The Third US Naval Observatory CCD Astrograph Catalog (UCAC3)
The third US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC3 was released at the IAU General Assembly on 2009 August 10. It is the first all-sky release in this series and contains just over 100 million objects, about 95 million of them with proper motions, covering about R = 8 to 16 magnitudes. Current epoch positions are obtained from the observations with the 20 cm aperture USNO Astrograph's "red lens", equipped with a 4k by 4k CCD. Proper motions are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. For most of the faint stars in the Southern Hemisphere the Yale/San Juan first epoch plates from the SPM program (YSJ1) form the basis for proper motions. These data are supplemented by all-sky ...
2010-01-01
Characterization of Adaptive Optics at Keck Observatory
Energy Technology Data Exchange (ETDEWEB)
In this paper, the adaptive optics (AO) system at Keck Observatory is characterized. The AO system is described in detail. The physical parameters of the lenslets, CCD and deformable mirror, the calibration procedures and the signal processing algorithms are explained. Results of sky performance tests are presented: the AO system is shown to deliver images with an average Strehl ratio of up to 0.37 at 1.59 {micro}m using a bright guide star. An error budget that is consistent with the observed image quality is presented.
2003-07-24
The Magdalena Ridge Observatory 2.4 m Telescope
EOS Technologies has been commissioned to design and build a unique 2.4m astronomical telescope for the Magdalena Ridge Observatory. This telescope utilizes a high quality primary mirror and cell from a now decommissioned military application. This paper describes the project and gives an overview of the telescope design. The Magdalena Ridge Observatory (MRO) 2.4 meter telescope will be primarily utilized to observe, track, and characterize solar system astronomical targets, Earth satellites, space vehicles, and terrestrial military targets. The telescope's rapid tracking (slew rates are 10o/sec) will allow it to move to any target and acquire data within one minute of receipt of notice. In this way, the telescope will be used to capitalize on targets of opportunity that occur in asteroid studies (e.g., Near Earth Objects) and in astrophysics, such as gamma ray bursts and other transient phenomena. Planned instrumentation includes a ...
2006-07-01
Rayleigh Laser Guide Star Systems UnISIS Bow Tie Shutter and CCD39 Wavefront Camera
Laser guide star systems based on Rayleigh scattering require some means to deal with the flash of low altitude laser light that follows immediately after each laser pulse. These systems also need a fast shutter to isolate the high altitude portion of the focused laser beam to make it appear star-like to the wavefront sensor. We describe how these tasks are accomplished with UnISIS, the Rayleigh laser guided adaptive optics system at the Mt. Wilson Observatory 2.5-m telescope. We use several methods: a 10,000 RPM rotating disk, dichroics, a fast sweep and clear mode of the CCD readout electronics on a 10 $\\mu$s timescale, and a Pockel's cell shutter system. The Pockel's cell shutter would be conventional in design if the laser light were naturally polarized, but the UnISIS 351 nm laser is unpolarized. So we have designed and put into operation a dual Pockel's cell shutter in a unique bow tie arrangement.
2002-01-01
Course and Curriculum Development Program, Evaluation Report
... grants to adopt or adapt courses and materials developed by CCD projects at other institutions, and ... to adopt or adapt CCD-developed courses and materials. -iv- Accomplishments The CCD program has ...
Morphology, stellar kinematics and dynamics of barred galaxies
International Nuclear Information System (INIS)
... Netherlands Kormendy, J. Dominion Astrophysical Observatory, Victoria, British
1982-08-09
International Nuclear Information System (INIS)
(Jun 1974). United States Kormendy, J. Hale Observatories, Pasadena,
Iao: The New Adaptive Optics Visible Imaging and ...
... is the sensor that converts incoming photons into a ... with CCD foundries to acquire such a sensor. ... 2007, Journal of Spacecraft and Rockets, 44, 910 ...
2008-09-01
Hawaiian Volcano Observatory 1956 through 1985 Administrative...
Survey - science for a changing world USGS Home Contact USGS Search USGS Hawaiian Volcano Observatory U.S. Geological Survey Open-File Reports 2007-1316 through 2007-1354...
2011-09-24
Tidal effects as criteria for membership in small groups of galaxies: Application to VV 166
International Nuclear Information System (INIS)
United States Kormendy, J. Sargent, WLW Hale Observatories, California
Program for Women and Girls 1997 Awardee Meeting
... University of Maryland. Participants Doris Ash Chabot Observatory & Science Center Krishna Athreya ...
Development of ARIES Baker-Nunn camera to a wide-field Imaging Telescope with CCD
ARIES Baker-Nunn Schmidt telescope project is converting a Baker-Nunn satellite tracking camera for Astronomical research. Original Baker-Nunn camera produces an extremely large (5X30 degree) curved focal plane at the prime focus for photographic imaging. We present here the re-designing of the camera produces a wide (4 X 4 degree) flat field of view for CCD imaging observations, which have many scientific potentials in Astronomy. Imaging performance of the CCD camera is also estimated.
2009-01-01
Typhoon Aere : Image of the Day - NASA Earth Observatory
Aug 25, 2004 ... The Tropical Rainfall Measuring Mission or TRMM satellite provided this image of Typhoon Aere over the western Philippine Sea as it was ...
Tropical Deforestation : Feature Articles - NASA Earth Observatory
Mar 30, 2007 ... Tropical forests are home to half the Earth's species, and their trees are an immense standing reservoir of carbon. Deforestation will have ...
Rio Negro Floodplain, Patagonia, Argentina - NASA Earth Observatory
Feb 15, 2010 ... This astronaut photo from January 4, 2010, shows meander scars and oxbow lakes in the floodplain of the Rio Negro in South America.
Satellite Observations of the Southeast Pacific Intertropical Convergence Zone During 1993-1998, Halpern, D.; Hung, C.-W., Journal of Geophysical Research ? ...
NASA's Next Major Space Observatory - Flight Projects - NASA
of Earth Science data and information management capabilities. Dale Schulz/400 . For your exceptional achievement in leading the joint LaRC/GSFC team in ...
Earthquakes, Hurricanes and Stubborn ... - NASA Earth Observatory
Aug 23, 2011 ... Earthquakes, Hurricanes and Stubborn Instruments ... And if earthquakes and stubborn instruments aren't enough, there's this giant hurricane ...
BIG BEAR SOLAR OBSERVATORY - NASA Technical Report Server (NTRS)
replacing the KDP crystal, and introducing computer programs for accumulation of an almost unlimited number of frames. The calibration procedure using solar ...
...Observatory Edinburgh SkyView Virtual Observatory Solar System Simulator Space Telescope Science Institute Space Weather : A Research Perspective Subaru Telescope Project Two Micron All ...Universities for Research in Astronomy Subjects: space observation DeweyClass: 522 Resource type: index Space Weather : A Research Perspective Documents discussing space weather , the ...elements of near-Earth space, Earth-space meteorology and practical consequences of space weather . Glossary included. Author: National Academy of ...
Comparative evolution of various CCD image sensors hardening techniques with ionizing radiation
International Nuclear Information System (INIS)
This paper reviews various techniques to harden Charged Coupled Device (CCD) sensors and the results after irradiation of three Thomson n buried channel CCDs having a different degree of hardening. It describes the major irradiation effects on CCD performances and it makes a comparison of the results between the different hardening levels. It shows good results on dark voltage after ionizing radiation for TH 7863M device hardened both by design and by operating conditions (MPP mode) with respect to the standard device TH 7863A. The irradiations were performed with "6"0Co or X-ray (10 keV) sources on devices in operating mode. (author). 3 refs., 8 figs.
Color recognition system for urine analyzer
In order to increase the speed of photoelectric conversion, a linear CCD is applied as the photoelectric converter instead of the traditional photodiode. A white LED is used as the light source of the system. The color information of the urine test strip is transferred into the CCD through a reflecting optical system. It is then converted to digital signals by an A/D converter. The test results of urine analysis are obtained by a data processing system. An ARM microprocessor is selected as the CPU of the system and a CPLD is employed to provide a driving timing for the CCD drive and the A/D converter. Active HDL7.2 and Verilog HDL are used to simulate the driving timing of the CPLD. Experimental results show that the correctness rate of the test results is better than 90%. The system satisfies the requirements of the color information collection of urine analyzer.
2010-08-01
International heliophysical year and basic space science in West Asia
This paper summarizes the IHY and BSS activities in West Asia and their importance in many Arab countries, such as Algeria, Egypt, Iraq, Jordan, Kuwait, Qatar, Saudi Arabia, UAE, etc. BSS future plans for some of these countries are as follows: It is proposed by the astronomers from the Arabian Gulf Region to build the Gulf Observatory on top of Jabal Shams (2980 msl) which will have a 2-3 m optical telescope. Libya signed a contract with a French company for building an observatory which will have a 2-m optical robotic telescope. It is also proposed to rebuild the Iraqi National Astronomical Observatory (INAO) which was destroyed during the two wars. It is planned to build a 5-6 m optical telescope and a small solar telescope on the top of Korek mountain, which has excellent observing conditions.
2007-12-01
UK PubMed Central (United Kingdom)
We have used Western blot analysis and immunocytochemistry to determine the effect of dietary K intake on the expression of protein kinase C (PKC) isoforms in the kidney. Western blot has demonstrated...Full Text Available
2004-06-01
Ionizing radiation hardening procedure of CCD's
International Nuclear Information System (INIS)
The procedure of charge-coupled devices (CCD) are investigated by using MOS capacitors for enhancing their ionizing radiation tolerance. Authors have found that the gate oxidation temperature, thickness of SiO_2 gate insulator and high temperature processes after gate oxidation are crucial for determining the radiation tolerance of the devices, and proposed to decrease the thickness of gate insulator, perform gate oxidation at 1000 deg C by means of dry oxidation and minimize the number of high temperature procedure steps after gate oxidation. All stated above is a necessary preparation for priducing radiation hardened charge-coupled devices.
Development of high resolution imaging detectors for X-ray astronomy
Energy Technology Data Exchange (ETDEWEB)
High (spatial) resolution imaging detectors for X-ray astronomy were developed. Several prototype detectors built and their feasibility and baseline performance were assessed. Two of these detector types are proposed for investigations on the advanced X-ray astrophysics facility (AXAF). The readiness of a new X-ray imaging system, the charge coupled device (CCD) imaging specctrometer is outlined, and state of the art performance parameters for microchannel plate (MCP) and CCD detectors are measured. Laboratory facilities and procedures for coating MCP are developed general high resolution imagery systems are analyzed.
1985-03-01
Development of high resolution imaging detectors for X-ray astronomy
International Nuclear Information System (INIS)
High (spatial) resolution imaging detectors for X-ray astronomy were developed. Several prototype detectors built and their feasibility and baseline performance were assessed. Two of these detector types are proposed for investigations on the advanced X-ray astrophysics facility (AXAF). The readiness of a new X-ray imaging system, the charge coupled device (CCD) imaging specctrometer is outlined, and state of the art performance parameters for microchannel plate (MCP) and CCD detectors are measured. Laboratory facilities and procedures for coating MCP are developed general high resolution imagery systems are analyzed.
1985-01-01
Queen's discovery lauded by top scientific journal
A scientific breakthrough at Queen's University's Sudbury Neutrino Observatory has received major international recognition. The journal Science ranked the discovery that cracked the "neutrino problem" second, in the journal's top 10 scientific achievements of 2002 (1/2 page).
2002-01-01
Oil Leak from Damaged Well in Gulf of ... - NASA Earth Observatory
Apr 25, 2010... oil per day were leaking from an oil well in the Gulf of Mexico in late April, following an explosion at an offshore drilling rig on April 20, 2010. ...
