GPU-Based Real-Time Volumetric Ultrasound Image Reconstruction for a Ring Array

PubMed Central

Choe, Jung Woo; Nikoozadeh, Amin; Oralkan, Ömer; Khuri-Yakub, Butrus T.

2014-01-01

Synthetic phased array (SPA) beamforming with Hadamard coding and aperture weighting is an optimal option for real-time volumetric imaging with a ring array, a particularly attractive geometry in intracardiac and intravascular applications. However, the imaging frame rate of this method is limited by the immense computational load required in synthetic beamforming. For fast imaging with a ring array, we developed graphics processing unit (GPU)-based, real-time image reconstruction software that exploits massive data-level parallelism in beamforming operations. The GPU-based software reconstructs and displays three cross-sectional images at 45 frames per second (fps). This frame rate is 4.5 times higher than that for our previously-developed multi-core CPU-based software. In an alternative imaging mode, it shows one B-mode image rotating about the axis and its maximum intensity projection (MIP), processed at a rate of 104 fps. This paper describes the image reconstruction procedure on the GPU platform and presents the experimental images obtained using this software. PMID:23529080

The Cherenkov Telescope Array: Exploring the Very-high-energy Sky from ESO's Paranal Site

NASA Astrophysics Data System (ADS)

Hofmann, W.

2017-06-01

The Cherenkov Telescope Array (CTA) is a next-generation observatory for ground-based very-high-energy gamma-ray astronomy, using the imaging atmospheric Cherenkov technique to detect and reconstruct gamma-ray induced air showers. The CTA project is planning to deploy 19 telescopes on its northern La Palma site, and 99 telescopes on its southern site at Paranal, covering the 20 GeV to 300 TeV energy domain and offering vastly improved performance compared to currently operating Cherenkov telescopes. The combination of three different telescope sizes (23-, 12- and 4-metre) allows cost-effective coverage of the wide energy range. CTA will be operated as a user facility, dividing observation time between a guest observer programme and large Key Science Projects (KSPs), and the data will be made public after a one-year proprietary period. The history of the project, the implementation of the arrays, and some of the major science goals and KSPs, are briefly summarised.

LSA Low-cost Solar Array project

NASA Technical Reports Server (NTRS)

1978-01-01

The activities of the Low-Cost Silicon Solar Array Project during the period October through December, 1977 are reported. The LSSA Project is assigned responsibility for advancing silicon solar array technology while encouraging industry to reduce the price of arrays to a level at which photovoltaic electric power systems will be competitive with more conventional power sources early in the next decade. Set forth are the goals and plans with which the Project intends to accomplish this and the progress that was made during the quarter.

Low-cost Solar Array (LSA) project

NASA Technical Reports Server (NTRS)

1978-01-01

The activities of the Low-Cost Solar Array Project are described for the period April through June 1978. The Project is assigned responsibility for advancing solar array technology while encouraging industry to reduce the price of arrays to a level at which photovoltaic electric power systems will be competitive with more conventional power sources early in the next decade. Set forth are the goals and plans with which the Project intends to accomplish this and the progress that was made during the quarter.

Real-time detection of an extremely high signal-to-noise ratio fast radio burst during observations of PSR J2124-3358

NASA Astrophysics Data System (ADS)

Oslowsk, S.; Shannon, R. M..; Jameson, Andrew; Sarkissian, J. M..; Bailes, M.; Andreoni, I.; Bhat, N. D. R..; Coles, W. A.; Dai, S.; Dempsey, J.; Hobbs, G.; Keith, M. J.; Kerr, M.; Manchester, R. N.; Lasky, P. D.; Levin, Y.; Parthasarathy, A.; Ravi, V.; Reardon, D. J.; Rosado, P. A.; Russell, C. J.; Spiewak, R.; Van Straten, W.; Toomey, L.; Wang, J. B.; Wen, L.; You, X.-P.; Zhang, L.; Zhang, S.; Zhu, X.-J.

2018-03-01

The Parkes Pulsar Timing Array (Manchester et al. 2013) project monitors pulse times of arrival for 24 millisecond pulsars in the Galaxy on a fortnightly cadence using the multibeam receiver on the CSIRO 64-m Parkes Telescope.

Wavefront sensing and adaptive control in phased array of fiber collimators

NASA Astrophysics Data System (ADS)

Lachinova, Svetlana L.; Vorontsov, Mikhail A.

2011-03-01

A new wavefront control approach for mitigation of atmospheric turbulence-induced wavefront phase aberrations in coherent fiber-array-based laser beam projection systems is introduced and analyzed. This approach is based on integration of wavefront sensing capabilities directly into the fiber-array transmitter aperture. In the coherent fiber array considered, we assume that each fiber collimator (subaperture) of the array is capable of precompensation of local (onsubaperture) wavefront phase tip and tilt aberrations using controllable rapid displacement of the tip of the delivery fiber at the collimating lens focal plane. In the technique proposed, this tip and tilt phase aberration control is based on maximization of the optical power received through the same fiber collimator using the stochastic parallel gradient descent (SPGD) technique. The coordinates of the fiber tip after the local tip and tilt aberrations are mitigated correspond to the coordinates of the focal-spot centroid of the optical wave backscattered off the target. Similar to a conventional Shack-Hartmann wavefront sensor, phase function over the entire fiber-array aperture can then be retrieved using the coordinates obtained. The piston phases that are required for coherent combining (phase locking) of the outgoing beams at the target plane can be further calculated from the reconstructed wavefront phase. Results of analysis and numerical simulations are presented. Performance of adaptive precompensation of phase aberrations in this laser beam projection system type is compared for various system configurations characterized by the number of fiber collimators and atmospheric turbulence conditions. The wavefront control concept presented can be effectively applied for long-range laser beam projection scenarios for which the time delay related with the double-pass laser beam propagation to the target and back is compared or even exceeds the characteristic time of the atmospheric turbulence change - scenarios when conventional target-in-the-loop phase-locking techniques fail.

Recent development of infrasound monitoring network in Romania

NASA Astrophysics Data System (ADS)

Ghica, Daniela; Popa, Mihaela; Ionescu, Constantin

2017-04-01

The second half of 2016 was marked at National Institute for Earth Physics (NIEP) by a significant development of infrasound monitoring infrastructure in Romania. In addition to IPLOR, the 6-element acoustic array installed at Plostina, in the central part of Romania, since 2009, two other four-element arrays were deployed. The first one, BURARI infrasound research array, was deployed in late July 2016, under a joint effort of AFTAC, USA and NIEP, in the northern part of Romania, in Bucovina region. The sites, placed in vicinity of the central elements of BURAR seismic array (over 1.2 km aperture), are equipped with Chaparral Physics Model 21 microbarometers and Reftek RT 130 data loggers. The data, used mainly for research purposes within the scientific collaboration project between NIEP and AFTAC, are available to scientific community. The second one is a PTS portable infrasound array (I67RO) deployed for one year, starting with the end of September 2016, within a collaboration project between NIEP and PTS of the Preparatory Commission for CTBTO. This array is located in the western part of Romania, at Marisel, Cluj County, covering a 0.9 km aperture and being equipped with CEA/DAM MB2005 microbarometers and Reftek RT 130 data loggers. This joint experiment aims to contribute both to advanced understanding of infrasound sources in Central-Europe and to ARISE design study project, as an expansion of the spatial coverage of the European infrasound network. The data recorded by the three infrasound arrays deployed in Romania, during a same time interval (October - December 2016) were processed into detection arrival bulletins applying CEA/DASE PMCC algorithm embedded in DTK-GPMCC (extended CTBTO NDC-in-a-box) and WinPMCC software applications. The results were plotted and analyzed using DTK-DIVA software (extended CTBTO NDC-in-a-box), in order to assess detectability of each station, as well as the capacity of fusing detections into support of infrasound monitoring activity at NIEP. We present infrasound signals generated by an impulsive event (accidental explosion of a train carrying liquid petroleum gas in Hitrino, Bulgaria) recorded on these three arrays. The features calculated for the arrivals detected (backazimuth, arrival time, frequency and celerity) are used to associate signals with event and observe individually array performance.

Experimental results for a prototype 3-D acoustic imaging system using an ultra-sparse planar array

NASA Astrophysics Data System (ADS)

Impagliazzo, John M.; Chiang, Alice M.; Broadstone, Steven R.

2002-11-01

A handheld high resolution sonar has been under development to provide Navy Divers with a 3-D acoustic imaging system for mine reconnaissance. An ultra-sparse planar array, consisting of 121 1 mm x1 mm, 2 MHz elements, was fabricated to provide 3-D acoustic images. The array was 10 cm x10 cm. A full array at this frequency with elements at half-wavelength spacing would consist of 16384 elements. The first phase of testing of the planar array was completed in September 2001 with the characterization of the array in the NUWC Acoustic Test Facility (ATF). The center frequency was 2 MHz with a 667 kHz bandwidth. A system-level technology demonstration will be conducted in July 2002 with a real-time beamformer and near real-time 3-D imaging software. The demonstration phase consists of imaging simple targets at a range of 3 m in the ATF. Experimental results obtained will be reported on. [Work supported by the Defense Applied Research Project Agency, Advance Technology Office, Dr. Theo Kooij, Program Manager.

The Data Acquisition System of the Stockholm Educational Air Shower Array

NASA Astrophysics Data System (ADS)

Hofverberg, P.; Johansson, H.; Pearce, M.; Rydstrom, S.; Wikstrom, C.

2005-12-01

The Stockholm Educational Air Shower Array (SEASA) project is deploying an array of plastic scintillator detector stations on school roofs in the Stockholm area. Signals from GPS satellites are used to time synchronise signals from the widely separated detector stations, allowing cosmic ray air showers to be identified and studied. A low-cost and highly scalable data acquisition system has been produced using embedded Linux processors which communicate station data to a central server running a MySQL database. Air shower data can be visualised in real-time using a Java-applet client. It is also possible to query the database and manage detector stations from the client. In this paper, the design and performance of the system are described

Student Projects in Cosmic Ray Detection

ERIC Educational Resources Information Center

Brouwer, W.; Pinfold, J.; Soluk, R.; McDonough, B.; Pasek, V.; Bao-shan, Zheng

2009-01-01

The Alberta Large-area Time-coincidence Array (ALTA) study has been in existence for about 10 years under the direction of Jim Pinfold of the Centre for Particle Physics at the University of Alberta. The purpose of the ALTA project is to involve Alberta high schools, and primarily their physics classes, to assist in the detection of the presence…

Submicron Systems Architecture Project

DTIC Science & Technology

1981-11-01

This project is concerned with the architecture , design , and testing of VLSI Systems. The principal activities in this report period include: The Tree Machine; COPE, The Homogeneous Machine; Computational Arrays; Switch-Level Model for MOS Logic Design; Testing; Local Network and Designer Workstations; Self-timed Systems; Characterization of Deadlock Free Resource Contention; Concurrency Algebra; Language Design and Logic for Program Verification.

Sound System Engineering & Optimization: The effects of multiple arrivals on the intelligibility of reinforced speech

NASA Astrophysics Data System (ADS)

Ryan, Timothy James

The effects of multiple arrivals on the intelligibility of speech produced by live-sound reinforcement systems are examined. The intent is to determine if correlations exist between the manipulation of sound system optimization parameters and the subjective attribute speech intelligibility. Given the number, and wide range, of variables involved, this exploratory research project attempts to narrow the focus of further studies. Investigated variables are delay time between signals arriving from multiple elements of a loudspeaker array, array type and geometry and the two-way interactions of speech-to-noise ratio and array geometry with delay time. Intelligibility scores were obtained through subjective evaluation of binaural recordings, reproduced via headphone, using the Modified Rhyme Test. These word-score results are compared with objective measurements of Speech Transmission Index (STI). Results indicate that both variables, delay time and array geometry, have significant effects on intelligibility. Additionally, it is seen that all three of the possible two-way interactions have significant effects. Results further reveal that the STI measurement method overestimates the decrease in intelligibility due to short delay times between multiple arrivals.

Multipoint photonic doppler velocimetry using optical lens elements

DOEpatents

Frogget, Brent Copely; Romero, Vincent Todd

2014-04-29

A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

The 235U prompt fission neutron spectrum measured by the Chi-Nu project at LANSCE

DOE PAGES

Gomez, J. A.; Devlin, M.; Haight, R. C.; ...

2017-09-13

The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced with neutrons ranging from 0.7 MeV and above. Using a two arm time-of-flight (TOF) technique, the fission neutrons are measured in one of two arrays: a 22- 6Li glass array for lower energies, or a 54-liquid scintillator array for outgoing energies of 0.5 MeV and greater. Presented here are the collaboration's preliminary efforts at measuring the 235U PFNS.

The 235U prompt fission neutron spectrum measured by the Chi-Nu project at LANSCE

NASA Astrophysics Data System (ADS)

Gomez, J. A.; Devlin, M.; Haight, R. C.; O'Donnell, J. M.; Lee, H. Y.; Mosby, S. M.; Taddeucci, T. N.; Kelly, K. J.; Fotiades, N.; Neudecker, D.; White, M. C.; Talou, P.; Rising, M. E.; Solomon, C. J.; Wu, C. Y.; Bucher, B.; Buckner, M. Q.; Henderson, R. A.

2017-09-01

The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced with neutrons ranging from 0.7 MeV and above. Using a two arm time-of-flight (TOF) technique, the fission neutrons are measured in one of two arrays: a 22-6Li glass array for lower energies, or a 54-liquid scintillator array for outgoing energies of 0.5 MeV and greater. Presented here are the collaboration's preliminary efforts at measuring the 235U PFNS.

A second fast radio burst discovered with Parkes Telescope within 50 hours: FRB180311 in the direction of PSR J2129-5721

NASA Astrophysics Data System (ADS)

Oslowski, S.; Shannon, R. M.; Jameson, Andrew; Hobbs, G.; Bailes, M.; Bhat, N. D. R.; Coles, W. A.; Dai, S.; Dempsey, J.; Keith, M. J.; Kerr, M.; Manchester, R. N.; Lasky, D. P.; Levin, Y.; Parthasarathy, A.; Ravi, V.; Reardon, D. J.; Russell, C. J.; Sarkissian, J. M.; Spiewak, R.; Van Straten, W.; Toomey, L.; Wang, J. B.; Wen, L.; You, X.-P.; Zhang, L.; Zhang, S.; Zhu, X.-J.

2018-03-01

The Parkes Pulsar Timing Array (Manchester et al. 2013) project monitors pulse times of arrival for 24 millisecond pulsars in the Galaxy on a fortnightly cadence using the multibeam receiver on the CSIRO 64-m Parkes Telescope.

Photonic Doppler velocimetry lens array probe incorporating stereo imaging

DOEpatents

Malone, Robert M.; Kaufman, Morris I.

2015-09-01

A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

Ultrasonic Phased Array Compressive Imaging in Time and Frequency Domain: Simulation, Experimental Verification and Real Application

PubMed Central

Bai, Zhiliang; Chen, Shili; Jia, Lecheng; Zeng, Zhoumo

2018-01-01

Embracing the fact that one can recover certain signals and images from far fewer measurements than traditional methods use, compressive sensing (CS) provides solutions to huge amounts of data collection in phased array-based material characterization. This article describes how a CS framework can be utilized to effectively compress ultrasonic phased array images in time and frequency domains. By projecting the image onto its Discrete Cosine transform domain, a novel scheme was implemented to verify the potentiality of CS for data reduction, as well as to explore its reconstruction accuracy. The results from CIVA simulations indicate that both time and frequency domain CS can accurately reconstruct array images using samples less than the minimum requirements of the Nyquist theorem. For experimental verification of three types of artificial flaws, although a considerable data reduction can be achieved with defects clearly preserved, it is currently impossible to break Nyquist limitation in the time domain. Fortunately, qualified recovery in the frequency domain makes it happen, meaning a real breakthrough for phased array image reconstruction. As a case study, the proposed CS procedure is applied to the inspection of an engine cylinder cavity containing different pit defects and the results show that orthogonal matching pursuit (OMP)-based CS guarantees the performance for real application. PMID:29738452

Near- and far-field infrasound monitoring in the Mediterranean area

NASA Astrophysics Data System (ADS)

Campus, Paola; Marchetti, Emanuele; Le Pichon, Alexis; Wallenstein, Nicolau; Ripepe, Maurizio; Kallel, Mohamed; Mialle, Pierrick

2013-04-01

The Mediterranean area is characterized by a number of very interesting sources of infrasound signals and offers a promising playground for the development of a deeper understanding of such sources and of the associated propagation models. The progress in the construction and certification of infrasound arrays belonging to the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in the vicinity of this area has been complemented, in the last decade, by the construction of infrasound arrays established by several European research groups. The University of Florence (UniFi) plays a crucial role for the detection of infrasound signals in the Mediterranean area, having deployed since several years two infrasound arrays on Stromboli and Etna volcanoes, and, more recently, three infrasound arrays in the Alpine area of NW Italy and one infrasound array on the Apennines (Mount Amiata), designed and established in the framework of the ARISE Project. The IMS infrasound arrays IS42 (Graciosa, Azores, Portugal) and IS48 (Kesra, Tunisia) recorded, since the time of their certification, a number of far-field events which can be correlated with some near-field records of the infrasound arrays belonging to UniFi. An analysis of the results and potentialities of infrasound source's detections in near and far-field realized by IS42, IS48 and UniFi arrays in the Mediterranean area, with special focus on volcanic events is presented. The combined results deriving from the analysis of data recorded by the Unifi arrays and by the IS42 and IS48 arrays, in collaboration with the Department of Analyse et Surveillance (CEA/DASE), will generate a synergy which will certainly contribute to the progress of the ARISE Project.

A class of least-squares filtering and identification algorithms with systolic array architectures

NASA Technical Reports Server (NTRS)

Kalson, Seth Z.; Yao, Kung

1991-01-01

A unified approach is presented for deriving a large class of new and previously known time- and order-recursive least-squares algorithms with systolic array architectures, suitable for high-throughput-rate and VLSI implementations of space-time filtering and system identification problems. The geometrical derivation given is unique in that no assumption is made concerning the rank of the sample data correlation matrix. This method utilizes and extends the concept of oblique projections, as used previously in the derivations of the least-squares lattice algorithms. Exponentially weighted least-squares criteria are considered for both sliding and growing memory.

Application of Seismic Array Processing to Tsunami Early Warning

NASA Astrophysics Data System (ADS)

An, C.; Meng, L.

2015-12-01

Tsunami wave predictions of the current tsunami warning systems rely on accurate earthquake source inversions of wave height data. They are of limited effectiveness for the near-field areas since the tsunami waves arrive before data are collected. Recent seismic and tsunami disasters have revealed the need for early warning to protect near-source coastal populations. In this work we developed the basis for a tsunami warning system based on rapid earthquake source characterisation through regional seismic array back-projections. We explored rapid earthquake source imaging using onshore dense seismic arrays located at regional distances on the order of 1000 km, which provides faster source images than conventional teleseismic back-projections. We implement this method in a simulated real-time environment, and analysed the 2011 Tohoku earthquake rupture with two clusters of Hi-net stations in Kyushu and Northern Hokkaido, and the 2014 Iquique event with the Earthscope USArray Transportable Array. The results yield reasonable estimates of rupture area, which is approximated by an ellipse and leads to the construction of simple slip models based on empirical scaling of the rupture area, seismic moment and average slip. The slip model is then used as the input of the tsunami simulation package COMCOT to predict the tsunami waves. In the example of the Tohoku event, the earthquake source model can be acquired within 6 minutes from the start of rupture and the simulation of tsunami waves takes less than 2 min, which could facilitate a timely tsunami warning. The predicted arrival time and wave amplitude reasonably fit observations. Based on this method, we propose to develop an automatic warning mechanism that provides rapid near-field warning for areas of high tsunami risk. The initial focus will be Japan, Pacific Northwest and Alaska, where dense seismic networks with the capability of real-time data telemetry and open data accessibility, such as the Japanese HiNet (>800 instruments) and the Earthscope USArray Transportable Array (~400 instruments), are established.

LUNASKA experiments using the Australia Telescope Compact Array to search for ultrahigh energy neutrinos and develop technology for the lunar Cherenkov technique

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

James, C. W.; Protheroe, R. J.; Ekers, R. D.

2010-02-15

We describe the design, performance, sensitivity and results of our recent experiments using the Australia Telescope Compact Array (ATCA) for lunar Cherenkov observations with a very wide (600 MHz) bandwidth and nanosecond timing, including a limit on an isotropic neutrino flux. We also make a first estimate of the effects of small-scale surface roughness on the effective experimental aperture, finding that contrary to expectations, such roughness will act to increase the detectability of near-surface events over the neutrino energy-range at which our experiment is most sensitive (though distortions to the time-domain pulse profile may make identification more difficult). The aimmore » of our 'Lunar UHE Neutrino Astrophysics using the Square Kilometre Array' (LUNASKA) project is to develop the lunar Cherenkov technique of using terrestrial radio telescope arrays for ultrahigh energy (UHE) cosmic ray (CR) and neutrino detection, and, in particular, to prepare for using the Square Kilometre Array (SKA) and its path-finders such as the Australian SKA Pathfinder (ASKAP) and the Low Frequency Array (LOFAR) for lunar Cherenkov experiments.« less

Partition resampling and extrapolation averaging: approximation methods for quantifying gene expression in large numbers of short oligonucleotide arrays.

PubMed

Goldstein, Darlene R

2006-10-01

Studies of gene expression using high-density short oligonucleotide arrays have become a standard in a variety of biological contexts. Of the expression measures that have been proposed to quantify expression in these arrays, multi-chip-based measures have been shown to perform well. As gene expression studies increase in size, however, utilizing multi-chip expression measures is more challenging in terms of computing memory requirements and time. A strategic alternative to exact multi-chip quantification on a full large chip set is to approximate expression values based on subsets of chips. This paper introduces an extrapolation method, Extrapolation Averaging (EA), and a resampling method, Partition Resampling (PR), to approximate expression in large studies. An examination of properties indicates that subset-based methods can perform well compared with exact expression quantification. The focus is on short oligonucleotide chips, but the same ideas apply equally well to any array type for which expression is quantified using an entire set of arrays, rather than for only a single array at a time. Software implementing Partition Resampling and Extrapolation Averaging is under development as an R package for the BioConductor project.

Development of infrared scene projectors for testing fire-fighter cameras

NASA Astrophysics Data System (ADS)

Neira, Jorge E.; Rice, Joseph P.; Amon, Francine K.

2008-04-01

We have developed two types of infrared scene projectors for hardware-in-the-loop testing of thermal imaging cameras such as those used by fire-fighters. In one, direct projection, images are projected directly into the camera. In the other, indirect projection, images are projected onto a diffuse screen, which is then viewed by the camera. Both projectors use a digital micromirror array as the spatial light modulator, in the form of a Micromirror Array Projection System (MAPS) engine having resolution of 800 x 600 with mirrors on a 17 micrometer pitch, aluminum-coated mirrors, and a ZnSe protective window. Fire-fighter cameras are often based upon uncooled microbolometer arrays and typically have resolutions of 320 x 240 or lower. For direct projection, we use an argon-arc source, which provides spectral radiance equivalent to a 10,000 Kelvin blackbody over the 7 micrometer to 14 micrometer wavelength range, to illuminate the micromirror array. For indirect projection, an expanded 4 watt CO II laser beam at a wavelength of 10.6 micrometers illuminates the micromirror array and the scene formed by the first-order diffracted light from the array is projected onto a diffuse aluminum screen. In both projectors, a well-calibrated reference camera is used to provide non-uniformity correction and brightness calibration of the projected scenes, and the fire-fighter cameras alternately view the same scenes. In this paper, we compare the two methods for this application and report on our quantitative results. Indirect projection has an advantage of being able to more easily fill the wide field of view of the fire-fighter cameras, which typically is about 50 degrees. Direct projection more efficiently utilizes the available light, which will become important in emerging multispectral and hyperspectral applications.

BRDF-dependent accuracy of array-projection-based 3D sensors.

PubMed

Heist, Stefan; Kühmstedt, Peter; Tünnermann, Andreas; Notni, Gunther

2017-03-10

In order to perform high-speed three-dimensional (3D) shape measurements with structured light systems, high-speed projectors are required. One possibility is an array projector, which allows pattern projection at several tens of kilohertz by switching on and off the LEDs of various slide projectors. The different projection centers require a separate analysis, as the intensity received by the cameras depends on the projection direction and the object's bidirectional reflectance distribution function (BRDF). In this contribution, we investigate the BRDF-dependent errors of array-projection-based 3D sensors and propose an error compensation process.

Astronomical Data Processing Using SciQL, an SQL Based Query Language for Array Data

NASA Astrophysics Data System (ADS)

Zhang, Y.; Scheers, B.; Kersten, M.; Ivanova, M.; Nes, N.

2012-09-01

SciQL (pronounced as ‘cycle’) is a novel SQL-based array query language for scientific applications with both tables and arrays as first class citizens. SciQL lowers the entrance fee of adopting relational DBMS (RDBMS) in scientific domains, because it includes functionality often only found in mathematics software packages. In this paper, we demonstrate the usefulness of SciQL for astronomical data processing using examples from the Transient Key Project of the LOFAR radio telescope. In particular, how the LOFAR light-curve database of all detected sources can be constructed, by correlating sources across the spatial, frequency, time and polarisation domains.

Searching for optical transients in real-time : the RAPTOR experiment /.

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

Vestrand, W. T.; Borozdin, K. N.; Brumby, Steven P.

2002-01-01

A rich, but relatively unexplored, region in optical astronomy is the study of transients with durations of less than a day. We describe a wide-field optical monitoring system, RAPTOR, which is designed to identify and make follow-up observations of optical transients in real-time. The system is composed of an array of telescopes that continuously monitor about 1500 square degrees of the sky for transients down to about 12' magnitude in 60 seconds and a central fovea telescope that can reach 16{approx}m' agnitude in 60 seconds. Coupled to the telescope array is a real-time data analysis pipeline that is designed tomore » identify transients on timescales of seconds. In a manner analogous to human vision, the entire array is mounted on a rapidly slewing robotic mount so that the fovea of the array can be rapidly directed at transients identified by the wide-field system. The goal of the project is to develop a ground-based optical system that can reliably identify transients in real-time and ultimately generate alerts with source locations to enable follow-up observations wilh other, larger, telescopes.« less

Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

NASA Technical Reports Server (NTRS)

Hoffman, David J.; Scheiman, David A.

1996-01-01

The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

Seismic Strong Motion Array Project (SSMAP) to Record Future Large Earthquakes in the Nicoya Peninsula area, Costa Rica

NASA Astrophysics Data System (ADS)

Simila, G.; McNally, K.; Quintero, R.; Segura, J.

2006-12-01

The seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica is composed of 10 13 sites including Geotech A900/A800 accelerographs (three-component), Ref-Teks (three- component velocity), and Kinemetric Episensors. The main objectives of the array are to: 1) record and locate strong subduction zone mainshocks [and foreshocks, "early aftershocks", and preshocks] in Nicoya Peninsula, at the entrance of the Nicoya Gulf, and in the Papagayo Gulf regions of Costa Rica, and 2) record and locate any moderate to strong upper plate earthquakes triggered by a large subduction zone earthquake in the above regions. Our digital accelerograph array has been deployed as part of our ongoing research on large earthquakes in conjunction with the Earthquake and Volcano Observatory (OVSICORI) at the Universidad Nacional in Costa Rica. The country wide seismographic network has been operating continuously since the 1980's, with the first earthquake bulletin published more than 20 years ago, in 1984. The recording of seismicity and strong motion data for large earthquakes along the Middle America Trench (MAT) has been a major research project priority over these years, and this network spans nearly half the time of a "repeat cycle" (50 years) for large (Ms 7.5- 7.7) earthquakes beneath the Nicoya Peninsula, with the last event in 1950. Our long time co-collaborators include the seismology group OVSICORI, with coordination for this project by Dr. Ronnie Quintero and Mr. Juan Segura. Numerous international investigators are also studying this region with GPS and seismic stations (US, Japan, Germany, Switzerland, etc.). Also, there are various strong motion instruments operated by local engineers, for building purposes and mainly concentrated in the population centers of the Central Valley. The major goal of our project is to contribute unique scientific information pertaining to a large subduction zone earthquake and its related seismic activity when the next large earthquake occurs in Nicoya. A centralized data base will be created within the main seismic network files at OVSICORI, with various local personnel working in teams that will be responsible to collect data within 3 days following a large mainshock.

Seismic Strong Motion Array Project (SSMAP) to Record Future Large Earthquakes in the Nicoya Peninsula area, Costa Rica

NASA Astrophysics Data System (ADS)

Simila, G.; Lafromboise, E.; McNally, K.; Quintereo, R.; Segura, J.

2007-12-01

The seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica is composed of 10 - 13 sites including Geotech A900/A800 accelerographs (three-component), Ref-Teks (three- component velocity), and Kinemetric Episensors. The main objectives of the array are to: 1) record and locate strong subduction zone mainshocks [and foreshocks, "early aftershocks", and preshocks] in Nicoya Peninsula, at the entrance of the Nicoya Gulf, and in the Papagayo Gulf regions of Costa Rica, and 2) record and locate any moderate to strong upper plate earthquakes triggered by a large subduction zone earthquake in the above regions. Our digital accelerograph array has been deployed as part of our ongoing research on large earthquakes in conjunction with the Earthquake and Volcano Observatory (OVSICORI) at the Universidad Nacional in Costa Rica. The country wide seismographic network has been operating continuously since the 1980's, with the first earthquake bulletin published more than 20 years ago, in 1984. The recording of seismicity and strong motion data for large earthquakes along the Middle America Trench (MAT) has been a major research project priority over these years, and this network spans nearly half the time of a "repeat cycle" (~ 50 years) for large (Ms ~ 7.5- 7.7) earthquakes beneath the Nicoya Peninsula, with the last event in 1950. Our long time co- collaborators include the seismology group OVSICORI, with coordination for this project by Dr. Ronnie Quintero and Mr. Juan Segura. The major goal of our project is to contribute unique scientific information pertaining to a large subduction zone earthquake and its related seismic activity when the next large earthquake occurs in Nicoya. We are now collecting a database of strong motion records for moderate sized events to document this last stage prior to the next large earthquake. A recent event (08/18/06; M=4.3) located 20 km northwest of Samara was recorded by two stations (Playa Carrillo and Nicoya) at distances of 25-30 km with maximum acceleration of 0.2g.

Direct phase projection and transcranial focusing of ultrasound for brain therapy.

PubMed

Pinton, Gianmarco F; Aubry, Jean-Francois; Tanter, Mickaël

2012-06-01

Ultrasound can be used to noninvasively treat the human brain with hyperthermia by focusing through the skull. To obtain an accurate focus, especially at high frequencies (>500 kHz), the phase of the transmitted wave must be modified to correct the aberrations introduced by the patient's individual skull morphology. Currently, three-dimensional finite-difference time-domain simulations are used to model a point source at the target. The outward-propagating wave crosses the measured representation of the human skull and is recorded at the therapy array transducer locations. The signal is then time reversed and experimentally transmitted back to its origin. These simulations are resource intensive and add a significant delay to treatment planning. Ray propagation is computationally efficient because it neglects diffraction and only describes two propagation parameters: the wave's direction and the phase. We propose a minimal method that is based only on the phase. The phase information is projected from the external skull surface to the array locations. This replaces computationally expensive finite-difference computations with an almost instantaneous direct phase projection calculation. For the five human skull samples considered, the phase distribution outside of the skull is shown to vary by less than λ/20 as it propagates over a 5 cm distance and the validity of phase projection is established over these propagation distances. The phase aberration introduced by the skull is characterized and is shown to have a good correspondence with skull morphology. The shape of this aberration is shown to have little variation with propagation distance. The focusing quality with the proposed phase-projection algorithm is shown to be indistinguishable from the gold-standard full finite-difference simulation. In conclusion, a spherical wave that is aberrated by the skull has a phase propagation that can be accurately described as radial, even after it has been distorted. By combining finite-difference simulations with a phase-projection algorithm, the time required for treatment planning is significantly reduced. The correlation length of the phase is used to validate the algorithm and it can also be used to provide guiding parameters for clinical array transducer design in terms of transducer spacing and phase error.

Low-cost solar array project and Proceedings of the 15th Project Integration Meeting

NASA Technical Reports Server (NTRS)

1980-01-01

Progress made by the Low-Cost Solar Array Project during the period December 1979 to April 1980 is described. Project analysis and integration, technology development in silicon material, large area silicon sheet and encapsulation, production process and equipment development, engineering, and operation are included.

HIGH-FIDELITY RADIO ASTRONOMICAL POLARIMETRY USING A MILLISECOND PULSAR AS A POLARIZED REFERENCE SOURCE

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

Van Straten, W., E-mail: vanstraten.willem@gmail.com

2013-01-15

A new method of polarimetric calibration is presented in which the instrumental response is derived from regular observations of PSR J0437-4715 based on the assumption that the mean polarized emission from this millisecond pulsar remains constant over time. The technique is applicable to any experiment in which high-fidelity polarimetry is required over long timescales; it is demonstrated by calibrating 7.2 years of high-precision timing observations of PSR J1022+1001 made at the Parkes Observatory. Application of the new technique followed by arrival time estimation using matrix template matching yields post-fit residuals with an uncertainty-weighted standard deviation of 880 ns, two timesmore » smaller than that of arrival time residuals obtained via conventional methods of calibration and arrival time estimation. The precision achieved by this experiment yields the first significant measurements of the secular variation of the projected semimajor axis, the precession of periastron, and the Shapiro delay; it also places PSR J1022+1001 among the 10 best pulsars regularly observed as part of the Parkes Pulsar Timing Array (PPTA) project. It is shown that the timing accuracy of a large fraction of the pulsars in the PPTA is currently limited by the systematic timing error due to instrumental polarization artifacts. More importantly, long-term variations of systematic error are correlated between different pulsars, which adversely affects the primary objectives of any pulsar timing array experiment. These limitations may be overcome by adopting the techniques presented in this work, which relax the demand for instrumental polarization purity and thereby have the potential to reduce the development cost of next-generation telescopes such as the Square Kilometre Array.« less

Wake acoustic analysis and image decomposition via beamforming of microphone signal projections on wavelet subspaces

DOT National Transportation Integrated Search

2006-05-08

This paper describes the integration of wavelet analysis and time-domain beamforming : of microphone array output signals for analyzing the acoustic emissions from airplane : generated wake vortices. This integrated process provides visual and quanti...

NEPTUNE: an under-sea plate scale observatory

NASA Technical Reports Server (NTRS)

Beauchamp, P. M.; Heath, G. R.; Maffei, A.; Chave, A.; Howe, B.; Wilcock, W.; Delaney, J.; Kirkham, H.

2002-01-01

The NEPTUNE project will establish a linked array of undersea observatories on the Juan de Fuca tectonic plate. This observatory will provide a new kind of research platform for real-time, long-term, plate-scale studies in the ocean and Earth sciences.

Optic probe for multiple angle image capture and optional stereo imaging

DOEpatents

Malone, Robert M.; Kaufman, Morris I.

2016-11-29

A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

Flat Plate Solar Array Project: Proceedings of the 20th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1982-01-01

Progress made by the Flat-Plate Solar Array Project during the period November 1981 to April 1982 is reported. Project analysis and integration, technology research in silicon material, large-area silicon sheet and environmental isolation, cell and module formation, engineering sciences, and module performance and failure analysis are covered.

Recent advances in a linear micromirror array for high-resolution projection

NASA Astrophysics Data System (ADS)

Picard, Francis; Doucet, Michel; Niall, Keith K.; Larouche, Carl; Savard, Maxime; Crisan, Silviu; Thibault, Simon; Jerominek, Hubert

2004-05-01

The visual displays of contemporary military flight simulators lack adequate definition to represent scenes in basic fast-jet fighter tasks. For example, air-to-air and air-to-ground targets are not projected with sufficient contrast and resolution for a pilot to perceive aspect, aspect rate and object detail at real world slant ranges. Simulator display geometries require the development of ultra-high resolution projectors with greater than 20 megapixel resolution at 60 Hz frame rate. A new micromirror device has been developed to address this requirement; it is able to modulate light intensity in an analog fashion with switching times shorter than 5 μs. When combined with a scanner, a laser and Schlieren optics, a linear array of these flexible micromirrors can display images composed of thousands of lines at a frame rate of 60 Hz. Recent results related to evaluation of this technology for high resolution projection are presented. Alternate operation modes for light modulation with flexible micromirrors are proposed. The related importance of controlling the residual micromirror curvature is discussed and results of experiments investigating the use of the deposition pressure to achieve such control are reported. Moreover, activities aiming at minimizing the micromirror response time and, so doing, maximizing the number of image columns per image frame are discussed. Finally, contrast measurement and estimate of the contrast limit achievable with the flexible micromirror technology are presented. All reported activities support the development of a fully addressable 2000-element micromirror array.

Methods of Real Time Image Enhancement of Flash LIDAR Data and Navigating a Vehicle Using Flash LIDAR Data

NASA Technical Reports Server (NTRS)

Vanek, Michael D. (Inventor)

2014-01-01

A method for creating a digital elevation map ("DEM") from frames of flash LIDAR data includes generating a first distance R(sub i) from a first detector i to a first point on a surface S(sub i). After defining a map with a mesh THETA having cells k, a first array S(k), a second array M(k), and a third array D(k) are initialized. The first array corresponds to the surface, the second array corresponds to the elevation map, and the third array D(k) receives an output for the DEM. The surface is projected onto the mesh THETA, so that a second distance R(sub k) from a second point on the mesh THETA to the detector can be found. From this, a height may be calculated, which permits the generation of a digital elevation map. Also, using sequential frames of flash LIDAR data, vehicle control is possible using an offset between successive frames.

Comprehensive performance comparison of high-resolution array platforms for genome-wide Copy Number Variation (CNV) analysis in humans.

PubMed

Haraksingh, Rajini R; Abyzov, Alexej; Urban, Alexander Eckehart

2017-04-24

High-resolution microarray technology is routinely used in basic research and clinical practice to efficiently detect copy number variants (CNVs) across the entire human genome. A new generation of arrays combining high probe densities with optimized designs will comprise essential tools for genome analysis in the coming years. We systematically compared the genome-wide CNV detection power of all 17 available array designs from the Affymetrix, Agilent, and Illumina platforms by hybridizing the well-characterized genome of 1000 Genomes Project subject NA12878 to all arrays, and performing data analysis using both manufacturer-recommended and platform-independent software. We benchmarked the resulting CNV call sets from each array using a gold standard set of CNVs for this genome derived from 1000 Genomes Project whole genome sequencing data. The arrays tested comprise both SNP and aCGH platforms with varying designs and contain between ~0.5 to ~4.6 million probes. Across the arrays CNV detection varied widely in number of CNV calls (4-489), CNV size range (~40 bp to ~8 Mbp), and percentage of non-validated CNVs (0-86%). We discovered strikingly strong effects of specific array design principles on performance. For example, some SNP array designs with the largest numbers of probes and extensive exonic coverage produced a considerable number of CNV calls that could not be validated, compared to designs with probe numbers that are sometimes an order of magnitude smaller. This effect was only partially ameliorated using different analysis software and optimizing data analysis parameters. High-resolution microarrays will continue to be used as reliable, cost- and time-efficient tools for CNV analysis. However, different applications tolerate different limitations in CNV detection. Our study quantified how these arrays differ in total number and size range of detected CNVs as well as sensitivity, and determined how each array balances these attributes. This analysis will inform appropriate array selection for future CNV studies, and allow better assessment of the CNV-analytical power of both published and ongoing array-based genomics studies. Furthermore, our findings emphasize the importance of concurrent use of multiple analysis algorithms and independent experimental validation in array-based CNV detection studies.

GNSS Space-Time Interference Mitigation and Attitude Determination in the Presence of Interference Signals

PubMed Central

Daneshmand, Saeed; Jahromi, Ali Jafarnia; Broumandan, Ali; Lachapelle, Gérard

2015-01-01

The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios. PMID:26016909

GNSS space-time interference mitigation and attitude determination in the presence of interference signals.

PubMed

Daneshmand, Saeed; Jahromi, Ali Jafarnia; Broumandan, Ali; Lachapelle, Gérard

2015-05-26

The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios.

Dynamic application of microprojection arrays to skin induces circulating protein extravasation for enhanced biomarker capture and detection.

PubMed

Coffey, Jacob W; Meliga, Stefano C; Corrie, Simon R; Kendall, Mark A F

2016-04-01

Surface modified microprojection arrays are a needle-free alternative to capture circulating biomarkers from the skin in vivo for diagnosis. The concentration and turnover of biomarkers in the interstitial fluid, however, may limit the amount of biomarker that can be accessed by microprojection arrays and ultimately their capture efficiency. Here we report that microprojection array insertion induces protein extravasation from blood vessels and increases the concentration of biomarkers in skin, which can synergistically improve biomarker capture. Regions of blood vessels in skin were identified in the upper dermis and subcutaneous tissue by multi-photon microscopy. Insertion of microprojection array designs with varying projection length (40-190 μm), density (5000-20,408 proj.cm(-2)) and array size (4-36 mm(2)) did not affect the degree of extravasation. Furthermore, the location of extravasated protein did not correlate with projection penetration to these highly vascularised regions, suggesting extravasation was not caused by direct puncture of blood vessels. Biomarker extravasation was also induced by dynamic application of flat control surfaces, and varied with the impact velocity, further supporting this conclusion. The extravasated protein distribution correlated well with regions of high mechanical stress generated during insertion, quantified by finite element models. Using this approach to induce extravasation prior to microprojection array-based biomarker capture, anti-influenza IgG was captured within a 2 min application time, demonstrating that extravasation can lead to rapid biomarker sampling and significantly improved microprojection array capture efficiency. These results have broad implications for the development of transdermal devices that deliver to and sample from the skin. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Photogrammetric Assessment of the Hubble Space Telescope Solar Arrays During the Second Servicing Mission

NASA Technical Reports Server (NTRS)

Sapp, C. A.; Dragg, J. L.; Snyder, M. W.; Gaunce, M. T.; Decker, J. E.

1998-01-01

This report documents the photogrammetric assessment of the Hubble Space Telescope (HST) solar arrays conducted by the NASA c Center Image Science and Analysis Group during Second Servicing Mission 2 (SM-2) on STS-82 in February 1997. Two type solar array analyses were conducted during the mission using Space Shuttle payload bay video: (1) measurement of solar array motion due to induced loads, and (2) measurement of the solar array static or geometric twist caused by the cumulative array loading. The report describes pre-mission planning and analysis technique development activities conducted to acquire and analyze solar array imagery data during SM-2. This includes analysis of array motion obtained during SM-1 as a proof-of-concept of the SM-2 measurement techniques. The report documents the results of real-time analysis conducted during the mission and subsequent analysis conducted post-flight. This report also provides a summary of lessons learned on solar array imagery analysis from SM-2 and recommendations for future on-orbit measurements applicable to HST SM-3 and to the International Space Station. This work was performed under the direction of the Goddard Space Flight Center HST Flight Systems and Servicing Project.

INVERSION OF SOURCE TIME FUNCTION USING BOREHOLE ARRAY SONIC WAVEFORMS. (R825225)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

SCAMP: Rapid Focused Sonic Boom Waypoint Flight Planning Methods, Execution, and Results

NASA Technical Reports Server (NTRS)

Haering, Edward A., Jr.; Cliatt, Larry J., II; Delaney, Michael M., Jr.; Plotkin, Kenneth J.; Maglieri, Domenic J.; Brown, Jacob C.

2012-01-01

Successful execution of the flight phase of the Superboom Caustic Analysis and Measurement Project (SCAMP) required accurate placement of focused sonic booms on an array of prepositioned ground sensors. While the array was spread over a 10,000-ft-long area, this is a relatively small region when considering the speed of a supersonic aircraft and sonic boom ray path variability due to shifting atmospheric conditions and aircraft trajectories. Another requirement of the project was to determine the proper position for a microphone-equipped motorized glider to intercept the sonic boom caustic, adding critical timing to the constraints. Variability in several inputs to these calculations caused some shifts of the focus away from the optimal location. Reports of the sonic booms heard by persons positioned amongst the array were used to shift the focus closer to the optimal location for subsequent passes. This paper describes the methods and computations used to place the focused sonic boom on the SCAMP array and gives recommendations for their accurate placement by future quiet supersonic aircraft. For the SCAMP flights, 67% of the foci were placed on the ground array with measured positions within a few thousand feet of computed positions. Among those foci with large caustic elevation angles, 96% of foci were placed on the array, and measured positions were within a few hundred feet of computed positions. The motorized glider captured sonic booms on 59% of the passes when the instrumentation was operating properly.

Mitigating artifacts in back-projection source imaging with implications for frequency-dependent properties of the Tohoku-Oki earthquake

NASA Astrophysics Data System (ADS)

Meng, Lingsen; Ampuero, Jean-Paul; Luo, Yingdi; Wu, Wenbo; Ni, Sidao

2012-12-01

Comparing teleseismic array back-projection source images of the 2011 Tohoku-Oki earthquake with results from static and kinematic finite source inversions has revealed little overlap between the regions of high- and low-frequency slip. Motivated by this interesting observation, back-projection studies extended to intermediate frequencies, down to about 0.1 Hz, have suggested that a progressive transition of rupture properties as a function of frequency is observable. Here, by adapting the concept of array response function to non-stationary signals, we demonstrate that the "swimming artifact", a systematic drift resulting from signal non-stationarity, induces significant bias on beamforming back-projection at low frequencies. We introduce a "reference window strategy" into the multitaper-MUSIC back-projection technique and significantly mitigate the "swimming artifact" at high frequencies (1 s to 4 s). At lower frequencies, this modification yields notable, but significantly smaller, artifacts than time-domain stacking. We perform extensive synthetic tests that include a 3D regional velocity model for Japan. We analyze the recordings of the Tohoku-Oki earthquake at the USArray and at the European array at periods from 1 s to 16 s. The migration of the source location as a function of period, regardless of the back-projection methods, has characteristics that are consistent with the expected effect of the "swimming artifact". In particular, the apparent up-dip migration as a function of frequency obtained with the USArray can be explained by the "swimming artifact". This indicates that the most substantial frequency-dependence of the Tohoku-Oki earthquake source occurs at periods longer than 16 s. Thus, low-frequency back-projection needs to be further tested and validated in order to contribute to the characterization of frequency-dependent rupture properties.

The EEE Project: a sparse array of telescopes for the measurement of cosmic ray muons

NASA Astrophysics Data System (ADS)

La Rocca, P.; Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccetti, F.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; Liciulli, F.; Maggiora, A.; Maragoto Rodriguez, O.; Maron, G.; Martelli, B.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M.; Paoletti, R.; Park, W.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Rizzi, M.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Visnyei, O. B.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

2016-12-01

The Extreme Energy Events (EEE) Project is meant to be the most extensive experiment to detect secondary cosmic particles in Italy. To this aim, more than 50 telescopes have been built at CERN and installed in high schools distributed all over the Italian territory. Each EEE telescope comprises three large area Multigap Resistive Plate Chambers (MRPCs) and is capable of reconstructing the trajectories of the charged particles traversing it with a good angular resolution. The excellent performance of the EEE telescopes allows a large variety of studies, from measuring the local muon flux in a single telescope, to detecting extensive air showers producing time correlations in the same metropolitan area, to searching for large-scale correlations between showers detected in telescopes tens, hundreds or thousands of kilometers apart. In addition to its scientific goal, the EEE Project also has an educational and outreach objective, its aim being to motivate young people by involving them directly in a real experiment. High school students and teachers are involved in the construction, testing and start-up of the EEE telescope in their school, then in its maintenance and data-acquisition, and later in the analysis of the data. During the last couple of years a great boost has been given to the EEE Project through the organization of simultaneous and centralized data taking with the whole telescope array. The raw data from all telescopes are transferred to CNAF (Bologna), where they are reconstructed and stored. The data are currently being analyzed, looking at various topics: variation of the rate of cosmic muons with time, upward going muons, muon lifetime, search for anisotropies in the muon angular distribution and for time coincidences between stations. In this paper an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array is also presented by showing the most recent physics results.

Hydrogen from renewable energy - Photovoltaic/water electrolysis as an exemplary approach

NASA Technical Reports Server (NTRS)

Sprafka, R. J.; Tison, R. R.; Escher, W. J. D.

1984-01-01

A feasibility study has been conducted for a NASA Kennedy Space Center liquid hydrogen/liquid oxygen production facility using solar cell arrays as the power source for electrolysis. The 100 MW output of the facility would be split into 67.6 and 32 MW portions for electrolysis and liquefaction, respectively. The solar cell array would cover 1.65 sq miles, and would be made up of 249 modular 400-kW arrays. Hydrogen and oxygen are generated at either dispersed or centralized water electrolyzers. The yearly hydrogen output is projected to be 5.76 million lbs, with 8 times that much oxygen; these fuel volumes can support approximately 18 Space Shuttle launches/year.

Feasibility study, software design, layout and simulation of a two-dimensional Fast Fourier Transform machine for use in optical array interferometry

NASA Technical Reports Server (NTRS)

Boriakoff, Valentin

1994-01-01

The goal of this project was the feasibility study of a particular architecture of a digital signal processing machine operating in real time which could do in a pipeline fashion the computation of the fast Fourier transform (FFT) of a time-domain sampled complex digital data stream. The particular architecture makes use of simple identical processors (called inner product processors) in a linear organization called a systolic array. Through computer simulation the new architecture to compute the FFT with systolic arrays was proved to be viable, and computed the FFT correctly and with the predicted particulars of operation. Integrated circuits to compute the operations expected of the vital node of the systolic architecture were proven feasible, and even with a 2 micron VLSI technology can execute the required operations in the required time. Actual construction of the integrated circuits was successful in one variant (fixed point) and unsuccessful in the other (floating point).

Prey-sensing and orientational behaviors of sand scorpions

NASA Astrophysics Data System (ADS)

Brownell, Philip

2000-03-01

Sand scorpions use exquisitely sensitive vibrational and chemosensory systems to locate prey and identify prospective mates active on the sand surface. Prey location is determined by input to a static array of 8 vibration-sensitive receptors, each responding as phase-locked accelerometers to compressional and surface waves conducted through sand. Angular orientation of the target is determined from passing surface (Rayleigh) waves, target distance possibly from the time delay between arrival of compressional and surface waves. For localization and identification of prospective mates, male scorpions use sexually dimorphic chemosensory appendages, the pectines, which are swept over a static stimulus field (chemical trail deposited on sand). These organs support a 2D array of closely-spaced (freq = 100/mm) sensilla containing more than 10^6 neurons, all projecting with great topographic precision to the central nervous system. Movement of this sensory array over a static stimulus field creates timing within the sensory signal. The potential importance of timing as a means of increasing sensitivity and selectivity of sensory response in two distinctly different modes is discussed.

System engineering and science projects: lessons from MeerKAT

NASA Astrophysics Data System (ADS)

Kapp, Francois

2016-08-01

The Square Kilometre Array (SKA) is a large science project planning to commence construction of the world's largest Radio Telescope after 2018. MeerKAT is one of the precursor projects to the SKA, based on the same site that will host the SKA Mid array in the central Karoo area of South Africa. From the perspective of signal processing hardware development, we analyse the challenges that MeerKAT encountered and extrapolate them to SKA in order to prepare the System Engineering and Project Management methods that could contribute to a successful completion of SKA. Using the MeerKAT Digitiser, Correlator/Beamformer and Time and Frequency Reference Systems as an example, we will trace the risk profile and subtle differences in engineering approaches of these systems over time and show the effects of varying levels of System Engineering rigour on the evolution of their risk profiles. It will be shown that the most rigorous application of System Engineering discipline resulted in the most substantial reduction in risk over time. Since the challenges faced by SKA are not limited to that of MeerKAT, we also look into how that translates to a system development where there is substantial complexity in both the created system as well as the creating system. Since the SKA will be designed and constructed by consortia made up from the ten member countries, there are many additional complexities to the organisation creating the system - a challenge the MeerKAT project did not encounter. Factors outside of engineering, for instance procurement models and political interests, also play a more significant role, and add to the project risks of SKA when compared to MeerKAT.

Development of an Advanced Hydraulic Fracture Mapping System

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

Norm Warpinski; Steve Wolhart; Larry Griffin

The project to develop an advanced hydraulic fracture mapping system consisted of both hardware and analysis components in an effort to build, field, and analyze combined data from tiltmeter and microseismic arrays. The hardware sections of the project included: (1) the building of new tiltmeter housings with feedthroughs for use in conjunction with a microseismic array, (2) the development of a means to use separate telemetry systems for the tilt and microseismic arrays, and (3) the selection and fabrication of an accelerometer sensor system to improve signal-to-noise ratios. The analysis sections of the project included a joint inversion for analysismore » and interpretation of combined tiltmeter and microseismic data and improved methods for extracting slippage planes and other reservoir information from the microseisms. In addition, testing was performed at various steps in the process to assess the data quality and problems/issues that arose during various parts of the project. A prototype array was successfully tested and a full array is now being fabricated for industrial use.« less

Michrohole Arrays Drilled with Advanced Abrasive Slurry Jet Technology to Efficiently Exploit Enhanced Geothermal Systems

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

Oglesby, Kenneth; Finsterle, Stefan; Zhang, Yingqi

2014-03-12

This project had two major areas of research for Engineered/ Enhanced Geothermal System (EGS) development - 1) study the potential benefits from using microholes (i.e., bores with diameters less than 10.16 centimeters/ 4 inches) and 2) study FLASH ASJ to drill/ install those microbores between a well and a fracture system. This included the methods and benefits of drilling vertical microholes for exploring the EGS reservoir and for installing multiple (forming an array of) laterals/ directional microholes for creating the in-reservoir heat exchange flow paths. Significant benefit was found in utilizing small microbore sized connecting bores for EGS efficiency andmore » project life. FLASH ASJ was deemed too complicated to optimally work in such deep reservoirs at this time.« less

MIGHTEE: The MeerKAT International GHz Tiered Extragalactic Exploration

NASA Astrophysics Data System (ADS)

Taylor, A. Russ; Jarvis, Matt

2017-05-01

The MeerKAT telescope is the precursor of the Square Kilometre Array mid-frequency dish array to be deployed later this decade on the African continent. MIGHTEE is one of the MeerKAT large survey projects designed to pathfind SKA key science in cosmology and galaxy evolution. Through a tiered radio continuum deep imaging project including several fields totaling 20 square degrees to microJy sensitivities and an ultra-deep image of a single 1 square degree field of view, MIGHTEE will explore dark matter and large scale structure, the evolution of galaxies, including AGN activity and star formation as a function of cosmic time and environment, the emergence and evolution of magnetic fields in galaxies, and the magnetic counter part to large scale structure of the universe.

Performance of CATIROC: ASIC for smart readout of large photomultiplier arrays

NASA Astrophysics Data System (ADS)

Blin, S.; Callier, S.; Conforti Di Lorenzo, S.; Dulucq, F.; De La Taille, C.; Martin-Chassard, G.; Seguin-Moreau, N.

2017-03-01

CATIROC (Charge And Time Integrated Read Out Chip) is a complete read-out chip manufactured in AustriaMicroSystem (AMS) SiGe 0.35 μm technology, designed to read arrays of 16 photomultipliers (PMTs). It is an upgraded version of PARISROC2 [1] designed in 2010 in the context of the PMm2 (square meter PhotoMultiplier) project [2]. CATIROC is a SoC (System on Chip) that processes analog signals up to the digitization and sparsification to reduce the cost and cable number. The ASIC is composed of 16 independent channels that work in triggerless mode, auto-triggering on the single photo-electron. It provides a charge measurement up to 400 photoelectrons (70 pC) on two scales of 10 bits and a timing information with an accuracy of 200 ps rms. The ASIC was sent for fabrication in February 2015 and then received in September 2015. It is a good candidate for two Chinese projects (LHAASO and JUNO). The architecture and the measurements will be detailed in the paper.

Indium phosphide solar cells - Status and prospects for use in space

NASA Technical Reports Server (NTRS)

Weinberg, I.; Brinker, D. J.

1986-01-01

The current status of indium phosphide cell research is reviewed and state of the art efficiencies compared to those of GaAs and Si. It is shown that the radiation resistance of InP cells is superior to that of either GaAs or Si under 1 MeV electron and 10 MeV proton irradiation. Using lightweight blanket technology, a SEP array structure and projected cell efficiencies, array specific powers are obtained for all three cell types. Array performance is calculated as a function of time in orbit. The results indicate that arrays using InP cells can outperform those using GaAs or Si in orbits where radiation is a significant cell degradation factor. It is concluded that InP solar cells are excellent prospects for future use in the space radiation environment.

Indium phosphide solar cells: status and prospects for use in space

NASA Technical Reports Server (NTRS)

Weinberg, I.; Brinker, D. J.

1986-01-01

The current status of indium phosphide cell research is reviewed and state of the art efficiencies compared to those of GaAs and Si. It is shown that the radiation resistance of InP cells is superior to that of either GaAs or Si under 1 MeV electron and 10 MeV proton irradiation. Using lightweight blanket technology, a SEP array structure and projected cell efficiencies, array specific powers are obtained for all three cell types. Array performance is calculated as a function of time in orbit. The results indicate that arrays using InP cells can outperform those using GaAs or Si in orbits where radiation is a significant cell degradation factor. It is concluded that InP solar cells are excellent prospects for future use in the space radiation environment.

Low-cost Solar Array (LSA) project

NASA Technical Reports Server (NTRS)

1978-01-01

Progress made by the Low-Cost Silicon Solar Array Project during the period January through March 1978 is reported. It includes task reports on silicon material processing, large-area silicon sheet development, encapsulation materials testing and development, project engineering and operations, and manufacturing techniques, plus the steps taken to integrate these efforts.

Photoacoustic Imaging of Animals with an Annular Transducer Array

NASA Astrophysics Data System (ADS)

Yang, Di-Wu; Zhou, Zhi-Bin; Zeng, Lv-Ming; Zhou, Xin; Chen, Xing-Hui

2014-07-01

A photoacoustic system with an annular transducer array is presented for rapid, high-resolution photoacoustic tomography of animals. An eight-channel data acquisition system is applied to capture the photoacoustic signals by using multiplexing and the total time of data acquisition and transferring is within 3 s. A limited-view filtered back projection algorithm is used to reconstruct the photoacoustic images. Experiments are performed on a mouse head and a rabbit head and clear photoacoustic images are obtained. The experimental results demonstrate that this imaging system holds the potential for imaging the human brain.

Flat-plate solar array project of the US Department of Energy's National Photovoltaics Program: Ten years of progress

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

The Flat-Plate Solar Array (FSA) Project, a Government-sponsored photovoltaics project, was initiated in January 1975 (previously named the Low-Cost Silicon Solar Array Project) to stimulate the development of PV systems for widespread use. Its goal then was to develop PV modules with 10% efficiency, a 20-year lifetime, and a selling price of $0.50 per peak watt of generating capacity (1975 dollars). It was recognized that cost reduction of PV solar-cell and module manufacturing was the key achievement needed if PV power systems were to be economically competitive for large-scale terrestrial use.

Comparative efficiency analysis of fiber-array and conventional beam director systems in volume turbulence.

PubMed

Vorontsov, Mikhail; Filimonov, Grigory; Ovchinnikov, Vladimir; Polnau, Ernst; Lachinova, Svetlana; Weyrauch, Thomas; Mangano, Joseph

2016-05-20

The performance of two prominent laser beam projection system types is analyzed through wave-optics numerical simulations for various atmospheric turbulence conditions, propagation distances, and adaptive optics (AO) mitigation techniques. Comparisons are made between different configurations of both a conventional beam director (BD) using a monolithic-optics-based Cassegrain telescope and a fiber-array BD that uses an array of densely packed fiber collimators. The BD systems considered have equal input power and aperture diameters. The projected laser beam power inside the Airy size disk at the target plane is used as the performance metric. For the fiber-array system, both incoherent and coherent beam combining regimes are considered. We also present preliminary results of side-by-side atmospheric beam projection experiments over a 7-km propagation path using both the AO-enhanced beam projection system with a Cassegrain telescope and the coherent fiber-array BD composed of 21 densely packed fiber collimators. Both wave-optics numerical simulation and experimental results demonstrate that, for similar system architectures and turbulence conditions, coherent fiber-array systems are more efficient in mitigation of atmospheric turbulence effects and generation of a hit spot of the smallest possible size on a remotely located target.

Artificial intelligence for the CTA Observatory scheduler

NASA Astrophysics Data System (ADS)

Colomé, Josep; Colomer, Pau; Campreciós, Jordi; Coiffard, Thierry; de Oña, Emma; Pedaletti, Giovanna; Torres, Diego F.; Garcia-Piquer, Alvaro

2014-08-01

The Cherenkov Telescope Array (CTA) project will be the next generation ground-based very high energy gamma-ray instrument. The success of the precursor projects (i.e., HESS, MAGIC, VERITAS) motivated the construction of this large infrastructure that is included in the roadmap of the ESFRI projects since 2008. CTA is planned to start the construction phase in 2015 and will consist of two arrays of Cherenkov telescopes operated as a proposal-driven open observatory. Two sites are foreseen at the southern and northern hemispheres. The CTA observatory will handle several observation modes and will have to operate tens of telescopes with a highly efficient and reliable control. Thus, the CTA planning tool is a key element in the control layer for the optimization of the observatory time. The main purpose of the scheduler for CTA is the allocation of multiple tasks to one single array or to multiple sub-arrays of telescopes, while maximizing the scientific return of the facility and minimizing the operational costs. The scheduler considers long- and short-term varying conditions to optimize the prioritization of tasks. A short-term scheduler provides the system with the capability to adapt, in almost real-time, the selected task to the varying execution constraints (i.e., Targets of Opportunity, health or status of the system components, environment conditions). The scheduling procedure ensures that long-term planning decisions are correctly transferred to the short-term prioritization process for a suitable selection of the next task to execute on the array. In this contribution we present the constraints to CTA task scheduling that helped classifying it as a Flexible Job-Shop Problem case and finding its optimal solution based on Artificial Intelligence techniques. We describe the scheduler prototype that uses a Guarded Discrete Stochastic Neural Network (GDSN), for an easy representation of the possible long- and short-term planning solutions, and Constraint Propagation techniques. A simulation platform, an analysis tool and different test case scenarios for CTA were developed to test the performance of the scheduler and are also described.

EGS hydraulic stimulation monitoring by surface arrays - location accuracy and completeness magnitude: the Basel Deep Heat Mining Project case study

NASA Astrophysics Data System (ADS)

Häge, Martin; Blascheck, Patrick; Joswig, Manfred

2013-01-01

The potential and limits of monitoring induced seismicity by surface-based mini arrays was evaluated for the hydraulic stimulation of the Basel Deep Heat Mining Project. This project aimed at the exploitation of geothermal heat from a depth of about 4,630 m. As reference for our results, a network of borehole stations by Geothermal Explorers Ltd. provided ground truth information. We utilized array processing, sonogram event detection and outlier-resistant, graphical jackknife location procedures to compensate for the decrease in signal-to-noise ratio at the surface. We could correctly resolve the NNW-SSE striking fault plane by relative master event locations. Statistical analysis of our catalog data resulted in M L 0.36 as completeness magnitude, but with significant day-to-night dependency. To compare to the performance of borehole data with M W 0.9 as completeness magnitude, we applied two methods for converting M L to M W which raised our M C to M W in the range of 0.99-1.13. Further, the b value for the duration of our measurement was calculated to 1.14 (related to M L), respectively 1.66 (related to M W), but changes over time could not be resolved from the error bars.

LIGHTWEIGHT INTEGRATED SOLAR ARRAY AND TRANSCEIVER

NASA Image and Video Library

2016-09-23

JOHN CARR, RIGHT, CO-PRINCIPAL INVESTIGATOR FOR NASA'S LIGHTWEIGHT INTEGRATED SOLAR ARRAY AND TRANSCEIVER PROJECT, TALKS WITH GREG LAUE, DIRECTOR OF AEROSPACE PRODUCTS FOR NEXOLVE, MANUFACTURER OF THE THIN-FILM TECHNOLOGY AND A PARTNER IN THE PROJECT.

Flat-plate solar array project. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Callaghan, W.; Mcdonald, R.

1986-01-01

In 1975, the U.S. Government contracted the Jet Propulsion Lab. to develop, by 1985, in conjunction with industry, the photovoltaics (PV) module and array technology required for widespread use of photovoltaics as a significant terrestrial energy source. As a result, a project that eventually became known as the Flat Plate Solar Array (FSA) Project was formed to manage an industry, university, and Government team to perform the necessary research and development. The original goals were to achieve widespread commercial use of PV modules and arrays through the development of technology that would allow them to be profitably sold for $1.07/peak watts (1985 dollars). A 10% module conversion efficiency and a 20 year lifetime were also goals. It is intended that the executive summary provide the means by which one can gain a perspective on 11 years of terrestrial photovoltaic research and development conducted by the FSA Project.

Spatial light modulator array with heat minimization and image enhancement features

DOEpatents

Jain, Kanti [Briarcliff Manor, NY; Sweatt, William C [Albuquerque, NM; Zemel, Marc [New Rochelle, NY

2007-01-30

An enhanced spatial light modulator (ESLM) array, a microelectronics patterning system and a projection display system using such an ESLM for heat-minimization and resolution enhancement during imaging, and the method for fabricating such an ESLM array. The ESLM array includes, in each individual pixel element, a small pixel mirror (reflective region) and a much larger pixel surround. Each pixel surround includes diffraction-grating regions and resolution-enhancement regions. During imaging, a selected pixel mirror reflects a selected-pixel beamlet into the capture angle of a projection lens, while the diffraction grating of the pixel surround redirects heat-producing unused radiation away from the projection lens. The resolution-enhancement regions of selected pixels provide phase shifts that increase effective modulation-transfer function in imaging. All of the non-selected pixel surrounds redirect all radiation energy away from the projection lens. All elements of the ESLM are fabricated by deposition, patterning, etching and other microelectronic process technologies.

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

Mosher, J.C.; Leahy, R.M.

A new method for source localization is described that is based on a modification of the well known multiple signal classification (MUSIC) algorithm. In classical MUSIC, the array manifold vector is projected onto an estimate of the signal subspace, but errors in the estimate can make location of multiple sources difficult. Recursively applied and projected (RAP) MUSIC uses each successively located source to form an intermediate array gain matrix, and projects both the array manifold and the signal subspace estimate into its orthogonal complement. The MUSIC projection is then performed in this reduced subspace. Using the metric of principal angles,more » the authors describe a general form of the RAP-MUSIC algorithm for the case of diversely polarized sources. Through a uniform linear array simulation, the authors demonstrate the improved Monte Carlo performance of RAP-MUSIC relative to MUSIC and two other sequential subspace methods, S and IES-MUSIC.« less

Radio Observations of the Ionosphere From an Imaging Array and a CubeSat

NASA Astrophysics Data System (ADS)

Isham, B.; Gustavsson, B.; Bullett, T. W.; Bergman, J. E. S.; Rincón-Charris, A.; Bruhn, F.; Funk, P.

