United States)

    Bolton, Frank J.; Weiser, Reuven; Kass, Alex J.; Rose, Donny; Safir, Amit; Levitz, David

    2016-03-01

    Cervical cancer screening presents a great challenge for clinicians across the developing world. In many countries, cervical cancer screening is done by visualization with the naked eye. Simple brightfield white light imaging with photo documentation has been shown to make a significant impact on cervical cancer care. Adoption of smartphone based cervical imaging devices is increasing across Africa. However, advanced imaging technologies such as multispectral imaging systems, are seldom deployed in low resource settings, where they are needed most. To address this challenge, the optical system of a smartphone-based mobile colposcopy imaging system was refined, integrating components required for low cost, portable multi-spectral imaging of the cervix. This paper describes the refinement of the mobile colposcope to enable it to acquire images of the cervix at multiple illumination wavelengths, including modeling and laboratory testing. Wavelengths were selected to enable quantifying the main absorbers in tissue (oxyand deoxy-hemoglobin, and water), as well as scattering parameters that describe the size distribution of scatterers. The necessary hardware and software modifications are reviewed. Initial testing suggests the multi-spectral mobile device holds promise for use in low-resource settings.

  18. Study on shallow groundwater information extraction technology based on multi-spectral data and spatial data

    Institute of Scientific and Technical Information of China (English)

    YU DeHao; DENG ZhengDong; LONG Fan; GUAN HongJun; WANG DaQing; GOU YiZheng

    2009-01-01

    Aimed at solving the difficulties, such as low efficiency and limited exploration range encountered in finding groundwater with the traditional methods, a new method was presented by using remote sensing technology in this paper. Based on multi-spectral data (ETM data) and spatial data (SRTM data),a forecasting model was built to produce a probability rating map for finding shallow groundwater in the arid and semi-arid areas. According to investigations, a conclusion is drawn that the results of the model are satisfied, which have been testified by the later geophysical exploration and drilling. Thus,the model can serve as a guide for finding groundwater in the arid and semi-arid regions.

  19. Study on shallow groundwater information extraction technology based on multi-spectral data and spatial data

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Aimed at solving the difficulties,such as low efficiency and limited exploration range encountered in finding groundwater with the traditional methods,a new method was presented by using remote sensing technology in this paper.Based on multi-spectral data(ETM data) and spatial data(SRTM data),a forecasting model was built to produce a probability rating map for finding shallow groundwater in the arid and semi-arid areas.According to investigations,a conclusion is drawn that the results of the model are satisfied,which have been testified by the later geophysical exploration and drilling.Thus,the model can serve as a guide for finding groundwater in the arid and semi-arid regions.

  20. The NIST eutectic project: construction of Co C, Pt C and Re C fixed-point cells and their comparison with the NMIJ

    Science.gov (United States)

    Sasajima, N.; Yoon, H. W.; Gibson, C. E.; Khromchenko, V.; Sakuma, F.; Yamada, Y.

    2006-04-01

    The National Institute of Standards and Technology (NIST) has initiated a project on novel high-temperature fixed-points by use of metal (carbide)-carbon eutectics to lower uncertainties in thermodynamic temperature measurement. As the first stage of the NIST eutectic project, a comparison of Co-C, Pt-C and Re-C eutectic fixed-point cells was conducted between the NIST and the National Metrology Institute of Japan (NMIJ) at the NIST to verify the quality of the NIST eutectic cells in addition to checking for possible furnace and radiation thermometer effects on the eutectic fixed-point realizations. In the comparison, two high-temperature furnaces, two radiation thermometers and one gold-point blackbody were used. A Nagano M furnace and a Linear Pyrometer 3 radiation thermometer were transferred from NMIJ and were used in conjunction with a Thermo Gauge furnace and an Absolute Pyrometer 1 radiation thermometer of NIST to check the dependence on the measurement equipment. The results showed that Co-C cells agreed to 73 mK. The melting temperature of the NIST Pt-C cell was approximately 270 mK lower than that of the NMIJ cell, with a comparison uncertainty of roughly 110 mK (k = 2), due to the poor purity of Pt powder. Although the Re-C comparison showed instability of the comparison system, they agreed within 100 mK. Though further improvement is necessary for the Pt-C cell, such as the use of higher purity Pt, the filling and measuring technique has been established at the NIST.

  1. NIST and NFI-TNO evaluations of automatic speaker recognition

    NARCIS (Netherlands)

    Leeuwen, D.A. van; Martin, A.F.; Przybocki, M.A.; Bouten, J.S.

    2006-01-01

    In the past years, several text-independent speaker recognition evaluation campaigns have taken place. This paper reports on results of the NIST evaluation of 2004 and the NFI-TNO forensic speaker recognition evaluation held in 2003, and reflects on the history of the evaluation campaigns. The effec

  2. NIST and NFI-TNO evaluations of automatic speaker recognition

    NARCIS (Netherlands)

    Leeuwen, D.A. van; Martin, A.F.; Przybocki, M.A.; Bouten, J.S.

    2005-01-01

    In the past years, several text-independent speaker recognition evaluation campaigns have taken place. This paper reports on results of the NIST evaluation of 2004 and the NFI-TNO forensic speaker recognition evaluation held in 2003, and re.ects on the history of the evaluation campaigns. The e.ects

  3. HAPPY Team Entry to NIST OpenSAD Challenge: A Fusion of Short-Term Unsupervised and Segment i-Vector Based Speech Activity Detectors

    DEFF Research Database (Denmark)

    Kinnunen, Tomi; Sholokhov, Alexey; Khoury, Elie;

    2016-01-01

    Speech activity detection (SAD), the task of locating speech segments from a given recording, remains challenging under acoustically degraded conditions. In 2015, National Institute of Standards and Technology (NIST) coordinated OpenSAD bench-mark. We summarize “HAPPY” team effort to Open- SAD. S...

  4. Findings and Recommendations from the NIST Workshop on Alternative Fuels and Materials: Biocorrosion.

    Science.gov (United States)

    Mansfield, Elisabeth; Sowards, Jeffrey W; Crookes-Goodson, Wendy J

    2015-01-01

    In 2013, the Applied Chemicals and Materials Division of the National Institute of Standards and Technology (NIST) hosted a workshop to identify and prioritize research needs in the area of biocorrosion. Materials used to store and distribute alternative fuels have experienced an increase in corrosion due to the unique conditions caused by the presence of microbes and the chemistry of biofuels and biofuel precursors. Participants in this workshop, including experts from the microbiological, fuel, and materials communities, delved into the unique materials and chemical challenges that occur with production, transport, and storage of alternative fuels. Discussions focused on specific problems including: a) the changing composition of "drop-in" fuels and the impact of that composition on materials; b) the influence of microbial populations on corrosion and fuel quality; and c) state-of-the-art measurement technologies for monitoring material degradation and biofilm formation.

  5. Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II

    Science.gov (United States)

    Newbury, Dale E.; Ritchie, Nicholas W. M.

    2014-09-01

    Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine returns quantitative results supported by a complete error budget, including estimates of the uncertainties from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is available free for Java-platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

  6. PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR.

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, L.; Diamond, D.; Xu, J.; Carew, J.; Rorer, D.

    2004-03-31

    Detailed reactor physics and safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron and photon transport calculations were performed with the MCNP code to determine the safety parameters for the NBSR. The core depletion and determination of the fuel compositions were performed with MONTEBURNS. MCNP calculations were performed to determine the beginning, middle, and end-of-cycle power distributions, moderator temperature coefficient, and shim safety arm, beam tube and void reactivity worths. The calculational model included a plate-by-plate description of each fuel assembly, axial mid-plane water gap, beam tubes and the tubular geometry of the shim safety arms. The time-dependent analysis of the primary loop was determined with a RELAP5 transient analysis model that includes the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. The statistical analysis used to assure protection from critical heat flux (CHF) was performed using a Monte Carlo simulation of the uncertainties contributing to the CHF calculation. The power distributions used to determine the local fuel conditions and margin to CHF were determined with MCNP. Evaluations were performed for the following accidents: (1) the control rod withdrawal startup accident, (2) the maximum reactivity insertion accident, (3) loss-of-flow resulting from loss of electrical power, (4) loss-of-flow resulting from a primary pump seizure, (5) loss-of-flow resulting from inadvertent throttling of a flow control valve, (6) loss-of-flow resulting from failure of both shutdown cooling pumps and (7) misloading of a fuel element. In both the startup and maximum reactivity insertion accidents, the

  7. 76 FR 18166 - Technology Innovation Program Advisory Board

    Science.gov (United States)

    2011-04-01

    ... National Institute of Standards and Technology Technology Innovation Program Advisory Board AGENCY.... SUMMARY: The Technology Innovation Program Advisory Board, National Institute of Standards and Technology.... Cesaro's e-mail address is rene.cesaro@nist.gov . SUPPLEMENTARY INFORMATION: The Technology...

  8. NIST Ionization Chamber “A” Sample-Height Corrections

    OpenAIRE

    Fitzgerald, Ryan

    2012-01-01

    For over 30 years scientists in the NIST radioactivity group have been using their pressurized ionization chamber “A” (PIC “A”) to make measurements of radioactivity and radioactive half-lives. We now have evidence that some of those reported measurements were incorrect due to slippage of the source positioning ring over time. The temporal change in the holder caused an error in the source-height within the chamber, which was thought to be invariant. This unaccounted-for height change caused ...

  9. Stability improvements for the NIST Yb optical lattice clock

    Science.gov (United States)

    Fasano, R. J.; Schioppo, M.; McGrew, W. F.; Brown, R. C.; Hinkley, N.; Yoon, T. H.; Beloy, K.; Oates, C. W.; Ludlow, A. D.

    2016-05-01

    To reach the fundamental limit given by quantum projection noise, optical lattice clocks require advanced laser stabilization techniques. The NIST ytterbium clock has benefited from several generations of extremely high finesse optical cavities, with cavity linewidths below 1 kHz. Characterization of the cavity drift rate has allowed compensation to the mHz/s level, improving the medium-term stability of the cavity. Based on recent measurements using Ramsey spectroscopy with synchronous interrogation, we report a fractional instability σy(1s) thermal noise floor, which will improve our Dick-limited fractional instability at 1 s to below 10-16. Also at University of Colorado.

  10. Utility of NIST Whole-Genome Reference Materials for the Technical Validation of a Multigene Next-Generation Sequencing Test.

    Science.gov (United States)

    Shum, Bennett O V; Henner, Ilya; Belluoccio, Daniele; Hinchcliffe, Marcus J

    2017-07-01

    The sensitivity and specificity of next-generation sequencing laboratory developed tests (LDTs) are typically determined by an analyte-specific approach. Analyte-specific validations use disease-specific controls to assess an LDT's ability to detect known pathogenic variants. Alternatively, a methods-based approach can be used for LDT technical validations. Methods-focused validations do not use disease-specific controls but use benchmark reference DNA that contains known variants (benign, variants of unknown significance, and pathogenic) to assess variant calling accuracy of a next-generation sequencing workflow. Recently, four whole-genome reference materials (RMs) from the National Institute of Standards and Technology (NIST) were released to standardize methods-based validations of next-generation sequencing panels across laboratories. We provide a practical method for using NIST RMs to validate multigene panels. We analyzed the utility of RMs in validating a novel newborn screening test that targets 70 genes, called NEO1. Despite the NIST RM variant truth set originating from multiple sequencing platforms, replicates, and library types, we discovered a 5.2% false-negative variant detection rate in the RM truth set genes that were assessed in our validation. We developed a strategy using complementary non-RM controls to demonstrate 99.6% sensitivity of the NEO1 test in detecting variants. Our findings have implications for laboratories or proficiency testing organizations using whole-genome NIST RMs for testing. Copyright © 2017 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  11. Experimental Progress on the NIST ^27Al^+ Optical Clock

    Science.gov (United States)

    Chou, Chin-Wen; Hume, David B.; Koelemeij, Jeroen C. J.; Rosenband, Till; Bergquist, James C.; Wineland, Dave J.

    2009-05-01

    A recent measurement of the frequency ratio between single-ion optical clocks based on ^27Al^+ and ^199Hg^+ at NIST showed a combined statistical and systematic uncertainty of 5.2 x 10-17[1]. Here we report progress on improving both the accuracy and stability of the ^27Al^+ optical clock. We have developed a new trap and laser systems that enable the use of ^25Mg^+ for sympathetic cooling and clock-state detection of ^27Al^+. These developments should reduce time-dilation shifts caused by harmonic motion of the ions and thus lower the dominant systematic uncertainty below 10-17. In the new clock apparatus we have demonstrated spectroscopy of the ^27Al^+ ^1S0 to ^3P0 transition with a quality factor of Q = 3.5 x 10^14 and simultaneously a contrast approaching unity. In addition, we have developed techniques for the sympathetic laser cooling and quantum logic spectroscopy of multiple aluminum ions with the goal of further improving measurement stability [2]. *supported by ONR and NIST [1] T. Rosenband et al., Science 319, 1808 (2008) [2] D. B. Hume et al., Phys. Rev. Lett. 99, 120502 (2007)

  12. MO-D-BRD-04: NIST Air-Kerma Standard for Electronic Brachytherapy Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Mitch, M. [Nat’l Institute of Standards & Technology (United States)

    2015-06-15

    Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014, a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic

  13. Calibration of the borated ion chamber at NIST reactor thermal column.

    Science.gov (United States)

    Wang, Z; Hertel, N E; Lennox, A

    2007-01-01

    In boron neutron capture therapy and boron neutron capture enhanced fast neutron therapy, the absorbed dose of tissue due to the boron neutron capture reaction is difficult to measure directly. This dose can be computed from the measured thermal neutron fluence rate and the (10)B concentration at the site of interest. A borated tissue-equivalent (TE) ion chamber can be used to directly measure the boron dose in a phantom under irradiation by a neutron beam. Fermilab has two Exradin 0.5 cm(3) Spokas thimble TE ion chambers, one loaded with boron, available for such measurements. At the Fermilab Neutron Therapy Facility, these ion chambers are generally used with air as the filling gas. Since alpha particles and lithium ions from the (10)B(n,alpha)(7)Li reactions have very short ranges in air, the Bragg-Gray principle may not be satisfied for the borated TE ion chamber. A calibration method is described in this paper for the determination of boron capture dose using paired ion chambers. The two TE ion chambers were calibrated in the thermal column of the National Institute of Standards and Technology (NIST) research reactor. The borated TE ion chamber is loaded with 1,000 ppm of natural boron (184 ppm of (10)B). The NIST thermal column has a cadmium ratio of greater than 400 as determined by gold activation. The thermal neutron fluence rate during the calibration was determined using a NIST fission chamber to an accuracy of 5.1%. The chambers were calibrated at two different thermal neutron fluence rates: 5.11 x 10(6) and 4.46 x 10(7)n cm(-2) s(-1). The non-borated ion chamber reading was used to subtract collected charge not due to boron neutron capture reactions. An optically thick lithium slab was used to attenuate the thermal neutrons from the neutron beam port so the responses of the chambers could be corrected for fast neutrons and gamma rays in the beam. The calibration factor of the borated ion chamber was determined to be 1.83 x 10(9) +/- 5.5% (+/- 1sigma) n

  14. 76 FR 22673 - Technology Innovation Program Advisory Board

    Science.gov (United States)

    2011-04-22

    ... National Institute of Standards and Technology Technology Innovation Program Advisory Board AGENCY... notice in the Federal Register announcing an open meeting for the Technology Innovation Program Advisory... rene.cesaro@nist.gov . SUPPLEMENTARY INFORMATION: The Technology Innovation Program (TIP)...

  15. Comment on "first accuracy evaluation of NIST-F2"

    CERN Document Server

    Gibble, Kurt

    2015-01-01

    We discuss the treatment of the systematic frequency shifts due to microwave lensing and distributed cavity phase in "First accuracy evaluation of NIST-F2" 2014 Metrologia 51 174-182. We explain that the microwave lensing frequency shift is generally non-zero and finite in the limit of no applied microwave field. This systematic error was incorrectly treated and we find that it contributes a significant frequency offset. Accounting for this shift implies that the measured microwave amplitude dependence (e.g due to microwave leakage) is comparable to the total reported inaccuracy. We also discuss the importance of vertically aligning the fountain perpendicular to the axis of the cavity feeds, when the cavity has only two independent feeds. Finally, we note that background gas collisions have a different behavior for cold clock atoms than for clock atoms at room-temperature, and therefore room temperature measurements do not directly apply to laser-cooled clocks.

  16. 75 FR 1595 - Establishment of NIST Smart Grid Advisory Committee and Solicitation of Nominations for Members

    Science.gov (United States)

    2010-01-12

    ... (Committee). The Committee will advise the Director of NIST in carrying out duties authorized by the Energy... the discretion of the Director of NIST. The Vice Chairperson shall perform the duties of the... Authority The Smart Grid Advisory Committee (Committee), is established to advise the Director of...

  17. Cold Neutron Research Facility begins operating at NIST

    Energy Technology Data Exchange (ETDEWEB)

    Zeman, E.J.

    1991-09-01

    Steady-state neutron beams are generally produced by fission in a nuclear reactor, whereas pulsed beams come from spallation neutron sources. Beams from a reactor have a distribution of wavelengths that is roughly Maxwellian, with a peak wavelength that depends on the temperature of the moderator that surrounds the fuel. Cold neutrons can be selected from the low-energy tail of the distribution, but the flux drops as 1/{lambda}{sup 4}. However, by shifting the whole spectrum to longer wavelengths one can dramatically increase the cold neutron flux. This is achieved by replacing part of the core moderator with a cold moderator, or cold source,' such as liquid deuterium (at about 30 K) or D{sub 2}O ice (at about 40 K). Neutrons lose energy to the moderator through collisions, producing a shifted spectrum from which one can select lower-energy neutrons with a roughly ten-fold improvement in the flux. Neutrons exhibit optical behavior such as refraction and total reflection. Thus one can use neutron guides - analogous to optical fibers - to conduct intense beams of neutrons from the reactor into a large experimental hall, dubbed a guide hall,' where background radiation is low. The Cold Neutron Research Facility was finally funded in 1987 and opened its doors this past June. CNRF is located at the 20-MW NIST research reactor, which began continuous operation in 1969. With some foresight, the designers of the original reactor allowed space for the addition of a cryogenic moderator, which is only now being exploited. NIST will develop 10 experimental stations for use by the research science community. Additional help in financing the facility comes from participating research teams made up of groups from industry, academe and government.

  18. Survey of Latest Wireless Cellular Technologies for Enhancement of Spectral Density at Reduced Cost

    CERN Document Server

    Jain, R K; Agrawal, N K

    2011-01-01

    The future of mobile wireless communication networks will include existing 3rd generation, 4th generation (implemented in Japan, USA, South Korea etc.), 5th generation (based on cognitive radio which implies the whole wireless world interconnection & WISDOM - Wireless innovative System for Dynamic Operating Megacommunications concept), 6th generation (with very high data rates Quality of Service (QoS) and service applications) and 7th generation (with space roaming). This paper is focused on the specifications of future generations and latest technologies to be used in future wireless mobile communication networks. However keeping in view the general poor masses of India, some of the future generation technologies will be embedded with 2G and 2.5G so that general masses may get the advantage of internet, multimedia services and the operators may get proper revenues with little extra expenditure in the existing mobile communication networks.

  19. Preparation and LSC Standardization of ''89Sr (DNP) Using the CIEMAT/NIST Method; Preparacion del ''89Sr(DNP) y calibracion por centelleo liquido, mediante el metodo CIEMAT/NIST

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Barquero, L.; Los Arcos Merino, J. M.; Grau Malonda, A.

    1994-07-01

    A procedure for preparation of liquid scintillation counting samples of the strontium DNP complex, labelled with ''89Sr, is described, the chemical quench, the counting stability and spectral evolution of this compound is studied in six scintillators, Toluene, Toluene-alcohol, Dioxane-naphthalene, HiSafe II, Ultima- Gold and Instagel. The liquid scintillation standardization of 89Sr-DNP by the CIEMAT/NIST method, using HiSafe II and Ultima-Gold scintillators, has been carried out. The discrepancies between experimental and computed efficiencies are lower than 0.38% and 0.48%, respectively. The solution has been standardized in terms of activity concentration to an overall uncertainty of 0,38%. (Author) 10 refs.

  20. Comparison of quartz standards for X-ray diffraction analysis: HSE A9950 (Sikron F600) and NIST SRM 1878.

    Science.gov (United States)

    Chisholm, Jim

    2005-06-01

    A further comparison of the Health and Safety Executive (HSE) standard quartz, A9950 (Sikron F600), and the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1878, standard respirable alpha-quartz, has been carried out for the four principal diffraction peaks. In the earlier comparison by Jeyaratnam and Nagar (1993, Ann Occup Hyg; 37: 167-79), the standards were both treated in ways which might change the particle size distribution and therefore the proportion of crystalline quartz. The two standards have now been compared in the most direct way possible with the minimum of sample treatment. There are no significant differences in the diffraction peak positions for the two standards. Nor do the peak area intensities differ significantly. The peak height intensities are consistently and significantly higher for Sikron F600 than for NIST SRM 1878. The particle size broadening of the diffraction peaks is evidently greater for NIST 1878, whose mass median diameter is quoted as 1.6 microm against 2.6 microm for Sikron F600. Taking the certified reference value for SRM 1878 as 95.5 +/- 1.1% crystalline quartz, the HSE standard A9950 (Sikron F600) contains 96.3 +/- 1.4% crystalline quartz based on a comparison of peak area intensities. On the same basis but using peak height intensities, the nominal crystalline quartz content of A9950 (Sikron F600) is 101.2 +/- 1.8%. Results obtained by comparison of quartz standards may not be generally applicable because of the effect of sample treatment on particle size and crystalline quartz content.

  1. Comment on "Frequency shifts in NIST Cs primary frequency standards due to transverse rf field gradients"

    CERN Document Server

    Gibble, Kurt

    2015-01-01

    We discuss the theoretical treatment of the microwave lensing frequency shift of the NIST-F1 and F2 atomic fountain clocks by Ashby et al. [Phy. Rev. A. 91, 033624 (2015)]. The shifts calculated by NIST are much smaller than the previously evaluated microwave lensing frequency shifts of other clocks contributing to International Atomic Time. We identify several fundamental problems in the NIST treatment and demonstrate that each significantly affects their results. We also show a smooth transition of microwave lensing frequency shifts to the photon recoil shift for large wave packets.

  2. Single point optical calibration of accelerometers at NIST

    Science.gov (United States)

    Payne, Bev

    2006-06-01

    Typical accelerometer calibrations by laser interferometer are performed by measuring displacement at three places on the shaker table. Each of these measurements, made along the perimeter of the accelerometer, requires repositioning and realigning of the interferometer. This is done to approximate the actual displacement of the accelerometer. Using a dual-coil shaker with a small moving element and two coaxially-located and rigidly-attached mounting tables allows placing the accelerometer on one table and measuring displacement directly on the center axis of the second table. This was found to work effectively at lower frequencies, up to about 5 kHz, with mounting tables of conventional materials such as stainless steel. However, for higher frequencies the use of steel results in unwanted relative motion between the two mounting tables. Mounting tables of beryllium with nickel coating have been used at NIST to overcome this difficulty. This paper shows the calibration results of single point, on-axis measurements, using fringe counting and sine-approximation methods. The results compare favorably with three point measurements made by fringe disappearance using a conventional piezo-electric shaker at frequencies up to 15 kHz.

  3. NIST Ionization Chamber “A” Sample-Height Corrections

    Science.gov (United States)

    Fitzgerald, Ryan

    2012-01-01

    For over 30 years scientists in the NIST radioactivity group have been using their pressurized ionization chamber “A” (PIC “A”) to make measurements of radioactivity and radioactive half-lives. We now have evidence that some of those reported measurements were incorrect due to slippage of the source positioning ring over time. The temporal change in the holder caused an error in the source-height within the chamber, which was thought to be invariant. This unaccounted-for height change caused a change in the detector response and thus a relative error in measured activity on the order of 10−5 to 10−3 per year, depending on the radionuclide. The drifting detector response affected calibration factors and half-life determinations. After discovering the problem, we carried out historic research and new sensitivity tests. As a result, we have created a quantitative model of the effect and have used that model to estimate corrections to some of the past measurement results from PIC “A”. In this paper we report the details and results of that model. Meanwhile, we have fixed the positioning ring and are recalibrating the detector using primary measurement methods and enhanced quality control measures. PMID:26900515

  4. NIST Ionization Chamber "A" Sample-Height Corrections.

    Science.gov (United States)

    Fitzgerald, Ryan

    2012-01-01

    For over 30 years scientists in the NIST radioactivity group have been using their pressurized ionization chamber "A" (PIC "A") to make measurements of radioactivity and radioactive half-lives. We now have evidence that some of those reported measurements were incorrect due to slippage of the source positioning ring over time. The temporal change in the holder caused an error in the source-height within the chamber, which was thought to be invariant. This unaccounted-for height change caused a change in the detector response and thus a relative error in measured activity on the order of 10(-5) to 10(-3) per year, depending on the radionuclide. The drifting detector response affected calibration factors and half-life determinations. After discovering the problem, we carried out historic research and new sensitivity tests. As a result, we have created a quantitative model of the effect and have used that model to estimate corrections to some of the past measurement results from PIC "A". In this paper we report the details and results of that model. Meanwhile, we have fixed the positioning ring and are recalibrating the detector using primary measurement methods and enhanced quality control measures.

  5. Review of an assortment of IR materials-devices technologies used for imaging in spectral bands ranging from the visible to very long wavelengths

    Science.gov (United States)

    DeWames, Roger E.

    2016-05-01

    In this paper we review the intrinsic and extrinsic technological properties of the incumbent technology, InP/In0.53Ga0.47As/InP, for imaging in the visible- short wavelength spectral band, InSb and HgCdTe for imaging in the mid-wavelength spectral band and HgCdTe for imaging in the long wavelength spectral band. These material systems are in use for a wide range of applications addressing compelling needs in night vision imaging, low light level astronomical applications and defense strategic satellite sensing. These materials systems are direct band gap energy semiconductors hence the internal quantum efficiency η, is near unity over a wide spectral band pass. A key system figure of merit of a shot noise limited detector technology is given by the equation (1+Jdark. /Jphoton), where Jdark is the dark current density and Jphoton ~qηΦ is the photocurrent density; Φ is the photon flux incident on the detector and q is the electronic charge. The capability to maintain this factor for a specific spectral band close to unity for low illumination conditions and low temperature onset of non-ideal dark current components, basically intrinsic diffusion limited performance all the way, is a marker of quality and versatility of a semiconductor detector technology. It also enables the highest temperature of operation for tactical illumination conditions. A purpose of the work reported in this paper is to explore the focal plane array data sets of photodiode detector technologies widely used to bench mark their fundamental and technology properties and identify paths for improvements.

  6. 75 FR 62369 - Technology Innovation Program Advisory Board

    Science.gov (United States)

    2010-10-08

    ... Innovation Program Advisory Board AGENCY: National Institute of Standards and Technology, Department of Commerce. ACTION: Notice of public meeting. SUMMARY: The Technology Innovation Program Advisory Board... address is rene.cesaro@nist.gov . SUPPLEMENTARY INFORMATION: The Technology Innovation Program...

  7. A summary of the Planck constant measurements using a watt balance with a superconducting solenoid at NIST

    CERN Document Server

    Schlamminger, S; Haddad, D; Newell, D B; Seifert, F; Chao, L S; Liu, R; Williams, E R; Pratt, J R

    2015-01-01

    Researchers at the National Institute of Standards and Technology have been using a watt balance, NIST-3, to measure the Planck constant $h$ for over ten years. Two recently published values disagree by more than one standard uncertainty. The motivation for the present manuscript is twofold. First, we correct the latest published number to take into account a recently discovered systematic error in mass dissemination at the Bureau International des Poids et Mesures (BIPM). Second, we provide guidance on how to combine the two numbers into one final result. In order to adequately reflect the discrepancy, we added an additional systematic uncertainty to the published uncertainty budgets. The final value of $h$ measured with NIST-3 is $h = 6.626\\,069\\,36(37)\\times 10^{-34}\\,\\mbox{J\\,s}$. This result is $77(57) \\times 10^{-9}$ fractionally higher than $h_{\\mathrm{90}}$. Each number in parentheses gives the value of the standard uncertainty in the last two digits of the respective value and $h_{\\mathrm{90}}$ is th...

  8. Nondestructive sensing technologies using micro-optical elements for applications in the NIR-MIR spectral regions

    Science.gov (United States)

    Otto, Thomas; Saupe, Ray; Bruch, Reinhard F.; Fritzsch, Uwe; Stock, Volker; Gessner, Thomas; Afanasyeva, Natalia I.

    2001-11-01

    The field of microtechnology is an important industrial and scientific resource for the 21st century. There is a great interest in spectroscopic sensors in the near and middle infrared (NIR-MIR) wavelength regions (1 - 2.5 micrometers ; 2.5 - 4.5 micrometers ; 4 - 6 micrometers ). The potential for cheap and small devices for nondestructive, remote sensing techniques at a molecular level has stimulated the design and development of more compact analyzer systems. Therefore we will try to build analyzers using micro optical components such as micromirrors and embossed micro gratings optimized for the above mentioned spectral ranges. Potentially, infrared sensors can be used for rapid nondestructive diagnostics of surfaces, liquids, gases, polymers and complex biological systems including proteins, blood, cells and cellular debris as well as body tissue. Furthermore, NIR-MIR microsensing spectroscopy will be utilized to monitor the chemical composition of petrochemical products like gasoline and diesel. In addition, miniature analyzers will be used for rapid measuring of food, in particular oil, starch and meat. In this paper we will present an overview of several new approaches for subsurface and surface sensing technologies based on the integration of optical micro devices, the most promising sensors for biomedical, environmental and industrial applications, data processing and evaluation algorithms for classification of the results. Both scientific and industrial applications will be discussed.

  9. A re-evaluation of the relativistic redshift on frequency standards at NIST, Boulder, Colorado, USA

    Science.gov (United States)

    Pavlis, Nikolaos K.; Weiss, Marc A.

    2017-08-01

    We re-evaluated the relativistic redshift correction applicable to the frequency standards at the National Institute of Standards and Technology (NIST) in Boulder, Colorado, USA, based on a precise GPS survey of three benchmarks on the roof of the building where these standards had been previously housed, and on global and regional geoid models supported by data from the GRACE and GOCE missions, including EGM2008, USGG2009, and USGG2012. We also evaluated the redshift offset based on the published NAVD88 geopotential number of the leveling benchmark Q407 located on the side of Building 1 at NIST, Boulder, Colorado, USA, after estimating the bias of the NAVD88 datum at our specific location. Based on these results, our current best estimate of the relativistic redshift correction, if frequency standards were located at the height of the leveling benchmark Q407 outside the second floor of Building 1, with respect to the EGM2008 geoid whose potential has been estimated to be {{W}0}=62 636 855.69 {{m}2} {{s}-2} , is equal to (-1798.50  ±  0.06)  ×  10-16. The corresponding value, with respect to an equipotential surface defined by the International Astronomical Union’s (IAU) adopted value of {{W}0}=62 636 856.0 {{m}2} {{s}-2} , is (-1798.53  ±  0.06)  ×  10-16. These values are comparable to the value of (-1798.70  ±  0.30)  ×  10-16, estimated by Pavlis and Weiss in 2003, with respect to an equipotential surface defined by {{W}0}=62 636 856.88 {{m}2} {{s}-2} . The minus sign implies that clocks run faster in the laboratory in Boulder than a corresponding clock located on the geoid. Contribution of US government, not subject to Copyright.

  10. NIST high throughput variable kinetic energy hard X-ray photoelectron spectroscopy facility

    Energy Technology Data Exchange (ETDEWEB)

    Weiland, C., E-mail: cweiland@bnl.gov [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Rumaiz, A.K. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973 (United States); Lysaght, P. [SEMATECH, 257 Fuller Road, Albany, NY 12203 (United States); Karlin, B.; Woicik, J.C.; Fischer, D. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

    2013-10-15

    Highlights: •High throughput HAPXES beamline provides beam energies between 2.1 and 6 keV. •Recent results in depth profiling of materials for next-generation CMOS. •Facility ideal or measurement of energy level alignment at buried interfaces. •Approved beamline NSLS II will provide wider energy range and X-ray flux. -- Abstract: We present an overview of the National Institute of Standards and Technology beamline X24A at the National Synchrotron Light Source at Brookhaven National Lab and recent work performed at the facility. The beamline is equipped for HAXPES measurements, with an energy range from 2.1 to 6 keV with Si(1 1 1) crystals. Recent measurements performed at the beamline include non-destructive depth dependent variable kinetic energy measurements of dielectric and semiconductor films and interfaces for microelectronics applications, band alignment at buried interfaces, and the electronic structure of bulk-like materials. The design and operation of the current beamline will be discussed, as well as the future NIST beamline at NSLS II.

  11. Analysis of LOCA Scenarios in the NIST Research Reactor Before and After Fuel Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Baek, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cheng, L. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Diamond, D. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-30

    An analysis has been done of hypothetical loss-of-coolant-accidents (LOCAs) in the research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The purpose of the analysis is to determine if the peak clad temperature remains below the Safety Limit, which is the blister temperature for the fuel. The configuration of the NBSR considered in the analysis is that projected for the future when changes will be made so that shutdown pumps do not operate when a LOCA signal is detected. The analysis was done for the present core with high-enriched uranium (HEU) fuel and with the proposed low-enriched uranium (LEU) fuel that would be used when the NBSR is converted from one to the other. The analysis consists of two parts. The first examines how the water would drain from the primary system following a break and the possibility for the loss of coolant from within the fuel element flow channels. This work is performed using the TRACE system thermal-hydraulic code. The second looks at the fuel clad temperature as a function of time given that the water may have drained from many of the flow channels and the water in the vessel is in a quasi-equilibrium state. The temperature behavior is investigated using the three-dimensional heat conduction code HEATING7.3. The results in all scenarios considered for both HEU and LEU fuel show that the peak clad temperature remains below the blister temperature.

  12. Bayesian regression models outperform partial least squares methods for predicting milk components and technological properties using infrared spectral data.

    Science.gov (United States)

    Ferragina, A; de los Campos, G; Vazquez, A I; Cecchinato, A; Bittante, G

    2015-11-01

    The aim of this study was to assess the performance of Bayesian models commonly used for genomic selection to predict "difficult-to-predict" dairy traits, such as milk fatty acid (FA) expressed as percentage of total fatty acids, and technological properties, such as fresh cheese yield and protein recovery, using Fourier-transform infrared (FTIR) spectral data. Our main hypothesis was that Bayesian models that can estimate shrinkage and perform variable selection may improve our ability to predict FA traits and technological traits above and beyond what can be achieved using the current calibration models (e.g., partial least squares, PLS). To this end, we assessed a series of Bayesian methods and compared their prediction performance with that of PLS. The comparison between models was done using the same sets of data (i.e., same samples, same variability, same spectral treatment) for each trait. Data consisted of 1,264 individual milk samples collected from Brown Swiss cows for which gas chromatographic FA composition, milk coagulation properties, and cheese-yield traits were available. For each sample, 2 spectra in the infrared region from 5,011 to 925 cm(-1) were available and averaged before data analysis. Three Bayesian models: Bayesian ridge regression (Bayes RR), Bayes A, and Bayes B, and 2 reference models: PLS and modified PLS (MPLS) procedures, were used to calibrate equations for each of the traits. The Bayesian models used were implemented in the R package BGLR (http://cran.r-project.org/web/packages/BGLR/index.html), whereas the PLS and MPLS were those implemented in the WinISI II software (Infrasoft International LLC, State College, PA). Prediction accuracy was estimated for each trait and model using 25 replicates of a training-testing validation procedure. Compared with PLS, which is currently the most widely used calibration method, MPLS and the 3 Bayesian methods showed significantly greater prediction accuracy. Accuracy increased in moving from

  13. [The Identification of the Origin of Chinese Wolfberry Based on Infrared Spectral Technology and the Artificial Neural Network].

    Science.gov (United States)

    Li, Zhong; Liu, Ming-de; Ji, Shou-xiang

    2016-03-01

    The Fourier Transform Infrared Spectroscopy (FTIR) is established to find the geographic origins of Chinese wolfberry quickly. In the paper, the 45 samples of Chinese wolfberry from different places of Qinghai Province are to be surveyed by FTIR. The original data matrix of FTIR is pretreated with common preprocessing and wavelet transform. Compared with common windows shifting smoothing preprocessing, standard normal variation correction and multiplicative scatter correction, wavelet transform is an effective spectrum data preprocessing method. Before establishing model through the artificial neural networks, the spectra variables are compressed by means of the wavelet transformation so as to enhance the training speed of the artificial neural networks, and at the same time the related parameters of the artificial neural networks model are also discussed in detail. The survey shows even if the infrared spectroscopy data is compressed to 1/8 of its original data, the spectral information and analytical accuracy are not deteriorated. The compressed spectra variables are used for modeling parameters of the backpropagation artificial neural network (BP-ANN) model and the geographic origins of Chinese wolfberry are used for parameters of export. Three layers of neural network model are built to predict the 10 unknown samples by using the MATLAB neural network toolbox design error back propagation network. The number of hidden layer neurons is 5, and the number of output layer neuron is 1. The transfer function of hidden layer is tansig, while the transfer function of output layer is purelin. Network training function is trainl and the learning function of weights and thresholds is learngdm. net. trainParam. epochs=1 000, while net. trainParam. goal = 0.001. The recognition rate of 100% is to be achieved. It can be concluded that the method is quite suitable for the quick discrimination of producing areas of Chinese wolfberry. The infrared spectral analysis technology

  14. Center for Nanoscale Science and Technology

    Science.gov (United States)

    NIST Center for Nanoscale Science and Technology (Program website, free access)   Currently there is no database matching your keyword search, but the NIST Center for Nanoscale Science and Technology website may be of interest. The Center for Nanoscale Science and Technology enables science and industry by providing essential measurement methods, instrumentation, and standards to support all phases of nanotechnology development, from discovery to production.

  15. Water heat pipe blackbody as a reference spectral radiance source between 50°C and 250°C

    Science.gov (United States)

    Noorma, M.; Mekhontsev, S.; Khromchenko, V.; Litorja, M.; Cagran, C.; Zeng, J.; Hanssen, L.

    2006-04-01

    Realization of a radiometric temperature scale for near ambient temperatures with accuracy at the 20 to 50 mK level is crucial for a number of demanding military and commercial applications. In support of such measurements, radiation sources with high stability and spatial uniformity must be developed as reference and working standards. Traditionally, the temperature scale, maintained at the National Institute of Standards and Technology (NIST), relies on water bath and oil bath blackbodies in this temperature range. Recently, a water heat pipe blackbody was used at NIST as a spectral radiance source in a spectral emissivity measurement facility. Now a new, more versatile high emissivity water heat pipe blackbody was designed and characterized to be used as a reference radiance source for the radiometric temperature scale realization between 50 °C and 250 °C. Furthermore, it will serve as a reference source for the infrared spectral radiance measurements between 2.5 μm and 20 μm. The calculated spectral emissivity of the painted copper alloy cavity was verified by reflectance measurements using a CO II laser at 10.6 μm wavelength. The spatial thermal uniformity and stability of the blackbody were characterized. Two independent realizations of the radiometric temperature scale were compared in order to verify the accuracy of the scale. Radiance temperature, calculated from the cavity temperature measured with a calibrated PRT contact thermometer and from the emissivity of the cavity, was compared to the radiance temperature, directly measured with a reference pyrometer, which was calibrated with a set of fixed point blackbodies. The difference was found to be within measurement uncertainties.

  16. Measurement of the Surface and Underground Neutron Spectra with the UMD/NIST Fast Neutron Spectrometers

    Science.gov (United States)

    Langford, Thomas J.

    The typical fast neutron detector falls into one of two categories, Bonner sphere spectrometers and liquid scintillator proton recoil detectors. These two detector types have traditionally been used to measure fast neutrons at the surface and in low background environments. The cosmogenic neutron spectrum and flux is an important parameter for a number of experimental efforts, including procurement of low background materials and the prediction of electronic device faults. Fast neutrons can also cause problems for underground low-background experiments, through material activation or signals that mimic rare events. Current detector technology is not sufficient to properly characterize these backgrounds. To this end, the University of Maryland and the National Institute of Standards and Technology designed, developed, and deployed two Fast Neutron Spectrometers (FaNS) comprised of plastic scintillator and 3He proportional counters. The detectors are based upon capture-gated spectroscopy, a technique that demands a delayed coincidence between a neutron scatter and the resulting neutron capture after thermalization. This technique provides both particle identification and knowledge that the detected neutron fully thermalized. This improves background rejection capabilities and energy resolution. Presented are the design, development, and deployment of FaNS-1 and FaNS-2. Both detectors were characterized using standard fields at NIST, including calibrated 252Cf neutron sources and two monoenergetic neutron generators. Measurements of the surface fast neutron spectrum and flux have been made with both detectors, which are compared with previous measurements by traditional detectors. Additionally, FaNS-1 was deployed at the Kimballton Underground Research Facility (KURF) in Ripplemead, VA. A measurement of the fast neutron spectrum and flux at KURF is presented as well. FaNS-2 is currently installed in a shallow underground laboratory where it is measuring the muon

  17. A Comparison of 1 T(Omega) and 10 T (Omega) High Resistance Standards Between NIST and Sandia

    Energy Technology Data Exchange (ETDEWEB)

    Jarrett, D.G.; Dziuba, R.F.; Kraft, M.E.

    1999-04-23

    NIST-built 10 T{Omega} and commercial 1 T{Omega} standard resistors were hand carried between NIST and Sandia for a high resistance comparison. The comparison tested the ruggedness of the new NIST-built standard resistors, provided a check of the scaling between the two laboratories, supported measurements to reestablish NIST calibration services at 10 T{Omega} and 100 T{Omega}, and demonstrated the possibility of establishing a NIST high resistance measurement assurance program (MAP). The comparison has demonstrated agreement on the order of 0.07% which is within the expanded uncertainties (coverage factor = 2) of NIST and Sandia at 1 T{Omega} and 10 T{Omega}.

  18. Advanced Manufacturing Technologies (AMT): Manufacturing Initiative Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA supports the Advanced Manufacturing National Program Office (AMNPO). Hosted by the National Institute of Standards and Technology (NIST) the AMNPO is...

  19. Tailoring NIST Security Controls for the Ground System: Selection and Implementation -- Recommendations for Information System Owners

    Science.gov (United States)

    Takamura, Eduardo; Mangum, Kevin

    2016-01-01

    . Certain protective measures for the general enterprise may not be as efficient within the ground segment. This is what the authors have concluded through observations and analysis of patterns identified from the various security assessments performed on NASA missions such as MAVEN, OSIRIS-REx, New Horizons and TESS, to name a few. The security audits confirmed that the framework for managing information system security developed by the National Institute of Standards and Technology (NIST) for the federal government, and adopted by NASA, is indeed effective. However, the selection of the technical, operational and management security controls offered by the NIST model - and how they are implemented - does not always fit the nature and the environment where the ground system operates in even though there is no apparent impact on mission success. The authors observed that unfit controls, that is, controls that are not necessarily applicable or sufficiently effective in protecting the mission systems, are often selected to facilitate compliance with security requirements and organizational expectations even if the selected controls offer minimum or non-existent protection. This paper identifies some of the standard security controls that can in fact protect the ground system, and which of them offer little or no benefit at all. It offers multiple scenarios from real security audits in which the controls are not effective without, of course, disclosing any sensitive information about the missions assessed. In addition to selection and implementation of controls, the paper also discusses potential impact of recent legislation such as the Federal Information Security Modernization Act (FISMA) of 2014 - aimed at the enterprise - on the ground system, and offers other recommendations to Information System Owners (ISOs).

  20. Retrospective Analysis of NIST Standard Reference Material 1450, Fibrous Glass Board, for Thermal Insulation Measurements.

    Science.gov (United States)

    Zarr, Robert R; Heckert, N Alan; Leigh, Stefan D

    2014-01-01

    Thermal conductivity data acquired previously for the establishment of Standard Reference Material (SRM) 1450, Fibrous Glass Board, as well as subsequent renewals 1450a, 1450b, 1450c, and 1450d, are re-analyzed collectively and as individual data sets. Additional data sets for proto-1450 material lots are also included in the analysis. The data cover 36 years of activity by the National Institute of Standards and Technology (NIST) in developing and providing thermal insulation SRMs, specifically high-density molded fibrous-glass board, to the public. Collectively, the data sets cover two nominal thicknesses of 13 mm and 25 mm, bulk densities from 60 kg·m(-3) to 180 kg·m(-3), and mean temperatures from 100 K to 340 K. The analysis repetitively fits six models to the individual data sets. The most general form of the nested set of multilinear models used is given in the following equation: [Formula: see text]where λ(ρ,T) is the predicted thermal conductivity (W·m(-1)·K(-1)), ρ is the bulk density (kg·m(-3)), T is the mean temperature (K) and ai (for i = 1, 2, … 6) are the regression coefficients. The least squares fit results for each model across all data sets are analyzed using both graphical and analytic techniques. The prevailing generic model for the majority of data sets is the bilinear model in ρ and T. [Formula: see text] One data set supports the inclusion of a cubic temperature term and two data sets with low-temperature data support the inclusion of an exponential term in T to improve the model predictions. Physical interpretations of the model function terms are described. Recommendations for future renewals of SRM 1450 are provided. An Addendum provides historical background on the origin of this SRM and the influence of the SRM on external measurement programs.

  1. Accident Analysis for the NIST Research Reactor Before and After Fuel Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Baek J.; Diamond D.; Cuadra, A.; Hanson, A.L.; Cheng, L-Y.; Brown, N.R.

    2012-09-30

    Postulated accidents have been analyzed for the 20 MW D2O-moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analysis has been carried out for the present core, which contains high enriched uranium (HEU) fuel and for a proposed equilibrium core with low enriched uranium (LEU) fuel. The analyses employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron transport calculations were performed with the MCNPX code to determine homogenized fuel compositions in the lower and upper halves of each fuel element and to determine the resulting neutronic properties of the core. The accident analysis employed a model of the primary loop with the RELAP5 code. The model includes the primary pumps, shutdown pumps outlet valves, heat exchanger, fuel elements, and flow channels for both the six inner and twenty-four outer fuel elements. Evaluations were performed for the following accidents: (1) control rod withdrawal startup accident, (2) maximum reactivity insertion accident, (3) loss-of-flow accident resulting from loss of electrical power with an assumption of failure of shutdown cooling pumps, (4) loss-of-flow accident resulting from a primary pump seizure, and (5) loss-of-flow accident resulting from inadvertent throttling of a flow control valve. In addition, natural circulation cooling at low power operation was analyzed. The analysis shows that the conversion will not lead to significant changes in the safety analysis and the calculated minimum critical heat flux ratio and maximum clad temperature assure that there is adequate margin to fuel failure.

  2. A wide spectral range single-photon avalanche diode fabricated in an advanced 180 nm CMOS technology

    NARCIS (Netherlands)

    Mandai, S.; Fishburn, M.W.; Maruyama, Y.; Charbon, E.

    2012-01-01

    We present a single-photon avalanche diode (SPAD) with a wide spectral range fabricated in an advanced 180 nm CMOS process. The realized SPAD achieves 20 % photon detection probability (PDP) for wavelengths ranging from 440 nm to 820 nm at an excess bias of 4V, with 30 % PDP at wavelengths from 520

  3. A wide spectral range single-photon avalanche diode fabricated in an advanced 180 nm CMOS technology

    NARCIS (Netherlands)

    Mandai, S.; Fishburn, M.W.; Maruyama, Y.; Charbon, E.

    2012-01-01

    We present a single-photon avalanche diode (SPAD) with a wide spectral range fabricated in an advanced 180 nm CMOS process. The realized SPAD achieves 20 % photon detection probability (PDP) for wavelengths ranging from 440 nm to 820 nm at an excess bias of 4V, with 30 % PDP at wavelengths from 520

  4. Investigation of Spectral Response Measurement Technology for Silicon Solar Cells%硅太阳电池光谱响应测试技术研究

    Institute of Scientific and Technical Information of China (English)

    罗玉峰; 杨祚宝; 廖卫兵; 张发云; 刘波; 李玲

    2012-01-01

    对太阳电池光谱响应理论及测试技术的进行了研究,通过绝对光谱响应与量子效率的依赖关系,由绝对光谱响应测数据推导出了太阳电池的外量子效率.采用LabVIEW虚拟仪器技术,系统地将计算机与单色仪、锁相放大器等仪器硬件结合起来,设计了一套集成化及自动化程度较高的太阳电池光谱响应测量系统.系统扫描光谱范围为400~1 200 nm,步进波长最小可达1 nm,可满足硅太阳电池光谱响应测试的需要.该测试系统对硅太阳电池光谱响应及偏置光源下的量子效率进行多次测试,结果表明:测量系统稳定性高,重复性能较好.%The principle of Spectral response and the measurement technology for solar cells were investigated. Base on quantum efficiency dependence on absolute spectral response, external quantum efficiency was deduced by the measuring data of the absolute spectral response. A highly automatic spectral response measurement system was developed for silicon solar cells using virtual instrument technology base on Lab VIEW which integrated software of computer with monochrometer, lock-in amplifier and other instrument hardware systematically. The range of the scanning wavelength was 400 nm to 1 200 nm and the minimum step wavelength was 1 nm which could meet the requirement of spectral response measurement for silicon solar cells. Several measurement results showed that the measurement system has highly repeatability and accuracy through measuring the spectral response and quantum efficiency under the bias light of silicon solar cells with this measurement system.

