Electromagnetic pulse excitation of finite- and infinitely-long lossy conductors over a lossy ground plane

DOE PAGES

Campione, Salvatore; Warne, Larry K.; Basilio, Lorena I.; ...

2017-01-13

This study details a model for the response of a finite- or an infinite-length wire interacting with a conducting ground to an electromagnetic pulse excitation. We develop a frequency–domain method based on transmission line theory that we name ATLOG – Analytic Transmission Line Over Ground. This method is developed as an alternative to full-wave methods, as it delivers a fast and reliable solution. It allows for the treatment of finite or infinite lossy, coated wires, and lossy grounds. The cases of wire above ground, as well as resting on the ground and buried beneath the ground are treated. The reportedmore » method is general and the time response of the induced current is obtained using an inverse Fourier transform of the current in the frequency domain. The focus is on the characteristics and propagation of the transmission line mode. Comparisons with full-wave simulations strengthen the validity of the proposed method.« less

Electromagnetic pulse excitation of finite- and infinitely-long lossy conductors over a lossy ground plane

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

Campione, Salvatore; Warne, Larry K.; Basilio, Lorena I.

This study details a model for the response of a finite- or an infinite-length wire interacting with a conducting ground to an electromagnetic pulse excitation. We develop a frequency–domain method based on transmission line theory that we name ATLOG – Analytic Transmission Line Over Ground. This method is developed as an alternative to full-wave methods, as it delivers a fast and reliable solution. It allows for the treatment of finite or infinite lossy, coated wires, and lossy grounds. The cases of wire above ground, as well as resting on the ground and buried beneath the ground are treated. The reportedmore » method is general and the time response of the induced current is obtained using an inverse Fourier transform of the current in the frequency domain. The focus is on the characteristics and propagation of the transmission line mode. Comparisons with full-wave simulations strengthen the validity of the proposed method.« less

IMF By effects on ground magnetometer response to increased solar wind dynamic pressure derived from global MHD simulations

NASA Astrophysics Data System (ADS)

Ozturk, Dogacan Su; Zou, Shasha; Slavin, James A.

2017-05-01

During sudden solar wind dynamic pressure enhancements, the magnetosphere undergoes rapid compression resulting in a reconfiguration of the global current systems, most notably the field-aligned currents (FACs). Ground-based magnetometers are traditionally used to study such compression events. However, factors affecting the polarity and magnitude of the ground-based magnetic perturbations are still not well understood. In particular, interplanetary magnetic field (IMF) By is known to create significant asymmetries in the FAC patterns. We use the University of Michigan Block Adaptive Tree Roe Upwind Scheme (BATS'R'US) magnetohydrodynamic code to investigate the effects of IMF By on the global variations of ground magnetic perturbations during solar wind dynamic pressure enhancements. Using virtual magnetometers in three idealized simulations with varying IMF By, we find asymmetries in the peak amplitude and magnetic local time of the ground magnetic perturbations during the preliminary impulse (PI) and the main impulse (MI) phases. These asymmetries are especially evident at high-latitude ground magnetometer responses where the peak amplitudes differ by 50 nT at different locations. We show that the FACs related with the PI are due to magnetopause deformation, and the FACs related with the MI are generated by vortical flows within the magnetosphere, consistent with other simulation results. The perturbation FACs due to pressure enhancements and their magnetospheric sources do not differ much under different IMF By polarities. However, the conductance profile affected by the superposition of the preexisting FACs and the perturbation FACs including their closure currents is responsible for the magnitude and location asymmetries in the ground magnetic perturbations.

Which future for electromagnetic Astronomy: Ground Based vs Space Borne Large Astrophysical Facilities

NASA Astrophysics Data System (ADS)

Ubertini, Pietro

2015-08-01

The combined use of large ground based facilities and large space observatories is playing a key role in the advance of astrophysics by providing access to the entire electromagnetic spectrum, allowing high sensitivity observations from the lower radio wavelength to the higher energy gamma rays.It is nowadays clear that a forward steps in the understanding of the Universe evolution and large scale structure formation is essential and only possible with the combined use of multiwavelength imaging and spectral high resolution instruments.The increasing size, complexity and cost of large ground and space observatories places a growing emphasis on international collaboration. If the present set of astronomical facilities is impressive and complete, with nicely complementary space and ground based telescopes, the scenario becomes worrisome and critical in the next two decades. In fact, only a few ‘Large’ main space missions are planned and there is a need to ensure proper ground facility coverage: the synergy Ground-Space is not escapable in the timeframe 2020-2030.The scope of this talk is to review the current astronomical instrumentation panorama also in view of the recent major national agencies and international bodies programmatic decisions.This Division B meeting give us a unique opportunity to review the current situation and discuss the future perspectives taking advantage of the large audience ensured by the IAU GA.

Flight- and Ground-Based Materials Science Programs at NASA

NASA Technical Reports Server (NTRS)

Gillies, Donald C.

1999-01-01

The Microgravity Research Division of NASA funds research programs in all branches of materials science including ceramics and glasses. A NASA Research Announcement (NRA)is currently planned with proposals due in March 1999. Proposals are accepted for both flight- definition and ground- based research projects with a main criterion being a strong justification for microgravity. A review of the program in its entirety will be given, with special emphasis on microgravity related ceramics research. The topics of current interest in the NRA will be discussed in terms of International Space Station research and NASA's Human Exploration and Development of Space (HEDS) initiative.

Nuclear Attack on U.S. Space-Based Assets: Current Strategy, Policy, Reality, and Implications for the Future.

DTIC Science & Technology

1998-06-05

other.46 This can be useful when certain links 70 have been negated through the destruction of a ground station or actual jamming or interference...system is to attack the enemy’s ground station.59 The link segment can be jammed or spoofed60. However, the DoD has nothing in its inventory currently...currently conducted primarily by jamming assets that prevent the enemy use of his systems. These systems are classified and can only be discussed in

US Air Force Air Base Ground Defense Doctrine. Are The Issues Which Arose Concerning Air Base Ground Defense During the Vietnam Conflict Recognized in Current US Air Force Doctrine

DTIC Science & Technology

1984-05-01

Conflict; US efforts to overcome these difficulties_ statistics concerning hostile attacks against air bases and the results thereof (8]; and, a...buses. During the period from � through 1973 the threat to ,air bacses iontinued, as reflected in the air base attack statistics provided ,at...advantage of aI r base vulnerabi lities to gather detailed intelligenrci concerning the air bases. C1 48 -STANDOFF ATTACKS- Based upon the statistics in

A summary of existing and planned experiment hardware for low-gravity fluids research

NASA Technical Reports Server (NTRS)

Hill, Myron E.; Omalley, Terence F.

1991-01-01

An overview is presented of (1) existing ground-based, low gravity research facilities, with examples of hardware capabilities, and (2) existing and planned space-based research facilities, with examples of current and past flight hardware. Low-gravity, ground-based facilities, such as drop towers and aircraft, provide the experimenter with quick turnaround time, easy access to equipment, gravity levels ranging from 10(exp -2) to 10(exp -6) G, and low-gravity durations ranging from 2 to 30 sec. Currently, the only operational space-based facility is the Space Shuttle. The Shuttle's payload bay and middeck facilities are described. Existing and planned low-gravity fluids research facilities are also described with examples of experiments and hardware capabilities.

A study on seismic behavior of pile foundations of bridge abutment on liquefiable ground through shaking table tests

NASA Astrophysics Data System (ADS)

Nakata, Mitsuhiko; Tanimoto, Shunsuke; Ishida, Shuichi; Ohsumi, Michio; Hoshikuma, Jun-ichi

2017-10-01

There is risk of bridge foundations to be damaged by liquefaction-induced lateral spreading of ground. Once bridge foundations have been damaged, it takes a lot of time for restoration. Therefore, it is important to assess the seismic behavior of the foundations on liquefiable ground appropriately. In this study, shaking table tests of models on a scale of 1/10 were conducted at the large scale shaking table in Public Works Research Institute, Japan, to investigate the seismic behavior of pile-supported bridge abutment on liquefiable ground. The shaking table tests were conducted for three types of model. Two are models of existing bridge which was built without design for liquefaction and the other is a model of bridge which was designed based on the current Japanese design specifications for highway bridges. As a result, the bending strains of piles of the abutment which were designed based on the current design specifications were less than those of the existing bridge.

46 CFR 111.05-27 - Grounded neutral alternating current systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the ground connection, is able to withstand the maximum available fault current without damage, and... 46 Shipping 4 2011-10-01 2011-10-01 false Grounded neutral alternating current systems. 111.05-27... Grounded neutral alternating current systems. Grounded neutral and high-impedance grounded neutral...

46 CFR 111.05-27 - Grounded neutral alternating current systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the ground connection, is able to withstand the maximum available fault current without damage, and... 46 Shipping 4 2010-10-01 2010-10-01 false Grounded neutral alternating current systems. 111.05-27... Grounded neutral alternating current systems. Grounded neutral and high-impedance grounded neutral...

A study of electron density profiles in relation to ionization sources and ground-based radio wave absorption measurements, part 1

NASA Technical Reports Server (NTRS)

Gnanalingam, S.; Kane, J. A.

1973-01-01

An extensive set of ground-based measurements of the diurnal variation of medium frequency radio wave adsorption and virtual height is analyzed in terms of current understanding of the D- and lower E-region ion production and loss process. When this is done a gross discrepancy arises, the source of which is not known.

Orbital debris measurements

NASA Astrophysics Data System (ADS)

Kessler, D. J.

What is currently known about the orbital debris flux is from a combination of ground based and in-space measurements. These measurements have revealed an increasing population with decreasing size. A summary of measurements is presented for the following sources: the North American Aerospace Defense Command Catalog, the Perimeter Acquisition and Attack Characterization System Radar, ground based optical telescopes, the Explorer 46 Meteoroid Bumper Experiment, spacecraft windows, and Solar Max surfaces.

Orbital debris measurements

NASA Technical Reports Server (NTRS)

Kessler, D. J.

1986-01-01

What is currently known about the orbital debris flux is from a combination of ground based and in-space measurements. These measurements have revealed an increasing population with decreasing size. A summary of measurements is presented for the following sources: the North American Aerospace Defense Command Catalog, the Perimeter Acquisition and Attack Characterization System Radar, ground based optical telescopes, the Explorer 46 Meteoroid Bumper Experiment, spacecraft windows, and Solar Max surfaces.

The Great Observatories Origins Deep Survey (GOODS): Overview and Status

NASA Astrophysics Data System (ADS)

Hook, R. N.; GOODS Team

2002-12-01

GOODS is a very large project to gather deep imaging data and spectroscopic followup of two fields, the Hubble Deep Field North (HDF-N) and the Chandra Deep Field South (CDF-S), with both space and ground-based instruments to create an extensive multiwavelength public data set for community research on the distant Universe. GOODS includes a SIRTF Legacy Program (PI: Mark Dickinson) and a Hubble Treasury Program of ACS imaging (PI: Mauro Giavalisco). The ACS imaging was also optimized for the detection of high-z supernovae which are being followed up by a further target of opportunity Hubble GO Program (PI: Adam Riess). The bulk of the CDF-S ground-based data presently available comes from an ESO Large Programme (PI: Catherine Cesarsky) which includes both deep imaging and multi-object followup spectroscopy. This is currently complemented in the South by additional CTIO imaging. Currently available HDF-N ground-based data forming part of GOODS includes NOAO imaging. Although the SIRTF part of the survey will not begin until later in the year the ACS imaging is well advanced and there is also a huge body of complementary ground-based imaging and some follow-up spectroscopy which is already publicly available. We summarize the current status of GOODS and give an overview of the data products currently available and present the timescales for the future. Many early science results from the survey are presented in other GOODS papers at this meeting. Support for the HST GOODS program presented here and in companion abstracts was provided by NASA thorugh grant number GO-9425 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

Solar Adaptive Optics.

PubMed

Rimmele, Thomas R; Marino, Jose

Adaptive optics (AO) has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO) and Ground-Layer AO (GLAO) will be given. Supplementary material is available for this article at 10.12942/lrsp-2011-2.

Viscous grounding lines

NASA Astrophysics Data System (ADS)

Worster, Grae; Huppert, Herbert; Robison, Rosalyn; Nandkishore, Rahul; Rajah, Luke

2008-11-01

We have used simple laboratory experiments with viscous fluids to explore the dynamics of grounding lines between Antarctic marine ice sheets and the freely floating ice shelves into which they develop. Ice sheets are shear-dominated gravity currents, while ice shelves are extensional gravity currents with zero shear to leading order. Though ice sheets have non-Newtonian rheology, fundamental aspects of their flow can be explored using Newtonian fluid mechanics. We have derived a mathematical model of this flow that incorporates a new dynamic boundary condition for the position of the grounding line, where the gravity current loses contact with the solid base. Good agreement between our theoretical predictions and our experimental measurements, made using gravity currents of syrup flowing down a rigid slope into a deep, dense salt solution, gives confidence in the fundamental assumptions of our model, which can be incorporated into shallow-ice models to make important predictions regarding the dynamical stability of marine ice sheets.

The atmospheric electric global circuit. [thunderstorm activity

NASA Technical Reports Server (NTRS)

Kasemir, H. W.

1979-01-01

The hypothesis that world thunderstorm activity represents the generator for the atmospheric electric current flow in the earth atmosphere between ground and the ionosphere is based on a close correlation between the magnitude and the diurnal variation of the supply current (thunderstorm generator current) and the load current (fair weather air-earth current density integrated over the earth surface). The advantages of using lightning survey satellites to furnish a base for accepting or rejecting the thunderstorm generator hypothesis are discussed.

Direct DC 10 V comparison between two programmable Josephson voltage standards made of niobium nitride (NbN)-based and niobium (Nb)-based Josephson junctions

NASA Astrophysics Data System (ADS)

Solve, S.; Chayramy, R.; Maruyama, M.; Urano, C.; Kaneko, N.-H.; Rüfenacht, A.

2018-04-01

BIPM’s new transportable programmable Josephson voltage standard (PJVS) has been used for an on-site comparison at the National Metrology Institute of Japan (NMIJ) and the National Institute of Advanced Industrial Science and Technology (AIST) (NMIJ/AIST, hereafter called just NMIJ unless otherwise noted). This is the first time that an array of niobium-based Josephson junctions with amorphous niobium silicon Nb x Si1-x barriers, developed by the National Institute of Standards and Technology4 (NIST), has been directly compared to an array of niobium nitride (NbN)-based junctions (developed by the NMIJ in collaboration with the Nanoelectronics Research Institute (NeRI), AIST). Nominally identical voltages produced by both systems agreed within 5 parts in 1012 (0.05 nV at 10 V) with a combined relative uncertainty of 7.9  ×  10-11 (0.79 nV). The low side of the NMIJ apparatus is, by design, referred to the ground potential. An analysis of the systematic errors due to the leakage current to ground was conducted for this ground configuration. The influence of a multi-stage low-pass filter installed at the output measurement leads of the NMIJ primary standard was also investigated. The number of capacitances in parallel in the filter and their insulation resistance have a direct impact on the amplitude of the systematic voltage error introduced by the leakage current, even if the current does not necessarily return to ground. The filtering of the output of the PJVS voltage leads has the positive consequence of protecting the array from external sources of noise. Current noise, when coupled to the array, reduces the width or current range of the quantized voltage steps. The voltage error induced by the leakage current in the filter is an order of magnitude larger than the voltage error in the absence of all filtering, even though the current range of steps is significantly decreased without filtering.

Validation and understanding of Moderate Resolution Imaging Spectroradiometer aerosol products (C5) using ground-based measurements from the handheld Sun photometer network in China

Treesearch

Zhanqing Li; Feng Niu; Kwon-Ho Lee; Jinyuan Xin; Wei Min Hao; Bryce L. Nordgren; Yuesi Wang; Pucai Wang

2007-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) currently provides the most extensive aerosol retrievals on a global basis, but validation is limited to a small number of ground stations. This study presents a comprehensive evaluation of Collection 4 and 5 MODIS aerosol products using ground measurements from the Chinese Sun Hazemeter Network (CSHNET). The...

Calculations of lightning return stroke electric and magnetic fields above ground

NASA Technical Reports Server (NTRS)

Master, M. J.; Uman, M. A.; Ling, Y. T.; Standler, R. B.

1981-01-01

Lin et al., (1980) presented a lightning return stroke model with which return stroke electric and magnetic fields measured at ground level could be reproduced. This model and a modified version of it, in which the initial current peak decays with height above ground, are used to compute waveforms for altitudes from 0-10 km and at ranges of 20 m to 10 km. Both the original and modified models gave accurate predictions of measured ground-based fields. The use of the calculated fields in calibrating airborne field measurements from simultaneous ground and airborne data is discussed.

T cell regulation in microgravity - The current knowledge from in vitro experiments conducted in space, parabolic flights and ground-based facilities

NASA Astrophysics Data System (ADS)

Hauschild, Swantje; Tauber, Svantje; Lauber, Beatrice; Thiel, Cora S.; Layer, Liliana E.; Ullrich, Oliver

2014-11-01

Dating back to the Apollo and Skylab missions, it has been reported that astronauts suffered from bacterial and viral infections during space flight or after returning to Earth. Blood analyses revealed strongly reduced capability of human lymphocytes to become active upon mitogenic stimulation. Since then, a large number of in vitro studies on human immune cells have been conducted in space, in parabolic flights, and in ground-based facilities. It became obvious that microgravity affects cell morphology and important cellular functions. Observed changes include cell proliferation, the cytoskeleton, signal transduction and gene expression. This review gives an overview of the current knowledge of T cell regulation under altered gravity conditions obtained by in vitro studies with special emphasis on the cell culture conditions used. We propose that future in vitro experiments should follow rigorous standardized cell culture conditions, which allows better comparison of the results obtained in different flight- and ground-based experiment platforms.

Ukrainian Program for Material Science in Microgravity

NASA Astrophysics Data System (ADS)

Fedorov, Oleg

Ukrainian Program for Material Sciences in Microgravity O.P. Fedorov, Space Research Insti-tute of NASU -NSAU, Kyiv, The aim of the report is to present previous and current approach of Ukrainian research society to the prospect of material sciences in microgravity. This approach is based on analysis of Ukrainian program of research in microgravity, preparation of Russian -Ukrainian experiments on Russian segment of ISS and development of new Ukrainian strategy of space activity for the years 2010-2030. Two parts of issues are discussed: (i) the evolution of our views on the priorities in microgravity research (ii) current experiments under preparation and important ground-based results. item1 The concept of "space industrialization" and relevant efforts in Soviet and post -Soviet Ukrainian research institutions are reviewed. The main topics are: melt supercooling, crystal growing, testing of materials, electric welding and study of near-Earth environment. The anticipated and current results are compared. item 2. The main experiments in the framework of Ukrainian-Russian Research Program for Russian Segment of ISS are reviewed. Flight installations under development and ground-based results of the experiments on directional solidification, heat pipes, tribological testing, biocorrosion study is presented. Ground-based experiments and theoretical study of directional solidification of transparent alloys are reviewed as well as preparation of MORPHOS installation for study of succinonitrile -acetone in microgravity.

Data fusion and photometric restoration

NASA Astrophysics Data System (ADS)

Pirzkal, Norbert; Hook, Richard N.

2001-11-01

The current generation of 8-10m optical ground-based telescopes have a symbiotic relationship with space telescopes. For direct imaging in the optical the former can collect photons relatively cheaply but the latter can still achieve, even in the era of adaptive optics, significantly higher spatial resolution, point-spread function stability and astrometric fidelity over fields of a few arcminutes. The large archives of HST imaging already in place, when combined with the ease of access to ground-based data afforded by the virtual observatory currently under development, will make space-ground data fusion a powerful tool for the future. We describe a photometric image restoration method that we have developed which allows the efficient and accurate use of high-resolution space imaging of crowded fields to extract high quality photometry from very crowded ground-based images. We illustrate the method using HST and ESO VLT/FORS imaging of a globular cluster and demonstrate quantitatively the photometric measurements quality that can achieved using the data fusion approach instead of just using data from just one telescope. This method can handle most of the common difficulties encountered when attempting this problem such as determining the geometric mapping to the requisite precision, deriving the PSF and the background.

Computer Program for Thin Wire Antenna over a Perfectly Conducting Ground Plane. [using Galerkins method and sinusoidal bases

NASA Technical Reports Server (NTRS)

Richmond, J. H.

1974-01-01

A computer program is presented for a thin-wire antenna over a perfect ground plane. The analysis is performed in the frequency domain, and the exterior medium is free space. The antenna may have finite conductivity and lumped loads. The output data includes the current distribution, impedance, radiation efficiency, and gain. The program uses sinusoidal bases and Galerkin's method.

Assimilation of Spatially Sparse In Situ Soil Moisture Networks into a Continuous Model Domain

NASA Astrophysics Data System (ADS)

Gruber, A.; Crow, W. T.; Dorigo, W. A.

2018-02-01

Growth in the availability of near-real-time soil moisture observations from ground-based networks has spurred interest in the assimilation of these observations into land surface models via a two-dimensional data assimilation system. However, the design of such systems is currently hampered by our ignorance concerning the spatial structure of error afflicting ground and model-based soil moisture estimates. Here we apply newly developed triple collocation techniques to provide the spatial error information required to fully parameterize a two-dimensional (2-D) data assimilation system designed to assimilate spatially sparse observations acquired from existing ground-based soil moisture networks into a spatially continuous Antecedent Precipitation Index (API) model for operational agricultural drought monitoring. Over the contiguous United States (CONUS), the posterior uncertainty of surface soil moisture estimates associated with this 2-D system is compared to that obtained from the 1-D assimilation of remote sensing retrievals to assess the value of ground-based observations to constrain a surface soil moisture analysis. Results demonstrate that a fourfold increase in existing CONUS ground station density is needed for ground network observations to provide a level of skill comparable to that provided by existing satellite-based surface soil moisture retrievals.

Prediction of ground effects on aircraft noise

NASA Technical Reports Server (NTRS)

Pao, S. P.; Wenzel, A. R.; Oncley, P. B.

1978-01-01

A unified method is recommended for predicting ground effects on noise. This method may be used in flyover noise predictions and in correcting static test-stand data to free-field conditions. The recommendation is based on a review of recent progress in the theory of ground effects and of the experimental evidence which supports this theory. It is shown that a surface wave must be included sometimes in the prediction method. Prediction equations are collected conveniently in a single section of the paper. Methods of measuring ground impedance and the resulting ground-impedance data are also reviewed because the recommended method is based on a locally reactive impedance boundary model. Current practice of estimating ground effects are reviewed and consideration is given to practical problems in applying the recommended method. These problems include finite frequency-band filters, finite source dimension, wind and temperature gradients, and signal incoherence.

A biophysical model of Lake Erie walleye (Sander vitreus) explains interannual variations in recruitment

USGS Publications Warehouse

Zhao, Yingming; Jones, Michael L.; Shuter, Brian J.; Roseman, Edward F.

2009-01-01

We used a three-dimensional coupled hydrodynamic-ecological model to investigate how lake currents can affect walleye (Sander vitreus) recruitment in western Lake Erie. Four years were selected based on a fall recruitment index: two high recruitment years (i.e., 1996 and 1999) and two low recruitment years (i.e., 1995 and 1998). During the low recruitment years, the model predicted that (i) walleye spawning grounds experienced destructive bottom currents capable of dislodging eggs from suitable habitats (reefs) to unsuitable habitats (i.e., muddy bottom), and (ii) the majority of newly hatched larvae were transported away from the known suitable nursery grounds at the start of their first feeding. Conversely, during two high recruitment years, predicted bottom currents at the spawning grounds were relatively weak, and the predicted movement of newly hatched larvae was toward suitable nursery grounds. Thus, low disturbance-based egg mortality and a temporal and spatial match between walleye first feeding larvae and their food resources were predicted for the two high recruitment years, and high egg mortality plus a mismatch of larvae with their food resources was predicted for the two low recruitment years. In general, mild westerly or southwesterly winds during the spawning-nursery period should favour walleye recruitment in the lake.

Analysis of ground-water data for selected wells near Holloman Air Force Base, New Mexico, 1950-95

USGS Publications Warehouse

Huff, G.F.

1996-01-01

Ground-water-level, ground-water-withdrawal, and ground- water-quality data were evaluated for trends. Holloman Air Force Base is located in the west-central part of Otero County, New Mexico. Ground-water-data analyses include assembly and inspection of U.S. Geological Survey and Holloman Air Force Base data, including ground-water-level data for public-supply and observation wells and withdrawal and water-quality data for public-supply wells in the area. Well Douglas 4 shows a statistically significant decreasing trend in water levels for 1972-86 and a statistically significant increasing trend in water levels for 1986-90. Water levels in wells San Andres 5 and San Andres 6 show statistically significant decreasing trends for 1972-93 and 1981-89, respectively. A mixture of statistically significant increasing trends, statistically significant decreasing trends, and lack of statistically significant trends over periods ranging from the early 1970's to the early 1990's are indicated for the Boles wells and wells near the Boles wells. Well Boles 5 shows a statistically significant increasing trend in water levels for 1981-90. Well Boles 5 and well 17S.09E.25.343 show no statistically significant trends in water levels for 1990-93 and 1988-93, respectively. For 1986-93, well Frenchy 1 shows a statistically significant decreasing trend in water levels. Ground-water withdrawal from the San Andres and Douglas wells regularly exceeded estimated ground-water recharge from San Andres Canyon for 1963-87. For 1951-57 and 1960-86, ground-water withdrawal from the Boles wells regularly exceeded total estimated ground-water recharge from Mule, Arrow, and Lead Canyons. Ground-water withdrawal from the San Andres and Douglas wells and from the Boles wells nearly equaled estimated ground- water recharge for 1989-93 and 1986-93, respectively. For 1987- 93, ground-water withdrawal from the Escondido well regularly exceeded estimated ground-water recharge from Escondido Canyon, and ground-water withdrawal from the Frenchy wells regularly exceeded total estimated ground-water recharge from Dog and Deadman Canyons. Water-quality samples were collected from selected Douglas, San Andres, and Boles public-supply wells from December 1994 to February 1995. Concentrations of dissolved nitrate show the most consistent increases between current and historical data. Current concentrations of dissolved nitrate are greater than historical concentrations in 7 of 10 wells.

Conjugate Magnetic Observations in the Polar Environments by PRIMO and AUTUMNX

NASA Astrophysics Data System (ADS)

Chi, P. J.; Russell, C. T.; Strangeway, R. J.; Raymond, C. A.; Connors, M. G.; Wilson, T. J.; Boteler, D. H.; Rowe, K.; Schofield, I.

2014-12-01

While magnetically conjugate observations by ground-based magnetometers are available at both high and low magnetic latitudes, few have been established at auroral latitudes to monitor the hemispheric asymmetry of auroral electric currents and its impact to geospace dynamics. Due to the limitations of global land areas, the only regions where conjugate ground-based magnetic observations can cover the full range of auroral latitudes are between Quebec, Canada and West Antarctica. Funded by the Canadian Space Agency, the AUTUMNX project is currently emplacing 10 ground-based magnetometers in Quebec, Canada, and will provide the magnetic field observations in the Northern Hemisphere. The proposed U.S. Polar Region Interhemispheric Magnetic Observatories (PRIMO) project plans to establish six new ground-based magnetometers in West Antarctica at L-values between 3.9 and 10.1. The instrument is based on the new low-power fluxgate magnetometer system recently developed at UCLA for operation in the polar environments. The PRIMO magnetometers will operate on the power and communications platform well proven by the POLENET project, and the six PRIMO systems will co-locate with existing ANET stations in the region for synergy in logistic support. Focusing on the American longitudinal sector and leveraging infrastructure through international collaborations, PRIMO and AUTUMNX can monitor the intensity and location of auroral electrojets in both hemispheres simultaneously, enabling the first systematic interhemispheric magnetic observations at auroral latitudes.

Countering Air and Missile Threats

DTIC Science & Technology

2007-02-05

ground-based radars will not be obstructed by the curvature of the earth and airborne radars can discriminate them from ground clutter. As a result...Iraqi fighters. Around Baghdad, “The whole ground was red with Triple-A fire as far as you could see,” recalled one pilot. The four F-15s were...Element NORAD) is the supported commander in accordance with the NORAD Agreement, NORAD Terms of Reference, etc. CDRNORAD is currently allocated

Electrochemical stabilization of clayey ground

USGS Publications Warehouse

Rzhanitzin, B.A.; Sokoloff, V.P.

1947-01-01

Recently developed new methods of stabilization of weak grounds (e.g. the silicate treatment) are based on injection of chemical solutions into the ground. Such methods are applicable accordingly only to the kinds of ground that have the coefficient of filtration higher than 2 meters per 24 hours and permit penetration of the chemical solutions under pressure. This limit, however, as it is shown by our experience in construction, excludes a numerous and an important class of grounds, stabilization of which is indispensable in many instances. For example, digging of trenches and pits in clayey, silty, or sandy ground shows that all these types act like typical "floaters" (sluds? -S) in the presence of the ground water pressure. There were several instances in the canalization of the city of Moskow where the laying of trenches below the ground water level has led to extreme difficulties with clayey and silty ground. Similar examples could be cited in mining, engineering hydrology, and railroad construction. For these reasons, the development of methods of stabilizing such difficult types of ground has become an urgent problem of our day. In 1936, the author began his investigations, at the ground Stabilization Laboratory of VODGEO Institute, with direct electrical current as the means of stabilization of grounds. Experiments had shown that a large number of clayey types, following passage of direct electrical current, undergoes a transformation of its physico-chemical properties. It was established that the (apparent -S) density of the ground is substantially increased in consequence of the application of direct electrical current. The ground loses also its capacity to swell and to soften in water. Later, after a more detailed study of the physico-chemical mechanism of the electrical stabilization, it became possible to develop the method so as to make it applicable to sandy and silty as well as to clayey ground. By this time (1941, S.), the method has already been tested in the field, was found satisfactory, and is being introduced into construction practice.

Laser Interferometry for Gravitational Wave Observation: LISA and LISA Pathfinder

NASA Technical Reports Server (NTRS)

Guzman, Felipe

2010-01-01

The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1mHz-100mHz. This observation band is inaccessible to ground-based detectors due to the large ground motions of the Earth. Gravitational wave sources for LISA include galactic binaries, mergers of supermasive black-hole binaries, extreme-mass-ratio inspirals, and possibly from as yet unimagined sources. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset oF 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such us spacecraft control with micro-newton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of flight hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. An introduction to laser interferometric gravitational wave detection, ground-based observatories, and a detailed description of the two missions together with an overview of current investigations conducted by the community will bc discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented

Common Ground of Two Paradigms: Incorporating Critical Theory into Current Art Therapy Practices

ERIC Educational Resources Information Center

Nolan, Emily

2013-01-01

Clinical art therapy and studio-based community art therapy represent two major paradigms in art therapy practice. This viewpoint explores how critical theory can be incorporated into both paradigms and result in common ground between them. Critical theory encompasses an understanding of oppression in psychological, social, and cultural contexts…

Atmospheric Visibility Monitoring for planetary optical communications

NASA Technical Reports Server (NTRS)

Cowles, Kelly

1991-01-01

The Atmospheric Visibility Monitoring project endeavors to improve current atmospheric models and generate visibility statistics relevant to prospective earth-satellite optical communications systems. Three autonomous observatories are being used to measure atmospheric conditions on the basis of observed starlight; these data will yield clear-sky and transmission statistics for three sites with high clear-sky probabilities. Ground-based data will be compared with satellite imagery to determine the correlation between satellite data and ground-based observations.

New Ground Based facilities in QSO research; The GTC

NASA Astrophysics Data System (ADS)

Rodriguez Espinosa, J. M.

New ground based observing opportunities are becoming, or about to become, available to astronomers for QSO research. These, combined with state of the art focal plane instruments, provide unprecedented sensitivity for detecting faint surface brightness features. During the talk I will take the liberty of talking about one of these new large telescope facilities currently being built in Spain, and will discuss some of the advantages for QSO research offered by these new facilities.

Constraining Modified Theories of Gravity with Gravitational-Wave Stochastic Backgrounds

NASA Astrophysics Data System (ADS)

Maselli, Andrea; Marassi, Stefania; Ferrari, Valeria; Kokkotas, Kostas; Schneider, Raffaella

2016-08-01

The direct discovery of gravitational waves has finally opened a new observational window on our Universe, suggesting that the population of coalescing binary black holes is larger than previously expected. These sources produce an unresolved background of gravitational waves, potentially observable by ground-based interferometers. In this Letter we investigate how modified theories of gravity, modeled using the parametrized post-Einsteinian formalism, affect the expected signal, and analyze the detectability of the resulting stochastic background by current and future ground-based interferometers. We find the constraints that Advanced LIGO would be able to set on modified theories, showing that they may significantly improve the current bounds obtained from astrophysical observations of binary pulsars.

Device, system and method for a sensing electrical circuit

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2009-01-01

The invention relates to a driven ground electrical circuit. A driven ground is a current-measuring ground termination to an electrical circuit with the current measured as a vector with amplification. The driven ground module may include an electric potential source V.sub.S driving an electric current through an impedance (load Z) to a driven ground. Voltage from the source V.sub.S excites the minus terminal of an operational amplifier inside the driven ground which, in turn, may react by generating an equal and opposite voltage to drive the net potential to approximately zero (effectively ground). A driven ground may also be a means of passing information via the current passing through one grounded circuit to another electronic circuit as input. It may ground one circuit, amplify the information carried in its current and pass this information on as input to the next circuit.

Ground-Based Lidar for Atmospheric Boundary Layer Ozone Measurements

NASA Technical Reports Server (NTRS)

Kuang, Shi; Newchurch, Michael J.; Burris, John; Liu, Xiong

2013-01-01

Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than 10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

Why NASA and the Space Electronics Community Cares About Cyclotrons

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.

2017-01-01

NASA and the space community are faced with the harsh reality of operating electronic systems in the space radiation environment. Systems need to work reliably (as expected for as long as expected) and be available during critical operations such as docking or firing a thruster. This talk will provide a snapshot of the import of ground-based research on the radiation performance of electronics. Discussion topics include: 1) The space radiation environment hazard, 2) Radiation effects on electronics, 3) Simulation of effects with cyclotrons (and other sources), 4) Risk prediction for space missions, and, 5) Real-life examples of both ground-based testing and space-based anomalies and electronics performance. The talk will conclude with a discussion of the current state of radiation facilities in North America for ground-based electronics testing.

Minimizing eddy currents induced in the ground plane of a large phased-array ultrasound applicator for echo-planar imaging-based MR thermometry.

PubMed

Lechner-Greite, Silke M; Hehn, Nicolas; Werner, Beat; Zadicario, Eyal; Tarasek, Matthew; Yeo, Desmond

2016-01-01

The study aims to investigate different ground plane segmentation designs of an ultrasound transducer to reduce gradient field induced eddy currents and the associated geometric distortion and temperature map errors in echo-planar imaging (EPI)-based MR thermometry in transcranial magnetic resonance (MR)-guided focused ultrasound (tcMRgFUS). Six different ground plane segmentations were considered and the efficacy of each in suppressing eddy currents was investigated in silico and in operando. For the latter case, the segmented ground planes were implemented in a transducer mockup model for validation. Robust spoiled gradient (SPGR) echo sequences and multi-shot EPI sequences were acquired. For each sequence and pattern, geometric distortions were quantified in the magnitude images and expressed in millimeters. Phase images were used for extracting the temperature maps on the basis of the temperature-dependent proton resonance frequency shift phenomenon. The means, standard deviations, and signal-to-noise ratios (SNRs) were extracted and contrasted with the geometric distortions of all patterns. The geometric distortion analysis and temperature map evaluations showed that more than one pattern could be considered the best-performing transducer. In the sagittal plane, the star (d) (3.46 ± 2.33 mm) and star-ring patterns (f) (2.72 ± 2.8 mm) showed smaller geometric distortions than the currently available seven-segment sheet (c) (5.54 ± 4.21 mm) and were both comparable to the reference scenario (a) (2.77 ± 2.24 mm). Contrasting these results with the temperature maps revealed that (d) performs as well as (a) in SPGR and EPI. We demonstrated that segmenting the transducer ground plane into a star pattern reduces eddy currents to a level wherein multi-plane EPI for accurate MR thermometry in tcMRgFUS is feasible.

30 CFR 75.703-2 - Approved grounding mediums.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Approved grounding mediums. 75.703-2 Section 75... mediums. For purposes of grounding offtrack direct-current machines, the following grounding mediums are... alternating current grounding medium where such machines are fed by an ungrounded direct-current power system...

30 CFR 75.703-2 - Approved grounding mediums.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Approved grounding mediums. 75.703-2 Section 75... mediums. For purposes of grounding offtrack direct-current machines, the following grounding mediums are... alternating current grounding medium where such machines are fed by an ungrounded direct-current power system...

30 CFR 75.703-2 - Approved grounding mediums.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved grounding mediums. 75.703-2 Section 75... mediums. For purposes of grounding offtrack direct-current machines, the following grounding mediums are... alternating current grounding medium where such machines are fed by an ungrounded direct-current power system...

30 CFR 75.703-2 - Approved grounding mediums.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Approved grounding mediums. 75.703-2 Section 75... mediums. For purposes of grounding offtrack direct-current machines, the following grounding mediums are... alternating current grounding medium where such machines are fed by an ungrounded direct-current power system...

30 CFR 75.703-2 - Approved grounding mediums.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Approved grounding mediums. 75.703-2 Section 75... mediums. For purposes of grounding offtrack direct-current machines, the following grounding mediums are... alternating current grounding medium where such machines are fed by an ungrounded direct-current power system...

Investigating dynamical complexity in the time series of the upgraded ENIGMA magnetometer array using various entropy measures

NASA Astrophysics Data System (ADS)

Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Melis, Nikolaos; Giannakis, Omiros; Kontoes, Charalampos

2016-04-01

The HellENIc GeoMagnetic Array (ENIGMA) is a network of 3 ground-based magnetometer stations in the areas of Trikala, Attiki and Lakonia in Greece that provides measurements for the study of geomagnetic pulsations, resulting from the solar wind - magnetosphere coupling. ENIGMA magnetometer array enables effective remote sensing of geospace dynamics and the study of space weather effects on the ground (i.e., Geomagnetically Induced Currents - GIC). ENIGMA contributes data to SuperMAG, a worldwide collaboration of organizations and national agencies that currently operate more than 300 ground-based magnetometers. ENIGMA is currently extended and upgraded receiving financial support through the national funding KRIPIS project and European Commission's BEYOND project. In particular, the REGPOT project BEYOND is an FP7 project that aims to maintain and expand the existing state-of-the-art interdisciplinary research potential, by Building a Centre of Excellence for Earth Observation based monitoring of Natural Disasters in south-eastern Europe, with a prospect to increase its access range to the wider Mediterranean region through the integrated cooperation with twining organizations. This study explores the applicability and effectiveness of a variety of computable entropy measures to the ENIGMA time series in order to investigate dynamical complexity between pre-storm activity and magnetic storms.

Measurement of surface charges on the dielectric film based on field mills under the HVDC corona wire

NASA Astrophysics Data System (ADS)

Donglai, WANG; Tiebing, LU; Yuan, WANG; Bo, CHEN; Xuebao, LI

2018-05-01

The ion flow field on the ground is one of the significant parameters used to evaluate the electromagnetic environment of high voltage direct current (HVDC) power lines. HVDC lines may cross the greenhouses due to the restricted transmission corridors. Under the condition of ion flow field, the dielectric films on the greenhouses will be charged, and the electric fields in the greenhouses may exceed the limit value. Field mills are widely used to measure the ground-level direct current electric fields under the HVDC power lines. In this paper, the charge inversion method is applied to calculate the surface charges on the dielectric film according to the measured ground-level electric fields. The advantages of hiding the field mill probes in the ground are studied. The charge inversion algorithm is optimized in order to decrease the impact of measurement errors. Based on the experimental results, the surface charge distribution on a piece of quadrate dielectric film under a HVDC corona wire is studied. The enhanced effect of dielectric film on ground-level electric field is obviously weakened with the increase of film height. Compared with the total electric field strengths, the normal components of film-free electric fields at the corresponding film-placed positions have a higher effect on surface charge accumulation.

Current Pedagogical Challenges in Iranian EFL Teachers' Views: A Qualitative Study

ERIC Educational Resources Information Center

Noughabi, Mostafa Azari

2017-01-01

Searching for the real voices in regard to pedagogical challenges Iranian EFL teachers may struggle against seems to be an unexplored issue, which is the purpose of this qualitative grounded study. To achieve generalizable findings, based on the tenets of grounded theory, data were collected using an open-ended questionnaire with 187 Iranian EFL…

Applicability of interferometric SAR technology to ground movement and pipeline monitoring

NASA Astrophysics Data System (ADS)

Grivas, Dimitri A.; Bhagvati, Chakravarthy; Schultz, B. C.; Trigg, Alan; Rizkalla, Moness

1998-03-01

This paper summarizes the findings of a cooperative effort between NOVA Gas Transmission Ltd. (NGTL), the Italian Natural Gas Transmission Company (SNAM), and Arista International, Inc., to determine whether current remote sensing technologies can be utilized to monitor small-scale ground movements over vast geographical areas. This topic is of interest due to the potential for small ground movements to cause strain accumulation in buried pipeline facilities. Ground movements are difficult to monitor continuously, but their cumulative effect over time can have a significant impact on the safety of buried pipelines. Interferometric synthetic aperture radar (InSAR or SARI) is identified as the most promising technique of those considered. InSAR analysis involves combining multiple images from consecutive passes of a radar imaging platform. The resulting composite image can detect changes as small as 2.5 to 5.0 centimeters (based on current analysis methods and radar satellite data of 5 centimeter wavelength). Research currently in progress shows potential for measuring ground movements as small as a few millimeters. Data needed for InSAR analysis is currently commercially available from four satellites, and additional satellites are planned for launch in the near future. A major conclusion of the present study is that InSAR technology is potentially useful for pipeline integrity monitoring. A pilot project is planned to test operational issues.

Field-aligned electric currents and their measurement by the incoherent backscatter technique

NASA Technical Reports Server (NTRS)

Bauer, P.; Cole, K. D.; Lejeume, G.

1975-01-01

Field aligned electric currents flow in the magnetosphere in many situations of fundamental geophysical interest. It is shown here that the incoherent backscatter technique can be used to measure these currents when the plasma line can be observed. The technique provides a ground based means of measuring these currents which complements the rocket and satellite ones.

Calculation of conductivities and currents in the ionosphere

NASA Technical Reports Server (NTRS)

Kirchhoff, V. W. J. H.; Carpenter, L. A.

1975-01-01

Formulas and procedures to calculate ionospheric conductivities are summarized. Ionospheric currents are calculated using a semidiurnal E-region neutral wind model and electric fields from measurements at Millstone Hill. The results agree well with ground based magnetogram records for magnetic quiet days.

Time-averaged current analysis of a thunderstorm using ground-based measurements

NASA Astrophysics Data System (ADS)

Driscoll, Kevin T.; Blakeslee, Richard J.; Koshak, William J.

1994-05-01

The amount of upward current provided to the ionosphere by a thunderstorm that appeared over the Kennedy Space Center (KSC) on July 11, 1978, is reexamined using an analytic equation that describes a bipolar thunderstorm's current contribution to the global circuit in terms of its generator current, lightning currents, the altitudes of its charge centers, and the conductivity profile of the atmosphere. Ground-based measurements, which were obtained from a network of electric field mills positioned at various distances from the thunderstorm, were used to characterize the electrical activity inside the thundercloud. The location of the lightning discharges, the type of lightning, and the amount of charge neutralized during this thunderstorm were computed through a least squares inversion of the measured changes in the electric fields following each lightning discharge. These measurements provided the information necessary to implement the analytic equation, and consequently, a time-averaged estimate of this thunderstorm's current contribution to the global circuit was calculated. From these results the amount of conduction current supplied to the ionosphere by this small thunderstorm was computed to be less than 25% of the time-averaged generator current that flowed between the two vertically displaced charge centers.

Progress Towards the Remote Sensing of Aircraft Icing Hazards

NASA Technical Reports Server (NTRS)

Reehorst, Andrew; Brinker, David; Politovich, Marcia; Serke, David; Ryerson, Charles; Pazmany, Andrew; Solheim, Fredrick

2009-01-01

NASA has teamed with the FAA, DoD, industry, and academia for research into the remote detection and measurement of atmospheric conditions leading to aircraft icing hazards. The ultimate goal of this effort is to provide pilots, controllers, and dispatchers sufficient information to allow aircraft to avoid or minimize their exposure to the hazards of in-flight icing. Since the hazard of in-flight icing is the outcome of aircraft flight through clouds containing supercooled liquid water and strongly influenced by the aircraft s speed and configuration and by the length of exposure, the hazard cannot be directly detected, but must be inferred based upon the measurement of conducive atmospheric conditions. Therefore, icing hazard detection is accomplished through the detection and measurement of liquid water in regions of measured sub-freezing air temperatures. The icing environment is currently remotely measured from the ground with a system fusing radar, lidar, and multifrequency microwave radiometer sensors. Based upon expected ice accretion severity for the measured environment, a resultant aircraft hazard is then calculated. Because of the power, size, weight, and view angle constraints of airborne platforms, the current ground-based solution is not applicable for flight. Two current airborne concepts are based upon the use of either multifrequency radiometers or multifrequency radar. Both ground-based and airborne solutions are required for the future since groundbased systems can provide hazard detection for all aircraft in airport terminal regions while airborne systems will be needed to provide equipped aircraft with flight path coverage between terminal regions.

A new approach to correct for absorbing aerosols in OMI UV

NASA Astrophysics Data System (ADS)

Arola, A.; Kazadzis, S.; Lindfors, A.; Krotkov, N.; Kujanpää, J.; Tamminen, J.; Bais, A.; di Sarra, A.; Villaplana, J. M.; Brogniez, C.; Siani, A. M.; Janouch, M.; Weihs, P.; Webb, A.; Koskela, T.; Kouremeti, N.; Meloni, D.; Buchard, V.; Auriol, F.; Ialongo, I.; Staneck, M.; Simic, S.; Smedley, A.; Kinne, S.

2009-11-01

Several validation studies of surface UV irradiance based on the Ozone Monitoring Instrument (OMI) satellite data have shown a high correlation with ground-based measurements but a positive bias in many locations. The main part of the bias can be attributed to the boundary layer aerosol absorption that is not accounted for in the current satellite UV algorithms. To correct for this shortfall, a post-correction procedure was applied, based on global climatological fields of aerosol absorption optical depth. These fields were obtained by using global aerosol optical depth and aerosol single scattering albedo data assembled by combining global aerosol model data and ground-based aerosol measurements from AERONET. The resulting improvements in the satellite-based surface UV irradiance were evaluated by comparing satellite and ground-based spectral irradiances at various European UV monitoring sites. The results generally showed a significantly reduced bias by 5-20%, a lower variability, and an unchanged, high correlation coefficient.

30 CFR 75.703 - Grounding offtrack direct-current machines and the enclosures of related detached components.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding offtrack direct-current machines and...-UNDERGROUND COAL MINES Grounding § 75.703 Grounding offtrack direct-current machines and the enclosures of related detached components. [Statutory Provisions] The frames of all offtrack direct-current machines and...

30 CFR 75.703 - Grounding offtrack direct-current machines and the enclosures of related detached components.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Grounding offtrack direct-current machines and...-UNDERGROUND COAL MINES Grounding § 75.703 Grounding offtrack direct-current machines and the enclosures of related detached components. [Statutory Provisions] The frames of all offtrack direct-current machines and...

Silicon carbide optics for space and ground based astronomical telescopes

NASA Astrophysics Data System (ADS)

Robichaud, Joseph; Sampath, Deepak; Wainer, Chris; Schwartz, Jay; Peton, Craig; Mix, Steve; Heller, Court

2012-09-01

Silicon Carbide (SiC) optical materials are being applied widely for both space based and ground based optical telescopes. The material provides a superior weight to stiffness ratio, which is an important metric for the design and fabrication of lightweight space telescopes. The material also has superior thermal properties with a low coefficient of thermal expansion, and a high thermal conductivity. The thermal properties advantages are important for both space based and ground based systems, which typically need to operate under stressing thermal conditions. The paper will review L-3 Integrated Optical Systems - SSG’s (L-3 SSG) work in developing SiC optics and SiC optical systems for astronomical observing systems. L-3 SSG has been fielding SiC optical components and systems for over 25 years. Space systems described will emphasize the recently launched Long Range Reconnaissance Imager (LORRI) developed for JHU-APL and NASA-GSFC. Review of ground based applications of SiC will include supporting L-3 IOS-Brashear’s current contract to provide the 0.65 meter diameter, aspheric SiC secondary mirror for the Advanced Technology Solar Telescope (ATST).

Microgravity metal processing: from undercooled liquids to bulk metallic glasses

PubMed Central

Hofmann, Douglas C; Roberts, Scott N

2015-01-01

Bulk metallic glasses (BMGs) are a novel class of metal alloys that are poised for widespread commercialization. Over 30 years of NASA and ESA (as well as other space agency) funding for both ground-based and microgravity experiments has resulted in fundamental science data that have enabled commercial production. This review focuses on the history of microgravity BMG research, which includes experiments on the space shuttle, the ISS, ground-based experiments, commercial fabrication and currently funded efforts. PMID:28725709

Final Environmental Assessment Addressing Construction, Operation, and Maintenance of a Hot Cargo Pad at Kirtland Air Force Base, New Mexico

DTIC Science & Technology

2011-01-01

ground surface of the pad. The surface sludge at WP-26 is currently being removed, which would alleviate any potential adverse effects on the...removing and disposing of the top 5 inches of the ground surface , which is potentially contaminated sewage sludge, within WP-26 in a manner consistent...Construction, Operation, and Maintenance of a Hot Cargo Pad at Kirtland Air Force Base, New Mexico, to identifY and evaluate potential environmental effects

An Overview of the Current Understanding of Gamma-Ray Bursts in the Fermi Era

NASA Technical Reports Server (NTRS)

Bhat, P. N.; Guiriec, Sylvain

2011-01-01

Gamma-ray bursts are the most luminous explosions in the Universe, and their origin as well as mechanism are the focus of intense research and debate. More than three decades since their serendipitous discovery, followed by several breakthroughs from space-borne and ground-based observations, they remain one of the most interesting astrophysical phenomena yet to be completely understood. Since the launch of Fermi with its unprecedented energy band width spanning seven decades, the study of gamma-ray burst research has entered a new phase. Here we review the current theoretical understanding and observational highlights of gamma-ray burst astronomy and point out some of the potential promises of multi-wavelength observations in view of the upcoming ground based observational facilities .

Nowcasting Ground Magnetic Perturbations with the Space Weather Modeling Framework

NASA Astrophysics Data System (ADS)

Welling, D. T.; Toth, G.; Singer, H. J.; Millward, G. H.; Gombosi, T. I.

2015-12-01

Predicting ground-based magnetic perturbations is a critical step towards specifying and predicting geomagnetically induced currents (GICs) in high voltage transmission lines. Currently, the Space Weather Modeling Framework (SWMF), a flexible modeling framework for simulating the multi-scale space environment, is being transitioned from research to operational use (R2O) by NOAA's Space Weather Prediction Center. Upon completion of this transition, the SWMF will provide localized B/t predictions using real-time solar wind observations from L1 and the F10.7 proxy for EUV as model input. This presentation describes the operational SWMF setup and summarizes the changes made to the code to enable R2O progress. The framework's algorithm for calculating ground-based magnetometer observations will be reviewed. Metrics from data-model comparisons will be reviewed to illustrate predictive capabilities. Early data products, such as regional-K index and grids of virtual magnetometer stations, will be presented. Finally, early successes will be shared, including the code's ability to reproduce the recent March 2015 St. Patrick's Day Storm.

Versatile tunable current-mode universal biquadratic filter using MO-DVCCs and MOSFET-based electronic resistors.

PubMed

Chen, Hua-Pin

2014-01-01

This paper presents a versatile tunable current-mode universal biquadratic filter with four-input and three-output employing only two multioutput differential voltage current conveyors (MO-DVCCs), two grounded capacitors, and a well-known method for replacement of three grounded resistors by MOSFET-based electronic resistors. The proposed configuration exhibits high-output impedance which is important for easy cascading in the current-mode operations. The proposed circuit can be used as either a two-input three-output circuit or a three-input single-output circuit. In the operation of two-input three-output circuit, the bandpass, highpass, and bandreject filtering responses can be realized simultaneously while the allpass filtering response can be easily obtained by connecting appropriated output current directly without using additional stages. In the operation of three-input single-output circuit, all five generic filtering functions can be easily realized by selecting different three-input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency, and no inverting-type input current signals are imposed. All the passive and active sensitivities are low. Postlayout simulations were carried out to verify the functionality of the design.