Observatory: Cluster FM5 (Rumba) - SPASE Resource Description
Feb 7, 2011 ... The potentials of the spherical sensor and nearby conductors are controlled ... Incoming data are continuously monitored by algorithms in the software ... together with FM8 (Tango) by a Soyuz-Fregat rocket from Baikonur. ...
Energy Technology Data Exchange (ETDEWEB)
This review covers research done at Lawrence Livermore National Laboratory under DOE contract. Areas of research are as follows: star evolution supernovae, and nucleosynthesis; stellar atmospheres and winds; galaxies and interstellar space; and high-energy astrophysics.
1983-01-01
Energy Technology Data Exchange (ETDEWEB)
This review covers research done at Lawrence Livermore National Laboratory in the fields of astronomy and astrophysics. The research areas mentioned are as follows: star evolution, supernovae, and nucleosynthesis; stellar atmospheres and winds; galaxies and the interstellar medium; and high-energy astrophysics.
1984-01-01
Numerical Taxonomy of Some Bacteria Isolated from Antarctic and Tropical Seawaters1
UK PubMed Central (United Kingdom)
Pfister, Robert M. (Lamont Geological Observatory, Palisades, N.Y.), and Paul R. Burkholder. Numerical taxonomy of some bacteria isolated from Antarctic and tropical seawaters. J....Full Text Available
1965-10-01
APOD: January 25, 1997 - M51: The Whirlpool Galaxy
on the picture will download the highest resolution version available. M51: The Whirlpool Galaxy Credit: W. Keel (U. Alabama), 1.1-meter Hall Telescope, Lowell Observatory...
2011-10-07
APOD: December 18, 1995 - M51: The Whirlpool Galaxy
on the picture will download the highest resolution version available. M51: The Whirlpool Galaxy Credit: 1.1 Meter Hall Telescope, Lowell Observatory, Bill Keel (U. Alabama)...
2011-10-07
Coverage and large scale anisotropies estimation methods for the Pierre Auger Observatory
Energy Technology Data Exchange (ETDEWEB)
When searching for anisotropies in the arrival directions of Ultra High Energy Cosmic Rays, one must estimate the number of events expected in each direction of the sky in the case of a perfect isotropy. We present in this article a new method, developed for the Auger Observatory, based on a smooth estimate of the zenith angle distribution obtained from the data itself (which is essentially unchanged in the case of the presence of a large scale anisotropy pattern). We also study the sensitivity of several methods to detect large-scale anisotropies in the cosmic ray arrival direction distribution : Rayleigh analysis, dipole fitting and angular power spectrum estimation.
2005-07-01
A comparison of x-ray detectors for mouse CT imaging
International Nuclear Information System (INIS)
There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise ...
2004-12-07
The stellar content of central dominant galaxies. I. CCD surface photometry
International Nuclear Information System (INIS)
UBVRI CCD surface photometry and color gradients are presented for 10 central dominant galaxies (CDGs), comprising gE, D, and cD morphological types and covering the range of Bautz-Morgan cluster types. The mean magnitude of the color gradients to a radius of 20 kpc is in agreement with those found in recent CCD studies of bright ellipticals in Virgo. The size of the gradients are consistent with N-body model predictions in which these galaxies are formed or enhanced by merger events. Parameters such as ellipticity, position angle of the major axis, and deviation from ellipticity for eight single-nucleus CDGs are also given. All galaxies show large changes in ellipticity and position angle with radius, and can be considered similar to Kormendy's T3 class of galaxies, in which tidal effects on isophotal structure are very probable. Three out of eight single-nucleus CDGs, NGC 1399, NGC 6876 and IC 1860, show evidence of isochromal flattening ...
British Library Electronic Table of Contents (United Kingdom)
A stable BSA blocking poly(dimethylsiloxane) (PDMS) microchannel was prepared based on in situ synthesized PDMS-gold nanoparticles composite films. The modified microchip could successfully suppress protein adsorption. The assembly was followed by contact angle, charge-coupled device (CCD) imaging, electroosmotic flow (EOF) measurements and electrophoretic separation methods. Contact angle measurements revealed the coated surface was hydrophilic, water contact angle for coated chips was 45.2^o compared to a water contact angle for native PDMS chips of 88.5^o. The coated microchips exhibited reproducible and stable EOF behavior. With FITC-labeled myoglobin incubation in the coated channel, no fluorescence was observed with CCD image, and the protein exhibited good electrophoretic effect in ...
2010-01-01
Real time neutron radioscopy - trends and applications
International Nuclear Information System (INIS)
Real Time Radiography (RTR) finds extensive applications for inspection of objects on assembly lines for rapid inspection. A typical RTR widely used includes a image intensifier, CCD camera, image processor and high resolution TV monitor in addition to radiographic source. Image intensifiers used in X-radiography employ CsI as the input detector. With the increased use of neutrons as radiation source, real time neutron radiography is also being practised widely. Image intensifiers used in neutron radiography employ gadolinium as the input screen. The neutron image intensifier system at the authors laboratory essentially consists of a 9 inch Trifield image intensifier tube, motorised zoom lens, CCD camera and a high resolution TV monitor
2003-11-12
International Nuclear Information System (INIS)
The results of experiments received on the plasma focus (PF) device with energy stored equal 4 kJ are represented. Photos of the current plasma sheath (CPS), pre-pinch, sphere-like plasma formations are produced with help of the electron-optical converter contained a gated micro-channel plate (MCP) and the CCD-camera imaging system in the visible region. The redial velocity of the CPS is about 107 cm/s. Neon plasma electron density measured with help of the interferograms in the visible region and the spectra in the soft X-ray region is equals to 3?1018 cm-3. Electron temperature is equal to about 200 eV. Discharge integral photos were obtained with help of the soft X-ray pinhole camera. Pictures with 2 ?s resolution of the plasma luminescence above PF anode region were made by CCD-camera.
2006-01-01
Particle and X-ray damage in pn-CCDs
Energy Technology Data Exchange (ETDEWEB)
The fully depleted pn-junction charge coupled device (pn-CCD) has been developed as a detector for X-ray imaging and high-resolution spectroscopy for the X-ray satellite missions XMM and ABRIXAS. If the detector is exposed to a particle radiation environment, the energy resolution is degraded due to charge transfer losses and a dark current increase. In a first experiment, prototype devices were irradiated with 10 MeV protons. After completion of the detector development, the proton irradiation was repeated for a quantitative study of the radiation damage, relevant for the satellite missions. The irradiation test was extended by a 5.5 MeV {alpha}-particle and a 6 keV X-ray exposure of the pn-CCD, including the CAMEX preamplifier chip.
2000-01-11
Optimization of alkaline hydrolysis of paddy straw for ferulic acid extraction
British Library Electronic Table of Contents (United Kingdom)
Response Surface Methodology (RSM) via Central Composite Design (CCD) was used to optimize the alkaline hydrolysis of paddy straw to improve ferulic acid extraction. The parameters involved, namely temperature (^oC), concentration of NaOH (M) and duration of extraction (h) are screened by Full Factorial Studies (FFD). The result obtained from FFD was 0.518% (5.18mg/g). The interactions between each parameters involved were studied using Central Composite Design (CCD). Upon optimization, the percentage of ferulic acid improved from 0.518% to 0.817% (8.17mg/g). The optimum conditions obtained from this study are 125^oC, 3.90M, 2.30h for temperature, concentration of NaOH and extraction time, respectively. This result shows a significant improvement than the previous published work. Details o...
2011-01-01
A tomography system at the thermal neutron column of the ENEA Casaccia TRIGA reactor
Energy Technology Data Exchange (ETDEWEB)
The developed system is intended for use at a collimated thermal neutron beam with a flux of about 10{sup 6} n/cm{sup 2} s. The system works with a cooled CCD array (192 x 165 pixels) and an intensifier for light from a NE426 scintillator with traditional optical coupling. A fine mechanical regulation system allows an accurate positioning of the tomographer, also ensuring the alignment of the CCD array with the rotation and translation axes. The acquisition of 200 projections is carried out in about 30 min with a reconstruction time (40 min max) depending on the reconstruction-matrix order. Radiography and tomography of significant objects are illustrated. The reconstruction algorithm, including spatial and temporal inhomogeneity corrections and filters, was tested with good results for projections up to 512 x 512 pixels. (orig.)
2002-07-01
A tomography system at the thermal neutron column of the ENEA Casaccia TRIGA reactor
International Nuclear Information System (INIS)
The developed system is intended for use at a collimated thermal neutron beam with a flux of about 10"6 n/cm"2 s. The system works with a cooled CCD array (192 x 165 pixels) and an intensifier for light from a NE426 scintillator with traditional optical coupling. A fine mechanical regulation system allows an accurate positioning of the tomographer, also ensuring the alignment of the CCD array with the rotation and translation axes. The acquisition of 200 projections is carried out in about 30 min with a reconstruction time (40 min max) depending on the reconstruction-matrix order. Radiography and tomography of significant objects are illustrated. The reconstruction algorithm, including spatial and temporal inhomogeneity corrections and filters, was tested with good results for projections up to 512 x 512 pixels. (orig.)
Patterns of photometric and chromospheric variation among Sun-like stars: A 20-year perspective
We examine patterns of variation of 32 primarily main sequence stars, extending our previous 7-12 year time series to 13-20 years by combining b, y data from Lowell Observatory with similar data from Fairborn Observatory. Parallel chromospheric Ca II H and K emission data from the Mount Wilson Observatory span the entire interval. The extended data strengthen the relationship between chromospheric and photometric variation derived previously. Twenty-seven stars are deemed variable. On a year-to-year timescale young active stars become fainter when their Ca II emission increases while older less active stars such as the Sun become brighter when their Ca II emission increases. The Sun's total irradiance variation, scaled to the b and y filter photometry, still appears to be somewhat smaller than stars in our limited sample with similar mean chromospheric activity, but we now regard this discrepancy as probably due mainly to ...
2007-01-01
The kinematics of coronal mass ejections using multiscale methods
The diffuse morphology and transient nature of coronal mass ejections (CMEs) make them difficult to identify and track using traditional image processing techniques. We apply multiscale methods to enhance the visibility of the faint CME front. This enables an ellipse characterisation to objectively study the changing morphology and kinematics of a sample of events imaged by the Large Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) and the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) onboard the Solar Terrestrial Relations Observatory (STEREO). The accuracy of these methods allows us to test the CMEs for non-constant acceleration and expansion. We exploit the multiscale nature of CMEs to extract structure with a multiscale decomposition, akin to a Canny edge detector. Spatio-temporal filtering highlights the CME front as it propagates in time. We apply an ellipse ...
2009-01-01
Energy Technology Data Exchange (ETDEWEB)
The purpose of this experiment was to evaluate the diagnostic ability of a CCD-based digital system (CDX-2000HQ) in the detection of incipient dental caries. 93 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were radiographed using 4 imaging methods. Automatically processed No.2 Insight film (Eastman Kodak Co., U.S.A.) was used for conventional radiography, scanned images of conventional radiograms for indirect digital radiography were used. For the direct digital radiography, the CDX-2000HQ CCD system (Biomedisys Co. Korea) was used. The subtraction images were made from two direct digital images by Sunny program in the CDX-2000HQ system. Two radiologists and three endodontists examined the presence of lesions using a five-point confidence scale and compared the diagnostic ability by ROC (Receiver Operating Characteristic) analysis and one way ANOVA test. The mean ROC areas of conventional radiography, ...