  5. DELAMINATION AND XRF ANALYSIS OF NIST LEAD IN PAINT FILM STANDARDS

    Science.gov (United States)

    The objectives of this protocol were to remove the laminate coating from lead paint film standards acquired from NIST by means of surface heating. The average XRF value did not change after removal of the polymer coating suggesting that this protocol is satisfactory for renderin...

  6. Eulerian–Lagrangian RANS Model Simulations of the NIST Turbulent Methanol Spray Flame

    NARCIS (Netherlands)

    Zhu, Shanglong; Roekaerts, Dirk; Pozarlik, Artur; Meer, van der Theo

    2015-01-01

    A methanol spray flame in a combustion chamber of the NIST was simulated using an Eulerian–Lagrangian RANS model. Experimental data and previous numerical investigations by other researchers on this flame were analyzed to develop methods for more comprehensive model validation. The inlet boundary co

  7. NIST ThermoData Engine: Extension to Solvent Design and Propagation of Uncertainties for Process Simulation

    DEFF Research Database (Denmark)

    Diky, Vladimir; Chirico, Robert D.; Muzny, Chris;

    ThermoData Engine (TDE, NIST Standard Reference Databases 103a and 103b) is the first product that implements the concept of Dynamic Data Evaluation in the fields of thermophysics and thermochemistry, which includes maintaining the comprehensive and up-to-date database of experimentally measured...

  8. Performance of the NIST goniocolorimeter with a broad-band source and multichannel charged coupled device based spectrometer

    Science.gov (United States)

    Podobedov, V. B.; Miller, C. C.; Nadal, M. E.

    2012-09-01

    The authors describe the NIST high-efficiency instrument for measurements of bidirectional reflectance distribution function of colored materials, including gonioapparent materials such as metallic and pearlescent coatings. The five-axis goniospectrometer measures the spectral reflectance of samples over a wide range of illumination and viewing angles. The implementation of a broad-band source and a multichannel CCD spectrometer corrected for stray light significantly increased the efficiency of the goniometer. In the extended range of 380 nm to 1050 nm, a reduction of measurement time from a few hours to a few minutes was obtained. Shorter measurement time reduces the load on the precise mechanical assembly ensuring high angular accuracy over time. We describe the application of matrix-based correction of stray light and the extension of effective dynamic range of measured fluxes to the values of 106 to 107 needed for the absolute characterization of samples. The measurement uncertainty was determined to be 0.7% (k = 2), which is comparable with similar instruments operating in a single channel configuration. Several examples of reflectance data obtained with the improved instrument indicate a 0.3% agreement compared to data collected with the single channel configuration.

  9. Wavelength conversion based spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin

    There has been a strong, application driven development of Si-based cameras and spectrometers for imaging and spectral analysis of light in the visible and near infrared spectral range. This has resulted in very efficient devices, with high quantum efficiency, good signal to noise ratio and high...... resolution for this spectral region. Today, an increasing number of applications exists outside the spectral region covered by Si-based devices, e.g. within cleantech, medical or food imaging. We present a technology based on wavelength conversion which will extend the spectral coverage of state of the art...... visible or near infrared cameras and spectrometers to include other spectral regions of interest....

  10. [Analysis of software for identifying spectral line of laser-induced breakdown spectroscopy based on LabVIEW].

    Science.gov (United States)

    Hu, Zhi-yu; Zhang, Lei; Ma, Wei-guang; Yan, Xiao-juan; Li, Zhi-xin; Zhang, Yong-zhi; Wang, Le; Dong, Lei; Yin, Wang-bao; Jia, Suo-tang

    2012-03-01

    Self-designed identifying software for LIBS spectral line was introduced. Being integrated with LabVIEW, the soft ware can smooth spectral lines and pick peaks. The second difference and threshold methods were employed. Characteristic spectrum of several elements matches the NIST database, and realizes automatic spectral line identification and qualitative analysis of the basic composition of sample. This software can analyze spectrum handily and rapidly. It will be a useful tool for LIBS.

  11. Neutron Transport Simulations for NIST Neutron Lifetime Experiment

    Science.gov (United States)

    Li, Fangchen; BL2 Collaboration Collaboration

    2016-09-01

    Neutrons in stable nuclei can exist forever; a free neutron lasts for about 15 minutes on average before it beta decays to a proton, an electron, and an antineutrino. Precision measurements of the neutron lifetime test the validity of weak interaction theory and provide input into the theory of the evolution of light elements in the early universe. There are two predominant ways of measuring the neutron lifetime: the bottle method and the beam method. The bottle method measures decays of ultracold neutrons that are stored in a bottle. The beam method measures decay protons in a beam of cold neutrons of known flux. An improved beam experiment is being prepared at the National Institute of Science and Technology (Gaithersburg, MD) with the goal of reducing statistical and systematic uncertainties to the level of 1 s. The purpose of my studies was to develop computer simulations of neutron transport to determine the beam collimation and study the neutron distribution's effect on systematic effects for the experiment, such as the solid angle of the neutron flux monitor. The motivation for the experiment and the results of this work will be presented. This work was supported, in part, by a Grant to Gettysburg College from the Howard Hughes Medical Institute through the Precollege and Undergraduate Science Education Program.

  12. An Atomic Abacus: Trapped ion quantum computing experiments at NIST

    Science.gov (United States)

    Demarco, Brian

    2003-03-01

    Trapped atomic ions are an ideal system for exploring quantum information science because deterministic state preparation and efficient state detection are possible and coherent manipulation of atomic systems is relatively advanced. In our experiment, a few singly charged Be ions are confined by static and radio-frequency electric fields in a micro-machined linear Paul trap. The internal and motional states of the ions are coherently manipulated using applied laser light. Our current work focuses on demonstrating the necessary ingredients to produce a scalable quantum computing scheme and on simplifying and improving quantum logic gates. I will speak about a new set of experiments that was made possible by recent improvements in trap technology. A novel trap with multiple trapping regions was used to demonstrate the first steps towards a fully scalable quantum computing scheme. Single ions were ``shuttled" between trapping regions without disturbing the ion's motional and internal state, and two ions were separated from a single to two different trapping zones. Improvements in the trap manufacturing process has led to a reduction of nearly two orders of magnitude in the ion's motional heating rate, making possible two new improved logic gates. The first gate utilizes the wave-packet nature of the ions to tune the laser-atom interaction and achieve a controlled-NOT gate between a single ion's spin and motional states. The second, a two-ion phase gate, uses phase-space dynamics to produce a state-sensitive geometric phase. I will end with a quick look at experiments using a Mg ion to sympathetically cool a simultaneously trapped Be ion and a glimpse of the next generation of ions traps currently under construction.

  13. Femtosecond Laser Ablation Multicollector ICPMS Analysis of Uranium Isotopes in NIST Glass

    Energy Technology Data Exchange (ETDEWEB)

    Duffin, Andrew M.; Springer, Kellen WE; Ward, Jesse D.; Jarman, Kenneth D.; Robinson, John W.; Endres, Mackenzie C.; Hart, Garret L.; Gonzalez, Jhanis J.; Oropeza, Dayana; Russo, Richard; Willingham, David G.; Naes, Benjamin E.; Fahey, Albert J.; Eiden, Gregory C.

    2015-02-06

    We have utilized femtosecond laser ablation coupled to multi-collector inductively couple plasma mass spectrometry to measure the uranium isotopic content of NIST 61x (x=0,2,4,6) glasses. The uranium content of these glasses is a linear two-component mixing between isotopically natural uranium and the isotopically depleted spike used in preparing the glasses. Laser ablation results match extremely well, generally within a few ppm, with solution analysis following sample dissolution and chemical separation. In addition to isotopic data, sample utilization efficiency measurements indicate that over 1% of ablated uranium atoms reach a mass spectrometer detector, making this technique extremely efficient. Laser sampling also allows for spatial analysis and our data indicate that rare uranium concentration inhomogeneities exist in NIST 616 glass.

  14. [Review of digital ground object spectral library].

    Science.gov (United States)

    Zhou, Xiao-Hu; Zhou, Ding-Wu

    2009-06-01

    A higher spectral resolution is the main direction of developing remote sensing technology, and it is quite important to set up the digital ground object reflectance spectral database library, one of fundamental research fields in remote sensing application. Remote sensing application has been increasingly relying on ground object spectral characteristics, and quantitative analysis has been developed to a new stage. The present article summarized and systematically introduced the research status quo and development trend of digital ground object reflectance spectral libraries at home and in the world in recent years. Introducing the spectral libraries has been established, including desertification spectral database library, plants spectral database library, geological spectral database library, soil spectral database library, minerals spectral database library, cloud spectral database library, snow spectral database library, the atmosphere spectral database library, rocks spectral database library, water spectral database library, meteorites spectral database library, moon rock spectral database library, and man-made materials spectral database library, mixture spectral database library, volatile compounds spectral database library, and liquids spectral database library. In the process of establishing spectral database libraries, there have been some problems, such as the lack of uniform national spectral database standard and uniform standards for the ground object features as well as the comparability between different databases. In addition, data sharing mechanism can not be carried out, etc. This article also put forward some suggestions on those problems.

  15. Validation of spectral radiance assignments to integrating sphere radiance standards for the Advanced Baseline Imager

    Science.gov (United States)

    Johnson, B. C.; Maxwell, Stephen; Shirley, Eric; Slack, Kim; Graham, Gary D.

    2014-09-01

    The Advanced Baseline Imager (ABI) is the next-generation imaging sensor for the National Oceanic and Atmospheric Administration's (NOAA's) operational meteorological satellites in geostationary orbit. One pathway for traceability to reference standards of the visible and near-infrared radiometric response for ABI is to a 1.65 m diameter integrating sphere source standard of spectral radiance. This source illuminates the full entrance pupil via the ABI Earth-view port, thus determining the absolute spectral radiance responsivity in the visible and shortwave infrared. The spectral radiance values of the large sphere are assigned by Exelis using a double monochromator and a 15.24 cm diameter integrating sphere source standard that is calibrated by NIST. As part of the ABI program, Exelis was required by NASA to have the spectral radiance values assigned by Exelis to the large sphere be validated by NIST. Here we report the results of that activity, which took place in April, 2013. During the week of April 8, Exelis calibrated the 1.65 m diameter sphere at all 24 levels that correspond to the ABI calibration protocol. During the week of April 15, the NIST validation exercise for five selected levels took place. NIST deployed a portable spectral radiance source, a filter radiometer restricted to the visible and near-infrared, and two spectroradiometers that covered from 350 nm to 2500 nm. The NIST sphere source served as the validation standard. The comparison results, which are reported at the ABI bands, agreed to within the combined uncertainties. We describe the methodology, results, and uncertainty estimates related to this effort.

  16. Final results of bilateral comparison between NIST and PTB for flows of high pressure natural gas

    Science.gov (United States)

    Mickan, B.; Toebben, H.; Johnson, A.; Kegel, T.

    2013-01-01

    In 2009 NIST developed a US national flow standard to provide traceability for flow meters used for custody transfer of pipeline quality natural gas. NIST disseminates the SI unit of flow by calibrating a customer flow meter against a parallel array of turbine meter working standards, which in turn are traceable to a pressure-volume-temperature-time (PVTt) primary standard. The calibration flow range extends from 0.125 actual m3/s to 9 actual m3/s with an expanded uncertainty as low as 0.22% at high flows, and increasing to almost 0.40% at the lowest flows. Details regarding the traceability chain and uncertainty analysis are documented in prior publications. The current manuscript verifies NIST's calibration uncertainty via a bilateral comparison with the German National Metrology Institute PTB. The results of the bilateral are linked to the 2006 key comparison results between three EURAMET national metrology institutes (i.e., PTB, VSL and LNE). Linkage is accomplished in spite of using a different transfer standard in the bilateral versus the key comparison. A mathematical proof is included that demonstrates that the relative difference between a laboratory's measured flow and the key comparison reference value is independent of the transfer package for most flow measurement applications. The bilateral results demonstrate that NIST's natural gas flow measurements are within their specified uncertainties and are equivalent to those of the EURAMET National Metrology Institutes. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  17. JCPDS-ICDD Research Associateship (Cooperative Program with NBS/NIST)

    OpenAIRE

    Wong-Ng, W.; McMurdie, H. F.; Hubbard, C. R.; Mighell, A. D.

    2001-01-01

    The Research Associateship program of the Joint Committee on Powder Diffraction-International Centre for Diffraction Data (JCPDS-ICDD, now known as the ICDD) at NBS/NIST was a long standing (over 35 years) successful industry-government cooperation. The main mission of the Associateship was to publish high quality x-ray reference patterns to be included in the Powder Diffraction File (PDF). The PDF is a continuing compilation of patterns gathered from many sources, compiled and published by t...

  18. Towards Improving the NIST Fingerprint Image Quality (NFIQ) Algorithm (Extended Version)

    CERN Document Server

    Merkle, Johannes; Bausinger, Oliver; Breitenstein, Marco; Elwart, Kristina; Nuppeney, Markus

    2010-01-01

    The NIST Fingerprint Image Quality (NFIQ) algorithm has become a standard method to assess fingerprint image quality. However, in many applications a more accurate and reliable assessment is desirable. In this publication, we report on our efforts to optimize the NFIQ algorithm by a re-training of the underlying neural network based on a large fingerprint image database. Although we only achieved a marginal improvement, our work has revealed several areas for potential optimization.

  19. Study on the mechanism of human blood glucose concentration measuring using mid-infrared spectral analysis technology

    Science.gov (United States)

    Li, Xiang

    2016-10-01

    All forms of diabetes increase the risk of long-term complications. Blood glucose monitoring is of great importance for controlling diabetes procedure, preventing the complications and improving the patient's life quality. At present, the clinical blood glucose concentration measurement is invasive and could be replaced by noninvasive spectroscopy analytical techniques. The mid-infrared spectral region contains strong characteristic and well-defined absorption bands. Therefore, mid-infrared provides an opportunity for monitoring blood glucose invasively with only a few discrete bonds. Although the blood glucose concentration measurement using mid-infrared spectroscopy has a lot of advantages, the disadvantage is also obvious. The absorption in this infrared region is fundamental molecular group vibration. Absorption intensity is very strong, especially for biological molecules. In this paper, it figures out that the osmosis rate of glucose has a certain relationship with the blood glucose concentration. Therefore, blood glucose concentration could be measured indirectly by measuring the glucose exudate in epidermis layer. Human oral glucose tolerance tests were carried out to verify the correlation of glucose exudation in shallow layer of epidermis layer and blood glucose concentration. As it has been explained above, the mid-infrared spectral region contains well-defined absorption bands, the intensity of absorption peak around 1123 cm-1 was selected to measure the glucose and that around 1170 cm-1 was selected as reference. Ratio of absorption peak intensity was recorded for each set of measurement. The effect and importance of the cleaning the finger to be measured before spectrum measuring are discussed and also verified by experiment.

  20. NIST Accelerator Facilities And Programs In Support Of Industrial Radiation Research

    Science.gov (United States)

    Bateman, F. B.; Desrosiers, M. F.; Hudson, L. T.; Coursey, B. M.; Bergstrom, P. M.; Seltzer, S. M.

    2003-08-01

    NIST's Ionizing Radiation Division maintains and operates three electron accelerators used in a number of applications including waste treatment and sterilization, radiation hardness testing, detector calibrations and materials modification studies. These facilities serve a large number of governmental, academic and industrial users as well as an active intramural research program. They include a 500 kV cascaded-rectifier accelerator, a 2.5 MV electron Van de Graaff accelerator and a 7 to 32 MeV electron linac, supplying beams ranging in energy from a few keV up to 32 MeV. In response to the recent anthrax incident, NIST along with the US Postal Service and the Armed Forces Radiobiology Research Institute (AFRRI) are working to develop protocols and testing procedures for the USPS mail sanitization program. NIST facilities and personnel are being employed in a series of quality-assurance measurements for both electron- and photon-beam sanitization. These include computational modeling, dose verification and VOC (volatile organic compounds) testing using megavoltage electron and photon sources.

  1. Improving Spectral Capacity and Wireless Network Coverage by Cognitive Radio Technology and Relay Nodes in Cellular Systems

    DEFF Research Database (Denmark)

    Frederiksen, Flemming Bjerge

    2008-01-01

    Methods to enhance the use of the frequency spectrum by automatical spectrum sensing plus spectrum sharing in a cognitive radio technology context have been presented and discussed in this paper. Ideas to improve the wireless transmission by orthogonal OFDM-based communication and to increase...

  2. Research of beam conditioning technologies using continuous phase plate, Multi-FM smoothing by spectral dispersion and polarization smoothing

    Science.gov (United States)

    Zhang, Rui; Jia, Huaiting; Tian, Xiaocheng; Yuan, Haoyu; Zhu, Na; Su, Jingqin; Hu, Dongxia; Zhu, Qihua; Zheng, Wanguo

    2016-10-01

    In the research of inertial confinement fusion, laser plasma interaction (LPI) is becoming a key problem that affects ignition. Here, multi-frequency modulation (Multi-FM) smoothing by spectral dispersion (SSD), continuous phase plate (CPP) and polarization smoothing (PS) were experimentally studied and implemented on the SG-III laser facility. After using these techniques, the far field distribution of SG-Ⅲ laser facility can be adjusted, controlled and repeated accurately. The output spectrums of the cascade phase modulators used for Multi-FM SSD were stable and the FM-to-AM effect can be restrained. Experiments on SG-III laser facility indicate that when the number of color cycles adopts 1, imposing SSD with 3.3 times diffraction limit (TDL) did not lead to pinhole closure in the spatial filters of preamplifier and main amplifiers with 30-TDL pinhole size. The nonuniformity of the focal spots using Multi-FM SSD, CPP and PS drops to 0.18, comparing to 0.26 with CPP+SSD, 0.57 with CPP+PS and 0.84 with only CPP and wedged lens. Polarization smoothing using flat birefringent plate in the convergent beam of final optics assembly (FOA) was studied. The PS plates were manufactured and equipped on SG-III laser facility for LPI research. Combined beam smoothing and polarization manipulation were also studied to solve the LPI problem. Results indicate that through adjusting dispersion directions of SSD beams in a quad, two dimensional SSD can be obtained. Using polarization control plate (PCP), polarization on the near field and far field can be manipulated, providing new method to solve LPI problem in indirect drive laser fusion.

  3. Spectral Methods

    CERN Document Server

    Shen, Jie; Wang, Li-Lian

    2011-01-01

    Along with finite differences and finite elements, spectral methods are one of the three main methodologies for solving partial differential equations on computers. This book provides a detailed presentation of basic spectral algorithms, as well as a systematical presentation of basic convergence theory and error analysis for spectral methods. Readers of this book will be exposed to a unified framework for designing and analyzing spectral algorithms for a variety of problems, including in particular high-order differential equations and problems in unbounded domains. The book contains a large

  4. Design and fabrication process of silicon micro-calorimeters on simple SOI technology for X-ray spectral imaging

    Energy Technology Data Exchange (ETDEWEB)

    Aliane, A. [CEA/LETI, MINATEC, 17, Avenue des Martyrs, 38054 Grenoble (France)], E-mail: abdelkader.aliane@cea.fr; Agnese, P. [CEA/LETI, MINATEC, 17, Avenue des Martyrs, 38054 Grenoble (France); Pigot, C.; Sauvageot, J.-L. [Laboratoire AIM, CNRS, Universite Paris Diderot, CEA/DSM/IRFU/Service d' Astrophysique, Bat. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Moro, F. de; Ribot, H.; Gasse, A. [CEA/LETI, MINATEC, 17, Avenue des Martyrs, 38054 Grenoble (France); Szeflinski, V. [Laboratoire AIM, CNRS, Universite Paris Diderot, CEA/DSM/IRFU/Service d' Astrophysique, Bat. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Gobil, Y. [CEA/LETI, MINATEC, 17, Avenue des Martyrs, 38054 Grenoble (France)

    2008-09-01

    Several successful development programs have been conducted on infra-red bolometer arrays at the 'Commissariat a l'Energie Atomique' (CEA-LETI Grenoble) in collaboration with the CEA-SAp (Saclay); taking advantage of this background, we are now developing an X-ray spectro-imaging camera for next generation space astronomy missions, using silicon only technology. We have developed monolithic silicon micro-calorimeters based on implanted thermistors in an improved array that could be used for future space missions. The 8x8 array consists of a grid of 64 suspended pixels fabricated on a silicon on insulator (SOI) wafer. Each pixel of this detector array is made of a tantalum (Ta) absorber, which is bound by means of indium bump hybridization, to a silicon thermistor. The absorber array is bound to the thermistor array in a collective process. The fabrication process of our detector involves a combination of standard technologies and silicon bulk micro-machining techniques, based on deposition, photolithography and plasma etching steps. Finally, we present the results of measurements performed on these four primary building blocks that are required to create a detector array up to 32x32 pixels in size.

  5. Spectrally selective glazings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    Spectrally selective glazing is window glass that permits some portions of the solar spectrum to enter a building while blocking others. This high-performance glazing admits as much daylight as possible while preventing transmission of as much solar heat as possible. By controlling solar heat gains in summer, preventing loss of interior heat in winter, and allowing occupants to reduce electric lighting use by making maximum use of daylight, spectrally selective glazing significantly reduces building energy consumption and peak demand. Because new spectrally selective glazings can have a virtually clear appearance, they admit more daylight and permit much brighter, more open views to the outside while still providing the solar control of the dark, reflective energy-efficient glass of the past. This Federal Technology Alert provides detailed information and procedures for Federal energy managers to consider spectrally selective glazings. The principle of spectrally selective glazings is explained. Benefits related to energy efficiency and other architectural criteria are delineated. Guidelines are provided for appropriate application of spectrally selective glazing, and step-by-step instructions are given for estimating energy savings. Case studies are also presented to illustrate actual costs and energy savings. Current manufacturers, technology users, and references for further reading are included for users who have questions not fully addressed here.

  6. Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens.

    Science.gov (United States)

    Lucon, Enrico; McCowan, Chris N; Santoyo, Ray L

    2015-01-01

    The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of -40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots considered, the observed variability was lower at 21 °C than at -40 °C. The results of this study will allow NIST to satisfy requests for room-temperature Charpy verification specimens that have been received from customers for several years: testing at 21 °C removes from the verification process the operator's skill in transferring the specimen in a timely fashion from the cooling bath to the impact position, and puts the focus back on the machine performance. For NIST, it also reduces the time and cost for certifying new verification lots. For one of the low-energy lots tested with a C-shaped hammer, we experienced two specimens jamming, which yielded unusually high values of absorbed energy. For both specimens, the signs of jamming were clearly visible. For all the low-energy lots investigated, jamming is slightly more likely to occur at 21 °C than at -40 °C, since at room temperature low-energy samples tend to remain in the test area after impact rather than exiting in the opposite direction of the pendulum swing. In the evaluation of a verification set, any jammed specimen should be removed from the analyses.

  7. Accuracy and versatility of the NIST M48 coordinate measuring machine

    Science.gov (United States)

    Stoup, John R.; Doiron, Theodore D.

    2001-10-01

    The NIST Is continuing to develop the ability to perform accurate, traceable measurements on a wide range of artifacts using a very precise, error-mapped coordinate measuring machine (CMM). The NIST M48 CMM has promised accuracy and versatility for many ears. Recently, these promises have been realized in a reliable, reproducible way for many types of 1D, 2D, and 3D engineering metrology artifacts. The versatility of the machine has permitted state-of-the-art, accurate measurements of one meter step gages and precision ball plates as well as 500 micrometer holes and small precision parts made of aluminum or glass. To accomplish this wide range of measurements the CMM has required extensive assessment of machine positioning and straightness errors, probe response, machine motion control and speed, environmental stability, and measurement procedures. The CMM has been used as an absolute instrument and as a very complicated comparator. The data collection techniques have been designed to acquire statistical information on the machine and probe performance and to evaluate and remove any potential thermal drift in the machine coordinate system during operation. This paper will present the data collection and measurement techniques used by NIST to achieve excellent measurement results for gage blocks, long end standards, step gages, ring and plug gages, small holes, ball plates, and angular artifacts. Comparison data with existing independent primary measuring instruments will also be presented to show agreement and correlation with those historical methods. Current plans for incorporating the CMM into existing measurement services, such as plain ring gages, large plug gages, and long end standards, will be presented along with other proposed development of this CMM.

  8. Potassium Isotopic Compositions of NIST Potassium Standards and 40Ar/39Ar Mineral Standards

    Science.gov (United States)

    Morgan, Leah; Tappa, Mike; Ellam, Rob; Mark, Darren; Higgins, John; Simon, Justin I.

    2013-01-01

    Knowledge of the isotopic ratios of standards, spikes, and reference materials is fundamental to the accuracy of many geochronological methods. For example, the 238U/235U ratio relevant to U-Pb geochronology was recently re-determined [1] and shown to differ significantly from the previously accepted value employed during age determinations. These underlying values are fundamental to accurate age calculations in many isotopic systems, and uncertainty in these values can represent a significant (and often unrecognized) portion of the uncertainty budget for determined ages. The potassium isotopic composition of mineral standards, or neutron flux monitors, is a critical, but often overlooked component in the calculation of K-Ar and 40Ar/39Ar ages. It is currently assumed that all terrestrial materials have abundances indistinguishable from that of NIST SRM 985 [2]; this is apparently a reasonable assumption at the 0.25per mille level (1s) [3]. The 40Ar/39Ar method further relies on the assumption that standards and samples (including primary and secondary standards) have indistinguishable 40K/39K values. We will present data establishing the potassium isotopic compositions of NIST isotopic K SRM 985, elemental K SRM 999b, and 40Ar/39Ar biotite mineral standard GA1550 (sample MD-2). Stable isotopic compositions (41K/39K) were measured by the peak shoulder method with high resolution MC-ICP-MS (Thermo Scientific NEPTUNE Plus), using the accepted value of NIST isotopic SRM 985 [2] for fractionation [4] corrections [5]. 40K abundances were measured by TIMS (Thermo Scientific TRITON), using 41K/39K values from ICP-MS measurements (or, for SRM 985, values from [2]) for internal fractionation corrections. Collectively these data represent an important step towards a metrologically traceable calibration of 40K concentrations in primary 40Ar/39Ar mineral standards and improve uncertainties by ca. an order of magnitude in the potassium isotopic compositions of standards.

  9. TDCR and CIEMAT/NIST Liquid Scintillation Methods applied to the Radionuclide Metrology

    Science.gov (United States)

    da Cruz, P. A. L.; da Silva, C. J.; Iwahara, A.; Loureiro, J. S.; De Oliveira, A. E.; Tauhata, L.; Lopes, R. T.

    2016-07-01

    This work presents TDCR and CIEMAT/NIST methods of liquid scintillation implemented in National Institutes of Metrology for activity standardization of radionuclides, which decay by beta emission and electron capture. The computer codes used to calculate the detection efficiency take into account: decay schemes, beta decay theory, quenching parameter evaluation, Poisson statistic model and Monte Carlo simulation for photon and particle interactions in the detection system. Measurements were performed for pure emitters 3H, 14C, 99Tc and for 68Ge/68Ga which decay by electron capture and positron emission, with uncertainties smaller than 1% (k = 1).

  10. TDCR and CIEMAT/NIST liquid scintillation methods applied to the radionuclide metrology

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Paulo A.L. da; Silva, Carlos J. da; Iwahara, Akira; Loureiro, Jamir S.; Oliveira, Antonio E. de; Tauhata, Luiz, E-mail: palcruz@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lopes, Ricardo T. [Coordenacao de Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2015-07-01

    In this work are presented TDCR and CIEMAT/NIST methods of liquid scintillation implemented in National Institutes of Metrology for activity standardization of radionuclides which decay by beta emission and electron capture. The computer codes to calculate the detection efficiency take into account: decay schemes, beta decay theory, quenching parameter evaluation, Poisson statistic model and Monte Carlo simulation for photon and particle interactions in the detection system. Measurements were performed for {sup 3}H, {sup 14}C, {sup 99}Tc pure beta emitters in a large energy range, and {sup 68}Ge/{sup 68}Ga which decay by electron capture and positron emission, with uncertainties smaller than 1% (k = 1). (author)

  11. Reflective Optical Chopper Used in NIST High-Power Laser Measurements

    Directory of Open Access Journals (Sweden)

    Cromer, Chris

    2008-11-01

    Full Text Available For the past ten years, NIST has used high-reflectivity, optical choppers as beamsplitters and attenuators when calibrating the absolute responsivity and response linearity of detectors used with high-power CW lasers. The chopper-based technique has several advantages over the use of wedge-shaped transparent materials (usually crystals often used as beam splitters in this type of measurement system. We describe the design, operation and calibration of these choppers. A comparison between choppers and transparent wedge beampslitters is also discussed.

  12. Update of NIST half-life results corrected for ionization chamber source-holder instability.

    Science.gov (United States)

    Unterweger, M P; Fitzgerald, R

    2014-05-01

    As reported at the ICRM 2011, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) was not stable. This has affected a large number of half-life measurement results previously reported and used in compilations of nuclear data. Corrections have been made on all of the half-life data based on the assumption that the changes to the ionization chamber response were gradual. The corrections are energy dependent and therefore radionuclide specific. This presentation will review our results and present the recommended changes in half-life values and/or uncertainties.

  13. Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens

    OpenAIRE

    Lucon, Enrico; McCowan, Chris N.; Santoyo, Ray L.

    2015-01-01

    The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of −40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots ...

  14. Certification of NIST SRM 1961: 30 μm Diameter Polystyrene Spheres

    Science.gov (United States)

    Hartman, Arie W.; Doiron, Theodore D.; Hembree, Gary G.

    1991-01-01

    This report describes the certification of SRM 1961, an NIST Standard Reference Material for particle diameter. It consists of an aqueous suspension of monosize 30 μm diameter polystyrene spheres. The primary technique used optical microscopy; it gave a mean diameter value D¯=29.62±0.04μm and a standard deviation of the size distribution σD = 0.21 μm. Over 2000 spheres were measured. The supporting technique used electron microscopy, which yielded D¯=29.68±0.11μm. Ninety spheres were measured.

  15. HAPPY Team Entry to NIST OpenSAD Challenge: A Fusion of Short-Term Unsupervised and Segment i-Vector Based Speech Activity Detectors

    DEFF Research Database (Denmark)

    Kinnunen, Tomi; Sholokhov, Alexey; Khoury, Elie

    2016-01-01

    . SADs come in both unsupervised and supervised flavors, the latter requiring a labeled training set. Our solution fuses six base SADs (2 supervised and 4 unsupervised). The individually best SAD, in terms of detection cost function (DCF), is supervised and uses adaptive segmentation with i......Speech activity detection (SAD), the task of locating speech segments from a given recording, remains challenging under acoustically degraded conditions. In 2015, National Institute of Standards and Technology (NIST) coordinated OpenSAD bench-mark. We summarize “HAPPY” team effort to Open- SAD......-vectors to represent the segments. Fusion of the six base SADs yields a relative decrease of 9.3 % in DCF over this SAD. Further, relative decrease of 17.4 % is obtained by incorporating channel detection side information....

  16. Spectral Analysis

    CERN Document Server

    Cecconi, Jaures

    2011-01-01

    G. Bottaro: Quelques resultats d'analyse spectrale pour des operateurs differentiels a coefficients constants sur des domaines non bornes.- L. Garding: Eigenfuction expansions.- C. Goulaouic: Valeurs propres de problemes aux limites irreguliers: applications.- G. Grubb: Essential spectra of elliptic systems on compact manifolds.- J.Cl. Guillot: Quelques resultats recents en Scattering.- N. Schechter: Theory of perturbations of partial differential operators.- C.H. Wilcox: Spectral analysis of the Laplacian with a discontinuous coefficient.

  17. A comparative study of (129)I content in environmental standard materials IAEA-375, NIST SRM 4354 and NIST SRM 4357 by Thermal Ionization Mass Spectrometry and Accelerator Mass Spectrometry.

    Science.gov (United States)

    Olson, John; Adamic, Mary; Snyder, Darin; Brookhart, Jacob; Hahn, Paula; Watrous, Matthew

    2017-01-25

    Iodine environmental measurements have consistently been validated in the literature using the standard material IAEA-375, soil collected approximately 160 miles northeast of Chernobyl, which is currently the only soil/sediment material with a certified (129)I activity. IAEA-375 has not been available for purchase since approximately 2010. Two other standard materials that are available (NIST SRM 4354, freshwater lake sediment and NIST SRM 4357, ocean sediment) have certified activities for a variety of radionuclides but not for (129)I. This paper reports a comparison of TIMS and AMS data for all three standards.

  18. Thermophotovoltaic Spectral Control

    Energy Technology Data Exchange (ETDEWEB)

    DM DePoy; PM Fourspring; PF Baldasaro; JF Beausang; EJ Brown; MW Dashiel; KD Rahner; TD Rahmlow; JE Lazo-Wasem; EJ Gratrix; B Wemsman

    2004-06-09

    Spectral control is a key technology for thermophotovoltaic (TPV) direct energy conversion systems because only a fraction (typically less than 25%) of the incident thermal radiation has energy exceeding the diode bandgap energy, E{sub g}, and can thus be converted to electricity. The goal for TPV spectral control in most applications is twofold: (1) Maximize TPV efficiency by minimizing transfer of low energy, below bandgap photons from the radiator to the TPV diode. (2) Maximize TPV surface power density by maximizing transfer of high energy, above bandgap photons from the radiator to the TPV diode. TPV spectral control options include: front surface filters (e.g. interference filters, plasma filters, interference/plasma tandem filters, and frequency selective surfaces), back surface reflectors, and wavelength selective radiators. System analysis shows that spectral performance dominates diode performance in any practical TPV system, and that low bandgap diodes enable both higher efficiency and power density when spectral control limitations are considered. Lockheed Martin has focused its efforts on front surface tandem filters which have achieved spectral efficiencies of {approx}83% for E{sub g} = 0.52 eV and {approx}76% for E{sub g} = 0.60 eV for a 950 C radiator temperature.

  19. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  20. Spectral Ranking

    CERN Document Server

    Vigna, Sebastiano

    2009-01-01

    This note tries to attempt a sketch of the history of spectral ranking, a general umbrella name for techniques that apply the theory of linear maps (in particular, eigenvalues and eigenvectors) to matrices that do not represent geometric transformations, but rather some kind of relationship between entities. Albeit recently made famous by the ample press coverage of Google's PageRank algorithm, spectral ranking was devised more than fifty years ago, almost exactly in the same terms, and has been studied in psychology and social sciences. I will try to describe it in precise and modern mathematical terms, highlighting along the way the contributions given by previous scholars.

  1. NIST ThermoData Engine: Extension to Solvent Design and Propagation of Uncertainties for Process Simulation

    DEFF Research Database (Denmark)

    Diky, Vladimir; Chirico, Robert D.; Muzny, Chris

    property values and expert system for data analysis and generation of recommended property values at the specified conditions along with uncertainties on demand. The most recent extension of TDE covers solvent design and multi-component process stream property calculations with uncertainty analysis......ThermoData Engine (TDE, NIST Standard Reference Databases 103a and 103b) is the first product that implements the concept of Dynamic Data Evaluation in the fields of thermophysics and thermochemistry, which includes maintaining the comprehensive and up-to-date database of experimentally measured....... Solvent Design function serves three tasks: (1) selection of best solvent for a solid solute, (2) search for a selective solvent for a solid binary mixture, and (3) selection of best solvent for extraction. Solvents are selected from the list of registered compounds encountering more than 27,000 entries...

  2. Frequency shifts in NIST Cs Primary Frequency Standards due To Transverse RF Field Gradients

    CERN Document Server

    Ashby, Neil; Heavner, Thomas; Jefferts, Steven

    2014-01-01

    A single-particle Green's function (propagator) is introduced to study the detection of laser-cooled Cesium atoms in an atomic fountain due to RF ?field gradients in the Ramsey TE011 cavity. The detection results in a state-dependent loss of atoms at apertures in the physics package, resulting in a frequency bias. A model accounting only for motion in one dimension transverse to the symmetry axis of the fountain is discussed in detail and then generalized to two transverse dimensions. Results for fractional frequency shifts due to transverse field gradients are computed for NIST F-1 and F-2 Cesium fountains. The shifts are found to be negligible except in cases of higher RF power applied to the cavities.

  3. Optical design and initial results from NIST's AMMT/TEMPS facility

    Science.gov (United States)

    Grantham, Steven; Lane, Brandon; Neira, Jorge; Mekhontsev, Sergey; Vlasea, Mihaela; Hanssen, Leonard

    2016-05-01

    NIST's Physical Measurement and Engineering Laboratories are jointly developing the Additive Manufacturing Measurement Test bed (AMMT)/ Temperature and Emittance of Melts, Powders and Solids (TEMPS) facilities. These facilities will be co-located on an open architecture laser-based powder bed fusion system allowing users full access to the system's operation parameters. This will provide users with access to machine-independent monitoring and control of the powder bed fusion process. In this paper there will be emphasis on the AMMT, which incorporates in-line visible light collection optics for monitoring and feedback control of the powder bed fusion process. We shall present an overview of the AMMT/TEMPs program and it goals. The optical and mechanical design of the open architecture powder-bed fusion system and the AMMT will be also be described. In addition, preliminary measurement results from the system along with the current system status of the system the will be described.

  4. Controlled deposition of NIST-traceable nanoparticles as additional size standards for photomask applications

    Science.gov (United States)

    Wang, Jing; Pui, David Y. H.; Qi, Chaolong; Yook, Se-Jin; Fissan, Heinz; Ultanir, Erdem; Liang, Ted

    2008-03-01

    Particle standard is important and widely used for calibration of inspection tools and process characterization and benchmarking. We have developed a method for generating and classifying monodisperse particles of different materials with a high degree of control. The airborne particles are first generated by an electrospray. Then a tandem Differential Mobility Analyzer (TDMA) system is used to obtain monodisperse particles with NIST-traceable sizes. We have also developed a clean and well-controlled method to deposit airborne particles on mask blanks or wafers. This method utilizes electrostatic approach to deposit particles evenly in a desired spot. Both the number of particles and the spot size are well controlled. We have used our system to deposit PSL, silica and gold particles ranging from 30 nm to 125 nm on 193nm and EUV mask blanks. We report the experimental results of using these particles as calibration standards and discuss the dependency of sensitivity on the types of particles and substrate surfaces.

  5. The NIST Real-Time Control System (RCS): A Reference Model Architecture for Computational Intelligence

    Science.gov (United States)

    Albus, James S.

    1996-01-01

    The Real-time Control System (RCS) developed at NIST and elsewhere over the past two decades defines a reference model architecture for design and analysis of complex intelligent control systems. The RCS architecture consists of a hierarchically layered set of functional processing modules connected by a network of communication pathways. The primary distinguishing feature of the layers is the bandwidth of the control loops. The characteristic bandwidth of each level is determined by the spatial and temporal integration window of filters, the temporal frequency of signals and events, the spatial frequency of patterns, and the planning horizon and granularity of the planners that operate at each level. At each level, tasks are decomposed into sequential subtasks, to be performed by cooperating sets of subordinate agents. At each level, signals from sensors are filtered and correlated with spatial and temporal features that are relevant to the control function being implemented at that level.

  6. Certification of NIST SRM 1962: 3 μm Diameter Polystyrene Spheres

    Science.gov (United States)

    Hartman, Arie W.; Doiron, Theodore D.; Fu, Joseph

    1992-01-01

    This report describes the certification of SRM 1962, a NIST Standard Reference Material for particle diameter. It consists of an aqueous suspension of monosize 3 (μm polystyrene spheres. Two calibration techniques were used: optical microscopy and electron microscopy. The first one gave a mean diameter of D¯=2.977±0.011 μm and a standard deviation of the size distribution σD = 0.020 μm, based on measurement of 4600 spheres. The second technique gave D¯=2.990±0.009 μm, based on measurement of 120 spheres. The reported value covering the two results is D¯=2.983 μm with a maximum uncertainly of 0.016 μm, with σD=0.020 μm. PMID:28053431

  7. Measurements of large silicon spheres using the NIST M48 coordinate measuring machine

    Science.gov (United States)

    Stoup, John; Doiron, Theodore

    2003-11-01

    The NIST M48 coordinate measuring machine (CMM) was used to measure the average diameter of two precision, silicon spheres of nominal diameter near 93.6mm. A measurement technique was devised that took advantage of the specific strengths of the machine and the artifacts while restricting the influences derived from the machine's few weaknesses. This effort resulted in measurements with unprecedented accuracy and uncertainty levels for CMM style instruments. The results were confirmed through a blind comparison with another national measurement institute (NMI) that used special apparatus specifically designed for the measurement of these silicon spheres and employed very different measurement techniques. The standard uncertainty of the average diameter measurements was less than 20 nanometers. This paper will describe the measurement techniques along with the decision-making processes used to develop these specific methods. The measurement uncertainty of the measurements will also be rigorously examined.

  8. Unexpected bias in NIST 4πγ ionization chamber measurements.

    Science.gov (United States)

    Unterweger, M P; Fitzgerald, R

    2012-09-01

    In January of 2010, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) has not been stable. The positioning ring that determines the height of the sample in the reentrant tube of the IC has slowly shifted during 35 years of use. This has led to a slow change in the calibration factors for the various radionuclides measured by this instrument. The changes are dependent on γ-ray energy and the time the IC was calibrated for a given radionuclide. A review of the historic data with regard to when the calibrations were done has enabled us to approximate the magnitude of the changes with time. This requires a number of assumptions, and corresponding uncertainty components, including whether the changes in height were gradual or in steps as will be shown in drawings of sample holder. For calibrations the changes in calibration factors have been most significant for low energy gamma emitters such as (133)Xe, (241)Am, (125)I and (85)Kr. The corrections to previous calibrations can be approximated and the results corrected with an increase in the overall uncertainty. At present we are recalibrating the IC based on new primary measurements of the radionuclides measured on the IC. Likewise we have been calibrating a new automated ionization-chamber system. A bigger problem is the significant number of half-life results NIST has published over the last 35 years that are based on IC measurements. The effect on half-life is largest for long-lived radionuclei, especially low-energy γ-ray emitters. This presentation will review our results and recommend changes in values and/or uncertainties. Any recommendation for withdrawal of any results will also be undertaken.

  9. Simulation evaluation of NIST air-kerma rate calibration standard for electronic brachytherapy.

    Science.gov (United States)

    Hiatt, Jessica R; Rivard, Mark J; Hughes, H Grady

    2016-03-01

    Dosimetry for the model S700 50 kV electronic brachytherapy (eBT) source (Xoft, Inc., a subsidiary of iCAD, San Jose, CA) was simulated using Monte Carlo (MC) methods by Rivard et al. ["Calculated and measured brachytherapy dosimetry parameters in water for the Xoft Axxent x-ray source: An electronic brachytherapy source," Med. Phys. 33, 4020-4032 (2006)] and recently by Hiatt et al. ["A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model," Med. Phys. 42, 2764-2776 (2015)] with improved geometric characterization. While these studies examined the dose distribution in water, there have not previously been reports of the eBT source calibration methods beyond that recently reported by Seltzer et al. ["New national air-kerma standard for low-energy electronic brachytherapy sources," J. Res. Natl. Inst. Stand. Technol. 119, 554-574 (2014)]. Therefore, the motivation for the current study was to provide an independent determination of air-kerma rate at 50 cm in air K̇air(d=50 cm) using MC methods for the model S700 eBT source. Using CAD information provided by the vendor and disassembled sources, an MC model was created for the S700 eBT source. Simulations were run using the mcnp6 radiation transport code for the NIST Lamperti air ionization chamber according to specifications by Boutillon et al. ["Comparison of exposure standards in the 10-50 kV x-ray region," Metrologia 5, 1-11 (1969)], in air without the Lamperti chamber, and in vacuum without the Lamperti chamber. K̇air(d=50 cm) was determined using the *F4 tally with NIST values for the mass energy-absorption coefficients for air. Photon spectra were evaluated over 2 π azimuthal sampling for polar angles of 0° ≤ θ ≤ 180° every 1°. Volume averaging was averted through tight radial binning. Photon energy spectra were determined over all polar angles in both air and vacuum using

  10. The Application of Spectral Unmixing Technology for Lunar Regolith%用于月球风化层遥感的光谱分离技术研究

    Institute of Scientific and Technical Information of China (English)

    薛彬; 杨建峰; 赵葆常

    2005-01-01

    Spectral unmixing technology has been developed to solve mixing pixel problem, the linear mixing model is more successful to this day. But when applied to the lunar regolith, it would have two limitations: the nonlinerity of intimate mixture and the error caused by the lack of endmember spectra. As to the former, simpled multiple scattering model based on Hapke's theory is developed to improve the linearity of intimate mixture and reduce computational complexity; as to the latter, Modified Linear Mixing Model (MLMM) is advanced to compensate for the error in endmember spectra. The motheds are test by the simulated lunar soils' spectra data gained from the Relab, the experimental result display their good performances.%为了解决混合像元问题,发展了一门新的技术--光谱分离技术,线形混合模型是目前应用最成功的方法,但是当应用到月球风化层遥感时,其存在两个内在的缺陷:一是由于充分混合引起的非线性,二是纯光谱的不"纯"性.对于第一个缺陷,从Hapke理论出发,充分考虑了数据的特点,大大简化多重散射模型来提高充分混合的线形性,同时降低了原模型计算的复杂度;对于后一个问题,提出用修正线形混合模型来弥补"纯"光谱中的误差.该方法通过Relab数据库中的模拟月壤的光谱数据进行了验证,试验结果表明,这种方法具有很好的性能.

  11. Spectral Tagging

    Energy Technology Data Exchange (ETDEWEB)

    Smartt, Heidi A. [Sandia National Laboratories (United States)

    2003-05-01

    This research examines the feasibility of spectral tagging, which involves modifying the spectral signature of a target, e.g. by mixing an additive with the target's paint. The target is unchanged to the human eye, but the tag is revealed when viewed with a spectrometer. This project investigates a layer of security that is not obvious, and therefore easy to conceal. The result is a tagging mechanism that is difficult to counterfeit. Uniquely tagging an item is an area of need in safeguards and security and non-proliferation. The powdered forms of the minerals lapis lazuli and olivine were selected as the initial test tags due to their availability and uniqueness in the visible to near-infrared spectral region. They were mixed with paints and applied to steel. In order to verify the presence of the tags quantitatively, the data from the spectrometer was input into unmixing models and signal detection algorithms. The mixture with the best results was blue paint mixed with lapis lazuli and olivine. The tag had a 0% probability of false alarm and a 100% probability of detection. The research proved that spectral tagging is feasible, although certain tag/paint mixtures are more detectable than others.

  12. 75 FR 21232 - FY 2010 NIST Center for Neutron Research (NCNR) Comprehensive Grants Program Extension of Due...

    Science.gov (United States)

    2010-04-23

    ... ] Research, conducting collaborative research with NIST scientists, and to conduct other outreach and...'' regulatory action under Section 3(f)(1) of the Executive Order, as it does not have an effect on the economy... economy, a sector of the economy, productivity, competition, jobs, the environment, public health or...

  13. Computational Fluid Dynamics Modeling of a wood-burning stove-heated sauna using NIST's Fire Dynamics Simulator

    CERN Document Server

    Macqueron, Corentin

    2014-01-01

    The traditional sauna is studied from a thermal and fluid dynamics standpoint using the NIST's Fire Dynamics Simulator (FDS) software. Calculations are performed in order to determine temperature and velocity fields, heat flux, soot and steam cloud transport, etc. Results are discussed in order to assess the reliability of this new kind of utilization of the FDS fire safety engineering software.

  14. 78 FR 63964 - Request for Comments on Draft NIST Interagency Report (NISTIR) 7628 Rev. 1, Guidelines for Smart...

    Science.gov (United States)

    2013-10-25

    ... (NISTIR) 7628 Rev. 1, Guidelines for Smart Grid Cyber Security AGENCY: National Institute of Standards and... Smart Grid Cyber Security. Draft NISTIR 7628 Rev. 1 was completed by the NIST-led Smart Grid Cybersecurity Committee (formerly the Cyber Security Working Group) of the Smart Grid Interoperability...

  15. 75 FR 33268 - Technology Innovation Program (TIP) Notice of Availability of Funds; Amendment

    Science.gov (United States)

    2010-06-11

    ... National Institute of Standards and Technology Technology Innovation Program (TIP) Notice of Availability... solicitation of proposals for the fiscal year 2010 Technology Innovation Program (TIP) competition. NIST is... National Institute of Standards and Technology, Technology Innovation Program, 100 Bureau Drive, Stop 4750...

  16. Mass Spectral Library Quality Assurance by Inter-Library Comparison

    Science.gov (United States)

    Wallace, William E.; Ji, Weihua; Tchekhovskoi, Dmitrii V.; Phinney, Karen W.; Stein, Stephen E.

    2017-01-01

    A method to discover and correct errors in mass spectral libraries is described. Comparing across a set of highly curated reference libraries compounds that have the same chemical structure quickly identifies entries that are outliers. In cases where three or more entries for the same compound are compared, the outlier as determined by visual inspection was almost always found to contain the error. These errors were either in the spectrum itself or in the chemical descriptors that accompanied it. The method is demonstrated on finding errors in compounds of forensic interest in the NIST/EPA/NIH Mass Spectral Library. The target list of compounds checked was the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) mass spectral library. Some examples of errors found are described. A checklist of errors that curators should look for when performing inter-library comparisons is provided.