Versatile Tunable Current-Mode Universal Biquadratic Filter Using MO-DVCCs and MOSFET-Based Electronic Resistors

PubMed Central

2014-01-01

This paper presents a versatile tunable current-mode universal biquadratic filter with four-input and three-output employing only two multioutput differential voltage current conveyors (MO-DVCCs), two grounded capacitors, and a well-known method for replacement of three grounded resistors by MOSFET-based electronic resistors. The proposed configuration exhibits high-output impedance which is important for easy cascading in the current-mode operations. The proposed circuit can be used as either a two-input three-output circuit or a three-input single-output circuit. In the operation of two-input three-output circuit, the bandpass, highpass, and bandreject filtering responses can be realized simultaneously while the allpass filtering response can be easily obtained by connecting appropriated output current directly without using additional stages. In the operation of three-input single-output circuit, all five generic filtering functions can be easily realized by selecting different three-input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency, and no inverting-type input current signals are imposed. All the passive and active sensitivities are low. Postlayout simulations were carried out to verify the functionality of the design. PMID:24982963

Aerosol single scattering albedo estimated across China from a combination of ground and satellite measurements

Treesearch

Kwon Ho Lee; Zhanqing Li; Man Sing Wong; Jinyuan Xin; Wang Yuesi; Wei Min Hao; Fengsheng Zhao

2007-01-01

Single scattering albedo (SSA) governs the strength of aerosols in absorbing solar radiation, but few methods are available to directly measure this important quantity. There currently exist many ground-based measurements of spectral transmittance from which aerosol optical thickness (AOT) are retrieved under clear sky conditions. Reflected radiances at the top of the...

Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

NASA Astrophysics Data System (ADS)

Actis, M.; Agnetta, G.; Aharonian, F.; Akhperjanian, A.; Aleksić, J.; Aliu, E.; Allan, D.; Allekotte, I.; Antico, F.; Antonelli, L. A.; Antoranz, P.; Aravantinos, A.; Arlen, T.; Arnaldi, H.; Artmann, S.; Asano, K.; Asorey, H.; Bähr, J.; Bais, A.; Baixeras, C.; Bajtlik, S.; Balis, D.; Bamba, A.; Barbier, C.; Barceló, M.; Barnacka, A.; Barnstedt, J.; Barres de Almeida, U.; Barrio, J. A.; Basso, S.; Bastieri, D.; Bauer, C.; Becerra, J.; Becherini, Y.; Bechtol, K.; Becker, J.; Beckmann, V.; Bednarek, W.; Behera, B.; Beilicke, M.; Belluso, M.; Benallou, M.; Benbow, W.; Berdugo, J.; Berger, K.; Bernardino, T.; Bernlöhr, K.; Biland, A.; Billotta, S.; Bird, T.; Birsin, E.; Bissaldi, E.; Blake, S.; Blanch, O.; Bobkov, A. A.; Bogacz, L.; Bogdan, M.; Boisson, C.; Boix, J.; Bolmont, J.; Bonanno, G.; Bonardi, A.; Bonev, T.; Borkowski, J.; Botner, O.; Bottani, A.; Bourgeat, M.; Boutonnet, C.; Bouvier, A.; Brau-Nogué, S.; Braun, I.; Bretz, T.; Briggs, M. S.; Brun, P.; Brunetti, L.; Buckley, J. H.; Bugaev, V.; Bühler, R.; Bulik, T.; Busetto, G.; Buson, S.; Byrum, K.; Cailles, M.; Cameron, R.; Canestrari, R.; Cantu, S.; Carmona, E.; Carosi, A.; Carr, J.; Carton, P. H.; Casiraghi, M.; Castarede, H.; Catalano, O.; Cavazzani, S.; Cazaux, S.; Cerruti, B.; Cerruti, M.; Chadwick, P. M.; Chiang, J.; Chikawa, M.; Cieślar, M.; Ciesielska, M.; Cillis, A.; Clerc, C.; Colin, P.; Colomé, J.; Compin, M.; Conconi, P.; Connaughton, V.; Conrad, J.; Contreras, J. L.; Coppi, P.; Corlier, M.; Corona, P.; Corpace, O.; Corti, D.; Cortina, J.; Costantini, H.; Cotter, G.; Courty, B.; Couturier, S.; Covino, S.; Croston, J.; Cusumano, G.; Daniel, M. K.; Dazzi, F.; de Angelis, A.; de Cea Del Pozo, E.; de Gouveia Dal Pino, E. M.; de Jager, O.; de La Calle Pérez, I.; de La Vega, G.; de Lotto, B.; de Naurois, M.; de Oña Wilhelmi, E.; de Souza, V.; Decerprit, B.; Deil, C.; Delagnes, E.; Deleglise, G.; Delgado, C.; Dettlaff, T.; di Paolo, A.; di Pierro, F.; Díaz, C.; Dick, J.; Dickinson, H.; Digel, S. W.; Dimitrov, D.; Disset, G.; Djannati-Ataï, A.; Doert, M.; Domainko, W.; Dorner, D.; Doro, M.; Dournaux, J.-L.; Dravins, D.; Drury, L.; Dubois, F.; Dubois, R.; Dubus, G.; Dufour, C.; Durand, D.; Dyks, J.; Dyrda, M.; Edy, E.; Egberts, K.; Eleftheriadis, C.; Elles, S.; Emmanoulopoulos, D.; Enomoto, R.; Ernenwein, J.-P.; Errando, M.; Etchegoyen, A.; Falcone, A. D.; Farakos, K.; Farnier, C.; Federici, S.; Feinstein, F.; Ferenc, D.; Fillin-Martino, E.; Fink, D.; Finley, C.; Finley, J. P.; Firpo, R.; Florin, D.; Föhr, C.; Fokitis, E.; Font, Ll.; Fontaine, G.; Fontana, A.; Förster, A.; Fortson, L.; Fouque, N.; Fransson, C.; Fraser, G. W.; Fresnillo, L.; Fruck, C.; Fujita, Y.; Fukazawa, Y.; Funk, S.; Gäbele, W.; Gabici, S.; Gadola, A.; Galante, N.; Gallant, Y.; García, B.; García López, R. J.; Garrido, D.; Garrido, L.; Gascón, D.; Gasq, C.; Gaug, M.; Gaweda, J.; Geffroy, N.; Ghag, C.; Ghedina, A.; Ghigo, M.; Gianakaki, E.; Giarrusso, S.; Giavitto, G.; Giebels, B.; Giro, E.; Giubilato, P.; Glanzman, T.; Glicenstein, J.-F.; Gochna, M.; Golev, V.; Gómez Berisso, M.; González, A.; González, F.; Grañena, F.; Graciani, R.; Granot, J.; Gredig, R.; Green, A.; Greenshaw, T.; Grimm, O.; Grube, J.; Grudzińska, M.; Grygorczuk, J.; Guarino, V.; Guglielmi, L.; Guilloux, F.; Gunji, S.; Gyuk, G.; Hadasch, D.; Haefner, D.; Hagiwara, R.; Hahn, J.; Hallgren, A.; Hara, S.; Hardcastle, M. J.; Hassan, T.; Haubold, T.; Hauser, M.; Hayashida, M.; Heller, R.; Henri, G.; Hermann, G.; Herrero, A.; Hinton, J. A.; Hoffmann, D.; Hofmann, W.; Hofverberg, P.; Horns, D.; Hrupec, D.; Huan, H.; Huber, B.; Huet, J.-M.; Hughes, G.; Hultquist, K.; Humensky, T. B.; Huppert, J.-F.; Ibarra, A.; Illa, J. M.; Ingjald, J.; Inoue, Y.; Inoue, S.; Ioka, K.; Jablonski, C.; Jacholkowska, A.; Janiak, M.; Jean, P.; Jensen, H.; Jogler, T.; Jung, I.; Kaaret, P.; Kabuki, S.; Kakuwa, J.; Kalkuhl, C.; Kankanyan, R.; Kapala, M.; Karastergiou, A.; Karczewski, M.; Karkar, S.; Karlsson, N.; Kasperek, J.; Katagiri, H.; Katarzyński, K.; Kawanaka, N.; Kȩdziora, B.; Kendziorra, E.; Khélifi, B.; Kieda, D.; Kifune, T.; Kihm, T.; Klepser, S.; Kluźniak, W.; Knapp, J.; Knappy, A. R.; Kneiske, T.; Knödlseder, J.; Köck, F.; Kodani, K.; Kohri, K.; Kokkotas, K.; Komin, N.; Konopelko, A.; Kosack, K.; Kossakowski, R.; Kostka, P.; Kotuła, J.; Kowal, G.; Kozioł, J.; Krähenbühl, T.; Krause, J.; Krawczynski, H.; Krennrich, F.; Kretzschmann, A.; Kubo, H.; Kudryavtsev, V. A.; Kushida, J.; La Barbera, N.; La Parola, V.; La Rosa, G.; López, A.; Lamanna, G.; Laporte, P.; Lavalley, C.; Le Flour, T.; Le Padellec, A.; Lenain, J.-P.; Lessio, L.; Lieunard, B.; Lindfors, E.; Liolios, A.; Lohse, T.; Lombardi, S.; Lopatin, A.; Lorenz, E.; Lubiński, P.; Luz, O.; Lyard, E.; Maccarone, M. C.; Maccarone, T.; Maier, G.; Majumdar, P.; Maltezos, S.; Małkiewicz, P.; Mañá, C.; Manalaysay, A.; Maneva, G.; Mangano, A.; Manigot, P.; Marín, J.; Mariotti, M.; Markoff, S.; Martínez, G.; Martínez, M.; Mastichiadis, A.; Matsumoto, H.; Mattiazzo, S.; Mazin, D.; McComb, T. J. L.; McCubbin, N.; McHardy, I.; Medina, C.; Melkumyan, D.; Mendes, A.; Mertsch, P.; Meucci, M.; Michałowski, J.; Micolon, P.; Mineo, T.; Mirabal, N.; Mirabel, F.; Miranda, J. M.; Mirzoyan, R.; Mizuno, T.; Moal, B.; Moderski, R.; Molinari, E.; Monteiro, I.; Moralejo, A.; Morello, C.; Mori, K.; Motta, G.; Mottez, F.; Moulin, E.; Mukherjee, R.; Munar, P.; Muraishi, H.; Murase, K.; Murphy, A. Stj.; Nagataki, S.; Naito, T.; Nakamori, T.; Nakayama, K.; Naumann, C.; Naumann, D.; Nayman, P.; Nedbal, D.; Niedźwiecki, A.; Niemiec, J.; Nikolaidis, A.; Nishijima, K.; Nolan, S. J.; Nowak, N.; O'Brien, P. T.; Ochoa, I.; Ohira, Y.; Ohishi, M.; Ohka, H.; Okumura, A.; Olivetto, C.; Ong, R. A.; Orito, R.; Orr, M.; Osborne, J. P.; Ostrowski, M.; Otero, L.; Otte, A. N.; Ovcharov, E.; Oya, I.; Oziȩbło, A.; Paiano, S.; Pallota, J.; Panazol, J. L.; Paneque, D.; Panter, M.; Paoletti, R.; Papyan, G.; Paredes, J. M.; Pareschi, G.; Parsons, R. D.; Paz Arribas, M.; Pedaletti, G.; Pepato, A.; Persic, M.; Petrucci, P. O.; Peyaud, B.; Piechocki, W.; Pita, S.; Pivato, G.; Płatos, Ł.; Platzer, R.; Pogosyan, L.; Pohl, M.; Pojmański, G.; Ponz, J. D.; Potter, W.; Prandini, E.; Preece, R.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quel, E.; Quirrenbach, A.; Rajda, P.; Rando, R.; Rataj, M.; Raue, M.; Reimann, C.; Reimann, O.; Reimer, A.; Reimer, O.; Renaud, M.; Renner, S.; Reymond, J.-M.; Rhode, W.; Ribó, M.; Ribordy, M.; Rico, J.; Rieger, F.; Ringegni, P.; Ripken, J.; Ristori, P.; Rivoire, S.; Rob, L.; Rodriguez, S.; Roeser, U.; Romano, P.; Romero, G. E.; Rosier-Lees, S.; Rovero, A. C.; Roy, F.; Royer, S.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Russo, F.; Ryde, F.; Sacco, B.; Saggion, A.; Sahakian, V.; Saito, K.; Saito, T.; Sakaki, N.; Salazar, E.; Salini, A.; Sánchez, F.; Sánchez Conde, M. Á.; Santangelo, A.; Santos, E. M.; Sanuy, A.; Sapozhnikov, L.; Sarkar, S.; Scalzotto, V.; Scapin, V.; Scarcioffolo, M.; Schanz, T.; Schlenstedt, S.; Schlickeiser, R.; Schmidt, T.; Schmoll, J.; Schroedter, M.; Schultz, C.; Schultze, J.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schweizer, T.; Seiradakis, J.; Selmane, S.; Seweryn, K.; Shayduk, M.; Shellard, R. C.; Shibata, T.; Sikora, M.; Silk, J.; Sillanpää, A.; Sitarek, J.; Skole, C.; Smith, N.; Sobczyńska, D.; Sofo Haro, M.; Sol, H.; Spanier, F.; Spiga, D.; Spyrou, S.; Stamatescu, V.; Stamerra, A.; Starling, R. L. C.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steiner, S.; Stergioulas, N.; Sternberger, R.; Stinzing, F.; Stodulski, M.; Straumann, U.; Suárez, A.; Suchenek, M.; Sugawara, R.; Sulanke, K. H.; Sun, S.; Supanitsky, A. D.; Sutcliffe, P.; Szanecki, M.; Szepieniec, T.; Szostek, A.; Szymkowiak, A.; Tagliaferri, G.; Tajima, H.; Takahashi, H.; Takahashi, K.; Takalo, L.; Takami, H.; Talbot, R. G.; Tam, P. H.; Tanaka, M.; Tanimori, T.; Tavani, M.; Tavernet, J.-P.; Tchernin, C.; Tejedor, L. A.; Telezhinsky, I.; Temnikov, P.; Tenzer, C.; Terada, Y.; Terrier, R.; Teshima, M.; Testa, V.; Tibaldo, L.; Tibolla, O.; Tluczykont, M.; Todero Peixoto, C. J.; Tokanai, F.; Tokarz, M.; Toma, K.; Torres, D. F.; Tosti, G.; Totani, T.; Toussenel, F.; Vallania, P.; Vallejo, G.; van der Walt, J.; van Eldik, C.; Vandenbroucke, J.; Vankov, H.; Vasileiadis, G.; Vassiliev, V. V.; Vegas, I.; Venter, L.; Vercellone, S.; Veyssiere, C.; Vialle, J. P.; Videla, M.; Vincent, P.; Vink, J.; Vlahakis, N.; Vlahos, L.; Vogler, P.; Vollhardt, A.; Volpe, F.; von Gunten, H. P.; Vorobiov, S.; Wagner, S.; Wagner, R. M.; Wagner, B.; Wakely, S. P.; Walter, P.; Walter, R.; Warwick, R.; Wawer, P.; Wawrzaszek, R.; Webb, N.; Wegner, P.; Weinstein, A.; Weitzel, Q.; Welsing, R.; Wetteskind, H.; White, R.; Wierzcholska, A.; Wilkinson, M. I.; Williams, D. A.; Winde, M.; Wischnewski, R.; Wiśniewski, Ł.; Wolczko, A.; Wood, M.; Xiong, Q.; Yamamoto, T.; Yamaoka, K.; Yamazaki, R.; Yanagita, S.; Yoffo, B.; Yonetani, M.; Yoshida, A.; Yoshida, T.; Yoshikoshi, T.; Zabalza, V.; Zagdański, A.; Zajczyk, A.; Zdziarski, A.; Zech, A.; Ziȩtara, K.; Ziółkowski, P.; Zitelli, V.; Zychowski, P.

2011-12-01

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

Thermal power and heat energy of cloud-to-ground lightning process

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

Wang, Xuejuan; Yuan, Ping; Xue, Simin

2016-07-15

A cloud-to-ground lightning flash with nine return strokes has been recorded using a high speed slitless spectrograph and a system composed of a fast antenna and a slow antenna. Based on the spectral data and the synchronous electric field changes that were caused by the lightning, the electrical conductivity, the channel radii, the resistance per unit length, the peak current, the thermal power at the instant of peak current, and the heat energy per unit length during the first 5 μs in the discharge channel have all been calculated. The results indicate that the channel radii have linear relationships with themore » peak current. The thermal power at the peak current time increases with increasing resistance, but exponential decays with the square of the peak current.« less

Estimation of electric fields and current from ground-based magnetometer data

NASA Technical Reports Server (NTRS)

Kamide, Y.; Richmond, A. D.

1984-01-01

Recent advances in numerical algorithms for estimating ionospheric electric fields and currents from groundbased magnetometer data are reviewed and evaluated. Tests of the adequacy of one such algorithm in reproducing large-scale patterns of electrodynamic parameters in the high-latitude ionosphere have yielded generally positive results, at least for some simple cases. Some encouraging advances in producing realistic conductivity models, which are a critical input, are pointed out. When the algorithms are applied to extensive data sets, such as the ones from meridian chain magnetometer networks during the IMS, together with refined conductivity models, unique information on instantaneous electric field and current patterns can be obtained. Examples of electric potentials, ionospheric currents, field-aligned currents, and Joule heating distributions derived from ground magnetic data are presented. Possible directions for future improvements are also pointed out.

A plan to study the aquifer system of the Central Valley of California

USGS Publications Warehouse

Bertoldi, Gilbert L.

1979-01-01

Unconsolidated Quaternary alluvial deposits comprise a large complex aquifer system in the Central Valley of California. Millions of acre-feet of water is pumped from the system annually to support a large and expanding agribusiness industry. Since the 1950's, water levels have been steadily declining in many areas of the valley and concern has been expressed about the ability of the entire ground-water system to support agribusiness at current levels, not to mention its ability to function at projected expansion levels. At current levels of ground-water use, an estimated 1.5 to 2 million acre-feet is withdrawn from storage each year; that is, 1.5 to 2 million acre-feet of water is pumped annually in excess of annual replenishment. The U.S. Geological Survey has initiated a 4-year study to develop geologic, hydrologic, and hydraulic information and to establish a valleywide ground-water data base that will be used to build computer models of the ground-water flow system. Subsequently, these models may be used to evaluate the system response to various ground-water management alternatives. This report describes current problems, objectives of the study, and outlines the general work to be accomplished in the study area. A bibliography of about 600 references is included. (Kosco-USGS)

Space Weather Effects Produced by the Ring Current Particles

NASA Astrophysics Data System (ADS)

Ganushkina, Natalia; Jaynes, Allison; Liemohn, Michael

2017-11-01

One of the definitions of space weather describes it as the time-varying space environment that may be hazardous to technological systems in space and/or on the ground and/or endanger human health or life. The ring current has its contributions to space weather effects, both in terms of particles, ions and electrons, which constitute it, and magnetic and electric fields produced and modified by it at the ground and in space. We address the main aspects of the space weather effects from the ring current starting with brief review of ring current discovery and physical processes and the Dst-index and predictions of the ring current and storm occurrence based on it. Special attention is paid to the effects on satellites produced by the ring current electrons. The ring current is responsible for several processes in the other inner magnetosphere populations, such as the plasmasphere and radiation belts which is also described. Finally, we discuss the ring current influence on the ionosphere and the generation of geomagnetically induced currents (GIC).

Diagnostic and model dependent uncertainty of simulated Tibetan permafrost area

NASA Astrophysics Data System (ADS)

Wang, W.; Rinke, A.; Moore, J. C.; Cui, X.; Ji, D.; Li, Q.; Zhang, N.; Wang, C.; Zhang, S.; Lawrence, D. M.; McGuire, A. D.; Zhang, W.; Delire, C.; Koven, C.; Saito, K.; MacDougall, A.; Burke, E.; Decharme, B.

2015-03-01

We perform a land surface model intercomparison to investigate how the simulation of permafrost area on the Tibetan Plateau (TP) varies between 6 modern stand-alone land surface models (CLM4.5, CoLM, ISBA, JULES, LPJ-GUESS, UVic). We also examine the variability in simulated permafrost area and distribution introduced by 5 different methods of diagnosing permafrost (from modeled monthly ground temperature, mean annual ground and air temperatures, air and surface frost indexes). There is good agreement (99-135 x 104 km2) between the two diagnostic methods based on air temperature which are also consistent with the best current observation-based estimate of actual permafrost area (101 x 104 km2). However the uncertainty (1-128 x 104 km2) using the three methods that require simulation of ground temperature is much greater. Moreover simulated permafrost distribution on TP is generally only fair to poor for these three methods (diagnosis of permafrost from monthly, and mean annual ground temperature, and surface frost index), while permafrost distribution using air temperature based methods is generally good. Model evaluation at field sites highlights specific problems in process simulations likely related to soil texture specification and snow cover. Models are particularly poor at simulating permafrost distribution using definition that soil temperature remains at or below 0°C for 24 consecutive months, which requires reliable simulation of both mean annual ground temperatures and seasonal cycle, and hence is relatively demanding. Although models can produce better permafrost maps using mean annual ground temperature and surface frost index, analysis of simulated soil temperature profiles reveals substantial biases. The current generation of land surface models need to reduce biases in simulated soil temperature profiles before reliable contemporary permafrost maps and predictions of changes in permafrost distribution can be made for the Tibetan Plateau.

Study of Fluid Experiment System (FES)/CAST/Holographic Ground System (HGS)

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Cummings, Rick; Jones, Brian

1992-01-01

The use of holographic and schlieren optical techniques for studying the concentration gradients in solidification processes has been used by several investigators over the years. The HGS facility at MSFC has been primary resource in researching this capability. Consequently, scientific personnel have been able to utilize these techniques in both ground based research and in space experiments. An important event in the scientific utilization of the HGS facilities was the TGS Crystal Growth and the casting and solidification technology (CAST) experiments that were flown on the International Microgravity Laboratory (IML) mission in March of this year. The preparation and processing of these space observations are the primary experiments reported in this work. This project provides some ground-based studies to optimize on the holographic techniques used to acquire information about the crystal growth processes flown on IML. Since the ground-based studies will be compared with the space-based experimental results, it is necessary to conduct sufficient ground based studies to best determine how the experiment worked in space. The current capabilities in computer based systems for image processing and numerical computation have certainly assisted in those efforts. As anticipated, this study has certainly shown that these advanced computing capabilities are helpful in the data analysis of such experiments.

International Low-Earth-Orbit Spacecraft Materials Test Program Initiated for Better Prediction of Durability and Performance

NASA Technical Reports Server (NTRS)

Rutledge, Sharon K.

1999-01-01

Spacecraft in low Earth orbit (LEO) are subjected to many components of the environment, which can cause them to degrade much more rapidly than intended and greatly shorten their functional life. The atomic oxygen, ultraviolet radiation, and cross contamination present in LEO can affect sensitive surfaces such as thermal control paints, multilayer insulation, solar array surfaces, and optical surfaces. The LEO Spacecraft Materials Test (LEO-SMT) program is being conducted to assess the effects of simulated LEO exposure on current spacecraft materials to increase understanding of LEO degradation processes as well as to enable the prediction of in-space performance and durability. Using ground-based simulation facilities to test the durability of materials currently flying in LEO will allow researchers to compare the degradation evidenced in the ground-based facilities with that evidenced on orbit. This will allow refinement of ground laboratory test systems and the development of algorithms to predict the durability and performance of new materials in LEO from ground test results. Accurate predictions based on ground tests could reduce development costs and increase reliability. The wide variety of national and international materials being tested represent materials being functionally used on spacecraft in LEO. The more varied the types of materials tested, the greater the probability that researchers will develop and validate predictive models for spacecraft long-term performance and durability. Organizations that are currently participating in the program are ITT Research Institute (USA), Lockheed Martin (USA), MAP (France), SOREQ Nuclear Research Center (Israel), TNO Institute of Applied Physics (The Netherlands), and UBE Industries, Ltd. (Japan). These represent some of the major suppliers of thermal control and sensor materials currently flying in LEO. The participants provide materials that are exposed to selected levels of atomic oxygen, vacuum ultraviolet radiation, contamination, or synergistic combined environments at the NASA Lewis Research Center. Changes in characteristics that could affect mission performance or lifetime are then measured. These characteristics include changes in mass, solar absorptance, and thermal emittance. The durability of spacecraft materials from U.S. suppliers is then compared with those of materials from other participating countries. Lewis will develop and validate performance and durability prediction models using this ground data and available space data. NASA welcomes the opportunity to consider additional international participants in this program, which should greatly aid future spacecraft designers as they select materials for LEO missions.

A synthetic GMPE based on deterministic simulated ground motion data obtained from dynamic rupture models

NASA Astrophysics Data System (ADS)

Dalguer, L. A.; Baumann, C.; Cauzzi, C.

2013-12-01

Empirical ground motion prediction in the very near-field and for large magnitudes is often based on extrapolation of ground motion prediction equations (GMPEs) outside the range where they are well constrained by recorded data. With empirical GMPEs it is also difficult to capture source-dominated ground motion patterns, such as the effects of velocity pulses induced by subshear and supershear rupture directivity, buried and surface-rupturing, hanging-wall and foot-wall, weak shallow layers, complex geometry faults and stress drop. A way to cope at least in part with these shortcomings is to augment the calibration datasets with synthetic ground motions. To this aim, physics-based dynamic rupture models - where the physical bases involved in the fault rupture are explicitly considered - appear to be a suitable approach to produce synthetic ground motions. In this contribution, we first perform an assessment of a database of synthetic ground motions generated by a suite of dynamic rupture simulations to verify compatibility of the peak ground amplitudes with current GMPEs. The synthetic data-set is composed by 360 earthquake scenarios with moment magnitudes in the range of 5.5-7, for three mechanisms of faulting (reverse, normal and strike-slip) and for both buried faults and surface rupturing faults. Second, we parameterise the synthetic dataset through a GMPE. For this purpose, we identify the basic functional forms by analyzing the variation of the synthetic peak ground motions and spectral ordinates as a function of different explanatory variables related to the earthquake source characteristics, in order to account for some of the source effects listed above. We argue that this study provides basic guidelines for the developments of future GMPEs including data from physics-based numerical simulations.

Protection Method of Biological Lightning Safety around Power Grid Based on Grounding Electrode Structure

NASA Astrophysics Data System (ADS)

Sixiang, Chen; Daopin, Chen; Ming, Zhang; Xiao, Huang; Jian, He; Zhijie, He

2017-05-01

Aimed at the actual situation of fish death in fish ponds near the power transmission line towers after the thunderstorm happened in Guangdong Province in China, this paper studied the influence of the ground current on fish in the pond. Firstly, This paper studied the current density of the fish without protection. On this basis, paper studied the horizontal pole with full-shielded, the vertical pole with half-shielded, the horizontal pole with extension three kinds of protective measures and effects. Finally an effective protection scheme was put forward according to the engineering practice. The results can provide some engineering guidance and quantitative basis for the design and modification of grounding devices when the tower is adjacent to the fish ponds in southern China.

30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... separate grounding conductor located within the trailing cable of mobile and portable equipment and... conductor located within the direct-current power cable feeding stationary equipment and connected between... ground conductor connected between stationary equipment and the direct-current grounding medium; or, (d...

30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... separate grounding conductor located within the trailing cable of mobile and portable equipment and... conductor located within the direct-current power cable feeding stationary equipment and connected between... ground conductor connected between stationary equipment and the direct-current grounding medium; or, (d...

30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... separate grounding conductor located within the trailing cable of mobile and portable equipment and... conductor located within the direct-current power cable feeding stationary equipment and connected between... ground conductor connected between stationary equipment and the direct-current grounding medium; or, (d...

30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... separate grounding conductor located within the trailing cable of mobile and portable equipment and... conductor located within the direct-current power cable feeding stationary equipment and connected between... ground conductor connected between stationary equipment and the direct-current grounding medium; or, (d...

30 CFR 75.703-3 - Approved methods of grounding offtrack mobile, portable and stationary direct-current machines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... separate grounding conductor located within the trailing cable of mobile and portable equipment and... conductor located within the direct-current power cable feeding stationary equipment and connected between... ground conductor connected between stationary equipment and the direct-current grounding medium; or, (d...

Ground-based lidar for atmospheric boundary layer ozone measurements.

PubMed

Kuang, Shi; Newchurch, Michael J; Burris, John; Liu, Xiong

2013-05-20

Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than ±10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

Evaluation of culture- and PCR-based detection methods for Escherichia coli O157:H7 in inoculated ground beeft.

PubMed

Arthur, Terrance M; Bosilevac, Joseph M; Nou, Xiangwu; Koohmaraie, Mohammad

2005-08-01

Currently, several beef processors employ test-and-hold systems for increased quality control of ground beef. In such programs, each lot of product must be tested and found negative for Escherichia coli O157:H7 prior to release of the product into commerce. Optimization of three testing attributes (detection time, specificity, and sensitivity) is critical to the success of such strategies. Because ground beef is a highly perishable product, the testing methodology used must be as rapid as possible. The test also must have a low false-positive result rate so product is not needlessly discarded. False-negative results cannot be tolerated because they would allow contaminated product to be released and potentially cause disease. In this study, two culture-based and three PCR-based methods for detecting E. coli O157:H7 in ground beef were compared for their abilities to meet the above criteria. Ground beef samples were individually spiked with five genetically distinct strains of E. coli O157: H7 at concentrations of 17 and 1.7 CFU/65 g and then subjected to the various testing methodologies. There was no difference (P > 0.05) in the abilities of the PCR-based methods to detect E. coli O157:H7 inoculated in ground beef at 1.7 CFU/65 g. The culture-based systems detected more positive samples than did the PCR-based systems, but the detection times (21 to 48 h) were at least 9 h longer than those for the PCR-based methods (7.5 to 12 h). Ground beef samples were also spiked with potentially cross-reactive strains. The PCR-based systems that employed an immunomagnetic separation step prior to detection produced fewer false-positive results.

Combining GOES-16 Geostationary Lightning Mapper with the ground based Earth Networks Total Lightning Network

NASA Astrophysics Data System (ADS)

Stock, M.; Lapierre, J. L.; Zhu, Y.

2017-12-01

Recently, the Geostationary Lightning Mapper (GLM) began collecting optical data to locate lightning events and flashes over the North and South American continents. This new instrument promises uniformly high detection efficiency (DE) over its entire field of view, with location accuracy on the order of 10 km. In comparison, Earth Networks Total Lightning Networks (ENTLN) has a less uniform coverage, with higher DE in regions with dense sensor coverage, and lower DE with sparse sensor coverage. ENTLN also offers better location accuracy, lightning classification, and peak current estimation for their lightning locations. It is desirable to produce an integrated dataset, combining the strong points of GLM and ENTLN. The easiest way to achieve this is to simply match located lightning processes from each system using time and distance criteria. This simple method will be limited in scope by the uneven coverage of the ground based network. Instead, we will use GLM group locations to look up the electric field change data recorded by ground sensors near each GLM group, vastly increasing the coverage of the ground network. The ground waveforms can then be used for: improvements to differentiation between glint and lightning for GLM, higher precision lighting location, current estimation, and lightning process classification. Presented is an initial implementation of this type of integration using preliminary GLM data, and waveforms from ENTLN.

Regional 3-D Modeling of Ground Geoelectric Field for the Northeast United States due to Realistic Geomagnetic Disturbances

NASA Astrophysics Data System (ADS)

Ivannikova, E.; Kruglyakov, M.; Kuvshinov, A. V.; Rastaetter, L.; Pulkkinen, A. A.; Ngwira, C. M.

2017-12-01

During extreme space weather events electric currents in the Earth's magnetosphere and ionosphere experience large variations, which leads to dramatic intensification of the fluctuating magnetic field at the surface of the Earth. According to Faraday's law of induction, the fluctuating geomagnetic field in turn induces electric field that generates harmful currents (so-called "geomagnetically induced currents"; GICs) in grounded technological systems. Understanding (via modeling) of the spatio-temporal evolution of the geoelectric field during enhanced geomagnetic activity is a key consideration in estimating the hazard to technological systems from space weather. We present the results of ground geoelectric field modeling for the Northeast United States, which is performed with the use of our novel numerical tool based on integral equation approach. The tool exploits realistic regional three-dimensional (3-D) models of the Earth's electrical conductivity and realistic global models of the spatio-temporal evolution of the magnetospheric and ionospheric current systems responsible for geomagnetic disturbances. We also explore in detail the manifestation of the coastal effect (anomalous intensification of the geoelectric field near the coasts) in this region.

ULTIMA: Array of ground-based magnetometer arrays for monitoring magnetospheric and ionospheric perturbations on a global scale

NASA Astrophysics Data System (ADS)

Yumoto, K.; Chi, P. J.; Angelopoulos, V.; Connors, M. G.; Engebretson, M. J.; Fraser, B. J.; Mann, I. R.; Milling, D. K.; Moldwin, M. B.; Russell, C. T.; Stolle, C.; Tanskanen, E.; Vallante, M.; Yizengaw, E.; Zesta, E.

2012-12-01

ULTIMA (Ultra Large Terrestrial International Magnetic Array) is an international consortium that aims at promoting collaborative research on the magnetosphere, ionosphere, and upper atmosphere through the use of ground-based magnetic field observatories. ULTIMA is joined by individual magnetometer arrays in different countries/regions, and the current regular-member arrays are Australian, AUTUMN, CARISMA, DTU Space, Falcon, IGPP-LANL, IMAGE, MACCS, MAGDAS, McMAC, MEASURE, THEMIS, and SAMBA. The Chair of ULTIMA has been K. Yumoto (MAGDAS), and its Secretary has been P. Chi (McMAC, Falcon). In this paper we perform case studies in which we estimate the global patterns of (1) near-Earth currents and (2) magnetic pulsations; these phenomena are observed over wide areas on the ground, thus suitable for the aims of ULTIMA. We analyze these two phenomena during (a) quiet period and (b) magnetic storm period. We compare the differences between these two periods by drawing the global maps of the ionospheric equivalent currents (which include the effects of all the near-Earth currents) and pulsation amplitudes. For ionospheric Sq currents at low latitudes during quiet periods, MAGDAS data covering an entire solar cycle has yielded a detailed statistical model, and we can use it as a reference for the aforementioned comparison. We also estimate the azimuthal wave numbers of pulsations and compare the amplitude distribution of pulsations with the distribution of highly energetic (in MeV range) particles simultaneously observed at geosynchronous satellites.

Army Airships

DTIC Science & Technology

2011-04-01

is accredited by the Commission on Higher Education of the Middle States Association of Colleges and Schools, 3624 Market Street, Philadelphia, PA...designed to be interoperable with the Army‟s Universal Ground Control Station ( UGCS ) and uses the same hardware and software as the UGCS .12 Part of the...efforts face similar basing, launch and recovery and ground support requirements. Currently, the LEMV program has adapted for use the UGCS used by all

30 CFR 75.814 - Electrical protection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... protection must not be dependent upon control power and may consist of a current transformer and overcurrent... restarting of the equipment. (b) Current transformers used for the ground-fault protection specified in... series with ground-fault current transformers. (c) Each ground-fault current device specified in...

30 CFR 75.814 - Electrical protection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... protection must not be dependent upon control power and may consist of a current transformer and overcurrent... restarting of the equipment. (b) Current transformers used for the ground-fault protection specified in... series with ground-fault current transformers. (c) Each ground-fault current device specified in...

30 CFR 75.814 - Electrical protection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... protection must not be dependent upon control power and may consist of a current transformer and overcurrent... restarting of the equipment. (b) Current transformers used for the ground-fault protection specified in... series with ground-fault current transformers. (c) Each ground-fault current device specified in...

30 CFR 75.814 - Electrical protection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... protection must not be dependent upon control power and may consist of a current transformer and overcurrent... restarting of the equipment. (b) Current transformers used for the ground-fault protection specified in... series with ground-fault current transformers. (c) Each ground-fault current device specified in...

30 CFR 75.814 - Electrical protection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... protection must not be dependent upon control power and may consist of a current transformer and overcurrent... restarting of the equipment. (b) Current transformers used for the ground-fault protection specified in... series with ground-fault current transformers. (c) Each ground-fault current device specified in...

Ground penetrating radar for underground sensing in agriculture: a review

NASA Astrophysics Data System (ADS)

Liu, Xiuwei; Dong, Xuejun; Leskovar, Daniel I.

2016-10-01

Belowground properties strongly affect agricultural productivity. Traditional methods for quantifying belowground properties are destructive, labor-intensive and pointbased. Ground penetrating radar can provide non-invasive, areal, and repeatable underground measurements. This article reviews the application of ground penetrating radar for soil and root measurements and discusses potential approaches to overcome challenges facing ground penetrating radar-based sensing in agriculture, especially for soil physical characteristics and crop root measurements. Though advanced data-analysis has been developed for ground penetrating radar-based sensing of soil moisture and soil clay content in civil engineering and geosciences, it has not been used widely in agricultural research. Also, past studies using ground penetrating radar in root research have been focused mainly on coarse root measurement. Currently, it is difficult to measure individual crop roots directly using ground penetrating radar, but it is possible to sense root cohorts within a soil volume grid as a functional constituent modifying bulk soil dielectric permittivity. Alternatively, ground penetrating radarbased sensing of soil water content, soil nutrition and texture can be utilized to inversely estimate root development by coupling soil water flow modeling with the seasonality of plant root growth patterns. Further benefits of ground penetrating radar applications in agriculture rely on the knowledge, discovery, and integration among differing disciplines adapted to research in agricultural management.

Comparison of Airborne and Ground-Based Function Allocation Concepts for NextGen Using Human-In-The-Loop Simulations

NASA Technical Reports Server (NTRS)

Wing, David J.; Prevot, Thomas; Murdoch, Jennifer L.; Cabrall, Christopher D.; Homola, Jeffrey R.; Martin, Lynne H.; Mercer, Joey S.; Hoadley, Sherwood T.; Wilson, Sara R.; Hubbs, Clay E.;

Estimates of ground-water recharge, base flow, and stream reach gains and losses in the Willamette River basin, Oregon

USGS Publications Warehouse

Lee, Karl K.; Risley, John C.

2002-03-19

Precipitation-runoff models, base-flow-separation techniques, and stream gain-loss measurements were used to study recharge and ground-water surface-water interaction as part of a study of the ground-water resources of the Willamette River Basin. The study was a cooperative effort between the U.S. Geological Survey and the State of Oregon Water Resources Department. Precipitation-runoff models were used to estimate the water budget of 216 subbasins in the Willamette River Basin. The models were also used to compute long-term average recharge and base flow. Recharge and base-flow estimates will be used as input to a regional ground-water flow model, within the same study. Recharge and base-flow estimates were made using daily streamflow records. Recharge estimates were made at 16 streamflow-gaging-station locations and were compared to recharge estimates from the precipitation-runoff models. Base-flow separation methods were used to identify the base-flow component of streamflow at 52 currently operated and discontinued streamflow-gaging-station locations. Stream gain-loss measurements were made on the Middle Fork Willamette, Willamette, South Yamhill, Pudding, and South Santiam Rivers, and were used to identify and quantify gaining and losing stream reaches both spatially and temporally. These measurements provide further understanding of ground-water/surface-water interactions.

Acute health impacts of airborne particles estimated from satellite remote sensing.

PubMed

Wang, Zhaoxi; Liu, Yang; Hu, Mu; Pan, Xiaochuan; Shi, Jing; Chen, Feng; He, Kebin; Koutrakis, Petros; Christiani, David C

2013-01-01

Satellite-based remote sensing provides a unique opportunity to monitor air quality from space at global, continental, national and regional scales. Most current research focused on developing empirical models using ground measurements of the ambient particulate. However, the application of satellite-based exposure assessment in environmental health is still limited, especially for acute effects, because the development of satellite PM(2.5) model depends on the availability of ground measurements. We tested the hypothesis that MODIS AOD (aerosol optical depth) exposure estimates, obtained from NASA satellites, are directly associated with daily health outcomes. Three independent healthcare databases were used: unscheduled outpatient visits, hospital admissions, and mortality collected in Beijing metropolitan area, China during 2006. We use generalized linear models to compare the short-term effects of air pollution assessed by ground monitoring (PM(10)) with adjustment of absolute humidity (AH) and AH-calibrated AOD. Across all databases we found that both AH-calibrated AOD and PM(10) (adjusted by AH) were consistently associated with elevated daily events on the current day and/or lag days for cardiovascular diseases, ischemic heart diseases, and COPD. The relative risks estimated by AH-calibrated AOD and PM(10) (adjusted by AH) were similar. Additionally, compared to ground PM(10), we found that AH-calibrated AOD had narrower confidence intervals for all models and was more robust in estimating the current day and lag day effects. Our preliminary findings suggested that, with proper adjustment of meteorological factors, satellite AOD can be used directly to estimate the acute health impacts of ambient particles without prior calibrating to the sparse ground monitoring networks. Copyright © 2012 Elsevier Ltd. All rights reserved.

Operational efficiency subpanel advanced mission control

NASA Technical Reports Server (NTRS)

Friedland, Peter

1990-01-01

Herein, the term mission control will be taken quite broadly to include both ground and space based operations as well as the information infrastructure necessary to support such operations. Three major technology areas related to advanced mission control are examined: (1) Intelligent Assistance for Ground-Based Mission Controllers and Space-Based Crews; (2) Autonomous Onboard Monitoring, Control and Fault Detection Isolation and Reconfiguration; and (3) Dynamic Corporate Memory Acquired, Maintained, and Utilized During the Entire Vehicle Life Cycle. The current state of the art space operations are surveyed both within NASA and externally for each of the three technology areas and major objectives are discussed from a user point of view for technology development. Ongoing NASA and other governmental programs are described. An analysis of major research issues and current holes in the program are provided. Several recommendations are presented for enhancing the technology development and insertion process to create advanced mission control environments.

Design Concepts for the Cherenkov Telescope Array CTA: An Advanced Facility for Ground-Based High-Energy Gamma-Ray Astronomy

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

Actis, M

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTAmore » is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.« less

The challenge of mapping the human connectome based on diffusion tractography.

PubMed

Maier-Hein, Klaus H; Neher, Peter F; Houde, Jean-Christophe; Côté, Marc-Alexandre; Garyfallidis, Eleftherios; Zhong, Jidan; Chamberland, Maxime; Yeh, Fang-Cheng; Lin, Ying-Chia; Ji, Qing; Reddick, Wilburn E; Glass, John O; Chen, David Qixiang; Feng, Yuanjing; Gao, Chengfeng; Wu, Ye; Ma, Jieyan; Renjie, H; Li, Qiang; Westin, Carl-Fredrik; Deslauriers-Gauthier, Samuel; González, J Omar Ocegueda; Paquette, Michael; St-Jean, Samuel; Girard, Gabriel; Rheault, François; Sidhu, Jasmeen; Tax, Chantal M W; Guo, Fenghua; Mesri, Hamed Y; Dávid, Szabolcs; Froeling, Martijn; Heemskerk, Anneriet M; Leemans, Alexander; Boré, Arnaud; Pinsard, Basile; Bedetti, Christophe; Desrosiers, Matthieu; Brambati, Simona; Doyon, Julien; Sarica, Alessia; Vasta, Roberta; Cerasa, Antonio; Quattrone, Aldo; Yeatman, Jason; Khan, Ali R; Hodges, Wes; Alexander, Simon; Romascano, David; Barakovic, Muhamed; Auría, Anna; Esteban, Oscar; Lemkaddem, Alia; Thiran, Jean-Philippe; Cetingul, H Ertan; Odry, Benjamin L; Mailhe, Boris; Nadar, Mariappan S; Pizzagalli, Fabrizio; Prasad, Gautam; Villalon-Reina, Julio E; Galvis, Justin; Thompson, Paul M; Requejo, Francisco De Santiago; Laguna, Pedro Luque; Lacerda, Luis Miguel; Barrett, Rachel; Dell'Acqua, Flavio; Catani, Marco; Petit, Laurent; Caruyer, Emmanuel; Daducci, Alessandro; Dyrby, Tim B; Holland-Letz, Tim; Hilgetag, Claus C; Stieltjes, Bram; Descoteaux, Maxime

2017-11-07

Tractography based on non-invasive diffusion imaging is central to the study of human brain connectivity. To date, the approach has not been systematically validated in ground truth studies. Based on a simulated human brain data set with ground truth tracts, we organized an open international tractography challenge, which resulted in 96 distinct submissions from 20 research groups. Here, we report the encouraging finding that most state-of-the-art algorithms produce tractograms containing 90% of the ground truth bundles (to at least some extent). However, the same tractograms contain many more invalid than valid bundles, and half of these invalid bundles occur systematically across research groups. Taken together, our results demonstrate and confirm fundamental ambiguities inherent in tract reconstruction based on orientation information alone, which need to be considered when interpreting tractography and connectivity results. Our approach provides a novel framework for estimating reliability of tractography and encourages innovation to address its current limitations.

A New Large-Well 1024x1024 Si:As Detector for the Mid-Infrared

NASA Technical Reports Server (NTRS)

Mainzer, Amanda K.; Hong, John H.; Stapelbroek, M. G.; Hogue, Henry; Molyneux, Dale; Ressler, Michael E.; Watkins, Ernie; Reekstin, John; Werner, Mike; Young, Erick

2005-01-01

We present a description of a new 1024x1024 Si:As array designed for ground-based use from 5 - 28 microns. With a maximum well depth of 5e6 electrons, this device brings large-format array technology to bear on ground-based mid-infrared programs, allowing entry to the mega-pixel realm previously only accessible to the near-IR. The multiplexer design features switchable gain, a 256x256 windowing mode for extremely bright sources, and it is two-edge buttable. The device is currently in its final design phase at DRS in Cypress, CA. We anticipate completion of the foundry run in October 2005. This new array will enable wide field, high angular resolution ground-based follow up of targets found by space-based missions such as the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE).

A model for characterizing residential ground current and magnetic field fluctuations.

PubMed

Mader, D L; Peralta, S B; Sherar, M D

1994-01-01

The current through the residential grounding circuit is an important source for magnetic fields; field variations near the grounding circuit accurately track fluctuations in this ground current. In this paper, a model is presented which permits calculation of the range of these fluctuations. A discrete network model is used to simulate a local distribution system for a single street, and a statistical model to simulate unbalanced currents in the system. Simulations of three-house and ten-house networks show that random appliance operation leads to ground current fluctuations which can be quite large, on the order of 600%. This is consistent with measured fluctuations in an actual house.

Instruments, Detectors and the Future of Astronomy with Large Ground Based Telescopes

NASA Astrophysics Data System (ADS)

Simons, Douglas A.; Amico, Paola; Baade, Dietrich; Barden, Sam; Campbell, Randall; Finger, Gert; Gilmore, Kirk; Gredel, Roland; Hickson, Paul; Howell, Steve; Hubin, Norbert; Kaufer, Andreas; Kohley, Ralf; MacQueen, Philip; Markelov, Sergej; Merrill, Mike; Miyazaki, Satoshi; Nakaya, Hidehiko; O'Donoghue, Darragh; Oliva, Tino; Richichi, Andrea; Salmon, Derrick; Schmidt, Ricardo; Su, Hongjun; Tulloch, Simon; García Vargas, Maria Luisa; Wagner, R. Mark; Wiecha, Olivier; Ye, Binxun

2005-01-01

Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 109 pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors - something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future.

NASA ground-based and space-based laser ranging systems

NASA Technical Reports Server (NTRS)

Fitzmaurice, M. W.

1978-01-01

Laser ranging is expected to help unlock the mysteries of the earthquake phenomenon by producing unique results of crustal motions of the Earth. The current state of the art and future projections are presented, including principal applications and characteristics of typical systems.

Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 1: Generic ground operations data

NASA Technical Reports Server (NTRS)

Byrd, Raymond J.

1990-01-01

This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advance Launch System (ALS) program, the results of the Operationally Efficient Propulsion System Study (OEPSS) were organized into a series of OEPSS Data Books as follows: Volume 1, Generic Ground Operations Data; Volume 2, Ground Operations Problems; Volume 3, Operations Technology; Volume 4, OEPSS Design Concepts; and Volume 5, OEPSS Final Review Briefing, which summarizes the activities and results of the study. This volume presents ground processing data for a generic LOX/LH2 booster and core propulsion system based on current STS experience. The data presented includes: top logic diagram, process flow, activities bar-chart, loaded timelines, manpower requirements in terms of duration, headcount and skill mix per operations and maintenance instruction (OMI), and critical path tasks and durations.

Astrometric surveys in the Gaia era

NASA Astrophysics Data System (ADS)

Zacharias, Norbert

2018-04-01

The Gaia first data release (DR1) already provides an almost error free optical reference frame on the milli-arcsecond (mas) level allowing significantly better calibration of ground-based astrometric data than ever before. Gaia DR1 provides positions, proper motions and trigonometric parallaxes for just over 2 million stars in the Tycho-2 catalog. For over 1.1 billion additional stars DR1 gives positions. Proper motions for these, mainly fainter stars (G >= 11.5) are currently provided by several new projects which combine earlier epoch ground-based observations with Gaia DR1 positions. These data are very helpful in the interim period but will become obsolete with the second Gaia data release (DR2) expected in April 2018. The era of traditional, ground-based, wide-field astrometry with the goal to provide accurate reference stars has come to an end. Future ground-based astrometry will fill in some gaps (very bright stars, observations needed at many or specific epochs) and mainly will go fainter than the Gaia limit, like the PanSTARRS and the upcoming LSST surveys.

30 CFR 75.701-3 - Approved methods of grounding metallic frames, casings and other enclosures of electric equipment...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., casings and other enclosures of electric equipment receiving power from direct current power systems with... equipment receiving power from direct current power systems with one polarity grounded. For the purpose of... direct-current power system with one polarity grounded, the following methods of grounding will be...

30 CFR 75.701-3 - Approved methods of grounding metallic frames, casings and other enclosures of electric equipment...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., casings and other enclosures of electric equipment receiving power from direct current power systems with... equipment receiving power from direct current power systems with one polarity grounded. For the purpose of... direct-current power system with one polarity grounded, the following methods of grounding will be...

30 CFR 75.701-3 - Approved methods of grounding metallic frames, casings and other enclosures of electric equipment...

Code of Federal Regulations, 2013 CFR

2013-07-01

..., casings and other enclosures of electric equipment receiving power from direct current power systems with... equipment receiving power from direct current power systems with one polarity grounded. For the purpose of... direct-current power system with one polarity grounded, the following methods of grounding will be...

30 CFR 75.701-3 - Approved methods of grounding metallic frames, casings and other enclosures of electric equipment...

Code of Federal Regulations, 2014 CFR

2014-07-01

..., casings and other enclosures of electric equipment receiving power from direct current power systems with... equipment receiving power from direct current power systems with one polarity grounded. For the purpose of... direct-current power system with one polarity grounded, the following methods of grounding will be...

30 CFR 75.701-3 - Approved methods of grounding metallic frames, casings and other enclosures of electric equipment...

Code of Federal Regulations, 2012 CFR

2012-07-01

..., casings and other enclosures of electric equipment receiving power from direct current power systems with... equipment receiving power from direct current power systems with one polarity grounded. For the purpose of... direct-current power system with one polarity grounded, the following methods of grounding will be...

An Ethic of Democratic, Curriculum-Based Teacher Leadership

ERIC Educational Resources Information Center

Castner, Daniel J.; Schneider, Jennifer L.; Henderson, James G.

2017-01-01

This article opens with an overview of the current policy interest in "teacher leadership" with its particular challenges and opportunities. Teacher-leader interpretations based on standardized instructional management platforms grounded in neoliberalism are critically challenged. The referent for this critical questioning is a normative…

The terrestrial ring current - From in situ measurements to global images using energetic neutral atoms

NASA Technical Reports Server (NTRS)

Roelof, Edmond C.; Williams, Donald J.

1988-01-01

Electrical currents flowing in the equatorial magnetosphere, first inferred from ground-based magnetic disturbances, are carried by trapped energetic ions. Spacecraft measurements have determined the spectrum and composition of those currents, and the newly developed technique of energetic-neutral-atom imaging allows the global dynamics of that entire ion population to be viewed from a single spacecraft.

Warranty-Guarantee Application Guidelines for Air Force Ground Electronic Equipment.

DTIC Science & Technology

1980-02-01

perform the on-equipment maintenance. The procedure is comparable to existing Mobile Depot Mainte- nance. The extended outage of failed equipment may be...currently computed. However, because the equipment is fixed geographically, in contrast to the mobility of avionics equipment, operating-time logs could...base environment, many other items of ground equip- ment are deployed at a remote location or, particularly in TAC, may be mobile equipment not

Transuranic Waste Program Framework Agreement - December Deliverable July 2012

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

Jones, Patricia

Framework agreement deliverables are: (1) 'DOE/NNSA commits to complete removal of all non-cemented above-ground EM Legacy TRU and newly generated TRU currently-stored at Area G as of October 1, 2011, by no later than June 30, 2014. This inventory of above-ground TRU is defined as 3706 cubic meters of material.' (2) 'DOE commits to the complete removal of all newly generated TRU received in Area G during FY 2012 and 2013 by no later than December 31, 2014.' (3) 'Based on projected funding profiles, DOE/NNSA will develop by December 31, 2012, a schedule, including pacing milestones, for disposition of themore » below-ground TRU requiring retrieval at Area G.' Objectives are to: (1) restore the 'Core Team' to develop the December, 2012 deliverable; (2) obtain agreement on the strategy for below ground water disposition; and (3) establish timeline for completion of the deliverable. Below Grade Waste Strategy is to: (1) Perform an evaluation on below grade waste currently considered retrievable TRU; (2) Only commit to retrieve waste that must be retrieved; (3) Develop the Deliverable including Pacing Milestones based on planned commitments; (4) Align all Regulatory Documents for Consistency; and (5) answer these 3 primary questions, is the waste TRU; is the waste retrievable, can retrieval cause more harm than benefit?« less

Eco-sustainable systems based on poly(lactic acid), diatomite and coffee grounds extract for food packaging.