2017-12-01

The ionosphere is a source of many radio emissions in the various low-frequency, medium-frequency, and high-frequency bands (0 to 30 MHz). In addition to natural radio emissions, artificial emissions can be stimulated using high-power radiowave ionospheric modification facilities. Two complementary projects are underway for the purpose of improving our knowledge of the processes of radio emissions from the ionosphere. One project is the Aguadilla radio array, located in northwestern Puerto Rico. The Aguadilla array is intended to produce 2 to 25 MHz radio images of the ionosphere, as well as to perform bistatic radar imaging of the ionosphere over Puerto Rico. The array will consist of multiple antenna elements, each of which is a single active (electromagnetically short) crossed electric dipole. The elements are arranged within a roughly 200 by 300-meter core array, in a semi-random pattern providing an optimal distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. In addition, several elements are arranged in a partial ring around the central core, providing a roughly four times expanded region in u-v space for improved image resolution and quality. Phase is maintained via cabled connections to a central location. A remote array is also being developed, in which phase is maintained between elements by through the use of GPS-disciplined rubidium clocks. The other project involves the GimmeRF radio instrument, designed for 0.3 to 30 MHz vector observation of the radio electric field, and planned for launch in 2020 on a CubeSat. The data rate that can be sustained by GimmeRF far exceeds any available communication strategy. By exploiting fast on-board computing and efficient artificial intelligence (AI) algorithms for analysis and data selection, the usage of the telemetry link can be optimized and value added to the mission. Radio images recorded by the radio array from below the ionosphere can be directly compared with the radio data received by GimmeRF in the topside ionosphere, with the goal of better understanding the geometry and therefore the mechanisms of the radio emission processes.

Monitoring hydrofrac-induced seismicity by surface arrays - the DHM-Project Basel case study

NASA Astrophysics Data System (ADS)

Blascheck, P.; Häge, M.; Joswig, M.

2012-04-01

The method "nanoseismic monitoring" was applied during the hydraulic stimulation at the Deep-Heat-Mining-Project (DHM-Project) Basel. Two small arrays in a distance of 2.1 km and 4.8 km to the borehole recorded continuously for two days. During this time more than 2500 seismic events were detected. The method of the surface monitoring of induced seismicity was compared to the reference which the hydrofrac monitoring presented. The latter was conducted by a network of borehole seismometers by Geothermal Explorers Limited. Array processing provides a outlier resistant, graphical jack-knifing localization method which resulted in a average deviation towards the reference of 850 m. Additionally, by applying the relative localization master-event method, the NNW-SSE strike direction of the reference was confirmed. It was shown that, in order to successfully estimate the magnitude of completeness as well as the b-value at the event rate and detection sensibility present, 3 h segments of data are sufficient. This is supported by two segment out of over 13 h of evaluated data. These segments were chosen so that they represent a time during the high seismic noise during normal working hours in daytime as well as the minimum anthropogenic noise at night. The low signal-to-noise ratio was compensated by the application of a sonogram event detection as well as a coincidence analysis within each array. Sonograms allow by autoadaptive, non-linear filtering to enhance signals whose amplitudes are just above noise level. For these events the magnitude was determined by the master-event method, allowing to compute the magnitude of completeness by the entire-magnitude-range method provided by the ZMAP toolbox. Additionally, the b-values were determined and compared to the reference values. An introduction to the method of "nanoseismic monitoring" will be given as well as the comparison to reference data in the Basel case study.

Compact intra-cavity frequency doubled line beam green laser by a laser diode array pumped

NASA Astrophysics Data System (ADS)

Yan, Boxia; Qi, Yan; Wang, Yanwei

2016-10-01

Compact, high power, and low-cost green laser light sources are needed in projection-related applications such as digital cinema, rear-projection television, simulators, and command and control stations. We report a LD array directly pumped intracavity SHG Nd:YVO4/PPMgLN laser without lens or waveguide in this letter. A compact 3.12 W green laser was demonstrated by intra-cavity frequency doubled using a PPMgLN bulk crystal by a 19-emitter LD array pumped(single bar), the conversion efficiency from input LD array was 9.2%. A line-beam output suitable for laser projectors was generated, which has the potential to be scalable to small volumes and low costs for laser projection displays.

Adaptive and mobile ground sensor array.

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

Holzrichter, Michael Warren; O'Rourke, William T.; Zenner, Jennifer

The goal of this LDRD was to demonstrate the use of robotic vehicles for deploying and autonomously reconfiguring seismic and acoustic sensor arrays with high (centimeter) accuracy to obtain enhancement of our capability to locate and characterize remote targets. The capability to accurately place sensors and then retrieve and reconfigure them allows sensors to be placed in phased arrays in an initial monitoring configuration and then to be reconfigured in an array tuned to the specific frequencies and directions of the selected target. This report reviews the findings and accomplishments achieved during this three-year project. This project successfully demonstrated autonomousmore » deployment and retrieval of a payload package with an accuracy of a few centimeters using differential global positioning system (GPS) signals. It developed an autonomous, multisensor, temporally aligned, radio-frequency communication and signal processing capability, and an array optimization algorithm, which was implemented on a digital signal processor (DSP). Additionally, the project converted the existing single-threaded, monolithic robotic vehicle control code into a multi-threaded, modular control architecture that enhances the reuse of control code in future projects.« less

Conceptual approach on harvesting PV dissipated heat for enhancing water evaporation

NASA Astrophysics Data System (ADS)

Latiff, N. Abdul; Ya'acob, M. E.; Yunos, Khairul Faezah Md.

2017-09-01

The fluctuating sun radiation in tropical climate conditions has significantly affected the output performance of the PV array and also processes related to direct-sun drying. Apart from this, the dissipated heat under PV array projected from photonic effects of generating electricity is currently wasted to the environment. This study shares some conceptual idea on a new approach for harvesting the dissipated heat energy from PV arrays for the purpose of enhancing water evaporation process. Field measurements for ambient temperature (Ta) and PV bottom surface temperature (FFb) are measured and recorded for calculating the evaporation rates at different condition in real time. The waste heat dissipated in this condition is proposed as a medium to increase evaporation thru speeding up the water condensation process. The significant increase of water evaporation rate based on Penman equation supports the idea of integration with landed PV array structures.

Plasmodium Genus Assay Transition to the Joint Biological Agent Identification and Diagnostic System (JBAIDS)

DTIC Science & Technology

2012-07-12

readily transferable to diverse real-time PCR instrumentation. These assays are used regularly for vector surveillance and are the primary...instrumentation ( FilmArray ) is under assessment. Assay oligonucleotide sequences and formulations are available for use in future joint projects...Plasmodium real-time PCR detection capability has been challenging. During 2006, the Division of Entomology, WRAIR designed and developed a

Estimation of the chemical rank for the three-way data: a principal norm vector orthogonal projection approach.

PubMed

Hong-Ping, Xie; Jian-Hui, Jiang; Guo-Li, Shen; Ru-Qin, Yu

2002-01-01

A new approach for estimating the chemical rank of the three-way array called the principal norm vector orthogonal projection method has been proposed. The method is based on the fact that the chemical rank of the three-way data array is equal to one of the column space of the unfolded matrix along the spectral or chromatographic mode. A vector with maximum Frobenius norm is selected among all the column vectors of the unfolded matrix as the principal norm vector (PNV). A transformation is conducted for the column vectors with an orthogonal projection matrix formulated by PNV. The mathematical rank of the column space of the residual matrix thus obtained should decrease by one. Such orthogonal projection is carried out repeatedly till the contribution of chemical species to the signal data is all deleted. At this time the decrease of the mathematical rank would equal that of the chemical rank, and the remaining residual subspace would entirely be due to the noise contribution. The chemical rank can be estimated easily by using an F-test. The method has been used successfully to the simulated HPLC-DAD type three-way data array and two real excitation-emission fluorescence data sets of amino acid mixtures and dye mixtures. The simulation with added relatively high level noise shows that the method is robust in resisting the heteroscedastic noise. The proposed algorithm is simple and easy to program with quite light computational burden.

New Opportunities in Decay Spectroscopy with the GRIFFIN and DESCANT Arrays

NASA Astrophysics Data System (ADS)

Bildstein, V.; Andreoiu, C.; Ball, G. C.; Ballast, T.; Bartlett, C.; Bender, P. C.; Bernier, N.; Bianco, L.; Bishop, D.; Brennan, D.; Bruhn, T.; Cheeseman, A.; Churchman, R.; Ciccone, S.; Davids, B.; Demand, G.; Dillmann, I.; Garnsworthy, A. B.; Garrett, P. E.; Georges, S.; Hackman, G.; Hadinia, B.; Kokke, R.; Krücken, R.; Linn, Y.; Lim, C.; Martin, J.-P.; Miller, D.; Mills, W. J.; Morrison, L. N.; Ohlmann, C. A.; Park, J.; Pearson, C. J.; Pore, J. L.; Rajabali, M. M.; Rand, E. T.; Rizwan, U.; Sarazin, F.; Shaw, B.; Starosta, K.; Svensson, C. E.; Sumithrarachchi, C.; Unsworth, C.; Voss, P.; Wang, Z. M.; Williams, J.; Wong, J.; Wong, S.

The GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) project is a major upgrade of the decay spectroscopy capabilities at TRIUMF-ISAC. GRIFFIN will replace the 8π spectrometer with an array of up to 16 large-volume HPGe clover detectors and use a state-of-the-art digital data acquisition system. The existing ancillary detector systems that had been developed for 8π, such as the SCEPTAR array for β-tagging, PACES for high-resolution internal conversion electron spectroscopy, and the DANTE array of LaBr3/BaF2 scintillators for fast γ-ray timing, will be used with GRIFFIN. GRIFFIN can also accommodate the new neutron detector array DESCANT (Deuterated Scintillator Array for Neutron Tagging), enabling the study of β-delayed neutron emitters. DESCANT consists of up to 70 detectors, each filled with approximately 2 liters of deuterated benzene, a liquid scintillator that provides pulse-shape discrimination (PSD) capabilities to distinguish between neutrons and γ-rays interacting with the detector. In addition, the anisotropic nature of n-d scattering as compared to the isotropic n-p scattering allows for the determination of the neutron energy spectrum directly from the pulse-height spectrum, complementing the time-of-flight (TOF) information. The installation of GRIFFIN is under way and first experiments are planned for the fall of 2014. The array will be completed in 2015 with the full complement of 16 clovers. DESCANT will be tested coupled with GRIFFIN in spring of 2015.

Testing Microshutter Arrays Using Commercial FPGA Hardware

NASA Technical Reports Server (NTRS)

Rapchun, David

2008-01-01

NASA is developing micro-shutter arrays for the Near Infrared Spectrometer (NIRSpec) instrument on the James Webb Space Telescope (JWST). These micro-shutter arrays allow NIRspec to do Multi Object Spectroscopy, a key part of the mission. Each array consists of 62414 individual 100 x 200 micron shutters. These shutters are magnetically opened and held electrostatically. Individual shutters are then programmatically closed using a simple row/column addressing technique. A common approach to provide these data/clock patterns is to use a Field Programmable Gate Array (FPGA). Such devices require complex VHSIC Hardware Description Language (VHDL) programming and custom electronic hardware. Due to JWST's rapid schedule on the development of the micro-shutters, rapid changes were required to the FPGA code to facilitate new approaches being discovered to optimize the array performance. Such rapid changes simply could not be made using conventional VHDL programming. Subsequently, National Instruments introduced an FPGA product that could be programmed through a Labview interface. Because Labview programming is considerably easier than VHDL programming, this method was adopted and brought success. The software/hardware allowed the rapid change the FPGA code and timely results of new micro-shutter array performance data. As a result, numerous labor hours and money to the project were conserved.

Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

NASA Technical Reports Server (NTRS)

1983-01-01

The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

Frequency domain and full waveform time domain inversion of ground based magnetometer, electrometer and incoherent scattering radar arrays to image strongly heterogenous 3-D Earth structure, ionospheric structure, and to predict the intensity of GICs in the power grid

NASA Astrophysics Data System (ADS)

Schultz, A.; Imamura, N.; Bonner, L. R., IV; Cosgrove, R. B.

2016-12-01

Ground-based magnetometer and electrometer arrays provide the means to probe the structure of the Earth's interior, the interactions of space weather with the ionosphere, and to anticipate the intensity of geomagnetically induced currents (GICs) in power grids. We present a local-to-continental scale view of a heterogeneous 3-D crust and mantle as determined from magnetotelluric (MT) observations across arrays of ground-based electric and magnetic field sensors. MT impedance tensors describe the relationship between electric and magnetic fields at a given site, thus implicitly they contain all known information on the 3-D electrical resistivity structure beneath and surrounding that site. By using multivariate transfer functions to project real-time magnetic observatory network data to areas surrounding electric power grids, and by projecting those magnetic fields through MT impedance tensors, the projected magnetic field can be transformed into predictions of electric fields along the path of the transmission lines, an essential element of predicting the intensity of GICs in the grid. Finally, we explore GICs, i.e. Earth-ionosphere coupling directly in the time-domain. We consider the fully coupled EM system, where we allow for a non-stationary ionospheric source field of arbitrary complexity above a 3-D Earth. We solve the simultaneous inverse problem for 3-D Earth conductivity and source field structure directly in the time domain. In the present work, we apply this method to magnetotelluric data obtained from a synchronously operating array of 25 MT stations that collected continuous MT waveform data in the interior of Alaska during the autumn and winter of 2015 under the footprint of the Poker Flat (Alaska) Incoherent Scattering Radar (PFISR). PFISR data yield functionals of the ionospheric electric field and ionospheric conductivity that constrain the MT source field. We show that in this region conventional robust MT processing methods struggle to produce reliable MT response functions at periods much greater than about 2,000 s, a consequence, we believe, of the complexity of the ionospheric source fields in this high latitude setting. This provides impetus for direct waveform inversion methods that dispense with typical parametric assumptions made about the MT source fields.

A Fast MoM Solver (GIFFT) for Large Arrays of Microstrip and Cavity-Backed Antennas

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

Fasenfest, B J; Capolino, F; Wilton, D

2005-02-02

A straightforward numerical analysis of large arrays of arbitrary contour (and possibly missing elements) requires large memory storage and long computation times. Several techniques are currently under development to reduce this cost. One such technique is the GIFFT (Green's function interpolation and FFT) method discussed here that belongs to the class of fast solvers for large structures. This method uses a modification of the standard AIM approach [1] that takes into account the reusability properties of matrices that arise from identical array elements. If the array consists of planar conducting bodies, the array elements are meshed using standard subdomain basismore » functions, such as the RWG basis. The Green's function is then projected onto a sparse regular grid of separable interpolating polynomials. This grid can then be used in a 2D or 3D FFT to accelerate the matrix-vector product used in an iterative solver [2]. The method has been proven to greatly reduce solve time by speeding up the matrix-vector product computation. The GIFFT approach also reduces fill time and memory requirements, since only the near element interactions need to be calculated exactly. The present work extends GIFFT to layered material Green's functions and multiregion interactions via slots in ground planes. In addition, a preconditioner is implemented to greatly reduce the number of iterations required for a solution. The general scheme of the GIFFT method is reported in [2]; this contribution is limited to presenting new results for array antennas made of slot-excited patches and cavity-backed patch antennas.« less

LSSA (Low-cost Silicon Solar Array) project

NASA Technical Reports Server (NTRS)

1976-01-01

Methods are explored for economically generating electrical power to meet future requirements. The Low-Cost Silicon Solar Array Project (LSSA) was established to reduce the price of solar arrays by improving manufacturing technology, adapting mass production techniques, and promoting user acceptance. The new manufacturing technology includes the consideration of new silicon refinement processes, silicon sheet growth techniques, encapsulants, and automated assembly production being developed under contract by industries and universities.

Preconditioned MoM Solutions for Complex Planar Arrays

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

Fasenfest, B J; Jackson, D; Champagne, N

2004-01-23

The numerical analysis of large arrays is a complex problem. There are several techniques currently under development in this area. One such technique is the FAIM (Faster Adaptive Integral Method). This method uses a modification of the standard AIM approach which takes into account the reusability properties of matrices that arise from identical array elements. If the array consists of planar conducting bodies, the array elements are meshed using standard subdomain basis functions, such as the RWG basis. These bases are then projected onto a regular grid of interpolating polynomials. This grid can then be used in a 2D ormore » 3D FFT to accelerate the matrix-vector product used in an iterative solver. The method has been proven to greatly reduce solve time by speeding the matrix-vector product computation. The FAIM approach also reduces fill time and memory requirements, since only the near element interactions need to be calculated exactly. The present work extends FAIM by modifying it to allow for layered material Green's Functions and dielectrics. In addition, a preconditioner is implemented to greatly reduce the number of iterations required for a solution. The general scheme of the FAIM method is reported in; this contribution is limited to presenting new results.« less

Low cost silicon solar cell array

NASA Technical Reports Server (NTRS)

Bartels, F. T. C.

1974-01-01

The technological options available for producing low cost silicon solar cell arrays were examined. A project value of approximately $250/sq m and $2/watt is projected, based on mass production capacity demand. Recommendations are included for the most promising cost reduction options.

Design of area array CCD image acquisition and display system based on FPGA

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Ning; Li, Tianting; Pan, Yue; Dai, Yuming

2014-09-01

With the development of science and technology, CCD(Charge-coupled Device) has been widely applied in various fields and plays an important role in the modern sensing system, therefore researching a real-time image acquisition and display plan based on CCD device has great significance. This paper introduces an image data acquisition and display system of area array CCD based on FPGA. Several key technical challenges and problems of the system have also been analyzed and followed solutions put forward .The FPGA works as the core processing unit in the system that controls the integral time sequence .The ICX285AL area array CCD image sensor produced by SONY Corporation has been used in the system. The FPGA works to complete the driver of the area array CCD, then analog front end (AFE) processes the signal of the CCD image, including amplification, filtering, noise elimination, CDS correlation double sampling, etc. AD9945 produced by ADI Corporation to convert analog signal to digital signal. Developed Camera Link high-speed data transmission circuit, and completed the PC-end software design of the image acquisition, and realized the real-time display of images. The result through practical testing indicates that the system in the image acquisition and control is stable and reliable, and the indicators meet the actual project requirements.

Performance, size, mass, and cost estimates for projected 1kW EOL Si, InP, and GaAs arrays

NASA Technical Reports Server (NTRS)

Slifer, Luther W., Jr.

1991-01-01

One method of evaluating the potential of emerging solar cell and array technologies is to compare their projected capabilities in space flight applications to those of established Si solar cells and arrays. Such an application-oriented comparison provides an integrated view of the elemental comparisons of efficiency, radiation resistance, temperature sensitivity, size, mass, and cost in combination. In addition, the assumptions necessary to make the comparisons provide insights helpful toward determining necessary areas of development or evaluation. Finally, as developments and evaluations progress, the results can be used in more precisely defining the overall potential of the new technologies in comparison to existing technologies. The projected capabilities of Si, InP, and GaAs cells and arrays are compared.

Problems in nonlinear acoustics: Scattering of sound by sound, parametric receiving arrays, nonlinear effects in asymmetric sound beams and pulsed finite amplitude sound beams

NASA Astrophysics Data System (ADS)

Hamilton, Mark F.

1989-08-01

Four projects are discussed in this annual summary report, all of which involve basic research in nonlinear acoustics: Scattering of Sound by Sound, a theoretical study of two nonconlinear Gaussian beams which interact to produce sum and difference frequency sound; Parametric Receiving Arrays, a theoretical study of parametric reception in a reverberant environment; Nonlinear Effects in Asymmetric Sound Beams, a numerical study of two dimensional finite amplitude sound fields; and Pulsed Finite Amplitude Sound Beams, a numerical time domain solution of the KZK equation.

Photovoltaic applications of Compound Parabolic Concentrator (CPC)

NASA Technical Reports Server (NTRS)

Winston, R.

1975-01-01

The use of a compound parabolic concentrator as field collector, in conjunction with a primary focusing concentrator for photovoltaic applications is studied. The primary focusing concentrator can be a parabolic reflector, an array of Fresnel mirrors, a Fresnel lens or some other lens. Silicon solar cell grid structures are proposed that increase efficiency with concentration up to 10 suns. A ray tracing program has been developed to determine energy distribution at the exit of a compound parabolic concentrator. Projected total cost of a CPC/solar cell system will be between 4 and 5 times lower than for flat plate silicon cell arrays.

A ring lasers array for fundamental physics

NASA Astrophysics Data System (ADS)

Di Virgilio, Angela; Allegrini, Maria; Beghi, Alessandro; Belfi, Jacopo; Beverini, Nicolò; Bosi, Filippo; Bouhadef, Bachir; Calamai, Massimo; Carelli, Giorgio; Cuccato, Davide; Maccioni, Enrico; Ortolan, Antonello; Passeggio, Giuseppe; Porzio, Alberto; Ruggiero, Matteo Luca; Santagata, Rosa; Tartaglia, Angelo

2014-12-01

After reviewing the importance of light as a probe for testing the structure of space-time, we describe the GINGER project. GINGER will be a three-dimensional array of large-size ring-lasers able to measure the de Sitter and Lense-Thirring effects. The instrument will be located at the underground laboratory of Gran Sasso, in Italy. We describe the preliminary actions and measurements already under way and present the full road map to GINGER. The intermediate apparatuses GP2 and GINGERino are described. GINGER is expected to be fully operating in few years. xml:lang="fr"

Final Report, “Exploiting Global View for Resilience”

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

Chien, Andrew

2017-03-29

Final technical report for the "Exploiting Global View for Resilience" project. The GVR project aims to create a new approach to portable, resilient applications. The GVR approach builds on a global view data model,, adding versioning (multi-version), user control of timing and rate (multi-stream), and flexible cross layer error signalling and recovery. With a versioned array as a portable abstraction, GVR enables application programmers to exploit deep scientific and application code insights to manage resilience (and its overhead) in a flexible, portable fashion.

Automated Array Assembly, Phase 2. Low-cost Solar Array Project, Task 4

NASA Technical Reports Server (NTRS)

Lopez, M.

1978-01-01

Work was done to verify the technological readiness of a select process sequence with respect to satisfying the Low Cost Solar Array Project objectives of meeting the designated goals of $.50 per peak watt in 1986 (1975 dollars). The sequence examined consisted of: (1) 3 inches diameter as-sawn Czochralski grown 1:0:0 silicon, (2) texture etching, (3) ion implanting, (4) laser annealing, (5) screen printing of ohmic contacts and (6) sprayed anti-reflective coatings. High volume production projections were made on the selected process sequence. Automated processing and movement of hardware at high rates were conceptualized to satisfy the PROJECT's 500 MW/yr capability. A production plan was formulated with flow diagrams integrating the various processes in the cell fabrication sequence.

Illuminating the Intricate Details of Tremor and Slow Slip Using an Array of Arrays

NASA Astrophysics Data System (ADS)

Creager, K. C.; Vidale, J. E.; Sweet, J. R.; Chestler, S.; Ghosh, A.

2014-12-01

Our Array of Arrays experiment consisted of eight 1-km aperture arrays, each containing 10-20 three-component continuously recording stations. One of these arrays ran continuously for five years and the others for more than one year. We applied frequency-domain beam forming to each array, and a multi-beam back projection method to detect and locate tremor on the Cascadia subduction plate interface every minute. We have also used the arrays to detect and locate over 10,000 tiny repeating Low-Frequency Earthquakes (LFEs) in dozens of distinct families. Repeating events are detected by autocorrelating every 6-s window with every other one during many 1-hour periods and stacking them across several stations to find repeating events. Clean templates are built for each family by iteratively scanning for new repeats and stacking them into the previous template. LFE catalogs are obtained by scanning templates through years of continuous data. Waveform similarities across LFEs and across stations within arrays are used to estimate seismic moment, double-difference event locations and source spectra. These methods have revealed fascinating space-time patterns in both tremor and LFEs that shed light on the propagation modes of slow slip earthquakes on the subduction plate interface including tremor streaks that propagate 100 km/hour parallel to relative plate motion, Rapid Tremor Reversals that propagate at 10 km/hour, and up to 4 times variations in the 0.4 km/hour along-strike propagation speed of the main rupture front that indicates sticky spots on the plate interface. Rather than following a standard Gutenberg-Richter power-law relation, the distributions of seismic moment of LFEs within each family follow an exponential law, allowing estimates of characteristic size. LFEs for a given family cluster in time. Going up dip, time between LFE bursts vary systematically from about a week to a year, durations from an hour to several days, and characteristic moment magnitudes from 1.25 to 1.85. The characteristic moment for up dip LFEs is thus 8 times bigger than their down-dip counter parts. Double-difference locations indicate that many of the families occur on patches that are elongated in the direction of relative plate motion, perhaps related to structural features on the plate interface.

Design for Review - Applying Lessons Learned to Improve the FPGA Review Process

NASA Technical Reports Server (NTRS)

Figueiredo, Marco A.; Li, Kenneth E.

2014-01-01

Flight Field Programmable Gate Array (FPGA) designs are required to be independently reviewed. This paper provides recommendations to Flight FPGA designers to properly prepare their designs for review in order to facilitate the review process, and reduce the impact of the review time in the overall project schedule.

Range and egomotion estimation from compound photodetector arrays with parallel optical axis using optical flow techniques.

PubMed

Chahl, J S

2014-01-20

This paper describes an application for arrays of narrow-field-of-view sensors with parallel optical axes. These devices exhibit some complementary characteristics with respect to conventional perspective projection or angular projection imaging devices. Conventional imaging devices measure rotational egomotion directly by measuring the angular velocity of the projected image. Translational egomotion cannot be measured directly by these devices because the induced image motion depends on the unknown range of the viewed object. On the other hand, a known translational motion generates image velocities which can be used to recover the ranges of objects and hence the three-dimensional (3D) structure of the environment. A new method is presented for computing egomotion and range using the properties of linear arrays of independent narrow-field-of-view optical sensors. An approximate parallel projection can be used to measure translational egomotion in terms of the velocity of the image. On the other hand, a known rotational motion of the paraxial sensor array generates image velocities, which can be used to recover the 3D structure of the environment. Results of tests of an experimental array confirm these properties.

Advanced Laboratory and Field Arrays (ALFA) OWC Phase 1 Test

DOE Data Explorer

Bret Bosma

2016-11-07

Data from Phase 1 testing of a single ALFA OWC device at the O.H. Hinsdale Wave Research Laboratory (HWRL) at Oregon State University in Fall of 2016. Contains two zip files of raw data, one of project data ("array"), and a diagram of the device with dimensions. A "readme" file in the project data archive under "Docs" helps to explains the project data.

Advanced photovoltaic solar array - Design and performance

NASA Technical Reports Server (NTRS)

Kurland, Richard; Stella, Paul

1992-01-01

This paper reports on the development of an ultralightweight flexible blanket, flatpack, foldout solar array design that can provide 3- to 4-fold improvement on specific power performance of current rigid panel arrays and a factor of two improvement over a first-generation flexible blanket array developed as a forerunner to the Space Station Freedom array. To date a prototype wing has been built with a projected specific power performance of about 138 W/kg at beginning-of-life (BOL) and 93 W/kg end-of-life (EOL) at 12 kW (BOL) for a 10-year geosynchronous (GEO) mission. The prototype wing hardware has been subjected to a series of system-level tests to demonstrate design feasibility. The design of the array is summarized. The major trade studies that led to the selection of the baseline design are discussed. Key system-level and component-level testing are described. Array-level performance projections are presented as a function of existing and advanced solar array component technology for various mission applications.

The NASA Deep Space Network (DSN) Array

NASA Technical Reports Server (NTRS)

Gatti, Mark

2006-01-01

The DSN Array Project is currently working with Senior Management at both JPL and NASA to develop strategies towards starting a major implementation project. Several studies within NASA are concluding, all of which recommend that any future DSN capability include arraying of antennas to increase performance. Support of Deep Space, Lunar, and CEV (crewed exploration vehicle) missions is possible. High data rate and TDRSS formatting is being investigated. Any future DSN capacity must include Uplink. Current studies ongoing to investigate and develop technologies for uplink arraying; provides advantages in three ways: 1) N2 effect. EIRP grows as N2(-vs-N for a downlink array); 2) Improved architectural options (can separate uplink and downlink); and 3) Potential for more cost effective transmitters for fixed EIRP.

The ASTRI SST-2M telescope prototype for the Cherenkov Telescope Array: camera DAQ software architecture

NASA Astrophysics Data System (ADS)

Conforti, Vito; Trifoglio, Massimo; Bulgarelli, Andrea; Gianotti, Fulvio; Fioretti, Valentina; Tacchini, Alessandro; Zoli, Andrea; Malaguti, Giuseppe; Capalbi, Milvia; Catalano, Osvaldo

2014-07-01

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project financed by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. Within this framework, INAF is currently developing an end-to-end prototype of a Small Size dual-mirror Telescope. In a second phase the ASTRI project foresees the installation of the first elements of the array at CTA southern site, a mini-array of 7 telescopes. The ASTRI Camera DAQ Software is aimed at the Camera data acquisition, storage and display during Camera development as well as during commissioning and operations on the ASTRI SST-2M telescope prototype that will operate at the INAF observing station located at Serra La Nave on the Mount Etna (Sicily). The Camera DAQ configuration and operations will be sequenced either through local operator commands or through remote commands received from the Instrument Controller System that commands and controls the Camera. The Camera DAQ software will acquire data packets through a direct one-way socket connection with the Camera Back End Electronics. In near real time, the data will be stored in both raw and FITS format. The DAQ Quick Look component will allow the operator to display in near real time the Camera data packets. We are developing the DAQ software adopting the iterative and incremental model in order to maximize the software reuse and to implement a system which is easily adaptable to changes. This contribution presents the Camera DAQ Software architecture with particular emphasis on its potential reuse for the ASTRI/CTA mini-array.

MEMS-based flexible reflective analog modulators (FRAM) for projection displays: a technology review and scale-down study

NASA Astrophysics Data System (ADS)

Picard, Francis; Ilias, Samir; Asselin, Daniel; Boucher, Marc-André; Duchesne, François; Jacob, Michel; Larouche, Carl; Vachon, Carl; Niall, Keith K.; Jerominek, Hubert

2011-02-01

A MEMS based technology for projection display is reviewed. This technology relies on mechanically flexible and reflective microbridges made of aluminum alloy. A linear array of such micromirrors is combined with illumination and Schlieren optics to produce a pixels line. Each microbridge in the array is individually controlled using electrostatic actuation to adjust the pixels intensities. Results of the simulation, fabrication and characterization of these microdevices are presented. Activation voltages below 250 V with response times below 10 μs were obtained for 25 μm × 25 μm micromirrors. With appropriate actuation voltage waveforms, response times of 5 μs and less are achievable. A damage threshold of the mirrors above 8 kW/cm2 has been evaluated. Development of the technology has produced projector engines demonstrating this light modulation principle. The most recent of these engines is DVI compatible and displays VGA video streams at 60 Hz. Recently applications have emerged that impose more stringent requirements on the dimensions of the MEMS array and associated optical system. This triggered a scale down study to evaluate the minimum micromirror size achievable, the impact of this reduced size on the damage threshold and the achievable minimum size of the associated optical system. Preliminary results of this scale down study are reported. FRAM with active surface as small as 5 μm × 5 μm have been investigated. Simulations have shown that such micromirrors could be activated with 107 V to achieve f-number of 1.25. The damage threshold has been estimated for various FRAM sizes. Finally, design of a conceptual miniaturized projector based on 1000×1 array of 5 μm × 5 μm micromirrors is presented. The volume of this projector concept is about 12 cm3.

Point-Focus Concentration Compact Telescoping Array: Extreme Environments Solar Power Base Phase Final Report

NASA Technical Reports Server (NTRS)

McEachen, Michael E.; Murphy, Dave; Meinhold, Shen; Spink, Jim; Eskenazi, Mike; O'Neill, Mark

2017-01-01

Orbital ATK, in partnership with Mark ONeill LLC (MOLLC), has developed a novel solar array platform, PFC-CTA, which provides a significant advance in performance and cost reduction compared to all currently available space solar systems. PFC refers to the Point Focus Concentration of light provided by MOLLCs thin, flat Fresnel optics. These lenses focus light to a point of approximately 100 times the intensity of the ambient light, onto a solar cell of approximately 125th the size of the lens. CTA stands for Compact Telescoping Array, which is the solar array blanket structural platform originally devised by NASA and currently being advanced by Orbital ATK and partners under NASA and AFRL funding to a projected TRL 5+ by late-2018.The NASA Game Changing Development Extreme Environment Solar Power (EESP) Base Phase study has enabled Orbital ATK to refine component designs, perform component level and system performance analyses, and test prototype hardware of the key elements of PFC-CTA, and increased the TRL of PFC-specific technology elements to TRL 4. Key performance metrics currently projected are as follows: Scalability from 5 kW to 300 kW per wing (AM0); Specific Power 500 Wkg (AM0); Stowage Efficiency 100 kWm3; 5:1 margin on pointing tolerance vs. capability; 50 launched cost savings; Wide range of operability between Venus and Saturn by active andor passive thermal management.

High-resolution laser-projection display system using a grating electromechanical system (GEMS)

NASA Astrophysics Data System (ADS)

Brazas, John C.; Kowarz, Marek W.

2004-01-01

Eastman Kodak Company has developed a diffractive-MEMS spatial-light modulator for use in printing and display applications, the grating electromechanical system (GEMS). This modulator contains a linear array of pixels capable of high-speed digital operation, high optical contrast, and good efficiency. The device operation is based on deflection of electromechanical ribbons suspended above a silicon substrate by a series of intermediate supports. When electrostatically actuated, the ribbons conform to the supporting substructure to produce a surface-relief phase grating over a wide active region. The device is designed to be binary, switching between a reflective mirror state having suspended ribbons and a diffractive grating state having ribbons in contact with substrate features. Switching times of less than 50 nanoseconds with sub-nanosecond jitter are made possible by reliable contact-mode operation. The GEMS device can be used as a high-speed digital-optical modulator for a laser-projection display system by collecting the diffracted orders and taking advantage of the low jitter. A color channel is created using a linear array of individually addressable GEMS pixels. A two-dimensional image is produced by sweeping the line image of the array, created by the projection optics, across the display screen. Gray levels in the image are formed using pulse-width modulation (PWM). A high-resolution projection display was developed using three 1080-pixel devices illuminated by red, green, and blue laser-color primaries. The result is an HDTV-format display capable of producing stunning still and motion images with very wide color gamut.

Expanded Owens Valley Solar Array Science and Data Products

NASA Astrophysics Data System (ADS)

Gary, Dale E.; Hurford, G. J.; Nita, G. M.; Fleishman, G. D.; McTiernan, J. M.

2010-05-01

The Owens Valley Solar Array (OVSA) has been funded for major expansion, to create a university-based facility serving a broad scientific community, to keep the U.S. competitive in the field of solar radio physics. The project, funded by the National Science Foundation through the MRI-Recovery and Reinvestment program, will result in a world-class facility for scientific research at microwave radio frequencies (1-18 GHz) in solar and space weather physics. The project also includes an exciting program of targeted astronomical science. The solar science to be addressed focuses on the magnetic structure of the solar corona, on transient phenomena resulting from magnetic interactions, including the sudden release of energy and subsequent particle acceleration and heating, and on space weather phenomena. The project will support the scientific community by providing open data access and software tools for analysis of the data, to exploit synergies with on-going solar research in other wavelength bands. The New Jersey Institute of Technology (NJIT) will upgrade OVSA from its current complement of 7 antennas to a total of 15 by adding 8 new antennas, and will reinvest in the existing infrastructure by replacing the existing control systems, signal transmission, and signal processing with modern, far more capable and reliable systems based on new technology developed for the Frequency Agile Solar Radiotelescope (FASR). The project will be completed in time to provide solar-dedicated observations during the upcoming solar maximum in 2013 and beyond. We will detail the new science addressed by the expanded array, and provide an overview of the expected data products.

Digital Mapping of Buried Pipelines with a Dual Array System

DOT National Transportation Integrated Search

2005-03-01

The project carried out under this agreement, which was informally called the "Dual Array Project" (the term we will use in this report), was part of the research efforts at the Office of Pipeline Safety at U.S. DOT, and was one of seven contracts aw...

Proceedings of the Flat-Plate Solar Array Project Research Forum on Photovoltaic Metallization Systems

NASA Technical Reports Server (NTRS)

1983-01-01

A photovoltaic Metallization Research forum, under the sponsorship of the Flat-Plate Solar Array Project consisted of five sessions, covering: (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques, and (5) future metallization challenges.

Imaging 2015 Mw 7.8 Gorkha Earthquake and Its Aftershock Sequence Combining Multiple Calibrated Global Seismic Arrays

NASA Astrophysics Data System (ADS)

LI, B.; Ghosh, A.

2016-12-01

The 2015 Mw 7.8 Gorkha earthquake provides a good opportunity to study the tectonics and earthquake hazards in the Himalayas, one of the most seismically active plate boundaries. Details of the seismicity patterns and associated structures in the Himalayas are poorly understood mainly due to limited instrumentation. Here, we apply a back-projection method to study the mainshock rupture and the following aftershock sequence using four large aperture global seismic arrays. All the arrays show eastward rupture propagation of about 130 km and reveal similar evolution of seismic energy radiation, with strong high-frequency energy burst about 50 km north of Kathmandu. Each single array, however, is typically limited by large azimuthal gap, low resolution, and artifacts due to unmodeled velocity structures. Therefore, we use a self-consistent empirical calibration method to combine four different arrays to image the Gorkha event. It greatly improves the resolution, can better track rupture and reveal details that cannot be resolved by any individual array. In addition, we also use the same arrays at teleseismic distances and apply a back-projection technique to detect and locate the aftershocks immediately following the Gorkha earthquake. We detect about 2.5 times the aftershocks recorded by the Advance National Seismic System comprehensive earthquake catalog during the 19 days following the mainshock. The aftershocks detected by the arrays show an east-west trend in general, with majority of the aftershocks located at the eastern part of the rupture patch and surrounding the rupture zone of the largest Mw 7.3 aftershock. Overall spatiotemporal aftershock pattern agrees well with global catalog, with our catalog showing more details relative to the standard global catalog. The improved aftershock catalog enables us to better study the aftershock dynamics, stress evolution in this region. Moreover, rapid and better imaging of aftershock distribution may aid rapid response and hazard assessment after destructive large earthquakes. Existing multiple global seismic arrays, when properly calibrated and used in combinations, provide a high resolution image of rupture of large earthquakes and spatiotemporal distribution of aftershocks.

Proceedings of the 16th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1980-01-01

The principal achievement of the Low Cost Solar Array Project in 1980 was the attainment of $2.80/Wp Technical Readiness, and that processes and equipment now commercially available can make possible a deliverable product in 1982. A prototype array for intermediate load applications was demonstrated using frameless modules. It was proof tested to 40 lb/sq ft loading, and priced at $24/sq m, including array fabrication, module installation, shipping to the site and site installation for quantities of 20 MW.

Embedded Electro-Optic Sensor Network for the On-Site Calibration and Real-Time Performance Monitoring of Large-Scale Phased Arrays

DTIC Science & Technology

2005-07-09

This final report summarizes the progress during the Phase I SBIR project entitled Embedded Electro - Optic Sensor Network for the On-Site Calibration...network based on an electro - optic field-detection technique (the Electro - optic Sensor Network, or ESN) for the performance evaluation of phased

Advanced Photovoltaic Solar Array program status

NASA Technical Reports Server (NTRS)

Kurland, Richard M.; Stella, Paul M.

1989-01-01

The Advanced Photolvoltaic Solar Array (APSA) Program is discussed. The objective of the program is to demonstrate a producible array system by the end of this decade with a beginning-of-life (BOL) specific power of 130 W/kg at 10 kW as an intermediate milestone toward the ultimate goal of 300 W/kg at 25 kW by the year 2000. The near-term goal represents a significant improvement over existing rigid panel flight arrays (25 to 45 W/kg) and the first-generation flexible blanket NASA/OAST SAFE I array of the early 1980s, which was projected to provide about 60 W/kg BOL. The prototype wing hardware is in the last stages of fabrication and integration. The current status of the program is reported. The array configuration and key design details are shown. Projections are shown for future performance enhancements that may be expected through the use of advanced structural components and solar cells.

Calibrating the MicroBooNE Photomultiplier Tube (PMT) Array with Michel Electrons from Cosmic Ray Muons

NASA Astrophysics Data System (ADS)

Greene, Amy

2013-04-01

MicroBooNE is a neutrino experiment at Fermilab designed to investigate the 3σ low-energy electron candidate events measured by the MiniBooNE experiment. Neutrinos from the Booster Neutrino Beam are detected by a 89-ton liquid argon time projection chamber, which is expected to start taking data in 2014. MicroBooNE measures both the ionization electrons and scintillation light produced by neutrino interactions in the liquid argon. The scintillation light is collected by an array of 30 PMTs located at one side of the detector. This array can be calibrated using Michel electrons from stopping cosmic ray muons, by fitting the measured PMT response with the theoretical expectation. I will report on the progress of the PMT calibration software that has been developed using the MicroBooNE Monte Carlo.

Cryogenic Design of the Setup for MARE-1 in Milan

NASA Astrophysics Data System (ADS)

Schaeffer, D.; Arnaboldi, C.; Ceruti, G.; Ferri, E.; Kilbourne, C.; Kraft-Bermuth, S.; Margesin, B.; McCammon, D.; Monfardini, A.; Nucciotti, A.; Pessina, G.; Previtali, E.; Sisti, M.

2008-05-01

A large worldwide collaboration is growing around the project of Micro-calorimeter Arrays for a Rhenium Experiment (MARE) for a direct calorimetric measurement of the neutrino mass. To validate the use of cryogenic detectors by checking the presence of unexpected systematic errors, two first experiments are planned using the available techniques composed of arrays of 300 detectors to measure 1010 events in a reasonable time of 3 years (step MARE-1) to reach a sensitivity on the neutrino mass of ˜2 eV/c2. Our experiment in Milan is based on compensated doped silicon implanted thermistor arrays made in NASA/GSFC and on AgReO4 crystals. We present here the design of the cryogenic system that integrates all the requirements for such experiment (electronics for high impedances, low parasitic capacitances, low micro-phonic noise).

Camp Blanding Lightning Mapping Array

NASA Technical Reports Server (NTRS)

Blakeslee,Richard; Christian, Hugh; Bailey, Jeffrey; Hall, John; Uman, Martin; Jordan, Doug; Krehbiel, Paul; Rison, William; Edens, Harald

2011-01-01

A seven station, short base-line Lightning Mapping Array was installed at the Camp Blanding International Center for Lightning Research and Testing (ICLRT) during April 2011. This network will support science investigations of Terrestrial Gamma-Ray Flashes (TGFs) and lightning initiation using rocket triggered lightning at the ICLRT. The network operations and data processing will be carried out through a close collaboration between several organizations, including the NASA Marshall Space Flight Center, University of Alabama in Huntsville, University of Florida, and New Mexico Tech. The deployment was sponsored by the Defense Advanced Research Projects Agency (DARPA). The network does not have real-time data dissemination. Description, status and plans will be discussed.

Noninvasive photoacoustic detecting intraocular foreign bodies with an annular transducer array.

PubMed

Yang, Diwu; Zeng, Lvming; Pan, Changning; Zhao, Xuehui; Ji, Xuanrong

2013-01-14

We present a fast photoacoustic imaging system based on an annular transducer array for detection of intraocular foreign bodies. An eight-channel data acquisition system is applied to capture the photoacoustic signals using multiplexing and the total time of data acquisition and transferring is within 3 s. A limited-view filtered back projection algorithm is used to reconstruct the photoacoustic images. Experimental models of intraocular metal and glass foreign bodies were constructed on ex vivo pig's eyes and clear photoacoustic images of intraocular foreign bodies were obtained. Experimental results demonstrate the photoacoustic imaging system holds the potential for in clinic detecting the intraocular foreign bodies.

Development of High-Fill-Factor Large-Aperture Micromirrors for Agile Optical Phased Arrays

DTIC Science & Technology

2010-02-28

Final Project Report Contract/Grant Title: Development of High-Fill-Factor Large-Aperture Micromirrors for Agile Optical Phased Arrays...factor (HFF) micromirror array (MMA) has been proposed, fabricated and tested. Optical-phased-array (OPA) beam steering based on the HFF MMA has also...electrically tuned to multiple 2. 1. Background High-fill-factor (HFF) micromirror arrays (MMAs) can form optical phased arrays (OPAs) for laser beam

Summary of flat-plate solar array project documentation: Abstracts of published documents, 1975-1986, revision 1

NASA Technical Reports Server (NTRS)

Phillips, M. J.

1986-01-01

Abstracts of final reports, or the latest quarterly or annual, of the Flat-Plate Solar Array (FSA) Project Contractor of Jet Propulsion Laboratory (JPL) in-house activities are presented. Also presented is a list of proceedings and publications, by author, of work connected with the project. The aim of the program has been to stimulate the development of technology that will enable the private sector to manufacture and widely use photovoltaic systems for the generation of electricity in residential, commercial, industrial, and Government applications at a cost per watt that is competitive with utility generated power. FSA Project activities have included the sponsoring of research and development efforts in silicon refinement processes, advanced silicon sheet growth techniques, higher efficiency solar cells, solar cell/module fabrication processes, encapsulation, module/array engineering and reliability, and economic analyses.

Flat-plate solar array progress and plans

NASA Technical Reports Server (NTRS)

Callaghan, W. T.

1984-01-01

The results of research into the technology of flat-plate solar arrays undertaken in the Flat-Plate Solar Array Project under the sponsorship of the U.S. Department of Energy are surveyed. Topics examined include Si refinement, ribbon-sheet substrate formation, module process sequences, environmental isolation, module engineering and testing, and photovoltaic-array economics.

Solar Arrays for Low-Irradiance Low-Temperature and High-Radiation Environments

NASA Technical Reports Server (NTRS)

Boca, Andreea (Principal Investigator); Stella, Paul; Kerestes, Christopher; Sharps, Paul

2017-01-01

This is the Base Period final report DRAFT for the JPL task 'Solar Arrays for Low-Irradiance Low-Temperature and High-Radiation Environments', under Task Plan 77-16518 TA # 21, for NASA's Extreme Environments Solar Power (EESP) project. This report covers the Base period of performance, 7/18/2016 through 5/2/2017.The goal of this project is to develop an ultra-high efficiency lightweight scalable solar array technology for low irradiance, low temperature and high-radiation (LILT/Rad) environments. The benefit this technology will bring to flight systems is a greater than 20 reduction in solar array surface area, and a six-fold reduction in solar array mass and volume. The EESP project objectives are summarized in the 'NRA Goal' column of Table 1. Throughout this report, low irradiance low temperature (LILT) refers to 5AU -125 C test conditions; beginning of life (BOL) refers to the cell state prior to radiation exposure; and end of life (EOL) refers to the test article condition after exposure to a radiation dose of 4e15 1MeV e(-)/cm(exp 2).

Imaging System With Confocally Self-Detecting Laser.

DOEpatents

Webb, Robert H.; Rogomentich, Fran J.

1996-10-08

The invention relates to a confocal laser imaging system and method. The system includes a laser source, a beam splitter, focusing elements, and a photosensitive detector. The laser source projects a laser beam along a first optical path at an object to be imaged, and modulates the intensity of the projected laser beam in response to light reflected from the object. A beam splitter directs a portion of the projected laser beam onto a photodetector. The photodetector monitors the intensity of laser output. The laser source can be an electrically scannable array, with a lens or objective assembly for focusing light generated by the array onto the object of interest. As the array is energized, its laser beams scan over the object, and light reflected at each point is returned by the lens to the element of the array from which it originated. A single photosensitive detector element can generate an intensity-representative signal for all lasers of the array. The intensity-representative signal from the photosensitive detector can be processed to provide an image of the object of interest.

Alphabus Solar Array- Versatile and Powerful Solar Arrays for Tomorrow's Commercial Telecom Satellites

NASA Astrophysics Data System (ADS)

Pfefferkorn, T.; Oxynos, C.; Greff, P.; Gerlach, L.

2008-09-01

After the successful series of Eurostar 3000 and Spacebus 4000 satellites and due to the demand of satellite operators for even larger and more powerful satellites, ESA decided to co-fund the development of a new satellite platform which covers the market segment beyond the upper limits of both satellite families.The new satellite bus family Alphabus is developed in the frame of ARTES 8 project by a joint project team of ASTRIUM and TAS, whereas the solar array is developed by ASTRIUM GmbH.The main approaches in this design phase for the Alphabus solar array were to find a standardized and scaleable design to production and to use qualification heritage from former projects, especially Eurostar 3000, as far as possible. The main challenges for the solar array design and test philosophy were the usage of lateral deployment and related sequential deployment and the bus voltage of 102,5V and related ESD precautions.This paper provides an overview of the different configurations, their main design features and performance parameters. In addition it summarizes the development and verification approach and shows the actual qualification status.

Optical Demonstration of a Medical Imaging System with an EMCCD-Sensor Array for Use in a High Resolution Dynamic X-ray Imager

PubMed Central

Qu, Bin; Huang, Ying; Wang, Weiyuan; Sharma, Prateek; Kuhls-Gilcrist, Andrew T.; Cartwright, Alexander N.; Titus, Albert H.; Bednarek, Daniel R.; Rudin, Stephen

2011-01-01

Use of an extensible array of Electron Multiplying CCDs (EMCCDs) in medical x-ray imager applications was demonstrated for the first time. The large variable electronic-gain (up to 2000) and small pixel size of EMCCDs provide effective suppression of readout noise compared to signal, as well as high resolution, enabling the development of an x-ray detector with far superior performance compared to conventional x-ray image intensifiers and flat panel detectors. We are developing arrays of EMCCDs to overcome their limited field of view (FOV). In this work we report on an array of two EMCCD sensors running simultaneously at a high frame rate and optically focused on a mammogram film showing calcified ducts. The work was conducted on an optical table with a pulsed LED bar used to provide a uniform diffuse light onto the film to simulate x-ray projection images. The system can be selected to run at up to 17.5 frames per second or even higher frame rate with binning. Integration time for the sensors can be adjusted from 1 ms to 1000 ms. Twelve-bit correlated double sampling AD converters were used to digitize the images, which were acquired by a National Instruments dual-channel Camera Link PC board in real time. A user-friendly interface was programmed using LabVIEW to save and display 2K × 1K pixel matrix digital images. The demonstration tiles a 2 × 1 array to acquire increased-FOV stationary images taken at different gains and fluoroscopic-like videos recorded by scanning the mammogram simultaneously with both sensors. The results show high resolution and high dynamic range images stitched together with minimal adjustments needed. The EMCCD array design allows for expansion to an M×N array for arbitrarily larger FOV, yet with high resolution and large dynamic range maintained. PMID:23505330

Travel-time tomography in shallow water: experimental demonstration at an ultrasonic scale.

PubMed

Roux, Philippe; Iturbe, Ion; Nicolas, Barbara; Virieux, Jean; Mars, Jérôme I

2011-09-01

Acoustic tomography in a shallow ultrasonic waveguide is demonstrated at the laboratory scale between two source-receiver arrays. At a 1/1,000 scale, the waveguide represents a 1.1-km-long, 52-m-deep ocean acoustic channel in the kilohertz frequency range. Two coplanar arrays record the transfer matrix in the time domain of the waveguide between each pair of source-receiver transducers. A time-domain, double-beamforming algorithm is simultaneously performed on the source and receiver arrays that projects the multi-reflected acoustic echoes into an equivalent set of eigenrays, which are characterized by their travel times and their launch and arrival angles. Travel-time differences are measured for each eigenray every 0.1 s when a thermal plume is generated at a given location in the waveguide. Travel-time tomography inversion is then performed using two forward models based either on ray theory or on the diffraction-based sensitivity kernel. The spatially resolved range and depth inversion data confirm the feasibility of acoustic tomography in shallow water. Comparisons are made between inversion results at 1 and 3 MHz with the inversion procedure using ray theory or the finite-frequency approach. The influence of surface fluctuations at the air-water interface is shown and discussed in the framework of shallow-water ocean tomography. © 2011 Acoustical Society of America

A combined joint diagonalization-MUSIC algorithm for subsurface targets localization

NASA Astrophysics Data System (ADS)

Wang, Yinlin; Sigman, John B.; Barrowes, Benjamin E.; O'Neill, Kevin; Shubitidze, Fridon

2014-06-01

This paper presents a combined joint diagonalization (JD) and multiple signal classification (MUSIC) algorithm for estimating subsurface objects locations from electromagnetic induction (EMI) sensor data, without solving ill-posed inverse-scattering problems. JD is a numerical technique that finds the common eigenvectors that diagonalize a set of multistatic response (MSR) matrices measured by a time-domain EMI sensor. Eigenvalues from targets of interest (TOI) can be then distinguished automatically from noise-related eigenvalues. Filtering is also carried out in JD to improve the signal-to-noise ratio (SNR) of the data. The MUSIC algorithm utilizes the orthogonality between the signal and noise subspaces in the MSR matrix, which can be separated with information provided by JD. An array of theoreticallycalculated Green's functions are then projected onto the noise subspace, and the location of the target is estimated by the minimum of the projection owing to the orthogonality. This combined method is applied to data from the Time-Domain Electromagnetic Multisensor Towed Array Detection System (TEMTADS). Examples of TEMTADS test stand data and field data collected at Spencer Range, Tennessee are analyzed and presented. Results indicate that due to its noniterative mechanism, the method can be executed fast enough to provide real-time estimation of objects' locations in the field.

Imaging of Heterogeneous Structure beneath the Metropolitan Tokyo Area

NASA Astrophysics Data System (ADS)

Nakagawa, S.; Sakai, S.; Kurashimo, E.; Kato, A.; Hagiwara, H.; Kasahara, K.; Tanada, T.; Obara, K.; Hirata, N.

2009-12-01

Beneath the metropolitan Tokyo area, the Philippine Sea Plate (PSP) subducts and causes damaged mega-thrust earthquakes. The Dai-Dai-Toku Project revealed the geometry of the upper surface of PSP, and estimated a rupture process and a ground motion of the 1923 Kanto earthquake [Sato et al., 2005]. Hagiwara et al. (2006) estimated the velocity structure of Boso peninsula. However, these results are not sufficient for the assessment of the entire picture of the seismic hazards beneath the metropolitan Tokyo area including those due to an intra-slab M7+ earthquake. So, we have carried out a 5-year project since 2007, the Special Project for Earthquake Disaster Mitigation in the Metropolitan Tokyo area. Proving the more detailed geometry and physical properties (e.g. velocities, densities, attenuation) of PSP is very important to attain this issue. The core item of this project is the dense seismic array observation in metropolitan area, which is called the MeSO-net (Metropolitan Seismic Observation network). In order to obtain the high resolution images of a velocity structure, it is requested to construct a seismic network with a spacing of 2-5 km. The total number of seismic stations of the MeSO-net will be about 400 and will be deployed in 4 years. We deployed the 178 seismic stations, which construct 5 seismic arrays such as Tsukuba-Fujisawa (TF) array etc., by 2008, and we are now deploying the 45 seismic stations in this year. The MeSO-net data are quasi-real-time transferred to the data center at ERI [Kasahara et al., 2007; Nakagawa et al., 2007]. In this study, we applied the tomography to image the heterogeneous structure under the metropolitan Tokyo area. We selected events from the catalogue by Hagiwara et al. (2006) and merged the new event data observed by MeSO-net with these data. Around the Kanto region there are several seismic explorations using active sources were carried out [Sato et al., 2005; Oikawa et al., 2007]. Since these data may improve the velocity structure in shallower part, we added the arrival time data of these explorations into the dataset. Then, we applied the double-difference tomography method [Zhang and Thurber, 2003] to this dataset and estimated the fine-scale velocity structure. The initial velocity structure is the same in Hagiwara et al. (2006), and the VP/VS ratio is set to 1.73 for all grid nodes. The TF array passes directory above Tokyo and is parallel to Boso peninsula. The depth section of P-wave velocity structure along the TF array clearly shows that thin low-velocity layer which overlies high-velocity layer subducts towards northeast. This low-velocity layer corresponds to the oceanic crust of the subducting PSP. The increase of MeSO-net stations and event data may improve images of heterogeneous structure and contribute the purpose of this special project. Acknowledgement: This study was supported by the Earthquake Research Institute cooperative research program.

High resolution stationary digital breast tomosynthesis using distributed carbon nanotube x-ray source array.

PubMed

Qian, Xin; Tucker, Andrew; Gidcumb, Emily; Shan, Jing; Yang, Guang; Calderon-Colon, Xiomara; Sultana, Shabana; Lu, Jianping; Zhou, Otto; Spronk, Derrek; Sprenger, Frank; Zhang, Yiheng; Kennedy, Don; Farbizio, Tom; Jing, Zhenxue

2012-04-01

The purpose of this study is to investigate the feasibility of increasing the system spatial resolution and scanning speed of Hologic Selenia Dimensions digital breast tomosynthesis (DBT) scanner by replacing the rotating mammography x-ray tube with a specially designed carbon nanotube (CNT) x-ray source array, which generates all the projection images needed for tomosynthesis reconstruction by electronically activating individual x-ray sources without any mechanical motion. The stationary digital breast tomosynthesis (s-DBT) design aims to (i) increase the system spatial resolution by eliminating image blurring due to x-ray tube motion and (ii) reduce the scanning time. Low spatial resolution and long scanning time are the two main technical limitations of current DBT technology. A CNT x-ray source array was designed and evaluated against a set of targeted system performance parameters. Simulations were performed to determine the maximum anode heat load at the desired focal spot size and to design the electron focusing optics. Field emission current from CNT cathode was measured for an extended period of time to determine the stable life time of CNT cathode for an expected clinical operation scenario. The source array was manufactured, tested, and integrated with a Selenia scanner. An electronic control unit was developed to interface the source array with the detection system and to scan and regulate x-ray beams. The performance of the s-DBT system was evaluated using physical phantoms. The spatially distributed CNT x-ray source array comprised 31 individually addressable x-ray sources covering a 30 angular span with 1 pitch and an isotropic focal spot size of 0.6 mm at full width at half-maximum. Stable operation at 28 kV(peak) anode voltage and 38 mA tube current was demonstrated with extended lifetime and good source-to-source consistency. For the standard imaging protocol of 15 views over 14, 100 mAs dose, and 2 × 2 detector binning, the projection resolution along the scanning direction increased from 4.0 cycles/mm [at 10% modulation-transfer-function (MTF)] in DBT to 5.1 cycles/mm in s-DBT at magnification factor of 1.08. The improvement is more pronounced for faster scanning speeds, wider angular coverage, and smaller detector pixel sizes. The scanning speed depends on the detector, the number of views, and the imaging dose. With 240 ms detector readout time, the s-DBT system scanning time is 6.3 s for a 15-view, 100 mAs scan regardless of the angular coverage. The scanning speed can be reduced to less than 4 s when detectors become faster. Initial phantom studies showed good quality reconstructed images. A prototype s-DBT scanner has been developed and evaluated by retrofitting the Selenia rotating gantry DBT scanner with a spatially distributed CNT x-ray source array. Preliminary results show that it improves system spatial resolution substantially by eliminating image blur due to x-ray focal spot motion. The scanner speed of s-DBT system is independent of angular coverage and can be increased with faster detector without image degration. The accelerated lifetime measurement demonstrated the long term stability of CNT x-ray source array with typical clinical operation lifetime over 3 years.

Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

NASA Technical Reports Server (NTRS)

Zakrajsek, Robert J.

2000-01-01

The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate approximately five satellites on the orbital arc. Spread spectrum techniques will be employed to keep the power impinging on the adjacent satellites below their noise floor so that no interference results. This antenna is power limited. If the antenna elements (currently 254) are increased by a factor of 4 (1024) or 16 (4096), the gain will increase and the beamwidth will decrease in proportion. For the latter two antenna sizes, the power must be "backed off" to prevent interference with the neighboring satellites. The receiving antenna, which is approximately 90-cm high, 60-cm wide, and 3.5-cm thick, is composed of 1500 phased-array elements. The system phased-array controller can control both a 1500-element receiving antenna and a 500-element transmitting antenna. For ground testing, this controller will allow manual beam pointing and polarization alignment. For normal operation, the system can be connected to the receiving antenna and the navigation system for real-time autonomous track operation. This will be accomplished by first pointing both antennas at the satellite using information from the aircraft data bus. Then, the system phased-array controller will electronically adjust the antenna pointing of the receiving antenna to find the peak signal. After the peak signal has been found, the beam of the transmitting antenna will be pointed to the same steering angles as the receiving antenna. For initial ground testing without an aircraft, the ARINC 429 data bus (ARINC Inc., Annapolis, Maryland) will be simulated by a gyro system purchased for the follow-on to the Monolithic Microwave Integrated Circuit (MMIC) Arrays for Satellite Communication on the Move (MASCOM) Project. MASCOM utilized the Advanced Communications Technology Satellite (ACTS) with a pair of Ka-band experimental phased-array antennas.

A HWIL test facility of infrared imaging laser radar using direct signal injection

NASA Astrophysics Data System (ADS)

Wang, Qian; Lu, Wei; Wang, Chunhui; Wang, Qi

2005-01-01

Laser radar has been widely used these years and the hardware-in-the-loop (HWIL) testing of laser radar become important because of its low cost and high fidelity compare with On-the-Fly testing and whole digital simulation separately. Scene generation and projection two key technologies of hardware-in-the-loop testing of laser radar and is a complicated problem because the 3D images result from time delay. The scene generation process begins with the definition of the target geometry and reflectivity and range. The real-time 3D scene generation computer is a PC based hardware and the 3D target models were modeled using 3dsMAX. The scene generation software was written in C and OpenGL and is executed to extract the Z-buffer from the bit planes to main memory as range image. These pixels contain each target position x, y, z and its respective intensity and range value. Expensive optical injection technologies of scene projection such as LDP array, VCSEL array, DMD and associated scene generation is ongoing. But the optical scene projection is complicated and always unaffordable. In this paper a cheaper test facility was described that uses direct electronic injection to provide rang images for laser radar testing. The electronic delay and pulse shaping circuits inject the scenes directly into the seeker's signal processing unit.

Analysis of High Precision GPS Time Series and Strain Rates for the Geothermal Play Fairway Analysis of Washington State Prospects Project

DOE Data Explorer

Michael Swyer

2015-02-22

Global Positioning System (GPS) time series from the National Science Foundation (NSF) Earthscope’s Plate Boundary Observatory (PBO) and Central Washington University’s Pacific Northwest Geodetic Array (PANGA). GPS station velocities were used to infer strain rates using the ‘splines in tension’ method. Strain rates were derived separately for subduction zone locking at depth and block rotation near the surface within crustal block boundaries.

Head Mounted Display with a Roof Mirror Array Fold

NASA Technical Reports Server (NTRS)

Olczak, Eugene (Inventor)

2014-01-01

The present invention includes a head mounted display (HMD) worn by a user. The HMD includes a display projecting an image through an optical lens. The HMD also includes a one-dimensional retro reflective array receiving the image through the optical lens at a first angle with respect to the display and deflecting the image at a second angle different than the first angle with respect to the display. The one-dimensional retro reflective array reflects the image in order to project the image onto an eye of the user.

Improving time-lapse seismic repeatability: CO2CRC Otway site permanent geophone array field trials

NASA Astrophysics Data System (ADS)

Pevzner, Roman; Dupuis, Christian; Shulakova, Valeriya; Urosevic, Milovan; Lumley, David

2013-04-01

The proposed Stage 2C of the CO2CRC Otway project involves injection of a small amount (around 15,000 tonnes) of CO2/CH4 gas mixture into saline acquifer (Paaratte formation) at the depth of ~1.5 km. The seismic time-lapse signal will depend largely on the formation properties and the injection scenario, but is likely to be relatively weak. In order to improve time-lapse seismic monitoring capabilities by decreasing the noise level, a buried receiver arrays can be used. A small-scale trial of such an array was conducted at Otway site in June 2012. A set of 25 geophones was installed in 3 m deep boreholes in parallel to the same number of surface geophones. In addition, four geophones were placed into boreholes of 1 to 12 m depth. In order to assess the gain in the signal-to-noise ratio and repeatability, both active and passive seismic surveys were carried out. The surveys were conducted in relatively poor weather conditions, with rain, strong wind and thunderstorms increasing the noise level. We found that noise level for buried geophones is on average 20 dB lower compared to the surface ones. Furthermore, the combination of active and passive experiments has allowed us to perform a detailed classification of various noise sources. Acknowledgement The authors acknowledge the funding provided by the Australian government through its CRC program to support this CO2CRC research project. We also acknowledge the CO2CRC's corporate sponsors and the financial assistance provided through Australian National Low Emissions Coal Research and Development (ANLEC R&D). ANLEC R&D is supported by Australian Coal Association Low Emissions Technology Limited and the Australian Government through the Clean Energy Initiative.

Low-cost silicon solar array project environmental hail model for assessing risk to solar collectors

NASA Technical Reports Server (NTRS)

Gonzalez, C.

1977-01-01

The probability of solar arrays being struck by hailstones of various sizes as a function of geographic location and service life was assessed. The study complements parallel studies of solar array sensitivity to hail damage, the final objective being an estimate of the most cost effective level for solar array hail protection.

Controllable 3D Display System Based on Frontal Projection Lenticular Screen

NASA Astrophysics Data System (ADS)

Feng, Q.; Sang, X.; Yu, X.; Gao, X.; Wang, P.; Li, C.; Zhao, T.

2014-08-01

A novel auto-stereoscopic three-dimensional (3D) projection display system based on the frontal projection lenticular screen is demonstrated. It can provide high real 3D experiences and the freedom of interaction. In the demonstrated system, the content can be changed and the dense of viewing points can be freely adjusted according to the viewers' demand. The high dense viewing points can provide smooth motion parallax and larger image depth without blurry. The basic principle of stereoscopic display is described firstly. Then, design architectures including hardware and software are demonstrated. The system consists of a frontal projection lenticular screen, an optimally designed projector-array and a set of multi-channel image processors. The parameters of the frontal projection lenticular screen are based on the demand of viewing such as the viewing distance and the width of view zones. Each projector is arranged on an adjustable platform. The set of multi-channel image processors are made up of six PCs. One of them is used as the main controller, the other five client PCs can process 30 channel signals and transmit them to the projector-array. Then a natural 3D scene will be perceived based on the frontal projection lenticular screen with more than 1.5 m image depth in real time. The control section is presented in detail, including parallax adjustment, system synchronization, distortion correction, etc. Experimental results demonstrate the effectiveness of this novel controllable 3D display system.