  17. Spectral Predictors

    Energy Technology Data Exchange (ETDEWEB)

    Ibarria, L; Lindstrom, P; Rossignac, J

    2006-11-17

    Many scientific, imaging, and geospatial applications produce large high-precision scalar fields sampled on a regular grid. Lossless compression of such data is commonly done using predictive coding, in which weighted combinations of previously coded samples known to both encoder and decoder are used to predict subsequent nearby samples. In hierarchical, incremental, or selective transmission, the spatial pattern of the known neighbors is often irregular and varies from one sample to the next, which precludes prediction based on a single stencil and fixed set of weights. To handle such situations and make the best use of available neighboring samples, we propose a local spectral predictor that offers optimal prediction by tailoring the weights to each configuration of known nearby samples. These weights may be precomputed and stored in a small lookup table. We show that predictive coding using our spectral predictor improves compression for various sources of high-precision data.

  18. Study on the ICT Supply Chain Risk Management Standard—NIST SP800-161%ICT供应链风险管理标准NIST SP800-161探析

    Institute of Scientific and Technical Information of China (English)

    董坤祥; 谢宗晓

    2015-01-01

    本文分析了美国联邦信息系统和组织的供应链风险管理实践指导草案,并从ICT供应链风险管理的目标、应用范围、制定背景、实践和标准形成五个方面探讨了NIST SP 800-161的主要内容.最后提出了ICT供应链风险管理标准在新背景下需完善的几个方面.%We analyze the draft of Supply Chain Risk Management Practices for Federal Information Systems and Organizations. Then, we discuss the content of NIST SP800-161 in five aspects: purpose, scope, background, foundational practice and standard formation of ICT SCRM. Finally, we purpose the several aspects need to be improved in ICT SCRM standards.

  19. Development of NIST standard reference material 2373: Genomic DNA standards for HER2 measurements

    Directory of Open Access Journals (Sweden)

    Hua-Jun He

    2016-06-01

    Full Text Available NIST standard reference material (SRM 2373 was developed to improve the measurements of the HER2 gene amplification in DNA samples. SRM 2373 consists of genomic DNA extracted from five breast cancer cell lines with different amounts of amplification of the HER2 gene. The five components are derived from the human cell lines SK-BR-3, MDA-MB-231, MDA-MB-361, MDA-MB-453, and BT-474. The certified values are the ratios of the HER2 gene copy numbers to the copy numbers of selected reference genes DCK, EIF5B, RPS27A, and PMM1. The ratios were measured using quantitative polymerase chain reaction and digital PCR, methods that gave similar ratios. The five components of SRM 2373 have certified HER2 amplification ratios that range from 1.3 to 17.7. The stability and homogeneity of the reference materials were shown by repeated measurements over a period of several years. SRM 2373 is a well characterized genomic DNA reference material that can be used to improve the confidence of the measurements of HER2 gene copy number.

  20. A comparative study of 129I content in environmental standard materials IAEA-375, NIST SRM 4354 and NIST SRM 4357 by Thermal Ionization Mass Spectrometry and Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Olson, John; Adamic, Mary; Snyder, Darin; Brookhart, Jacob; Hahn, Paula; Watrous, Matthew

    2016-11-01

    Iodine environmental measurements have consistently been backed up in the literature by standard materials like IAEA-375, Chernobyl Soil. There are not many other sources of a certified reference material for 129I content for mass spectrometry measurements. Some that have been found in the literature include NIST-4354 and NIST-4357. They are still available at the time of this writing. They don’t have certified content or isotopic values. There has been some work in the literature to show that iodine is present, but there hasn’t been enough to establish a consensus value. These materials have been analyzed at INL through two separate mass spectrometry techniques. They involve a combustion method of the starting material in oxygen, followed by TIMS analysis and a leaching preparation analyzed by accelerator mass spectrometry. Combustion/TIMS preparation of NIST SRM-4354 resulted in a 129I/127I ratio of 1.92 x 10-6 which agrees with AMS measurements which measured the 129I/127I ratio to be 1.93 x 10-6.

  1. A Comparison of Contemporary Gold Versus Platinum Thermocouples with NIST SRM 1749-Based Thermocouples and Reference Function

    Science.gov (United States)

    Coleman, M. J.; Wiandt, T. J.; Harper, T.

    2015-12-01

    Fluke Calibration (formerly Hart Scientific) in American Fork, Utah, USA is a manufacturer of temperature calibration instruments. The company manufactured reference standard gold versus platinum (Au-Pt) thermocouples from 1992 to about 2002. Manufacturing was halted in 2002 because a trend of poor curve-fit results was observed in new batches of wire. After reviewing the possible sources of the problem, it was decided to sample wire from multiple manufacturers and investigate ways to make the curve-fit work better. This paper presents the results from the study of the wire and a characterization technique to help improve characterization of thermocouples made with lower purity wire. Calibration results from NIST SRM material and older Fluke thermocouples are included as well to provide a means of comparison of contemporary wire to NIST SRM era wire.

  2. Results and Systematic Studies of the UCN Lifetime Experiment at NIST

    Science.gov (United States)

    Huffer, Craig Reeves

    The neutron beta-decay lifetime is important in understanding weak interactions in the framework of the Standard Model, and it is an input to nuclear astrophysics and Big Bang Nucleosynthesis. Current measurements of the neutron beta-decay lifetime disagree, which has motivated additional experiments that are sensitive to different sets of systematic effects. An effort continues at the NIST Center for Neutron Research (NCNR) to improve the statistical and systematic limitations of an experiment to measure the neutron beta-decay lifetime using magnetically trapped UCN. In the experiment, a monoenergetic 0:89 nm cold neutron is incident on a superfluid 4He target within the minimum field region of an Ioffe type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (≈ 200 neV), and those in the appropriate spin state become trapped. The inverse process, upscattering of UCN, is suppressed by the low phonon density in the transported out of the cell to PMTs operated at room temperature. With this method, the decay of the UCN population can be monitored in situ. The apparatus, analysis, data, and systematics will be discussed. After accounting for the systematic effects the measured lifetime disagrees with the current PDG mean neutron beta-decay lifetime by about 9 of our standard deviations, which is a strong indication of unaccounted for systematic effects. Additional 3He contamination will be shown to be the most likely candidate for the additional systematic shift, which motivated the commissioning and initial operation of a heat flush purifier for purifying additional 4He. This work ends with a description of the 4He purifier and its performance.

  3. Temperature measurements at the National Institute of Standards and Technology

    Science.gov (United States)

    Mangum, B. W.

    The high-precision and high-accuracy measurements involved in the calibrations of various types of thermometers at the National Institute of Standards and Technology (NIST) are described. The responsibilities of the NIST Thermometry Group include not only calibration of the standard instruments of the scales but also the calibration of base-metal and noble-metal thermocouples, industrial platinum resistance thermometers, liquid in-glass thermometers, thermistor thermometers, and digital thermometers. General laboratory thermometer calibrations are described. Also, a Measurement Assurance Program is described which provides a direct assessment of a customer's technological competence in thermometry.

  4. 76 FR 3877 - Effectiveness of Federal Agency Participation in Standardization in Select Technology Sectors for...

    Science.gov (United States)

    2011-01-21

    ... Standardization in Select Technology Sectors for National Science and Technology Council's Sub-Committee on Standardization; Extension of Comment Period AGENCY: National Institute of Standards and Technology, U.S..._RFI@nist.gov with the subject line ``Standardization feedback for Sub-Committee on Standards.''...

  5. Quantum Spectral Imaging Technology and Its Prospect in Earth Observation Application%量子光谱成像技术及其在对地观测中的应用前景

    Institute of Scientific and Technical Information of China (English)

    唐晓燕; 高昆; 倪国强

    2011-01-01

    The development of quantum spectral imaging technology is summarized at first. Its fundamental theory is introduced briefly. The relative phenomena and experiments are illustrated such as two-photon entanglement ghost imaging, sub-wavelength interference, near-field lensless ghost imaging and nonlocal double-slit interference with thermal light. The future development of quantum spectral imaging technology and its future application are prospected in both the military and the civil earth observation fields.%综述了量子光谱成像技术的发展概况,简述了量子光谱成像原理的理论,详细介绍了纠缠双光子源的鬼成像,亚波长干涉以及热光的无透镜成像和热光的非定域双缝干涉实验及其原理。最后对量子光谱成像技术在未来的军用和民用对地观测的应用方面做出了展望。

  6. Liquid scintillation counting standardization of 125I in organic and inorganic samples by the CIEMAT/NIST method; Calibracion por centelleo liquido del 125I en muestras inorganicas y organicas, mediante el metodo CIEMAT/NIST

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J. M.; Grau Carles, A.

    1994-07-01

    The liquid scintillation counting standardization of organic and inorganic samples of ''I25I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%. (Author) 14 refs.

  7. A spectral invariant representation of spectral reflectance

    Science.gov (United States)

    Ibrahim, Abdelhameed; Tominaga, Shoji; Horiuchi, Takahiko

    2011-03-01

    Spectral image acquisition as well as color image is affected by several illumination factors such as shading, gloss, and specular highlight. Spectral invariant representations for these factors were proposed for the standard dichromatic reflection model of inhomogeneous dielectric materials. However, these representations are inadequate for other characteristic materials like metal. This paper proposes a more general spectral invariant representation for obtaining reliable spectral reflectance images. Our invariant representation is derived from the standard dichromatic reflection model for dielectric materials and the extended dichromatic reflection model for metals. We proof that the invariant formulas for spectral images of natural objects preserve spectral information and are invariant to highlights, shading, surface geometry, and illumination intensity. It is proved that the conventional spectral invariant technique can be applied to metals in addition to dielectric objects. Experimental results show that the proposed spectral invariant representation is effective for image segmentation.

  8. Analysis of Pipeline Steel Corrosion Data From NBS (NIST) Studies Conducted Between 1922-1940 and Relevance to Pipeline Management.

    Science.gov (United States)

    Ricker, Richard E

    2010-01-01

    Between 1911 and 1984, the National Bureau of Standards (NBS) conducted a large number of corrosion studies that included the measurement of corrosion damage to samples exposed to real-world environments. One of these studies was an investigation conducted between 1922 and 1940 into the corrosion of bare steel and wrought iron pipes buried underground at 47 different sites representing different soil types across the Unites States. At the start of this study, very little was known about the corrosion of ferrous alloys underground. The objectives of this study were to determine (i) if coatings would be required to prevent corrosion, and (ii) if soil properties could be used to predict corrosion and determine when coatings would be required. While this study determined very quickly that coatings would be required for some soils, it found that the results were so divergent that even generalities based on this data must be drawn with care. The investigators concluded that so many diverse factors influence corrosion rates underground that planning of proper tests and interpretation of the results were matters of considerable difficulty and that quantitative interpretations or extrapolations could be done "only in approximate fashion" and attempted only in the "restricted area" of the tests until more complete information is available. Following the passage of the Pipeline Safety Improvement Act in 2002 and at the urging of the pipeline industry, the Office of Pipeline Safety of the U.S. Department of Transportation approached the National Institute of Standards and Technology (NBS became NIST in 1988) and requested that the data from this study be reexamined to determine if the information handling and analysis capabilities of modern computers and software could enable the extraction of more meaningful information from these data. This report is a summary of the resulting investigations. The data from the original NBS studies were analyzed using a variety of

  9. Analysis of Pipeline Steel Corrosion Data From NBS (NIST) Studies Conducted Between 1922–1940 and Relevance to Pipeline Management

    Science.gov (United States)

    Ricker, Richard E.

    2010-01-01

    Between 1911 and 1984, the National Bureau of Standards (NBS) conducted a large number of corrosion studies that included the measurement of corrosion damage to samples exposed to real-world environments. One of these studies was an investigation conducted between 1922 and 1940 into the corrosion of bare steel and wrought iron pipes buried underground at 47 different sites representing different soil types across the Unites States. At the start of this study, very little was known about the corrosion of ferrous alloys underground. The objectives of this study were to determine (i) if coatings would be required to prevent corrosion, and (ii) if soil properties could be used to predict corrosion and determine when coatings would be required. While this study determined very quickly that coatings would be required for some soils, it found that the results were so divergent that even generalities based on this data must be drawn with care. The investigators concluded that so many diverse factors influence corrosion rates underground that planning of proper tests and interpretation of the results were matters of considerable difficulty and that quantitative interpretations or extrapolations could be done “only in approximate fashion” and attempted only in the “restricted area” of the tests until more complete information is available. Following the passage of the Pipeline Safety Improvement Act in 2002 and at the urging of the pipeline industry, the Office of Pipeline Safety of the U.S. Department of Transportation approached the National Institute of Standards and Technology (NBS became NIST in 1988) and requested that the data from this study be reexamined to determine if the information handling and analysis capabilities of modern computers and software could enable the extraction of more meaningful information from these data. This report is a summary of the resulting investigations. The data from the original NBS studies were analyzed using a variety of

  10. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  11. Testing an alternative search algorithm for compound identification with the 'Wiley Registry of Tandem Mass Spectral Data, MSforID'.

    Science.gov (United States)

    Oberacher, Herbert; Whitley, Graeme; Berger, Bernd; Weinmann, Wolfgang

    2013-04-01

    A tandem mass spectral database system consists of a library of reference spectra and a search program. State-of-the-art search programs show a high tolerance for variability in compound-specific fragmentation patterns produced by collision-induced decomposition and enable sensitive and specific 'identity search'. In this communication, performance characteristics of two search algorithms combined with the 'Wiley Registry of Tandem Mass Spectral Data, MSforID' (Wiley Registry MSMS, John Wiley and Sons, Hoboken, NJ, USA) were evaluated. The search algorithms tested were the MSMS search algorithm implemented in the NIST MS Search program 2.0g (NIST, Gaithersburg, MD, USA) and the MSforID algorithm (John Wiley and Sons, Hoboken, NJ, USA). Sample spectra were acquired on different instruments and, thus, covered a broad range of possible experimental conditions or were generated in silico. For each algorithm, more than 30,000 matches were performed. Statistical evaluation of the library search results revealed that principally both search algorithms can be combined with the Wiley Registry MSMS to create a reliable identification tool. It appears, however, that a higher degree of spectral similarity is necessary to obtain a correct match with the NIST MS Search program. This characteristic of the NIST MS Search program has a positive effect on specificity as it helps to avoid false positive matches (type I errors), but reduces sensitivity. Thus, particularly with sample spectra acquired on instruments differing in their setup from tandem-in-space type fragmentation, a comparably higher number of false negative matches (type II errors) were observed by searching the Wiley Registry MSMS.

  12. Technology.

    Science.gov (United States)

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  13. Spectral responsivity calibrations of two types of pyroelectric radiometers using three different methods

    Science.gov (United States)

    Zeng, J.; Eppeldauer, G. P.; Hanssen, L. M.; Podobedov, V. B.

    2012-06-01

    Spectral responsivity calibrations of two different types of pyroelectric radiometers have been made in the infrared region up to 14 μm in power mode using three different calibration facilities at NIST. One pyroelectric radiometer is a temperature-controlled low noise-equivalent-power (NEP) single-element pyroelectric radiometer with an active area of 5 mm in diameter. The other radiometer is a prototype using the same type of pyroeletric detector with dome-input optics, which was designed to increase absorptance and to minimize spectral structures to obtain a constant spectral responsivity. Three calibration facilities at NIST were used to conduct direct and indirect responsivity calibrations tied to absolute scales in the infrared spectral regime. We report the calibration results for the single-element pyroelectric radiometer using a new Infrared Spectral Comparator Facility (IRSCF) for direct calibration. Also, a combined method using the Fourier Transform Infrared Spectrophotometry (FTIS) facility and single wavelength laser tie-points are described to calibrated standard detectors with an indirect approach. For the dome-input pyroelectric radiometer, the results obtained from another direct calibration method using a circular variable filter (CVF) spectrometer and the FTIS are also presented. The inter-comparison of different calibration methods enables us to improve the responsivity uncertainty performed by the different facilities. For both radiometers, consistent results of the spectral power responsivity have been obtained applying different methods from 1.5 μm to 14 μm with responsivity uncertainties between 1 % and 2 % (k = 2). Relevant characterization results, such as spatial uniformity, linearity, and angular dependence of responsivity, are shown. Validation of the spectral responsivity calibrations, uncertainty sources, and improvements for each method will also be discussed.

  14. Quantum Spectral Symmetries

    Science.gov (United States)

    Hamhalter, Jan; Turilova, Ekaterina

    2017-02-01

    Quantum symmetries of spectral lattices are studied. Basic properties of spectral order on A W ∗-algebras are summarized. Connection between projection and spectral automorphisms is clarified by showing that, under mild conditions, any spectral automorphism is a composition of function calculus and Jordan ∗-automorphism. Complete description of quantum spectral symmetries on Type I and Type II A W ∗-factors are completely described.

  15. Evaluation of the Homogeneity of the Uranium Isotope Composition of NIST SRM 610/611 by MC-ICP-MS, MC-TIMS, and SIMS

    Directory of Open Access Journals (Sweden)

    Mindy M. Zimmer

    2014-06-01

    Full Text Available As analytical and microanalytical applications employing uranium isotope ratios increase, so does the need for reliable reference materials, particularly in the fields of geochemistry, geochronology, and nuclear forensics. We present working values for uranium isotopic data of NIST 610/611 glass, collected by multicollector inductively-coupled plasma mass spectrometry (MC-ICP-MS, multicollector thermal ionization mass spectrometry (MC-TIMS, and secondary ion mass spectrometry (SIMS. The presence of depleted U, and, in this case, measureable 236U, makes NIST 610/611 an ideal candidate for a uranium isotopic reference material for nuclear materials. We analyzed multiple chips of three different NIST 611 wafers and found no heterogeneity in 234U/238U, 235U/238U, and 236U/238U within or between the wafers, within analytical uncertainty. We determined working values and uncertainties (using a coverage factor of two using data from this study and the literature for the following U isotope ratios: 234U/238U = 9.45 × 10−6 ± 5.0 × 10−8; 235U/238U = 2.38555 × 10−3 ± 4.7 × 10−7; and 236U/238U = 4.314 × 10−5 ± 4.0 × 10−8. SIMS data show 235U/238U is reproducible to within 1% (within analytical uncertainty in a single wafer, at a scale of 25 μm. Multiple studies have demonstrated homogeneity between wafers of NIST 610 and NIST 611, thus the data reported here can be considered representative of NIST 610 as well.

  16. Imaging Spectral Technology Based Detection and Recognition of Boost-Phase Ballistic Target%基于成像光谱技术的主动段弹道目标检测与识别方法

    Institute of Scientific and Technical Information of China (English)

    吴建峰; 黄树彩; 康红霞; 钟宇; 于强; 赵炜

    2015-01-01

    弹道目标检测与识别问题是天基红外预警系统的核心难题之一。针对主动段弹道目标的检测和识别问题,分析了传统的基于空间和时间特征信息的弹道目标检测与识别方法。利用目标辐射空间与光谱的一致性,提出一种基于成像光谱技术的主动段弹道目标检测与识别方法,将空域目标检测和谱域目标识别两个环节进行联合处理。实验证明,该方法应用于复杂背景下低信噪比的红外弱小目标图像序列能得到较理想的结果,算法检测概率高、虚警概率低、具有较强的实时性。%Ballistic target detection and recognition is one of the core difficult problems of Space -Based Infrared System (SBIRS).Aiming at the problem of detection and recognition of boost-phase ballistic target,the traditional methods based on spatial and temporal characteristic information were analyzed,and the disadvantages of the methods were pointed out .According to the consistency of the target radiation in spatial dimension and spectral dimension,an integrated method for ballistic target detection and recognition was put forward based on imaging spectral technology,in which integrated treatment was made for target detection and recognition in spectral domain spectral domain .Experiment results show that this method can obtain good result toward low SNR infrared image sequence under complex background,the algorithm has high detection probability,low false-alarm probability and fine real-time performance .

  17. The Spectral Shift Function and Spectral Flow

    Science.gov (United States)

    Azamov, N. A.; Carey, A. L.; Sukochev, F. A.

    2007-11-01

    At the 1974 International Congress, I. M. Singer proposed that eta invariants and hence spectral flow should be thought of as the integral of a one form. In the intervening years this idea has lead to many interesting developments in the study of both eta invariants and spectral flow. Using ideas of [24] Singer’s proposal was brought to an advanced level in [16] where a very general formula for spectral flow as the integral of a one form was produced in the framework of noncommutative geometry. This formula can be used for computing spectral flow in a general semifinite von Neumann algebra as described and reviewed in [5]. In the present paper we take the analytic approach to spectral flow much further by giving a large family of formulae for spectral flow between a pair of unbounded self-adjoint operators D and D + V with D having compact resolvent belonging to a general semifinite von Neumann algebra {mathcal{N}} and the perturbation V in {mathcal{N}} . In noncommutative geometry terms we remove summability hypotheses. This level of generality is made possible by introducing a new idea from [3]. There it was observed that M. G. Krein’s spectral shift function (in certain restricted cases with V trace class) computes spectral flow. The present paper extends Krein’s theory to the setting of semifinite spectral triples where D has compact resolvent belonging to {mathcal{N}} and V is any bounded self-adjoint operator in {mathcal{N}} . We give a definition of the spectral shift function under these hypotheses and show that it computes spectral flow. This is made possible by the understanding discovered in the present paper of the interplay between spectral shift function theory and the analytic theory of spectral flow. It is this interplay that enables us to take Singer’s idea much further to create a large class of one forms whose integrals calculate spectral flow. These advances depend critically on a new approach to the calculus of functions of non

  18. Spectral control of diode lasers using external waveguide circuits

    NARCIS (Netherlands)

    Oldenbeuving, Ruud

    2013-01-01

    We investigated spectral control of diode lasers using external waveguide circuits. The purpose of this work is to investigate such external control for providing a new class of diode lasers with technologically interesting properties, such as a narrow spectral bandwidth and spectrally tunable

  19. Spectral control of diode lasers using external waveguide circuits

    NARCIS (Netherlands)

    Oldenbeuving, R.M.

    2013-01-01

    We investigated spectral control of diode lasers using external waveguide circuits. The purpose of this work is to investigate such external control for providing a new class of diode lasers with technologically interesting properties, such as a narrow spectral bandwidth and spectrally tunable outpu

  20. How to Access Spectral Line Databases in the IVOA: SLAP Services in VOSpec

    Science.gov (United States)

    Salgado, J.; Osuna, P.; Guainazzi, M.; Barbarisi, I.; Arviset, C.

    2007-10-01

    In an action led by the ESA-VO project and VO-France, the International Virtual Observatory Alliance (IVOA) is defining the access to spectral line data bases, both theoretical and observational. Two standards are in development, the SLAP (Simple Line Access Protocol) document and the Atomic and Molecular Spectral Line Data Model document. The first standard defines uniform access to spectral line data bases while the second specifies a common universal language for information interchange. The SLAP and the already existing SSAP (Simple Spectrum Access Protocol), integrated into the same VO application, are a powerful combination for astronomical spectral studies. Some very well known spectral line data bases have already implemented SLAP services on their servers, e.g., the NIST Atomic Spectra Database (theoretical), LERMA (observational) or the IASD (Infrared Astronomical Spectral Database) (observational). Other projects, such as ALMA (Atacama Large Millimeter Array), are preparing their databases to be as close as possible to the Spectral Line Data Model and are planning to expose their data in SLAP format. We summarize the content of both the SLAP and AM Line Data Model documents and how these SLAP services have been integrated in VOSpec, the VO reference application for spectral access developed by the ESA-VO team.

  1. Technology

    Directory of Open Access Journals (Sweden)

    Xu Jing

    2016-01-01

    Full Text Available The traditional answer card reading method using OMR (Optical Mark Reader, most commonly, OMR special card special use, less versatile, high cost, aiming at the existing problems proposed a method based on pattern recognition of the answer card identification method. Using the method based on Line Segment Detector to detect the tilt of the image, the existence of tilt image rotation correction, and eventually achieve positioning and detection of answers to the answer sheet .Pattern recognition technology for automatic reading, high accuracy, detect faster

  2. 45 CFR 170.210 - Standards for health information technology to protect electronic health information created...

    Science.gov (United States)

    2010-10-01

    ... information—(1) General. Any encryption algorithm identified by the National Institute of Standards and Technology (NIST) as an approved security function in Annex A of the Federal Information Processing Standards... 45 Public Welfare 1 2010-10-01 2010-10-01 false Standards for health information technology...

  3. 2016 NIST (133Xe) and Transfer (131mXe, 133mXe, 135Xe) Calibration Report

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Troy A. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-03-01

    A significantly improved calibration of the High Purity Germanium detectors used by the Idaho National Laboratory Noble Gas Laboratory was performed during the annual NIST calibration. New sample spacers provide reproducible and secure support of samples at distances of 4, 12, 24, 50 and 100 cm. Bean, 15mL and 50mL Schlenk tube geometries were calibrated. Also included in this year’s calibration was a correlation of detector dead-time with sample activity that can be used to predict the schedule of counting the samples at each distance for each geometry. This schedule prediction will help staff members set calendar reminders so that collection of calibration data at each geometry will not be missed. This report also correlates the counting efficiencies between detectors, so that if the counting efficiency on one detector is not known, it can be estimated from the same geometry on another detector.

  4. Distinct contributions of the nisin biosynthesis enzymes NisB and NisC and transporter NisT to prenisin production by Lactococcus lactis

    NARCIS (Netherlands)

    van Saparoea, H. Bart van den Berg; Bakkes, Patrick J.; Moll, Gert N.; Driessen, Arnold J. M.

    2008-01-01

    Several Lactococcus lactis strains produce the lantibiotic nisin. The dedicated enzymes NisB and NisC and the transporter NisT modify and secrete the ribosomally synthesized nisin precursor peptide. NisB can function in the absence of the cyclase NisC, yielding the dehydrated prenisin that lacks the

  5. Annual Performance of a Two-Speed, Dedicated Dehumidification Heat Pump in the NIST Net-Zero Energy Residential Test Facility.

    Science.gov (United States)

    Payne, W Vance

    2016-01-01

    A 2715 ft(2) (252 m(2)), two story, residential home of the style typical of the Gaithersburg, Maryland area was constructed in 2012 to demonstrate technologies for net-zero energy (NZE) homes (or ZEH). The NIST Net-Zero Energy Residential Test Facility (NZERTF) functions as a laboratory to support the development and adoption of cost-effective NZE designs, technologies, construction methods, and building codes. The primary design goal was to meet the comfort and functional needs of the simulated occupants. The first annual test period began on July 1, 2013 and ended June 30, 2014. During the first year of operation, the home's annual energy consumption was 13039 kWh (4.8 kWh ft(-2), 51.7 kWh m(-2)), and the 10.2 kW solar photovoltaic system generated an excess of 484 kWh. During this period the heating and air conditioning of the home was performed by a novel air-source heat pump that utilized a reheat heat exchanger to allow hot compressor discharge gas to reheat the supply air during a dedicated dehumidification mode. During dedicated dehumidification, room temperature air was supplied to the living space until the relative humidity setpoint of 50% was satisfied. The heat pump consumed a total of 6225 kWh (2.3 kWh ft(-2,) 24.7 kWh m(-2)) of electrical energy for cooling, heating, and dehumidification. Annual cooling efficiency was 10.1 Btu W(-1)h(-1) (2.95 W W(-1)), relative to the rated SEER of the heat pump of 15.8 Btu W(-1)h(-1) (4.63 W W(-1)). Annual heating efficiency was 7.10 Btu W(-1)h(-1) (2.09 W W(-1)), compared with the unit's rated HSPF of 9.05 Btu W(-1)h(-1) (2.65 W W(-1)). These field measured efficiency numbers include dedicated dehumidification operation and standby energy use for the year. Annual sensible heat ratio was approximately 70%. Standby energy consumption was 5.2 % and 3.5 % of the total electrical energy used for cooling and heating, respectively.

  6. Compressive Spectral Renormalization Method

    CERN Document Server

    Bayindir, Cihan

    2016-01-01

    In this paper a novel numerical scheme for finding the sparse self-localized states of a nonlinear system of equations with missing spectral data is introduced. As in the Petviashivili's and the spectral renormalization method, the governing equation is transformed into Fourier domain, but the iterations are performed for far fewer number of spectral components (M) than classical versions of the these methods with higher number of spectral components (N). After the converge criteria is achieved for M components, N component signal is reconstructed from M components by using the l1 minimization technique of the compressive sampling. This method can be named as compressive spectral renormalization (CSRM) method. The main advantage of the CSRM is that, it is capable of finding the sparse self-localized states of the evolution equation(s) with many spectral data missing.

  7. 结合光谱图像技术和SAM分类法的甘蓝中杂草识别研究%Research on Identification of Cabbages and Weeds Combining Spectral Imaging Technology and SAM Taxonomy

    Institute of Scientific and Technical Information of China (English)

    祖琴; 张水发; 曹阳; 赵会义; 党长青

    2015-01-01

    Weeds automatic identification is the key technique and also the bottleneck for implementation of variable spraying and precision pesticide.Therefore,accurate,rapid and non-destructive automatic identification of weeds has become a very important research direction for precision agriculture.Hyperspectral imaging system was used to capture the hyperspectral images of cab-bage seedlings and five kinds of weeds such as pigweed,barnyard grass,goosegrass,crabgrass and setaria with the wavelength ranging from 1 000 to 2 500 nm.In ENVI,by utilizing the MNF rotation to implement the noise reduction and de-correlation of hyperspectral data and reduce the band dimensions from 256 to 11,and extracting the region of interest to get the spectral library as standard spectra,finally,using the SAM taxonomy to identify cabbages and weeds,the classification effect was good when the spectral angle threshold was set as 0.1 radians.In HSI Analyzer,after selecting the training pixels to obtain the standard spectrum,the SAM taxonomy was used to distinguish weeds from cabbages.Furthermore,in order to measure the recognition accuracy of weeds quantificationally,the statistical data of the weeds and non-weeds were obtained by comparing the SAM classi-fication image with the best classification effects to the manual classification image.The experimental results demonstrated that, when the parameters were set as 5-point smoothing,0-order derivative and 7-degree spectral angle,the best classification result was acquired and the recognition rate of weeds,non-weeds and overall samples was 80%,97. 3% and 96. 8% respectively.The method that combined the spectral imaging technology and the SAM taxonomy together took full advantage of fusion information of spectrum and image.By applying the spatial classification algorithms to establishing training sets for spectral identification, checking the similarity among spectral vectors in the pixel level,integrating the advantages of spectra and images

  8. The other spectral flow

    CERN Document Server

    Gato-Rivera, Beatriz; Gato-Rivera, Beatriz; Rosado, Jose Ignacio

    1995-01-01

    Recently we showed that the spectral flow acting on the N=2 twisted topological theories gives rise to a topological algebra automorphism. Here we point out that the untwisting of that automorphism leads to a spectral flow on the untwisted N=2 superconformal algebra which is different from the usual one. This "other" spectral flow does not interpolate between the chiral ring and the antichiral ring. In particular, it maps the chiral ring into the chiral ring and the antichiral ring into the antichiral ring. We discuss the similarities and differences between both spectral flows. We also analyze their action on null states.

  9. Network Transfer of Control Data: An Application of the NIST SMART DATA FLOW

    Directory of Open Access Journals (Sweden)

    Vincent Stanford

    2004-12-01

    Full Text Available Pervasive Computing environments range from basic mobile point of sale terminal systems, to rich Smart Spaces with many devices and sensors such as lapel microphones, audio and video sensor arrays and multiple interactive PDA acting as electronic brief cases, providing authentication, and user preference data to the environment. These systems present new challenges in distributed human-computer interfaces such as how to best use sensor streams, distribute interfaces across multiple devices, and dynamic network management as users come an go, and as devices are added or fail. The NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY SMART DATA FLOW system is a low overhead, high bandwidth transport mechanism for standardized multi-modal data streams. It is designed to allow integration of multiple sensors with distributed processing needed for the sense-recognize-respond cycle of multi modal user interfaces. Its core is a server/client architecture, allowing clients to produce or subscribe to data flows, and supporting steps toward scalable processing, distributing the computing requirements among many network connected computers and pervasive devices. This article introduces the communication broker and provides an example of an effective real time sensor fusion to track a speaker with a video camera using data captured from multi-channel microphone array.

  10. Comparison of line width calibration using critical dimension atomic force microscopes between PTB and NIST

    Science.gov (United States)

    Dai, Gaoliang; Hahm, Kai; Bosse, Harald; Dixson, Ronald G.

    2017-06-01

    International comparisons between National Metrology Institutes are important to verify measurement results and the associated uncertainties. In this paper, we report a comparison of the line width calibration of a crystalline silicon line width standard, referred to as IVPS100-PTB standard, between the Physikalisch-Technische Bundesanstalt in Germany and the National Institute of Standards and Technology in the United States. Critical dimension atomic force microscopy was the measurement method used for this comparison. Both institutes applied generally the same but independently developed traceability pathways: the scaling factor of the atomic force microscope (AFM) scanner was calibrated by a set of step height and lateral standards certified by metrological AFMs, while the effective tip width was ultimately traceable to the lattice parameter of silicon via high resolution transmission electron microscopy. Good agreement has been achieved in the comparison: For two groups of line features with nominal critical dimensions (CDs) of 50 nm, 70 nm, 90 nm, 110 nm and 130 nm that were compared, the observed deviations of CD results were between  -1.5 nm and 0.3 nm. The deviations are well within the associated measurement uncertainty.

  11. Network Transfer of Control Data: An Application of the NIST SMART DATA FLOW

    Directory of Open Access Journals (Sweden)

    Vincent Stanford

    2004-12-01

    Full Text Available Pervasive Computing environments range from basic mobile point of sale terminal systems, to rich Smart Spaces with many devices and sensors such as lapel microphones, audio and video sensor arrays and multiple interactive PDA acting as electronic brief cases, providing authentication, and user preference data to the environment. These systems present new challenges in distributed human-computer interfaces such as how to best use sensor streams, distribute interfaces across multiple devices, and dynamic network management as users come an go, and as devices are added or fail. The NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY SMART DATA FLOW system is a low overhead, high bandwidth transport mechanism for standardized multi-modal data streams. It is designed to allow integration of multiple sensors with distributed processing needed for the sense-recognize-respond cycle of multi modal user interfaces. Its core is a server/client architecture, allowing clients to produce or subscribe to data flows, and supporting steps toward scalable processing, distributing the computing requirements among many network connected computers and pervasive devices. This article introduces the communication broker and provides an example of an effective real time sensor fusion to track a speaker with a video camera using data captured from multi-channel microphone array.

  12. Spectral performance of a whole-body research photon counting detector CT: quantitative accuracy in derived image sets

    Science.gov (United States)

    Leng, Shuai; Zhou, Wei; Yu, Zhicong; Halaweish, Ahmed; Krauss, Bernhard; Schmidt, Bernhard; Yu, Lifeng; Kappler, Steffen; McCollough, Cynthia

    2017-09-01

    Photon-counting computed tomography (PCCT) uses a photon counting detector to count individual photons and allocate them to specific energy bins by comparing photon energy to preset thresholds. This enables simultaneous multi-energy CT with a single source and detector. Phantom studies were performed to assess the spectral performance of a research PCCT scanner by assessing the accuracy of derived images sets. Specifically, we assessed the accuracy of iodine quantification in iodine map images and of CT number accuracy in virtual monoenergetic images (VMI). Vials containing iodine with five known concentrations were scanned on the PCCT scanner after being placed in phantoms representing the attenuation of different size patients. For comparison, the same vials and phantoms were also scanned on 2nd and 3rd generation dual-source, dual-energy scanners. After material decomposition, iodine maps were generated, from which iodine concentration was measured for each vial and phantom size and compared with the known concentration. Additionally, VMIs were generated and CT number accuracy was compared to the reference standard, which was calculated based on known iodine concentration and attenuation coefficients at each keV obtained from the U.S. National Institute of Standards and Technology (NIST). Results showed accurate iodine quantification (root mean square error of 0.5 mgI/cc) and accurate CT number of VMIs (percentage error of 8.9%) using the PCCT scanner. The overall performance of the PCCT scanner, in terms of iodine quantification and VMI CT number accuracy, was comparable to that of EID-based dual-source, dual-energy scanners.

  13. Manajemen Risiko Keamanan Informasi Menggunakan Framework NIST SP 800-30 Revisi 1 (Studi Kasus: STMIK Sumedang

    Directory of Open Access Journals (Sweden)

    Fathoni Mahardika

    2017-07-01

    Full Text Available STMIK Sumedang merupakan institusi yang sudah terbiasa menggunakan perangkat teknologi, dimana pengawasannya dilakukan oleh suatu divisi tersendiri yaitu bagian UPT LPSI. Namun terdapat permasalahan dalam penggunaan TI yang ada saat ini antara lain : (1 Masih sering terjadinya insiden keamanan informasi yang menyebabkan terganggunya proses bisnis perusahaan, (2 Belum adanya pengawasan dan perencanaan yang tepat dalam pengelolaan keamanan informasi di STMIK Sumedang.Manajemen resiko adalah metode untuk penilaian dan mitigasi resiko terhadap aspek kebutuhan keamanan informasi yang memuat 3 unsur penting yaitu : Confidentiality (kerahasiaan, Integrity (integritas, dan Availability (ketersediaan. Manajemen resiko keamanan informasi yang digunakan mengacu pada NIST SP 800-30 Revisi 1. Standar ini digunakan sebagai acuan dalam melakukan manajemen resiko keamanan informasi, untuk mengantisipasi risiko agar kerugian tidak terjadi terhadap organisasi. Sehingga resiko dapat dikelola ke level yang dapat diterima organisasi. Diharapkan akan mengurangi dampak insiden sistem dan teknologi informasi di institusi perguruan tinggi, melindungi proses bisnis organisasi yang penting dari ancaman keamanan, meminimalisir risiko kerugian serta menghindari kegagalan serius terhadap informasi yang ada di STMIK Sumedang. Setelah dilakukan manajemen risiko maka diperlukan control keamanan sebagai dasar acuan bahwa risiko dilakukan mitigasi, diterima/ditransfer oleh pihak manajemen. Kontrol keamanan dikembangkan dari ISO 27002. Untuk mengetahui sejauh mana keamanan informasi organisasi maka dilakukan maturity keamanan informasi organisasi menggunakan control yang dikembangkan dari ISO 27002. Dari hasil maturity ini menjadi dasar dibuatnya rekomendasi standar kebijakan keamanan informasi di STMIK Sumedang.

  14. Science with CMB spectral distortions

    CERN Document Server

    Chluba, Jens

    2014-01-01

    The measurements of COBE/FIRAS have shown that the CMB spectrum is extremely close to a perfect blackbody. There are, however, a number of processes in the early Universe that should create spectral distortions at a level which is within reach of present day technology. In this talk, I will give a brief overview of recent theoretical and experimental developments, explaining why future measurements of the CMB spectrum will open up an unexplored window to early-universe and particle physics with possible non-standard surprises but also several guaranteed signals awaiting us.

  15. A reload and startup plan for conversion of the NIST research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, D. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-31

    The National Institute of Standards and Technology operates a 20 MW research reactor for neutron-based research. The heavy-water moderated and cooled reactor is fueled with high-enriched uranium (HEU) but a program to convert the reactor to low-enriched uranium (LEU) fuel is underway. Among other requirements, a reload and startup test plan must be submitted to the U.S. Nuclear Regulatory Commission (NRC) for their approval. The NRC provides guidance for what should be in the plan to ensure that the licensee has sufficient information to operate the reactor safely. Hence, a plan has been generated consisting of two parts. The reload portion of the plan specifies the fuel management whereby initially only two LEU fuel elements are in the core for eight fuel cycles. This is repeated until a point when the optimum approach is to place four fresh LEU elements into the reactor each cycle. This final transition is repeated and after eight cycles the reactor is completely fueled with LEU. By only adding two LEU fuel elements initially, the plan allows for the consumption of HEU fuel elements that are expected to be in storage at the time of conversion and provides additional qualification of production LEU fuel under actual operating conditions. Because the reload is to take place over many fuel cycles, startup tests will be done at different stages of the conversion. The tests, to be compared with calculations to show that the reactor will operate as planned, are the measurement of critical shim arm position and shim arm and regulating rod reactivity worths. An acceptance criterion for each test is specified based on technical specifications that relate to safe operation. Additional tests are being considered that have less safety significance but may be of interest to bolster the validation of analysis tools.

  16. Nanotechnology Laboratory Continues Partnership with FDA and National Institute of Standards and Technology | Poster

    Science.gov (United States)

    The NCI-funded Nanotechnology Characterization Laboratory (NCL)—a leader in evaluating promising nanomedicines to fight cancer—recently renewed its collaboration with the U.S. Food and Drug Administration (FDA) and the National Institute of Standards and Technology (NIST) to continue its groundbreaking work on characterizing nanomedicines and moving them toward the clinic. In partnership with NIST and the FDA, NCL has laid a solid, scientific foundation for using the power of nanotechnology to increase the potency and target the delivery

  17. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between...

  18. Spectral geometry of spacetime

    CERN Document Server

    Kopf, T

    2000-01-01

    Spacetime, understood as a globally hyperbolic manifold, may be characterized by spectral data using a 3+1 splitting into space and time, a description of space by spectral triples and by employing causal relationships, as proposed earlier. Here, it is proposed to use the Hadamard condition of quantum field theory as a smoothness principle.

  19. Hydrocarbon Spectral Database

    Science.gov (United States)

    SRD 115 Hydrocarbon Spectral Database (Web, free access)   All of the rotational spectral lines observed and reported in the open literature for 91 hydrocarbon molecules have been tabulated. The isotopic molecular species, assigned quantum numbers, observed frequency, estimated measurement uncertainty and reference are given for each transition reported.

  20. Spectral Geometry and Causality

    CERN Document Server

    Kopf, T

    1996-01-01

    For a physical interpretation of a theory of quantum gravity, it is necessary to recover classical spacetime, at least approximately. However, quantum gravity may eventually provide classical spacetimes by giving spectral data similar to those appearing in noncommutative geometry, rather than by giving directly a spacetime manifold. It is shown that a globally hyperbolic Lorentzian manifold can be given by spectral data. A new phenomenon in the context of spectral geometry is observed: causal relationships. The employment of the causal relationships of spectral data is shown to lead to a highly efficient description of Lorentzian manifolds, indicating the possible usefulness of this approach. Connections to free quantum field theory are discussed for both motivation and physical interpretation. It is conjectured that the necessary spectral data can be generically obtained from an effective field theory having the fundamental structures of generalized quantum mechanics: a decoherence functional and a choice of...

  1. Technology Outlook for International Schools in Asia, 2014. An NMC Horizon Project Regional Report

    Science.gov (United States)

    Johnson, L.; Adams Becker, S.; Cummins, M.; Estrada, V.

    2014-01-01

    This report is a collaborative research effort between the New Media Consortium (NMC), Concordia International School Shanghai, and NIST International School in Bangkok, Thailand, to help inform international school leaders in Asia about significant developments in technologies supporting teaching, learning, and creative inquiry in primary and…

  2. 78 FR 34347 - Proposed Information Collection; Comment Request; the Building Construction Technology Extension...

    Science.gov (United States)

    2013-06-07

    ... collection. Sponsored by the National Institute of Standards and Technology (NIST), the Manufacturing...-tuning. Re-tuning is a systematic semi-automated process of identifying operational problems in commercial and industrial buildings. It leverages data collected from the building automation system...

  3. Snapshot spectral imaging system

    Science.gov (United States)

    Arnold, Thomas; De Biasio, Martin; McGunnigle, Gerald; Leitner, Raimund

    2010-02-01

    Spectral imaging is the combination of spectroscopy and imaging. These fields are well developed and are used intensively in many application fields including industry and the life sciences. The classical approach to acquire hyper-spectral data is to sequentially scan a sample in space or wavelength. These acquisition methods are time consuming because only two spatial dimensions, or one spatial and the spectral dimension, can be acquired simultaneously. With a computed tomography imaging spectrometer (CTIS) it is possible to acquire two spatial dimensions and a spectral dimension during a single integration time, without scanning either spatial or spectral dimensions. This makes it possible to acquire dynamic image scenes without spatial registration of the hyperspectral data. This is advantageous compared to tunable filter based systems which need sophisticated image registration techniques. While tunable filters provide full spatial and spectral resolution, for CTIS systems there is always a tradeoff between spatial and spectral resolution as the spatial and spectral information corresponding to an image cube is squeezed onto a 2D image. The presented CTIS system uses a spectral-dispersion element to project the spectral and spatial image information onto a 2D CCD camera array. The system presented in this paper is designed for a microscopy application for the analysis of fixed specimens in pathology and cytogenetics, cell imaging and material analysis. However, the CTIS approach is not limited to microscopy applications, thus it would be possible to implement it in a hand-held device for e.g. real-time, intra-surgery tissue classification.

  4. Stark Broadening Parameters for Neutral Oxygen Spectral Lines

    Indian Academy of Sciences (India)

    N. Alonizan; R. Qindeel; N. Ben Nessib; S. Sahal-Bréchot; Milan S. Dimitrijević

    2015-12-01

    Stark broadening parameters for nine neutral oxygen (O I) lines have been determined within the impact approximation and the semiclassical perturbation method. The atomic data have been taken from the TOPbase and NIST atomic databases. The electron and proton Stark widths and shifts and ion broadening parameter values for these O I lines have been calculated for electron density of 1016 cm$^{−3}$ and for 4 different electron temperatures in the range of 5000 K to 40000 K. These Stark broadening parameters are compared with our previous results (Ben Nessib, N. et al. 1996, Physica Scripta, 54, 603–613), where we calculated Stark broadening parameters for only four O I spectral lines and where Stark widths and shifts were compared with experimental and theoretical data available in the literature. In the present paper, we have also compared our results with the Griem's book (Griem, H. R. 1974, Spectral line broadening by plasmas) and VALD (Ryabchikova, T. et al. 2015, Physica Scripta, 90, 054005) values.

  5. Spectral compression of single photons

    CERN Document Server

    Lavoie, Jonathan; Wright, Logan G; Fedrizzi, Alessandro; Resch, Kevin J

    2013-01-01

    Photons are critical to quantum technologies since they can be used for virtually all quantum information tasks: in quantum metrology, as the information carrier in photonic quantum computation, as a mediator in hybrid systems, and to establish long distance networks. The physical characteristics of photons in these applications differ drastically; spectral bandwidths span 12 orders of magnitude from 50 THz for quantum-optical coherence tomography to 50 Hz for certain quantum memories. Combining these technologies requires coherent interfaces that reversibly map centre frequencies and bandwidths of photons to avoid excessive loss. Here we demonstrate bandwidth compression of single photons by a factor 40 and tunability over a range 70 times that bandwidth via sum-frequency generation with chirped laser pulses. This constitutes a time-to-frequency interface for light capable of converting time-bin to colour entanglement and enables ultrafast timing measurements. It is a step toward arbitrary waveform generatio...

  6. Spectral radius of graphs

    CERN Document Server

    Stevanovic, Dragan

    2015-01-01

    Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the

  7. Unmixing of spectrally similar minerals

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available -bearing oxide/hydroxide/sulfate minerals in complex mixtures be obtained using hyperspectral data? Debba (CSIR) Unmixing of spectrally similar minerals MERAKA 2009 3 / 18 Method of spectral unmixing Old method: problem Linear Spectral Mixture Analysis (LSMA...

  8. Vowel Inherent Spectral Change

    CERN Document Server

    Assmann, Peter

    2013-01-01

    It has been traditional in phonetic research to characterize monophthongs using a set of static formant frequencies, i.e., formant frequencies taken from a single time-point in the vowel or averaged over the time-course of the vowel. However, over the last twenty years a growing body of research has demonstrated that, at least for a number of dialects of North American English, vowels which are traditionally described as monophthongs often have substantial spectral change. Vowel Inherent Spectral Change has been observed in speakers’ productions, and has also been found to have a substantial effect on listeners’ perception. In terms of acoustics, the traditional categorical distinction between monophthongs and diphthongs can be replaced by a gradient description of dynamic spectral patterns. This book includes chapters addressing various aspects of vowel inherent spectral change (VISC), including theoretical and experimental studies of the perceptually relevant aspects of VISC, the relationship between ar...

  9. Temporal Lorentzian spectral triples

    Science.gov (United States)

    Franco, Nicolas

    2014-09-01

    We present the notion of temporal Lorentzian spectral triple which is an extension of the notion of pseudo-Riemannian spectral triple with a way to ensure that the signature of the metric is Lorentzian. A temporal Lorentzian spectral triple corresponds to a specific 3 + 1 decomposition of a possibly noncommutative Lorentzian space. This structure introduces a notion of global time in noncommutative geometry. As an example, we construct a temporal Lorentzian spectral triple over a Moyal-Minkowski spacetime. We show that, when time is commutative, the algebra can be extended to unbounded elements. Using such an extension, it is possible to define a Lorentzian distance formula between pure states with a well-defined noncommutative formulation.