2003-03-15
International Nuclear Information System (INIS)
The purpose of this experiment was to evaluate the diagnostic ability of a CCD-based digital system (CDX-2000HQ) in the detection of incipient dental caries. 93 extracted human teeth with sound proximal surfaces and interproximal artificial cavities were radiographed using 4 imaging methods. Automatically processed No.2 Insight film (Eastman Kodak Co., U.S.A.) was used for conventional radiography, scanned images of conventional radiograms for indirect digital radiography were used. For the direct digital radiography, the CDX-2000HQ CCD system (Biomedisys Co. Korea) was used. The subtraction images were made from two direct digital images by Sunny program in the CDX-2000HQ system. Two radiologists and three endodontists examined the presence of lesions using a five-point confidence scale and compared the diagnostic ability by ROC (Receiver Operating Characteristic) analysis and one way ANOVA test. The mean ROC areas of conventional radiography, ...
2003-03-01
A Brief History of Astronomical Brightness Determination Methods at Optical Wavelengths
In this brief article I review the history of astronomical photometry, touching on observations made by the ancient Chinese, Hipparchus and Ptolemy, the development of the concept (and definition) of magnitude, the endeavors of Argelander and Zoellner, work at Harvard at the end of the 19th century, and the development of photography, photomultipliers, and CCD's and their application to astronomy.
2001-01-01
Search for TeV Counterparts in $\\gamma$-Ray Bursts
Based on BACODINE network notification the Whipple Observatory gamma-ray telescope has been used to search for the delayed TeV counterpart to BATSE-detected gamma-ray bursts. In the fast slew mode, any point in the sky can be reached within two minutes of the burst notification. The search strategy, necessary because of the uncertainty in burst position and limited FOV of the camera, is described.
1997-01-01
Physics of thermal gaseous nebulae
Energy Technology Data Exchange (ETDEWEB)
Much of the material presented in this book derived originally from the series ''Physical Processes in Gaseous Nebulae'' initiated at the Harvard College Observatory in the 1930's. The subject of gaseous nebulae, which offers opportunities for studies of stellar evolution, should be of interest to atomic physicists, spectroscopists, plasma experts, and to observers and theoreticians alike for the study of attenuated ionized gases.
1984-01-01
New Protocol is 50th anniversary gift to CERN
"Nine of CERN 's 20 Member States today a signed new Protocol on privileges and immunities. This brings the Organization into line with other European intergovernmental organizations, such as the European Space Agency and the European Southern Observatory, which already enjoy international status in all of their Member States" (2
2004-01-01
MicroDiffraction in the Scanning Electron Microscope (SEM)
The identification of crystallographic phases in the scanning electron microscope (SEM) has been limited by the lack of a simple way to obtain electron diffraction data of an unknown while observing the micro structure of the specimen. With the development of Charge Coupled Device (CCD) based detectors, backscattered electron Kikuchi patterns (BEKP), alternately referred to as electron backscattered diffraction patterns (EBSP), can be easily collected. Previously, BEKP has been limited to crystallographic orientation studies due to the poor pattern quality collected with video rate detector systems. With CCD detectors, a typical BEKP can now be acquired from a micron or sub-micron-sized crystal using an exposure time of 1-10 seconds with an accelerating voltage of 10-40 kV and a beam current as low as 0.1 nA. Crystallographic phase analysis using BEKP is unique in that the properly equipped SEM permits high magnification images, BEKP`s, and ...
1997-12-31
Camera for coherent diffractive imaging and holography with a soft-x-ray free-electron laser
International Nuclear Information System (INIS)
We describe a camera to record coherent scattering patterns with a soft-x-ray free-electron laser (FEL). The camera consists of a laterally graded multilayer mirror, which reflects the diffraction pattern onto a CCD detector. The mirror acts as a bandpass filter for both the wavelength and the angle, which isolates the desired scattering pattern from nonsample scattering or incoherent emission from the sample. The mirror also solves the particular problem of the extreme intensity of the FEL pulses, which are focused to greater than 10"1"4 W/cm"2. The strong undiffracted pulse passes through a hole in the mirror and propagates onto a beam dump at a distance behind the instrument rather than interacting with a beam stop placed near the CCD. The camera concept is extendable for the full range of the fundamental wavelength of the free electron laser in Hamburg (FLASH) FEL (i.e., between 6 and 60 nm) and into the water window. We have fabricated and ...
2008-04-01
Remote sensing of the atmosphere by resonance Raman LIDAR
Energy Technology Data Exchange (ETDEWEB)
When in resonance, Raman scattering exhibits strong enhancement ranging from four to six orders of magnitude. This physical phenomenon has been applied to remote sensing of the Earth`s atmosphere. With a 16 inch Cassegrain telescope and spectrometer/ CCD-detector system, 70-150 ppm-m of SO{sub 2} in the atmosphere has been detected at a distance of 0.5 kilometer. This system can be used to detect/monitor chemical effluence in the atmosphere by their unique Raman fingerprints. Experimental result together with detailed resonance Raman and atmospheric laser propagation effects will be discussed.
1994-12-01
British Library Electronic Table of Contents (United Kingdom)
The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.
2010-01-01
Low cost, low power, high sensitivity, real time neutron detection microsystem
International Nuclear Information System (INIS)
A Si array neutron detector is proposed based on commercial CCD and CMOS sensor technology coupled with a thin film neutron conversion coating. System sensitivity is estimated for a baseline device containing a single array and various schemes to increase detection probability by simple area scaling and stacking are discussed. Some possible use scenarios are discussed involving static and moving sources. Likely neutron source fluxes for weapons grade and commercial grade nuclear material are estimated along with expected intensities of cosmic background neutrons which would establish a noise floor to detection limits.
2002-10-10
Laser ray-tracing method for optical testing.
We have developed a novel laser ray-tracing method to measure aberrations in optical systems. It consists of delivering narrow laser pencils (by a laser scanner), recording the spots that are formed on the image plane (with a CCD camera), and computing the position of each centroid. This approach could be considered an experimental (approximate) implementation of standard numerical ray tracing. Several tests and experiments, including a direct comparison with a Hartmann-Shack wave-front sensor, provided highly satisfactory results that confirmed the validity of the method and revealed potential advantages. PMID:18073906
1999-07-15
International Nuclear Information System (INIS)
The aim of this work is the implantation and characterization of a neutron radiography system that uses an electronic device for attainment of images in real time, for its implementation in the nuclear research reactor Argonauta at IEN/CNEN (Nuclear Engineering Institute of the Brazilian Nuclear Energy Commission). The Electronic Imaging System in Real Time is composed by a scintillator screen for neutron, a video camera (CCD), a digital plate and a computer with specific computational programs for digital processing of the images. The System in installed real time is apt to carry through neutron radiography inspections of static and dynamic events of several types of samples. (author)
2004-04-01
Cores of early-type galaxies - the nature of dwarf spheroidal galaxies
International Nuclear Information System (INIS)
The characteristics and evolution of dwarf spheroidal galaxies (DSGs) are modeled on the basis of high-resolution CCD photometry obtained with the Canada-France-Hawaii telescope and reported by Kormendy (1986). The data and the results of core-parameter correlation studies are presented in extensive graphs and discussed. It is inferred that at least some DSGs are formed by the stripping of gas from dwarf spiral and irregular galaxies, although internal gas processes may also be important. The hypothesis that DSGs represent the faint end of the elliptical-galaxy sequence appears to be ruled out. 50 references.
Application of neutron radiography to a diagnosis of refrigerator
International Nuclear Information System (INIS)
A diagnosis of the refrigerant flows in a refrigerator was carried out by real-time neutron radiography. The thermal neutron radiography system of JRR-3M in Japan Atomic Energy Research Institute and the real-time image processing system developed by Musashi Institute of Technology were used. Freon evaporating flows in the evaporator, condensing flows in the condenser, flashing flows in the capillary tube and flows in the accumulator were visualized and the dynamic behaviors under practical conditions were clarified. In the case of the capillary tube of 0.8 mm i.d., a cooled-CCD camera was utilized. (orig.).
1996-07-01
Quantitative imaging of turbulent and reacting flows
Energy Technology Data Exchange (ETDEWEB)
Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide ...
1993-12-01
Through the collaborative efforts of undergraduates and faculty at Gettysburg and Franklin & Marshall Colleges, we present the compilation of 10 years of differential photometry for three K-type stars in the Pleiades. These young stars have rotational light curves with V-band amplitudes of a few percent (10% in the most active) due to BY Draconis-type behavior (modulation due to rotation of a star with non-uniform surface brightness). With 10 years of photometry reduced, measured, and compiled we are now in a position to probe the V-band variations in these stars for indications of the extent of brightness asymmetry in the photosphere, and characteristics of the long-term activity of these stars. These observations were acquired at the National Undergraduate Research Observatory, operated by Lowell Observatory and Northern Arizona University. This work is supported by Gettysburg College, the Pennsylvania Space Grant Consortium, Arizona ...
2007-05-01
During searches for new optical Galactic supernova remnants (SNRs) in the high resolution, high sensitivity Anglo-Australian Observatory/United Kingdom Schmidt Telescope (AAO/UKST) HAlpha survey of the southern Galactic plane, we uncovered a variety of filamentary and more diffuse, extensive nebular structures in the vicinity of Wolf-Rayet (WR) star 48 (Theta Muscae), only some of which were previously recognised. We used the double-beam spectrograph of the Mount Stromlo and Siding Spring Observatory (MSSSO) 2.3-m to obtain low and mid resolution spectra of selected new filaments and structures in this region. Despite spectral similarities between the optical spectra of WR star shells and SNRs, a careful assessment of the new spectral and morphological evidence from our deep HAlpha imagery suggests that the putative shell of Theta Mus is not a WR shell at all, as has been commonly accepted, but is rather part of a more complex area of ...
2009-01-01
Energy Technology Data Exchange (ETDEWEB)
During the past few years, the dual role that ozone plays in climate change has been becoming increasingly obvious. First, continuous thinning of the ozone layer has been evident, even in the high and middle latitudes in the northern hemisphere. Secondly, ozone is also a greenhouse gas, affecting radiative transfer. Increases in tropospheric ozone have a positive forcing, whereas decreases in stratospheric ozone cause a negative forcing. During the last six years, measurements on total ozone and the vertical distribution of ozone have been performed at the Sodankylae Observatory. At Jokioinen Observatory, measurements on total ozone have been performed since 1990 and measurements on the vertical distribution of ozone since 1993. The overall project has focused on extending the national data series on total ozone and the vertical distribution of ozone. At the same time, the study has contributed to the study of interannual variability of the ...
1996-12-31
International Nuclear Information System (INIS)
We present 14 years of contemporaneous photometric and spectroscopic observations of 28 solar analog stars, taken with the Tennessee State University Automatic Photometric Telescopes at Fairborn Observatory and the Solar-Stellar Spectrograph at Lowell Observatory. These are the best observed and most nearly Sun-like of the targets in our magnitude-limited (V #<=# 7.5) sample. The correlations between luminosity and activity reveal the expected inverse activity-brightness correlations for active stars. Strong direct correlations between activity and brightness are not prevalent for the less active solar age stars, but are precision limited. The Sun does not appear to have unusually low photometric variability when compared with the most Sun-like inactive solar analogs. We present evidence that the activity index R'_H_K is not a good discriminant of Maunder Minimum candidate stars. On the basis of a star that appears to have transitioned from ...
2009-07-01
Optical Turbulence Measurements and Models for Mount John University Observatory
Site measurements were collected at Mount John University Observatory in 2005 and 2007 using a purpose-built scintillation detection and ranging system. $C_n^2(h)$ profiling indicates a weak layer located at 12 - 14 km above sea level and strong low altitude turbulence extending up to 5 km. During calm weather conditions, an additional layer was detected at 6 - 8 km above sea level. $V(h)$ profiling suggests that tropopause layer velocities are nominally 12 - 30 m/s, and near-ground velocities range between 2 -- 20 m/s, dependent on weather. Little seasonal variation was detected in either $C_n^2(h)$ and $V(h)$ profiles. The average coherence length, $r_0$, was found to be $7 \\pm 1$ cm for the full profile at a wavelength of 589 nm. The average isoplanatic angle, $\\theta_0$, was $1.0 \\pm 0.1$ arcsec. The mean turbulence altitude, $\\bar{h_0}$, was found to be $2.0\\pm0.7$ km above sea level. No average in the Greenwood frequency, $f_G$, could be established due ...