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

Grant, Robert

Under this grant, three significant software packages were developed or improved, all with the goal of improving the ease-of-use of HPC libraries. The first component is a Python package, named DistArray (originally named Odin), that provides a high-level interface to distributed array computing. This interface is based on the popular and widely used NumPy package and is integrated with the IPython project for enhanced interactive parallel distributed computing. The second Python package is the Distributed Array Protocol (DAP) that enables separate distributed array libraries to share arrays efficiently without copying or sending messages. If a distributed array library supports themore » DAP, it is then automatically able to communicate with any other library that also supports the protocol. This protocol allows DistArray to communicate with the Trilinos library via PyTrilinos, which was also enhanced during this project. A third package, PyTrilinos, was extended to support distributed structured arrays (in addition to the unstructured arrays of its original design), allow more flexible distributed arrays (i.e., the restriction to double precision data was lifted), and implement the DAP. DAP support includes both exporting the protocol so that external packages can use distributed Trilinos data structures, and importing the protocol so that PyTrilinos can work with distributed data from external packages.« less

Evaluation of second-generation sequencing of 19 dilated cardiomyopathy genes for clinical applications.

PubMed

Gowrisankar, Sivakumar; Lerner-Ellis, Jordan P; Cox, Stephanie; White, Emily T; Manion, Megan; LeVan, Kevin; Liu, Jonathan; Farwell, Lisa M; Iartchouk, Oleg; Rehm, Heidi L; Funke, Birgit H

2010-11-01

Medical sequencing for diseases with locus and allelic heterogeneities has been limited by the high cost and low throughput of traditional sequencing technologies. "Second-generation" sequencing (SGS) technologies allow the parallel processing of a large number of genes and, therefore, offer great promise for medical sequencing; however, their use in clinical laboratories is still in its infancy. Our laboratory offers clinical resequencing for dilated cardiomyopathy (DCM) using an array-based platform that interrogates 19 of more than 30 genes known to cause DCM. We explored both the feasibility and cost effectiveness of using PCR amplification followed by SGS technology for sequencing these 19 genes in a set of five samples enriched for known sequence alterations (109 unique substitutions and 27 insertions and deletions). While the analytical sensitivity for substitutions was comparable to that of the DCM array (98%), SGS technology performed better than the DCM array for insertions and deletions (90.6% versus 58%). Overall, SGS performed substantially better than did the current array-based testing platform; however, the operational cost and projected turnaround time do not meet our current standards. Therefore, efficient capture methods and/or sample pooling strategies that shorten the turnaround time and decrease reagent and labor costs are needed before implementing this platform into routine clinical applications.

Target detection and localization in shallow water: an experimental demonstration of the acoustic barrier problem at the laboratory scale.

PubMed

Marandet, Christian; Roux, Philippe; Nicolas, Barbara; Mars, Jérôme

2011-01-01

This study demonstrates experimentally at the laboratory scale the detection and localization of a wavelength-sized target in a shallow ultrasonic waveguide between two source-receiver arrays at 3 MHz. In the framework of the acoustic barrier problem, at the 1/1000 scale, the waveguide represents a 1.1-km-long, 52-m-deep ocean acoustic channel in the kilohertz frequency range. The two coplanar arrays record in the time-domain the transfer matrix of the waveguide between each pair of source-receiver transducers. Invoking the reciprocity principle, a time-domain double-beamforming algorithm is simultaneously performed on the source and receiver arrays. This array processing projects the multireverberated acoustic echoes into an equivalent set of eigenrays, which are defined by their launch and arrival angles. Comparison is made between the intensity of each eigenray without and with a target for detection in the waveguide. Localization is performed through tomography inversion of the acoustic impedance of the target, using all of the eigenrays extracted from double beamforming. The use of the diffraction-based sensitivity kernel for each eigenray provides both the localization and the signature of the target. Experimental results are shown in the presence of surface waves, and methodological issues are discussed for detection and localization.

The Cosmic Ray Observatory Project in Nebraska and Public Outreach for the Pierre Auger Observatory in Argentina

NASA Astrophysics Data System (ADS)

Snow, Gregory

2005-04-01

The Cosmic Ray Observatory Project (CROP) is a statewide education and research experiment involving Nebraska high school students, teachers, and college undergraduates in the study of extensive cosmic-ray air showers. A network of high school teams construct, install, and operate school-based detectors in coordination with University of Nebraska physics professors and graduate students. The detector system at each school is an array of scintillation counters recycled from the Chicago Air Shower Array in weather-proof enclosures on the school roof, with a GPS receiver providing a time stamp for cosmic-ray events. The detectors are connected to triggering electronics and a data-acquisition PC inside the building. Students share data via the Internet to search for time coincidences with other sites. CROP has enlisted 26 schools in its first 5 years of operation with the aim of expanding to the 314 high schools in the state over the next several years. The presenter also serves as the Task Leader for Education and Outreach for the Pierre Auger Cosmic Ray Observatory, and selected public outreach activities related to the experiment will be described.

Cortical interactions in vision and awareness: hierarchies in reverse.

PubMed

Juan, Chi-Hung; Campana, Gianluca; Walsh, Vincent

2004-01-01

The anatomical connections between visual areas can be organized in 'feedforward', 'feedback' or 'horizontal' laminar patterns. We report here four experiments that test the function of some of the feedback projections in visual cortex. Projections from V5 to V1 have been suggested to be important in visual awareness, and in the first experiment we show this to be the case in the blindsight patient GY. This demonstration is replicated, in principle, in the second experiment and we also show the timing of the V5-V1 interaction to correspond to findings from single unit physiology. In the third experiment we show that V1 is important for stimulus detection in visual search arrays and that the timing of V1 interference with TMS is late (up to 240 ms after the onset of the visual array). Finally we report an experiment showing that the parietal cortex is not involved in visual motion priming, whereas V5 is, suggesting that the parietal cortex does not modulate V5 in this task. We interpret the data in terms of Bullier's recent physiological recordings and Ahissar and Hochstein's reverse hierarchy theory of vision.

Low-cost solar array project progress and plans

NASA Technical Reports Server (NTRS)

Callaghan, W. T.

1981-01-01

The considered project is part of the DOE Photovoltaic Technology and Market Development Program. This program is concerned with the development and the utilization of cost-competitive photovoltaic systems. The project has the objective to develop, by 1986, the national capability to manufacture low-cost, long-life photovoltaic arrays at production rates that will realize economies of scale, and at a price of less than $0.70/watt. The array performance objectives include an efficiency greater than 10% and an operating lifetime longer than 20 years. The objective of the silicon material task is to establish the practicality of processes for producing silicon suitable for terrestrial photovoltaic applications at a price of $14/kg. The large-area sheet task is concerned with the development of process technology for sheet formation. Low-cost encapsulation material systems are being developed in connection with the encapsulation task. Another project goal is related to the development of economical process sequences.

Solar observations with the prototype of the Brazilian Decimetric Array

NASA Astrophysics Data System (ADS)

Sawant, H. S.; Ramesh, R.; Faria, C.; Cecatto, J. R.; Fernandes, F. C. R.; Madsen, F. H. R.; Subramanian, K. R.; Sundararajan, M. S.

The prototype of the Brazilian Decimetric Array BDA consists of 5 element alt-az mounted parabolic mesh type dishes of 4-meter diameter having base lines up to 220 meters in the E--W direction The array was put into regular operation at Cachoeira Paulista Brazil longitude 45 r 00 20 W and latitude 22 r 41 19 S This array operates in the frequency range of 1 2 -- 1 7 GHz Solar observations are carried at sim 1 4 GHz in transit and tracking modes Spatial fine structures superimposed on the one dimensional brightness map of the sun associated with active regions and or with solar activity and their time evolution will be presented In the second phase of the project the frequency range will be increased to 1 2 - 1 7 2 8 and 5 6 GHz Central part of the array will consist of 26 antennas with 4-meter diameter laid out randomically in the square of 256 by 256 meter with minimum and maximum base lines of 8 and 256 meters respectively Details of this array with imaging capabilities in snap shot mode for solar observations and procedure of the phase and amplitude calibrations will be presented The development of instrument will be completed by the beginning of 2008

Measuring the hydraulic fracture-induced deformation of reservoirs and adjacent rocks employing a deeply buried inclinometer array: GRI/DOE multi-site project

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

Branagan, P.T.; Warpinski, N.R.; Engler, B.

A vertical inclinometer array consisting of six biaxial tiltmeters was cemented behind pipe at depths between 4,273 and 4,628 ft. This wide-aperture array provided real-time tilt profiles corresponding to a series of seven hydraulic fractures being conducted in a nearby offset well in a fluvial sandstone reservoir. Array profiles for three KCl water fracs indicated that height growth was confined to the gross thickness of the reservoir despite extensive fracture length extension. Long-term monitoring of the array suggests that a substantial residual frac: width remained long after fracture closure occurred. For two 400-bbl linear gel minifracs, some height growth wasmore » observed but it was not extensive. Tilt amplitudes related to expanded frac widths were found to increase as would be expected with these thicker frac fluids. When cross-linker and proppant were included in the last fracture, tilt-derived heights were seen to grow rapidly extending into the bounding layers as the more complex fluids entered the fracture system. This inclinometer array was one of several independent, yet complimentary, fracture diagnostics tools that included crosswell multilevel microseismic arrays, FRACPRO{reg_sign} and a remote fracture intersection well. Their purpose was to provide integrated field-scale data regarding hydraulic fracture dynamics and geometry that would be used to construct accurate fracture mapping and diagnostic techniques.« less

The ALPACA Project

NASA Astrophysics Data System (ADS)

Takita, Masato

2017-06-01

We have started up the ALPACA (Andes Large area PArticle detector for Cosmic ray physics and Astronomy) project. The ALPACA experiment is composed of an 83,000 m2 air shower array and a 5,400 m2 underground muon detector array to make wide field-of-view high-sensitivity observations of high-energy cosmic rays/cosmic gamma rays on the Cerro Estuqueria highland, 4,740 m above sea level around Mount Chacaltaya, Bolivia. We briefly report on the design concept of the new project and its physics targets.

SIMBIOS Project

NASA Technical Reports Server (NTRS)

Fargion, Giulietta S.; McClain, Charles R.; Busalacchi, Antonio J. (Technical Monitor)

2001-01-01

The purpose of this technical report is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities, NASA Research Announcement (NRAI) research status, satellite data processing, data product validation, and field calibration. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of validating and combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational project.

PMMW Camera TRP. Phase 1

NASA Technical Reports Server (NTRS)

1997-01-01

Passive millimeter wave (PMMW) sensors have the ability to see through fog, clouds, dust and sandstorms and thus have the potential to support all-weather operations, both military and commercial. Many of the applications, such as military transport or commercial aircraft landing, are technologically stressing in that they require imaging of a scene with a large field of view in real time and with high spatial resolution. The development of a low cost PMMW focal plane array camera is essential to obtain real-time video images to fulfill the above needs. The overall objective of this multi-year project (Phase 1) was to develop and demonstrate the capabilities of a W-band PMMW camera with a microwave/millimeter wave monolithic integrated circuit (MMIC) focal plane array (FPA) that can be manufactured at low cost for both military and commercial applications. This overall objective was met in July 1997 when the first video images from the camera were generated of an outdoor scene. In addition, our consortium partner McDonnell Douglas was to develop a real-time passive millimeter wave flight simulator to permit pilot evaluation of a PMMW-equipped aircraft in a landing scenario. A working version of this simulator was completed. This work was carried out under the DARPA-funded PMMW Camera Technology Reinvestment Project (TRP), also known as the PMMW Camera DARPA Joint Dual-Use Project. In this final report for the Phase 1 activities, a year by year description of what the specific objectives were, the approaches taken, and the progress made is presented, followed by a description of the validation and imaging test results obtained in 1997.

Supporting Current Energy Conversion Projects through Numerical Modeling

NASA Astrophysics Data System (ADS)

James, S. C.; Roberts, J.

2016-02-01

The primary goals of current energy conversion (CEC) technology being developed today are to optimize energy output and minimize environmental impact. CEC turbines generate energy from tidal and current systems and create wakes that interact with turbines located downstream of a device. The placement of devices can greatly influence power generation and structural reliability. CECs can also alter the environment surrounding the turbines, such as flow regimes, sediment dynamics, and water quality. These alterations pose potential stressors to numerous environmental receptors. Software is needed to investigate specific CEC sites to simulate power generation and hydrodynamic responses of a flow through a CEC turbine array so that these potential impacts can be evaluated. Moreover, this software can be used to optimize array layouts that yield the least changes to the environmental (i.e., hydrodynamics, sediment dynamics, and water quality). Through model calibration exercises, simulated wake profiles and turbulence intensities compare favorably to the experimental data and demonstrate the utility and accuracy of a fast-running tool for future siting and analysis of CEC arrays in complex domains. The Delft3D modeling tool facilitates siting of CEC projects through optimization of array layouts and evaluation of potential environmental effect all while provide a common "language" for academics, industry, and regulators to be able to discuss the implications of marine renewable energy projects. Given the enormity of any full-scale marine renewable energy project, it necessarily falls to modeling to evaluate how array operations must be addressed in an environmental impact statement in a way that engenders confidence in the assessment of the CEC array to minimize environmental effects.

2D mapping of the MV photon fluence and 3D dose reconstruction in real time for quality assurance during radiotherapy treatment

NASA Astrophysics Data System (ADS)

Alrowaili, Z. A.; Lerch, M. L. F.; Carolan, M.; Fuduli, I.; Porumb, C.; Petasecca, M.; Metcalfe, P.; Rosenfeld, A. B.

2015-09-01

Summary: the photon irradiation response of a 2D solid state transmission detector array mounted in a linac block tray is used to reconstruct the projected 2D dose map in a homogenous phantom along rays that diverge from the X-ray source and pass through each of the 121 detector elements. A unique diode response-to-dose scaling factor, applied to all detectors, is utilised in the reconstruction to demonstrate that real time QA during radiotherapy treatment is feasible. Purpose: to quantitatively demonstrate reconstruction of the real time radiation dose from the irradiation response of the 11×11 silicon Magic Plate (MP) detector array operated in Transmission Mode (MPTM). Methods and Materials: in transmission mode the MP is positioned in the block tray of a linac so that the central detector of the array lies on the central axis of the radiation beam. This central detector is used to determine the conversion factor from measured irradiation response to reconstructed dose at any point on the central axis within a homogenous solid water phantom. The same unique conversion factor is used for all MP detector elements lying within the irradiation field. Using the two sets of data, the 2D or 3D dose map is able to be reconstructed in the homogenous phantom. The technique we have developed is illustrated here for different depths and irradiation field sizes, (5 × 5 cm2 to 40 × 40 cm2) as well as a highly non uniform irradiation field. Results: we find that the MPTM response is proportional to the projected 2D dose map measured at a specific phantom depth, the "sweet depth". A single factor, for several irradiation field sizes and depths, is derived to reconstruct the dose in the phantom along rays projected from the photon source through each MPTM detector element. We demonstrate that for all field sizes using the above method, the 2D reconstructed and measured doses agree to within ± 2.48% (2 standard deviation) for all in-field MP detector elements. Conclusions: a 2D detector system and method to reconstruct the dose in a homogeneous phantom and in real time has been demonstrated. The success of this work is an exciting development toward real time QA during radiotherapy treatment.

Airborne laser-diode-array illuminator assessment for the night vision's airborne mine-detection arid test

NASA Astrophysics Data System (ADS)

Stetson, Suzanne; Weber, Hadley; Crosby, Frank J.; Tinsley, Kenneth; Kloess, Edmund; Nevis, Andrew J.; Holloway, John H., Jr.; Witherspoon, Ned H.

2004-09-01

The Airborne Littoral Reconnaissance Technologies (ALRT) project has developed and tested a nighttime operational minefield detection capability using commercial off-the-shelf high-power Laser Diode Arrays (LDAs). The Coastal System Station"s ALRT project, under funding from the Office of Naval Research (ONR), has been designing, developing, integrating, and testing commercial arrays using a Cessna airborne platform over the last several years. This has led to the development of the Airborne Laser Diode Array Illuminator wide field-of-view (ALDAI-W) imaging test bed system. The ALRT project tested ALDAI-W at the Army"s Night Vision Lab"s Airborne Mine Detection Arid Test. By participating in Night Vision"s test, ALRT was able to collect initial prototype nighttime operational data using ALDAI-W, showing impressive results and pioneering the way for final test bed demonstration conducted in September 2003. This paper describes the ALDAI-W Arid Test and results, along with processing steps used to generate imagery.

Concentrator enhanced solar arrays design study

NASA Technical Reports Server (NTRS)

Lott, D. R.

1978-01-01

The analysis and preliminary design of a 25 kW concentrator enhanced lightweight flexible solar array are presented. The study was organized into five major tasks: (1) assessment and specification of design requirements; (2) mechanical design; (3) electric design; (4) concentrator design; and (5) cost projection. The tasks were conducted in an iterative manner so as to best derive a baseline design selection. The objectives of the study are discussed and comparative configurations and mass data on the SEP (Solar Electric Propulsion) array design, concentrator design options and configuration/mass data on the selected concentrator enhanced solar array baseline design are presented. Design requirements supporting design analysis and detailed baseline design data are discussed. The results of the cost projection analysis and new technology are also discussed.

Earthquake source imaging by high-resolution array analysis at regional distances: the 2010 M7 Haiti earthquake as seen by the Venezuela National Seismic Network

NASA Astrophysics Data System (ADS)

Meng, L.; Ampuero, J. P.; Rendon, H.

2010-12-01

Back projection of teleseismic waves based on array processing has become a popular technique for earthquake source imaging,in particular to track the areas of the source that generate the strongest high frequency radiation. The technique has been previously applied to study the rupture process of the Sumatra earthquake and the supershear rupture of the Kunlun earthquakes. Here we attempt to image the Haiti earthquake using the data recorded by Venezuela National Seismic Network (VNSN). The network is composed of 22 broad-band stations with an East-West oriented geometry, and is located approximately 10 degrees away from Haiti in the perpendicular direction to the Enriquillo fault strike. This is the first opportunity to exploit the privileged position of the VNSN to study large earthquake ruptures in the Caribbean region. This is also a great opportunity to explore the back projection scheme of the crustal Pn phase at regional distances,which provides unique complementary insights to the teleseismic source inversions. The challenge in the analysis of the 2010 M7.0 Haiti earthquake is its very compact source region, possibly shorter than 30km, which is below the resolution limit of standard back projection techniques based on beamforming. Results of back projection analysis using the teleseismic USarray data reveal little details of the rupture process. To overcome the classical resolution limit we explored the Multiple Signal Classification method (MUSIC), a high-resolution array processing technique based on the signal-noise orthognality in the eigen space of the data covariance, which achieves both enhanced resolution and better ability to resolve closely spaced sources. We experiment with various synthetic earthquake scenarios to test the resolution. We find that MUSIC provides at least 3 times higher resolution than beamforming. We also study the inherent bias due to the interferences of coherent Green’s functions, which leads to a potential quantification of biased uncertainty of the back projection. Preliminary results from the Venezuela data set shows an East to West rupture propagation along the fault with sub-Rayleigh rupture speed, consistent with a compact source with two significant asperities which are confirmed by source time function obtained from Green’s function deconvolution and other source inversion results. These efforts could lead the Venezuela National Seismic Network to play a prominent role in the timely characterization of the rupture process of large earthquakes in the Caribbean, including the future ruptures along the yet unbroken segments of the Enriquillo fault system.

NREL Integrate: RCS-4-42326

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

Hudgins, Andrew P.; Waight, Jim; Grover, Shailendra

OMNETRIC Corp., Duke Energy, CPS Energy, and the University of Texas at San Antonio (UTSA) created a project team to execute the project 'OpenFMB Reference Architecture Demonstration.' The project included development and demonstration of concepts that will enable the electric utility grid to host larger penetrations of renewable resources. The project concept calls for the aggregation of renewable resources and loads into microgrids and the control of these microgrids with an implementation of the OpenFMB Reference Architecture. The production of power from the renewable resources that are appearing on the grid today is very closely linked to the weather. Themore » difficulty of forecasting the weather, which is well understood, leads to difficulty in forecasting the production of renewable resources. The current state of the art in forecasting the power production from renewables (solar PV and wind) are accuracies in the range of 12-25 percent NMAE. In contrast the demand for electricity aggregated to the system level, is easier to predict. The state of the art of demand forecasting done, 24 hours ahead, is about 2-3% MAPE. Forecasting the load to be supplied from conventional resources (demand minus generation from renewable resources) is thus very hard to forecast. This means that even a few hours before the time of consumption, there can be considerable uncertainty over what must be done to balance supply and demand. Adding to the problem of difficulty of forecasting, is the reality of the variability of the actual production of power from renewables. Due to the variability of wind speeds and solar insolation, the actual output of power from renewable resources can vary significantly over a short period of time. Gusts of winds result is variation of power output of wind turbines. The shadows of clouds moving over solar PV arrays result in the variation of power production of the array. This compounds the problem of balancing supply and demand in real time. Establishing a control system that can manage distribution systems with large penetrations of renewable resources is difficult due to two major issues: (1) the lack of standardization and interoperability between the vast array of equipment in operation and on the market, most of which use different and proprietary means of communication and (2) the magnitude of the network and the information it generates and consumes. The objective of this project is to provide the industry with a design concept and tools that will enable the electric power grid to overcome these barriers and support a larger penetration of clean energy from renewable resources.« less

AGILIS: Agile Guided Interferometer for Longbaseline Imaging Synthesis. Demonstration and concepts of reconfigurable optical imaging interferometers

NASA Astrophysics Data System (ADS)

Woillez, Julien; Lai, Olivier; Perrin, Guy; Reynaud, François; Baril, Marc; Dong, Yue; Fédou, Pierre

2017-06-01

Context. In comparison to the radio and sub-millimetric domains, imaging with optical interferometry is still in its infancy. Due to the limited number of telescopes in existing arrays, image generation is a demanding process that relies on time-consuming reconfiguration of the interferometer array and super-synthesis. Aims: Using single mode optical fibres for the coherent transport of light from the collecting telescopes to the focal plane, a new generation of interferometers optimized for imaging can be designed. Methods: To support this claim, we report on the successful completion of the `OHANA Iki project: an end-to-end, on-sky demonstration of a two-telescope interferometer, built around near-infrared single mode fibres, carried out as part of the `OHANA project. Results: Having demonstrated that coherent transport by single-mode fibres is feasible, we explore the concepts, performances, and limitations of a new imaging facility with single mode fibres at its heart: Agile Guided Interferometer for Longbaseline Imaging Synthesis (AGILIS). Conclusions: AGILIS has the potential of becoming a next generation facility or a precursor to a much larger project like the Planet Formation Imager (PFI).

Synthesis Study of a 6-Element Non-Uniform Array with Tilted Elements for CLARREO Project

NASA Technical Reports Server (NTRS)

Jamnejad, Vahraz; Hoorfar, Ahmad

2012-01-01

This paper presents the results of a preliminary study of the gain/pattern properties of a 6-element Radio Occultation (RO) array for the proposed CLARREO (Climate Absolute Radiance and Refractivity Observatory (CLARREO) Project. CLARREO is one of the 4 highest priority missions recommended in the National Research Council Earth Science Decadal Survey.

Real-time label-free biosensing with integrated planar waveguide ring resonators

NASA Astrophysics Data System (ADS)

Sohlström, Hans; Gylfason, Kristinn B.; Hill, Daniel

2010-05-01

We review the use of planar integrated optical waveguide ring resonators for label free bio-sensing and present recent results from two European biosensor collaborations: SABIO and InTopSens. Planar waveguide ring resonators are attractive for label-free biosensing due to their small footprint, high Q-factors, and compatibility with on-chip optics and microfluidics. This enables integrated sensor arrays for compact labs-on-chip. One application of label-free sensor arrays is for point-of-care medical diagnostics. Bringing such powerful tools to the single medical practitioner is an important step towards personalized medicine, but requires addressing a number of issues: improving limit of detection, managing the influence of temperature, parallelization of the measurement for higher throughput and on-chip referencing, efficient light-coupling strategies to simplify alignment, and packaging of the optical chip and integration with microfluidics. From the SABIO project we report refractive index measurement and label-free biosensing in an 8-channel slotwaveguide ring resonator sensor array, within a compact cartridge with integrated microfluidics. The sensors show a volume sensing detection limit of 5 x 10-6 RIU and a surface sensing detection limit of 0.9 pg/mm2. From the InTopSens project we report early results on silicon-on-insulator racetrack resonators.

Subspace-based interference removal methods for a multichannel biomagnetic sensor array.

PubMed

Sekihara, Kensuke; Nagarajan, Srikantan S

2017-10-01

In biomagnetic signal processing, the theory of the signal subspace has been applied to removing interfering magnetic fields, and a representative algorithm is the signal space projection algorithm, in which the signal/interference subspace is defined in the spatial domain as the span of signal/interference-source lead field vectors. This paper extends the notion of this conventional (spatial domain) signal subspace by introducing a new definition of signal subspace in the time domain. It defines the time-domain signal subspace as the span of row vectors that contain the source time course values. This definition leads to symmetric relationships between the time-domain and the conventional (spatial-domain) signal subspaces. As a review, this article shows that the notion of the time-domain signal subspace provides useful insights over existing interference removal methods from a unified perspective. Main results and significance. Using the time-domain signal subspace, it is possible to interpret a number of interference removal methods as the time domain signal space projection. Such methods include adaptive noise canceling, sensor noise suppression, the common temporal subspace projection, the spatio-temporal signal space separation, and the recently-proposed dual signal subspace projection. Our analysis using the notion of the time domain signal space projection reveals implicit assumptions these methods rely on, and shows that the difference between these methods results only from the manner of deriving the interference subspace. Numerical examples that illustrate the results of our arguments are provided.

Subspace-based interference removal methods for a multichannel biomagnetic sensor array

NASA Astrophysics Data System (ADS)

Sekihara, Kensuke; Nagarajan, Srikantan S.

2017-10-01

Objective. In biomagnetic signal processing, the theory of the signal subspace has been applied to removing interfering magnetic fields, and a representative algorithm is the signal space projection algorithm, in which the signal/interference subspace is defined in the spatial domain as the span of signal/interference-source lead field vectors. This paper extends the notion of this conventional (spatial domain) signal subspace by introducing a new definition of signal subspace in the time domain. Approach. It defines the time-domain signal subspace as the span of row vectors that contain the source time course values. This definition leads to symmetric relationships between the time-domain and the conventional (spatial-domain) signal subspaces. As a review, this article shows that the notion of the time-domain signal subspace provides useful insights over existing interference removal methods from a unified perspective. Main results and significance. Using the time-domain signal subspace, it is possible to interpret a number of interference removal methods as the time domain signal space projection. Such methods include adaptive noise canceling, sensor noise suppression, the common temporal subspace projection, the spatio-temporal signal space separation, and the recently-proposed dual signal subspace projection. Our analysis using the notion of the time domain signal space projection reveals implicit assumptions these methods rely on, and shows that the difference between these methods results only from the manner of deriving the interference subspace. Numerical examples that illustrate the results of our arguments are provided.

A novel optical freezing array for the examination of cooling rate dependence in heterogeneous ice nucleation

NASA Astrophysics Data System (ADS)

Budke, Carsten; Dreischmeier, Katharina; Koop, Thomas

2014-05-01

Homogeneous ice nucleation is a stochastic process, implying that it is not only temperature but also time dependent. For heterogeneous ice nucleation it is still under debate whether there is a significant time dependence or not. In case of minor time dependence it is probably sufficient to use a singular or slightly modified singular approach, which mainly supposes temperature dependence and just small stochastic variations. We contribute to this discussion using a novel optical freezing array termed BINARY (Bielefeld Ice Nucleation ARraY). The setup consists of an array of microliter-sized droplets on a Peltier cooling stage. The droplets are separated from each other with a polydimethylsiloxane (PDMS) spacer to prevent a Bergeron-Findeisen process, in which the first freezing droplets grow at the expense of the remaining liquid ones due to their vapor pressure differences. An automatic detection of nucleation events is realized optically by the change in brightness during freezing. Different types of ice nucleating agents were tested with the presented setup, e. g. pollen and clay mineral dust. Exemplarily, cooling rate dependent measurements are shown for the heterogeneous ice nucleation induced by Snomax®. The authors gratefully acknowledge funding by the German Research Foundation (DFG) through the project BIOCLOUDS (KO 2944/1-1) and through the research unit INUIT (FOR 1525) under KO 2944/2-1. We particularly thank our INUIT partners for fruitful collaboration and sharing of ideas and IN samples.

South African Student Constructed Indlebe Radio Telescope

NASA Astrophysics Data System (ADS)

McGruder, Charles H.; MacPherson, Stuart; Janse Van Vuuren, Gary Peter

2017-01-01

The Indlebe Radio Telescope (IRT) is a small transit telescope with a 5 m diameter parabolic reflector working at 21 cm. It was completely constructed by South African (SA) students from the Durban University of Technology (DUT), where it is located. First light occurred on 28 July 2008, when the galactic center, Sagittarius A, was detected. As a contribution to the International Year of Astronomy in 2009, staff members in the Department of Electronic Engineering at DUT in 2006 decided to have their students create a fully functional radio telescope by 2009. The specific project aims are to provide a visible project that could generate interest in science and technology in high school students and to provide a real world system for research in radio astronomy in general and an optimization of low noise radio frequency receiver systems in particular. These aims must be understood in terms of the SA’s government interests in radio astronomy. SA is a partner in the Square Kilometer Array (SKA) project, has constructed the Karoo Array Telescope (KAT) and MeerKat, which is the largest and most sensitive radio telescope in the southern hemisphere. SA and its partners in Africa are investing in the construction of the African Very Long Baseline Interferometry Network (AVN), an array of radio telescopes throughout Africa as an extension of the existing global Very Long Baseline Interferometry Network (VLBI). These projects will allow SA to make significant contributions to astronomy and enable astronomy to contribute to the scientific education and development goals of the country. The IRT sees on a daily basis the transit of Sag A. The transit time is influenced by precession, nutation, polar motion, aberration, celestial pole offset, proper motion, length of the terrestrial day and variable ionospheric refraction. Of these eight factors six are either predictable or measureable. To date neither celestial pole offset nor variable ionospheric refraction are predicable. Currently, we are comparing the observed transit times of Sag A with the calculable predications in order to obtain information over these two factors, with a view to better understanding them.

Space-Based Telemetry and Range Safety Project Ku-Band and Ka-Band Phased Array Antenna

NASA Technical Reports Server (NTRS)

Whiteman, Donald E.; Valencia, Lisa M.; Birr, Richard B.

2005-01-01

The National Aeronautics and Space Administration Space-Based Telemetry and Range Safety study is a multiphase project to increase data rates and flexibility and decrease costs by using space-based communications assets for telemetry during launches and landings. Phase 1 used standard S-band antennas with the Tracking and Data Relay Satellite System to obtain a baseline performance. The selection process and available resources for Phase 2 resulted in a Ku-band phased array antenna system. Several development efforts are under way for a Ka-band phased array antenna system for Phase 3. Each phase includes test flights to demonstrate performance and capabilities. Successful completion of this project will result in a set of communications requirements for the next generation of launch vehicles.

Ku- and Ka-Band Phased Array Antenna for the Space-Based Telemetry and Range Safety Project

NASA Technical Reports Server (NTRS)

Whiteman, Donald E.; Valencia, Lisa M.; Birr, Richard B.

2005-01-01

The National Aeronautics and Space Administration Space-Based Telemetry and Range Safety study is a multiphase project to increase data rates and flexibility and decrease costs by using space-based communications assets for telemetry during launches and landings. Phase 1 used standard S-band antennas with the Tracking and Data Relay Satellite System to obtain a baseline performance. The selection process and available resources for Phase 2 resulted in a Ku-band phased array antenna system. Several development efforts are under way for a Ka-band phased array antenna system for Phase 3. Each phase includes test flights to demonstrate performance and capabilities. Successful completion of this project will result in a set of communications requirements for the next generation of launch vehicles.

Liquid sodium testing of in-house phased array EMAT transducer for L-wave applications

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

Le Bourdais, F.; Le Polles, T.; Baque, F.

2015-07-01

This paper describes the development of an in-house phased array EMAT transducer for longitudinal wave inspection in liquid sodium. The work presented herein is part of an undergoing project aimed at improving in-service inspection techniques for the ASTRID reactor project. The design process of the phased array EMAT probe is briefly explained and followed by a review of experimental test results. We first present test results obtained in the laboratory while the last part of the paper describes the liquid sodium testing and the produced ultrasound images. (authors)

Single scan parameterization of space-variant point spread functions in image space via a printed array: the impact for two PET/CT scanners.

PubMed

Kotasidis, F A; Matthews, J C; Angelis, G I; Noonan, P J; Jackson, A; Price, P; Lionheart, W R; Reader, A J

2011-05-21

Incorporation of a resolution model during statistical image reconstruction often produces images of improved resolution and signal-to-noise ratio. A novel and practical methodology to rapidly and accurately determine the overall emission and detection blurring component of the system matrix using a printed point source array within a custom-made Perspex phantom is presented. The array was scanned at different positions and orientations within the field of view (FOV) to examine the feasibility of extrapolating the measured point source blurring to other locations in the FOV and the robustness of measurements from a single point source array scan. We measured the spatially-variant image-based blurring on two PET/CT scanners, the B-Hi-Rez and the TruePoint TrueV. These measured spatially-variant kernels and the spatially-invariant kernel at the FOV centre were then incorporated within an ordinary Poisson ordered subset expectation maximization (OP-OSEM) algorithm and compared to the manufacturer's implementation using projection space resolution modelling (RM). Comparisons were based on a point source array, the NEMA IEC image quality phantom, the Cologne resolution phantom and two clinical studies (carbon-11 labelled anti-sense oligonucleotide [(11)C]-ASO and fluorine-18 labelled fluoro-l-thymidine [(18)F]-FLT). Robust and accurate measurements of spatially-variant image blurring were successfully obtained from a single scan. Spatially-variant resolution modelling resulted in notable resolution improvements away from the centre of the FOV. Comparison between spatially-variant image-space methods and the projection-space approach (the first such report, using a range of studies) demonstrated very similar performance with our image-based implementation producing slightly better contrast recovery (CR) for the same level of image roughness (IR). These results demonstrate that image-based resolution modelling within reconstruction is a valid alternative to projection-based modelling, and that, when using the proposed practical methodology, the necessary resolution measurements can be obtained from a single scan. This approach avoids the relatively time-consuming and involved procedures previously proposed in the literature.

Developing an Introductory Level MIS Project in Accordance with AACSB Assurance of Learning Standard 15

ERIC Educational Resources Information Center

Schwieger, Dana

2012-01-01

As part of the introductory level management information systems (MIS) course, faculty are asked to introduce the students to MIS concepts as well as to help them develop technology-related skills benefitting them in their course work and beyond. However, with a vast array of MIS topics that could be covered and class time at a premium, it is…

Adaptive Sampling in Autonomous Marine Sensor Networks

DTIC Science & Technology

2006-06-01

Analog Processing Section A high-performance preamplifier with low noise characteristics is vital to obtaining quality sonar data. The preamplifier ...research assistantships through the Generic Ocean Array Technology Sonar (GOATS) project, contract N00014-97-1-0202 and contract N00014-05-G-0106 Delivery...Formation Behavior ..................................... 60 5 An AUV Intelligent Sensor for Real-Time Adaptive Sensing 63 5.1 A Logical Sonar Sensor

Design and fabrication of microstrip antenna arrays

NASA Technical Reports Server (NTRS)

1978-01-01

A microstrip array project was conducted to demonstrate the feasibility of designing and fabricating simple, low cost, low sidelobe phased arrays with circular disk microstrip radiating elements. Design data were presented for microstrip elements and arrays including the effects of the protective covers, the mutual interaction between elements, and stripline feed network design. Low cost multilayer laminate fabrication techniques were also investigated. Utilizing this design data two C-band low sidelobe arrays were fabricated and tested: an eight-element linear and a sixty-four element planar array. These arrays incorporated stripline Butler matrix feed networks to produce a low sidelobe broadside beam.

APSA - A new generation of photovoltaic solar arrays

NASA Technical Reports Server (NTRS)

Stella, P. M.; Kurland, R. M.

1989-01-01

This paper provides details on the Advanced Photovoltaic Solar Array (APSA) wing design, fabrication, and testing. The impact of array size change on performance and mechanical characteristics is discussed. Projections for future performance enhancements that may be expected through the use of advanced solar cells presently under development are examined.

LSSA (Low-cost Silicon Solar Array) project

NASA Technical Reports Server (NTRS)

1976-01-01

The Photovoltaic Conversion Program was established to find methods of economically generating enough electrical power to meet future requirements. Activities and progress in the following areas are discussed: silicon-refinement processes; silicon-sheet-growth techniques; encapsulants; manufacturing of off-the-shelf solar arrays; and procurement of semistandardized solar arrays.

EarthScope's Transportable Array: Advancing Eastward

NASA Astrophysics Data System (ADS)

Busby, R. W.; Vernon, F.; Newman, R. L.; Astiz, L.

2006-12-01

EarthScope's Transportable Array has installed more than 200 high-quality broadband seismic stations over the last 3 years in the western US. These stations have a nominal spacing of 70 km and are part of an eventual 400 station array that migrates from west to east at a rate of 18 stations per month. The full 400 stations will be operating by September 2007. Stations have a residence time of about 2 years before being relocated to the next site. Throughout the continental US, 1623 sites are expected to be occupied. Standardized procedures and protocols have been developed to streamline all aspects of Transportable Array operations, from siting to site construction and installation to equipment purchasing and data archiving. Earned Value Management tools keep facility installation and operation on budget and schedule. A diverse, yet efficient, infrastructure installs and maintains the Transportable Array. Sensors, dataloggers, and other equipment are received and tested by the IRIS PASSCAL Instrument Center and shipped to regional storage facilities. To engage future geoscientists in the project, students are trained to conduct field and analytical reconnaissance to identify suitable seismic station sites. Contract personnel are used for site verification; vault construction; and installation of sensors, power, and communications systems. IRIS staff manages permitting, landowner communications, and station operations and maintenance. Seismic signal quality and metadata are quality-checked at the Array Network Facility at the University of California-San Diego and simultaneously archived at the IRIS Data Management Center in Seattle. Station equipment has been specifically designed for low power, remote, unattended operation and uses diverse two-way IP communications for real-time transmission. Digital cellular services, VSAT satellite, and commercial DSL, cable or wireless transport services are employed. Automatic monitoring of status, signal quality and earthquake event detection as well as operational alarms for low voltage and water intrusion are performed by a robust data acquisition package. This software is coupled with a host of network management tools and display managers operated by the Array Network Facility to allow managers, field personnel, and network operations staff to visualize array performance in real-time and to access historical information for diagnostics. Current data recording proficiency is 99.1%, with real-time telemetry averaging about 91%. EarthScope, IRIS and the USGS are working with regional seismic network operators, both existing and newly formed, to transition some of the Transportable Array stations into regional network assets. Each region has unique circumstances and interested parties are invited to exchange ideas on how this might be accomplished in their area. Contact busby@iris.edu for more information.

Milestone Completion Report WBS 1.3.5.05 ECP/VTK-m FY17Q2 [MS-17/01] Better Dynamic Types Design SDA05-1

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

Moreland, Kenneth D.

The FY17Q2 milestone of the ECP/VTK-m project, which is the first milestone, includes the completion of design documents for the introduction of virtual methods into the VTK-m framework. Specifically, the ability from within the code of a device (e.g. GPU or Xeon Phi) to jump to a virtual method specified at run time. This change will enable us to drastically reduce the compile time and the executable code size for the VTK-m library. Our first design introduced the idea of adding virtual functions to classes that are used during algorithm execution. (Virtual methods were previously banned from the so calledmore » execution environment.) The design was straightforward. VTK-m already has the generic concepts of an “array handle” that provides a uniform interface to memory of different structures and an “array portal” that provides generic access to said memory. These array handles and portals use C++ templating to adjust them to different memory structures. This composition provides a powerful ability to adapt to data sources, but requires knowing static types. The proposed design creates a template specialization of an array portal that decorates another array handle while hiding its type. In this way we can wrap any type of static array handle and then feed it to a single compiled instance of a function. The second design focused on the mechanics of implementing virtual methods on parallel devices with a focus on CUDA. Our initial experiments on CUDA showed a very large overhead for using virtual C++ classes with virtual methods, the standard approach. Instead, we are using an alternate method provided by C that uses function pointers. With the completion of this milestone, we are able to move to the implementation of objects with virtual (like) methods. The upshot will be much faster compile times and much smaller library/executable sizes.« less

Outlook for coastal plain forests: a subregional report from the Southern Forest Futures Project

Treesearch

Kier Klepzig; Richard Shelfer; Zanethia Choice

2014-01-01

The U.S. Coastal Plain consists of seven sections: the Northern Atlantic, Eastern Atlantic, Peninsular Florida, Southern Gulf, Middle Gulf-East, Middle Gulf-West, and Western Gulf. It covers a large area, consists of a diverse array of habitats, and supports a diverse array of uses. This report presents forecasts from the Southern Forest Futures Project that are...

LIGHTWEIGHT INTEGRATED SOLAR ARRAY AND TRANSCEIVER

NASA Image and Video Library

2016-09-23

JOHN CARR, CO-PRINCIPAL INVESTIGATOR FOR NASA'S LIGHTWEIGHT INTEGRATED SOLAR ARRAY AND TRANSCEIVER PROJECT, KNEELS TO SHOW HOW ONE OF THE THIN-FILM SIDES OR "PETALS" IN WHICH PHOTO-VOLTAIC CELLS ARE EMBEDDED, IS FOLDED AND STOWED BEFORE LAUNCH. LOOKING ON DURING A DEMONSTRATION AFTER TESTING AT NEXOLVE, ARE LES JOHNSON, LEFT, ALSO CO-PRINCIPAL INVESTIGATOR, AND DARREN BOYD, RIGHT, THE RADIO FREQUENCY LEAD FOR THE PROJECT.

Glyco-Immune Diagnostic Signatures and Therapeutic Targets of Mesothelioma

DTIC Science & Technology

2015-09-01

Mesothelioma; Glycan Array; Immunoprofiles; Robotic Arrayer 16. SECURITY CLASSIFICATION OF: U 17. LIMITATION OF ABSTRACT: UU 18. NUMBER OF PAGES 19 19a...PROJECT SUMMARY: General Comments: This project involved novel technology in which biochemically synthesized glycans were robotically printed on glass...include 386 glycans and the platform was known as the PGA-400. (Figure 1) A standard robotic technology for printing a large range of

Extent of the low-velocity region in the lowermost mantle beneath the western Pacific detected by the Vietnamese Broadband Seismograph Array

NASA Astrophysics Data System (ADS)

Takeuchi, N.; Morita, Y.; Xuyen, N. D.; Zung, N. Q.

2008-03-01

We present evidence showing the extent of the low-velocity region in the lowermost mantle beneath the western Pacific. We analyzed S, sS, ScS-S, and sScS-sS travel times observed by the Vietnamese broadband seismograph array deployed as part of the Ocean Hemisphere Project. The abrupt changes in ScS-S and sScS-sS travel times suggest that the western geographical boundary of the low-velocity region is located around 140°E and is sharp (more than 4% velocity contrast within 200 km). The dependency of S and sS travel time anomalies of epicentral distances suggests that the strong low-velocity region is confined to within 400 km from the CMB (core-mantle boundary). The existence of lateral heterogeneities with a 100 km scale inside the low-velocity region is also suggested by the abrupt changes in S and ScS waveforms.

Automated Determination of Magnitude and Source Length of Large Earthquakes

NASA Astrophysics Data System (ADS)

Wang, D.; Kawakatsu, H.; Zhuang, J.; Mori, J. J.; Maeda, T.; Tsuruoka, H.; Zhao, X.

2017-12-01

Rapid determination of earthquake magnitude is of importance for estimating shaking damages, and tsunami hazards. However, due to the complexity of source process, accurately estimating magnitude for great earthquakes in minutes after origin time is still a challenge. Mw is an accurate estimate for large earthquakes. However, calculating Mw requires the whole wave trains including P, S, and surface phases, which takes tens of minutes to reach stations at tele-seismic distances. To speed up the calculation, methods using W phase and body wave are developed for fast estimating earthquake sizes. Besides these methods that involve Green's Functions and inversions, there are other approaches that use empirically simulated relations to estimate earthquake magnitudes, usually for large earthquakes. The nature of simple implementation and straightforward calculation made these approaches widely applied at many institutions such as the Pacific Tsunami Warning Center, the Japan Meteorological Agency, and the USGS. Here we developed an approach that was originated from Hara [2007], estimating magnitude by considering P-wave displacement and source duration. We introduced a back-projection technique [Wang et al., 2016] instead to estimate source duration using array data from a high-sensitive seismograph network (Hi-net). The introduction of back-projection improves the method in two ways. Firstly, the source duration could be accurately determined by seismic array. Secondly, the results can be more rapidly calculated, and data derived from farther stations are not required. We purpose to develop an automated system for determining fast and reliable source information of large shallow seismic events based on real time data of a dense regional array and global data, for earthquakes that occur at distance of roughly 30°- 85° from the array center. This system can offer fast and robust estimates of magnitudes and rupture extensions of large earthquakes in 6 to 13 min (plus source duration time) depending on the epicenter distances. It may be a promising aid for disaster mitigation right after a damaging earthquake, especially when dealing with the tsunami evacuation and emergency rescue.

Automated Determination of Magnitude and Source Extent of Large Earthquakes

NASA Astrophysics Data System (ADS)

Wang, Dun

2017-04-01

Rapid determination of earthquake magnitude is of importance for estimating shaking damages, and tsunami hazards. However, due to the complexity of source process, accurately estimating magnitude for great earthquakes in minutes after origin time is still a challenge. Mw is an accurate estimate for large earthquakes. However, calculating Mw requires the whole wave trains including P, S, and surface phases, which takes tens of minutes to reach stations at tele-seismic distances. To speed up the calculation, methods using W phase and body wave are developed for fast estimating earthquake sizes. Besides these methods that involve Green's Functions and inversions, there are other approaches that use empirically simulated relations to estimate earthquake magnitudes, usually for large earthquakes. The nature of simple implementation and straightforward calculation made these approaches widely applied at many institutions such as the Pacific Tsunami Warning Center, the Japan Meteorological Agency, and the USGS. Here we developed an approach that was originated from Hara [2007], estimating magnitude by considering P-wave displacement and source duration. We introduced a back-projection technique [Wang et al., 2016] instead to estimate source duration using array data from a high-sensitive seismograph network (Hi-net). The introduction of back-projection improves the method in two ways. Firstly, the source duration could be accurately determined by seismic array. Secondly, the results can be more rapidly calculated, and data derived from farther stations are not required. We purpose to develop an automated system for determining fast and reliable source information of large shallow seismic events based on real time data of a dense regional array and global data, for earthquakes that occur at distance of roughly 30°- 85° from the array center. This system can offer fast and robust estimates of magnitudes and rupture extensions of large earthquakes in 6 to 13 min (plus source duration time) depending on the epicenter distances. It may be a promising aid for disaster mitigation right after a damaging earthquake, especially when dealing with the tsunami evacuation and emergency rescue.

The Square Kilometre Array

NASA Technical Reports Server (NTRS)

Huynh, Minh; Lazio, Joseph

2011-01-01

The Square Kilometre Array (SKA) will be the premier instrument to study radiation at centimetre and metre wavelengths from the cosmos, and in particular neutral hydrogen, the most abundant element in the universe. The SKA will probe the dawn of galaxy formation as well as allow advances in many other areas of astronomy, such as fundamental physics, astro-biology and cosmology. The SKA will have a collecting area of up to one million square metres spread over at least 3000 km, providing a collecting area more than twenty times greater than the current largest radio telescope. Its field of view on the sky will be several tens of square degrees with potentially several large (100 square degrees) independent beams at the lower frequencies, providing a survey speed many thousands of times greater than current facilities. This paper summarises the key science drivers of the SKA and provides an update on the international project.

The Effects of Linear Microphone Array Changes on Computed Sound Exposure Level Footprints

NASA Technical Reports Server (NTRS)

Mueller, Arnold W.; Wilson, Mark R.

1997-01-01

Airport land planning commissions often are faced with determining how much area around an airport is affected by the sound exposure levels (SELS) associated with helicopter operations. This paper presents a study of the effects changing the size and composition of a microphone array has on the computed SEL contour (ground footprint) areas used by such commissions. Descent flight acoustic data measured by a fifteen microphone array were reprocessed for five different combinations of microphones within this array. This resulted in data for six different arrays for which SEL contours were computed. The fifteen microphone array was defined as the 'baseline' array since it contained the greatest amount of data. The computations used a newly developed technique, the Acoustic Re-propagation Technique (ART), which uses parts of the NASA noise prediction program ROTONET. After the areas of the SEL contours were calculated the differences between the areas were determined. The area differences for the six arrays are presented that show a five and a three microphone array (with spacing typical of that required by the FAA FAR Part 36 noise certification procedure) compare well with the fifteen microphone array. All data were obtained from a database resulting from a joint project conducted by NASA and U.S. Army researchers at Langley and Ames Research Centers. A brief description of the joint project test design, microphone array set-up, and data reduction methodology associated with the database are discussed.

A high performance cost-effective digital complex correlator for an X-band polarimetry survey.

PubMed

Bergano, Miguel; Rocha, Armando; Cupido, Luís; Barbosa, Domingos; Villela, Thyrso; Boas, José Vilas; Rocha, Graça; Smoot, George F

2016-01-01

The detailed knowledge of the Milky Way radio emission is important to characterize galactic foregrounds masking extragalactic and cosmological signals. The update of the global sky models describing radio emissions over a very large spectral band requires high sensitivity experiments capable of observing large sky areas with long integration times. Here, we present the design of a new 10 GHz (X-band) polarimeter digital back-end to map the polarization components of the galactic synchrotron radiation field of the Northern Hemisphere sky. The design follows the digital processing trends in radio astronomy and implements a large bandwidth (1 GHz) digital complex cross-correlator to extract the Stokes parameters of the incoming synchrotron radiation field. The hardware constraints cover the implemented VLSI hardware description language code and the preliminary results. The implementation is based on the simultaneous digitized acquisition of the Cartesian components of the two linear receiver polarization channels. The design strategy involves a double data rate acquisition of the ADC interleaved parallel bus, and field programmable gate array device programming at the register transfer mode. The digital core of the back-end is capable of processing 32 Gbps and is built around an Altera field programmable gate array clocked at 250 MHz, 1 GSps analog to digital converters and a clock generator. The control of the field programmable gate array internal signal delays and a convenient use of its phase locked loops provide the timing requirements to achieve the target bandwidths and sensitivity. This solution is convenient for radio astronomy experiments requiring large bandwidth, high functionality, high volume availability and low cost. Of particular interest, this correlator was developed for the Galactic Emission Mapping project and is suitable for large sky area polarization continuum surveys. The solutions may also be adapted to be used at signal processing subsystem levels for large projects like the square kilometer array testbeds.

Development of optics with micro-LED arrays for improved opto-electronic neural stimulation

NASA Astrophysics Data System (ADS)

Chaudet, Lionel; Neil, Mark; Degenaar, Patrick; Mehran, Kamyar; Berlinguer-Palmini, Rolando; Corbet, Brian; Maaskant, Pleun; Rogerson, David; Lanigan, Peter; Bamberg, Ernst; Roska, Botond

2013-03-01

The breakthrough discovery of a nanoscale optically gated ion channel protein, Channelrhodopsin 2 (ChR2), and its combination with a genetically expressed ion pump, Halorhodopsin, allowed the direct stimulation and inhibition of individual action potentials with light alone. This work reports developments of ultra-bright elec­ tronically controlled optical array sources with enhanced light gated ion channels and pumps for use in systems to further our understanding of both brain and visual function. This work is undertaken as part of the European project, OptoNeuro. Micro-LED arrays permit spatio-temporal control of neuron stimulation on sub-millisecond timescales. However they are disadvantaged by their broad spatial light emission distribution and low fill factor. We present the design and implementation of a projection and micro-optics system for use with a micro-LED array consisting of a 16x16 matrix of 25 μm diameter micro-LEDs with 150 μm centre-to-centre spacing and an emission spectrum centred at 470 nm overlapping the peak sensitivity of ChR2 and its testing on biological samples. The projection system images the micro-LED array onto micro-optics to improve the fill-factor from ~2% to more than 78% by capturing a larger fraction of the LED emission and directing it correctly to the sample plane. This approach allows low fill factor arrays to be used effectively, which in turn has benefits in terms of thermal management and electrical drive from CMOS backplane electronics. The entire projection system is integrated into a microscope prototype to provide stimulation spots at the same size as the neuron cell body (μ10 pm).

Compendium of Instrumentation Whitepapers on Frontier Physics Needs for Snowmass 2013

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

Lipton, R.

2013-01-01

Contents of collection of whitepapers include: Operation of Collider Experiments at High Luminosity; Level 1 Track Triggers at HL-LHC; Tracking and Vertex Detectors for a Muon Collider; Triggers for hadron colliders at the energy frontier; ATLAS Upgrade Instrumentation; Instrumentation for the Energy Frontier; Particle Flow Calorimetry for CMS; Noble Liquid Calorimeters; Hadronic dual-readout calorimetry for high energy colliders; Another Detector for the International Linear Collider; e+e- Linear Colliders Detector Requirements and Limitations; Electromagnetic Calorimetry in Project X Experiments The Project X Physics Study; Intensity Frontier Instrumentation; Project X Physics Study Calorimetry Report; Project X Physics Study Tracking Report; The LHCbmore » Upgrade; Neutrino Detectors Working Group Summary; Advanced Water Cherenkov R&D for WATCHMAN; Liquid Argon Time Projection Chamber (LArTPC); Liquid Scintillator Instrumentation for Physics Frontiers; A readout architecture for 100,000 pixel Microwave Kinetic In- ductance Detector array; Instrumentation for New Measurements of the Cosmic Microwave Background polarization; Future Atmospheric and Water Cherenkov ?-ray Detectors; Dark Energy; Can Columnar Recombination Provide Directional Sensitivity in WIMP Search?; Instrumentation Needs for Detection of Ultra-high Energy Neu- trinos; Low Background Materials for Direct Detection of Dark Matter; Physics Motivation for WIMP Dark Matter Directional Detection; Solid Xenon R&D at Fermilab; Ultra High Energy Neutrinos; Instrumentation Frontier: Direct Detection of WIMPs; nEXO detector R&D; Large Arrays of Air Cherenkov Detectors; and Applications of Laser Interferometry in Fundamental Physics Experiments.« less

IRIS Arrays: Observing Wavefields at Multiple Scales and Frequencies

NASA Astrophysics Data System (ADS)

Sumy, D. F.; Woodward, R.; Frassetto, A.

2014-12-01

The Incorporated Research Institutions for Seismology (IRIS) provides instruments for creating and operating seismic arrays at a wide range of scales. As an example, for over thirty years the IRIS PASSCAL program has provided instruments to individual Principal Investigators to deploy arrays of all shapes and sizes on every continent. These arrays have ranged from just a few sensors to hundreds or even thousands of sensors, covering areas with dimensions of meters to thousands of kilometers. IRIS also operates arrays directly, such as the USArray Transportable Array (TA) as part of the EarthScope program. Since 2004, the TA has rolled across North America, at any given time spanning a swath of approximately 800 km by 2,500 km, and thus far sampling 2% of the Earth's surface. This achievement includes all of the lower-48 U.S., southernmost Canada, and now parts of Alaska. IRIS has also facilitated specialized arrays in polar environments and on the seafloor. In all cases, the data from these arrays are freely available to the scientific community. As the community of scientists who use IRIS facilities and data look to the future they have identified a clear need for new array capabilities. In particular, as part of its Wavefields Initiative, IRIS is exploring new technologies that can enable large, dense array deployments to record unaliased wavefields at a wide range of frequencies. Large-scale arrays might utilize multiple sensor technologies to best achieve observing objectives and optimize equipment and logistical costs. Improvements in packaging and power systems can provide equipment with reduced size, weight, and power that will reduce logistical constraints for large experiments, and can make a critical difference for deployments in harsh environments or other situations where rapid deployment is required. We will review the range of existing IRIS array capabilities with an overview of previous and current deployments and examples of data and results. We will review existing IRIS projects that explore new array capabilities and highlight future directions for IRIS instrumentation facilities.

SKS splitting results in central Italy and Dinaric region inside the AlpArray-CASE project

NASA Astrophysics Data System (ADS)

Salimbeni, S.; Prevolnik, S.; Pondrelli, S.; Molinari, I.; Stipcevic, J.; Kissling, E.; Šipka, V.; Herak, M.

2017-12-01

In the framework of the AlpArray project (AlpArray Seismic Network, 2015), the complementary "Central Adriatic Seismic Experiment" (CASE; AlpArray Seismic Network, 2016) was established as collaboration between ETH Zürich, University of Zagreb, INGV and Republic Hydrometeorological Service of Republic of Srpska. The CASE project consists of 9 temporary stations, installed in October 2016, located in Bosnia and Herzegovina, Croatia and Italy. Temporary broadband seismic stations, with the permanent stations present in the region shared by the Croatian Seismological Service and INGV, make an almost continuous transect cutting the Central-Southern Appenines, the central Adriatic region, central External Dinarides and finishing at the eastern margin of the Internal Dinarides. The presence of the the Apenninic and Dinarides slabs, verging in opposite directions and plunging along the opposite sides of the Adriatic plate, make this area a peculiar spot to understand the complex dynamic of the region. Various tomographic images (e.g. Bijwaard and Spakman, 2000; Piromallo and Morelli, 2003) shows not continuous slabs under the Appenines and the Dinarides, suggesting the presence of slab-gaps right beneath the region covered by the CASE experiment. Here we present the preliminary results of the SKS splitting analysis performed on the data recorded by the temporary and permanent seismic stations included in the CASE project. The new results, in combination with previous interpretation, will provide clues about how Northern and Southern Apennines are connected at depth, how the slab rollback of the Apennines thrust belt acted and if and how the Apennines are in relation with the Dinaric region. Together with the measurements from previous studies and from the AlpArray project, our new data will support the mapping of the seismic anisotropy deformation pattern from Western Alps to Pannonian region.

Dot-Projection Photogrammetry and Videogrammetry of Gossamer Space Structures

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Black, Jonathan T.; Blandino, Joseph R.; Jones, Thomas W.; Danehy, Paul M.; Dorrington, Adrian A.

2003-01-01

This paper documents the technique of using hundreds or thousands of projected dots of light as targets for photogrammetry and videogrammetry of gossamer space structures. Photogrammetry calculates the three-dimensional coordinates of each target on the structure, and videogrammetry tracks the coordinates versus time. Gossamer structures characteristically contain large areas of delicate, thin-film membranes. Examples include solar sails, large antennas, inflatable solar arrays, solar power concentrators and transmitters, sun shields, and planetary balloons and habitats. Using projected-dot targets avoids the unwanted mass, stiffness, and installation costs of traditional retroreflective adhesive targets. Four laboratory applications are covered that demonstrate the practical effectiveness of white-light dot projection for both static-shape and dynamic measurement of reflective and diffuse surfaces, respectively. Comparisons are made between dot-projection videogrammetry and traditional laser vibrometry for membrane vibration measurements. The paper closes by introducing a promising extension of existing techniques using a novel laser-induced fluorescence approach.

SIMBIOS Project 1999 Annual Report

NASA Technical Reports Server (NTRS)

McClain, Charles R.; Fargion, Giulietta S.

1999-01-01

The purpose of this technical memorandum is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities, NASA Research Announcement (NRA) research status, satellite data processing, data product validation, and field calibration. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational project.

SIMBIOS Project 1998 Annual Report

NASA Technical Reports Server (NTRS)

McClain, Charles R.; Fargion, Giulietta, S.

1999-01-01

The purpose of this series of technical reports is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Ocean Studies (SIMBIOS) Project activities, NASA Research Announcement (NRA) research status, satellite data processing, data product validation and field calibration. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant to substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issues by an operational project.

The Jet Propulsion Laboratory low-cost solar array project, 1974-1986

NASA Technical Reports Server (NTRS)

Maycock, P. D.

1986-01-01

The overall objective of the photovoltaic program is to ensure that photovoltaic conversion systems play a significant role in the nation's energy supply by stimulating an industry capable of providing approximately 50 GWe of installed electricity generating capacity by the year 2000. In order to achieve this overall objective, several time-phased program goals have been defined. Near-term goals are to achieve photovoltaic flat-plate module or concentrator array prices of $2 per peak watt (1975 dollars) at an annual production rate of 20 peak megawatts in 1982. At this price level, energy costs should range from 100 to 200 mills/kwh. Mid-term goals are to achieve photovoltaic flat-plate module or concentrator array prices of $0.50 per peak watt (in 1975 dollars), and an annual production rate of 500 peak megawatts in 1986. Studies project that photovoltaic systems will begin to compete for both distributed and larger load-center utility-type applications and thereby open up significant markets for large-scale photovoltaic systems. Far term goals are to achieve the photovoltaic flat-plate module or concentrator array price goal of $0.10 to $0.30 per peak watt in 1990 (in 1975 dollars), and an annual production rate of 10 to 20 peak gigawatts in 2000. At this price range, energy cost should be in the range of 40 to 60 mills. kwh and be cost effective for utility applications. Achievement of these goals can make photovoltaic systems economically competitive with other energy sources for dispersed on-site applications as well as for central power generation.

MeerKAT Science: On the Pathway to the SKA

NASA Astrophysics Data System (ADS)

MeerKAT Science: On the Pathway to the SKA. MeerKAT is a next generation radio telescope under construction on the African SKA central site in the Karoo plateau of South Africa. When completed in 2017 MeerKAT will be a 64-element array of 13.5-m parabolic antennas distributed over an area with a diameter of 8 km. With a combination of wide bandwidth and field of view, with the large number of antennas and total collecting area, MeerKAT will be one of the world’s most powerful imaging telescopes operating at GHz frequencies. MeerKAT is a science and technology precursor of the SKA mid-frequency dish array, and following several years of operation as a South African telescope will be incorporated into the SKA phase-one facility. The MeerKAT science program will consist of a combination of key science, legacy-style, large survey projects, and smaller projects based on proposals for open time. This workshop, which took place in Stellenbosch in the Western Cape, was held to discuss and plan the broad range of scientific investigations that will be undertaken during the pre-SKA phase of MeerKAT. Topics covered included: technical development and roll out of the MeerKAT science capabilities, details of the large survey projects presented by the project teams, science program concepts for open time, commensal programs such as the Search for Extraterrestrial Intelligence, and the impact of MeerKAT on global Very Long Baseline Interferometry. These proceedings serve as a record of the scientific vision of MeerKAT in the year before its completion, foreshadowing a new era of radio astronomy on the African continent.

Brazilian Decimetric Array (BDA) project - Phase II

NASA Astrophysics Data System (ADS)

Faria, C.; Stephany, S.; Sawant, H. S.; Cecatto, J. R.; Fernandes, F. C. R.

2010-02-01

The configuration of the second phase of the Brazilian Decimetric Array (BDA), installed at Cachoeira Paulista, Brazil (Longitude 45° 0‧ 20″ W and Latitude 22° 41‧ 19″ S), is a T-shaped array where 21 antennas are being added to existing 5 antennas of the first phase. In the third phase, in each arm of the T array, four more antennas will be added and baselines will be increased to 2.5 × 1.25 km in east-west and south directions, respectively. The antennas will be equally spaced at the distances of 250 meters from the central antenna of the T-array. Also, the frequency range will be increased to 1.2-1.7, 2.8 and 5.6 GHz. The Second phase of the BDA should be operational by the middle of 2010 and will operate in the frequency range of (1.2-1.7) GHz for solar and non solar observations. Here, we present the characteristics of the second phase of the BDA project, details of the array configuration, the u-v coverage, the synthesized beam obtained for the proposed configuration.

Plenoptic projection fluorescence tomography.

PubMed

Iglesias, Ignacio; Ripoll, Jorge

2014-09-22

A new method to obtain the three-dimensional localization of fluorochrome distributions in micrometric samples is presented. It uses a microlens array coupled to the image port of a standard microscope to obtain tomographic data by a filtered back-projection algorithm. Scanning of the microlens array is proposed to obtain a dense data set for reconstruction. Simulation and experimental results are shown and the implications of this approach in fast 3D imaging are discussed.

Proposed biomimetic molecular sensor array for astrobiology applications

NASA Astrophysics Data System (ADS)

Cullen, D. C.; Grant, W. D.; Piletsky, S.; Sims, M. R.

2001-08-01

A key objective of future astrobiology lander missions, e.g. to Mars and Europa, is the detection of biomarkers - molecules whose presence indicates the existence of either current or extinct life. To address limitations of current analytical methods for biomarker detection, we describe the methodology of a new project for demonstration of a robust molecular-recognition sensor array for astrobiology biomarkers. The sensor array will be realised by assembling components that have been demonstrated individually in previous or current research projects. The major components are (1) robust artificial molecular receptors comprised of molecular imprinted polymer (MIP) recognition systems and (2) a sensor array comprised of both optical and electrochemical sensor elements. These components will be integrated together using ink-jet printing technology coupled with in situ photo-polymerisation of MIPs. For demonstration, four model biomarkers are chosen as targets and represent various classes of potential biomarkers. Objectives of the proposed work include (1) demonstration of practical proof-of-concept, (2) identify areas for further development and (3) provide performance and design data for follow-up projects leading to astrobiology missions.

Laser diode arrays for naval reconnaissance

NASA Astrophysics Data System (ADS)

Holloway, John H., Jr.; Crosby, Frank J.; Petee, Danny A.; Suiter, Harold R.; Witherspoon, Ned H.

2003-09-01

The Airborne Littoral Reconnaissance Technologies (ALRT) Project has demonstrated a nighttime operational minefield detection capability using commercial off-the-shelf high-power Laser Diode Arrays (LDAs). Historically, optical aerial detection of minefields has primarily been limited to daytime operations but LDAs promise compact and efficient lighting to allow for enhanced reconnaissance operations for future mine detection systems. When combined with high-resolution intensified imaging systems, LDAs can illuminate otherwise unseen areas. Future wavelength options will open the way for active multispectral imaging with LDAs. The Coastal Systems Station working for the Office of Naval Research on the ALRT project has designed, developed, integrated, and tested both prototype and commercial arrays from a Cessna airborne platform. Detailed test results show the ability to detect several targets of interest in a variety of background conditions. Initial testing of the prototype arrays, reported on last year, was completed and further investigations of the commercial versions were performed. Polarization-state detection studies were performed, and advantageous properties of the source-target-sensor geometry noted. Current project plans are to expand the field-of-view coverage for Naval exercises in the summer of 2003. This paper describes the test collection, data library products, array information, on-going test analysis results, and future planned testing of the LDAs.