  10. Spectral recognition of graphs

    Directory of Open Access Journals (Sweden)

    Cvetković Dragoš

    2012-01-01

    Full Text Available At some time, in the childhood of spectral graph theory, it was conjectured that non-isomorphic graphs have different spectra, i.e. that graphs are characterized by their spectra. Very quickly this conjecture was refuted and numerous examples and families of non-isomorphic graphs with the same spectrum (cospectral graphs were found. Still some graphs are characterized by their spectra and several mathematical papers are devoted to this topic. In applications to computer sciences, spectral graph theory is considered as very strong. The benefit of using graph spectra in treating graphs is that eigenvalues and eigenvectors of several graph matrices can be quickly computed. Spectral graph parameters contain a lot of information on the graph structure (both global and local including some information on graph parameters that, in general, are computed by exponential algorithms. Moreover, in some applications in data mining, graph spectra are used to encode graphs themselves. The Euclidean distance between the eigenvalue sequences of two graphs on the same number of vertices is called the spectral distance of graphs. Some other spectral distances (also based on various graph matrices have been considered as well. Two graphs are considered as similar if their spectral distance is small. If two graphs are at zero distance, they are cospectral. In this sense, cospectral graphs are similar. Other spectrally based measures of similarity between networks (not necessarily having the same number of vertices have been used in Internet topology analysis, and in other areas. The notion of spectral distance enables the design of various meta-heuristic (e.g., tabu search, variable neighbourhood search algorithms for constructing graphs with a given spectrum (spectral graph reconstruction. Several spectrally based pattern recognition problems appear in many areas (e.g., image segmentation in computer vision, alignment of protein-protein interaction networks in bio

  11. Feasibility study of a novel miniaturized spectral imaging system architecture in UAV surveillance

    Science.gov (United States)

    Liu, Shuyang; Zhou, Tao; Jia, Xiaodong; Cui, Hushan; Huang, Chengjun

    2016-01-01

    The spectral imaging technology is able to analysis the spectral and spatial geometric character of the target at the same time. To break through the limitation brought by the size, weight and cost of the traditional spectral imaging instrument, a miniaturized novel spectral imaging based on CMOS processing has been introduced in the market. This technology has enabled the possibility of applying spectral imaging in the UAV platform. In this paper, the relevant technology and the related possible applications have been presented to implement a quick, flexible and more detailed remote sensing system.

  12. Rapid spectral analysis for spectral imaging.

    Science.gov (United States)

    Jacques, Steven L; Samatham, Ravikant; Choudhury, Niloy

    2010-07-15

    Spectral imaging requires rapid analysis of spectra associated with each pixel. A rapid algorithm has been developed that uses iterative matrix inversions to solve for the absorption spectra of a tissue using a lookup table for photon pathlength based on numerical simulations. The algorithm uses tissue water content as an internal standard to specify the strength of optical scattering. An experimental example is presented on the spectroscopy of portwine stain lesions. When implemented in MATLAB, the method is ~100-fold faster than using fminsearch().

  13. Rapid Classification of Common Plastics Based on Near-Infrared Spectral Technology%基于近红外光谱技术的常见塑料快速分类方法研究

    Institute of Scientific and Technical Information of China (English)

    郭慧玲; 邓文怡; 李晓英

    2012-01-01

    对废弃塑料进行回收再生利用具有重要的意义,首要的问题是对塑料进行鉴别分类。本文主要对塑料快速分类方法做了深入的研究。设计并搭建了采集数据的实验系统,编写了处理数据的处理软件。分别采用了全局相关分析、特征相关分析、欧氏距离和k_means聚类分析对数据进行了处理。对常见PE,PET,PP,PVC等塑料进行快速分类鉴别。其中k_means聚类分析法对89个未知样品的预测结果准确率为92.1%,说明近红外光谱结合k_means聚类法进行常见塑料种类鉴别在技术上是可行的。另外提出采用多模式共识可以进一步提高分类的准确率和可靠性。%Recycling of waste plastics is of great significance and the primary problem is the identification and classification of plastics.An in-depth research on rapid classification of plastics has been made.The experimental system of data collection were designed and set up,the software of data processing was written,then data were processed by using global correlation analysis,characteristics related correlation analysis,Euclidean distance analysis and k_means cluster analysis.The common waste plastics such as PE,PET,PP,and PVC were identified and classified Rapidly.The accuracy rate is 92.1% on the predicted results to 89 unknown samples using k_means cluster analysis method.It is indicated that using the near-infrared spectral technology combined with k_means cluster analysis method to identify common plastic types are technically feasible.In addition,it is proposed that adopting consensus of multi-mode can further improve the classification accuracy and reliability.

  14. 78 FR 67121 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

    Science.gov (United States)

    2013-11-08

    ... and Cyber-Physical Systems Program Office, National Institute of Standards and Technology, 100 Bureau.../committee.cfm . For Further Information Contact: Mr. Cuong Nguyen, Smart Grid and Cyber-Physical Systems....sokol@nist.gov . Committee Information The ISPAB was originally chartered as the Computer System...

  15. Acceptance Factors Influencing Adoption of National Institute of Standards and Technology Information Security Standards: A Quantitative Study

    Science.gov (United States)

    Kiriakou, Charles M.

    2012-01-01

    Adoption of a comprehensive information security governance model and security controls is the best option organizations may have to protect their information assets and comply with regulatory requirements. Understanding acceptance factors of the National Institute of Standards and Technology (NIST) Risk Management Framework (RMF) comprehensive…

  16. Acceptance Factors Influencing Adoption of National Institute of Standards and Technology Information Security Standards: A Quantitative Study

    Science.gov (United States)

    Kiriakou, Charles M.

    2012-01-01

    Adoption of a comprehensive information security governance model and security controls is the best option organizations may have to protect their information assets and comply with regulatory requirements. Understanding acceptance factors of the National Institute of Standards and Technology (NIST) Risk Management Framework (RMF) comprehensive…

  17. Bipolar spectral associative memories.

    Science.gov (United States)

    Spencer, R G

    2001-01-01

    Nonlinear spectral associative memories are proposed as quantized frequency domain formulations of nonlinear, recurrent associative memories in which volatile network attractors are instantiated by attractor waves. In contrast to conventional associative memories, attractors encoded in the frequency domain by convolution may be viewed as volatile online inputs, rather than nonvolatile, off-line parameters. Spectral memories hold several advantages over conventional associative memories, including decoder/attractor separability and linear scalability, which make them especially well suited for digital communications. Bit patterns may be transmitted over a noisy channel in a spectral attractor and recovered at the receiver by recurrent, spectral decoding. Massive nonlocal connectivity is realized virtually, maintaining high symbol-to-bit ratios while scaling linearly with pattern dimension. For n-bit patterns, autoassociative memories achieve the highest noise immunity, whereas heteroassociative memories offer the added flexibility of achieving various code rates, or degrees of extrinsic redundancy. Due to linear scalability, high noise immunity and use of conventional building blocks, spectral associative memories hold much promise for achieving robust communication systems. Simulations are provided showing bit error rates for various degrees of decoding time, computational oversampling, and signal-to-noise ratio.

  18. Noncomputable Spectral Sets

    CERN Document Server

    Teutsch, J

    2007-01-01

    It is possible to enumerate all computer programs. In particular, for every partial computable function, there is a shortest program which computes that function. f-MIN is the set of indices for shortest programs. In 1972, Meyer showed that f-MIN is Turing equivalent to 0'', the halting set with halting set oracle. This paper generalizes the notion of shortest programs, and we use various measures from computability theory to describe the complexity of the resulting "spectral sets." We show that under certain Godel numberings, the spectral sets are exactly the canonical sets 0', 0'', 0''', ... up to Turing equivalence. This is probably not true in general, however we show that spectral sets always contain some useful information. We show that immunity, or "thinness" is a useful characteristic for distinguishing between spectral sets. In the final chapter, we construct a set which neither contains nor is disjoint from any infinite arithmetic set, yet it is 0-majorized and contains a natural spectral set. Thus ...

  19. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  20. Spectral Networks and Snakes

    CERN Document Server

    Gaiotto, Davide; Neitzke, Andrew

    2012-01-01

    We apply and illustrate the techniques of spectral networks in a large collection of A_{K-1} theories of class S, which we call "lifted A_1 theories." Our construction makes contact with Fock and Goncharov's work on higher Teichmuller theory. In particular we show that the Darboux coordinates on moduli spaces of flat connections which come from certain special spectral networks coincide with the Fock-Goncharov coordinates. We show, moreover, how these techniques can be used to study the BPS spectra of lifted A_1 theories. In particular, we determine the spectrum generators for all the lifts of a simple superconformal field theory.

  1. Spectral library searching in proteomics.

    Science.gov (United States)

    Griss, Johannes

    2016-03-01

    Spectral library searching has become a mature method to identify tandem mass spectra in proteomics data analysis. This review provides a comprehensive overview of available spectral library search engines and highlights their distinct features. Additionally, resources providing spectral libraries are summarized and tools presented that extend experimental spectral libraries by simulating spectra. Finally, spectrum clustering algorithms are discussed that utilize the same spectrum-to-spectrum matching algorithms as spectral library search engines and allow novel methods to analyse proteomics data.

  2. Calibrating image plate sensitivity in the 700 to 5000 eV spectral energy range

    Science.gov (United States)

    Haugh, Michael J.; Lee, Joshua; Romano, Edward; Schneider, Marilyn

    2013-09-01

    sensitivity in the spectral range from 700 to 8000 eV. The sensitivity in this spectral range had not previously been measured and was needed for the NIF application. A calibration at the low energy range was done using a diode source and a band pass filter. X-ray beam is filtered and limited by the applied voltage to provide a spectral band that is about 1/10 of the average spectral energy. The X-ray flux is measured using a photodiode that is traceable to National Institute for Standards and Technology (NIST). The spectrum for each X-ray band is measured using a silicon drifted detector. The photodiode calibration method is described. Measurements were made on SR, TR, and specially coated TR image plates. The measurement results will be presented and the uncertainties in the measurement will be discussed. The results will be compared to other measurements and estimation methods.

  3. Blue spectral inflation

    CERN Document Server

    Schunck, Franz E

    2008-01-01

    We reconsider the nonlinear second order Abel equation of Stewart and Lyth, which follows from a nonlinear second order slow-roll approximation. We find a new eigenvalue spectrum in the blue regime. Some of the discrete values of the spectral index n_s have consistent fits to the cumulative COBE data as well as to recent ground-base CMB experiments.

  4. Large Spectral Library Problem

    Energy Technology Data Exchange (ETDEWEB)

    Chilton, Lawrence K.; Walsh, Stephen J.

    2008-10-03

    Hyperspectral imaging produces a spectrum or vector at each image pixel. These spectra can be used to identify materials present in the image. In some cases, spectral libraries representing atmospheric chemicals or ground materials are available. The challenge is to determine if any of the library chemicals or materials exist in the hyperspectral image. The number of spectra in these libraries can be very large, far exceeding the number of spectral channels collected in the ¯eld. Suppose an image pixel contains a mixture of p spectra from the library. Is it possible to uniquely identify these p spectra? We address this question in this paper and refer to it as the Large Spectral Library (LSL) problem. We show how to determine if unique identi¯cation is possible for any given library. We also show that if p is small compared to the number of spectral channels, it is very likely that unique identi¯cation is possible. We show that unique identi¯cation becomes less likely as p increases.

  5. Quarkonium Spectral Functions

    Energy Technology Data Exchange (ETDEWEB)

    Mocsy, Agnes [Department of Mathematics and Science, Pratt Institute, Brooklyn, NY 11205 (United States)

    2009-11-01

    In this talk I summarize the progress achieved in recent years on the understanding of quarkonium properties at finite temperature. Theoretical studies from potential models, lattice QCD, and effective field theories are discussed. I also highlight a bridge from spectral functions to experiment.

  6. Spectral representation of fingerprints

    NARCIS (Netherlands)

    Xu, Haiyun; Bazen, Asker M.; Veldhuis, Raymond N.J.; Kevenaar, Tom A.M.; Akkermans, Anton H.M.

    2007-01-01

    Most fingerprint recognition systems are based on the use of a minutiae set, which is an unordered collection of minutiae locations and directions suffering from various deformations such as translation, rotation and scaling. The spectral minutiae representation introduced in this paper is a novel m

  7. SPAM- SPECTRAL ANALYSIS MANAGER (UNIX VERSION)

    Science.gov (United States)

    Solomon, J. E.

    1994-01-01

    The Spectral Analysis Manager (SPAM) was developed to allow easy qualitative analysis of multi-dimensional imaging spectrometer data. Imaging spectrometers provide sufficient spectral sampling to define unique spectral signatures on a per pixel basis. Thus direct material identification becomes possible for geologic studies. SPAM provides a variety of capabilities for carrying out interactive analysis of the massive and complex datasets associated with multispectral remote sensing observations. In addition to normal image processing functions, SPAM provides multiple levels of on-line help, a flexible command interpretation, graceful error recovery, and a program structure which can be implemented in a variety of environments. SPAM was designed to be visually oriented and user friendly with the liberal employment of graphics for rapid and efficient exploratory analysis of imaging spectrometry data. SPAM provides functions to enable arithmetic manipulations of the data, such as normalization, linear mixing, band ratio discrimination, and low-pass filtering. SPAM can be used to examine the spectra of an individual pixel or the average spectra over a number of pixels. SPAM also supports image segmentation, fast spectral signature matching, spectral library usage, mixture analysis, and feature extraction. High speed spectral signature matching is performed by using a binary spectral encoding algorithm to separate and identify mineral components present in the scene. The same binary encoding allows automatic spectral clustering. Spectral data may be entered from a digitizing tablet, stored in a user library, compared to the master library containing mineral standards, and then displayed as a timesequence spectral movie. The output plots, histograms, and stretched histograms produced by SPAM can be sent to a lineprinter, stored as separate RGB disk files, or sent to a Quick Color Recorder. SPAM is written in C for interactive execution and is available for two different

  8. Evaluation of lead isotope compositions of NIST NBS 981 measured by thermal ionization mass spectrometer and multiple-collector inductively coupled plasma mass spectrometer

    Directory of Open Access Journals (Sweden)

    Honglin Yuan

    2016-09-01

    Full Text Available Because Pb isotopes can be used for tracing, they are widely used in many disciplines. The detection and analysis of Pb isotopes of bulk samples are usually conducted using thermal ionization mass spectrometer (TIMS and multiple-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, both of which need external reference materials with known isotopic compositions to correct for the mass discrimination effect produced during analysis. NIST NBS 981 is the most widely used reference material for Pb isotope analysis; however, the isotopic compositions reported by various analytical laboratories, especially those using TIMS, vary from each other. In this study, we statistically evaluated 229 reported TIMS analysis values collected by GeoReM in the last 30 years, 176 reported MC-ICP-MS analysis values, and 938 MC-ICP-MS analysis results from our laboratory in the last five years. After careful investigation, only 40 TIMS results were found to have double or triple spikes. The ratios of the overall weighted averages, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, obtained from 40 spiked TIMS reports and 1114 MC-ICP-MS results of NIST NBS 981 isotopes were 16.9406 ± 0.0003 (2s, 15.4957 ± 0.0002 (2s, and 36.7184 ± 0.0007 (2s, respectively.

  9. Concurrent determination of 237Np and Pu isotopes using ICP-MS: analysis of NIST environmental matrix standard reference materials 4357, 1646a, and 2702.

    Science.gov (United States)

    Matteson, Brent S; Hanson, Susan K; Miller, Jeffrey L; Oldham, Warren J

    2015-04-01

    An optimized method was developed to analyze environmental soil and sediment samples for (237)Np, (239)Pu, and (240)Pu by ICP-MS using a (242)Pu isotope dilution standard. The high yield, short time frame required for analysis, and the commercial availability of the (242)Pu tracer are significant advantages of the method. Control experiments designed to assess method uncertainty, including variation in inter-element fractionation that occurs during the purification protocol, suggest that the overall precision for measurements of (237)Np is typically on the order of ± 5%. Measurements of the (237)Np concentration in a Peruvian Soil blank (NIST SRM 4355) spiked with a known concentration of (237)Np tracer confirmed the accuracy of the method, agreeing well with the expected value. The method has been used to determine neptunium and plutonium concentrations in several environmental matrix standard reference materials available from NIST: SRM 4357 (Radioactivity Standard), SRM 1646a (Estuarine Sediment) and SRM 2702 (Inorganics in Marine Sediment).

  10. Determination of Iron (Fe and Calcium (Ca in NIST SRM 1566b (Oyster tissue using Flame Atomic Absorption Spectrometry (F-AAS by Standard Addition Method

    Directory of Open Access Journals (Sweden)

    Fitri Dara

    2017-03-01

    Full Text Available NIST Standard Reference Material (SRM 1566b was employed for the determination of Iron (Fe andCalcium (Ca as nutrients in food matrix using Flame Atomic Absorption Spectrometry (F-AAS. Thecertified value of SRM 1566b for Fe and Ca are 205.8 ± 6.8 mg/kg and 0.0838 ± 0.0020 (% or 838 ±20 mg/kg, respectively. This certified values are based on results obtained by single primary method(Isotope Dilution Inductively Couple Plasma Mass Spectrometry at NIST with confirmation by othermethods at National Metrology Institute of P.R. China. This paper proposed a method fordetermination of Fe and Ca in food matrix as recommended by AOAC official with a littlemodification. The method was commenced from the destruction of all organic matter by dry oxidationbefore analysis by standard addition. Under optimum condition, the results of the determination of Feand Ca in SRM 1566b were agreed well with the certificate value. This method would be useful forroutine analysis in food testing laboratories.

  11. Spectral-collocation variational integrators

    Science.gov (United States)

    Li, Yiqun; Wu, Boying; Leok, Melvin

    2017-03-01

    Spectral methods are a popular choice for constructing numerical approximations for smooth problems, as they can achieve geometric rates of convergence and have a relatively small memory footprint. In this paper, we introduce a general framework to convert a spectral-collocation method into a shooting-based variational integrator for Hamiltonian systems. We also compare the proposed spectral-collocation variational integrators to spectral-collocation methods and Galerkin spectral variational integrators in terms of their ability to reproduce accurate trajectories in configuration and phase space, their ability to conserve momentum and energy, as well as the relative computational efficiency of these methods when applied to some classical Hamiltonian systems. In particular, we note that spectrally-accurate variational integrators, such as the Galerkin spectral variational integrators and the spectral-collocation variational integrators, combine the computational efficiency of spectral methods together with the geometric structure-preserving and long-time structural stability properties of symplectic integrators.

  12. Context Dependent Spectral Unmixing

    Science.gov (United States)

    2014-08-01

    International Geoscience and Remote Sensing Symposium (IGARSS), Cape Town, South Africa , July 2009. HONORS AND AWARDS: 1. IEEE Outstanding CECS Student Award...COMMEND on the Usgs1C2M3 data across the 25 runs and at all noise levels: (a) SME , (b) SMAE, (c) AME. . . . . . . . . . . . . . 59 6.10 True (solid lines...identifying multiple sets of endmembers. In other words, the unmixing process is adapted to different regions of the spectral space. Another challenge with most

  13. 比光谱-导数分光光度法在多光谱成像技术上的应用%The application of ratio-spectra derivative spectrophotometry in multi-spectral imaging technology

    Institute of Scientific and Technical Information of China (English)

    徐楠; 单长吉; 李林; 张瑶

    2011-01-01

    针对基于Kubelka—Munk理论光谱反射比重建算法中获得浓度矩阵难的技术环节,提出了一种全新的光谱反射比的重建方法——基于比光谱一导数分光光度法的光谱反射比重建算法,并以获取二元混合颜料样本颜色信息为例,证明了此算法的可行性.%In this paper, in order to solve the difficulty of obtaining concentration matrix in the spectral reflectance re- construction algorithm based on Kubelka-Munk theory, we propose a new spectral reflectance reconstruction method-the spectral reflectance reconstruction algorithm based on ratio-spectra derivative spectrophotometry. By obtaining color in- formation of the dye binary mixture samples prove the feasibility of this algorithm.

  14. 基于最大熵谱估计的回波信号检测技术研究%Research on Echo Signal Detection Technology Based on Maximum Entropy Spectral Estimation

    Institute of Scientific and Technical Information of China (English)

    李红; 雷志勇

    2011-01-01

    提出了最大熵谱估计和LMS自适应算法提取激光测距系统的反射回波信号。研究了最大熵谱估计的信号检测原理,采用Burg算法求取AR模型相关参数,设计LMS自适应滤波器提取回波信号,并分析了Burg最大熵谱估计在激光测距系统回波信号检测中的应用。仿真分析表明,最大熵谱估计和LMS自适应算法相结合可以有效地从背景噪声中提取有用的激光反射回波信号。%Maximum entropy spectral estimation and LMS adaptive algorithm were proposed to extract the reflection echo signal of laser ranging system.The theory of the maximum entropy spectra estimation was researched,the Burg algorithm was used to obtain correlative parameters of model,and LMS filter was designed to extract useful signal from weak echo signal.The applications of Burg maximum entropy spectral estimation were analyzed in echo signal detection of laser ranging system.Simluation results show that the maximum entropy spectral estimation and LMS adaptive algorithm can extract echo signal of laser ranging system effectively from background noises.

  15. CONTRAST ENHANCED SPECTRAL MAMMOGRAPHY (CESM (REVIEW

    Directory of Open Access Journals (Sweden)

    N. I. Rozhkova

    2015-01-01

    Full Text Available The problem of early diagnosis of a breast cancer is extremely actual. Growth of incidence at women from 19 to 39 years increased for 34% over the last 10 years. It defines need of acceleration of development and deployment of the latest technologies of identification of the earliest symptoms of diseases. The x-ray mammography is the conducting method among of all radiological methods of diagnostics. Nevertheless a number of restrictions of method reduces its efficiency. The technologies increasing informational content of x-ray mammography – the leading method of screening – due to use of artificial contrasting and advantages of digital technologies are constantly developed. In this review it is described works, in which the authors having clinical experience of application of CESM – contrastenhanced spectral mammography on representative group of women. Positive sides and restrictions of new technology in comparison with mammography, ultrasonography and MRT are shown in this article.

  16. 基于光谱和成像技术的作物养分生理信息快速检测研究进展%Critical review of fast detection of crop nutrient and physiological information with spectral and imaging technology

    Institute of Scientific and Technical Information of China (English)

    何勇; 彭继宇; 刘飞; 张初; 孔汶汶

    2015-01-01

    The research achievements and growing trends of spectral and imaging technology in fast detection of crop nutrient and physiological information were reviewed. Firstly, the principle of spectral and imaging technology, the data processing methods, modeling methods and the indexes of model evaluation were briefly introduced in this paper. Secondly, this paper focused on the research achievements and applications of spectral and imaging technology in fast detection of crop nutrient and physiological information of five kinds of crops (i.e. rice, wheat, oilseed rape, maize, soybean), including chlorophyll content and nitrogen content detection, crop diseases and pests monitoring, stress diagnosis (water, heavy metal, weed, pesticide stress) and yield prediction. In nutrient content and chlorophyll content detection, the data was acquired by ground-based sensing, aircraft-based sensing and satellite-based sensing, and the raw spectra, as well as vegetable indices, were used to build quantitative models. In crop diseases and pests monitoring, spectral and imaging technology were used to discriminate the crop diseases and pests, and diagnose the crop stress level. As for stress diagnosis, several recently-reported researches were briefly reviewed. In yield prediction, this paper was mainly focused on predicting the canopy parameters which were found to be significantly related to crop yield. Although the ability of spectral and imaging technology was proved, there were several problems needed to be solved. 1) The detection of crop nutrient and physiological information with spectral and imaging technology is affected by crop type, crop growing stage, operational conditions, environmental parameters and field management. Therefore, the stability and reliability of the model needs to be improved, which can be overcome by choosing suitable pretreatment methods and chemometrics methods or proposing new vegetable indices which are insensitive to these influencing factors. 2

  17. [Review of normal spectral emissivity standard reference materials].

    Science.gov (United States)

    Yu, Kun; Liu, Yu-Fang; Zhao, Yue-Jin

    2012-11-01

    In order to improve the accuracy of spectral emissivity measurement, standard reference materials of spectral emissivity as the dissemination of quantity in spectral emissivity measurement are used for the calibration of spectral emissivity measurement apparatus. In the present paper, firstly the standard reference materials data proposed by the American National Institute of Standards and Technology are introduced, and some underlying standard reference materials suggested by some metering departments in Europe are analyzed in detail For the standard reference material Armco iron and SiC proposed by some researchers, the advantages and disadvantages were explored. Finally, the characteristics of standard reference materials are summarized, and the future development of spectral emissivity measurement standard is prospected.

  18. 用高光谱成像技术检测柑橘红蜘蛛为害叶片的色素含量%Pigment content measurement for citrus red mite infected leaf using hyper-spectral imaging technology

    Institute of Scientific and Technical Information of China (English)

    李震; 洪添胜; 倪慧娜; 李楠; 王建; 郑建宝; 林瀚

    2014-01-01

    In order to solve the high workload and low efficiency problems while measuring the pigment content variation of citrus red mite infested leaves using the traditional physical and chemical methods, a novel pigment content measurement method for citrus red mite infested leaf using the hyper-spectral imaging technology was studied in this paper. In the research, 400 healthy leaves and 400 sick leaves were included as the test samples in which 350 healthy leaves and 350 sick leaves were utilized for model establishment and the other 50 leaves of each type were used for a model test. Each leaf’s original spectrum and its first order deviation in its particular healthy and sick area were acquired to investigate the characteristic spectrum bands which could mostly reflect the variation of leaf pigment content. The correlation between characteristic spectrum band ratios and pigment content was analyzed. An univariate linear regression method was applied to analyze the pigment content prediction effect using the common vegetation indexes. A leaf pigment content prediction model was established, using the stepwise regression method, and the model’s prediction ability was tested using the F test. Experimental results indicated that it is not satisfactory using the common vegetation indexes to predict leaf pigment content since they are not specially selected for citrus trees. The selected three characteristic spectrum band ratios of 667/522, 667/647, and 522/647 nm, each of which has a high correlation with a leaf’s three types of pigment content, were applied in the stepwise regression method to establish pigment content prediction models. Two out of three of the characteristic spectrum band ratios of 667/522 and 667/647 nm, which gave the best performance, were used as independent values for model establishment. The F test results indicated that the established models could preferably predict both healthy and sick leaves chlorophyll a, chlorophyll b, and carotenoid

  19. Spectral signatures of chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We present a new way of measuring chirality, via the spectral shift of photonic band gaps in one-dimensional structures. We derive an explicit mapping of the problem of oblique incidence of circularly polarized light on a chiral one-dimensional photonic crystal with negligible index contrast...... to the formally equivalent problem of linearly polarized light incident on-axis on a non-chiral structure with index contrast. We derive analytical expressions for the first-order shifts of the band gaps for negligible index contrast. These are modified to give good approximations to the band gap shifts also...

  20. Spectral Variability of FSRQs

    Indian Academy of Sciences (India)

    Minfeng Gu; Y. L. Ai

    2011-03-01

    The optical variability of 29 flat spectrum radio quasars in SDSS Stripe 82 region are investigated by using DR7 released multi-epoch data. All FSRQs show variations with overall amplitude ranging from 0.24 mag to 3.46 mag in different sources. About half of FSRQs show a bluer-when-brighter trend, which is commonly observed for blazars. However, only one source shows a redder-when-brighter trend, which implies it is rare in FSRQs. In this source, the thermal emission may be responsible for the spectral behaviour.

  1. Spectrally encoded confocal microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tearney, G.J.; Webb, R.H.; Bouma, B.E. [Wellman Laboratories of Photomedicine, Massachusetts General Hospital, 50 Blossom Street, BAR 703, Boston, Massachusetts 02114 (United States)

    1998-08-01

    An endoscope-compatible, submicrometer-resolution scanning confocal microscopy imaging system is presented. This approach, spectrally encoded confocal microscopy (SECM), uses a quasi-monochromatic light source and a transmission diffraction grating to detect the reflectivity simultaneously at multiple points along a transverse line within the sample. Since this method does not require fast spatial scanning within the probe, the equipment can be miniaturized and incorporated into a catheter or endoscope. Confocal images of an electron microscope grid were acquired with SECM to demonstrate the feasibility of this technique. {copyright} {ital 1998} {ital Optical Society of America}

  2. A New Multichannel Spectral Imaging Laser Scanning Confocal Microscope

    Directory of Open Access Journals (Sweden)

    Yunhai Zhang

    2013-01-01

    Full Text Available We have developed a new multichannel spectral imaging laser scanning confocal microscope for effective detection of multiple fluorescent labeling in the research of biological tissues. In this paper, the design and key technologies of the system are introduced. Representative results on confocal imaging, 3-dimensional sectioning imaging, and spectral imaging are demonstrated. The results indicated that the system is applicable to multiple fluorescent labeling in biological experiments.

  3. Color Image Segmentation Method Based on Improved Spectral Clustering Algorithm

    OpenAIRE

    Dong Qin

    2014-01-01

    Contraposing to the features of image data with high sparsity of and the problems on determination of clustering numbers, we try to put forward an color image segmentation algorithm, combined with semi-supervised machine learning technology and spectral graph theory. By the research of related theories and methods of spectral clustering algorithms, we introduce information entropy conception to design a method which can automatically optimize the scale parameter value. So it avoids the unstab...

  4. BASIC THEORY AND APPLICATIONS OF WELDING ARC SPECTRAL INFORMATION

    Institute of Scientific and Technical Information of China (English)

    LI Junyue; XUE Haitao; LI Huan; SONG Yonglun

    2007-01-01

    Welding arc spectral information is a rising welding Information source. In some occasion, it can reflect many physical phenomena of welding process and solve many problems that cannot be done with arc electric information, acoustic information and other arc information. It is of important significance in developing automatic control technique of welding process and other similar process. Many years study work on welding arc spectral information of the anthor are discussed from three aspects of theory, method and application. Basic theory, view and testing methods of welding arc spectral information has been put forward. In application aspects, many applied examples, for example, monitoring of harmful gases in arc (such as hydrogen and nitrogen) with the method of welding arc spectral information; welding arc spectral imaging of thc welding pool which is used in automatic seam tracking; controlling of welding droplet transfer with welding arc spectral information and so on, are introduced. Especially, the successful application in real time controlling of welding droplet transfer in pulsed GMAW is introduced too. These application examples show that the welding arc spectral information has great applied significance and development potentialities. These content will play an important role in applying and spreading welding arc spectral information technology.

  5. Spectrally resolved resonant propulsion of dielectric microspheres

    CERN Document Server

    Li, Yangcheng; Limberopoulos, Nicholaos I; Urbas, Augustine M; Astratov, Vasily N

    2015-01-01

    Use of resonant light forces opens up a unique approach to high-volume sorting of microspherical resonators with much higher uniformity of resonances compared to that in coupled-cavity structures obtained by the best semiconductor technologies. In this work, the spectral response of the propulsion forces exerted on polystyrene microspheres near tapered microfibers is directly observed. The measurements are based on the control of the detuning between the tunable laser and internal resonances in each sphere with accuracy higher than the width of the resonances. The measured spectral shape of the propulsion forces correlates well with the whispering-gallery mode resonances in the microspheres. The existence of a stable radial trap for the microspheres propelled along the taper is demonstrated. The giant force peaks observed for 20-{\\mu}m spheres are found to be in a good agreement with a model calculation demonstrating an efficient use of the light momentum for propelling the microspheres.

  6. Exoplanetary Detection By Multifractal Spectral Analysis

    CERN Document Server

    Agarwal, Sahil; Wettlaufer, John S

    2016-01-01

    Owing to technological advances the number of exoplanets discovered has risen dramatically in the last few years. However, when trying to observe Earth analogs, it is often difficult to test the veracity of detection. We have developed a new approach to the analysis of exoplanetary spectral observations based on temporal multifractality, which identifies time scales that characterize planetary orbital motion around the host star. Without fitting spectral data to stellar models, we show how the planetary signal can be robustly detected from noisy data using noise amplitude as a source of information. For observation of transiting planets, combining this method with simple geometry allows us to relate the time scales obtained to primary transit and secondary exoplanet eclipse of the exoplanets. Making use of data obtained with ground-based and space-based observations we have tested our approach on HD 189733b. Moreover, we have investigated the use of this technique in measuring planetary orbital motion via dop...

  7. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.

    2015-02-06

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon resampling differentiated polynomials into a lower-degree subspace makes differentiation matrices, and operators built from them, rectangular without any row deletions. Then, boundary and interface conditions can be adjoined to yield a square system. The resulting method is both flexible and robust, and avoids ambiguities that arise when applying the classical row deletion method outside of two-point scalar boundary-value problems. The new method is the basis for ordinary differential equation solutions in Chebfun software, and is demonstrated for a variety of boundary-value, eigenvalue and time-dependent problems.

  8. Spectral disentangling with Spectangular

    Science.gov (United States)

    Sablowski, Daniel P.; Weber, Michael

    2017-01-01

    The paper introduces the software Spectangular for spectral disentangling via singular value decomposition with global optimisation of the orbital parameters of the stellar system or radial velocities of the individual observations. We will describe the procedure and the different options implemented in our program. Furthermore, we will demonstrate the performance and the applicability using tests on artificial data. Additionally, we use high-resolution spectra of Capella to demonstrate the performance of our code on real-world data. The novelty of this package is the implemented global optimisation algorithm and the graphical user interface (GUI) for ease of use. We have implemented the code to tackle SB1 and SB2 systems with the option of also dealing with telluric (static) lines. Based in part on data obtained with the STELLA robotic telescope in Tenerife, an AIP facility jointly operated by AIP and IAC.

  9. Spectral Classification Beyond M

    CERN Document Server

    Leggett, S K; Burgasser, A J; Jones, H R A; Marley, M S; Tsuji, T

    2004-01-01

    Significant populations of field L and T dwarfs are now known, and we anticipate the discovery of even cooler dwarfs by Spitzer and ground-based infrared surveys. However, as the number of known L and T dwarfs increases so does the range in their observational properties, and difficulties have arisen in interpreting the observations. Although modellers have made significant advances, the complexity of the very low temperature, high pressure, photospheres means that problems remain such as the treatment of grain condensation as well as incomplete and non-equilibrium molecular chemistry. Also, there are several parameters which control the observed spectral energy distribution - effective temperature, grain sedimentation efficiency, metallicity and gravity - and their effects are not well understood. In this paper, based on a splinter session, we discuss classification schemes for L and T dwarfs, their dependency on wavelength, and the effects of the parameters T_eff, f_sed, [m/H] and log g on optical and infra...

  10. Spectral Animation Compression

    Institute of Scientific and Technical Information of China (English)

    Chao Wang; Yang Liu; Xiaohu Guo; Zichun Zhong; Binh Le; Zhigang Deng

    2015-01-01

    This paper presents a spectral approach to compress dynamic animation consisting of a sequence of homeomor-phic manifold meshes. Our new approach directly compresses the field of deformation gradient defined on the surface mesh, by decomposing it into rigid-body motion (rotation) and non-rigid-body deformation (stretching) through polar decompo-sition. It is known that the rotation group has the algebraic topology of 3D ring, which is different from other operations like stretching. Thus we compress these two groups separately, by using Manifold Harmonics Transform to drop out their high-frequency details. Our experimental result shows that the proposed method achieves a good balance between the reconstruction quality and the compression ratio. We compare our results quantitatively with other existing approaches on animation compression, using standard measurement criteria.

  11. Spectral disentangling with Spectangular

    CERN Document Server

    Sablowski, Daniel P

    2016-01-01

    The paper introduces the software Spectangular for spectral disentangling via singular value decomposition with global optimisation of the orbital parameters of the stellar system or radial velocities of the individual observations. We will describe the procedure and the different options implemented in our program. Furthermore, we will demonstrate the performance and the applicability using tests on artificial data. Additionally, we use high-resolution spectra of Capella to demonstrate the performance of our code on real-world data. The novelty of this package is the implemented global optimisation algorithm and the graphical user interface (GUI) for ease of use. We have implemented the code to tackle SB1 and SB2 systems with the option of also dealing with telluric (static) lines.

  12. Spectral proper orthogonal decomposition

    CERN Document Server

    Sieber, Moritz; Paschereit, Christian Oliver

    2015-01-01

    The identification of coherent structures from experimental or numerical data is an essential task when conducting research in fluid dynamics. This typically involves the construction of an empirical mode base that appropriately captures the dominant flow structures. The most prominent candidates are the energy-ranked proper orthogonal decomposition (POD) and the frequency ranked Fourier decomposition and dynamic mode decomposition (DMD). However, these methods fail when the relevant coherent structures occur at low energies or at multiple frequencies, which is often the case. To overcome the deficit of these "rigid" approaches, we propose a new method termed Spectral Proper Orthogonal Decomposition (SPOD). It is based on classical POD and it can be applied to spatially and temporally resolved data. The new method involves an additional temporal constraint that enables a clear separation of phenomena that occur at multiple frequencies and energies. SPOD allows for a continuous shifting from the energetically ...

  13. SPECTRAL ANALYSIS OF RADIOXENON

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Matthew W.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Hubbard, Charles W.; McIntyre, Justin I.; Schrom, Brian T.

    2008-09-23

    Monitoring changes in atmospheric radioxenon concentrations is a major tool in the detection of an underground nuclear explosion. Ground based systems like the Automated Radioxenon Sampler /Analyzer (ARSA), the Swedish Unattended Noble gas Analyzer (SAUNA) and the Automatic portable radiometer of isotopes Xe (ARIX), can collect and detect several radioxenon isotopes by processing and transferring samples into a high efficiency beta-gamma coincidence detector. The high efficiency beta-gamma coincidence detector makes these systems highly sensitive to the radioxenon isotopes 133Xe, 131mXe, 133mXe and 135Xe. The standard analysis uses regions of interest (ROI) to determine the amount of a particular radioxenon isotope present. The ROI method relies on the peaks of interest falling within energy limits of the ROI. Some potential problems inherent in this method are the reliance on stable detector gains and a fixed resolution for each energy peak. In addition, when a high activity sample is measured there will be more interference among the ROI, in particular within the 133Xe, 133mXe, and 131mXe regions. A solution to some of these problems can be obtained through spectral fitting of the data. Spectral fitting is simply the fitting of the peaks using known functions to determine the number and relative peak positions and widths. By knowing this information it is possible to determine which isotopes are present. Area under each peak can then be used to determine an overall concentration for each isotope. Using the areas of the peaks several key detector characteristics can be determined: efficiency, energy calibration, energy resolution and ratios between interfering isotopes (Radon daughters).

  14. Atomic Spectral Line Broadening Bibliographic Database Physical Reference Data

    CERN Document Server

    Fuhr, J; National Institute of Standards and Technology. Gaithersburg

    This database contains approximately 800 recent references. These papers contain numerical data, general information, comments, and review articles and are part of the collection of the Data Center on Atomic Line Shapes and Shifts at NIST.

  15. Spectral unmixing: estimating partial abundances

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available of spectral unmixing 3 End-member spectra and synthetic mixtures 4 Results 5 Conclusions Debba (CSIR) Spectral Unmixing LQM 2009 2 / 22 Background and Research Question If research could be as easy as eating a chocolate cake . . . Figure: Can you guess... the ingredients for this chocolate cake? Debba (CSIR) Spectral Unmixing LQM 2009 3 / 22 Background and Research Question Ingredients Quantity unsweetened chocolate unsweetened cocoa powder boiling water flour baking powder baking soda salt unsalted...

  16. Natural and artificial spectral edges in exoplanets

    Science.gov (United States)

    Lingam, Manasvi; Loeb, Abraham

    2017-09-01

    Technological civilizations may rely upon large-scale photovoltaic arrays to harness energy from their host star. Photovoltaic materials, such as silicon, possess distinctive spectral features, including an 'artificial edge' that is characteristically shifted in wavelength shortwards of the 'red edge' of vegetation. Future observations of reflected light from exoplanets would be able to detect both natural and artificial edges photometrically, if a significant fraction of the planet's surface is covered by vegetation or photovoltaic arrays, respectively. The stellar energy thus tapped can be utilized for terraforming activities by transferring heat and light from the day side to the night side on tidally locked exoplanets, thereby producing detectable artefacts.

  17. Spectral Analysis of Markov Chains

    OpenAIRE

    2007-01-01

    The paper deals with the problem of a statistical analysis of Markov chains connected with the spectral density. We present the expressions for the function of spectral density. These expressions may be used to estimate the parameter of the Markov chain.

  18. SPECTRAL ANALYSIS OF EXCHANGE RATES

    Directory of Open Access Journals (Sweden)

    ALEŠA LOTRIČ DOLINAR

    2013-06-01

    Full Text Available Using spectral analysis is very common in technical areas but rather unusual in economics and finance, where ARIMA and GARCH modeling are much more in use. To show that spectral analysis can be useful in determining hidden periodic components for high-frequency finance data as well, we use the example of foreign exchange rates

  19. Miniature spectrally selective dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Adams, R.R.; Macconochie, I.O.; Poole, B.D.

    1983-02-08

    The present invention discloses a miniature spectrally selective dosimeter capable of measuring selected bandwidths of radiation exposure on small mobile areas. This is achieved by the combination of photovoltaic detectors, electrochemical integrators (e-cells) and filters in a small compact case which can be easily attached in close proximity to and substantially parallel to the surface being measured. In one embodiment two photovoltaic detectors, two e-cells and three filters are packaged in a small case with attaching means consisting of a safety pin. In another embodiment, two detectors, one e-cell and three filters are packaged in a small case with attaching means consisting of a clip to clip over a side piece of an eye glass frame in a further embodiment, the electro-optic elements a packaged in a wristwatch case with attaching means being a watchband. The filters in all embodiments allow only selected wavelengths of radiation to be detected by the photovoltaic detectors and then integrated by the e-cells.

  20. Applicability of spectral indices on thickness identification of oil slick

    Science.gov (United States)

    Niu, Yanfei; Shen, Yonglin; Chen, Qihao; Liu, Xiuguo

    2016-10-01

    Hyperspectral remote sensing technology has played a vital role in the identification and monitoring of oil spill events, and amount of spectral indices have been developed. In this paper, the applicability of six frequently-used indices is analyzed, and a combination of spectral indices in aids of support vector machine (SVM) algorithm is used to identify the oil slicks and corresponding thickness. The six spectral indices are spectral rotation (SR), spectral absorption depth (HI), band ratio of blue and green (BG), band ratio of BG and shortwave infrared index (BGN), 555nm and 645nm normalized by the blue band index (NB) and spectral slope (ND). The experimental study is conducted in the Gulf of Mexico oil spill zone, with Airborne Visible Infrared Imaging Spectrometer (AVIRIS) hyperspectral imagery captured in May 17, 2010. The results show that SR index is the best in all six indices, which can effectively distinguish the thickness of the oil slick and identify it from seawater; HI index and ND index can obviously distinguish oil slick thickness; BG, BGN and NB are more suitable to identify oil slick from seawater. With the comparison among different kernel functions of SVM, the classify accuracy show that the polynomial and RBF kernel functions have the best effect on the separation of oil slick thickness and the relatively pure seawater. The applicability of spectral indices of oil slick and the method of oil film thickness identification will in aids of oil/gas exploration and oil spill monitoring.

  1. Spectral numbers in Floer theories

    CERN Document Server

    Usher, Michael

    2007-01-01

    The chain complexes underlying Floer homology theories typically carry a real-valued filtration, allowing one to associate to each Floer homology class a spectral number defined as the infimum of the filtration levels of chains representing that class. These spectral numbers have been studied extensively in the case of Hamiltonian Floer homology by Oh, Schwarz, and others. We prove that the spectral number associated to any nonzero Floer homology class is always finite, and that the infimum in the definition of the spectral number is always attained. In the Hamiltonian case, this implies that what is known as the "nondegenerate spectrality" axiom holds on all closed symplectic manifolds. Our proofs are entirely algebraic and rather elementary, and apply to any Floer-type theory (including Novikov homology) satisfying certain standard formal properties provided that one works with coefficients in a Novikov ring whose degree-zero part \\Lambda_0 is a field. The key ingredient is a theorem about linear transforma...

  2. The characteristic analysis of spectral image for cabbage leaves damaged by diamondback moth pests

    Science.gov (United States)

    Lin, Li-bo; Li, Hong-ning; Cao, Peng-fei; Qin, Feng; Yang, Shu-ming; Feng, Jie

    2015-02-01

    Cabbage growth and health diagnosis are important parts for cabbage fine planting, spectral imaging technology with the advantages of obtaining spectrum and space information of the target at the same time, which has become a research hotspot at home and abroad. The experiment measures the reflection spectrum at different stages using liquid crystal tunable filter (LCTF) and monochromatic CMOS camera composed of spectral imaging system for cabbage leaves damaged by diamondback moth pests, and analyzes its feature bands and the change of spectral parameters. The study shows that the feature bands of cabbage leaves damaged by diamondback moth pests have a tendency to blue light direction, the red edge towards blue shift, and red valley raising in spectral characteristic parameters, which have a good indication in diagnosing the extent of cabbage damaged by pests. Therefore, it has a unique advantage of monitoring the cabbage leaves damaged by diamondback moth pests by combinating feature bands and spectral characteristic parameters in spectral imaging technology.

  3. CCN Spectral Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, James G.

    2009-02-27

    Detailed aircraft measurements were made of cloud condensation nuclei (CCN) spectra associated with extensive cloud systems off the central California coast in the July 2005 MASE project. These measurements include the wide supersaturation (S) range (2-0.01%) that is important for these polluted stratus clouds. Concentrations were usually characteristic of continental/anthropogenic air masses. The most notable feature was the consistently higher concentrations above the clouds than below. CCN measurements are so important because they provide a link between atmospheric chemistry and cloud-climate effects, which are the largest climate uncertainty. Extensive comparisons throughout the eleven flights between two CCN spectrometers operated at different but overlapping S ranges displayed the precision and accuracy of these difficult spectral determinations. There are enough channels of resolution in these instruments to provide differential spectra, which produce more rigorous and precise comparisons than traditional cumulative presentations of CCN concentrations. Differential spectra are also more revealing than cumulative spectra. Only one of the eleven flights exhibited typical maritime concentrations. Average below cloud concentrations over the two hours furthest from the coast for the 8 flights with low polluted stratus was 614?233 at 1% S, 149?60 at 0.1% S and 57?33 at 0.04% S cm-3. Immediately above cloud average concentrations were respectively 74%, 55%, and 18% higher. Concentration variability among those 8 flights was a factor of two. Variability within each flight excluding distances close to the coast ranged from 15-56% at 1% S. However, CN and probably CCN concentrations sometimes varied by less than 1% over distances of more than a km. Volatility and size-critical S measurements indicated that the air masses were very polluted throughout MASE. The aerosol above the clouds was more polluted than the below cloud aerosol. These high CCN concentrations from

  4. Processing Technology of Spectrally Selective Absorption Coatings Used for Flat Collector%平板集热器用光谱选择性吸收涂层工艺技术

    Institute of Scientific and Technical Information of China (English)

    孔令刚; 范多旺; 王成兵; 令晓明

    2013-01-01

    介绍了自行研制的国内首条宽幅(1 250 mm)“空到空、卷对卷”结构连续真空镀膜生产线,并在铜(铝)带材上连续沉积钛基选择性吸收涂层.通过反应气体的分压控制,实现多级溅射法制备多层膜系过程中各单层膜厚和组分的精确控制,强化了吸收层间的干涉效应,改善了涂层的光学性能,同时保证了工艺过程的稳定性和可重复性,涂层的吸收率为(95±2)%,发射率为(5±2)%.%Titanium based spectrally selective absorption coatings are continuous production on copper/aluminum strip using the first "air to air,roll to roll" continuous coatings line(1250mm width)in China developed by ourselves.By reactive gas partial pressure control,we realize precise control of single-layer thickness in multistage sputtering process,enhance interference effects between the absorbing coatings,and then improve coating optical properties.Meanwhile,the stability and reproducibility of the process are ensured.High solar absorptance of (95±2)% has been achieved with low thermal emittance of (5±2)%.

  5. spectral-cube: Read and analyze astrophysical spectral data cubes

    Science.gov (United States)

    Robitaille, Thomas; Ginsburg, Adam; Beaumont, Chris; Leroy, Adam; Rosolowsky, Erik

    2016-09-01

    Spectral-cube provides an easy way to read, manipulate, analyze, and write data cubes with two positional dimensions and one spectral dimension, optionally with Stokes parameters. It is a versatile data container for building custom analysis routines. It provides a uniform interface to spectral cubes, robust to the wide range of conventions of axis order, spatial projections, and spectral units that exist in the wild, and allows easy extraction of cube sub-regions using physical coordinates. It has the ability to create, combine, and apply masks to datasets and is designed to work with datasets too large to load into memory, and provide basic summary statistic methods like moments and array aggregates.

  6. Timescale Analysis of Spectral Lags

    Institute of Scientific and Technical Information of China (English)

    Ti-Pei Li; Jin-Lu Qu; Hua Feng; Li-Ming Song; Guo-Qiang Ding; Li Chen

    2004-01-01

    A technique for timescale analysis of spectral lags performed directly in the time domain is developed. Simulation studies are made to compare the time domain technique with the Fourier frequency analysis for spectral time lags. The time domain technique is applied to studying rapid variabilities of X-ray binaries and γ-ray bursts. The results indicate that in comparison with the Fourier analysis the timescale analysis technique is more powerful for the study of spectral lags in rapid variabilities on short time scales and short duration flaring phenomena.