2010-01-01
International Nuclear Information System (INIS)
The proposed Sudbury Neutrino Observatory is based on a Cherenkov detector which has a total of 1000 tonne of heavy water and 1800 tonne of light water for its sensitive volume. The detector is optimized for the measurement of extra-terrestrial low energy electron neutrinos and electron antineutrinos spectra as well as the total neutrino flux independent of neutrino flavours. It will delineate the Standard Solar Model and neutrino propagation aspects of the solar neutrino problem, provide detailed information on the dynamics of stellar collapse and measure neutrino masses and oscillation parameters with high sensitivity.
Star Formation in the Outer Disks of Spiral Galaxies
This is a study done in collaboration with Deidre Hunter at Lowell Observatory studying star formation in two luminous spiral galaxies NGC 801 and UGC 2885. We used ultra-deep H? images taken at the KPNO 2.1 m telescope. We compare these data to stellar images at various wavelengths and to HI maps to determine the extent of star formation activity into the outer disk in these galaxies and its relationship to the gas and older stars. TW is grateful for an REU internship during the summer of 2010 at Northern Arizona University, funded by NSF through grant AST-1004107.
2011-01-01
ROSAT observations of the RSCVn binary sigma Geminorum
DEFF Research Database (Denmark)
X-ray observations of the RSCVn system sigma Geminorum have been undertaken with the ROSAT observatory. Several spectra of very good signal-to-noise ratio were obtained. Spectral fitting using metal abundances amounting to 50% of solar values reveal two temperature components at 2 MK and 12 MK. Previous EXOSAT observations showed another component at 40 MK. Particular interest is focused on the temporal variations of the X-ray emission. It is found that variations occur on time scales ranging from years to hours and minutes.
1997-01-01
High altitude wind velocity at San Pedro Martir and Mauna Kea
We analyze the monthly average wind velocity at about 12 km above sea level, between 1980 to 1995, for San Pedro Martir, Mauna Kea, another existing observatorie and some sites of interest. We compare the results obtained from two different data sets, the GGUAS and NCEP. Our results show that San Pedro Martir and Mauna Kea are comparable and are amongst the most suitable sites to apply slow wavefront corrugation correction techniques
2003-01-01
Heliophysics Event Knowledgebase for the Solar Dynamics Observatory and Beyond
The immense volume of data generated by the suite of instruments on SDO requires new tools for efficient identifying and accessing data that is most relevant to research investigations. We have developed the Heliophysics Events Knowledgebase (HEK) to fill this need. The HEK system combines automated data mining using feature-detection methods and high-performance visualization systems for data markup. In addition, web services and clients are provided for searching the resulting metadata, reviewing results, and efficiently accessing the data. We review these components and present examples of their use with SDO data.
2010-01-01
Emission Line Spectra in the Soft X-Ray Region 20-75 (Angstrom)
Energy Technology Data Exchange (ETDEWEB)
As part of a project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, we studied emission lines of argon and sulfur in the soft X-ray and extreme ultraviolet region. Here we present observations of Ar IX through Ar XVI and S VII through S XIV between 20 and 75 {angstrom} to illustrate our work.
2002-06-18
International Nuclear Information System (INIS)
The refrigerant two-phase flows in a capillary tube and a distributor used in a compression-type refrigerator were visualized by real-time neutron radiography. The thermal neutron radiography system of JRR-3M at the Japan Atomic Energy Research Institute was used. In the visualization experiments of the two-phase flow in the capillary tube of 2 mm I.D., a cooled CCD camera was used, and the axial one-dimensional distributions of void fraction were measured. For the distributor, a high sensitivity video camera with a silicone intensified target tube was used. From the visualized images, the refrigerant behaviors in the distributor were clearly shown, and the liquid fraction in each tube was measured. As a result, it was shown that the refrigerant behaviors in the distributor effected the distributing performance of the refrigerant flow.
1999-11-03
British Library Electronic Table of Contents (United Kingdom)
In this study, a two-step process was developed to produce biodiesel from Calophyllum inophyllum oil. Pre-treatment with phosphoric acid modified b-zeolite in acid catalyzed esterification process preceded by transesterification which was done using conventional alkali catalyst potassium hydroxide (KOH). The objective of this study is to investigate the relationship between the reaction temperatures, reaction time and methanol to oil molar ratio in the pre-treatment step. Central Composite Design (CCD) and Response Surface Methodology (RSM) were utilized to determine the best operating condition for the pre-treatment step. Biodiesel produced by this process was tested for its fuel properties.
2011-01-01
Spray, combustion, and heat transfer studies in a Ricardo hydra direct-injection diesel engine
Energy Technology Data Exchange (ETDEWEB)
The spray and combustion development in a single-cylinder, direct-injection diesel engine equipped with optical access was examined using a number of complementary techniques. A laser imaging system, based around a pulsed copper-vapour laser synchronised to an intensified CCD camera, was used to obtain images of the four fuel sprays prior to combustion, and to determine the tip penetration of each spray as a function of crankangle. The surface heat flux to the wall of the piston bowl was measured by placing a fast-response thermocouple at the impingement point of one of the sprays, and a two-colour imaging system was used to obtain digital images of the flame temperature and equivalent soot distribution in the cylinder. (author)
1996-12-31
Sejong Open Cluster Survey. I. NGC 2353
UBVI CCD photometry of NGC 2353 is obtained as part of the "Sejong Open cluster Survey" (SOS). Using the photometric membership criteria we selelct probable members of the cluster. We derive the reddening and distance to the cluster, i.e. E(B-V) = 0.10 +/- 0.02 mag and 1.17 +/- 0.04 kpc, respectively. We find that the projected distribution of the probable members on the sky is elliptical in shape rather than circular. The age of the cluster is estimated to be log(age)=8.1 +/- 0.1, older than what was found in previous studies. The minimum value of binary fraction is estimated to be about 48 +/- 5 percent from a Gaussian function fit to the distribution of the distance moduli of the photometric members. Finally, we also obtain the luminosity function and the initial mass function (IMF). The slope of the IMF is Gamma = -1.3 +/- 0.2.
2011-01-01
Rapid optical variability of TeV blazars
British Library Electronic Table of Contents (United Kingdom)
Abstract In this first systematic attempt to characterize the intranight optical variability (INOV) of TeV-detected blazars, we have monitored a well-defined set of nine TeV blazars on total 26 nights during 2004-10. In this R- or V-band-monitoring programme only one blazar was monitored per night and the minimum duration was close to 4-h, the average being 5.3 h per night. Using the CCD for strictly simultaneous photometry of the blazar and nearby reference stars (N-star photometry), an INOV detection threshold of -1-2-per cent was achieved in the densely sampled differential light curves derived from our data. We have further expanded the sample by including another 13 TeV blazars, taking advantage of the availability in the literature of INOV data, including those published earlier in o...
2011-01-01
International Nuclear Information System (INIS)
An imaging position sensitive detector for charged particles, neutrons, X-and gamma rays has been developed. The novel feature of this scintillation imaging radiation detector is its ability to detect individual nuclear particle scintillations with a h igh degree of spatial resolution. The key elements of this detector system are a high gain, low noise image intensifier tube, a CCD camera and commercially available image processing hardware and software. This detector system is highly effective for applications such as low fluence and real time neutron radiography, mapping of radioactive contamination in nuclear reactor fuel rods, X-ray diffraction imaging, high speed autoradiography and in general position sensitive detection of nuclear radiation. Results of some of the exploratory experiments carried out using this detector system are presented in this paper. (orig.).
1996-01-01
Ovis aries CR4 is involved in Mannheimia haemolytica leukotoxin-induced cytotoxicity
British Library Electronic Table of Contents (United Kingdom)
Pneumonia caused by Mannheimia haemolytica is an important disease of domestic sheep (DS, Ovis aries) and cattle (BO). M. haemolytica is a normal commensal of the upper respiratory tract in ruminants, but during stress and viral infection it breaches the host innate mucosal defense and descents into lungs causing fibrinous pleuropneumonia. Leukotoxin (Lkt) produced by M. haemolytica is cytolytic to all subsets of ruminant leukocytes. Earlier, we and others have shown that DS and BO LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) can mediate Lkt-induced cytolysis. It is not clear whether CR4 (CD11c/CD18), which is involved in chemotaxis, phagocytosis and regulates host immune response can also mediate Lkt-induced cytolysis in ruminants. The host innate immune response to M. haemolytica is poorly ...
2010-01-01
Mismatch measurement and correction tools for the PS-SPS transfer of the 26GeV/C LHC beam
TRANSVERSE EMITTANCE PRESERVATION IS A MAJOR CONCERN OF THE LHC INJECTOR CHAIN. MINIMISATION OF THE BLOW-UP DUE TO MISMATCH AT INJECTION INTO THE SPS IS THEREFORE MANDATORY. WHILE THE TRANSVERSE POSITIONN OF THE BEAM IN THE SPS INJECTION LINE IS MONITORED BUNCH BY BUNCH BY AN OTR (OPTICAL TRANSITION RADIATION) SCREEN AND A FAST CCD (CHARGED COUPLED DEVICE) CAMERA, THE PHASE SPACE MATCHING AT INJECTION IS MONITORED BY AN OTR BASED MISMATCH MONITOR IN THE SPS RING. ORTHOGONAL TUNING KNOBS WERE DEVELOPED TO TUNE INDEPENDENTLY TWISS PARAMETERS, DISPERSION AND DISPERSION DERIVATIVE. IN THIS PAPER WE DESCRIBE THE MISMATCH CORRECTION MECHANISM AS WELL AS THE TWO MONITORING SYSTEMS. WE REPORT ON FIRST MEASUREMENTS WHICH WERE CARRIED OUT DURING THE 1998 SPS RUN.
1999-01-01
Ionized gas and radio emission in the barred Seyfert galaxy NGC 5728
International Nuclear Information System (INIS)
This paper reports extensive new optical and radio observations of NGC 5728, emphasizing the central regions. Deep photographs revealing detail in the faint spiral arms are briefly discussed. Broad-band UBV CCD images obtained to examine the colors of the stellar populations that comprise the bar and central ring are presented. The velocity field and emission maps obtained from imaging spectroscopic measurements in the H-alpha emission line are discussed. Conventional long-slit spectra covering the ionized gas in the nuclear region are described. Detailed maps of the radio emission in the central regions of NGC 5728 are presented. These combined data provide considerable evidence for the inflow of gas into the nuclear region, in response to the nonaxisymmetric gravitational potential of the bar. The possible relation of this phenomenon to the Seyfert nature of NGC 5728 is also considered. 48 references.