Quantum Computation Using Optically Coupled Quantum Dot Arrays

NASA Technical Reports Server (NTRS)

Pradhan, Prabhakar; Anantram, M. P.; Wang, K. L.; Roychowhury, V. P.; Saini, Subhash (Technical Monitor)

1998-01-01

A solid state model for quantum computation has potential advantages in terms of the ease of fabrication, characterization, and integration. The fundamental requirements for a quantum computer involve the realization of basic processing units (qubits), and a scheme for controlled switching and coupling among the qubits, which enables one to perform controlled operations on qubits. We propose a model for quantum computation based on optically coupled quantum dot arrays, which is computationally similar to the atomic model proposed by Cirac and Zoller. In this model, individual qubits are comprised of two coupled quantum dots, and an array of these basic units is placed in an optical cavity. Switching among the states of the individual units is done by controlled laser pulses via near field interaction using the NSOM technology. Controlled rotations involving two or more qubits are performed via common cavity mode photon. We have calculated critical times, including the spontaneous emission and switching times, and show that they are comparable to the best times projected for other proposed models of quantum computation. We have also shown the feasibility of accessing individual quantum dots using the NSOM technology by calculating the photon density at the tip, and estimating the power necessary to perform the basic controlled operations. We are currently in the process of estimating the decoherence times for this system; however, we have formulated initial arguments which seem to indicate that the decoherence times will be comparable, if not longer, than many other proposed models.

Sweetwater, Texas Large N Experiment

NASA Astrophysics Data System (ADS)

Sumy, D. F.; Woodward, R.; Barklage, M.; Hollis, D.; Spriggs, N.; Gridley, J. M.; Parker, T.

2015-12-01

From 7 March to 30 April 2014, NodalSeismic, Nanometrics, and IRIS PASSCAL conducted a collaborative, spatially-dense seismic survey with several thousand nodal short-period geophones complemented by a backbone array of broadband sensors near Sweetwater, Texas. This pilot project demonstrates the efficacy of industry and academic partnerships, and leveraged a larger, commercial 3D survey to collect passive source seismic recordings to image the subsurface. This innovative deployment of a large-N mixed-mode array allows industry to explore array geometries and investigate the value of broadband recordings, while affording academics a dense wavefield imaging capability and an operational model for high volume instrument deployment. The broadband array consists of 25 continuously-recording stations from IRIS PASSCAL and Nanometrics, with an array design that maximized recording of horizontal-traveling seismic energy for surface wave analysis over the primary target area with sufficient offset for imaging objectives at depth. In addition, 2639 FairfieldNodal Zland nodes from NodalSeismic were deployed in three sub-arrays: the outlier, backbone, and active source arrays. The backbone array consisted of 292 nodes that covered the entire survey area, while the outlier array consisted of 25 continuously-recording nodes distributed at a ~3 km distance away from the survey perimeter. Both the backbone and outlier array provide valuable constraints for the passive source portion of the analysis. This project serves as a learning platform to develop best practices in the support of large-N arrays with joint industry and academic expertise. Here we investigate lessons learned from a facility perspective, and present examples of data from the various sensors and array geometries. We will explore first-order results from local and teleseismic earthquakes, and show visualizations of the data across the array. Data are archived at the IRIS DMC under stations codes XB and 1B.

NEMO-SMO acoustic array: A deep-sea test of a novel acoustic positioning system for a km3-scale underwater neutrino telescope

NASA Astrophysics Data System (ADS)

Viola, S.; Ardid, M.; Bertin, V.; Enzenhöfer, A.; Keller, P.; Lahmann, R.; Larosa, G.; Llorens, C. D.; NEMO Collaboration; SMO Collaboration

2013-10-01

Within the activities of the NEMO project, the installation of a 8-floors tower (NEMO-Phase II) at a depth of 3500 m is foreseen in 2012. The tower will be installed about 80 km off-shore Capo Passero, in Sicily. On board the NEMO tower, an array of 18 acoustic sensors will be installed, permitting acoustic detection of biological sources, studies for acoustic neutrino detection and primarily acoustic positioning of the underwater structures. For the latter purpose, the sensors register acoustic signals emitted by five acoustic beacons anchored on the sea-floor. The data acquisition system of the acoustic sensors is fully integrated with the detector data transport system and is based on an “all data to shore” philosophy. Signals coming from hydrophones are continuously sampled underwater at 192 kHz/24 bit and transmitted to shore through an electro-optical cable for real-time analysis. A novel technology for underwater GPS time-stamping of data has been implemented and tested. The operation of the acoustic array will permit long-term test of sensors and electronics technologies that are proposed for the acoustic positioning system of KM3NeT.

The NSF Earthscope USArray Instrumentation Network

NASA Astrophysics Data System (ADS)

Davis, G. A.; Vernon, F.

2012-12-01

Since 2004, the Transportable Array component of the USArray Instrumentation Network has collected high resolution seismic data in near real-time from over 400 geographically distributed seismic stations. The deployed footprint of the array has steadily migrated across the continental United States, starting on the west coast and gradually moving eastward. As the network footprint shifts, stations from various regional seismic networks have been incorporated into the dataset. In 2009, an infrasound and barometric sensor component was added to existing core stations and to all new deployments. The ongoing success of the project can be attributed to a number of factors, including reliable communications to each site, on-site data buffering, largely homogenous data logging hardware, and a common phase-locked time reference between all stations. Continuous data quality is ensured by thorough human and automated review of data from the primary sensors and over 24 state-of-health parameters from each station. The staff at the Array Network Facility have developed a number of tools to visualize data and troubleshoot problematic stations remotely. In the event of an emergency or maintenance on the server hardware, data acquisition can be shifted to alternate data centers through the use of virtualization technologies.

Distributed Learning, Extremum Seeking, and Model-Free Optimization for the Resilient Coordination of Multi-Agent Adversarial Groups

DTIC Science & Technology

2016-09-07

been demonstrated on maximum power point tracking for photovoltaic arrays and for wind turbines . 3. ES has recently been implemented on the Mars...high-dimensional optimization problems . Extensions and applications of these techniques were developed during the realization of the project. 15...studied problems of dynamic average consensus and a class of unconstrained continuous-time optimization algorithms for the coordination of multiple

Remote sensing change detection tools for natural resource managers: Understanding concepts and tradeoffs in the design of landscape monitoring projects

Treesearch

Robert E. Kennedy; Philip A. Townsend; John E. Gross; Warren B. Cohen; Paul Bolstad; Wang Y. Q.; Phyllis Adams

2009-01-01

Remote sensing provides a broad view of landscapes and can be consistent through time, making it an important tool for monitoring and managing protected areas. An impediment to broader use of remote sensing science for monitoring has been the need for resource managers to understand the specialized capabilities of an ever-expanding array of image sources and analysis...

Pulsars Probe the Low-Frequency Gravitational Sky: Pulsar Timing Arrays Basics and Recent Results

NASA Astrophysics Data System (ADS)

Tiburzi, Caterina

2018-03-01

Pulsar Timing Array experiments exploit the clock-like behaviour of an array of millisecond pulsars, with the goal of detecting low-frequency gravitational waves. Pulsar Timing Array experiments have been in operation over the last decade, led by groups in Europe, Australia, and North America. These experiments use the most sensitive radio telescopes in the world, extremely precise pulsar timing models and sophisticated detection algorithms to increase the sensitivity of Pulsar Timing Arrays. No detection of gravitational waves has been made to date with this technique, but Pulsar Timing Array upper limits already contributed to rule out some models of galaxy formation. Moreover, a new generation of radio telescopes, such as the Five hundred metre Aperture Spherical Telescope and, in particular, the Square Kilometre Array, will offer a significant improvement to the Pulsar Timing Array sensitivity. In this article, we review the basic concepts of Pulsar Timing Array experiments, and discuss the latest results from the established Pulsar Timing Array collaborations.

The Virtual Earth-Solar Observatory of the SCiESMEX

NASA Astrophysics Data System (ADS)

De la Luz, V.; Gonzalez-Esparza, A.; Cifuentes-Nava, G.

2015-12-01

The Mexican Space Weather Service (SCiESMEX, http://www.sciesmex.unam.mx) started operations in October 2014. The project includes the Virtual Earth-Solar Observatory (VESO, http://www.veso.unam.mx). The VESO is a improved project wich objetive is integrate the space weather instrumentation network from the National Autonomous University of Mexico (UNAM). The network includes the Mexican Array Radiotelescope (MEXART), the Callisto receptor (MEXART), a Neutron Telescope, a Cosmic Ray Telescope. the Schumann Antenna, the National Magnetic Service, and the mexican GPS network (TlalocNet). The VESO facility is located at the Geophysics Institute campus Michoacan (UNAM). We offer the service of data store, real-time data, and quasi real-time data. The hardware of VESO includes a High Performance Computer (HPC) dedicated specially to big data storage.

Flat-plate solar array project. Volume 5: Process development

NASA Technical Reports Server (NTRS)

Gallagher, B.; Alexander, P.; Burger, D.

1986-01-01

The goal of the Process Development Area, as part of the Flat-Plate Solar Array (FSA) Project, was to develop and demonstrate solar cell fabrication and module assembly process technologies required to meet the cost, lifetime, production capacity, and performance goals of the FSA Project. R&D efforts expended by Government, Industry, and Universities in developing processes capable of meeting the projects goals during volume production conditions are summarized. The cost goals allocated for processing were demonstrated by small volume quantities that were extrapolated by cost analysis to large volume production. To provide proper focus and coverage of the process development effort, four separate technology sections are discussed: surface preparation, junction formation, metallization, and module assembly.

Phased Array Mirror Extendible Large Aperture (PAMELA) Optics Adjustment

NASA Technical Reports Server (NTRS)

1995-01-01

Scientists at Marshall's Adaptive Optics Lab demonstrate the Wave Front Sensor alignment using the Phased Array Mirror Extendible Large Aperture (PAMELA) optics adjustment. The primary objective of the PAMELA project is to develop methods for aligning and controlling adaptive optics segmented mirror systems. These systems can be used to acquire or project light energy. The Next Generation Space Telescope is an example of an energy acquisition system that will employ segmented mirrors. Light projection systems can also be used for power beaming and orbital debris removal. All segmented optical systems must be adjusted to provide maximum performance. PAMELA is an on going project that NASA is utilizing to investigate various methods for maximizing system performance.

Monitoring of Space and Earth electromagnetic environment by MAGDAS project: Collaboration with IKIR - Introduction to ICSWSE/MAGDAS project

NASA Astrophysics Data System (ADS)

Yoshikawa, Akimasa; Fujimoto, Akiko; Ikeda, Akihiro; Uozumi, Teiji; Abe, Shuji

2017-10-01

For study of coupling processes in the Solar-Terrestrial System, International Center for Space Weather Science and Education (ICSWSE), Kyushu University has developed a real time magnetic data acquisition system (the MAGDAS project) around the world. The number of observational sites is increasing every year with the collaboration of host countries. Now at this time, the MAGDAS Project has installed 78 real time magnetometers - so it is the largest magnetometer array in the world. The history of global observation at Kyushu University is over 30 years and number of developed observational sites is over 140. Especially, Collaboration between IKIR is extended back to 1990's. Now a time, we are operating Flux-gate magnetometer and FM-CW Radar. It is one of most important collaboration for space weather monitoring. By using MAGDAS data, ICSWSE produces many types of space weather index, such as EE-index (for monitoring long tern and shot term variation of equatorial electrojet), Pc5 index (for monitoring solar-wind velocity and high energy electron flux), Sq-index (for monitoring global change of ionospheric low and middle latitudinal current system), and Pc3 index (for monitoring of plasma density variation at low latitudes). In this report, we will introduce recent development of MAGDAS/ICSWSE Indexes project and topics for new open policy for MAGDAS data will be also discussed.

The research on multi-projection correction based on color coding grid array

NASA Astrophysics Data System (ADS)

Yang, Fan; Han, Cheng; Bai, Baoxing; Zhang, Chao; Zhao, Yunxiu

2017-10-01

There are many disadvantages such as lower timeliness, greater manual intervention in multi-channel projection system, in order to solve the above problems, this paper proposes a multi-projector correction technology based on color coding grid array. Firstly, a color structured light stripe is generated by using the De Bruijn sequences, then meshing the feature information of the color structured light stripe image. We put the meshing colored grid intersection as the center of the circle, and build a white solid circle as the feature sample set of projected images. It makes the constructed feature sample set not only has the perceptual localization, but also has good noise immunity. Secondly, we establish the subpixel geometric mapping relationship between the projection screen and the individual projectors by using the structure of light encoding and decoding based on the color array, and the geometrical mapping relation is used to solve the homography matrix of each projector. Lastly the brightness inconsistency of the multi-channel projection overlap area is seriously interfered, it leads to the corrected image doesn't fit well with the observer's visual needs, and we obtain the projection display image of visual consistency by using the luminance fusion correction algorithm. The experimental results show that this method not only effectively solved the problem of distortion of multi-projection screen and the issue of luminance interference in overlapping region, but also improved the calibration efficient of multi-channel projective system and reduced the maintenance cost of intelligent multi-projection system.

Heterogeneous Structure and Seismicity beneath the Tokyo Metropolitan Area

NASA Astrophysics Data System (ADS)

Nakagawa, S.; Kato, A.; Sakai, S.; Nanjo, K.; Panayotopoulos, Y.; Kurashimo, E.; Obara, K.; Kasahara, K.; Aketagawa, T.; Kimura, H.; Hirata, N.

2010-12-01

Beneath the Tokyo metropolitan area, the Philippine Sea Plate (PSP) subducts and causes damaged mega-thrust earthquakes. Sato et al. (2005) revealed the geometry of upper surface of PSP, and Hagiwara et al. (2006) estimated the velocity structure beneath Boso peninsula. However, these results are not sufficient for the assessment of the entire picture of the seismic hazards beneath the Tokyo metropolitan area including those due to an intra-slab M7+ earthquake. So, we launched the Special Project for Earthquake Disaster Mitigation in the Tokyo Metropolitan area (Hirata et al., 2009). Proving the more detailed geometry and physical properties (e.g. velocities, densities, attenuation) and stress field within PSP is very important to attain this issue. The core item of this project is a dense seismic array called Metropolitan Seismic Observation network (MeSO-net) for making observations in the metropolitan area (Sakai and Hirata, 2009; Kasahara et al., 2009). We deployed the 249 seismic stations with a spacing of 5 km. Some parts of stations construct 5 linear arrays at interval of 2 km such as Tsukuba-Fujisawa (TF) array, etc. The TF array runs from northeast to southwest through the center of Tokyo. In this study, we applied the tomography method to image the heterogeneous structure under the Tokyo metropolitan area. We selected events from the Japan Meteorological Agency (JMA) unified earthquake list. All data of MeSO-net were edited into event data by the selected JMA unified earthquake list. We picked the P and S wave arrival times. The total number of stations and events are 421 and 1,256, respectively. Then, we applied the double-difference tomography method (Zhang and Thurber, 2003) to this dataset and estimated the fine-scale velocity structure. The grid nodes locate 10 km interval in parallel with the array, 20 km interval in perpendicular to the array; and on depth direction, 5 km interval to a depth of less than 50 km and 10 km interval at a depth of more. We used 158,930 (P wave) and 149,308 (S wave) absolute arrival times, and 374,072 (P wave) and 354,912 (S wave) differential travel times. The initial velocity structure is the JMA2001 (Ueno et al., 2001), and the Vp/Vs ratio is set to 1.73 for all grid nodes. We imaged the subducting PSP and Pacific Plate clearly. The depth section of P-wave velocity structure along the TF array clearly shows that thin low-velocity layer which overlies high-velocity layer subducts towards northeast. This low-velocity layer corresponds to the oceanic crust of the subducting PSP. The obtained tomograms combined with seismicity and focal mechanisms indicate that the interior of the subducting PSP is characterized by heterogeneous structures, which could exert a profound influence on the genesis of intra-slab earthquakes. Acknowledgement: This study was supported by the Earthquake Research Institute cooperative research program.

The NASA Smart Probe Project for real-time multiple microsensor tissue recognition

NASA Technical Reports Server (NTRS)

Andrews, Russell J.; Mah, Robert W.

2003-01-01

BACKGROUND: Remote surgery requires automated sensors, effectors and sensor-effector communication. The NASA Smart Probe Project has focused on the sensor aspect. METHODS: The NASA Smart Probe uses neural networks and data from multiple microsensors for a unique tissue signature in real time. Animal and human trials use several probe configurations: (1) 8-microsensor probe (2.5 mm in diameter) for rodent studies (normal and subcutaneous mammary tumor tissues), and (2) 21-gauge needle probe with 3 spectroscopic fibers and an impedance microelectrode for breast cancer diagnosis in humans. Multisensor data are collected in real time (update 100 times/s) using PCs. RESULTS: Human data (collected by NASA licensee BioLuminate) from 15 women undergoing breast biopsy distinguished normal tissue from both benign tumors and breast carcinoma. Tumor margins and necrosis are rapidly detected. CONCLUSION: Real-time tissue identification is achievable. Potential applications, including probes incorporating nanoelectrode arrays, are presented. Copyright 2003 S. Karger AG, Basel.

Absorption enhancement and sensing properties of Ag diamond nanoantenna arrays

NASA Astrophysics Data System (ADS)

Yuan, Yu-Yang; Yuan, Zong-Heng; Li, Xiao-Nan; Wu, Jun; Zhang, Wen-Tao; Ye, Song

2015-07-01

Noble metal nanoantenna could effectively enhance light absorption and increase detection sensitivity. In this paper, we propose a periodic Ag diamond nanoantenna array to increase the absorption of thin-film solar cells and to improve the detection sensitivity via localized surface plasmon resonance. The effect of nanoantenna arrays on the absorption enhancement is theoretically investigated using the finite difference time domain (FDTD) method with manipulating the spectral response by geometrical parameters of nanoantennas. A maximum absorption enhancement factor of 1.51 has been achieved in this study. In addition, the relation between resonant wavelength (intensity reflectivity) and refractive index is discussed in detail. When detecting the environmental index using resonant wavelengths, a maximum detection sensitivity of about 837 nm/RIU (refractive index unit) and a resolution of about 10-3 RIU can be achieved. Moreover, when using the reflectivity, the sensitivity can be as high as 0.93 AU/RIU. Furthermore, we also have theoretically studied the effectiveness of nanoantennas in distinguishing chemical reagents, solution concentrations, and solution allocation ratios by detecting refractive index. From the results presented in this paper, we conclude that this work might be useful for biosensor detection and other types of detections. Project supported by the International Scientific and Technological Cooperation Projects of Guizhou Province, China (Grant No. 20117035) and the Program for Innovative Research Team of Guilin University of Electronic Technology, China (Grant No. IRTGUET).

The Expanded Owens Valley Solar Array

NASA Astrophysics Data System (ADS)

Gary, Dale E.; Hurford, G. J.; Nita, G. M.; White, S. M.; Tun, S. D.; Fleishman, G. D.; McTiernan, J. M.

2011-05-01

The Expanded Owens Valley Solar Array (EOVSA) is now under construction near Big Pine, CA as a solar-dedicated microwave imaging array operating in the frequency range 1-18 GHz. The solar science to be addressed focuses on the 3D structure of the solar corona (magnetic field, temperature and density), on the sudden release of energy and subsequent particle acceleration, transport and heating, and on space weather phenomena. The project will support the scientific community by providing open data access and software tools for analysis of the data, to exploit synergies with on-going solar research in other wavelengths. The New Jersey Institute of Technology (NJIT) is expanding OVSA from its previous complement of 7 antennas to a total of 15 by adding 8 new antennas, and will reinvest in the existing infrastructure by replacing the existing control systems, signal transmission, and signal processing with modern, far more capable and reliable systems based on new technology developed for the Frequency Agile Solar Radiotelescope (FASR). The project will be completed in time to provide solar-dedicated observations during the upcoming solar maximum in 2013 and beyond. We provide an update on current status and our preparations for exploiting the data through modeling and data analysis tools. This research is supported by NSF grants AST-0908344, and AGS-0961867 and NASA grant NNX10AF27G to New Jersey Institute of Technology.

Proceedings of the flat-plate solar array project research forum on photovoltaic metallization systems

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

None

1983-11-15

A Photovoltaic Metallization Research Forum, under the sponsorship of the Jet Propulsion Laboratory's Flat-Plate Solar Array Project and the US Department of Energy, was held March 16-18, 1983 at Pine Mountain, Georgia. The Forum consisted of five sessions, covering (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques and (5) future metallization challenges. Twenty-three papers were presented.

Operation and performance of the EEE network array for the detection of cosmic rays

NASA Astrophysics Data System (ADS)

Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Licciulli, F.; Maggiora, A.; Maragoto Rodriguez, O.; Maron, G.; Martelli, B.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Park, W.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Visnyei, O. B.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

2017-02-01

The EEE (Extreme Energy Events) Project is an experiment for the detection of cosmic ray muons by means of a sparse array of telescopes, each made of three Multigap Resistive Plate Chambers (MRPC), distributed over all the Italian territory and at CERN. The main scientific goals of the Project are the investigation of the properties of the local muon flux, the detection of Extensive Air Showers (EAS) and the search for long-distance correlations between far telescopes. The Project is also characterized by a strong educational and outreach aspect since the telescopes are managed by teams of students and teachers who had previously constructed them at CERN. In this paper an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array, which currently consists of more than 50 telescopes, is also presented by showing the most recent physics results.

SU-F-T-559: High-Resolution Scintillating Fiber Array for In-Vivo Real-Time SRS and SBRT Patient QA

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

Knewtson, T; Pokhrel, S; University of Tennessee Health Science Center, Memphis, TN

2016-06-15

Purpose: A high-resolution scintillating fiber detector was built for in-vivo real-time patient specific quality assurance (QA). The detector is designed for stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) to monitor treatment delivery and detect real-time deviations from planned dose to increase patient safety and treatment accuracy. Methods: The detector consists of two high-density scintillating fiber arrays layered to form an X-Y grid which can be attached to the accessory tray of a medical linac for SBRT and cone SRS treatment QA. Fiber arrays consist of 128 scintillating fibers embedded within a precision-machined, high-transmission polymer substrate with 0.8mm pitch. Themore » fibers are coupled on both ends to high-sensitivity photodetectors and the output is recorded through a high-speed analog-to-digital converter to capture the linac pulse sequence as treatment delivery progresses. The detector has a software controlled 360 degree rotational system to capture angular beam projections for high-resolution beam profile reconstruction. Results: The detector was validated using SRS cone sizes from 6mm to 34mm and MLC defined field sizes from 5×5mm2 to 100×100mm2. The detector output response is linear with dose and is dose rate independent. Each field can be reconstructed accurately with a spatial resolution of 0.8mm and the current beam output is displayed every 50msec. Dosimetric errors of 1% with respect to the treatment plan can be identified and clinically significant deviations from the expected treatment can be displayed in real-time to alert the therapists. Conclusion: The high resolution detector is capable of reconstructing beam profiles in real-time with submillimeter resolution and 1% dose resolution. This system has the ability to project in-vivo both spatial and dosimetric errors during SBRT and SRS treatments when only a non-clinically significant fraction of the intended dose was delivered. The device has the potential to establish new standards for in-vivo patient specific QA.« less

Rupture imaging of the Mw 7.9 12 May 2008 Wenchuan earthquake from back projection of teleseismic P waves

USGS Publications Warehouse

Xu, Y.; Koper, K.D.; Sufri, O.; Zhu, L.; Hutko, Alexander R.

2009-01-01

[1] The Mw 7.9 Wenchuan earthquake of 12 May 2008 was the most destructive Chinese earthquake since the 1976 Tangshan event. Tens of thousands of people were killed, hundreds of thousands were injured, and millions were left homeless. Here we infer the detailed rupture process of the Wenchuan earthquake by back-projecting teleseismic P energy from several arrays of seismometers. This technique has only recently become feasible and is potentially faster than traditional finite-fault inversion of teleseismic body waves; therefore, it may reduce the notification time to emergency response agencies. Using the IRIS DMC, we collected 255 vertical component broadband P waves at 30-95?? from the epicenter. We found that at periods of 5 s and greater, nearly all of these P waves were coherent enough to be used in a global array. We applied a simple down-sampling heuristic to define a global subarray of 70 stations that reduced the asymmetry and sidelobes of the array response function (ARF). We also considered three regional subarrays of seismometers in Alaska, Australia, and Europe that had apertures less than 30?? and P waves that were coherent to periods as short as 1 s. Individual ARFs for these subarrays were skewed toward the subarrays; however, the linear sum of the regional subarray beams at 1 s produced a symmetric ARF, similar to that of the groomed global subarray at 5 s. For both configurations we obtained the same rupture direction, rupture length, and rupture time. We found that the Wenchuan earthquake had three distinct pulses of high beam power at 0, 23, and 57 s after the origin time, with the pulse at 23 s being highest, and that it ruptured unilaterally to the northeast for about 300 km and 110 s, with an average speed of 2.8 km/s. It is possible that similar results can be determined for future large dip-slip earthquakes within 20-30 min of the origin time using relatively sparse global networks of seismometers such as those the USGS uses to locate earthquakes in near-real time. Copyright 2009 by the American Geophysical Union.

An Investigation into the Poor Survival of an Endangered Coho Salmon Population

PubMed Central

Chittenden, Cedar M.; Melnychuk, Michael C.; Welch, David W.; McKinley, R. Scott

2010-01-01

To investigate reasons for the decline of an endangered population of coho salmon (O. kisutch), 190 smolts were acoustically tagged during three consecutive years and their movements and survival were estimated using the Pacific Ocean Shelf Tracking project (POST) array. Median travel times of the Thompson River coho salmon smolts to the lower Fraser River sub-array were 16, 12 and 10 days during 2004, 2005 and 2006, respectively. Few smolts were recorded on marine arrays. Freshwater survival rates of the tagged smolts during their downstream migration were 0.0–5.6% (0.0–9.0% s.e.) in 2004, 7.0% (6.2% s.e.) in 2005, and 50.9% (18.6% s.e.) in 2006. Overall smolt-to-adult return rates exhibited a similar pattern, which suggests that low freshwater survival rates of out-migrating smolts may be a primary reason for the poor conservation status of this endangered coho salmon population. PMID:20526367

Low threshold all-optical crossbar switch on GaAs-GaAlAs channel waveguide arrays

NASA Astrophysics Data System (ADS)

Jannson, Tomasz; Kostrzewski, Andrew

1994-09-01

During the Phase 2 project entitled 'Low Threshold All-Optical Crossbar Switch on GaAs - GaAlAs Channel Waveguide Array,' Physical Optics Corporation (POC) developed the basic principles for the fabrication of all-optical crossbar switches. Based on this development. POC fabricated a 2 x 2 GaAs/GaAlAs switch that changes the direction of incident light with minimum insertion loss and nonlinear distortion. This unique technology can be used in both analog and digital networks. The applications of this technology are widespread. Because the all-optical network does not have any speed limitations (RC time constant), POC's approach will be beneficial to SONET networks, phased array radar networks, very high speed oscilloscopes, all-optical networks, IR countermeasure systems, BER equipment, and the fast growing video conferencing network market. The novel all-optical crossbar switch developed in this program will solve interconnect problems. and will be a key component in the widely proposed all-optical 200 Gb/s SONET/ATM networks.

Simulation of the hybrid Tunka Advanced International Gamma-ray and Cosmic ray Astrophysics (TAIGA)

NASA Astrophysics Data System (ADS)

Kunnas, M.; Astapov, I.; Barbashina, N.; Beregnev, S.; Bogdanov, A.; Bogorodskii, D.; Boreyko, V.; Brückner, M.; Budnev, N.; Chiavassa, A.; Chvalaev, O.; Dyachok, A.; Epimakhov, S.; Eremin, T.; Gafarov, A.; Gorbunov, N.; Grebenyuk, V.; Gress, O.; Gress, T.; Grinyuk, A.; Grishin, O.; Horns, D.; Ivanova, A.; Karpov, N.; Kalmykov, N.; Kazarina, Y.; Kindin, V.; Kirichkov, N.; Kiryuhin, S.; Kokoulin, R.; Kompaniets, K.; Konstantinov, E.; Korobchenko, A.; Korosteleva, E.; Kozhin, V.; Kuzmichev, L.; Lenok, V.; Lubsandorzhiev, B.; Lubsandorzhiev, N.; Mirgazov, R.; Mirzoyan, R.; Monkhoev, R.; Nachtigall, R.; Pakhorukov, A.; Panasyuk, M.; Pankov, L.; Perevalov, A.; Petrukhin, A.; Platonov, V.; Poleschuk, V.; Popescu, M.; Popova, E.; Porelli, A.; Porokhovoy, S.; Prosin, V.; Ptuskin, V.; Romanov, V.; Rubtsov, G. I.; Müger; Rybov, E.; Samoliga, V.; Satunin, P.; Saunkin, A.; Savinov, V.; Semeney, Yu; Shaibonov (junior, B.; Silaev, A.; Silaev (junior, A.; Skurikhin, A.; Slunecka, M.; Spiering, C.; Sveshnikova, L.; Tabolenko, V.; Tkachenko, A.; Tkachev, L.; Tluczykont, M.; Veslopopov, A.; Veslopopova, E.; Voronov, D.; Wischnewski, R.; Yashin, I.; Yurin, K.; Zagorodnikov, A.; Zirakashvili, V.; Zurbanov, V.

2015-08-01

Up to several 10s of TeV, Imaging Air Cherenkov Telescopes (IACTs) have proven to be the instruments of choice for GeV/TeV gamma-ray astronomy due to their good reconstrucion quality and gamma-hadron separation power. However, sensitive observations at and above 100 TeV require very large effective areas (10 km2 and more), which is difficult and expensive to achieve. The alternative to IACTs are shower front sampling arrays (non-imaging technique or timing-arrays) with a large area and a wide field of view. Such experiments provide good core position, energy and angular resolution, but only poor gamma-hadron separation. Combining both experimental approaches, using the strengths of both techniques, could optimize the sensitivity to the highest energies. The TAIGA project plans to combine the non-imaging HiSCORE [8] array with small (∼10m2) imaging telescopes. This paper covers simulation results of this hybrid approach.

Development of a computer-assisted forensic radiographic identification method using the lateral cervical and lumbar spine.

PubMed

Derrick, Sharon M; Raxter, Michelle H; Hipp, John A; Goel, Priya; Chan, Elaine F; Love, Jennifer C; Wiersema, Jason M; Akella, N Shastry

2015-01-01

Medical examiners and coroners (ME/C) in the United States hold statutory responsibility to identify deceased individuals who fall under their jurisdiction. The computer-assisted decedent identification (CADI) project was designed to modify software used in diagnosis and treatment of spinal injuries into a mathematically validated tool for ME/C identification of fleshed decedents. CADI software analyzes the shapes of targeted vertebral bodies imaged in an array of standard radiographs and quantifies the likelihood that any two of the radiographs contain matching vertebral bodies. Six validation tests measured the repeatability, reliability, and sensitivity of the method, and the effects of age, sex, and number of radiographs in array composition. CADI returned a 92-100% success rate in identifying the true matching pair of vertebrae within arrays of five to 30 radiographs. Further development of CADI is expected to produce a novel identification method for use in ME/C offices that is reliable, timely, and cost-effective. © 2014 American Academy of Forensic Sciences.

IRIS DMC products help explore the Tohoku earthquake

NASA Astrophysics Data System (ADS)

Trabant, C.; Hutko, A. R.; Bahavar, M.; Ahern, T. K.; Benson, R. B.; Casey, R.

2011-12-01

Within two hours after the great March 11, 2011 Tohoku earthquake the IRIS DMC started publishing automated data products through its Searchable Product Depository (SPUD), which provides quick viewing of many aspects of the data and preliminary analysis of this great earthquake. These products are part of the DMC's data product development effort intended to serve many purposes: stepping-stones for future research projects, data visualizations, data characterization, research result comparisons as well as outreach material. Our current and soon-to-be-released products that allow users to explore this and other global M>6.0 events include 1) Event Plots, which are a suite of maps, record sections, regional vespagrams and P-coda stacks 2) US Array Ground Motion Visualizations that show the vertical and horizontal global seismic wavefield sweeping across US Array including minor and major arc surface waves and their polarizations 3) back-projection movies that show the time history of short-period energy from the rupture 4) R1 source-time functions that show approximate duration and source directivity and 5) aftershock sequence maps and statistics movies based on NEIC alerts that self-update every hour in the first few days following the mainshock. Higher order information for the Tohoku event that can be inferred based on our products which will be highlighted include a rupture duration of order 150 sec (P-coda stacks, back-projections, R1 STFs) that ruptured approximately 400 km along strike primarily towards the south (back-projections, R1 STFs, aftershock animation) with a very low rupture velocity (back-projections, R1 STFs). All of our event-based products are automated and consistently produced shortly after the event so that they may serve as familiar baselines for the seismology research community. More details on these and other existing products are available at: http://www.iris.edu/dms/products/

Measuring research progress in photovoltaics

NASA Technical Reports Server (NTRS)

Jackson, B.; Mcguire, P.

1986-01-01

The role and some results of the project analysis and integration function in the Flat-plate Solar Array (FSA) Project are presented. Activities included supporting the decision-making process, preparation of plans for project direction, setting goals for project activities, measuring progress within the project, and the development and maintenance of analytical models.

Mountainous Ecosystem Sensor Array (MESA): a mesh sensor network for climate change research in remote mountainous environments

NASA Astrophysics Data System (ADS)

Robinson, P. W.; Neal, D.; Frome, D.; Kavanagh, K.; Davis, A.; Gessler, P. E.; Hess, H.; Holden, Z. A.; Link, T. E.; Newingham, B. A.; Smith, A. M.

2013-12-01

Developing sensor networks robust enough to perform unattended in the world's remote regions is critical since these regions serve as important benchmarks that lack anthropogenic influence. Paradoxically, the factors that make these remote, natural sites challenging for sensor networking are often what make them indispensable for climate change research. The MESA (Mountainous Ecosystem Sensor Array) project has faced these challenges and developed a wireless mesh sensor network across a 660 m topoclimatic gradient in a wilderness area in central Idaho. This sensor array uses advances in sensing, networking, and power supply technologies to provide near real-time synchronized data covering a suite of biophysical parameters used in ecosystem process models. The 76 sensors in the network monitor atmospheric carbon dioxide concentration, humidity, air and soil temperature, soil water content, precipitation, incoming and outgoing shortwave and longwave radiation, snow depth, wind speed and direction, and leaf wetness at synchronized time intervals ranging from two minutes to two hours and spatial scales from a few meters to two kilometers. We present our novel methods of placing sensors and network nodes above, below, and throughout the forest canopy without using meteorological towers. In addition, we explain our decision to use different forms of power (wind and solar) and the equipment we use to control and integrate power harvesting. Further, we describe our use of the network to sense and quantify its own power use. Using examples of environmental data from the project, we discuss how these data may be used to increase our understanding of the effects of climate change on ecosystem processes in mountainous environments. MESA sensor locations across a 700 m topoclimatic gradient at the University of Idaho Taylor Wilderness Research Station.

A SEP Mission to Jupiter Using the Stretched Lens Array

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W.; Rodiek, Julie A.; Ferguson, Dale C.; O'Neill, Mark J.; Piszczor, Michael F.; Oleson, Steve

2008-01-01

As space exploration continues to be a primary focus of NASA, solar electric propulsion (SEP) becomes a forerunner in the mode of transportation to reach other planets in our solar system. Several critical issues emerge as potential barriers to this approach such as reducing solar array radiation damage, operating the array at high voltage (>300 V) for extended times for Hall or ion thrusters, and designing an array that will be resistant to micrometeoroid impacts and the differing environmental conditions as the vehicle travels further into space. It is also of great importance to produce an array that is light weight to preserve payload mass fraction and to do this at a cost that is lower than today's arrays. This paper will describe progress on an array that meets all these requirements and will detail its use in a solar electric mission to Jupiter. From 1998-2001, NASA flew the Deep Space 1 mission that validated the use of ion propulsion for extended space missions. This highly successful two-year mission also used a novel SCARLET solar array that concentrated sunlight eight-fold onto small area solar cells. This array performed flawlessly and within 2% of its projected performance over the entire mission. That design has evolved into the Stretched Lens Array (SLA) shown in figure 1. The primary difference between SCARLET and the SLA is that no additional glass cover is used over the silicone lens. This has led to significant mass, cost and complexity reductions. The module shown in figure 1 is the latest version of the design. This design leads to a specific power exceeding 300 W/kg at voltages exceeding 300 V. In addition, this module has been tested to voltages over 1000 V while under hypervelocity particle impact in a plasma environment with no arcing. Furthermore array segments are under test for corona breakdown that can become a critical issue for long term, high voltage missions.

Final Technical Report, City of Brockton Solar Brightfield: Deploying a Solar Array on a Brockton Brownfield

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

Ribeiro, Lori

The City of Brockton, Massachusetts sought to install New England’s largest solar array at a remediated brownfield site on Grove Street. The 425-kilowatt solar photovoltaic array – or “Brightfield” – was installed in an urban park setting along with interpretive displays to maximize the educational opportunities. The “Brightfield” project included 1,395 310-Watt solar panels connected in “strings” that span the otherwise unusable 3.7-acre site. The project demonstrated that it is both technically and economically feasible to install utility scale solar photovoltaics on a capped landfill site. The US Department of Energy conceived the Brightfields program in 2000, and Brockton’s Brightfieldmore » is the largest such installation nationwide. Brockton’s project demonstrated that while it was both technically and economically feasible to perform such a project, the implementation was extremely challenging due to the state policy barriers, difficulty obtaining grant funding, and level of sophistication required to perform the financing and secure required state approvals. This demonstration project can be used as a model for other communities that wish to implement “Brownfields to Brightfields” projects; 2) implementing utility scale solar creates economies of scale that can help to decrease costs of photovoltaics; 3) the project is an aesthetic, environmental, educational and economic asset for the City of Brockton.« less

Cost study of solar cell space power systems

NASA Technical Reports Server (NTRS)

Bernatowicz, D. T.

1972-01-01

Historical costs for solar cell space power systems were evaluated. The study covered thirteen missions that represented a broad cross section of flight projects over the past decade. Fully burdened costs in terms of 1971 dollars are presented for the system and the solar array. The costs correlate reasonably well with array area and do not increase in proportion to array area. The trends for array costs support the contention that solar cell and module standardization reduce costs.

Uncertainty Analyses for Back Projection Methods

NASA Astrophysics Data System (ADS)

Zeng, H.; Wei, S.; Wu, W.

2017-12-01

So far few comprehensive error analyses for back projection methods have been conducted, although it is evident that high frequency seismic waves can be easily affected by earthquake depth, focal mechanisms and the Earth's 3D structures. Here we perform 1D and 3D synthetic tests for two back projection methods, MUltiple SIgnal Classification (MUSIC) (Meng et al., 2011) and Compressive Sensing (CS) (Yao et al., 2011). We generate synthetics for both point sources and finite rupture sources with different depths, focal mechanisms, as well as 1D and 3D structures in the source region. The 3D synthetics are generated through a hybrid scheme of Direct Solution Method and Spectral Element Method. Then we back project the synthetic data using MUSIC and CS. The synthetic tests show that the depth phases can be back projected as artificial sources both in space and time. For instance, for a source depth of 10km, back projection gives a strong signal 8km away from the true source. Such bias increases with depth, e.g., the error of horizontal location could be larger than 20km for a depth of 40km. If the array is located around the nodal direction of direct P-waves the teleseismic P-waves are dominated by the depth phases. Therefore, back projections are actually imaging the reflection points of depth phases more than the rupture front. Besides depth phases, the strong and long lasted coda waves due to 3D effects near trench can lead to additional complexities tested here. The strength contrast of different frequency contents in the rupture models also produces some variations to the back projection results. In the synthetic tests, MUSIC and CS derive consistent results. While MUSIC is more computationally efficient, CS works better for sparse arrays. In summary, our analyses indicate that the impact of various factors mentioned above should be taken into consideration when interpreting back projection images, before we can use them to infer the earthquake rupture physics.

Enhancement of Mutual Discovery, Search, and Access of Data for Users of NASA and GEOSS-Cataloged Data Systems

NASA Technical Reports Server (NTRS)

Teng, William; Maidment, David; Rodell, Matthew; Strub, Richard; Arctur, David; Ames, Daniel; Rui, Hualan; Vollmer, Bruce; Seiler, Edward

2014-01-01

An ongoing NASA-funded Data Rods (time series) project has demonstrated the removal of a longstanding barrier to accessing NASA data (i.e., accessing archived time-step array data as point-time series) for selected variables of the North American and Global Land Data Assimilation Systems (NLDAS and GLDAS, respectively) and other NASA data sets. Data rods are pre-generated or generated on-the-fly (OTF), leveraging the NASA Simple Subset Wizard (SSW), a gateway to NASA data centers. Data rods Web services are accessible through the CUAHSI Hydrologic Information System (HIS) and the Goddard Earth Sciences Data and Information Services Center (GES DISC) but are not easily discoverable by users of other non-NASA data systems. An ongoing GEOSS Water Services project aims to develop a distributed, global registry of water data, map, and modeling services cataloged using the standards and procedures of the Open Geospatial Consortium and the World Meteorological Organization. Preliminary work has shown GEOSS can be leveraged to help provide access to data rods. A new NASA-funded project is extending this early work.

Back-Projection Imaging of extended, diffuse seismic sources in volcanic and hydrothermal systems

NASA Astrophysics Data System (ADS)

Kelly, C. L.; Lawrence, J. F.; Beroza, G. C.

2017-12-01

Volcanic and hydrothermal systems exhibit a wide range of seismicity that is directly linked to fluid and volatile activity in the subsurface and that can be indicative of imminent hazardous activity. Seismograms recorded near volcanic and hydrothermal systems typically contain "noisy" records, but in fact, these complex signals are generated by many overlapping low-magnitude displacements and pressure changes at depth. Unfortunately, excluding times of high-magnitude eruptive activity that typically occur infrequently relative to the length of a system's entire eruption cycle, these signals often have very low signal-to-noise ratios and are difficult to identify and study using established seismic analysis techniques (i.e. phase-picking, template matching). Arrays of short-period and broadband seismic sensors are proven tools for monitoring short- and long-term changes in volcanic and hydrothermal systems. Time-reversal techniques (i.e. back-projection) that are improved by additional seismic observations have been successfully applied to locating volcano-seismic sources recorded by dense sensor arrays. We present results from a new computationally efficient back-projection method that allows us to image the evolution of extended, diffuse sources of volcanic and hydrothermal seismicity. We correlate short time-window seismograms from receiver-pairs to find coherent signals and propagate them back in time to potential source locations in a 3D subsurface model. The strength of coherent seismic signal associated with any potential source-receiver-receiver geometry is equal to the correlation of the short time-windows of seismic records at appropriate time lags as determined by the velocity structure and ray paths. We stack (sum) all short time-window correlations from all receiver-pairs to determine the cumulative coherence of signals at each potential source location. Through stacking, coherent signals from extended and/or repeating sources of short-period energy radiation interfere constructively while background noise signals interfere destructively, such that the most likely source locations of the observed seismicity are illuminated. We compile results to analyze changes in the distribution and prevalence of these sources throughout a systems entire eruptive cycle.

Prototype PBO Instrumentation of CALIPSO Project Captures World-Record Lava Dome Collapse on Montserrat Volcano

NASA Astrophysics Data System (ADS)

Mattioli, Glen S.; Young, Simon R.; Voight, Barry; Sparks, R. Steven J.; Shalev, Eylon; Selwyn, Sacks; Malin, Peter; Linde, Alan; Johnston, William; Hadayat, Dannie; Elsworth, Derek; Dunkley, Peter; Herd, Richard; Neuberg, Jurgen; Norton, Gillian; Widiwijayanti, Christina

2004-08-01

This article is an update on the status of an innovative new project designed to enhance generally our understanding of andesitic volcano eruption dynamics and, specifically, the monitoring and scientific infrastructure at the active Soufriàre Hills Volcano (SHV), Montserrat. The project has been designated as the Caribbean Andesite Lava Island Precision Seismo-geodetic Observatory, known as CALIPSO. Its purpose is to investigate the dynamics of the entire SHV magmatic system using an integrated array of specialized instruments in four strategically located ~200-m-deep boreholes in concert with several shallower holes and surface sites. The project is unique, as it represents the first, and only, such borehole volcano-monitoring array deployed at an andesitic stratovolcano. CALIPSO may be considered as a prototype for planned Plate Boundary Observatory (PBO) installations at several volcanic targets in the western United States. Scientific objectives of the EarthScope Integrated Science Plan (ES-ISP) relevant to magmatic systems are to investigate (1) melt generation in the mantle; (2) melt migration from the mantle to and through the crust to the surface; (3) melt residence times at various deep reservoirs; and (4) delineation of characteristic patterns of surface deformation and seismicity, which may prove useful in eruption forecasting. The CALIPSO project shares most of the same scientific goals and has, moreover, the benefit of a rich existing geophysical context in its deployment at SHV. Our experience during instrument design, planning, drilling and installation, systems integration, and early operation of CALIPSO, moreover, may prove valuable to EarthScope and PBO managers.

An Active K-Band Receive Slot Array for Mobile Satellite Communications

NASA Technical Reports Server (NTRS)

Tulintseff, A. N.; Lee, K. A.; Sukamto, L. M.; Chew, W.

1994-01-01

An active receive slot array has been developed for operation in the downlink frequency band, 19.914-20.064 GHz, of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project.

Velocity Model Using the Large-N Seismic Array from the Source Physics Experiment (SPE)

NASA Astrophysics Data System (ADS)

Chen, T.; Snelson, C. M.

2016-12-01

The Source Physics Experiment (SPE) is a multi-institutional, multi-disciplinary project that consists of a series of chemical explosions conducted at the Nevada National Security Site (NNSS). The goal of SPE is to understand the complicated effect of geological structures on seismic wave propagation and source energy partitioning, develop and validate physics-based modeling, and ultimately better monitor low-yield nuclear explosions. A Large-N seismic array was deployed at the SPE site to image the full 3D wavefield from the most recent SPE-5 explosion on April 26, 2016. The Large-N seismic array consists of 996 geophones (half three-component and half vertical-component sensors), and operated for one month, recording the SPE-5 shot, ambient noise, and additional controlled-sources (a large hammer). This study uses Large-N array recordings of the SPE-5 chemical explosion to develop high resolution images of local geologic structures. We analyze different phases of recorded seismic data and construct a velocity model based on arrival times. The results of this study will be incorporated into the large modeling and simulation efforts as ground-truth further validating the models.

Mir Cooperative Solar Array

NASA Technical Reports Server (NTRS)

Skor, Mike; Hoffman, Dave J.

1997-01-01

The Mir Cooperative Solar Array (MCSA), produced jointly by the United States and Russia, was deployed on the Mir Russian space station on May 25, 1996. The MCSA is a photovoltaic electrical power system that can generate up to 6 kW. The power from the MCSA is needed to extend Mir's lifetime and to support experiments conducted there by visiting U.S. astronauts. The MCSA was brought to Mir via the Space Shuttle Atlantis on the STS-74 mission, launched November 12, 1995. This cooperative venture combined the best technology of both countries: the United States provided high-efficiency, lightweight photovoltaic panel modules, whereas Russia provided the array structure and deployment mechanism. Technology developed in the Space Station Freedom Program, and now being used in the International Space Station, was used to develop MCSA's photovoltaic panel. Performance data obtained from MCSA operation on Mir will help engineers better understand the performance of the photovoltaic panel modules in orbit. This information will be used to more accurately predict the performance of the International Space Station solar arrays. Managed by the NASA Lewis Research Center for NASA's International Space Station Program Office in Houston, Texas, the MCSA Project was completed on time and under budget despite a very aggressive schedule.

Technology Development for AGIS (Advanced Gamma-ray Imaging System).

NASA Astrophysics Data System (ADS)

Krennrich, Frank

2008-04-01

Next-generation arrays of atmospheric Cherenkov telescopes are at the conceptual planning stage and each could consist of on the order of 100 telescopes. The two currently-discussed projects AGIS in the US and CTA in Europe, have the potential to achieve an order of magnitude better sensitivity for Very High Energy (VHE) gamma-ray observations over state-to-the-art observatories. These projects require a substantial increase in scale from existing 4-telescope arrays such as VERITAS and HESS. The optimization of a large array requires exploring cost reduction and research and development for the individual elements while maximizing their performance as an array. In this context, the technology development program for AGIS will be discussed. This includes developing new optical designs, evaluating new types of photodetectors, developing fast trigger systems, integrating fast digitizers into highly-pixilated cameras, and reliability engineering of the individual components.

Solar Panel Integration as an Alternate Power Source on Centaur 2 (SPIAPS)

NASA Technical Reports Server (NTRS)

Gebara, Christine A.; Schuetze, Nich A.; Knochel, Aviana M.; Magruder, Darby F.

2011-01-01

The dream of exploration has inspired thousands throughout time. Space exploration, in particular, has taken the past century by storm and caused a great advance in technology. In this project, a retractable solar panel array will be developed for use on the Centaur 2 Rover. Energy generated by the solar panels will go to power the Centaur 2 Robot (C2) or Regolith & Environment Science & Oxygen & Lunar Volatile Extraction (RESOLVE) payload, an in-situ resource utilization project. Such payload is designed to drill into lunar and Martian terrain as well as be able to conduct other geological testing; RESOLVE is slated for testing in 2012. Ultimately, this project will fit into NASA s larger goal of deep space exploration as well as long term presence outside Earth s orbit.

The application of Fresnel zone plate based projection in optofluidic microscopy.

PubMed

Wu, Jigang; Cui, Xiquan; Lee, Lap Man; Yang, Changhuei

2008-09-29

Optofluidic microscopy (OFM) is a novel technique for low-cost, high-resolution on-chip microscopy imaging. In this paper we report the use of the Fresnel zone plate (FZP) based projection in OFM as a cost-effective and compact means for projecting the transmission through an OFM's aperture array onto a sensor grid. We demonstrate this approach by employing a FZP (diameter = 255 microm, focal length = 800 microm) that has been patterned onto a glass slide to project the transmission from an array of apertures (diameter = 1 microm, separation = 10 microm) onto a CMOS sensor. We are able to resolve the contributions from 44 apertures on the sensor under the illumination from a HeNe laser (wavelength = 633 nm). The imaging quality of the FZP determines the effective field-of-view (related to the number of resolvable transmissions from apertures) but not the image resolution of such an OFM system--a key distinction from conventional microscope systems. We demonstrate the capability of the integrated system by flowing the protist Euglena gracilis across the aperture array microfluidically and performing OFM imaging of the samples.

Using Large-Scale Roughness Elements to Control Sand and Dust Flux at the Keeler Dunes, Keeler, CA

NASA Astrophysics Data System (ADS)

Gillies, John; McCarley-Holder, Grace

2014-05-01

Controlling dust emission from areas that subsequently degrade air quality and threaten human and animal health and reduce the quality of life for people residing in proximity to such sources is necessary, but also challenging. Recent research has indicated that arrays of large roughness elements (height >0.3 m) can be used effectively to modulate sand transport and the associated dust emissions. Prediction of the rate of sand flux reduction as a function of downwind distance upon entering an array of roughness elements, and the equilibrium flux reduction in the interior of the array is possible using the known geometric properties of the roughness elements, their number, and published relationships. Air quality in the town of Keeler, CA (36 deg 29' 17.92" N, 117 deg 52' 24.62" W) is degraded by levels of particulate matter <10 µm aerodynamic diameter (PM10) during periods of elevated wind speeds due to sand transport and dust emissions in the nearby Keeler Dunes. A demonstration project was designed to evaluate the effectiveness of an array of roughness elements composed of solid elements and managed vegetation to meet sand and dust flux reduction criteria. This project has two major goals: 1) to demonstrate that solid roughness elements placed on areas of the Keeler Dunes immediately arrest sand movement to specified levels (target of 85% reduction), and 2) to assess whether native plant species, planted in the sheltered area of the solid roughness elements can effectively thrive and subsequently replace the solid roughness to achieve the desired sand flux reduction control efficiency. This poster describes the results related mostly to objective one, as considerable time has to pass before sufficient data will be obtained to evaluate the success of the planted and managed vegetation to achieve a control level provided by the solid element roughness array.

The ASTRI/CTA mini-array software system

NASA Astrophysics Data System (ADS)

Tosti, Gino; Schwarz, Joseph; Antonelli, Lucio Angelo; Trifoglio, Massimo; Catalano, Osvaldo; Maccarone, Maria Concetta; Leto, Giuseppe; Gianotti, Fulvio; Canestrari, Rodolfo; Giro, Enrico; Fiorini, Mauro; La Palombara, Nicola; Pareschi, Giovanni; Stringhetti, Luca; Vercellone, Stefano; Conforti, Vito; Tanci, Claudio; Bruno, Pietro; Grillo, Alessandro; Testa, Vincenzo; di Paola, Andrea; Gallozzi, Stefano

2014-07-01

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project financed by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. The main goals of the ASTRI project are the realization of an end-to-end prototype of a Small Size Telescope (SST) for the Cherenkov Telescope Array (CTA) in a dual- mirror configuration (SST-2M) and, subsequently, of a mini-array comprising seven SST-2M telescopes. The mini-array will be placed at the final CTA Southern Site, which will be part of the CTA seed array, around which the whole CTA observatory will be developed. The Mini-Array Software System (MASS) will provide a comprehensive set of tools to prepare an observing proposal, to perform the observations specified therein (monitoring and controlling all the hardware components of each telescope), to analyze the acquired data online and to store/retrieve all the data products to/from the archive. Here we present the main features of the MASS and its first version, to be tested on the ASTRI SST-2M prototype that will be installed at the INAF observing station located at Serra La Nave on Mount Etna in Sicily.

Projection-based estimation and nonuniformity correction of sensitivity profiles in phased-array surface coils.

PubMed

Yun, Sungdae; Kyriakos, Walid E; Chung, Jun-Young; Han, Yeji; Yoo, Seung-Schik; Park, Hyunwook

2007-03-01

To develop a novel approach for calculating the accurate sensitivity profiles of phased-array coils, resulting in correction of nonuniform intensity in parallel MRI. The proposed intensity-correction method estimates the accurate sensitivity profile of each channel of the phased-array coil. The sensitivity profile is estimated by fitting a nonlinear curve to every projection view through the imaged object. The nonlinear curve-fitting efficiently obtains the low-frequency sensitivity profile by eliminating the high-frequency image contents. Filtered back-projection (FBP) is then used to compute the estimates of the sensitivity profile of each channel. The method was applied to both phantom and brain images acquired from the phased-array coil. Intensity-corrected images from the proposed method had more uniform intensity than those obtained by the commonly used sum-of-squares (SOS) approach. With the use of the proposed correction method, the intensity variation was reduced to 6.1% from 13.1% of the SOS. When the proposed approach was applied to the computation of the sensitivity maps during sensitivity encoding (SENSE) reconstruction, it outperformed the SOS approach in terms of the reconstructed image uniformity. The proposed method is more effective at correcting the intensity nonuniformity of phased-array surface-coil images than the conventional SOS method. In addition, the method was shown to be resilient to noise and was successfully applied for image reconstruction in parallel imaging.

MODIS Validation, Data Merger and Other Activities Accomplished by the SIMBIOS Project: 2002-2003

NASA Technical Reports Server (NTRS)

Fargion, Giulietta S.; McClain, Charles R.

2003-01-01

The purpose of this technical report is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities, satellite data processing, and data product validation. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of validating and combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report focuses on the SIMBIOS Project s efforts in support of the Moderate-Resolution Imaging Spectroradiometer (MODIS) on the Earth Observing System (EOS) Terra platform (similar evaluations of MODIS/Aqua are underway). This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational project.

MARE-l in Milan: Status and Perspectives

NASA Technical Reports Server (NTRS)

Ferri, E.; Arnaboldi, C.; Ceruti, G.; Faverzani, M.; Gatti, C.; Giachero, A.; Gotti, C.; Kilbourne, C.; Kraft-Bermuth, S.; Nucciotti, A.;

MCT Detectors and ROICS for Various Format MWIR and LWIR Arrays

DTIC Science & Technology

2009-10-01

ABSTRACT Silicon ROICs for MCT LWIR (4x288, 6x576) and MWIR (128x128) diode matrix arrays were designed, manufactured and tested. MCT layers...of polysilicon and two metallization levels. MCT Detectors and ROICs for Various Format MWIR and LWIR Arrays RTO-MP-SET-151 7 - 1...Format MWIR and LWIR Arrays 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f

Design and Flood Control Assessment of 5MWp Fishing and Photovoltaic Power Project in Xinghua City

NASA Astrophysics Data System (ADS)

Guo, Liuchao; Hu, Xiaodong; Su, Yuyan; Wu, Peipei; Weng, Songgan

2017-12-01

In order to reduce coal consumption in Jiangsu Province and develop new energy sources, considering on the distribution of geology, solar energy resources, traffic and grid connection in Xinghua City, the aim is to determine the configuration of photovoltaic modules and photovoltaic array tracking mode, design photovoltaic array and layout scheme. But the project is a wading project, it is built in Dong Tan Lake polder I115, it needs scientific and reasonable evaluation to the effect of Dong Tan Lake’s flood storage and discharge. The results can provide guidance for similar engineering’s design.

SiPM detectors for the ASTRI project in the framework of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Billotta, Sergio; Marano, Davide; Bonanno, Giovanni; Belluso, Massimiliano; Grillo, Alessandro; Garozzo, Salvatore; Romeo, Giuseppe; Timpanaro, Maria Cristina; Maccarone, Maria Concetta C.; Catalano, Osvaldo; La Rosa, Giovanni; Sottile, Giuseppe; Impiombato, Domenico; Gargano, Carmelo; Giarrusso, Salavtore

2014-07-01

The Cherenkov Telescope Array (CTA) is a worldwide new generation project aimed at realizing an array of a hundred ground based gamma-ray telescopes. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is the Italian project whose primary target is the development of an end-to-end prototype, named ASTRI SST-2M, of the CTA small size class of telescopes devoted to investigation of the highest energy region, from 1 to 100 TeV. Next target is the implementation of an ASTRI/CTA mini-array based on seven identical telescopes. Silicon Photo-Multipliers (SiPMs) are the semiconductor photosensor devices designated to constitute the camera detection system at the focal plane of the ASTRI telescopes. SiPM photosensors are suitable for the detection of the Cherenkov flashes, since they are very fast and sensitive to the light in the 300-700nm wavelength spectrum. Their drawbacks compared to the traditional photomultiplier tubes are high dark count rates, after-pulsing and optical cross-talk contributions, and intrinsic gains strongly dependent on temperature. Nonetheless, for a single pixel, the dark count rate is well below the Night Sky Background, the effects of cross-talk and afterpulses are typically lower than 20%, and the gain can be kept stable against temperature variations by means of adequate bias voltage compensation strategies. This work presents and discusses some experimental results from a large set of measurements performed on the SiPM sensors to be used for the ASTRI SST-2M prototype camera and on recently developed detectors demonstrating outstanding performance for the future evolution of the project in the ASTRI/CTA mini-array.

Simulation based evaluation of the designs of the Advanced Gamma-ray Imageing System (AGIS)

NASA Astrophysics Data System (ADS)

Bugaev, Slava; Buckley, James; Digel, Seth; Funk, Stephen; Konopelko, Alex; Krawczynski, Henric; Lebohec, Steohan; Maier, Gernot; Vassiliev, Vladimir

2009-05-01

The AGIS project under design study, is a large array of imaging atmospheric Cherenkov telescopes for gamma-rays astronomy between 40GeV and 100 TeV. In this paper we present the ongoing simulation effort to model the considered design approaches as a function of the main parameters such as array geometry, telescope optics and camera design in such a way the gamma ray observation capabilities can be optimized against the overall project cost.

Fiber Laser Arrays

DTIC Science & Technology

2006-05-03

AFRL-DE-PS- AFRL-DE-PS- TR-2006-1059 TR-2006-1059 FIBER LASER ARRAYS Thomas B. Simpson L-3 Communications-Jaycor 3394...LEANNE J HENRY, Lt Col, USAF L. BRUCE SIMPSON, SES Chief, High Power Solid State Laser Branch Director, Directed Energy Directorate...SUBTITLE Fiber Laser Arrays 5c. PROGRAM ELEMENT NUMBER 62605F 5d. PROJECT NUMBER 4866 5e. TASK NUMBER LR 6. AUTHOR(S) Thomas B. Simpson

The local nanohertz gravitational-wave landscape from supermassive black hole binaries

NASA Astrophysics Data System (ADS)

Mingarelli, Chiara M. F.; Lazio, T. Joseph W.; Sesana, Alberto; Greene, Jenny E.; Ellis, Justin A.; Ma, Chung-Pei; Croft, Steve; Burke-Spolaor, Sarah; Taylor, Stephen R.

2017-12-01

Supermassive black hole binary systems form in galaxy mergers and reside in galactic nuclei with large and poorly constrained concentrations of gas and stars. These systems emit nanohertz gravitational waves that will be detectable by pulsar timing arrays. Here we estimate the properties of the local nanohertz gravitational-wave landscape that includes individual supermassive black hole binaries emitting continuous gravitational waves and the gravitational-wave background that they generate. Using the 2 Micron All-Sky Survey, together with galaxy merger rates from the Illustris simulation project, we find that there are on average 91 ± 7 continuous nanohertz gravitational-wave sources, and 7 ± 2 binaries that will never merge, within 225 Mpc. These local unresolved gravitational-wave sources can generate a departure from an isotropic gravitational-wave background at a level of about 20 per cent, and if the cosmic gravitational-wave background can be successfully isolated, gravitational waves from at least one local supermassive black hole binary could be detected in 10 years with pulsar timing arrays.

Gas Ring-Imagining Cherenkov (GRINCH) Detector for the Super BigBite Spectrometer at Jefferson Lab

NASA Astrophysics Data System (ADS)

Averett, Todd; Wojtsekhowski, Bogdan; Amidouch, Abdellah; Danagoulian, Samuel; Niculescu, Gabriel; Niculescu, Ioana; Jefferson Lab SBS Collaboration Collaboration

2017-01-01

A new gas Cherenkov detector is under construction for the upcoming SuperBigBite spectrometer research program in Hall A at Jefferson Lab. The existing BigBite spectrometer is being upgraded to handle expected increases in event rate and background rate due to the increased luminosity required for the experimental program. The detector will primarily be used to separate good electron events from significant pion and electromagnetic contamination. In contrast to typical gas Cherenkov detectors that use large-diameter photomultiplier tubes and charge integrating ADCs, this detector uses an array of 510 small-diameter tubes that are more than 25x less sensitive to background. Cherenkov radiation clusters will be identified in this array using fast TDCs and a narrow timing window relative to typical ADC gates. In addition, a new FPGA-based DAQ system is being tested to provide a PID trigger using real-time cluster finding. Details of the detector and current status of the project will be presented.

High-resolution shallow structure revealed with ambient noise tomography on a dense array

NASA Astrophysics Data System (ADS)

Zeng, X.; Thurber, C. H.; Luo, Y.; Matzel, E.; Team, P.

2016-12-01

A dense seismic array was deployed by the PoroTomo research team at Brady Hot Springs, Nevada in March 2016. The array consisted of 238 short-period three-component geophones (5-Hz corner frequency) with about 60 m spacing. Over the 15 day deployment, the array recorded over 6,000 active source signals (vibroseis sweeps) and ambient noise that was dominated by traffic noise.We adopted the one-bit method to better reduce the effect of the active source. Spectral whitening was performed between 0.5 and 2 Hz. The continuous record was chopped into 1 minute segments. The 1-minute cross-correlation functions were initially stacked linearly, and then the phase-weighted stacking method was applied to improve signal quality. More than two million noise correlation functions (NCFs) have been obtained.The Rayleigh wave group velocity was measured on the symmetric component of the NCFs with the frequency-time analysis method. The average group velocity is about 400 m/s at 4 Hz, which is consistent with preliminary active source result. To avoid mis-picking possible precursors, the arrival time was picked at the peak in a two-second time window predicted with the average group velocity of the fundamental mode. The quality of the arrival measurements is defined by the signal-to-noise ratio. We were able to pick reliable arrivals at about 35% of the station-pairs. Since the straight-ray assumption may not be valid in a strongly heterogeneous medium, the wave path was traced with a finite difference scheme and the LSQR method was utilized to invert group velocity. The heterogeneous features of the group velocity map are consistent with a local geologic map. The PoroTomo project is funded by a grant from the U.S. Department of Energy.

Project Cyclops: a Design Study of a System for Detecting Extraterrestrial Intelligent Life

NASA Technical Reports Server (NTRS)

1972-01-01

The requirements in hardware, manpower, time and funding to conduct a realistic effort aimed at detecting the existence of extraterrestrial intelligent life are examined. The methods used are limited to present or near term future state-of-the-art techniques. Subjects discussed include: (1) possible methods of contact, (2) communication by electromagnetic waves, (3) antenna array and system facilities, (4) antenna elements, (5) signal processing, (6) search strategy, and (7) radio and radar astronomy.

Source localization of non-stationary acoustic data using time-frequency analysis

NASA Astrophysics Data System (ADS)

Stoughton, Jack; Edmonson, William

2005-04-01

An improvement in temporal locality of the generalized cross-correlation (GCC) for angle of arrival (AOA) estimation can be achieved by employing 2-D cross-correlation of infrasonic sensor data transformed to its time-frequency (TF) representation. Intermediate to the AOA evaluation is the time delay between pairs of sensors. The signal class of interest includes far field sources which are partially coherent across the array, nonstationary, and wideband. In addition, signals can occur as multiple short bursts, for which TF representations may be more appropriate for time delay estimation. The GCC tends to smooth out such temporal energy bursts. Simulation and experimental results will demonstrate the improvement in using a TF-based GCC, using the Cohen class, over the classic GCC method. Comparative demonstration of the methods will be performed on data captured on an infrasonic sensor array located at NASA Langley Research Center (LaRC). The infrasonic data sources include Delta IV and Space Shuttle launches from Kennedy Space Center which belong to the stated signal class. Of interest is to apply this method to the AOA estimation of atmospheric turbulence. [Work supported by NASA LaRC Creativity and Innovation project: Infrasonic Detection of Clear Air Turbulence and Severe Storms.

Historical Evidence of Importance to the Industrialization of Flat-plate Silicon Photovoltaic Systems, Volume 2

NASA Technical Reports Server (NTRS)

Smith, J. L.; Gates, W. R.; Lee, T.

1978-01-01

Problems which may arise as the low cost silicon solar array (LSSA) project attempts to industrialize the production technologies are defined. The charge to insure an annual production capability of 500 MW peak for the photovoltaic supply industry by 1986 was critically examined, and focused on one of the motivations behind this goal-concern over the timely development of industrial capacity to supply anticipated demand. Conclusions from the analysis are utilized in a discussion of LSSA's industrialization plans, particularly the plans for pilot, demonstration and commercial scale production plants. Specific recommendations for the implementation of an industrialization task and the disposition of the project quantity goal were derived.