  7. Primary standardization of C-14 by means of CIEMAT/NIST, TDCR and 4πβ-γ methods; Medida absoluta da atividade de {sup 14}C pelos metodos CIEMAT/NIST, TDCR e em sistema de coincidencia 4πβ-γ

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsova, Maria

    2016-07-01

    In this work, the primary standardization of {sup 14}C solution, which emits beta particles of maximum energy 156 keV, was made by means of three different methods: CIEMAT/NIST and TDCR (Triple To Double Coincidence Ratio) methods in liquid scintillation systems and the tracing method, in the 4πβ-γ coincidence system. TRICARB LSC (Liquid Scintillator Counting) system, equipped with two photomultipliers tubes, was used for CIEMAT/NIST method, using a {sup 3}H standard that emits beta particles with maximum energy of 18.7 keV, as efficiency tracing. HIDEX 300SL LSC system, equipped with three photomultipliers tubes, was used for TDCR method. Samples of {sup 14}C and {sup 3}H, for the liquid scintillator system, were prepared using three commercial scintillation cocktails, UltimaGold, Optiphase Hisafe3 and InstaGel-Plus, in order to compare the performance in the measurements. All samples were prepared with 15 mL scintillators, in glass vials with low potassium concentration. Known aliquots of radioactive solution were dropped onto the cocktail scintillators. In order to obtain the quenching parameter curve, a nitro methane carrier solution and 1 mL of distilled water were used. For measurements in the 4πβ-γ system, {sup 60}Co was used as beta gamma emitter. SCS (software coincidence system) was applied and the beta efficiency was changed by using electronic discrimination. The behavior of the extrapolation curve was predicted with code ESQUEMA, using Monte Carlo technique. The {sup 14}C activity obtained by the three methods applied in this work was compared and the results showed to be in agreement, within the experimental uncertainty. (author)

  8. Broadband Advanced Spectral System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NovaSol proposes to develop an advanced hyperspectral imaging system for earth science missions named BRASS (Broadband Advanced Spectral System). BRASS combines...

  9. Matched Spectral Filter Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes the development of an imaging spectrometer for greenhouse gas and volcanic gas imaging based on matched spectral filtering and compressive imaging....

  10. Spectral Methods for Numerical Relativity

    CERN Document Server

    Grandclément, Philippe

    2007-01-01

    Equations arising in General Relativity are usually to complicated to be solved analytically and one has to rely on numerical methods to solve sets of coupled, partial differential, equations. Amongst the possible choices, this paper focuses on a class called spectral methods where, typically, the various functions are expanded onto sets of orthogonal polynomials or functions. A theoretical introduction on spectral expansion is first given and a particular emphasize is put on the fast convergence of the spectral approximation. We present then different approaches to solve partial differential equations, first limiting ourselves to the one-dimensional case, with one or several domains. Generalization to more dimensions is then discussed. In particular, the case of time evolutions is carefully studied and the stability of such evolutions investigated. One then turns to results obtained by various groups in the field of General Relativity by means of spectral methods. First, works which do not involve explicit t...

  11. Substitution dynamical systems spectral analysis

    CERN Document Server

    Queffélec, Martine

    2010-01-01

    This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...

  12. Spectral Theory and Mirror Symmetry

    CERN Document Server

    Marino, Marcos

    2015-01-01

    Recent developments in string theory have revealed a surprising connection between spectral theory and local mirror symmetry: it has been found that the quantization of mirror curves to toric Calabi-Yau threefolds leads to trace class operators, whose spectral properties are conjecturally encoded in the enumerative geometry of the Calabi-Yau. This leads to a new, infinite family of solvable spectral problems: the Fredholm determinants of these operators can be found explicitly in terms of Gromov-Witten invariants and their refinements; their spectrum is encoded in exact quantization conditions, and turns out to be determined by the vanishing of a quantum theta function. Conversely, the spectral theory of these operators provides a non-perturbative definition of topological string theory on toric Calabi-Yau threefolds. In particular, their integral kernels lead to matrix integral representations of the topological string partition function, which explain some number-theoretic properties of the periods. In this...

  13. Frequency up-conversion based single photon, mid-IR spectral imaging with 20% quantum efficiency

    DEFF Research Database (Denmark)

    Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin; Pedersen, Christian

    Spectral imaging of mid-infrared (mid-IR) light is emerging as a promising technology since important chemical compounds display unique and strong mid-IR spectral fingerprints. We demonstrate for detection a novel method including a field deployable imaging system with single photon sensitivity...

  14. Development of tunable Fabry-Perot spectral camera and light source for medical applications

    Science.gov (United States)

    Kaarre, M.; Kivi, S.; Panouillot, P. E.; Saari, H.; Mäkynen, J.; Sorri, I.; Juuti, M.

    2013-05-01

    VTT has developed a fast, tunable Fabry-Perot (FP) filter component and applied it in making small, lightweight spectral cameras and light sources. One application field where this novel technology is now tested is medical field. A demonstrator has been made to test the applicability of FP based spectral filtering in the imaging of retina in visible light wavelength area.

  15. Nanocatalytic resonance scattering spectral analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The resonance scattering spectral technique has been established using the synchronous scanning technique on spectrofluorometry.Because of its advantages of simplicity,rapidity and sensitivity,it has been widely applied to analyses of proteins,nucleic acids and inorganic ions.This paper summarizes the application of immunonanogold and aptamer modified nanogold(AptAu) catalytic resonance scattering spectral technique in combination with the work of our group,citing 53 references.

  16. Spectral Conditions for Positive Maps

    Science.gov (United States)

    Chruściński, Dariusz; Kossakowski, Andrzej

    2009-09-01

    We provide partial classification of positive linear maps in matrix algebras which is based on a family of spectral conditions. This construction generalizes the celebrated Choi example of a map which is positive but not completely positive. It is shown how the spectral conditions enable one to construct linear maps on tensor products of matrix algebras which are positive but only on a convex subset of separable elements. Such maps provide basic tools to study quantum entanglement in multipartite systems.

  17. Prym varieties of spectral covers

    CERN Document Server

    Hausel, Tamás

    2010-01-01

    Given a possibly reducible and non-reduced spectral cover X over a smooth projective complex curve C we determine the group of connected components of the Prym variety Prym(X/C). We also describe the sublocus of characteristics a for which the Prym variety Prym(X_a/C) is connected. These results extend special cases of work of Ng\\^o who considered integral spectral curves.

  18. 基于耦合技术的单色光谱吸收法检测甲烷气体浓度%Based on the Optical fiber coupling technology of spectral absorption method to detect methane gas concentration

    Institute of Scientific and Technical Information of China (English)

    姜建国; 刘盈萱; 王源

    2014-01-01

    In allusion to flammable and explosive safety problems of electronic testing equipment in methane gas concentration and adjustable laser expensive prices, put forward an application of coupling technique of mono-chromatic spectrum tests to detect methane gas concentration. The choice of monochromatic light source is given based on, designed a monochromatic spectrum absorption detection device based on optical fiber coupling technolo-gy. Application of Matlab is proposed for methane gas concentration and two sets of data output voltage linear fit-ting. Through the output voltage to predict methane gas concentration, and exam the error of the predicted values and the real value. The experimental results show that optical fiber coupling technology was applied to monochromatic spectrum absorption method to detect methane gas concentration can be without power in real-time detection of methane gas concentration, error less than 2%.%针对电子检测装置在甲烷气体浓度检测时存在易燃易爆等安全隐患,本文提出了一种基于光纤耦合技术的单色光谱吸收法检测甲烷气体浓度的方案。给出了单色光源的选择依据,设计了基于光纤耦合技术的单色光谱吸收法检测装置,提出了应用Matlab对甲烷气体浓度与输出电压两组数据进行线性拟合。通过输出电压预测出甲烷气体浓度,并检测了预测值与真实值的误差。实验结果表明,将光纤耦合技术应用于单色光谱吸收法检测甲烷气体浓度,可以在无电力介入的情况下对甲烷气体浓度进行实时检测,误差不超过2%。

  19. Spectrally-Tunable Infrared Camera Based on Highly-Sensitive Quantum Well Infrared Photodetectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a SPECTRALLY-TUNABLE INFRARED CAMERA based on quantum well infrared photodetector (QWIP) focal plane array (FPA) technology. This will build on...

  20. Conjugate Etalon Spectral Imager (CESI) & Scanning Etalon Methane Mapper (SEMM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of the CESI focal plane and optics technology will lead to miniaturized hyperspectral and SWIR-band spectral imaging instrumentation compatible with...

  1. Programmable spectral design and the binary supergrating

    Science.gov (United States)

    Levner, Daniel

    Spectral operations such as wavelength selection, power level manipulation, and chromatic dispersion control are key to many processes in optical telecommunication, spectroscopy, and sensing. In their simplest forms, these functions can be performed using a number of successful devices such as the Fraunhofer ("diffraction") grating, Bragg grating, thin-film filter (TFF), and dispersion-compensating fiber (DCF). More complicated manipulations, however, often require either problematic cascades of many simple elements, the use of custom technologies that offer little adjustment, or the implementation of fully programmable devices, which allow for the desired spectral function to be synthesized ab initio. Here, I present the Binary Supergrating (BSG), a novel technology that permits the programmable and near-arbitrary control of optical amplitude and phase using a simple, robust and practical form. This guided-wave form consists of an aperiodic sequence of binary elements; the sequence, determined through the process of BSG synthesis, encodes an optical program that defines device functionality. The ability to derive optical programs that address broad spectral demands is central to the BSG's extensive capabilities. In consequence, I present a powerful approach to synthesis that exploits existing knowledge in the design of "analog" gratings. This approach is based on a two-step process, which first derives an analog diffractive structure using the best available methods and then transforms it into binary form. Accordingly, I discuss the notion of diffractive structure transformation and introduce the principle of key information. I identify such key information and illustrate its application in grating quantizers based on an atypical form of Delta-Sigma modulation. As a digital approach to spectral engineering, the BSG presents many of the same advantages offered by the digital approach to electronic signal processing (DSP) over its analog predecessors. As such, it

  2. Contributed Review: Absolute spectral radiance calibration of fiber-optic shock-temperature pyrometers using a coiled-coil irradiance standard lamp

    Energy Technology Data Exchange (ETDEWEB)

    Fat’yanov, O. V., E-mail: fatyan1@gps.caltech.edu; Asimow, P. D., E-mail: asimow@gps.caltech.edu [Division of Geological and Planetary Sciences 252-21, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We describe an accurate and precise calibration procedure for multichannel optical pyrometers such as the 6-channel, 3-ns temporal resolution instrument used in the Caltech experimental geophysics laboratory. We begin with a review of calibration sources for shock temperatures in the 3000-30 000 K range. High-power, coiled tungsten halogen standards of spectral irradiance appear to be the only practical alternative to NIST-traceable tungsten ribbon lamps, which are no longer available with large enough calibrated area. However, non-uniform radiance complicates the use of such coiled lamps for reliable and reproducible calibration of pyrometers that employ imaging or relay optics. Careful analysis of documented methods of shock pyrometer calibration to coiled irradiance standard lamps shows that only one technique, not directly applicable in our case, is free of major radiometric errors. We provide a detailed description of the modified Caltech pyrometer instrument and a procedure for its absolute spectral radiance calibration, accurate to ±5%. We employ a designated central area of a 0.7× demagnified image of a coiled-coil tungsten halogen lamp filament, cross-calibrated against a NIST-traceable tungsten ribbon lamp. We give the results of the cross-calibration along with descriptions of the optical arrangement, data acquisition, and processing. We describe a procedure to characterize the difference between the static and dynamic response of amplified photodetectors, allowing time-dependent photodiode correction factors for spectral radiance histories from shock experiments. We validate correct operation of the modified Caltech pyrometer with actual shock temperature experiments on single-crystal NaCl and MgO and obtain very good agreement with the literature data for these substances. We conclude with a summary of the most essential requirements for error-free calibration of a fiber-optic shock-temperature pyrometer using a high-power coiled tungsten halogen

  3. Using active flow technology columns for high through-put and efficient analyses: The drive towards ultra-high through-put high-performance liquid chromatography with mass spectral detection.

    Science.gov (United States)

    Kocic, Danijela; Shalliker, R Andrew

    2015-11-20

    The performance of active flow technology chromatography columns in parallel segmented flow mode packed with 5 μm Hypersil GOLD particles was compared to conventional UHPLC columns packed with 1.9 μm Hypersil GOLD particles. While the conventional UHPLC columns produced more theoretical plates at the optimum flow rate, when separations were performed at maximum through-put the larger particle size AFT column out-performed the UHPLC column. When both the AFT column and the UHPLC column were operated such that they yielded the same number of theoretical plates per separation, the separation on the AFT column was twice as fast as that on the UHPLC column, with the same level of sensitivity and at just 70% of the back pressure. Furthermore, as the flow velocity further increased the performance gain on the AFT column compared to the UHPLC column improved. An additional advantage of the AFT column was that the flow stream at the exit of the column was split in the radial cross section of the peak profile. This enables the AFT column to be coupled to a flow limiting detector, such as a mass spectrometer. When operated under high through-put conditions separations as fast as six seconds, using mobile phase flow rates in the order of 5-6 mL/min have been recorded.

  4. Semiconductor Laser Multi-Spectral Sensing and Imaging

    Directory of Open Access Journals (Sweden)

    Han Q. Le

    2010-01-01

    Full Text Available Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO. These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

  5. Isomer distributions of molecular weight 247 and 273 nitro-PAHs in ambient samples, NIST diesel SRM, and from radical-initiated chamber reactions

    Science.gov (United States)

    Zimmermann, Kathryn; Atkinson, Roger; Arey, Janet; Kojima, Yuki; Inazu, Koji

    2012-08-01

    Molecular weight (mw) 247 nitrofluoranthenes and nitropyrenes and mw 273 nitrotriphenylenes (NTPs), nitrobenz[a]anthracenes, and nitrochrysenes were quantified in ambient particles collected in Riverside, CA, Tokyo, Japan, and Mexico City, Mexico. 2-Nitrofluoranthene (2-NFL) was the most abundant nitro-polycyclic aromatic hydrocarbon (nitro-PAH) in Riverside and Mexico City, and the mw 273 nitro-PAHs were observed in lower concentrations. However, in Tokyo concentrations of 1- + 2-NTP were more similar to that of 2-NFL. NIST SRM 1975 diesel extract standard reference material was also analyzed to examine nitro-PAH isomer distributions, and 12-nitrobenz[a]anthracene was identified for the first time. The atmospheric formation pathways of nitro-PAHs were studied from chamber reactions of fluoranthene, pyrene, triphenylene, benz[a]anthracene, and chrysene with OH and NO3 radicals at room temperature and atmospheric pressure, with the PAH concentrations being controlled by their vapor pressures. Sampling media were spiked with deuterated PAH to examine heterogeneous nitration. Comparing specific nitro-PAH ratios in ambient and diesel particles with those from our chamber experiments suggests that the low 2-NFL/NTPs ratios in Tokyo particulate matter are not a result of gas-phase radical-initiated chemistry since both gas-phase OH and NO3 radical-initiated reactions result in high 2-NFL/NTPs ratios. Comparisons of the relative formation of deuterated nitro-PAHs on the sampling media suggest that heterogeneous reactions with N2O5 on ambient particle surfaces also do not explain the nitro-PAH profiles of Tokyo particles. Thus, the source of NTPs in Tokyo remains unidentified.

  6. 基于多光谱成像技术的宫颈脱落细胞DNA定量分析研究%Study of Cervical Exfoliated Cell 's DNA Quantitative Analysis Based on Multi-Spectral Imaging Technology

    Institute of Scientific and Technical Information of China (English)

    吴正; 曾立波; 吴琼水

    2016-01-01

    The conventional cervical cancer screening methods mainly include TBS (the bethesda system ) classification method and cellular DNA quantitative analysis ,however ,by using multiple staining method in one cell slide ,which is staining the cyto-plasm with Papanicolaou reagent and the nucleus with Feulgen reagent ,the study of achieving both two methods in the cervical cancer screening at the same time is still blank .Because the difficulty of this multiple staining method is that the absorbance of the non-DNA material may interfere with the absorbance of DNA ,so that this paper has set up a multi-spectral imaging system , and established an absorbance unmixing model by using multiple linear regression method based on absorbance 's linear superpo-sition character ,and successfully stripped out the absorbance of DNA to run the DNA quantitative analysis ,and achieved the perfect combination of those two kinds of conventional screening method .Through a series of experiment we have proved that between the absorbance of DNA which is calculated by the absorbance unmixxing model and the absorbance of DNA which is measured there is no significant difference in statistics when the test level is 1% ,also the result of actual application has shown that there is no intersection between the confidence interval of the DNA index of the tetraploid cells which are screened by using this paper's analysis method when the confidence level is 99% and the DNA index's judging interval of cancer cells ,so that the accuracy and feasibility of the quantitative DNA analysis with multiple staining method expounded by this paper have been veri-fied ,therefore this analytical method has a broad application prospect and considerable market potential in early diagnosis of cer-vical cancer and other cancers .%常用的宫颈癌筛查方法有 TBS(the bethesda system)分类法和细胞DNA定量分析法两种 ,而同时利用多重染色方法在同一张细胞涂片上对细胞质进行巴氏染

  7. Transitioning DARPA Technology

    Science.gov (United States)

    2001-05-01

    capable of reflecting images in the visible and infrared spectral regions. The technology is being incorporated into the military eBook (MIL eBook ) for...It’s man portable, highly deployable and fits in the trunk of a cruiser. It has been successfully tested by Los Alamos National Lab and New Mexico State

  8. Spectral Estimation of NMR Relaxation

    Science.gov (United States)

    Naugler, David G.; Cushley, Robert J.

    2000-08-01

    In this paper, spectral estimation of NMR relaxation is constructed as an extension of Fourier Transform (FT) theory as it is practiced in NMR or MRI, where multidimensional FT theory is used. nD NMR strives to separate overlapping resonances, so the treatment given here deals primarily with monoexponential decay. In the domain of real error, it is shown how optimal estimation based on prior knowledge can be derived. Assuming small Gaussian error, the estimation variance and bias are derived. Minimum bias and minimum variance are shown to be contradictory experimental design objectives. The analytical continuation of spectral estimation is constructed in an optimal manner. An important property of spectral estimation is that it is phase invariant. Hence, hypercomplex data storage is unnecessary. It is shown that, under reasonable assumptions, spectral estimation is unbiased in the context of complex error and its variance is reduced because the modulus of the whole signal is used. Because of phase invariance, the labor of phasing and any error due to imperfect phase can be avoided. A comparison of spectral estimation with nonlinear least squares (NLS) estimation is made analytically and with numerical examples. Compared to conventional sampling for NLS estimation, spectral estimation would typically provide estimation values of comparable precision in one-quarter to one-tenth of the spectrometer time when S/N is high. When S/N is low, the time saved can be used for signal averaging at the sampled points to give better precision. NLS typically provides one estimate at a time, whereas spectral estimation is inherently parallel. The frequency dimensions of conventional nD FT NMR may be denoted D1, D2, etc. As an extension of nD FT NMR, one can view spectral estimation of NMR relaxation as an extension into the zeroth dimension. In nD NMR, the information content of a spectrum can be extracted as a set of n-tuples (ω1, … ωn), corresponding to the peak maxima

  9. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    Hynek Hermansky

    2011-10-01

    Information is carried in changes of a signal. The paper starts with revisiting Dudley’s concept of the carrier nature of speech. It points to its close connection to modulation spectra of speech and argues against short-term spectral envelopes as dominant carriers of the linguistic information in speech. The history of spectral representations of speech is briefly discussed. Some of the history of gradual infusion of the modulation spectrum concept into Automatic recognition of speech (ASR) comes next, pointing to the relationship of modulation spectrum processing to wellaccepted ASR techniques such as dynamic speech features or RelAtive SpecTrAl (RASTA) filtering. Next, the frequency domain perceptual linear prediction technique for deriving autoregressive models of temporal trajectories of spectral power in individual frequency bands is reviewed. Finally, posterior-based features, which allow for straightforward application of modulation frequency domain information, are described. The paper is tutorial in nature, aims at a historical global overview of attempts for using spectral dynamics in machine recognition of speech, and does not always provide enough detail of the described techniques. However, extensive references to earlier work are provided to compensate for the lack of detail in the paper.

  10. New approach to spectral features modeling

    NARCIS (Netherlands)

    Brug, H. van; Scalia, P.S.

    2012-01-01

    The origin of spectral features, speckle effects, is explained, followed by a discussion on many aspects of spectral features generation. The next part gives an overview of means to limit the amplitude of the spectral features. This paper gives a discussion of all means to reduce the spectral featur

  11. Adaptive hyperspectral imaging with a MEMS-based full-frame programmable spectral filter

    Science.gov (United States)

    Graff, David L.; Love, Steven P.

    2014-05-01

    Rapidly programmable spatial light modulation devices based on MEMS technology have opened an exciting new arena in spectral imaging: rapidly reprogrammable, high spectral resolution, multi-band spectral filters that enable hyperspectral processing directly in the optical hardware of an imaging sensor. Implemented as a multiplexing spectral selector, a digital micro-mirror device (DMD) can independently choose or reject dozens or hundreds of spectral bands and present them simultaneously to an imaging sensor, forming a complete 2D image. The result is a high-speed, highresolution, programmable spectral filter that gives the user complete control over the spectral content of the image formed at the sensor. This technology enables a wide variety of rapidly reprogrammable operational capabilities within the same sensor including broadband, color, false color, multispectral, hyperspectral and target specific, matched filter imaging. Of particular interest is the ability to implement target-specific hyperspectral matched filters directly into the optical train of the sensor, producing an image highlighting a target within a spectrally cluttered scene in real time without further processing. By performing the hyperspectral image processing at the sensor, such a system can operate with high performance, greatly reduced data volume, and at a fraction of the cost of traditional push broom hyperspectral instruments. Examples of color, false color and target-specific matched-filter images recorded with our visible-spectrum prototype will be displayed, and extensions to other spectral regions will be discussed.

  12. Spectral element simulation of ultrafiltration

    DEFF Research Database (Denmark)

    Hansen, M.; Barker, Vincent A.; Hassager, Ole

    1998-01-01

    A spectral element method for simulating stationary 2-D ultrafiltration is presented. The mathematical model is comprised of the Navier-Stokes equations for the velocity field of the fluid and a transport equation for the concentration of the solute. In addition to the presence of the velocity...... vector in the transport equation, the system is coupled by the dependency of the fluid viscosity on the solute concentration and by a concentration-dependent boundary condition for the Navier-Stokes equations at the membrane surface. The spectral element discretization yields a nonlinear algebraic system....... The performance of the spectral element code when applied to several ultrafiltration problems is reported. (C) 1998 Elsevier Science Ltd. All rights reserved....

  13. Spectral Tensor-Train Decomposition

    DEFF Research Database (Denmark)

    Bigoni, Daniele; Engsig-Karup, Allan Peter; Marzouk, Youssef M.

    2016-01-01

    The accurate approximation of high-dimensional functions is an essential task in uncertainty quantification and many other fields. We propose a new function approximation scheme based on a spectral extension of the tensor-train (TT) decomposition. We first define a functional version of the TT.......e., the “cores”) comprising the functional TT decomposition. This result motivates an approximation scheme employing polynomial approximations of the cores. For functions with appropriate regularity, the resulting spectral tensor-train decomposition combines the favorable dimension-scaling of the TT...... decomposition with the spectral convergence rate of polynomial approximations, yielding efficient and accurate surrogates for high-dimensional functions. To construct these decompositions, we use the sampling algorithm \\tt TT-DMRG-cross to obtain the TT decomposition of tensors resulting from suitable...

  14. Optical Spectral Variability of Blazars

    Indian Academy of Sciences (India)

    Haritma Gaur

    2014-09-01

    It is well established that blazars show flux variations in the complete electromagnetic (EM) spectrum on all possible time scales ranging from a few tens of minutes to several years. Here, we report the review of optical flux and spectral variability properties of different classes of blazars on IDV and STV time-scales. Our analysis show HSPs are less variable in optical bands as compared to LSPs. Also, we investigated the spectral slope variability and found that the average spectral slopes of LSPs showed a good agreement with the synchrotron self-Compton loss-dominated model. However, spectra of the HSPs and FSRQs have significant additional emission components. In general, spectra of BL Lacs get flatter when they become brighter, while for FSRQs the opposite trend appears to hold.

  15. Application of spectral computed tomography in diagnosis of liver and gallbladder diseases

    Directory of Open Access Journals (Sweden)

    LI Bolong

    2017-03-01

    Full Text Available Spectral computed tomography (CT is a perfect combination of diamond probe and strong computer processing technology and a technological revolution of traditional CT. This article reviews the application of spectral CT in the diagnosis of liver and gallbladder diseases. It summarizes the application value of monochromatic spectral CT imaging, spectral curve, material separation and quantitation, and effective atomic number in the diagnosis and differentiation of liver and gallbladder diseases and analyze the advantages of energy spectrum in identification of small lesions, low dose, and judgment of homology. It is pointed out that the application of spectral CT can be further explored in the aspects of early identification, differentiation, and prognosis of tumors.

  16. Exoplanetary Detection by Multifractal Spectral Analysis

    Science.gov (United States)

    Agarwal, Sahil; Del Sordo, Fabio; Wettlaufer, John S.

    2017-01-01

    Owing to technological advances, the number of exoplanets discovered has risen dramatically in the last few years. However, when trying to observe Earth analogs, it is often difficult to test the veracity of detection. We have developed a new approach to the analysis of exoplanetary spectral observations based on temporal multifractality, which identifies timescales that characterize planetary orbital motion around the host star and those that arise from stellar features such as spots. Without fitting stellar models to spectral data, we show how the planetary signal can be robustly detected from noisy data using noise amplitude as a source of information. For observation of transiting planets, combining this method with simple geometry allows us to relate the timescales obtained to primary and secondary eclipse of the exoplanets. Making use of data obtained with ground-based and space-based observations we have tested our approach on HD 189733b. Moreover, we have investigated the use of this technique in measuring planetary orbital motion via Doppler shift detection. Finally, we have analyzed synthetic spectra obtained using the SOAP 2.0 tool, which simulates a stellar spectrum and the influence of the presence of a planet or a spot on that spectrum over one orbital period. We have demonstrated that, so long as the signal-to-noise-ratio ≥ 75, our approach reconstructs the planetary orbital period, as well as the rotation period of a spot on the stellar surface.

  17. Sports Video Segmentation using Spectral Clustering

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhao

    2014-07-01

    Full Text Available With the rapid development of the computer and multimedia technology, the video processing technique is applied to the field of sports in order to analyze the sport video. For sports video analysis, how to segment the sports video image has become an important research topic. Nowadays, the algorithms for video image segmentation mainly include neural network, K-means and so on. However, the accuracy and speed of these algorithms for moving objects segmentation are not satisfied, and easily influenced by the irregular movement of the object and illumination, etc. In view of this, this paper proposes an algorithm for object segmentation in sports video image sequence, based on the spectral clustering. This algorithm simultaneously considers the pixel level visual feature and the edge information of the neighboring pixels to make the calculation of similarity is more intuitive and not affected by factors such as image texture. When clustering the image feature, the proposed method: (1 preprocesses video image sequence and extracts the image feature. (2Using weight function to build and calculate the similar matrix between pixels. (2 Extract feature vector. (3 Perform clustering using spectral clustering algorithm to segment the sports video image. The experimental results indicate that the method proposed in this paper has the advantages, such as lower complexity, high computational effectiveness, low computational amount, and so on. It can get better extraction effects on video image

  18. Spectral analysis by correlation; Analyse spectrale par correlation

    Energy Technology Data Exchange (ETDEWEB)

    Fauque, J.M.; Berthier, D.; Max, J.; Bonnet, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    The spectral density of a signal, which represents its power distribution along the frequency axis, is a function which is of great importance, finding many uses in all fields concerned with the processing of the signal (process identification, vibrational analysis, etc...). Amongst all the possible methods for calculating this function, the correlation method (correlation function calculation + Fourier transformation) is the most promising, mainly because of its simplicity and of the results it yields. The study carried out here will lead to the construction of an apparatus which, coupled with a correlator, will constitute a set of equipment for spectral analysis in real time covering the frequency range 0 to 5 MHz. (author) [French] La densite spectrale d'un signal qui represente la repartition de sa puissance sur l'axe des frequences est une fonction de premiere importance, constamment utilisee dans tout ce qui touche le traitement du signal (identification de processus, analyse de vibrations, etc...). Parmi toutes les methodes possibles de calcul de cette fonction, la methode par correlation (calcul de la fonction de correlation + transformation de Fourier) est tres seduisante par sa simplicite et ses performances. L'etude qui est faite ici va deboucher sur la realisation d'un appareil qui, couple a un correlateur, constituera un ensemble d'analyse spectrale en temps reel couvrant la gamme de frequence 0 a 5 MHz. (auteur)

  19. Large-area, wide-angle, spectrally selective plasmonic absorber

    CERN Document Server

    Wu, Chihhui; John, Jeremy; Milder, Andrew; Zollars, Byron; Savoy, Steve; Shvets, Gennady

    2011-01-01

    A simple metamaterial-based wide-angle plasmonic absorber is introduced, fabricated, and experimentally characterized using angle-resolved infrared spectroscopy. The metamaterials are prepared by nano-imprint lithography, an attractive low-cost technology for making large-area samples. The matching of the metamaterial's impedance to that of vacuum is responsible for the observed spectrally selective "perfect" absorption of infrared light. The impedance is theoretically calculated in the single-resonance approximation, and the responsible resonance is identified as a short-range surface plasmon. The spectral position of the absorption peak (which is as high as 95%) is experimentally shown to be controlled by the metamaterial's dimensions. The persistence of "perfect" absorption with variable metamaterial parameters is theoretically explained. The wide-angle nature of the absorber can be utilized for sub-diffraction-scale infrared pixels exhibiting spectrally selective absorption/emissivity.

  20. Multi-spectral camera development

    CSIR Research Space (South Africa)

    Holloway, M

    2012-10-01

    Full Text Available stream_source_info Holloway_2012.pdf.txt stream_content_type text/plain stream_size 6209 Content-Encoding ISO-8859-1 stream_name Holloway_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Multi-Spectral Camera... Development 4th Biennial Conference Presented by Mark Holloway 10 October 2012 Fused image ? Red, Green and Blue Applications of the Multi-Spectral Camera ? CSIR 2012 Slide 2 Green and Blue, Near Infrared (IR) RED Applications of the Multi...

  1. Stingray: Spectral-timing software

    Science.gov (United States)

    Huppenkothen, Daniela; Bachetti, Matteo; Stevens, Abigail L.; Migliari, Simone; Balm, Paul

    2016-08-01

    Stingray is a spectral-timing software package for astrophysical X-ray (and more) data. The package merges existing efforts for a (spectral-)timing package in Python and is composed of a library of time series methods (including power spectra, cross spectra, covariance spectra, and lags); scripts to load FITS data files from different missions; a simulator of light curves and event lists that includes different kinds of variability and more complicated phenomena based on the impulse response of given physical events (e.g. reverberation); and a GUI to ease the learning curve for new users.

  2. DEVELOPMENT AND UTILIZATION OF URBAN SPECTRAL LIBRARY FOR REMOTE SENSING OF URBAN ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Nurul Ezaty Mohd Nasarudin

    2011-01-01

    Full Text Available Hyperspectral technology is useful for urban studies due to its capability in examining detailed spectral characteristics of urban materials. This study aims to develop a spectral library of urban materials and demonstrate its application in remote sensing analysis of an urban environment. Field measurements were conducted by using ASD FieldSpec 3 Spectroradiometer with wavelength range from 350 to 2500 nm. The spectral reflectance curves of urban materials were interpreted and analyzed. A collection of 22 spectral data was compiled into a spectral library. The spectral library was put to practical use by utilizing the reference spectra for WorldView-2 satellite image classification which demonstrates the usability of such infrastructure to facilitatefurther progress of remote sensing applications in Malaysia.

  3. DEVELOPMENT AND UTILIZATION OF URBAN SPECTRAL LIBRARY FOR REMOTE SENSING OF URBAN ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Nurul Ezaty Mohd Nasarudin

    2011-06-01

    Full Text Available Hyperspectral technology is useful for urban studies due to its capability in examining detailed spectral characteristics of urban materials. This study aims to develop a spectral library of urban materials and demonstrate its application in remote sensing analysis of an urban environment. Field measurements were conducted by using ASD FieldSpec 3 Spectroradiometer with wavelength range from 350 to 2500 nm. The spectral reflectance curves of urban materials were interpreted and analyzed. A collection of 22 spectral data was compiled into a spectral library. The spectral library was put to practical use by utilizing the reference spectra for WorldView-2 satellite image classification which demonstrates the usability of such infrastructure to facilitate further progress of remote sensing applications in Malaysia.

  4. Spectral Analysis of Nonstationary Spacecraft Vibration Data

    Science.gov (United States)

    1965-11-01

    the instantaneous power spectral density function for the process (y(t)). This spectral function can take on negative values for certain cases...power spectral density function is not directly measurable in the frequency domain. An experimental estimate for the function can be obtained only by...called the generalized power spectral density function for the process (y(t)) . This spectral description for nonstationary data is of great value for

  5. Primary Frequency Standards at NIST

    Science.gov (United States)

    2001-11-01

    Mode-Locked Laser, ” Physical Review Letters , 82,3568-337 I. J. Reicher, M. Niering, R. Holzwarth, M. Weitz, T. Udem, and T. W. Hansch, 2000, “Phase...Coherent Vacuum- Ultraviolet to Radio Frequency Comparison with a Mode-Locked Laser, ’’ Physical Review Letters , 84,3232-3235. M. Niering, R...Measurement of the Hydrogen IS- 2s Transition Frequency by Phase Coherent Comparison with a Microwave Cesium Fountain Clock,” Physical Review Letters , 84

  6. Communicating the Future: Best Practices for Communication of Science and Technology to the Public

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Gail

    2002-09-30

    To advance the state of the art in science and technology communication to the public a conference was held March 6-8, 2002 at the National Institute of Standards and Technology in Gaithersburg, MD. This report of the conference proceedings includes a summary statement by the conference steering committee, transcripts or other text summarizing the remarks of conference speakers, and abstracts for 48 "best practice" communications programs selected by the steering committee through an open competition and a formal peer review process. Additional information about the 48 best practice programs is available on the archival conference Web site at www.nist.gov/bestpractices.

  7. Spectral range calculation inside the Research Irradiating Facility Army Technology Center using code MCNPX and comparison with the spectra of energy Caesium 137 raised in laboratory; Calculo gama espectral no interior do irradiador de pesquisa do Centro Tecnologico do Exercito utilizando o codigo MCNPX e comparacao com espectros de energia do Cesio 137 levantados em laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Renato G.; Rebello, Wilson F.; Cavaliere, Marcos Paulo; Vellozo, Sergio O.; Moreira Junior, Luis, E-mail: renatoguedes@ime.eb.br, E-mail: rebello@ime.eb.br, E-mail: eng.cavaliere@gmail.com, E-mail: vellozo@cbpf.br, E-mail: luisjrmoreira@hotmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Vital, Helio C., E-mail: vital@ctex.eb.br [Centro Tecnologico do Exercito (CTEX), Barra de Guaratiba, RJ (Brazil); Silva, Ademir X., E-mail: ademir@con.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Using the MCNPX code, the objective was to calculate by means of computer simulation spectroscopy range inside the irradiation chamber upper radiator gamma research irradiating facility Army Technology Center (CTEx). The calculations were performed in the spectral range usual 2 points for research purposes irradiating the energy spectra of gamma rays from the source of Cesium chloride 137. Sought the discretization of the spectrum in 100 channels at points of upper bound of 1cm higher and lower dose rates previously known. It was also conducted in the laboratory lifting the spectrum of Cesium-137 source using NaI scintillator detector and multichannel analyzer. With the source spectrum Cesium-137 contained in the literature and raised in the laboratory, both used as reference for comparison and analysis in terms of probability of emission maximum of 0.661 MeV The spectra were quite consistent in terms of the behavior of the energy distributions with scores. The position of maximum dose rate showed absorption detection almost maximum energy of 0.661 MeV photopeak In the spectrum of the position of minimum dosage rate, it was found that due to the removal of the source point of interest, some loss detection were caused by Compton scattering. (author)

  8. Rayleigh imaging in spectral mammography

    Science.gov (United States)

    Berggren, Karl; Danielsson, Mats; Fredenberg, Erik

    2016-03-01

    Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.

  9. Spectral Methods for Numerical Relativity

    Directory of Open Access Journals (Sweden)

    Grandclément Philippe

    2009-01-01

    Full Text Available Equations arising in general relativity are usually too complicated to be solved analytically and one must rely on numerical methods to solve sets of coupled partial differential equations. Among the possible choices, this paper focuses on a class called spectral methods in which, typically, the various functions are expanded in sets of orthogonal polynomials or functions. First, a theoretical introduction of spectral expansion is given with a particular emphasis on the fast convergence of the spectral approximation. We then present different approaches to solving partial differential equations, first limiting ourselves to the one-dimensional case, with one or more domains. Generalization to more dimensions is then discussed. In particular, the case of time evolutions is carefully studied and the stability of such evolutions investigated. We then present results obtained by various groups in the field of general relativity by means of spectral methods. Work, which does not involve explicit time-evolutions, is discussed, going from rapidly-rotating strange stars to the computation of black-hole–binary initial data. Finally, the evolution of various systems of astrophysical interest are presented, from supernovae core collapse to black-hole–binary mergers.

  10. Polynomial J-spectral factorization

    NARCIS (Netherlands)

    Kwakernaak, Huibert; Sebek, Michael

    1994-01-01

    Several algorithms are presented for the J-spectral factorization of a para-Hermitian polynomial matrix. The four algorithms that are discussed are based on diagonalization, successive factor extraction, interpolation, and the solution of an algebraic Riccati equation, respectively. The paper includ

  11. Asymptotics of thermal spectral functions

    CERN Document Server

    Caron-Huot, S

    2009-01-01

    We use operator product expansion (OPE) techniques to study the spectral functions of currents at finite temperature, in the high-energy time-like region $\\omega\\gg T$. The leading corrections to the spectral function of currents and stress tensors are proportional to $\\sim T^4$ expectation values in general, and the leading corrections $\\sim g^2T^4$ are calculated at weak coupling, up to one undetermined coefficient in the shear viscosity channel. Spectral functions in the asymptotic regime are shown to be infrared safe up to order $g^8T^4$. The convergence of sum rules in the shear and bulk viscosity channels is established in QCD to all orders in perturbation theory, though numerically significant tails $\\sim T^4/(\\log\\omega)^3$ are shown to exist in the bulk viscosity channel and to have an impact on sum rules recently proposed by Kharzeev and Tuchin. We argue that the spectral functions of currents and stress tensors in strongly coupled $\\mathcal{N}=4$ super Yang-Mills do not receive any medium-dependent...

  12. Spectral representation of Gaussian semimartingales

    DEFF Research Database (Denmark)

    Basse-O'Connor, Andreas

    2009-01-01

    The aim of the present paper is to characterize the spectral representation of Gaussian semimartingales. That is, we provide necessary and sufficient conditions on the kernel K for X t =∫ K t (s) dN s to be a semimartingale. Here, N denotes an independently scattered Gaussian random measure...

  13. Spectral problems for operator matrices

    NARCIS (Netherlands)

    Bátkai, A.; Binding, P.; Dijksma, A.; Hryniv, R.; Langer, H.

    2005-01-01

    We study spectral properties of 2 × 2 block operator matrices whose entries are unbounded operators between Banach spaces and with domains consisting of vectors satisfying certain relations between their components. We investigate closability in the product space, essential spectra and generation of

  14. Spectral characteristics analysis of red tide water in mesocosm experiment

    Science.gov (United States)

    Cui, Tingwei; Zhang, Jie; Zhang, Hongliang; Ma, Yi; Gao, Xuemin

    2003-05-01

    Mesocosm ecosystem experiment with seawater enclosed of the red tide was carried out from July to September 2001. We got four species of biology whose quantities of bion are dominant in the red tide. During the whole process from the beginning to their dying out for every specie, in situ spectral measurements were carried out. After data processing, characteristic spectra of red tide of different dominant species are got. Via comparison and analysis of characteristics of different spectra, we find that in the band region between 685 and 735 nanometers, spectral characteristics of red tide is apparently different from that of normal water. Compared to spectra of normal water, spectra of red tide have a strong reflectance peak in the above band region. As to spectra of red tide dominated by different species, the situations of reflectance peaks are also different: the second peak of Mesodinium rubrum spectrum lies between 726~732 nm, which is more than 21nm away from the other dominant species spectra"s Leptocylindrus danicus"s second spectral peak covers 686~694nm; that of Skeletonema costatum lies between 691~693 nm. Chattonella marina"s second spectral peak lies about 703~705 nm. Thus we can try to determine whether red tide has occurred according to its spectral data. In order to monitor the event of red tide and identify the dominant species by the application of the technology of hyperspectral remote sensing, acquiring spectral data of different dominant species of red tide as much as possible becomes a basic work to be achieved for spectral matching, information extraction and so on based on hyperspectral data.

  15. DOD Information Technology Standard Guidance (ITSG) Version 3.1

    Science.gov (United States)

    1997-04-07

    data and metadata and can be applied to them. d. NIST FIPS 183: IDEFO e. NIST FIPS 184: IDEFIX f. Data element standards in the datz dictionary BSA...183: IDEFO e. NIST FIPS 184: IDEFIX f. Data element standards in the data dictionary BSA, above. 3.9.3.3.6 Recommendations. IRDS, FIPS 156, is

  16. SPAM- SPECTRAL ANALYSIS MANAGER (DEC VAX/VMS VERSION)

    Science.gov (United States)

    Solomon, J. E.

    1994-01-01

    The Spectral Analysis Manager (SPAM) was developed to allow easy qualitative analysis of multi-dimensional imaging spectrometer data. Imaging spectrometers provide sufficient spectral sampling to define unique spectral signatures on a per pixel basis. Thus direct material identification becomes possible for geologic studies. SPAM provides a variety of capabilities for carrying out interactive analysis of the massive and complex datasets associated with multispectral remote sensing observations. In addition to normal image processing functions, SPAM provides multiple levels of on-line help, a flexible command interpretation, graceful error recovery, and a program structure which can be implemented in a variety of environments. SPAM was designed to be visually oriented and user friendly with the liberal employment of graphics for rapid and efficient exploratory analysis of imaging spectrometry data. SPAM provides functions to enable arithmetic manipulations of the data, such as normalization, linear mixing, band ratio discrimination, and low-pass filtering. SPAM can be used to examine the spectra of an individual pixel or the average spectra over a number of pixels. SPAM also supports image segmentation, fast spectral signature matching, spectral library usage, mixture analysis, and feature extraction. High speed spectral signature matching is performed by using a binary spectral encoding algorithm to separate and identify mineral components present in the scene. The same binary encoding allows automatic spectral clustering. Spectral data may be entered from a digitizing tablet, stored in a user library, compared to the master library containing mineral standards, and then displayed as a timesequence spectral movie. The output plots, histograms, and stretched histograms produced by SPAM can be sent to a lineprinter, stored as separate RGB disk files, or sent to a Quick Color Recorder. SPAM is written in C for interactive execution and is available for two different

  17. Liquid Scintillation High Resolution Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A.

    2010-08-06

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  18. Spectral computations for bounded operators

    CERN Document Server

    Ahues, Mario; Limaye, Balmohan

    2001-01-01

    Exact eigenvalues, eigenvectors, and principal vectors of operators with infinite dimensional ranges can rarely be found. Therefore, one must approximate such operators by finite rank operators, then solve the original eigenvalue problem approximately. Serving as both an outstanding text for graduate students and as a source of current results for research scientists, Spectral Computations for Bounded Operators addresses the issue of solving eigenvalue problems for operators on infinite dimensional spaces. From a review of classical spectral theory through concrete approximation techniques to finite dimensional situations that can be implemented on a computer, this volume illustrates the marriage of pure and applied mathematics. It contains a variety of recent developments, including a new type of approximation that encompasses a variety of approximation methods but is simple to verify in practice. It also suggests a new stopping criterion for the QR Method and outlines advances in both the iterative refineme...

  19. Spectral diagonal ensemble Kalman filters

    CERN Document Server

    Kasanický, Ivan; Vejmelka, Martin

    2015-01-01

    A new type of ensemble Kalman filter is developed, which is based on replacing the sample covariance in the analysis step by its diagonal in a spectral basis. It is proved that this technique improves the aproximation of the covariance when the covariance itself is diagonal in the spectral basis, as is the case, e.g., for a second-order stationary random field and the Fourier basis. The method is extended by wavelets to the case when the state variables are random fields, which are not spatially homogeneous. Efficient implementations by the fast Fourier transform (FFT) and discrete wavelet transform (DWT) are presented for several types of observations, including high-dimensional data given on a part of the domain, such as radar and satellite images. Computational experiments confirm that the method performs well on the Lorenz 96 problem and the shallow water equations with very small ensembles and over multiple analysis cycles.

  20. Spectral Synthesis of SDSS Galaxies

    CERN Document Server

    Sodre, J; Mateus, A; Stasinska, G; Gomes, J M

    2005-01-01

    We investigate the power of spectral synthesis as a mean to estimate physical properties of galaxies. Spectral synthesis is nothing more than the decomposition of an observed spectrum in terms of a superposition of a base of simple stellar populations of various ages and metallicities (here from Bruzual & Charlot 2003), producing as output the star-formation and chemical histories of a galaxy, its extinction and velocity dispersion. We discuss the reliability of this approach and apply it to a volume limited sample of 50362 galaxies from the SDSS Data Release 2, producing a catalog of stellar population properties. A comparison with recent estimates of both observed and physical properties of these galaxies obtained by other groups shows good qualitative and quantitative agreement, despite substantial differences in the method of analysis. The confidence in the method is further strengthened by several empirical and astrophysically reasonable correlations between synthesis results and independent quantiti...

  1. Spectral Clustering with Imbalanced Data

    OpenAIRE

    Qian, Jing; Saligrama, Venkatesh

    2013-01-01

    Spectral clustering is sensitive to how graphs are constructed from data particularly when proximal and imbalanced clusters are present. We show that Ratio-Cut (RCut) or normalized cut (NCut) objectives are not tailored to imbalanced data since they tend to emphasize cut sizes over cut values. We propose a graph partitioning problem that seeks minimum cut partitions under minimum size constraints on partitions to deal with imbalanced data. Our approach parameterizes a family of graphs, by ada...

  2. Remote application for spectral collection

    Science.gov (United States)

    Cone, Shelli R.; Steele, R. J.; Tzeng, Nigel H.; Firpi, Alexer H.; Rodriguez, Benjamin M.

    2016-05-01

    In the area of collecting field spectral data using a spectrometer, it is common to have the instrument over the material of interest. In certain instances it is beneficial to have the ability to remotely control the spectrometer. While several systems have the ability to use a form of connectivity to capture the measurement it is essential to have the ability to control the settings. Additionally, capturing reference information (metadata) about the setup, system configuration, collection, location, atmospheric conditions, and sample information is necessary for future analysis leading towards material discrimination and identification. This has the potential to lead to cumbersome field collection and a lack of necessary information for post processing and analysis. The method presented in this paper describes a capability to merge all parts of spectral collection from logging reference information to initial analysis as well as importing information into a web-hosted spectral database. This allows the simplification of collecting, processing, analyzing and storing field spectra for future analysis and comparisons. This concept is developed for field collection of thermal data using the Designs and Prototypes (D&P) Hand Portable FT-IR Spectrometer (Model 102). The remote control of the spectrometer is done with a customized Android application allowing the ability to capture reference information, process the collected data from radiance to emissivity using a temperature emissivity separation algorithm and store the data into a custom web-based service. The presented system of systems allows field collected spectra to be used for various applications by spectral analysts in the future.

  3. Chebyshev and Fourier spectral methods

    CERN Document Server

    Boyd, John P

    2001-01-01

    Completely revised text focuses on use of spectral methods to solve boundary value, eigenvalue, and time-dependent problems, but also covers Hermite, Laguerre, rational Chebyshev, sinc, and spherical harmonic functions, as well as cardinal functions, linear eigenvalue problems, matrix-solving methods, coordinate transformations, methods for unbounded intervals, spherical and cylindrical geometry, and much more. 7 Appendices. Glossary. Bibliography. Index. Over 160 text figures.

  4. The JCMT Spectral Legacy Survey

    CERN Document Server

    Plume, R; Helmich, F; Van der Tak, F F S; Roberts, H; Bowey, J; Buckle, J; Butner, H; Caux, E; Ceccarelli, C; Van Dishoeck, E F; Friberg, P; Gibb, A G; Hatchell, J; Hogerheijde, M R; Matthews, H; Millar, T; Mitchell, G; Moore, T J T; Ossenkopf, V; Rawlings, J; Richer, J; Roellig, M; Schilke, P; Spaans, M; Tielens, A G G M; Thompson, M A; Viti, S; Weferling, B; White, G J; Wouterloot, J; Yates, J; Zhu, M; White, Glenn J.

    2006-01-01

    Stars form in the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes which can reveal the dynamics, physics, chemistry and evolution of these regions, but our understanding of the molecular inventory of sources and how this is related to their physical state and evolution is rudimentary and incomplete. The Spectral Legacy Survey (SLS) is one of seven surveys recently approved by the JCMT Board. Starting in 2007, the SLS will produce a spectral imaging survey of the content and distribution of all the molecules detected in the 345 GHz atmospheric window (between 332 GHz and 373 GHz) towards a sample of 5 sources. Our intended targets are: a low mass core (NGC1333 IRAS4), 3 high mass cores spanning a range of star forming environments and evolutionary states (W49, AFGL2591, and IRAS20126), and a PDR (the Orion Bar). The SLS will use the unique spectral imaging capabilities of HARP-B/ACSIS to study the molecular inventory and the physical structure of these objects, w...

  5. On the concept of spectral singularities

    Indian Academy of Sciences (India)

    Gusein Sh Guseinov

    2009-09-01

    In this paper, we discuss the concept of spectral singularities for non-Hermitian Hamiltonians. We exihibit spectral singularities of some well-known concrete Hamiltonians with complex-valued coefficients.