PubMed

Cacciotti, Ilaria; Mori, Stefano; Cherubini, Valeria; Nanni, Francesca

2018-06-01

In the food packaging sector many efforts have been (and are) devoted to the development of new materials in order to reply to an urgent market demand for green and eco-sustainable products. Particularly a lot of attention is currently devoted both to the use of compostable and biobased polymers as innovative and promising alternative to the currently used petrochemical derived polymers, and to the re-use of waste materials coming from agriculture and food industry. In this work, multifunctional eco-sustainable systems, based on poly(lactic acid) (PLA) as biopolymeric matrix, diatomaceous earth as reinforcing filler and spent coffee grounds extract as oxygen scavenger, were produced for the first time, in order to provide a simultaneous improvement of mechanical and gas barrier properties. The influence of the diatomite and the spent coffee grounds extract on the microstructural, mechanical and oxygen barrier properties of the produced films was deeply investigated by means of X-Ray diffraction (XRD), infrared spectroscopy (FT-IR, ATR), scanning electron microscopy (SEM), uniaxial tensile tests, O 2 permeabilimetry measurements. An improvement of both mechanical and oxygen barrier properties was recorded for systems characterised by the co-presence of diatomite and coffee grounds extract, suggesting a possible synergic effect of the two additives. Copyright © 2018 Elsevier B.V. All rights reserved.

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2011 CFR

2011-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral...-1 Approved methods of grounding of equipment receiving power from ungrounded alternating current... receiving power from ungrounded alternating current power systems, the following methods of grounding will...

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2010 CFR

2010-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral...-1 Approved methods of grounding of equipment receiving power from ungrounded alternating current... receiving power from ungrounded alternating current power systems, the following methods of grounding will...

Short-term Forecasting Ground Magnetic Perturbations with the Space Weather Modeling Framework

NASA Astrophysics Data System (ADS)

Welling, Daniel; Toth, Gabor; Gombosi, Tamas; Singer, Howard; Millward, George

2016-04-01

Predicting ground-based magnetic perturbations is a critical step towards specifying and predicting geomagnetically induced currents (GICs) in high voltage transmission lines. Currently, the Space Weather Modeling Framework (SWMF), a flexible modeling framework for simulating the multi-scale space environment, is being transitioned from research to operational use (R2O) by NOAA's Space Weather Prediction Center. Upon completion of this transition, the SWMF will provide localized dB/dt predictions using real-time solar wind observations from L1 and the F10.7 proxy for EUV as model input. This presentation describes the operational SWMF setup and summarizes the changes made to the code to enable R2O progress. The framework's algorithm for calculating ground-based magnetometer observations will be reviewed. Metrics from data-model comparisons will be reviewed to illustrate predictive capabilities. Early data products, such as regional-K index and grids of virtual magnetometer stations, will be presented. Finally, early successes will be shared, including the code's ability to reproduce the recent March 2015 St. Patrick's Day Storm.

46 CFR 120.370 - General grounding requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... hull must not carry current as a conductor except for the following systems: (1) Impressed current... grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

46 CFR 120.370 - General grounding requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... hull must not carry current as a conductor except for the following systems: (1) Impressed current... grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

46 CFR 120.370 - General grounding requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... hull must not carry current as a conductor except for the following systems: (1) Impressed current... grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

46 CFR 120.370 - General grounding requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... hull must not carry current as a conductor except for the following systems: (1) Impressed current... grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

46 CFR 120.370 - General grounding requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... hull must not carry current as a conductor except for the following systems: (1) Impressed current... grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

Flapping current sheet with superposed waves seen in space and on the ground

NASA Astrophysics Data System (ADS)

Wang, G. Q.; Volwerk, M.; Nakamura, R.; Boakes, P.; Zhang, T. L.; Yoshikawa, A.; Baishev, D. G.

2014-12-01

A wavy current sheet event observed on 15 October 2004 between 1235 and 1300 UT has been studied by using Cluster and ground-based magnetometer data. Waves propagating from the tail center to the duskside flank with a period ~30 s and wavelength ~1 RE are superimposed on a flapping current sheet, accompanied with a bursty bulk flow. Three Pi2 pulsations, with onset at ~1236, ~1251, and ~1255 UT, respectively, are observed at the Tixie station located near the foot points of Cluster. The mechanism creating the Pi2 (period ~40 s) onset at ~1236 UT is unclear. The second Pi2 (period ~90 s, onset at ~1251 UT) is associated with a strong field-aligned current, which has a strong transverse component of the magnetic field, observed by Cluster with a time delay ~60 s. We suggest that it is caused by bouncing Alfvén waves between the northern and southern ionosphere which transport the field-aligned current. For the third Pi2 (period ~60 s) there is almost no damping at the first three periods. They occur in conjunction with periodic field-aligned currents one-on-one with 72 s delay. We suggest that it is generated by these periodic field-aligned currents. We conclude that the strong field-aligned currents generated in the plasma sheet during flapping with superimposed higher-frequency waves can drive Pi2 pulsations on the ground, and periodic field-aligned currents can even control the period of the Pi2s.

Plant diversity to support humans in a CELSS ground based demonstrator

NASA Technical Reports Server (NTRS)

Howe, J. M.; Hoff, J. E.

1981-01-01

A controlled ecological life support system (CELSS) for human habitation in preparation for future long duration space flights is considered. The success of such a system depends upon the feasibility of revitalization of food resources and the human nutritional needs which are to be met by these food resources. Edible higher plants are prime candidates for the photoautotrophic components of this system if nutritionally adequate diets can be derived from these plant sources to support humans. Human nutritional requirements information based on current knowledge are developed for inhabitants envisioned in the CELSS ground based demonstrator. Groups of plant products that can provide the nutrients are identified.

Associating ground magnetometer observations with current or voltage generators

NASA Astrophysics Data System (ADS)

Hartinger, M. D.; Xu, Z.; Clauer, C. R.; Yu, Y.; Weimer, D. R.; Kim, H.; Pilipenko, V.; Welling, D. T.; Behlke, R.; Willer, A. N.

2017-07-01

A circuit analogy for magnetosphere-ionosphere current systems has two extremes for drivers of ionospheric currents: ionospheric electric fields/voltages constant while current/conductivity vary—the "voltage generator"—and current constant while electric field/conductivity vary—the "current generator." Statistical studies of ground magnetometer observations associated with dayside Transient High Latitude Current Systems (THLCS) driven by similar mechanisms find contradictory results using this paradigm: some studies associate THLCS with voltage generators, others with current generators. We argue that most of this contradiction arises from two assumptions used to interpret ground magnetometer observations: (1) measurements made at fixed position relative to the THLCS field-aligned current and (2) negligible auroral precipitation contributions to ionospheric conductivity. We use observations and simulations to illustrate how these two assumptions substantially alter expectations for magnetic perturbations associated with either a current or a voltage generator. Our results demonstrate that before interpreting ground magnetometer observations of THLCS in the context of current/voltage generators, the location of a ground magnetometer station relative to the THLCS field-aligned current and the location of any auroral zone conductivity enhancements need to be taken into account.

Development Of Eej Model Based On Dense Ground-based Magnetometer Array

NASA Astrophysics Data System (ADS)

Matsushita, H.; Yoshikawa, A.; Uozumi, T.; Fujimoto, A.; Abe, S.; Ishitsuka I, J. K.; Veliz, O.; Rosales, D.; Safor, E.; Beteta, V.

2016-12-01

Equatorial Electro-jet(here after called EEJ) is the electric current which flows very narrow region in ionosphere of the earth, which is between +- 3 degree from dip latitude. The EEJ was noticed as the significant enhancement of daily variation of magnetic field, and later Hirono, (1950) explained it by adapting Cowling effect to the ionosphere of the earth. The EE index, is one of ICSWSE space weather indices, was developed by Uozumi et al., (2008). Then, ICSWSE has continued to monitor the EEJ activity by using this EE index. Fujimoto et al., (2016) investigated the relationship between solar activity and long term variation of EEJ, and Hamid et al., (2015) investigated longitudinal dependency of EEJ, both of them were based on EE index. The EE index provides EDst value, which is correspond to magnetic field change at dip equator caused by magnetospheric current such as ring current, and EUEL value, which is correspond to the one caused by ionospheric current such as EEJ and Sq. However, actual EEJ is not magnetic field but the current, and it has not only current intensity but also the width. Some previous paper reported the EEJ structure such as current density or the width of EEJ using satellite data (e.g. Lühr et al., 2004; Jadhav et al., 2002), which is good when it checks the longitudinal dependency because it shifts longitude in a day. However, the ground-based magnetometer may be well useful to investigate the day-to-day variability of EEJ because it is fixed to same location. So, we developed a model of EEJ, which can estimate the EEJ current structure by ground magnetometer using dense magnetometer array near dip equator. In this study, the EEJ structures along 75W and 135E longitude are represented, and are compared each other. The result shows that large standard deviation of both current density and the half width are identified, while previous studies reported constant half width (e.g. Lühr et al., 2004). When our EEJ model is compared with CM4 model, which was developed by Sabaka et al., (2004), large discrepancy between them was identified, so it should be more discussed the reason to produce more accurate EEJ model.

49 CFR 236.2 - Grounds.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., single-break, signal control circuits using a grounded common, and alternating current power distribution...) Alternating current power distribution circuits that are grounded in the interest of safety. ...

Surge current and electron swarm tunnel tests of thermal blanket and ground strap materials

NASA Technical Reports Server (NTRS)

Hoffmaster, D. K.; Inouye, G. T.; Sellen, J. M., Jr.

1977-01-01

The results are described of a series of current conduction tests with a thermal control blanket to which grounding straps have been attached. The material and the ground strap attachment procedure are described. The current conduction tests consisted of a surge current examination of the ground strap and a dilute flow, energetic electron deposition and transport through the bulk of the insulating film of this thermal blanket material. Both of these test procedures were used previously with thermal control blanket materials.

Practical Applications for Earthquake Scenarios Using ShakeMap

NASA Astrophysics Data System (ADS)

Wald, D. J.; Worden, B.; Quitoriano, V.; Goltz, J.

2001-12-01

In planning and coordinating emergency response, utilities, local government, and other organizations are best served by conducting training exercises based on realistic earthquake situations-ones that they are most likely to face. Scenario earthquakes can fill this role; they can be generated for any geologically plausible earthquake or for actual historic earthquakes. ShakeMap Web pages now display selected earthquake scenarios (www.trinet.org/shake/archive/scenario/html) and more events will be added as they are requested and produced. We will discuss the methodology and provide practical examples where these scenarios are used directly for risk reduction. Given a selected event, we have developed tools to make it relatively easy to generate a ShakeMap earthquake scenario using the following steps: 1) Assume a particular fault or fault segment will (or did) rupture over a certain length, 2) Determine the magnitude of the earthquake based on assumed rupture dimensions, 3) Estimate the ground shaking at all locations in the chosen area around the fault, and 4) Represent these motions visually by producing ShakeMaps and generating ground motion input for loss estimation modeling (e.g., FEMA's HAZUS). At present, ground motions are estimated using empirical attenuation relationships to estimate peak ground motions on rock conditions. We then correct the amplitude at that location based on the local site soil (NEHRP) conditions as we do in the general ShakeMap interpolation scheme. Finiteness is included explicitly, but directivity enters only through the empirical relations. Although current ShakeMap earthquake scenarios are empirically based, substantial improvements in numerical ground motion modeling have been made in recent years. However, loss estimation tools, HAZUS for example, typically require relatively high frequency (3 Hz) input for predicting losses, above the range of frequencies successfully modeled to date. Achieving full-synthetic ground motion estimates that will substantially improve over empirical relations at these frequencies will require developing cost-effective numerical tools for proper theoretical inclusion of known complex ground motion effects. Current efforts underway must continue in order to obtain site, basin, and deeper crustal structure, and to characterize and test 3D earth models (including attenuation and nonlinearity). In contrast, longer period synthetics (>2 sec) are currently being generated in a deterministic fashion to include 3D and shallow site effects, an improvement on empirical estimates alone. As progress is made, we will naturally incorporate such advances into the ShakeMap scenario earthquake and processing methodology. Our scenarios are currently used heavily in emergency response planning and loss estimation. Primary users include city, county, state and federal government agencies (e.g., the California Office of Emergency Services, FEMA, the County of Los Angeles) as well as emergency response planners and managers for utilities, businesses, and other large organizations. We have found the scenarios are also of fundamental interest to many in the media and the general community interested in the nature of the ground shaking likely experienced in past earthquakes as well as effects of rupture on known faults in the future.

Electrical Methods: Resistivity Methods

EPA Pesticide Factsheets

Surface electrical resistivity surveying is based on the principle that the distribution of electrical potential in the ground around a current-carrying electrode depends on the electrical resistivities and distribution of the surrounding soils and rocks.

Starting From Ground Zero

ERIC Educational Resources Information Center

Fischer, William B.; Stauffer, Robert A.

1978-01-01

Erie County Community College (New York) has developed a zero-based program budgeting system to meet current fiscal problems and diminished resources. The system allocates resources on the basis of program effectiveness and market potential. (LH)

Solar multi-conjugate adaptive optics based on high order ground layer adaptive optics and low order high altitude correction.

PubMed

Zhang, Lanqiang; Guo, Youming; Rao, Changhui

2017-02-20

Multi-conjugate adaptive optics (MCAO) is the most promising technique currently developed to enlarge the corrected field of view of adaptive optics for astronomy. In this paper, we propose a new configuration of solar MCAO based on high order ground layer adaptive optics and low order high altitude correction, which result in a homogeneous correction effect in the whole field of view. An individual high order multiple direction Shack-Hartmann wavefront sensor is employed in the configuration to detect the ground layer turbulence for low altitude correction. Furthermore, the other low order multiple direction Shack-Hartmann wavefront sensor supplies the wavefront information caused by high layers' turbulence through atmospheric tomography for high altitude correction. Simulation results based on the system design at the 1-meter New Vacuum Solar Telescope show that the correction uniform of the new scheme is obviously improved compared to conventional solar MCAO configuration.

49 CFR 234.213 - Grounds.

Code of Federal Regulations, 2014 CFR

2014-10-01

...: circuits that include track rail; alternating current power distribution circuits that are grounded in the...) Circuits that include track rail; (2) Alternating current power distribution circuits that are grounded in...

Tritium as an indicator of ground-water age in Central Wisconsin

USGS Publications Warehouse

Bradbury, Kenneth R.

1991-01-01

In regions where ground water is generally younger than about 30 years, developing the tritium input history of an area for comparison with the current tritium content of ground water allows quantitative estimates of minimum ground-water age. The tritium input history for central Wisconsin has been constructed using precipitation tritium measured at Madison, Wisconsin and elsewhere. Weighted tritium inputs to ground water reached a peak of over 2,000 TU in 1964, and have declined since that time to about 20-30 TU at present. In the Buena Vista basin in central Wisconsin, most ground-water samples contained elevated levels of tritium, and estimated minimum ground-water ages in the basin ranged from less than one year to over 33 years. Ground water in mapped recharge areas was generally younger than ground water in discharge areas, and estimated ground-water ages were consistent with flow system interpretations based on other data. Estimated minimum ground-water ages increased with depth in areas of downward ground-water movement. However, water recharging through thick moraine sediments was older than water in other recharge areas, reflecting slower infiltration through the sandy till of the moraine.

30 CFR 75.824 - Electrical protection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... transformer and over-current relay in the neutral grounding resistor circuit. (vi) A single window-type current transformer that encircles all three-phase conductors must be used to activate the ground-fault... current transformer. (vii) A test circuit for the ground-fault device must be provided. The test circuit...

30 CFR 75.824 - Electrical protection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... transformer and over-current relay in the neutral grounding resistor circuit. (vi) A single window-type current transformer that encircles all three-phase conductors must be used to activate the ground-fault... current transformer. (vii) A test circuit for the ground-fault device must be provided. The test circuit...

30 CFR 75.824 - Electrical protection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... transformer and over-current relay in the neutral grounding resistor circuit. (vi) A single window-type current transformer that encircles all three-phase conductors must be used to activate the ground-fault... current transformer. (vii) A test circuit for the ground-fault device must be provided. The test circuit...

30 CFR 75.824 - Electrical protection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... transformer and over-current relay in the neutral grounding resistor circuit. (vi) A single window-type current transformer that encircles all three-phase conductors must be used to activate the ground-fault... current transformer. (vii) A test circuit for the ground-fault device must be provided. The test circuit...

30 CFR 75.824 - Electrical protection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... transformer and over-current relay in the neutral grounding resistor circuit. (vi) A single window-type current transformer that encircles all three-phase conductors must be used to activate the ground-fault... current transformer. (vii) A test circuit for the ground-fault device must be provided. The test circuit...

Development of Ground Coils with Low Eddy Current Loss by Applying the Compression Molding Method after the Coil Winding

NASA Astrophysics Data System (ADS)

Suzuki, Masao; Aiba, Masayuki; Takahashi, Noriyuki; Ota, Satoru; Okada, Shigenori

In a magnetically levitated transportation (MAGLEV) system, a huge number of ground coils will be required because they must be laid for the whole line. Therefore, stable performance and reduced cost are essential requirements for the ground coil development. On the other hand, because the magnetic field changes when the superconducting magnet passes by, an eddy current will be generated in the conductor of the ground coil and will result in energy loss. The loss not only increases the magnetic resistance for the train running but also brings an increase in the ground coil temperature. Therefore, the reduction of the eddy current loss is extremely important. This study examined ground coils in which both the eddy current loss and temperature increase were small. Furthermore, quantitative comparison for the eddy current loss of various magnet wire samples was performed by bench test. On the basis of the comparison, a round twisted wire having low eddy current loss was selected as an effective ground coil material. In addition, the ground coils were manufactured on trial. A favorable outlook to improve the size accuracy of the winding coil and uneven thickness of molded resin was obtained without reducing the insulation strength between the coil layers by applying a compression molding after winding.

Advanced Fiber Optic-Based Sensing Technology for Unmanned Aircraft Systems

NASA Technical Reports Server (NTRS)

Richards, Lance; Parker, Allen R.; Piazza, Anthony; Ko, William L.; Chan, Patrick; Bakalyar, John

2011-01-01

This presentation provides an overview of fiber optic sensing technology development activities performed at NASA Dryden in support of Unmanned Aircraft Systems. Examples of current and previous work are presented in the following categories: algorithm development, system development, instrumentation installation, ground R&D, and flight testing. Examples of current research and development activities are provided.

AWPA biodeterioration hazard map revisited

Treesearch

Grant T. Kirker; Amy B. Bishell; William J. Hickey

2017-01-01

The fungal decay hazard map used by the American Wood Protection Association (AWPA) currently describes regional decay hazards in ground contact for North America and is based on condition assessments of utility poles from the 1970’s. Current work at the USDA Forest Service, Forest Products Laboratory is underway to analyze soil and wood samples from several National...

Credit BG. Interior view of the building displays temporary wooden ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. Interior view of the building displays temporary wooden building construction, pump, and water piping arrangements. The well is currently used as an observation post for changes in ground water levels - Edwards Air Force Base, North Base, Well No. 2, East of Second Street, Boron, Kern County, CA

Award-Winning Faculty at a Faith-Based Institution

ERIC Educational Resources Information Center

Livingston, Jennifer; Jun, Alexander

2011-01-01

Exploring the development of excellent teachers could contribute to the revision of current practices in faculty recruitment, evaluation, workload expectations, and reward systems. This grounded theory study examined the professional careers of nine award-winning faculty members of a faith-based institution of higher education. The data, collected…

Use of NDVI and land surface temperature for assessing vegetation health: merits and limitations

USDA-ARS?s Scientific Manuscript database

To date, most drought indices used in drought monitoring are based on precipitation and meteorological data collected on the ground from distributed monitoring networks. Few satellite-based drought indices are currently in production, although these afford better spatial and temporal coverage and r...

Constant-current regulator improves tunnel diode threshold-detector performance

NASA Technical Reports Server (NTRS)

Cancro, C. A.

1965-01-01

Grounded-base transistor is placed in a tunnel diode threshold detector circuit, and a bias voltage is applied to the tunnel diode. This provides the threshold detector with maximum voltage output and overload protection.

Research opportunities in space motion sickness, phase 2

NASA Technical Reports Server (NTRS)

Talbot, J. M.

1983-01-01

Space and motion sickness, the current and projected NASA research program, and the conclusions and suggestions of the ad hoc Working Group are summarized. The frame of reference for the report is ground-based research.

Hydrology with unmanned aerial vehicles (UAVs)

USDA-ARS?s Scientific Manuscript database

Hydrologic remote sensing currently depends on expensive and infrequent aircraft observations for validation of operational satellite products, typically conducted during field campaigns that also include ground-based measurements. With the advent of new, hydrologically-relevant satellite missions, ...

Connecting Authentic Activities with Multimedia to Enhance Teaching and Learning, an Exemplar from Scottish History

ERIC Educational Resources Information Center

Hillis, Peter

2010-01-01

Much of the current focus on maximizing the potential of ICT to enhance teaching and learning is on learning tasks rather than the technology. These learning tasks increasingly employ a constructivist, problem-based methodology especially one based around authentic learning. The problem-based nature of history provides fertile ground for this…

30 CFR 77.901-1 - Grounding resistor; continuous current rating.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Grounding resistor; continuous current rating. 77.901-1 Section 77.901-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.901-1 Grounding...

30 CFR 77.901-1 - Grounding resistor; continuous current rating.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding resistor; continuous current rating. 77.901-1 Section 77.901-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.901-1 Grounding...

30 CFR 77.901-1 - Grounding resistor; continuous current rating.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Grounding resistor; continuous current rating. 77.901-1 Section 77.901-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.901-1 Grounding...

30 CFR 77.901-1 - Grounding resistor; continuous current rating.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Grounding resistor; continuous current rating. 77.901-1 Section 77.901-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.901-1 Grounding...

30 CFR 77.901-1 - Grounding resistor; continuous current rating.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Grounding resistor; continuous current rating. 77.901-1 Section 77.901-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.901-1 Grounding...

Hydrogeologic Setting and Ground-Water Flow in the Leetown Area, West Virginia

USGS Publications Warehouse

Kozar, Mark D.; Weary, David J.; Paybins, Katherine S.; Pierce, Herbert A.

2007-01-01

The Leetown Science Center is a research facility operated by the U.S. Geological Survey that occupies approximately 455-acres near Kearneysville, Jefferson County, West Virginia. Aquatic and fish research conducted at the Center requires adequate supplies of high-quality, cold ground water. Three large springs and three production wells currently (in 2006) supply water to the Center. The recent construction of a second research facility (National Center for Cool and Cold Water Aquaculture) operated by the U.S. Department of Agriculture and co-located on Center property has placed additional demands on available water resources in the area. A three-dimensional steady-state finite-difference ground-water flow model was developed to simulate ground-water flow in the Leetown area and was used to assess the availability of ground water to sustain current and anticipated future demands. The model also was developed to test a conceptual model of ground-water flow in the complex karst aquifer system in the Leetown area. Due to the complexity of the karst aquifer system, a multidisciplinary research study was required to define the hydrogeologic setting. Geologic mapping, surface- and borehole-geophysical surveys, stream base-flow surveys, and aquifer tests were conducted to provide the hydrogeologic data necessary to develop and calibrate the model. It would not have been possible to develop a numerical model of the study area without the intensive data collection and methods developments components of the larger, more comprehensive hydrogeologic investigation. Results of geologic mapping and surface-geophysical surveys verified the presence of several prominent thrust faults and identified additional faults and other complex geologic structures (including overturned anticlines and synclines) in the area. These geologic structures are known to control ground-water flow in the region. Results of this study indicate that cross-strike faults and fracture zones are major avenues of ground-water flow. Prior to this investigation, the conceptual model of ground-water flow for the region focused primarily on bedding planes and strike-parallel faults and joints as controls on ground-water flow but did not recognize the importance of cross-strike faults and fracture zones that allow ground water to flow downgradient across or through less permeable geologic formations. Results of the ground-water flow simulation indicate that current operations at the Center do not substantially affect either streamflow (less than a 5-percent reduction in annual streamflow) or ground-water levels in the Leetown area under normal climatic conditions but potentially could have greater effects on streamflow during long-term drought (reduction in streamflow of approximately 14 percent). On the basis of simulation results, ground-water withdrawals based on the anticipated need for an additional 150 to 200 gal/min (gallons per minute) of water at the Center also would not seriously affect streamflow (less than 8 to 9 percent reduction in streamflow) or ground-water levels in the area during normal climatic conditions. During drought conditions, however, the effects of current ground-water withdrawals and anticipated additional withdrawals of 150 to 200 gal/min to augment existing supplies result in moderate to substantial declines in water levels of 0.5-1.2 feet (ft) in the vicinity of the Center's springs and production wells. Streamflow was predicted to be reduced locally by approximately 21 percent. Such withdrawals during a drought or prolonged period of below normal ground-water levels would result in substantial declines in the flow of the Center's springs and likely would not be sustainable for more than a few months. The drought simulated in this model was roughly equivalent to the more than 1-year drought that affected the region from November 1998 through February 2000. The potential reduction in streamflow is a result of capture of ground water tha

Hydrogeologic setting, hydraulic properties, and ground-water flow at the O-Field area of Aberdeen Proving Ground, Maryland

USGS Publications Warehouse

Banks, W.S.; Smith, B.S.; Donnelly, C.A.

1996-01-01

The U.S. Army disposed chemical agents, laboratory materials, and unexploded ordnance at O-Field in the Edgewood area of Aberdeen Proving Ground, Maryland, from before World War II until at least the 1950's. Soil, ground water, surface water,and wetland sediments in the O-Field area were contaminated from the disposal activity. A ground-water-flow model of the O-Field area was constructed by the U.S. Geological Survey (USGS) in 1989 to simulate flow in the central and southern part of the Gunpowder Neck. The USGS began an additional study of the contamination in the O-Field area in cooperation with the U.S. Army in 1990 to (1) further define the hydrogeologic framework of the O-Field area, (2) characterize the hydraulic properties of the aquifers and confining units, and (3) define ground-water flow paths at O-Field based on the current data and simulations of ground-water flow. A water-table aquifer, an upper confining unit, and an upper confined aquifer comprise the shallow ground-water aquifer system of the O-Field area. A lower confining unit, through which ground-water movement is negligible, is considered a lower boundary to the shallow aquifer system. These units are all part of the Pleistocene Talbot Formation. The model developed in the previous study was redesigned using the data collected during this study and emphasized New O-Field. The current steady-state model was calibrated to water levels of June 1993. The rate of ground-water flow calculated by the model was approximately 0.48 feet per day (ft/d) and the rate determined from chlorofluorocarbon dates was approximately 0.39 ft/d.

An open repository of earthquake-triggered ground-failure inventories

USGS Publications Warehouse

Schmitt, Robert G.; Tanyas, Hakan; Nowicki Jessee, M. Anna; Zhu, Jing; Biegel, Katherine M.; Allstadt, Kate E.; Jibson, Randall W.; Thompson, Eric M.; van Westen, Cees J.; Sato, Hiroshi P.; Wald, David J.; Godt, Jonathan W.; Gorum, Tolga; Xu, Chong; Rathje, Ellen M.; Knudsen, Keith L.

2017-12-20

Earthquake-triggered ground failure, such as landsliding and liquefaction, can contribute significantly to losses, but our current ability to accurately include them in earthquake-hazard analyses is limited. The development of robust and widely applicable models requires access to numerous inventories of ground failures triggered by earthquakes that span a broad range of terrains, shaking characteristics, and climates. We present an openly accessible, centralized earthquake-triggered groundfailure inventory repository in the form of a ScienceBase Community to provide open access to these data with the goal of accelerating research progress. The ScienceBase Community hosts digital inventories created by both U.S. Geological Survey (USGS) and non-USGS authors. We present the original digital inventory files (when available) as well as an integrated database with uniform attributes. We also summarize the mapping methodology and level of completeness as reported by the original author(s) for each inventory. This document describes the steps taken to collect, process, and compile the inventories and the process for adding additional ground-failure inventories to the ScienceBase Community in the future.

Evaluation on surface current observing network of high frequency ground wave radars in the Gulf of Thailand

NASA Astrophysics Data System (ADS)

Yin, Xunqiang; Shi, Junqiang; Qiao, Fangli

2018-05-01

Due to the high cost of ocean observation system, the scientific design of observation network becomes much important. The current network of the high frequency radar system in the Gulf of Thailand has been studied using a three-dimensional coastal ocean model. At first, the observations from current radars have been assimilated into this coastal model and the forecast results have improved due to the data assimilation. But the results also show that further optimization of the observing network is necessary. And then, a series of experiments were carried out to assess the performance of the existing high frequency ground wave radar surface current observation system. The simulated surface current data in three regions were assimilated sequentially using an efficient ensemble Kalman filter data assimilation scheme. The experimental results showed that the coastal surface current observation system plays a positive role in improving the numerical simulation of the currents. Compared with the control experiment without assimilation, the simulation precision of surface and subsurface current had been improved after assimilated the surface currents observed at current networks. However, the improvement for three observing regions was quite different and current observing network in the Gulf of Thailand is not effective and a further optimization is required. Based on these evaluations, a manual scheme has been designed by discarding the redundant and inefficient locations and adding new stations where the performance after data assimilation is still low. For comparison, an objective scheme based on the idea of data assimilation has been obtained. Results show that all the two schemes of observing network perform better than the original network and optimal scheme-based data assimilation is much superior to the manual scheme that based on the evaluation of original observing network in the Gulf of Thailand. The distributions of the optimal network of radars could be a useful guidance for future design of observing system in this region.

Ground-based facilities for simulation of microgravity: organism-specific recommendations for their use, and recommended terminology.

PubMed

Herranz, Raul; Anken, Ralf; Boonstra, Johannes; Braun, Markus; Christianen, Peter C M; de Geest, Maarten; Hauslage, Jens; Hilbig, Reinhard; Hill, Richard J A; Lebert, Michael; Medina, F Javier; Vagt, Nicole; Ullrich, Oliver; van Loon, Jack J W A; Hemmersbach, Ruth

2013-01-01

Research in microgravity is indispensable to disclose the impact of gravity on biological processes and organisms. However, research in the near-Earth orbit is severely constrained by the limited number of flight opportunities. Ground-based simulators of microgravity are valuable tools for preparing spaceflight experiments, but they also facilitate stand-alone studies and thus provide additional and cost-efficient platforms for gravitational research. The various microgravity simulators that are frequently used by gravitational biologists are based on different physical principles. This comparative study gives an overview of the most frequently used microgravity simulators and demonstrates their individual capacities and limitations. The range of applicability of the various ground-based microgravity simulators for biological specimens was carefully evaluated by using organisms that have been studied extensively under the conditions of real microgravity in space. In addition, current heterogeneous terminology is discussed critically, and recommendations are given for appropriate selection of adequate simulators and consistent use of nomenclature.

Spatial correlation of auroral zone geomagnetic variations

NASA Astrophysics Data System (ADS)

Jackel, B. J.; Davalos, A.

2016-12-01

Magnetic field perturbations in the auroral zone are produced by a combination of distant ionospheric and local ground induced currents. Spatial and temporal structure of these currents is scientifically interesting and can also have a significant influence on critical infrastructure.Ground-based magnetometer networks are an essential tool for studying these phenomena, with the existing complement of instruments in Canada providing extended local time coverage. In this study we examine the spatial correlation between magnetic field observations over a range of scale lengths. Principal component and canonical correlation analysis are used to quantify relationships between multiple sites. Results could be used to optimize network configurations, validate computational models, and improve methods for empirical interpolation.

Sensor web enables rapid response to volcanic activity

USGS Publications Warehouse

Davies, Ashley G.; Chien, Steve; Wright, Robert; Miklius, Asta; Kyle, Philip R.; Welsh, Matt; Johnson, Jeffrey B.; Tran, Daniel; Schaffer, Steven R.; Sherwood, Robert

2006-01-01

Rapid response to the onset of volcanic activity allows for the early assessment of hazard and risk [Tilling, 1989]. Data from remote volcanoes and volcanoes in countries with poor communication infrastructure can only be obtained via remote sensing [Harris et al., 2000]. By linking notifications of activity from ground-based and spacebased systems, these volcanoes can be monitored when they erupt.Over the last 18 months, NASA's Jet Propulsion Laboratory (JPL) has implemented a Volcano Sensor Web (VSW) in which data from ground-based and space-based sensors that detect current volcanic activity are used to automatically trigger the NASA Earth Observing 1 (EO-1) spacecraft to make highspatial-resolution observations of these volcanoes.

Human skeletal muscle responses to spaceflight and possible countermeasures

NASA Technical Reports Server (NTRS)

Gollnick, Philip D.; Edgerton, V. Reggie; Saltin, Bengt

1990-01-01

The current status of knowledge concerning the effects of unweighting skeletal muscle is summarized. The results of both ground-based and space-based animal studies are reviewed which show that there is rapid loss in muscle mass, primarily in slow-twitch muscle, of the rat during unweighting of muscle. There is also a shift in the myosin isoforms with muscles such that slow-twitch muscles take on many of the characteristics of fast-twitch muscles. Ground-based studies in human suggest that programs of electrical stimulation can be developed to simulate normal muscular contractions. Attempts to develop countermeasures to the adverse effects of space travel on muscular functions in humans have not been successful to date.

Flapping current sheet with superposed waves seen in space and on the ground

NASA Astrophysics Data System (ADS)

Wang, Guoqiang; Volwerk, Martin; Nakamura, Rumi; Boakes, Peter; Zhang, Tielong; Ge, Yasong; Yoshikawa, Akimasa; Baishev, Dmitry

2015-04-01

A wavy current sheet event observed on 15th of October 2004 between 1235 and 1300 UT has been studied by using Cluster and ground-based magnetometer data. Waves propagating from the tail centre to the duskside flank with a period ~30 s and wavelength ~1 RE, are superimposed on a flapping current sheet, accompanied with a bursty bulk flow (BBF). Three Pi2 pulsations, with onset at ~1236, ~1251 and ~1255 UT, respectively, are observed at the Tixie (TIK) station located near the foot-points of Cluster. The mechanism creating the Pi2 (period ~40 s) onset at ~1236 UT is unclear. The second Pi2 (period ~90 s, onset at ~1251 UT) is associated with a strong field-aligned current, which has a strong transverse component of the magnetic field, observed by Cluster with a time delay ~60 s. We suggest that it is caused by bouncing Alfvén waves between the northern and southern ionosphere which transport the field-aligned current. For the third Pi2 (period ~60 s) there is almost no damping at the first three periods. They occur in conjunction with periodic field-aligned currents one-on-one with 72s delay. We suggest that it is generated by these periodic field-aligned currents. We conclude that the strong field-aligned currents generated in the plasma sheet during flapping with superimposed higher frequency waves can drive Pi2 pulsations on the ground, and periodic field-aligned currents can even control the period of the Pi2s.

A Fast Method for Embattling Optimization of Ground-Based Radar Surveillance Network

NASA Astrophysics Data System (ADS)

Jiang, H.; Cheng, H.; Zhang, Y.; Liu, J.

A growing number of space activities have created an orbital debris environment that poses increasing impact risks to existing space systems and human space flight. For the safety of in-orbit spacecraft, a lot of observation facilities are needed to catalog space objects, especially in low earth orbit. Surveillance of Low earth orbit objects are mainly rely on ground-based radar, due to the ability limitation of exist radar facilities, a large number of ground-based radar need to build in the next few years in order to meet the current space surveillance demands. How to optimize the embattling of ground-based radar surveillance network is a problem to need to be solved. The traditional method for embattling optimization of ground-based radar surveillance network is mainly through to the detection simulation of all possible stations with cataloged data, and makes a comprehensive comparative analysis of various simulation results with the combinational method, and then selects an optimal result as station layout scheme. This method is time consuming for single simulation and high computational complexity for the combinational analysis, when the number of stations increases, the complexity of optimization problem will be increased exponentially, and cannot be solved with traditional method. There is no better way to solve this problem till now. In this paper, target detection procedure was simplified. Firstly, the space coverage of ground-based radar was simplified, a space coverage projection model of radar facilities in different orbit altitudes was built; then a simplified objects cross the radar coverage model was established according to the characteristics of space objects orbit motion; after two steps simplification, the computational complexity of the target detection was greatly simplified, and simulation results shown the correctness of the simplified results. In addition, the detection areas of ground-based radar network can be easily computed with the simplified model, and then optimized the embattling of ground-based radar surveillance network with the artificial intelligent algorithm, which can greatly simplifies the computational complexities. Comparing with the traditional method, the proposed method greatly improved the computational efficiency.

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2013 CFR

2013-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral... power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power systems, the following methods of grounding will...

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2012 CFR

2012-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral... power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power systems, the following methods of grounding will...

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2014 CFR

2014-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral... power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power systems, the following methods of grounding will...

The influence of p-doping on two-state lasing in InAs/InGaAs quantum dot lasers

NASA Astrophysics Data System (ADS)

Maximov, M. V.; Shernyakov, Yu M.; Zubov, F. I.; Zhukov, A. E.; Gordeev, N. Yu; Korenev, V. V.; Savelyev, A. V.; Livshits, D. A.

2013-10-01

Two-state lasing in devices based on undoped and p-type modulation-doped InAs/InGaAs quantum dots is studied for various cavity lengths and temperatures. Modulation doping of the active region strongly enhances the threshold current of two-state lasing, preserves ground-state lasing up to higher temperatures and increases ground-state output power. The impact of modulation doping is especially strong in short cavities.

Physics in Astronomy--The Current Frontier.

ERIC Educational Resources Information Center

Robson, Ian

1991-01-01

Discussed are some of the topics at the forefront of modern astronomical research. Topics include quasars, black holes, and the beginning of the universe. The uses and types of telescopes are described, both spaceborn and ground based. (KR)

Correlation of coastal water turbidity and current circulation with ERTS-1 and Skylab imagery

NASA Technical Reports Server (NTRS)

Klemas, V.; Otley, M.; Philpot, W.; Wethe, C.; Rogers, R.; Shah, N.

1974-01-01

The article reviews investigations of current circulation patterns, suspended sediment concentration, coastal frontal systems, and waste disposal plumes based on visual interpretation and digital analysis of ERTS-1 and Skylab/EREP imagery. Data on conditions in the Delaware Bay area were obtained from 10 ERTS-1 passes and one Skylab pass, with simultaneous surface and airborne sensing. The current patterns and sediments observed by ERTS-1 correlated well with ground-based observations. Methods are suggested which would make it possible to identify certain pollutants and sediment types from multispectral scanner data.

Simulation of Ground-Water Flow in the Irwin Basin Aquifer System, Fort Irwin National Training Center, California

USGS Publications Warehouse

Densmore, Jill N.

2003-01-01

Ground-water pumping in the Irwin Basin at Fort Irwin National Training Center, California resulted in water-level declines of about 30 feet from 1941 to 1996. Since 1992, artificial recharge from wastewater-effluent infiltration and irrigation-return flow has stabilized water levels, but there is concern that future water demands associated with expansion of the base may cause a resumption of water-level declines. To address these concerns, a ground-water flow model of the Irwin Basin was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Historical data show that ground-water-level declines in the Irwin Basin between 1941 and 1996, caused the formation of a pumping depression near the pumped wells, and that recharge from the wastewater-treatment facility and disposal area caused the formation of a recharge mound. There have been two periods of water-level recovery in the Irwin Basin since the development of ground water in this basin; these periods coincide with a period of decreased pumpage from the basin and a period of increased recharge of water imported from the Bicycle Basin beginning in 1967 and from the Langford Basin beginning in 1992. Since 1992, artificial recharge has exceeded pumpage in the Irwin Basin and has stabilized water-level declines. A two-layer ground-water flow model was developed to help better understand the aquifer system, assess the long-term availability and quality of ground water, and evaluate ground-water conditions owing to current pumping and to plan for future water needs at the base. Boundary conditions, hydraulic conductivity, altitude of the bottom of the layers, vertical conductance, storage coefficient, recharge, and discharge were determined using existing geohydrologic data. Rates and distribution of recharge and discharge were determined from existing data and estimated when unavailable. Results of predictive simulations indicate that in 50 years, if artificial recharge continues to exceed pumpage in Irwin Basin, water levels could rise as much as 65 feet beneath the pumping depression, and as much as 10 feet in the wastewater-treatment facility and disposal area. Particle-tracking simulations were used to determine the pathlines and the traveltimes of water high in dissolved solids into the main pumping area. The pathlines of particles from two areas with high dissolved-solids concentrations show that in 50 years water from these areas almost reaches the nearest pumped well.

Classification of Initial conditions required for Substorm prediction.

NASA Astrophysics Data System (ADS)

Patra, S.; Spencer, E. A.

2014-12-01

We investigate different classes of substorms that occur as a result of various drivers such as the conditions in the solar wind and the internal state of the magnetosphere ionosphere system during the geomagnetic activity. In performing our study, we develop and use our low order physics based nonlinear model of the magnetosphere called WINDMI to establish the global energy exchange between the solar wind, magnetosphere and ionosphere by constraining the model results to satellite and ground measurements. On the other hand, we make quantitative and qualitative comparisons between our low order model with available MHD, multi-fluid and ring current simulations in terms of the energy transfer between the geomagnetic tail, plasma sheet, field aligned currents, ionospheric currents and ring current, during isolated substorms, storm time substorms, and sawtooth events. We use high resolution solar wind data from the ACE satellite, measurements from the CLUSTER and THEMIS missions satellites, and ground based magnetometer measurements from SUPERMAG and WDC Kyoto, to further develop our low order physics based model. Finally, we attempt to answer the following questions: 1) What conditions in the solar wind influence the type of substorm event. This includes the IMF strength and orientation, the particle densities, velocities and temperatures, and the timing of changes such as shocks, southward turnings or northward turnings of the IMF. 2) What is the state of the magnetosphere ionosphere system before an event begins. These are the steady state conditions prior to an event, if they exist, which produce the satellite and ground based measurements matched to the WINDMI model. 3) How does the prior state of the magnetosphere influence the transition into a particular mode of behavior under solar wind forcing. 4) Is it possible to classify the states of the magnetosphere into distinct categories depending on pre-conditioning, and solar wind forcing conditions? 5) Can we predict the occurrence of substorms with any confidence?

Autonomous Mission Operations Roadmap

NASA Technical Reports Server (NTRS)

Frank, Jeremy David

2014-01-01

As light time delays increase, the number of such situations in which crew autonomy is the best way to conduct the mission is expected to increase. However, there are significant open questions regarding which functions to allocate to ground and crew as the time delays increase. In situations where the ideal solution is to allocate responsibility to the crew and the vehicle, a second question arises: should the activity be the responsibility of the crew or an automated vehicle function? More specifically, we must answer the following questions: What aspects of mission operation responsibilities (Plan, Train, Fly) should be allocated to ground based or vehicle based planning, monitoring, and control in the presence of significant light-time delay between the vehicle and the Earth?How should the allocated ground based planning, monitoring, and control be distributed across the flight control team and ground system automation? How should the allocated vehicle based planning, monitoring, and control be distributed between the flight crew and onboard system automation?When during the mission should responsibility shift from flight control team to crew or from crew to vehicle, and what should the process of shifting responsibility be as the mission progresses? NASA is developing a roadmap of capabilities for Autonomous Mission Operations for human spaceflight. This presentation will describe the current state of development of this roadmap, with specific attention to in-space inspection tasks that crews might perform with minimum assistance from the ground.

The Earth Observing System (EOS) Ground System: Leveraging an Existing Operational Ground System Infrastructure to Support New Missions

NASA Technical Reports Server (NTRS)

Hardison, David; Medina, Johnny; Dell, Greg

2016-01-01

The Earth Observer System (EOS) was officially established in 1990 and went operational in December 1999 with the launch of its flagship spacecraft Terra. Aqua followed in 2002 and Aura in 2004. All three spacecraft are still operational and producing valuable scientific data. While all are beyond their original design lifetime, they are expected to remain viable well into the 2020s. The EOS Ground System is a multi-mission system based at NASA Goddard Space Flight Center that supports science and spacecraft operations for these three missions. Over its operational lifetime to date, the EOS Ground System has evolved as needed to accommodate mission requirements. With an eye towards the future, several updates are currently being deployed. Subsystem interconnects are being upgraded to reduce data latency and improve system performance. End-of-life hardware and operating systems are being replaced to mitigate security concerns and eliminate vendor support gaps. Subsystem hardware is being consolidated through the migration to Virtual Machine based platforms. While mission operations autonomy was not a design goal of the original system concept, there is an active effort to apply state-of-the-art products from the Goddard Mission Services Evolution Center (GMSEC) to facilitate automation where possible within the existing heritage architecture. This presentation will provide background information on the EOS ground system architecture and evolution, discuss latest improvements, and conclude with the results of a recent effort that investigated how the current system could accommodate a proposed new earth science mission.

Literacy and Young Children: Research-Based Practices. Solving Problems in the Teaching of Literacy.

ERIC Educational Resources Information Center

Barone, Diane M., Ed.; Morrow, Lesley Mandel, Ed.

This book presents current, research-based best practices for supporting young children's development as readers and writers. From leading figures in early literacy, the book's essays demonstrate that scientifically grounded instruction need not be dull, drill-oriented, or "one-size-fits-all"--rather, it describes language-rich approaches to…

The Credentials of Brain-Based Learning

ERIC Educational Resources Information Center

Davis, Andrew

2004-01-01

This paper discusses the current fashion for brain-based learning, in which value-laden claims about learning are grounded in neurophysiology. It argues that brain science cannot have the authority about learning that some seek to give it. It goes on to discuss whether the claim that brain science is relevant to learning involves a category…

Research Base for Improved Classroom Learning: Brain or Behavior? Evidence Speaks Reports, Vol 1, #9

ERIC Educational Resources Information Center

Bruer, John T.

2015-01-01

Implicit in recent Evidence Speaks postings is the need to develop evidence-based interventions for improving student achievement. Comparative analysis of the education research literature versus the educational neuroscience literature suggests that education research, grounded in the behavioral and cognitive sciences, is currently the better…

Swift observations of SDSS J141118.31+481257.6 during superoutburst

NASA Astrophysics Data System (ADS)

Rivera Sandoval, L. E.; Maccarone, T.

2018-06-01

We report on follow-up Swift observations of the AM CVn-type binary SDSS J141118.31+481257.6 (ATEL #11668, #11672). Based on ground based photometry, the re-brightening previous to the current superoutburst was reported on 2018-June-1 (https://www.aavso.org/aavso-alert-notice-636).

Guidance for Schools Selecting Antibullying Approaches: Translating Evidence-Based Strategies to Contemporary Implementation Realities

ERIC Educational Resources Information Center

Ansary, Nadia S.; Elias, Maurice J.; Greene, Michael B.; Green, Stuart

2015-01-01

This article synthesizes the current research on bullying prevention and intervention in order to provide guidance to schools seeking to select and implement antibullying strategies. Evidence-based best practices that are shared across generally effective antibullying approaches are elucidated, and these strategies are grounded in examples…

Site Selection for Hvdc Ground Electrodes

NASA Astrophysics Data System (ADS)

Freire, P. F.; Pereira, S. Y.

2014-12-01

High-Voltage Direct Current (HVDC) transmission systems are composed of a bipole transmission line with a converter substation at each end. Each substation may be equipped with a HVDC ground electrode, which is a wide area (up to 1 km Ø) and deep (from 3 to 100m) electrical grounding. When in normal operation, the ground electrode will dissipate in the soil the unbalance of the bipole (~1.5% of the rated current). When in monopolar operation with ground return, the HVDC electrode will inject in the soil the nominal pole continuous current, of about 2000 to 3000 Amperes, continuously for a period up to a few hours. HVDC ground electrodes site selection is a work based on extensive geophysical and geological surveys, in order to attend the desired design requirements established for the electrodes, considering both its operational conditions (maximum soil temperature, working life, local soil voltage gradients etc.) and the interference effects on the installations located up to 50 km away. This poster presents the geophysical investigations conducted primarily for the electrodes site selection, and subsequently for the development of the crust resistivity model, which will be used for the interference studies. A preliminary site selection is conducted, based on general geographical and geological criteria. Subsequently, the geology of each chosen area is surveyed in detail, by means of electromagnetic/electrical geophysical techniques, such as magnetotelluric (deep), TDEM (near-surface) and electroresistivity (shallow). Other complementary geologic and geotechnical surveys are conducted, such as wells drilling (for geotechnical characterization, measurement of the water table depth and water flow, and electromagnetic profiling), and soil and water sampling (for measurement of thermal parameters and evaluation of electrosmosis risk). The site evaluation is a dynamic process along the surveys, and some sites will be discarded. For the two or three final sites, the inversion of the combined deep, near-surface and shallow apparent resistivity curves, results in the layered crust resistivity models. These models will allow for the preliminary interference studies, that will result on the selection of the final electrode site (one for each converter substation).

Theory of plasma contactors in ground-based experiments and low Earth orbit

NASA Technical Reports Server (NTRS)

Gerver, M. J.; Hastings, Daniel E.; Oberhardt, M. R.

1990-01-01

Previous theoretical work on plasma contactors as current collectors has fallen into two categories: collisionless double layer theory (describing space charge limited contactor clouds) and collisional quasineutral theory. Ground based experiments at low current are well explained by double layer theory, but this theory does not scale well to power generation by electrodynamic tethers in space, since very high anode potentials are needed to draw a substantial ambient electron current across the magnetic field in the absence of collisions (or effective collisions due to turbulence). Isotropic quasineutral models of contactor clouds, extending over a region where the effective collision frequency upsilon sub e exceeds the electron cyclotron frequency omega sub ce, have low anode potentials, but would collect very little ambient electron current, much less than the emitted ion current. A new model is presented, for an anisotropic contactor cloud oriented along the magnetic field, with upsilon sub e less than omega sub ce. The electron motion along the magnetic field is nearly collisionless, forming double layers in that direction, while across the magnetic field the electrons diffuse collisionally and the potential profile is determined by quasineutrality. Using a simplified expression for upsilon sub e due to ion acoustic turbulence, an analytic solution has been found for this model, which should be applicable to current collection in space. The anode potential is low and the collected ambient electron current can be several times the emitted ion current.

Effect of Ground Layer Patterns with Slits on Conducted Noise Currents from Printed Circuit Board

NASA Astrophysics Data System (ADS)

Maeno, Tsuyoshi; Unou, Takanori; Ichikawa, Kouji; Fujiwara, Osamu

Electromagnetic disturbances for vehicle-mounted radios can be caused by conducted noise currents that flows out from electronic equipment for vehicles to wire-harnesses. In this paper, for reducing the conducted noise currents from electronic equipment for vehicles, we made a simulation and experiment on how ground patterns affect the noise currents from three-layer printed circuit boards (PCBs) with slit-types and plane-type ground patterns. As a result, we could confirm that slits on a ground pattern allow conducted noise currents to flow out from PCBs to wire-harnesses. For the PCBs with plane-type ground and one of three slit-type patterns, on the other hand, both the simulation and examination showed that resonance phenomena occur at unexpected low-frequencies. A circuit analysis revealed that the above phenomena can be caused by the imbalance of a bridge circuit consisting of the trace circuits on the PCB.

Reagent removal of manganese from ground water

NASA Astrophysics Data System (ADS)

Brayalovsky, G.; Migalaty, E.; Naschetnikova, O.

2017-06-01

The study is aimed at the technology development of treating drinking water from ground waters with high manganese content and oxidizability. Current technologies, physical/chemical mechanisms and factors affecting in ground treatment efficiency are reviewed. Research has been conducted on manganese compound removal from ground waters with high manganese content (5 ppm) and oxidizability. The studies were carried out on granular sorbent industrial ODM-2F filters (0.7-1.5 mm fraction). It was determined that conventional reagent oxidization technologies followed by filtration do not allow us to obtain the manganese content below 0.1 ppm when treating ground waters with high oxidizability. The innovative oxidation-based manganese removal technology with continuous introduction of reaction catalytic agent is suggested. This technology is effective in alkalization up to pH 8.8-9. Potassium permanganate was used as a catalytic agent, sodium hypochlorite was an oxidizer and cauistic soda served an alkalifying agent.

The evolution of discharge current and channel radius in cloud-to-ground lightning return stroke process

NASA Astrophysics Data System (ADS)

Fan, Tingting; Yuan, Ping; Wang, Xuejuan; Cen, Jianyong; Chang, Xuan; Zhao, Yanyan

2017-09-01

The spectra of two negative cloud-to-ground lightning discharge processes with multi-return strokes are obtained by a slit-less high-speed spectrograph, which the temporal resolution is 110 μs. Combined with the synchronous electrical observation data and theoretical calculation, the physical characteristics during return strokes process are analysed. A positive correlation between discharge current and intensity of ionic lines in the spectra is verified, and based on this feature, the current evolution characteristics during four return strokes are investigated. The results show that the time from peak current to the half-peak value estimated by multi point-fitting is about 101 μs-139 μs. The Joule heat in per unit length of four return strokes channel is in the order of 105J/m-106 J/m. The radius of arc discharge channel is positively related to the discharge current, and the more intense the current is, the greater the radius of channel is. Furthermore, the evolution for radius of arc core channel in the process of return stroke is consistent with the change trend of discharge current after the peak value. Compared with the decay of the current, the temperature decreases more slowly.

Observations in the 1.3 and 1.5 THz atmospheric windows with the Receiver Lab Telescope

NASA Technical Reports Server (NTRS)

Marrone, Daniel P.; Blundell, Raymond; Tong, Edward; Paine, Scott N.; Loudkov, Denis; Kawamura, Jonathan H.; Luhr, Daniel; Barrientos, Claudio

2005-01-01

The Receiver Lab Telescope (RLT) is a ground-based terahertz telescope; it is currently the only instrument producing astronmical data between 1 and 2 THz. We report on our first measurements o the high CO transitions, which represent the highest frequency detection ever made from the ground. We also present initial observations of {N II} and discuss the implications of this non-detection for the standard estimates of the strength of this line.