Analysis and evaluation in the production process and equipment area of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Goldman, H.; Wolf, M.

1979-01-01

The energy consumed in manufacturing silicon solar cell modules was calculated for the current process, as well as for 1982 and 1986 projected processes. In addition, energy payback times for the above three sequences are shown. The module manufacturing energy was partitioned two ways. In one way, the silicon reduction, silicon purification, sheet formation, cell fabrication, and encapsulation energies were found. In addition, the facility, equipment, processing material and direct material lost-in-process energies were appropriated in junction formation processes and full module manufacturing sequences. A brief methodology accounting for the energy of silicon wafers lost-in-processing during cell manufacturing is described.

National Academy of Sciences Recommends Continued Support of ALMA Project

NASA Astrophysics Data System (ADS)

2000-05-01

A distinguished panel of scientists today announced their support for the continued funding of the Atacama Large Millimeter Array (ALMA) Project at a press conference given by the National Academy of Sciences. The ALMA Project is an international partnership between U.S. and European astronomy organizations to build a complete imaging telescope that will produce astronomical images at millimeter and submillimeter wavelengths. The U.S. partner is the National Science Foundation, through Associated Universities, Inc., (AUI), led by Dr. Riccardo Giacconi, and the National Radio Astronomy Observatory (NRAO). "We are delighted at this show of continued support from our peers in the scientific community," said Dr. Robert Brown, ALMA U.S. Project Director and Deputy Director of NRAO. "The endorsement adds momentum to the recent strides we've made toward the building of this important telescope." In 1998, the National Research Council, the working arm of the National Academy of Sciences, charged the Astronomy and Astrophysics Survey Committee to "survey the field of space- and ground-based astronomy and astrophysics" and to "recommend priorities for the most important new initiatives of the decade 2000-2010." In a report released today, the committee wrote that it "re-affirms the recommendations of the 1991 Astronomy and Astrophysics Survey Committee by endorsing the completion of . . . the Millimeter Array (MMA, now part of the Atacama Large Millimeter Array)." In the 1991 report "The Decade of Discovery," a previous committee chose the Millimeter Array as one of the most important projects of the decade 1990-2000. Early last year, the National Science Foundation signed a Memorandum of Understanding with a consortium of European organizations that effectively merged the MMA Project with the European Large Southern Array project. The combined project was christened the Atacama Large Millimeter Array. ALMA, expected to consist of 64 antennas with 12-meter diameter dishes, will be built at a high-altitude, extremely dry mountain site in Chile's Atacama desert. The array is scheduled to be completed sometime in this decade. Millimeter-wave astronomy studies the universe in the spectral region where most of its energy lies, between the long-wavelength radio waves and the shorter-wavelength infrared waves. In this realm, ALMA will study the structure of the early universe and the evolution of galaxies; gather crucial data on the formation of stars, protoplanetary disks, and planets; and provide new insights on the familiar objects of our own solar system. "Most of the photons in the Universe lie in the millimeter wavelength regime; among existing or planned instruments only ALMA can image the sources of these photons with the crispness required to understand the events of galaxy, star and planet formation which launched them into space," said NRAO's Dr. Alwyn Wootten, U.S. ALMA Project Scientist. ALMA is an international partnership between the United States (National Science Foundation) and Europe. European participants include the European Southern Observatory, the Centre National de la Recherche Scientifique (France), the Max-Planck Gesellschaft (Germany), the Netherlands Foundation for Research in Astronomy, the United Kingdom Particle Physics and Astronomy Research Council, the Oficina de Ciencia Y Tecnologia/Instituto Geografico Nacional (Spain), and the Swedish Natural Science Research Council. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

SiO maser emission as a density tracer of circumstellar envelopes

NASA Astrophysics Data System (ADS)

Stroh, Michael; Pihlstrom, Ylva; Sjouwerman, Lorant

2018-06-01

The circumstellar envelopes (CSEs) of evolved stars offer a method to construct a sample of point-masses along the full Galactic plane, which can be used to test models of the gravitational potential. In the CSEs of red giants, SiO maser emission is frequently observed at 43 and 86 GHz, providing line-of-sight velocities. The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by observing 43 GHz SiO at the Very Large Array and 86 GHz SiO at the Atacama Large Millimeter/submillimeter Array, with an expected final sample of about 20,000 line-of-sight velocities and positions. We observed the 43 GHz and 86 GHz transitions near-simultaneously in a subsample of the sources using the Australia Telescope Compact Array and found that on average the 43 GHz v=1 line is 1.3 times stronger than the 86 GHz v=1 line. The presence of a detectable 43 GHz v=3 line alters the statistics, consistent with the SiO masers displaying 43 GHz v=3 emission arising in a denser regime in the circumstellar shell compared to those without. Comparing our results with radiative models implies that the 43 GHz v=3 line is a tracer of density variations caused by stellar pulsations. We will discuss these results in the context of the BAaDE project.

Progressing Deployment of Solar Photovoltaic Installations in the United States

NASA Astrophysics Data System (ADS)

Kwan, Calvin Lee

2011-07-01

This dissertation evaluates the likelihood of solar PV playing a larger role in national and state level renewable energy portfolios. I examine the feasibility of large-scale solar PV arrays on college campuses, the financials associated with large-scale solar PV arrays and finally, the influence of environmental, economic, social and political variables on the distribution of residential solar PV arrays in the United States. Chapter two investigates the challenges and feasibility of college campuses adopting a net-zero energy policy. Using energy consumption data, local solar insolation data and projected campus growth, I present a method to identify the minimum sized solar PV array that is required for the City College campus of the Los Angeles Community College District to achieve net-zero energy status. I document how current energy demand can be reduced using strategic demand side management, with remaining energy demand being met using a solar PV array. Chapter three focuses on the financial feasibility of large-scale solar PV arrays, using the proposed City College campus array as an example. I document that even after demand side energy management initiatives and financial incentives, large-scale solar PV arrays continue to have ROIs greater than 25 years. I find that traditional financial evaluation methods are not suitable for environmental projects such as solar PV installations as externalities are not taken into account and therefore calls for development of alternative financial valuation methods. Chapter four investigates the influence of environmental, social, economic and political variables on the distribution of residential solar PV arrays across the United States using ZIP code level data from the 2000 US Census. Using data from the National Renewable Energy Laboratory's Open PV project, I document where residential solar PVs are currently located. A zero-inflated negative binomial model was run to evaluate the influence of selected variables. Using the same model, predicted residential solar PV shares were generated and illustrated using GIS software. The results of this model indicate that solar insolation, state energy deregulation and cost of electricity are statistically significant factors positively correlated with the adoption of residential solar PV arrays. With this information, policymakers at the towns and cities level can establish effective solar PV promoting policies and regulations for their respective locations.

A Unique test for Hubble's new Solar Arrays

NASA Astrophysics Data System (ADS)

2000-10-01

In mid-October, a team from the European Space Agency (ESA) and NASA will perform a difficult, never-before-done test on one of the Hubble Space Telescope's new solar array panels. Two of these panels, or arrays, will be installed by astronauts in November 2001, when the Space Shuttle Columbia visits Hubble on a routine service mission. The test will ensure that the new arrays are solid and vibration free before they are installed on orbit. The test will be conducted at ESA's European Space Research and Technology Center (ESTEC) in Noordwijk, The Netherlands. Because of the array's size, the facility's special features, and ESA's longstanding experience with Hubble's solar arrays, ESTEC is the only place in the world the test can be performed. This test is the latest chapter in a longstanding partnership between ESA and NASA on the Hubble Space Telescope. The Large Space Simulator at ESTEC, ESA's world-class test facility, features a huge vacuum chamber containing a bank of extremely bright lights that simulate the Sun's intensity - including sunrise and sunset. By exposing the solar wing to the light and temperature extremes of Hubble's orbit, engineers can verify how the new set of arrays will act in space. Hubble orbits the Earth once every 90 minutes. During each orbit, the telescope experiences 45 minutes of searing sunlight and 45 minutes of frigid darkness. This test will detect any tiny vibrations, or jitters, caused by these dramatic, repeated changes. Even a small amount of jitter can affect Hubble's sensitive instruments and interfere with observations. Hubble's first set of solar arrays experienced mild jitter and was replaced in 1993 with a much more stable pair. Since that time, advances in solar cell technology have led to the development of even more efficient arrays. In 2001, NASA will take advantage of these improvements, by fitting Hubble with a third-generation set of arrays. Though smaller, this new set generates more power than the previous pairs. The arrays use high efficiency solar cells and an advanced structural system to support the solar panels. Unlike the earlier sets, which roll up like window shades, the new arrays are rigid. ESA provided Hubble's first two sets of solar arrays, and built and tested the motors and electronics of the new set provided by NASA Goddard Space Flight Center. Now, this NASA/ESA test has benefits that extend beyond Hubble to the world-wide aerospace community. It will greatly expand basic knowledge of the jitter phenomenon. Engineers across the globe can apply these findings to other spacecraft that are subjected to regular, dramatic changes in sunlight and temperature. Note to editors The Hubble Project The Hubble Space Telescope is a project of international co-operation between the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The partnership agreement between ESA and NASA was signed on 7 October 1977. ESA has provided two pairs of solar panels and one of Hubble's scientific instruments (the Faint Object Camera), as well as a number of other components and supports NASA during routine Servicing Missions to the telescope. In addition, 15 European scientists are working at the Space Telescope Science Institute in Baltimore (STScI), which is responsible for the scientific operation of the Hubble Observatory and is managed by the Association of Universities for Research in Astronomy (AURA) for NASA. In return, European astronomers have guaranteed access to 15% of Hubble's observing time. The Space Telescope European Coordinating Facility (ST-ECF) hosted at the European Southern Observatory (ESO) in Garching bei München, Germany, supports European Hubble users. ESA and ESO jointly operate the ST-ECF.

Acoustic Vector-Sensor Array Processing

DTIC Science & Technology

2010-06-01

NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS( ES ) Massachusetts Institute...ADDRESS( ES ) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public...section shows, vector-sensor arrays are more versatile than arrays of only pressure-sensors. Exploiting this versatility raises a number of ques

Multiple-Array Detection, Association and Location of Infrasound and Seismo-Acoustic Events - Utilization of Ground Truth Information

DTIC Science & Technology

2010-09-01

MULTIPLE-ARRAY DETECTION, ASSOCIATION AND LOCATION OF INFRASOUND AND SEISMO-ACOUSTIC EVENTS – UTILIZATION OF GROUND TRUTH INFORMATION Stephen J...and infrasound data from seismo-acoustic arrays and apply the methodology to regional networks for validation with ground truth information. In the...initial year of the project automated techniques for detecting, associating and locating infrasound signals were developed. Recently, the location

Method and apparatus for synthesis of arrays of DNA probes

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

Cerrina, Francesco; Sussman, Michael R.; Blattner, Frederick R.

The synthesis of arrays of DNA probes sequences, polypeptides, and the like is carried out using a patterning process on an active surface of a substrate. An image is projected onto the active surface of the substrate utilizing an image former that includes a light source that provides light to a micromirror device comprising an array of electronically addressable micromirrors, each of which can be selectively tilted between one of at least two positions. Projection optics receives the light reflected from the micromirrors along an optical axis and precisely images the micromirrors onto the active surface of the substrate, whichmore » may be used to activate the surface of the substrate. The first level of bases may then be applied to the substrate, followed by development steps, and subsequent exposure of the substrate utilizing a different pattern of micromirrors, with further repeats until the elements of a two dimensional array on the substrate surface have an appropriate base bound thereto. The micromirror array can be controlled in conjunction with a DNA synthesizer supplying appropriate reagents to a flow cell containing the active substrate to control the sequencing of images presented by the micromirror array in coordination of the reagents provided to the substrate.« less

Reduction of solar vector magnetograph data using a microMSP array processor

NASA Technical Reports Server (NTRS)

Kineke, Jack

1990-01-01

The processing of raw data obtained by the solar vector magnetograph at NASA-Marshall requires extensive arithmetic operations on large arrays of real numbers. The objectives of this summer faculty fellowship study are to: (1) learn the programming language of the MicroMSP Array Processor and adapt some existing data reduction routines to exploit its capabilities; and (2) identify other applications and/or existing programs which lend themselves to array processor utilization which can be developed by undergraduate student programmers under the provisions of project JOVE.

Cost study of solar cell space power systems.

NASA Technical Reports Server (NTRS)

Bernatowicz, D. T.

1972-01-01

A study of historical costs for solar cell space power systems was made by a NASA ad hoc study group. The study covered thirteen missions that represented a broad cross-section of flight projects over the past decade. Fully burdened costs in terms of 1971 dollars are presented for the system and the solar array. The costs correlate reasonably well with array area and do not increase in proportion to array area. The trends for array costs support the contention that solar cell and module standardization would reduce costs.

Low-cost solar array project and Proceedings of the 14th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1980-01-01

Activities are reported on the following areas: project analysis and integration; technology development in silicon material, large area sheet silicon, and encapsulation; production process and equipment development; and engineering and operations, and the steps taken to integrate these efforts. Visual materials presented at the project Integration Meeting are included.

Flat-plate solar array project. Volume 8: Project analysis and integration

NASA Technical Reports Server (NTRS)

Mcguire, P.; Henry, P.

1986-01-01

Project Analysis and Integration (PA&I) performed planning and integration activities to support management of the various Flat-Plate Solar Array (FSA) Project R&D activities. Technical and economic goals were established by PA&I for each R&D task within the project to coordinate the thrust toward the National Photovoltaic Program goals. A sophisticated computer modeling capability was developed to assess technical progress toward meeting the economic goals. These models included a manufacturing facility simulation, a photovoltaic power station simulation and a decision aid model incorporating uncertainty. This family of analysis tools was used to track the progress of the technology and to explore the effects of alternative technical paths. Numerous studies conducted by PA&I signaled the achievement of milestones or were the foundation of major FSA project and national program decisions. The most important PA&I activities during the project history are summarized. The PA&I planning function is discussed and how it relates to project direction and important analytical models developed by PA&I for its analytical and assessment activities are reviewed.

Evaluation of novel PMTs of worldwide best parameters for the CTA project

NASA Astrophysics Data System (ADS)

Mirzoyan, R.; Müller, D.; Hose, J.; Menzel, U.; Nakajima, D.; Takahashi, M.; Teshima, M.; Toyama, T.; Yamamoto, T.

2017-02-01

Photomultiplier Tubes (PMT) are the most widespread detectors for measuring fast and faint light signals. About six years ago, we started an improvement program for the PMT candidates for the Cherenkov Telescope Array (CTA) project in cooperation with the companies Hamamatsu Photonics K.K. (Japan) and Electron Tubes Enterprises Ltd. (England). CTA is the next major Imaging Atmospheric Cherenkov Telescopes array for ground-based high energy gamma-ray astrophysics. A total of ∼ 100 telescopes of sizes of 23 m, 12 m and 4 m in diameter will be built in northern and southern hemispheres. For CTA we need PMTs with the highest quantum efficiency and photoelectron collection efficiency, short pulse width of a few ns, low transit time spread and very low afterpulsing. The manufacturers were able to produce 1.5‧ PMTs of enhanced peak quantum efficiency of ∼ 40 % . These collect up to 95-98% of photoelectrons onto the first dynode for the wavelengths ≥ 400 nm . A pulse width of ≤ 3 ns has been achieved at the selected operational gain of 40k. The afterpulsing for a threshold of ≥ 4 photoelectrons is dramatically reduced, down to the level of 0.02%. We will report on the measurements of 1.5‧ PMTs from Hamamatsu and Electron Tubes Enterprises as candidate PMTs for the CTA project. The novel 1.5‧ PMTs have the worldwide best parameters.

A Demonstration of Big Data Technology for Data Intensive Earth Science (Invited)

NASA Astrophysics Data System (ADS)

Kuo, K.; Clune, T.; Ramachandran, R.; Rushing, J.; Fekete, G.; Lin, A.; Doan, K.; Oloso, A. O.; Duffy, D.

2013-12-01

Big Data technologies exhibit great potential to change the way we conduct scientific investigations, especially analysis of voluminous and diverse data sets. Obviously, not all Big Data technologies are applicable to all aspects of scientific data analysis. Our NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) project, Automated Event Service (AES), pioneers the exploration of Big Data technologies for data intensive Earth science. Since Earth science data are largely stored and manipulated in the form of multidimensional arrays, the project first evaluates array performance of several candidate Big Data technologies, including MapReduce (Hadoop), SciDB, and a custom-built Polaris system, which have one important feature in common: shared nothing architecture. The evaluation finds SicDB to be the most promising. In this presentation, we demonstrate SciDB using a couple of use cases, each operating on a distinct data set in the regular latitude-longitude grid. The first use case is the discovery and identification of blizzards using NASA's Modern Era Retrospective-analysis for Research and Application (MERRA) data sets. The other finds diurnal signals in the same 8-year period using SSMI data from three different instruments with different equator crossing times by correlating their retrieved parameters. In addition, the AES project is also developing a collaborative component to enable the sharing of event queries and results. Preliminary capabilities will be presented as well.

Nanophotonic projection system.

PubMed

Aflatouni, Firooz; Abiri, Behrooz; Rekhi, Angad; Hajimiri, Ali

2015-08-10

Low-power integrated projection technology can play a key role in development of low-cost mobile devices with built-in high-resolution projectors. Low-cost 3D imaging and holography systems are also among applications of such a technology. In this paper, an integrated projection system based on a two-dimensional optical phased array with fast beam steering capability is reported. Forward biased p-i-n phase modulators with 200MHz bandwidth are used per each array element for rapid phase control. An optimization algorithm is implemented to compensate for the phase dependent attenuation of the p-i-n modulators. Using rapid vector scanning technique, images were formed and recorded within a single snapshot of the IR camera.

Laser beam projection with adaptive array of fiber collimators. II. Analysis of atmospheric compensation efficiency.

PubMed

Lachinova, Svetlana L; Vorontsov, Mikhail A

2008-08-01

We analyze the potential efficiency of laser beam projection onto a remote object in atmosphere with incoherent and coherent phase-locked conformal-beam director systems composed of an adaptive array of fiber collimators. Adaptive optics compensation of turbulence-induced phase aberrations in these systems is performed at each fiber collimator. Our analysis is based on a derived expression for the atmospheric-averaged value of the mean square residual phase error as well as direct numerical simulations. Operation of both conformal-beam projection systems is compared for various adaptive system configurations characterized by the number of fiber collimators, the adaptive compensation resolution, and atmospheric turbulence conditions.

Switched Antenna Array Tile for Real-Time Microwave Imaging Aperture

DTIC Science & Technology

2016-06-26

Switched Antenna Array Tile for Real -Time Microwave Imaging Aperture William F. Moulder, Janusz J. Majewski, Charles M. Coldwell, James D. Krieger...Fast Imaging Algorithm 10mm 250mm Switched Array Tile Fig. 1. Diagram of real -time imaging array, with fabricated antenna tile. except for antenna...formed. IV. CONCLUSIONS A switched array tile to be used in a real time imaging aperture has been presented. Design and realization of the tile were

Large-N Nodal Seismic Deployment at Mount St Helens

NASA Astrophysics Data System (ADS)

Hansen, S. M.; Schmandt, B.; Vidale, J. E.; Creager, K. C.; Levander, A.; Kiser, E.; Barklage, M.; Hollis, D.

2014-12-01

In late July of 2014 over 900 autonomous short period seismometers were deployed within 12 km of the summit crater at Mount St Helens. In concert with the larger iMUSH experiment, these data constitute the largest seismic interrogation of an active volcano ever conducted. The array was deployed along the road and trail system of the national volcanic monument and adjacent regions with an average station spacing of 250 meters and included several station clusters with increased sampling density. The 10 Hz phones recorded the vertical component wavefield continuously at 250 Hz sampling rate over a period of approximately two weeks. During the recording time, the Pacific Northwest Seismic Network detected ~65 earthquakes within the array footprint ranging in magnitude from -0.9 to 1.1, the majority of which were located beneath the crater at less than 10 km depth. In addition to the natural seismicity, 23 explosion sources from the iMUSH active source experiment were recorded, several of which exceeded magnitude 2. Preliminary results for this project will include an expanded event catalog as the array should significantly reduce the detection threshold. The sheer number of instruments allows for stacking of station clusters producing high signal-to-noise beam traces which can be used for event triggering and for creating waveform templates to measure relative travel-times across the array via cross-correlation. The ability of the array to estimate focal mechanisms from event radiation patterns and delineate complex path effects will also be investigated. The density and azimuthal coverage provide by this array offers an excellent opportunity to investigate short-wavelength variations of the seismic wavefield in a complex geologic environment. Previous seismic tomography results suggest the presence of a shallow magma chamber at 1-3 km depth near the region of shallow seismicity as evidenced by a P wave low-velocity anomaly of at least -5.5% [Waite and Moran, 2009]. The proximity of the array as well as the event distribution make it possible to investigate wavefield distortion and scattering due to the potential magma chamber, including s-wave blockage as has been observed in other systems.

Enhancing Discovery, Search, and Access of NASA Hydrological Data by Leveraging GEOSS

NASA Technical Reports Server (NTRS)

Teng, William L.

2015-01-01

An ongoing NASA-funded project has removed a longstanding barrier to accessing NASA data (i.e., accessing archived time-step array data as point-time series) for selected variables of the North American and Global Land Data Assimilation Systems (NLDAS and GLDAS, respectively) and other EOSDIS (Earth Observing System Data Information System) data sets (e.g., precipitation, soil moisture). These time series (data rods) are pre-generated. Data rods Web services are accessible through the CUAHSI Hydrologic Information System (HIS) and the Goddard Earth Sciences Data and Information Services Center (GES DISC) but are not easily discoverable by users of other non-NASA data systems. The Global Earth Observation System of Systems (GEOSS) is a logical mechanism for providing access to the data rods. An ongoing GEOSS Water Services project aims to develop a distributed, global registry of water data, map, and modeling services cataloged using the standards and procedures of the Open Geospatial Consortium and the World Meteorological Organization. The ongoing data rods project has demonstrated the feasibility of leveraging the GEOSS infrastructure to help provide access to time series of model grid information or grids of information over a geographical domain for a particular time interval. A recently-begun, related NASA-funded ACCESS-GEOSS project expands on these prior efforts. Current work is focused on both improving the performance of the generation of on-the-fly (OTF) data rods and the Web interfaces from which users can easily discover, search, and access NASA data.

SU-C-207-01: Four-Dimensional Inverse Geometry Computed Tomography: Concept and Its Validation

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

Kim, K; Kim, D; Kim, T

2015-06-15

Purpose: In past few years, the inverse geometry computed tomography (IGCT) system has been developed to overcome shortcomings of a conventional computed tomography (CT) system such as scatter problem induced from large detector size and cone-beam artifact. In this study, we intend to present a concept of a four-dimensional (4D) IGCT system that has positive aspects above all with temporal resolution for dynamic studies and reduction of motion artifact. Methods: Contrary to conventional CT system, projection data at a certain angle in IGCT was a group of fractionated narrow cone-beam projection data, projection group (PG), acquired from multi-source array whichmore » have extremely short time gap of sequential operation between each of sources. At this, for 4D IGCT imaging, time-related data acquisition parameters were determined by combining multi-source scanning time for collecting one PG with conventional 4D CBCT data acquisition sequence. Over a gantry rotation, acquired PGs from multi-source array were tagged time and angle for 4D image reconstruction. Acquired PGs were sorted into 10 phase and image reconstructions were independently performed at each phase. Image reconstruction algorithm based upon filtered-backprojection was used in this study. Results: The 4D IGCT had uniform image without cone-beam artifact on the contrary to 4D CBCT image. In addition, the 4D IGCT images of each phase had no significant artifact induced from motion compared with 3D CT. Conclusion: The 4D IGCT image seems to give relatively accurate dynamic information of patient anatomy based on the results were more endurable than 3D CT about motion artifact. From this, it will be useful for dynamic study and respiratory-correlated radiation therapy. This work was supported by the Industrial R&D program of MOTIE/KEIT [10048997, Development of the core technology for integrated therapy devices based on real-time MRI guided tumor tracking] and the Mid-career Researcher Program (2014R1A2A1A10050270) through the National Research Foundation of Korea funded by the Ministry of Science, ICT&Future Planning.« less

LSA: Low-cost Solar Array project

NASA Technical Reports Server (NTRS)

1978-01-01

Topics discussed include silicon material processing; large-area silicon sheet development; encapsulation materials testing and development; project engineering and operations activities, and manufacturing techniques. The steps taken to integrate these efforts, are described.

Disposable gold coated pyramidal SERS sensor on the plastic platform.

PubMed

Oo, S Z; Siitonen, S; Kontturi, V; Eustace, D A; Charlton, M D B

2016-01-11

In this paper we investigate suitability of arrays of gold coated pyramids for surface-enhanced Raman scattering (SERS) sensing applications. Pyramidarrays composed of 1000 nm pit size with 1250 nm pitch lengthwerereplicated on a plastic substrate by roll-to-roll (R2R) ultraviolet (UV) embossing. The level of SERS enhancement, and qualitative performance provided by the new substrate is investigated by comparing Raman spectrum of benzenethiol (BTh) test molecules to the benchmark Klarite SERS substrate which comprises inverted pyramid arrays(1500 nm pit size with 2000 nm pitch length) fabricated on a silicon substrate. The new substrate is found to provide upto 11 times increase in signal in comparison to the inverted pyramid (IV-pyramid) arrays fabricated on an identical plastic substrate. Numerical simulation and experimental evidence suggest that strongly confined electromagnetic fields close to the base of the pyramids, are mainly responsible for the Raman enhancement factor, instead of the fields localized around the tip. Unusually strong plasmon fields are projected upto 200nm from the sidewalls at the base of the pyramid increasing the cross sectional sensing volume.

Demonstration Of Fast, Single-Shot Photocathode QE Mapping Method Using Mla Pattern Beam

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

Wisniewski, E. E.; Conde, M.; Doran, D. S.

Quantum efficiency (QE) is the chief figure of merit in the characterization of photocathodes. Semiconductor photocathodes, especially when used in high rep-rate photoinjectors, are known to show QE degradation over time and must be replaced. The totalQE is the basic diagnosticwhich is used widely and is easy to obtain. However, a QE map indicating variations of QE across the cathode surface has greater utility. It can quickly diagnose problems of QE inhomogeneity. Most QE mapping techniques require hours to complete and are thus disruptive to a user facility schedule. A fast, single-shot method has been proposed using a micro-lens arraymore » (MLA) generated QE map. In this paper we report the implementation of the method at Argonne Wakefield Accelerator facility. A micro-lens array (MLA) is used to project an array of beamlets onto the photocathode. The resulting photoelectron beam in the form of an array of electron beamlets is imaged at a YAG screen. Four synchronized measurements are made and the results used to produce a QE map of the photocathode.« less

Big-Data Perspective to Operating an SKA-Type Synthesis Array Radio Telescope

NASA Astrophysics Data System (ADS)

Shanmugha Sundaram, GA

2015-08-01

Of the two forerunner sites, viz. Australia and South Africa, where pioneering advancements to state-of-the-art in synthesis array radio astronomy instrumentation are being attempted in the form of pathfinders to the Square Kilometer Array (SKA), for its eventual deployment, a diversity of site-dependent topology and design metrics exists. Towards addressing some of the fundamental mysteries in physics at the micro- and macro-cosm levels, that form the Key Science Projects (KSPs) for the SKA, and interfacing them to an optimally designed array conguration, a critical evaluation of their radio imaging capabilities and metrics becomes paramount. Here, the various KSPs and instrument design specifications are discussed, for relative merits and adaptability to either site, from invoking well-founded and established array-design and optimization principles designed into a customized software tool. Since the problem of array design is one that encompasses variables on several scales such as separation distances between the radio interferometric pair (termed the baseline), factors such as redundancy, flux and phase calibration, bandwidth, integration time, clock synchronization for the correlation process at the detector, and many other ambient-defined parameters, there is a significant component of big data involved in the complex visibilities that are to be Fourier transformed from the spatial to the radio-sky domain (to generate a radio sky map) using vast computational infrastructure, with robust data connectivity and data handling facilities to support this. A crucial requirement exists to make the general public aware of the implications of such a massive scale scientific and technological venture, which shall be the focus of this presentation.

Performance of an underwater acoustic volume array using time-reversal focusing.

PubMed

Root, Joseph A; Rogers, Peter H

2002-11-01

Time reversal permits acoustic focusing and beam forming in inhomogeneous and/or high-scattering environments. A volumetric array geometry can suppress back lobes and can fit a large, powerful array of elements into small spaces, like the free-water spaces on submarines. This research investigates applying the time-reversal method to an underwater acoustic volume array. The experiments evaluate the focusing performance of a 27-element volume array when different scattering structures are present within the volume of the array. The array is arranged in a 3x3x3 cubic matrix configuration with 18.75-cm vertical and horizontal element spacing. The system utilizes second-derivative Gaussian pulses to focus on a point 30 cm from the array. Results include a comparison between time-reversal focusing and standard focusing, an evaluation of the volume array's ability to suppress back lobes, and an analysis of how different scattering environments affect focal region size. Potential underwater applications for a volume array using time reversal include acoustic imaging, naval mine hunting, sonar, and underwater communications.

Performance of an underwater acoustic volume array using time-reversal focusing

NASA Astrophysics Data System (ADS)

Root, Joseph A.; Rogers, Peter H.

2002-11-01

Time reversal permits acoustic focusing and beam forming in inhomogeneous and/or high-scattering environments. A volumetric array geometry can suppress back lobes and can fit a large, powerful array of elements into small spaces, like the free-water spaces on submarines. This research investigates applying the time-reversal method to an underwater acoustic volume array. The experiments evaluate the focusing performance of a 27-element volume array when different scattering structures are present within the volume of the array. The array is arranged in a 3 x3 x3 cubic matrix configuration with 18.75-cm vertical and horizontal element spacing. The system utilizes second-derivative Gaussian pulses to focus on a point 30 cm from the array. Results include a comparison between time-reversal focusing and standard focusing, an evaluation of the volume array's ability to suppress back lobes, and an analysis of how different scattering environments affect focal region size. Potential underwater applications for a volume array using time reversal include acoustic imaging, naval mine hunting, sonar, and underwater communications. copyright 2002 Acoustical Society of America.

Status of LOFAR Data in HDF5 Format

NASA Astrophysics Data System (ADS)

Alexov, A.; Schellart, P.; ter Veen, S.; van der Akker, M.; Bähren, L.; Greissmeier, J.-M.; Hessels, J. W. T.; Mol, J. D.; Renting, G. A.; Swinbank, J.; Wise, M.

2012-09-01

The Hierarchical Data Format, version 5 (HDF5) is a data model, library, and file format for storing and managing data. It is designed for flexible and efficient I/O and for high volume, complex data. The Low Frequency Array (LOFAR) project is solving the challenge of data size and complexity using HDF5. Most of LOFAR's standard data products will be stored using HDF5; the beam-formed time-series data and transient buffer board data have already transitioned from project-specific binary format to HDF5. We report on our effort to pave the way towards new astronomical data encapsulation using HDF5, which can be used by future ground and space projects. The LOFAR project has formed a collaboration with NRAO, the Virtual Astronomical Observatory (VAO) and the HDF Group to obtain funding for a full-time staff member to work on documenting and developing standards for astronomical data written in HDF5. We hope our effort will enhance HDF5 visibility and usage within the community, specifically for LSST, the SKA pathfinders (ASKAP, MeerKAT, MWA, LWA), and other major new radio telescopes such as EVLA, ALMA, and eMERLIN.

Dynamical Imaging with Interferometry

NASA Astrophysics Data System (ADS)

Johnson, Michael D.; Bouman, Katherine L.; Blackburn, Lindy; Chael, Andrew A.; Rosen, Julian; Shiokawa, Hotaka; Roelofs, Freek; Akiyama, Kazunori; Fish, Vincent L.; Doeleman, Sheperd S.

2017-12-01

By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy. However, at any given moment, a VLBI array only sparsely samples the information necessary to form an image. Conventional imaging techniques partially overcome this limitation by making the assumption that the observed cosmic source structure does not evolve over the duration of an observation, which enables VLBI networks to accumulate information as Earth rotates and changes the projected array geometry. Although this assumption is appropriate for nearly all VLBI, it is almost certainly violated for submillimeter observations of the Galactic center supermassive black hole, Sagittarius A* (Sgr A*), which has a gravitational timescale of only ∼ 20 s and exhibits intrahour variability. To address this challenge, we develop several techniques to reconstruct dynamical images (“movies”) from interferometric data. Our techniques are applicable to both single-epoch and multiepoch variability studies, and they are suitable for exploring many different physical processes including flaring regions, stable images with small time-dependent perturbations, steady accretion dynamics, or kinematics of relativistic jets. Moreover, dynamical imaging can be used to estimate time-averaged images from time-variable data, eliminating many spurious image artifacts that arise when using standard imaging methods. We demonstrate the effectiveness of our techniques using synthetic observations of simulated black hole systems and 7 mm Very Long Baseline Array observations of M87, and we show that dynamical imaging is feasible for Event Horizon Telescope observations of Sgr A*.

Hydrogen Epoch of Reinozation Array (HERA) Calibrated FFT Correlator Simulation

NASA Astrophysics Data System (ADS)

Salazar, Jeffrey David; Parsons, Aaron

2018-01-01

The Hydrogen Epoch of Reionization Array (HERA) project is an astronomical radio interferometer array with a redundant baseline configuration. Interferometer arrays are being used widely in radio astronomy because they have a variety of advantages over single antenna systems. For example, they produce images (visibilities) closely matching that of a large antenna (such as the Arecibo observatory), while both the hardware and maintenance costs are significantly lower. However, this method has some complications; one being the computational cost of correlating data from all of the antennas. A correlator is an electronic device that cross-correlates the data between the individual antennas; these are what radio astronomers call visibilities. HERA, being in its early stages, utilizes a traditional correlator system. The correlator cost scales as N2, where N is the number of antennas in the array. The purpose of a redundant baseline configuration array setup is for the use of a more efficient Fast Fourier Transform (FFT) correlator. FFT correlators scale as Nlog2N. The data acquired from this sort of setup, however, inherits geometric delay and uncalibrated antenna gains. This particular project simulates the process of calibrating signals from astronomical sources. Each signal “received” by an antenna in the simulation is given random antenna gain and geometric delay. The “linsolve” Python module was used to solve for the unknown variables in the simulation (complex gains and delays), which then gave a value for the true visibilities. This first version of the simulation only mimics a one dimensional redundant telescope array detecting a small amount of sources located in the volume above the antenna plane. Future versions, using GPUs, will handle a two dimensional redundant array of telescopes detecting a large amount of sources in the volume above the array.

Reconfigurable signal processor designs for advanced digital array radar systems

NASA Astrophysics Data System (ADS)

Suarez, Hernan; Zhang, Yan (Rockee); Yu, Xining

2017-05-01

The new challenges originated from Digital Array Radar (DAR) demands a new generation of reconfigurable backend processor in the system. The new FPGA devices can support much higher speed, more bandwidth and processing capabilities for the need of digital Line Replaceable Unit (LRU). This study focuses on using the latest Altera and Xilinx devices in an adaptive beamforming processor. The field reprogrammable RF devices from Analog Devices are used as analog front end transceivers. Different from other existing Software-Defined Radio transceivers on the market, this processor is designed for distributed adaptive beamforming in a networked environment. The following aspects of the novel radar processor will be presented: (1) A new system-on-chip architecture based on Altera's devices and adaptive processing module, especially for the adaptive beamforming and pulse compression, will be introduced, (2) Successful implementation of generation 2 serial RapidIO data links on FPGA, which supports VITA-49 radio packet format for large distributed DAR processing. (3) Demonstration of the feasibility and capabilities of the processor in a Micro-TCA based, SRIO switching backplane to support multichannel beamforming in real-time. (4) Application of this processor in ongoing radar system development projects, including OU's dual-polarized digital array radar, the planned new cylindrical array radars, and future airborne radars.

Optical sectioning microscopes with no moving parts using a micro-stripe array light emitting diode.

PubMed

Poher, V; Zhang, H X; Kennedy, G T; Griffin, C; Oddos, S; Gu, E; Elson, D S; Girkin, M; French, P M W; Dawson, M D; Neil, M A

2007-09-03

We describe an optical sectioning microscopy system with no moving parts based on a micro-structured stripe-array light emitting diode (LED). By projecting arbitrary line or grid patterns onto the object, we are able to implement a variety of optical sectioning microscopy techniques such as grid-projection structured illumination and line scanning confocal microscopy, switching from one imaging technique to another without modifying the microscope setup. The micro-structured LED and driver are detailed and depth discrimination capabilities are measured and calculated.

Xatcobeo: Small Mechanisms for CubeSat Satellites - Antenna and Solar Array Deployment

NASA Technical Reports Server (NTRS)

EncinasPlaza, Jose Miguel; VilanVilan, Jose Antonio; AquadoAgelet, Fernando; BrandiaranMancheno, Javier; LopezEstevez, Miguel; MartinezFernandez, Cesar; SarmientoAres, Fany

2010-01-01

The Xatcobeo project, which includes the mechanisms dealt with here, is principally a university project to design and construct a CubeSat 1U-type satellite. This work describes the design and operational features of the system for antenna storage and deployment, and the design and simulations of the solar array deployment system. It explains the various problems faced and solutions adopted, with a view to providing valid data for any other applications that could find them useful, be they of a similar nature or not.

A summary report on the Flat-Plate Solar Array Project Workshop on Transparent Conducting Polymers

NASA Technical Reports Server (NTRS)

Kachare, R.; Moacanin, J.

1985-01-01

The proceedings and technical discussions of a workshop on Transparent Conducting Polymers (TCP) for solar cell applications are reported. This is in support of the Device Research Task of the Flat-Flate Solar Array Project. The workshop took place on January 11 and 12, 1985, in Santa Barbara, California. Participants included university and industry researchers. The discussions focused on the electronic and optical properties of TCP, and on experimental issues and problems that should be addressed for high-efficiency solar cell application.

Electrostatically actuatable light modulating device

DOEpatents

Koehler, Dale R.

1991-01-01

The electrostatically actuatable light modulator utilizes an opaque substrate plate patterned with an array of aperture cells, the cells comprised of physically positionable dielectric shutters and electrostatic actuators. With incorporation of a light source and a viewing screen, a projection display system is effected. Inclusion of a color filter array aligned with the aperture cells accomplishes a color display. The system is realized in terms of a silicon based manufacturing technology allowing fabrication of a high resolution capability in a physically small device which with the utilization of included magnification optics allows both large and small projection displays.

High Aspect Ratio Semiconductor Heterojunction Solar Cells

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

Redwing, Joan; Mallouk, Tom; Mayer, Theresa

2013-05-17

The project focused on the development of high aspect ratio silicon heterojunction (HARSH) solar cells. The solar cells developed in this study consisted of high density vertical arrays of radial junction silicon microwires/pillars formed on Si substrates. Prior studies have demonstrated that vertical Si wire/pillar arrays enable reduced reflectivity and improved light trapping characteristics compared to planar solar cells. In addition, the radial junction structure offers the possibility of increased carrier collection in solar cells fabricated using material with short carrier diffusion lengths. However, the high junction and surface area of radial junction Si wire/pillar array devices can be problematicmore » and lead to increased diode leakage and enhanced surface recombination. This study investigated the use of amorphous hydrogenated Si in the form of a heterojunction-intrinsic-thin layer (HIT) structure as a junction formation method for these devices. The HIT layer structure has widely been employed to reduce surface recombination in planar crystalline Si solar cells. Consequently, it was anticipated that it would also provide significant benefits to the performance of radial junction Si wire/pillar array devices. The overall goals of the project were to demonstrate a HARSH cell with a HIT-type structure in the radial junction Si wire/pillar array configuration and to develop potentially low cost pathways to fabricate these devices. Our studies demonstrated that the HIT structure lead to significant improvements in the open circuit voltage (V oc>0.5) of radial junction Si pillar array devices compared to devices fabricated using junctions formed by thermal diffusion or low pressure chemical vapor deposition (LPCVD). In addition, our work experimentally demonstrated that the radial junction structure lead to improvements in efficiency compared to comparable planar devices for devices fabricated using heavily doped Si that had reduced carrier diffusion lengths. Furthermore, we made significant advances in employing the bottom-up vapor-liquid-solid (VLS) growth technique for the fabrication of the Si wire arrays. Our work elucidated the effects of growth conditions and substrate pattern geometry on the growth of large area Si microwire arrays grown with SiCl4. In addition, we also developed a process to grow p-type Si nanowire arrays using aluminum as the catalyst metal instead of gold. Finally, our work demonstrated the feasibility of growing vertical arrays of Si wires on non-crystalline glass substrates using polycrystalline Si template layers. The accomplishments demonstrated in this project will pave the way for future advances in radial junction wire array solar cells.« less

Constraining Alternative Theories of Gravity Using Pulsar Timing Arrays

NASA Astrophysics Data System (ADS)

Cornish, Neil J.; O'Beirne, Logan; Taylor, Stephen R.; Yunes, Nicolás

2018-05-01

The opening of the gravitational wave window by ground-based laser interferometers has made possible many new tests of gravity, including the first constraints on polarization. It is hoped that, within the next decade, pulsar timing will extend the window by making the first detections in the nanohertz frequency regime. Pulsar timing offers several advantages over ground-based interferometers for constraining the polarization of gravitational waves due to the many projections of the polarization pattern provided by the different lines of sight to the pulsars, and the enhanced response to longitudinal polarizations. Here, we show that existing results from pulsar timing arrays can be used to place stringent limits on the energy density of longitudinal stochastic gravitational waves. However, unambiguously distinguishing these modes from noise will be very difficult due to the large variances in the pulsar-pulsar correlation patterns. Existing upper limits on the power spectrum of pulsar timing residuals imply that the amplitude of vector longitudinal (VL) and scalar longitudinal (SL) modes at frequencies of 1/year are constrained, AVL<4 ×10-16 and ASL<4 ×10-17, while the bounds on the energy density for a scale invariant cosmological background are ΩVLh2<4 ×10-11 and ΩSLh2<3 ×10-13.

Constraining Alternative Theories of Gravity Using Pulsar Timing Arrays.

PubMed

Cornish, Neil J; O'Beirne, Logan; Taylor, Stephen R; Yunes, Nicolás

2018-05-04

The opening of the gravitational wave window by ground-based laser interferometers has made possible many new tests of gravity, including the first constraints on polarization. It is hoped that, within the next decade, pulsar timing will extend the window by making the first detections in the nanohertz frequency regime. Pulsar timing offers several advantages over ground-based interferometers for constraining the polarization of gravitational waves due to the many projections of the polarization pattern provided by the different lines of sight to the pulsars, and the enhanced response to longitudinal polarizations. Here, we show that existing results from pulsar timing arrays can be used to place stringent limits on the energy density of longitudinal stochastic gravitational waves. However, unambiguously distinguishing these modes from noise will be very difficult due to the large variances in the pulsar-pulsar correlation patterns. Existing upper limits on the power spectrum of pulsar timing residuals imply that the amplitude of vector longitudinal (VL) and scalar longitudinal (SL) modes at frequencies of 1/year are constrained, A_{VL}<4×10^{-16} and A_{SL}<4×10^{-17}, while the bounds on the energy density for a scale invariant cosmological background are Ω_{VL}h^{2}<4×10^{-11} and Ω_{SL}h^{2}<3×10^{-13}.

An 8.4-GHz dual-maser front-end system for Parkes reimplementation

NASA Technical Reports Server (NTRS)

Trowbridge, D. L.; Loreman, J. R.; Brunzie, T. J.; Quinn, R.

1990-01-01

An 8.4-GHz front-end system consisting of a feedhorn, a waveguide feed assembly, dual masers, and downconverters was reimplemented at Parkes as part of the Parkes Canberra Telemetry Array for the Voyager Neptune encounter. The front-end system was originally assembled by the European Space Agency and installed on the Parkes antenna for the Giotto project. It was also used on a time-sharing basis by the Deep Space Network as part of the Parkes Canberra Telemetry Array to enhance the data return from the Voyager Uranus encounter. At the conclusion of these projects in 1986, part of the system was then shipped to JPL on loan for reimplementation at Parkes for the Voyager Neptune encounter. New design and implementation required to make the system operable at Parkes included new microwave front-end control cabinets, closed-cycle refrigeration monitor system, noise-adding radiometer system, front-end controller assembly, X81 local oscillator multiplier, and refurbishment of the original dual 8.4-GHz traveling-wave masers and waveguide feed system. The front-end system met all requirements during the encounter and was disassembled in October 1989 and returned to JPL.

Improving Interstellar Medium Mitigation in Millisecond PulsarTiming Models for Gravitational Wave Detection Sensitivity

NASA Astrophysics Data System (ADS)

Wilson, Robert C.

2018-01-01

This study aims to increase the sensitivity of pulsar timing arrays (PTAs) used by astronomers ofthe North American Nanohertz Observatory for Gravitational Waves (NANOGrav) to detectgravitational waves (GWs). Millisecond pulsars with many epochs of observations will be used todetermine if dispersive, frequency-dependent pulse time-of-arrival (TOA) delays caused by theinterstellar medium (ISM) can be more accurately predicted over numerous frequency channels.This project will contribute to the ongoing work to detect low-frequency GWs using PTAs. Dataused for this study will be from both the 110m telescope at the Green Bank Observatory in WestVirginia and the 305m telescope at the Arecibo Observatory in Puerto Rico.

Development of a Digital Tracking Array with Single- Channel RSNS and Monopulse Digital Beamforming

DTIC Science & Technology

2010-12-01

Watt CH1 5.05 VDC 4 A, CH2 12 VDC 2.5 A, and CH3 12 VDC 0.2 A Cable 19 Pasternek Cable RG-306 Variable Attenuator 1 Telonic Altair Attenuation Model...for this collection of information is estimated to average 1 hour per response, including the time for reviewing instruction, searching existing data...Management and Budget, Paperwork Reduction Project (0704-0188) Washington DC 20503. 1 . AGENCY USE ONLY (Leave blank) 2. REPORT DATE December 2010 3

A journey through people, places, and projects in equine assisted reproduction.

PubMed

Hinrichs, Katrin

2016-07-01

A research study is a product of not only a question and its pursuit but also the people, places, and facilities available at the time. My work in equine assisted reproduction has progressed from embryo transfer to oocyte maturation, oocyte transfer, intracytoplasmic sperm injection, embryo biopsy, embryo vitrification, and cloning, as a result of collaborations with an array of remarkable people. This is a summary of some of the stories behind the studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Systems Engineering Lessons Learned from Solar Array Structures and Mechanisms Deployment

NASA Technical Reports Server (NTRS)

Vipavetz, Kevin; Kraft, Thomas

2013-01-01

This report has been developed by the National Aeronautics and Space Administration (NASA) Human Exploration and Operations Mission Directorate (HEOMD) Risk Management team in close coordination with the Engineering Directorate at LaRC. This document provides a point-in-time, cumulative, summary of actionable key lessons learned derived from the design project. Lessons learned invariably address challenges and risks and the way in which these areas have been addressed. Accordingly the risk management thread is woven throughout the document.

Development of a Real-Time Hardware-in-the-Loop Power Systems Simulation Platform to Evaluate Commercial Microgrid Controllers

DTIC Science & Technology

2016-02-19

power converter, a solar photovoltaic ( PV ) system with inverter, and eighteen breakers. (Future work will require either validation of these models...custom control software. (For this project, this was done for the energy storage, solar PV , and breakers.) Implement several relay protection functions...for the PV array is given in Section A.3. This profile was generated by applying a decimation/interpolation filter to the signal from a solar flux

TR-1203: Development of a Real-Time Hardware-in-the-Loop Power Systems Simulation Platform to Evaluate Commercial Microgrid Controllers

DTIC Science & Technology

2016-02-23

power converter, a solar photovoltaic ( PV ) system with inverter, and eighteen breakers. (Future work will require either validation of these models or...control software. (For this project, this was done for the energy storage, solar PV , and breakers.) Implement several relay protection functions to...the PV array is given in Section A.3. This profile was generated by applying a decimation/interpolation filter to the signal from a solar flux point

A BGO detector for Positron Emission Profiling in catalysts

NASA Astrophysics Data System (ADS)

Mangnus, A. V. G.; van Ijzendoorn, L. J.; de Goeij, J. J. M.; Cunningham, R. H.; van Santen, R. A.; de Voigt, M. J. A.

1995-05-01

As part of a project to study the reaction kinetics in catalysts, a detector system has been designed and built. The detector will measure in one dimension the activity distribution of positron emitters in catalyst reactors under operational conditions as a function of time. The detector consists of two arrays of ten BGO crystals each and has the flexibility to measure with high sensitivity the activity profile in various reactor sizes; the position resolution that can be reached is 3 mm.

Silicon Based Mid Infrared SiGeSn Heterostructure Emitters and Detectors

DTIC Science & Technology

2016-05-16

have investigated the surface plasmon enhancement of the GeSn p-i-n photodiode using gold metal nanostructures. We have conducted numerical...simulation of the plasmonic structure of 2D nano-hole array to tune the surface plasmon resonance into the absorption range of the GeSn active layer. Such a...diode can indeed be enhanced with the plasmonic structure on top. Within the time span of this project, we have completed one iteration of the process

A Comparison of Earthquake Back-Projection Imaging Methods for Dense Local Arrays, and Application to the 2011 Virginia Aftershock Sequence

NASA Astrophysics Data System (ADS)

Beskardes, G. D.; Hole, J. A.; Wang, K.; Wu, Q.; Chapman, M. C.; Davenport, K. K.; Michaelides, M.; Brown, L. D.; Quiros, D. A.

2016-12-01

Back-projection imaging has recently become a practical method for local earthquake detection and location due to the deployment of densely sampled, continuously recorded, local seismograph arrays. Back-projection is scalable to earthquakes with a wide range of magnitudes from very tiny to very large. Local dense arrays provide the opportunity to capture very tiny events for a range applications, such as tectonic microseismicity, source scaling studies, wastewater injection-induced seismicity, hydraulic fracturing, CO2 injection monitoring, volcano studies, and mining safety. While back-projection sometimes utilizes the full seismic waveform, the waveforms are often pre-processed to overcome imaging issues. We compare the performance of back-projection using four previously used data pre-processing methods: full waveform, envelope, short-term averaging / long-term averaging (STA/LTA), and kurtosis. The goal is to identify an optimized strategy for an entirely automated imaging process that is robust in the presence of real-data issues, has the lowest signal-to-noise thresholds for detection and for location, has the best spatial resolution of the energy imaged at the source, preserves magnitude information, and considers computational cost. Real data issues include aliased station spacing, low signal-to-noise ratio (to <1), large noise bursts and spatially varying waveform polarity. For evaluation, the four imaging methods were applied to the aftershock sequence of the 2011 Virginia earthquake as recorded by the AIDA array with 200-400 m station spacing. These data include earthquake magnitudes from -2 to 3 with highly variable signal to noise, spatially aliased noise, and large noise bursts: realistic issues in many environments. Each of the four back-projection methods has advantages and disadvantages, and a combined multi-pass method achieves the best of all criteria. Preliminary imaging results from the 2011 Virginia dataset will be presented.

Lessons from Cotton: Research Projects Following Development of a Community-based Genotyping Array

USDA-ARS?s Scientific Manuscript database

High-throughput, cost-effective genotyping arrays provide a standardized resource for plant breeding communities that can be used for a wide range of applications at a suitable pace for integrating pertinent information into breeding programs. Traditionally, crop research communities will target dev...

Status of the MARE experiment in Milan

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

Ferri, E.; Arnaboldi, C.; Ceruti, G.

2009-12-16

An international collaboration has grown around the project of Microcalorimeter Arrays for a Rhenium Experiment (MARE) for a direct and calorimetric measurement of the electron antineutrino mass with sub-electronvolt sensitivity.MARE is divided into two phases. The first phase (MARE-1) consists of two independent experiments using the presently available detector technology to reach a sensitivity of m{sub v}{<=}2eV/c{sup 2}. The goal of the second phase (MARE-2) is to achieve a sub-electronvolt sensitivity on the neutrino mass.The Milan MARE-1 experiment is based on arrays of silicon implanted microcalorimeters, produced by NASA/GSFC, with dielectric silver perrhenate absorbers, AgReO{sub 4}. We present here themore » status of MARE-1 in Milan which is starting data taking with 2 arrays (72 detectors). In this configuration a sensitivity of about 5 eV can be achieved in two years. We describe in details the experimental setup which is designed to host up to 8 arrays (288 detectors). With 8 arrays, two years of measurement would improve the sensitivity to about 3 eV. This talk reports on the activity of the group for the MARE project in Milan.« less

The first educational interferometer in Mexico (FEYMANS): A novel project

NASA Astrophysics Data System (ADS)

Villicana Pedraza, Ilhuiyolitzin; Guesten, Rolf; Saucedo Morales, Julio Cesar; Carreto, Francisco; Valdes Estrada, Erik; Wendolyn Blanco Cardenas, Monica; Rodríguez Garza, Carolina B.; Pech Castillo, Gerardo A.; Ángel Vaquerizo, Juan

2016-07-01

An interferometer is composed of several radio telescopes (dishes) separated by a defined distance and used in synchrony. This kind of array produces a superior angular resolution, better than the resolution achieved by a single dish of the same combined area. In this work we propose the First Educational Youth Mexican Array North South, FEYMANS. It consists of an educational interferometer with initially four dishes. This array harvests Mexico's geography by locating each dish at the periphery of the country; creating new scientific links of provincial populations with the capital. The FEYMANS project focus in high school students and their projects on physics, chemistry and astronomy as a final project. Also, it can be used for bachelor theses. The initial and central dish-node is planed to be in Mexico City. After its construction, the efforts will focus to build subsequent nodes, on the Northwest region, Northeast, or Southeast. Region Northwest will give service to Baja California, Sonora and Chihuahua states. Region Northeast will cover Coahuila, Nuevo Leon and Tamaulipas. Finally, region Southeast will give access to Yucatan, Quintana Roo, Campeche, Tabasco and Chiapas. This project has been conceived by young professional astronomers and Mexican experts that will operate each node. Also, we have the technical support of the "Max Planck Institute fuer Radioastronomy in Bonn Germany" and the educational model of the "PARTNeR" project in Spain. This interferometer will be financed by Mexico's Federal Congress and by Mexico City's Legislative Assembly (ALDF).

Design of Hybrid Nanostructural Arrays to Manipulate SERS-Active Substrates by Nanosphere Lithography.

PubMed

Zhao, Xiaoyu; Wen, Jiahong; Zhang, Mengning; Wang, Dunhui; Wang, Yaxin; Chen, Lei; Zhang, Yongjun; Yang, Jinghai; Du, Youwei

2017-03-01

An easy-handling and low-cost method is utilized to controllably fabricate nanopattern arrays as the surface-enhanced Raman scattering (SERS) active substrates with high density of SERS-active areas (hot spots). A hybrid silver array of nanocaps and nanotriangles are prepared by combining magnetron sputtering and plasma etching. By adjusting the etching time of polystyrene (PS) colloid spheres array in silver nanobowls, the morphology of the arrays can be easily manipulated to control the formation and distribution of hot spots. The experimental results show that the hybrid nanostructural arrays have large enhancement factor, which is estimated to be seven times larger than that in the array of nanocaps and three times larger than that in the array of nanorings and nanoparticles. According to the results of finite-difference time-domain simulation, the excellent SERS performance of this array is ascribed to the high density of hot spots and enhanced electromagnetic field.

An in-house manual for building APEX projects using ArcAPEX

USDA-ARS?s Scientific Manuscript database

The Agricultural Policy Environmental eXtender (APEX) provides the foundation for water quality and natural resource analysis across a wide array of USDA initiatives, projects and programs. The model has been utilized in both the national Conservation Effects Assessment Project (CEAP) analysis and ...

New technologies for HWIL testing of WFOV, large-format FPA sensor systems

NASA Astrophysics Data System (ADS)

Fink, Christopher

2016-05-01

Advancements in FPA density and associated wide-field-of-view infrared sensors (>=4000x4000 detectors) have outpaced the current-art HWIL technology. Whether testing in optical projection or digital signal injection modes, current-art technologies for infrared scene projection, digital injection interfaces, and scene generation systems simply lack the required resolution and bandwidth. For example, the L3 Cincinnati Electronics ultra-high resolution MWIR Camera deployed in some UAV reconnaissance systems features 16MP resolution at 60Hz, while the current upper limit of IR emitter arrays is ~1MP, and single-channel dual-link DVI throughput of COTs graphics cards is limited to 2560x1580 pixels at 60Hz. Moreover, there are significant challenges in real-time, closed-loop, physics-based IR scene generation for large format FPAs, including the size and spatial detail required for very large area terrains, and multi - channel low-latency synchronization to achieve the required bandwidth. In this paper, the author's team presents some of their ongoing research and technical approaches toward HWIL testing of large-format FPAs with wide-FOV optics. One approach presented is a hybrid projection/injection design, where digital signal injection is used to augment the resolution of current-art IRSPs, utilizing a multi-channel, high-fidelity physics-based IR scene simulator in conjunction with a novel image composition hardware unit, to allow projection in the foveal region of the sensor, while non-foveal regions of the sensor array are simultaneously stimulated via direct injection into the post-detector electronics.

Chapter 12 - Mapping wildland fuel across large regions for the LANDFIRE Prototype Project

Treesearch

Robert E. Keane; Tracey Frescino; Matthew C. Reeves; Jennifer L. Long

2006-01-01

The Landscape Fire and Resource Management Planning Tools Prototype Project, or LANDFIRE Prototype Project, required that the entire array of wildland fuel characteristics be mapped to provide fire and landscape managers with consistent baseline geo-spatial information to plan projects for hazardous fuel mitigation and to improve public and firefighter safety. Fuel...

TSAR User’s Manual: A Program for Assessing the Effects of Conventional and Chemical Attacks on Sortie Generation. Volume 3. Variable and Array Definitions, and other Program Aids

DTIC Science & Technology

1990-09-01

array. LTHPER Length of the MPPERS array. LTHQPA Length of the QPA array. LTHXRT Length of the XROOT array. MAXACN Maximum number of aircraft that can...3 Time remaining until the ready-to-fly time at time of report Number of XROOT Array Entries (GENERATED) NROOT (MAXT) The total number of entries in...the XROOT array for each aircraft type. AIS Station Status NSTAT (NOSTAT, I, MAXB) I = 1 Total number of stations of each type on base = 2 Number in

An Efficient, FPGA-Based, Cluster Detection Algorithm Implementation for a Strip Detector Readout System in a Time Projection Chamber Polarimeter

NASA Technical Reports Server (NTRS)

Gregory, Kyle J.; Hill, Joanne E. (Editor); Black, J. Kevin; Baumgartner, Wayne H.; Jahoda, Keith

2016-01-01

A fundamental challenge in a spaceborne application of a gas-based Time Projection Chamber (TPC) for observation of X-ray polarization is handling the large amount of data collected. The TPC polarimeter described uses the APV-25 Application Specific Integrated Circuit (ASIC) to readout a strip detector. Two dimensional photoelectron track images are created with a time projection technique and used to determine the polarization of the incident X-rays. The detector produces a 128x30 pixel image per photon interaction with each pixel registering 12 bits of collected charge. This creates challenging requirements for data storage and downlink bandwidth with only a modest incidence of photons and can have a significant impact on the overall mission cost. An approach is described for locating and isolating the photoelectron track within the detector image, yielding a much smaller data product, typically between 8x8 pixels and 20x20 pixels. This approach is implemented using a Microsemi RT-ProASIC3-3000 Field-Programmable Gate Array (FPGA), clocked at 20 MHz and utilizing 10.7k logic gates (14% of FPGA), 20 Block RAMs (17% of FPGA), and no external RAM. Results will be presented, demonstrating successful photoelectron track cluster detection with minimal impact to detector dead-time.

Microwave power transmitting phased array antenna research project

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1978-01-01

An initial design study and the development results of an S band RF power transmitting phased array antenna experiment system are presented. The array was to be designed, constructed and instrumented to permit wireless power transmission technology evaluation measurements. The planned measurements were to provide data relative to the achievable performance in the state of the art of flexible surface, retrodirective arrays, as a step in technically evaluating the satellite power system concept for importing to earth, via microwave beams, the nearly continuous solar power available in geosynchronous orbit. Details of the microwave power transmitting phased array design, instrumentation approaches, system block diagrams, and measured component and breadboard characteristics achieved are presented.

26+ Year Old Photovoltaic Power Plant: Degradation and Reliability Evaluation of Crystalline Silicon Modules -- South Array

NASA Astrophysics Data System (ADS)

Olakonu, Kolapo

As the use of photovoltaic (PV) modules in large power plants continues to increase globally, more studies on degradation, reliability, failure modes, and mechanisms of field aged modules are needed to predict module life expectancy based on accelerated lifetime testing of PV modules. In this work, a 26+ year old PV power plant in Phoenix, Arizona has been evaluated for performance, reliability, and durability. The PV power plant, called Solar One, is owned and operated by John F. Long's homeowners association. It is a 200 kW dc, standard test conditions (STC) rated power plant comprised of 4000 PV modules or frameless laminates, in 100 panel groups (rated at 175 kW ac). The power plant is made of two center-tapped bipolar arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the south array and the other thesis presents the results obtained on the north array. Each of these two arrays is made of four sub arrays, the east sub arrays (positive and negative polarities) and the west sub arrays (positive and negative polarities), making up eight sub arrays. The evaluation and analyses of the power plant included in this thesis consists of: visual inspection, electrical performance measurements, and infrared thermography. A possible presence of potential induced degradation (PID) due to potential difference between ground and strings was also investigated. Some installation practices were also studied and found to contribute to the power loss observed in this investigation. The power output measured in 2011 for all eight sub arrays at STC is approximately 76 kWdc and represents a power loss of 62% (from 200 kW to 76 kW) over 26+ years. The 2011 measured power output for the four south sub arrays at STC is 39 kWdc and represents a power loss of 61% (from 100 kW to 39 kW) over 26+ years. Encapsulation browning and non-cell interconnect ribbon breakages were determined to be the primary causes for the power loss.

Phase 2 of the Array Automated Assembly Task for the Low Cost Silicon Solar Array Project

NASA Technical Reports Server (NTRS)

Wihl, M.; Torro, J.; Scheinine, A.; Anderson, J.

1978-01-01

An automated process sequence, to manufacture photovoltaic modules at a capacity of approximately 500 MW per year at a cost of approximately $0.50 per peak watt is described. Verification tests were performed and are reported along with cost predictions.

76 FR 8724 - First Light Hydro Generating Company; Notice of Application Accepted for Filing, Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-15

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 2485-059] First Light Hydro..., Federal Energy Regulatory Commission, 888 First Street, NE., Washington, DC 20426. Commenters can submit... photovoltaic solar array will provide power to Northfield Mountain Visitor's Center. The solar array would be...

Designing, Developing and Implementing WWW-Based Distance Learning.

ERIC Educational Resources Information Center

Riley, Peter C.

The rapid advancement of communication technologies is resulting in a wide array of design and development choices for distance learning projects. The 58th Special Operations Wing at Kirtland Air Force Base, New Mexico, is developing a prototype distance learning project designed to serve geographically separated learner populations. Project staff…

LOW COST ORGANIC GAS SENSORS ON PLASTIC FOR DISTRIBUTED ENVIRONMENTAL MONITORING

EPA Science Inventory

This project focused on the development of low-cost arrayed organic sensors for environmental monitoring applications. All of the major goals of the original project have been achieved in the 3-year period of this grant.

In Year 1 of the project, we successfully deve...

Proceedings of the 24th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Tustin, D.

1984-01-01

Progress made by the Flat-Plate Solar Array Project is described. Reports on silicon sheet growth and characterization, silicon material, process development, high-efficiency cells, environmental isolation, engineering sciences, and reliability physics are presented along with copies of visual presentations made at the 24th Project Integration Meeting.

Electricity from photovoltaic solar cells. Flat-Plate Solar Array Project of the US Department of Energy's National Photovoltaics Program: 10 years of progress

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

The objectives were to develop the flat-plate photovoltaic (PV) array technologies required for large-scale terrestrial use late in the 1980s and in the 1990s; advance crystalline silicon PV technologies; develop the technologies required to convert thin-film PV research results into viable module and array technology; and to stimulate transfer of knowledge of advanced PV materials, solar cells, modules, and arrays to the PV community. Progress reached on attaining these goals, along with future recommendations are discussed.

NANOCI-Nanotechnology Based Cochlear Implant With Gapless Interface to Auditory Neurons.

PubMed

Senn, Pascal; Roccio, Marta; Hahnewald, Stefan; Frick, Claudia; Kwiatkowska, Monika; Ishikawa, Masaaki; Bako, Peter; Li, Hao; Edin, Fredrik; Liu, Wei; Rask-Andersen, Helge; Pyykkö, Ilmari; Zou, Jing; Mannerström, Marika; Keppner, Herbert; Homsy, Alexandra; Laux, Edith; Llera, Miguel; Lellouche, Jean-Paul; Ostrovsky, Stella; Banin, Ehud; Gedanken, Aharon; Perkas, Nina; Wank, Ute; Wiesmüller, Karl-Heinz; Mistrík, Pavel; Benav, Heval; Garnham, Carolyn; Jolly, Claude; Gander, Filippo; Ulrich, Peter; Müller, Marcus; Löwenheim, Hubert

2017-09-01

: Cochlear implants (CI) restore functional hearing in the majority of deaf patients. Despite the tremendous success of these devices, some limitations remain. The bottleneck for optimal electrical stimulation with CI is caused by the anatomical gap between the electrode array and the auditory neurons in the inner ear. As a consequence, current devices are limited through 1) low frequency resolution, hence sub-optimal sound quality and 2), large stimulation currents, hence high energy consumption (responsible for significant battery costs and for impeding the development of fully implantable systems). A recently completed, multinational and interdisciplinary project called NANOCI aimed at overcoming current limitations by creating a gapless interface between auditory nerve fibers and the cochlear implant electrode array. This ambitious goal was achieved in vivo by neurotrophin-induced attraction of neurites through an intracochlear gel-nanomatrix onto a modified nanoCI electrode array located in the scala tympani of deafened guinea pigs. Functionally, the gapless interface led to lower stimulation thresholds and a larger dynamic range in vivo, and to reduced stimulation energy requirement (up to fivefold) in an in vitro model using auditory neurons cultured on multi-electrode arrays. In conclusion, the NANOCI project yielded proof of concept that a gapless interface between auditory neurons and cochlear implant electrode arrays is feasible. These findings may be of relevance for the development of future CI systems with better sound quality and performance and lower energy consumption. The present overview/review paper summarizes the NANOCI project history and highlights achievements of the individual work packages.

Nanohertz gravitational wave searches with interferometric pulsar timing experiments.