  6. Global and local aspects of spectral actions

    CERN Document Server

    Iochum, Bruno; Vassilevich, Dmitri

    2012-01-01

    The principal object in noncommutatve geometry is the spectral triple consisting of an algebra A, a Hilbert space H, and a Dirac operator D. Field theories are incorporated in this approach by the spectral action principle, that sets the field theory action to Tr f(D^2/\\Lambda^2), where f is a real function such that the trace exists, and \\Lambda is a cutoff scale. In the low-energy (weak-field) limit the spectral action reproduces reasonably well the known physics including the standard model. However, not much is known about the spectral action beyond the low-energy approximation. In this paper, after an extensive introduction to spectral triples and spectral actions, we study various expansions of the spectral actions (exemplified by the heat kernel). We derive the convergence criteria. For a commutative spectral triple, we compute the heat kernel on the torus up the second order in gauge connection and consider limiting cases.

  7. Spectral efficiency analysis of OCDMA systems

    Institute of Scientific and Technical Information of China (English)

    Hui Yan; Kun Qiu; Yun Ling

    2009-01-01

    We discuss several kinds of code schemes and analyze their spectral efficiency, code utilizing efficiency, and the maximal spectral efficiency. Error correction coding is used to increase the spectral efficiency, and it can avoid the spectral decrease with the increase of the length. The extended primer code (EPC) has the highest spectral efficiency in the unipolar code system. The bipolar code system has larger spectral efficiency than unipolar code system, but has lower code utilizing efficiency and the maximal spectral efficiency. From the numerical results, we can see that the spectral efficiency increases by 0.025 (b/s)/Hz when the bit error rate (BER) increases from 10-9 to 10-7.

  8. On the spectral quality of scanner illumination with LEDs

    Science.gov (United States)

    Cui, Chengwu

    2013-01-01

    Document scanner illumination has evolved along with general illumination technologies. LEDs have become more and more popular as the illumination sources for document scanning. LED technologies provide a wide range of choices both in terms of structural design and spectral compositions. In this report, we examine some popular LED technologies used for document scanner. We evaluate the color rendering performance of scanner models with different illumination technologies by examining their rendering of the Macbeth ColorChecker™ in sRGB. We found that more phosphors in phosphor conversion types of white LEDs may not be necessarily advantageous in terms of scanner color rendering performance. Also CIS type of scanner may be sensitive to the peak wavelength shift and can be particularly problematic when the peaks are out of certain range.

  9. An Improved Variational Method for Hyperspectral Image Pansharpening with the Constraint of Spectral Difference Minimization

    Science.gov (United States)

    Huang, Z.; Chen, Q.; Shen, Y.; Chen, Q.; Liu, X.

    2017-09-01

    Variational pansharpening can enhance the spatial resolution of a hyperspectral (HS) image using a high-resolution panchromatic (PAN) image. However, this technology may lead to spectral distortion that obviously affect the accuracy of data analysis. In this article, we propose an improved variational method for HS image pansharpening with the constraint of spectral difference minimization. We extend the energy function of the classic variational pansharpening method by adding a new spectral fidelity term. This fidelity term is designed following the definition of spectral angle mapper, which means that for every pixel, the spectral difference value of any two bands in the HS image is in equal proportion to that of the two corresponding bands in the pansharpened image. Gradient descent method is adopted to find the optimal solution of the modified energy function, and the pansharpened image can be reconstructed. Experimental results demonstrate that the constraint of spectral difference minimization is able to preserve the original spectral information well in HS images, and reduce the spectral distortion effectively. Compared to original variational method, our method performs better in both visual and quantitative evaluation, and achieves a good trade-off between spatial and spectral information.

  10. Calibration with near-continuous spectral measurements

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Rasmussen, Michael; Madsen, Henrik

    2001-01-01

    In chemometrics traditional calibration in case of spectral measurements express a quantity of interest (e.g. a concentration) as a linear combination of the spectral measurements at a number of wavelengths. Often the spectral measurements are performed at a large number of wavelengths and in thi...... by an example in which the octane number of gasoline is related to near infrared spectral measurements. The performance is found to be much better that for the traditional calibration methods....

  11. USGS Spectral Library Version 7

    Science.gov (United States)

    Kokaly, Raymond F.; Clark, Roger N.; Swayze, Gregg A.; Livo, K. Eric; Hoefen, Todd M.; Pearson, Neil C.; Wise, Richard A.; Benzel, William M.; Lowers, Heather A.; Driscoll, Rhonda L.; Klein, Anna J.

    2017-04-10

    We have assembled a library of spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns [μm]). Laboratory samples of specific minerals, plants, chemical compounds, and manmade materials were measured. In many cases, samples were purified, so that unique spectral features of a material can be related to its chemical structure. These spectro-chemical links are important for interpreting remotely sensed data collected in the field or from an aircraft or spacecraft. This library also contains physically constructed as well as mathematically computed mixtures. Four different spectrometer types were used to measure spectra in the library: (1) Beckman™ 5270 covering the spectral range 0.2 to 3 µm, (2) standard, high resolution (hi-res), and high-resolution Next Generation (hi-resNG) models of Analytical Spectral Devices (ASD) field portable spectrometers covering the range from 0.35 to 2.5 µm, (3) Nicolet™ Fourier Transform Infra-Red (FTIR) interferometer spectrometers covering the range from about 1.12 to 216 µm, and (4) the NASA Airborne Visible/Infra-Red Imaging Spectrometer AVIRIS, covering the range 0.37 to 2.5 µm. Measurements of rocks, soils, and natural mixtures of minerals were made in laboratory and field settings. Spectra of plant components and vegetation plots, comprising many plant types and species with varying backgrounds, are also in this library. Measurements by airborne spectrometers are included for forested vegetation plots, in which the trees are too tall for measurement by a field spectrometer. This report describes the instruments used, the organization of materials into chapters, metadata descriptions of spectra and samples, and possible artifacts in the spectral measurements. To facilitate greater application of the spectra, the library has also been convolved to selected spectrometer and imaging spectrometers sampling and

  12. Planck 2013 results. IX. HFI spectral response

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.;

    2013-01-01

    The Planck HFI spectral response was determined through a series of ground based tests conducted with the HFI focal plane in a cryogenic environment prior to launch. The main goal of the spectral transmission tests is to measure the relative spectral response (including the level of out-of-band s...

  13. Spectral averaging techniques for Jacobi matrices

    CERN Document Server

    del Rio, Rafael; Schulz-Baldes, Hermann

    2008-01-01

    Spectral averaging techniques for one-dimensional discrete Schroedinger operators are revisited and extended. In particular, simultaneous averaging over several parameters is discussed. Special focus is put on proving lower bounds on the density of the averaged spectral measures. These Wegner type estimates are used to analyze stability properties for the spectral types of Jacobi matrices under local perturbations.

  14. Extreme ultraviolet spectral irradiance measurements since 1946

    Science.gov (United States)

    Schmidtke, G.

    2015-03-01

    In the physics of the upper atmosphere the solar extreme ultraviolet (EUV) radiation plays a dominant role controlling most of the thermospheric/ionospheric (T/I) processes. Since this part of the solar spectrum is absorbed in the thermosphere, platforms to measure the EUV fluxes became only available with the development of rockets reaching altitude levels exceeding 80 km. With the availability of V2 rockets used in space research, recording of EUV spectra started in 1946 using photographic films. The development of pointing devices to accurately orient the spectrographs toward the sun initiated intense activities in solar-terrestrial research. The application of photoelectric recording technology enabled the scientists placing EUV spectrometers aboard satellites observing qualitatively strong variability of the solar EUV irradiance on short-, medium-, and long-term scales. However, as more measurements were performed more radiometric EUV data diverged due to the inherent degradation of the EUV instruments with time. Also, continuous recording of the EUV energy input to the T/I system was not achieved. It is only at the end of the last century that there was progress made in solving the serious problem of degradation enabling to monitore solar EUV fluxes with sufficient radiometric accuracy. The data sets available allow composing the data available to the first set of EUV data covering a period of 11 years for the first time. Based on the sophisticated instrumentation verified in space, future EUV measurements of the solar spectral irradiance (SSI) are promising accuracy levels of about 5% and less. With added low-cost equipment, real-time measurements will allow providing data needed in ionospheric modeling, e.g., for correcting propagation delays of navigation signals from space to earth. Adding EUV airglow and auroral emission monitoring by airglow cameras, the impact of space weather on the terrestrial T/I system can be studied with a spectral terrestrial

  15. Space Technology Mission Directorate Game Changing Development Program FY2015 Annual Program Review: Advanced Manufacturing Technology

    Science.gov (United States)

    Vickers, John; Fikes, John

    2015-01-01

    The Advance Manufacturing Technology (AMT) Project supports multiple activities within the Administration's National Manufacturing Initiative. A key component of the Initiative is the Advanced Manufacturing National Program Office (AMNPO), which includes participation from all federal agencies involved in U.S. manufacturing. In support of the AMNPO the AMT Project supports building and Growing the National Network for Manufacturing Innovation through a public-private partnership designed to help the industrial community accelerate manufacturing innovation. Integration with other projects/programs and partnerships: STMD (Space Technology Mission Directorate), HEOMD, other Centers; Industry, Academia; OGA's (e.g., DOD, DOE, DOC, USDA, NASA, NSF); Office of Science and Technology Policy, NIST Advanced Manufacturing Program Office; Generate insight within NASA and cross-agency for technology development priorities and investments. Technology Infusion Plan: PC; Potential customer infusion (TDM, HEOMD, SMD, OGA, Industry); Leverage; Collaborate with other Agencies, Industry and Academia; NASA roadmap. Initiatives include: Advanced Near Net Shape Technology Integrally Stiffened Cylinder Process Development (launch vehicles, sounding rockets); Materials Genome; Low Cost Upper Stage-Class Propulsion; Additive Construction with Mobile Emplacement (ACME); National Center for Advanced Manufacturing.

  16. Ultrafast spectral diffusion measurement on nitrogen vacancy centers in nanodiamonds using correlation interferometry

    CERN Document Server

    Wolters, Janik; Schell, Andreas W; Schröder, Tim; Benson, Oliver

    2012-01-01

    Spectral diffusion is the phenomenon of random jumps in the emission wavelength of narrow lines. This phenomenon is a major hurdle for applications of solid state quantum emitters like quantum dots, molecules or diamond defect centers in an integrated quantum optical technology. Here, we provide further insight into the underlying processes of spectral diffusion of the zero phonon line of single nitrogen vacancy centers in nanodiamonds by using a novel method based on photon correlation interferometry. The method works although the spectral diffusion rate is several orders of magnitude higher than the photon detection rate and thereby improves the time resolution of previous experiments with nanodiamonds by six orders of magnitude. We study the dependency of the spectral diffusion rate on the excitation power, temperature, and excitation wavelength under off-resonant excitation. Our results suggest a strategy to increase the number of spectrally indistinguishable photons emitted by diamond nanocrystals.

  17. Hybrid Spectral Micro-CT: System Design, Implementation, and Preliminary Results

    CERN Document Server

    Bennett, James R; Xu, Qiong; Yu, Hengyong; Walsh, Michael; Butler, Anthony; Butler, Phillip; Cao, Guohua; Mohs, Aaron; Wang, Ge

    2014-01-01

    Spectral CT has proven an important development in biomedical imaging, and there have been several publications in the past years demonstrating its merits in pre-clinical and clinical applications. In 2012, Xu et al. reported that near-term implementation of spectral micro-CT could be enhanced by a hybrid architecture: a narrow-beam spectral "interior" imaging chain integrated with a traditional wide-beam "global" imaging chain. This hybrid integration coupled with compressive sensing (CS)-based interior tomography demonstrated promising results for improved contrast resolution, and decreased system cost and radiation dose. The motivation for the current study is implementation and evaluation of the hybrid architecture with a first-of-its-kind hybrid spectral micro-CT system. Preliminary results confirm improvements in both contrast and spatial resolution. This technology is shown to merit further investigation and potential application in future spectral CT scanner design.

  18. Spectral multitude and spectral dynamics reflect changing conjugation length in single molecules of oligophenylenevinylenes

    KAUST Repository

    Kobayashi, Hiroyuki

    2012-01-01

    Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable estimation of the phenylene torsional barriers. © 2012 The Owner Societies.

  19. Sharp Upper and Lower Bounds for the Laplacian Spectral Radius and the Spectral Radius of Graphs

    Institute of Scientific and Technical Information of China (English)

    Ji-ming Guo

    2008-01-01

    In this paper, sharp upper bounds for the Laplacian spectral radius and the spectral radius of graphs are given, respectively. We show that some known bounds can be obtained from our bounds. For a bipartite graph G, we also present sharp lower bounds for the Laplacian spectral radius and the spectral radius,respectively.

  20. Planar-waveguide integrated spectral comparator.

    Science.gov (United States)

    Mossberg, T W; Iazikov, D; Greiner, C

    2004-06-01

    A cost-effective yet robust and versatile dual-channel spectral comparator is presented. The silica-on-silicon planar-waveguide integrated device includes two holographic Bragg-grating reflectors (HBRs) with complementary spectral transfer functions. Output comprises projections of input signal spectra onto the complementary spectral channels. Spectral comparators may be useful in optical code-division multiplexing, optical packet decoding, spectral target recognition, and the identification of molecular spectra. HBRs may be considered to be mode-specific photonic crystals.

  1. Spectral clustering for TRUS images

    Directory of Open Access Journals (Sweden)

    Salama Magdy MA

    2007-03-01

    Full Text Available Abstract Background Identifying the location and the volume of the prostate is important for ultrasound-guided prostate brachytherapy. Prostate volume is also important for prostate cancer diagnosis. Manual outlining of the prostate border is able to determine the prostate volume accurately, however, it is time consuming and tedious. Therefore, a number of investigations have been devoted to designing algorithms that are suitable for segmenting the prostate boundary in ultrasound images. The most popular method is the deformable model (snakes, a method that involves designing an energy function and then optimizing this function. The snakes algorithm usually requires either an initial contour or some points on the prostate boundary to be estimated close enough to the original boundary which is considered a drawback to this powerful method. Methods The proposed spectral clustering segmentation algorithm is built on a totally different foundation that doesn't involve any function design or optimization. It also doesn't need any contour or any points on the boundary to be estimated. The proposed algorithm depends mainly on graph theory techniques. Results Spectral clustering is used in this paper for both prostate gland segmentation from the background and internal gland segmentation. The obtained segmented images were compared to the expert radiologist segmented images. The proposed algorithm obtained excellent gland segmentation results with 93% average overlap areas. It is also able to internally segment the gland where the segmentation showed consistency with the cancerous regions identified by the expert radiologist. Conclusion The proposed spectral clustering segmentation algorithm obtained fast excellent estimates that can give rough prostate volume and location as well as internal gland segmentation without any user interaction.

  2. Spectral properties of iodine cells for laser standards

    Science.gov (United States)

    Hrabina, Jan; Šarbort, Martin; Acef, Ouali; Du Burck, Frédéric; Chiodo, Nicola; Chea, Erick; Holá, Miroslava; Číp, Ondřej; Lazar, Josef

    2014-12-01

    The main aim of this work is oriented towards preparation and spectral properties evaluation of optical frequency references for laser standards - molecular iodine cells. These references represent the crucial part of setups for practical realization of the meter unit - highly stable laser standards. Furthermore, not only in the most precise laboratory instruments, but also in less demanding interferometric measuring setups the frequency stabilization of the lasers throught the absorption in suitable media ensure the direct traceability to the fundamental standard of length. A set of absorption cells filled with different amounts of molecular iodine (different saturation pressure point of absorption media) was prepared and an agreement between expected and resulting spectral properties of these cells was observed and evaluated. The usage of borosilicate glass instead of common fused silica as a material for cells bodies represents an approach to simplify the manufacturing technology process and also reduces the overall cell costs. A great care must be taken to control/avoid the risk of absorption media contamination by impurities releasing from the cell walls. We introduce an iodine purity and spectral properties evaluation method based on measurement of linewidth of the hyperfine transitions. The proposed method was used for verification of great iodine purity of manufactured cells by comparison of spectral properties with cells traditionally made of fused silica glass with well known iodine purity. The results confirmed a great potential of proposed approaches.

  3. Spectral Methods for Magnetic Anomalies

    Science.gov (United States)

    Parker, R. L.; Gee, J. S.

    2013-12-01

    Spectral methods, that is, those based in the Fourier transform, have long been employed in the analysis of magnetic anomalies. For example, Schouten and MaCamy's Earth filter is used extensively to map patterns to the pole, and Parker's Fourier transform series facilitates forward modeling and provides an efficient algorithm for inversion of profiles and surveys. From a different, and perhaps less familiar perspective, magnetic anomalies can be represented as the realization of a stationary stochastic process and then statistical theory can be brought to bear. It is vital to incorporate the full 2-D power spectrum, even when discussing profile data. For example, early analysis of long profiles failed to discover the small-wavenumber peak in the power spectrum predicted by one-dimensional theory. The long-wavelength excess is the result of spatial aliasing, when energy leaks into the along-track spectrum from the cross-track components of the 2-D spectrum. Spectral techniques may be used to improve interpolation and downward continuation of survey data. They can also evaluate the reliability of sub-track magnetization models both across and and along strike. Along-strike profiles turn out to be surprisingly good indicators of the magnetization directly under them; there is high coherence between the magnetic anomaly and the magnetization over a wide band. In contrast, coherence is weak at long wavelengths on across-strike lines, which is naturally the favored orientation for most studies. When vector (or multiple level) measurements are available, cross-spectral analysis can reveal the wavenumber interval where the geophysical signal resides, and where noise dominates. One powerful diagnostic is that the phase spectrum between the vertical and along-path components of the field must be constant 90 degrees. To illustrate, it was found that on some very long Project Magnetic lines, only the lowest 10% of the wavenumber band contain useful geophysical signal. In this

  4. Numerical relativity and spectral methods

    Science.gov (United States)

    Grandclement, P.

    2016-12-01

    The term numerical relativity denotes the various techniques that aim at solving Einstein's equations using computers. Those computations can be divided into two families: temporal evolutions on the one hand and stationary or periodic solutions on the other one. After a brief presentation of those two classes of problems, I will introduce a numerical tool designed to solve Einstein's equations: the KADATH library. It is based on the the use of spectral methods that can reach high accuracy with moderate computational resources. I will present some applications about quasicircular orbits of black holes and boson star configurations.

  5. Spectral analysis of bedform dynamics

    DEFF Research Database (Denmark)

    Winter, Christian; Ernstsen, Verner Brandbyge; Noormets, Riko

    . An assessment of bedform migration was achieved, as the growth and displacement of every single constituent can be distinguished. It can be shown that the changes in amplitude remain small for all harmonic constituents, whereas the phase shifts differ significantly. Thus the harmonics can be classified....... The proposed method overcomes the above mentioned problems of common descriptive analysis as it is an objective and straightforward mathematical process. The spectral decomposition of superimposed dunes allows a detailed description and analysis of dune patterns and migration....

  6. Spectral Properties of Schwarzschild Instantons

    CERN Document Server

    Jante, Rogelio

    2016-01-01

    We study spectral properties of the Dirac and scalar Laplace operator on the Euclidean Schwarzschild space, both twisted by a family of abelian connections with anti-self-dual curvature. We show that the zero-modes of the gauged Dirac operator, first studied by Pope, take a particularly simple form in terms of the radius of the Euclidean time orbits, and interpret them in the context of geometric models of matter. For the gauged Laplace operator, we study the spectrum of bound states numerically and observe that it can be approximated with remarkable accuracy by that of the exactly solvable gauged Laplace operator on the Euclidean Taub-NUT space.

  7. Spectral Methods in Spatial Statistics

    Directory of Open Access Journals (Sweden)

    Kun Chen

    2014-01-01

    Full Text Available When the spatial location area increases becoming extremely large, it is very difficult, if not possible, to evaluate the covariance matrix determined by the set of location distance even for gridded stationary Gaussian process. To alleviate the numerical challenges, we construct a nonparametric estimator called periodogram of spatial version to represent the sample property in frequency domain, because periodogram requires less computational operation by fast Fourier transform algorithm. Under some regularity conditions on the process, we investigate the asymptotic unbiasedness property of periodogram as estimator of the spectral density function and achieve the convergence rate.

  8. [Spectral emissivity of thin films].

    Science.gov (United States)

    Zhong, D

    2001-02-01

    In this paper, the contribution of multiple reflections in thin film to the spectral emissivity of thin films of low absorption is discussed. The expression of emissivity of thin films derived here is related to the thin film thickness d and the optical constants n(lambda) and k(lambda). It is shown that in the special case d-->infinity the emissivity of thin films is equivalent to that of the bulk material. Realistic numerical and more precise general numerical results for the dependence of the emissivity on d, n(lambda) and k(lambda) are given.

  9. Segmentation of cDNA Microarray Images using Parallel Spectral Clustering

    Directory of Open Access Journals (Sweden)

    Sandrine MOUYSSET

    2013-05-01

    Full Text Available Microarray technology generates large amounts of expression level of genes to be analyzed simultaneously. This analysis implies microarray image segmentation to extract the quantitative information from spots. Spectral clustering is one of the most relevant unsupervised methods able to gather data without a priori information on shapes or locality. We propose and test on microarray images a parallel strategy for the Spectral Clustering method based on domain decomposition with a criterion to determine the number of clusters.

  10. Segmentation of cDNA Microarray Images using Parallel Spectral Clustering

    Directory of Open Access Journals (Sweden)

    Daniel RUIZ

    2013-05-01

    Full Text Available Microarray technology generates large amounts of expression level of genes to be analyzed simultaneously. This analysis implies microarray image segmentation to extract the quantitative information from spots. Spectral clustering is one of the most relevant unsupervised methods able to gather data without a priori information on shapes or locality. We propose and test on microarray images a parallel strategy for the Spectral Clustering method based on domain decomposition with a criterion to determine the number of clusters.

  11. Subnanosecond spectral diffusion measurement using photon correlation

    CERN Document Server

    Sallen, Gregory; Aichele, Thomas; André, Régis; Besombes, Lucien; Bougerol, Catherine; Richard, Maxime; Tatarenko, Serge; Kheng, Kuntheak; Poizat, Jean-Philippe; 10.1038/nphoton.2010.174

    2012-01-01

    Spectral diffusion is a result of random spectral jumps of a narrow line as a result of a fluctuating environment. It is an important issue in spectroscopy, because the observed spectral broadening prevents access to the intrinsic line properties. However, its characteristic parameters provide local information on the environment of a light emitter embedded in a solid matrix, or moving within a fluid, leading to numerous applications in physics and biology. We present a new experimental technique for measuring spectral diffusion based on photon correlations within a spectral line. Autocorrelation on half of the line and cross-correlation between the two halves give a quantitative value of the spectral diffusion time, with a resolution only limited by the correlation set-up. We have measured spectral diffusion of the photoluminescence of a single light emitter with a time resolution of 90 ps, exceeding by four orders of magnitude the best resolution reported to date.

  12. Language identification using spectral and prosodic features

    CERN Document Server

    Rao, K Sreenivasa; Maity, Sudhamay

    2015-01-01

    This book discusses the impact of spectral features extracted from frame level, glottal closure regions, and pitch-synchronous analysis on the performance of language identification systems. In addition to spectral features, the authors explore prosodic features such as intonation, rhythm, and stress features for discriminating the languages. They present how the proposed spectral and prosodic features capture the language specific information from two complementary aspects, showing how the development of language identification (LID) system using the combination of spectral and prosodic features will enhance the accuracy of identification as well as improve the robustness of the system. This book provides the methods to extract the spectral and prosodic features at various levels, and also suggests the appropriate models for developing robust LID systems according to specific spectral and prosodic features. Finally, the book discuss about various combinations of spectral and prosodic features, and the desire...

  13. Planck 2013 results. IX. HFI spectral response

    CERN Document Server

    Ade, P A R; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bobin, J; Bock, J J; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bridges, M; Bucher, M; Burigana, C; Cardoso, J -F; Catalano, A; Challinor, A; Chamballu, A; Chary, R -R; Chen, X; Chiang, L -Y; Chiang, H C; Christensen, P R; Church, S; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Comis, B; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Eriksen, H K; Falgarone, E; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Galeotta, S; Ganga, K; Giard, M; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Hansen, F K; Hanson, D; Harrison, D; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, T R; Jaffe, A H; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leahy, J P; Leonardi, R; Leroy, C; Lesgourgues, J; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Matthai, F; Mazzotta, P; McGehee, P; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; North, C; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Popa, L; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Roudier, G; Rusholme, B; Santos, D; Savini, G; Shellard, E P S; Spencer, L D; Starck, J -L; Stolyarov, V; Stompor, R; Sudiwala, R; Sureau, F; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Tavagnacco, D; Terenzi, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Yvon, D; Zacchei, A; Zonca, A

    2014-01-01

    The Planck High Frequency Instrument (HFI) spectral response was determined through a series of ground based tests conducted with the HFI focal plane in a cryogenic environment prior to launch. The main goal of the spectral transmission tests was to measure the relative spectral response (including out-of-band signal rejection) of all HFI detectors. This was determined by measuring the output of a continuously scanned Fourier transform spectrometer coupled with all HFI detectors. As there is no on-board spectrometer within HFI, the ground-based spectral response experiments provide the definitive data set for the relative spectral calibration of the HFI. The spectral response of the HFI is used in Planck data analysis and component separation, this includes extraction of CO emission observed within Planck bands, dust emission, Sunyaev-Zeldovich sources, and intensity to polarization leakage. The HFI spectral response data have also been used to provide unit conversion and colour correction analysis tools. Ver...

  14. Extended short-wavelength spectral response from InGaAs focal plane arrays

    Science.gov (United States)

    Hoelter, Theodore R.; Barton, Jeffrey B.

    2003-09-01

    InGaAs detector material used in near infrared focal plane arrays (NIR FPAs) has typically been limited in spectral response to a range from approximately 900 nm to 1700 nm. Through special processing techniques, the spectral response can be extended down through the visible spectrum and into the ultraviolet. Test results showing preliminary spectral response from 350nm to 1700 nm, responsivity, sensitivity, corrected uniformity and simultaneous imaging of NIR and visible signals will be presented along with a discussion of anticipated applications for this new sensor technology.

  15. Computational color technology

    CERN Document Server

    Kang, Henry R

    2006-01-01

    Henry Kang provides the fundamental color principles and mathematical tools to prepare the reader for a new era of color reproduction, and for subsequent applications in multispectral imaging, medical imaging, remote sensing, and machine vision. This book is intended to bridge the gap between color science and computational color technology, putting color adaptation, color constancy, color transforms, color display, and color rendition in the domain of vector-matrix representations and theories. Computational Color Technology deals with color digital images on the spectral level using vector-m

  16. Lunar Spectral Irradiance and Radiance (LUSI): New Instrumentation to Characterize the Moon as a Space-Based Radiometric Standard.

    Science.gov (United States)

    Smith, Allan W; Lorentz, Steven R; Stone, Thomas C; Datla, Raju V

    2012-01-01

    The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty(1) of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth's atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties.

  17. 美国NIST元素汞发生器的基准溯源传递方法%The Method of Prime Traceability and Delivery on Element Mercury Generator from the NIST in USA

    Institute of Scientific and Technical Information of China (English)

    王强; 周刚; 钟琪; 杨凯; 白勇; 田英明

    2014-01-01

    Overviewing the method of prime traceability and delivery on element mercury generator from the NIST in USA.USA NIST uses ID ICP/MS method to calculate the candidate mercury generator output concentra-tion,it adds known high pure 201 Hg0 gas to candidate element mercury generator output calibration gas,then abun-dance of the spiked isotope 201 Hg will be changed,the abundance ratio of 201 Hg/202 Hg will be measured by ICP/MS.This process completes mercury traceability which is from the prime SRM3133 to 201Hg2 +solution concen-tration,and from 201 Hg2 + solution concentration to element mercury generator.This method is for the vender prime to trace to NIST prime,it is good for us to establish the element mercury generator traceability method and capacity which is suitable for Chinese requirement.%综述了美国 NIST元素汞发生器的基准溯源传递方法,通过在输出的汞标准气体中混合加入已知高纯度的201 Hg0气体(201 Hg2+标准溶液还原雾化),并采用同位素稀释电感耦合等离子体/质谱法(ID ICP/MS)测量加标后201 Hg/202 Hg同位素丰度比例,计算出待溯源元素汞发生器输出的 Hg0质量浓度。该过程实现了从元素汞一级标准物质 SRM 3133到201 Hg2+标准溶液,再到元素汞发生器输出标准气体的溯源传递,完成了从 NIST元素汞基准到仪器供应商生产基准的一级溯源传递,为建立符合我国需求的元素汞溯源传递方法和形成元素汞发生器溯源传递能力提供借鉴。

  18. CMB spectral distortions and energy release in the early universe

    Science.gov (United States)

    Tashiro, Hiroyuki

    2014-06-01

    Measuring the spectral deviation of the cosmic microwave background (CMB) from the blackbody spectrum has become a focus of attention as a probe of the thermal history of the Universe. It has been more than 20 years since COBE/FIRAS's measurement, which showed excellent agreement between the CMB spectrum and a perfect blackbody spectrum. Significant developments in the technology since then have allowed us to improve the sensitivity of the absolute spectrum measurement by a factor of {˜ }10^4. Therefore, the physics related to the generation of CMB spectral distortions should now be investigated in greater detail. To probe the physics in the early universe and to open an observational window for new physics, various energy release mechanisms both in and beyond standard cosmology need to be studied. In this paper, we provide a review of the physics of CMB distortions and the energy release that creates CMB distortions in the early universe.

  19. Engineering dissipation with phononic spectral hole burning

    Science.gov (United States)

    Behunin, R. O.; Kharel, P.; Renninger, W. H.; Rakich, P. T.

    2017-03-01

    Optomechanics, nano-electromechanics, and integrated photonics have brought about a renaissance in phononic device physics and technology. Central to this advance are devices and materials supporting ultra-long-lived photonic and phononic excitations that enable novel regimes of classical and quantum dynamics based on tailorable photon-phonon coupling. Silica-based devices have been at the forefront of such innovations for their ability to support optical excitations persisting for nearly 1 billion cycles, and for their low optical nonlinearity. While acoustic phonon modes can persist for a similar number of cycles in crystalline solids at cryogenic temperatures, it has not been possible to achieve such performance in silica, as silica becomes acoustically opaque at low temperatures. We demonstrate that these intrinsic forms of phonon dissipation are greatly reduced (by >90%) by nonlinear saturation using continuous drive fields of disparate frequencies. The result is a form of steady-state phononic spectral hole burning that produces a wideband transparency window with optically generated phonon fields of modest (nW) powers. We developed a simple model that explains both dissipative and dispersive changes produced by phononic saturation. Our studies, conducted in a microscale device, represent an important step towards engineerable phonon dynamics on demand and the use of glasses as low-loss phononic media.

  20. Auditory evoked fields elicited by spectral, temporal, and spectral-temporal changes in human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Hidehiko eOkamoto

    2012-05-01

    Full Text Available Natural sounds contain complex spectral components, which are temporally modulated as time-varying signals. Recent studies have suggested that the auditory system encodes spectral and temporal sound information differently. However, it remains unresolved how the human brain processes sounds containing both spectral and temporal changes. In the present study, we investigated human auditory evoked responses elicited by spectral, temporal, and spectral-temporal sound changes by means of magnetoencephalography (MEG. The auditory evoked responses elicited by the spectral-temporal change were very similar to those elicited by the spectral change, but those elicited by the temporal change were delayed by 30 – 50 ms and differed from the others in morphology. The results suggest that human brain responses corresponding to spectral sound changes precede those corresponding to temporal sound changes, even when the spectral and temporal changes occur simultaneously.

  1. A Spectral Canonical Electrostatic Algorithm

    CERN Document Server

    Webb, Stephen D

    2015-01-01

    Studying single-particle dynamics over many periods of oscillations is a well-understood problem solved using symplectic integration. Such integration schemes derive their update sequence from an approximate Hamiltonian, guaranteeing that the geometric structure of the underlying problem is preserved. Simulating a self-consistent system over many oscillations can introduce numerical artifacts such as grid heating. This unphysical heating stems from using non-symplectic methods on Hamiltonian systems. With this guidance, we derive an electrostatic algorithm using a discrete form of Hamilton's Principle. The resulting algorithm, a gridless spectral electrostatic macroparticle model, does not exhibit the unphysical heating typical of most particle-in-cell methods. We present results of this using a two-body problem as an example of the algorithm's energy- and momentum-conserving properties.

  2. Active spectral imaging and mapping

    Science.gov (United States)

    Steinvall, Ove

    2014-04-01

    Active imaging and mapping using lasers as illumination sources have been of increasing interest during the last decades. Applications range from defense and security, remote sensing, medicine, robotics, and others. So far, these laser systems have mostly been based on a fix wavelength laser. Recent advances in lasers enable emission of tunable, multiline, or broadband emission, which together with the development of array detectors will extend the capabilities of active imaging and mapping. This paper will review some of the recent work on active imaging mainly for defense and security and remote sensing applications. A short survey of basic lidar relations and present fix wavelength laser systems is followed by a review of the benefits of adding the spectral dimension to active and/or passive electro-optical systems.

  3. Spectral emissivity of cirrus clouds

    Science.gov (United States)

    Beck, Gordon H.; Davis, John M.; Cox, Stephen K.

    1993-01-01

    The inference of cirrus cloud properties has many important applications including global climate studies, radiation budget determination, remote sensing techniques and oceanic studies from satellites. Data taken at the Parsons Kansas site during the FIRE II project are used for this study. On November 26 there were initially clear sky conditions gradually giving way to a progressively thickening cirrus shield over a period of a few hours. Interferometer radiosonde and lidar data were taken throughout this event. Two techniques are used to infer the downward spectral emittance of the observed cirrus layer. One uses only measurements and the other involves measurements and FASCODE III calculations. FASCODE III is a line-by line radiance/transmittance model developed at the Air Force Geophysics Laboratory.

  4. Spectral Selectivity Applied To Hybrid Concentration Systems

    Science.gov (United States)

    Hamdy, M. A.; Luttmann, F.; Osborn, D. E.; Jacobson, M. R.; MacLeod, H. A.

    1985-12-01

    The efficiency of conversion of concentrated solar energy can be improved by separating the solar spectrum into portions matched to specific photoquantum processes and the balance used for photothermal conversion. The basic approaches of spectrally selective beam splitters are presented. A detailed simulation analysis using TRNSYS is developed for a spectrally selective hybrid photovoltaic/photothermal concentrating system. The analysis shows definite benefits to a spectrally selective approach.

  5. Spectral mapping theorems a bluffer's guide

    CERN Document Server

    Harte, Robin

    2014-01-01

    Written by an author who was at the forefront of developments in multi-variable spectral theory during the seventies and the eighties, this guide sets out to describe in detail the spectral mapping theorem in one, several and many variables. The basic algebraic systems – semigroups, rings and linear algebras – are summarised, and then topological-algebraic systems, including Banach algebras, to set up the basic language of algebra and analysis. Spectral Mapping Theorems is written in an easy-to-read and engaging manner and will be useful for both the beginner and expert. It will be of great importance to researchers and postgraduates studying spectral theory.

  6. Spectral Lag Evolution among -Ray Burst Pulses

    Indian Academy of Sciences (India)

    Lan-Wei Jia; Yun-Feng Liang; En-Wei Liang

    2014-09-01

    We analyse the spectral lag evolution of -ray burst (GRB) pulses with observations by CGRO/BATSE. No universal spectral lag evolution feature and pulse luminosity-lag relation within a GRB is observed.Our results suggest that the spectral lag would be due to radiation physics and dynamics of a given emission episode, possibly due to the longer lasting emission in a lower energy band, and the spectral lag may not be an intrinsic parameter to discriminate the long and short GRBs.

  7. Autoregressive Spectral Estimation and Functional Inference.

    Science.gov (United States)

    1982-06-01

    spectral density function . Note that F(O) - 0, F(l) = 1, and (15) F(w) = f(w’) dw’, O<w<l...correlation function p(v) is summable, and its spectral density function f(w) is bounded above and below in the sense that the dynamic range of f(w) (2) DR...l The AR(-n) and MA(-) representations have important implications for spectral 6 analysis since they provide formulas for the spectral density function

  8. Pigment Identification of Paintings Based on Kubelka-Munk Theory and Spectral Images

    Science.gov (United States)

    Moghareh Abed, Farhad

    The preservation of cultural heritage and treatment thereof are delicate responsibilities that demand the best possible technologies and extreme care to avoid any irreversible loss. It necessitates a deep understanding of constituent materials, along with the analytical methods and cutting-edge technologies. Considering this direction, the goal of this dissertation is to promote the conservation procedures by providing an applicable workflow for spectral-based pigment identification. The proposed pipeline is a novel and practical aid for museum conservators for many aspects, such as inpainting, treatment and archiving of artwork. Spectral-based pigment identification algorithms rely on accurate spectral data, a subtractive mixing model and an effective unmixing algorithm. In this dissertation, the spectral data were obtained using a spectral image acquisition system as a feasible and non-destructive technique. A liquid-crystal tunable filter (LCTF) and a CCD camera were used for spectral measurement of the painting. The spectral accuracy and precision of the LCTF-based spectral acquisition system were assessed and enhanced. Of the common factors affecting the acquisition performance, capturing geometry, LCTF angular dependencies and spectral characterization algorithm were new contributions to the traditional workflow. The complexity of subtractive mixtures limits the effective application of linear unmixing algorithms for pigment identification. Accordingly, a new linear modification of single-constant Kubelka-Munk theory was derived to enable the use of available linear spectral unmixing algorithms for paint mixtures. A selection of geometric and iterative-based unmixing algorithms was applied to the LCTF spectral images in the subtractive mixing space using the defined subtractive linear model. Final sets of primary pigments were improved employing a pre-existing database of common pigments as a tool for practical inpainting procedures. The pigment maps, showing

  9. Metaoptics for Spectral and Spatial Beam Manipulation

    Science.gov (United States)

    Raghu Srimathi, Indumathi

    Laser beam combining and beam shaping are two important areas with applications in optical communications, high power lasers, and atmospheric propagation studies. In this dissertation, metaoptical elements have been developed for spectral and spatial beam shaping, and multiplexing. Beams carrying orbital angular momentum (OAM), referred to as optical vortices, have unique propagation properties. Optical vortex beams carrying different topological charges are orthogonal to each other and have low inter-modal crosstalk which allows for them to be (de)multiplexed. Efficient spatial (de)multiplexing of these beams have been carried out by using diffractive optical geometrical coordinate transformation elements. The spatial beam combining technique shown here is advantageous because the efficiency of the system is not dependent on the number of OAM states being combined. The system is capable of generating coaxially propagating beams in the far-field and the beams generated can either be incoherently or coherently multiplexed with applications in power scaling and dynamic intensity profile manipulations. Spectral beam combining can also be achieved with the coordinate transformation elements. The different wavelengths emitted by fiber sources can be spatially overlapped in the far-field plane and the generated beams are Bessel-Gauss in nature with enhanced depth of focus properties. Unique system responses and beam shapes in the far-field can be realized by controlling amplitude, phase, and polarization at the micro-scale. This has been achieved by spatially varying the structural parameters at the subwavelength scale and is analogous to local modification of material properties. With advancements in fabrication technology, it is possible to control not just the lithographic process, but also the deposition process. In this work, a unique combination of spatial structure variations in conjunction with the conformal coating properties of an atomic layer deposition tool

  10. Use of EO-1 Hyperion data to calculate spectral band adjustment factors (SBAF) between the L7 ETM+ and Terra MODIS sensors

    Science.gov (United States)

    Chander, Gyanesh; Mishra, N.; Helder, Dennis L.; Aaron, David; Choi, T.; Angal, A.; Xiong, X.

    2010-01-01

    Different applications and technology developments in Earth observations necessarily require different spectral coverage. Thus, even for the spectral bands designed to look at the same region of the electromagnetic spectrum, the relative spectral responses (RSR) of different sensors may be different. In this study, spectral band adjustment factors (SBAF) are derived using hyperspectral Earth Observing-1 (EO-1) Hyperion measurements to adjust for the spectral band differences between the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) and the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) top-of-atmosphere (TOA) reflectance measurements from 2000 to 2009 over the pseudo-invariant Libya 4 reference standard test site.

  11. Spectral properties of correlation matrices--towards enhanced spectral clustering.

    Science.gov (United States)

    Fulger, Daniel; Scalas, Enrico

    2011-01-01

    This chapter compiles some properties of eigenvalues and eigenvectors of correlation and other matrices constructed from uncorrelated as well as systematically correlated Gaussian noise. All results are based on simulations. The situations depicted in the settings are found in time series analysis as one extreme variant and in gene/protein profile analysis with micro-arrays as the other extreme variant of the possible scenarios for correlation analysis and clustering where random matrix theory might contribute. The main difference between both is the number of variables versus the number of observations. To what extent the results can be transferred is yet unclear. While random matrix theory as such makes statements about the statistical properties of eigenvalues and eigenvectors, the expectation is that these statements, if used in a proper way, will improve the clustering of genes for the detection of functional groups. In the course of the scenarios, the relation and interchangeability between the concepts of time, experiment, and realizations of random variables play an important role. The mapping between a classical random matrix ensemble and the micro-array scenario is not yet obvious. In any case, we can make statements about pitfalls and sources of false conclusions. We also develop an improved spectral clustering algorithm that is based on the properties of eigenvalues and eigenvectors of correlation matrices. We found it necessary to rehearse and analyse these properties from the bottom up starting at one extreme end of scenarios and moving to the micro-array scenario.

  12. Spectral calibration for convex grating imaging spectrometer

    Science.gov (United States)

    Zhou, Jiankang; Chen, Xinhua; Ji, Yiqun; Chen, Yuheng; Shen, Weimin

    2013-12-01

    Spectral calibration of imaging spectrometer plays an important role for acquiring target accurate spectrum. There are two spectral calibration types in essence, the wavelength scanning and characteristic line sampling. Only the calibrated pixel is used for the wavelength scanning methods and he spectral response function (SRF) is constructed by the calibrated pixel itself. The different wavelength can be generated by the monochromator. The SRF is constructed by adjacent pixels of the calibrated one for the characteristic line sampling methods. And the pixels are illuminated by the narrow spectrum line and the center wavelength of the spectral line is exactly known. The calibration result comes from scanning method is precise, but it takes much time and data to deal with. The wavelength scanning method cannot be used in field or space environment. The characteristic line sampling method is simple, but the calibration precision is not easy to confirm. The standard spectroscopic lamp is used to calibrate our manufactured convex grating imaging spectrometer which has Offner concentric structure and can supply high resolution and uniform spectral signal. Gaussian fitting algorithm is used to determine the center position and the Full-Width-Half-Maximum(FWHM)of the characteristic spectrum line. The central wavelengths and FWHMs of spectral pixels are calibrated by cubic polynomial fitting. By setting a fitting error thresh hold and abandoning the maximum deviation point, an optimization calculation is achieved. The integrated calibration experiment equipment for spectral calibration is developed to enhance calibration efficiency. The spectral calibration result comes from spectral lamp method are verified by monochromator wavelength scanning calibration technique. The result shows that spectral calibration uncertainty of FWHM and center wavelength are both less than 0.08nm, or 5.2% of spectral FWHM.

  13. Spectral images browsing using principal component analysis and set partitioning in hierarchical tree

    Science.gov (United States)

    Ma, Long; Zhao, Deping

    2011-12-01

    Spectral imaging technology have been used mostly in remote sensing, but have recently been extended to new area requiring high fidelity color reproductions like telemedicine, e-commerce, etc. These spectral imaging systems are important because they offer improved color reproduction quality not only for a standard observer under a particular illuminantion, but for any other individual exhibiting normal color vision capability under another illuminantion. A possibility for browsing of the archives is needed. In this paper, the authors present a new spectral image browsing architecture. The architecture for browsing is expressed as follow: (1) The spectral domain of the spectral image is reduced with the PCA transform. As a result of the PCA transform the eigenvectors and the eigenimages are obtained. (2) We quantize the eigenimages with the original bit depth of spectral image (e.g. if spectral image is originally 8bit, then quantize eigenimage to 8bit), and use 32bit floating numbers for the eigenvectors. (3) The first eigenimage is lossless compressed by JPEG-LS, the other eigenimages were lossy compressed by wavelet based SPIHT algorithm. For experimental evalution, the following measures were used. We used PSNR as the measurement for spectral accuracy. And for the evaluation of color reproducibility, ΔE was used.here standard D65 was used as a light source. To test the proposed method, we used FOREST and CORAL spectral image databases contrain 12 and 10 spectral images, respectively. The images were acquired in the range of 403-696nm. The size of the images were 128*128, the number of bands was 40 and the resolution was 8 bits per sample. Our experiments show the proposed compression method is suitable for browsing, i.e., for visual purpose.

  14. VNIR spectral modeling of Mars analogue rocks: first results

    Science.gov (United States)

    Pompilio, L.; Roush, T.; Pedrazzi, G.; Sgavetti, M.

    Knowledge regarding the surface composition of Mars and other bodies of the inner solar system is fundamental to understanding of their origin, evolution, and internal structures. Technological improvements of remote sensors and associated implications for planetary studies have encouraged increased laboratory and field spectroscopy research to model the spectral behavior of terrestrial analogues for planetary surfaces. This approach has proven useful during Martian surface and orbital missions, and petrologic studies of Martian SNC meteorites. Thermal emission data were used to suggest two lithologies occurring on Mars surface: basalt with abundant plagioclase and clinopyroxene and andesite, dominated by plagioclase and volcanic glass [1,2]. Weathered basalt has been suggested as an alternative to the andesite interpretation [3,4]. Orbital VNIR spectral imaging data also suggest the crust is dominantly basaltic, chiefly feldspar and pyroxene [5,6]. A few outcrops of ancient crust have higher concentrations of olivine and low-Ca pyroxene, and have been interpreted as cumulates [6]. Based upon these orbital observations future lander/rover missions can be expected to encounter particulate soils, rocks, and rock outcrops. Approaches to qualitative and quantitative analysis of remotely-acquired spectra have been successfully used to infer the presence and abundance of minerals and to discover compositionally associated spectral trends [7-9]. Both empirical [10] and mathematical [e.g. 11-13] methods have been applied, typically with full compositional knowledge, to chiefly particulate samples and as a result cannot be considered as objective techniques for predicting the compositional information, especially for understanding the spectral behavior of rocks. Extending the compositional modeling efforts to include more rocks and developing objective criteria in the modeling are the next required steps. This is the focus of the present investigation. We present results of

  15. Spectral Energy Distributions of SDSS Blazars

    Indian Academy of Sciences (India)

    H. Z. Li; L. E. Chen

    2014-09-01

    We compiled the radio, optical and X-ray data for SDSS sample, and presented broad band spectral index. The broad band energy distribution reveals that FSRQs and LBLs objects have similar spectral properties. However, HBLs have a separate distinct property. Even so, a unified scheme was also revealed from colour–colour diagram.

  16. Abnormal Raman spectral phenomenon of silicon nanowires

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Raman spectra of two one-dimensional silicon nanowire samples with different excitation wavelengths were measured and an abnormal phenomenon was discovered that the Raman spectral features change with the wavelengths of excitation. Closer analysis of the crystalline structure of samples and the changes in Raman spectral features showed that the abnormal behavior is the result of resonance Raman scattering selection effect.

  17. Measuring Collimator Infrared (IR) Spectral Transmission

    Science.gov (United States)

    2016-05-01

    TECHNICAL REPORT RDMR-WD-16-15 MEASURING COLLIMATOR INFRARED (IR) SPECTRAL TRANSMISSION Christopher L. Dobbins Weapons...Distribution Statement A: Approved for public release; distribution unlimited. DESTRUCTION NOTICE FOR CLASSIFIED DOCUMENTS...AND DATES COVERED Final 4. TITLE AND SUBTITLE Measuring Collimator Infrared (IR) Spectral Transmission 5. FUNDING NUMBERS 6. AUTHOR(S) Christopher L

  18. The Copernicus ultraviolet spectral atlas of Sirius

    Science.gov (United States)

    Rogerson, John B., Jr.

    1987-01-01

    A near-ultraviolet spectral atlas for the A1 V star Alpha CMa (Sirius) has been prepared from data taken by the Princeton spectrometer aboard the Copernicus satellite. The spectral region from 1649 to 3170 A has been scanned with a resolution of 0.1 A. The atlas is presented in graphs, and line identifications for the absorption features have been tabulated.

  19. Spectral stability of unitary network models

    Science.gov (United States)

    Asch, Joachim; Bourget, Olivier; Joye, Alain

    2015-08-01

    We review various unitary network models used in quantum computing, spectral analysis or condensed matter physics and establish relationships between them. We show that symmetric one-dimensional quantum walks are universal, as are CMV matrices. We prove spectral stability and propagation properties for general asymptotically uniform models by means of unitary Mourre theory.

  20. Spectral properties of supersymmetric shape invariant potentials

    Indian Academy of Sciences (India)

    Barnali Chakrabarti

    2008-01-01

    We present the spectral properties of supersymmetric shape invariant potentials (SIPs). Although the folded spectrum is completely random, unfolded spectrum shows that energy levels are highly correlated and absolutely rigid. All the SIPs exhibit harmonic oscillator-type spectral statistics in the unfolded spectrum. We conjecture that this is the reflection of shape invariant symmetry.

  1. Spectral analysis of individual realization LDA data

    NARCIS (Netherlands)

    Tummers, M.J.; Passchier, D.M.