Frontal Polymerization in Microgravity Summary of Research

NASA Technical Reports Server (NTRS)

Pojman, John A.

2002-01-01

The project began with frontal polymerization (FP). We studied many aspects of FP on the ground and performed two successful weeks of flying on the KC-135. The project evolved into the current flight investigation, Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS), as we recognized that an essential question could best be studied using a non-frontal approach. We present detailed results from our ground-based work on FP, KC-135 results and the background, justification and numerical work for the TIPMPS project.

Using long-term ARM observations to evaluate Arctic mixed-phased cloud representation in the GISS ModelE GCM

NASA Astrophysics Data System (ADS)

Lamer, K.; Fridlind, A. M.; Luke, E. P.; Tselioudis, G.; Ackerman, A. S.; Kollias, P.; Clothiaux, E. E.

2016-12-01

The presence of supercooled liquid in clouds affects surface radiative and hydrological budgets, especially at high latitudes. Capturing these effects is crucial to properly quantifying climate sensitivity. Currently, a number of CGMs disagree on the distribution of cloud phase. Adding to the challenge is a general lack of observations on the continuum of clouds, from high to low-level and from warm to cold. In the current study, continuous observations from 2011 to 2014 are used to evaluate all clouds produced by the GISS ModelE GCM over the ARM North Slope of Alaska site. The International Satellite Cloud Climatology Project (ISCCP) Global Weather State (GWS) approach reveals that fair-weather (GWS 7, 32% occurrence rate), as well as mid-level storm related (GWS 5, 28%) and polar (GWS 4, 14%) clouds, dominate the large-scale cloud patterns at this high latitude site. At higher spatial and temporal resolutions, ground-based cloud radar observations reveal a majority of single layer cloud vertical structures (CVS). While clear sky and low-level clouds dominate (each with 30% occurrence rate) a fair amount of shallow ( 10%) to deep ( 5%) convection are observed. Cloud radar Doppler spectra are used along with depolarization lidar observations in a neural network approach to detect the presence, layering and inhomogeneity of supercooled liquid layers. Preliminary analyses indicate that most of the low-level clouds sampled contain one or more supercooled liquid layers. Furthermore, the relationship between CVS and the presence of supercooled liquid is established, as is the relationship between the presence of supercool liquid and precipitation susceptibility. Two approaches are explored to bridge the gap between large footprint GCM simulations and high-resolution ground-based observations. The first approach consists of comparing model output and ground-based observations that exhibit the same column CVS type (i.e. same cloud depth, height and layering). Alternatively, the second approach consists of comparing model output and ground-based observations that exhibit the same large-scale GWS type (i.e. same cloud top pressure and optical depth patterns) where ground-based observations are associated to large-scale GWS every 3 hours using the closest satellite overpass.

Calculation of ground vibration spectra from heavy military vehicles

NASA Astrophysics Data System (ADS)

Krylov, V. V.; Pickup, S.; McNuff, J.

2010-07-01

The demand for reliable autonomous systems capable to detect and identify heavy military vehicles becomes an important issue for UN peacekeeping forces in the current delicate political climate. A promising method of detection and identification is the one using the information extracted from ground vibration spectra generated by heavy military vehicles, often termed as their seismic signatures. This paper presents the results of the theoretical investigation of ground vibration spectra generated by heavy military vehicles, such as tanks and armed personnel carriers. A simple quarter car model is considered to identify the resulting dynamic forces applied from a vehicle to the ground. Then the obtained analytical expressions for vehicle dynamic forces are used for calculations of generated ground vibrations, predominantly Rayleigh surface waves, using Green's function method. A comparison of the obtained theoretical results with the published experimental data shows that analytical techniques based on the simplified quarter car vehicle model are capable of producing ground vibration spectra of heavy military vehicles that reproduce basic properties of experimental spectra.

Comparison of DMSP and SECS region-1 and region-2 ionospheric current boundary

NASA Astrophysics Data System (ADS)

Weygand, J. M.; Wing, S.

2016-06-01

The region-1 and region-2 boundary has traditionally been identified using data from a single spacecraft crossing the auroral region and measuring the large scale changes in the cross track magnetic field. With data from the AUTUMN, CANMOS, CARISMA, GIMA, DTU MGS, MACCS, McMAC, STEP, THEMIS, and USGS ground magnetometer arrays we applied a state-of-art technique based on spherical elementary current system (SECS) method developed by Amm and Viljanen (1999) in order to calculate maps of region-1 and region-2 current system over the North American and Greenland auroral region. Spherical elementary current (SEC) amplitude (proxy for vertical currents) maps can be inferred at 10 s temporal resolution, ~1.5° geographic latitude (Glat), and 3.5° geographic longitude (Glon) spatial resolution. We compare the location of the region-1 and region-2 boundary obtained by the DMSP spacecraft with the region-1 and region-2 boundary observed in the SEC current amplitudes. We find that the boundaries typically agree within 0.2°±1.3°. These results indicate that the location of the region-1 and region-2 boundary can reasonably be determined from ground magnetometer data. The SECS maps represent a value-added product from the magnetometer database and can be used for contextual interpretation in conjunction with other missions as well as help with our understanding of magnetosphere-ionosphere coupling mechanisms using the ground arrays and the magnetospheric spacecraft data.

Comparison of DMSP and SECS region-1 and region-2 ionospheric current boundary✩

PubMed Central

Weygand, J.M.; Wing, S.

2017-01-01

The region-1 and region-2 boundary has traditionally been identified using data from a single spacecraft crossing the auroral region and measuring the large scale changes in the cross track magnetic field. With data from the AUTUMN, CANMOS, CARISMA, GIMA, DTU MGS, MACCS, McMAC, STEP, THEMIS, and USGS ground magnetometer arrays we applied a state-of-art technique based on spherical elementary current system (SECS) method developed by Amm and Viljanen (1999) in order to calculate maps of region-1 and region-2 current system over the North American and Greenland auroral region. Spherical elementary current (SEC) amplitude (proxy for vertical currents) maps can be inferred at 10 s temporal resolution, ~1.5° geographic latitude (Glat), and 3.5° geographic longitude (Glon) spatial resolution. We compare the location of the region-1 and region-2 boundary obtained by the DMSP spacecraft with the region-1 and region-2 boundary observed in the SEC current amplitudes. We find that the boundaries typically agree within 0.2° ± 1.3°. These results indicate that the location of the region-1 and region-2 boundary can reasonably be determined from ground magnetometer data. The SECS maps represent a value-added product from the magnetometer database and can be used for contextual interpretation in conjunction with other missions as well as help with our understanding of magnetosphere-ionosphere coupling mechanisms using the ground arrays and the magnetospheric spacecraft data. PMID:29056861

Comparison of DMSP and SECS region-1 and region-2 ionospheric current boundary.

PubMed

Weygand, J M; Wing, S

2016-06-01

The region-1 and region-2 boundary has traditionally been identified using data from a single spacecraft crossing the auroral region and measuring the large scale changes in the cross track magnetic field. With data from the AUTUMN, CANMOS, CARISMA, GIMA, DTU MGS, MACCS, McMAC, STEP, THEMIS, and USGS ground magnetometer arrays we applied a state-of-art technique based on spherical elementary current system (SECS) method developed by Amm and Viljanen (1999) in order to calculate maps of region-1 and region-2 current system over the North American and Greenland auroral region. Spherical elementary current (SEC) amplitude (proxy for vertical currents) maps can be inferred at 10 s temporal resolution, ~1.5° geographic latitude (Glat), and 3.5° geographic longitude (Glon) spatial resolution. We compare the location of the region-1 and region-2 boundary obtained by the DMSP spacecraft with the region-1 and region-2 boundary observed in the SEC current amplitudes. We find that the boundaries typically agree within 0.2° ± 1.3°. These results indicate that the location of the region-1 and region-2 boundary can reasonably be determined from ground magnetometer data. The SECS maps represent a value-added product from the magnetometer database and can be used for contextual interpretation in conjunction with other missions as well as help with our understanding of magnetosphere-ionosphere coupling mechanisms using the ground arrays and the magnetospheric spacecraft data.

Global change and the distributional dynamics of migratory bird populations wintering in Central America.

PubMed

La Sorte, Frank A; Fink, Daniel; Blancher, Peter J; Rodewald, Amanda D; Ruiz-Gutierrez, Viviana; Rosenberg, Kenneth V; Hochachka, Wesley M; Verburg, Peter H; Kelling, Steve

2017-12-01

Understanding the susceptibility of highly mobile taxa such as migratory birds to global change requires information on geographic patterns of occurrence across the annual cycle. Neotropical migrants that breed in North America and winter in Central America occur in high concentrations on their non-breeding grounds where they spend the majority of the year and where habitat loss has been associated with population declines. Here, we use eBird data to model weekly patterns of abundance and occurrence for 21 forest passerine species that winter in Central America. We estimate species' distributional dynamics across the annual cycle, which we use to determine how species are currently associated with public protected areas and projected changes in climate and land-use. The effects of global change on the non-breeding grounds is characterized by decreasing precipitation, especially during the summer, and the conversion of forest to cropland, grassland, or peri-urban. The effects of global change on the breeding grounds are characterized by increasing winter precipitation, higher temperatures, and the conversion of forest to peri-urban. During spring and autumn migration, species are projected to encounter higher temperatures, forests that have been converted to peri-urban, and increased precipitation during spring migration. Based on current distributional dynamics, susceptibility to global change is characterized by the loss of forested habitats on the non-breeding grounds, warming temperatures during migration and on the breeding grounds, and declining summer rainfall on the non-breeding grounds. Public protected areas with low and medium protection status are more prevalent on the non-breeding grounds, suggesting that management opportunities currently exist to mitigate near-term non-breeding habitat losses. These efforts would affect more individuals of more species during a longer period of the annual cycle, which may create additional opportunities for species to respond to changes in habitat or phenology that are likely to develop under climate change. © 2017 John Wiley & Sons Ltd.

Ground Motion Prediction Trends For Eastern North America Based on the Next Generation Attenuation East Ground Motion Database

NASA Astrophysics Data System (ADS)

Cramer, C. H.; Kutliroff, J.; Dangkua, D.

2010-12-01

A five-year Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), has begun at the Pacific Earthquake Engineering Research (PEER) Center funded by the Nuclear Regulatory Commission (NRC), the U.S. Geological Survey (USGS), the Electric Power Research Institute (EPRI), and the Department of Energy (DOE). The initial effort focused on database design and collection of appropriate M>4 ENA broadband and accelerograph records to populate the database. Ongoing work has focused on adding records from smaller ENA earthquakes and from other SCRs such as Europe, Australia, and India. Currently, over 6500 horizontal and vertical component records from 60 ENA earthquakes have been collected and prepared (instrument response removed, filtering to acceptable-signal band, determining peak and spectral parameter values, quality assurance, etc.) for the database. Geologic Survey of Canada (GSC) strong motion recordings, previously not available, have also been added to the NGA East database. The additional earthquakes increase the number of ground motion recordings in the 10 - 100 km range, particularly from the 2008 M5.2 Mt. Carmel, IL event, and the 2005 M4.7 Riviere du Loup and 2010 M5.0 Val des Bois earthquakes in Quebec, Canada. The goal is to complete the ENA database and make it available in 2011 followed by a SCR database in 2012. Comparisons of ground motion observations from four recent M5 ENA earthquakes with current ENA ground motion prediction equations (GMPEs) suggest that current GMPEs, as a group, reasonably agree with M5 observations at short periods, particularly at distances less than 200 km. However, at one second, current GMPEs over predict M5 ground motion observations. The 2001 M7.6 Bhuj, India, earthquake provides some constraint at large magnitudes, as geology and regional attenuation is analogous to ENA. Cramer and Kumar, 2003, have shown that ENA GMPE’s generally agree with the Bhuj dataset within 300 km at short and long periods. But the Bhuj earthquake does not exhibit the intermediate-period spectral sag (Atkinson, 1993) of larger ENA earthquakes and thus the Bhuj ground motions may be larger than what could be expected at one second for M7s in ENA.

Space Mission Human Reliability Analysis (HRA) Project

NASA Technical Reports Server (NTRS)

Boyer, Roger

2014-01-01

The purpose of the Space Mission Human Reliability Analysis (HRA) Project is to extend current ground-based HRA risk prediction techniques to a long-duration, space-based tool. Ground-based HRA methodology has been shown to be a reasonable tool for short-duration space missions, such as Space Shuttle and lunar fly-bys. However, longer-duration deep-space missions, such as asteroid and Mars missions, will require the crew to be in space for as long as 400 to 900 day missions with periods of extended autonomy and self-sufficiency. Current indications show higher risk due to fatigue, physiological effects due to extended low gravity environments, and others, may impact HRA predictions. For this project, Safety & Mission Assurance (S&MA) will work with Human Health & Performance (HH&P) to establish what is currently used to assess human reliabiilty for human space programs, identify human performance factors that may be sensitive to long duration space flight, collect available historical data, and update current tools to account for performance shaping factors believed to be important to such missions. This effort will also contribute data to the Human Performance Data Repository and influence the Space Human Factors Engineering research risks and gaps (part of the HRP Program). An accurate risk predictor mitigates Loss of Crew (LOC) and Loss of Mission (LOM).The end result will be an updated HRA model that can effectively predict risk on long-duration missions.

Potential Chemical Effects of Changes in the Source of Water Supply for the Albuquerque Bernalillo County Water Utility Authority

USGS Publications Warehouse

Bexfield, Laura M.; Anderholm, Scott K.

2008-01-01

Chemical modeling was used by the U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (henceforth, Authority), to gain insight into the potential chemical effects that could occur in the Authority's water distribution system as a result of changing the source of water used for municipal and industrial supply from ground water to surface water, or to some mixture of the two sources. From historical data, representative samples of ground-water and surface-water chemistry were selected for modeling under a range of environmental conditions anticipated to be present in the distribution system. Mineral phases calculated to have the potential to precipitate from ground water were compared with the compositions of precipitate samples collected from the current water distribution system and with mineral phases calculated to have the potential to precipitate from surface water and ground-water/surface-water mixtures. Several minerals that were calculated to have the potential to precipitate from ground water in the current distribution system were identified in precipitate samples from pipes, reservoirs, and water heaters. These minerals were the calcium carbonates aragonite and calcite, and the iron oxides/hydroxides goethite, hematite, and lepidocrocite. Several other minerals that were indicated by modeling to have the potential to precipitate were not found in precipitate samples. For most of these minerals, either the kinetics of formation were known to be unfavorable under conditions present in the distribution system or the minerals typically are not formed through direct precipitation from aqueous solutions. The minerals with potential to precipitate as simulated for surface-water samples and ground-water/surface-water mixtures were quite similar to the minerals with potential to precipitate from ground-water samples. Based on the modeling results along with kinetic considerations, minerals that appear most likely to either dissolve or newly precipitate when surface water or ground-water/surface-water mixtures are delivered through the Authority's current distribution system are carbonates (particularly aragonite and calcite). Other types of minerals having the potential to dissolve or newly precipitate under conditions present throughout most of the distribution system include a form of silica, an aluminum hyroxide (gibbsite or diaspore), or the Fe-containing mineral Fe3(OH)8. Dissolution of most of these minerals (except perhaps the Fe-containing minerals) is not likely to substantially affect trace-element concentrations or aesthetic characteristics of delivered water, except perhaps hardness. Precipitation of these minerals would probably be of concern only if the quantities of material involved were large enough to clog pipes or fixtures. The mineral Fe3(OH)8 was not found in the current distribution system. Some Fe-containing minerals that were identified in the distribution system were associated with relatively high contents of selected elements, including As, Cr, Cu, Mn, Pb, and Zn. However, these Fe-containing minerals were not identified as minerals likely to dissolve when the source of water was changed from ground water to surface water or a ground-water/surface-water mixture. Based on the modeled potential for calcite precipitation and additional calculations of corrosion indices ground water, surface water, and ground-water/surface-water mixtures are not likely to differ greatly in corrosion potential. In particular, surface water and ground-water/surface-water mixtures do not appear likely to dissolve large quantities of existing calcite and expose metal surfaces in the distribution system to substantially increased corrosion. Instead, modeling calculations indicate that somewhat larger masses of material would tend to precipitate from surface water or ground-water/surface-water mixtures compared to ground water alone.

End-of-Life Care and Dying: Issues Raised by Staff Supporting Older People with Intellectual Disability in Community Living Services

ERIC Educational Resources Information Center

Wiese, Michele; Stancliffe, Roger J.; Balandin, Susan; Howarth, Glennys; Dew, Angela

2012-01-01

Background: The aim of this study was to explore the current status of end-of-life care and dying of people with intellectual disability based on the experiences of staff in community living services. Materials and Methods: Focus groups and individual interviews were conducted, guided by grounded theory methodology. Results: The current status of…

A method for the retrieval of atomic oxygen density and temperature profiles from ground-based measurements of the O(+)(2D-2P) 7320 A twilight airglow

NASA Technical Reports Server (NTRS)

Fennelly, J. A.; Torr, D. G.; Richards, P. G.; Torr, M. R.; Sharp, W. E.

1991-01-01

This paper describes a technique for extracting thermospheric profiles of the atomic-oxygen density and temperature, using ground-based measurements of the O(+)(2D-2P) doublet at 7320 and 7330 A in the twilight airglow. In this method, a local photochemical model is used to calculate the 7320-A intensity; the method also utilizes an iterative inversion procedure based on the Levenberg-Marquardt method described by Press et al. (1986). The results demonstrate that, if the measurements are only limited by errors due to Poisson noise, the altitude profiles of neutral temperature and atomic oxygen concentration can be determined accurately using currently available spectrometers.

Risk of Performance Decrements and Adverse Health Outcomes Resulting from Sleep Loss, Circadian Desynchronization, and Work Overload

NASA Technical Reports Server (NTRS)

Flynn-Evans, Erin; Gregory, Kevin; Arsintescu, Lucia; Whitmire, Alexandra

2016-01-01

Sleep loss, circadian desynchronization, and work overload occur to some extent for ground and flight crews, prior to and during spaceflight missions. Ground evidence indicates that such risk factors may lead to performance decrements and adverse health outcomes, which could potentially compromise mission objectives. Efforts are needed to identify the environmental and mission conditions that interfere with sleep and circadian alignment, as well as individual differences in vulnerability and resiliency to sleep loss and circadian desynchronization. Specifically, this report highlights a collection of new evidence to better characterize the risk and reveals new gaps in this risk as follows: Sleep loss is apparent during spaceflight. Astronauts consistently average less sleep during spaceflight relative to on the ground. The causes of this sleep loss remain unknown, however ground-based evidence suggests that the sleep duration of astronauts is likely to lead to performance impairment and short and long-term health consequences. Further research is needed in this area in order to develop screening tools to assess individual astronaut sleep need in order to quantify the magnitude of sleep loss during spaceflight; current and planned efforts in BHP's research portfolio address this need. In addition, it is still unclear whether the conditions of spaceflight environment lead to sleep loss or whether other factors, such as work overload lead to the reduced sleep duration. Future data mining efforts and continued data collection on the ISS will help to further characterize factors contributing to sleep loss. Sleep inertia has not been evaluated during spaceflight. Ground-based studies confirm that it takes two to four hours to achieve optimal performance after waking from a sleep episode. Sleep inertia has been associated with increased accidents and reduced performance in operational environments. Sleep inertia poses considerable risk during spaceflight when emergency situations necessitate that crewmembers wake from sleep and make quick decisions. A recently completed BHP investigation assesses the effects of sleep inertia upon abrupt awakening, with and without hypnotics currently used in spaceflight; results from this investigation will help to inform strategies relative to sleep inertia effects on performance. Circadian desynchrony has been observed during spaceflight. Circadian desynchrony during spaceflight develops due to schedule constraints requiring non-24 operations or 'slam-shifts' and due to insufficient or mis-timed light exposure. In addition, circadian misalignment has been associated with reduced sleep duration and increased medication use. In ground-based studies, circadian desynchrony has been associated with significant performance impairment and increased risk of accidents when operations coincide with the circadian nadir. There is a great deal of information available on how to manage circadian misalignment, however, there are currently no easily collected biomarkers that can be used during spaceflight to determine circadian phase. Current research efforts are addressing this gap. Work overload has been documented during current spaceflight operations. NASA has established work hour guidelines that limit shift duration, however, schedule creep, where duty requirements necessitate working beyond scheduled work hours, has been reported. This observation warrants the documentation of actual work hours in order to improve planning and in order to ensure that astronauts receive adequate down time. In addition to concerns about work overload, ground based evidence suggests that work underload may be a concern during deep space missions, where torpor may develop and physically demanding workload will be exchanged for monitoring of autonomous systems. Given that increased automation is anticipated for exploration vehicles, fatigue effects in the context of such systems needs to be further understood. Performance metrics are needed to evaluate fitness-for-duty during spaceflight. Although ground-based evidence supports the notion that sleep loss, circadian desynchronization and work overload lead to performance impairment, inconsistency in the measures used to evaluate performance during spaceflight make it difficult to evaluate the magnitude of performance impairment during spaceflight. Work is underway to standardize measures of performance evaluation during spaceflight. Once established, such performance indicators need to be correlated with operational performance. Individual differences in sleep need and circadian preference, phase shifting ability and period have been documented in ground-based studies. Individual differences in response to sleep loss and circadian misalignment have also been documented and are presumed to be associated with genetic polymorphisms. No studies have systematically reported individual differences in sleep or circadian-related outcomes during spaceflight. More work is needed in this area in order to identify genetic or phenotypic biomarkers that predict resilience or vulnerability to sleep loss in order to personalize countermeasure strategies and mitigate performance impairment during spaceflight. Two laboratory and field investigations specific to this topic are currently ongoing; additional efforts, including an effort to mine existing biological data from spaceflight relative to sleep and circadian outcomes, are planned. Sex differences in sleep need and circadian period and phase have been reported in ground-based studies. The impact of these sex differences on performance is unclear. Sex differences in sleep need and circadian rhythms have not been systematically studied during spaceflight, presumably due to the small number of women that have flown in space. More research is needed in this area to evaluate whether any of the observed sex differences in physiology lead to altered performance in spaceflight and on the ground.

Estimating ionospheric currents by inversion from ground-based geomagnetic data and calculating geoelectric fields for studies of geomagnetically induced currents

NASA Astrophysics Data System (ADS)

de Villiers, J. S.; Pirjola, R. J.; Cilliers, P. J.

2016-09-01

This research focuses on the inversion of geomagnetic variation field measurements to obtain the source currents in the ionosphere and magnetosphere, and to determine the geoelectric fields at the Earth's surface. During geomagnetic storms, the geoelectric fields create geomagnetically induced currents (GIC) in power networks. These GIC may disturb the operation of power systems, cause damage to power transformers, and even result in power blackouts. In this model, line currents running east-west along given latitudes are postulated to exist at a certain height above the Earth's surface. This physical arrangement results in the fields on the ground being composed of a zero magnetic east component and a nonzero electric east component. The line current parameters are estimated by inverting Fourier integrals (over wavenumber) of elementary geomagnetic fields using the Levenberg-Marquardt technique. The output parameters of the model are the ionospheric current strength and the geoelectric east component at the Earth's surface. A conductivity profile of the Earth is adapted from a shallow layered-Earth model for one observatory, together with a deep-layer model derived from satellite observations. This profile is used to obtain the ground surface impedance and therefore the reflection coefficient in the integrals. The inputs for the model are a spectrum of the geomagnetic data for 31 May 2013. The output parameters of the model are spectrums of the ionospheric current strength and of the surface geoelectric field. The inverse Fourier transforms of these spectra provide the time variations on the same day. The geoelectric field data can be used as a proxy for GIC in the prediction of GIC for power utilities. The current strength data can assist in the interpretation of upstream solar wind behaviour.

Fast Coherent Differential Imaging for Exoplanet Imaging

NASA Astrophysics Data System (ADS)

Gerard, Benjamin; Marois, Christian; Galicher, Raphael; Veran, Jean-Pierre; Macintosh, B.; Guyon, O.; Lozi, J.; Pathak, P.; Sahoo, A.

2018-06-01

Direct detection and detailed characterization of exoplanets using extreme adaptive optics (ExAO) is a key science goal of future extremely large telescopes and space observatories. However, quasi-static wavefront errors will limit the sensitivity of this endeavor. Additional limitations for ground-based telescopes arise from residual AO-corrected atmospheric wavefront errors, generating short-lived aberrations that will average into a halo over a long exposure, also limiting the sensitivity of exoplanet detection. We develop the framework for a solution to both of these problems using the self-coherent camera (SCC), to be applied to ground-based telescopes, called Fast Atmospheric SCC Technique (FAST). Simulations show that for typical ExAO targets the FAST approach can reach ~100 times better in raw contrast than what is currently achieved with ExAO instruments if we extrapolate for an hour of observing time, illustrating that the sensitivity improvement from this method could play an essential role in the future ground-based detection and characterization of lower mass/colder exoplanets.

Potential use of ground-based sensor technologies for weed detection.

PubMed

Peteinatos, Gerassimos G; Weis, Martin; Andújar, Dionisio; Rueda Ayala, Victor; Gerhards, Roland

2014-02-01

Site-specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground-based or near-range sensors in combination with decision rules and precise application technologies. Near-range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe-ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given. © 2013 Society of Chemical Industry.

Functional Allocation for Ground-Based Automated Separation Assurance in NextGen

NASA Technical Reports Server (NTRS)

Prevot, Thomas; Mercer, Joey; Martin, Lynne; Homola, Jeffrey; Cabrall, Christopher; Brasil, Connie

2010-01-01

As part of an ongoing research effort into functional allocation in a NextGen environment, a controller-in-the-loop study on ground-based automated separation assurance was conducted at NASA Ames' Airspace Operations Laboratory in February 2010. Participants included six FAA front line managers, who are currently certified professional controllers and four recently retired controllers. Traffic scenarios were 15 and 30 minutes long where controllers interacted with advanced technologies for ground-based separation assurance, weather avoidance, and arrival metering. The automation managed the separation by resolving conflicts automatically and involved controllers only by exception, e.g., when the automated resolution would have been outside preset limits. Results from data analyses show that workload was low despite high levels of traffic, Operational Errors did occur but were closely tied to local complexity, and safety acceptability ratings varied with traffic levels. Positive feedback was elicited for the overall concept with discussion on the proper allocation of functions and trust in automation.

Predicting ground-water movement in large mine spoil areas in the Appalachian Plateau

USGS Publications Warehouse

Wunsch, D.R.; Dinger, J.S.; Graham, C.D.R.

1999-01-01

Spoil created by surface mining can accumulate large quantities of ground-water, which can create geotechnical or regulatory problems, as well as flood active mine pits. A current study at a large (4.1 km2), thick, (up to 90 m) spoil body in eastern Kentucky reveals important factors that control the storage and movement of water. Ground-water recharge occurs along the periphery of the spoil body where surface-water drainage is blocked, as well as from infiltration along the spoil-bedrock contact, recharge from adjacent bedrock, and to a minor extent, through macropores at the spoil's surface. Based on an average saturated thickness of 6.4 m for all spoil wells, and assuming an estimated porosity of 20%, approximately 5.2 x 106 m3 of water is stored within the existing 4.1 km2 of reclaimed spoil. A conceptual model of ground-water flow, based on data from monitoring wells, dye-tracing data, discharge from springs and ponds, hydraulic gradients, chemical data, field reconnaissance, and aerial photographs indicate that three distinct but interconnected saturated zones have been established: one in the spoil's interior, and others in the valley fills that surround the main spoil body at lower elevations. Ground-water movement is sluggish in the spoil's interior, but moves quickly through the valley fills. The conceptual model shows that a prediction of ground-water occurrence, movement, and quality can be made for active or abandoned spoil areas if all or some of the following data are available: structural contour of the base of the lowest coal seam being mined, pre-mining topography, documentation of mining methods employed throughout the mine, overburden characteristics, and aerial photographs of mine progression.Spoil created by surface mining can accumulate large quantities of ground-water, which can create geotechnical or regulatory problems, as well as flood active mine pits. A current study at a large (4.1 km2), thick, (up to 90 m) spoil body in eastern Kentucky reveals important factors that control the storage and movement of water. Ground-water recharge occurs along the periphery of the spoil body where surface-water drainage is blocked, as well as from infiltration along the spoil-bedrock contact, recharge from adjacent bedrock, and to a minor extent, through macropores at the spoil's surface. Based on an average saturated thickness of 6.4 m for all spoil wells, and assuming an estimated porosity of 20%, approximately 5.2 ?? 106 m3 of water is stored within the existing 4.1 km2 of reclaimed spoil. A conceptual model of ground-water flow, based on data from monitoring wells, dye-tracing data, discharge from springs and ponds, hydraulic gradients, chemical data, field reconnaissance, and aerial photographs indicate that three distinct but interconnected saturated zones have been established: one in the spoil's interior, and others in the valley fills that surround the main spoil body at lower elevations. Ground-water movement is sluggish in the spoil's interior, but moves quickly through the valley fills. The conceptual model shows that a prediction of ground-water occurrence, movement, and quality can be made for active or abandoned spoil areas if all or some of the following data are available: structural contour of the base of the lowest coal seam being mined, pre-mining topography, documentation of mining methods employed throughout the mine, overburden characteristics, and aerial photographs of mine progression.

Portable traceability solution for ground-based calibration of optical instruments

NASA Astrophysics Data System (ADS)

El Gawhary, Omar; van Veghel, Marijn; Kenter, Pepijn; van der Leden, Natasja; Dekker, Paul; Revtova, Elena; Heemskerk, Maurice; Trarbach, André; Vink, Ramon; Doyle, Dominic

2017-11-01

We present a portable traceability solution for the ground-based optical calibration of earth observation (EO) instruments. Currently, traceability for this type of calibration is typically based on spectral irradiance sources (e.g. FEL lamps) calibrated at a national metrology institute (NMI). Disadvantages of this source-based traceability are the inflexibility in operating conditions of the source, which are limited to the settings used during calibration at the NMI, and the susceptibility to aging, which requires frequent recalibrations, and which cannot be easily checked on-site. The detector-based traceability solution presented in this work uses a portable filter radiometer to calibrate light sources onsite, immediately before and after, or even during instrument calibration. The filter radiometer itself is traceable to the primary standard of radiometry in the Netherlands. We will discuss the design and realization, calibration and performance verification.

Improving INPE'S balloon ground facilities for operation of the protoMIRAX experiment

NASA Astrophysics Data System (ADS)

Mattiello-Francisco, F.; Rinke, E.; Fernandes, J. O.; Cardoso, L.; Cardoso, P.; Braga, J.

2014-10-01

The system requirements for reusing the scientific balloon ground facilities available at INPE were a challenge to the ground system engineers involved in the protoMIRAX X-ray astronomy experiment. A significant effort on software updating was required for the balloon ground station. Considering that protoMIRAX is a pathfinder for the MIRAX satellite mission, a ground infrastructure compatible with INPE's satellite operation approach would be useful and highly recommended to control and monitor the experiment during the balloon flights. This approach will make use of the SATellite Control System (SATCS), a software-based architecture developed at INPE for satellite commanding and monitoring. SATCS complies with particular operational requirements of different satellites by using several customized object-oriented software elements and frameworks. We present the ground solution designed for protoMIRAX operation, the Control and Reception System (CRS). A new server computer, properly configured with Ethernet, has extended the existing ground station facilities with switch, converters and new software (OPS/SERVER) in order to support the available uplink and downlink channels being mapped to TCP/IP gateways required by SATCS. Currently, the CRS development is customizing the SATCS for the kernel functions of protoMIRAX command and telemetry processing. Design-patterns, component-based libraries and metadata are widely used in the SATCS in order to extend the frameworks to address the Packet Utilization Standard (PUS) for ground-balloon communication, in compliance with the services provided by the data handling computer onboard the protoMIRAX balloon.

Magnetosphere-ionosphere coupling during substorm onset

NASA Technical Reports Server (NTRS)

Maynard, N. C.; Burke, W. J.; Erickson, G. M.; Basinka, E. M.; Yahnin, A. G.

1996-01-01

Through the analysis of a combination of CRRES satellite measurements and ground-based measurements, an empirical scenario was developed for the onset of substorms. The process develops from ripples at the inner edge of the plasma sheet associated with dusk to dawn excursions of the electric field, prior to the beginning of dipolarization. The importance of Poynting flux is considered. Substorms develop when significant amounts of energy flow in both directions with the second cycle stronger than the initial cycle. Pseudobreakups occur when the energy flowing in both directions is weak or out of phase. The observations indicate that the dusk to dawn excursions of the cross-tail electric field correlate with changes in currents and particle energies observed by CRRES, and with ultra low frequency wave activity observed on the ground. Magnetic signatures of field aligned current filaments, associated with the substorm current wedge were observed to be initiated by the process.

An Investigation of Widespread Ozone Damage to the Soybean Crop in the Upper Midwest Determined From Ground-Based and Satellite Measurements

NASA Technical Reports Server (NTRS)

Fishman, Jack; Creilson, John K.; Parker, Peter A.; Ainsworth, Elizabeth A.; Vining, G. Geoffrey; Szarka, John; Booker, Fitzgerald L.; Xu, Xiaojing

2010-01-01

Elevated concentrations of ground-level ozone (O3) are frequently measured over farmland regions in many parts of the world. While numerous experimental studies show that O3 can significantly decrease crop productivity, independent verifications of yield losses at current ambient O3 concentrations in rural locations are sparse. In this study, soybean crop yield data during a 5-year period over the Midwest of the United States were combined with ground and satellite O3 measurements to provide evidence that yield losses on the order of 10% could be estimated through the use of a multiple linear regression model. Yield loss trends based on both conventional ground-based instrumentation and satellite-derived tropospheric O3 measurements were statistically significant and were consistent with results obtained from open-top chamber experiments and an open-air experimental facility (SoyFACE, Soybean Free Air Concentration Enrichment) in central Illinois. Our analysis suggests that such losses are a relatively new phenomenon due to the increase in background tropospheric O3 levels over recent decades. Extrapolation of these findings supports previous studies that estimate the global economic loss to the farming community of more than $10 billion annually.

A 2.5D Map-Based Mobile Robot Localization via Cooperation of Aerial and Ground Robots

PubMed Central

Nam, Tae Hyeon; Shim, Jae Hong; Cho, Young Im

2017-01-01

Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM) process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth) sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed. PMID:29186843

A moving target: responding to magnetic and structural disorder in lanthanide- and actinide-based superconductors

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

Bauer, Eric D; Mitchell, Jeremy N; Booth, C H

2009-01-01

The effects of various chemical substitutions and induced lattice disorder in the Ce- and Pu-based 115 superconductors are reviewed, with particular emphasis on results from x-ray absorption fine structure (XAFS) measurements. The competition between spin, charge, and lattice interactions is at the heart of many of the strongly-correlated ground states in materials of current interest, such as in colossal magnetoresistors and high-temperature superconductors. This relationship is particularly strong in the CeTIn{sub 5} and PuTGa{sub 5} series (T = Co, Rh, Ir) of heavy-fermion superconductors. In these systems (figure 1), competition between bulk magnetic and non-magnetic ground states, as well asmore » between superconducting and normal states, are directly related to local properties around the lanthanide or actinide ion, such as the nearest-neighbor bond lengths and the local density of states at the Fermi level. Tiny changes in the latter values can easily tip the balance from one ground state to another. This paper reviews recent work by the authors exploring the relationship between local crystal and electronic structure and ground state magnetic and conducting properties in the Ce- and Pu-based 115 materials.« less

A 2.5D Map-Based Mobile Robot Localization via Cooperation of Aerial and Ground Robots.

PubMed

Nam, Tae Hyeon; Shim, Jae Hong; Cho, Young Im

2017-11-25

Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM) process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth) sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed.

Putting Order into Our Universe: The Concept of "Blended Learning"--A Methodology within the Concept-Based Terminology Framework

ERIC Educational Resources Information Center

Fernandes, Joana; Costa, Rute; Peres, Paula

2016-01-01

This paper aims at discussing the advantages of a methodology design grounded on a concept-based approach to Terminology applied to the most prominent scenario of current Higher Education: "blended learning." Terminology is a discipline that aims at representing, describing and defining specialized knowledge through language, putting…

Automated Ground Umbilical Systems (AGUS) Project

NASA Technical Reports Server (NTRS)

Gosselin, Armand M.

2007-01-01

All space vehicles require ground umbilical systems for servicing. Servicing requirements can include, but are not limited to, electrical power and control, propellant loading and venting, pneumatic system supply, hazard gas detection and purging as well as systems checkout capabilities. Of the various types of umbilicals, all require several common subsystems. These typically include an alignment system, mating and locking system, fluid connectors, electrical connectors and control !checkout systems. These systems have been designed to various levels of detail based on the needs for manual and/or automation requirements. The Automated Ground Umbilical Systems (AGUS) project is a multi-phase initiative to develop design performance requirements and concepts for launch system umbilicals. The automation aspect minimizes operational time and labor in ground umbilical processing while maintaining reliability. This current phase of the project reviews the design, development, testing and operations of ground umbilicals built for the Saturn, Shuttle, X-33 and Atlas V programs. Based on the design and operations lessons learned from these systems, umbilicals can be optimized for specific applications. The product of this study is a document containing details of existing systems and requirements for future automated umbilical systems with emphasis on design-for-operations (DFO).

A large-scale intercomparison of stratospheric vertical distributions of NO2 and BrO retrieved from the SCIAMACHY limb measurements and ground-based twilight observations

NASA Astrophysics Data System (ADS)

Rozanov, Alexei; Hendrick, Francois; Lotz, Wolfhardt; van Roozendael, Michel; Bovensmann, Heinrich; Burrows, John P.

This study is devoted to the intercomparison of NO2 and BrO vertical profiles obtained from the satellite and ground-based measurements. Although, the ground-based observations are performed only at selected locations, they have a great potential to be used for the validation of satellite measurements since continuous long-term measurement series performed with the same instruments are available. Thus, long-term trends in the observed species can be analyzed and intercompared. Previous intercomparisons of the vertical distributions of NO2 and BrO retrieved from SCIAMACHY limb measurements at the University of Bremen and obtained at IASB-BIRA by applying a profiling technique to ground-based zenith-sky DOAS observations have shown a good agreement between the results of completely different measurement techniques. However, only a relatively short time period of one year was analyzed so far which do not allow investigating seasonal variations and trends. Furthermore, some minor discrepancies are still to be analyzed. In the current study, several years datasets obtained at Observatoire de Haute-Provence (OHP) in France and in Harestua in Norway will be compared to the retrievals of SCIAMACHY limb measurements. Seasonal and annual variations will be analyzed and possible reasons for the remaining discrepancies will be discussed.

Effect of Ground Patterns Size on FM-Band Cross-Talks between Two Parallel Signal Traces of Printed Circuit Boards for Vehicles

NASA Astrophysics Data System (ADS)

Iida, Michihira; Maeno, Tsuyoshi; Fujiwara, Osamu

It is well known that electromagnetic disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns containing slits. To suppress the noise currents outflow from PCBs of these kinds, we previously measured noise currents outflow from simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits to reveal that making slits with open ends on the ground patterns in parallel with the traces can reduce the conducted noise currents. In the present study, with FDTD simulation, we investigated reduction effects of ground patterns size on the FM-band cross-talk noise levels between two parallel signal traces, by using four types of simple PCB models having different ground patterns formed in different numbers but containing the same planar dimension slits parallel to the traces, in addition to two types of PCB models with different ground patterns divided into two parts parallel to the traces. As a result, we found that the cross-talk noise currents for the above six types of PCBs decrease by 6.9-8.5dB compared to the PCB which has a plain ground with no slits. From this study, we got the finding that the contributing factor for the above mentioned cross-talk reduction relies on the reduction of mutual inductance between the two parallel traces. In addition, in case of this study, it is interesting to note that the noise currents outflow from PCBs can rather be suppressed when the size of the return ground of each signal trace is small.

A Study to Compare the Failure Rates of Current Space Shuttle Ground Support Equipment with the New Pathfinder Equipment and Investigate the Effect that the Proposed GSE Infrastructure Upgrade Might Have to Reduce GSE Infrastructure Failures

NASA Technical Reports Server (NTRS)

Kennedy, Barbara J.

2004-01-01

The purposes of this study are to compare the current Space Shuttle Ground Support Equipment (GSE) infrastructure with the proposed GSE infrastructure upgrade modification. The methodology will include analyzing the first prototype installation equipment at Launch PAD B called the "Pathfinder". This study will begin by comparing the failure rate of the current components associated with the "Hardware interface module (HIM)" at the Kennedy Space Center to the failure rate of the neW Pathfinder components. Quantitative data will be gathered specifically on HIM components and the PAD B Hypergolic Fuel facility and Hypergolic Oxidizer facility areas which has the upgraded pathfinder equipment installed. The proposed upgrades include utilizing industrial controlled modules, software, and a fiber optic network. The results of this study provide evidence that there is a significant difference in the failure rates of the two studied infrastructure equipment components. There is also evidence that the support staff for each infrastructure system is not equal. A recommendation to continue with future upgrades is based on a significant reduction of failures in the new' installed ground system components.

Substorm Current Wedge Revisited

NASA Astrophysics Data System (ADS)

Kepko, L.; McPherron, R. L.; Amm, O.; Apatenkov, S.; Baumjohann, W.; Birn, J.; Lester, M.; Nakamura, R.; Pulkkinen, T. I.; Sergeev, V.

2015-07-01

Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the substorm current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. While the large-scale picture remains valid, the new details call for revision and an update of the original view. In this paper we briefly review the historical development of the substorm current wedge, review recent in situ and ground-based observations and theoretical work, and discuss the current active research areas. We conclude with a revised, time-dependent picture of the substorm current wedge that follows its evolution from the initial substorm flows through substorm expansion and recovery.

Gravitational wave searches using the DSN (Deep Space Network)

NASA Technical Reports Server (NTRS)

Nelson, S. J.; Armstrong, J. W.

1988-01-01

The Deep Space Network Doppler spacecraft link is currently the only method available for broadband gravitational wave searches in the 0.01 to 0.001 Hz frequency range. The DSN's role in the worldwide search for gravitational waves is described by first summarizing from the literature current theoretical estimates of gravitational wave strengths and time scales from various astrophysical sources. Current and future detection schemes for ground based and space based detectors are then discussed. Past, present, and future planned or proposed gravitational wave experiments using DSN Doppler tracking are described. Lastly, some major technical challenges to improve gravitational wave sensitivities using the DSN are discussed.

Resolution of the discrepancy between Balmer alpha emission rates, the solar Lyman beta flux, and models of geocoronal hydrogen concentration

NASA Technical Reports Server (NTRS)

Levasseur, A.-C.; Meier, R. R.; Tinsley, B. A.

1976-01-01

New satellite Balmer alpha measurements and solar Lyman beta flux and line profile measurements, together with new measurements of the zodiacal light intensity used in correcting both ground and satellite Balmer alpha measurements for the effects of the Fraunhofer line in the zodiacal light, have been used in a reevaluation of the long-standing discrepancy between ground-based Balmer alpha emission rates and other geocoronal hydrogen parameters. The solar Lyman beta line center flux is found to be (4.1 plus or minus 1.3) billion photons per sq cm per sec per angstrom at S(10.7) equals 110 and, together with a current hydrogen model which has 92,000 atoms per cu cm at 650 km for T(inf) equals 950 K, gives good agreement between calculated Balmer alpha emission rates and the ground-based and satellite measurements.

Comparisons of COSMIC and C/NOFS GPS Occultation Ionospheric Scintillation Measurements with Ground-based Radar and VHF Measurements

NASA Astrophysics Data System (ADS)

Ruggiero, F. H.; Groves, K. M.; Straus, P. R.; Caton, R. G.; Starks, M. J.; Tanyi, K. L.; Verlinden, M.

2009-12-01

Ionospheric irregularities are known to cause scintillation of trans-ionospheric radio signals and can affect space-based UHF/VHF communications, causing outages, and degrading GPS accuracy and precision. Current capability for characterizing and predicting ionospheric scintillation utilizes a network of ground-based receivers to detect scintillation and then extrapolate for short-term forecasts. Practical limits on deploying the ground receivers limits the accuracy and spatial coverage one can achieve with this approach. A more global approach is to use a set of space-based satellites equipped with GPS receivers, such as the COSMIC satellite constellation, to measure scintillations observed during so-called occultations with GPS satellites. In this paper the signal-to-noise values of GPS L1 signals received on the COSMIC and C/NOFS satellites for the portions of the occultations that are not affected by the terrestrial atmosphere are examined to help identify areas of ionospheric scintillation. Three years of S4 scintillation index values from COSMIC occultations are compared with near-zenith ground-based VHF S4 scintillation measurements from the AFRL SCIntillation Network Decision Aid (SCINDA) network stations. The data are correlated to ascertain the viability of using space-based scintillation measurements to characterize and predict scintillation to ground-based receivers. Several days of COSMIC and C/NOFS data are compared with each other and the ALTAIR radar located on Kwajalein Atoll, Marshall Islands to examine how occultation geometry affects observed scintillation and also to verify techniques that provide an upper bound on the spatial location of the ionospheric irregularities contributing to scintillations observed in the occultations.

NASA GeneLab Project: Bridging Space Radiation Omics with Ground Studies

NASA Technical Reports Server (NTRS)

Beheshti, Afshin; Miller, Jack; Kidane, Yared H.; Berrios, Daniel; Gebre, Samrawit G.; Costes, Sylvain V.

2018-01-01

Accurate assessment of risk factors for long-term space missions is critical for human space exploration: therefore it is essential to have a detailed understanding of the biological effects on humans living and working in deep space. Ionizing radiation from Galactic Cosmic Rays (GCR) is one of the major risk factors factor that will impact health of astronauts on extended missions outside the protective effects of the Earth's magnetic field. Currently there are gaps in our knowledge of the health risks associated with chronic low dose, low dose rate ionizing radiation, specifically ions associated with high (H) atomic number (Z) and energy (E). The GeneLab project (genelab.nasa.gov) aims to provide a detailed library of Omics datasets associated with biological samples exposed to HZE. The GeneLab Data System (GLDS) currently includes datasets from both spaceflight and ground-based studies, a majority of which involve exposure to ionizing radiation. In addition to detailed information for ground-based studies, we are in the process of adding detailed, curated dosimetry information for spaceflight missions. GeneLab is the first comprehensive Omics database for space related research from which an investigator can generate hypotheses to direct future experiments utilizing both ground and space biological radiation data. In addition to previously acquired data, the GLDS is continually expanding as Omics related data are generated by the space life sciences community. Here we provide a brief summary of space radiation related data available at GeneLab.

Ground-Based Facilities for Simulation of Microgravity: Organism-Specific Recommendations for Their Use, and Recommended Terminology

PubMed Central

Anken, Ralf; Boonstra, Johannes; Braun, Markus; Christianen, Peter C.M.; de Geest, Maarten; Hauslage, Jens; Hilbig, Reinhard; Hill, Richard J.A.; Lebert, Michael; Medina, F. Javier; Vagt, Nicole; Ullrich, Oliver

2013-01-01

Abstract Research in microgravity is indispensable to disclose the impact of gravity on biological processes and organisms. However, research in the near-Earth orbit is severely constrained by the limited number of flight opportunities. Ground-based simulators of microgravity are valuable tools for preparing spaceflight experiments, but they also facilitate stand-alone studies and thus provide additional and cost-efficient platforms for gravitational research. The various microgravity simulators that are frequently used by gravitational biologists are based on different physical principles. This comparative study gives an overview of the most frequently used microgravity simulators and demonstrates their individual capacities and limitations. The range of applicability of the various ground-based microgravity simulators for biological specimens was carefully evaluated by using organisms that have been studied extensively under the conditions of real microgravity in space. In addition, current heterogeneous terminology is discussed critically, and recommendations are given for appropriate selection of adequate simulators and consistent use of nomenclature. Key Words: 2-D clinostat—3-D clinostat—Gravity—Magnetic levitation—Random positioning machine—Simulated microgravity—Space biology. Astrobiology 13, 1–17. PMID:23252378

The Substorm Current Wedge Revisited

NASA Astrophysics Data System (ADS)

Kepko, Larry; McPherron, Robert; Apatenkov, Sergey; Baumjohann, Wolfgang; Birn, Joachim; Lester, Mark; Nakamura, Rumi; Pulkkinen, Tuija; Sergeev, Victor

2015-04-01

Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the substorm current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. In this paper, we briefly review recent in situ and ground-based observations and theoretical work that have demonstrated a need for an update of the original picture. We present a revised, time-dependent picture of the substorm current wedge that follows its evolution from the initial substorm flows through substorm expansion and recovery, and conclude by identifying open questions.

46 CFR 111.05-29 - Dual voltage direct current systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Dual voltage direct current systems. Each dual voltage direct current system must have a suitably sensitive ground detection system which indicates current in the ground connection, has a range of at least... 46 Shipping 4 2010-10-01 2010-10-01 false Dual voltage direct current systems. 111.05-29 Section...

46 CFR 111.05-29 - Dual voltage direct current systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Dual voltage direct current systems. Each dual voltage direct current system must have a suitably sensitive ground detection system which indicates current in the ground connection, has a range of at least... 46 Shipping 4 2011-10-01 2011-10-01 false Dual voltage direct current systems. 111.05-29 Section...

Fuel consumption of ADS-B and non-ADS-B helicopter operation in the Gulf of Mexico

DOT National Transportation Integrated Search

2013-07-01

Automatic Dependent Surveillance Broadcast (ADSB) is a key enabling technology for the Next Generation Air Transportation System (NextGen) in the United States. The NextGen system replaces the current ground based commandandcontrol syste...

Enhanced ground bounce noise reduction in a low-leakage CMOS multiplier

NASA Astrophysics Data System (ADS)

Verma, Bipin Kumar; Akashe, Shyam; Sharma, Sanjay

2015-09-01

In this paper, various parameters are used to reduce leakage power, leakage current and noise margin of circuits to enhance their performance. A multiplier is proposed with low-leakage current and low ground bounce noise for the microprocessor, digital signal processors (DSP) and graphics engines. The ground bounce noise problem appears when a conventional power-gating circuit transits from sleep-to-active mode. This paper discusses a reduction in leakage current in the stacking power-gating technique by three modes - sleep, active and sleep-to-active. The simulation results are performed on a 4 × 4 carry-save multiplier for leakage current, active power, leakage power and ground bounce noise, and comparison made for different nanoscales. Ground bounce noise is limited to 90%. The leakage current of the circuit is decimated up to 80% and the active power is reduced to 31%. We performed simulations using cadence virtuoso 180 and 45 nm at room temperature at various supply voltages.

Configurable technology development for reusable control and monitor ground systems

NASA Technical Reports Server (NTRS)

Uhrlaub, David R.

1994-01-01

The control monitor unit (CMU) uses configurable software technology for real-time mission command and control, telemetry processing, simulation, data acquisition, data archiving, and ground operations automation. The base technology is currently planned for the following control and monitor systems: portable Space Station checkout systems; ecological life support systems; Space Station logistics carrier system; and the ground system of the Delta Clipper (SX-2) in the Single-Stage Rocket Technology program. The CMU makes extensive use of commercial technology to increase capability and reduce development and life-cycle costs. The concepts and technology are being developed by McDonnell Douglas Space and Defense Systems for the Real-Time Systems Laboratory at NASA's Kennedy Space Center under the Payload Ground Operations Contract. A second function of the Real-Time Systems Laboratory is development and utilization of advanced software development practices.

Challenges in the global-scale quantification of permafrost changes

NASA Astrophysics Data System (ADS)

Gruber, S.

2012-12-01

Permafrost underlies much of Earth's surface and interacts with climate, land-surface phenomena and human systems. This presentation highlights heterogeneity and near-isothermal ground, two simple and well-known phenomena, as important challenges for investigating current and future states of permafrost. Heterogeneity, which can be introduced by e.g., topography, vegetation or subsurface material, is shown to be important for large parts of the global permafrost areas based on two proxies calculated from a global model of permafrost distribution. The model is based on a 1km DEM and NCEP-NCAR as well as CRU TS 2.0 air temperature data. Near-isothermal ground occurs when heat flow into a volume of ground material is accompanied by only a minute temperature change due to the dominance of latent heat transfer near 0°C. This causes our monitoring systems, which are to a large part based on temperature measurements, to lose much of their sensitivity as an instrument to measure permafrost changes. The importance of this is argued for based on (a) the long duration that soil columns are usually exposed to this effect, (b) the abundance of boreholes with temperatures close to 0°C based on the IPY-TSP data set, and (c) the global abundance and relative importance of ground near 0°C. The results presented indicated that systems and methods of gathering permafrost evidence and monitoring data need to better account for heterogeneity and isothermal ground in order to maintain long-term relevance, and that in large-area models sub-grid heterogeneity needs explicit attention.

Geophysical mapping of palsa peatland permafrost

NASA Astrophysics Data System (ADS)

Sjöberg, Y.; Marklund, P.; Pettersson, R.; Lyon, S. W.