PubMed

Tinto, Massimo

2011-05-13

We estimate the sensitivity to nano-Hertz gravitational waves of pulsar timing experiments in which two highly stable millisecond pulsars are tracked simultaneously with two neighboring radio telescopes that are referenced to the same timekeeping subsystem (i.e., "the clock"). By taking the difference of the two time-of-arrival residual data streams we can exactly cancel the clock noise in the combined data set, thereby enhancing the sensitivity to gravitational waves. We estimate that, in the band (10(-9)-10(-8))  Hz, this "interferometric" pulsar timing technique can potentially improve the sensitivity to gravitational radiation by almost 2 orders of magnitude over that of single-telescopes. Interferometric pulsar timing experiments could be performed with neighboring pairs of antennas of the NASA's Deep Space Network and the forthcoming large arraying projects.

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

Hann, Jr, Roy W.; Randall, Robert E.

This report describes nekton communities off Freeport, Texas prior to brine disposal based on trawl studies in the period October 1977 to February 1980. Trawling was conducted aboard chartered commercial shrimp trawlers along a transect in depths of 3 to 25 fathoms to describe the general background of nekton communities off Freeport. An array of stations were occupied at the diffuser site in 12 fathoms of water to describe in detail nekton communities near the diffuser. Collections at each station, in general, were made once a month during the day and once a month at night, cruises being about twomore » weeks apart in time. Projected diffuser locations, stations occupied, etc., changed during the course of the project, and the Materials and Methods (Section 4.2) should be consulted for details.« less

Europe, Japan and North America Prepare for Joint Construction of the Giant Radio Telescope "ALMA" in Chile

NASA Astrophysics Data System (ADS)

2001-04-01

Caption : PR Photo 14/01 shows how the ALMA facility may look like when it is ready at Chajnantor. Courtesy NAOJ . Representatives from Europe, Japan, and North America met in Tokyo today and signed a Resolution affirming their mutual intent to construct and operate a giant radio telescope in co-operation with the Republic of Chile, where the telescope will be located. The Atacama Large Millimeter/Submillimeter Array (ALMA) is conceived as a radio telescope comprised of sixty-four transportable 12-meter diameter antennas distributed over an area 14 km in extent. Japanese participation will allow enhanced imaging and spectroscopy, especially at submillimeter wavelengths. By pointing all the antennas in unison toward a single astronomical object, and combining the signals detected by all the antennas with a super-fast digital signal processor, this gigantic radio telescope achieves an imaging detail 10 times better than that of the Hubble Space Telescope. The combined area of all 64 antennas used to collect signals from celestial objects is more than 40 times larger than that available to astronomers using existing submillimeter telescopes. ALMA will be built on the Andean plateau at 5,000 meters altitude near the Atacama Desert of northern Chile. This site provides the exceptionally dry atmospheric conditions necessary for astronomical observations at millimeter and submillimeter wavelengths (wavelengths between the radio and far-infrared spectral regions). Observations with this telescope will have a profound impact on virtually all fields of astrophysical research. The most important targets include the most distant (i.e., the youngest) galaxies as they emerged in the early Universe. These are expected to have become rapidly enshrouded in the dust produced by the first stars; the dust absorbs much of the starlight making the galaxies difficult to see in the optical wavebands, but these same galaxies shine brightly at millimeter and submillimeter wavelengths. In our own Galaxy, ALMA will study the morphology, the motions and the chemistry of dust-enshrouded regions where stars and planets are being formed. ALMA will shed light on these optically `dark' celestial regions that carry key information on the origin of the richness of structure in the Universe and clues to the origin of life. ALMA is a merger of three large projects - The Millimeter Array (MMA) of the United States, the Large Southern Array (LSA) of Europe, and the Large Millimeter and Submillimeter Array (LMSA) of Japan - each of which has been endorsed as the top-priority project in their respective astronomical communities. The European and North American projects were merged into ALMA in 1999 and joint design and development of ALMA began at that time. The National Research Council of Canada is participating with the U.S. in the project. With Japan joining the project as a third partner equal with North America and Europe, and with Chile also taking part, ALMA has become one of the first truly global projects in the history of fundamental science. In the agreement signed today, the partners pledge to use their best efforts to obtain full approval and funding for their participation in ALMA. With the schedule planned, the telescope should be in full operation in 2010. Note [1]: This Press Release is issued jointly by ESO for its members plus UK and Spain, by the National Astronomical Observatory of Japan (NAOJ), by the US National Science Foundation (NSF) and by CONICYT in Chile. The embargo period coincides with a Press Conference by the partners in Tokyo (Japan). Links to earlier Press Releases etc. about ALMA are found on the dedicated webpage.

Development of a Wireless Brain Implant: The Telemetric Electrode Array System (TEAS) Project

DTIC Science & Technology

2001-10-25

8 array connected to an electronic system through a special polyimide flexible cable. The neuronal signals recorded by the electrode array at 1 mm...deposition prior to applying an insulation coating of glass using electron-beam deposition or a biocompatible epoxy through a dipping process. In the case...layer can be made relatively easily, by melting and cooling glass powder or curing biocompatible epoxy, it was desirable to simplify the process and

Summary of flat-plate solar array project documentation. Abstracts of published documents, 1975 to June 1982

NASA Technical Reports Server (NTRS)

1982-01-01

Technologies that will enable the private sector to manufacture and widely use photovoltaic systems for the generation of electricity in residential, commercial, industrial, and government applications at a cost per watt that is competitive with other means is investigated. Silicon refinement processes, advanced silicon sheet growth techniques, solar cell development, encapsulation, automated fabrication process technology, advanced module/array design, and module/array test and evaluation techniques are developed.

A Multiple Use MF/HF Radio Array for Radio Research, Development, and Education

DTIC Science & Technology

2016-04-27

reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: A Multiple Use MF/HF Radio Array for Radio Research , Development...inspiring high school and university- level student projects. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers ...references, in the following categories: (b) Papers published in non-peer-reviewed journals (N/A for none) An MF/HF antenna array for radio and radar imaging

Scheduling with Automatic Resolution of Conflicts

NASA Technical Reports Server (NTRS)

Clement, Bradley; Schaffer, Steve

2006-01-01

DSN Requirement Scheduler is a computer program that automatically schedules, reschedules, and resolves conflicts for allocations of resources of NASA s Deep Space Network (DSN) on the basis of ever-changing project requirements for DSN services. As used here, resources signifies, primarily, DSN antennas, ancillary equipment, and times during which they are available. Examples of project-required DSN services include arraying, segmentation, very-long-baseline interferometry, and multiple spacecraft per aperture. Requirements can include periodic reservations of specific or optional resources during specific time intervals or within ranges specified in terms of starting times and durations. This program is built on the Automated Scheduling and Planning Environment (ASPEN) software system (aspects of which have been described in previous NASA Tech Briefs articles), with customization to reflect requirements and constraints involved in allocation of DSN resources. Unlike prior DSN-resource- scheduling programs that make single passes through the requirements and require human intervention to resolve conflicts, this program makes repeated passes in a continuing search for all possible allocations, provides a best-effort solution at any time, and presents alternative solutions among which users can choose.

The High-Level Interface Definitions in the ASTRI/CTA Mini Array Software System (MASS)

NASA Astrophysics Data System (ADS)

Conforti, V.; Tosti, G.; Schwarz, J.; Bruno, P.; Cefal‘A, M.; Paola, A. D.; Gianotti, F.; Grillo, A.; Russo, F.; Tanci, C.; Testa, V.; Antonelli, L. A.; Canestrari, R.; Catalano, O.; Fiorini, M.; Gallozzi, S.; Giro, E.; Palombara, N. L.; Leto, G.; Maccarone, M. C.; Pareschi, G.; Stringhetti, L.; Trifoglio, M.; Vercellone, S.; Astri Collaboration; Cta Consortium

2015-09-01

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is a Flagship Project funded by the Italian Ministry of Education, University and Research, and led by INAF, the Italian National Institute of Astrophysics. Within this framework, INAF is currently developing an end-to-end prototype, named ASTRI SST-2M, of a Small Size Dual-Mirror Telescope for the Cherenkov Telescope Array, CTA. A second goal of the project is the realization of the ASTRI/CTA mini-array, which will be composed of seven SST-2M telescopes placed at the CTA Southern Site. The ASTRI Mini Array Software System (MASS) is designed to support the ASTRI/CTA mini-array operations. MASS is being built on top of the ALMA Common Software (ACS) framework, which provides support for the implementation of distributed data acquisition and control systems, and functionality for log and alarm management, message driven communication and hardware devices management. The first version of the MASS system, which will comply with the CTA requirements and guidelines, will be tested on the ASTRI SST-2M prototype. In this contribution we present the interface definitions of the MASS high level components in charge of the ASTRI SST-2M observation scheduling, telescope control and monitoring, and data taking. Particular emphasis is given to their potential reuse for the ASTRI/CTA mini-array.

Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

NASA Astrophysics Data System (ADS)

Riahi, Mohammadreza

2016-06-01

In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

Design and Performance of the ARIANNA HRA-3 Neutrino Detector Systems

NASA Astrophysics Data System (ADS)

Barwick, S. W.; Berg, E. C.; Besson, D. Z.; Duffin, T.; Hanson, J. C.; Klein, S. R.; Kleinfelder, S. A.; Ratzlaff, K.; Reed, C.; Roumi, M.; Stezelberger, T.; Tatar, J.; Walker, J.; Young, R.; Zou, L.

2015-10-01

We report on the development, installation, and operation of the first three of seven stations deployed at the ARIANNA site's pilot Hexagonal Radio Array (HRA) in Antarctica. The primary goal of the ARIANNA project is to observe ultrahigh energy ( > 100 PeV) cosmogenic neutrino signatures using a large array of autonomous stations, each 1 km apart on the surface of the Ross Ice Shelf. Sensing radio emissions of 100 MHz to 1 GHz, each station in the array contains RF antennas, amplifiers, 1.92 G-sample/s, 850 MHz bandwidth signal acquisition circuitry, pattern-matching trigger capabilities, an embedded CPU, 32 GB of solid-state data storage, and long-distance wireless and satellite communications. Power is provided by the sun and buffered in LiFePO 4 storage batteries, and each station consumes an average of 7 W of power. Operation on solar power has resulted in ≥58% per calendar-year live-time. The station's pattern-trigger capabilities reduce the trigger rates to a few milli-Hertz with 4-sigma voltage thresholds while retaining good stability and high efficiency for neutrino signals. The timing resolution of the station has been found to be 0.049 ns, RMS, and the angular precision of event reconstructions of signals bounced off of the sea-ice interface of the Ross Ice Shelf ranged from 0.14 to 0.17 °.

Substrate comprising a nanometer-scale projection array

DOEpatents

Cui, Yi; Zhu, Jia; Hsu, Ching-Mei; Connor, Stephen T; Yu, Zongfu; Fan, Shanhui; Burkhard, George

2012-11-27

A method for forming a substrate comprising nanometer-scale pillars or cones that project from the surface of the substrate is disclosed. The method enables control over physical characteristics of the projections including diameter, sidewall angle, and tip shape. The method further enables control over the arrangement of the projections including characteristics such as center-to-center spacing and separation distance.

The 19th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1981-01-01

The Flat-Plate Solar Array Project is described. Project analysis and integration is discussed. Technology research in silicon material, large-area silicon sheet and environmental isolation; cell and module formation; engineering sciences, and module performance and failure analysis. It includes a report on, and copies of visual presentations made at, the 19th Project Integration Meeting held at Pasadena, California, on November 11, 1981.

Design and development of a dedicated mammary and axillary region positron emission tomography system

NASA Astrophysics Data System (ADS)

Doshi, Niraj Kumar

Breast cancer is the second leading cause of cancer death in women. Currently, mammography and physical breast examination, both non-invasive techniques, provide the two most effective methods available for screening potential breast cancer patients. During the management of patients, however, several invasive techniques such as axillary lymph node dissection, core biopsies and lumpectomies, are utilized to determine the stage or malignancy of the disease with significant cost and morbidity associated with them. Positron Emission Tomography (PET), using [F-18] fluorodeoxyglucose (FDG) tracer is a sensitive and non-invasive imaging modality that may be a cost-effective alternative to certain invasive procedures. In this project we have developed a low cost, high performance, dedicated PET camera (maxPET) for mammary and axillary region imaging. The system consists of two 15x15 cm2 planar scintillation detector arrays composed of modular detectors operating in coincidence. The modular detectors are comprised of a 9x9 array of 3x3x20 mm3 lutetiurn oxyorthosilicate (LSO) detector elements, read out by a 5x5 array of position- sensitive photomultiplier tubes. The average measured intrinsic spatial resolution of a detector module is 2.26 mm with a sensitivity of up to 40% for a central point source. The measured coincidence timing resolution for two modules is 2.4 ns. The average energy resolution measured across the entire two detector plates is 21.6%. The coincidence timing resolution for the entire system is 8.1 ns. A line bar phantom was imaged and images were reconstructed using the focal plane tomography algorithm. A 4 mm projection image resolution was measured based on profiles taken through the line bar phantom images. The goal of the maxPET system will be to aid in breast cancer patient management by assisting in imaging women with dense, fibro-glandular breasts, detecting axillary lymph node metastases without surgery, monitoring chemotherapy effectiveness and assisting in visualization of recurrence and tumoral boundaries.

Success in large high-technology projects: What really works?

NASA Astrophysics Data System (ADS)

Crosby, P.

2014-08-01

Despite a plethora of tools, technologies and management systems, successful execution of big science and engineering projects remains problematic. The sheer scale of globally funded projects such as the Large Hadron Collider and the Square Kilometre Array telescope means that lack of project success can impact both on national budgets, and collaborative reputations. In this paper, I explore data from contemporary literature alongside field research from several current high-technology projects in Europe and Australia, and reveal common `pressure points' that are shown to be key influencers of project control and success. I discuss the how mega-science projects sit between being merely complicated, and chaotic, and explain the importance of understanding multiple dimensions of project complexity. Project manager/leader traits are briefly discussed, including capability to govern and control such enterprises. Project structures are examined, including the challenge of collaborations. I show that early attention to building project resilience, curbing optimism, and risk alertness can help prepare large high-tech projects against threats, and why project managers need to understand aspects of `the silent power of time'. Mission assurance is advanced as a critical success function, alongside the deployment of task forces and new combinations of contingency plans. I argue for increased project control through industrial-style project reviews, and show how post-project reviews are an under-used, yet invaluable avenue of personal and organisational improvement. Lastly, I discuss the avoidance of project amnesia through effective capture of project knowledge, and transfer of lessons-learned to subsequent programs and projects.

Straw man trade between multi-junction, gallium arsenide, and silicon solar cells

NASA Technical Reports Server (NTRS)

Gaddy, Edward M.

1995-01-01

Multi-junction (MJ), gallium arsenide (GaAs), and silicon (Si) solar cells have respective test efficiencies of approximately 24%, 18.5% and 14.8%. Multi-junction and gallium arsenide solar cells weigh more than silicon solar cells and cost approximately five times as much per unit power at the cell level. A straw man trade is performed for the TRMM spacecraft to determine which of these cell types would have offered an overall performance and price advantage to the spacecraft. A straw man trade is also performed for the multi-junction cells under the assumption that they will cost over ten times that of silicon cells at the cell level. The trade shows that the TRMM project, less the cost of the instrument, ground systems and mission operations, would spend approximately $552 thousand dollars per kilogram to launch and service science in the case of the spacecraft equipped with silicon solar cells. If these cells are changed out for gallium arsenide solar cells, an additional 31 kilograms of science can be launched and serviced at a price of approximately $90 thousand per kilogram. The weight reduction is shown to derive from the smaller area of the array and hence reductions in the weight of the array substrate and supporting structure. If the silicon solar cells are changed out for multi-junction solar cells, an additional 45 kilograms of science above the silicon base line can be launched and serviced at a price of approximately $58 thousand per kilogram. The trade shows that even if the multi-junction arrays are priced over ten times that of silicon cells, a price that is much higher than projected, that the additional 45 kilograms of science are launched and serviced at $182 thousand per kilogram. This is still much less than original $552 thousand per kilogram to launch and service the science. Data and qualitative factors are presented to show that these figures are subject to a great deal of uncertainty. Nonetheless, the benefit of the higher efficiency solar cells for TRMM is far greater than the uncertainties in the analysis.

Risk Reduction for Use of Complex Devices in Space Projects

NASA Technical Reports Server (NTRS)

Berg, Melanie; Poivey, Christian; Friendlich, Mark; Petrick, Dave; LaBel, Kenneth; Stansberry, Scott

2007-01-01

We present guidel!nes to reduce risk to an acceptable level when using complex devices in space applications. Application to Virtex 4 Field Programmable Gate Array (FPGA) on Express Logistic Carrier (ELC) project is presented.

SMEX-Lite Modular Solar Array Architecture

NASA Technical Reports Server (NTRS)

Lyons, John

2002-01-01

For the most part, Goddard solar arrays have been custom designs that are unique to each mission. The solar panel design has been frozen prior to issuing an RFP for their procurement. There has typically been 6-9 months between RFP release and contract award, followed by an additional 24 months for performance of the contract. For Small Explorer (SMEX) missions, with three years between mission definition and launch, this has been a significant problem. The SMEX solar panels have been sufficiently small that the contract performance period has been reduced to 12-15 months. The bulk of this time is used up in the final design definition and fabrication of flight solar cell assemblies. Even so, it has been virtually impossible to have the spacecraft design at a level of maturity sufficient to freeze the solar panel geometry and release the RFP in time to avoid schedule problems with integrating the solar panels to the spacecraft. With that in mind, the SMEX-Lite project team developed a modular architecture for the assembly of solar arrays to greatly reduce the cost and schedule associated with the development of a mission- specific solar array. In the modular architecture, solar cells are fabricated onto small substrate panels. This modular panel (approximately 8.5" x 17" in this case) becomes the building block for constructing solar arrays for multiple missions with varying power requirements and geometrical arrangements. The mechanical framework that holds these modules together as a solar array is the only mission-unique design, changing in size and shape as required for each mission. There are several advantages to this approach. First, the typical solar array development cycle requires a mission unique design, procurement, and qualification including a custom qualification panel. With the modular architecture, a single qualification of the SMEX-Lite modules and the associated mechanical framework in a typical configuration provided a qualification by similarity to multiple missions. It then becomes possible to procure solar array modules in advance of mission definition and respond quickly and inexpensively to a selected mission's unique requirements. The solar array modular architecture allows the procurement of solar array modules before the array geometry has been frozen. This reduces the effect of procurement lead-time on the mission integration and test flow by as much as 50%. Second, by spreading the non-recurring costs over multiple missions, the cost per unit area is also reduced. In the case of the SMEX-Lite procurement, this reduction was by about one third of the cost per unit area compared to previous SMEX mission-unique procurements. Third, the modular architecture greatly facilitates the infusion of new solar cell technologies into flight programs as these technologies become available. New solar cell technologies need only be fabricated onto a standard-sized module to be incorporated into the next available mission. The modular solar array can be flown in a mixed configuration with some new and some standard cell technologies. Since each module has its own wiring terminals, the array can be arranged as desired electrically with little impact to cost and schedule. The solar array modular architecture does impose some additional constraints on systems and subsystem engineers. First, they must work with discrete solar array modules rather than size the array to fit exactly within an available envelope. The array area is constrained to an integer multiple of the module area. Second, the modular design is optimized for space radiation and thermal environments not greatly different from a typical SMEX LEO environment. For example, a mission with a highly elliptical orbit (e.g., Polar, SMEX/FAST) would require thicker coverglasses to protect the solar cells from the more intense radiation environment.

Radio Continuum Surveys with Square Kilometre Array Pathfinders

NASA Astrophysics Data System (ADS)

Norris, Ray P.; Afonso, J.; Bacon, D.; Beck, Rainer; Bell, Martin; Beswick, R. J.; Best, Philip; Bhatnagar, Sanjay; Bonafede, Annalisa; Brunetti, Gianfranco; Budavári, Tamás; Cassano, Rossella; Condon, J. J.; Cress, Catherine; Dabbech, Arwa; Feain, I.; Fender, Rob; Ferrari, Chiara; Gaensler, B. M.; Giovannini, G.; Haverkorn, Marijke; Heald, George; Van der Heyden, Kurt; Hopkins, A. M.; Jarvis, M.; Johnston-Hollitt, Melanie; Kothes, Roland; Van Langevelde, Huib; Lazio, Joseph; Mao, Minnie Y.; Martínez-Sansigre, Alejo; Mary, David; Mcalpine, Kim; Middelberg, E.; Murphy, Eric; Padovani, P.; Paragi, Zsolt; Prandoni, I.; Raccanelli, A.; Rigby, Emma; Roseboom, I. G.; Röttgering, H.; Sabater, Jose; Salvato, Mara; Scaife, Anna M. M.; Schilizzi, Richard; Seymour, N.; Smith, Dan J. B.; Umana, Grazia; Zhao, G.-B.; Zinn, Peter-Christian

2013-03-01

In the lead-up to the Square Kilometre Array (SKA) project, several next-generation radio telescopes and upgrades are already being built around the world. These include APERTIF (The Netherlands), ASKAP (Australia), e-MERLIN (UK), VLA (USA), e-EVN (based in Europe), LOFAR (The Netherlands), MeerKAT (South Africa), and the Murchison Widefield Array. Each of these new instruments has different strengths, and coordination of surveys between them can help maximise the science from each of them. A radio continuum survey is being planned on each of them with the primary science objective of understanding the formation and evolution of galaxies over cosmic time, and the cosmological parameters and large-scale structures which drive it. In pursuit of this objective, the different teams are developing a variety of new techniques, and refining existing ones. To achieve these exciting scientific goals, many technical challenges must be addressed by the survey instruments. Given the limited resources of the global radio-astronomical community, it is essential that we pool our skills and knowledge. We do not have sufficient resources to enjoy the luxury of re-inventing wheels. We face significant challenges in calibration, imaging, source extraction and measurement, classification and cross-identification, redshift determination, stacking, and data-intensive research. As these instruments extend the observational parameters, we will face further unexpected challenges in calibration, imaging, and interpretation. If we are to realise the full scientific potential of these expensive instruments, it is essential that we devote enough resources and careful study to understanding the instrumental effects and how they will affect the data. We have established an SKA Radio Continuum Survey working group, whose prime role is to maximise science from these instruments by ensuring we share resources and expertise across the projects. Here we describe these projects, their science goals, and the technical challenges which are being addressed to maximise the science return.

The design of the local monitor and control system of SKA dishes

NASA Astrophysics Data System (ADS)

Schillirò, F.; Baldini, V.; Becciani, U.; Cirami, R.; Costa, A.; Ingallinera, A.; Marassi, A.; Nicotra, G.; Nocita, C.; Riggi, S.; Trigilio, C.

2016-08-01

The Square Kilometer Array (SKA) project aims at building the world's largest radio observatory to observe the sky with unprecedented sensitivity and collecting area. In the first phase of the project (SKA1), an array of dishes, SKA1-MID, will be built in South Africa. It will consist of 133 15m-dishes, which will include the MeerKAT array, for the 0.350-20 GHz frequency band observations. Each antenna will be provided with a local monitor and control system (LMC), enabling operations both to the Telescope Manager remote system, and to the engineers and maintenance staff; it provides different environment for the telescope control (positioning, pointing, observational bands), metadata collection for monitoring and database storaging, operational modes and functional states management for all the telescope capabilities. In this paper we present the LMC software architecture designed for the detailed design phase (DD), where we describe functional and physical interfaces with monitored and controlled sub-elements, and highlight the data flow between each LMC modules and its sub-element controllers from one side, and Telescope Manager on the other side. We also describe the complete Product Breakdown Structure (PBS) created in order to optimize resources allocation in terms of calculus and memory, able to perform required task for each element according to the proper requirements. Among them, time response and system reliability are the most important, considering the complexity of SKA dish network and its isolated placement. Performances obtained by software implementation using TANGO framework will be discussed, matching them with technical requirements derived by SKA science drivers.

Electrostatic artificial eyelid actuator as an analog micromirror device

NASA Astrophysics Data System (ADS)

Goodwin, Scott H.; Dausch, David E.; Solomon, Steven L.; Lamvik, Michael K.

2005-05-01

An electrostatic MEMS actuator is described for use as an analog micromirror device (AMD) for high performance, broadband, hardware-in-the-loop (HWIL) scene generation. Current state-of-the-art technology is based on resistively heated pixel arrays. As these arrays drive to the higher scene temperatures required by missile defense scenarios, the power required to drive the large format resistive arrays will ultimately become prohibitive. Existing digital micromirrors (DMD) are, in principle, capable of generating the required scene irradiances, but suffer from limited dynamic range, resolution and flicker effects. An AMD would be free of these limitations, and so represents a viable alternative for high performance UV/VIS/IR scene generation. An electrostatic flexible film actuator technology, developed for use as "artificial eyelid" shutters for focal plane sensors to protect against damaging radiation, is suitable as an AMD for analog control of projection irradiance. In shutter applications, the artificial eyelid actuator contained radius of curvature as low as 25um and operated at high voltage (>200V). Recent testing suggests that these devices are capable of analog operation as reflective microcantilever mirrors appropriate for scene projector systems. In this case, the device would possess larger radius and operate at lower voltages (20-50V). Additionally, frame rates have been measured at greater than 5kHz for continuous operation. The paper will describe the artificial eyelid technology, preliminary measurements of analog test pixels, and design aspects related to application for scene projection systems. We believe this technology will enable AMD projectors with at least 5122 spatial resolution, non-temporally-modulated output, and pixel response times of <1.25ms.

Evaluation of whole genome amplified DNA to decrease material expenditure and increase quality.

PubMed

Bækvad-Hansen, Marie; Bybjerg-Grauholm, Jonas; Poulsen, Jesper B; Hansen, Christine S; Hougaard, David M; Hollegaard, Mads V

2017-06-01

The overall aim of this study is to evaluate whole genome amplification of DNA extracted from dried blood spot samples. We wish to explore ways of optimizing the amplification process, while decreasing the amount of input material and inherently the cost. Our primary focus of optimization is on the amount of input material, the amplification reaction volume, the number of replicates and amplification time and temperature. Increasing the quality of the amplified DNA and the subsequent results of array genotyping is a secondary aim of this project. This study is based on DNA extracted from dried blood spot samples. The extracted DNA was subsequently whole genome amplified using the REPLIg kit and genotyped on the PsychArray BeadChip (assessing > 570,000 SNPs genome wide). We used Genome Studio to evaluate the quality of the genotype data by call rates and log R ratios. The whole genome amplification process is robust and does not vary between replicates. Altering amplification time, temperature or number of replicates did not affect our results. We found that spot size i.e. amount of input material could be reduced without compromising the quality of the array genotyping data. We also showed that whole genome amplification reaction volumes can be reduced by a factor of 4, without compromising the DNA quality. Whole genome amplified DNA samples from dried blood spots is well suited for array genotyping and produces robust and reliable genotype data. However, the amplification process introduces additional noise to the data, making detection of structural variants such as copy number variants difficult. With this study, we explore ways of optimizing the amplification protocol in order to reduce noise and increase data quality. We found, that the amplification process was very robust, and that changes in amplification time or temperature did not alter the genotyping calls or quality of the array data. Adding additional replicates of each sample also lead to insignificant changes in the array data. Thus, the amount of noise introduced by the amplification process was consistent regardless of changes made to the amplification protocol. We also explored ways of decreasing material expenditure by reducing the spot size or the amplification reaction volume. The reduction did not affect the quality of the genotyping data.

Photovoltaic Test and Demonstration Project. [for solar cell power systems

NASA Technical Reports Server (NTRS)

Forestieri, A. F.; Brandhorst, H. W., Jr.; Deyo, J. N.

1976-01-01

The Photovoltaic Test and Demonstration Project was initiated by NASA in June, 1975, to develop economically feasible photovoltaic power systems suitable for a variety of terrestrial applications. Objectives include the determination of operating characteristic and lifetimes of a variety of solar cell systems and components and development of methodology and techniques for accurate measurements of solar cell and array performance and diagnostic measurements for solar power systems. Initial work will be concerned with residential applications, with testing of the first prototype system scheduled for June, 1976. An outdoor 10 kW array for testing solar power systems is under construction.

SERT D spacecraft study. [project planning and objectives

NASA Technical Reports Server (NTRS)

1974-01-01

The SERT D (Space Electric Rocket Test - D) study defines a possible spacecraft project that would demonstrate the use of electric ion thrusters for long-term (5 yr) station keeping and attitude control of a synchronous orbit satellite. Other mission objectives included in the study were: station walking to satellite rendezvous and inspection, use of low cost attitude sensing system, use of an advanced solar array orientation and slip ring system, and an ion thruster integrated directly with a solar array power source. The SERT D spacecraft, if launched, will become SERT 3 the third space electric thruster test.

Optics Design for the U.S. SKA Technology Development Project Design Verification Antenna

NASA Technical Reports Server (NTRS)

Imbriale, W. A.; Baker, L.; Cortes-Medellin, G.

2012-01-01

The U.S. design concept for the Square Kilometer Array (SKA) program is based on utilizing a large number of 15 meter dish antennas. The Technology Development Project (TDP) is planning to design and build the first of these antennas to provide a demonstration of the technology and a solid base on which to estimate costs. This paper describes the performance of the selected optics design. It is a dual-shaped offset Gregorian design with a feed indexer that can accommodate corrugated horns, wide band single pixel feeds or phased array feeds.

Immersion probe arrays for rapid pipeline weld inspection

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

Lebsack, S.; Heckhauser, H.

In 1992, F.H. Gottfeld, Herne, Germany, a member of the SGA Group (Societe Generale de Surveillance) and Krautkramer Branson, Koin, undertook production of a rapid automated ultrasonic testing (UT) system to inspect manually and machine welded pipeline girth welds. The result of the project is a system called MIPA, or multiple immersion probe array. The advantages of using UT to detect certain weld defects have been realized for many years, however for some applications the time required for UT has been a limiting factor. Where time has not been a factor, automated ultrasonic technology has advanced a reliable solution tomore » many inspection problems across a broad industrial base. The recent past has seen the entrance of automated ultrasonic technology into the harsh and demanding environment of pipelay operations, However, the use of these systems has been focused on automated welding processes. Their effectiveness for manual pipeline welding inspection is contested. This is due to the infinite variability of the joint alignment and shape that is unavoidable even when highly skilled welders are used.« less

Using EarthScope magnetotelluric data to improve the resilience of the US power grid: rapid predictions of geomagnetically induced currents

NASA Astrophysics Data System (ADS)

Schultz, A.; Bonner, L. R., IV

2016-12-01

Existing methods to predict Geomagnetically Induced Currents (GICs) in power grids, such as the North American Electric Reliability Corporation standard adopted by the power industry, require explicit knowledge of the electrical resistivity structure of the crust and mantle to solve for ground level electric fields along transmission lines. The current standard is to apply regional 1-D resistivity models to this problem, which facilitates rapid solution of the governing equations. The systematic mapping of continental resistivity structure from projects such as EarthScope reveals several orders of magnitude of lateral variations in resistivity on local, regional and continental scales, resulting in electric field intensifications relative to existing 1-D solutions that can impact GICs to first order. The computational burden on the ground resistivity/GIC problem of coupled 3-D solutions inhibits the prediction of GICs in a timeframe useful to protecting power grids. In this work we reduce the problem to applying a set of filters, recognizing that the magnetotelluric impedance tensors implicitly contain all known information about the resistivity structure beneath a given site, and thus provides the required relationship between electric and magnetic fields at each site. We project real-time magnetic field data from distant magnetic observatories through a robustly calculated multivariate transfer function to locations where magnetotelluric impedance tensors had previously been obtained. This provides a real-time prediction of the magnetic field at each of those points. We then project the predicted magnetic fields through the impedance tensors to obtain predictions of electric fields induced at ground level. Thus, electric field predictions can be generated in real-time for an entire array from real-time observatory data, then interpolated onto points representing a power transmission line contained within the array to produce a combined electric field prediction necessary for GIC prediction along that line. This method produces more accurate predictions of ground electric fields in conductively heterogeneous areas that are not limited by distance from the nearest observatory, while still retaining comparable computational speeds as existing methods.

Infrasonic Monitoring Network on the Big Island of Hawaii

NASA Astrophysics Data System (ADS)

Thelen, Weston; Garces, Milton; Cooper, Jennifer; Badger, Nickles; Perttu, Anna; Williams, Brian

2013-04-01

The USGS Hawaiian Volcano Observatory (HVO) with the participation of the University of Hawaii Infrasound Lab (ISLA) installed three new permanent infrasound arrays on the south half of the Island of Hawaii. Together with three existing permanent arrays maintained by ISLA, the current infrasound network around Kīlauea and Mauna Loa volcanoes is one of the most advanced of any volcano in the world. Open-vent volcanoes such as Kīlauea are particularly good infrasound emitters as lava spattering and unsteady gas release is common. The network was designed with two main goals in mind: 1) to monitor and study the infrasound sources associated with the ongoing Pu`u `Ō`ō and Halema'u'mau eruption, and 2) to detect in near real-time new eruptions at Mauna Loa or Kīlauea volcanoes. Each HVO array consists of 4 sensors, which form an equilateral triangle ~100 m on a side surrounding a central sensor. Three other permanent arrays maintained by ISLA (I59US, MENE, KHLU) have been operational since 2000, 2006, and 2009, respectively, and consist of a combination of Chaparral 25 and 50 sensors. Each infrasound instrument within the HVO arrays is built around an low- cost AllSensor MEMS sensor, which has higher noise characteristics than a Chaparral 25, but similar frequency response. ISLA also operates stations on Maui and Kauai that provide --statewide coverage. Since the full network has been established, we have recorded several infrasound signals including infrasonic tremor from Halema`uma`u, collapses from the craters of Halema`uma`u and Pu`u `Ō`ō, and other natural and anthropogenic infrasound from diverse sources on- island, offshore, and aloft. Future developments will include real-time detection, location, and identification of infrasonic signals for eruption notification. We hope to increase public awareness of volcanic infrasound by posting real-time locations on an interactive display, similar to how seismicity is currently reported. MENE data is presently available, and the HVO infrasound data should be available for research projects through the IRIS Data Management Center beginning in March 2013.

Phase 2 of the array automated assembly task for the low cost solar array project

NASA Technical Reports Server (NTRS)

Campbell, R. B.; Davis, J. R.; Ostroski, J. W.; Rai-Choudhury, P.; Rohatgi, A.; Seman, E. J.; Stapleton, R. E.

1979-01-01

The process sequence for the fabrication of dendritic web silicon into solar panels was modified to include aluminum back surface field formation. Plasma etching was found to be a feasible technique for pre-diffusion cleaning of the web. Several contacting systems were studied. The total plated Pd-Ni system was not compatible with the process sequence; however, the evaporated TiPd-electroplated Cu system was shown stable under life testing. Ultrasonic bonding parameters were determined for various interconnect and contact metals but the yield of the process was not sufficiently high to use for module fabrication at this time. Over 400 solar cells were fabricated according to the modified sequence. No sub-process incompatibility was seen. These cells were used to fabricate four demonstration modules. A cost analysis of the modified process sequence resulted in a selling price of $0.75/peak watt.

Development of a General-Purpose Analysis System Based on a Programmable Fluid Processor Final Report CRADA No. TC-2027-01

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

McConaghy, C. F.; Gascoyne, P. R.

The purpose ofthis project was to develop a general-purpose analysis system based on a programmable fluid processor (PFP). The PFP is an array of electrodes surrounded by fluid reservoirs and injectors. Injected droplets of various reagents are manjpulated and combined on the array by Dielectrophoretic (DEP) forces. The goal was to create a small handheld device that could accomplish the tasks currently undertaken by much larger, time consuming, manual manipulation in the lab. The entire effo1t was funded by DARPA under the Bio-Flips program. MD Anderson Cancer Center was the PI for the DARPA effort. The Bio-Flips program was amore » 3- year program that ran from September 2000 to September 2003. The CRADA was somewhat behind the Bi-Flips program running from June 2001 to June 2004 with a no cost extension to September 2004.« less

Universal lab on a smartphone: a research of TiOPc thin film as a light dependence electrode

NASA Astrophysics Data System (ADS)

Lin, PoHan; Hsu, Y. H.; Lee, C. K.

2014-02-01

In this paper, we study the photoconductivity of a polymer-based TiOPc (Titanium Oxide Phthalocyanine) thin-film for the development of a multi-opto-piezoelectric-valve-array. Using a polymer-based TiOPc thin film to serve as the electrode and a structural layer of a piezoelectric polymer, P(VDF-TrFE) poly[(vinylidenefluoride-co-trifluoroethylene], an optical control valve-array could be developed for manipulating multiple microdroplets for the application of digital microfluidic. In this ongoing project, the dependency of the light intensity, thickness, and composition of spin-coated polymer-based TiOPc thin-film was studied. The experimental finding suggested that a 14 to 55 times resistivity change could be achieved by controlling the film thickness to be between 0.9 μm and 1.5 μm with TiOPc concentration of 20% and 30% w/w compositions.

The MicroArray Quality Control (MAQC)-II study of common practices for the development and validation of microarray-based predictive models

EPA Science Inventory

The second phase of the MicroArray Quality Control (MAQC-II) project evaluated common practices for developing and validating microarray-based models aimed at predicting toxicological and clinical endpoints. Thirty-six teams developed classifiers for 13 endpoints - some easy, som...

Solar lunar power

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Landis, Geoffrey A.

1994-01-01

Current and projected technology is assessed for photovoltaic power for a lunar base. The following topics are discussed: requirements for power during the lunar day and night; solar cell efficiencies, specific power, temperature sensitivity, and availability; storage options for the lunar night; array and system integration; the potential for in situ production of photovoltaic arrays and storage medium.

Study of one- and two-dimensional filtering and deconvolution algorithms for a streaming array computer

NASA Technical Reports Server (NTRS)

Ioup, G. E.

1985-01-01

Appendix 5 of the Study of One- and Two-Dimensional Filtering and Deconvolution Algorithms for a Streaming Array Computer includes a resume of the professional background of the Principal Investigator on the project, lists of this publications and research papers, graduate thesis supervised, and grants received.

The Missouri Ozark Forest Ecosystem Project: past, present, and future

Treesearch

Brian L. Brookshire; Randy Jensen; Daniel C. Dey

1997-01-01

In 1989, the Missouri Department of Conservation initiated a research project to examine the impacts of forest management practices on multiple ecosystem components. The Missouri Ozark Forest Ecosystem Project (MOFEP) is a landscape experiment comparing the impacts of even-aged management, uneven-aged management, and no harvesting on a wide array of ecosystem...

Progress Report 18 for the Period February to July 1981 and Proceeidngs of the 18th Project Integration Meeting

NASA Technical Reports Server (NTRS)

1981-01-01

Progress in the low cost solar array project during the period February to July 1981 is reported. Included are: (1) project analysis and integration; (2) technology development in silicon material, large area silicon sheer and encapsulation; (3) process development; (4) engineering, and operations.

MIRAGE: developments in IRSP systems, RIIC design, emitter fabrication, and performance

NASA Astrophysics Data System (ADS)

Bryant, Paul; Oleson, Jim; James, Jay; McHugh, Steve; Lannon, John; Vellenga, David; Goodwin, Scott; Huffman, Alan; Solomon, Steve; Goldsmith, George C., II

2005-05-01

SBIR's family of MIRAGE infrared scene projection systems is undergoing significant growth and expansion. The first two lots of production IR emitters have completed fabrication at Microelectronics Center of North Carolina/Research and Development Institute (MCNC-RDI), and the next round(s) of emitter production has begun. These latest emitter arrays support programs such as Large Format Resistive Array (LFRA), Optimized Array for Space-based Infrared Simulation (OASIS), MIRAGE 1.5, and MIRAGE II. We present the latest performance data on emitters fabricated at MCNC-RDI, plus integrated system performance on recently completed IRSP systems. Teamed with FLIR Systems/Indigo Operations, SBIR and the Tri-Services IRSP Working Group have completed development of the CMOS Read-In Integrated Circuit (RIIC) portion of the Wide Format Resistive Array (WFRA) program-to extend LFRA performance to a 768 x 1536 "wide screen" projection configuration. WFRA RIIC architecture and performance is presented. Finally, we summarize development of the LFRA Digital Emitter Engine (DEE) and OASIS cryogenic package assemblies, the next-generation Command & Control Electronics (C&CE).

The Air Force concentrating photovoltaic array program

NASA Technical Reports Server (NTRS)

Geis, Jack W.

1987-01-01

A summary is given of Air Force solar concentrator projects beginning with the Rockwell International study program in 1977. The Satellite Materials Hardening Programs (SMATH) explored and developed techniques for hardening planar solar cell array power systems to the combined nuclear and laser radiation threat environments. A portion of program dollars was devoted to developing a preliminary design for a hardened solar concentrator. The results of the Survivable Concentrating Photovoltaic Array (SCOPA) program, and the design, fabrication and flight qualification of a hardened concentrator panel are discussed.

Observations of Seafloor Ambient Noise with an Ocean Bottom Seismometer Array

DTIC Science & Technology

1989-12-01

April and May of 1987. The array was situated near Deep Sea Drilling Project (DSDP) Hole 469 at a depth of 3.8 km (Figure 2.1). The area is a 400 m...any array processing method can be gauged by its resolution, bias 34 and stability. These quantities are sensitive to errors such as uncertain...Spectral Ocean Wave Model, Bull. Amer. Meteor. Soc, 67,498-512,1986. Cox, C. S., T. Deaton, and S. C. Webb, A deep-sea differential pressure gauge

Array Automated Assembly Task Low Cost Silicon Solar Array Project, Phase 2

NASA Technical Reports Server (NTRS)

Rhee, S. S.; Jones, G. T.; Allison, K. L.

1978-01-01

Progress in the development of solar cells and module process steps for low-cost solar arrays is reported. Specific topics covered include: (1) a system to automatically measure solar cell electrical performance parameters; (2) automation of wafer surface preparation, printing, and plating; (3) laser inspection of mechanical defects of solar cells; and (4) a silicon antireflection coating system. Two solar cell process steps, laser trimming and holing automation and spray-on dopant junction formation, are described.

Seafloor horizontal positioning from a continuously operating buoy-based GPS-acoustic array

NASA Astrophysics Data System (ADS)

Chadwell, C. D.; Brown, K. M.; Tryon, M. D.; Send, U.

2009-12-01

Seafloor horizontal positions in a global frame were estimated daily from an autonomous buoy operating continuously over several months. The buoy (GEOCE) was moored offshore San Diego in 100-m-deep waters above an array of 4 seafloor transponders. Dual-frequency GPS data were collected at 1-Hz at a main antenna on the buoy and at 3 shore stations to provide continuous 2-3 cm positions of the buoy main antenna. Two single-frequency antennas on the buoy along with the main antenna were used to estimate the buoy attitude and short-term velocity. At one minute intervals the two-way acoustic travel time was measured between the buoy and transponders. During this few second span when transmitting and receiving acoustic signals, 10-Hz attitude and velocity were collected to locate the position of the transducer mounted approximately 2 m below the water line. The GPS and acoustic data were recorded internally and transmitted to shore over a cell-phone link and/or a wireless Ethernet. GPS data were combined with the acoustic data to estimate the array location at 1 minute intervals. The 1-minute positions are combined to provide a daily estimate of the array position. The buoy is autonomous, solar-powered and in addition to the GPS and acoustic data collects air pressure, temperature, wind speed/direction as well as water level at the surface and conductivity and temperature along the mooring line from near the sea surface to just above the sea floor. Here we report results from the horizontal positioning effort from Phase I of the project in shallow waters. The project also includes a vertical deformation sensor and physical oceanographic monitoring. A deep water (nominally 1000 m) test is planned for 2010. This work is supported by NSF-OCE-0551363 of the Ocean Technology and Interdisciplinary Coordination Program.

The Allen Telescope Array

NASA Astrophysics Data System (ADS)

DeBoer, David R.; Welch, William J.; Dreher, John; Tarter, Jill; Blitz, Leo; Davis, Michael; Fleming, Matt; Bock, Douglas; Bower, Geoffrey; Lugten, John; Girmay-Keleta, G.; D'Addario, Larry R.; Harp, Gerry R.; Ackermann, Rob; Weinreb, Sander; Engargiola, Greg; Thornton, Doug; Wadefalk, Niklas

2004-10-01

The Allen Telescope Array, originally called the One Hectare Telescope (1hT) [1] will be a large array radio telescope whose novel characteristics will be a wide field of view (3.5 deg-GHz HPBW), continuous frequency coverage of 0.5 - 11 GHz, four dual-linear polarization output bands of 100 MHz each, four beams in each band, two 100 MHz spectral correlators for two of the bands, and hardware for RFI mitigation built in. Its scientific motivation is for deep SETI searches and, at the same time, a variety of other radio astronomy projects, including transient (e.g. pulsar) studies, HI mapping of the Milky Way and nearby galaxies, Zeeman studies of the galactic magnetic field in a number of transitions, mapping of long chain molecules in molecular clouds, mapping of the decrement in the cosmic background radiation toward galaxy clusters, and observation of HI absorption toward quasars at redshifts up to z=2. The array is planned for 350 6.1-meter dishes giving a physical collecting area of about 10,000 square meters. The large number of components reduces the price with economies of scale. The front end receiver is a single cryogenically cooled MIMIC Low Noise Amplifier covering the whole band. The feed is a wide-band log periodic feed of novel design, and the reflector system is an offset Gregorian for minimum sidelobes and spillover. All preliminary and critical design reviews have been completed. Three complete antennas with feeds and receivers are under test, and an array of 33 antennas is under construction at the Hat Creek Radio Observatory for the end of 2004. The present plan is to have a total of about 200 antennas completed by the summer of 2006 and the balance of the array finished before the end of the decade.

Imaging Crustal Structure with Waveform and HV Ratio of Body-wave Receiver Function

NASA Astrophysics Data System (ADS)

Chong, J.; Chu, R.; Ni, S.; Meng, Q.; Guo, A.

2017-12-01

It is known that receiver function has less constraint on the absolute velocity, and joint inversion of receiver function and surface wave dispersion has been widely applied to reduce the non-uniqueness of velocity and interface depth. However, some studies indicate that the receiver function itself is capable for determining the absolute shear wave velocity. In this study, we propose to measure the receiver function HV ratio which takes advantage of the amplitude information of the radial and vertical receiver functions to constrain the shear-wave velocity. Numerical analysis indicates that the receiver function HV ratio is sensitive to the average shear wave velocity in the depth range it samples, and can help to reduce the non-uniqueness of receiver function waveform inversion. A joint inversion scheme has been developed, and both synthetic tests and real data application proved the feasibility of the joint inversion. The method has been applied to the dense seismic array of ChinArray program in SE Tibet during the time period from August 2011 to August 2012 in SE Tibet (ChinArray-Himalaya, 2011). The measurements of receiver function HV ratio reveals the lateral variation of the tectonics in of the study region. And main features of the velocity structure imagined by the new joint inversion method are consistent with previous studies. KEYWORDS: receiver function HV ratio, receiver function waveform inversion, crustal structure ReferenceChinArray-Himalaya. 2011. China Seismic Array waveform data of Himalaya Project. Institute of Geophysics, China Earthquake Administration. doi:10.12001/ChinArray.Data. Himalaya. Jiajun Chong, Risheng Chu*, Sidao Ni, Qingjun Meng, Aizhi Guo, 2017. Receiver Function HV Ratio, a New Measurement for Reducing Non-uniqueness of Receiver Function Waveform Inversion. (under revision)

A methodological proposal for the development of an HPC-based antenna array scheduler

NASA Astrophysics Data System (ADS)

Bonvallet, Roberto; Hoffstadt, Arturo; Herrera, Diego; López, Daniela; Gregorio, Rodrigo; Almuna, Manuel; Hiriart, Rafael; Solar, Mauricio

2010-07-01

As new astronomy projects choose interferometry to improve angular resolution and to minimize costs, preparing and optimizing schedules for an antenna array becomes an increasingly critical task. This problem shares similarities with the job-shop problem, which is known to be a NP-hard problem, making a complete approach infeasible. In the case of ALMA, 18000 projects per season are expected, and the best schedule must be found in the order of minutes. The problem imposes severe difficulties: the large domain of observation projects to be taken into account; a complex objective function, composed of several abstract, environmental, and hardware constraints; the number of restrictions imposed and the dynamic nature of the problem, as weather is an ever-changing variable. A solution can benefit from the use of High-Performance Computing for the final implementation to be deployed, but also for the development process. Our research group proposes the use of both metaheuristic search and statistical learning algorithms, in order to create schedules in a reasonable time. How these techniques will be applied is yet to be determined as part of the ongoing research. Several algorithms need to be implemented, tested and evaluated by the team. This work presents the methodology proposed to lead the development of the scheduler. The basic functionality is encapsulated into software components implemented on parallel architectures. These components expose a domain-level interface to the researchers, enabling then to develop early prototypes for evaluating and comparing their proposed techniques.

Multibeam Phased Array Antennas

NASA Technical Reports Server (NTRS)

Popovic, Zoya; Romisch, Stefania; Rondineau, Sebastien

2004-01-01

In this study, a new architecture for Ka-band multi-beam arrays was developed and demonstrated experimentally. The goal of the investigation was to demonstrate a new architecture that has the potential of reducing the cost as compared to standard expensive phased array technology. The goals of this specific part of the project, as stated in the yearly statement of work in the original proposal are: 1. Investigate bounds on performance of multi-beam lens arrays in terms of beamwidths, volume (size), isolation between beams, number of simultaneous beams, etc. 2. Design a small-scale array to demonstrate the principle. The array will be designed for operation around 3OGHz (Ka-band), with two 10-degree beamwidth beams. 3. Investigate most appropriate way to accomplish fine-tuning of the beam pointing within 5 degrees around the main beam pointing angle.

Engineering Technical Support Center Annual Report Fiscal Year 2016

EPA Science Inventory

This report highlights significant projects that the ETSC supported in fiscal year 2016. These projects have addressed an array of environmental scenarios, including, but not limited to remote mining contamination, expansive landfill waste, cumulative impacts from multiple contam...

Robustness of a compact endfire personal audio system against scattering effects (L).

PubMed

Tu, Zhen; Lu, Jing; Qiu, Xiaojun

2016-10-01

Compact loudspeaker arrays have wide potential applications as portable personal audio systems that can project sound energy to specified regions. It is meaningful to investigate the scattering effects on the array performance since the scattering of the users' heads is inevitable in practice. A five-channel compact endfire array is established and the regularized acoustic contrast control method is evaluated for the scenarios of one moving listener and one listener fixed in the bright zone while another listener moves along the evaluation region. Both simulations and experiments verify that the scattering has limited influence on the directivity of the endfire array.

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

Meinke, Rainer B.; Goodzeit, Carl L.; Ball, Millicent J.

This research project advanced the development of reliable, cost-effective arrays of superconducting quadrupole magnets for use in multi-beam inertial fusion accelerators. The field in each array cell must be identical and meet stringent requirements for field quality and strength. An optimized compact array design using flat double-layer pancake coils was developed. Analytical studies of edge termination methods showed that it is feasible to meet the requirements for field uniformity in all cells and elimination of stray external field in several ways: active methods that involve placement of field compensating coils on the periphery of the array or a passive methodmore » that involves use of iron shielding.« less

BeadArray Expression Analysis Using Bioconductor

PubMed Central

Ritchie, Matthew E.; Dunning, Mark J.; Smith, Mike L.; Shi, Wei; Lynch, Andy G.

2011-01-01

Illumina whole-genome expression BeadArrays are a popular choice in gene profiling studies. Aside from the vendor-provided software tools for analyzing BeadArray expression data (GenomeStudio/BeadStudio), there exists a comprehensive set of open-source analysis tools in the Bioconductor project, many of which have been tailored to exploit the unique properties of this platform. In this article, we explore a number of these software packages and demonstrate how to perform a complete analysis of BeadArray data in various formats. The key steps of importing data, performing quality assessments, preprocessing, and annotation in the common setting of assessing differential expression in designed experiments will be covered. PMID:22144879

Modeling energy production of solar thermal systems and wind turbines for installation at corn ethanol plants

NASA Astrophysics Data System (ADS)

Ehrke, Elizabeth

Nearly every aspect of human existence relies on energy in some way. Most of this energy is currently derived from fossil fuel resources. Increasing energy demands coupled with environmental and national security concerns have facilitated the move towards renewable energy sources. Biofuels like corn ethanol are one of the ways the U.S. has significantly reduced petroleum consumption. However, the large energy requirement of corn ethanol limits the net benefit of the fuel. Using renewable energy sources to produce ethanol can greatly improve its economic and environmental benefits. The main purpose of this study was to model the useful energy received from a solar thermal array and a wind turbine at various locations to determine the feasibility of applying these technologies at ethanol plants around the country. The model calculates thermal energy received from a solar collector array and electricity generated by a wind turbine utilizing various input data to characterize the equipment. Project cost and energy rate inputs are used to evaluate the profitability of the solar array or wind turbine. The current state of the wind and solar markets were examined to give an accurate representation of the economics of each industry. Eighteen ethanol plant locations were evaluated for the viability of a solar thermal array and/or wind turbine. All ethanol plant locations have long payback periods for solar thermal arrays, but high natural gas prices significantly reduce this timeframe. Government incentives will be necessary for the economic feasibility of solar thermal arrays. Wind turbines can be very profitable for ethanol plants in the Midwest due to large wind resources. The profitability of wind power is sensitive to regional energy prices. However, government incentives for wind power do not significantly change the economic feasibility of a wind turbine. This model can be used by current or future ethanol facilities to investigate or begin the planning process for a solar thermal array or wind turbine. The model is meant to aide in the planning stages of a renewable energy project, and advanced investigation will be needed to move forward with that project.

Application of Reconfigurable Computing Technology to Multi-KiloHertz Micro-Laser Altimeter (MMLA) Data Processing

NASA Technical Reports Server (NTRS)

Powell, Wesley; Dabney, Philip; Hicks, Edward; Pinchinat, Maxime; Day, John H. (Technical Monitor)

2002-01-01

The Multi-KiloHertz Micro-Laser Altimeter (MMLA) is an aircraft based instrument developed by NASA Goddard Space Flight Center with several potential spaceflight applications. This presentation describes how reconfigurable computing technology was employed to perform MMLA signal extraction in real-time under realistic operating constraints. The MMLA is a "single-photon-counting" airborne laser altimeter that is used to measure land surface features such as topography and vegetation canopy height. This instrument has to date flown a number of times aboard the NASA P3 aircraft acquiring data at a number of sites in the Mid-Atlantic region. This instrument pulses a relatively low-powered laser at a very high rate (10 kHz) and then measures the time-of-flight of discrete returns from the target surface. The instrument then bins these measurements into a two-dimensional array (vertical height vs. horizontal ground track) and selects the most likely signal path through the array. Return data that does not correspond to the selected signal path are classified as noise returns and are then discarded. The MMLA signal extraction algorithm is very compute intensive in that a score must be computed for every possible path through the two dimensional array in order to select the most likely signal path. Given a typical array size with 50 x 6, up to 33 arrays must be processed per second. And for each of these arrays, roughly 12,000 individual paths must be scored. Furthermore, the number of paths increases exponentially with the horizontal size of the array, and linearly with the vertical size. Yet, increasing the horizontal and vertical sizes of the array offer science advantages such as improved range, resolution, and noise rejection. Due to the volume of return data and the compute intensive signal extraction algorithm, the existing PC-based MMLA data system has been unable to perform signal extraction in real-time unless the array is limited in size to one column, This limits the ability of the MMLA to operate in environments with sparse signal returns and a high number of noise return. However, under an IR&D project, an FPGA-based, reconfigurable computing data system has been developed that has been demonstrated to perform real-time signal extraction under realistic operating constraints. This reconfigurable data system is based on the commercially available Firebird Board from Annapolis Microsystems. This PCI board consists of a Xilinx Virtex 2000E FPGA along with 36 MB of SRAM arranged in five separately addressable banks. This board is housed in a rackmount PC with dual 850MHz Pentium processors running the Windows 2000 operating system. This data system performs all signal extraction in hardware on the Firebird, but also runs the existing "software based" signal extraction in tandem for comparison purposes. Using a relatively small amount of the Virtex XCV2000E resources, the reconfigurable data system has demonstrated to improve performance improvement over the existing software based data system by an order of magnitude. Performance could be further improved by employing parallelism. Ground testing and a preliminary engineering test flight aboard the NASA P3 has been performed, during which the reconfigurable data system has been demonstrated to match the results of the existing data system.

Development and Characterization of a Dither-Based Super-Resolution Reconstruction Method for Fiber Imaging Arrays

NASA Astrophysics Data System (ADS)

Languirand, Eric Robert

Chemical imaging is an important tool for providing insight into function, role, and spatial distribution of analytes. This thesis describes the use of imaging fiber bundles (IFB) for super-resolution reconstruction using surface enhanced Raman scattering (SERS) showing improvement in resolution with arrayed bundles for the first time. Additionally this thesis describes characteristics of the IFB with regards to cross-talk as a function of aperture size. The first part of this thesis characterizes the IFB for both tapered and untapered bundles in terms of cross-talk. Cross-talk is defined as the amount of light leaking from a central fiber element in the imaging fiber bundle to surrounding fiber elements. To make this measurement ubiquitous for all imaging bundles, quantum dots were employed. Untapered and tapered IFB possess cross-talk of 2% or less, with fiber elements down to 32nm. The second part of this thesis employs a super resolution reconstruction algorithm using projection onto convex sets for resolution improvement. When using IFB arrays, the point spread function (PSF) of the array can be known accurately if the fiber elements over fill the pixel detector array. Therefore, the use of the known PSF compared to a general blurring kernel was evaluated. Relative increases in resolution of 12% and 2% at the 95% confidence level are found, when compared to a reference image, for the general blurring kernel and PSF, respectively. The third part of this thesis shows for the first time the use of SERS with a dithered IFB array coupled with super-resolution reconstruction. The resolution improvement across a step-edge is shown to be approximately 20% when compared to a reference image. This provides an additional means of increasing the resolution of fiber bundles beyond that of just tapering. Furthermore, this provides a new avenue for nanoscale imaging using these bundles. Lastly, synthetic data with varying degrees of signal-to-noise (S/N) were employed to explore the relationship S/N has with the reconstruction process. It is generally shown that increasing the number images used in the reconstruction process and increasing the S/N will improve the reconstruction providing larger increases in resolution.

Detecting Moho Boundary under Taiwan with Wide-angle Data by Ray-tracing Method - The TAIGER Project

NASA Astrophysics Data System (ADS)

Kuo, Y. N.; Wang, C.; Okaya, D. A.

2009-12-01

Taiwan is located at the converging boundary of the Eurasian plate and the Philippine Sea plate, and is one of the most rapidly uplifting orogeny in the world. The geological structure is relatively complicated. There exist several models of tectonic collisions from the thin-skinned thrust, the lithospheric collision, to uplifting by buoyancy. The shape of Moho should be a key factor to evaluate these models. In this study, we try to detect the Moho beneath Taiwan using the newly collected wide-angle data from the Taiwan Integrated Geodynamic Research (TAIGER) project. The results could be of help to set up some constrains for the Taiwan tectonics. The TAIGER project is a collaboration between America and Taiwan. The land stations collected two parts of data (land and marine) generated by active sources. The land part was carried out in 2008/2~3, which created 6 kinds of data from explosion sources including: 1) 3 E-W wide-angle reflections of Texans arrays; 2) 2 N-S seismometer arrays; 3) the seismic networks of Central Weather Bureau(CWB) and Institute of Earth Science(IES) over the island; 4) a short array of RT130; 5) 2 short period OBS arrays in the Taiwan Strait; 6) 2 temporary seismic arrays in Fujan, mainland China. The marine part was carried out in 2009/4~6, which provided 4 kinds of data from air-gun sources including: 1) 4 wide-angle refractions of E-W RT130 arrays; 2) 2 N-S seismometer arrays; 3) the CWB network; 4) the broad band array in Taiwan for Seismology(BATS). In this study, we focus on analyzing the wide-angle data, which contain land explosion data, onshore-offshore data, OBS data and mainland data, especially concentrate on the line in the southern Taiwan (Transect T4). We make a summary of the TAIGER project and show several plots of real data and arrivals. A 2D E-W velocity model was constructed from the mainland side to the ocean side about 600 km long using the ray-tracing method with layer-striping technique. The preliminary results are: 1) the distribution of Moho depth is basically getting deeper from the west to the east, but becoming shallower rapidly in the area of Coast Range; 2) the crust thickens to the range of 40 km in the mountain area; 3) the Moho depth is shallower than 30 km in the Peikang High and deeper than 32 km at the coast line of Fujan, no crust bulge in the Taiwan Strait; 4) the structures derived from PmP phase and Pn phase from land explosions and onshore-offshore air-gun shots are highly consistent.

True-time-delay photonic beamformer for an L-band phased array radar

NASA Astrophysics Data System (ADS)

Zmuda, Henry; Toughlian, Edward N.; Payson, Paul M.; Malowicki, John E.

1995-10-01

The problem of obtaining a true-time-delay photonic beamformer has recently been a topic of great interest. Many interesting and novel approaches to this problem have been studied. This paper examines the design, construction, and testing of a dynamic optical processor for the control of a 20-element phased array antenna operating at L-band (1.2-1.4 GHz). The approach taken here has several distinct advantages. The actual optical control is accomplished with a class of spatial light modulator known as a segmented mirror device (SMD). This allows for the possibility of controlling an extremely large number (tens of thousands) of antenna elements using integrated circuit technology. The SMD technology is driven by the HDTV and laser printer markets so ultimate cost reduction as well as technological improvements are expected. Optical splitting is efficiently accomplished using a diffractive optical element. This again has the potential for use in antenna array systems with a large number of radiating elements. The actual time delay is achieved using a single acousto-optic device for all the array elements. Acousto-optic device technologies offer sufficient delay as needed for a time steered array. The topological configuration is an optical heterodyne system, hence high, potentially millimeter wave center frequencies are possible by mixing two lasers of slightly differing frequencies. Finally, the entire system is spatially integrated into a 3D glass substrate. The integrated system provides the ruggedness needed in most applications and essentially eliminates the drift problems associated with free space optical systems. Though the system is presently being configured as a beamformer, it has the ability to operate as a general photonic signal processing element in an adaptive (reconfigurable) transversal frequency filter configuration. Such systems are widely applicable in jammer/noise canceling systems, broadband ISDN, and for spread spectrum secure communications. This paper also serves as an update of work-in-progress at the Rome Laboratory Photonics Center Optical Beamforming Lab. The multi-faceted aspects of the design and construction of this state-of-the-art beamforming project will be discussed. Experimental results which demonstrate the performance of the system to-date with regard to both maximum delay and resolution over a broad bandwidth are presented.

Southwest U.S. Seismo-Acoustic Network: An Autonomous Data Aggregation, Detection, Localization and Ground-Truth Bulletin for the Infrasound Community

NASA Astrophysics Data System (ADS)

Jones, K. R.; Arrowsmith, S.

2013-12-01

The Southwest U.S. Seismo-Acoustic Network (SUSSAN) is a collaborative project designed to produce infrasound event detection bulletins for the infrasound community for research purposes. We are aggregating a large, unique, near real-time data set with available ground truth information from seismo-acoustic arrays across New Mexico, Utah, Nevada, California, Texas and Hawaii. The data are processed in near real-time (~ every 20 minutes) with detections being made on individual arrays and locations determined for networks of arrays. The detection and location data are then combined with any available ground truth information and compiled into a bulletin that will be released to the general public directly and eventually through the IRIS infrasound event bulletin. We use the open source Earthworm seismic data aggregation software to acquire waveform data either directly from the station operator or via the Incorporated Research Institutions for Seismology Data Management Center (IRIS DMC), if available. The data are processed using InfraMonitor, a powerful infrasound event detection and localization software program developed by Stephen Arrowsmith at Los Alamos National Laboratory (LANL). Our goal with this program is to provide the infrasound community with an event database that can be used collaboratively to study various natural and man-made sources. We encourage participation in this program directly or by making infrasound array data available through the IRIS DMC or other means. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. R&A 5317326

Efficient receiver tuning using differential evolution strategies

NASA Astrophysics Data System (ADS)

Wheeler, Caleb H.; Toland, Trevor G.

2016-08-01

Differential evolution (DE) is a powerful and computationally inexpensive optimization strategy that can be used to search an entire parameter space or to converge quickly on a solution. The Kilopixel Array Pathfinder Project (KAPPa) is a heterodyne receiver system delivering 5 GHz of instantaneous bandwidth in the tuning range of 645-695 GHz. The fully automated KAPPa receiver test system finds optimal receiver tuning using performance feedback and DE. We present an adaptation of DE for use in rapid receiver characterization. The KAPPa DE algorithm is written in Python 2.7 and is fully integrated with the KAPPa instrument control, data processing, and visualization code. KAPPa develops the technologies needed to realize heterodyne focal plane arrays containing 1000 pixels. Finding optimal receiver tuning by investigating large parameter spaces is one of many challenges facing the characterization phase of KAPPa. This is a difficult task via by-hand techniques. Characterizing or tuning in an automated fashion without need for human intervention is desirable for future large scale arrays. While many optimization strategies exist, DE is ideal for time and performance constraints because it can be set to converge to a solution rapidly with minimal computational overhead. We discuss how DE is utilized in the KAPPa system and discuss its performance and look toward the future of 1000 pixel array receivers and consider how the KAPPa DE system might be applied.

Dust Accumulation and Solar Panel Array Performance on the Mars Exploration Rover (MER) Project

NASA Technical Reports Server (NTRS)

Turgay, Eren H.

2004-01-01

One of the most fundamental design considerations for any space vehicle is its power supply system. Many options exist, including batteries, fuel cells, nuclear reactors, radioisotopic thermal generators (RTGs), and solar panel arrays. Solar arrays have many advantages over other types of power generation. They are lightweight and relatively inexpensive, allowing more mass and funding to be allocated for other important devices, such as scientific instruments. For Mars applications, solar power is an excellent option, especially for long missions. One might think that dust storms would be a problem; however, while dust blocks some solar energy, it also scatters it, making it diffuse rather than beamed. Solar cells are still able to capture this diffuse energy and convert it into substantial electrical power. For these reasons, solar power was chosen to be used on the 1997 Mars Pathfinder mission. The success of this mission set a precedent, as NASA engineers have selected solar power as the energy system of choice for all future Mars missions, including the Mars Exploration Rover (MER) Project. Solar sells have their drawbacks, however. They are difficult to manufacture and are relatively fragile. In addition, solar cells are highly sensitive to different parts of the solar spectrum, and finding the correct balance is crucial to the success of space missions. Another drawback is that the power generated is not a constant with respect to time, but rather changes with the relative angle to the sun. On Mars, dust accumulation also becomes a factor. Over time, dust settles out of the atmosphere and onto solar panels. This dust blocks and shifts the frequency of the incoming light, degrading solar cell performance. My goal is to analyze solar panel telemetry data from the two MERs (Spirit and Opportunity) in an effort to accurately model the effect of dust accumulation on solar panels. This is no easy process due to the large number of factors involved. Changing solar flux (the amount of solar energy reaching the planet), solar spectrum, solar angle, rover tilt, and optical depth (the opacity of the atmosphere due to dust) were the most significant. Microsoft Excel and Visual Basic are used for data analysis. The results of this work will be used to improve the dust accumulation and atmosphere effects model that was first created after the Mars Pathfinder mission. This model will be utilized and applied when considering the design of solar panel array systems on future Mars projects. Based on this data, and depending upon the tenure and application of the mission, designers may also elect to employ special tools to abate dust accumulation, or decide that the expected level of accumulation is acceptable.