    1998-01-01

    The estimation of the autocorrelation function (act) or the spectral density function (sdt) from LDA data poses unique data-processing problems. The random sampling times in LDA preclude the use of the spectral methods for equi-spaced samples. As a consequence, special data-processing algorithms are

  2. XSL : The X-Shooter Spectral Library

    NARCIS (Netherlands)

    Chen, Yanping; Trager, Scott; Peletier, Reynier; Lançon, Ariane

    2011-01-01

    We are building a new spectral library with the X-Shooter instrument on ESO's VLT: XSL, the X-Shooter Spectral Library. We present our progress in building XSL, which covers the wavelength range from the near-UV to the near-IR with a resolution of R~10 000. At the time of writing we have collected s

  3. XSL: The X-Shooter Spectral Library

    NARCIS (Netherlands)

    Chen, Yanping; Trager, Scott; Peletier, Reynier; Lançon, Ariane

    2011-01-01

    We are building a new spectral library with the X-Shooter instrument on ESO's VLT: XSL, the X-Shooter Spectral Library. We present our progress in building XSL, which covers the wavelength range from the near-UV to the near-IR with a resolution of R~10 000. At the time of writing we have collected s

  4. XSL : The X-Shooter Spectral Library

    NARCIS (Netherlands)

    Chen, Yanping; Trager, Scott; Peletier, Reynier; Lan¸con, Ariane

    2011-01-01

    We are building a new spectral library with the X-Shooter instrument on ESO’s VLT: XSL, the X-Shooter Spectral Library. We present our progress in building XSL, which covers the wavelength range from the near-UV to the near-IR with a resolution of R 10000. At the time of writing we have collected sp

  5. Spectral distance on the Moyal plane

    Energy Technology Data Exchange (ETDEWEB)

    Martinetti, Pierre [Universitaet Goettingen (Germany). Courant Centre

    2010-07-01

    We compute the spectral distance, defined in Connes' noncommutative geometry, in the Moyal plane. We find that the distance between the eigenstates m,m+1 of the quantum harmonic oscillator is proportional to m{sup -1/2}. We also show how to truncate the Moyal spectral triple in order to obtain quantum metric spaces in the sense of Rieffel.

  6. Basic Functional Analysis Puzzles of Spectral Flow

    DEFF Research Database (Denmark)

    Booss-Bavnbek, Bernhelm

    2011-01-01

    We explain an array of basic functional analysis puzzles on the way to general spectral flow formulae and indicate a direction of future topological research for dealing with these puzzles.......We explain an array of basic functional analysis puzzles on the way to general spectral flow formulae and indicate a direction of future topological research for dealing with these puzzles....

  7. Compact high-resolution spectral phase shaper

    NARCIS (Netherlands)

    Postma, S.; Walle, van der P.; Offerhaus, H.L.; Hulst, van N.F.

    2005-01-01

    The design and operation of a high-resolution spectral phase shaper with a footprint of only 7×10 cm2 is presented. The liquid-crystal modulator has 4096 elements. More than 600 independent degrees of freedom can be positioned with a relative accuracy of 1 pixel. The spectral shaping of pulses fro

  8. Spectral methods for partial differential equations

    Science.gov (United States)

    Hussaini, M. Y.; Streett, C. L.; Zang, T. A.

    1984-01-01

    Origins of spectral methods, especially their relation to the Method of Weighted Residuals, are surveyed. Basic Fourier, Chebyshev, and Legendre spectral concepts are reviewed, and demonstrated through application to simple model problems. Both collocation and tau methods are considered. These techniques are then applied to a number of difficult, nonlinear problems of hyperbolic, parabolic, elliptic, and mixed type. Fluid-dynamical applications are emphasized.

  9. Spectral Methods in Numerical Plasma Simulation

    DEFF Research Database (Denmark)

    Coutsias, E.A.; Hansen, F.R.; Huld, T.;

    1989-01-01

    An introduction is given to the use of spectral methods in numerical plasma simulation. As examples of the use of spectral methods, solutions to the two-dimensional Euler equations in both a simple, doubly periodic region, and on an annulus will be shown. In the first case, the solution is expanded...

  10. Active spectral imaging nondestructive evaluation (SINDE) camera

    Energy Technology Data Exchange (ETDEWEB)

    Simova, E.; Rochefort, P.A., E-mail: eli.simova@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    A proof-of-concept video camera for active spectral imaging nondestructive evaluation has been demonstrated. An active multispectral imaging technique has been implemented in the visible and near infrared by using light emitting diodes with wavelengths spanning from 400 to 970 nm. This shows how the camera can be used in nondestructive evaluation to inspect surfaces and spectrally identify materials and corrosion. (author)

  11. Quantitative spectrally resolved imaging through a spectrograph

    NARCIS (Netherlands)

    Tolboom, RAL; Sijtsema, NM; ter Meulen, JJ; Dam, N.J.

    2003-01-01

    A grating spectrograph can be used for spectrally selective two-dimensional imaging if it is operated with a broad entrance slit. The resulting intensity distribution in its exit plane is a one-dimensional convolution of the spatial and spectral distributions of incident light. We present a dedicate

  12. Spectral Envelopes - A Preliminary Report

    CERN Document Server

    Lawton, Wayne

    2012-01-01

    The spectral envelope S(F) of a subset of integers is the set of probability measures on the circle group that are weak star limits of squared moduli of trigonometric polynomials with frequencies in F. Fourier transforms of these measures are positive and supported in F - F but the converse generally fails. The characteristic function chiF of F is a binary sequence whose orbit closure gives a symbolic dynamical system O(F). Analytic properties of S(F) are related to dynamical properties of chiF. The Riemann-Lebesque lemma implies that if chiF is minimal, then S(F) is convex and hence S(F) is the closure of the convex hull of its extreme points Se(F). In this paper we (i) review the relationship between these concepts and the special case of the still open 1959 Kadison-Singer problem called Feichtinger's conjecture for exponential functions, (ii) partially characterize of elements in Se(F), for minimal chiF, in terms of ergodic properties of (O(F),lambda) where lambda is a shift invariant probability measure w...

  13. A Real-Time Infrared Ultra-Spectral Signature Classification Method via Spatial Pyramid Matching.

    Science.gov (United States)

    Mei, Xiaoguang; Ma, Yong; Li, Chang; Fan, Fan; Huang, Jun; Ma, Jiayi

    2015-07-03

    The state-of-the-art ultra-spectral sensor technology brings new hope for high precision applications due to its high spectral resolution. However, it also comes with new challenges, such as the high data dimension and noise problems. In this paper, we propose a real-time method for infrared ultra-spectral signature classification via spatial pyramid matching (SPM), which includes two aspects. First, we introduce an infrared ultra-spectral signature similarity measure method via SPM, which is the foundation of the matching-based classification method. Second, we propose the classification method with reference spectral libraries, which utilizes the SPM-based similarity for the real-time infrared ultra-spectral signature classification with robustness performance. Specifically, instead of matching with each spectrum in the spectral library, our method is based on feature matching, which includes a feature library-generating phase. We calculate the SPM-based similarity between the feature of the spectrum and that of each spectrum of the reference feature library, then take the class index of the corresponding spectrum having the maximum similarity as the final result. Experimental comparisons on two publicly-available datasets demonstrate that the proposed method effectively improves the real-time classification performance and robustness to noise.

  14. A Real-Time Infrared Ultra-Spectral Signature Classification Method via Spatial Pyramid Matching

    Directory of Open Access Journals (Sweden)

    Xiaoguang Mei

    2015-07-01

    Full Text Available The state-of-the-art ultra-spectral sensor technology brings new hope for high precision applications due to its high spectral resolution. However, it also comes with new challenges, such as the high data dimension and noise problems. In this paper, we propose a real-time method for infrared ultra-spectral signature classification via spatial pyramid matching (SPM, which includes two aspects. First, we introduce an infrared ultra-spectral signature similarity measure method via SPM, which is the foundation of the matching-based classification method. Second, we propose the classification method with reference spectral libraries, which utilizes the SPM-based similarity for the real-time infrared ultra-spectral signature classification with robustness performance. Specifically, instead of matching with each spectrum in the spectral library, our method is based on feature matching, which includes a feature library-generating phase. We calculate the SPM-based similarity between the feature of the spectrum and that of each spectrum of the reference feature library, then take the class index of the corresponding spectrum having the maximum similarity as the final result. Experimental comparisons on two publicly-available datasets demonstrate that the proposed method effectively improves the real-time classification performance and robustness to noise.

  15. ThermoData Engine (TDE): software implementation of the dynamic data evaluation concept. 6. Dynamic web-based data dissemination through the NIST Web Thermo Tables.

    Science.gov (United States)

    Kroenlein, Kenneth; Muzny, Chris D; Diky, Vladimir; Kazakov, Andrei F; Chirico, Robert D; Magee, Joseph W; Abdulagatov, Ilmutdin; Frenkel, Michael

    2011-06-27

    ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported recently in this journal. In the present paper, we describe the development of a World Wide Web-based interface to TDE evaluations of pure compound properties, including critical properties, phase boundary equilibria (vapor pressures, sublimation pressures, and crystal-liquid boundary pressures), densities, energetic properties, and transport properties. This includes development of a system for caching evaluation results to maintain high availability and an advanced window-in-window interface that leverages modern Web-browser technologies. Challenges associated with bringing the principal advantages of the TDE technology to the Web are described, as are compromises to maintain general access and speed of interaction while remaining true to the tenets of dynamic data evaluation. Future extensions of the interface and associated Web-services are outlined.

  16. CCPR-S1 Supplementary comparison for spectral radiance in the range of 220 nm to 2500 nm

    Science.gov (United States)

    Khlevnoy, Boris; Sapritsky, Victor; Rougie, Bernard; Gibson, Charles; Yoon, Howard; Gaertner, Arnold; Taubert, Dieter; Hartmann, Juergen

    2009-08-01

    In 1997, the Consultative Committee for Photometry and Radiometry (CCPR) initiated a supplementary comparison of spectral radiance in the wavelength range from 220 nm to 2500 nm (CCPR-S1) using tungsten strip-filament lamps as transfer standards. Five national metrology institutes (NMIs) took part in the comparison: BNM/INM (France), NIST (USA), NRC (Canada), PTB (Germany) and VNIIOFI (Russia), with VNIIOFI as the pilot laboratory. Each NMI provided the transfer lamps that were used to transfer their measurements to the pilot laboratory. The intercomparison sequence began with the participant measurements, then the pilot measurements, followed by a second set of measurements by the participant laboratory. The measurements were carried out from 1998 to 2002, with the final report completed in 2008. This paper presents the descriptions of measurement facilities and uncertainties of the participants, as well as the comparison results that were analysed in accordance with the Guidelines for CCPR Comparisons Report Preparation, and a re-evaluation of the results taking into account the instability of some of the transfer lamps. Excluding a few wavelengths, all participants agree with each other within ±1.5%. The disagreement decreases to approximately ±1.0% when the anomalous data are excluded from the analysis.

  17. X-ray diffraction patterns and diffracted intensity of Kα spectral lines of He-like ions

    Science.gov (United States)

    Goyal, Arun; Khatri, Indu; Singh, A. K.; Sharma, Rinku; Mohan, Man

    2017-09-01

    In the present paper, we have calculated fine-structure energy levels related to the configurations 1s2s, 1s2p, 1s3s and 1s3p by employing GRASP2K code. We have also computed radiative data for transitions from 1s2p 1 P1o, 1s2p 3 P2o, 1s2p 3 P1o and 1s2s 3S1 to the ground state 1s2. We have made comparisons of our presented energy levels and transition wavelengths with available results compiled by NIST and good agreement is achieved. We have also provided X-ray diffraction (XRD) patterns of Kα spectral lines, namely w, x, y and z of Cu XXVIII, Kr XXXV and Mo with diffraction angle and maximum diffracted intensity which is not published elsewhere in the literature. We believe that our presented results may be beneficial in determination of the order parameter, X-ray crystallography, solid-state drug analysis, forensic science, geological and medical applications.

  18. Contractive spectral triples for crossed products

    CERN Document Server

    Paterson, Alan L T

    2012-01-01

    Connes showed that spectral triples encode (noncommutative) metric information. Further, Connes and Moscovici in their metric bundle construction showed that, as with the Takesaki duality theorem, forming a crossed product spectral triple can substantially simplify the structure. In a recent paper, Bellissard, Marcolli and Reihani (among other things) studied in depth metric notions for spectral triples and crossed product spectral triples for $Z$-actions, with applications in number theory and coding theory. In the work of Connes and Moscovici, crossed products involving groups of diffeomorphisms and even of \\'{e}tale groupoids are required. With this motivation, the present paper develops part of the Bellissard-Marcolli-Reihani theory for a general discrete group action, and in particular, introduces coaction spectral triples and their associated metric notions. The isometric condition is replaced by the contractive condition.

  19. Broadband Spectral Study of Magnetar Bursts

    Science.gov (United States)

    Kirmizibayrak, Demet; Gogus, Ersin; Sasmaz Mus, Sinem; Kaneko, Yuki

    2016-07-01

    Magnetar bursts occur sporadically on random occasions, and every burst-active episode carries unique information about the bursting magnetar. Therefore, in-depth spectral and temporal analyses of each of the magnetar bursts provide new insights into the bursting and radiation mechanisms. There have been a number of studies over the last decade, investigating the spectral and temporal properties of magnetar bursts. The spectra of typical magnetar bursts were generally described with the Comptonized model or the sum of two blackbody functions. However, it was recently shown that the actual spectral nature of these bursts can be conclusively determined if the spectral analysis is performed on a wide energy coverage. We present the results of in-depth systematic broadband (2 - 250 keV) spectral analysis of a large number of bursts originated from three magnetars: SGR 1806-20, SGR 1900+14, and SGR J1550-5418, observed with the Rossi X-ray Timing Explorer.

  20. Spectral ratio method for measuring emissivity

    Science.gov (United States)

    Watson, K.

    1992-01-01

    The spectral ratio method is based on the concept that although the spectral radiances are very sensitive to small changes in temperature the ratios are not. Only an approximate estimate of temperature is required thus, for example, we can determine the emissivity ratio to an accuracy of 1% with a temperature estimate that is only accurate to 12.5 K. Selecting the maximum value of the channel brightness temperatures is an unbiased estimate. Laboratory and field spectral data are easily converted into spectral ratio plots. The ratio method is limited by system signal:noise and spectral band-width. The images can appear quite noisy because ratios enhance high frequencies and may require spatial filtering. Atmospheric effects tend to rescale the ratios and require using an atmospheric model or a calibration site. ?? 1992.

  1. Room temperature mid-IR single photon spectral imaging

    CERN Document Server

    Dam, Jeppe Seidelin; Tidemand-Lichtenberg, Peter

    2012-01-01

    Spectral imaging and detection of mid-infrared (mid-IR) wavelengths are emerging as an enabling technology of great technical and scientific interest; primarily because important chemical compounds display unique and strong mid-IR spectral fingerprints revealing valuable chemical information. While modern Quantum cascade lasers have evolved as ideal coherent mid-IR excitation sources, simple, low noise, room temperature detectors and imaging systems still lag behind. We address this need presenting a novel, field-deployable, upconversion system for sensitive, 2-D, mid-IR spectral imaging. Measured room temperature dark noise is 0.2 photons/spatial element/second, which is a billion times below the dark noise level of cryogenically cooled InSb cameras. Single photon imaging and up to 200 x 100 spatial elements resolution is obtained reaching record high continuous wave quantum efficiency of about 20 % for polarized incoherent light at 3 \\mum. The proposed method is relevant for existing and new mid-IR applicat...

  2. Priorities for Standards and Measurements to Accelerate Innovations in Nano-Electrotechnologies: Analysis of the NIST-Energetics-IEC TC 113 Survey.

    Science.gov (United States)

    Bennett, Herbert S; Andres, Howard; Pellegrino, Joan; Kwok, Winnie; Fabricius, Norbert; Chapin, J Thomas

    2009-01-01

    In 2008, the National Institute of Standards and Technology and Energetics Incorporated collaborated with the International Electrotechnical Commission Technical Committee 113 (IEC TC 113) on nano-electrotechnologies to survey members of the international nanotechnologies community about priorities for standards and measurements to accelerate innovations in nano-electrotechnologies. In this paper, we analyze the 459 survey responses from 45 countries as one means to begin building a consensus on a framework leading to nano-electrotechnologies standards development by standards organizations and national measurement institutes. The distributions of priority rankings from all 459 respondents are such that there are perceived distinctions with statistical confidence between the relative international priorities for the several items ranked in each of the following five Survey category types: 1) Nano-electrotechnology Properties, 2) Nano-electrotechnology Taxonomy: Products, 3) Nano-electrotechnology Taxonomy: Cross-Cutting Technologies, 4) IEC General Discipline Areas, and 5) Stages of the Linear Economic Model. The global consensus prioritizations for ranked items in the above five category types suggest that the IEC TC 113 should focus initially on standards and measurements for electronic and electrical properties of sensors and fabrication tools that support performance assessments of nano-technology enabled sub-assemblies used in energy, medical, and computer products.

  3. Spatial, Temporal and Spectral Satellite Image Fusion via Sparse Representation

    Science.gov (United States)

    Song, Huihui

    Remote sensing provides good measurements for monitoring and further analyzing the climate change, dynamics of ecosystem, and human activities in global or regional scales. Over the past two decades, the number of launched satellite sensors has been increasing with the development of aerospace technologies and the growing requirements on remote sensing data in a vast amount of application fields. However, a key technological challenge confronting these sensors is that they tradeoff between spatial resolution and other properties, including temporal resolution, spectral resolution, swath width, etc., due to the limitations of hardware technology and budget constraints. To increase the spatial resolution of data with other good properties, one possible cost-effective solution is to explore data integration methods that can fuse multi-resolution data from multiple sensors, thereby enhancing the application capabilities of available remote sensing data. In this thesis, we propose to fuse the spatial resolution with temporal resolution and spectral resolution, respectively, based on sparse representation theory. Taking the study case of Landsat ETM+ (with spatial resolution of 30m and temporal resolution of 16 days) and MODIS (with spatial resolution of 250m ~ 1km and daily temporal resolution) reflectance, we propose two spatial-temporal fusion methods to combine the fine spatial information of Landsat image and the daily temporal resolution of MODIS image. Motivated by that the images from these two sensors are comparable on corresponding bands, we propose to link their spatial information on available Landsat- MODIS image pair (captured on prior date) and then predict the Landsat image from the MODIS counterpart on prediction date. To well-learn the spatial details from the prior images, we use a redundant dictionary to extract the basic representation atoms for both Landsat and MODIS images based on sparse representation. Under the scenario of two prior Landsat

  4. Spectral Reconstruction for Obtaining Virtual Hyperspectral Images

    Science.gov (United States)

    Perez, G. J. P.; Castro, E. C.

    2016-12-01

    Hyperspectral sensors demonstrated its capabalities in identifying materials and detecting processes in a satellite scene. However, availability of hyperspectral images are limited due to the high development cost of these sensors. Currently, most of the readily available data are from multi-spectral instruments. Spectral reconstruction is an alternative method to address the need for hyperspectral information. The spectral reconstruction technique has been shown to provide a quick and accurate detection of defects in an integrated circuit, recovers damaged parts of frescoes, and it also aids in converting a microscope into an imaging spectrometer. By using several spectral bands together with a spectral library, a spectrum acquired by a sensor can be expressed as a linear superposition of elementary signals. In this study, spectral reconstruction is used to estimate the spectra of different surfaces imaged by Landsat 8. Four atmospherically corrected surface reflectance from three visible bands (499 nm, 585 nm, 670 nm) and one near-infrared band (872 nm) of Landsat 8, and a spectral library of ground elements acquired from the United States Geological Survey (USGS) are used. The spectral library is limited to 420-1020 nm spectral range, and is interpolated at one nanometer resolution. Singular Value Decomposition (SVD) is used to calculate the basis spectra, which are then applied to reconstruct the spectrum. The spectral reconstruction is applied for test cases within the library consisting of vegetation communities. This technique was successful in reconstructing a hyperspectral signal with error of less than 12% for most of the test cases. Hence, this study demonstrated the potential of simulating information at any desired wavelength, creating a virtual hyperspectral sensor without the need for additional satellite bands.

  5. A new vision of the post-NIST civil infrastructure program: the challenges of next-generation construction materials and processes

    Science.gov (United States)

    Wu, H. Felix; Wan, Yan

    2014-03-01

    Our nation's infrastructural systems are crumbling. The deteriorating process grows over time. The physical aging of these vital facilities and the remediation of their current critical state pose a key societal challenge to the United States. Current sensing technologies, while well developed in controlled laboratory environments, have not yet yielded tools for producing real-time, in-situ data that are adequately comprehensible for infrastructure decision-makers. The need for advanced sensing technologies is national because every municipality and state in the nation faces infrastructure management challenges. The need is critical because portions of infrastructure are reaching the end of their life-spans and there are few cost-effective means to monitor infrastructure integrity and to prioritize the renovation and replacement of infrastructure elements. New advanced sensing technologies that produce cost-effective inspection and real-time monitoring data, and that can also help or aid in meaningful interpretation of the acquired data, therefore will enhance the safety in regard to the public on structural integrity by issuing timely and accurate alert data for effective maintenance to avoid disasters happening. New advanced sensing technologies also allow more informed management of infrastructural investments by avoiding premature replacement of infrastructure and identifying those structures in need of immediate action to prevent from catastrophic failure. Infrastructure management requires that once a structural defect is detected, an economical and efficient repair be made. Advancing the technologies of repairing infrastructure elements in contact with water, road salt, and subjected to thermal changes requires innovative research to significantly extend the service life of repairs, lower the costs of repairs, and provide repair technologies that are suitable for a wide range of conditions. All these new technologies will provide increased lifetimes

  6. Report on the consultative committee for photometry and radiometry key comparison of regular spectral transmittance 2010 (CCPR-K6.2010)

    Science.gov (United States)

    Koo, Annette

    2017-01-01

    This report details the final results of the CCPR comparison on regular spectral transmittance carried out between 2010 and 2016. Scales held by 12 participating national metrology institutes were compared over the spectral range from 380 nm to 1000 nm and over the nominal transmittance range from 0.1% transmittance to 90% transmittance. Sets of five absorbing neutral density filters (nominal transmittance 0.1%, 1%, 10%, 50% and 90%) were measured firstly by the pilot (MSL) and then were sent out in a 'star' format, one to each other participant (A*STAR, KRISS, LNE-CNAM, MKEH, NIST, NMIJ, NMISA, NPL, NRC, PTB, VNIIOFI). This cycle was repeated twice and followed by a final measurement at the pilot. The stability of the filters allowed unilateral degrees of equivalence to be calculated for each participant. These showed that the scales held by the participants are broadly equivalent. The results indicate scope for some participants to improve their measurement claims. Where occasional non-equivalence was revealed, some revision of uncertainty budgets may also be required. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  7. Database and Library Development of Organic Species using Gas Chromatography and Mass Spectral Measurements in Support of the Mars Science Laboratory

    Science.gov (United States)

    Garcia, Raul; Mahaffy, Paul; Misra, Prabhakar

    2010-02-01

    Our work involves the development of an organic contaminants database that will allow us to determine which compounds are found here on Earth and would be inadvertently detected in the Mars soil and gaseous samples as impurities. It will be used for the Sample Analysis at Mars (SAM) instrumentation analysis in the Mars Science Laboratory (MSL) rover scheduled for launch in 2011. In order to develop a comprehensive target database, we utilize the NIST Mass Spectral Library, Automated Mass Spectral Deconvolution and Identification System (AMDIS) and Ion Fingerprint Deconvolution (IFD) software to analyze the GC-MS data. We have analyzed data from commercial samples, such as paint and polymers, which have not been implemented into the rover and are now analyzing actual data from pyrolyzation on the rover. We have successfully developed an initial target compound database that will aid SAM in determining whether the components being analyzed come from Mars or are contaminants from either the rover itself or the Earth environment and are continuing to make improvements and adding data to the target contaminants database. )

  8. Broadband analog to digital conversion with spatial-spectral holography

    Energy Technology Data Exchange (ETDEWEB)

    Babbitt, W. Randall [Spectrum Lab, Montana State University, Bozeman, MT 59717-3510 (United States)]. E-mail: babbitt@physics.montana.edu; Neifeld, Mark A. [Spectrum Lab, Montana State University, Bozeman, MT 59717-3510 (United States); Merkel, Kristian D. [Spectrum Lab, Montana State University, Bozeman, MT 59717-3510 (United States)

    2007-11-15

    A new approach to broadband photonic-assisted analog-to-digital converter (ADC) technology is proposed and analyzed. The core of the device is a spatial spectral holographic (SSH) material, which can directly record the signals of interest in the frequency domain. An SSH-ADC acts as a frequency-domain stretch processor, which leverages the high performance of conventional ADCs by converting high bandwidth input signals to low bandwidth output signals without loss of information. Analysis of a 10 GHz bandwidth SSH-ADC predicts that 10-bit performance can be achieved with currently available materials and components. SSH-ADC technology is scalable to bandwidths over 100 GHz with recently developed SSH materials. While the SSH-ADC is a transient digitizer, the spatial parallelism of SSH materials can be utilized to enable continuous digitization.

  9. Spectrally resolved laser-induced fluorescence for bioaerosols standoff detection

    Science.gov (United States)

    Buteau, Sylvie; Stadnyk, Laurie; Rowsell, Susan; Simard, Jean-Robert; Ho, Jim; Déry, Bernard; McFee, John

    2007-09-01

    An efficient standoff biological warfare detection capability could become an important asset for both defence and security communities based on the increasing biological threat and the limits of the presently existing protection systems. Defence R&D Canada (DRDC) has developed, by the end of the 90s, a standoff bioaerosol sensor prototype based on intensified range-gated spectrometric detection of Laser Induced Fluorescence (LIF). This LIDAR system named SINBAHD monitors the spectrally resolved LIF originating from inelastic interactions with bioaerosols present in atmospheric cells customizable in size and in range. SINBAHD has demonstrated the capability of near real-time detection and classification of bioaerosolized threats at multi-kilometre ranges. In spring 2005, DRDC has initiated the BioSense demonstration project, which combines the SINBAHD technology with a geo-referenced Near InfraRed (NIR) LIDAR cloud mapper. SINBAHD is now being used to acquire more signatures to add in the spectral library and also to optimize and test the new BioSense algorithm strategy. In September 2006, SINBAHD has participated in a two-week trial held at DRDC-Suffield where different open-air wet releases of live and killed bioagent simulants, growth media and obscurants were performed. An autoclave killing procedure was performed on two biological materials (Bacillus subtilis var globigii or BG, and Bacillus thuringiensis or Bt) before being aerosolized, disseminated and spectrally characterized with SINBAHD. The obtained results showed no significant impact of this killing process on their normalised spectral signature in comparison with their live counterparts. Correlation between the detection signals from SINBAHD, an array of slit samplers and a FLuorescent Aerosol Particle Sensor (C-FLAPS) was obtained and SINBAHD's sensitivity could then be estimated. At the 2006 trial, a detection limit of a few tens of Agent Containing Particles per Liter of Air (ACPLA) was obtained

  10. Face Recognition via Ensemble SIFT Matching of Uncorrelated Hyperspectral Bands and Spectral PCTs

    Science.gov (United States)

    2011-06-01

    Unsupervised Hyperspectral Target Detection Algorithm. Wright-Patterson AFB: Air Force Institute of Technology. Kirby, M., & Sirovich, L. (1990...Xu, Y., Hu, K., Tian, Y., & Peng, F. (2008). Classification of Hyperspectral imagery using SIFT for spectral matching. Image and Signal Processing...single hyperspectral band which also performs very well under temporal variation. 15. SUBJECT TERMS Face Recognition, SIFT, Ensemble Classification

  11. Nonlinear spectral imaging of biological tissues

    Science.gov (United States)

    Palero, J. A.

    2007-07-01

    The work presented in this thesis demonstrates live high resolution 3D imaging of tissue in its native state and environment. The nonlinear interaction between focussed femtosecond light pulses and the biological tissue results in the emission of natural autofluorescence and second-harmonic signal. Because biological intrinsic emission is generally very weak and extends from the ultraviolet to the visible spectral range, a broad-spectral range and high sensitivity 3D spectral imaging system is developed. Imaging the spectral characteristics of the biological intrinsic emission reveals the structure and biochemistry of the cells and extra-cellular components. By using different methods in visualizing the spectral images, discrimination between different tissue structures is achieved without the use of any stain or fluorescent label. For instance, RGB real color spectral images of the intrinsic emission of mouse skin tissues show blue cells, green hair follicles, and purple collagen fibers. The color signature of each tissue component is directly related to its characteristic emission spectrum. The results of this study show that skin tissue nonlinear intrinsic emission is mainly due to the autofluorescence of reduced nicotinamide adenine dinucleotide (phosphate), flavins, keratin, melanin, phospholipids, elastin and collagen and nonlinear Raman scattering and second-harmonic generation in Type I collagen. In vivo time-lapse spectral imaging is implemented to study metabolic changes in epidermal cells in tissues. Optical scattering in tissues, a key factor in determining the maximum achievable imaging depth, is also investigated in this work.

  12. Augmented Classical Least Squares Multivariate Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haaland, David M. (Albuquerque, NM); Melgaard, David K. (Albuquerque, NM)

    2005-01-11

    A method of multivariate spectral analysis, termed augmented classical least squares (ACLS), provides an improved CLS calibration model when unmodeled sources of spectral variation are contained in a calibration sample set. The ACLS methods use information derived from component or spectral residuals during the CLS calibration to provide an improved calibration-augmented CLS model. The ACLS methods are based on CLS so that they retain the qualitative benefits of CLS, yet they have the flexibility of PLS and other hybrid techniques in that they can define a prediction model even with unmodeled sources of spectral variation that are not explicitly included in the calibration model. The unmodeled sources of spectral variation may be unknown constituents, constituents with unknown concentrations, nonlinear responses, non-uniform and correlated errors, or other sources of spectral variation that are present in the calibration sample spectra. Also, since the various ACLS methods are based on CLS, they can incorporate the new prediction-augmented CLS (PACLS) method of updating the prediction model for new sources of spectral variation contained in the prediction sample set without having to return to the calibration process. The ACLS methods can also be applied to alternating least squares models. The ACLS methods can be applied to all types of multivariate data.

  13. Augmented Classical Least Squares Multivariate Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haaland, David M. (Albuquerque, NM); Melgaard, David K. (Albuquerque, NM)

    2005-07-26

    A method of multivariate spectral analysis, termed augmented classical least squares (ACLS), provides an improved CLS calibration model when unmodeled sources of spectral variation are contained in a calibration sample set. The ACLS methods use information derived from component or spectral residuals during the CLS calibration to provide an improved calibration-augmented CLS model. The ACLS methods are based on CLS so that they retain the qualitative benefits of CLS, yet they have the flexibility of PLS and other hybrid techniques in that they can define a prediction model even with unmodeled sources of spectral variation that are not explicitly included in the calibration model. The unmodeled sources of spectral variation may be unknown constituents, constituents with unknown concentrations, nonlinear responses, non-uniform and correlated errors, or other sources of spectral variation that are present in the calibration sample spectra. Also, since the various ACLS methods are based on CLS, they can incorporate the new prediction-augmented CLS (PACLS) method of updating the prediction model for new sources of spectral variation contained in the prediction sample set without having to return to the calibration process. The ACLS methods can also be applied to alternating least squares models. The ACLS methods can be applied to all types of multivariate data.

  14. Partial spectral analysis of hydrological time series

    Science.gov (United States)

    Jukić, D.; Denić-Jukić, V.

    2011-03-01

    SummaryHydrological time series comprise the influences of numerous processes involved in the transfer of water in hydrological cycle. It implies that an ambiguity with respect to the processes encoded in spectral and cross-spectral density functions exists. Previous studies have not paid attention adequately to this issue. Spectral and cross-spectral density functions represent the Fourier transforms of auto-covariance and cross-covariance functions. Using this basic property, the ambiguity is resolved by applying a novel approach based on the spectral representation of partial correlation. Mathematical background for partial spectral density, partial amplitude and partial phase functions is presented. The proposed functions yield the estimates of spectral density, amplitude and phase that are not affected by a controlling process. If an input-output relation is the subject of interest, antecedent and subsequent influences of the controlling process can be distinguished considering the input event as a referent point. The method is used for analyses of the relations between the rainfall, air temperature and relative humidity, as well as the influences of air temperature and relative humidity on the discharge from karst spring. Time series are collected in the catchment of the Jadro Spring located in the Dinaric karst area of Croatia.

  15. On the spectral formulation of Granger causality.

    Science.gov (United States)

    Chicharro, D

    2011-12-01

    Spectral measures of causality are used to explore the role of different rhythms in the causal connectivity between brain regions. We study several spectral measures related to Granger causality, comprising the bivariate and conditional Geweke measures, the directed transfer function, and the partial directed coherence. We derive the formulation of dependence and causality in the spectral domain from the more general formulation in the information-theory framework. We argue that the transfer entropy, the most general measure derived from the concept of Granger causality, lacks a spectral representation in terms of only the processes associated with the recorded signals. For all the spectral measures we show how they are related to mutual information rates when explicitly considering the parametric autoregressive representation of the processes. In this way we express the conditional Geweke spectral measure in terms of a multiple coherence involving innovation variables inherent to the autoregressive representation. We also link partial directed coherence with Sims' criterion of causality. Given our results, we discuss the causal interpretation of the spectral measures related to Granger causality and stress the necessity to explicitly consider their specific formulation based on modeling the signals as linear Gaussian stationary autoregressive processes.

  16. Systems and technologies for enhanced coastal maritime security

    Science.gov (United States)

    Carapezza, Edward M.; Bucklin, Ann

    2008-04-01

    This paper describes a design for an innovative command and control system for an intelligent coastal maritime security system. The architecture for this intelligent coastal maritime security system is derived from the forth generation real-time control (RCS) system architecture1 developed by the National Institute of Science and Technology (NIST) over the past twenty years. This command and control system is a decision support system for real-time monitoring, response and training for security scenarios that can be hosted at various locations along the coast of the United States where homeland security surveillance and response activities are required. Additionally, this paper describes the design for a derivative real-time simulation based environment that can be used as a state-of-art test bed for developing new hardware and software components to be integrated into previous versions of deployed real-time control systems.

  17. Multi-Spectral Detection of Microfluidic Separation Products.

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, Carl C.; Meagher, Robert

    2007-12-01

    The objectives of this project were to develop a new scientific tool for studies of chemical processes at the single molecule level, and to provide enhanced capabilities for multiplexed, ultrasensitive separations and immunoassays. We have combined microfluidic separation techniques with our newly developed technology for spectrally and temporally resolved detection of single molecules. The detection of individual molecules can reveal fluctuations in molecular conformations, which are obscured in ensemble measurements, and allows detailed studies of reaction kinetics such as ligand or antibody binding. Detection near the single molecule level also enables the use of correlation techniques to extract information, such as diffusion rates, from the fluorescence signal. The micro-fluidic technology offers unprecedented control of the chemical environment and flow conditions, and affords the unique opportunity to study biomolecules without immobilization. For analytical separations, the fluorescence lifetime and spectral resolution of the detection makes it possible to use multiple parameters for identification of separation products to improve the certainty of identification. We have successfully developed a system that can measure fluorescence spectra, lifetimes and diffusion constants of the components of mixtures separated in a microfluidic electrophoresis chip.

  18. Multi-spectral pyrometry—a review

    Science.gov (United States)

    Araújo, António

    2017-08-01

    In pyrometry measurements, the unknown target emissivity is a critical source of uncertainty, especially when the emissivity is low. Aiming to overcome this problem, various multi-spectral pyrometry systems and processing techniques have been proposed in the literature. Basically, all multi-spectral systems are based on the same principle: the radiation emitted by the target is measured at different channels having different spectral characteristics, and the emissivity is modelled as a function of wavelength with adjustable parameters to be obtained empirically, resulting in a system of equations whose solution is the target temperature and the parameters of the emissivity function. The present work reviews the most important multi-spectral developments. Concerning the spectral width of the measurement channels, multi-spectral systems are divided into multi-wavelength (monochromatic channels) and multi-band (wide-band channels) systems. Regarding the number of unknowns and equations (one equation per channel), pyrometry systems can either be determined (same number of unknowns and equations, having a unique solution) or overdetermined (more equations than unknowns, to be solved by least-squares). Generally, higher-order multi-spectral systems are overdetermined, since the uncertainty of the solutions obtained from determined systems increases as the number of channels increases, so that determined systems normally have less than four channels. In terms of the spectral characteristics of the measurement channels, narrow bands, far apart from each other and shifted towards lower wavelengths, seem to provide more accurate solutions. Many processing techniques have been proposed, but they strongly rely on the relationship between emissivity and wavelength, which is, in turn, strongly dependent on the characteristics of a particular target. Several accurate temperature and/or emissivity results have been reported, but no universally accepted multi-spectral technique has

  19. Short-wave infrared (SWIR) spectral imager based on Fabry-Perot interferometer for remote sensing

    Science.gov (United States)

    Mannila, Rami; Holmlund, Christer; Ojanen, Harri J.; Näsilä, Antti; Saari, Heikki

    2014-10-01

    VTT Technical Research Centre of Finland has developed a spectral imager for short-wave infrared (SWIR) wavelength range. The spectral imager is based on a tunable Fabry-Perot interferometer (FPI) accompanied by a commercial InGaAs Camera. The FPI consists of two dielectric coated mirrors separated by a tunable air gap. Tuning of the air gap tunes also transmitted wavelength and therefore FPI acts as a tunable band bass filter. The FPI is piezo-actuated and it uses three piezo-actuators in a closed capacitive feedback loop for air gap tuning. The FPI has multiple order transmission bands, which limit free spectral range. Therefore spectral imager contains two FPI in a stack, to make possible to cover spectral range of 1000 - 1700 nm. However, in the first tests imager was used with one FPI and spectral range was limited to 1100-1600 nm. The spectral resolution of the imager is approximately 15 nm (FWHM). Field of view (FOV) across the flight direction is 30 deg. Imaging resolution of the spectral imager is 256 x 320 pixels. The focal length of the optics is 12 mm and F-number is 3.2. This imager was tested in summer 2014 in an unmanned aerial vehicle (UAV) and therefore a size and a mass of the imager were critical. Total mass of the imager is approximately 1200 grams. In test campaign the spectral imager will be used for forest and agricultural imaging. In future, because results of the UAV test flights are promising, this technology can be applied to satellite applications also.

  20. Synthetic Hounsfield units from spectral CT data

    Science.gov (United States)

    Bornefalk, Hans

    2012-04-01

    Beam-hardening-free synthetic images with absolute CT numbers that radiologists are used to can be constructed from spectral CT data by forming ‘dichromatic’ images after basis decomposition. The CT numbers are accurate for all tissues and the method does not require additional reconstruction. This method prevents radiologists from having to relearn new rules-of-thumb regarding absolute CT numbers for various organs and conditions as conventional CT is replaced by spectral CT. Displaying the synthetic Hounsfield unit images side-by-side with images reconstructed for optimal detectability for a certain task can ease the transition from conventional to spectral CT.

  1. Bounds of Spectral Radii of Weighted Trees

    Institute of Scientific and Technical Information of China (English)

    杨华中; 胡冠章; 洪渊

    2003-01-01

    Graphs for the design of networks or electronic circuits are usually weighted and the spectrum of weighted graphs are often analyzed to solve problems. This paper discusses the spectrum and the spectral radii of trees with edge weights. We derive expressions for the spectrum and the spectral radius of a weighted star, together with the boundary limits of the spectral radii for weighted paths and weighted trees. The analysis uses the theory of nonnegative matrices and applies the "moving edge" technique. Some simple examples of weighted paths and trees are presented to explain the results. Then, we propose some open problems in this area.

  2. Spectral flow, index and the signature operator

    CERN Document Server

    Azzali, Sara

    2009-01-01

    We relate the spectral flow to the index for paths of selfadjoint Breuer-Fredholm operators affiliated to a semifinite von Neumann algebra, generalizing results of Robbin-Salamon and Pushnitski. Then we prove the vanishing of the von Neumann spectral flow for the tangential signature operator of a foliated manifold when the metric is varied. We conclude that the tangential signature of a foliated manifold with boundary does not depend on the metric. In the Appendix we reconsider integral formulas for the spectral flow of paths of bounded operators.

  3. Spectral Compressive Sensing with Polar Interpolation

    DEFF Research Database (Denmark)

    Fyhn, Karsten; Dadkhahi, Hamid; F. Duarte, Marco

    2013-01-01

    Existing approaches to compressive sensing of frequency-sparse signals focuses on signal recovery rather than spectral estimation. Furthermore, the recovery performance is limited by the coherence of the required sparsity dictionaries and by the discretization of the frequency parameter space....... In this paper, we introduce a greedy recovery algorithm that leverages a band-exclusion function and a polar interpolation function to address these two issues in spectral compressive sensing. Our algorithm is geared towards line spectral estimation from compressive measurements and outperforms most existing...

  4. [Modern spectral estimation of ICP-AES].

    Science.gov (United States)

    Zhang, Z; Jia, Q; Liu, S; Guo, L; Chen, H; Zeng, X

    2000-06-01

    The inductively coupled plasma atomic emission spectrometry (ICP-AES) and its signal characteristics were discussed using modern spectral estimation technique. The power spectra density (PSD) was calculated using the auto-regression (AR) model of modern spectra estimation. The Levinson-Durbin recursion method was used to estimate the model parameters which were used for the PSD computation. The results obtained with actual ICP-AES spectra and measurements showed that the spectral estimation technique was helpful for the better understanding about spectral composition and signal characteristics.

  5. Aspects of the Bosonic Spectral Action

    CERN Document Server

    Sakellariadou, Mairi

    2015-01-01

    A brief description of the elements of noncommutative spectral geometry as an approach to unification is presented. The physical implications of the doubling of the algebra are discussed. Some high energy phenomenological as well as various cosmological consequences are presented. A constraint in one of the three free parameters, namely the one related to the coupling constants at unification, is obtained, and the possible role of scalar fields is highlighted. A novel spectral action approach based upon zeta function regularisation, in order to address some of the issues of the traditional bosonic spectral action based on a cutoff function and a cutoff scale, is discussed.

  6. Spectral Imaging at the Microscale and Beyond

    Directory of Open Access Journals (Sweden)

    François Paquet-Mercier

    2014-05-01

    Full Text Available Here we give context to the special issue “Spectral Imaging at the Microscale and Beyond” in Sensors. We start with an introduction and motivation for the need for spectral imaging and then present important definitions and background concepts. Following this, we review new developments and applications in environmental monitoring, biomaterials, microfluidics, nanomaterials, healthcare, agriculture and food science, with a special focus on the articles published in the special issue. Some concluding remarks put the presented developments in context vis-à-vis the future of spectral imaging.

  7. Angle of arrival estimation using spectral interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Z.W.; Harrington, C.; Thiel, C.W.; Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Krishna Mohan, R., E-mail: krishna@spectrum.montana.ed [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)

    2010-09-15

    We have developed a correlative signal processing concept based on a Mach-Zehnder interferometer and spatial-spectral (S2) materials that enables direct mapping of RF spectral phase as well as power spectral recording. This configuration can be used for precise frequency resolved time delay estimation between signals received by a phased antenna array system that in turn could be utilized to estimate the angle of arrival. We present an analytical theoretical model and a proof-of-principle demonstration of the concept of time difference of arrival estimation with a cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm.

  8. Multi-Configuration Matched Spectral Filter Core Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes an open-architecture spectral gas sensor based on compressive sensing concepts employed for both spatial and spectral domains. Our matched spectral...

  9. Elementary linear algebra for advanced spectral problems

    OpenAIRE

    Sjoestrand, J.; Zworski, M

    2003-01-01

    We discuss the general method of Grushin problems, closely related to Shur complements, Feshbach projections and effective Hamiltonians, and describe various appearances in spectral theory, pdes, mathematical physics and numerical problems.

  10. Spectral theory of ordinary differential operators

    CERN Document Server

    Weidmann, Joachim

    1987-01-01

    These notes will be useful and of interest to mathematicians and physicists active in research as well as for students with some knowledge of the abstract theory of operators in Hilbert spaces. They give a complete spectral theory for ordinary differential expressions of arbitrary order n operating on -valued functions existence and construction of self-adjoint realizations via boundary conditions, determination and study of general properties of the resolvent, spectral representation and spectral resolution. Special attention is paid to the question of separated boundary conditions, spectral multiplicity and absolutely continuous spectrum. For the case nm=2 (Sturm-Liouville operators and Dirac systems) the classical theory of Weyl-Titchmarch is included. Oscillation theory for Sturm-Liouville operators and Dirac systems is developed and applied to the study of the essential and absolutely continuous spectrum. The results are illustrated by the explicit solution of a number of particular problems including th...

  11. Digital Forensics Analysis of Spectral Estimation Methods

    CERN Document Server

    Mataracioglu, Tolga

    2011-01-01

    Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message. In today's world, it is widely used in order to secure the information. In this paper, the traditional spectral estimation methods are introduced. The performance analysis of each method is examined by comparing all of the spectral estimation methods. Finally, from utilizing those performance analyses, a brief pros and cons of the spectral estimation methods are given. Also we give a steganography demo by hiding information into a sound signal and manage to pull out the information (i.e, the true frequency of the information signal) from the sound by means of the spectral estimation methods.

  12. Automated spectral classification using template matching

    Institute of Scientific and Technical Information of China (English)

    Fu-Qing Duan; Rong Liu; Ping Guo; Ming-Quan Zhou; Fu-Chao Wu

    2009-01-01

    An automated spectral classification technique for large sky surveys is pro-posed. We firstly perform spectral line matching to determine redshift candidates for an observed spectrum, and then estimate the spectral class by measuring the similarity be-tween the observed spectrum and the shifted templates for each redshift candidate. As a byproduct of this approach, the spectral redshift can also be obtained with high accuracy. Compared with some approaches based on computerized learning methods in the liter-ature, the proposed approach needs no training, which is time-consuming and sensitive to selection of the training set. Both simulated data and observed spectra are used to test the approach; the results show that the proposed method is efficient, and it can achieve a correct classification rate as high as 92.9%, 97.9% and 98.8% for stars, galaxies and quasars, respectively.

  13. On the spectral functions of scalar mesons

    CERN Document Server

    Giacosa, Francesco

    2007-01-01

    In this work we study the spectral functions of scalar mesons in one- and two-channel cases. When the propagators satisfy the K\\"allen-Lehman representation a normalized spectral function is obtained, allowing to take into account finite-width effects in the evaluation of decay rates. In the one-channel case, suitable to the light sigma and k mesons, the spectral function can deviate consistently from a Breit-Wigner shape. In the two-channel case with one subthreshold channel the evaluated spectral function is well approximated by a Flatte' distribution; when applying the study to the $a_0(980)$ and $f_0(980)$ mesons the three-level forbidden KK decay is analysed.

  14. Spectral Shifting in Nondestructive Assay Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Trellue, Holly Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nettleton, Anthony Steven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tutt, James Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Menlove, Howard Olsen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); LaFleur, Adrienne Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tobin, Stephen Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-17

    This project involves spectrum tailoring research that endeavors to better distinguish energies of gamma rays using different spectral material thicknesses and determine neutron energies by coating detectors with various materials.

  15. Spectral Psychoanalysis of Speech under Strain | Sharma ...

    African Journals Online (AJOL)

    Spectral Psychoanalysis of Speech under Strain. ... Different voice features from the speech signal to be influenced by strain are: loudness, fundamental frequency, jitter, zero-crossing rate, ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  16. Learning theory of distributed spectral algorithms

    Science.gov (United States)

    Guo, Zheng-Chu; Lin, Shao-Bo; Zhou, Ding-Xuan

    2017-07-01

    Spectral algorithms have been widely used and studied in learning theory and inverse problems. This paper is concerned with distributed spectral algorithms, for handling big data, based on a divide-and-conquer approach. We present a learning theory for these distributed kernel-based learning algorithms in a regression framework including nice error bounds and optimal minimax learning rates achieved by means of a novel integral operator approach and a second order decomposition of inverse operators. Our quantitative estimates are given in terms of regularity of the regression function, effective dimension of the reproducing kernel Hilbert space, and qualification of the filter function of the spectral algorithm. They do not need any eigenfunction or noise conditions and are better than the existing results even for the classical family of spectral algorithms.

  17. Spectral Imaging Visualization and Tracking System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA Earth Observation Mission need for innovative optical tracking systems, Physical Optics Corporation (POC) proposes to develop a new Spectral...

  18. Elementary linear algebra for advanced spectral problems

    OpenAIRE

    Sjoestrand, J.; Zworski, M.

    2003-01-01

    We discuss the general method of Grushin problems, closely related to Shur complements, Feshbach projections and effective Hamiltonians, and describe various appearances in spectral theory, pdes, mathematical physics and numerical problems.

  19. Algorithms for Spectral Decomposition with Applications

    Data.gov (United States)

    National Aeronautics and Space Administration — The analysis of spectral signals for features that represent physical phenomenon is ubiquitous in the science and engineering communities. There are two main...

  20. Spectral functions of hadrons in lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, Y.; Asakawa, M. [Nagoya Univ. (Japan). Dept. of Physics; Hatsuda, T. [Kyoto Univ. (Japan). Dept. of Physics

    2000-01-01

    Using the maximum entropy method, spectral functions of the pseudo-scalar and vector mesons are extracted from lattice Monte Carlo data of the imaginary time Green's functions. The resonance and continuum structures as well as the ground state peaks are successfully obtained. Error analysis of the resultant spectral functions is also given on the basis of the Bayes probability theory. (author)

  1. Hourly Spectral Variability of Mrk 421

    CERN Document Server

    Krennrich, F; Boyle, P J; Bradbury, S M; Buckley, J H

    2003-01-01

    Mrk 421 is the first TeV blazar found to exhibit significant spectral variability during strong flaring activity, showing hardening of the TeV spectrum in high emission states. Mrk 421 is also known to exhibit flux variability on time scales as short as 15 minutes. In this paper we present studies of hourly spectral variability of Mrk 421 in 2001 using data from the Whipple Observatory 10m gamma-ray telescope.