Energy Technology Data Exchange (ETDEWEB)
The aim of this work is the implantation and characterization of a neutron radiography system that uses an electronic device for attainment of images in real time, for its implementation in the nuclear research reactor Argonauta at IEN/CNEN (Nuclear Engineering Institute of the Brazilian Nuclear Energy Commission). The Electronic Imaging System in Real Time is composed by a scintillator screen for neutron, a video camera (CCD), a digital plate and a computer with specific computational programs for digital processing of the images. The System in installed real time is apt to carry through neutron radiography inspections of static and dynamic events of several types of samples. (author)
2004-04-15
Groundtruth approach to accurate quantitation of fluorescence microarrays
Energy Technology Data Exchange (ETDEWEB)
To more accurately measure fluorescent signals from microarrays, we calibrated our acquisition and analysis systems by using groundtruth samples comprised of known quantities of red and green gene-specific DNA probes hybridized to cDNA targets. We imaged the slides with a full-field, white light CCD imager and analyzed them with our custom analysis software. Here we compare, for multiple genes, results obtained with and without preprocessing (alignment, color crosstalk compensation, dark field subtraction, and integration time). We also evaluate the accuracy of various image processing and analysis techniques (background subtraction, segmentation, quantitation and normalization). This methodology calibrates and validates our system for accurate quantitative measurement of microarrays. Specifically, we show that preprocessing the images produces results significantly closer to the known ground-truth for these samples.
2000-12-01
British Library Electronic Table of Contents (United Kingdom)
Objective:EEG source imaging provides important information regarding the underlying neural activity from noninvasive electrophysiological measurements. The aim of the present study was to evaluate source reconstruction techniques by means of the intracranial electrocorticograms (ECoGs) and functional MRI.Methods:Five source imaging algorithms, including the minimum norm least square (MNLS), LORETA with Lp-norm (p equal to 1, 1.5 and 2), sLORETA, the minimum Lp-norm (p equal to 1 and 1.5; when p=2, the MNLS method is mathematically equivalent to the minimum Lp-norm) and L1-norm (the linear programming) methods, were evaluated in a group of 10 human subjects, in a paradigm with somatosensory stimulation. Cortical current density (CCD) distributions were estimated from the scalp somatosensor...
2007-01-01
Enhancement of bioleaching of a spent Ni/Mo hydroprocessing catalyst by Penicillium simplicissimum
British Library Electronic Table of Contents (United Kingdom)
Statistically based experimental designs were applied to screen and optimize the bioleaching of spent hydrocracking catalyst by Penicillium simplicissimum. Eleven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design. Four significant variables (pulp density, sucrose, NaNO"3, and yeast extract concentrations) were selected for the optimization studies. The combined effect of these variables on metal bioleaching was studied using a central composite design (CCD). Second-order polynomials were established to identify the relationship between the recovery percent of the metals and the four significant variables. The optimal values of the variables for maximum metals bioleaching were as follows: pulp density (4.0%, w/v), sucrose (90g/L), NaNO"3 (2...
2011-01-01
British Library Electronic Table of Contents (United Kingdom)
BACKGROUND: High levels of g-aminobutyric acid (GABA) accumulate in plant tissues under various stresses. GABA accumulation is also influenced by cultivar. This aim of this study was to select the most promising cultivar of fava bean for GABA accumulation and to optimise the culture conditions for GABA production in germinated fava beans by response surface methodology based on central composite design (CCD). RESULTS: GABA content and glutamate decarboxylase activity in germinated seeds of cultivar S2 were significantly higher than those in other cultivars (P < 0.05). A significant negative correlation (r = -0.765, P < 0.05) between germination percentage and 1000-kernel weight was observed. There was a linear relationship between GABA content and sprout length (R2 = 0.816). The regression...
2010-01-01
A six-axes robot for deep water applications
Energy Technology Data Exchange (ETDEWEB)
The six-axes industrial robot MANUTEC r15 UW was modified to work underwater and successfully tested down to the simulated water depth of 1100 m. Next step in the program was to use this robot as a handling tool for inspection tasks at the welding seam of an underwater structure conducted with CCD-cameras and distance sensors. This was also to demonstrate the possibility to assist and later on to replace divers from this work. Additional research was focussed on the stiffness and rigidity of the robot during the precise guiding of tools and workpieces under current water conditions up to a flow velocity of 1.1 m/s. Present work is concentrated on the application of this subsea robot on a maintenance task at the Brazilian underwater template OCTOS-1000. For this experiments the robot is integrated in a large mock-up which simulates a quarter section of this template. (orig.)
1994-01-01
We present mid-infrared spectro-imagery and high-resolution spectroscopy ofthe Orion bar and of a region in the Orion nebula. These observations have beenobtained in the Guaranteed Time with the Circular Variable Filters of the ISOcamera (CAM-CVF) and with the Short Wavelength Spectrometer (SWS), on board theEuropean Infrared Space Observatory (ISO). Our data shows emission fromamorphous silicate grains from the entire HII region and around the isolatedO9.5V star Theta2 Ori A. The observed spectra can be reproduced by a mixture ofinterstellar silicate and carbon grains heated by the radiation of the hotstars present in the region. Crystalline silicates are also observed in theOrion nebula and suspected around Theta2 Ori A. They are probably ofinterstellar origin. The ionization structure and the distribution of thecarriers of the Aromatic Infrared Bands (AIBs) are briefly discussed on thebasis of the ISO observations.
2000-01-01
Mining Knowledge in Astrophysical Massive Data Sets
Modern scientific data mainly consist of huge datasets gathered by a very large number of techniques and stored in very diversified and often incompatible data repositories. More in general, in the e-science environment, it is considered as a critical and urgent requirement to integrate services across distributed, heterogeneous, dynamic "virtual organizations" formed by different resources within a single enterprise. In the last decade, Astronomy has become an immensely data rich field due to the evolution of detectors (plates to digital to mosaics), telescopes and space instruments. The Virtual Observatory approach consists into the federation under common standards of all astronomical archives available worldwide, as well as data analysis, data mining and data exploration applications. The main drive behind such effort being that once the infrastructure will be completed, it will allow a new type of multi-wavelength, multi-epoch science which can only be barely ...
2010-01-01
Cosmological Questions for the European Southern Observatory Very Large Telescope
The next decade promises an observational revolution which will change cosmology forever. The precise measurement of the angular anisotropy of the cosmic microwave background should specify to a few percent all of the parameters of the cosmological model which effect astrophysics. The growth of structure will then be determined (but not yet observed) until gravitational collapse becomes highly non-linear and stars, galaxies and active galactic nuclei (AGN) form. These processes are hard to model with basic physics because they are complex and allow a rich variety of expression. Instead observations will determine when the first stars and quasars formed, and how and when galaxies assembled. If we can reconcile the numerous contradictions which characterize the subject today, cosmology will become a mature subject, founded on the agreement between detailed, inclusive and realistic models, which make precise predictions, and the wealth of new data which will come from a wide variety of ...
1996-01-01
Real-time neutron radiography at Texas A and M University
Energy Technology Data Exchange (ETDEWEB)
A real-time neutron radiography imaging system has been installed at the Texas A and M University Nuclear Science Center. The system employs a scintillating screen viewed by a low-light TV camera with a front surface mirror placed at 45deg to the neutron beam. The key components of the system are the neutron camera and the image capture and processing unit. The neutron camera uses an NE 426 scintillating screen (ZnS), front surface mirror, remote focus and zoom lens, intensified relay optics (IRO) and monochrome CCD television camera. The image capture and processing unit consists of an IBM PC AT-compatible computer, arithmetic frame grabber, frame processor and high-resolution color monitor. The neutron camera is similar to others using a silicon intensified target (SIT) television camera to provide a TV image of the low-level light from a NE 426 screen. The IRO and CCD camera are used in place of the SIT camera. The computer digitizes the TV ...
1990-12-20
Real-time neutron radiography at Texas A and M University
International Nuclear Information System (INIS)
A real-time neutron radiography imaging system has been installed at the Texas A and M University Nuclear Science Center. The system employs a scintillating screen viewed by a low-light TV camera with a front surface mirror placed at 45deg to the neutron beam. The key components of the system are the neutron camera and the image capture and processing unit. The neutron camera uses an NE 426 scintillating screen (ZnS), front surface mirror, remote focus and zoom lens, intensified relay optics (IRO) and monochrome CCD television camera. The image capture and processing unit consists of an IBM PC AT-compatible computer, arithmetic frame grabber, frame processor and high-resolution color monitor. The neutron camera is similar to others using a silicon intensified target (SIT) television camera to provide a TV image of the low-level light from a NE 426 screen. The IRO and CCD camera are used in place of the SIT camera. The computer digitizes the TV ...
1990-12-01
Energy Technology Data Exchange (ETDEWEB)
This paper bundles 40 contributions by the IceCube collaboration that were submitted to the 30th International Cosmic Ray Conference ICRC 2007. The articles cover studies on cosmic rays and atmospheric neutrinos, searches for non-localized, extraterrestrial {nu}{sub e}, {nu}{sub {mu}} and {nu}{sub {tau}} signals, scans for steady and intermittent neutrino point sources, searches for dark matter candidates, magnetic monopoles and other exotic particles, improvements in analysis techniques, as well as future detector extensions. The IceCube observatory will be finalized in 2011 to form a cubic-kilometer ice-Cherenkov detector at the location of the geographic South Pole. At the present state of construction, IceCube consists of 52 paired IceTop surface tanks and 22 IceCube strings with a total of 1426 Digital Optical Modules deployed at depths up to 2350 m. The observatory also integrates the 19 string AMANDA subdetector, that was completed in ...
2007-11-02
Energy Technology Data Exchange (ETDEWEB)
Sulfuric acid and its partially or completely neutralized salts with ammonia are believed to result from the oxidation of sulfur dioxide in cloud water and in other heterogeneous media present in the atmosphere. Due to the natural abundance of ammonia and the ubiquitous presence of sulfur in the atmosphere, (NH/sub 4/)/sub 2/SO/sub 4/ is commonly the dominant chemical species in the ambient aerosol. The amounts of ammonium sulfates are expected to be very low in areas far removed from anthropogenic emissions of sulfur dioxide. The chemical composition of submicrometer aerosol particles was determined at the Mauna Loa Observatory (MLO) on Mauna Loa in Hawaii during an eight-day period in August 1986. The MLO site was selected for this measurement because it is the only ground-based aerosol observatory in the remote Pacific Ocean that allows extended sampling of aerosols in the free troposphere. Measurements were made using an attenuated total ...
1988-01-01
HALO - the helium and lead observatory for supernova neutrinos
Energy Technology Data Exchange (ETDEWEB)
The Helium and Lead Observatory (HALO) is a supernova neutrino detector under development for construction at SNOLAB. It is intended to fulfill a niche as a long term, low cost, high livetime, and low maintenance, dedicated supernova detector. It will be constructed from 80 tonnes of lead, from the decommissioning of the Deep River Cosmic Ray Station, and instrumented with approximately 384 meters of {sup 3}He neutron detectors from the final phase of the SNO experiment. Charged- and Neutral-Current neutrino interactions in lead expel neutrons from the lead nuclei making a burst of detected neutrons the signature for the detection of a supernova. Existing neutrino detectors are mostly of the water Cerenkov and liquid scintillator types, which are primarily sensitive to electron anti-neutrinos via charged-current interactions on the hydrogen nuclei in these materials. By contrast, the large neutron excess of a heavy nucleus like Pb acts to Pauli-block p)n ...
2008-11-01
[Improvement of the recognition probability about camouflage target based on BP neural network].
Using static Michelson interferometer to get the spectrum information of measurement targets for spectrum identification, under the condition that the interference length is constant, the system can be optimized by BP neural network algorithm for the mixed spectral separation process. Thereby it can realize improving the recognition probability of camouflage target. Collecting the spectrum information in field of view (FOV) by the interferometer and linear array CCD detector, composing the set of mixed spectrum data, with known absorption spectrum of the material as a hidden layer of rules, it used BP neural network to separate the mixed spectrum data. Experiment with different distances, different combinations of mixed background spectrum as the initial data, using steel target (size: 1.5 m x 1.5 m) made of four kinds, the recognition probability of non-camouflage target is about 90% by BP neural network algorithm or the traditional algorithm, while the ...