Characteristics of arc currents on a negatively biased solar cell array in a plasma

NASA Technical Reports Server (NTRS)

Snyder, D. B.

1984-01-01

The time dependence of the emitted currents during arcing on solar cell arrays is being studied. The arcs are characterized using three parameters: the voltage change of the array during the arc (i.e., the charge lost), the peak current during the arc, and the time constant describing the arc current. This paper reports the dependence of these characteristics on two array parameters, the interconnect bias voltage and the array capacitance to ground. It was found that the voltage change of the array during an arc is nearly equal to the bias voltage. The array capacitance, on the other hand, influences both the peak current and the decay time constant of the arc. Both of these characteristics increase with increasing capacitance.

Sub-barrier fusion cross section measurements with STELLA

NASA Astrophysics Data System (ADS)

Heine, M.; Courtin, S.; Fruet, G.; Jenkins, D. G.; Montanari, D.; Adsley, P.; Beck, C.; Della Negra, S.; Dené, P.; Haas, F.; Hammache, F.; Heitz, G.; Kirsebom, O. S.; Krauth, M.; Lesrel, J.; Meyer, A.; Morris, L.; Regan, P. H.; Richer, M.; Rudigier, M.; de Séréville, N.; Stodel, C.

2018-01-01

The experimental setup STELLA (STELlar LAboratory) is designed for the measurement of deep sub-barrier light heavy ion fusion cross sections. For background suppression the γ-particle coincidence technique is used. In this project, LaBr3 detectors from the UK FATIMA (FAst TIMing Array) collaboration are combined with annular silicon strip detectors customized at IPHC-CNRS, Strasbourg, and the setup is located at Andromède, IPN, Orsay. The commissioning of the experimental approach as well as a sub-barrier 12C +12C → 24Mg∗ cross section measurement campaign are carried out.

Accelerated/abbreviated test methods of the low-cost silicon solar array project. Study 4, task 3: Encapsulation

NASA Technical Reports Server (NTRS)

Kolyer, J. M.; Mann, N. R.

1977-01-01

Methods of accelerated and abbreviated testing were developed and applied to solar cell encapsulants. These encapsulants must provide protection for as long as 20 years outdoors at different locations within the United States. Consequently, encapsulants were exposed for increasing periods of time to the inherent climatic variables of temperature, humidity, and solar flux. Property changes in the encapsulants were observed. The goal was to predict long term behavior of encapsulants based upon experimental data obtained over relatively short test periods.

i-LOVE: ISS-JEM lidar for observation of vegetation environment

NASA Astrophysics Data System (ADS)

Asai, Kazuhiro; Sawada, Haruo; Sugimoto, Nobuo; Mizutani, Kohei; Ishii, Shoken; Nishizawa, Tomoaki; Shimoda, Haruhisa; Honda, Yoshiaki; Kajiwara, Koji; Takao, Gen; Hirata, Yasumasa; Saigusa, Nobuko; Hayashi, Masatomo; Oguma, Hiroyuki; Saito, Hideki; Awaya, Yoshio; Endo, Takahiro; Imai, Tadashi; Murooka, Jumpei; Kobatashi, Takashi; Suzuki, Keiko; Sato, Ryota

2012-11-01

It is very important to watch the spatial distribution of vegetation biomass and changes in biomass over time, representing invaluable information to improve present assessments and future projections of the terrestrial carbon cycle. A space lidar is well known as a powerful remote sensing technology for measuring the canopy height accurately. This paper describes the ISS(International Space Station)-JEM(Japanese Experimental Module)-EF(Exposed Facility) borne vegetation lidar using a two dimensional array detector in order to reduce the root mean square error (RMSE) of tree height due to sloped surface.

Analysis and experimental demonstration of conformal adaptive phase-locked fiber array for laser communications and beam projection applications

NASA Astrophysics Data System (ADS)

Liu, Ling

The primary goal of this research is the analysis, development, and experimental demonstration of an adaptive phase-locked fiber array system for free-space optical communications and laser beam projection applications. To our knowledge, the developed adaptive phase-locked system composed of three fiber collimators (subapertures) with tip-tilt wavefront phase control at each subaperture represents the first reported fiber array system that implements both phase-locking control and adaptive wavefront tip-tilt control capabilities. This research has also resulted in the following innovations: (a) The first experimental demonstration of a phase-locked fiber array with tip-tilt wave-front aberration compensation at each fiber collimator; (b) Development and demonstration of the fastest currently reported stochastic parallel gradient descent (SPGD) system capable of operation at 180,000 iterations per second; (c) The first experimental demonstration of a laser communication link based on a phase-locked fiber array; (d) The first successful experimental demonstration of turbulence and jitter-induced phase distortion compensation in a phase-locked fiber array optical system; (e) The first demonstration of laser beam projection onto an extended target with a randomly rough surface using a conformal adaptive fiber array system. Fiber array optical systems, the subject of this study, can overcome some of the draw-backs of conventional monolithic large-aperture transmitter/receiver optical systems that are usually heavy, bulky, and expensive. The primary experimental challenges in the development of the adaptive phased-locked fiber-array included precise (<5 microrad) alignment of the fiber collimators and development of fast (100kHz-class) phase-locking and wavefront tip-tilt control systems. The precise alignment of the fiber collimator array is achieved through a specially developed initial coarse alignment tool based on high precision piezoelectric picomotors and a dynamic fine alignment mechanism implemented with specially designed and manufactured piezoelectric fiber positioners. Phase-locking of the fiber collimators is performed by controlling the phases of the output beams (beamlets) using integrated polarization-maintaining (PM) fiber-coupled LiNbO3 phase shifters. The developed phase-locking controllers are based on either the SPGD algorithm or the multi-dithering technique. Subaperture wavefront phase tip-tilt control is realized using piezoelectric fiber positioners that are controlled using a computer-based SPGD controller. Both coherent (phase-locked) and incoherent beam combining in the fiber array system are analyzed theoretically and experimentally. Two special fiber-based beam-combining testbeds have been built to demonstrate the technical feasibility of phase-locking compensation prior to free-space operation. In addition, the reciprocity of counter-propagating beams in a phase-locked fiber array system has been investigated. Coherent beam combining in a phase-locking system with wavefront phase tip-tilt compensation at each subaperture is successfully demonstrated when laboratory-simulated turbulence and wavefront jitters are present in the propagation path of the beamlets. In addition, coherent beam combining with a non-cooperative extended target in the control loop is successfully demonstrated.

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

Burke, J. T.; Alan, B. S.; Akindele, O. A.

The goal of this project was to develop a new approach to measuring (n,2n) reactions for isotopes of interest. We set out to measure the 239Pu(n,2n) and 241Pu(n,2n) cross sections by directly detecting the 2n neutrons that are emitted. With the goal of improving the 239Pu(n,2n) cross section and to measure the 241Pu(n,2n) cross section for the first time. To that end, we have constructed a new neutron-charged-particle detector array called NeutronSTARS. It has been described extensively in Casperson et al. [1] and in Akindele et al. [2]. We have used this new neutron-charged-particle array to measure the 241Pu andmore » 239Pu fission neutron multiplicity as a function of equivalent incident-neutron energy from 100 keV to 20 MeV. We have made a preliminary determination of the 239Pu(n,2n) and 241Pu(n,2n) cross sections from the surrogate 240Pu(α,α’2n) and 242Pu(α,α’2n) reactions respectively. The experimental approach, detector array, data analysis, and results to date are summarized in the following sections.« less

Spatiotemporal signal space separation method for rejecting nearby interference in MEG measurements

NASA Astrophysics Data System (ADS)

Taulu, S.; Simola, J.

2006-04-01

Limitations of traditional magnetoencephalography (MEG) exclude some important patient groups from MEG examinations, such as epilepsy patients with a vagus nerve stimulator, patients with magnetic particles on the head or having magnetic dental materials that cause severe movement-related artefact signals. Conventional interference rejection methods are not able to remove the artefacts originating this close to the MEG sensor array. For example, the reference array method is unable to suppress interference generated by sources closer to the sensors than the reference array, about 20-40 cm. The spatiotemporal signal space separation method proposed in this paper recognizes and removes both external interference and the artefacts produced by these nearby sources, even on the scalp. First, the basic separation into brain-related and external interference signals is accomplished with signal space separation based on sensor geometry and Maxwell's equations only. After this, the artefacts from nearby sources are extracted by a simple statistical analysis in the time domain, and projected out. Practical examples with artificial current dipoles and interference sources as well as data from real patients demonstrate that the method removes the artefacts without altering the field patterns of the brain signals.

Report on Operations of the Air Force Geophysics Laboratory Infrared Array Spectrometer

DTIC Science & Technology

1993-01-25

AIR FORCE GEOPHYSICS LABORATORY INFRARED ARRAY... LABORATORY Directorate of Geophysics AIR FORCE MATERIEL COMMAND HANSCOM AIR FORCE BASE, MA 01731-3010 93-27655IEEE|EIIE1ENI This technical report has...ACKNOWLEDGMENT We are grateful to the Air Force Office of Scientific Research , especially Henry Radowski. for their financial corn- mitment to this project.

Dynamic Adaptive Neural Network Arrays: A Neuromorphic Architecture

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

Disney, Adam; Reynolds, John

2015-01-01

Dynamic Adaptive Neural Network Array (DANNA) is a neuromorphic hardware implementation. It differs from most other neuromorphic projects in that it allows for programmability of structure, and it is trained or designed using evolutionary optimization. This paper describes the DANNA structure, how DANNA is trained using evolutionary optimization, and an application of DANNA to a very simple classification task.

Measurements of Ozone, Lightning, and Electric Fields within Thunderstorms over Langmuir Laboratory, New Mexico

NASA Astrophysics Data System (ADS)

Eack, K. B.; Winn, W. P.; Rust, W. D.; Minschwaner, K.; Fredrickson, S.; Kennedy, D.; Edens, H. E.; Kalnajs, L. E.; Rabin, R. M.; Lu, G. P.; Bonin, D.

2008-12-01

A field project was conducted at the Langmuir Laboratory for Atmospheric Research during the summer of 2008 in an effort to better understand the direct production of ozone within electrically active storms. Five balloon flights were successfully launched into thunderstorms during this project. In situ measurements from the balloon instrument package included ozone mixing ratio, electric field strength, meteorological variables, and GPS location and timing. Lightning discharges were identified within each storm using a ground based lightning mapping array. The data show that the instruments ascended through regions of high electric fields within the sampled storms, and in some cases the balloon was in very close proximity to lightning. Relationships between electric field, lightning, and ozone observed during these flights will be discussed.

Instrumentation for single-dish observations with The Greenland Telescope

NASA Astrophysics Data System (ADS)

Grimes, Paul K.; Asada, K.; Blundell, R.; Burgos, R.; Chang, H.-H.; Chen, M. T.; Goldie, D.; Groppi, C.; Han, C. C.; Ho, P. T. P.; Huang, Y. D.; Inoue, M.; Kubo, D.; Koch, P.; Leech, J.; de Lera Acedo, E.; Martin-Cocher, P.; Nishioka, H.; Nakamura, M.; Matsushita, S.; Paine, S. N.; Patel, N.; Raffin, P.; Snow, W.; Sridharan, T. K.; Srinivasan, R.; Thomas, C. N.; Tong, E.; Wang, M.-J.; Wheeler, C.; Withington, S.; Yassin, G.; Zeng, L.-Z.

2014-07-01

The Greenland Telescope project will deploy and operate a 12m sub-millimeter telescope at the highest point of the Greenland i e sheet. The Greenland Telescope project is a joint venture between the Smithsonian As- trophysical Observatory (SAO) and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA). In this paper we discuss the concepts, specifications, and science goals of the instruments being developed for single-dish observations with the Greenland Telescope, and the coupling optics required to couple both them and the mm-VLBI receivers to antenna. The project will outfit the ALMA North America prototype antenna for Arctic operations and deploy it to Summit Station,1 a NSF operated Arctic station at 3,100m above MSL on the Greenland I e Sheet. This site is exceptionally dry, and promises to be an excellent site for sub-millimeter astronomical observations. The main science goal of the Greenland Telescope is to carry out millimeter VLBI observations alongside other telescopes in Europe and the Americas, with the aim of resolving the event horizon of the super-massive black hole at the enter of M87. The Greenland Telescope will also be outfitted for single-dish observations from the millimeter-wave to Tera-hertz bands. In this paper we will discuss the proposed instruments that are currently in development for the Greenland Telescope - 350 GHz and 650 GHz heterodyne array receivers; 1.4 THz HEB array receivers and a W-band bolometric spectrometer. SAO is leading the development of two heterodyne array instruments for the Greenland Telescope, a 48- pixel, 325-375 GHz SIS array receiver, and a 4 pixel, 1.4 THz HEB array receiver. A key science goal for these instruments is the mapping of ortho and para H2D+ in old protostellar ores, as well as general mapping of CO and other transitions in molecular louds. An 8-pixel prototype module for the 350 GHz array is currently being built for laboratory and operational testing on the Greenland Telescope. Arizona State University are developing a 650 GHz 256 pixel SIS array receiver based on the KAPPa SIS mixer array technology and ASIAA are developing 1.4 THz HEB single pixel and array receivers. The University of Cambridge and SAO are collaborating on the development of the CAMbridge Emission Line Surveyor (CAMELS), a W-band `on- hip' spectrometer instrument with a spectral resolution of R ~ 3000. CAMELS will consist of two pairs of horn antennas, feeding super conducting niobium nitride filter banks read by tantalum based Kinetic Inductance Detectors.

Expanded Very Large Array Nova Project Observations of the Classical Nova V1723 Aquilae

NASA Astrophysics Data System (ADS)

Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.; O'Brien, T. J.

2011-09-01

We present radio light curves and spectra of the classical nova V1723 Aql obtained with the Expanded Very Large Array (EVLA). This is the first paper to showcase results from the EVLA Nova Project, which comprises a team of observers and theorists utilizing the greatly enhanced sensitivity and frequency coverage of EVLA radio observations, along with observations at other wavelengths, to reach a deeper understanding of the energetics, morphology, and temporal characteristics of nova explosions. Our observations of V1723 Aql span 1-37 GHz in frequency, and we report on data from 14 to 175 days following the time of the nova explosion. The broad frequency coverage and frequent monitoring show that the radio behavior of V1723 Aql does not follow the classic Hubble-flow model of homologous spherically expanding thermal ejecta. The spectra are always at least partially optically thin, and the flux rises on faster timescales than can be reproduced with linear expansion. Therefore, any description of the underlying physical processes must go beyond this simple picture. The unusual spectral properties and light curve evolution might be explained by multiple emitting regions or shocked material. Indeed, X-ray observations from Swift reveal that shocks are likely present.

Expanded Very Large Array Nova Project Observations of the Classical NovaV1723 Aquilae

NASA Technical Reports Server (NTRS)

Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.;

Design of a Novel Flexible Capacitive Sensing Mattress for Monitoring Sleeping Respiratory

PubMed Central

Chang, Wen-Ying; Huang, Chien-Chun; Chen, Chi-Chun; Chang, Chih-Cheng; Yang, Chin-Lung

2014-01-01

In this paper, an algorithm to extract respiration signals using a flexible projected capacitive sensing mattress (FPCSM) designed for personal health assessment is proposed. Unlike the interfaces of conventional measurement systems for poly-somnography (PSG) and other alternative contemporary systems, the proposed FPCSM uses projected capacitive sensing capability that is not worn or attached to the body. The FPCSM is composed of a multi-electrode sensor array that can not only observe gestures and motion behaviors, but also enables the FPCSM to function as a respiration monitor during sleep using the proposed approach. To improve long-term monitoring when body movement is possible, the FPCSM enables the selection of data from the sensing array, and the FPCSM methodology selects the electrodes with the optimal signals after the application of a channel reduction algorithm that counts the reversals in the capacitive sensing signals as a quality indicator. The simple algorithm is implemented in the time domain. The FPCSM system is used in experimental tests and is simultaneously compared with a commercial PSG system for verification. Multiple synchronous measurements are performed from different locations of body contact, and parallel data sets are collected. The experimental comparison yields a correlation coefficient of 0.88 between FPCSM and PSG, demonstrating the feasibility of the system design. PMID:25420152

Generation of Olympic logo with freeform lens array

NASA Astrophysics Data System (ADS)

Liu, Chengkun; Huang, Qilu; Qiu, Yishen; Chen, Weijuan; Liao, Tingdi

2017-10-01

In this paper, the Olympic rings pattern is generated by using freeform lens array and illumination light source array. Based on nonimaging optics, the freeform lens array is designed for point light source, which can generate the focused pattern of annular light spot. In order to obtain the Olympic logo pattern of five rings, the array with five freeform lenses is used. By adjusting the emission angle of each light source, the annular spot is obtained at different positions of the target plane and the Olympic rings logo is formed. We used the shading plate on the surface of the freeform lens to reduce the local light intensity so that the light spot overall irradiance distribution is more uniform. We designed a freeform lens with aperture of 26.2mm, focal length of 2000mm and the diameter of a single annual spot is 400mm. We modeled freeform lens and simulated by optical software TracePro. The ray tracing results show that the Olympic rings with uniform illumination can be obtained on the target plane with the optical efficiency up to 85.7%. At the same time, this paper also studies the effects of the target plane defocusing on the spot pattern. Simulations show that when the distance of the receiving surface to the focal plane varies within 300mm, a reasonable uniform and small distorted light spot pattern can be obtained. Compared with the traditional projection method, our method of design has the advantages of high optical efficiency, low cost and the pattern is clear and uniform.

High frame-rate computational ghost imaging system using an optical fiber phased array and a low-pixel APD array.

PubMed

Liu, Chunbo; Chen, Jingqiu; Liu, Jiaxin; Han, Xiang'e

2018-04-16

To obtain a high imaging frame rate, a computational ghost imaging system scheme is proposed based on optical fiber phased array (OFPA). Through high-speed electro-optic modulators, the randomly modulated OFPA can provide much faster speckle projection, which can be precomputed according to the geometry of the fiber array and the known phases for modulation. Receiving the signal light with a low-pixel APD array can effectively decrease the requirement on sampling quantity and computation complexity owing to the reduced data dimensionality while avoiding the image aliasing due to the spatial periodicity of the speckles. The results of analysis and simulation show that the frame rate of the proposed imaging system can be significantly improved compared with traditional systems.

Optimizing Satellite Communications With Adaptive and Phased Array Antennas

NASA Technical Reports Server (NTRS)

Ingram, Mary Ann; Romanofsky, Robert; Lee, Richard Q.; Miranda, Felix; Popovic, Zoya; Langley, John; Barott, William C.; Ahmed, M. Usman; Mandl, Dan

2004-01-01

A new adaptive antenna array architecture for low-earth-orbiting satellite ground stations is being investigated. These ground stations are intended to have no moving parts and could potentially be operated in populated areas, where terrestrial interference is likely. The architecture includes multiple, moderately directive phased arrays. The phased arrays, each steered in the approximate direction of the satellite, are adaptively combined to enhance the Signal-to-Noise and Interference-Ratio (SNIR) of the desired satellite. The size of each phased array is to be traded-off with the number of phased arrays, to optimize cost, while meeting a bit-error-rate threshold. Also, two phased array architectures are being prototyped: a spacefed lens array and a reflect-array. If two co-channel satellites are in the field of view of the phased arrays, then multi-user detection techniques may enable simultaneous demodulation of the satellite signals, also known as Space Division Multiple Access (SDMA). We report on Phase I of the project, in which fixed directional elements are adaptively combined in a prototype to demodulate the S-band downlink of the EO-1 satellite, which is part of the New Millennium Program at NASA.

The Cherenkov Telescope Array For Very High-Energy Astrophysics

NASA Astrophysics Data System (ADS)

Kaaret, Philip

2015-08-01

The field of very high energy (VHE) astrophysics had been revolutionized by the results from ground-based gamma-ray telescopes, including the current imaging atmospheric Cherenkov telescope (IACT) arrays: HESS, MAGIC and VERITAS. A worldwide consortium of scientists from 29 countries has formed to propose the Cherenkov Telescope Array (CTA) that will capitalize on the power of this technique to greatly expand the scientific reach of ground-based gamma-ray telescopes. CTA science will include key topics such as the origin of cosmic rays and cosmic particle acceleration, understanding extreme environments in regions close to neutron stars and black holes, and exploring physics frontiers through, e.g., the search for WIMP dark matter, axion-like particles and Lorentz invariance violation. CTA is envisioned to consist of two large arrays of Cherenkov telescopes, one in the southern hemisphere and one in the north. Each array will contain telescopes of different sizes to provide a balance between cost and array performance over an energy range from below 100 GeV to above 100 TeV. Compared to the existing IACT arrays, CTA will have substantially better angular resolution and energy resolution, will cover a much wider energy range, and will have up to an order of magnitude better sensitivity. CTA will also be operated as an open observatory and high-level CTA data will be placed into the public domain; these aspects will enable broad participation in CTA science from the worldwide scientific community to fully capitalize on CTA's potential. This talk will: 1) review the scientific motivation and capabilities of CTA, 2) provide an overview of the technical design and the status of prototype development, and 3) summarize the current status of the project in terms of its proposed organization and timeline. The plans for access to CTA data and opportunities to propose for CTA observing time will be highlighed.Presented on behalf of the CTA Consortium.

The 17th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1981-01-01

Progress made by the Low-Cost Solar Array Project during the period September 1980 to February 1981 is described. Included are reports on project analysis and integration; technology development in silicon material, large-area silicon sheet and encapsulation; production process and equipment development; engineering, and operations. A report on and copies of visual presentations made at the Project Integration Meeting held at Pasadena, California on February 4 and 5, 1981 are also included.

Quantification of the effectiveness of handheld equipment for ground verification of detected rail internal defects.

DOT National Transportation Integrated Search

2014-04-01

The objective of this project was to quantify the effectiveness of the rail inspection ground verification process. More specifically, : the project focused on comparing the effectiveness of conventional versus phased array probes to manually detect ...

Encapsulation task of the low-cost silicon solar array project. Investigation of test methods, material properties, and processes for solar cell encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.; Baum, B.; White, R. A.

1978-01-01

The results of an investigation of solar module encapsulation systems applicable to the Low-Cost Solar Array Project 1986 cost and performance goals are presented. Six basic construction elements were identified and their specific uses in module construction defined. A uniform coating basis was established for each element. The survey results were also useful in revealing price ranges for classes of materials and estimating the cost allocation for each element within the encapsulating cost goal. The six construction elements were considered to be substrates, superstrates, pottants, adhesives, outer covers and back covers.

Characterizing opto-electret based paper speakers by using a real-time projection Moiré metrology system

NASA Astrophysics Data System (ADS)

Chang, Ya-Ling; Hsu, Kuan-Yu; Lee, Chih-Kung

2016-03-01

Advancement of distributed piezo-electret sensors and actuators facilitates various smart systems development, which include paper speakers, opto-piezo/electret bio-chips, etc. The array-based loudspeaker system possess several advantages over conventional coil speakers, such as light-weightness, flexibility, low power consumption, directivity, etc. With the understanding that the performance of the large-area piezo-electret loudspeakers or even the microfluidic biochip transport behavior could be tailored by changing their dynamic behaviors, a full-field real-time high-resolution non-contact metrology system was developed. In this paper, influence of the resonance modes and the transient vibrations of an arraybased loudspeaker system on the acoustic effect were measured by using a real-time projection moiré metrology system and microphones. To make the paper speaker even more versatile, we combine the photosensitive material TiOPc into the original electret loudspeaker. The vibration of this newly developed opto-electret loudspeaker could be manipulated by illuminating different light-intensity patterns. Trying to facilitate the tailoring process of the opto-electret loudspeaker, projection moiré was adopted to measure its vibration. By recording the projected fringes which are modulated by the contours of the testing sample, the phase unwrapping algorithm can give us a continuous phase distribution which is proportional to the object height variations. With the aid of the projection moiré metrology system, the vibrations associated with each distinctive light pattern could be characterized. Therefore, we expect that the overall acoustic performance could be improved by finding the suitable illuminating patterns. In this manuscript, the system performance of the projection moiré and the optoelectret paper speakers were cross-examined and verified by the experimental results obtained.

High resolution, wide field of view, real time 340GHz 3D imaging radar for security screening

NASA Astrophysics Data System (ADS)

Robertson, Duncan A.; Macfarlane, David G.; Hunter, Robert I.; Cassidy, Scott L.; Llombart, Nuria; Gandini, Erio; Bryllert, Tomas; Ferndahl, Mattias; Lindström, Hannu; Tenhunen, Jussi; Vasama, Hannu; Huopana, Jouni; Selkälä, Timo; Vuotikka, Antti-Jussi

2017-05-01

The EU FP7 project CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) is developing a demonstrator system for next generation airport security screening which will combine passive and active submillimeter wave imaging sensors. We report on the development of the 340 GHz 3D imaging radar which achieves high volumetric resolution over a wide field of view with high dynamic range and a high frame rate. A sparse array of 16 radar transceivers is coupled with high speed mechanical beam scanning to achieve a field of view of 1 x 1 x 1 m3 and a 10 Hz frame rate.

Orthogonally referenced integrated ensemble for navigation and timing

DOEpatents

Smith, Stephen Fulton; Moore, James Anthony

2013-02-26

An orthogonally referenced integrated ensemble for navigation and timing includes a dual-polyhedral oscillator array, including an outer sensing array of oscillators and an inner clock array of oscillators situated inside the outer sensing array. The outer sensing array includes a first pair of sensing oscillators situated along a first axis of the outer sensing array, a second pair of sensing oscillators situated along a second axis of the outer sensing array, and a third pair of sensing oscillators situated along a third axis of the outer sensing array. The inner clock array of oscillators includes a first pair of clock oscillators situated along a first axis of the inner clock array, a second pair of clock oscillators situated along a second axis of the inner clock array, and a third pair of clock oscillators situated along a third axis of the inner clock array.

Orthogonally referenced integrated ensemble for navigation and timing

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

Smith, Stephen Fulton; Moore, James Anthony

2014-04-01

An orthogonally referenced integrated ensemble for navigation and timing includes a dual-polyhedral oscillator array, including an outer sensing array of oscillators and an inner clock array of oscillators situated inside the outer sensing array. The outer sensing array includes a first pair of sensing oscillators situated along a first axis of the outer sensing array, a second pair of sensing oscillators situated along a second axis of the outer sensing array, and a third pair of sensing oscillators situated along a third axis of the outer sensing array. The inner clock array of oscillators includes a first pair of clockmore » oscillators situated along a first axis of the inner clock array, a second pair of clock oscillators situated along a second axis of the inner clock array, and a third pair of clock oscillators situated along a third axis of the inner clock array.« less

Automated Array Assembly, Phase 2

NASA Technical Reports Server (NTRS)

Carbajal, B. G.

1979-01-01

The Automated Array Assembly Task, Phase 2 of the Low Cost Silicon Solar Array Project is a process development task. The contract provides for the fabrication of modules from large area tandem junction cells (TJC). During this quarter, effort was focused on the design of a large area, approximately 36 sq cm, TJC and process verification runs. The large area TJC design was optimized for minimum I squared R power losses. In the TJM activity, the cell-module interfaces were defined, module substrates were formed and heat treated and clad metal interconnect strips were fabricated.

Some design considerations for a synthetic aperture optical telescope array

NASA Astrophysics Data System (ADS)

Scott, P. W.

1984-01-01

Several design considerations inherent in the configuration of phased array transmission of multiwavelength laser beams are discussed. Attention is focused on the U.S.A.F. phased array (PHASAR) demonstration project, where problems have been encountered in dividing the beam(s), controlling the optical path differences between subapertures, and expanding individual beams.A piston-driven path length adjustment mechanism has been selected, along with an active control system and proven components for stability maintenance. The necessity of developing broadband, high reflectivity low phase shift coatings for the system mirrors is stressed.

Alicudi project

NASA Astrophysics Data System (ADS)

Arcidiacono, V.; Corsi, S.; Iliceto, A.; Previ, A.; Taschini, A.

Design features and goals of the photovoltaic array power system for Alicudi Island hamlets are described. The array will have two 40 kWe sections, a 3 kAh battery system, an inverter to assure three-phase, ac current, a data acquisition system, and a 60 kVA diesel back-up system. The semi-arid conic volcanic island has terraces and a slope ideally suited to installation of the array. A computer simulation was developed to optimize the output and load profile matching using historical insolation data. A block diagram is provided of the electricity distribution network.

VizieR Online Data Catalog: 8 Fermi GRB afterglows follow-up (Singer+, 2015)

NASA Astrophysics Data System (ADS)

Singer, L. P.; Kasliwal, M. M.; Cenko, S. B.; Perley, D. A.; Anderson, G. E.; Anupama, G. C.; Arcavi, I.; Bhalerao, V.; Bue, B. D.; Cao, Y.; Connaughton, V.; Corsi, A.; Cucchiara, A.; Fender, R. P.; Fox, D. B.; Gehrels, N.; Goldstein, A.; Gorosabel, J.; Horesh, A.; Hurley, K.; Johansson, J.; Kann, D. A.; Kouveliotou, C.; Huang, K.; Kulkarni, S. R.; Masci, F.; Nugent, P.; Rau, A.; Rebbapragada, U. D.; Staley, T. D.; Svinkin, D.; Thone, C. C.; de Ugarte Postigo, A.; Urata, Y.; Weinstein, A.

2015-10-01

In this work, we present the GBM-iPTF (intermediate Palomar Transient Factory) afterglows from the first 13 months of this project. Follow-up observations include R-band photometry from the P48, multicolor photometry from the P60, spectroscopy (acquired with the P200, Keck, Gemini, APO, Magellan, Very Large Telescope (VLT), and GTC), and radio observations with the Very Large Array (VLA), the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the Australia Telescope Compact Array (ATCA), and the Arcminute Microkelvin Imager (AMI). (3 data files).

Powering the future - a new generation of high-performance solar arrays

NASA Astrophysics Data System (ADS)

Geyer, Freddy; Caswell, Doug; Signorini, Carla

2007-08-01

Funded by ESA's Advanced Research in Telecommunication (ARTES) programme, Thales Alenia Space has developed a new generation of high-power ultra-lightweight solar arrays for telecommunications satellites. Thanks to close cooperation with its industrial partners in Europe, the company has generically qualified a solar array io meet market needs. Indeed, three flight projects were already using the new design as qualification was completed. In addition, the excellent mechanical and thermal behaviour of the new panel structure are contributing to other missions such as Pleïades and LISA Pathfinder.

Microseismic monitoring of CO2 injection at the Penn West Enhanced Oil Recovery pilot project, Canada: implications for detection of wellbore leakage.

PubMed

Martínez-Garzón, Patricia; Bohnhoff, Marco; Kwiatek, Grzegorz; Zambrano-Narváez, Gonzalo; Chalaturnyk, Rick

2013-09-02

A passive seismic monitoring campaign was carried out in the frame of a CO2-Enhanced Oil Recovery (EOR) pilot project in Alberta, Canada. Our analysis focuses on a two-week period during which prominent downhole pressure fluctuations in the reservoir were accompanied by a leakage of CO2 and CH4 along the monitoring well equipped with an array of short-period borehole geophones. We applied state of the art seismological processing schemes to the continuous seismic waveform recordings. During the analyzed time period we did not find evidence of induced micro-seismicity associated with CO2 injection. Instead, we identified signals related to the leakage of CO2 and CH4, in that seven out of the eight geophones show a clearly elevated noise level framing the onset time of leakage along the monitoring well. Our results confirm that micro-seismic monitoring of reservoir treatment can contribute towards improved reservoir monitoring and leakage detection.

Microseismic Monitoring of CO2 Injection at the Penn West Enhanced Oil Recovery Pilot Project, Canada: Implications for Detection of Wellbore Leakage

PubMed Central

Martínez-Garzón, Patricia; Bohnhoff, Marco; Kwiatek, Grzegorz; Zambrano-Narváez, Gonzalo; Chalaturnyk, Rick

2013-01-01

A passive seismic monitoring campaign was carried out in the frame of a CO2-Enhanced Oil Recovery (EOR) pilot project in Alberta, Canada. Our analysis focuses on a two-week period during which prominent downhole pressure fluctuations in the reservoir were accompanied by a leakage of CO2 and CH4 along the monitoring well equipped with an array of short-period borehole geophones. We applied state of the art seismological processing schemes to the continuous seismic waveform recordings. During the analyzed time period we did not find evidence of induced micro-seismicity associated with CO2 injection. Instead, we identified signals related to the leakage of CO2 and CH4, in that seven out of the eight geophones show a clearly elevated noise level framing the onset time of leakage along the monitoring well. Our results confirm that micro-seismic monitoring of reservoir treatment can contribute towards improved reservoir monitoring and leakage detection. PMID:24002229

A Brief Description of My Projects

NASA Technical Reports Server (NTRS)

Barnes, Tobin

2016-01-01

My internship was in the IDC which consist of a machine shop and an array of design space. During my tour I worked on a wide variety of projects some of which included design, research, machining and fabrication. I gained further knowledge on some machines that I have had prior experience on such as the lathe and Hurco CNC machines. The first thing we did was complete our checkout in the machine shop which went pretty well, since I was already familiar with most of the machines. I also did a couple of practice parts on some of the machines, I made a name block on the CNC machine and I also used the vertical milling machine to complete this project. One of the other projects that I did was machine a hammer with my initials with the use of the lathe and CNC machine, this project took much longer since I had to set up a cylindrical piece on the CNC machine. The first project that I began work on was the Systems Engineering & Management Advancement Program (SEPMAP) Hexacopter project and helped them to assemble and modify one of their particle capture doors on their boxes. After a while we ended up helping them make a hinge and holes to reduce the weight of their design. We helped the NASA Extreme Environment Mission Operations (NEEMO) team a bit with some of their name tags and assembly of some of their underwater parts. One of the more challenging projects was a rail that came in with a rather weirdly drawn part. The biggest project that I worked on was the solar array project. Which consisted of a variety of machining and 3D printing and it took me about 3 different times of re-designing to come up with a final prototype. Along with this project I also had to complete a project in which I had to modify a thermos. This was rather simple since I just had to draw up a part and print it out on the 3D printer. I also learned how to use Pro E/Creo parametric to design a square block and print it on the 3D Printer. All of these projects increased my experience on all of the machines and equipment that I used. I also got to tweak my design skills and better understand how to modify my designs and how to improve those specific designs.

Digital Radiography and Computed Tomography Project -- Fully Integrated Linear Detector ArrayStatus Report

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

Tim Roney; Robert Seifert; Bob Pink

2011-09-01

The field-portable Digital Radiography and Computed Tomography (DRCT) x-ray inspection systems developed for the Project Manager for NonStockpile Chemical Materiel (PMNSCM) over the past 13 years have used linear diode detector arrays from two manufacturers; Thomson and Thales. These two manufacturers no longer produce this type of detector. In the interest of insuring the long term viability of the portable DRCT single munitions inspection systems and to improve the imaging capabilities, this project has been investigating improved, commercially available detectors. During FY-10, detectors were evaluated and one in particular, manufactured by Detection Technologies (DT), Inc, was acquired for possible integrationmore » into the DRCT systems. The remainder of this report describes the work performed in FY-11 to complete evaluations and fully integrate the detector onto a representative DRCT platform.« less

Flat-plate solar array project. Volume 3: Silicon sheet: Wafers and ribbons

NASA Technical Reports Server (NTRS)

Briglio, A.; Dumas, K.; Leipold, M.; Morrison, A.

1986-01-01

The primary objective of the Silicon Sheet Task of the Flat-Plate Solar Array (FSA) Project was the development of one or more low cost technologies for producing silicon sheet suitable for processing into cost-competitive solar cells. Silicon sheet refers to high purity crystalline silicon of size and thickness for fabrication into solar cells. Areas covered in the project were ingot growth and casting, wafering, ribbon growth, and other sheet technologies. The task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the task cost goals were not achieved.

Proceedings of the Third Infrared Detector Technology Workshop

NASA Technical Reports Server (NTRS)

Mccreight, Craig R. (Compiler)

1989-01-01

This volume consists of 37 papers which summarize results presented at the Third Infrared Detector Technology Workshop, held February 7-9, 1989, at Ames Research Center. The workshop focused on infrared (IR) detector, detector array, and cryogenic electronic technologies relevant to low-background space astronomy. Papers on discrete IR detectors, cryogenic readouts, extrinsic and intrinsic IR arrays, and recent results from ground-based observations with integrated arrays were given. Recent developments in the second-generation Hubble Space Telescope (HST) infrared spectrometer and in detectors and arrays for the European Space Agency's Infrared Space Observatory (ISO) are also included, as are status reports on the Space Infrared Telescope Facility (SIRTF) and the Stratospheric Observatory for Infrared Astronomy (SOFIA) projects.

Condenser for photolithography system

DOEpatents

Sweatt, William C.

2004-03-02

A condenser for a photolithography system, in which a mask image from a mask is projected onto a wafer through a camera having an entrance pupil, includes a source of propagating radiation, a first mirror illuminated by the radiation, a mirror array illuminated by the radiation reflected from said first mirror, and a second mirror illuminated by the radiation reflected from the array. The mirror array includes a plurality of micromirrors. Each of the micromirrors is selectively actuatable independently of each other. The first mirror and the second mirror are disposed such that the source is imaged onto a plane of the mask and the mirror array is imaged into the entrance pupil of the camera.

Advanced Rainbow Solar Photovoltaic Arrays

NASA Technical Reports Server (NTRS)

Mardesich, Nick; Shields, Virgil

2003-01-01

Photovoltaic arrays of the rainbow type, equipped with light-concentrator and spectral-beam-splitter optics, have been investigated in a continuing effort to develop lightweight, high-efficiency solar electric power sources. This investigation has contributed to a revival of the concept of the rainbow photovoltaic array, which originated in the 1950s but proved unrealistic at that time because the selection of solar photovoltaic cells was too limited. Advances in the art of photovoltaic cells since that time have rendered the concept more realistic, thereby prompting the present development effort. A rainbow photovoltaic array comprises side-by-side strings of series-connected photovoltaic cells. The cells in each string have the same bandgap, which differs from the bandgaps of the other strings. Hence, each string operates most efficiently in a unique wavelength band determined by its bandgap. To obtain maximum energy-conversion efficiency and to minimize the size and weight of the array for a given sunlight input aperture, the sunlight incident on the aperture is concentrated, then spectrally dispersed onto the photovoltaic array plane, whereon each string of cells is positioned to intercept the light in its wavelength band of most efficient operation. The number of cells in each string is chosen so that the output potentials of all the strings are the same; this makes it possible to connect the strings together in parallel to maximize the output current of the array. According to the original rainbow photovoltaic concept, the concentrated sunlight was to be split into multiple beams by use of an array of dichroic filters designed so that each beam would contain light in one of the desired wavelength bands. The concept has since been modified to provide for dispersion of the spectrum by use of adjacent prisms. A proposal for an advanced version calls for a unitary concentrator/ spectral-beam-splitter optic in the form of a parabolic curved Fresnel-like prism array with panels of photovoltaic cells on two sides (see figure). The surface supporting the solar cells can be adjusted in length or angle to accommodate the incident spectral pattern. An unoptimized prototype assembly containing ten adjacent prisms and three photovoltaic cells with different bandgaps (InGaP2, GaAs, and InGaAs) was constructed to demonstrate feasibility. The actual array will consist of a lightweight thin-film silicon layer of prisms curved into a parabolic shape. In an initial test under illumination of 1 sun at zero airmass, the energy-conversion efficiency of the assembly was found to be 20 percent. Further analysis of the data from this test led to a projected energy conversion efficiency as high as 41 percent for an array of 6 cells or strings (GaP, AlGaAs, InGaP2, GaAs, and two different InGaAs cells or strings).

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

Burnison, Shaughn; Livers-Douglas, Amanda; Barajas-Olalde, Cesar

The scalable, automated, semipermanent seismic array (SASSA) project led and managed by the Energy & Environmental Research Center (EERC) was designed as a 3-year proof-of-concept study to evaluate and demonstrate an innovative application of the seismic method. The concept was to use a sparse surface array of 96 nodal seismic sensors paired with a single, remotely operated active seismic source at a fixed location to monitor for CO 2 saturation changes in a subsurface reservoir by processing the data for time-lapse changes at individual, strategically chosen reservoir reflection points. The combination of autonomous equipment and modern processing algorithms was usedmore » to apply the seismic method in a manner different from the normal paradigm of collecting a spatially dense data set to produce an image. It was used instead to monitor individual, strategically chosen reservoir reflection points for detectable signal character changes that could be attributed to the passing of a CO 2 saturation front or, possibly, changes in reservoir pressure. Data collection occurred over the course of 1 year at an oil field undergoing CO 2 injection for enhanced oil recovery (EOR) and focused on four overlapping “five-spot” EOR injector–producer patterns. Selection, procurement, configuration, installation, and testing of project equipment and collection of five baseline data sets were completed in advance of CO 2 injection within the study area. Weekly remote data collection produced 41 incremental time-lapse records for each of the 96 nodes. Validation was provided by two methods: 1) a conventional 2-D seismic line acquired through the center of the study area before injection started and again after the project ended and processed in a time-lapse manner and 2) by CO 2 saturation maps created from reservoir simulations based on injection and production history matching. Interpreted results were encouraging but mixed, with indications of changes likely due to the presence of CO 2 on some node reflection points where and when effects would be expected and noneffects where no CO 2 was expected, while results at some locations where simulation outputs suggested CO 2 should be present were ambiguous. Acquisition noise impacted interpretation of data at several locations. Many lessons learned were generated by the study to inform and improve results on a follow-up study. The ultimate aim of the project was to evaluate whether deployment of a SASSA technology can provide a useful and cost-effective monitoring solution for future CO 2 injection projects. The answer appears to be affirmative, with the expectation that lessons learned applied to future iterations, together with technology advances, will likely result in significant improvements.« less

Recent results and performance of the multi-gap resistive plate chambers network for the EEE Project

NASA Astrophysics Data System (ADS)

Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D`Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Licciulli, F.; Maggiora, A.; Maragoto Rodriguez, O.; Maron, G.; Martelli, B.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Park, W.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Visnyei, O. B.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeusky, R.

2016-11-01

The Extreme Energy Events (EEE) Project is devoted to the study of Extensive Atmospheric Showers through a network of muon telescopes, installed in High Schools, with the further aim of introducing young students to particle and astroparticle physics. Each telescope is a tracking detector composed of three Multi-gap Resistive Plate Chambers (MRPC) with an active area of 1.60 × 0.80 m2. Their characteristics are similar to the ones built for the Time Of Flight array of the ALICE Experimentat LHC . The EEE Project started with a few pilot towns, where the telescopes have been taking data since 2008, and it has been constantly extended, reaching at present more than 50 MRPCs telescopes. They are spread across Italy with two additional stations at CERN, covering an area of around 3 × 105 km2, with a total surface area for all the MRPCs of 190 m2. A comprehensive description of the MRPCs network is reported here: efficiency, time and spatial resolution measured using cosmic rays hitting the telescopes. The most recent results on the detector and physics performance from a series of coordinated data acquisition periods are also presented.

High-performance, flexible, deployable array development for space applications

NASA Technical Reports Server (NTRS)

Gehling, Russell N.; Armstrong, Joseph H.; Misra, Mohan S.

1994-01-01

Flexible, deployable arrays are an attractive alternative to conventional solar arrays for near-term and future space power applications, particularly due to their potential for high specific power and low storage volume. Combined with low-cost flexible thin-film photovoltaics, these arrays have the potential to become an enabling or an enhancing technology for many missions. In order to expedite the acceptance of thin-film photovoltaics for space applications, however, parallel development of flexible photovoltaics and the corresponding deployable structure is essential. Many innovative technologies must be incorporated in these arrays to ensure a significant performance increase over conventional technologies. For example, innovative mechanisms which employ shape memory alloys for storage latches, deployment mechanisms, and array positioning gimbals can be incorporated into flexible array design with significant improvement in the areas of cost, weight, and reliability. This paper discusses recent activities at Martin Marietta regarding the development of flexible, deployable solar array technology. Particular emphasis is placed on the novel use of shape memory alloys for lightweight deployment elements to improve the overall specific power of the array. Array performance projections with flexible thin-film copper-indium-diselenide (CIS) are presented, and government-sponsored solar array programs recently initiated at Martin Marietta through NASA and Air Force Phillips Laboratory are discussed.

An Overview of LANL's New Hurricane Lightning Project (Invited)

NASA Astrophysics Data System (ADS)

Jeffery, C. A.; Shao, X.; Reisner, J.; Kao, C. J.; Brockwell, M.; Chylek, P.; Fierro, A.; Galassi, M.; Godinez, H. C.; Guimond, S.; Hamlin, T.; Henderson, B. G.; Ho, C.; Holden, D.; Light, T. E.; O'Connor, N.; Suszcynsky, D. M.

2009-12-01

For the last two years, Los Alamos National Laboratory has sponsored an internal hurricane lightning project with four main goals: (1) To develop and deploy a new dual VLF/VHF lightning mapping array in the Mississippi River Delta south of New Orleans. (2) To develop a new hurricane forecast capability with fully prognostic cloud electrification and lightning discharge physics, based on a model framework developed at Oklahoma University. (3) To develop a new data assimilation approach for ingesting LANL lightning data into our forecast model that exploits the phenomenological relationship between lightning occurrence and intense convection. (4) To demonstrate that the assimilation of lightning data from the new LANL Gulf array into the hurricane forecast model improves the prediction of rapid intensification (RI), when RI is driven by eyewall adjustment (axisymmetrization) triggered by intense convective events (hot towers). In this talk, I present an overview of LANL's new hurricane lighting project, and the progress we have made to-date in achieving the project's four main goals.

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

Casperson, R. J.; Burke, J. T.; Hughes, R. O.

Directly measuring (n,2n) cross sections on short-lived actinides presents a number of experimental challenges. The surrogate reaction technique is an experimental method for measuring cross sections on short-­lived isotopes, and it provides a unique solution for measuring (n,2n) cross sections. This technique involves measuring a charged-­particle reaction cross section, where the reaction populates the same compound nucleus as the reaction of interest. To perform these surrogate (n,2n) cross section measurements, a silicon telescope array has been placed along a beam line at the Texas A&M University Cyclotron Institute, which is surrounded by a large tank of gadolinium-doped liquid scintillator, whichmore » acts as a neutron detector. The combination of the charge-particle and neutron-detector arrays is referred to as NeutronSTARS. In the analysis procedure for calculating the (n,2n) cross section, the neutron detection efficiency and time structure plays an important role. Due to the lack of availability of isotropic, mono-energetic neutron sources, modeling is an important component in establishing this efficiency and time structure. This report describes the NeutronSTARS array, which was designed and commissioned during this project. It also describes the surrogate reaction technique, specifically referencing a 235U(n,2n) commissioning measurement that was fielded during the past year. Advanced multiplicity analysis techniques have been developed for this work, which should allow for efficient analysis of 241Pu(n,2n) and 239Pu(n,2n) cross section measurements« less

Pipelined CPU Design with FPGA in Teaching Computer Architecture

ERIC Educational Resources Information Center

Lee, Jong Hyuk; Lee, Seung Eun; Yu, Heon Chang; Suh, Taeweon

2012-01-01

This paper presents a pipelined CPU design project with a field programmable gate array (FPGA) system in a computer architecture course. The class project is a five-stage pipelined 32-bit MIPS design with experiments on the Altera DE2 board. For proper scheduling, milestones were set every one or two weeks to help students complete the project on…

Next Generation Astronomical Data Processing using Big Data Technologies from the Apache Software Foundation

NASA Astrophysics Data System (ADS)

Mattmann, Chris

2014-04-01

In this era of exascale instruments for astronomy we must naturally develop next generation capabilities for the unprecedented data volume and velocity that will arrive due to the veracity of these ground-based sensor and observatories. Integrating scientific algorithms stewarded by scientific groups unobtrusively and rapidly; intelligently selecting data movement technologies; making use of cloud computing for storage and processing; and automatically extracting text and metadata and science from any type of file are all needed capabilities in this exciting time. Our group at NASA JPL has promoted the use of open source data management technologies available from the Apache Software Foundation (ASF) in pursuit of constructing next generation data management and processing systems for astronomical instruments including the Expanded Very Large Array (EVLA) in Socorro, NM and the Atacama Large Milimetre/Sub Milimetre Array (ALMA); as well as for the KAT-7 project led by SKA South Africa as a precursor to the full MeerKAT telescope. In addition we are funded currently by the National Science Foundation in the US to work with MIT Haystack Observatory and the University of Cambridge in the UK to construct a Radio Array of Portable Interferometric Devices (RAPID) that will undoubtedly draw from the rich technology advances underway. NASA JPL is investing in a strategic initiative for Big Data that is pulling in these capabilities and technologies for astronomical instruments and also for Earth science remote sensing. In this talk I will describe the above collaborative efforts underway and point to solutions in open source from the Apache Software Foundation that can be deployed and used today and that are already bringing our teams and projects benefits. I will describe how others can take advantage of our experience and point towards future application and contribution of these tools.

The near-source strong-motion accelerograms recorded by an experimental array in Tangshan, China

USGS Publications Warehouse

Peng, K.; Xie, Lingtian; Li, S.; Boore, D.M.; Iwan, W.D.; Teng, T.L.

1985-01-01

A joint research project on strong-motion earthquake studies between the People's Republic of China and the United States is in progress. As a part of this project, an experimental strong-motion array, consisting of twelve Kinemetrics PDR-1 Digital Event Recorders, was deployed in the meizoseismal area of the Ms = 7.8 Tangshan earthquake of July 28, 1976. These instruments have automatic gain ranging, a specified dynamic range of 102 dB, a 2.5 s pre-event memory, programmable triggering, and are equipped with TCG-1B Time Code Generators with a stability of 3 parts in 107 over a range of 0-50??C. In 2 y of operation beginning July, 1982 a total of 603 near-source 3-component accelerograms were gathered from 243 earthquakes of magnitude ML = 1.2-5.3. Most of these accelerograms have recorded the initial P-wave. The configuration of the experimental array and a representative set of near-source strong-motion accelerograms are presented in this paper. The set of accelerograms exhibited were obtained during the ML = 5.3 Lulong earthquake of October 19, 1982, when digital event recorders were triggered. The epicentral distances ranged from 4 to 41 km and the corresponding range of peak horizontal accelerations was 0.232g to 0.009g. A preliminary analysis of the data indicates that compared to motions in the western United States, the peak acceleration attenuates much more rapidly in the Tangshan area. The scaling of peak acceleration with magnitude, however, is similar in the two regions. Data at more distant sites are needed to confirm the more rapid attenuation. ?? 1985.

78 FR 5797 - Missisquoi Associates; Notice of Application for Amendment of License and Soliciting Comments...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-28

... to allow its affiliate, EGP Solar 1, LLC, to construct and maintain a 2.2 megawatt solar photovoltaic... solar array would be constructed on both sides of Heather Lane (the project's access road), but public... be used for the solar array is currently devoid of trees, although some grading and tree cutting is...

Phase 1 of the automated array assembly task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Pryor, R. A.; Grenon, L. A.; Coleman, M. G.

1978-01-01

The results of a study of process variables and solar cell variables are presented. Interactions between variables and their effects upon control ranges of the variables are identified. The results of a cost analysis for manufacturing solar cells are discussed. The cost analysis includes a sensitivity analysis of a number of cost factors.

Sunlight-Driven Hydrogen Formation by Membrane-Supported Photoelectrochemical Water Splitting

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

Lewis, Nathan S.

2014-03-26

This report describes the significant advances in the development of the polymer-supported photoelectrochemical water-splitting system that was proposed under DOE grant number DE-FG02-05ER15754. We developed Si microwire-array photoelectrodes, demonstrated control over the material and light-absorption properties of the microwire-array photoelectrodes, developed inexpensive processes for synthesizing the arrays, and doped the arrays p-type for use as photocathodes. We also developed techniques for depositing metal-nanoparticle catalysts of the hydrogen-evolution reaction (HER) on the wire arrays, investigated the stability and catalytic performance of the nanoparticles, and demonstrated that Ni-Mo alloys are promising earth-abundant catalysts of the HER. We also developed methods that allowmore » reuse of the single-crystalline Si substrates used for microwire growth and methods of embedding the microwire photocathodes in plastic to enable large-scale processing and deployment of the technology. Furthermore we developed techniques for controlling the structure of WO3 films, and demonstrated that structural control can improve the quantum yield of photoanodes. Thus, by the conclusion of this project, we demonstrated significant advances in the development of all components of a sunlight-driven membrane-supported photoelectrochemical water-splitting system. This final report provides descriptions of some of the scientific accomplishments that were achieved under the support of this project and also provides references to the peer-reviewed publications that resulted from this effort.« less

A project based on multi-configuration Dirac-Fock calculations for plasma spectroscopy

NASA Astrophysics Data System (ADS)

Comet, M.; Pain, J.-C.; Gilleron, F.; Piron, R.

2017-09-01

We present a project dedicated to hot plasma spectroscopy based on a Multi-Configuration Dirac-Fock (MCDF) code, initially developed by J. Bruneau. The code is briefly described and the use of the transition state method for plasma spectroscopy is detailed. Then an opacity code for local-thermodynamic-equilibrium plasmas using MCDF data, named OPAMCDF, is presented. Transition arrays for which the number of lines is too large to be handled in a Detailed Line Accounting (DLA) calculation can be modeled within the Partially Resolved Transition Array method or using the Unresolved Transition Arrays formalism in jj-coupling. An improvement of the original Partially Resolved Transition Array method is presented which gives a better agreement with DLA computations. Comparisons with some absorption and emission experimental spectra are shown. Finally, the capability of the MCDF code to compute atomic data required for collisional-radiative modeling of plasma at non local thermodynamic equilibrium is illustrated. In addition to photoexcitation, this code can be used to calculate photoionization, electron impact excitation and ionization cross-sections as well as autoionization rates in the Distorted-Wave or Close Coupling approximations. Comparisons with cross-sections and rates available in the literature are discussed.

Piezo-Phototronic Enhanced UV Sensing Based on a Nanowire Photodetector Array.

PubMed

Han, Xun; Du, Weiming; Yu, Ruomeng; Pan, Caofeng; Wang, Zhong Lin

2015-12-22

A large array of Schottky UV photodetectors (PDs) based on vertical aligned ZnO nanowires is achieved. By introducing the piezo-phototronic effect, the performance of the PD array is enhanced up to seven times in photoreponsivity, six times in sensitivity, and 2.8 times in detection limit. The UV PD array may have applications in optoelectronic systems, adaptive optical computing, and communication. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phenological Parameters Estimation Tool

NASA Technical Reports Server (NTRS)

McKellip, Rodney D.; Ross, Kenton W.; Spruce, Joseph P.; Smoot, James C.; Ryan, Robert E.; Gasser, Gerald E.; Prados, Donald L.; Vaughan, Ronald D.

2010-01-01

The Phenological Parameters Estimation Tool (PPET) is a set of algorithms implemented in MATLAB that estimates key vegetative phenological parameters. For a given year, the PPET software package takes in temporally processed vegetation index data (3D spatio-temporal arrays) generated by the time series product tool (TSPT) and outputs spatial grids (2D arrays) of vegetation phenological parameters. As a precursor to PPET, the TSPT uses quality information for each pixel of each date to remove bad or suspect data, and then interpolates and digitally fills data voids in the time series to produce a continuous, smoothed vegetation index product. During processing, the TSPT displays NDVI (Normalized Difference Vegetation Index) time series plots and images from the temporally processed pixels. Both the TSPT and PPET currently use moderate resolution imaging spectroradiometer (MODIS) satellite multispectral data as a default, but each software package is modifiable and could be used with any high-temporal-rate remote sensing data collection system that is capable of producing vegetation indices. Raw MODIS data from the Aqua and Terra satellites is processed using the TSPT to generate a filtered time series data product. The PPET then uses the TSPT output to generate phenological parameters for desired locations. PPET output data tiles are mosaicked into a Conterminous United States (CONUS) data layer using ERDAS IMAGINE, or equivalent software package. Mosaics of the vegetation phenology data products are then reprojected to the desired map projection using ERDAS IMAGINE

A Comparison of Global Indexing Schemes to Facilitate Earth Science Data Management

NASA Astrophysics Data System (ADS)

Griessbaum, N.; Frew, J.; Rilee, M. L.; Kuo, K. S.

2017-12-01

Recent advances in database technology have led to systems optimized for managing petabyte-scale multidimensional arrays. These array databases are a good fit for subsets of the Earth's surface that can be projected into a rectangular coordinate system with acceptable geometric fidelity. However, for global analyses, array databases must address the same distortions and discontinuities that apply to map projections in general. The array database SciDB supports enormous databases spread across thousands of computing nodes. Additionally, the following SciDB characteristics are particularly germane to the coordinate system problem: SciDB efficiently stores and manipulates sparse (i.e. mostly empty) arrays. SciDB arrays have 64-bit indexes. SciDB supports user-defined data types, functions, and operators. We have implemented two geospatial indexing schemes in SciDB. The simplest uses two array dimensions to represent longitude and latitude. For representation as 64-bit integers, the coordinates are multiplied by a scale factor large enough to yield an appropriate Earth surface resolution (e.g., a scale factor of 100,000 yields a resolution of approximately 1m at the equator). Aside from the longitudinal discontinuity, the principal disadvantage of this scheme is its fixed scale factor. The second scheme uses a single array dimension to represent the bit-codes for locations in a hierarchical triangular mesh (HTM) coordinate system. A HTM maps the Earth's surface onto an octahedron, and then recursively subdivides each triangular face to the desired resolution. Earth surface locations are represented as the concatenation of an octahedron face code and a quadtree code within the face. Unlike our integerized lat-lon scheme, the HTM allow for objects of different size (e.g., pixels with differing resolutions) to be represented in the same indexing scheme. We present an evaluation of the relative utility of these two schemes for managing and analyzing MODIS swath data.

Determination of hot-spot susceptibility of multistring photovoltaic modules in a central-station application

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.; Weaver, R. W.; Ross, R. G., Jr.; Spencer, R.; Arnett, J. C.

1984-01-01

Part of the effort of the Jet Propulsion Laboratory (JPL) Flat-Plate Solar Array Project (FSA) includes a program to improve module and array reliability. A collaborative activity with industry dealing with the problem of hot-spot heating due to the shadowing of photovoltaic cells in modules and arrays containing several paralleled cell strings is described. The use of multiparallel strings in large central-station arrays introduces the likelihood of unequal current sharing and increased heating levels. Test results that relate power dissipated, current imbalance, cross-strapping frequency, and shadow configuration to hot-spot heating levels are presented. Recommendations for circuit design configurations appropriate to central-station applications that reduce the risk of hot-spot problems are offered. Guidelines are provided for developing hot-spot tests for arrays when current imbalance is a threat.

Project Hyreus: Mars Sample Return Mission Utilizing in Situ Propellant Production

NASA Technical Reports Server (NTRS)

Bruckner, A. P.; Thill, Brian; Abrego, Anita; Koch, Amber; Kruse, Ross; Nicholson, Heather; Nill, Laurie; Schubert, Heidi; Schug, Eric; Smith, Brian

1993-01-01

Project Hyreus is an unmanned Mars sample return mission that utilizes propellants manufactured in situ from the Martian atmosphere for the return voyage. A key goal of the mission is to demonstrate the considerable benefits of using indigenous resources and to test the viability of this approach as a precursor to manned Mars missions. The techniques, materials, and equipment used in Project Hyreus represent those that are currently available or that could be developed and readied in time for the proposed launch date in 2003. Project Hyreus includes such features as a Mars-orbiting satellite equipped with ground-penetrating radar, a large rover capable of sample gathering and detailed surface investigations, and a planetary science array to perform on-site research before samples are returned to Earth. Project Hyreus calls for the Mars Landing Vehicle to land in the Mangala Valles region of Mars, where it will remain for approximately 1.5 years. Methane and oxygen propellant for the Earth return voyage will be produced using carbon dioxide from the Martian atmosphere and a small supply of hydrogen brought from Earth. This process is key to returning a large Martian sample to Earth with a single Earth launch.

Project Hyreus: Mars sample return mission utilizing in situ propellant production

NASA Technical Reports Server (NTRS)

Abrego, Anita; Bair, Chris; Hink, Anthony; Kim, Jae; Koch, Amber; Kruse, Ross; Ngo, Dung; Nicholson, Heather; Nill, Laurie; Perras, Craig

1993-01-01

Project Hyreus is an unmanned Mars sample return mission that utilizes propellants manufactured in situ from the Martian atmosphere for the return voyage. A key goal of the mission is to demonstrate the considerable benefits of using indigenous resources and to test the viability of this approach as a precursor to manned Mars missions. The techniques, materials, and equipment used in Project Hyreus represent those that are currently available or that could be developed and readied in time for the proposed launch date in 2003. Project Hyreus includes such features as a Mars-orbiting satellite equipped with ground-penetrating radar, a large rover capable of sample gathering and detailed surface investigations, and a planetary science array to perform on-site research before samples are returned to Earth. Project Hyreus calls for the Mars Landing Vehicle to land in the Mangala Valles region of Mars, where it will remain for approximately 1.5 years. Methane and oxygen propellant for the Earth return voyage will be produced using carbon dioxide from the Martian atmosphere and a small supply of hydrogen brought from Earth. This process is key to returning a large Martian sample to Earth with a single Earth launch.

SU-E-U-02: The Development of a Practical Ultrasonic System for Cross-Sectional Imaging of Small Animals

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

Kamp, J; Karmanos Cancer Institute - International Imaging Center, Detroit, MI; Malyarenko, E

Purpose: To test the feasibility of developing a practical medium frequency ultrasound tomography method for small animal imaging. The ability to produce cross-sectional or full body images of a live small animal using a low-cost tabletop ultrasound scanner without any special license would be very beneficial to long term biological studies, where repeated scanning is often required over an extended period of time. Methods: The cross sectional images were produced by compounding multiple B-scans of a laboratory phantom or an animal acquired at different projection angles. Two imaging systems were used to test the concept. The first system included amore » programmable 64-channel phased array controller driving a 128-channel, 5–10 MHz linear probe to produce 143 B-Mode projections of the spinning object. The second system designed and manufactured in house, produced 64 or 128 B-Mode projections with a single unfocused 8 MHz transducer scanning with a 0.116 mm step size. Results: The phased array system provided good penetration through the phantoms/mice (with the exception of the lungs) and allowed to acquire data in a very short time. The cross-sectional images have enough resolution and dynamic range to detect both high- and low-contrast organs. The single transducer system takes longer to scan, and the data require more sophisticated processing. To date, our images allow seeing details as small as 1–2 mm in the phantoms and in small animals, with the contrast mostly due to highly reflecting bones and air inclusions. Conclusion: The work indicates that very detailed and anatomically correct images can be created by relatively simple and inexpensive means. With more advanced algorithms and improved system design, scan time can be reduced considerably, enabling high-resolution full 3D imaging. This will allow for quick and easy scans that can help monitor tumor growth and/or regression without contributing any dose to the animal. The authors would like to acknowledge the financial and engineering support from Tessonics.« less

Engineering Technical Support Center Annual Report Fiscal Year 2014; Technical Support and Innovative Research for Contaminated Sites

EPA Science Inventory

This report highlights significant projects that the ETSC has supported throughout fiscal year 2014. Projects have addressed an array of environmental scenarios, including but not limited to remote mining contamination, expansive landfill waste, sediment remediation by capping, ...

The Market Linkage Project for Special Education: A Project Update.

ERIC Educational Resources Information Center

Bulford, Sally; Daniels, Carol

1982-01-01

The procedure for marketing special education materials developed by government money is detailed, and the array of technical assistance activities offered by LINC Resources is described. Material criteria is considered in terms of such aspects as timeliness, target audiences, effectiveness data, and product format. (CL)

Multiteide Project: Multiparametric characterization of the activity of Teide-Pico Viejo volcanic system

NASA Astrophysics Data System (ADS)

Domínguez Cerdeña, Itahiza; Villasante-Marcos, Victor; Meletlidis, Stavros; Sainz-Maza, Sergio; Abella, Rafael; Torres, Pedro A.; Sánchez, Nieves; Luengo-Oroz, Natividad; José Blanco, María; García-Cañada, Laura; Pereda de Pablo, Jorge; Lamolda, Héctor; Moure, David; Del Fresno, Carmen; Finizola, Anthony; Felepto, Alicia

2017-04-01

Teide-Pico Viejo complex stands for one of the major natural volcanic hazards in the Canary Islands, due to the expected types of eruptions in the area and the high number of inhabitants in Tenerife Island. Therefore, it is necessary to have a volcanic alert system able to afford a precise assessment of the current state of the complex. For this purpose, the knowledge of the expected signals at each volcanic activity level is required. Moreover, the external effects that can affect the measurements shall be distinguished, external influences as the atmosphere are qualitatively known but have not been quantified yet. The objective of the project is to collect, analyze and jointly and continuously evaluate over time geophysical, geodetic, geochemical and meteorological data from the Teide-Pico Viejo complex and its surroundings. A continuous multiparametric network have been deployed in the area, which, together with the data provided by the Volcano Monitoring Network of the Instituto Geográfico Nacional (IGN) and data from other institutions will provide a comprehensive set of data with high resolution in both space and time. This multiparametric network includes a seismic array, two self-potential lines for continuous measurements, five magnetometers and two weather stations. The network will be complemented with 8 CGPS stations, one tiltmeter, 10 seismic stations, and four thermometric stations on the fumaroles of Teide volcano that IGN already manage in Tenerife. The data will be completed with the results from different repeated surveys of self potential, soil temperature and CO2 diffuse flux in several pre-established areas on top of Teide throughout the entire duration of project. During the project, new computation tools will be developed to study the correlation between the different parameters analyzed. The results obtained will characterize the possible seasonal fluctuations of each parameter and the variations related to meteorological phenomena. In addition, they will allow identifying the response of all the analyzed parameters to specific events that are traditionally studied with a single technique, such as short episodes of tremor (sporadically registered in Teide-Pico Viejo surroundings) or changes in activity of the hydrothermal system of the volcanic complex. We present here the first multiparametric results obtained from the project, including locations with the seismic array, CO2 and temperature maps of Teide fumaroles zones and magnetometric measurements.