  2. Multi-spectral photoacoustic elasticity tomography

    Science.gov (United States)

    Liu, Yubin; Yuan, Zhen

    2016-01-01

    The goal of this work was to develop and validate a spectrally resolved photoacoustic imaging method, namely multi-spectral photoacoustic elasticity tomography (PAET) for quantifying the physiological parameters and elastic modulus of biological tissues. We theoretically and experimentally examined the PAET imaging method using simulations and in vitro experimental tests. Our simulation and in vitro experimental results indicated that the reconstructions were quantitatively accurate in terms of sizes, the physiological and elastic properties of the targets. PMID:27699101

  3. Rank-based camera spectral sensitivity estimation.

    Science.gov (United States)

    Finlayson, Graham; Darrodi, Maryam Mohammadzadeh; Mackiewicz, Michal

    2016-04-01

    In order to accurately predict a digital camera response to spectral stimuli, the spectral sensitivity functions of its sensor need to be known. These functions can be determined by direct measurement in the lab-a difficult and lengthy procedure-or through simple statistical inference. Statistical inference methods are based on the observation that when a camera responds linearly to spectral stimuli, the device spectral sensitivities are linearly related to the camera rgb response values, and so can be found through regression. However, for rendered images, such as the JPEG images taken by a mobile phone, this assumption of linearity is violated. Even small departures from linearity can negatively impact the accuracy of the recovered spectral sensitivities, when a regression method is used. In our work, we develop a novel camera spectral sensitivity estimation technique that can recover the linear device spectral sensitivities from linear images and the effective linear sensitivities from rendered images. According to our method, the rank order of a pair of responses imposes a constraint on the shape of the underlying spectral sensitivity curve (of the sensor). Technically, each rank-pair splits the space where the underlying sensor might lie in two parts (a feasible region and an infeasible region). By intersecting the feasible regions from all the ranked-pairs, we can find a feasible region of sensor space. Experiments demonstrate that using rank orders delivers equal estimation to the prior art. However, the Rank-based method delivers a step-change in estimation performance when the data is not linear and, for the first time, allows for the estimation of the effective sensitivities of devices that may not even have "raw mode." Experiments validate our method.

  4. Tunable spectral enhancement of fiber supercontinuum

    Science.gov (United States)

    Yeom, Dong-Il; Bolger, Jeremy A.; Marshall, Graham D.; Austin, Dane R.; Kuhlmey, Boris T.; Withford, Michael J.; de Sterke, C. Martijn; Eggleton, Benjamin J.

    2007-06-01

    We demonstrate tunable spectral enhancement of the supercontinuum generated in a microstructured fiber with a fiber long-period grating. The long-period grating leads to phase distortion and loss that, with subsequent high-intensity propagation in uniform fiber, evolves into an enhancement around the grating's resonant wavelengths. Wavelength tunability is achieved by varying the temperature or the ambient refractive index, and the spectral peak can be extinguished by immersing the grating in index-matching oil.

  5. Generalized Line Spectral Estimation via Convex Optimization

    OpenAIRE

    Heckel, Reinhard; Soltanolkotabi, Mahdi

    2016-01-01

    Line spectral estimation is the problem of recovering the frequencies and amplitudes of a mixture of a few sinusoids from equispaced samples. However, in a variety of signal processing problems arising in imaging, radar, and localization we do not have access directly to such equispaced samples. Rather we only observe a severely undersampled version of these observations through linear measurements. This paper is about such generalized line spectral estimation problems. We reformulate these p...

  6. Bayesian mixture models for spectral density estimation

    OpenAIRE

    Cadonna, Annalisa

    2017-01-01

    We introduce a novel Bayesian modeling approach to spectral density estimation for multiple time series. Considering first the case of non-stationary timeseries, the log-periodogram of each series is modeled as a mixture of Gaussiandistributions with frequency-dependent weights and mean functions. The implied model for the log-spectral density is a mixture of linear mean functionswith frequency-dependent weights. The mixture weights are built throughsuccessive differences of a logit-normal di...

  7. The Copernicus ultraviolet spectral atlas of Vega

    Science.gov (United States)

    Rogerson, John B., Jr.

    1989-01-01

    A near-ultraviolet spectral atlas for the A0 V star Alpha Lyr (Vega) has been prepared from data taken by the Princeton spectrometer aboard the Copernicus satellite. The spectral region from 2000 to 3187 A has been scanned with a resolution of 0.1 A. The atlas is presented in graphs with a normalized continuum, and an identification table for the absorption features has been prepared.

  8. Spectral ageing a new age perspective

    CERN Document Server

    Rawlings, S; Rawlings, Katherine M Blundell & Steve

    2002-01-01

    We present an up-to-date critique of the physical basis for the spectral ageing method. We find that the number of cases where this method may be meaningfully applied to deduce the ages of classical double radio sources is small indeed. This critique is much more than merely a re-expression of anxieties about the calibration of spectral ageing (which have been articulated by others in the past).

  9. Spectral dimension flow on continuum random multigraph

    CERN Document Server

    Giasemidis, Georgios; Zohren, Stefan

    2012-01-01

    We review a recently introduced effective graph approximation of causal dynamical triangulations (CDT), the multigraph ensemble. We argue that it is well suited for analytical computations and that it captures the physical degrees of freedom which are important for the reduction of the spectral dimension as observed in numerical simulations of CDT. In addition multigraph models allow us to study the relationship between the spectral dimension and the Hausdorff dimension, thus establishing a link to other approaches to quantum gravity

  10. New hyperspectral discrimination measure for spectral similarity

    Science.gov (United States)

    Du, Yingzi; Chang, Chein-I.; Ren, Hsuan; D'Amico, Francis M.; Jensen, James O.

    2003-09-01

    Spectral angle mapper (SAM) has been widely used as a spectral similarity measure for multispectral and hyperspectral image analysis. It has been shown to be equivalent to Euclidean distance when the spectral angle is relatively small. Most recently, a stochastic measure, called spectral information divergence (SID) has been introduced to model the spectrum of a hyperspectral image pixel as a probability distribution so that spectral variations can be captured more effectively in a stochastic manner. This paper develops a new hyperspectral spectral discriminant measure, which is a mixture of SID and SAM. More specifically, let xi and xj denote two hyperspectral image pixel vectors with their corresponding spectra specified by si and sj. SAM is the spectral angle of xi and xj and is defined by [SAM(si,sj)]. Similarly, SID measures the information divergence between xi and xj and is defined by [SID(si,sj)]. The new measure, referred to as (SID,SAM)-mixed measure has two variations defined by SID(si,sj)xtan(SAM(si,sj)] and SID(si,sj)xsin[SAM(si,sj)] where tan [SAM(si,sj)] and sin[SAM(si,sj)] are the tangent and the sine of the angle between vectors x and y. The advantage of the developed (SID,SAM)-mixed measure combines both strengths of SID and SAM in spectral discriminability. In order to demonstrate its utility, a comparative study is conducted among the new measure, SID and SAM where the discriminatory power of the (SID,SAM)-mixed measure is significantly improved over SID and SAM.

  11. Ionizing laser propagation and spectral phase determination

    Science.gov (United States)

    Mittelberger, D. E.; Nakamura, K.; Lehe, R.; Gonsalves, A. J.; Benedetti, C.; Mao, H.-S.; Daniels, J.; Dale, N.; Swanson, K. K.; Esarey, E.; Leemans, W. P.

    2017-03-01

    Ionization-induced blueshifting is investigated through INF&RNO simulations and experimental studies at the Berkeley Laboratory Laser Accelerator (BELLA) Center. The effects of spectral phase and optical compression are explored. An in-situ method for verifying the spectral phase of an intense laser pulse at focus is presented, based on the effects of optical compression on the morphology of the blueshifted laser spectra.

  12. Exact Spectral Dimension of the Random Surface

    CERN Document Server

    Goncharenko, Igor

    2009-01-01

    We propose a new method of the analytical computation of the spectral dimension which is based on the equivalence of the random walk and the q-state Potts model with non-zero magnetic field in the limit $q\\to 0$. Calculating the critical exponent of the magnetization of this model on the dynamically triangulated random surface by means of a matrix model technique we obtain that the spectral dimension of this surface is equal to two.

  13. CHP Technologies

    Science.gov (United States)

    Learn about CHP technologies, including reciprocating engines, combustion turbines, steam turbines, microturbines, fuel cells, and waste heat to power. Access the Catalog of CHP Technologies and the Biomass CHP Catalog of Technologies.

  14. Assistive Technology

    Science.gov (United States)

    ... Page Resize Text Printer Friendly Online Chat Assistive Technology Assistive technology (AT) is any service or tool that helps ... be difficult or impossible. For older adults, such technology may be a walker to improve mobility or ...

  15. New and improved proteomics technologies for understanding complex biological systems: addressing a grand challenge in the life sciences.

    Science.gov (United States)

    Hood, Leroy E; Omenn, Gilbert S; Moritz, Robert L; Aebersold, Ruedi; Yamamoto, Keith R; Amos, Michael; Hunter-Cevera, Jennie; Locascio, Laurie

    2012-09-01

    This White Paper sets out a Life Sciences Grand Challenge for Proteomics Technologies to enhance our understanding of complex biological systems, link genomes with phenotypes, and bring broad benefits to the biosciences and the US economy. The paper is based on a workshop hosted by the National Institute of Standards and Technology (NIST) in Gaithersburg, MD, 14-15 February 2011, with participants from many federal R&D agencies and research communities, under the aegis of the US National Science and Technology Council (NSTC). Opportunities are identified for a coordinated R&D effort to achieve major technology-based goals and address societal challenges in health, agriculture, nutrition, energy, environment, national security, and economic development.

  16. Spectral Karyotyping for identification of constitutional chromosomal abnormalities at a national reference laboratory

    Directory of Open Access Journals (Sweden)

    Anguiano Arturo

    2012-01-01

    Full Text Available Abstract Spectral karyotyping is a diagnostic tool that allows visualization of chromosomes in different colors using the FISH technology and a spectral imaging system. To assess the value of spectral karyotyping analysis for identifying constitutional supernumerary marker chromosomes or derivative chromosomes at a national reference laboratory, we reviewed the results of 179 consecutive clinical samples (31 prenatal and 148 postnatal submitted for spectral karyotyping. Over 90% of the cases were requested to identify either small supernumerary marker chromosomes (sSMCs or chromosomal exchange material detected by G-banded chromosome analysis. We also reviewed clinical indications of those cases with marker chromosomes in which chromosomal origin was identified by spectral karyotyping. Our results showed that spectral karyotyping identified the chromosomal origin of marker chromosomes or the source of derivative chromosomal material in 158 (88% of the 179 clinical cases; the identification rate was slightly higher for postnatal (89% compared to prenatal (84% cases. Cases in which the origin could not be identified had either a small marker chromosome present at a very low level of mosaicism (

  17. Parametrization of Minimal Spectral Factors of Discrete-Time Rational Spectral Densities

    OpenAIRE

    Baggio, Giacomo; Ferrante, Augusto

    2016-01-01

    In this paper, the problem of providing a complete parametrization of the minimal spectral factors of a discrete-time rational spectral density is considered. The desired parametrization is given in terms of the all-pass divisors of an all-pass function, related to the so-called phase function, under very mild assumptions on the given spectral density. This result provides a partial answer to a conjecture raised in [3].

  18. Multiplex immunoassay for persistent organic pollutants in tilapia: Comparison of imaging- and flow cytometry-based platforms using spectrally encoded paramagnetic microspheres

    Science.gov (United States)

    Recent developments in spectrally encoded microspheres (SEMs)-based technologies provide high multiplexing possibilities. Most SEMs-based assays required a flow cytometer with sophisticated fluidics and optics. The new imaging superparamagnetic SEMs-based platform transports SEMs with considerably ...

  19. SPHEREx: An All-Sky Spectral Survey

    Science.gov (United States)

    Bock, James; SPHEREx Science Team

    2016-01-01

    SPHEREx, a mission in NASA's Small Explorer (SMEX) program that was selected for Phase A in July 2015, is an all-sky survey satellite designed to address all three science goals in NASA's astrophysics division, in a single survey, with a single instrument. We will probe the physics of inflation by measuring non-Gaussianity by studying large-scale structure, surveying a large cosmological volume at low redshifts, complementing high-z surveys optimized to constrain dark energy. The origin of water and biogenic molecules will be investigated in all phases of planetary system formation - from molecular clouds to young stellar systems with protoplanetary disks - by measuring ice absorption spectra. We will chart the origin and history of galaxy formation through a deep survey mapping large-scale spatial power. Finally, SPHEREx will be the first all-sky near-infrared spectral survey, creating a legacy archive of spectra (0.75 - 4.8 um at R = 41.5 and 150) with high sensitivity using a cooled telescope with large mapping speed.SPHEREx will observe from a sun-synchronous low-earth orbit, covering the entire sky in a manner similar to IRAS, COBE and WISE. During its two-year mission, SPHEREx will produce four complete all-sky maps for constraining the physics of inflation. These same maps contain numerous high signal-to-noise absorption spectra to study water and biogenic ices. The orbit naturally covers two deep regions at the celestial poles, which we use for studying galaxy evolution. All aspects of the SPHEREx instrument and spacecraft have high heritage. SPHEREx requires no new technologies and carries large technical and resource margins on every aspect of the design. The projected instrument sensitivity, based on conservative performance estimates, meets the driving point source sensitivity requirement with 300 % margin.SPHEREx is a partnership between Caltech and JPL, following the successful management structure of the NuSTAR and GALEX SMEX missions. The spacecraft

  20. Mémoire et imagination chez les aliénistes esquiroliens et dans la troisième version de la Tentation de saint-Antoine de Flaubert : d’un savoir l’autre

    Directory of Open Access Journals (Sweden)

    Jean-Louis Cabanès

    2011-01-01

    Full Text Available A la suite d’Esquirol dans son traité Des maladies mentales de 1838, ceux que l’on appelait alors les « aliénistes » proposent de nouvelles théories de l’imagination qui, considérées dans leur ensemble, esquissent un cadre épistémique que Flaubert utilise comme cadre rhétorique dans la troisième version de la Tentation de saint-Antoine. Toutefois, l’auteur n’accepte pas l’assimilation de l’état dans lequel se trouve l’artiste lorsqu’il crée à une hallucination pathologique. Il s’oppose en cela à la théorie de Moreau de Tours ; en revanche, il se montre plus proche de la pensée de Brierre de Boismont (et de celle de l’historien Alfred Maury. Par cet usage intelligemment mitigé du cadre épistémique de l’aliénisme contemporain et par l’invention d’une prose poétique dont les soubassements théoriques annoncent certaines conceptions de Freud et de Nietzsche, Flaubert dépasse résolument les esquiroliens.

  1. USGS Digital Spectral Library splib06a

    Science.gov (United States)

    Clark, Roger N.; Swayze, Gregg A.; Wise, Richard A.; Livo, K. Eric; Hoefen, Todd M.; Kokaly, Raymond F.; Sutley, Stephen J.

    2007-01-01

    Introduction We have assembled a digital reflectance spectral library that covers the wavelength range from the ultraviolet to far infrared along with sample documentation. The library includes samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, plants, vegetation communities, microorganisms, and man-made materials. The samples and spectra collected were assembled for the purpose of using spectral features for the remote detection of these and similar materials. Analysis of spectroscopic data from laboratory, aircraft, and spacecraft instrumentation requires a knowledge base. The spectral library discussed here forms a knowledge base for the spectroscopy of minerals and related materials of importance to a variety of research programs being conducted at the U.S. Geological Survey. Much of this library grew out of the need for spectra to support imaging spectroscopy studies of the Earth and planets. Imaging spectrometers, such as the National Aeronautics and Space Administration (NASA) Airborne Visible/Infra Red Imaging Spectrometer (AVIRIS) or the NASA Cassini Visual and Infrared Mapping Spectrometer (VIMS) which is currently orbiting Saturn, have narrow bandwidths in many contiguous spectral channels that permit accurate definition of absorption features in spectra from a variety of materials. Identification of materials from such data requires a comprehensive spectral library of minerals, vegetation, man-made materials, and other subjects in the scene. Our research involves the use of the spectral library to identify the components in a spectrum of an unknown. Therefore, the quality of the library must be very good. However, the quality required in a spectral library to successfully perform an investigation depends on the scientific questions to be answered and the type of algorithms to be used. For example, to map a mineral using imaging spectroscopy and the mapping algorithm of Clark and others (1990a, 2003b

  2. Visible and near-infrared spectral signatures for adulteration assessment of extra virgin olive oil

    Science.gov (United States)

    Mignani, A. G.; Ciaccheri, L.; Ottevaere, H.; Thienpont, H.; Conte, L.; Marega, M.; Cichelli, A.; Attilio, C.; Cimato, A.

    2010-04-01

    Because of its high price, the extra virgin olive oil is frequently target for adulteration with lower quality oils. This paper presents an innovative optical technique capable of quantifying the adulteration of extra virgin olive oil caused by lowergrade olive oils. It relies on spectral fingerprinting the test liquid by means of diffuse-light absorption spectroscopy carried out by optical fiber technology in the wide 400-1700 nm spectral range. Then, a smart multivariate processing of spectroscopic data is applied for immediate prediction of adulterant concentration.

  3. Ultrasound-guided spectral photoacoustic imaging of hemoglobin oxygenation during development

    Science.gov (United States)

    Bayer, Carolyn L.; Wlodarczyk, Bogdan J.; Finnell, Richard H.; Emelianov, Stanislav Y.

    2017-01-01

    Few technologies are capable of imaging in vivo function during development. In this study, we have implemented spectral photoacoustic imaging to estimate tissue oxygenation longitudinally in pregnant mice. We used the spectral photoacoustic signal to estimate hemoglobin oxygen saturation within intact, in vivo mouse concepti from developmental day (E) 8.5 to E16.5—a first step towards functional imaging of the maternal-fetal environment. Future work will apply these methods to compare longitudinal functional changes during normal vs abnormal development of embryos, fetuses, and placentas. PMID:28270982

  4. Application of digital micromirror devices for spectral-response characterization of solar cells and photovoltaics

    Science.gov (United States)

    Fong, Alexandre Y.

    2010-02-01

    A key parameter in evaluating the performance of photovoltaic (PV) solar cells is characterization of electrical response to various incident source spectra. Conventional techniques utilize monochromators that emit single band-passes across a spectral region of interest. Since many solar cells respond differently at different broadband source light levels, a white bias light source that raises the overall light level to simulate the sun's broadband emission is typically introduced. However, such sources cannot render realistic solar continua. We present some initial results demonstrating how a spectrally-dispersed broadband source modulated with Texas Instruments' Digital Light Projection (DLP®) technology can be used to more faithfully synthesize solar spectra for this application.

  5. Modern Trends in Imaging X: Spectral Imaging in Preclinical Research and Clinical Pathology

    Directory of Open Access Journals (Sweden)

    Richard Levenson

    2012-01-01

    Full Text Available Spectral imaging methods are attracting increased interest from researchers and practitioners in basic science, pre-clinical and clinical arenas. A combination of better labeling reagents and better optics creates opportunities to detect and measure multiple parameters at the molecular and cellular level. These tools can provide valuable insights into the basic mechanisms of life, and yield diagnostic and prognostic information for clinical applications. There are many multispectral technologies available, each with its own advantages and limitations. This chapter will present an overview of the rationale for spectral imaging, and discuss the hardware, software and sample labeling strategies that can optimize its usefulness in clinical settings.

  6. [Estimation of Hunan forest carbon density based on spectral mixture analysis of MODIS data].

    Science.gov (United States)

    Yan, En-ping; Lin, Hui; Wang, Guang-xing; Chen, Zhen-xiong

    2015-11-01

    With the fast development of remote sensing technology, combining forest inventory sample plot data and remotely sensed images has become a widely used method to map forest carbon density. However, the existence of mixed pixels often impedes the improvement of forest carbon density mapping, especially when low spatial resolution images such as MODIS are used. In this study, MODIS images and national forest inventory sample plot data were used to conduct the study of estimation for forest carbon density. Linear spectral mixture analysis with and without constraint, and nonlinear spectral mixture analysis were compared to derive the fractions of different land use and land cover (LULC) types. Then sequential Gaussian co-simulation algorithm with and without the fraction images from spectral mixture analyses were employed to estimate forest carbon density of Hunan Province. Results showed that 1) Linear spectral mixture analysis with constraint, leading to a mean RMSE of 0.002, more accurately estimated the fractions of LULC types than linear spectral and nonlinear spectral mixture analyses; 2) Integrating spectral mixture analysis model and sequential Gaussian co-simulation algorithm increased the estimation accuracy of forest carbon density to 81.5% from 74.1%, and decreased the RMSE to 5.18 from 7.26; and 3) The mean value of forest carbon density for the province was 30.06 t · hm(-2), ranging from 0.00 to 67.35 t · hm(-2). This implied that the spectral mixture analysis provided a great potential to increase the estimation accuracy of forest carbon density on regional and global level.

  7. Solar spectral irradiance changes during cycle 24

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, S. V.; DeLand, M. T. [Also at NASA/Goddard Space Flight Center, Greenbelt, MD, USA. (United States)

    2014-07-10

    We use solar spectra obtained by the Ozone Monitoring Instrument (OMI) on board the Aura satellite to detect and follow long-term (years) and short-term (weeks) changes in the solar spectral irradiance (SSI) in the 265-500 nm spectral range. During solar Cycle 24, in the relatively line-free regions the SSI changed by ∼0.6% ± 0.2% around 265 nm. These changes gradually diminish to 0.15% ± 0.20% at 500 nm. All strong spectral lines and blends, with the notable exception of the upper Balmer lines, vary in unison with the solar 'continuum'. Besides the lines with strong chromospheric components, the most involved species include Fe I blends and all prominent CH, NH, and CN spectral bands. Following the general trend seen in the solar 'continuum', the variability of spectral lines also decreases toward longer wavelengths. The long-term solar cycle SSI changes are closely, to within the quoted 0.1%-0.2% uncertainties, matched by the appropriately adjusted short-term SSI variations derived from the 27 day rotational modulation cycles. This further strengthens and broadens the prevailing notion about the general scalability of the UV SSI variability to the emissivity changes in the Mg II 280 nm doublet on timescales from weeks to years. We also detect subtle deviations from this general rule: the prominent spectral lines and blends at λ ≳ 350 nm show slightly more pronounced 27 day SSI changes when compared to the long-term (years) trends. We merge the solar data from Cycle 21 with the current Cycle 24 OMI and GOME-2 observations and provide normalized SSI variations for the 170-795 nm spectral region.

  8. Validation of maritime spectral features

    Science.gov (United States)

    Hubler, Matthew J.

    quantifiable measurements. Thus combination of these new algorithms, buoy ground truth data, and more recent SAR technology deliver a powerful analytical tool. The eventual result of these algorithms could apply to meteorology, commercial shipping, disaster planning and recovery, ecology, and a vast assortment of other fields that would seek the wind patterns in open ocean scenes.

  9. Spectral variability of the particulate backscattering ratio

    Science.gov (United States)

    Whitmire, A. L.; Boss, E.; Cowles, T. J.; Pegau, W. S.

    2007-05-01

    The spectral dependency of the particulate backscattering ratio is relevant in the fields of ocean color inversion, light field modeling, and inferring particle properties from optical measurements. Aside from theoretical predictions for spherical, homogeneous particles, we have very limited knowledge of the actual in situ spectral variability of the particulate backscattering ratio. This work presents results from five research cruises that were conducted over a three-year period. Water column profiles of physical and optical properties were conducted across diverse aquatic environments that offered a wide range of particle populations. The main objective of this research was to examine the behavior of the spectral particulate backscattering ratio in situ, both in terms of its absolute magnitude and its variability across visible wavelengths, using over nine thousand 1-meter binned data points for each of five wavelengths of the spectral particulate backscattering ratio. Our analysis reveals no spectral dependence of the particulate backscattering ratio within our measurement certainty, and a geometric mean value of 0.013 for this dataset. This is lower than the commonly used value of 0.0183 from Petzold’s integrated volume scattering data. Within the first optical depth of the water column, the mean particulate backscattering ratio was 0.010.

  10. Multiple snapshot colored compressive spectral imager

    Science.gov (United States)

    Correa, Claudia V.; Hinojosa, Carlos A.; Arce, Gonzalo R.; Arguello, Henry

    2017-04-01

    The snapshot colored compressive spectral imager (SCCSI) is a recent compressive spectral imaging (CSI) architecture that senses the spatial and spectral information of a scene in a single snapshot by means of a colored mosaic FPA detector and a dispersive element. Commonly, CSI architectures allow multiple snapshot acquisition, yielding improved reconstructions of spatially detailed and spectrally rich scenes. Each snapshot is captured employing a different coding pattern. In principle, SCCSI does not admit multiple snapshots since the pixelated tiling of optical filters is directly attached to the detector. This paper extends the concept of SCCSI to a system admitting multiple snapshot acquisition by rotating the dispersive element, so the dispersed spatio-spectral source is coded and integrated at different detector pixels in each rotation. Thus, a different set of coded projections is captured using the same optical components of the original architecture. The mathematical model of the multishot SCCSI system is presented along with several simulations. Results show that a gain up to 7 dB of peak signal-to-noise ratio is achieved when four SCCSI snapshots are compared to a single snapshot reconstruction. Furthermore, a gain up to 5 dB is obtained with respect to state-of-the-art architecture, the multishot CASSI.

  11. Constructing Polynomial Spectral Models for Stars

    CERN Document Server

    Rix, Hans-Walter; Conroy, Charlie; Hogg, David W

    2016-01-01

    Stellar spectra depend on the stellar parameters and on dozens of photospheric elemental abundances. Simultaneous fitting of these $\\mathcal{N}\\sim \\,$10-40 model labels to observed spectra has been deemed unfeasible, because the number of ab initio spectral model grid calculations scales exponentially with $\\mathcal{N}$. We suggest instead the construction of a polynomial spectral model (PSM) of order $\\mathcal{O}$ for the model flux at each wavelength. Building this approximation requires a minimum of only ${\\mathcal{N}+\\mathcal{O}\\choose\\mathcal{O}}$ calculations: e.g. a quadratic spectral model ($\\mathcal{O}=\\,$2), which can then fit $\\mathcal{N}=\\,$20 labels simultaneously, can be constructed from as few as 231 ab initio spectral model calculations; in practice, a somewhat larger number ($\\sim\\,$300-1000) of randomly chosen models lead to a better performing PSM. Such a PSM can be a good approximation to ab initio spectral models only over a limited portion of label space, which will vary case by case. Y...

  12. Quantile regression applied to spectral distance decay

    Science.gov (United States)

    Rocchini, D.; Cade, B.S.

    2008-01-01

    Remotely sensed imagery has long been recognized as a powerful support for characterizing and estimating biodiversity. Spectral distance among sites has proven to be a powerful approach for detecting species composition variability. Regression analysis of species similarity versus spectral distance allows us to quantitatively estimate the amount of turnover in species composition with respect to spectral and ecological variability. In classical regression analysis, the residual sum of squares is minimized for the mean of the dependent variable distribution. However, many ecological data sets are characterized by a high number of zeroes that add noise to the regression model. Quantile regressions can be used to evaluate trend in the upper quantiles rather than a mean trend across the whole distribution of the dependent variable. In this letter, we used ordinary least squares (OLS) and quantile regressions to estimate the decay of species similarity versus spectral distance. The achieved decay rates were statistically nonzero (p species similarity when habitats are more similar. In this letter, we demonstrated the power of using quantile regressions applied to spectral distance decay to reveal species diversity patterns otherwise lost or underestimated by OLS regression. ?? 2008 IEEE.

  13. Infrared spectral properties of M giants

    CERN Document Server

    Sloan, G C; Ramirez, R M; Kraemer, K E; Engelke, C W

    2015-01-01

    We observed a sample of 20 M giants with the Infrared Spectrograph on the Spitzer Space Telescope. Most show absorption structure at 6.6-6.8 um which we identify as water vapor, and in some cases, the absorption extends from 6.4 um into the SiO band at 7.5 um. Variable stars show stronger H2O absorption. While the strength of the SiO fundamental at 8 um increases monotonically from spectral class K0 to K5, the dependence on spectral class weakens in the M giants. As with previously studied samples, the M giants show considerable scatter in SiO band strength within a given spectral class. All of the stars in our sample also show OH band absorption, most noticeably in the 14-17 um region. The OH bands behave much like the SiO bands, increasing in strength in the K giants but showing weaker dependence on spectral class in the M giants, and with considerable scatter. An examination of the photometric properties reveals that the V-K color may be a better indicator of molecular band strength than the spectral class...

  14. Spectral line polarimetry with a channeled polarimeter.

    Science.gov (United States)

    van Harten, Gerard; Snik, Frans; Rietjens, Jeroen H H; Martijn Smit, J; Keller, Christoph U

    2014-07-01

    Channeled spectropolarimetry or spectral polarization modulation is an accurate technique for measuring the continuum polarization in one shot with no moving parts. We show how a dual-beam implementation also enables spectral line polarimetry at the intrinsic resolution, as in a classic beam-splitting polarimeter. Recording redundant polarization information in the two spectrally modulated beams of a polarizing beam-splitter even provides the possibility to perform a postfacto differential transmission correction that improves the accuracy of the spectral line polarimetry. We perform an error analysis to compare the accuracy of spectral line polarimetry to continuum polarimetry, degraded by a residual dark signal and differential transmission, as well as to quantify the impact of the transmission correction. We demonstrate the new techniques with a blue sky polarization measurement around the oxygen A absorption band using the groundSPEX instrument, yielding a polarization in the deepest part of the band of 0.160±0.010, significantly different from the polarization in the continuum of 0.2284±0.0004. The presented methods are applicable to any dual-beam channeled polarimeter, including implementations for snapshot imaging polarimetry.

  15. Undecidability of the Spectral Gap (short version)

    CERN Document Server

    Cubitt, Toby; Wolf, Michael M

    2015-01-01

    The spectral gap -- the difference in energy between the ground state and the first excited state -- is one of the most important properties of a quantum many-body system. Quantum phase transitions occur when the spectral gap vanishes and the system becomes critical. Much of physics is concerned with understanding the phase diagrams of quantum systems, and some of the most challenging and long-standing open problems in theoretical physics concern the spectral gap, such as the Haldane conjecture that the Heisenberg chain is gapped for integer spin, proving existence of a gapped topological spin liquid phase, or the Yang-Mills gap conjecture (one of the Millennium Prize problems). These problems are all particular cases of the general spectral gap problem: Given a quantum many-body Hamiltonian, is the system it describes gapped or gapless? Here we show that this problem is undecidable, in the same sense as the Halting Problem was proven to be undecidable by Turing. A consequence of this is that the spectral gap...

  16. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, MR; Martin-Hernandez, NL; Lenorzer, A; de Koter, A; Tielens, AGGA

    2004-01-01

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of 0 main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on non-L

  17. Spectral phasor analysis allows rapid and reliable unmixing of fluorescence microscopy spectral images

    NARCIS (Netherlands)

    Fereidouni, F.; Bader, A.N.; Gerritsen, H.C.

    2012-01-01

    A new global analysis algorithm to analyse (hyper-) spectral images is presented. It is based on the phasor representation that has been demonstrated to be very powerful for the analysis of lifetime imaging data. In spectral phasor analysis the fluorescence spectrum of each pixel in the image is Fou

  18. Spectral polarimetric light-scattering by particulate media: 1. Theory of spectral Vector Radiative Transfer

    Science.gov (United States)

    Ceolato, Romain; Riviere, Nicolas

    2016-07-01

    Spectral polarimetric light-scattering by particulate media has recently attracted growing interests for various applications due to the production of directional broadband light sources. Here the spectral polarimetric light-scattering signatures of particulate media are simulated using a numerical model based on the spectral Vector Radiative Transfer Equation (VRTE). A microphysical analysis is conducted to understand the dependence of the light-scattering signatures upon the microphysical parameters of particles. We reveal that depolarization from multiple scattering results in remarkable spectral and directional features, which are simulated by our model over a wide spectral range from visible to near-infrared. We propose to use these features to improve the inversion of the scattering problem in the fields of remote sensing, astrophysics, material science, or biomedical.

  19. Comparison of Spectral-Only and Spectral/Spatial Face Recognition for Personal Identity Verification

    Directory of Open Access Journals (Sweden)

    Zhihong Pan

    2009-01-01

    Full Text Available Face recognition based on spatial features has been widely used for personal identity verification for security-related applications. Recently, near-infrared spectral reflectance properties of local facial regions have been shown to be sufficient discriminants for accurate face recognition. In this paper, we compare the performance of the spectral method with face recognition using the eigenface method on single-band images extracted from the same hyperspectral image set. We also consider methods that use multiple original and PCA-transformed bands. Lastly, an innovative spectral eigenface method which uses both spatial and spectral features is proposed to improve the quality of the spectral features and to reduce the expense of the computation. The algorithms are compared using a consistent framework.

  20. Comparison of Spectral-Only and Spectral/Spatial Face Recognition for Personal Identity Verification

    Science.gov (United States)

    Pan, Zhihong; Healey, Glenn; Tromberg, Bruce

    2009-12-01

    Face recognition based on spatial features has been widely used for personal identity verification for security-related applications. Recently, near-infrared spectral reflectance properties of local facial regions have been shown to be sufficient discriminants for accurate face recognition. In this paper, we compare the performance of the spectral method with face recognition using the eigenface method on single-band images extracted from the same hyperspectral image set. We also consider methods that use multiple original and PCA-transformed bands. Lastly, an innovative spectral eigenface method which uses both spatial and spectral features is proposed to improve the quality of the spectral features and to reduce the expense of the computation. The algorithms are compared using a consistent framework.

  1. Video rate spectral imaging using a coded aperture snapshot spectral imager.

    Science.gov (United States)

    Wagadarikar, Ashwin A; Pitsianis, Nikos P; Sun, Xiaobai; Brady, David J

    2009-04-13

    We have previously reported on coded aperture snapshot spectral imagers (CASSI) that can capture a full frame spectral image in a snapshot. Here we describe the use of CASSI for spectral imaging of a dynamic scene at video rate. We describe significant advances in the design of the optical system, system calibration procedures and reconstruction method. The new optical system uses a double Amici prism to achieve an in-line, direct view configuration, resulting in a substantial improvement in image quality. We describe NeAREst, an algorithm for estimating the instantaneous three-dimensional spatio-spectral data cube from CASSI's two-dimensional array of encoded and compressed measurements. We utilize CASSI's snapshot ability to demonstrate a spectral image video of multi-colored candles with live flames captured at 30 frames per second.

  2. Maximum a posteriori estimation of spectral reflectance from color image and multipoint spectral measurements.

    Science.gov (United States)

    Murakami, Yuri; Ietomi, Kunihiko; Yamaguchi, Masahiro; Ohyama, Nagaaki

    2007-10-01

    Accurate color image reproduction under arbitrary illumination can be realized if the spectral reflectance functions in a scene are obtained. Although multispectral imaging is one of the promising methods to obtain the reflectance of a scene, it is expected to reduce the number of color channels without significant loss of accuracy. This paper presents what we believe to be a new method for estimating spectral reflectance functions from color image and multipoint spectral measurements based on maximum a posteriori (MAP) estimation. Multipoint spectral measurements are utilized as auxiliary information to improve the accuracy of spectral reflectance estimated from image data. Through simulations, it is confirmed that the proposed method improves the estimation accuracy, particularly when a scene includes subjects that belong to various categories.

  3. LASER SPECTRAL ANALYSIS OF STRAIN MEASUREM ENT

    Institute of Scientific and Technical Information of China (English)

    姜耀东; 陈至达

    1994-01-01

    Modern optical theory has shown that the far field or Fraunhofer diffraction equipment is identical to the Fourier spectral analyzer. In the Fourier spectral analyzer the Fourier spectra or the Fraunhofer diffraction pattern of a graph is formed on the back foeal plane when a laser beam is directed on the graph lying on the front focal plane; the Fourier spectra of the graph is also subjected to change during the deformation of the graph. Through analyzing the change of Fourier spectra the deformation of the graph can be obtained. A few years ago, based on the above principles the authors proposed a new technique of strain measurement by laser spectral analysis. Demonstration and discussion will be made in detail in this paper.

  4. Spectral/hp element methods for CFD

    CERN Document Server

    Karniadakis, George Em

    1999-01-01

    Traditionally spectral methods in fluid dynamics were used in direct and large eddy simulations of turbulent flow in simply connected computational domains. The methods are now being applied to more complex geometries, and the spectral/hp element method, which incorporates both multi-domain spectral methods and high-order finite element methods, has been particularly successful. This book provides a comprehensive introduction to these methods. Written by leaders in the field, the book begins with a full explanation of fundamental concepts and implementation issues. It then illustrates how these methods can be applied to advection-diffusion and to incompressible and compressible Navier-Stokes equations. Drawing on both published and unpublished material, the book is an important resource for experienced researchers and for those new to the field.

  5. Temporal shape analysis via the spectral signature.

    Science.gov (United States)

    Bernardis, Elena; Konukoglu, Ender; Ou, Yangming; Metaxas, Dimitris N; Desjardins, Benoit; Pohl, Kilian M

    2012-01-01

    In this paper, we adapt spectral signatures for capturing morphological changes over time. Advanced techniques for capturing temporal shape changes frequently rely on first registering the sequence of shapes and then analyzing the corresponding set of high dimensional deformation maps. Instead, we propose a simple encoding motivated by the observation that small shape deformations lead to minor refinements in the spectral signature composed of the eigenvalues of the Laplace operator. The proposed encoding does not require registration, since spectral signatures are invariant to pose changes. We apply our representation to the shapes of the ventricles extracted from 22 cine MR scans of healthy controls and Tetralogy of Fallot patients. We then measure the accuracy score of our encoding by training a linear classifier, which outperforms the same classifier based on volumetric measurements.

  6. Automated spectral classification and the GAIA project

    Science.gov (United States)

    Lasala, Jerry; Kurtz, Michael J.

    1995-01-01

    Two dimensional spectral types for each of the stars observed in the global astrometric interferometer for astrophysics (GAIA) mission would provide additional information for the galactic structure and stellar evolution studies, as well as helping in the identification of unusual objects and populations. The classification of the large quantity generated spectra requires that automated techniques are implemented. Approaches for the automatic classification are reviewed, and a metric-distance method is discussed. In tests, the metric-distance method produced spectral types with mean errors comparable to those of human classifiers working at similar resolution. Data and equipment requirements for an automated classification survey, are discussed. A program of auxiliary observations is proposed to yield spectral types and radial velocities for the GAIA-observed stars.

  7. Sparsity and spectral properties of dual frames

    CERN Document Server

    Krahmer, Felix; Lemvig, Jakob

    2012-01-01

    We study sparsity and spectral properties of dual frames of a given finite frame. We show that any finite frame has a dual with no more than $n^2$ non-vanishing entries, where $n$ denotes the ambient dimension, and that for most frames no sparser dual is possible. Moreover, we derive an expression for the exact sparsity level of the sparsest dual for any given finite frame using a generalized notion of spark. We then study the spectral properties of dual frames in terms of singular values of the synthesis operator. We provide a complete characterization for which spectral patterns of dual frames are possible for a fixed frame. For many cases, we provide simple explicit constructions for dual frames with a given spectrum, in particular, if the constraint on the dual is that it be tight.

  8. Spectral determinants and quantum theta functions

    Science.gov (United States)

    Grassi, Alba

    2016-12-01

    It has been recently conjectured that the spectral determinants of operators associated to mirror curves can be expressed in terms of a generalization of theta functions, called quantum theta functions. In this paper we study the symplectic properties of these spectral determinants by expanding them around the point {\\hslash }=2π , where the quantum theta functions become conventional theta functions. We find that they are modular invariant, order by order, and we give explicit expressions for the very first terms of the expansion. Our derivation requires a detailed understanding of the modular properties of topological string free energies in the Nekrasov-Shatashvili limit. We derive these properties in a diagrammatic form. Finally, we use our results to provide a new test of the duality between topological strings and spectral theory.

  9. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

    Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

  10. Effective spectral dispersion of refractive index modulation

    Science.gov (United States)

    Vojtíšek, Petr; Květoň, Milan; Richter, Ivan

    2017-04-01

    For diffraction effects inside photopolymer materials, which act as volume diffraction systems (e.g. gratings), refractive index modulation is one of the key parameters. Due to its importance it is necessary to study this parameter from many perspectives, one of which is its value for different spectral components, i.e. its spectral dispersion. In this paper, we discuss this property and present an approach to experimental and numerical extraction and analysis (via rigorous coupled wave analysis and Cauchy’s empirical relation) of the effective dispersion of refractive index modulation based on an analysis of transmittance maps measured in an angular-spectral plane. It is indicated that the inclusion of dispersion leads to a significantly better description of the real grating behavior (which is often necessary in various design implementations of diffraction gratings) and that this estimation can be carried out for all the diffraction orders present.

  11. Maximum Spectral Luminous Efficacy of White Light

    CERN Document Server

    Murphy, T W

    2013-01-01

    As lighting efficiency improves, it is useful to understand the theoretical limits to luminous efficacy for light that we perceive as white. Independent of the efficiency with which photons are generated, there exists a spectrally-imposed limit to the luminous efficacy of any source of photons. We find that, depending on the acceptable bandpass and---to a lesser extent---the color temperature of the light, the ideal white light source achieves a spectral luminous efficacy of 250--370 lm/W. This is consistent with previous calculations, but here we explore the maximum luminous efficacy as a function of photopic sensitivity threshold, color temperature, and color rendering index; deriving peak performance as a function of all three parameters. We also present example experimental spectra from a variety of light sources, quantifying the intrinsic efficacy of their spectral distributions.

  12. Multiple spectral splits of supernova neutrinos.

    Science.gov (United States)

    Dasgupta, Basudeb; Dighe, Amol; Raffelt, Georg G; Smirnov, Alexei Yu

    2009-07-31

    Collective oscillations of supernova neutrinos swap the spectra f(nu(e))(E) and f(nu[over ](e))(E) with those of another flavor in certain energy intervals bounded by sharp spectral splits. This phenomenon is far more general than previously appreciated: typically one finds one or more swaps and accompanying splits in the nu and nu[over ] channels for both inverted and normal neutrino mass hierarchies. Depending on an instability condition, swaps develop around spectral crossings (energies where f(nu(e))=f(nu(x)), f(nu[over ](e))=f(nu[over ](x)) as well as E-->infinity where all fluxes vanish), and the widths of swaps are determined by the spectra and fluxes. Washout by multiangle decoherence varies across the spectrum and splits can survive as sharp spectral features.

  13. Backreaction Effects on Nonequilibrium Spectral Function

    CERN Document Server

    Mendizabal, Sebastian

    2016-01-01

    We show how to compute the spectral function for a scalar theory in two different scenarios: one which disregards back-reaction i.e. the response of the environment to the external particle, and the other one where back-reaction is considered. The calculation was performed using the Kadanoff-Baym equation through the Keldysh formalism. When back-reaction is neglected, the spectral function is equal to the equilibrium one, which can be represented as a Breit-Wigner distribution. When back-reaction is introduced we observed a damping in the spectral function of the thermal bath. Such behavior modifies the damping rate for particles created within the bath. This certainly implies phenomenological consequences right after the Big-Bang, when the primordial bath was created.

  14. Studying stellar populations at high spectral resolution

    CERN Document Server

    Bruzual, Gustavo A

    2007-01-01

    I describe very briefly the new libraries of empirical spectra of stars covering wide ranges of values of the atmospheric parameters Teff, log g, [Fe/H], as well as spectral type, that have become available in the recent past, among them the HNGSL, MILES, UVES-POP, ELODIE, and the IndoUS libraries. I show the results of using the IndoUS and the HNGSL libraries, as well as an atlas of theoretical model atmospheres, to build population synthesis models. These libraries are complementary in spectral resolution and wavelength coverage, and will prove extremely useful to describe spectral features expected in galaxy spectra from the NUV to the NIR. The fits to observed galaxy spectra using simple and composite stellar population models are discussed.

  15. Spectrally multiplexed chromatic confocal multipoint sensing.

    Science.gov (United States)

    Hillenbrand, Matthias; Lorenz, Lucia; Kleindienst, Roman; Grewe, Adrian; Sinzinger, Stefan

    2013-11-15

    We present a concept for chromatic confocal distance sensing that employs two levels of spectral multiplexing for the parallelized evaluation of multiple lateral measurement points; at the first level, the chromatic confocal principle is used to encode distance information within the spectral distribution of the sensor signal. For lateral multiplexing, the total spectral bandwidth of the sensor is split into bands. Each band is assigned to a different lateral measurement point by a segmented diffractive element. Based on this concept, we experimentally demonstrate a chromatic confocal three-point sensor that is suitable for harsh production environments, since it works with a single-point spectrometer and does not require scanning functionality. The experimental system has a working distance of more than 50 mm, a measurement range of 9 mm, and an axial resolution of 50 μm.

  16. Spectral sequences in smooth generalized cohomology

    CERN Document Server

    Grady, Daniel

    2016-01-01

    We consider spectral sequences in smooth generalized cohomology theories, including differential generalized cohomology theories. The main differential spectral sequences will be of the Atiyah-Hirzebruch (AHSS) type, where we provide a filtration by the Cech resolution of smooth manifolds. This allows for systematic study of torsion in differential cohomology. We apply this in detail to smooth Deligne cohomology, differential topological complex K-theory, and to a smooth extension of integral Morava K-theory that we introduce. In each case we explicitly identify the differentials in the corresponding spectral sequences, which exhibit an interesting and systematic interplay between (refinement of) classical cohomology operations, operations involving differential forms, and operations on cohomology with U(1) coefficients.

  17. Limiting Spectral Distribution of Sample Autocovariance Matrices

    CERN Document Server

    Basak, Anirban; Sen, Sanchayan

    2011-01-01

    The empirical spectral distribution (ESD) of the sample variance covariance matrix of i.i.d. observations under suitable moment conditions converges almost surely as the dimension tends to infinity. The limiting spectral distribution (LSD) is universal and is known in closed form with support [0, 4]. In this article we show that the ESD of the sample autocovariance matrix converges as the dimension increases, when the time series is a linear process with reasonable restriction on the coefficients. This limit does not depend on the distribution of the underlying driving i.i.d. sequence but in contrast to the sample variance covariance matrix, its support is unbounded. The limit moments are certain functions of the autocovariances. This limit is inconsistent in the sense that it does not coincide with the spectral distribution of the theoretical autocovariance matrix. However, if we consider a suitably tapered version of the autocovariance matrix, then its LSD also exists and is consistent. We also discuss the ...

  18. Double Fell bundles and Spectral triples

    CERN Document Server

    Martins, Rachel A D

    2007-01-01

    As a natural and canonical extension of Kumjian's Fell bundles over groupoids \\cite{fbg}, we give a definition for a double Fell bundle (a double category) over a double groupoid. We show that finite dimensional double category Fell line bundles tensored with their dual with $S^o$-reality satisfy the finite real spectral triples axioms but not necessarily orientability. This means that these product bundles with noncommutative algebras can be regarded as noncommutative compact manifolds more general than real spectral triples as they are not necessarily orientable. By construction, they unify the noncommutative geometry axioms and hence provide an algebraic enveloping structure for finite spectral triples to give the Dirac operator $D$ new algebraic and geometric structures that are otherwise missing in the transition from Fredholm operator to Dirac operator. The Dirac operator in physical applications as a result becomes less ad hoc. The new noncommutative space we present is a complex line bundle over a dou...

  19. Spectral Control of Mobile Robot Networks

    CERN Document Server

    Zavlanos, Michael M; Jadbabaie, Ali

    2010-01-01

    The eigenvalue spectrum of the adjacency matrix of a network is closely related to the behavior of many dynamical processes run over the network. In the field of robotics, this spectrum has important implications in many problems that require some form of distributed coordination within a team of robots. In this paper, we propose a continuous-time control scheme that modifies the structure of a position-dependent network of mobile robots so that it achieves a desired set of adjacency eigenvalues. For this, we employ a novel abstraction of the eigenvalue spectrum by means of the adjacency matrix spectral moments. Since the eigenvalue spectrum is uniquely determined by its spectral moments, this abstraction provides a way to indirectly control the eigenvalues of the network. Our construction is based on artificial potentials that capture the distance of the network's spectral moments to their desired values. Minimization of these potentials is via a gradient descent closed-loop system that, under certain convex...

  20. GIFTS SM EDU Radiometric and Spectral Calibrations

    Science.gov (United States)

    Tian, J.; Reisse, R. a.; Johnson, D. G.; Gazarik, J. J.

    2007-01-01

    The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) Sensor Module (SM) Engineering Demonstration Unit (EDU) is a high resolution spectral imager designed to measure infrared (IR) radiance using a Fourier transform spectrometer (FTS). The GIFTS instrument gathers measurements across the long-wave IR (LWIR), short/mid-wave IR (SMWIR), and visible spectral bands. The raw interferogram measurements are radiometrically and spectrally calibrated to produce radiance spectra, which are further processed to obtain atmospheric profiles via retrieval algorithms. This paper describes the processing algorithms involved in the calibration. The calibration procedures can be subdivided into three categories: the pre-calibration stage, the calibration stage, and finally, the post-calibration stage. Detailed derivations for each stage are presented in this paper.