2014-10-01

Permafrost peatlands are hydrological and biogeochemical hotspots in the discontinuous permafrost zone. Non-intrusive geophysical methods offer possibility to map current permafrost spatial distributions in these environments. In this study, we estimate the depths to the permafrost table surface and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal thaw frost tables (at ~0.5 m depth), taliks (2.1-6.7 m deep), and the permafrost base (at ~16 m depth) could be detected. Higher occurrences of taliks were discovered at locations with a lower relative height of permafrost landforms indicative of lower ground ice content at these locations. These results highlight the added value of combining geophysical techniques for assessing spatial distribution of permafrost within the rapidly changing sporadic permafrost zone. For example, based on a simple thought experiment for the site considered here, we estimated that the thickest permafrost could thaw out completely within the next two centuries. There is a clear need, thus, to benchmark current permafrost distributions and characteristics particularly in under studied regions of the pan-arctic.

Geophysical mapping of palsa peatland permafrost

NASA Astrophysics Data System (ADS)

Sjöberg, Y.; Marklund, P.; Pettersson, R.; Lyon, S. W.

2015-03-01

Permafrost peatlands are hydrological and biogeochemical hotspots in the discontinuous permafrost zone. Non-intrusive geophysical methods offer a possibility to map current permafrost spatial distributions in these environments. In this study, we estimate the depths to the permafrost table and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal thaw frost tables (at ~0.5 m depth), taliks (2.1-6.7 m deep), and the permafrost base (at ~16 m depth) could be detected. Higher occurrences of taliks were discovered at locations with a lower relative height of permafrost landforms, which is indicative of lower ground ice content at these locations. These results highlight the added value of combining geophysical techniques for assessing spatial distributions of permafrost within the rapidly changing sporadic permafrost zone. For example, based on a back-of-the-envelope calculation for the site considered here, we estimated that the permafrost could thaw completely within the next 3 centuries. Thus there is a clear need to benchmark current permafrost distributions and characteristics, particularly in under studied regions of the pan-Arctic.

Characteristic investigation and control of a modular multilevel converter-based HVDC system under single-line-to-ground fault conditions

DOE PAGES

Shi, Xiaojie; Wang, Zhiqiang; Liu, Bo; ...

2014-05-16

This paper presents the analysis and control of a multilevel modular converter (MMC)-based HVDC transmission system under three possible single-line-to-ground fault conditions, with special focus on the investigation of their different fault characteristics. Considering positive-, negative-, and zero-sequence components in both arm voltages and currents, the generalized instantaneous power of a phase unit is derived theoretically according to the equivalent circuit model of the MMC under unbalanced conditions. Based on this model, a novel double-line frequency dc-voltage ripple suppression control is proposed. This controller, together with the negative-and zero-sequence current control, could enhance the overall fault-tolerant capability of the HVDCmore » system without additional cost. To further improve the fault-tolerant capability, the operation performance of the HVDC system with and without single-phase switching is discussed and compared in detail. Lastly, simulation results from a three-phase MMC-HVDC system generated with MATLAB/Simulink are provided to support the theoretical analysis and proposed control schemes.« less

Benefits Derived From Laser Ranging Measurements for Orbit Determination of the GPS Satellite Orbit

NASA Technical Reports Server (NTRS)

Welch, Bryan W.

2007-01-01

While navigation systems for the determination of the orbit of the Global Position System (GPS) have proven to be very effective, the current research is examining methods to lower the error in the GPS satellite ephemerides below their current level. Two GPS satellites that are currently in orbit carry retro-reflectors onboard. One notion to reduce the error in the satellite ephemerides is to utilize the retro-reflectors via laser ranging measurements taken from multiple Earth ground stations. Analysis has been performed to determine the level of reduction in the semi-major axis covariance of the GPS satellites, when laser ranging measurements are supplemented to the radiometric station keeping, which the satellites undergo. Six ground tracking systems are studied to estimate the performance of the satellite. The first system is the baseline current system approach which provides pseudo-range and integrated Doppler measurements from six ground stations. The remaining five ground tracking systems utilize all measurements from the current system and laser ranging measurements from the additional ground stations utilized within those systems. Station locations for the additional ground sites were taken from a listing of laser ranging ground stations from the International Laser Ranging Service. Results show reductions in state covariance estimates when utilizing laser ranging measurements to solve for the satellite s position component of the state vector. Results also show dependency on the number of ground stations providing laser ranging measurements, orientation of the satellite to the ground stations, and the initial covariance of the satellite's state vector.

Effects of finite ground plane on the radiation characteristics of a circular patch antenna

NASA Astrophysics Data System (ADS)

Bhattacharyya, Arun K.

1990-02-01

An analytical technique to determine the effects of finite ground plane on the radiation characteristics of a microstrip antenna is presented. The induced currents on the ground plane and on the upper surface of the patch are determined from the discontinuity of the near field produced by the equivalent magnetic current source on the physical aperture of the patch. The radiated fields contributed by the induced current on the ground plane and the equivalent sources on the physical aperture yield the radiation pattern of the antenna. Radiation patterns of the circular patch with finite ground plane size are computed and compared with the experimental data, and the agreement is found to be good. The radiation pattern, directive gain, and input impedance are found to vary widely with the ground plane size.

Ground-water contamination at Wurtsmith Air Force Base, Michigan

USGS Publications Warehouse

Stark, J.R.; Cummings, T.R.; Twenter, F.R.

1983-01-01

A sand and gravel aquifer of glacial origin underlies Wurtsmith Air Force Base in northeastern lower Michigan. The aquifer overlies a thick clay layer at an average depth of 65 feet. The water table is about 10 feet below land surface in the western part of the Base and about 25 feet below land surface in the eastern part. A ground-water divide cuts diagonally across the Base from northwest to southeast. South of the divide, ground water flows to the Au Sable River; north of the divide, it flows to Van Etten Creek and Van Etten Lake. Mathematical models were used to aid in calculating rates of groundwater flow. Rates range from about 0.8 feet per day in the eastern part of the Base to about 0.3 feet per day in the western part. Models also were used as an aid in making decisions regarding purging of contaminated water from the aquifer. In 1977, trichloroethylene was detected in the Air Force Base water-supply system. It had leaked from a buried storage tank near Building 43 in the southeastern part of the Base and moved northeastward under the influence of the natural ground-water gradient and the pumping of Base water-supply wells. In the most highly contaminated part of the plume, concentrations are greater than 1,000 micrograms per liter. Current purge pumping is removing some of the trichloroethylene, and seems to have arrested its eastward movement. Pumping of additional purge wells could increase the rate of removal. Trichloroethylene has also been detected in ground water in the vicinity of the Base alert apron, where a plume from an unknown source extends northeastward off Base. A smaller, less well-defined area of contamination also occurs just north of the larger plume. Trichloroethylene, identified near the waste-treatment plant, seepage lagoons, and the northern landfill area, is related to activities and operations in these areas. Dichloroethylene and trichloroethylene occur in significant quantities westward of Building 43, upgradient from the major spill site. Benzene, indicative of ground-water contamination by a fuel substance, occurs in an area northeast of the bulk-fuel storage area. Analysis of a variety of chemical, physical, and biologic characteristics of water on the Base indicate that there is a measurable affect on ground-water quality from landfills, the seepage lagoon, and the waste-treatment plant.

JPRS Report, Science & Technology, Europe & Latin America.

DTIC Science & Technology

1987-08-28

Rhine Westfalia) has recently agreed to purchase a new high performance laser which is supposed to • prepare the ground for new processing and...Transition Temperature Lies Within a Very Limited Area"] [Excerpts] VDI-N, Bochum, 15/5/87— High temperature, high current superconductors with a transition...applications of superconductive materials. Dr Kahn was able to produce a high temperature superconductor with high current flow based on the known oxide

Microbial Monitoring of Common Opportunistic Pathogens by Comparing Multiple Real-time PCR Platforms for Potential Space Applications

NASA Technical Reports Server (NTRS)

Roman, Monserrate C.; Jones, Kathy U.; Oubre, Cherie M.; Castro, Victoria; Ott, Mark C.; Birmele, Michele; Venkateswaran, Kasthuri J.; Vaishampayan, Parag A.

2013-01-01

Current methods for microbial detection: a) Labor & time intensive cultivation-based approaches that can fail to detect or characterize all cells present. b) Requires collection of samples on orbit and transportation back to ground for analysis. Disadvantages to current detection methods: a) Unable to perform quick and reliable detection on orbit. b) Lengthy sampling intervals. c) No microbe identification.

STREAM PROCESSING ALGORITHMS FOR DYNAMIC 3D SCENE ANALYSIS

DTIC Science & Technology

2018-02-15

23 9 Ground truth creation based on marked building feature points in two different views 50 frames apart in...between just two views , each row in the current figure represents a similar assessment however between one camera and all other cameras within the dataset...BA4S. While Fig. 44 depicted the epipolar lines for the point correspondences between just two views , the current figure represents a similar

A mobile test facility based on a magnetic cumulative generator to study the stability of the power plants under impact of lightning currents

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

Shurupov, A. V.; Zavalova, V. E., E-mail: zavalova@fites.ru; Kozlov, A. V.

The report presents the results of the development and field testing of a mobile test facility based on a helical magnetic cumulative generator (MCGTF). The system is designed for full-scale modeling of lightning currents to study the safety of power plants of any type, including nuclear power plants. Advanced technologies of high-energy physics for solving both engineering and applied problems underlie this pilot project. The energy from the magnetic cumulative generator (MCG) is transferred to a high-impedance load with high efficiency of more than 50% using pulse transformer coupling. Modeling of the dynamics of the MEG that operates in amore » circuit with lumped parameters allows one to apply the law of inductance output during operation of the MCG, thus providing the required front of the current pulse in the load without using any switches. The results of field testing of the MCGTF are presented for both the ground loop and the model load. The ground loop generates a load resistance of 2–4 Ω. In the tests, the ohmic resistance of the model load is 10 Ω. It is shown that the current pulse parameters recorded in the resistive-inductive load are close to the calculated values.« less

System for detecting and limiting electrical ground faults within electrical devices

DOEpatents

Gaubatz, Donald C.

1990-01-01

An electrical ground fault detection and limitation system for employment with a nuclear reactor utilizing a liquid metal coolant. Elongate electromagnetic pumps submerged within the liquid metal coolant and electrical support equipment experiencing an insulation breakdown occasion the development of electrical ground fault current. Without some form of detection and control, these currents may build to damaging power levels to expose the pump drive components to liquid metal coolant such as sodium with resultant undesirable secondary effects. Such electrical ground fault currents are detected and controlled through the employment of an isolated power input to the pumps and with the use of a ground fault control conductor providing a direct return path from the affected components to the power source. By incorporating a resistance arrangement with the ground fault control conductor, the amount of fault current permitted to flow may be regulated to the extent that the reactor may remain in operation until maintenance may be performed, notwithstanding the existence of the fault. Monitors such as synchronous demodulators may be employed to identify and evaluate fault currents for each phase of a polyphase power, and control input to the submerged pump and associated support equipment.

49 CFR 234.213 - Grounds.

Code of Federal Regulations, 2010 CFR

2010-10-01

... current power distribution circuits that are grounded in the interest of safety; and common return wires... Maintenance Standards § 234.213 Grounds. Each circuit that affects the proper functioning of a highway-rail... permit a current flow of 75 percent or more of the release value of any relay or electromagnetic device...

Building an Intelligent Water Information System - American River Prototype

NASA Astrophysics Data System (ADS)

Glaser, S. D.; Bales, R. C.; Conklin, M. H.

2013-12-01

With better management, California's existing water supplies could go further to meeting the needs of the state's urban and agricultural uses. For example, California's water reservoirs are currently controlled and regulated using forecasts based upon more than 75 years of historical data. In the face of global climate change, these forecasts are becoming increasingly inadequate to precisely manage water resources. We propose implementing Leveraging the newest frontiers of information technology, we are developing a basin-scale real-time intelligent water infrastructure system that enables more information-intensive decision support. The complete system is made up of four key components. First, a strategically deployed ground-observation system will complement satellite measurements and provide continuous and accurate estimates of snowpack, soil moisture, vegetation state and energy balance across watersheds. Using our recently developed but mature technologies, we deliver measurements of hydrologic variables over a multi- tiered network of wireless sensor arrays, with a granularity of time and space previously unheard of. Second, satellite and aircraft remote sensing provide the only practical means of spatially continuous basin-wide measurement and monitoring of snow properties, vegetation characteristics and other watershed conditions. The ground-based system is designed to blend with remote sensing data on Sierra Nevada snow properties, and provide value-added products of unprecedented spatial detail and accuracy that are useable on a watershed level. Third, together the satellite and ground-based data make possible the updating of forecast tools, and routine use of physically based hydrologic models. The decision-support framework will provide tools to extract and visualize information of interest from the measured and modeled data, to assess uncertainties, and to optimize operations. Fourth, the advanced cyber infrastructure blends and transforms the numbers recorded by sensors into information in the form that is useful for decision-making. In a sense it 'monetizes' the data. It is the cyber infrastructure that links measurements, data processing, models and users. System software must provide flexibility for multiple types of access from user queries to automated and direct links with analysis tools and decision-support systems. We are currently installing a basin-scale ground-based sensor network focusing on measurements of snowpack, solar radiation, temperature, rH and soil moisture across the American River basin. Although this is a research network, it also provides core elements of a full ground-based operational system.

Space Weather Studies Using Ground-based Experimental Complex in Kazakhstan

NASA Astrophysics Data System (ADS)

Kryakunova, O.; Yakovets, A.; Monstein, C.; Nikolayevskiy, N.; Zhumabayev, B.; Gordienko, G.; Andreyev, A.; Malimbayev, A.; Levin, Yu.; Salikhov, N.; Sokolova, O.; Tsepakina, I.

2015-12-01

Kazakhstan ground-based experimental complex for space weather study is situated near Almaty. Results of space environment monitoring are accessible via Internet on the web-site of the Institute of Ionosphere (http://www.ionos.kz/?q=en/node/21) in real time. There is a complex database with hourly data of cosmic ray intensity, geomagnetic field intensity, and solar radio flux at 10.7 cm and 27.8 cm wavelengths. Several studies using those data are reported. They are an estimation of speed of a coronal mass ejection, a study of large scale traveling distrubances, an analysis of geomagnetically induced currents using the geomagnetic field data, and a solar energetic proton event on 27 January 2012.

Study on Spacelab software development and integration concepts

NASA Technical Reports Server (NTRS)

1974-01-01

A study was conducted to define the complexity and magnitude of the Spacelab software challenge. The study was based on current Spacelab program concepts, anticipated flight schedules, and ground operation plans. The study was primarily directed toward identifying and solving problems related to the experiment flight application and tests and checkout software executing in the Spacelab onboard command and data management subsystem (CDMS) computers and electrical ground support equipment (EGSE). The study provides a conceptual base from which it is possible to proceed into the development phase of the Software Test and Integration Laboratory (STIL) and establishes guidelines for the definition of standards which will ensure that the total Spacelab software is understood prior to entering development.

Cockpit display of hazardous wind shear information

NASA Technical Reports Server (NTRS)

Wanke, Craig; Hansman, R. John, Jr.

1990-01-01

Information on cockpit display of wind shear information is given in viewgraph form. Based on the current status of windshear sensors and candidate data dissemination systems, the near-term capabilities for windshear avoidance will most likely include: (1) Ground-based detection: TDWR (Terminal Doppler Weather Radar), LLWAS (Low-Level Windshear Alert System), Automated PIREPS; (2) Ground-Air datalinks: Air traffic control voice channels, Mode-S digital datalink, ACARS alphanumeric datalink. The possible datapaths for integration of these systems are illustrated in a diagram. In the future, airborne windshear detection systems such as lidars, passive IR detectors, or airborne Doppler radars may also become available. Possible future datalinks include satellite downlink and specialized en route weather channels.

Hydrological research in Ethiopia

NASA Astrophysics Data System (ADS)

Gebremichael, M.

2012-12-01

Almost all major development problems in Ethiopia are water-related: food insecurity, low economic development, recurrent droughts, disastrous floods, poor health conditions, and low energy condition. In order to develop and manage existing water resources in a sustainable manner, knowledge is required about water availability, water quality, water demand in various sectors, and the impacts of water resource projects on health and the environment. The lack of ground-based data has been a major challenge for generating this knowledge. Current advances in remote sensing and computer simulation technology could provide alternative source of datasets. In this talk, I will present the challenges and opportunities in using remote sensing datasets and hydrological models in regions such as Africa where ground-based datasets are scarce.

Performance and Calibration of H2RG Detectors and SIDECAR ASICs for the RATIR Camera

NASA Technical Reports Server (NTRS)

Fox, Ori D.; Kutyrev, Alexander S.; Rapchun, David A.; Klein, Christopher R.; Butler, Nathaniel R.; Bloom, Josh; de Diego, Jos A.; Simn Farah, Alejandro D.; Gehrels, Neil A.; Georgiev, Leonid;

Simple system for locating ground loops.

PubMed

Bellan, P M

2007-06-01

A simple low-cost system for rapid identification of the cables causing ground loops in complex instrumentation configurations is described. The system consists of an exciter module that generates a 100 kHz ground loop current and a detector module that determines which cable conducts this test current. Both the exciter and detector are magnetically coupled to the ground circuit so there is no physical contact to the instrumentation system under test.

Estimation of vulnerability functions based on a global earthquake damage database

NASA Astrophysics Data System (ADS)

Spence, R. J. S.; Coburn, A. W.; Ruffle, S. J.

2009-04-01

Developing a better approach to the estimation of future earthquake losses, and in particular to the understanding of the inherent uncertainties in loss models, is vital to confidence in modelling potential losses in insurance or for mitigation. For most areas of the world there is currently insufficient knowledge of the current building stock for vulnerability estimates to be based on calculations of structural performance. In such areas, the most reliable basis for estimating vulnerability is performance of the building stock in past earthquakes, using damage databases, and comparison with consistent estimates of ground motion. This paper will present a new approach to the estimation of vulnerabilities using the recently launched Cambridge University Damage Database (CUEDD). CUEDD is based on data assembled by the Martin Centre at Cambridge University since 1980, complemented by other more-recently published and some unpublished data. The database assembles in a single, organised, expandable and web-accessible database, summary information on worldwide post-earthquake building damage surveys which have been carried out since the 1960's. Currently it contains data on the performance of more than 750,000 individual buildings, in 200 surveys following 40 separate earthquakes. The database includes building typologies, damage levels, location of each survey. It is mounted on a GIS mapping system and links to the USGS Shakemaps of each earthquake which enables the macroseismic intensity and other ground motion parameters to be defined for each survey and location. Fields of data for each building damage survey include: · Basic earthquake data and its sources · Details of the survey location and intensity and other ground motion observations or assignments at that location · Building and damage level classification, and tabulated damage survey results · Photos showing typical examples of damage. In future planned extensions of the database information on human casualties will also be assembled. The database also contains analytical tools enabling data from similar locations, building classes or ground motion levels to be assembled and thus vulnerability relationships derived for any chosen ground motion parameter, for a given class of building, and for particular countries or regions. The paper presents examples of vulnerability relationships for particular classes of buildings and regions of the world, together with the estimated uncertainty ranges. It will discuss the applicability of such vulnerability functions in earthquake loss assessment for insurance purposes or for earthquake risk mitigation.

Slit Effect of Common Ground Patterns in Affecting Cross-Talk Noise between Two Parallel Signal Traces on Printed Circuit Boards

NASA Astrophysics Data System (ADS)

Maeno, Tsuyoshi; Sakurai, Yukihiko; Unou, Takanori; Ichikawa, Kouji; Fujiwara, Osamu

It is well-known that electromagnetic (EM) disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns with slits. To evaluate the noise current outflows from the PCBs of this kind, we previously measured noise current outflows from four types of simple three-layer PCBs having two perpendicular signal traces and different ground patterns with/without slits, and showed that slits on a ground pattern allow conducted noise currents to flow out from PCBs, while the levels for the symmetric slits ground type are smaller compared to the case for two asymmetric slits ground types. In the present study, to further investigate the above finding, we fabricated six types of simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits, and measured the cross-talk noise between the traces. As a result, we found that the ground patterns with the slits perpendicular to the traces increase the cross-talk noise levels, which are larger by 19-42 dB than those for the ground pattern with no slits, while the ground patterns with the slits in parallel with the traces can suppress the noise levels, which are slightly smaller by 2.5-4.5 dB compared to the case for the no-slit ground pattern. These results were confirmed by the FDTD simulation, and were also qualitatively explained from an equivalent bridge circuit model we previously proposed.

Apparatus for in situ heating and vitrification

DOEpatents

Buelt, James L.; Oma, Kenton H.; Eschbach, Eugene A.

1994-01-01

An apparatus for decontaminating ground areas where toxic chemicals are buried includes a plurality of spaced electrodes located in the ground and to which a voltage is applied for bringing about current flow. Power delivered to the ground volatilizes the chemicals that are then collected and directed to a gas treatment system. A preferred form of the invention employs high voltage arc discharge between the electrodes for heating a ground region to relatively high temperatures at relatively low power levels. Electrodes according to the present invention are provided with preferentially active lower portions between which current flows for the purpose of soil heating or for soil melting and vitrification. Promoting current flow below ground level avoids predominantly superficial treatment and increases electrode life.

Apparatus for in situ heating and vitrification

DOEpatents

Buelt, J.L.; Oma, K.H.; Eschbach, E.A.

1994-05-31

An apparatus for decontaminating ground areas where toxic chemicals are buried includes a plurality of spaced electrodes located in the ground and to which a voltage is applied for bringing about current flow. Power delivered to the ground volatilizes the chemicals that are then collected and directed to a gas treatment system. A preferred form of the invention employs high voltage arc discharge between the electrodes for heating a ground region to relatively high temperatures at relatively low power levels. Electrodes according to the present invention are provided with preferentially active lower portions between which current flows for the purpose of soil heating or for soil melting and vitrification. Promoting current flow below ground level avoids predominantly superficial treatment and increases electrode life. 15 figs.

Measurements of CO2 Column Abundance in the Low Atmosphere Using Ground Based 1.6 μm CO2 DIAL

NASA Astrophysics Data System (ADS)

Abo, M.; Shibata, Y.; Nagasawa, C.

2017-12-01

Changes in atmospheric carbon dioxide (CO2) concentration are believed to produce the largest radiative forcing for the current climate system. Accurate predictions of atmospheric CO2 concentration rely on the knowledge of its sinks and sources, transports, and its variability with time. Although this knowledge is currently unsatisfactory, numerical models use it as a way in simulating CO2 fluxes. Validating and improving the global atmospheric transport model, therefore, requires precise measurement of the CO2 concentration profile. There are two further variations on Lidar: the differential absorption Lidar (DIAL) and the integrated path differential absorption (IPDA) Lidar. DIAL/IPDA are basically for profile/total column measurement, respectively. IPDA is a special case of DIAL and can measure the total column-averaged mixing ratio of trace gases using return signals from the Earth's surface or from thick clouds based on an airborne or a satellite. We have developed a ground based 1.6 μm DIAL to measure vertical CO2 mixing ratio profiles from 0.4 to 2.5 km altitude. The goals of the CO2 DIAL are to produce atmospheric CO2 mixing ratio measurements with much smaller seasonal and diurnal biases from the ground surface. But, in the ground based lidar, return signals from around ground surface are usually suppressed in order to handle the large dynamic range. To receive the return signals as near as possible from ground surface, namely, the field of view (FOV) of the telescope must be wide enough to reduce the blind range of the lidar. While the return signals from the far distance are very weak, to enhance the sensitivity and heighten the detecting distance, the FOV must be narrow enough to suppress the sky background light, especially during the daytime measurements. To solve this problem, we propose a total column measurement method from the ground surface to 0.4 km altitude. Instead of strong signals from thick clouds such as the IPDA, the proposed method uses atmospheric return signals from 0.4 km altitude. Although laser outputs of two wavelengths, which are the system parameter of DIAL, are canceled, the proposed method needs to constantly monitor laser outputs. When the laser output ratio with two wavelengths is 1.0 ± 0.01, the error simulation result of the CO2 mixing ratio is 420.0 ± 3.9 ppm.

Comparison of Ground-Based and Airborne Function Allocation Concepts for NextGen Using Human-In-The-Loop Simulations

NASA Technical Reports Server (NTRS)

Wing, David J.; Prevot, Thomas; Murdoch, Jennifer L.; Cabrall, Christopher D.; Homola, Jeffrey R.; Martin, Lynne H.; Mercer, Joey S.; Hoadley, Sherwood T.; Wilson, Sara R.; Hubbs, Clay E.;

Second generation OH suppression filters using multicore fibers

NASA Astrophysics Data System (ADS)

Haynes, R.; Birks, T. A.; Bland-Hawthorn, J.; Cruz, J. L.; Diez, A.; Ellis, S. C.; Haynes, D.; Krämer, R. G.; Mangan, B. J.; Min, S.; Murphy, D. F.; Nolte, S.; Olaya, J. C.; Thomas, J. U.; Trinh, C. Q.; Tünnermann, A.; Voigtländer, Christian

2012-09-01

Ground based near-infrared observations have long been plagued by poor sensitivity when compared to visible observations as a result of the bright narrow line emission from atmospheric OH molecules. The GNOSIS instrument recently commissioned at the Australian Astronomical Observatory uses Photonic Lanterns in combination with individually printed single mode fibre Bragg gratings to filter out the brightest OH-emission lines between 1.47 and 1.70μm. GNOSIS, reported in a separate paper in this conference, demonstrates excellent OH-suppression, providing very “clean” filtering of the lines. It represents a major step forward in the goal to improve the sensitivity of ground based near-infrared observation to that possible at visible wavelengths, however, the filter units are relatively bulky and costly to produce. The 2nd generation fibre OH-Suppression filters based on multicore fibres are currently under development. The development aims to produce high quality, cost effective, compact and robust OH-Suppression units in a single optical fibre with numerous isolated single mode cores that replicate the function and performance of the current generation of “conventional” photonic lantern based devices. In this paper we present the early results from the multicore fibre development and multicore fibre Bragg grating imprinting process.

Review and evaluation of models that produce trip tables from ground counts : interim report.

DOT National Transportation Integrated Search

1996-01-01

This research effort was motivated by the desires of planning agencies to seek alternative methods of deriving current or base year Origin-Destination (O-D) trip tables without adopting conventional O-D surveys that are expensive, time consuming and ...

National Airspace System : persistent problems in FAA's new navigation system highlight need for periodic reevaluation

DOT National Transportation Integrated Search

2000-06-01

Currently, the Federal Aviation Administration (FAA) relies principally on a ground-based navigation system that uses various types of equipment to assist pilots in navigating their assigned routes and to provide them with guidance for landing their ...

Comparison of current Shuttle and pre-Challenger flight suit reach capability during launch accelerations

NASA Technical Reports Server (NTRS)

Bagian, James P.; Schafer, Lauren E.

1992-01-01

The Challenger accident prompted the creation of a crew escape system which replaced the former Launch Entry Helmet (LEH) ensemble with the current Launch Entry Suit (LES). However, questions were raised regarding the impact of this change on crew reach capability. This study addressed the question of reach capability and its effects on realistic ground-based training for Space Shuttle missions. Eleven subjects performed reach sweeps in both the LEH and LES suits during 1 and 3 Gx acceleration trials in the Brooks AFB centrifuge. These reach sweeps were recorded on videotape and subsequently analyzed using a 3D motion analysis system. The ANOVA procedure of the Statistical Analysis System program was used to evaluate differences in forward and overhead reach. The results showed that the LES provided less reach capability than its predecessor, the LEH. This study also demonstrated that, since there was no substantial difference between 1 and 3 Gx reach sweeps in the LES, realistic Shuttle launch training may be accomplished in ground based simulators.

Properties of M components from currents measured at triggered lightning channel base

NASA Astrophysics Data System (ADS)

Thottappillil, Rajeev; Goldberg, Jon D.; Rakov, Vladimir A.; Uman, Martin A.; Fisher, Richard J.; Schnetzer, George H.

1995-12-01

Channel base currents from triggered lightning were measured at the NASA Kennedy Space Center, Florida, during summer 1990 and at Fort McClellan, Alabama, during summer 1991. An analysis of the return stroke data and overall continuing current data has been published by Fisher et al. [1993]. Here an analysis is given of the impulsive processes, called M components, that occur during the continuing current following return strokes. The 14 flashes analyzed contain 37 leader-return stroke sequences and 158 M components, both processes lowering negative charge from cloud to ground. Statistics are presented for the following M current pulse parameters: magnitude, rise time, duration, half-peak width, preceding continuing current level, M interval, elapsed time since the return stroke, and charge transferred by the M current pulse. A typical M component in triggered lightning is characterized by a more or less symmetrical current pulse having an amplitude of 100-200 A (2 orders of magnitude lower than that for a typical return stroke [Fisher et al., 1993]), a 10-90% rise time of 300-500 μs (3 orders of magnitude larger than that for a typical return stroke [Fisher et al., 1993]), and a charge transfer to ground of the order of 0.1 to 0.2 C (1 order of magnitude smaller than that for a typical subsequent return stroke pulse [Berger et al., 1975]). About one third of M components transferred charge greater than the minimum charge reported by Berger et al. [1975] for subsequent leader-return stroke sequences. No correlation was found between either the M charge or the magnitude of the M component current (the two are moderately correlated) and any other parameter considered. M current pulses occurring soon after the return stroke tend to have shorter rise times, shorter durations, and shorter M intervals than those which occur later. M current pulses were observed to be superimposed on continuing currents greater than 30 A or so, with one exception out of 140 cases, wherein the continuing current level was measured to be about 20 A. The first M component virtually always (one exception out of 34 cases) occurred within 4 ms of the return stroke. This relatively short separation time between return stroke and the first M component, coupled with the observation of Fisher et al. [1993] that continuing currents lasting longer than 10 ms never occur without M current pulses, implies that the M component is a necessary feature of the continuing current mode of charge transfer to ground.

The optical very large array and its moon-based version

NASA Technical Reports Server (NTRS)

Labeyrie, Antoine

1992-01-01

An Optical Very Large Array (OVLA) is currently in early prototyping stages for ground-based sites, such as Mauna Kea and perhaps the VLT site in Chile. Its concept is also suited for a moon-based interferometer. With a ring of bi-dimensionally mobile telescopes, there is maximal flexibility in the aperture pattern, and no need for delay lines. A circular configuration of many free-flying telescopes, TRIO, is also considered for space interferometers. Finally, the principle of gaseous mirrors may become applicable for moon-based optical arrays. Fifteen years after the first coherent linkage of two optical telescopes, the design of an ambitious imaging array, the OVLA, is now well advanced. Two 1.5 m telescopes have been built and now provide astronomical results. Elements of the OVLA are under construction. Although primarily conceived for ground-based sites, the OVLA structure appears to meet the essential requirements for operation on the Moon.

Multimission Modular Spacecraft Ground Support Software System (MMS/GSSS) state-of-the-art computer systems/ compatibility study

NASA Technical Reports Server (NTRS)

1980-01-01

The compatibility of the Multimission Modular Spacecraft (MMS) Ground Support Software System (GSSS), currently operational on a ModComp IV/35, with the VAX 11/780 system is discussed. The compatibility is examined in various key areas of the GSSS through the results of in depth testing performed on the VAX 11/780 and ModComp IV/35 systems. The compatibility of the GSSS with the ModComp CLASSIC is presented based upon projections from ModComp supplied literature.

Potential of laser for SPS power transmission

NASA Technical Reports Server (NTRS)

Bain, C. N.

1978-01-01

Research on the feasibility of using a laser subsystem as an additional option for the transmission of the satellite power system (STS) power is presented. Current laser work and predictions for future laser performance provide a level of confidence that the development of a laser power transmission system is technologically feasible in the time frame required to develop the SBS. There are significant economic advantages in lower ground distribution costs and a reduction of more than two orders of magnitude in real estate requirements for ground based receiving/conversion sites.

Solar Spicules Near and at the Limb, Observed from Hinode

NASA Technical Reports Server (NTRS)

Sterling, A. C.; Moore, R. L.

2010-01-01

Solar spicules appear as narrow jets emanating from the chromosphere and extending into the corona. They have been observed for over a hundred years, mainly in chromospheric spectral lines such as H-alpha. Because they are at the limit of visibility of ground-based instruments, their nature has long been a puzzle. In recent years however, vast progress has been made in understanding them both theoretically and observationally, as spicule studies have undergone a revolution because of the superior resolution and time cadence of ground-based and space-based instruments. Even more rapid progress is currently underway, due to the Solar Optical Telescope (SOT) instrument on the Hinode spacecraft. Here we present observations of spicules from Hinode SOT, as seen near the limb with the Ca II filtergraph.

Liquid Phase Miscibility Gap Materials

NASA Technical Reports Server (NTRS)

Gelles, S. H.; Markworth, A. J.

1985-01-01

The manner in which the microstructural features of liquid-phase miscibility gap alloys develop was determined. This will allow control of the microstructures and the resultant properties of these alloys. The long-duration low gravity afforded by the shuttle will allow experiments supporting this research to be conducted with minimal interference from buoyancy effects and gravitationally driven convection currents. Ground base studies were conducted on Al-In, Cu-Pb, and Te-Tl alloys to determine the effect of cooling rate, composition, and interfacial energies on the phase separation and solidification processes that influence the development of microstructure in these alloys. Isothermal and directional cooling experiments and simulations are conducted. The ground based activities are used as a technological base from which flight experiments formulated and to which these flight experiments are compared.

Bubbles, voids, and bumps in time: The new cosmology

NASA Astrophysics Data System (ADS)

Cornell, James

The history and current status of theoretical and observational cosmology are examined in chapters based on the Lowell Lectures, given in Boston and Washington DC in spring 1987. Topics addressed include the Aristotelian, Copernican, Newtonian, and Einsteinian universes; the measurement of the universe (redshifts and standard candles); mapping the universe (slices and bubbles); dark matter and missing mass; and the big bang and cosmic inflation. Six basic outstanding problems are identified, and the potential contributions of planned ground-based and space observatories to their solution are discussed. Particular attention is given to CCD detectors for large ground-based telescopes, the VLA, VLBI arrays, the ESO Very Large Telescope, the 10-m Keck telescope on Mauna Kea, the Hubble Space Telescope, the Gamma-Ray Observatory, and the Advanced X-ray Astrophysics Facility.

Laser Guide Star Based Astrophysics at Lick Observatory

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

Max, C; Gavel, D.; Friedman, H.

2000-03-10

The resolution of ground-based telescopes is typically limited to {approx}1 second of arc because of the blurring effects of atmospheric turbulence. Adaptive optics (AO) technology senses and corrects for the optical distortions due to turbulence hundreds of times per second using high-speed sensors, computers, deformable mirror, and laser technology. The goal of this project is to make AO systems widely useful astronomical tools providing resolutions up to an order of magnitude better than current, ground-based telescopes. Astronomers at the University of California Lick Observatory at Mt. Hamilton now routinely use the LLNL developed AO system for high resolution imaging ofmore » astrophysical objects. We report here on the instrument development progress and on the science observations made with this system during this 3-year ERI project.« less

Lidar-Based Estimates of Above-Ground Biomass in the Continental US and Mexico Using Ground, Airborne, and Satellite Observations

NASA Technical Reports Server (NTRS)

Nelson, Ross; Margolis, Hank; Montesano, Paul; Sun, Guoqing; Cook, Bruce; Corp, Larry; Andersen, Hans-Erik; DeJong, Ben; Pellat, Fernando Paz; Fickel, Thaddeus;

A ground-water-quality monitoring program for Nevada

USGS Publications Warehouse

Nowlin, Jon O.

1986-01-01

A program was designed for the systematic monitoring of ground-water quality in Nevada. Basic hydrologic and water-quality principles are discussed in the formulation of a rational approach to developing a statewide monitoring program. A review of ground-water monitoring efforts in Nevada through 1977 indicates that few requirements for an effective statewide program are being met. A suggested program has been developed that consists of five major elements: (1) A Background-Quality Network to assess the existing water quality in Nevada aquifers, (2) a Contamination Source Inventory of known or potential threats to ground-water quality, (3) Surveillance Networks to monitor ground-water quality in selected hydrographic areas, (4) Intensive Surveys of individual instances of known or potential ground-water contamination, and (5) Ground-Water Data File to manage data generated by the other monitoring elements. Two indices have been developed to help assign rational priorities for monitoring ground water in the 255 hydrographic areas of Nevada: (1) A Hydrographic-Area Priority Index for surveillance monitoring, and (2) A Development-Potential Index for background monitoring of areas with little or no current development. Requirements for efficient management of data from ground-water monitoring are discussed and the three major systems containing Nevada ground-water data are reviewed. More than 11,000 chemical analyses of ground water have been acquired from existing systems and incorporated into a prototype data base.

MANGO - A Magnetogram Analysis Service for Enhancement of the Heliophysics Data Environment

NASA Astrophysics Data System (ADS)

Bargatze, L. F.

2011-12-01

The Heliophysics Data Environment Enhancement program supports efforts to integrate data services for conducting research of solar-terrestrial interactions. MANGO, Magnetogram Analysis for the Network of Geophysical Observatories, is a service that is directed at Heliophysics researchers interested in processing magnetic field data from ground magnetometers. Ground magnetograms are essential for monitoring the response of the magnetosphere to solar wind coupling. For instance, it is difficult to understand how spacecraft particle and field variations fit in context of activity throughout the global magnetospheric system without using ground magnetic field data. The MANGO service package allows one to decompose ground magnetic field variations and estimate the relative contributions from secular, diurnal, ring current, and auroral current systems. The MANGO service package leverages the SPASE metadata registries of the Virtual Magnetospheric Observatory (VMO) to compile a list of available magnetogram data products. Currently, MANGO provides access to over 900 data products from about 350 ground magnetic field stations located around the globe. The VMO SPASE Granule registry contains ~150,000 files that comprise the MANGO relevant data products. And, the VMO Granule registry count is steadily increasing as more data products are described and ingested. Data selection from the distributed network of stations is naturally aided by using a world map to display the set of observatories. The MANGO web site (http://mango.igpp.ucla.edu), plots stations on a map that have data products, which meet user-defined criteria based on time of observation, station location, time cadence, magnetometer chain, etc. Note that Many of the ground magnetogram and geomagnetic index data products relevant to the MANGO effort are only available from their data providers in formats that allow the data to be packed. The formats used, and there are many types, save time in file retrieval and space on disk but resulting files require format conversion routines (i.e., from IAGA- 2002, WDC formats to flat ASCII tables) or specialized readers that unpack the desired magnetogram and index data. At present, 408 World Data Center ground magnetic field data products and the ring current Dst index data set have been converted into flat ASCII files, described via SPASE, and registered in the VMO metadata registry as a value-added service to users.

A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

NASA Technical Reports Server (NTRS)

Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

2000-01-01

Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

Investigating the auroral electrojets with low altitude polar orbiting satellites

NASA Astrophysics Data System (ADS)

Moretto, T.; Olsen, N.; Ritter, P.; Lu, G.

2002-07-01

Three geomagnetic satellite missions currently provide high precision magnetic field measurements from low altitude polar orbiting spacecraft. We demonstrate how these data can be used to determine the intensity and location of the horizontal currents that flow in the ionosphere, predominantly in the auroral electrojets. First, we examine the results during a recent geomagnetic storm. The currents derived from two satellites at different altitudes are in very good agreement, which verifies good stability of the method. Further, a very high degree of correlation (correlation coefficients of 0.8 0.9) is observed between the amplitudes of the derived currents and the commonly used auroral electrojet indices based on magnetic measurements at ground. This points to the potential of defining an auroral activity index based on the satellite observations, which could be useful for space weather monitoring. A specific advantage of the satellite observations over the ground-based magnetic measurements is their coverage of the Southern Hemisphere, as well as the Northern. We utilize this in an investigation of the ionospheric currents observed in both polar regions during a period of unusually steady interplanetary magnetic field with a large negative Y-component. A pronounced asymmetry is found between the currents in the two hemispheres, which indicates real inter-hemispheric differences beyond the mirror-asymmetry between hemispheres that earlier studies have revealed. The method is also applied to another event for which the combined measurements of the three satellites provide a comprehensive view of the current systems. The analysis hereof reveals some surprising results concerning the connection between solar wind driver and the resulting ionospheric currents. Specifically, preconditioning of the magnetosphere (history of the interplanetary magnetic field) is seen to play an important role, and in the winther hemisphere, it seems to be harder to drive currents on the nightside than on the dayside.

46 CFR 111.05-11 - Hull return.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Hull return. 111.05-11 Section 111.05-11 Shipping COAST... REQUIREMENTS Equipment Ground, Ground Detection, and Grounded Systems § 111.05-11 Hull return. (a) A vessel's hull must not carry current as a conductor except for the following systems: (1) Impressed current...

U.S. EPA'S STRATEGY FOR GROUND WATER QUALITY MONITORING AT HAZARDOUS WASTE LAND DISPOSAL FACILITIES LOCATED IN KARST TERRANES

EPA Science Inventory

Ground water monitoring of hazardous waste land disposal units by a network of wells is ineffective when located in karstic terranes. The U.S. Environmental Protection Agency (EPA) is currently proposing to modify its current ground water quality monitoring requirement of one upg...

30 CFR 75.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2011 CFR

2011-07-01

... receiving power from ungrounded alternating current power systems. 75.701-1 Section 75.701-1 Mineral... receiving power from ungrounded alternating current power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power...

30 CFR 75.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2010 CFR

2010-07-01

... receiving power from ungrounded alternating current power systems. 75.701-1 Section 75.701-1 Mineral... receiving power from ungrounded alternating current power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power...

The Future of Ground Magnetometer Arrays in Support of Space Weather Monitoring and Research

NASA Astrophysics Data System (ADS)

Engebretson, Mark; Zesta, Eftyhia

2017-11-01

A community workshop was held in Greenbelt, Maryland, on 5-6 May 2016 to discuss recommendations for the future of ground magnetometer array research in space physics. The community reviewed findings contained in the 2016 Geospace Portfolio Review of the Geospace Section of the Division of Atmospheric and Geospace Science of the National Science Foundation and discussed the present state of ground magnetometer arrays and possible pathways for a more optimal, robust, and effective organization and scientific use of these ground arrays. This paper summarizes the report of that workshop to the National Science Foundation (Engebretson & Zesta, as well as conclusions from two follow-up meetings. It describes the current state of U.S.-funded ground magnetometer arrays and summarizes community recommendations for changes in both organizational and funding structures. It also outlines a variety of new and/or augmented regional and global data products and visualizations that can be facilitated by increased collaboration among arrays. Such products will enhance the value of ground-based magnetometer data to the community's effort for understanding of Earth's space environment and space weather effects.

A read-in IC for infrared scene projectors with voltage drop compensation for improved uniformity of emitter current

NASA Astrophysics Data System (ADS)

Cho, Min Ji; Shin, Uisub; Lee, Hee Chul

2017-05-01

This paper proposes a read-in integrated circuit (RIIC) for infrared scene projectors, which compensates for the voltage drops in ground lines in order to improve the uniformity of the emitter current. A current output digital-to-analog converter is utilized to convert digital scene data into scene data currents. The unit cells in the array receive the scene data current and convert it into data voltage, which simultaneously self-adjusts to account for the voltage drop in the ground line in order to generate the desired emitter current independently of variations in the ground voltage. A 32 × 32 RIIC unit cell array was designed and fabricated using a 0.18-μm CMOS process. The experimental results demonstrate that the proposed RIIC can output a maximum emitter current of 150 μA and compensate for a voltage drop in the ground line of up to 500 mV under a 3.3-V supply. The uniformity of the emitter current is significantly improved compared to that of a conventional RIIC.

Education and Public Outreach for the PICASSO-CENA Satellite-Based Research Mission: K-12 Students Use Sun Photometers to Assist Scientists in Validating Atmospheric Data

NASA Astrophysics Data System (ADS)

Robinson, D. Q.

2001-05-01

Hampton University, a historically black university, is leading the Education and Public Outreach (EPO) portion of the PICASSO-CENA satellite-based research mission. Currently scheduled for launch in 2004, PICASSO-CENA will use LIDAR (LIght Detection and Ranging), to study earth's atmosphere. The PICASSO-CENA Outreach program works with scientists, teachers, and students to better understand the effects of clouds and aerosols on earth's atmosphere. This program actively involves students nationwide in NASA research by having them obtain sun photometer measurements from their schools and homes for comparison with data collected by the PICASSO-CENA mission. Students collect data from their classroom ground observations and report the data via the Internet. Scientists will use the data from the PICASSO-CENA research and the student ground-truthing observations to improve predications about climatic change. The two-band passive remote sensing sun photometer is designed for student use as a stand alone instrument to study atmospheric turbidity or in conjunction with satellite data to provide ground-truthing. The instrument will collect measurements of column optical depth from the ground level. These measurements will not only give the students an appreciation for atmospheric turbidity, but will also provide quantitative correlative information to the PICASSO-CENA mission on ground-level optical depth. Student data obtained in this manner will be sufficiently accurate for scientists to use as ground truthing. Thus, students will have the opportunity to be involved with a NASA satellite-based research mission.

Early use of Space Station Freedom for NASA's Microgravity Science and Applications Program

NASA Technical Reports Server (NTRS)

Rhome, Robert C.; O'Malley, Terence F.

1992-01-01

The paper describes microgravity science opportunities inherent to the restructured Space Station and presents a synopsis of the scientific utilization plan for the first two years of ground-tended operations. In the ground-tended utilization mode the Space Station is a large free-flyer providing a continuous microgravity environment unmatched by any other platform within any existing U.S. program. It is pointed out that the importance of this period of early Space Station mixed-mode utilization between crew-tended and ground-tended approaches is of such magnitude that Station-based microgravity science experiments many become benchmarks to the disciplines involved. The traffic model that is currently being pursued is designed to maximize this opportunity for the U.S. microgravity science community.

New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites

NASA Astrophysics Data System (ADS)

Rycroft, Michael J.; Odzimek, Anna; Arnold, Neil F.; Füllekrug, Martin; Kułak, Andrzej; Neubert, Torsten

2007-12-01

Several processes acting below, in and above thunderstorms and in electrified shower clouds drive upward currents which close through the global atmospheric electric circuit. These are all simulated in a novel way using the software package PSpice. A moderate negative cloud-to-ground lightning discharge from the base of a thunderstorm increases the ionospheric potential above the thundercloud by 0.0013%. Assuming the ionosphere to be an equipotential surface, this discharge increases the current flowing in the global circuit and the fair-weather electric field also by 0.0013%. A moderate positive cloud-to-ground lightning discharge from the bottom of a thunderstorm decreases the ionospheric potential by 0.014%. Such a discharge may trigger a sprite, causing the ionospheric potential to decrease by ˜1V. The time scales for the recovery of the ionospheric potential are shown to be ˜250s, which is of the same order as the CR time constant for the global circuit. Knowing the global average rate of lightning discharges, it is found that negative cloud-to-ground discharges increase the ionospheric potential by only ˜4%, and that positive cloud-to-ground discharges reduce it by ˜3%. Thus, overall, lightning contributes only ˜1%—an almost insignificant proportion—to maintaining the high potential of the ionosphere. It is concluded that the net upward current to the ionosphere due to lightning is only ˜20A. Further, it is concluded that conduction and convection currents associated with “batteries” within thunderclouds and electrified shower clouds contribute essentially equally (˜500A each) to maintaining the ionospheric potential.

Magnetic effects of magnetospheric currents at ground and in low orbit

NASA Astrophysics Data System (ADS)

Stolle, C.; Willer, A.; Finlay, C. C.; Olsen, N.

2012-12-01

Since the advent of high precision vector magnetic field observations from satellites in low orbit it has been recognized that magnetospheric currents contribute by about 20nT to the geomagnetic field even during quiet times (when Dst=0nT) (Langel et al., 1980). Comparing spherical harmonic models of the magnetospheric field derived from ground observations with satellite data shows a similar offset. A robust linear fit between these two quantities reveals a slope of about 0.9, indicating that only 90% of the magnetospheric field as monitored on ground is seen by satellites. The intercept of ~20nT is found to diminish with reducing solar activity (as was previously noted by Lühr & Maus, 2010), while the slope is hardly affected. There have been several suggestions for the origin of this systematic difference between ground and space based observations of magnetospheric fields. We compare magnetic residuals of selected observatories with those of CHAMP satellite observations at times of conjunctions, separating the data pairs by criteria including local time and longitude, season, solar and magnetic activity. Obtaining rough estimates of the ionospheric conductivity in this way, we are able to discuss possible ionospheric sources for the observed intercept. Consideration of appropriate ordering in local time, also enables us to test for possible contributions from field aligned currents connecting the ionosphere and the magnetosphere. Langel RA, Mead GD, Lancaster ER, Estes RH, Fabiano EB. 1980. Initial geomagnetic field model from Magsat vector data. Geophys. Res. Lett. 7:793-96 Lühr H, Maus S. 2010. Solar cycle dependence of quiet-time magnetospheric currents and a model of their near-Earth magnetic fields. Earth Planets Space 62:843-48

Ground Based Monitoring of Cloud Activity on Titan

NASA Astrophysics Data System (ADS)

Corlies, Paul; Hayes, Alexander; Rojo, Patricio; Ádámkovics, Máté; Turtle, Elizabeth; Buratti, Bonnie

2014-11-01

We will report on the latest results of an on-going ground based monitoring campaign of Saturn’s moon Titan using the SINFONI (Spectrograph for INtegral Field Observations in the Near Infrared) instrument on the Very Large Telescope (VLT). Presently, much is still unknown about the complex and dynamic hydrologic system of Titan as observations have yet to be made through an entire Titan year (29.7 Earth years). Because of the limited ability to observe Titan with Cassini, a combined ground and spaced-based approach provides a steady cadence of observation throughout the duration of a Titan year. We will present the results of observations to date using the adaptive optics (AO) mode (weather dependent) of SINFONI. We have been regularly observing Titan since April 2014 for the purpose of monitoring and identifying clouds and have also been in collaboration with the Cassini team that has concurrent ISS observations and historical VIMS observations of clouds. Our discussion will focus on the various algorithms and approaches used for cloud identification and analysis. Currently, we are entering into a very interesting time for clouds and Titan hydrology as Saturn moves into north polar summer for the first time since Cassini entered the Saturnian system. The increased insolation that this will bring to the north, where the majority of the liquid methane lakes reside, will give us our first observations of the potentially complex interplay between surface liquid and atmospheric conditions. By carefully monitoring and characterizing clouds (size, optical depth, altitude, etc.) we will also be able to derive constraints that can help to guide and validate GCMs. Since the beginning of our observations, no clouds have been observed through ground based observations, while Cassini has only observed a single cloud event in the north polar region over Ligeia Mare. We will provide an update on the latest results of our cloud monitoring campaign and discuss how this atmospheric inactivity and the frequency and characteristics of future cloud outbursts enhances our current understanding of Titan's hydrologic system.

Temperament Types of Social Studies Teachers.

ERIC Educational Resources Information Center

Dorow, Ernest B.

Temperament type is a key to understanding the classroom behavior of social studies teachers. Current criticisms of strategies employed, dependence on the textbook, fact oriented testing, and the dearth of problem solving in lesson planning are grounded in professional decisions based on temperament preferences. Employing four types of temperament…

14 CFR 91.1023 - Program operating manual requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... manager must prepare and keep current a program operating manual setting forth procedures and policies acceptable to the Administrator. The program manager's management, flight, ground, and maintenance personnel... personnel. (b) Each program manager must maintain at least one copy of the manual at its principal base of...

Advanced Environmental Monitoring Technologies

NASA Technical Reports Server (NTRS)

Jan, Darrell

2004-01-01

Viewgraphs on Advanced Environmental Monitoring Technologies are presented. The topics include: 1) Monitoring & Controlling the Environment; 2) Illustrative Example: Canary 3) Ground-based Commercial Technology; 4) High Capability & Low Mass/Power + Autonomy = Key to Future SpaceFlight; 5) Current Practice: in Flight; 6) Current Practice: Post Flight; 7) Miniature Mass Spectrometer for Planetary Exploration and Long Duration Human Flight; 8) Hardware and Data Acquisition System; 9) 16S rDNA Phylogenetic Tree; and 10) Preview of Porter.

Development of an air ground data exchange concept: Flight deck perspective

NASA Technical Reports Server (NTRS)

Flathers, G. W., II

1987-01-01

The planned modernization of the U.S. National Airspace System (NAS) includes the development and use of a digital data link as a means to exchange information between aircraft and ground-based facilities. This report presents an operationally-oriented concept on how data link could be used for applications related directly to air traffic control. The specific goal is to establish the role that data link could play in the air-ground communications. Due regard is given to the unique characteristics of data link and voice communications, current principles of air traffic control, operational procedures, human factors/man-machine interfaces, and the integration of data link with other air and ground systems. The resulting concept is illustrated in the form of a paper-and-pencil simulation in which data link and voice communications during the course of a hypothetical flight are described.

Multiple beacons for supporting lunar landing navigation

NASA Astrophysics Data System (ADS)

Theil, Stephan; Bora, Leonardo

2018-02-01

The exploration and potential future exploitation of solar system bodies requires technologies for precise and safe landings. Current navigation systems for landing probes are relying on a combination of inertial and optical sensor measurements to determine the current flight state with respect to the target body and the desired landing site. With a future transition from single exploration missions to more frequent first exploration and then exploitation missions, the implementation and operation of these missions changes, since it can be expected that a ground infrastructure on the target body is available in the vicinity of the landing site. In a previous paper, the impact of a single ground-based beacon on the navigation performance was investigated depending on the type of radiometric measurements and on the location of the beacon with respect to the landing site. This paper extends this investigation on options for ground-based multiple beacons supporting the on-board navigation system. It analyzes the impact on the achievable navigation accuracy. For that purpose, the paper introduces briefly the existing navigation architecture based on optical navigation and its extension with radiometric measurements. The same scenario of lunar landing as in the previous paper is simulated. The results are analyzed and discussed. They show a single beacon at a large distance along the landing trajectory and multiple beacons close to the landing site can improve the navigation performance. The results show how large the landing area can be increased where a sufficient navigation performance is achieved using the beacons.