Pellet inspection apparatus

DOEpatents

Wilks, Robert S.; Taleff, Alexander; Sturges, Jr., Robert H.

1982-01-01

Apparatus for inspecting nuclear fuel pellets in a sealed container for diameter, flaws, length and weight. The apparatus includes, in an array, a pellet pick-up station, four pellet inspection stations and a pellet sorting station. The pellets are delivered one at a time to the pick-up station by a vibrating bowl through a vibrating linear conveyor. Grippers each associated with a successive pair of the stations are reciprocable together to pick up a pellet at the upstream station of each pair and to deposit the pellet at the corresponding downstream station. The gripper jaws are opened selectively depending on the state of the pellets at the stations and the particular cycle in which the apparatus is operating. Inspection for diameter, flaws and length is effected in each case by a laser beam projected on the pellets by a precise optical system while each pellet is rotated by rollers. Each laser and its optical system are mounted in a container which is free standing on a precise surface and is provided with locating buttons which engage locating holes in the surface so that each laser and its optical system is precisely set. The roller stands are likewise free standing and are similarly precisely positioned. The diameter optical system projects a thin beam of light which scans across the top of each pellet and is projected on a diode array. The fl GOVERNMENT CONTRACT CLAUSE The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of Energy bearing No. EY-67-14-C-2170.

Interferometric imaging of the San Andreas Fault at Parkfield Using a Massive VSP

NASA Astrophysics Data System (ADS)

Chavarria, J.; Goertz, A.; Karrenbach, M.; Paulsson, B.

2006-12-01

The San Andreas Fault Observatory at Depth (SAFOD) has the goal of investigating the physical processes controlling earthquakes in central California at Parkfield. The observatory consists of a deep well, that intersected the San Andreas Fault at seismogenic depths of ~3.2 km, where recurring microearthquake activity takes place. Previous to the drilling of Phase II, that intersected the fault at the end of Summer 2005, a long array of seismometers was deployed in the deeper part of the well to characterize the fault structure and to aid the monitoring activities of the natural seismicity. The Massive VSP array consisted of 80 three component seismometers that were deployed during April and May 2005. During this period of time we recorded active data from 13 explosions used to refine the velocity models that improved the locations of target events. In addition to this, we continuously monitored passive data from the natural earthquake activity in the area that was dominated by the Parkfield 2004 event aftershock sequence. During the recording time of this project we were able to record one of the target earthquakes of the SAFOD project as well as recently discovered non-volcanic tremor. The data recorded by this deep array of seismometers has provided important information to characterize the structure of the fault at scale that is comparable to the scale of the geologic observations. These observations, derived during drilling of the well, consist of cores and cuttings as well as geophysical logs. With the use of the borehole array of seismometers we have been able to directly correlate this lithologic information with seismic phases observed in the VSP data. This has lead to better understanding the nature of the scattering that takes place in this complex fault zone. Seismic reflections in the dataset were analyzed with Kirchhoff imaging methods to determine a partial image of the San Andreas Fault at depth. Due to the low density distribution of sources in the study area the illumination volume is limited but still shows clear signals originating from sub-vertical structures associated to the strands of the San Andreas fault inferred from high resolution earthquake location. The existing Kirchhoff imaging methods have been complemented with the use of interferometric imaging by which we extract the Green's function of the data recorded by the array. This takes place with the use of correlation analysis of both active and passive data resulting in a dataset where each downhole receiver acts as a virtual source. This analysis has provided a refined image of the structure of the San Andreas Fault at seismogenic depths with which a better understanding of the system can be achieved.

SIMBIOS Project

NASA Technical Reports Server (NTRS)

Fargion, Giulietta S.; McClain, Charles R.

2002-01-01

The purpose of this technical report is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities, NASA Research Announcement (NRA) research status, satellite data processing, data product validation, and field calibration. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of validating and combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational project. The SIMBIOS Science Team Principal Investigators' (PIs) original contributions to this report are in chapters four and above. The purpose of these contributions is to describe the current research status of the SIMBIOS-NRA-96 funded research. The contributions are published as submitted, with the exception of minor edits to correct obvious grammatical or clerical errors.

EEE - Extreme Energy Events: an astroparticle physics experiment in Italian High Schools

NASA Astrophysics Data System (ADS)

Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Bressan, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferrarov, A.; Forster, R.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Maggiora, A.; Maron, G.; Mazziotta, M. N.; Miozzi, S.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Rodriguez Rodriguez, A.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Taiuti, M.; Terreni, G.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

2016-05-01

The Extreme Energy Events project (EEE) is aimed to study Extensive Air Showers (EAS) from primary cosmic rays of more than 1018 eV energy detecting the ground secondary muon component using an array of telescopes with high spatial and time resolution. The second goal of the EEE project is to involve High School teachers and students in this advanced research work and to initiate them in scientific culture: to reach both purposes the telescopes are located inside High School buildings and the detector construction, assembling and monitoring - together with data taking and analysis - are done by researchers from scientific institutions in close collaboration with them. At present there are 42 telescopes in just as many High Schools scattered all over Italy, islands included, plus two at CERN and three in INFN units. We report here some preliminary physics results from the first two common data taking periods together with the outreach impact of the project.

Efficient Cells Cut the Cost of Solar Power

NASA Technical Reports Server (NTRS)

2013-01-01

If you visit Glenn Research Center, you might encounter a photovoltaic (PV) array that looks unlike anything you've ever seen. In fact, what one would normally identify as the panel is actually a series of curved mirrors called solar concentrators, engineered to reflect sunlight rather than absorb it. These concentrators gather, intensify, and focus sun beams upward, aiming at a fixture containing specialized silicon concentrated PV chips the actual solar cells. If you stay by the array for a while, you'll notice that the solar concentrators follow the path of the sun throughout the day, changing position to best capture and utilize the sunlight. The specialized chips that make the technology possible are the brainchild of Bernard Sater, an engineer who had worked at Glenn since the early 1960s before retiring to pursue his unique ideas for harnessing solar power. Sater contributed to multiple PV projects in the latter part of his career at the Center, including research and development on the International Space Station s solar arrays. In his spare time, he enjoyed tinkering with new approaches to solar power, experiments that resulted in the system installed at Glenn today. Sater s basic idea had two components. First, he wanted to create a silicon cell that was smaller, more efficient, and much lower cost than those available at the time. To ensure that the potential of such a chip could be realized, he also planned on pairing it with a system that could concentrate sunlight and focus it directly on the cell. When he retired from Glenn in 1994 to focus on researching and developing the technology full time, Sater found that NASA was interested in the concept and ready to provide funding, facilities, and expertise in order to assist in its development.

Tracking interstellar space weather toward timing-array millisecond pulsars

NASA Astrophysics Data System (ADS)

Bhat, N. D. R.; Ord, S. M.; Tremblay, S. E.; Shannon, R. M.; van Straten, W.; Kaplan, D. L.; Macquart, J.-P.; Kirsten, F.

2016-07-01

Recent LIGO detection of milli-Hertz gravitational wave (GW) signals from a black-hole merger event has further reinforced the important role of Pulsar timing array (PTA) experiments in the GW astronomy. PTAs exploit the clock-like stability of fast-spinning millisecond pulsars (MSPs) to make a direct detection of ultra-low frequency (nano-Hertz) gravitational waves. The science enabled by PTAs is thus highly complementary to that possible by LIGO-like detectors. PTAs are also a key science objective for the SKA. PTA efforts over the past few years suggest that interstellar propagation effects on pulsar signals may ultimately limit the detection sensitivity of PTAs unless they are accurately measured and corrected for in timing measurements. Interstellar medium (ISM) effects are much stronger at lower radio frequencies and therefore the MWA presents an exciting and unique opportunity to calibrate interstellar propagation delays. This will potentially lead to enhanced sensitivity and scientific impact of PTA projects. Since our first demonstration of ability to form a coherent (tied-array) beam by reprocessing the recorded VCS data (Bhat et al. 2016), we have successfully ported the full processing chain to the Galaxy cluster of Pawsey and demonstrated the value of high-sensitivity multi-band pulsar observations that are now possible with the MWA. Here we propose further observations of two most promising PTA pulsars that will be nightly objects in the 2016B period. Our main science driver is to characterise the nature of the turbulent ISM through high-quality scintillation and dispersion studies including the investigation of chromatic (frequency-dependent) DMs. Success of these efforts will define the breadth and scope of a more ambitious program in the future, bringing in a new science niche for the MWA and SKA-low.

A Phase Correction Technique Based on Spatial Movements of Antennas in Real-Time (S.M.A.R.T.) for Designing Self-Adapting Conformal Array Antennas

NASA Astrophysics Data System (ADS)

Roy, Sayan

This research presents a real-time adaptive phase correction technique for flexible phased array antennas on conformal surfaces of variable shapes. Previously reported pattern correctional methods for flexible phased array antennas require prior knowledge on the possible non-planar shapes in which the array may adapt for conformal applications. For the first time, this initial requirement of shape curvature knowledge is no longer needed and the instantaneous information on the relative location of array elements is used here for developing a geometrical model based on a set of Bezier curves. Specifically, by using an array of inclinometer sensors and an adaptive phase-correctional algorithm, it has been shown that the proposed geometrical model can successfully predict different conformal orientations of a 1-by-4 antenna array in real-time without the requirement of knowing the shape-changing characteristics of the surface the array is attached upon. Moreover, the phase correction technique is validated by determining the field patterns and broadside gain of the 1-by-4 antenna array on four different conformal surfaces with multiple points of curvatures. Throughout this work, measurements are shown to agree with the analytical solutions and full-wave simulations.

Synthesis of Conformal Phased Antenna Arrays With A Novel Multiobjective Invasive Weed Optimization Algorithm

NASA Astrophysics Data System (ADS)

Li, Wen Tao; Hei, Yong Qiang; Shi, Xiao Wei

2018-04-01

By virtue of the excellent aerodynamic performances, conformal phased arrays have been attracting considerable attention. However, for the synthesis of patterns with low/ultra-low sidelobes of the conventional conformal arrays, the obtained dynamic range ratios of amplitude excitations could be quite high, which results in stringent requirements on various error tolerances for practical implementation. Time-modulated array (TMA) has the advantages of low sidelobe and reduced dynamic range ratio requirement of amplitude excitations. This paper takes full advantages of conformal antenna arrays and time-modulated arrays. The active-element-pattern, including element mutual coupling and platform effects, is employed in the whole design process. To optimize the pulse durations and the switch-on instants of the time-modulated elements, multiobjective invasive weed optimization (MOIWO) algorithm based on the nondominated sorting of the solutions is proposed. A S-band 8-element cylindrical conformal array is designed and a S-band 16-element cylindrical-parabolic conformal array is constructed and tested at two different steering angles.

Real time interrogation technique for fiber Bragg grating enhanced fiber loop ringdown sensors array.

PubMed

Zhang, Yunlong; Li, Ruoming; Shi, Yuechun; Zhang, Jintao; Chen, Xiangfei; Liu, Shengchun

2015-06-01

A novel fiber Bragg grating aided fiber loop ringdown (FLRD) sensor array and the wavelength-time multiplexing based interrogation technique for the FLRD sensors array are proposed. The interrogation frequency of the system is formulated and the interrelationships among the parameters of the system are analyzed. To validate the performance of the proposed system, a five elements array is experimentally demonstrated, and the system shows the capability of real time monitoring every FLRD element with interrogation frequency of 125.5 Hz.

A hyperspectral image projector for hyperspectral imagers

NASA Astrophysics Data System (ADS)

Rice, Joseph P.; Brown, Steven W.; Neira, Jorge E.; Bousquet, Robert R.

2007-04-01

We have developed and demonstrated a Hyperspectral Image Projector (HIP) intended for system-level validation testing of hyperspectral imagers, including the instrument and any associated spectral unmixing algorithms. HIP, based on the same digital micromirror arrays used in commercial digital light processing (DLP*) displays, is capable of projecting any combination of many different arbitrarily programmable basis spectra into each image pixel at up to video frame rates. We use a scheme whereby one micromirror array is used to produce light having the spectra of endmembers (i.e. vegetation, water, minerals, etc.), and a second micromirror array, optically in series with the first, projects any combination of these arbitrarily-programmable spectra into the pixels of a 1024 x 768 element spatial image, thereby producing temporally-integrated images having spectrally mixed pixels. HIP goes beyond conventional DLP projectors in that each spatial pixel can have an arbitrary spectrum, not just arbitrary color. As such, the resulting spectral and spatial content of the projected image can simulate realistic scenes that a hyperspectral imager will measure during its use. Also, the spectral radiance of the projected scenes can be measured with a calibrated spectroradiometer, such that the spectral radiance projected into each pixel of the hyperspectral imager can be accurately known. Use of such projected scenes in a controlled laboratory setting would alleviate expensive field testing of instruments, allow better separation of environmental effects from instrument effects, and enable system-level performance testing and validation of hyperspectral imagers as used with analysis algorithms. For example, known mixtures of relevant endmember spectra could be projected into arbitrary spatial pixels in a hyperspectral imager, enabling tests of how well a full system, consisting of the instrument + calibration + analysis algorithm, performs in unmixing (i.e. de-convolving) the spectra in all pixels. We discuss here the performance of a visible prototype HIP. The technology is readily extendable to the ultraviolet and infrared spectral ranges, and the scenes can be static or dynamic.

System Assessment of a High Power 3-U CubeSat

NASA Technical Reports Server (NTRS)

Shaw, Katie

2016-01-01

The Advanced eLectrical Bus (ALBus) CubeSat project is a technology demonstration mission of a 3-UCubeSat with an advanced, digitally controlled electrical power system capability and novel use of Shape Memory Alloy (SMA) technology for reliable deployable solar array mechanisms. The objective of the project is to, through an on orbit demonstration, advance the state of power management and distribution (PMAD) capabilities to enable future missions requiring higher power, flexible and reliable power systems. The goals of the mission include demonstration of: 100 Watt distribution to a target electrical load, efficient battery charging in the orbital environment, flexible power system distribution interfaces, adaptation of power system control on orbit, and reliable deployment of solar arrays and antennas utilizing re-settable SMA mechanisms. The power distribution function of the ALBus PMAD system is unique in the total power to target load capability of 100 W, the flexibility to support centralized or point-to-load regulation and ability to respond to fast transient power requirements. Power will be distributed from batteries at 14.8 V, 6.5 A to provide 100 W of power directly to a load. The deployable solar arrays utilize NASA Glenn Research Center superelastic and activated Nitinol(Nickel-Titanium alloy) Shape Memory Alloy (SMA) technology for hinges and a retention and release mechanism. The deployable solar array hinge design features utilization of the SMA material properties for dual purpose. The hinge uses the shape memory properties of the SMA to provide the spring force to deploy the arrays. The electrical conductivity properties of the SMA also enables the design to provide clean conduits for power transfer from the deployable arrays to the power management system. This eliminates the need for electrical harnesses between the arrays and the PMAD system in the ALBus system design. The uniqueness of the SMA retention and release mechanism design is the ability to reset the mechanism, allowing functional tests of the mechanisms prior to flight with no degradation of performance. The project is currently in preparation at the NASA Glenn Research Center for a launch in late calendar year of 2017. The 100 Watt power distribution and dual purpose, re-settable SMA mechanisms introduced several system level challenges due to the physical constraints in volume, mass and surface area of 3-U CubeSats. Several trade studies and design cycles have been completed to develop a system which supports the project objectives. This paper is a report on the results of the system level trade studies and assessments. The results include assessment of options for thermal control of 100 Watts of power dissipation, data from system analyses and engineering development tests, limitations of the 3-U system and extensibility to larger scale CubeSat missions.

Benchmark Modeling of the Near-Field and Far-Field Wave Effects of Wave Energy Arrays

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

Rhinefrank, Kenneth E; Haller, Merrick C; Ozkan-Haller, H Tuba

2013-01-26

This project is an industry-led partnership between Columbia Power Technologies and Oregon State University that will perform benchmark laboratory experiments and numerical modeling of the near-field and far-field impacts of wave scattering from an array of wave energy devices. These benchmark experimental observations will help to fill a gaping hole in our present knowledge of the near-field effects of multiple, floating wave energy converters and are a critical requirement for estimating the potential far-field environmental effects of wave energy arrays. The experiments will be performed at the Hinsdale Wave Research Laboratory (Oregon State University) and will utilize an array ofmore » newly developed Buoys' that are realistic, lab-scale floating power converters. The array of Buoys will be subjected to realistic, directional wave forcing (1:33 scale) that will approximate the expected conditions (waves and water depths) to be found off the Central Oregon Coast. Experimental observations will include comprehensive in-situ wave and current measurements as well as a suite of novel optical measurements. These new optical capabilities will include imaging of the 3D wave scattering using a binocular stereo camera system, as well as 3D device motion tracking using a newly acquired LED system. These observing systems will capture the 3D motion history of individual Buoys as well as resolve the 3D scattered wave field; thus resolving the constructive and destructive wave interference patterns produced by the array at high resolution. These data combined with the device motion tracking will provide necessary information for array design in order to balance array performance with the mitigation of far-field impacts. As a benchmark data set, these data will be an important resource for testing of models for wave/buoy interactions, buoy performance, and far-field effects on wave and current patterns due to the presence of arrays. Under the proposed project we will initiate high-resolution (fine scale, very near-field) fluid/structure interaction simulations of buoy motions, as well as array-scale, phase-resolving wave scattering simulations. These modeling efforts will utilize state-of-the-art research quality models, which have not yet been brought to bear on this complex problem of large array wave/structure interaction problem.« less

Next Generation Polar Seismic Instrumentation Challenges

NASA Astrophysics Data System (ADS)

Parker, T.; Beaudoin, B. C.; Gridley, J.; Anderson, K. R.

2011-12-01

Polar region logistics are the limiting factor for deploying deep field seismic arrays. The IRIS PASSCAL Instrument Center, in collaboration with UNAVCO, designed and deployed several systems that address some of the logistical constraints of polar deployments. However, continued logistics' pressures coupled with increasingly ambitious science projects require further reducing the logistics required for deploying both summer and over winter stations. Our focus is to reduce station power requirements and bulk, thereby minimizing the time and effort required to deploy these arrays. We will reduce the weight of the battery bank by incorporating the most applicable new high energy-density battery technology. Using these batteries will require a completely new power management system along with an appropriate smart enclosure. The other aspect will be to integrate the digitizing system with the sensor. Both of these technologies should reduce the install time and shipping volume plus weight while reducing some instrument costs. We will also continue work on an effective Iridium telemetry solution for automated data return. The costs and limitations of polar deep-field science easily justifies a specialized development effort but pays off doubly in that we will continue to leverage the advancements in reduced logistics and increased performance for the benefit of low-latitude seismic research.

High spatiotemporal resolution monitoring of hydrological function across degraded peatlands in the south west UK.

NASA Astrophysics Data System (ADS)

Ashe, Josie; Luscombe, David; Grand-Clement, Emilie; Gatis, Naomi; Anderson, Karen; Brazier, Richard

2014-05-01

The Exmoor/Dartmoor Mires Project is a peatland restoration programme focused on the geoclimatically marginal blanket bogs of South West England. In order to better understand the hydrological functioning of degraded/restored peatlands and support land management decisions across these uplands, this study is providing robust spatially distributed, hydrological monitoring at a high temporal resolution and in near real time. This paper presents the conceptual framework and experimental design for three hydrological monitoring arrays situated in headwater catchments dominated by eroding and drained blanket peatland. Over 250 individual measurements are collected at a high temporal resolution (15 minute time-step) via sensors integrated within a remote telemetry system. These are sent directly to a dedicated server over VHF and GPRS mobile networks. Sensors arrays are distributed at varying spatial scales throughout the studied catchments and record multiple parameters including: water table depth, channel flow, temperature, conductivity and pH measurements. A full suite of meteorological sensors and ten spatially distributed automatic flow based water samplers are also connected to the telemetry system and controlled remotely. This paper will highlight the challenges and solutions to obtaining these data in exceptionally remote and harsh field conditions over long (multi annual) temporal scales.

Locating Microseism Sources Using Spurious Arrivals in Intercontinental Noise Correlations

NASA Astrophysics Data System (ADS)

Retailleau, Lise; Boué, Pierre; Stehly, Laurent; Campillo, Michel

2017-10-01

The accuracy of Green's functions retrieved from seismic noise correlations in the microseism frequency band is limited by the uneven distribution of microseism sources at the surface of the Earth. As a result, correlation functions are often biased as compared to the expected Green's functions, and they can include spurious arrivals. These spurious arrivals are seismic arrivals that are visible on the correlation and do not belong to the theoretical impulse response. In this article, we propose to use Rayleigh wave spurious arrivals detected on correlation functions computed between European and United States seismic stations to locate microseism sources in the Atlantic Ocean. We perform a slant stack on a time distance gather of correlations obtained from an array of stations that comprises a regional deployment and a distant station. The arrival times and the apparent slowness of the spurious arrivals lead to the location of their source, which is obtained through a grid search procedure. We discuss improvements in the location through this methodology as compared to classical back projection of microseism energy. This method is interesting because it only requires an array and a distant station on each side of an ocean, conditions that can be met relatively easily.

Earth science big data at users' fingertips: the EarthServer Science Gateway Mobile

NASA Astrophysics Data System (ADS)

Barbera, Roberto; Bruno, Riccardo; Calanducci, Antonio; Fargetta, Marco; Pappalardo, Marco; Rundo, Francesco

2014-05-01

The EarthServer project (www.earthserver.eu), funded by the European Commission under its Seventh Framework Program, aims at establishing open access and ad-hoc analytics on extreme-size Earth Science data, based on and extending leading-edge Array Database technology. The core idea is to use database query languages as client/server interface to achieve barrier-free "mix & match" access to multi-source, any-size, multi-dimensional space-time data -- in short: "Big Earth Data Analytics" - based on the open standards of the Open Geospatial Consortium Web Coverage Processing Service (OGC WCPS) and the W3C XQuery. EarthServer combines both, thereby achieving a tight data/metadata integration. Further, the rasdaman Array Database System (www.rasdaman.com) is extended with further space-time coverage data types. On server side, highly effective optimizations - such as parallel and distributed query processing - ensure scalability to Exabyte volumes. In this contribution we will report on the EarthServer Science Gateway Mobile, an app for both iOS and Android-based devices that allows users to seamlessly access some of the EarthServer applications using SAML-based federated authentication and fine-grained authorisation mechanisms.

Assessing Multiple Methods for Determining Active Source Travel Times in a Dense Array

NASA Astrophysics Data System (ADS)

Parker, L.; Zeng, X.; Thurber, C. H.; Team, P.

2016-12-01

238 three-component nodal seismometers were deployed at the Brady Hot Springs geothermal field in Nevada to characterize changes in the subsurface as a result of changes in pumping conditions. The array consisted of a 500 meter by 1600 meter irregular grid with 50 meter spacing centered in an approximately rectangular 1200 meter by 1600 meter grid with 200 meter spacing. A large vibroseis truck (T-Rex) was deployed as an active seismic source at 216 locations. Over the course of 15 days, the truck occupied each location up to four times. At each location a swept-frequency source between 5 and 80 Hz over 20 seconds was produced using three vibration modes: longitudinal S-wave, transverse S-wave, and P-wave. Seismic wave arrivals were identified using three methods: cross-correlation, deconvolution, and Wigner-Ville distribution (WVD) plus the Hough Transform (HT). Surface wave arrivals were clear for all three modes of vibration using all three methods. Preliminary tomographic models will be presented, using the arrivals of the identified phases. This analysis is part of the PoroTomo project: Poroelastic Tomography by Adjoint Inverse Modeling of Data from Seismology, Geodesy, and Hydrology; http://geoscience.wisc.edu/feigl/porotomo.

R classes and methods for SNP array data.

PubMed

Scharpf, Robert B; Ruczinski, Ingo

2010-01-01

The Bioconductor project is an "open source and open development software project for the analysis and comprehension of genomic data" (1), primarily based on the R programming language. Infrastructure packages, such as Biobase, are maintained by Bioconductor core developers and serve several key roles to the broader community of Bioconductor software developers and users. In particular, Biobase introduces an S4 class, the eSet, for high-dimensional assay data. Encapsulating the assay data as well as meta-data on the samples, features, and experiment in the eSet class definition ensures propagation of the relevant sample and feature meta-data throughout an analysis. Extending the eSet class promotes code reuse through inheritance as well as interoperability with other R packages and is less error-prone. Recently proposed class definitions for high-throughput SNP arrays extend the eSet class. This chapter highlights the advantages of adopting and extending Biobase class definitions through a working example of one implementation of classes for the analysis of high-throughput SNP arrays.

Heat pipe with improved wick structures

DOEpatents

Benson, David A.; Robino, Charles V.; Palmer, David W.; Kravitz, Stanley H.

2000-01-01

An improved planar heat pipe wick structure having projections formed by micromachining processes. The projections form arrays of interlocking, semi-closed structures with multiple flow paths on the substrate. The projections also include overhanging caps at their tops to increase the capillary pumping action of the wick structure. The capped projections can be formed in stacked layers. Another layer of smaller, more closely spaced projections without caps can also be formed on the substrate in between the capped projections. Inexpensive materials such as Kovar can be used as substrates, and the projections can be formed by electrodepositing nickel through photoresist masks.

Proceedings of the 21st Project Integration Meeting

NASA Technical Reports Server (NTRS)

1983-01-01

Progress made by the Flat Plate Solar Array Project during the period April 1982 to January 1983 is described. Reports on polysilicon refining, thin film solar cell and module technology development, central station electric utility activities, silicon sheet growth and characteristics, advanced photovoltaic materials, cell and processes research, module technology, environmental isolation, engineering sciences, module performance and failure analysis and project analysis and integration are included.

National Science Board Approves VLA Expansion

NASA Astrophysics Data System (ADS)

2001-11-01

The National Science Board, the governing body for the National Science Foundation (NSF), has approved an expansion project for the Very Large Array (VLA) radio telescope in New Mexico. The board recommended an NSF award of approximately 58.3 million for the project over the next decade. The action came at the Board's meeting in Washington on Nov. 15. The Very Large Array The Very Large Array "This approval means that the VLA, already the most scientifically productive ground-based telescope in all of astronomy, will remain at the cutting edge of astrophysical research through the coming decades," said Paul Vanden Bout, director of the National Radio Astronomy Observatory (NRAO). The expansion project will replace aging equipment left over from the VLA's construction during the 1970s with modern technology, improving the VLA's scientific capabilities more than tenfold. Using the existing 27 dish antennas, each weighing 230 tons, the Expanded VLA will have greatly improved ability to image distant celestial objects and to decipher the physical nature of those objects. In addition to the 58.3 million NSF allocation, the governments of Canada and Mexico plan to provide funding for the VLA expansion. The VLA Expansion Project was formally proposed to the NSF, which owns the VLA, last year. Also last year, the project received a strong endorsement from the Astronomy and Astrophysics Survey Committee of the National Research Council, the working arm of the National Academies of Sciences and Engineering. That committee had been given the task of setting nationwide priorities for astronomy spending over the next decade. The Survey Committee report listed the Expanded VLA as an important contributor to new understanding in three high-priority research areas for the next decade: studies of star and planet formation; research into black holes; and unraveling details about the "dawn of the modern universe." Dedicated in 1980, the VLA is the most powerful, flexible and widely- used radio telescope in the world. It brought dramatically-improved observational capabilities to the scientific community two decades ago, and has contributed significantly to nearly every branch of astronomy. More than 2,200 scientists have used the VLA for more than 10,000 separate observing projects. Astronomers seek more than twice as much VLA observing time than can be provided. Since the VLA's dedication, many technical improvements have made it much more capable than its original design contemplated. However, some of the technologies incorporated into the VLA during its construction, while highly advanced for their time, now limit its capabilities. The VLA Expansion Project will replace those older technologies with modern technology, allowing the VLA to realize its full potential as a tool for scientific research. "Keeping the VLA at the forefront of technology is an important priority, and we are fortunate that Sen. Pete Domenici (R-NM) has recognized this for many years. We appreciate his longtime support for this valuable scientific facility," Vanden Bout said. "Senator Domenici is one of the VLA's strongest advocates, and as a leader in the U.S. Senate, has continually supported the VLA and its expansion in Congress and the Federal Government," Vanden Bout added. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Flat-plate solar array progress and plans

NASA Technical Reports Server (NTRS)

Callaghan, W. T.; Henry, P. K.

1984-01-01

The Flat-Plate Solar Array Project (FSA), sponsored by the U.S. Department of Energy (DOE) and managed by the Jet Propulsion Laboratory (JPL), has achieved progress in a broad range of technical activities since that reported at the Fourth European Communities Conference. A particularly important analysis has been completed recently which confirms the adoption into practice by the U.S. Photovoltaic (PV Industry, of all the low-cost module technology elements proposed at the 16th Project Integration Meeting for a $2.80/Wp (1980 U.S. Dollars) design approach in the fall of 1980. This work presents along with a projection, using the same techniques, for what is believed to be a very credible ribbon-based module design for less that $0.55/Wp (1980 U.S. Dollars). Other areas to be reported upon include low-cost Si feedstock refinement; ribbon growth; process sequence development for cells; environmental isolation; engineering science investigations; and module testing progress.

In Situ Aerosol Optical Thickness Collected by the SIMBIOS Program (1997-2000): Protocols, and and Data QC and Analysis

NASA Technical Reports Server (NTRS)

Fargion, Giulietta S.; Barnes, Robert; McClain, Charles

2001-01-01

The purpose of this technical report is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project Office activities on in situ aerosol optical thickness (i.e., protocols, and data QC and analysis). This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of validating and combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational project.

Predicting Breed Composition Using Breed Frequencies of 50,000 Markers from the U.S. Meat Animal Research Center 2,000 Bull Project

USDA-ARS?s Scientific Manuscript database

Our objective was to evaluate whether breed composition of crossbred cattle could be predicted using reference breed frequencies of SNP markers on the BovineSNP50 array. Semen DNA samples of over 2,000 bulls from 16 common commercial beef breeds were genotyped using the array and used to estimate cu...

FPGA Based Adaptive Rate and Manifold Pattern Projection for Structured Light 3D Camera System †

PubMed Central

Lee, Sukhan

2018-01-01

The quality of the captured point cloud and the scanning speed of a structured light 3D camera system depend upon their capability of handling the object surface of a large reflectance variation in the trade-off of the required number of patterns to be projected. In this paper, we propose and implement a flexible embedded framework that is capable of triggering the camera single or multiple times for capturing single or multiple projections within a single camera exposure setting. This allows the 3D camera system to synchronize the camera and projector even for miss-matched frame rates such that the system is capable of projecting different types of patterns for different scan speed applications. This makes the system capturing a high quality of 3D point cloud even for the surface of a large reflectance variation while achieving a high scan speed. The proposed framework is implemented on the Field Programmable Gate Array (FPGA), where the camera trigger is adaptively generated in such a way that the position and the number of triggers are automatically determined according to camera exposure settings. In other words, the projection frequency is adaptive to different scanning applications without altering the architecture. In addition, the proposed framework is unique as it does not require any external memory for storage because pattern pixels are generated in real-time, which minimizes the complexity and size of the application-specific integrated circuit (ASIC) design and implementation. PMID:29642506

Proceedings of the 13th Project integration meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1979-01-01

Progress made by the Low Cost Solar Array Project during the period April through August 1979 is presented. Reports are given on project analysis and integration; technology development in silicon material, large area sheet silicon, and encapsulation; production process and equipment development; engineering and operations, and a discussion of the steps taken to integrate these efforts. A report on, and copies of viewgraphs presented at the Project Integration Meeting held August 22-23, 1979 are presented.

Engineering Technical Support Center Annual Report Fiscal Year 2013; Technical Support and Innovative Research for Contaminated Sites

EPA Science Inventory

This report summarizes a variety of significant projects that the ETSC, located in the Land Remediation and Pollution Control Division (LRPCD), National Risk Management Research Laboratory (NRMRL), has supported throughout fiscal year 2013. Projects have addressed an array of env...

"We Could Do Amazing Things"

ERIC Educational Resources Information Center

Summers, Judith

2005-01-01

In this article, the author reports on a Liverpool-based community art project which has used an array of different approaches to unlock the artistic creativity of groups of learners throughout the city. The "Fivearts Cities" project, a partnership between television Channel Five and the Arts Council England, aims to bring new audiences…

DESIGNS FOR ESTIMATING VARIABILITY STRUCTURE AND IMPLICATIONS FOR DETECTING WATERSHED RESTORATION EFFECTIVENESS

EPA Science Inventory

The evaluation of stream restoration projects is moving from a focus on project specific effectiveness to a more holistic evaluation of the array of restoration activities that are or might be imposed to improve conditions across the stream network. Part of evaluating how the con...

Glass for low-cost photovoltaic solar arrays

NASA Technical Reports Server (NTRS)

Bouquet, F. L.

1980-01-01

Various aspects of glass encapsulation that are important for the designer of photovoltaic systems are discussed. Candidate glasses and available information defining the state of the art of glass encapsulation materials and processes for automated, high volume production of terrestrial photovoltaic devices and related applications are presented. The criteria for consideration of the glass encapsulation systems were based on the low-cost solar array project goals for arrays: (1) a low degradation rate, (2) high reliability, (3) an efficiency greater than 10 percent, (4) a total array price less than $500/kW, and (5) a production capacity of 500,000 kW/yr. The glass design areas discussed include the types of glass, sources and costs, physical properties, and glass modifications, such as antireflection coatings.

Magnetic Calorimeter Arrays with High Sensor Inductance and Dense Wiring

NASA Astrophysics Data System (ADS)

Stevenson, T. R.; Balvin, M. A.; Bandler, S. R.; Devasia, A. M.; Nagler, P. C.; Smith, S. J.; Yoon, W.

2018-05-01

We describe prototype arrays of magnetically coupled microcalorimeters fabricated with an approach scalable to very large format arrays. The superconducting interconnections and sensor coils have sufficiently low inductance in the wiring and sufficiently high inductance in the coils in each pixel, to enable arrays containing greater than 4000 sensors and 100,000 X-ray absorbers to be used in future astrophysics missions such as Lynx. We have used projection lithography to create submicron patterns (e.g., 400 nm lines and spaces) in our niobium sensor coils and wiring, integrated with gold-erbium sensor films and gold X-ray absorbers. Our prototype devices will explore the device physics of metallic magnetic calorimeters as feature sizes are reduced to nanoscale.

Modelling spatiotemporal change using multidimensional arrays Meng

NASA Astrophysics Data System (ADS)

Lu, Meng; Appel, Marius; Pebesma, Edzer

2017-04-01

The large variety of remote sensors, model simulations, and in-situ records provide great opportunities to model environmental change. The massive amount of high-dimensional data calls for methods to integrate data from various sources and to analyse spatiotemporal and thematic information jointly. An array is a collection of elements ordered and indexed in arbitrary dimensions, which naturally represent spatiotemporal phenomena that are identified by their geographic locations and recording time. In addition, array regridding (e.g., resampling, down-/up-scaling), dimension reduction, and spatiotemporal statistical algorithms are readily applicable to arrays. However, the role of arrays in big geoscientific data analysis has not been systematically studied: How can arrays discretise continuous spatiotemporal phenomena? How can arrays facilitate the extraction of multidimensional information? How can arrays provide a clean, scalable and reproducible change modelling process that is communicable between mathematicians, computer scientist, Earth system scientist and stakeholders? This study emphasises on detecting spatiotemporal change using satellite image time series. Current change detection methods using satellite image time series commonly analyse data in separate steps: 1) forming a vegetation index, 2) conducting time series analysis on each pixel, and 3) post-processing and mapping time series analysis results, which does not consider spatiotemporal correlations and ignores much of the spectral information. Multidimensional information can be better extracted by jointly considering spatial, spectral, and temporal information. To approach this goal, we use principal component analysis to extract multispectral information and spatial autoregressive models to account for spatial correlation in residual based time series structural change modelling. We also discuss the potential of multivariate non-parametric time series structural change methods, hierarchical modelling, and extreme event detection methods to model spatiotemporal change. We show how array operations can facilitate expressing these methods, and how the open-source array data management and analytics software SciDB and R can be used to scale the process and make it easily reproducible.

Talamanca Transect and Tremor Array: Ongoing Seismological Investigations in Costa Rica

NASA Astrophysics Data System (ADS)

Thorwart, M.; Alvarado, G.; Arroyo, I.; Dinc-Akdogan, N.; Dzierma, Y.; Flueh, E.; Goltz, C.; Gossler, J.; Mora, M.; Rabbel, W.

2005-12-01

Under the roof of the collaborative research centre SFB 574, the Central American subduction zone is being investigated in a seismological research project conducted by Costa Rican and German partners. The general goal of the SFB574 project is to study the origin and influence of volatiles and fluids in subduction zones. The seismological subproject serves to defining the structural and seismo-tectonical frame work of these investigations. In early 2005 two seismic arrays have been installed: (a) A teleseismic transsect across the Talamanca mountain range consisting of 20 broadband sensors with about 10 km station spacing. The primary goal of this array is to image crustal structure, the Moho and the structure of the subducted slab and mantle wedge. Variations in Vp/Vs ratio are expected to provide information on fluids at deep lithospheric levels. (b) An array of six 1Hz-borehole seismometers has been permanently installed in 100 m deep boreholes on Nicoya peninsula. The borehole installation is intended to provide a low-noise environment for recording non-volcanic tremor signals. These non-volcanic tremors are hypothetically understood as indicators of episodic fluid release by dehydratisation processes within the subducting slab. In autumn 2005 the field setup will be complemented by an amphibious network of 30 land and 20 ocean bottom seismometers on- and offshore N Costa Rica and S Nicaragua. The poster presents field layout and first results of the combined SFB574 seismological survey. The SFB574 project is funded by the German science foundation (DFG). Support by the GFZ instrument pool is gratefully acknowledged.

Review of infrared scene projector technology-1993

NASA Astrophysics Data System (ADS)

Driggers, Ronald G.; Barnard, Kenneth J.; Burroughs, E. E.; Deep, Raymond G.; Williams, Owen M.

1994-07-01

The importance of testing IR imagers and missile seekers with realistic IR scenes warrants a review of the current technologies used in dynamic infrared scene projection. These technologies include resistive arrays, deformable mirror arrays, mirror membrane devices, liquid crystal light valves, laser writers, laser diode arrays, and CRTs. Other methods include frustrated total internal reflection, thermoelectric devices, galvanic cells, Bly cells, and vanadium dioxide. A description of each technology is presented along with a discussion of their relative benefits and disadvantages. The current state of each methodology is also summarized. Finally, the methods are compared and contrasted in terms of their performance parameters.

Integrated Solar-Panel Antenna Array for CubeSats

NASA Technical Reports Server (NTRS)

Baktur, Reyhan

2016-01-01

The goal of the Integrated Solar-Panel Antenna Array for CubeSats (ISAAC) project is to design and demonstrate an effective and efficien toptically transparent, high-gain, lightweight, conformal X-band antenna array that is integrated with the solar panels of a CubeSat. The targeted demonstration is for a Near Earth Network (NEN)radio at X-band, but the design can be easilyscaled to other network radios for higher frequencies. ISAAC is a less expensive and more flexible design for communication systemscompared to a deployed dish antenna or the existing integrated solar panel antenna design.

Technology developments toward 30-year-life of photovoltaic modules

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1984-01-01

As part of the United States National Photovoltaics Program, the Jet Propulsion Laboratory's Flat-Plate Solar Array Project (FSA) has maintained a comprehensive reliability and engineering sciences activity addressed toward understanding the reliability attributes of terrestrial flat-plate photovoltaic arrays and to deriving analysis and design tools necessary to achieve module designs with a 30-year useful life. The considerable progress to date stemming from the ongoing reliability research is discussed, and the major areas requiring continued research are highlighted. The result is an overview of the total array reliability problem and of available means of achieving high reliability at minimum cost.

Renewable Energy at NASA's Johnson Space Center

NASA Technical Reports Server (NTRS)

McDowall, Lindsay

2014-01-01

NASA's Johnson Space Center has implemented a great number of renewable energy systems. Renewable energy systems are necessary to research and implement if we humans are expected to continue to grow and thrive on this planet. These systems generate energy using renewable sources - water, wind, sun - things that we will not run out of. Johnson Space Center is helping to pave the way by installing and studying various renewable energy systems. The objective of this report will be to examine the completed renewable energy projects at NASA's Johnson Space Center for a time span of ten years, beginning in 2003 and ending in early 2014. This report will analyze the success of each project based on actual vs. projected savings and actual vs. projected efficiency. Additionally, both positive and negative experiences are documented so that lessons may be learned from past experiences. NASA is incorporating renewable energy wherever it can, including into buildings. According to the 2012 JSC Annual Sustainability Report, there are 321,660 square feet of green building space on JSC's campus. The two projects discussed here are major contributors to that statistic. These buildings were designed to meet various Leadership in Energy and Environmental Design (LEED) Certification criteria. LEED Certified buildings use 30 to 50 percent less energy and water compared to non-LEED buildings. The objectives of this project were to examine data from the renewable energy systems in two of the green buildings onsite - Building 12 and Building 20. In Building 12, data was examined from the solar photovoltaic arrays. In Building 20, data was examined from the solar water heater system. By examining the data from the two buildings, it could be determined if the renewable energy systems are operating efficiently. Objectives In Building 12, the data from the solar photovoltaic arrays shows that the system is continuously collecting energy from the sun, as shown by the graph below. Building 12 has two solar inverters, located on the second floor, that collected the data from the solar photovoltaic arrays. The data displayed here is the total energy produced by the system. These are cumulative amounts, so the last point on the graph shows all of the energy collected from the system since the start of its operation. The data shown here was manually collected from the solar inverters. However, the data is also automatically recorded through EBI. Through analysis of both sets of data it was determined that the EBI data was faulty. For example, from the manually collected data it can be determined that a total of 73 kWh of energy was collected between the dates of 1/16/2014 – 1/22/2014. The EBI data reports that approximately 17800 kWh of energy was collected during the same time frame. Not only does this exceed the time frame examined, but it also exceeds the total energy collected from the start of collection as recorded from the inverters. This leads to the belief that there is a malfunction with the automatic recording of the energy. In Building 20, data was examined from the solar water heater dating back many months and found that the pump for the solar water heater system was not operating properly, as exhibited in the graph shown below. The pump operates on a solar energy system, meaning that it collects energy throughout the day from the sun. Because of this, the system would stop operating shortly after the sun set because of a lack of sunlight. At that point, the graph should show a zero flow rate, but as exhibited in the graph below, that is not the case. It is clearly shown that the pump is continuously operating, even during the night. It was also observed that the majority of the time the pump would not turn on at all, despite good weather conditions. This led to the conclusion that the pump is malfunctioning, and needs to be examined and fixed.

Use of Geodetic Surveys of Leveling Lines and Dry Tilt Arrays to Study Faults and Volcanoes in Undergraduate Field Geophysics Classes

NASA Astrophysics Data System (ADS)

Polet, J.; Alvarez, K.; Elizondo, K.

2017-12-01

In the early 1980's and 1990's numerous leveling lines and dry tilt arrays were installed throughout Central and Southern California by United States Geological Survey scientists and other researchers (e.g. Sylvester, 1985). These lines or triangular arrays of geodetic monuments commonly straddle faults or have been installed close to volcanic areas, where significant motion is expected over relatively short time periods. Over the past year, we have incorporated geodetic surveys of these arrays as part of our field exercises in undergraduate and graduate level classes on topics such as shallow subsurface geophysics and field geophysics. In some cases, the monuments themselves first had to be located based on only limited information, testing students' Brunton use and map reading skills. Monuments were then surveyed using total stations and global navigation satellite system (GNSS) receivers, using a variety of experimental procedures. The surveys were documented with tables, photos, maps and graphs in field reports, as well as in wiki pages created by student groups for a geophysics field class this June. The measurements were processed by the students and compared with similar data from surveys conducted soon after installation of the arrays, to analyze the deformation that occurred over the last few decades. The different geodetic techniques were also compared and an error analysis was conducted. The analysis and processing of these data challenged and enhanced students' quantitative literacy and technology skills. The final geodetic measurements are being incorporated into several senior and MSc thesis projects. Further surveys are planned for additional classes, in topics that could include seismology, geodesy, volcanology and global geophysics. We are also considering additional technologies, such as structure from motion (SfM) photogrammetry.

Phase Velocity and Full-Waveform Analysis of Co-located Distributed Acoustic Sensing (DAS) Channels and Geophone Sensor

NASA Astrophysics Data System (ADS)

Parker, L.; Mellors, R. J.; Thurber, C. H.; Wang, H. F.; Zeng, X.

2015-12-01

A 762-meter Distributed Acoustic Sensing (DAS) array with a channel spacing of one meter was deployed at the Garner Valley Downhole Array in Southern California. The array was approximately rectangular with dimensions of 180 meters by 80 meters. The array also included two subdiagonals within the rectangle along which three-component geophones were co-located. Several active sources were deployed, including a 45-kN, swept-frequency, shear-mass shaker, which produced strong Rayleigh waves across the array. Both DAS and geophone traces were filtered in 2-Hz steps between 4 and 20 Hz to obtain phase velocities as a function of frequency from fitting the moveout of travel times over distances of 35 meters or longer. As an alternative to this traditional means of finding phase velocity, it is theoretically possible to find the Rayleigh-wave phase velocity at each point of co-location as the ratio of DAS and geophone responses, because DAS is sensitive to ground strain and geophones are sensitive to ground velocity, after suitable corrections for instrument response (Mikumo & Aki, 1964). The concept was tested in WPP, a seismic wave propagation program, by first validating and then using a 3D synthetic, full-waveform seismic model to simulate the effect of increased levels of noise and uncertainty as data go from ideal to more realistic. The results obtained from this study provide a better understanding of the DAS response and its potential for being combined with traditional seismometers for obtaining phase velocity at a single location. This analysis is part of the PoroTomo project (Poroelastic Tomography by Adjoint Inverse Modeling of Data from Seismology, Geodesy, and Hydrology, http://geoscience.wisc.edu/feigl/porotomo).

Application of data cubes for improving detection of water cycle extreme events

NASA Astrophysics Data System (ADS)

Teng, W. L.; Albayrak, A.

2015-12-01

As part of an ongoing NASA-funded project to remove a longstanding barrier to accessing NASA data (i.e., accessing archived time-step array data as point-time series), for the hydrology and other point-time series-oriented communities, "data cubes" are created from which time series files (aka "data rods") are generated on-the-fly and made available as Web services from the Goddard Earth Sciences Data and Information Services Center (GES DISC). Data cubes are data as archived rearranged into spatio-temporal matrices, which allow for easy access to the data, both spatially and temporally. A data cube is a specific case of the general optimal strategy of reorganizing data to match the desired means of access. The gain from such reorganization is greater the larger the data set. As a use case for our project, we are leveraging existing software to explore the application of the data cubes concept to machine learning, for the purpose of detecting water cycle extreme (WCE) events, a specific case of anomaly detection, requiring time series data. We investigate the use of the sequential probability ratio test (SPRT) for anomaly detection and support vector machines (SVM) for anomaly classification. We show an example of detection of WCE events, using the Global Land Data Assimilation Systems (GLDAS) data set.

Application of Data Cubes for Improving Detection of Water Cycle Extreme Events

NASA Technical Reports Server (NTRS)

Albayrak, Arif; Teng, William

2015-01-01

As part of an ongoing NASA-funded project to remove a longstanding barrier to accessing NASA data (i.e., accessing archived time-step array data as point-time series), for the hydrology and other point-time series-oriented communities, "data cubes" are created from which time series files (aka "data rods") are generated on-the-fly and made available as Web services from the Goddard Earth Sciences Data and Information Services Center (GES DISC). Data cubes are data as archived rearranged into spatio-temporal matrices, which allow for easy access to the data, both spatially and temporally. A data cube is a specific case of the general optimal strategy of reorganizing data to match the desired means of access. The gain from such reorganization is greater the larger the data set. As a use case of our project, we are leveraging existing software to explore the application of the data cubes concept to machine learning, for the purpose of detecting water cycle extreme events, a specific case of anomaly detection, requiring time series data. We investigate the use of support vector machines (SVM) for anomaly classification. We show an example of detection of water cycle extreme events, using data from the Tropical Rainfall Measuring Mission (TRMM).

High performing actuation system for use with a louver array for satellite thermal control. [design and performance tests on prototype Bourdon spiral configuration

NASA Technical Reports Server (NTRS)

Reusser, P. U.; Coebergh, J. A. F.

1973-01-01

A high performing actuation system has been developed to drive one pair or a set of 9 pairs of louver blades. The system uses a Bourdon spiral as the driving member. The response time of the liquid expansion of the spiral system is in the order of three seconds. Besides performance tests, qualification tests have been carried out on a prototype system, demonstrating that the actuation system withstands normal launching conditions; projected operating life of 7 years with more than 7000 cycles can be expected.

The development and utilization of solar photovoltaic cells: An assessment of the potential for a new energy technology

NASA Technical Reports Server (NTRS)

Cyr, K. J.

1981-01-01

The Government set the goal of accelerating the adaptation of photovoltaics by reducing system costs to a competitive level and overcoming the technical, institutional, legal, environmental, and social barriers impeding the diffusion of photovoltaic technology. The technology of silicon solar arrays was examined and the status of development efforts are reviewed. The political, legal, economic, social, and environmental issues are discussed, and several methods for selecting development projects are described. A number of market forecasting techniques, including time trend, judgemental, and econometric methods, were reviewed, and the results of these models are presented.

Method for Enhancing a Three Dimensional Image from a Plurality of Frames of Flash LIDAR Data

NASA Technical Reports Server (NTRS)

Bulyshev, Alexander (Inventor); Vanek, Michael D. (Inventor); Amzajerdian, Farzin (Inventor)

2013-01-01

A method for enhancing a three dimensional image from frames of flash LIDAR data includes generating a first distance R(sub i) from a first detector i to a first point on a surface S(sub i). After defining a map with a mesh theta having cells k, a first array S(k), a second array M(k), and a third array D(k) are initialized. The first array corresponds to the surface, the second array corresponds to the elevation map, and the third array D(k) receives an output for the DEM. The surface is projected onto the mesh theta, so that a second distance R(sub k) from a second point on the mesh theta to the detector can be found. From this, a height may be calculated, which permits the generation of a digital elevation map. Also, using sequential frames of flash LIDAR data, vehicle control is possible using an offset between successive frames.

Radio Synthesis Imaging - A High Performance Computing and Communications Project

NASA Astrophysics Data System (ADS)

Crutcher, Richard M.

The National Science Foundation has funded a five-year High Performance Computing and Communications project at the National Center for Supercomputing Applications (NCSA) for the direct implementation of several of the computing recommendations of the Astronomy and Astrophysics Survey Committee (the "Bahcall report"). This paper is a summary of the project goals and a progress report. The project will implement a prototype of the next generation of astronomical telescope systems - remotely located telescopes connected by high-speed networks to very high performance, scalable architecture computers and on-line data archives, which are accessed by astronomers over Gbit/sec networks. Specifically, a data link has been installed between the BIMA millimeter-wave synthesis array at Hat Creek, California and NCSA at Urbana, Illinois for real-time transmission of data to NCSA. Data are automatically archived, and may be browsed and retrieved by astronomers using the NCSA Mosaic software. In addition, an on-line digital library of processed images will be established. BIMA data will be processed on a very high performance distributed computing system, with I/O, user interface, and most of the software system running on the NCSA Convex C3880 supercomputer or Silicon Graphics Onyx workstations connected by HiPPI to the high performance, massively parallel Thinking Machines Corporation CM-5. The very computationally intensive algorithms for calibration and imaging of radio synthesis array observations will be optimized for the CM-5 and new algorithms which utilize the massively parallel architecture will be developed. Code running simultaneously on the distributed computers will communicate using the Data Transport Mechanism developed by NCSA. The project will also use the BLANCA Gbit/s testbed network between Urbana and Madison, Wisconsin to connect an Onyx workstation in the University of Wisconsin Astronomy Department to the NCSA CM-5, for development of long-distance distributed computing. Finally, the project is developing 2D and 3D visualization software as part of the international AIPS++ project. This research and development project is being carried out by a team of experts in radio astronomy, algorithm development for massively parallel architectures, high-speed networking, database management, and Thinking Machines Corporation personnel. The development of this complete software, distributed computing, and data archive and library solution to the radio astronomy computing problem will advance our expertise in high performance computing and communications technology and the application of these techniques to astronomical data processing.

K-Band Phased Array Developed for Low- Earth-Orbit Satellite Communications

NASA Technical Reports Server (NTRS)

Anzic, Godfrey

1999-01-01

Future rapid deployment of low- and medium-Earth-orbit satellite constellations that will offer various narrow- to wide-band wireless communications services will require phased-array antennas that feature wide-angle and superagile electronic steering of one or more antenna beams. Antennas, which employ monolithic microwave integrated circuits (MMIC), are perfectly suited for this application. Under a cooperative agreement, an MMIC-based, K-band phased-array antenna is being developed with 50/50 cost sharing by the NASA Lewis Research Center and Raytheon Systems Company. The transmitting array, which will operate at 19 gigahertz (GHz), is a state-of-the-art design that features dual, independent, electronically steerable beam operation ( 42 ), a stand-alone thermal management, and a high-density tile architecture. This array can transmit 622 megabits per second (Mbps) in each beam from Earth orbit to small Earth terminals. The weight of the total array package is expected to be less than 8 lb. The tile integration technology (flip chip MMIC tile) chosen for this project represents a major advancement in phased-array engineering and holds much promise for reducing manufacturing costs.

Data Acquisition Visualization Development for the MAJORANA DEMONSTRATOR

NASA Astrophysics Data System (ADS)

Wendlandt, Laura; Howe, Mark; Wilkerson, John; Majorana Collaboration

2013-10-01

The MAJORANA Project is building an array of germanium detectors with very low backgrounds in order to search for neutrinoless double-beta decay, a rare process that, if detected, would give us information about neutrinos. This decay would prove that neutrinos are their own anti-particles, would show that lepton number is not conserved, and would help determine absolute neutrino mass. An object-oriented, data acquisition software program known as ORCA (Object-oriented Real-time Control and Acquisition) will be used to collect data from the array. This paper describes the implementation of computer visualizations for detector calibrations, as well as tools for more general computer modeling in ORCA. Specifically, it details software that converts a CAD file to OpenGL, which can be used in ORCA. This paper also contains information about using a barium-133 source to take measurements from various locations around the detector, to better understand how data varies with detector crystal orientation. Work made possible by National Science Foundation Award OCI-1155614.

Advanced Catalysts for Fuel Cells

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R.; Whitacre, Jay; Valdez, T. I.

2006-01-01

This viewgraph presentation reviews the development of catalyst for Fuel Cells. The objectives of the project are to reduce the cost of stack components and reduce the amount of precious metal used in fuel cell construction. A rapid combinatorial screening technique based on multi-electrode thin film array has been developed and validated for identifying catalysts for oxygen reduction; focus shifted from methanol oxidation in FY05 to oxygen reduction in FY06. Multi-electrode arrays of thin film catalysts of Pt-Ni and Pt-Ni-Zr have been deposited. Pt-Ni and have been characterized electrochemically and structurally. Pt-Ni-Zr and Pt-Ni films show higher current density and onset potential compared to Pt. Electrocatalytic activity and onset potential are found to be strong function of the lattice constant. Thin film Pt(59)Ni(39)Zr(2) can provide 10 times the current density of thin film Pt. Thin film Pt(59)Ni(39)Zr(2) also shows 65mV higher onset potential than Pt.

Sensitivity of the Cherenkov Telescope Array to the Detection of Intergalactic Magnetic Fields

NASA Astrophysics Data System (ADS)

Meyer, Manuel; Conrad, Jan; Dickinson, Hugh

2016-08-01

Very high energy (VHE; energy E ≳ 100 GeV) γ-rays originating from extragalactic sources undergo pair production with low-energy photons of background radiation fields. These pairs can inverse-Compton-scatter background photons, initiating an electromagnetic cascade. The spatial and temporal structure of this secondary γ-ray signal is altered as the {e}+{e}- pairs are deflected in an intergalactic magnetic field (IGMF). We investigate how VHE observations with the future Cherenkov Telescope Array, with its high angular resolution and broad energy range, can potentially probe the IGMF. We identify promising sources and simulate γ-ray spectra over a wide range of values of the IGMF strength and coherence length using the publicly available ELMAG Monte Carlo code. Combining simulated observations in a joint likelihood approach, we find that current limits on the IGMF can be significantly improved. The projected sensitivity depends strongly on the time a source has been γ-ray active and on the emitted maximum γ-ray energy.

Problems in nonlinear acoustics: Pulsed finite amplitude sound beams, nonlinear acoustic wave propagation in a liquid layer, nonlinear effects in asymmetric cylindrical sound beams, effects of absorption on the interaction of sound beams, and parametric receiving arrays

NASA Astrophysics Data System (ADS)

Hamilton, Mark F.

1990-12-01

This report discusses five projects all of which involve basic theoretical research in nonlinear acoustics: (1) pulsed finite amplitude sound beams are studied with a recently developed time domain computer algorithm that solves the KZK nonlinear parabolic wave equation; (2) nonlinear acoustic wave propagation in a liquid layer is a study of harmonic generation and acoustic soliton information in a liquid between a rigid and a free surface; (3) nonlinear effects in asymmetric cylindrical sound beams is a study of source asymmetries and scattering of sound by sound at high intensity; (4) effects of absorption on the interaction of sound beams is a completed study of the role of absorption in second harmonic generation and scattering of sound by sound; and (5) parametric receiving arrays is a completed study of parametric reception in a reverberant environment.

Light field geometry of a Standard Plenoptic Camera.

PubMed

Hahne, Christopher; Aggoun, Amar; Haxha, Shyqyri; Velisavljevic, Vladan; Fernández, Juan Carlos Jácome

2014-11-03

The Standard Plenoptic Camera (SPC) is an innovation in photography, allowing for acquiring two-dimensional images focused at different depths, from a single exposure. Contrary to conventional cameras, the SPC consists of a micro lens array and a main lens projecting virtual lenses into object space. For the first time, the present research provides an approach to estimate the distance and depth of refocused images extracted from captures obtained by an SPC. Furthermore, estimates for the position and baseline of virtual lenses which correspond to an equivalent camera array are derived. On the basis of paraxial approximation, a ray tracing model employing linear equations has been developed and implemented using Matlab. The optics simulation tool Zemax is utilized for validation purposes. By designing a realistic SPC, experiments demonstrate that a predicted image refocusing distance at 3.5 m deviates by less than 11% from the simulation in Zemax, whereas baseline estimations indicate no significant difference. Applying the proposed methodology will enable an alternative to the traditional depth map acquisition by disparity analysis.

Analysis of mean time to data loss of fault-tolerant disk arrays RAID-6 based on specialized Markov chain

NASA Astrophysics Data System (ADS)

Rahman, P. A.; D'K Novikova Freyre Shavier, G.

2018-03-01

This scientific paper is devoted to the analysis of the mean time to data loss of redundant disk arrays RAID-6 with alternation of data considering different failure rates of disks both in normal state of the disk array and in degraded and rebuild states, and also nonzero time of the disk replacement. The reliability model developed by the authors on the basis of the Markov chain and obtained calculation formula for estimation of the mean time to data loss (MTTDL) of the RAID-6 disk arrays are also presented. At last, the technique of estimation of the initial reliability parameters and examples of calculation of the MTTDL of the RAID-6 disk arrays for the different numbers of disks are also given.

Commercial/industrial photovoltaic module and array requirement study. Low-cost solar array project engineering area

NASA Technical Reports Server (NTRS)

1981-01-01

Design requirements for photovoltaic modules and arrays used in commercial and industrial applications were identified. Building codes and referenced standards were reviewed for their applicability to commercial and industrial photovoltaic array installation. Four general installation types were identified - integral (replaces roofing), direct (mounted on top of roofing), stand-off (mounted away from roofing), and rack (for flat or low slope roofs, or ground mounted). Each of the generic mounting types can be used in vertical wall mounting systems. This implies eight mounting types exist in the commercial/industrial sector. Installation costs were developed for these mounting types as a function of panel/module size. Cost drivers were identified. Studies were performed to identify optimum module shapes and sizes and operating voltage cost drivers. The general conclusion is that there are no perceived major obstacles to the use of photovoltaic modules in commercial/industrial arrays.

Experimental Investigation of the Herschel-Quincke Tube Concept on the Honeywell TFE731-60

NASA Technical Reports Server (NTRS)

Smith, Jerome P.; Burdisso, Ricardo A.; Gerhold, Carl H. (Technical Monitor)

2002-01-01

This report summarizes the key results obtained by the Vibration and Acoustics Laboratories at Virginia Tech over the period from January 1999 to December 2000 on the project 'Investigation of an Adaptive Herschel-Quincke Tube Concept for the Reduction of Tonal and Broadband Noise from Turbofan Engines', funded by NASA Langley Research Center. The Herschel-Quincke (HQ) tube concept is a developing technique that consists of circumferential arrays of tubes around the duct. A fixed array of tubes is installed on the inlet duct of the Honeywell TFE731-60 engine. Two array designs are incorporated into the inlet treatment, each designed for a different circumferential mode order which is expected to be cut on in the duct. Far field and in-duct noise measurement data are presented which demonstrate the effectiveness of the HQ concept for array 1, array 2, and both operating simultaneously.

The GenoChip: a new tool for genetic anthropology.

PubMed

Elhaik, Eran; Greenspan, Elliott; Staats, Sean; Krahn, Thomas; Tyler-Smith, Chris; Xue, Yali; Tofanelli, Sergio; Francalacci, Paolo; Cucca, Francesco; Pagani, Luca; Jin, Li; Li, Hui; Schurr, Theodore G; Greenspan, Bennett; Spencer Wells, R

2013-01-01

The Genographic Project is an international effort aimed at charting human migratory history. The project is nonprofit and nonmedical, and, through its Legacy Fund, supports locally led efforts to preserve indigenous and traditional cultures. Although the first phase of the project was focused on uniparentally inherited markers on the Y-chromosome and mitochondrial DNA (mtDNA), the current phase focuses on markers from across the entire genome to obtain a more complete understanding of human genetic variation. Although many commercial arrays exist for genome-wide single-nucleotide polymorphism (SNP) genotyping, they were designed for medical genetic studies and contain medically related markers that are inappropriate for global population genetic studies. GenoChip, the Genographic Project's new genotyping array, was designed to resolve these issues and enable higher resolution research into outstanding questions in genetic anthropology. The GenoChip includes ancestry informative markers obtained for over 450 human populations, an ancient human (Saqqaq), and two archaic hominins (Neanderthal and Denisovan) and was designed to identify all known Y-chromosome and mtDNA haplogroups. The chip was carefully vetted to avoid inclusion of medically relevant markers. To demonstrate its capabilities, we compared the FST distributions of GenoChip SNPs to those of two commercial arrays. Although all arrays yielded similarly shaped (inverse J) FST distributions, the GenoChip autosomal and X-chromosomal distributions had the highest mean FST, attesting to its ability to discern subpopulations. The chip performances are illustrated in a principal component analysis for 14 worldwide populations. In summary, the GenoChip is a dedicated genotyping platform for genetic anthropology. With an unprecedented number of approximately 12,000 Y-chromosomal and approximately 3,300 mtDNA SNPs and over 130,000 autosomal and X-chromosomal SNPs without any known health, medical, or phenotypic relevance, the GenoChip is a useful tool for genetic anthropology and population genetics.

Structure of the Suasselkä postglacial fault in northern Finland obtained by analysis of local events and ambient seismic noise

NASA Astrophysics Data System (ADS)

Afonin, Nikita; Kozlovskaya, Elena; Kukkonen, Ilmo; Dafne/Finland Working Group

2017-04-01

Understanding the inner structure of seismogenic faults and their ability to reactivate is particularly important in investigating the continental intraplate seismicity regime. In our study we address this problem using analysis of local seismic events and ambient seismic noise recorded by the temporary DAFNE array in the northern Fennoscandian Shield. The main purpose of the DAFNE/FINLAND passive seismic array experiment was to characterize the present-day seismicity of the Suasselkä postglacial fault (SPGF), which was proposed as one potential target for the DAFNE (Drilling Active Faults in Northern Europe) project. The DAFNE/FINLAND array comprised an area of about 20 to 100 km and consisted of eight short-period and four broadband three-component autonomous seismic stations installed in the close vicinity of the fault area. The array recorded continuous seismic data during September 2011-May 2013. Recordings of the array have being analysed in order to identify and locate natural earthquakes from the fault area and to discriminate them from the blasts in the Kittilä gold mine. As a result, we found a number of natural seismic events originating from the fault area, which proves that the fault is still seismically active. In order to study the inner structure of the SPGF we use cross-correlation of ambient seismic noise recorded by the array. Analysis of azimuthal distribution of noise sources demonstrated that during the time interval under consideration the distribution of noise sources is close to the uniform one. The continuous data were processed in several steps including single-station data analysis, instrument response removal and time-domain stacking. The data were used to estimate empirical Green's functions between pairs of stations in the frequency band of 0.1-1 Hz and to calculate corresponding surface wave dispersion curves. The S-wave velocity models were obtained as a result of dispersion curve inversion. The results suggest that the area of the SPGF corresponds to a narrow region of low S-wave velocities surrounded by rocks with high S-wave velocities. We interpret this low-velocity region as a non-healed mechanically weak fault damage zone (FDZ) formed due to the last major earthquake that occurred after the last glaciation.

S-Wave Velocity Structure of the Taiwan Chelungpu Fault Drilling Project (TCDP) Site Using Microtremor Array Measurements

NASA Astrophysics Data System (ADS)

Wu, Cheng-Feng; Huang, Huey-Chu

2015-10-01

The Taiwan Chelungpu Fault Drilling Project (TCDP) drilled a 2-km-deep hole 2.4 km east of the surface rupture of the 1999 Chi-Chi earthquake ( M w 7.6), near the town of Dakeng. Geophysical well logs at the TCDP site were run over depths ranging from 500 to 1,900 m to obtain the physical properties of the fault zones and adjacent damage zones. These data provide good reference material for examining the validity of velocity structures using microtremor array measurement; therefore, we conduct array measurements for a total of four arrays at two sites near the TCDP drilling sites. The phase velocities at frequencies of 0.2-5 Hz are calculated using the frequency-wavenumber ( f- k) spectrum method. Then the S-wave velocity structures are estimated by employing surface wave inversion techniques. The S-wave velocity from the differential inversion technique gradually increases from 1.52 to 2.22 km/s at depths between 585 and 1,710 m. This result is similar to those from the velocity logs, which range from 1.4 km/s at a depth of 597 m to 2.98 km/s at a depth of 1,705 m. The stochastic inversion results are similar to those from the seismic reflection methods and the lithostratigraphy of TCDP-A borehole, comparatively. These results show that microtremor array measurement provides a good tool for estimating deep S-wave velocity structure.