2010-12-01
Energy Technology Data Exchange (ETDEWEB)
A procedure and software have been developed to transform the area distribution of the residual surface heights available from the measurement with the Micromap interferometric microscope into a two-dimensional (2D) power spectral density (PSD) distribution of the surface height. The procedure incorporates correction of one of the spectral distortions of the PSD measurement. The distortion appears as a shape difference between the tangential and sagittal PSD spectra deduced from the 2D PSD distribution for an isotropic surface. A detailed investigation of the origin of the anisotropy was performed, and a mathematical model was developed and used to correct the distortion. The correction employs a modulation transfer function (MTF) of the detector deduced analytically based on an experimentally confirmed assumption about the origin of the anisotropy due to the asymmetry of the read-out process of the instrument's CCD camera. The correction function has only ...
2005-05-12
Energy Technology Data Exchange (ETDEWEB)
The use of capacitance sensors for measuring phase concentrations in two-phase flow has gained popularity in recent years. In designing such sensors, there are many issues which must be considered in order to optimize performance: two-phase flow regime, permittivity of the phases, duct geometry, electrical shielding, desired spacial resolution of film thickness, and temperature variation in the flow field. These design issues are discussed and are used to optimize the design of a capacitance sensor which is used to measure vapor volume fraction in annular, two-phase vertical upflow and downflow in a square duct. The sensor was tested and implemented in a 12.7 mm square duct mounted in a flow boiling facility containing FC-72, a low permittivity dielectric fluid ({epsilon}{sub r} = 1.75). Using analytical modeling, an adjustable-length, parallel-plate design was developed and refined to achieve good sensitivity to flow conditions. The sensor output was calibrated for a stratified liquid ...
1995-12-31
Short wave length and high qualification of free-electron laser
International Nuclear Information System (INIS)
The oscillation experiment of free-electron laser (FEL) was carried at the wave length 488 nm. The space and time properties and power of FEL were investigated. The typical macropulse structure indicated the time interval 20 ms and the pulse width 2 to 3 ms. About 1 ns was necessary to build up FEL. The space distribution of FEL showed beautiful TEM_0_0 mode, TEM_0_1 and TEM_0_2 mode. On the basis of data, 39 #mu#W average power was calculated at 2.9 mA accumulated current per bunch by integrating each response of pixel of CCD camera. The peak power was 1.2 W. In the oscillator, FEL power was average 1.2 W, peak 38 kW. On the electron beam, the stability of head tail was controlled by 6-pole-Quadrupole-6-pole (SQS) system made by an experimental basis. We succeeded the single set test, setting up single set in the ring. The characteristic properties of electron beam evaporation mirror of photo oscillator were studied and then new type photo oscillator to obtain ...
1998-02-01
Research and development of neutron radiography in IAERU
Energy Technology Data Exchange (ETDEWEB)
In the Institute for Atomic Energy, Rikkyo University, just after the TRIGA-2 research reactor of 100 kW has attained the criticality, the cylindrical box for neutron radiography (NR) irradiation was made in the attached pool, and the research on NR was started in 1961. Thereafter in 1985, the vertical irradiation pipe was installed in the reactor tank, and the experiment for collecting the basic data was begun. In 1986, based on the obtained data, the NR irradiation facility on full scale was installed in No. 2 tangential horizontal experimental hole. As the main NR irradiation facilities, the vertical neutron irradiation pipe, the use of which is stopped now, the NR facility using the horizontal experimental hole (RUR/N2), the irradiation facility and ancillary facilities such as beam shutter, beam catcher and hoist are described. As the main equipments for NR, the imaging apparatuses of cooled type CCD, SIT and superhigh sensitivity, the image processors of ...
1995-03-01
Performance of the upgraded LTP-II at the ALS Optical Metrology Laboratory
Energy Technology Data Exchange (ETDEWEB)
The next generation of synchrotrons and free electron laser facilities requires x-ray optical systems with extremely high performance, generally of diffraction limited quality. Fabrication and use of such optics requires adequate, highly accurate metrology and dedicated instrumentation. Previously, we suggested ways to improve the performance of the Long Trace Profiler (LTP), a slope measuring instrument widely used to characterize x-ray optics at long spatial wavelengths. The main way is use of a CCD detector and corresponding technique for calibration of photo-response non-uniformity [J. L. Kirschman, et al., Proceedings of SPIE 6704, 67040J (2007)]. The present work focuses on the performance and characteristics of the upgraded LTP-II at the ALS Optical Metrology Laboratory. This includes a review of the overall aspects of the design, control system, the movement and measurement regimes for the stage, and analysis of the performance by a slope measurement of a ...
2008-07-14
Morphological classification and structural parameters for early-type galaxies in the Coma cluster
We present the results of an isophotal shape analysis of three samples of galaxies in the Coma cluster. Quantitative morphology, together with structural and photometric parameters, is given for each galaxy. Special emphasis has been placed on the detailed classification of early-type galaxies. The three samples are: i) a sample of 97 early-type galaxies brighter than m_B = 17.00 falling within one degree from the center of the Coma cluster; these galaxies were observed with CCD cameras, mostly in good to excellent resolution conditions; ii) a magnitude complete sample of 107 galaxies of all morphological types down to m_B = 17.00 falling in a circular region of 50 arcmin diameter, slightly offcentered to the North-West of the cluster center; the images for this and the next sample come from digitized photographic plates; iii) a complete comparison sample of 26 galaxies of all morphological types down to m_R = 16.05 (or m_B \\simeq 17.5), also in a region of 50 ...
1995-01-01
Electrical resistivity and thermal expansion coeffcient of carbon-black-filled compounds around T_g
International Nuclear Information System (INIS)
A Michelson interferometer and a CCD detector were used to measure the number of interference fringes related to the expansion length of rubber sample. The sample was situated in a microcryostat, and the temperature of the sample was varied from -200 .deg. C to +80 .deg. C. Various types of carbon black filled rubber (Duradene, Sn-SSBR) samples were used to determine the glass transition temperatures (T_g) and the thermal coeffcients (#alpha#). The mixing ratio was 0, 10, 30, 40, 50, or 70 parts per hundred of carbon black to Sn-SSBR rubber. For the unfilled rubber of Sn-SSBR, the T_g was about -24 .deg. C, and the thermal coeffcient was 1.18 X 10"-"4 .deg. C"-"1. The thermal coeffcients sharply increased around T_g for all samples, and decreased with increasing doping ratio of carbonblack from 0 .deg. C to 30 .deg. C. The volume resistivity was measured for natural rubber and EPDM rubber. They had maximum volume resistivities of 1.5 X 10"6 #OMEGA#m and 8.0 X 10"6 ...
2004-04-01
Energy Technology Data Exchange (ETDEWEB)
Authors developed a C-arm type radiosurgery system of the linear accelerator suitable for stereotactic radiation therapy and a software for arranging 3-dimensional therapy in the system. In this system, the gantry far conical irradiation of 4 MV (0.6-3 Gy/min) and 6 MV (0.9-4.5 Gy/min) X ray or electron beam for the therapy was connected to a newly designed C-arm and was made capable of rotating around either of the axes crossing vertically. With this system, it became unnecessary to move the bed table of the patient for getting suitable distribution of radiation dose. The local accuracy which was measured by the CCD videocamera on the gantry, was within 0.5 mm from the radiation center. The system made it possible to shorten the irradiation time and to improve the local accuracy of irradiating site. The clinical trial was begun from June, 1996. (K.H.)
1996-10-01
Energy Technology Data Exchange (ETDEWEB)
IMRT with inverse planning allows simultaneous integrated boost strategies that exploit the heterogeneous dose distribution within the planning target volumes (PTVs). In this scenario, the location of cold spots within the target becomes a crucial issue and has to be related to the distribution of the clonogenic cell density (CCD). The main aim of this work is to provide the means to calculate the optimal prescription dose in a relative inhomogeneous dose distribution. To achieve this, the prescription dose has to be assigned to obtain the same tumor control probability (TCP) as the ideal homogeneous distribution, taking into account different CCDs in different PTVs (i.e. visible and subclinical regions). An adapted formulation of the linear-quadratic model, within the F-factor formalism, has been derived to preserve a chosen TCP value for the whole target volume. The F-factor has been investigated to show its potential applications in clinical practice.
2008-10-07
The models of experimental magnetic measurements of various biological samples
International Nuclear Information System (INIS)
Complete text of publication follows. At the Geomagnetic Institute, in the Laboratory for paleomagnetism and archeomagnetism research and at the Geomagnetic Observatory, Grocka (GCK) during the period from November 2004 to February 2008 the researchers carried out experimental magnetic measurements of the total-intensity gradient of the magnetic field vector (changes in the total magnetisation vector) of various biomaterials. Measurements of the gradient total intensity of the magnetic field vector were carried out by GSM-19 magnetometers of high accuracy and recording resolution (accuracy: #DELTA#F=0.1 nT; sampling rate: 1-5 per second). During these experimental biomagnetic measurements samples of water, tissue, blood, cotton, wool, pitch and magnetite-powder were used. In this study, the part of the biomagnetic measurement results relate to the water, blood and tissue. The results of the measurements of gradient total-intensity of the magnetic field for the ...
2009-08-23
The Pamela Cosmic Ray Space Observatory: Detector, Objectives and First Results
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15 2006 in a $350\\times 600 km$ orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the Calorimeter, ...
2009-01-01
Testing Effective Quantum Gravity with Gravitational Waves from Extreme-Mass-Ratio Inspirals
Testing deviation of GR is one of the main goals of the proposed {\\emph{Laser Interferometer Space Antenna}}, a space-based gravitational-wave observatory. For the first time, we consistently compute the generation of gravitational waves from extreme-mass ratio inspirals (stellar compact objects into supermassive black holes) in a well-motivated alternative theory of gravity, that to date remains weakly constrained by double binary pulsar observations. The theory we concentrate on is Chern-Simons (CS) modified gravity, a 4-D, effective theory that is motivated both from string theory and loop-quantum gravity, and which enhances the Einstein-Hilbert action through the addition of a dynamical scalar field and the parity-violating Pontryagin density. We show that although point particles continue to follow geodesics in the modified theory, the background about which they inspiral is a modification to the Kerr metric, which imprints a CS correction on the ...
2009-01-01
Swift panchromatic observations of the bright gamma-ray burst GRB050525a
The bright gamma-ray burst GRB050525a has been detected with the Swift observatory, providing unique multiwavelength coverage from the very earliest phases of the burst. The X-ray and optical/UV afterglow decay light curves both exhibit a steeper slope ~0.15 days after the burst, indicative of a jet break. The timing of the jet break combined with the total gamma-ray energy of the burst constrains the opening angle of the jet to be 2.5 degrees. We derive an empirical `time-lag' redshift from the BAT data of z_hat = 0.69 +/- 0.02, in good agreement with the spectroscopic redshift of 0.61. Prior to the jet break, the X-ray data can be modelled by a simple power law with index alpha = -1.2. However after 300s the X-ray flux brightens by about 30% compared to the power-law fit. The optical/UV data have a more complex decay, with evidence of a rapidly falling reverse shock component that dominates in the first minute or so, giving way to a flatter forward shock ...
2006-01-01
Stereoscopic observations of a solar hard x-ray flare with Ulysses, PVO, GRO and Yohkoh spacecraft
Energy Technology Data Exchange (ETDEWEB)
Hard X-ray/gamma-ray spectrometers aboard two interplanetary spacecraft, Ulysses and Pioneer Venus Orbiter (PVO), and two near-Earth spacecraft, Yohkoh and Compton Gamma Ray Observatory (GRO/BATSE), are currently in operation. A unique set of circumstances have permitted the observation of the 15 November 1991 (2238 UT) flare by all the four instruments. This intense flare (GOES class X 1.5) was associated with the bright (3B) H-alpha flare located on the disk (S13, W19) in the active region 6919. At the time of the flare, the Ulysses and PVO spacecraft were located respectively 101[degree] and 52[degree] west of the Sun-Earth line. Thus the view angles for the PVO and Ulysses instruments were quite different from those of the near-Earth instruments on GRO and Yohkoh. The preliminary photon energy spectra observed by the four instruments at different times during the flare will be presented and their implications regarding the directivity of hard X-ray sources in ...