Expansion of Microbial Monitoring Capabilities on the International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Khodadad, Christina L.; Oubre, Cherie; Castro, Victoria; Flint, Stephanie; Melendez, Orlando; Ott, C. Mark; Roman, Monsi

2017-01-01

Microbial monitoring is one of the tools that the National Aeronautics and Space Administration (NASA) uses on the International Space Station (ISS) to help maintain crew health and safety. In combination with regular housekeeping and disinfection when needed, microbial monitoring provides important information to the crew about the quality of the environment. Rotation of astronauts, equipment, and cargo on the ISS can affect the microbial load in the air, surfaces, and water. The current ISS microbial monitoring methods are focused on culture-based enumeration during flight and require a significant amount of crew time as well as long incubation periods of up to 5 days there by proliferating potential pathogens. In addition, the samples require return to Earth for complete identification of the microorganisms cultivated. Although the current approach assess the quality of the ISS environment, molecular technology offers faster turn-around of information particularly beneficial in an off-nominal situation. In 2011, subject matter experts from industry and academia recommended implementation of molecular-based technologies such as quantitative real-time polymerase chain reaction (qPCR) for evaluation to replace current, culture-based technologies. The RAZOR EX (BioFire Defense, Inc, Salt Lake City, UT) a ruggedized, compact, COTS (commercial off the shelf) qPCR instrument was tested, evaluated and selected in the 2 X 2015 JSC rapid flight hardware demonstration initiative as part of the Water Monitoring Suite. RAZOR EX was launched to ISS on SpaceX-9 in July 2016 to evaluate the precision and accuracy of the hardware by testing various concentrations of DNA in microgravity compared to ground controls. Flight testing was completed between September 2016 and March 2017. Data presented will detail the hardware performance of flight testing results compared to ground controls. Future goals include additional operational ground-based testing and assay development to determine if this technology can meet spaceflight microbial monitoring requirements.

Benefit of Modeling the Observation Error in a Data Assimilation Framework Using Vegetation Information Obtained From Passive Based Microwave Data

NASA Technical Reports Server (NTRS)

Bolten, John D.; Mladenova, Iliana E.; Crow, Wade; De Jeu, Richard

2016-01-01

A primary operational goal of the United States Department of Agriculture (USDA) is to improve foreign market access for U.S. agricultural products. A large fraction of this crop condition assessment is based on satellite imagery and ground data analysis. The baseline soil moisture estimates that are currently used for this analysis are based on output from the modified Palmer two-layer soil moisture model, updated to assimilate near-real time observations derived from the Soil Moisture Ocean Salinity (SMOS) satellite. The current data assimilation system is based on a 1-D Ensemble Kalman Filter approach, where the observation error is modeled as a function of vegetation density. This allows for offsetting errors in the soil moisture retrievals. The observation error is currently adjusted using Normalized Difference Vegetation Index (NDVI) climatology. In this paper we explore the possibility of utilizing microwave-based vegetation optical depth instead.

Modular Extended-Stay HyperGravity Facility Design Concept: An Artificial-Gravity Space-Settlement Ground Analogue

NASA Technical Reports Server (NTRS)

Dorais, Gregory A.

2015-01-01

This document defines the design concept for a ground-based, extended-stay hypergravity facility as a precursor for space-based artificial-gravity facilities that extend the permanent presence of both human and non-human life beyond Earth in artificial-gravity settlements. Since the Earth's current human population is stressing the environment and the resources off-Earth are relatively unlimited, by as soon as 2040 more than one thousand people could be living in Earthorbiting artificial-gravity habitats. Eventually, the majority of humanity may live in artificialgravity habitats throughout this solar system as well as others, but little is known about the longterm (multi-generational) effects of artificial-gravity habitats on people, animals, and plants. In order to extend life permanently beyond Earth, it would be useful to create an orbiting space facility that generates 1g as well as other gravity levels to rigorously address the numerous challenges of such an endeavor. Before doing so, developing a ground-based artificial-gravity facility is a reasonable next step. Just as the International Space Station is a microgravity research facility, at a small fraction of the cost and risk a ground-based artificial-gravity facility can begin to address a wide-variety of the artificial-gravity life-science questions and engineering challenges requiring long-term research to enable people, animals, and plants to live off-Earth indefinitely.

Pilot and Controller Evaluations of Separation Function Allocation in Air Traffic Management

NASA Technical Reports Server (NTRS)

Wing, David; Prevot, Thomas; Morey, Susan; Lewis, Timothy; Martin, Lynne; Johnson, Sally; Cabrall, Christopher; Como, Sean; Homola, Jeffrey; Sheth-Chandra, Manasi;

A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging

NASA Astrophysics Data System (ADS)

Martin, Spencer; Brophy, Mark; Palma, David; Louie, Alexander V.; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Barron, John L.; Beauchemin, Steven S.; Rodrigues, George; Gaede, Stewart

2015-02-01

This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51  ±  1.92) to (97.27  ±  0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development.

A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging.

PubMed

Martin, Spencer; Brophy, Mark; Palma, David; Louie, Alexander V; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Barron, John L; Beauchemin, Steven S; Rodrigues, George; Gaede, Stewart

2015-02-21

This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51  ±  1.92) to (97.27  ±  0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development.

Versatile current-mode universal biquadratic filter using DO-CCIIs

NASA Astrophysics Data System (ADS)

Chen, Hua-Pin

2013-07-01

In this article, a new three-input and three-output versatile current-mode universal biquadratic filter is proposed. The circuit employs three dual-output current conveyors (DO-CCIIs) as active elements together with three grounded resistors and two grounded capacitors. The proposed configuration exhibits low-input impedance and high-output impedance which is important for easy cascading in the current-mode operations. It can be used as either a single-input and three-output or three-input and two-output circuit. In the operation of single-input and three-output circuit, the lowpass, bandpass and bandreject can be realised simultaneously, while the highpass filtering response can be easily obtained by connecting appropriated output current directly without using addition stages. In the operation of three-input and two-output circuit, all five generic filtering functions can be easily realised by selecting different three input current signals. The filter permits orthogonal controllability of the quality factor and resonance angular frequency, and no component matching conditions or inverting-type input current signals are imposed. All the passive and active sensitivities are low. HSPICE simulation results based on using TSMC 0.18 µm 1P6M CMOS process technology and supply voltages ±0.9 V to verify the theoretical analysis.

Evaluation of ground motion scaling methods for analysis of structural systems

USGS Publications Warehouse

O'Donnell, A. P.; Beltsar, O.A.; Kurama, Y.C.; Kalkan, E.; Taflanidis, A.A.

2011-01-01

Ground motion selection and scaling comprises undoubtedly the most important component of any seismic risk assessment study that involves time-history analysis. Ironically, this is also the single parameter with the least guidance provided in current building codes, resulting in the use of mostly subjective choices in design. The relevant research to date has been primarily on single-degree-of-freedom systems, with only a few studies using multi-degree-of-freedom systems. Furthermore, the previous research is based solely on numerical simulations with no experimental data available for the validation of the results. By contrast, the research effort described in this paper focuses on an experimental evaluation of selected ground motion scaling methods based on small-scale shake-table experiments of re-configurable linearelastic and nonlinear multi-story building frame structure models. Ultimately, the experimental results will lead to the development of guidelines and procedures to achieve reliable demand estimates from nonlinear response history analysis in seismic design. In this paper, an overview of this research effort is discussed and preliminary results based on linear-elastic dynamic response are presented. ?? ASCE 2011.

Engineering management consideration for an integrated aeronautical mobile satellite service

NASA Astrophysics Data System (ADS)

Belcher, John M.

In order to meet local air traffic control terminal requirements as well as national and transborder requirements, countries have developed communications, navigation, and surveillance (CNS) systems having little systems integration and a solely ground-based solution to air traffic control problems. It is believed that the application of satellite technology is the only currently viable solution that will enable international civil aviation to overcome the shortcomings of the presently available CNS systems. If properly implemented, available satellite system technology integrated with avionics and ground based capabilities, can be used to meet new global aviation demands. A clear transition plan has to be implemented so as to ensure continuity of service, recognize user-borne costs, and satisfy institutional and national objectives in the progress toward a universal air traffic management (ATM) system. ATM systems design should rely on a modular approach for flexibility and upgrading. An aeronautical mobile satellite service is intended to provide a worldwide satellite data link and direct air/ground voice communication. Institutional and financial roadblocks for implemetation of a global based approach will likely be far greater than technical constraints.

Refueling Strategies for a Team of Cooperating AUVs

DTIC Science & Technology

2011-01-01

manager, and thus the constraint a centrally managed underwater network imposes on the mission. Task management utilizing Robust Decentralized Task ...the computational complexity. A bid based approach to task management has also been studied as a possible means of decentralization of group task ...currently performing another task . In [18], ground robots perform distributed task allocation using the ASyMTRy-D algorithm, which is based on CNP

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; Lynch, Kristina A.; Fernandes, Philip A.; Aruliah, Anasuya L.; Engebretson, Mark J.; Moen, Jøran I.; Oksavik, Kjellmar; Yahnin, Alexander G.; Yeoman, Timothy K.

2017-05-01

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements with corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.

Methods for locating ground faults and insulation degradation condition in energy conversion systems

DOEpatents

Agamy, Mohamed; Elasser, Ahmed; Galbraith, Anthony William; Harfman Todorovic, Maja

2015-08-11

Methods for determining a ground fault or insulation degradation condition within energy conversion systems are described. A method for determining a ground fault within an energy conversion system may include, in part, a comparison of baseline waveform of differential current to a waveform of differential current during operation for a plurality of DC current carrying conductors in an energy conversion system. A method for determining insulation degradation within an energy conversion system may include, in part, a comparison of baseline frequency spectra of differential current to a frequency spectra of differential current transient at start-up for a plurality of DC current carrying conductors in an energy conversion system. In one embodiment, the energy conversion system may be a photovoltaic system.

HVDC Ground Electrodes - a Source of Geophysical Data

NASA Astrophysics Data System (ADS)

Freire, P. F.; Pereira, S. Y.

2015-12-01

The HVDC electrode is a component of a High Voltage Direct Current energy transmission system, and is designed to inject into the ground continuous currents up to 3500 A. The typical HVDC ground electrode is a ring of vertical conductors, 1 km wide, buried a few tens of meters.The design of a HVDC electrode is based on extensive geological, geotechnical and geophysical surveys. Geophysical data are usually electrical (VES) and electromagnetic (TEM/MT) acquisitions, for the modeling of the shallow, near-surface and deep layers of the crust. This survey aims, first, the electrode site selection, and then, at the selected site, this data is combined into a single apparent resistivity curve, which is inverted, allowing for the determination of the layered geoelectric crust model. The injection of electrical continuous current in the electrode is then simulated, with the geoelectric crust model, for the determination of the soil surface potential profile (which is usually asymmetric for different directions, due to non-1D geoelectric models).For the commissioning of a HVDC electrode, field measurements are done, such as electrode grounding resistance, soil surface potentials and metal-to-soil potentials at specific structures (buried pipelines, for instance).The geophysical data acquired during the design phase is a set of data completely independent from the electrical data acquired during the electrode commissioning phase, and both are correlated by the geoelectric model. It happens, therefore, that the geoelectric model can be calibrated based on the electrical data, with the correction of static shifts and other adjustments.This paper suggests that the commissioning of HVDC systems should be associated to a research & development program, with a university or foundation. The idea is to enjoy the opportunity of a more complete field survey, with the acquisition of a wide set of data for a better geological characterization of the area where the electrode was built.

Combining points and lines in rectifying satellite images

NASA Astrophysics Data System (ADS)

Elaksher, Ahmed F.

2017-09-01

The quick advance in remote sensing technologies established the potential to gather accurate and reliable information about the Earth surface using high resolution satellite images. Remote sensing satellite images of less than one-meter pixel size are currently used in large-scale mapping. Rigorous photogrammetric equations are usually used to describe the relationship between the image coordinates and ground coordinates. These equations require the knowledge of the exterior and interior orientation parameters of the image that might not be available. On the other hand, the parallel projection transformation could be used to represent the mathematical relationship between the image-space and objectspace coordinate systems and provides the required accuracy for large-scale mapping using fewer ground control features. This article investigates the differences between point-based and line-based parallel projection transformation models in rectifying satellite images with different resolutions. The point-based parallel projection transformation model and its extended form are presented and the corresponding line-based forms are developed. Results showed that the RMS computed using the point- or line-based transformation models are equivalent and satisfy the requirement for large-scale mapping. The differences between the transformation parameters computed using the point- and line-based transformation models are insignificant. The results showed high correlation between the differences in the ground elevation and the RMS.

Enhanced Weather Radar (EWxR) System

NASA Technical Reports Server (NTRS)

Kronfeld, Kevin M. (Technical Monitor)

2003-01-01

An airborne weather radar system, the Enhanced Weather Radar (EWxR), with enhanced on-board weather radar data processing was developed and tested. The system features additional weather data that is uplinked from ground-based sources, specialized data processing, and limited automatic radar control to search for hazardous weather. National Weather Service (NWS) ground-based Next Generation Radar (NEXRAD) information is used by the EWxR system to augment the on-board weather radar information. The system will simultaneously display NEXRAD and on-board weather radar information in a split-view format. The on-board weather radar includes an automated or hands-free storm-finding feature that optimizes the radar returns by automatically adjusting the tilt and range settings for the current altitude above the terrain and searches for storm cells near the atmospheric 0-degree isotherm. A rule-based decision aid was developed to automatically characterize cells as hazardous, possibly-hazardous, or non-hazardous based upon attributes of that cell. Cell attributes are determined based on data from the on-board radar and from ground-based radars. A flight path impact prediction algorithm was developed to help pilots to avoid hazardous weather along their flight plan and their mission. During development the system was tested on the NASA B757 aircraft and final tests were conducted on the Rockwell Collins Sabreliner.

Human Factors Considerations for Performance-Based Navigation

NASA Technical Reports Server (NTRS)

Barhydt, Richard; Adams, Catherine A.

2006-01-01

A transition toward a performance-based navigation system is currently underway in both the United States and around the world. Performance-based navigation incorporates Area Navigation (RNAV) and Required Navigation Performance (RNP) procedures that do not rely on the location of ground-based navigation aids. These procedures offer significant benefits to both operators and air traffic managers. Under sponsorship from the Federal Aviation Administration (FAA), the National Aeronautics and Space Administration (NASA) has undertaken a project to document human factors issues that have emerged during RNAV and RNP operations and propose areas for further consideration. Issues were found to include aspects of air traffic control and airline procedures, aircraft systems, and procedure design. Major findings suggest the need for human factors-specific instrument procedure design guidelines. Ongoing industry and government activities to address air-ground communication terminology, procedure design improvements, and chart-database commonality are strongly encouraged.

Health assessment for Mather Air Force Base, California, Region 9. CERCLIS No. CA8570024143. Preliminary report

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

Not Available

Mather Air Force Base (MAFB), California is east of Sacramento, California. The Air Command and Warning site is the only site within the Base currently on the National Priorities List. Ground water was the only medium sampled; it was found to be contaminated with TCE (0.9 to 22.0 micro g/L), tetrachloroethylene (0.6 to 3.6 micro g/L), vinyl chloride (0.7 to 9.9 micro g/L), dichloroethane (2.5 micro g/L), and 1,4-dichlorobenzene (3.3 micro g/L). The health threats posed by contaminants attributable to MAFB have not been evaluated. Ground water and sediment contamination on the base have been confirmed. The site is ofmore » potential health concern because of the potential risk to human health resulting from possible exposure to hazardous substances at concentrations that may result in adverse health effects.« less

The North Alabama Lightning Warning Product

NASA Technical Reports Server (NTRS)

Buechler, Dennis E.; Blakeslee, R. J.; Stano, G. T.

2009-01-01

The North Alabama Lightning Mapping Array NALMA has been collecting total lightning data on storms in the Tennessee Valley region since 2001. Forecasters from nearby National Weather Service (NWS) offices have been ingesting this data for display with other AWIPS products. The current lightning product used by the offices is the lightning source density plot. The new product provides a probabalistic, short-term, graphical forecast of the probability of lightning activity occurring at 5 min intervals over the next 30 minutes . One of the uses of the current lightning source density product by the Huntsville National Weather Service Office is to identify areas of potential for cloud-to-ground flashes based on where LMA total lightning is occurring. This product quantifies that observation. The Lightning Warning Product is derived from total lightning observations from the Washington, D.C. (DCLMA) and North Alabama Lightning Mapping Arrays and cloud-to-ground lightning flashes detected by the National Lightning Detection Network (NLDN). Probability predictions are provided for both intracloud and cloud-to-ground flashes. The gridded product can be displayed on AWIPS workstations in a manner similar to that of the lightning source density product.

Standardizing Interaction Design Education

ERIC Educational Resources Information Center

Thomassen, Aukje; Ozcan, Oguzhan

2010-01-01

The objective of this paper is to which extend the didactic format of studio-based group-work is applicable for creating a common-ground for Interaction Design Education in European Perspective. The current debate on design education shows us a landscape of different initiatives. So far difficulties have arisen in the area of accreditation and…

Equipping Preservice Elementary Teachers for Data Use in the Classroom

ERIC Educational Resources Information Center

Reeves, Todd D.

2017-01-01

Current preservice teacher education practice related to data use has been deemed inadequate, in that it is unevenly distributed and often superficial. In response, this article describes a course-based classroom assessment data-literacy experience for preservice elementary teachers. Grounded in extant theory and research concerning data literacy…

Euthanasia and Mental Retardation: Suggesting the Unthinkable.

ERIC Educational Resources Information Center

Hollander, Russell

1989-01-01

The article examines current opinions toward euthanasia of persons with mental retardation in light of the history of public and professional attitudes. It also discusses the rejection of euthanasia on moral and religious grounds, and notes the use of lifelong incarceration, based on eugenics principles, to accomplish similar ends. (DB)

The Atacama Large Millimeter/Submillimeter Array (ALMA) - A Successful Three-Way International Partnership Without a Majority Stakeholder

NASA Astrophysics Data System (ADS)

Vanden Bout, Paul A.

2013-04-01

The Atacama Millimeter/Submillimeter Array (ALMA) is the largest ground-based astronomical facility built to date. It's size and challenging site required an international effort. This talk presents the partnership structure, management challenges, current status, and examples of early scientific successes.

Education: Opportunity through Learning. USAID Education Strategy, 2011-2015

ERIC Educational Resources Information Center

US Agency for International Development, 2011

2011-01-01

In late 2010, the U.S. Agency for International Development (USAID) Administrator Rajiv Shah commissioned a new Agency-wide Education Strategy to ensure that USAID's global education investments would be informed by recent Presidential policy guidance; grounded in the most current evidence-based analysis of educational effectiveness; and aimed at…

Migration monitoring with automated technology

Treesearch

Rhonda L. Millikin

2005-01-01

Automated technology can supplement ground-based methods of migration monitoring by providing: (1) unbiased and automated sampling; (2) independent validation of current methods; (3) a larger sample area for landscape-level analysis of habitat selection for stopover, and (4) an opportunity to study flight behavior. In particular, radar-acoustic sensor fusion can...

Reusable Autonomy

NASA Technical Reports Server (NTRS)

Truszkowski, Walt; Obenschain, Arthur F. (Technical Monitor)

2002-01-01

Currently, spacecraft ground systems have a well defined and somewhat standard architecture and operations concept. Based on domain analysis studies of various control centers conducted over the years it is clear that ground systems have core capabilities and functionality that are common across all ground systems. This observation alone supports the realization of reuse. Additionally, spacecraft ground systems are increasing in their ability to do things autonomously. They are being engineered using advanced expert systems technology to provide automated support for operators. A clearer understanding of the possible roles of agent technology is advancing the prospects of greater autonomy for these systems. Many of their functional and management tasks are or could be supported by applied agent technology, the dynamics of the ground system's infrastructure could be monitored by agents, there are intelligent agent-based approaches to user-interfaces, etc. The premise of this paper is that the concepts associated with software reuse, applicable in consideration of classically-engineered ground systems, can be updated to address their application in highly agent-based realizations of future ground systems. As a somewhat simplified example consider the following situation, involving human agents in a ground system context. Let Group A of controllers be working on Mission X. They are responsible for the command, control and health and safety of the Mission X spacecraft. Let us suppose that mission X successfully completes it mission and is turned off. Group A could be dispersed or perhaps move to another Mission Y. In this case there would be reuse of the human agents from Mission X to Mission Y. The Group A agents perform their well-understood functions in a somewhat but related context. There will be a learning or familiarization process that the group A agents go through to make the new context, determined by the new Mission Y, understood. This simplified scenario highlights some of the major issues that need to be addressed when considering the situation where Group A is composed of software-based agents (not their human counterparts) and they migrate from one mission support system to another. This paper will address: - definition of an agent architecture appropriate to support reuse; - identification of non-mission-specific agent capabilities required; - appropriate knowledge representation schemes for mission-specific knowledge; - agent interface with mission-specific knowledge (a type of Learning); development of a fully-operational group of cooperative software agents for ground system support; architecture and operation of a repository of reusable agents that could be the source of intelligent components for realizing an autonomous (or nearly autonomous) agent-based ground system, and an agent-based approach to repository management and operation (an intelligent interface for human use of the repository in a ground-system development activity).

Development of an Airborne Micropulse Water Vapor DIAL

NASA Astrophysics Data System (ADS)

Nehrir, A. R.; Ismail, S.

2012-12-01

Water vapor plays a key role in many atmospheric processes affecting both weather and climate. Airborne measurements of tropospheric water vapor profiles have been a longstanding observational need to not only the active remote sensing community but also to the meteorological, weather forecasting, and climate/radiation science communities. Microscale measurements of tropospheric water vapor are important for enhancing near term meteorological forecasting capabilities while mesoscale and synopticscale measurements can lead to an enhanced understanding of the complex coupled feedback mechanisms between water vapor, temperature, aerosols, and clouds. To realize tropospheric measurements of water vapor profiles over the microscale-synopticscale areas of meteorological interest, a compact and cost effective airborne micropulse differential absorption lidar (DIAL) is being investigated using newly emerging semiconductor based laser technology. Ground based micropulse DIAL (MPD) measurements of tropospheric water vapor and aerosol profiles up to 6 km and 15 km, respectively, have been previously demonstrated using an all semiconductor based laser transmitter. The DIAL transmitter utilizes a master oscillator power amplifier (MOPA) configuration where two semiconductor seed lasers are used to seed a single pass traveling wave tapered semiconductor optical amplifier (TSOA), producing up to 7μJ pulse energies over a 1 μs pulse duration at a 10 kHz pulse repetition frequency (PRF). Intercomparisons between the ground based instrument measurements and radiosonde profiles demonstrating the MPD performance under varying atmospheric conditions will be presented. Work is currently ongoing to expand upon the ground based MPD concept and to develop a compact and cost effective system capable of deployment on a mid-low altitude aircraft such as the NASA Langley B200 King Air. Initial lab experiments show that a two-three fold increase in the laser energy compared to the ground based instrument is achievable via overdriven current pulses to the TSOA gain medium while maintaining a 1μs and 10 kHz pulse width and PRF, respectively. The increase in the laser transmitter pulse energy will allow for nighttime and daytime water vapor profile retrievals from an airborne platform operating at an 8 km altitude with 2-5 minute integration periods. Results from a numerical model demonstrating the performance of an airborne DIAL system with the mentioned transmitter enhancements will be presented and compared against the existing ground based instrument performance. Furthermore, results from laboratory experiments demonstrating the laser transmitter performance including maximum extractable energy, energy stability, and spectral purity will also be presented.

Aerial Prefeeding Followed by Ground Based Toxic Baiting for More Efficient and Acceptable Poisoning of Invasive Small Mammalian Pests

PubMed Central

Morgan, David; Warburton, Bruce; Nugent, Graham

2015-01-01

Introduced brushtail possums (Trichosurus vulpecula) and rat species (Rattus spp.) are major vertebrate pests in New Zealand, with impacts on conservation and agriculture being managed largely through poisoning operations. Aerial distribution of baits containing sodium fluoroacetate (1080) has been refined to maximise cost effectiveness and minimise environmental impact, but this method is strongly opposed by some as it is perceived as being indiscriminate. Although ground based control enables precise placement of baits, operations are often more than twice as costly as aerial control, mainly due to the high labour costs. We investigated a new approach to ground based control that combined aerial distribution of non-toxic ‘prefeed’ baits followed by sparse distribution of toxic baits at regular intervals along the GPS tracked prefeeding flight paths. This approach was tested in two field trials in which both 1080 baits and cholecalciferol baits were used in separate areas. Effectiveness of the approach, assessed primarily using ‘chewcards’, was compared with that of scheduled aerial 1080 operations that were conducted in outlying areas of both trials. Contractors carrying out ground based control were able to follow the GPS tracks of aerial prefeeding flight lines very accurately, and with 1080 baits achieved very high levels of kill of possums and rats similar to those achieved by aerial 1080 baiting. Cholecalciferol was less effective in the first trial, but by doubling the amount of cholecalciferol bait used in the second trial, few possums or rats survived. By measuring the time taken to complete ground baiting from GPS tracks, we predicted that the method (using 1080 baits) would be similarly cost effective to aerial 1080 operations for controlling possums and rats, and considerably less expensive than typical current costs of ground based control. The main limitations to the use of the method will be access to, and size of, the operational site, along with topography and vegetation density. PMID:26218095

Retooling Predictive Relations for non-volatile PM by Comparison to Measurements

NASA Astrophysics Data System (ADS)

Vander Wal, R. L.; Abrahamson, J. P.

2015-12-01

Non-volatile particulate matter (nvPM) emissions from jet aircraft at cruise altitude are of particular interest for climate and atmospheric processes but are difficult to measure and are normally approximated. To provide such inventory estimates the present approach is to use measured, ground-based values with scaling to cruise (engine operating) conditions. Several points are raised by this approach. First is what ground based values to use. Empirical and semi-empirical approaches, such as the revised first order approximation (FOA3) and formation-oxidation (FOX) methods, each with embedded assumptions are available to calculate a ground-based black carbon concentration, CBC. Second is the scaling relation that can depend upon the ratios of fuel-air equivalence, pressure, and combustor flame temperature. We are using measured ground-based values to evaluate the accuracy of present methods towards developing alternative methods for CBCby smoke number or via a semi-empirical kinetic method for the specific engine, CFM56-2C, representative of a rich-dome style combustor, and as one of the most prevalent engine families in commercial use. Applying scaling relations to measured ground based values and comparison to measurements at cruise evaluates the accuracy of current scaling formalism. In partnership with GE Aviation, performing engine cycle deck calculations enables critical comparison between estimated or predicted thermodynamic parameters and true (engine) operational values for the CFM56-2C engine. Such specific comparisons allow tracing differences between predictive estimates for, and measurements of nvPM to their origin - as either divergence of input parameters or in the functional form of the predictive relations. Such insights will lead to development of new predictive tools for jet aircraft nvPM emissions. Such validated relations can then be extended to alternative fuels with confidence in operational thermodynamic values and functional form. Comparisons will then be made between these new predictive relationships and measurements of nvPM from alternative fuels using ground and cruise data - as collected during NASA-led AAFEX and ACCESS field campaigns, respectively.

Science with the Advanced Gamma Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Coppi, Paolo

2009-05-01

We present the scientific drivers for the Advanced Gamma Ray Imaging System (AGIS), a concept for the next-generation ground- based gamma-ray experiment, comprised of an array of ˜100 imaging atmospheric Cherenkov telescopes. Design requirements for AGIS include achieving a sensitivity an order of magnitude better than the current generation of space or ground-based instruments in the energy range of 40 GeV to ˜100 TeV. We present here an overview of the scientific goals of AGIS, including the prospects for understanding VHE phenomena in the vicinity of accreting black holes, particle acceleration in a variety of astrophysical environments, indirect detection of dark matter, study of cosmological background radiation fields, and particle physics beyond the standard model.

Electrical measurements in the atmosphere and the Ionosphere over an active thunderstorm. II - Direct current electric fields and conductivity

NASA Technical Reports Server (NTRS)

Holzworth, R. H.; Kelley, M. C.; Siefring, C. L.; Hale, L. C.; Mitchell, J. D.

1985-01-01

On August 9, 1981, a series of three rockets was launched over an air mass thunderstorm off the eastern seaboard of Virginia while simultaneous stratospheric and ground-based electric field measurements were made. The conductivity was substantially lower at most altitudes than the conductivity profiles used by theoretical models. Direct current electric fields over 80 mV/m were measured as far away as 96 km from the storm in the stratosphere at 23 km altitude. No dc electric fields above 75 km altitude could be identified with the thunderstorm, in agreement with theory. However, vertical current densities over 120 pA/sq m were seen well above the classical 'electrosphere' (at 50 or 60 km). Frequent dc shifts in the electric field following lightning transients were seen by both balloon and rocket payloads. These dc shifts are clearly identifiable with either cloud-to-ground (increases) or intercloud (decreases) lightning flashes.

Enhanced Research Opportunity to Study the Atmospheric Forcing by High-Energy Particle Precipitation at High Latitudes: Emerging New Satellite Data and the new Ground-Based Observations in Northern Scandinavia, including the EISCAT_3D Incoherent Scatter Facility.

NASA Astrophysics Data System (ADS)

Turunen, E. S.; Ulich, T.; Kero, A.; Tero, R.; Verronen, P. T.; Norberg, J.; Miyoshi, Y.; Oyama, S. I.; Saito, S.; Hosokawa, K.; Ogawa, Y.

2017-12-01

Recent observational and model results on the particle precipitation as source of atmospheric variability challenge us to implement better and continuously monitoring observational infrastructure for middle and upper atmospheric research. An example is the effect of high-energy electron precipitation during pulsating aurora on mesospheric ozone, the concentration of which may be reduced by several tens of percent, similarily as during some solar proton events, which are known to occur more rarely than pulsating aurora. So far the Assessment Reports by the Intergovernmental Panel on Climate Change did not include explicitely the particle forcing of middle and upper atmosphere in their climate model scenarios. This will appear for the first time in the upcoming climate simulations. We review recent results related to atmospheric forcing by particle precipitation via effects on chemical composition. We also show the research potential of new ground-based radio measurement techniques, such as spectral riometry and incoherent scatter by new phased-array radars, such as EISCAT_3D, which will be a volumetric, 3- dimensionally imaging radar, distributed in Norway, Sweden, and Finland. It is expected to be operational from 2020 onwards, surpassing all the current IS radars of the world in technology. It will be able to produce continuous information of ionospheric plasma parameters in a volume, including 3D-vector plasma velocities. For the first time we will be able to map the 3D electric currents in ionosphere, as well as we will have continuous vector wind measurements in mesosphere. The geographical area covered by the EISCAT_3D measurements can be expanded by suitably selected other continuous observations, such as optical and satellite tomography networks. A new 100 Hz all-sky camera network was recently installed in Northern Scandinavia in order to support the Japanese Arase satellite mission. In near future the ground-based measurement network will also include new mesospheric ozone observations and a north-south chain of spectral riometers in Finland. New space missions will gain from this emerging enhancement of ground-based observations. Possibly essential new data could be provided by polar orbiting cubesats for which scientific level instrumentation is currently being developed.

Prediction Accuracy of Error Rates for MPTB Space Experiment

NASA Technical Reports Server (NTRS)

Buchner, S. P.; Campbell, A. B.; Davis, D.; McMorrow, D.; Petersen, E. L.; Stassinopoulos, E. G.; Ritter, J. C.

1998-01-01

This paper addresses the accuracy of radiation-induced upset-rate predictions in space using the results of ground-based measurements together with standard environmental and device models. The study is focused on two part types - 16 Mb NEC DRAM's (UPD4216) and 1 Kb SRAM's (AMD93L422) - both of which are currently in space on board the Microelectronics and Photonics Test Bed (MPTB). To date, ground-based measurements of proton-induced single event upset (SEM cross sections as a function of energy have been obtained and combined with models of the proton environment to predict proton-induced error rates in space. The role played by uncertainties in the environmental models will be determined by comparing the modeled radiation environment with the actual environment measured aboard MPTB. Heavy-ion induced upsets have also been obtained from MPTB and will be compared with the "predicted" error rate following ground testing that will be done in the near future. These results should help identify sources of uncertainty in predictions of SEU rates in space.

Propagation of current pulses with an amplitude of up to 85 kA in soil over distances of several tens of meters

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

Smirnov, V. P.; Fortov, V. E.; Bykov, Yu. A.

Conditions for the propagation in soil of current pulses with an amplitude of up to 85 kA and temporal characteristics typical of a lightning stroke are studied with the help of a specially designed mobile test complex on the basis of a 4-MJ capacitive energy storage with an output voltage of up to 2 MV. In contrast to the conventional opinion that the ionization processes in highly conductive soils are weakly pronounced, a dramatic reduction in the grounding resistance at a resistivity of about 100 Ω m and currents above 10 kA was observed. A time interval in which themore » grounding resistance is determined by the skin effect in soil is revealed. It is shown that the grounding resistance continues to decrease behind the front of the current pulse due to the continuous growth of spark channels in soil. Time variations in the grounding resistance cannot be related to the formation of a continuous ionization zone near the grounding electrodes and are explained only by the simultaneous growth of several long spark channels extending from the grounding device.« less

A Study on Effect of Concrete Foundations on Resistance and Surface Potentials of Gas Insulated Substation Grounding Systems

NASA Astrophysics Data System (ADS)

Rao, Mandava Mohana

2017-10-01

Ground resistance of high voltage substations must be as low as possible for safe grounding of their equipment both during normal and fault conditions. However, in gas insulated substations (GIS), even though resistance is low, it does not ensure the step and touch potentials of the grounding system within permissible levels. In the present study, an analytical model has been developed to calculate ground resistance, step and touch potentials of a grounding system used for GIS. Different models have been proposed for the evaluation of number of grounding rods to be inserted in to the ground. The effect of concrete foundations on above performance parameters has been analyzed by considering various fault currents, soil/earth resistivities and number of grounding rods. Finally, design optimization of GIS grounding system has been reported for fault currents in the order of 63 kA located in earth resistivity of 100Ω-m and above.

Analysis of the charge exchange between the human body and ground: evaluation of "earthing" from an electrical perspective.

PubMed

Chamberlin, Kent; Smith, Wayne; Chirgwin, Christopher; Appasani, Seshank; Rioux, Paul

2014-12-01

The purpose of this study was to investigate "earthing" from an electrical perspective through measurement and analysis of the naturally occurring electron flow between the human body or a control and ground as this relates to the magnitude of the charge exchange, the relationship between the charge exchange and body functions (respiration and heart rate), and the detection of other information that might be contained in the charge exchange. Sensitive, low-noise instrumentation was designed and fabricated to measure low-level current flow at low frequencies. This instrumentation was used to record current flow between human subjects or a control and ground, and these measurements were performed approximately 40 times under varied circumstances. The results of these measurements were analyzed to determine if information was contained in the current exchange. The currents flowing between the human body and ground were small (nanoamperes), and they correlated with subject motion. There did not appear to be any information contained in this exchange except for information about subject motion. This study showed that currents flow between the environment (earth) and a grounded human body; however, these currents are small (nanoamperes) and do not appear to contain information other than information about subject motion.

Analysis of the Charge Exchange Between the Human Body and Ground: Evaluation of “Earthing” From an Electrical Perspective

PubMed Central

Chamberlin, Kent; Smith, Wayne; Chirgwin, Christopher; Appasani, Seshank; Rioux, Paul

2014-01-01

Objective The purpose of this study was to investigate “earthing” from an electrical perspective through measurement and analysis of the naturally occurring electron flow between the human body or a control and ground as this relates to the magnitude of the charge exchange, the relationship between the charge exchange and body functions (respiration and heart rate), and the detection of other information that might be contained in the charge exchange. Methods Sensitive, low-noise instrumentation was designed and fabricated to measure low-level current flow at low frequencies. This instrumentation was used to record current flow between human subjects or a control and ground, and these measurements were performed approximately 40 times under varied circumstances. The results of these measurements were analyzed to determine if information was contained in the current exchange. Results The currents flowing between the human body and ground were small (nanoamperes), and they correlated with subject motion. There did not appear to be any information contained in this exchange except for information about subject motion. Conclusions This study showed that currents flow between the environment (earth) and a grounded human body; however, these currents are small (nanoamperes) and do not appear to contain information other than information about subject motion. PMID:25435837

Vibrationally resolved photoelectron spectroscopy of electronic excited states of DNA bases: application to the ã state of thymine cation.

PubMed

Hochlaf, Majdi; Pan, Yi; Lau, Kai-Chung; Majdi, Youssef; Poisson, Lionel; Garcia, Gustavo A; Nahon, Laurent; Al Mogren, Muneerah Mogren; Schwell, Martin

2015-02-19

For fully understanding the light-molecule interaction dynamics at short time scales, recent theoretical and experimental studies proved the importance of accurate characterizations not only of the ground (D0) but also of the electronic excited states (e.g., D1) of molecules. While ground state investigations are currently straightforward, those of electronic excited states are not. Here, we characterized the à electronic state of ionic thymine (T(+)) DNA base using explicitly correlated coupled cluster ab initio methods and state-of-the-art synchrotron-based electron/ion coincidence techniques. The experimental spectrum is composed of rich and long vibrational progressions corresponding to the population of the low frequency modes of T(+)(Ã). This work challenges previous numerous works carried out on DNA bases using common synchrotron and VUV-based photoelectron spectroscopies. We provide hence a powerful theoretical and experimental framework to study the electronic structure of ionized DNA bases that could be generalized to other medium-sized biologically relevant systems.

User manual for the NTS ground motion data base retrieval program: ntsgm

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

App, F.N.; Tunnell, T.W.

1994-05-01

The NTS (Nevada Test Site) Ground Motion Data Base is composed of strong motion data recorded during the normal execution of the US underground test program. It contains surface, subsurface, and structure motion data as digitized waveforms. Currently the data base contains information from 148 underground explosions. This represents about 4,200 measurements and nearly 12,000 individual digitized waveforms. Most of the data was acquired by Los Alamos National Laboratory (LANL) in connection with LANL sponsored underground tests. Some was acquired by Los Alamos on tests conducted by the Defense Nuclear Agency (DNA) and Lawrence Livermore National Laboratory (LLNL), and theremore » are some measurements that were acquired by the other test sponsors on their events and provided for inclusion in this data base. Data acquisition, creation of the data base, and development of the data base retrieval program (ntsgm) are the result of work in support of the Los Alamos Field Test Office and the Office of Nonproliferation and Arms Control.« less

Microbiological and biochemical characteristics of ground beef as affected by gamma irradiation, food additives and edible coating film

NASA Astrophysics Data System (ADS)

Ouattara, B.; Giroux, M.; Yefsah, R.; Smoragiewicz, W.; Saucier, L.; Borsa, J.; Lacroix, M.

2002-03-01

The current interest in "minimally processed foods" has attracted the attention for combination of mild treatments to improve food safety and shelf-life extention. The present study was conducted to evaluate the combined effect of gamma irradiation and incorporation of naturally occurring antimicrobial compounds on microbial and biochemistry characteristics of ground beef. Ground beef patties (23% fat ) were purchased from a local grocery store (IGA, Laval, Que., Canada) and divided into 3 separate treatment groups: (i) control (ground beef without additive), (ii) ground beef with 0.5% (w/w) ascorbic acid, and (iii) ground beef with 0.5% ascorbic acid and coated with a protein-based coating containing selected spices. Samples were irradiated at 0, 1, 2, and 3 kGy final dose at the CIC. Samples were stored at 4°C and evaluated periodically for microbial growth, total thiobarbituric reactive substances (TBARS) and free sulfydryl content. At the end of the storage period, Enterobacteriaceae, Lactic acid bacteria, Pseudomonas and Brochothrix thermosphacta were enumerated. Regardless of the treatment group, irradiation significantly ( p⩽0.05) reduced the total aerobic plate counts (APC). Irradiation doses of 1, 2, and 3 kGy produced immediate reduction of 2, 3, and 4 log units of APCs, respectively. Also, shelf-life periods were higher for ground beef samples containing food additives. Lactic acid bacteria and Brochothrix thermosphacta were more resistant to irradiation than Enterobacteriaceae and Pseudomonas. Concentration of TBARS and free sulfydryl concentrations were stabilized during post-irradiation storage for samples containing ascorbic acid and coated with the protein-based coating containing spices.

Enabling technologies for transition to utilization of space-based resources and operations

NASA Technical Reports Server (NTRS)

Sadin, S. R.; Litty, J. D.

1985-01-01

This article explores a potential scenario for the further development of space infrastructure resources and operations management. It is a scenario that transitions from the current ground-based system to an architecture that is predominantly space-based by exploiting key mission systems in an operational support role. If this view is accurate, an examination of the range of potential infrastructure elements and how they might interact in a maximally productive space-based operations complex is needed, innovative technologies beyond the current Shuttle and Space Station legacy need to be identified, and research programs pursued. Development of technologies within the areas of telerobotics, machine autonomy, human autonomy, in-space manufacturing and construction, propulsion and energy is discussed.

Secure Web-based Ground System User Interfaces over the Open Internet

NASA Technical Reports Server (NTRS)

Langston, James H.; Murray, Henry L.; Hunt, Gary R.

1998-01-01

A prototype has been developed which makes use of commercially available products in conjunction with the Java programming language to provide a secure user interface for command and control over the open Internet. This paper reports successful demonstration of: (1) Security over the Internet, including encryption and certification; (2) Integration of Java applets with a COTS command and control product; (3) Remote spacecraft commanding using the Internet. The Java-based Spacecraft Web Interface to Telemetry and Command Handling (Jswitch) ground system prototype provides these capabilities. This activity demonstrates the use and integration of current technologies to enable a spacecraft engineer or flight operator to monitor and control a spacecraft from a user interface communicating over the open Internet using standard World Wide Web (WWW) protocols and commercial off-the-shelf (COTS) products. The core command and control functions are provided by the COTS Epoch 2000 product. The standard WWW tools and browsers are used in conjunction with the Java programming technology. Security is provided with the current encryption and certification technology. This system prototype is a step in the direction of giving scientist and flight operators Web-based access to instrument, payload, and spacecraft data.

A Self-Tuning Kalman Filter for Autonomous Navigation Using the Global Positioning System (GPS)

NASA Technical Reports Server (NTRS)

Truong, Son H.

1999-01-01

Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman filter and GPS (Global Positioning Systems) data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. These systems, however, still rely on manual tuning from analysts. A sophisticated neuro-fuzzy component fully integrated with the flight navigation system can perform the self-tuning capability for the Kalman filter and help the navigation system recover from estimation errors in real time.

A Self-Tuning Kalman Filter for Autonomous Navigation using the Global Positioning System (GPS)

NASA Technical Reports Server (NTRS)

Truong, S. H.

1999-01-01

Most navigation systems currently operated by NASA are ground-based, and require extensive support to produce accurate results. Recently developed systems that use Kalman filter and GPS data for orbit determination greatly reduce dependency on ground support, and have potential to provide significant economies for NASA spacecraft navigation. These systems, however, still rely on manual tuning from analysts. A sophisticated neuro-fuzzy component fully integrated with the flight navigation system can perform the self-tuning capability for the Kalman filter and help the navigation system recover from estimation errors in real time.

A numerical study of the hot gas environment around a STOVL aircraft in ground proximity

NASA Technical Reports Server (NTRS)

Vanoverbeke, Thomas J.; Holdeman, James D.

1988-01-01

The development of Short Takeoff Vertical Landing (STOVL) aircraft has historically been an empirical- and experience-based technology. In this study, a 3-D turbulent flow CFD code was used to calculate the hot gas environment around an STOVL aircraft operating in ground proximity. Preliminary calculations are reported for a typical STOVL aircraft configuration to identify key features of the flow field, and to demonstrate and assess the capability of current 3-D CFD codes to calculate the temperature of the gases ingested at the engine inlet as a function of flow and geometric conditions.

Patterns of genetic diversity in the polymorphic ground snake (Sonora semiannulata).

PubMed

Cox, Christian L; Chippindale, Paul T

2014-08-01

We evaluated the genetic diversity of a snake species with color polymorphism to understand the evolutionary processes that drive genetic structure across a large geographic region. Specifically, we analyzed genetic structure of the highly polymorphic ground snake, Sonora semiannulata, (1) among populations, (2) among color morphs (3) at regional and local spatial scales, using an amplified fragment length polymorphism dataset and multiple population genetic analyses, including FST-based and clustering analytical techniques. Based upon these methods, we found that there was moderate to low genetic structure among populations. However, this diversity was not associated with geographic locality at either spatial scale. Similarly, we found no evidence for genetic divergence among color morphs at either spatial scale. These results suggest that despite dramatic color polymorphism, this phenotypic diversity is not a major driver of genetic diversity within or among populations of ground snakes. We suggest that there are two mechanisms that could explain existing genetic diversity in ground snakes: recent range expansion from a genetically diverse founder population and current or recent gene flow among populations. Our findings have further implications for the types of color polymorphism that may generate genetic diversity in snakes.

On the estimation of jet-induced fountain lift and additional suckdown in hover for two-jet configurations

NASA Technical Reports Server (NTRS)

Kuhn, Richard E.; Bellavia, David C.; Corsiglia, Victor R.; Wardwell, Douglas A.

1991-01-01

Currently available methods for estimating the net suckdown induced on jet V/STOL aircraft hovering in ground effect are based on a correlation of available force data and are, therefore, limited to configurations similar to those in the data base. Experience with some of these configurations has shown that both the fountain lift and additional suckdown are overestimated but these effects cancel each other for configurations within the data base. For other configurations, these effects may not cancel and the net suckdown could be grossly overestimated or underestimated. Also, present methods do not include the prediction of the pitching moments associated with the suckdown induced in ground effect. An attempt to develop a more logically based method for estimating the fountain lift and suckdown based on the jet-induced pressures is initiated. The analysis is based primarily on the data from a related family of three two-jet configurations (all using the same jet spacing) and limited data from two other two-jet configurations. The current status of the method, which includes expressions for estimating the maximum pressure induced in the fountain regions, and the sizes of the fountain and suckdown regions is presented. Correlating factors are developed to be used with these areas and pressures to estimate the fountain lift, the suckdown, and the related pitching moment increments.

Identifying Lagrangian fronts with favourable fishery conditions

NASA Astrophysics Data System (ADS)

Prants, S. V.; Budyansky, M. V.; Uleysky, M. Yu.

2014-08-01

Lagrangian fronts (LFs) in the ocean are defined as boundaries between surface waters with strongly different Lagrangian properties. They can be accurately detected in a given velocity field by computing synoptic maps for displacements of synthetic tracers and other Lagrangian indicators. We use Pacific saury catch and location data for a number of commercial fishery seasons in the region of the northwest Pacific with one of the richest fishery in the world. It is shown statistically that the saury fishing grounds with maximal catches are not randomly distributed over the region but located mainly along the sharp LFs where productive cold waters of the Oyashio Current, warmer waters of the southern branch of the Soya Current, and waters of warm-core Kuroshio rings converge. Computation of those fronts in altimetric geostrophic velocity fields both in the years with the First and Second Oyashio Intrusions shows that in spite of different oceanographic conditions LF locations may serve as good indicators of potential fishing grounds. Possible biophysical reasons for saury aggregation near sharp LFs are discussed. We propose a mechanism for effective export of nutrient rich waters based on stretching of material lines in the vicinity of hyperbolic objects in the ocean. The developed method, based on identifying LFs in any velocity fields, is quite general and may be applied to find potential fishing grounds for the other pelagic fish.

Lightning NOx Statistics Derived by NASA Lightning Nitrogen Oxides Model (LNOM) Data Analyses

NASA Technical Reports Server (NTRS)

Koshak, William; Peterson, Harold

2013-01-01

What is the LNOM? The NASA Marshall Space Flight Center (MSFC) Lightning Nitrogen Oxides Model (LNOM) [Koshak et al., 2009, 2010, 2011; Koshak and Peterson 2011, 2013] analyzes VHF Lightning Mapping Array (LMA) and National Lightning Detection Network(TradeMark) (NLDN) data to estimate the lightning nitrogen oxides (LNOx) produced by individual flashes. Figure 1 provides an overview of LNOM functionality. Benefits of LNOM: (1) Does away with unrealistic "vertical stick" lightning channel models for estimating LNOx; (2) Uses ground-based VHF data that maps out the true channel in space and time to < 100 m accuracy; (3) Therefore, true channel segment height (ambient air density) is used to compute LNOx; (4) True channel length is used! (typically tens of kilometers since channel has many branches and "wiggles"); (5) Distinction between ground and cloud flashes are made; (6) For ground flashes, actual peak current from NLDN used to compute NOx from lightning return stroke; (7) NOx computed for several other lightning discharge processes (based on Cooray et al., 2009 theory): (a) Hot core of stepped leaders and dart leaders, (b) Corona sheath of stepped leader, (c) K-change, (d) Continuing Currents, and (e) M-components; and (8) LNOM statistics (see later) can be used to parameterize LNOx production for regional air quality models (like CMAQ), and for global chemical transport models (like GEOS-Chem).

Electrical Grounding - a Field for Geophysicists and Electrical Engineers Partnership

NASA Astrophysics Data System (ADS)

Freire, P. F.; Pane, E.; Guaraldo, N.

2012-12-01

Technology for designing ground electrodes for high-voltage direct current transmission systems (HVDC) has being using in the last years, deep soil models based on a wide range of geophysical methods. These models shall include detailed representation of shallow soil, down to 100 meters, in order to allow the evaluation of the soil conditions where the ground electrodes will be buried. Also deep soil models are needed, to be used for the interference studies, which shall represent a soil volume of about 15 km deep and a surface area of about 15 to 30 km radius. Large facilities for power plants (hydroelectric and wind farms, for example) and industrial complexes (such as petrochemical plants) has become usual at the current stage of Brazil industrialization. Grounding mats for these facilities are made of a buried cooper mesh, interconnected to a wide variety of metallic masses, such as steel reinforced concrete foundations, ducts in general etc. These grounding systems may present dimensions with the order of hundreds of meters, and, at least in Brazil, are usually calculated by using electrical resistivity soil models, based on short spacing Wenner measurements (with maximum spacing of about 64 m.). The soil model shall be the best possible representation of the environment in which the grounding electrodes are immersed, for the purpose of calculation of resistance or for digital simulation. The model to be obtained is limited by the amount and quality of soil resistivity measurements are available, and the resources to be used in the calculations and simulations. Geophysics uses a wide range of technologies for exploring subsoil, ranging from surface measurements to wells logging - seismic, gravimetric, magnetic, electrical, electromagnetic and radiometric. The electrical and electromagnetic methods includes various measurement techniques (Wenner, Schlumberger, TDEM, Magneto-telluric etc.), which together allow the development of complex resistivity soil models, layered stratified or showing lateral variations, ranging down to several tens of kilometers deep, reaching the crust-mantle interface (typically with the order of 30-40 km). This work aims to analyze the constraints of the current soil models being used for grounding electrodes design, and suggests the need of a soil modeling methodology compatible with large grounding systems. Concerning the aspects related to soil modeling, electrical engineers need to get aware of geophysics resources, such as: - geophysical techniques for soil electrical resistivity prospection (down to about 15 kilometers deep); and - techniques for converting field measured data, from many different geophysical techniques, into adequate soil models for grounding grid simulation. It is also important to equalize the basic knowledge for the professionals that are working together for the specific purpose of soil modeling for electrical grounding studies. The authors have experienced the situation of electrical engineers working with geophysicists, but it was not clear for the latter the effective need of the electrical engineers, and for the engineers it was unknown the available geophysical resources, and also, what to do convert the large amount of soil resistivity data into a reliable soil model.

Immune System Dysregulation and Latent Herpesvirus Reactivation During Winterover at Concordia Station, Dome C, Antarctica

NASA Technical Reports Server (NTRS)

Crucian, B. E.; Feuerecker, M.; Salam, A. P.; Rybka, A.; Stowe, R. P.; Morrels, M.; Meta, S. K.; Quiriarte, H.; Quintens, Roel; Thieme, U.;

Plans for Follow-Up Observations of Kepler Planet Candidates

NASA Astrophysics Data System (ADS)

Gautier, Thomas N., III

2009-05-01

Ground based follow-up observations of transiting planet candidates identified by Kepler are pursued to identify false positives and to search for non-transiting planets in the systems of true transiting planets. I will describe the observational protocols developed by the Kepler team and the web based infrastructure we are using to support the observations. The current state of the Kepler follow-up observations will be reported.

Simulation analysis of a microcomputer-based, low-cost Omega navigation system

NASA Technical Reports Server (NTRS)

Lilley, R. W.; Salter, R. J., Jr.

1976-01-01

The current status of research on a proposed micro-computer-based, low-cost Omega Navigation System (ONS) is described. The design approach emphasizes minimum hardware, maximum software, and the use of a low-cost, commercially-available microcomputer. Currently under investigation is the implementation of a low-cost navigation processor and its interface with an omega sensor to complete the hardware-based ONS. Sensor processor functions are simulated to determine how many of the sensor processor functions can be handled by innovative software. An input data base of live Omega ground and flight test data was created. The Omega sensor and microcomputer interface modules used to collect the data are functionally described. Automatic synchronization to the Omega transmission pattern is described as an example of the algorithms developed using this data base.

Novel semi-airborne CSEM system for the exploration of mineral resources

NASA Astrophysics Data System (ADS)

Nittinger, Christian; Cherevatova, Maria; Becken, Michael; Rochlitz, Raphael; Günther, Thomas; Martin, Tina; Matzander, Ulrich

2017-04-01

Within the DESMEX project (Deep Electromagnetic Sounding for Mineral Exploration), a semi-airborne CSEM system for mineral exploration is developed which aims to achieve a penetration depth of 1 km with a large areal coverage. Harmonically Time-varying electrical currents are injected with a grounded transmitter in order to measure the electric field on the ground and induced magnetic fields with highly sensitive magnetic sensors in the air. To measure the magnetic field and its variations, three-axis induction coils (MFS-11e by Metronix) and fluxgate sensors (Bartington FGS-03) are mounted on the platform towed by a helicopter. In addition, there is a SQUID based magnetometer, developed by IPHT and Supracon AG, available for future measurements. We deploy the different magnetometer sensors to cover a broad frequency range of 1-10000Hz. During the flight, the sensors encounter a broad variety of motion/vibration which produces noise in the magnetic field sensors. Therefore, a high accuracy motion tracking system is installed within the bird and a low vibrating system design needs to be considered in the airborne sensor platform. We conducted several flights with different source positions in a test area in Germany, which is already covered by ground based measurements. Based on the data, we discuss possible calibration schemes which are needed to overcome orthogonality and scaling errors in the fluxgate data as well as orientation errors. We apply noise correction schemes to the data and calculate transfer functions between the magnetic field and the source current. First 1-D inversion models based on the estimated transfer functions are calculated and compared to existing conductivity models from DC geoelectrics and helicopter electromagnetic (HEM) measurements.

Monitoring and remediation of on-farm and off-farm ground current measured as step potential on a Wisconsin dairy farm: A case study.

PubMed

Stetzer, Dave; Leavitt, Adam M; Goeke, Charles L; Havas, Magda

2016-01-01

Ground current commonly referred to as "stray voltage" has been an issue on dairy farms since electricity was first brought to rural America. Equipment that generates high-frequency voltage transients on electrical wires combined with a multigrounded (electrical distribution) system and inadequate neutral returns all contribute to ground current. Despite decades of problems, we are no closer to resolving this issue, in part, due to three misconceptions that are addressed in this study. Misconception 1. The current standard of 1 V at cow contact is adequate to protect dairy cows; Misconception 2. Frequencies higher than 60 Hz do not need to be considered; and Misconception 3. All sources of ground current originate on the farm that has a ground current problem. This case study of a Wisconsin dairy farm documents, 1. how to establish permanent monitoring of ground current (step potential) on a dairy farm; 2. how to determine and remediate both on-farm and off-farm sources contributing to step potential; 3. which step-potential metrics relate to cow comfort and milk production; and 4. how these metrics relate to established standards. On-farm sources include lighting, variable speed frequency drives on motors, radio frequency identification system and off-farm sources are due to a poor primary neutral return on the utility side of the distribution system. A step-potential threshold of 1 V root mean square (RMS) at 60 Hz is inadequate to protect dairy cows as decreases of a few mV peak-peak at higher frequencies increases milk production, reduces milking time and improves cow comfort.

School Personnel Perceptions of Professional School Counselor Role and Function

ERIC Educational Resources Information Center

Coles, Caron N.

2013-01-01

The purpose of this research study was to examine the attitudes held by school-based administrators, teachers, and professional school counselors regarding ideal and actual roles of the professional school counselor. The survey instrument utilized in this research study, the PSCRFA, is grounded in the ASCA model and reflective of current school…

Multi-anode microchannel arrays

NASA Technical Reports Server (NTRS)

Timothy, J. G.; Bybee, R. L.

1977-01-01

A development program is currently being undertaken to produce photon-counting detector arrays which are suitable for use in both ground-based and space-borne instruments and which utilize the full sensitivity, dynamic range and photometric stability of the microchannel array plate (MCP). The construction of the detector arrays and the status of the development program are described.

Use of Research for Transforming Youth Agencies

ERIC Educational Resources Information Center

Baizerman, Michael; Rence, Emily; Johnson, Sean

2013-01-01

Current philosophy and practice urge, even require for funding, that programs be empirically based and grounded in empirically proven emerging, promising, or best practices. In most of the human services, including youth programs, services, and practices, this requirement is a goal as well as an ideal. Empirical research and evaluation can be used…

Teaching Music to Students with Special Needs: A Label-Free Approach

ERIC Educational Resources Information Center

Hammel, Alice; Hourigan, Ryan

2011-01-01

A practical guide & reference manual, "Teaching Music to Students with Special Needs" addresses special needs in the broadest possible sense to equip teachers with proven, research-based curricular strategies that are grounded in both best practice and current special education law. Chapters address the full range of topics and issues music…

W17_geonuc “Application of the Spectral Element Method to improvement of Ground-based Nuclear Explosion Monitoring”

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

Larmat, Carene; Rougier, Esteban; Lei, Zhou

This project is in support of the Source Physics Experiment SPE (Snelson et al. 2013), which aims to develop new seismic source models of explosions. One priority of this program is first principle numerical modeling to validate and extend current empirical models.

Transformation through Expeditionary Change Using Online Learning and Competence-Building Technologies

ERIC Educational Resources Information Center

Norris, Donald M.; Lefrere, Paul

2011-01-01

This paper presents a patterns-based model of the evolution of learning and competence-building technologies, grounded in examples of current practice. The model imagines five simple stages in how institutions use "expeditionary change" to innovate more nimbly. It builds upon three assertions. First, the pervasiveness of web-based…

Optical disk processing of solar images.

NASA Astrophysics Data System (ADS)

Title, A.; Tarbell, T.

The current generation of space and ground-based experiments in solar physics produces many megabyte-sized image data arrays. Optical disk technology is the leading candidate for convenient analysis, distribution, and archiving of these data. The authors have been developing data analysis procedures which use both analog and digital optical disks for the study of solar phenomena.

Comparison of AERMOD and WindTrax dispersion models in determining PM10 emission rates from beef cattle feedlots

USDA-ARS?s Scientific Manuscript database

Reverse dispersion modeling has been used to determine air emission fluxes from ground-level area sources, including open-lot beef cattle feedlots. This research compared AERMOD, a Gaussian-based and currently the U.S. Environmental Protection Agency (EPA) preferred regulatory dispersion model, and ...

Assimilation of spatially sparse in situ soil moisture networks into a continuous model domain

USDA-ARS?s Scientific Manuscript database

Growth in the availability of near-real-time soil moisture observations from ground-based networks has spurred interest in the assimilation of these observations into land surface models via a two-dimensional data assimilation system. However, the design of such systems is currently hampered by our ...

Electromagnetic deep-probing (100-1000 KMS) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

NASA Technical Reports Server (NTRS)

Hermance, J. F. (Principal Investigator)

1982-01-01

The two stages of analysis of MAGSAT magnetic data which are designed to evaluate electromagnetic induction effects are described. The first stage consists of comparison of data from contiguous orbit passes over large scale geologic boundaries, such as ocean-land interfaces, at several levels of magnetic disturbance. The purpose of these comparisons is to separate induction effects from effects of lithospheric magnetization. The procdure for reducing the data includes: (1) identifying and subtracting quiet time effects; (2) modelling and subtracting first order ring current effects; and (3) projecting an orbit track onto a map as a nearly straight line so it can serve as an axis on which to plot the corresponding orbit pass data in the context of geography. The second stage consists of comparison of MAGSAT data with standard hourly observatory data. The purpose is to constrain the time evolution of ionospheric and magnetospheric current systems. Qualitative features of the ground based dataset are discussed. Methods for reducing the ground based data are described.

Autonomous Aerobraking Development Software: Phase 2 Summary

NASA Technical Reports Server (NTRS)

Cianciolo, Alicia D.; Maddock, Robert W.; Prince, Jill L.; Bowes, Angela; Powell, Richard W.; White, Joseph P.; Tolson, Robert; O'Shaughnessy, Daniel; Carrelli, David

2013-01-01

NASA has used aerobraking at Mars and Venus to reduce the fuel required to deliver a spacecraft into a desired orbit compared to an all-propulsive solution. Although aerobraking reduces the propellant, it does so at the expense of mission duration, large staff, and DSN coverage. These factors make aerobraking a significant cost element in the mission design. By moving on-board the current ground-based tasks of ephemeris determination, atmospheric density estimation, and maneuver sizing and execution, a flight project would realize significant cost savings. The NASA Engineering and Safety Center (NESC) sponsored Phase 1 and 2 of the Autonomous Aerobraking Development Software (AADS) study, which demonstrated the initial feasibility of moving these current ground-based functions to the spacecraft. This paper highlights key state-of-the-art advancements made in the Phase 2 effort to verify that the AADS algorithms are accurate, robust and ready to be considered for application on future missions that utilize aerobraking. The advancements discussed herein include both model updates and simulation and benchmark testing. Rigorous testing using observed flight atmospheres, operational environments and statistical analysis characterized the AADS operability in a perturbed environment.

Semi-automated based ground-truthing GUI for airborne imagery

NASA Astrophysics Data System (ADS)

Phan, Chung; Lydic, Rich; Moore, Tim; Trang, Anh; Agarwal, Sanjeev; Tiwari, Spandan

2005-06-01

Over the past several years, an enormous amount of airborne imagery consisting of various formats has been collected and will continue into the future to support airborne mine/minefield detection processes, improve algorithm development, and aid in imaging sensor development. The ground-truthing of imagery is a very essential part of the algorithm development process to help validate the detection performance of the sensor and improving algorithm techniques. The GUI (Graphical User Interface) called SemiTruth was developed using Matlab software incorporating signal processing, image processing, and statistics toolboxes to aid in ground-truthing imagery. The semi-automated ground-truthing GUI is made possible with the current data collection method, that is including UTM/GPS (Universal Transverse Mercator/Global Positioning System) coordinate measurements for the mine target and fiducial locations on the given minefield layout to support in identification of the targets on the raw imagery. This semi-automated ground-truthing effort has developed by the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD), Countermine Division, Airborne Application Branch with some support by the University of Missouri-Rolla.

UAV-guided navigation for ground robot tele-operation in a military reconnaissance environment.

PubMed

Chen, Jessie Y C

2010-08-01

A military reconnaissance environment was simulated to examine the performance of ground robotics operators who were instructed to utilise streaming video from an unmanned aerial vehicle (UAV) to navigate his/her ground robot to the locations of the targets. The effects of participants' spatial ability on their performance and workload were also investigated. Results showed that participants' overall performance (speed and accuracy) was better when she/he had access to images from larger UAVs with fixed orientations, compared with other UAV conditions (baseline- no UAV, micro air vehicle and UAV with orbiting views). Participants experienced the highest workload when the UAV was orbiting. Those individuals with higher spatial ability performed significantly better and reported less workload than those with lower spatial ability. The results of the current study will further understanding of ground robot operators' target search performance based on streaming video from UAVs. The results will also facilitate the implementation of ground/air robots in military environments and will be useful to the future military system design and training community.

Grounding and lightning protection. Volume 5

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

Robinson, M.D.

1987-12-31

Grounding systems protect personnel and equipment by isolating faulted systems and dissipating transient currents. Lightning protection systems minimize the possible consequences of a direct strike by lightning. This volume focuses on design requirements of the grounding system and on present-day concepts used in the design of lightning protection systems. Various types of grounding designs are presented, and their advantages and disadvantages discussed. Safety, of course, is the primary concern of any grounding system. Methods are shown for grounding the non-current-carrying parts of electrical equipment to reduce shock hazards to personnel. Lightning protection systems are installed on tall structures (such asmore » chimneys and cooling towers) to minimize the possibility of structural damage caused by direct lightning strokes. These strokes may carry currents of 200,000 A or more. The volume examines the formation and characteristics of lightning strokes and the way stroke characteristics influence the design of lightning protection systems. Because a large portion of the grounding system is buried in soil or concrete, it is not readily accessible for inspection or repair after its installation. The volume details the careful selection and sizing of materials needed to ensure a long, maintenance-free life for the system. Industry standards and procedures for testing the adequacy of the grounding system are also discussed.« less

Size Effect of Ground Patterns on FM-Band Cross-Talks between Two Parallel Signal Traces of Printed Circuit Boards for Vehicles

NASA Astrophysics Data System (ADS)

Iida, Michihira; Maeno, Tsuyoshi; Wang, Jianqing; Fujiwara, Osamu

Electromagnetic disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common slitting ground patterns. To suppress these kinds of noise currents, we previously measured them for simple two-layer PCBs with two parallel signal traces and slitting or non-slitting ground patterns, and then investigated by the FDTD simulation the reduction characteristics of the FM-band cross-talk noise levels between two parallel signal traces on six simple PCB models having different slitting ground or different divided ground patterns parallel to the traces. As a result, we found that the contributory factor for the FM-band cross-talk reduction is the reduction of mutual inductance between the two parallel traces, and also the noise currents from PCBs can rather be suppressed even if the size of the return ground becomes small. In this study, to investigate this finding, we further simulated the frequency characteristics of cross-talk reduction for additional six simple PCB models with different dividing dimensions ground patterns parallel to the traces, which revealed an interesting phenomenon that cross-talk reduction characteristics do not always decrease with increasing the width between the divided ground patterns.

Modeled ground magnetic signatures of flux transfer events

NASA Technical Reports Server (NTRS)

Mchenry, Mark A.; Clauer, C. Robert

1987-01-01

The magnetic field on the ground due to a small (not greater than 200 km scale size) localized field-aligned current (FAC) system interacting with the ionosphere is calculated in terms of an integral over the ionospheric distribution of FAC. Two different candidate current systems for flux transfer events (FTEs) are considered: (1) a system which has current flowing down the center of a cylindrical flux tube with a return current uniformly distributed along the outside edge; and (2) a system which has upward current on one half of the perimeter of a cylindrical flux tube with downward current on the opposite half. The peak magnetic field on the ground is found to differ by a factor of 2 between the two systems, and the magnetic perturbations are in different directions depending on the observer's position.

MAGNESIUM ALLOYS IN US MILITARY APPLICATIONS: PAST, CURRENT AND FUTURE SOLUTIONS

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

Mathaudhu, Suveen N.; Nyberg, Eric A.

2010-02-26

Since the 1940’s Mg-alloys have been used for military applications, from aircraft components to ground vehicles. The drive for usage was primarily availability and lightweighting of military systems. But the promise of widespread military usage was not met largely based on corrosion and flammability concerns, poor mechanical behavior and inferior ballistic response. This review paper will cover historical, current and potential future applications with a focus on scientific, engineering and social barriers relevant to integration of Mg-alloy. It will also present mechanical and physical property improvements solutions which are currently being developed to address these issues.

High-performance two-axis gimbal system for free space laser communications onboard unmanned aircraft systems

NASA Astrophysics Data System (ADS)

Locke, Michael; Czarnomski, Mariusz; Qadir, Ashraf; Setness, Brock; Baer, Nicolai; Meyer, Jennifer; Semke, William H.

2011-03-01

A custom designed and manufactured gimbal with a wide field-of-view and fast response time is developed. This enhanced custom design is a 24 volt system with integrated motor controllers and drivers which offers a full 180o fieldof- view in both azimuth and elevation; this provides a more continuous tracking capability as well as increased velocities of up to 479° per second. The addition of active high-frequency vibration control, to complement the passive vibration isolation system, is also in development. The ultimate goal of this research is to achieve affordable, reliable, and secure air-to-air laser communications between two separate remotely piloted aircraft. As a proof-of-concept, the practical implementation of an air-to-ground laserbased video communications payload system flown by a small Unmanned Aerial Vehicle (UAV) will be demonstrated. A numerical tracking algorithm has been written, tested, and used to aim the airborne laser transmitter at a stationary ground-based receiver with known GPS coordinates; however, further refinement of the tracking capabilities is dependent on an improved gimbal design for precision pointing of the airborne laser transmitter. The current gimbal pointing system is a two-axis, commercial-off-the-shelf component, which is limited in both range and velocity. The current design is capable of 360o of pan and 78o of tilt at a velocity of 60o per second. The control algorithm used for aiming the gimbal is executed on a PC-104 format embedded computer onboard the payload to accurately track a stationary ground-based receiver. This algorithm autonomously calculates a line-of-sight vector in real-time by using the UAV autopilot's Differential Global Positioning System (DGPS) which provides latitude, longitude, and altitude and Inertial Measurement Unit (IMU) which provides the roll, pitch, and yaw data, along with the known Global Positioning System (GPS) location of the ground-based photodiode array receiver.

30 CFR 77.902-3 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Attachment of ground conductors and ground check wires to equipment frames; use of separate connections. 77.902-3 Section 77.902-3 Mineral...-Voltage Alternating Current Circuits § 77.902-3 Attachment of ground conductors and ground check wires to...

30 CFR 77.902-3 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Attachment of ground conductors and ground check wires to equipment frames; use of separate connections. 77.902-3 Section 77.902-3 Mineral...-Voltage Alternating Current Circuits § 77.902-3 Attachment of ground conductors and ground check wires to...

Measurement of Walking Ground Reactions in Real-Life Environments: A Systematic Review of Techniques and Technologies.

PubMed

Shahabpoor, Erfan; Pavic, Aleksandar

2017-09-12

Monitoring natural human gait in real-life environments is essential in many applications, including quantification of disease progression, monitoring the effects of treatment, and monitoring alteration of performance biomarkers in professional sports. Nevertheless, developing reliable and practical techniques and technologies necessary for continuous real-life monitoring of gait is still an open challenge. A systematic review of English-language articles from scientific databases including Scopus, ScienceDirect, Pubmed, IEEE Xplore, EBSCO and MEDLINE were carried out to analyse the 'accuracy' and 'practicality' of the current techniques and technologies for quantitative measurement of the tri-axial walking ground reactions outside the laboratory environment, and to highlight their strengths and shortcomings. In total, 679 relevant abstracts were identified, 54 full-text papers were included in the paper and the quantitative results of 17 papers were used for meta-analysis and comparison. Three classes of methods were reviewed: (1) methods based on measured kinematic data; (2) methods based on measured plantar pressure; and (3) methods based on direct measurement of ground reactions. It was found that all three classes of methods have competitive accuracy levels with methods based on direct measurement of the ground reactions showing highest accuracy while being least practical for long-term real-life measurement. On the other hand, methods that estimate ground reactions using measured body kinematics show highest practicality of the three classes of methods reviewed. Among the most prominent technical and technological challenges are: (1) reducing the size and price of tri-axial load-cells; (2) improving the accuracy of orientation measurement using IMUs; (3) minimizing the number and optimizing the location of required IMUs for kinematic measurement; (4) increasing the durability of pressure insole sensors, and (5) enhancing the robustness and versatility of the ground reactions estimation methods to include pathological gaits and natural variability of gait in real-life physical environment.

Measurement of Walking Ground Reactions in Real-Life Environments: A Systematic Review of Techniques and Technologies

PubMed Central

Shahabpoor, Erfan; Pavic, Aleksandar

2017-01-01

Monitoring natural human gait in real-life environments is essential in many applications, including quantification of disease progression, monitoring the effects of treatment, and monitoring alteration of performance biomarkers in professional sports. Nevertheless, developing reliable and practical techniques and technologies necessary for continuous real-life monitoring of gait is still an open challenge. A systematic review of English-language articles from scientific databases including Scopus, ScienceDirect, Pubmed, IEEE Xplore, EBSCO and MEDLINE were carried out to analyse the ‘accuracy’ and ‘practicality’ of the current techniques and technologies for quantitative measurement of the tri-axial walking ground reactions outside the laboratory environment, and to highlight their strengths and shortcomings. In total, 679 relevant abstracts were identified, 54 full-text papers were included in the paper and the quantitative results of 17 papers were used for meta-analysis and comparison. Three classes of methods were reviewed: (1) methods based on measured kinematic data; (2) methods based on measured plantar pressure; and (3) methods based on direct measurement of ground reactions. It was found that all three classes of methods have competitive accuracy levels with methods based on direct measurement of the ground reactions showing highest accuracy while being least practical for long-term real-life measurement. On the other hand, methods that estimate ground reactions using measured body kinematics show highest practicality of the three classes of methods reviewed. Among the most prominent technical and technological challenges are: (1) reducing the size and price of tri-axial load-cells; (2) improving the accuracy of orientation measurement using IMUs; (3) minimizing the number and optimizing the location of required IMUs for kinematic measurement; (4) increasing the durability of pressure insole sensors, and (5) enhancing the robustness and versatility of the ground reactions estimation methods to include pathological gaits and natural variability of gait in real-life physical environment. PMID:28895909

Far infrared supplement: Catalog of infrared observations

NASA Technical Reports Server (NTRS)

Gezari, D. Y.; Schmitz, M.; Mead, J. M.

1982-01-01

The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.

QIPS: quantum information and quantum physics in space

NASA Astrophysics Data System (ADS)

Schmitt-Manderbach, Tobias; Scheidl, Thomas; Ursin, Rupert; Tiefenbacher, Felix; Weier, Henning; Fürst, Martin; Jennewein, T.; Perdigues, J.; Sodnik, Z.; Rarity, J.; Zeilinger, Anton; Weinfurter, Harald

2017-11-01

The aim of the QIPS project (financed by ESA) is to explore quantum phenomena and to demonstrate quantum communication over long distances. Based on the current state-of-the-art a first study investigating the feasibility of space based quantum communication has to establish goals for mid-term and long-term missions, but also has to test the feasibility of key issues in a long distance ground-to-ground experiment. We have therefore designed a proof-of-concept demonstration for establishing single photon links over a distance of 144 km between the Canary Islands of La Palma and Tenerife to evaluate main limitations for future space experiments. Here we report on the progress of this project and present first measurements of crucial parameters of the optical free space link.

High-speed optical feeder-link system using adaptive optics

NASA Astrophysics Data System (ADS)

Arimoto, Yoshinori; Hayano, Yutaka; Klaus, Werner

1997-05-01

We propose a satellite laser communication system between a ground station and a geostationary satellite, named high- speed optical feeder link system. It is based on the application of (a) high-speed optical devices, which have been developed for ground-based high-speed fiber-optic communications, and (b) the adaptive optics which compensates wavefront distortions due to atmospheric turbulences using a real time feedback control. A link budget study shows that a system with 10-Gbps bit-rate are available assuming the state-of-the-art device performance of the Er-doped fiber amplifier. We further discuss preliminary measurement results of the atmospheric turbulence at the telescope site in Tokyo, and present current study on the design of the key components for the feeder-link laser transceiver.

30 CFR 77.701-2 - Approved methods of grounding metallic frames, casings, and other enclosures of electric...

Code of Federal Regulations, 2010 CFR

2010-07-01

... from a direct-current power system with one polarity grounded will be approved: (1) A solid connection..., casings, and other enclosures of electric equipment receiving power from a direct-current power system. 77... enclosures of electric equipment receiving power from a direct-current power system. (a) The following...

30 CFR 77.701-2 - Approved methods of grounding metallic frames, casings, and other enclosures of electric...

Code of Federal Regulations, 2011 CFR

2011-07-01

... from a direct-current power system with one polarity grounded will be approved: (1) A solid connection..., casings, and other enclosures of electric equipment receiving power from a direct-current power system. 77... enclosures of electric equipment receiving power from a direct-current power system. (a) The following...

Autogenic feedback training experiment: A preventative method for space motion sickness

NASA Technical Reports Server (NTRS)

Cowings, Patricia S.

1993-01-01

Space motion sickness is a disorder which produces symptoms similar to those of motion sickness on Earth. This syndrome has affected approximately 50 percent of all astronauts and cosmonauts exposed to microgravity in space, but it differs from what is commonly known as motion sickness in a number of critical ways. There is currently no ground-based method for predicting susceptibility to motion sickness in space. Antimotion sickness drugs have had limited success in preventing or counteracting symptoms in space, and frequently caused debilitating side effects. The objectives were: (1) to evaluate the effectiveness of Autogenic-Feedback Training as a countermeasure for space motion sickness; (2) to compare physiological data and in-flight symptom reports to ground-based motion sickness data; and (3) to predict susceptibility to space motion sickness based on pre-flight data of each treatment group crew member.

Solar Spicules Near and at the Limb, Observed from Hinode

NASA Technical Reports Server (NTRS)

Sterling, Alphonse C.; Moore, Ronald

2009-01-01

Solar spicules appear as narrow jets emanating from the chromosphere and extending into the corona. They have been observed for over a hundred years, mainly in chromospheric spectral lines such as H-alpha. Because they are at the limit of visibility of ground-based instruments, their nature has long been a puzzle (Beckers 1968, 1972; Sterling 2000). In recent years however, vast progress has been made in understanding them both theoretically and observationally, as spicule studies have undergone a revolution because of the superior resolution and time cadence of ground-based and space-based instruments (e.g., DePontieu et al. 2004). Even more rapid progress is currently underway, due to the Solar Optical Telescope (SOT) instrument on the Hinode spacecraft (e.g., De Pontieu et al. 2007a, 2007b). Here we present observations of spicules from Hinode SOT, as seen near the limb with the Ca II filtergraph.

Advanced training systems

NASA Technical Reports Server (NTRS)

Savely, Robert T.; Loftin, R. Bowen

1990-01-01

Training is a major endeavor in all modern societies. Common training methods include training manuals, formal classes, procedural computer programs, simulations, and on-the-job training. NASA's training approach has focussed primarily on on-the-job training in a simulation environment for both crew and ground based personnel. NASA must explore new approaches to training for the 1990's and beyond. Specific autonomous training systems are described which are based on artificial intelligence technology for use by NASA astronauts, flight controllers, and ground based support personnel that show an alternative to current training systems. In addition to these specific systems, the evolution of a general architecture for autonomous intelligent training systems that integrates many of the features of traditional training programs with artificial intelligence techniques is presented. These Intelligent Computer Aided Training (ICAT) systems would provide much of the same experience that could be gained from the best on-the-job training.

Deep-space navigation applications of improved ground-based optical astrometry

NASA Technical Reports Server (NTRS)

Null, G. W.; Owen, W. M., Jr.; Synnott, S. P.

1992-01-01

Improvements in ground-based optical astrometry will eventually be required for navigation of interplanetary spacecraft when these spacecraft communicate at optical wavelengths. Although such spacecraft may be some years off, preliminary versions of the astrometric technology can also be used to obtain navigational improvements for the Galileo and Cassini missions. This article describes a technology-development and observational program to accomplish this, including a cooperative effort with U.S. Naval Observatory Flagstaff Station. For Galileo, Earth-based astrometry of Jupiter's Galilean satellites may improve their ephemeris accuracy by a factor of 3 to 6. This would reduce the requirements for onboard optical navigation pictures, so that more of the data transmission capability (currently limited by high-gain antenna deployment problems) can be used for science data. Also, observations of European Space Agency (ESA) Hipparcos stars with asteroid 243 Ida may provide significantly improved navigation accuracy for a planned August 1993 Galileo spacecraft encounter.

Accurate measurements of solar spectral irradiance between 4000-10000 cm-1

NASA Astrophysics Data System (ADS)

Elsey, J.; Coleman, M. D.; Gardiner, T.; Shine, K. P.

2017-12-01

The near-infrared solar spectral irradiance (SSI) is an important input into simulations of weather and climate; the distribution of energy throughout this region of the spectrum influences atmospheric heating rates and the global hydrological cycle through absorption and scattering by water vapour. Current measurements by a mixture of ground-based and space-based instruments show differences of around 10% in the 4000-7000 cm-1 region, with no resolution to this controversy in sight. This work presents observations of SSI taken using a ground-based Fourier Transform spectrometer between 4000-10000 cm-1 at a field site in Camborne, UK, with particular focus on a rigorously defined uncertainty budget. While there is good agreement between this work and the commonly-used ATLAS3 spectrum between 7000-10000 cm-1, the SSI is systematically lower by 10% than ATLAS3 between 4000-7000 cm-1, with no overlap within the k = 2 measurement uncertainties.

Containerless Studies of Nucleation and Undercooling

NASA Technical Reports Server (NTRS)

Trinh, E. H.

1985-01-01

The long term research goals are to perform experiments to determine the achievable limits of undercooling, the characteristics of heterogeneous nucleation, and the physical properties of significantly undercooled melts. The techniques used are based on the newly developed containerless manipulation methods afforded by acoustic levitation. Ground based investigations involved 0.1 to 2 mm specimens of pure metals and alloys (In, Ga, Sn, Ga-In, ...) as well as glass-forming organic compounds (O-Terphenyl). A currently operating ultrasonic high temperature apparatus has allowed the ground-based levitation of 1 to 2 mm samples of solid aluminum at 550 deg C in an argon atmosphere. Present work is concentrating on the undercooling of pure metal samples (In, Sn), and on the measurements of surface tension and viscosity of the undercooled melts via shape oscillation techniques monitored through optical detection methods. The sound velocity of undercooled O-Terphenyl is being measured in an immiscible liquid levitation cells.

30 CFR 75.906 - Trailing cables for mobile equipment, ground wires, and ground check wires.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Trailing cables for mobile equipment, ground... Underground Low- and Medium-Voltage Alternating Current Circuits § 75.906 Trailing cables for mobile equipment, ground wires, and ground check wires. [Statutory Provisions] Trailing cables for mobile equipment shall...

30 CFR 75.906 - Trailing cables for mobile equipment, ground wires, and ground check wires.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Trailing cables for mobile equipment, ground... Underground Low- and Medium-Voltage Alternating Current Circuits § 75.906 Trailing cables for mobile equipment, ground wires, and ground check wires. [Statutory Provisions] Trailing cables for mobile equipment shall...

30 CFR 75.906 - Trailing cables for mobile equipment, ground wires, and ground check wires.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Trailing cables for mobile equipment, ground... Underground Low- and Medium-Voltage Alternating Current Circuits § 75.906 Trailing cables for mobile equipment, ground wires, and ground check wires. [Statutory Provisions] Trailing cables for mobile equipment shall...

Autonomous Mission Operations for Sensor Webs

NASA Astrophysics Data System (ADS)

Underbrink, A.; Witt, K.; Stanley, J.; Mandl, D.

2008-12-01

We present interim results of a 2005 ROSES AIST project entitled, "Using Intelligent Agents to Form a Sensor Web for Autonomous Mission Operations", or SWAMO. The goal of the SWAMO project is to shift the control of spacecraft missions from a ground-based, centrally controlled architecture to a collaborative, distributed set of intelligent agents. The network of intelligent agents intends to reduce management requirements by utilizing model-based system prediction and autonomic model/agent collaboration. SWAMO agents are distributed throughout the Sensor Web environment, which may include multiple spacecraft, aircraft, ground systems, and ocean systems, as well as manned operations centers. The agents monitor and manage sensor platforms, Earth sensing systems, and Earth sensing models and processes. The SWAMO agents form a Sensor Web of agents via peer-to-peer coordination. Some of the intelligent agents are mobile and able to traverse between on-orbit and ground-based systems. Other agents in the network are responsible for encapsulating system models to perform prediction of future behavior of the modeled subsystems and components to which they are assigned. The software agents use semantic web technologies to enable improved information sharing among the operational entities of the Sensor Web. The semantics include ontological conceptualizations of the Sensor Web environment, plus conceptualizations of the SWAMO agents themselves. By conceptualizations of the agents, we mean knowledge of their state, operational capabilities, current operational capacities, Web Service search and discovery results, agent collaboration rules, etc. The need for ontological conceptualizations over the agents is to enable autonomous and autonomic operations of the Sensor Web. The SWAMO ontology enables automated decision making and responses to the dynamic Sensor Web environment and to end user science requests. The current ontology is compatible with Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) Sensor Model Language (SensorML) concepts and structures. The agents are currently deployed on the U.S. Naval Academy MidSTAR-1 satellite and are actively managing the power subsystem on-orbit without the need for human intervention.

Hail prevention by ground-based silver iodide generators: Results of historical and modern field projects

NASA Astrophysics Data System (ADS)

Dessens, J.; Sánchez, J. L.; Berthet, C.; Hermida, L.; Merino, A.

2016-03-01

The science of hail suppression by silver iodide (AgI) cloud seeding was developed during the second half of the 20th century in laboratory and tested in several research or operational projects using three delivery methods for the ice forming particles: ground generators, aircraft, and rockets. The randomization process for the seeding was often considered as the imperative method for a better evaluation but failed to give firm results, mostly because the projects did not last long enough considering the hazardous occurrence of severe hailfalls, and also probably due to the use of improper hail parameters. At the same time and until now, a continuous long-term research and operational field project (1952-2015) using ground generator networks has been conducted in France under the leadership of the Association Nationale d'Etude et de Lutte contre les Fléaux Atmosphériques (ANELFA), with a control initially based on annual insurance loss-to-risk ratios, then on hailpad data. More recently (2000-2009), a companion ground seeding project was developed in the north of Spain, with control mostly based on microphysical and hailpad data. The present paper, which focuses on hail suppression by ground seeding, reviews the production of the AgI nuclei, their dispersion and measurement in the atmosphere, as well as their observed or simulated effects in clouds. The paper summarizes the results of the main historical projects in Switzerland, Argentina, and North America, and finally concentrates on the current French and Spanish projects, with a review of already published results, complemented by new ones recently collected in Spain. The conclusion, at least for France and Spain, is that if ground seeding is performed starting 3 hours before the hail falls at the ground with a 10-km mesh AgI generator network located in the developing hailstorm areas, each generator burning about 9 g of AgI per hour, the hailfall energy of the most severe hail days is decreased by about 50%.

New Directions in Space Operations Services in Support of Interplanetary Exploration

NASA Technical Reports Server (NTRS)

Bradford, Robert N.

2005-01-01

To gain access to the necessary operational processes and data in support of NASA's Lunar/Mars Exploration Initiative, new services, adequate levels of computing cycles and access to myriad forms of data must be provided to onboard spacecraft and ground based personnel/systems (earth, lunar and Martian) to enable interplanetary exploration by humans. These systems, cycles and access to vast amounts of development, test and operational data will be required to provide a new level of services not currently available to existing spacecraft, on board crews and other operational personnel. Although current voice, video and data systems in support of current space based operations has been adequate, new highly reliable and autonomous processes and services will be necessary for future space exploration activities. These services will range from the more mundane voice in LEO to voice in interplanetary travel which because of the high latencies will require new voice processes and standards. New services, like component failure predictions based on data mining of significant quantities of data, located at disparate locations, will be required. 3D or holographic representation of onboard components, systems or family members will greatly improve maintenance, operations and service restoration not to mention crew morale. Current operational systems and standards, like the Internet Protocol, will not able to provide the level of service required end to end from an end point on the Martian surface like a scientific instrument to a researcher at a university. Ground operations whether earth, lunar or Martian and in flight operations to the moon and especially to Mars will require significant autonomy that will require access to highly reliable processing capabilities, data storage based on network storage technologies. Significant processing cycles will be needed onboard but could be borrowed from other locations either ground based or onboard other spacecraft. Reliability will be a key factor with onboard and distributed backup processing an absolutely necessary requirement. Current cluster processing/Grid technologies may provide the basis for providing these services. An overview of existing services, future services that will be required and the technologies and standards required to be developed will be presented. The purpose of this paper will be to initiate a technological roadmap, albeit at a high level, of current voice, video, data and network technologies and standards (which show promise for adaptation or evolution) to what technologies and standards need to be redefined, adjusted or areas where new ones require development. The roadmap should begin the differentiation between non manned and manned processes/services where applicable. The paper will be based in part on the activities of the CCSDS Monitor and Control working group which is beginning the process of standardization of the these processes. Another element of the paper will be based on an analysis of current technologies supporting space flight processes and services at JSC, MSFC, GSFC and to a lesser extent at KSC. Work being accomplished in areas such as Grid computing, data mining and network storage at ARC, IBM and the University of Alabama at Huntsville will be researched and analyzed.

Simultaneous observation of the poleward expansion of substorm electrojet activity and the tailward expansion of current sheet disruption in the near-earth magnetotail

NASA Technical Reports Server (NTRS)

Lopez, R. E.; Koskinen, H. E. J.; Pulkkinen, T. I.; Bosinger, T.; Mcentire, R. W.; Potemra, T. A.

1993-01-01

A substorm that occurred on 7 June 1985 at 2209 UT for which simultaneous measurements from ground stations and CCE are available is considered. The event occurred during a close conjunction between CCE, the EISCAT magnetometer cross, and the STARE radar, allowing a detailed comparison of satellite and ground-based data. Two discrete activations took place during the first few minutes of this substorm: the expansion phase onset at 2209 UT and an intensification at 2212 UT, corresponding to a poleward expansion of activity. The energetic particle data indicate that the active region of the magnetotail during the 2212 UT intensification was located tailward of the active region at 2209 UT. This is direct evidence for a correspondence between tailward expansion of localized activity in the near-earth magnetotail (current disruption and particle energization) and poleward expansion of activity (electrojet formation) in the ionosphere.

A ground-based memory state tracker for satellite on-board computer memory

NASA Technical Reports Server (NTRS)

Quan, Alan; Angelino, Robert; Hill, Michael; Schwuttke, Ursula; Hervias, Felipe

1993-01-01

The TOPEX/POSEIDON satellite, currently in Earth orbit, will use radar altimetry to measure sea surface height over 90 percent of the world's ice-free oceans. In combination with a precise determination of the spacecraft orbit, the altimetry data will provide maps of ocean topography, which will be used to calculate the speed and direction of ocean currents worldwide. NASA's Jet Propulsion Laboratory (JPL) has primary responsibility for mission operations for TOPEX/POSEIDON. Software applications have been developed to automate mission operations tasks. This paper describes one of these applications, the Memory State Tracker, which allows the ground analyst to examine and track the contents of satellite on-board computer memory quickly and efficiently, in a human-readable format, without having to receive the data directly from the spacecraft. This process is accomplished by maintaining a groundbased mirror-image of spacecraft On-board Computer memory.

46 CFR 129.370 - Equipment grounding.

Code of Federal Regulations, 2011 CFR

2011-10-01

... and to a common ground by a conductor not normally carrying current. (b) Each metallic case of... grounding conductor must be sized to comply with section 250-95 of NEC (NFPA 70). (d) Each nonmetallic mast and topmast must have a lightning-ground conductor. ...

46 CFR 129.370 - Equipment grounding.

Code of Federal Regulations, 2010 CFR

2010-10-01

... and to a common ground by a conductor not normally carrying current. (b) Each metallic case of... grounding conductor must be sized to comply with section 250-95 of NEC (NFPA 70). (d) Each nonmetallic mast and topmast must have a lightning-ground conductor. ...

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling: M-I-T COUPLING OF TCV

DOE PAGES

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; ...

2017-03-11

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements withmore » corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.« less

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling: M-I-T COUPLING OF TCV

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

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements withmore » corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.« less

Ionospheric magnetic signals during conjunctions between ground based and Swarm satellite observations

NASA Astrophysics Data System (ADS)

Saturnino, Diana; Olsen, Nils; Finlay, Chris

2017-04-01

High-precision magnetic measurements collected by satellites such as Swarm or CHAMP,flying at altitudes between 300 and 800km, allow for improved geomagnetic field modelling. An accurate description of the internal (core and crust) field must account for contributions from other sources, such as the ionosphere and magnetosphere. However, the description of the rapidly changing external field contributions, particularly during the quiet times from which the data are selected, constitutes a major challenge of the construction of such models. Our study attempts to obtain improved knowledge on ionospheric field contributions during quiet times conditions, in particular during night local times. We use two different datasets: ground magnetic observatories time series (obtained below the ionospheric E-layer currents), and Swarm satellites measurements acquired above these currents. First, we remove from the data estimates of the core, lithospheric and large-scale magnetospheric magnetic contributions as given by the CHAOS-6 model, to obtain corrected time series. Then, we focus on the differences of the corrected time series: for a pair of ground magnetic observatories, we determine the time series of the difference, and similarly we determine time series differences at satellite altitude, given by the difference between the Swarm Alpha and Charlie satellites taken in the vicinity of the ground observatory locations. The obtained differences time series are analysed regarding their temporal and spatial scales variations, with emphasis on measurements during night local times.

Characterization of Radiation-Resistant Vegetative Bacteria in Beef1

PubMed Central

Welch, Ardyce B.; Maxcy, R. B.

1975-01-01

Ground beef contains numerous microorganisms of various types. The commonly recognized bacteria are associated with current problems of spoilage. Irradiation, however, contributes a new factor through selective destruction of the microflora. The residual microorganisms surviving a nonsterilizing dose are predominantly gram-negative coccobacilli. Various classifications have been given, e.g., Moraxella, Acinetobacter, Achromobacter, etc. For a more detailed study of these radiation-resistant bacteria occurring in ground beef, an enrichment procedure was used for isolation. By means of morphological and biochemical tests, most of the isolates were found to be Moraxella, based on current classifications. The range of growth temperatures was from 2 to 50 C. These bacteria were relatively heat sensitive, e.g., D10 of 5.4 min at 70 C or less. The radiation resistance ranged from D10 values of 273 to 2,039 krad. Thus, some were more resistant than any presently recognized spores. A reference culture of Moraxella osloensis was irradiated under conditions comparable to the enrichment procedure used with the ground beef. The only apparent changes were in morphology and penicillin sensitivity. However, after a few subcultures these bacteria reverted to the characteristics of the parent strain. Thus, it is apparent that these isolates are a part of the normal flora of ground beef and not aberrant forms arising from the irradiation procedure. The significance, if any, of these bacteria is not presently recognized. Images PMID:1164011

Characterization of radiation-resistant vegetative bacteria in beef.

PubMed

Welch, A B; Maxcy, R B

1975-08-01

Ground beef contains numerous microorganisms of various types. The commonly recognized bacteria are associated with current problems of spoilage. Irradiation, however, contributes a new factor through selective destruction of the microflora. The residual microorganisms surviving a nonsterilizing dose are predominantly gram-negative coccobacilli. Various classifications have been given, e.g., Moraxella, Acinetobacter, Achromobacter, etc. For a more detailed study of these radiation-resistant bacteria occurring in ground beef, an enrichment procedure was used for isolation. By means of morphological and biochemical tests, most of the isolates were found to be Moraxella, based on current classifications. The range of growth temperatures was from 2 to 50 C. These bacteria were relatively heat sensitive, e.g., D10 of 5.4 min at 70 C or less. The radiation resistance ranged from D10 values of 273 to 2,039 krad. Thus, some were more resistant than any presently recognized spores. A reference culture of Moraxella osloensis was irradiated under conditions comparable to the enrichment procedure used with the ground beef. The only apparent changes were in morphology and penicillin sensitivity. However, after a few subcultures these bacteria reverted to the characteristics of the parent strain. Thus, it is apparent that these isolates are a part of the normal flora of ground beef and not aberrant forms arising from the irradiation procedure. The significance, if any, of these bacteria is not presently recognized.

Improved Discretization of Grounding Lines and Calving Fronts using an Embedded-Boundary Approach in BISICLES

NASA Astrophysics Data System (ADS)

Martin, D. F.; Cornford, S. L.; Schwartz, P.; Bhalla, A.; Johansen, H.; Ng, E.

2017-12-01

Correctly representing grounding line and calving-front dynamics is of fundamental importance in modeling marine ice sheets, since the configuration of these interfaces exerts a controlling influence on the dynamics of the ice sheet. Traditional ice sheet models have struggled to correctly represent these regions without very high spatial resolution. We have developed a front-tracking discretization for grounding lines and calving fronts based on the Chombo embedded-boundary cut-cell framework. This promises better representation of these interfaces vs. a traditional stair-step discretization on Cartesian meshes like those currently used in the block-structured AMR BISICLES code. The dynamic adaptivity of the BISICLES model complements the subgrid-scale discretizations of this scheme, producing a robust approach for tracking the evolution of these interfaces. Also, the fundamental discontinuous nature of flow across grounding lines is respected by mathematically treating it as a material phase change. We present examples of this approach to demonstrate its effectiveness.

Section on Supernova Remnants and Cosmic Rays of the White Paper on the Status and Future of Ground-Based Gamma-Ray Astronomy

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

Pohl, M.; /Iowa State U.; Abdo, Aous A.

This is a report on the findings of the SNR/cosmic-ray working group for the white paper on the status and future of ground-based gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe shell-type supernova remnants and diffuse emission from cosmic rays at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to study the acceleration of relativistic charged particles which is one of the mainmore » unsolved, yet fundamental, problems in modern astrophysics. The acceleration of particles relies on interactions between energetic particles and magnetic turbulence. In the case of SNRs we can perform spatially resolved studies in systems with known geometry, and the plasma physics deduced from these observations will help us to understand other systems where rapid particle acceleration is believed to occur and where observations as detailed as those of SNRs are not possible.« less

Pheromone-based coordination strategy to static sensors on the ground and unmanned aerial vehicles carried sensors

NASA Astrophysics Data System (ADS)

Pignaton de Freitas, Edison; Heimfarth, Tales; Pereira, Carlos Eduardo; Morado Ferreira, Armando; Rech Wagner, Flávio; Larsson, Tony

2010-04-01

A current trend that is gaining strength in the wireless sensor network area is the use of heterogeneous sensor nodes in one coordinated overall network, needed to fulfill the requirements of sophisticated emerging applications, such as area surveillance systems. One of the main concerns when developing such sensor networks is how to provide coordination among the heterogeneous nodes, in order to enable them to efficiently respond the user needs. This study presents an investigation of strategies to coordinate a set of static sensor nodes on the ground cooperating with wirelessly connected Unmanned Aerial Vehicles (UAVs) carrying a variety of sensors, in order to provide efficient surveillance over an area of interest. The sensor nodes on the ground are set to issue alarms on the occurrence of a given event of interest, e.g. entrance of a non-authorized vehicle in the area, while the UAVs receive the issued alarms and have to decide which of them is the most suitable to handle the issued alarm. A bio-inspired coordination strategy based on the concept of pheromones is presented. As a complement of this strategy, a utility-based decision making approach is proposed.

Characterization of air pollution in Mexico City by remote sensing

NASA Astrophysics Data System (ADS)

Grutter, Michel; Arellano, Josue; Bezanilla, Alejandro; Friedrich, Martina; Plaza, Eddy; Rivera, Claudia; Stremme, Wolfgang

2014-05-01

Megacities, like the Mexico City Metropolitan Area, are home to a large fraction of the population of the world and a consequence is that they are one of the biggest sources of contaminants and greenhouse gases emitted to the atmosphere. The pollution is visible form space through remote sensing instruments, however, satellite observations like those with NADIR viewing geometries have decreased sensitivity near the Earth's surface and the analytical algorithms are in generally optimized to detect pollution plumes in the free troposphere or above. Ground-based observations are thus necessary in order to reduce uncertainties from satellite products. As we will show, Mexico City and its surroundings is well characterized by ground-based remote sensing measurements like from two stations with solar-absorption FTIR spectrometers and a newly formed network of MAX-DOAS and LIDAR instruments. Examples will be provided of how the evolution of the mixing-layer height is characterized and the vertical column densities and profiles of gases in and outside the urban area are continuously monitored. The combination of ground-based and space-borne measurements are used to improve the current knowledge in the spatial and temporal distribution of key pollutants from this megacity.

Preparing for TESS: Precision Ground-based Light-curves of Newly Discovered Transiting Exoplanets

NASA Astrophysics Data System (ADS)

Li, Yiting; Stefansson, Gudmundur; Mahadevan, Suvrath; Monson, Andy; Hebb, Leslie; Wisniewski, John; Huehnerhoff, Joseph

2018-01-01

NASA’s Transiting Exoplanet Survey Satellite (TESS), to be launched in early 2018, is expected to catalog a myriad of transiting exoplanet candidates ranging from Earth-sized to gas giants, orbiting a diverse range of stellar types in the solar neighborhood. In particular, TESS will find small planets orbiting the closest and brightest stars, and will enable detailed atmospheric characterizations of planets with current and future telescopes. In the TESS era, ground-based follow-up resources will play a critical role in validating and confirming the planetary nature of the candidates TESS will discover. Along with confirming the planetary nature of exoplanet transits, high precision ground-based transit observations allow us to put further constraints on exoplanet orbital parameters and transit timing variations. In this talk, we present new observations of transiting exoplanets recently discovered by the K2 mission, using the optical diffuser on the 3.5m ARC Telescope at Apache Point Observatory. These include observations of the mini-Neptunes K2-28b and K2-104b orbiting early-to-mid M-dwarfs. In addition, other recent transit observations performed using the robotic 30cm telescope at Las Campanas Observatory in Chile will be presented.

Investigation of GICs Associated with Large dB/dt Variations in Space

NASA Astrophysics Data System (ADS)

Dimitrakoudis, S.; Mann, I. R.; Murphy, K. R.; Rae, J.; Denton, M.; Milling, D. K.

2016-12-01

Geomagnetically induced currents (GICs) can be driven in terrestrial electrical power grids as a result of the induced electric fields arising from magnetic field changes driven in the coupled magnetosphere-ionosphere-ground system. Substorms are often hypothesised to be associated with the largest GIC effects on the ground, especially at higher latitudes. However, recent studies have suggested that other dayside phenomena such as sudden impulses and even ULF wave trains might also drive significant GICs. Using data from the CARISMA ground-based magnetometer network we examine the GIC response driven from a variety of magnetospheric processes. In particular we focus on events where large dB/dt is observed in-situ on GOES East and West satellites. Auroras, resulting from magnetospheric substorms, give us a dynamical view of sudden destabilizations in the nightside magnetosphere, of large spatial and temporal extent, that can drive large and potentially damaging geomagnetically induced currents (GICs) in terrestrial power grids. Since ground dB/dt can be used as a GIC proxy, we have surveyed GOES data since 2011 for the largest dB/dT events, and found some to be of the order of hundreds of nT in the span of a few seconds. These are observed in both the nightside and dayside, and, as such, we seek to establish connections to drivers affecting both sides of the terminator; tail activations and substorms on the nightside, large amplitude ULF waves, solar wind sudden impulses, and rapid changes in MIC current systems on the dayside. The short duration of these events, coupled with the use of conjugate satellite measurements and ground magnetometer arrays when possible, allows us to investigate their localization and the latitudinal extent of their effects and to further examine the potential role of non-substorm phenomena in generating GICs which may have adverse impacts in electrical power grids.

A feasibility study to estimate minimum surface-casing depths of oil and gas wells to prevent ground-water contamination in four areas of western Pennsylvania

USGS Publications Warehouse

Buckwalter, T.F.; Squillace, P.J.

1995-01-01

Hydrologic data were evaluated from four areas of western Pennsylvania to estimate the minimum depth of well surface casing needed to prevent contamination of most of the fresh ground-water resources by oil and gas wells. The areas are representative of the different types of oil and gas activities and of the ground-water hydrology of most sections of the Appalachian Plateaus Physiographic Province in western Pennsylvania. Approximate delineation of the base of the fresh ground-water system was attempted by interpreting the following hydrologic data: (1) reports of freshwater and saltwater in oil and gas well-completion reports, (2) water well-completion reports, (3) geophysical logs, and (4) chemical analyses of well water. Because of the poor quality and scarcity of ground-water data, the altitude of the base of the fresh ground-water system in the four study areas cannot be accurately delineated. Consequently, minimum surface-casing depths for oil and gas wells cannot be estimated with confidence. Conscientious and reliable reporting of freshwater and saltwater during drilling of oil and gas wells would expand the existing data base. Reporting of field specific conductance of ground water would greatly enhance the value of the reports of ground water in oil and gas well-completion records. Water-bearing zones in bedrock are controlled mostly by the presence of secondary openings. The vertical and horizontal discontinuity of secondary openings may be responsible, in part, for large differences in altitudes of freshwater zones noted on completion records of adjacent oil and gas wells. In upland and hilltop topographies, maximum depths of fresh ground water are reported from several hundred feet below land surface to slightly more than 1,000 feet, but the few deep reports are not substantiated by results of laboratory analyses of dissolved-solids concentrations. Past and present drillers for shallow oil and gas wells commonly install surface casing to below the base of readily observed fresh ground water. Casing depths are selected generally to maximize drilling efficiency and to stop freshwater from entering the well and subsequently interfering with hydrocarbon recovery. The depths of surface casing generally are not selected with ground-water protection in mind. However, on the basis of existing hydrologic data, most freshwater aquifers generally are protected with current casing depths. Minimum surface-casing depths for deep gas wells are prescribed by Pennsylvania Department of Environmental Resources regulations and appear to be adequate to prevent ground-water contamination, in most respects, for the only study area with deep gas fields examined in Crawford County.

30 CFR 75.801 - Grounding resistors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... volts under fault conditions. The grounding resistor shall be rated for maximum fault current continuously and insulated from ground for a voltage equal to the phase-to-phase voltage of the system. ...

30 CFR 75.801 - Grounding resistors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... volts under fault conditions. The grounding resistor shall be rated for maximum fault current continuously and insulated from ground for a voltage equal to the phase-to-phase voltage of the system. ...

Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

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

Kaptan, Y., E-mail: yuecel.kaptan@physik.tu-berlin.de; Herzog, B.; Schöps, O.