1992-01-01
Energy Technology Data Exchange (ETDEWEB)
The second list of objects in the Second Biurakan Spectral Sky Survey of the region centered on alpha 09h50m, delta +55 deg 00 arcmin is given. The list contains data on 110 objects and galaxies of a peculiar physical nature and 24 blue stars. The observations were made with the 40-52 arcsec Schmidt telescope of the Biurakan Astrophysical Observatory with a set of three objective prisms using Kodak IIIaJ and IIIaF emulsions sensitized in nitrogen. The area is found to contain 20 quasar candidates and four Seyfert galaxies, 27 blue stellar objects, 24 galaxies with an appreciable ultraviolet continuum, and 39 emission galaxies without appreciable ultraviolet radiation. The surface brightness of the quasars and Seyferts on the considered area down to the limiting magnitude 19.5 M is more than 1.5 per square degree with allowance for the already known quasars. The surface density of emission galaxies is about four per square degree. 7 references.
1984-07-01
Observing Evolution in the Supergranular Length Scale During Periods of Low Solar Activity
We present the initial results of an observational study into the variation of the dominant length-scale of quiet solar emission: supergranulation. This length-scale reflects the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Sun's interior. We demonstrate that a net difference of ~0.5Mm in the supergranular emission length-scale occurs when comparing observations cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the datasets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length-scale over multiple solar minima by analyzing a subset of the Mt Wilson Solar Observatory (MWO) Ca II K image record. The observations and analysis presented provide a tantalizing look ...
2011-01-01
KINEMATICS AT THE EDGE OF THE GALACTIC BULGE: EVIDENCE FOR CYLINDRICAL ROTATION
International Nuclear Information System (INIS)
We present new results from BRAVA, a large-scale radial velocity survey of the Galactic bulge, using M giant stars selected from the Two Micron All Sky Survey catalog as targets for the Cerro Tololo Inter-American Observatory 4 m Hydra multi-object spectrograph. The purpose of this survey is to construct a new generation of self-consistent bar models that conform to these observations. We report the dynamics for fields at the edge of the Galactic bulge at latitudes b = -8 deg. and compare to the dynamics at b = -4 deg. We find that the rotation curve V(r) is the same at b = -8 deg. as at b = -4 deg. That is, the Galactic boxy bulge rotates cylindrically, as do boxy bulges of other galaxies. The summed line-of-sight velocity distribution at b = -8 deg. is Gaussian, and the binned longitude-velocity plot shows no evidence for either a (disk) population with cold dynamics or for a (classical bulge) population with hot dynamics. The observed kinematics are well modeled ...
2009-09-10
Integral Field Unit Observations of NGC 4302: Kinematics of the Diffuse Ionized Gas Halo
We present moderate resolution spectroscopy of extraplanar diffuse ionized gas (EDIG) emission in the edge-on spiral galaxy NGC 4302. The spectra were obtained with the SparsePak integral field unit (IFU) at the WIYN Observatory. The spectra are used to construct position-velocity (PV) diagrams at several ranges of heights above the midplane. Azimuthal velocities are directly extracted from the PV diagrams using the envelope tracing method, and indicate an extremely steep dropoff in rotational velocity with increasing height, with magnitude ~30 km/s/kpc. We find evidence for a radial variation in the velocity gradient on the receding side. We have also performed artificial observations of galaxy models in an attempt to match the PV diagrams. The results of a statistical analysis also favor a gradient of ~30 km/s/kpc. We compare these results with an entirely ballistic model of disk-halo flow, and find a strong dichotomy between the observed kinematics and those ...
2007-01-01
Gravitational waves from self-ordering scalar fields
Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively studied in the literature. In this paper we analyze the shape and amplitude of the gravitational wave spectrum on scales which are superhorizon at the time of production. Such gravitational waves are expected from the self ordering of randomly oriented scalar fields which can be present during a thermal phase transition or during preheating after hybrid inflation. We find that, if the gravitational wave source acts only during a small fraction of the Hubble time, the gravitational wave spectrum at frequencies lower than the expansion rate at the time of production behaves as $\\Omega_{\\rm GW}(f) \\propto f^3$ with an amplitude much too small to be observable by gravitational wave observatories like LIGO, LISA or BBO. On the other ...
2009-01-01
Future limits on isotropic Lorentz violation in the photon sector from UHECRs and TeV gamma rays
Present and future ultra-high-energy-cosmic-ray facilities (e.g., the Pierre Auger Observatory with South and North components) and TeV-gamma-ray telescope arrays (e.g., HESS/VERITAS and CTA) have the potential to set stringent indirect bounds on the nine Lorentz-violating parameters of nonbirefringent modified Maxwell theory minimally coupled to standard Dirac theory. Theoretically, the most interesting case is isotropic Lorentz violation, which is described by a single parameter [taken to vanish for the case of the standard Lorentz-invariant theory]. It appears possible to obtain in the future an upper (lower) indirect bound on this single isotropic Lorentz-violating parameter at the +10^{-21} (-10^{-17}) level. Comparison is made with existing and future direct bounds from laboratory experiments. The possible physics implications of upper bounds at the 10^{-21} level are also briefly discussed.
2011-01-01
One of the most interesting discoveries of the X-ray Telescope and EUV Imaging Spectrometer (EIS) on board the Hinode solar observatory is the presence of persistent high temperature high speed outflows from the edges of active regions. Measurements by EIS indicate that the outflows reach velocities of 50 km/s with spectral line asymmetries approaching 200 km/s. It has been suggested that these outflows may lie on open field lines that connect to the heliosphere, and that they could potentially be a significant source of the slow speed solar wind. A direct link has been difficult to establish, however. In this letter, we use EIS measurements of spectral line intensities that are sensitive to changes in the relative abundance of Si and S as a result of the first ionization potential (FIP) effect, to measure the chemical composition in the outflow regions of AR 10978 over a period of 5 days in December 2007. We find that Si is always enhanced over S by a factor of ...
2010-01-01
Discovery of a strong Baldwin effect in mid-infrared AGN lines
We present the discovery of a Baldwin effect in 8 nearby Seyfert galaxies for the three most prominent mid-infrared forbidden emission lines observable from the ground that are commonly found in AGN, [ArIII](8.99 micron), [SIV](10.51 micron), and [NeII](12.81 micron). The observations were carried out using the VLT/VISIR imager and spectroraph at the ESO/Paranal observatory. The bulk of the observed line emission comes from the inner <0.4 arcsec which corresponds to spatial scales <100 pc in our object sample. The correlation index is approximately -0.6 without significant difference among the lines. This is the strongest anti-correlation between line equivalent width and continuum luminosity found so far. In the case of Circinus, we show that despite the use of mid-infrared lines, obscuration by either the host galaxy or the circumnuclear dust torus might affect the equivalent widths. Given the small observed spatial scales from which most of the line ...
2008-01-01
Compact source origin of cosmic ray antiprotons
Energy Technology Data Exchange (ETDEWEB)
The flux of cosmic ray antiprotons with kinetic energies between /approximately/1 and 15 GeV is /approximately/5 times greater than the flux predicted on the basis of the leaky-box model. This excess is attributed to secondary antineutron production in compact sources. Because the antineutrons are not confined by the magnetic field of the compact source, they leave the interaction site, decay in interstellar space and account for the apparent excess cosmic ray antiproton flux. The escape and decay of neutrons produced in association with the antineutrons is a source of cosmic ray protons. Observations of the angular variation of the intensity and spectral shape of 100 MeV ..gamma..-rays produced by neutron-decay protons in the reaction p + p ..-->.. ..pi../sup 0/ ..-->.. 2..gamma.. could reveal compact-source cosmic ray production sites. COS-B observations of spectral hardening near point sources, and future high-resolution observations of galactic point sources by Gamma-1 and ...
1989-02-01
Chandra Observations of Nuclear X-ray Emission from a Sample of Radio Sources
We present the X-ray properties of a sample of 17 radio sources observed with the Chandra X-ray Observatory as part of a project aimed at studying the X-ray emission from their radio jets. In this paper, we concentrate on the X-ray properties of the unresolved cores. The sample includes 16 quasars (11 core-dominated and 5 lobe-dominated) in the redshift range z=0.30--1.96, and one low-power radio-galaxy at z=0.064. No diffuse X-ray emission is present around the cores of the quasars, except for the nearby low-power galaxy that has diffuse emission on a scale and with a luminosity consistent with other FRIs. No high-amplitude, short-term variability is detected within the relatively short Chandra exposures. However, 1510-089 shows low-amplitude flux changes with a timescale of $\\sim$25 minutes. The X-ray spectra of the quasar cores are generally well described by a single power law model with Galactic absorption. However, in six quasars we find soft X-ray excess ...
2003-01-01
A Population of Intergalactic Supernovae in Galaxy Clusters
We have discovered seven type Ia cluster supernovae (SNe) in the course of the Wise Observatory Optical Transients Search in the fields of galaxy clusters with redshifts between z=0.06 and z=0.2. Two of these events, SN 1998fc in Abell 403 (z=0.10) and SN 2001al in Abell 2122/4 (z = 0.066), have no obvious hosts. Both events appear projected on the halos of the central cD galaxies, but have velocity offsets of 750-2000 km/s relative to those galaxies, suggesting they are not bound to them. We use deep Keck imaging of the locations of the two SNe to put upper limits on the luminosities of possible dwarf hosts, M_R > -14 mag for SN 1998fc and M_R > -11.8 mag for SN 2001al. The fractions of the cluster luminosities in dwarf galaxies fainter than our limits are less than 3 x 10^-3 and 3 x 10^-4, respectively. Thus, 2/7 of the SNe would be associated with less than 3 x 10^-3 of the luminosity attributed to galaxies. We argue, instead, that the progenitors of both ...
2002-01-01
Energy Technology Data Exchange (ETDEWEB)
Diffuse {gamma}-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse {gamma}-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse {gamma}-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30{sup o} and 110{sup o} and between 136{sup o} and 216{sup o} and for Galactic latitudes between -10{sup o} and 10{sup o} are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region (l {element_of} [65{sup o}, 85{sup o}]). For the Cygnus region, the flux is twice the ...
2008-05-14
RADIAL DISTRIBUTION OF STARS, GAS AND DUST IN SINGS GALAXIES. I. SURFACE PHOTOMETRY AND MORPHOLOGY
International Nuclear Information System (INIS)
We present ultraviolet through far-infrared (FIR) surface brightness profiles for the 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). The imagery used to measure the profiles includes Galaxy Evolution Explorer UV data, optical images from Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and Sloan Digital Sky Survey, near-IR data from Two Micron All Sky Survey, and mid- and FIR images from Spitzer. Along with the radial profiles, we also provide multi-wavelength asymptotic magnitudes and several nonparametric indicators of galaxy morphology: the concentration index (C 42), the asymmetry (A), the Gini coefficient (G), and the normalized second-order moment of the brightest 20% of the galaxy's flux (M-bar20). In this paper, the first of a series, we describe the technical aspects regarding the surface photometry, and present a basic analysis of the global and structural properties of the SINGS galaxies ...
2009-10-01
Measuring q sub 0 using supernovae at z approx 0. 3
Energy Technology Data Exchange (ETDEWEB)
The measurement of q{sub o} is extremely important for understanding the quantity of matter in our universe. The measurement of q{sub o} using supernovae of type Ia as standard candles is appealing because it requires less modeling than other methods using galaxies. The challenge with using supernovae to measure q{sub o} is in finding enough of them. In order to find supernovas, we have constructed a very popular f/1 camera for the 3.9m Anglo-Australian Telescope. The camera uses reducing optics that put a 17 in. {times} 17 in. field on a 1024 {times} 1024 pixel Thomson CCD. Using this system, we image to 23rd magnitude in five minutes. We have developed a software package that uses image subtraction to find supernovae that are approximately magnitude 22.4 or brighter in these images. One field can be processed every 6.6 minutes on a relatively unloaded VAX 6000-6510. We estimate that this system should find one supernova in every 105--139 images (about two nights ...
1992-07-01
Families of ellipsoidal stellar systems adn the formation of dwarf elliptical galaxies
International Nuclear Information System (INIS)
Core radii and central surface brightnesses of bulges and elliptical galaxies are measured using CCD photometry obtained with the Canada-France-Hawaii Telescope (scale = 0''.22 pixel"-"1; seeing = 0''.45--1''.0 FWHM). The correlations between core parameters are derived and compared for ellipticals, bulges, dwarf spheroidal galaxies, dwarf irregular galaxies, and globular clusters. The results are as follows. 1. Ihe data confirm the existence of well-defined correlations between the core parameters of elliptical galaxies. More luminous ellipticals have larger core radii r/sub c/ and lower central surface brightnesses #mu#/sub 0v/. Galaxies with larger core radii have larger central velocity dispersions. The small, bright core of M32 is normal for a galaxy of M/sub B/ = -15.2. Radio ellipticals and brightest cluster galaxies satisfy the correlations. 2. The bulges of disk galaxies are basically similar to elliptical galaxies. Their cores have slightly smaller r/sub ...
Computer vision algorithms in DNA ploidy image analysis
The high incidence and mortality rates of prostate cancer have stimulated research for prevention, early diagnosis and appropriate treatment. DNA ploidy status of tumour cells is an important parameter with diagnostic and prognostic significance. In the current study, DNA ploidy analysis was performed using image cytometry technique and digital image processing and analysis. Tissue samples from prostate patients were stained using the Feulgen method. Images were acquired using a digital imaging microscopy system consisting of an Olympus BX-50 microscope equipped with a color CCD camera. Segmentation of such images is not a trivial problem because of the uneven background, intensity variations within the nuclei and cell clustering. In this study specific algorithms were developed in Matlab based on the most prominent image segmentation approaches that emanate from the field of Mathematical Morphology, focusing on region-based watershed segmentation. First biomedical ...
2006-03-01
Energy Technology Data Exchange (ETDEWEB)
In this study, the biosorption of Cd(II), Ni(II) and Pb(II) on Aspergillus niger in a batch system was investigated, and optimal condition determined by means of central composite design (CCD) under response surface methodology (RSM). Biomass inactivated by heat and pretreated by alkali solution was used in the determination of optimal conditions. The effect of initial solution pH, biomass dose and initial ion concentration on the removal efficiency of metal ions by A. niger was optimized using a design of experiment (DOE) method. Experimental results indicated that the optimal conditions for biosorption were 5.22 g/L, 89.93 mg/L and 6.01 for biomass dose, initial ion concentration and solution pH, respectively. Enhancement of metal biosorption capacity of the dried biomass by pretreatment with sodium hydroxide was observed. Maximal removal efficiencies for Cd(II), Ni(III) and Pb(II) ions of 98, 80 and 99% were achieved, respectively. The biosorption capacity of A. ...
2009-10-15
TIME EVOLUTION OF CORONAL MAGNETIC HELICITY IN THE FLARING ACTIVE REGION NOAA 10930
International Nuclear Information System (INIS)
To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930 during the time period of December 8-14. The coronal helicity is calculated based on the 3D nonlinear force-free magnetic fields reconstructed by the weighted optimization method of Wiegelmann, and is compared with the amount of helicity injected through the photospheric surface of the AR. The helicity injection is determined from the magnetic helicity flux density proposed by Pariat et al. using Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms. The major findings of this study are the following. (1) The time profile of the coronal helicity shows a good correlation with that of the helicity accumulation by injection through the surface. (2) The coronal helicity of the AR is estimated to be -4.3 x 10"4"3 ...
2010-09-10
Energy Technology Data Exchange (ETDEWEB)
In 2004, the Southeastern France regional council asked the regional health observatory to conduct an environmental health inventory to i) identify environmental health problems in this area; ii) examine the relations between environmental exposure to pollutants and human health; and iii) help public officials to identify priorities in this area. We collected and validated data from national, regional and local institutions, constructed environmental (levels of emissions and pollutants), health (mortality, incidence, prevalence) and behavioral indicators (e.g., complaints about odors), and compared these over time and between places when possible. For each topic, we summarized current knowledge about the links between environment and health. In southeastern France, as in other French areas, indoor air pollution, home and leisure injuries and other home-related risks are public health issues. Other topics are more significant or particular to southeastern France: ...
2005-07-15
International Nuclear Information System (INIS)
We derive stellar masses, ages, and star formation histories (SFHs) of massive early-type galaxies in the z = 1.237 RDCS1252.9-2927 cluster and compare them with those measured in a similarly mass-selected sample of field contemporaries drawn from the Great Observatories Origin Deep Survey South Field. Robust estimates of these parameters are obtained by comparing a large grid of composite stellar population models with 8-9 band photometry in the rest-frame near-ultraviolet, optical, and IR, thus sampling the entire relevant domain of emission of the different stellar populations. Additionally, we present new, deep U-band photometry of both fields, giving access to the critical far-ultraviolet rest frame, in order to empirically constrain the dependence of the most recent star formation processes on the environment. We also analyze the morphological properties of both samples to examine the dependence of their scaling relations on their mass and environment. We ...
2010-01-20
An accident of misidentification has brought to light the interesting system HD 191588, a new RS CVn-type spectroscopic binary. A radial-velocity study of the primary star, the only seen component, carried out at the Observatoire de Haute-Provence with the Coravel instrument and subsequently at the Cambridge Observatories with a similar one, reveals two orbital motions: a short-period orbit (60 days) and a long-period one (about 4.5 years), so this star is a triple system. The following orbital elements are obtained: (1) for the long-period orbit P = 1667+/-17 days, T = 50901 +/-67 MJD, Gamma = +2.09 +/-0.07 km/s, K = 2.51 +/-0.13 km/s, e = 0.18 +/-0.04, omega = 228deg +/- 14 deg, a1 sin i = 56.7 +/- 3.0 Gm, f(m) = 0.0026 +/-0.0004 M_sun, and (2) for the short-period orbit P = 60.0269 +/-0.0016 days, T = 50482.6 +/-3.3 MJD, gamma is var., K = 24.03 +/- 0.09 km/s, e = 0.012 +/-0.004, omega = 233 deg +/-19deg, a1 sin i = 19.83 +/-0.07 Gm, f(m) = 0.0865 +/-0.0009 ...
2003-01-01
Energy Technology Data Exchange (ETDEWEB)
Spectroscopic constants and absolute intensities from more than 2150 transitions belonging to 52 bands of 7 isotopic species of carbon dioxide have been determined using a multispectrum nonlinear least-squares fitting technique. The spectral data (0.01 cm{sup -1} resolution) were obtained at room temperature and low pressure (<10 Torr) using the McMath-Pierce Fourier transform spectrometer of the National Solar Observatory on Kitt Peak, Arizona. A natural sample of carbon dioxide with absorption path lengths between 24 and 385m were used in recording the spectra. The first measurements have been made of the theoretically predicted 2v{sub 2}{sup 2} 2+v{sub 3} {open_quotes}forbidden{close_quotes} band of {sup 12}CO{sub 2}. Two bands which have not been predicted so far, one belonging to {sup 13}CO{sub 2} and the other to {sup 13}C{sup 16}O{sup 18}O, have been identified. The measured line intensities obtained for each band have been analyzed to determine the ...
1995-12-31
International Nuclear Information System (INIS)
Research highlights: #-># The building occupancy affecting the cooling load prediction is studied. #-># PENN model is adopted in this study for predicting the building cooling load. #-># Statistical approach is adopted to result a less prejudice prediction performance. #-># Results show that occupancy data can significantly improve the prediction. -- Abstract: Building cooling load prediction is one of the key factors in the success of energy-saving measures. Many computational models available in the industry today have been developed from either forward or inverse modeling approaches. However, most of these models require extensive computer resources and involve lengthy computation. This paper discusses the use of data-driven intelligent approaches, a probabilistic entropy-based neural (PENN) model to predict the cooling load of a building. Although it is common knowledge that the presence and activity of building occupants have a significant impact on the required ...
2011-07-01
International Nuclear Information System (INIS)
We have observed the CH_3OH J = 2-1, SiO J = 2-1, C"3"4S J = 2-1, H"1"3CO"+ J = 1-0, HN"1"3C J = 1-0, CCH N = 1-0, OCS J = 8-7, and SO J_N = 2_2-1_1 lines toward 20 massive clumps, including Midcourse Space Experiment (MSX) 8 #mu#m dark sources (infrared dark clouds) and MSX 8 #mu#m sources, by using the Nobeyama Radio Observatory 45 m telescope. We have found that the velocity widths of the CH_3OH and C"3"4S lines are broader than those of the H"1"3CO"+ line in the MSX dark sources. On the other hand, they are comparable to the velocity width of the H"1"3CO"+ line in the MSX sources. In addition, the [SiO]/[H"1"3CO"+] abundance ratio is found to be enhanced in the MSX dark sources in comparison with the MSX sources. These results suggest that shocks caused by interaction between an outflow and an ambient dense gas would have substantial impact on the chemical composition of the MSX dark sources. The velocity widths of the CH_3OH and C"3"4S lines relative to that ...
2010-05-10
Laser: a Tool for Optimization and Enhancement of Analytical Methods
Energy Technology Data Exchange (ETDEWEB)
In this work, we use lasers to enhance possibilities of laser desorption methods and to optimize coating procedure for capillary electrophoresis (CE). We use several different instrumental arrangements to characterize matrix-assisted laser desorption (MALD) at atmospheric pressure and in vacuum. In imaging mode, 488-nm argon-ion laser beam is deflected by two acousto-optic deflectors to scan plumes desorbed at atmospheric pressure via absorption. All absorbing species, including neutral molecules, are monitored. Interesting features, e.g. differences between the initial plume and subsequent plumes desorbed from the same spot, or the formation of two plumes from one laser shot are observed. Total plume absorbance can be correlated with the acoustic signal generated by the desorption event. A model equation for the plume velocity as a function of time is proposed. Alternatively, the use of a static laser beam for observation enables reliable determination of plume velocities even when ...
1997-01-01
Energy Technology Data Exchange (ETDEWEB)
TiO{sub 2} is a vital material in several technologies including, photocatalysis, gas sensing, biomaterials and optical coatings. Among the several crystal structures of this oxide, rutile has the highest density and microhardness, the highest index of refraction and the highest temperature stability. The processing of dense polycrystalline materials often includes the addition of a liquid-forming phase at higher temperatures. This technique is known as liquid-phase sintering and has been studied extensively. Rutile boundaries containing an amorphous phase have been used to study boundary migration and grain-boundary grooving. Visible-light (VLM), scanning electron (SEM) and transmission electron microscopy (TEM) in addition to electron-backscatter diffraction (EBSD) and a focused-ion beam (FIB) tool were used to characterize boundary migration in rutile. EBSD analysis was carried out on a Philips XL30 FEG SEM equipped with a DigiView 1612 high-resolution, high-speed ...
2003-08-01
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