2014-11-10

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observedmore » response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.« less

Development of a Portable, Ground-based Ozone Lidar Instrument for Tropospheric Ozone Research and Educational Training

NASA Technical Reports Server (NTRS)

Chyba, Thomas; Zemker, Thomas; Fishman, Jack (Technical Monitor)

1999-01-01

The objective of this research project is to develop a portable, eye-safe, ground-based ozone lidar instrument specialized for ozone differential absorption lidar (DIAL) measurements in the troposphere. This research project directly supports the goal of NASA's Earth Science Enterprise to understand the distribution and budget of tropospheric ozone (objective 1.5 of the Earth Science Strategic Enterprise Plan, 1998-2002). It can participate in ground validation experiments for TES, a tropospheric ozone satellite mission due to be launched in 2002. It can also be utilized for correlative ground measurements in future GTE (Global Tropospheric Experiment) and space-based ozone lidar missions, such as ORACLE. Multiple ground-based ozone lidar systems would improve the data obtained through current ozone-sonde networks. This prototype instrument could to serve as the basic unit for these and other future monitoring projects requiring multi-instrument networks, such as that proposed for the Global Tropospheric Ozone Project (GTOP). GTOP is currently being formulated by a scientific panel of the International Global Atmospheric Chemistry Project to meet its goal to better understand the processes that control the global distribution of tropospheric ozone. In order for the lidar to be widely deployed in networks, it must be fairly easy to use and maintain as well as being cost-competitive with a ground station launching ozonesondes several times a day. A second 2-year grant to continue this effort with students participating in ground tests and system improvements has been awarded by the Office of Equal Employment Opportunities (OEOP). This project also supports existing NASA lidar missions through its development of advanced, compact lidar technology. Innovations in both transmitters and receivers have been made in this project. Finally, this system could be modified in the future to probe more deeply into the stratosphere. This could be accomplished by increasing the emitted energy or optimizing the wavelengths for this purpose. In addition to NASA, this system has applications to the EPA, NOAA, and the DOD. An AFOSR grant has been awarded based on the results of this effort to fund advanced transmitter development at medium (20-40 mJ) energies. A second proposal to the DOD with a letter of support from Air Force Research Laboratory, has been submitted to extend this uv laser technology to 100 mJ levels. Thus, this project has enabled students and faculty at Hampton University to begin to develop research efforts in support of the mission of the DOD. This instrument will be based at Hampton University (HU) to meet our educational goal to train students in lidar technology as well as atmospheric ozone data analysis and interpretation. It will be also available for off-site measurement campaigns and will serve as a test bed for further instrument development. Later development beyond this grant to extend the scientific usefulness of the instrument may include incorporation of an aerosol channel and upgrading the laser to make stratospheric ozone measurements. Seven undergraduates, three graduate students, and one postdoctoral. researcher (formerly an HU student) have been active participants in this research effort.

46 CFR 183.370 - General grounding requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... requirements. (a) A vessel's hull must not carry current as a conductor except for the following systems: (1... more, must have a grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

46 CFR 183.370 - General grounding requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... requirements. (a) A vessel's hull must not carry current as a conductor except for the following systems: (1... more, must have a grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

Biomedical ground lead system

NASA Technical Reports Server (NTRS)

1972-01-01

The design and verification tests for the biomedical ground lead system of Apollo biomedical monitors are presented. Major efforts were made to provide a low impedance path to ground, reduce noise and artifact of ECG signals, and limit the current flowing in the ground electrode of the system.

46 CFR 183.370 - General grounding requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... requirements. (a) A vessel's hull must not carry current as a conductor except for the following systems: (1... more, must have a grounding pole and a grounding conductor in the portable cord. (c) Each nonmetallic mast and top mast must have a lightning ground conductor. ...

Georgia's Ground-Water Resources and Monitoring Network, 2006

USGS Publications Warehouse

Nobles, Patricia L.

2006-01-01

The U.S. Geological Survey (USGS) ground-water network for Georgia currently consists of 170 wells in which ground-water levels are continuously monitored. Most of the wells are locatedin the Coastal Plain in the southern part of the State where ground-water pumping stress is high. In particular, there are large concentrations of wells in coastal and southwestern Georgia areas, where there are issues related to ground-water pumping, saltwater intrusion along the coast, and diminished streamflow in southwestern Georgia due to irrigation pumping. The map at right shows the USGS ground-water monitoring network for Georgia. Ground-water levels are monitored in 170 wells statewide, of which 19 transmit data in real time via satellite and posted on the World Wide Web at http://waterdata.usgs.gov/ga/nwis/current/?type=gw . A greater concentration of wells occurs in the Coastal Plain where there are several layers of aquifers and in coastal and southwestern Georgia areas, which are areas with specific ground-water issues.

Validation of Ground-based Optical Estimates of Auroral Electron Precipitation Energy Deposition

NASA Astrophysics Data System (ADS)

Hampton, D. L.; Grubbs, G. A., II; Conde, M.; Lynch, K. A.; Michell, R.; Zettergren, M. D.; Samara, M.; Ahrns, M. J.

2017-12-01

One of the major energy inputs into the high latitude ionosphere and mesosphere is auroral electron precipitation. Not only does the kinetic energy get deposited, the ensuing ionization in the E and F-region ionosphere modulates parallel and horizontal currents that can dissipate in the form of Joule heating. Global models to simulate these interactions typically use electron precipitation models that produce a poor representation of the spatial and temporal complexity of auroral activity as observed from the ground. This is largely due to these precipitation models being based on averages of multiple satellite overpasses separated by periods much longer than typical auroral feature durations. With the development of regional and continental observing networks (e.g. THEMIS ASI), the possibility of ground-based optical observations producing quantitative estimates of energy deposition with temporal and spatial scales comparable to those known to be exhibited in auroral activity become a real possibility. Like empirical precipitation models based on satellite overpasses such optics-based estimates are subject to assumptions and uncertainties, and therefore require validation. Three recent sounding rocket missions offer such an opportunity. The MICA (2012), GREECE (2014) and Isinglass (2017) missions involved detailed ground based observations of auroral arcs simultaneously with extensive on-board instrumentation. These have afforded an opportunity to examine the results of three optical methods of determining auroral electron energy flux, namely 1) ratio of auroral emissions, 2) green line temperature vs. emission altitude, and 3) parametric estimates using white-light images. We present comparisons from all three methods for all three missions and summarize the temporal and spatial scales and coverage over which each is valid.

Atmosphere-Ionosphere Electrodynamic Coupling

NASA Astrophysics Data System (ADS)

Sorokin, V. M.; Chmyrev, V. M.

Numerous phenomena that occur in the mesosphere, ionosphere, and the magnetosphere of the Earth are caused by the sources located in the lower atmosphere and on the ground. We describe the effects produced by lightning activity and by ground-based transmitters operated in high frequency (HF) and very low frequency (VLF) ranges. Among these phenomena are the ionosphere heating and the formation of plasma density inhomogeneities, the excitation of gamma ray bursts and atmospheric emissions in different spectral bands, the generation of ULF/ELF/VLF electromagnetic waves and plasma turbulence in the ionosphere, the stimulation of radiation belt electron precipitations and the acceleration of ions in the upper ionosphere. The most interesting results of experimental and theoretical studies of these phenomena are discussed below. The ionosphere is subject to the action of the conductive electric current flowing in the atmosphere-ionosphere circuit. We present a physical model of DC electric field and current formation in this circuit. The key element of this model is an external current, which is formed with the occurrence of convective upward transport of charged aerosols and their gravitational sedimentation in the atmosphere. An increase in the level of atmospheric radioactivity results in the appearance of additional ionization and change of electrical conductivity. Variation of conductivity and external current in the lower atmosphere leads to perturbation of the electric current flowing in the global atmosphere-ionosphere circuit and to the associated DC electric field perturbation both on the Earth's surface and in the ionosphere. Description of these processes and some results of the electric field and current calculations are presented below. The seismic-induced electric field perturbations produce noticeable effects in the ionosphere by generating the electromagnetic field and plasma disturbances. We describe the generation mechanisms of such experimentally observed effects as excitation of plasma density inhomogeneities, field-aligned currents, and ULF/ELF emissions and the modification of electron and ion altitude profiles in the upper ionosphere. The electrodynamic model of the ionosphere modification under the influence of some natural and man-made processes in the atmosphere is also discussed. The model is based on the satellite and ground measurements of electromagnetic field and plasma perturbations and on the data on atmospheric radioactivity and soil gas injection into the atmosphere.

A Comparison of Vertical Deformations Derived from Space-based Gravimetry, Ground-based Sensors, and Model-based Hydrologic Loading over the Western United States

NASA Astrophysics Data System (ADS)

Yin, G.; Forman, B. A.; Loomis, B. D.; Luthcke, S. B.

2017-12-01

Vertical deformation of the Earth's crust due to the movement and redistribution of terrestrial freshwater can be studied using satellite measurements, ground-based sensors, hydrologic models, or a combination thereof. This current study explores the relationship between vertical deformation estimates derived from mass concentrations (mascons) from the Gravity Recovery and Climate Experiment (GRACE), vertical deformation from ground-based Global Positioning System (GPS) observations collected from the Plate Boundary Observatory (PBO), and hydrologic loading estimates based on model output from the NASA Catchment Land Surface Model (Catchment). A particular focus is made to snow-dominated basins where mass accumulates during the snow season and subsequently runs off during the ablation season. The mean seasonal cycle and the effects of atmospheric loading, non-tidal ocean loading, and glacier isostatic adjustment (GIA) are removed from the GPS observations in order to derive the vertical displacement caused predominately by hydrological processes. A low-pass filter is applied to GPS observations to remove high frequency noise. Correlation coefficients between GRACE- and GPS-based estimates at all PBO sites are calculated. GRACE-derived and Catchment-derived displacements are subtracted from the GPS height variations, respectively, in order to compute the root mean square (RMS) reduction as a means of studying the consistency between the three different methods. Results show that in most sites, the three methods exhibit good agreement. Exceptions to this generalization include the Central Valley of California where extensive groundwater pumping is witnessed in the GRACE- and GPS-based estimates, but not in the Catchment-based estimates because anthropogenic groundwater pumping activities are not included in the Catchment model. The relatively good agreement between GPS- and GRACE-derived vertical crustal displacements suggests that ground-based GPS has tremendous potential for a Bayesian merger with GRACE-based estimates in order to provide a higher resolution (in space and time) of terrestrial water storage.

A Ground-Based Research Vehicle for Base Drag Studies at Subsonic Speeds

NASA Technical Reports Server (NTRS)

Diebler, Corey; Smith, Mark

2002-01-01

A ground research vehicle (GRV) has been developed to study the base drag on large-scale vehicles at subsonic speeds. Existing models suggest that base drag is dependent upon vehicle forebody drag, and for certain configurations, the total drag of a vehicle can be reduced by increasing its forebody drag. Although these models work well for small projectile shapes, studies have shown that they do not provide accurate predictions when applied to large-scale vehicles. Experiments are underway at the NASA Dryden Flight Research Center to collect data at Reynolds numbers to a maximum of 3 x 10(exp 7), and to formulate a new model for predicting the base drag of trucks, buses, motor homes, reentry vehicles, and other large-scale vehicles. Preliminary tests have shown errors as great as 70 percent compared to Hoerner's two-dimensional base drag prediction. This report describes the GRV and its capabilities, details the studies currently underway at NASA Dryden, and presents preliminary results of both the effort to formulate a new base drag model and the investigation into a method of reducing total drag by manipulating forebody drag.

GLM Proxy Data Generation: Methods for Stroke/Pulse Level Inter-Comparison of Ground-Based Lightning Reference Networks

NASA Technical Reports Server (NTRS)

Cummins, Kenneth L.; Carey, Lawrence D.; Schultz, Christopher J.; Bateman, Monte G.; Cecil, Daniel J.; Rudlosky, Scott D.; Petersen, Walter Arthur; Blakeslee, Richard J.; Goodman, Steven J.

2011-01-01

In order to produce useful proxy data for the GOES-R Geostationary Lightning Mapper (GLM) in regions not covered by VLF lightning mapping systems, we intend to employ data produced by ground-based (regional or global) VLF/LF lightning detection networks. Before using these data in GLM Risk Reduction tasks, it is necessary to have a quantitative understanding of the performance of these networks, in terms of CG flash/stroke DE, cloud flash/pulse DE, location accuracy, and CLD/CG classification error. This information is being obtained through inter-comparison with LMAs and well-quantified VLF/LF lightning networks. One of our approaches is to compare "bulk" counting statistics on the spatial scale of convective cells, in order to both quantify relative performance and observe variations in cell-based temporal trends provided by each network. In addition, we are using microsecond-level stroke/pulse time correlation to facilitate detailed inter-comparisons at a more-fundamental level. The current development status of our ground-based inter-comparison and evaluation tools will be presented, and performance metrics will be discussed through a comparison of Vaisala s Global Lightning Dataset (GLD360) with the NLDN at locations within and outside the U.S.

GLM Proxy Data Generation: Methods for Stroke/Pulse Level Inter-comparison of Ground-based Lightning Reference Networks

NASA Astrophysics Data System (ADS)

Cummins, K. L.; Carey, L. D.; Schultz, C. J.; Bateman, M. G.; Cecil, D. J.; Rudlosky, S. D.; Petersen, W. A.; Blakeslee, R. J.; Goodman, S. J.

2011-12-01

In order to produce useful proxy data for the GOES-R Geostationary Lightning Mapper (GLM) in regions not covered by VLF lightning mapping systems, we intend to employ data produced by ground-based (regional or global) VLF/LF lightning detection networks. Before using these data in GLM Risk Reduction tasks, it is necessary to have a quantitative understanding of the performance of these networks, in terms of CG flash/stroke DE, cloud flash/pulse DE, location accuracy, and CLD/CG classification error. This information is being obtained through inter-comparison with LMAs and well-quantified VLF/LF lightning networks. One of our approaches is to compare "bulk" counting statistics on the spatial scale of convective cells, in order to both quantify relative performance and observe variations in cell-based temporal trends provided by each network. In addition, we are using microsecond-level stroke/pulse time correlation to facilitate detailed inter-comparisons at a more-fundamental level. The current development status of our ground-based inter-comparison and evaluation tools will be presented, and performance metrics will be discussed through a comparison of Vaisala's Global Lightning Dataset (GLD360) with the NLDN at locations within and outside the U.S.

Ability of the current global observing network to constrain N2O sources and sinks

NASA Astrophysics Data System (ADS)

Millet, D. B.; Wells, K. C.; Chaliyakunnel, S.; Griffis, T. J.; Henze, D. K.; Bousserez, N.

2014-12-01

The global observing network for atmospheric N2O combines flask and in-situ measurements at ground stations with sustained and campaign-based aircraft observations. In this talk we apply a new global model of N2O (based on GEOS-Chem) and its adjoint to assess the strengths and weaknesses of this network for quantifying N2O emissions. We employ an ensemble of pseudo-observation analyses to evaluate the relative constraints provided by ground-based (surface, tall tower) and airborne (HIPPO, CARIBIC) observations, and the extent to which variability (e.g. associated with pulsing or seasonality of emissions) not captured by the a priori inventory can bias the inferred fluxes. We find that the ground-based and HIPPO datasets each provide a stronger constraint on the distribution of global emissions than does the CARIBIC dataset on its own. Given appropriate initial conditions, we find that our inferred surface fluxes are insensitive to model errors in the stratospheric loss rate of N2O over the timescale of our analysis (2 years); however, the same is not necessarily true for model errors in stratosphere-troposphere exchange. Finally, we examine the a posteriori error reduction distribution to identify priority locations for future N2O measurements.

Ground Motion Data Profile of Western Turkey with Intelligent Hybrid Processing

NASA Astrophysics Data System (ADS)

Korkmaz, Kasim A.; Demir, Fuat

2017-01-01

The recent earthquakes caused severe damages on the existing buildings. By this motivation, an important amount of research work has been conducted to determine the seismic risk of seismically active regions. For an accurate seismic risk assessment, processing of ground motions would provide an advantage. Using the current technology, it is not possible to precisely predict the future earthquakes. Therefore, most of the current seismic risk assessment methodologies are based on statistical evaluation by using recurrence and magnitude of the earthquakes hit the specified region. Because of the limited number of records on earthquakes, the quality of definitions is questionable. Fuzzy logic algorithm can be used to improve the quality of the definition. In the present study, ground motion data profile of western Turkey is defined using an intelligent hybrid processing. The approach is given in a practical way for an easier and faster calculation. Earthquake data between 1970 and 1999 from western part of Turkey have been used for training. The results are tested and validated with the earthquake data between 2000 and 2015 of the same region. Enough approximation was validated between calculated values and the earthquake data by using the intelligent hybrid processing.

30 CFR 77.902-3 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.902-3 Attachment of ground conductors and ground check wires to... equipment receiving power from resistance grounded systems, separate connections shall be used. ...

30 CFR 77.902-3 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.902-3 Attachment of ground conductors and ground check wires to... equipment receiving power from resistance grounded systems, separate connections shall be used. ...

30 CFR 77.902-3 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.902-3 Attachment of ground conductors and ground check wires to... equipment receiving power from resistance grounded systems, separate connections shall be used. ...

Physics through the 1990s: Gravitation, cosmology and cosmic-ray physics

NASA Technical Reports Server (NTRS)

1986-01-01

The volume contains recommendations for space-and ground-based programs in gravitational physics, cosmology, and cosmic-ray physics. The section on gravitation examines current and planned experimental tests of general relativity; the theory behind, and search for, gravitational waves, including sensitive laser-interferometric tests and other observations; and advances in gravitation theory (for example, incorporating quantum effects). The section on cosmology deals with the big-bang model, the standard model from elementary-particle theory, the inflationary model of the Universe. Computational needs are presented for both gravitation and cosmology. Finally, cosmic-ray physics theory (nucleosynthesis, acceleration models, high-energy physics) and experiment (ground and spaceborne detectors) are discussed.

The solar wind-magnetosphere-ionosphere system

PubMed

Lyon

2000-06-16

The solar wind, magnetosphere, and ionosphere form a single system driven by the transfer of energy and momentum from the solar wind to the magnetosphere and ionosphere. Variations in the solar wind can lead to disruptions of space- and ground-based systems caused by enhanced currents flowing into the ionosphere and increased radiation in the near-Earth environment. The coupling between the solar wind and the magnetosphere is mediated and controlled by the magnetic field in the solar wind through the process of magnetic reconnection. Understanding of the global behavior of this system has improved markedly in the recent past from coordinated observations with a constellation of satellite and ground instruments.

Efficient cooling of quantized vibrations using a four-level configuration

NASA Astrophysics Data System (ADS)

Yan, Lei-Lei; Zhang, Jian-Qi; Zhang, Shuo; Feng, Mang

2016-12-01

Cooling vibrational degrees of freedom down to ground states is essential to observation of quantum properties of systems with mechanical vibration. We propose two cooling schemes employing four internal levels of the systems, which achieve the ground-state cooling in an efficient fashion by completely deleting the carrier and first-order blue-sideband transitions. The schemes, based on quantum interference and Stark-shift gates, are robust to fluctuations of laser intensity and frequency. The feasibility of the schemes is justified using current laboratory technology. In practice, our proposal readily applies to a nanodiamond nitrogen-vacancy center levitated in an optical trap or attached to a cantilever.

Invited Talk: Photometry of Bright Variable Stars with the BRITE Constellation Nano-Satellites: Opportunities for Amateur Astronomers

NASA Astrophysics Data System (ADS)

Guinan, E. F.

2014-06-01

(Abstract only) The BRIght Target Explorer (BRITE) is a joint Austrian-Canadian-Polish Astronomy mission to carry out high precision photometry of bright (mv < 4 mag.) variable stars. BRITE consists of a "Constellation" of 20 × 20 × 20-cm nano-satellite cubes equipped with wide field (20 × 24 deg.) CCD cameras, control systems, solar panels, onboard computers, and so on. The first two (of up to six) satellites were successfully launched during February 2013. After post-launch commissioning, science operations commenced during October 2013. The primary goals are to carry out continuous multi-color (currently blue and red filters) high-precision millimag (mmag) photometry in particular locations in the sky. Typically these pointings will last for two to four months and secure simultaneous blue/red photometry of bright variable stars within the field. The first science pointing is centered on the Orion region. Since most bright stars are intrinsically luminous, hot O/B stars, giants, and supergiants will be the most common targets. However, some bright eclipsing binaries (such as Algol, b Lyr, e Aur) and a few chromospherically-active RS CVn stars (such as Capella) may be eventually be monitored. The BRITE-Constellation program of high precision, two color photometry of bright stars offers a great opportunity to study a wide range of stellar astrophysical problems. Bright stars offer convenient laboratories to study many current and important problems in stellar astrophysics. These include probing stellar interiors and pulsation in pulsating stars, tests of stellar evolution and structure for Cepheids and other luminous stars. To scientifically enhance the BRITE science returns, the BRITE investigators are very interested in securing contemporaneous ground-based spectroscopy and standardized photometry of target stars. The BRITE Ground Based Observations Team is coordinating ground-based observing efforts for BRITE targets. The team helps coordinate collaborations with amateur and professional astronomer. The ground-based coordinators are: Thomas Eversberg (thomas.eversberg@dlr.de) and, for spectroscopy, Contanze Zwintz (konstanze@ster.kuleuven.be). Detailed information about the BRITE Mission is provided at: www.brite-contellation.at.

Ground- and Space-based Observations of Horizontally-extensive Lightning Flashes

NASA Astrophysics Data System (ADS)

Zhang, D.; Cummins, K. L.; Bitzer, P. M.

2017-12-01

Horizontally-extensive lightning flashes occur frequently in association with mature and late phases of multicellular thunderstorms, both in trailing stratiform regions and horizontally-extensive anvils. The spatial relationship between these flashes and the parent cloud volume is of importance for space launch operational decision making, and is of broader scientific interest. Before this question can be accurately addressed, there is a need to understand the degree to which current lightning observation systems can depict the spatial extent of these long flashes. In this ongoing work, we will intercompare the depiction of horizontally-extensive flashes using several ground-based lightning locating systems (LLSs) located at Kennedy Space Center (KSC) with space-based observations observed by the recently-launched Geostationary Lightning Mapper (GLM) onboard the GOES-16 satellite. Ground-based datasets include the KSC Lightning Mapping Array (KSCLMA), the operational narrowband digital interferometer network MERLIN, and the combined cloud-to-ground and cloud lightning dataset produced by the U.S. National Lightning Detection Network (NLDN). The KSCLMA system is a network of VHF time-of-arrival sensors that preferentially report breakdown processes, and MERLIN is a network of VHF interferometers that point to the discharges in the horizontal plane. Observations to date indicate that MERLIN and the KSCSLMA provide similar overall descriptions of the spatial and temporal extent of these flashes, while the NLDN does not provide adequate spatial mapping of these flashes. The KSC LMA system has much better location accuracy, and provides excellent 3-dimensional representation within 100 km of KSC. It also has sufficient sensitivity to provide 2-dimensional flash mapping within 250 km of KSC. The MERLIN system provides a more-detailed representation of fast leader propagation (in 2 dimensions) with 100 km of KSC. Earlier work during the CHUVA campaign in Brazil with similar systems and the (orbital) Lightning Imaging System (LIS) has shown that the interferometric data correlated much better in space and time with the LIS optical observations. We are currently investigating this relationship at KSC, where both the LMA and interferometer perform much better than the systems used during CHUVA.

Pulsed Artificial Electrojet Generation

NASA Astrophysics Data System (ADS)

Papadopoulos, K.

2008-12-01

Traditional techniques for generating low frequency signals in the ULF/ELF range (.1-100 Hz) and rely on ground based Horizontal Electric Dipole (HED) antennas. It is, furthermore, well known that a Vertical Electric Dipole (VED) is by more than 50 dB more efficient than a HED with the same dipole current moment. However, the prohibitively long length of VED antennas in the ELF/ULF range coupled with voltage limitations due to corona discharge in the atmosphere make them totally impracticable. In this paper we discuss a novel concept, inspired by the physics of the equatorial electrojet, that allows for the conversion of a ground based HED to a VED in the E-region of the equatorial ionosphere with current moment comparable to the driving HED. The paper focuses in locations near the dip-equator, where the earth's magnetic is in predominantly in the horizontal direction. The horizontal electric field associated with a pulsed HED drives a large Hall current in the ionospheric E-region, resulting in a vertical current. It is shown that the pulsed vertical current in the altitude range 80-130 km, driven by a horizontal electric field of, approximately, .1 mV/m at 100 km altitude, is of the order of kA. This results in a pulsed VED larger than 106 A-m. Such a pulsed VED will drive ELF/ULF pulses with amplitude in excess of .1 nT at a lateral range larger than few hundred kilometers. This is by three orders of magnitude larger than the one expected by a HED with comparable current moment. The paper will conclude with the description of a sneak-through technique that allows for creating pulsed electric fields in the ionosphere much larger than expected from steady state oscillatory HED antennas.

EMP on a NTS experiment

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

Gilbert, J.; van Lint, V.; Sherwood, S.

This report is a compilation of two previous sets of pretest calculations, references 1 and 2 and the grounding and shielding report, reference 3. The calculations performed in reference 1 were made for the baseline system, with the instrumentation trailers not isolated from ground, and wider ranges of ground conductivity were considered. This was used to develop the grounding and shielding plan included in the appendix. The final pretest calculations of reference 2 were performed for the modified system with isolated trailers, and with a better knowledge of the ground conductivity. The basic driving mechanism for currents in the modelmore » is the motion of Compton electrons, driven by gamma rays, in the air gaps and soil. Most of the Compton current is balanced by conduction current which returns directly along the path of the Compton electron, but a small fraction will return by circuitous paths involving current flow on conductors, including the uphole cables. The calculation of the currents is done in a two step process -- first the voltages in the ground near the conducting metallic structures is calculated without considering the presence of the structures. These are then used as open circuit drivers for an electrical model of the conductors which is obtained from loop integrals of Maxwell`s equations. The model which is used is a transmission line model, similar to those which have been used to calculate EMP currents on buried and overhead cables in other situations, including previous underground tests, although on much shorter distance and time scales, and with more controlled geometries. The behavior of air gaps between the conducting structure and the walls of the drift is calculated using an air chemistry model which determines the electron and ion densities and uses them to calculate the air conductivity across the gap.« less

Simulation of the Regional Ground-Water-Flow System and Ground-Water/Surface-Water Interaction in the Rock River Basin, Wisconsin

USGS Publications Warehouse

Juckem, Paul F.

2009-01-01

A regional, two-dimensional, areal ground-water-flow model was developed to simulate the ground-water-flow system and ground-water/surface-water interaction in the Rock River Basin. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Rock River Coalition. The objectives of the regional model were to improve understanding of the ground-water-flow system and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate ground-water/surface-water interactions, provide a framework for simulating regional ground-water-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate ground-water-flow patterns at multiple scales. The ground-water-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, ground-water/surface-water interactions, and ground-water withdrawals from high-capacity wells. The steady-state model treats the ground-water-flow system as a single layer with hydraulic conductivity and base elevation zones that reflect the distribution of lithologic groups above the Precambrian bedrock and a regionally significant confining unit, the Maquoketa Formation. In the eastern part of the Basin where the shale-rich Maquoketa Formation is present, deep ground-water flow in the sandstone aquifer below the Maquoketa Formation was not simulated directly, but flow into this aquifer was incorporated into the GFLOW model from previous work in southeastern Wisconsin. Recharge was constrained primarily by stream base-flow estimates and was applied uniformly within zones guided by regional infiltration estimates for soils. The model includes average ground-water withdrawals from 1997 to 2006 for municipal wells and from 1997 to 2005 for high-capacity irrigation, industrial, and commercial wells. In addition, the model routes tributary base flow through the river network to the Rock River. The parameter-estimation code PEST was linked to the GFLOW model to select the combination of parameter values best able to match more than 8,000 water-level measurements and base-flow estimates at 9 streamgages. Results from the calibrated GFLOW model show simulated (1) ground-water-flow directions, (2) ground-water/surface-water interactions, as depicted in a map of gaining and losing river and lake sections, (3) ground-water contributing areas for selected tributary rivers, and (4) areas of relatively local ground water captured by rivers. Ground-water flow patterns are controlled primarily by river geometries, with most river sections gaining water from the ground-water-flow system; losing sections are most common on the downgradient shore of lakes and reservoirs or near major pumping centers. Ground-water contributing areas to tributary rivers generally coincide with surface watersheds; however the locations of ground-water divides are controlled by the water table, whereas surface-water divides are controlled by surface topography. Finally, areas of relatively local ground water captured by rivers generally extend upgradient from rivers but are modified by the regional flow pattern, such that these areas tend to shift toward regional ground-water divides for relatively small rivers. It is important to recognize the limitations of this regional-scale model. Heterogeneities in subsurface properties and in recharge rates are considered only at a very broad scale (miles to tens of miles). No account is taken of vertical variations in properties or pumping rates, and no provision is made to account for stacked ground-water-flow systems that have different flow patterns at different depths. Small-scale flow systems (hundreds to thousands of feet) associated with minor water bodies are not considered; as a result, the model is not currently designed for simulating site-specifi

Autonomous aerial observations to extend and complement the Earth Observing System: a science-driven systems-oriented approach

NASA Astrophysics Data System (ADS)

Sandford, Stephen P.; Harrison, F. W.; Langford, John; Johnson, James W.; Qualls, Garry; Emmitt, David; Jones, W. Linwood; Shugart, Herman H., Jr.

2004-12-01

The current Earth observing capability depends primarily on spacecraft missions and ground-based networks to provide the critical on-going observations necessary for improved understanding of the Earth system. Aircraft missions play an important role in process studies but are limited to relatively short-duration flights. Suborbital observations have contributed to global environmental knowledge by providing in-depth, high-resolution observations that space-based and in-situ systems are challenged to provide; however, the limitations of aerial platforms - e.g., limited observing envelope, restrictions associated with crew safety and high cost of operations have restricted the suborbital program to a supporting role. For over a decade, it has been recognized that autonomous aerial observations could potentially be important. Advances in several technologies now enable autonomous aerial observation systems (AAOS) that can provide fundamentally new observational capability for Earth science and applications and thus lead scientists and engineers to rethink how suborbital assets can best contribute to Earth system science. Properly developed and integrated, these technologies will enable new Earth science and operational mission scenarios with long term persistence, higher-spatial and higher-temporal resolution at lower cost than space or ground based approaches. This paper presents the results of a science driven, systems oriented study of broad Earth science measurement needs. These needs identify aerial mission scenarios that complement and extend the current Earth Observing System. These aerial missions are analogous to space missions in their complexity and potential for providing significant data sets for Earth scientists. Mission classes are identified and presented based on science driven measurement needs in atmospheric, ocean and land studies. Also presented is a nominal concept of operations for an AAOS: an innovative set of suborbital assets that complements and augments current and planned space-based observing systems.

The Uses and Applications of Learning Technologies in the Modern Classroom: Finding a Common Ground Between Kinaesthetic and Theoretical Delivery.

ERIC Educational Resources Information Center

Glass, Samuel

Under the old system of trade skills education, instruction was delivered largely through kinesthetic methods. Currently, however, secondary and postsecondary trade skills education programs institutions in Australia and elsewhere are changing their educational emphasis from traditional skills to more technology-based skills. This shift raises the…

Muscular Proprioception Contributes to the Control of Interceptive Actions

ERIC Educational Resources Information Center

Bastin, Julien; Calvin, Sarah; Montagne, Gilles

2006-01-01

The authors proposed a model of the control of interceptive action over a ground plane (Chardenon, Montagne, Laurent, & Bootsma, 2004). This model is based on the cancellation of the rate of change of the angle between the current position of the target and the direction of displacement (i.e., the bearing angle). While several sources of visual…

Developing and refining NIR calibrations for total carbohydrate composition and isoflavones and saponins in ground whole soy meal

USDA-ARS?s Scientific Manuscript database

Although many near infrared (NIR) spectrometric calibrations exist for a variety of components in soy, current calibration methods are often limited by either a small sample size on which the calibrations are based or a wide variation in sample preparation and measurement methods, which yields unrel...

The Status of Secondary Science Education in the United States: Factors That Predict Practice

ERIC Educational Resources Information Center

Smith, Adrienne A.; Banilower, Eric R.; Nelson, Michele M.; Smith, P. Sean

2013-01-01

New K-12 science education standards emphasize teaching and learning grounded in authentic scientific practices. A first step toward supporting teachers' adoption of scientific practice-based pedagogies is to develop a clear picture of how teachers are currently teaching science, and what factors predict their pedagogical choices. A recently…

Integrating Art into Group Treatment for Adults with Post-Traumatic Stress Disorder from Childhood Sexual Abuse: A Pilot Study

ERIC Educational Resources Information Center

Becker, Carol-Lynne J.

2015-01-01

Current research supports the use of exposure-based treatments for posttraumatic stress disorder (PTSD) and integrated treatments show potential for enhanced symptom reduction. This pilot study developed a manualized group treatment integrating art interventions with exposure, grounding, and narrative therapy for five adults with PTSD who were…

Improving Behavior through Differential Reinforcement: A Praise Note System for Elementary School Students

ERIC Educational Resources Information Center

Wheatley, Rikki K.; West, Richard P.; Charlton, Cade T.; Sanders, Richard B.; Smith, Tim G.; Taylor, Matthew J.

2009-01-01

Schools are often in need of low-cost, high-impact strategies to improve student behavior in school common areas. While many behavior management programs exist, there are few resources available to guide the implementation of these programs and ensure they are grounded in evidence-based strategies. Therefore, the current study had two primary…

Emissions from prescribed burning of agricultural fields in the Pacific Northwest

Treesearch

A. L. Holder; B. K. Gullett; S. P. Urbanski; R. Elleman; S. O' Neill; D. Tabor; W. Mitchell; K. R. Baker

2017-01-01

Prescribed burns of winter wheat stubble and Kentucky bluegrass fields in northern Idaho and eastern Washington states (U.S.A.) were sampled using ground-, aerostat-, airplane-, and laboratory-based measurement platforms to determine emission factors, compare methods, and provide a current and comprehensive set of emissions data for air quality models, climate models,...

77 FR 457 - Implementation of Statute of Limitations Provisions for Office Disciplinary Proceedings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-05

... OED Director seeks the practitioner's side of the story, if at all, only after the OED Director... possible grounds for discipline, the OED Director seeks the practitioner's side of the story--the second... practitioner has had the opportunity to present his or her side of the story. Based on current caseload and...

78 FR 45104 - Model Manufactured Home Installation Standards: Ground Anchor Installations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-26

... test methods for establishing working load design values of ground anchor assemblies used for new... anchor installations and establish standardized test methods to determine ground anchor performance and... currently no national test method for rating and certifying ground anchor assemblies in different soil...

30 CFR 75.902-1 - Maximum voltage ground check circuits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maximum voltage ground check circuits. 75.902-1... Alternating Current Circuits § 75.902-1 Maximum voltage ground check circuits. The maximum voltage used for such ground check circuits shall not exceed 40 volts. ...

30 CFR 75.902-1 - Maximum voltage ground check circuits.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Maximum voltage ground check circuits. 75.902-1... Alternating Current Circuits § 75.902-1 Maximum voltage ground check circuits. The maximum voltage used for such ground check circuits shall not exceed 40 volts. ...

Estimating the potential biodiversity impact of redeveloping small urban spaces: the Natural History Museum’s grounds

PubMed Central

Knapp, Sandra; Purvis, Andy

2017-01-01

Background With the increase in human population, and the growing realisation of the importance of urban biodiversity for human wellbeing, the ability to predict biodiversity loss or gain as a result of land use change within urban settings is important. Most models that link biodiversity and land use are at too coarse a scale for informing decisions, especially those related to planning applications. Using the grounds of the Natural History Museum, London, we show how methods used in global models can be applied to smaller spatial scales to inform urban planning. Methods Data were extracted from relevant primary literature where species richness had been recorded in more than one habitat type within an urban setting. As within-sample species richness will increase with habitat area, species richness estimates were also converted to species density using theory based on the species–area relationship. Mixed-effects models were used to model the impact on species richness and species density of different habitat types, and to estimate these metrics in the current grounds and under proposed plans for redevelopment. We compared effects of three assumptions on how within-sample diversity scales with habitat area as a sensitivity analysis. A pre-existing database recording plants within the grounds was also used to estimate changes in species composition across different habitats. Results Analysis estimated that the proposed plans would result in an increase of average biodiversity of between 11.2% (when species density was modelled) and 14.1% (when within-sample species richness was modelled). Plant community composition was relatively similar between the habitats currently within the grounds. Discussion The proposed plans for change in the NHM grounds are estimated to result in a net gain in average biodiversity, through increased number and extent of high-diversity habitats. In future, our method could be improved by incorporating purposefully collected ecological survey data (if resources permit) and by expanding the data sufficiently to allow modelling of the temporal dynamics of biodiversity change after habitat disturbance and creation. Even in its current form, the method produces transparent quantitative estimates, grounded in ecological data and theory, which can be used to inform relatively small scale planning decisions. PMID:29104821

49 CFR 236.107 - Ground tests.

Code of Federal Regulations, 2012 CFR

2012-10-01

... alternating current power distribution circuits grounded in the interest of safety. [49 FR 3384, Jan. 26, 1984] ... paragraph (b) of this section, a test for grounds on each energy bus furnishing power to circuits, the...

49 CFR 236.107 - Ground tests.

Code of Federal Regulations, 2013 CFR

2013-10-01

... alternating current power distribution circuits grounded in the interest of safety. [49 FR 3384, Jan. 26, 1984] ... paragraph (b) of this section, a test for grounds on each energy bus furnishing power to circuits, the...

Statistical Forecasting of Current and Future Circum-Arctic Ground Temperatures and Active Layer Thickness

NASA Astrophysics Data System (ADS)

Aalto, J.; Karjalainen, O.; Hjort, J.; Luoto, M.

2018-05-01

Mean annual ground temperature (MAGT) and active layer thickness (ALT) are key to understanding the evolution of the ground thermal state across the Arctic under climate change. Here a statistical modeling approach is presented to forecast current and future circum-Arctic MAGT and ALT in relation to climatic and local environmental factors, at spatial scales unreachable with contemporary transient modeling. After deploying an ensemble of multiple statistical techniques, distance-blocked cross validation between observations and predictions suggested excellent and reasonable transferability of the MAGT and ALT models, respectively. The MAGT forecasts indicated currently suitable conditions for permafrost to prevail over an area of 15.1 ± 2.8 × 106 km2. This extent is likely to dramatically contract in the future, as the results showed consistent, but region-specific, changes in ground thermal regime due to climate change. The forecasts provide new opportunities to assess future Arctic changes in ground thermal state and biogeochemical feedback.

Base of Principal Aquifer for the Elkhorn-Loup Model Area, North-Central Nebraska

USGS Publications Warehouse

McGuire, V.L.; Peterson, Steven M.

2008-01-01

In Nebraska, the water managers in the Natural Resources Districts and the Nebraska Department of Natural Resources are concerned with the effect of ground-water withdrawal on the availability of surface water and the long-term effects of ground-water withdrawal on ground- and surface-water resources. In north-central Nebraska, in the Elkhorn and Loup River Basins, ground water is used for irrigation, domestic supply, and public supply; surface water is used in this area for irrigation, recreation, and hydropower production. In recognition of these sometimes competing ground- and surface-water uses in the Elkhorn and Loup River Basins, the U.S. Geological Survey, the Lewis and Clark Natural Resources District, the Lower Elkhorn Natural Resources District, the Lower Loup Natural Resources District, the Lower Niobrara Natural Resources District, the Lower Platte North Natural Resources District, the Middle Niobrara Natural Resources District, the Upper Elkhorn Natural Resources District, and the Upper Loup Natural Resources District agreed to cooperatively study water resources in the Elkhorn and Loup River Basins. The goals of the overall study were to construct and calibrate a regional ground-water flow model of the area and to use that flow model as a tool to assess current and future effects of ground-water irrigation on stream base flow and to help develop long-term water-resource management strategies for this area, hereafter referred to as the Elkhorn-Loup model area. The Elkhorn-Loup model area covers approximately 30,800 square miles, and extends from the Niobrara River in the north to the Platte River in the south. The western boundary of the Elkhorn-Loup model area coincides with the western boundary of the Middle Niobrara, Twin Platte, and Upper Loup Natural Resources Districts; the eastern boundary coincides with the approximate location of the western extent of glacial till in eastern Nebraska. The principal aquifer in most of the Elkhorn-Loup model area is the High Plains aquifer; the principal aquifer in the remaining part of the Elkhorn-Loup model area is an unnamed alluvial aquifer. The upper surface of the geologic units that directly underlie the aquifer is called the 'base of aquifer' in this report. The geologic unit that forms the base of aquifer in the Elkhorn-Loup model area varies by location. The Tertiary-age Brule Formation generally is the base of aquifer in the west; the Cretaceous-age Pierre Shale generally is the base of aquifer in the east. The purpose of this report is to update the altitude and configuration of the base of the principal aquifer in the Elkhorn-Loup model area and a 2-mile buffer area around the Elkhorn-Loup model area, using base-of-aquifer data from test holes, registered water wells, and oil and gas wells within the Elkhorn-Loup model area and a 20-mile buffer area around the Elkhorn-Loup model area that have become available since the publication of earlier maps of the base of aquifer for this area. The base-of-aquifer map is important for the Elkhorn-Loup ground-water flow model because it defines the model's lower boundary. The accuracy of the Elkhorn-Loup ground-water flow model and the accuracy of the model's predictions about the effects of ground-water irrigation on stream base flow are directly related to the accuracy of the model's lower boundary.

Density-functional theory for internal magnetic fields

NASA Astrophysics Data System (ADS)

Tellgren, Erik I.

2018-01-01

A density-functional theory is developed based on the Maxwell-Schrödinger equation with an internal magnetic field in addition to the external electromagnetic potentials. The basic variables of this theory are the electron density and the total magnetic field, which can equivalently be represented as a physical current density. Hence, the theory can be regarded as a physical current density-functional theory and an alternative to the paramagnetic current density-functional theory due to Vignale and Rasolt. The energy functional has strong enough convexity properties to allow a formulation that generalizes Lieb's convex analysis formulation of standard density-functional theory. Several variational principles as well as a Hohenberg-Kohn-like mapping between potentials and ground-state densities follow from the underlying convex structure. Moreover, the energy functional can be regarded as the result of a standard approximation technique (Moreau-Yosida regularization) applied to the conventional Schrödinger ground-state energy, which imposes limits on the maximum curvature of the energy (with respect to the magnetic field) and enables construction of a (Fréchet) differentiable universal density functional.

The substorm current reconfiguration scenario and related observations in the magnetic field and thermosphere

NASA Astrophysics Data System (ADS)

Ritter, Patricia; Luehr, Hermann

The input of energy and momentum from the magnetosphere is most efficiently coupled into the high latitude ionosphere-thermosphere during magnetospheric substorms. This paper presents substorm related observations of the magnetic field on ground and by the CHAMP satellite, their implications for the substorm current reconfiguration scenario, and thermospheric air density signatures after substorm onsets. Based on a large number of events, the average high and low latitude magnetic field signatures after substorm onsets reveal that the magnetic field observations cannot be described adequately by a simple current wedge model. A satisfactory agreement between model results and observations at satellite altitude and on ground can be achieved only if the current reconfiguration scenario combines the following four elements: (1) a gradual decrease of the tail lobe field; (2) a re-routing of a part of the cross-tail current through the ionosphere; (3) eastward ionospheric currents at low and mid latitudes driven by Region-2 field-aligned currents (FACs); and (4) a partial ring current connected to these Region-2 FACs. With the onset of energy input into the ionosphere we observe that the thermospheric density is enhanced first at high latitudes on the night side. The disturbance then travels at an average speed of 650 m/s to lower latitudes, and reaches the equator after 3-4 hours. Under the influence of the Coriolis force the traveling atmospheric disturbance (TAD) is deflected westward.

GOSAT-2 : Science Plan, Products, Validation, and Application

NASA Astrophysics Data System (ADS)

Matsunaga, T.; Morino, I.; Yoshida, Y.; Saito, M.; Hiraki, K.; Yokota, Y.; Kamei, A.; Oishi, Y.; Dupuy, E.; Murakami, K.; Ninomiya, K.; Pang, J. S.; Yokota, T.; Maksyutov, S. S.; Machida, T.; Saigusa, N.; Mukai, H.; Nakajima, M.; Imasu, R.; Nakajima, T.

2013-12-01

Based on the success of Greenhouse Gases Observing Satellite (GOSAT) launched in 2009, Ministry of the Environment (MOE), Japan Space Exploration Agency (JAXA), and National Institute for Environmental Studies (NIES) started the preparations for the follow-on satellite, GOSAT-2 in FY2011. The current target launch year of GOSAT-2 is FY2017. The objectives of GOSAT-2 include : 1) Continue and enhance spaceborne greenhouse gases observation started by GOSAT, 2) Improve our understanding of global and regional carbon cycles, and 3) Contribute to the climate change related policies as one of MRV(Measurement, Reporting, and Verification) tools for carbon emission reduction. As a scientific background/rationale of GOSAT-2, GOSAT-2 Science Plan is being edited by GOSAT-2 Science Team Preparation Committee. Not only carbon dioxide and methane but also carbon monoxide, tropospheric ozone, and aerosols are discussed in the plan. GOSAT-2 Level 2 (gas concentrations) and Level 4 (gas fluxes) products will be operationally generated at and distributed from GOSAT-2 Data Handling Facility located in NIES. In addition, a new supercomputer dedicated to GOSAT-2 research and development will be also installed in NIES. GOSAT-2 validation plan is also being discussed. Its baseline is similar to the current GOSAT . But various efforts will be made to extend the coverage of validation data for GOSAT-2. The efforts include the increased commercial passenger aircraft volunteering atmospheric measurements and additional ground-based Fourier transform spectrometers to be newly installed in Asian countries. In addition, a compact accelerator mass spectrometer is being introduced to NIES to investigate the contributions of anthropogenic emissions which is important for GOSAT-2. Climate change related policies include JCM (Joint Crediting Mechanism) in which MRV plays a critical role. MRV tools used in the existing JCM projects are mostly ground-based and site-specific. Satellite atmospheric measurements such as GOSAT or GOSAT-2 are expected to be more general and independent MRV tools and complement ground-based tools. The current status of GOSAT-2 science plan, products, validation, and application will be shown in the presentation.

UAS-Borne Photogrammetry for Surface Topographic Characterization: A Ground-Truth Baseline for Future Change Detection and Refinement of Scaled Remotely-Sensed Datasets

NASA Astrophysics Data System (ADS)

Coppersmith, R.; Schultz-Fellenz, E. S.; Sussman, A. J.; Vigil, S.; Dzur, R.; Norskog, K.; Kelley, R.; Miller, L.

2015-12-01

While long-term objectives of monitoring and verification regimes include remote characterization and discrimination of surficial geologic and topographic features at sites of interest, ground truth data is required to advance development of remote sensing techniques. Increasingly, it is desirable for these ground-based or ground-proximal characterization methodologies to be as nimble, efficient, non-invasive, and non-destructive as their higher-altitude airborne counterparts while ideally providing superior resolution. For this study, the area of interest is an alluvial site at the Nevada National Security Site intended for use in the Source Physics Experiment's (Snelson et al., 2013) second phase. Ground-truth surface topographic characterization was performed using a DJI Inspire 1 unmanned aerial system (UAS), at very low altitude (< 5-30m AGL). 2D photographs captured by the standard UAS camera payload were imported into Agisoft Photoscan to create three-dimensional point clouds. Within the area of interest, careful installation of surveyed ground control fiducial markers supplied necessary targets for field collection, and information for model georectification. The resulting model includes a Digital Elevation Model derived from 2D imagery. It is anticipated that this flexible and versatile characterization process will provide point cloud data resolution equivalent to a purely ground-based LiDAR scanning deployment (e.g., 1-2cm horizontal and vertical resolution; e.g., Sussman et al., 2012; Schultz-Fellenz et al., 2013). In addition to drastically increasing time efficiency in the field, the UAS method also allows for more complete coverage of the study area when compared to ground-based LiDAR. Comparison and integration of these data with conventionally-acquired airborne LiDAR data from a higher-altitude (~ 450m) platform will aid significantly in the refinement of technologies and detection capabilities of remote optical systems to identify and detect surface geologic and topographic signatures of interest. This work includes a preliminary comparison of surface signatures detected from varying standoff distances to assess current sensor performance and benefits.

Summary of the hydrogeology of the Valley and Ridge, Blue Ridge, and Piedmont Physiographic Provinces in the eastern United States

USGS Publications Warehouse

Swain, Lindsay A.; Mesko, Thomas O.; Hollyday, Este F.

2004-01-01

The Appalachian Valley and Piedmont Regional Aquifer-System Analysis study (1988-1993) analyzed rock types in the 142,000-square-mile study area, identified hydrogeologic terranes, determined transmissivity distributions, determined the contribution of ground water to streamflow, modeled ground-water flow, described water quality, and identified areas suitable for the potential development of municipal and industrial ground-water supplies. Ground-water use in the Valley and Ridge, the Blue Ridge, and the Piedmont Physiographic Provinces exceeds 1.7 billion gallons per day.Thirty-three rock types in the study area were analyzed, and the rock types with similar water-yielding characteristics were combined and mapped as 10 hydrogeologic terranes. Based on well records, the interquartile ranges of estimated transmissivities are between 180 to 17,000 feet squared per day (ft2/d) for five hydrologic terranes in the Valley and Ridge; between 9 to 350 ft2/d for two terranes in the Blue Ridge; and between 9 to 1,400 ft2/d for three terranes in the Piedmont Physiographic Province. Based on streamflow records, the interquartile ranges of estimated transmissivities for all three physiographic provinces are between 290 and 2,900 ft2/d. The mean ground-water contribution to streams from 157 drainage basins ranges from 32 to 94 percent of mean streamflow with a median of 67 percent. In three small areas in two of the physiographic provinces, more than 54 percent of ground-water flow was modeled as shallow and local. Although ground-water chemical composition in the three physiographic provinces is distinctly different, the water generally is not highly mineralized, with a median dissolved-solids concentration of 164 milligrams per liter, and is mostly calcium, magnesium, and bicarbonate. Based on aquifer properties and current pumpage, areas favorable for the development of municipal and industrial ground-water supplies are underlain by alluvium of glacial origin near the northeastern part of the study area, by clay-free carbonate rocks primarily in the Valley and Ridge Physiographic Province, and by siliciclastic rocks in the three northernmost Mesozoic basins.

Modeling Current Transfer from PV Modules Based on Meteorological Data

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

Hacke, Peter; Smith, Ryan; Kurtz, Sarah

2016-11-21

Current transferred from the active cell circuit to ground in modules undergoing potential-induced degradation (PID) stress is analyzed with respect to meteorological data. Duration and coulombs transferred as a function of whether the module is wet (from dew or rain) or the extent of uncondensed surface humidity are quantified based on meteorological indicators. With this, functions predicting the mode and rate of coulomb transfer are developed for use in estimating the relative PID stress associated with temperature, moisture, and system voltage in any climate. Current transfer in a framed crystalline silicon module is relatively high when there is no condensedmore » water on the module, whereas current transfer in a thin-film module held by edge clips is not, and displays a greater fraction of coulombs transferred when wet compared to the framed module in the natural environment.« less

Altair Navigation During Trans-Lunar Cruise, Lunar Orbit, Descent and Landing

NASA Technical Reports Server (NTRS)

Ely, Todd A.; Heyne, Martin; Riedel, Joseph E.

2010-01-01

The Altair lunar lander navigation system is driven by a set of requirements that not only specify a need to land within 100 m of a designated spot on the Moon, but also be capable of a safe return to an orbiting Orion capsule in the event of loss of Earth ground support. These requirements lead to the need for a robust and capable on-board navigation system that works in conjunction with an Earth ground navigation system that uses primarily ground-based radiometric tracking. The resulting system relies heavily on combining a multiplicity of data types including navigation state updates from the ground based navigation system, passive optical imaging from a gimbaled camera, a stable inertial measurement unit, and a capable radar altimeter and velocimeter. The focus of this paper is on navigation performance during the trans-lunar cruise, lunar orbit, and descent/landing mission phases with the goal of characterizing knowledge and delivery errors to key mission events, bound the statistical delta V costs for executing the mission, as well as the determine the landing dispersions due to navigation. This study examines the nominal performance that can be obtained using the current best estimate of the vehicle, sensor, and environment models. Performance of the system under a variety sensor outages and parametric trades is also examined.

Evolution of the current system during solar wind pressure pulses based on aurora and magnetometer observations

NASA Astrophysics Data System (ADS)

Nishimura, Yukitoshi; Kikuchi, Takashi; Ebihara, Yusuke; Yoshikawa, Akimasa; Imajo, Shun; Li, Wen; Utada, Hisashi

2016-08-01

We investigated evolution of ionospheric currents during sudden commencements using a ground magnetometer network in conjunction with an all-sky imager, which has the advantage of locating field-aligned currents much more accurately than ground magnetometers. Preliminary (PI) and main (MI) impulse currents showed two-cell patterns propagating antisunward, particularly during a southward interplanetary magnetic field (IMF). Although this overall pattern is consistent with the Araki (solar wind sources of magnetospheric ultra-low-frequency waves. Geophysical monograph series, vol 81. AGU, Washington, DC, pp 183-200, 1994. doi: 10.1029/GM081p0183) model, we found several interesting features. The PI and MI currents in some events were highly asymmetric with respect to the noon-midnight meridian; the post-noon sector did not show any notable PI signal, but only had an MI starting earlier than the pre-noon MI. Not only equivalent currents but also aurora and equatorial magnetometer data supported the much weaker PI response. We suggest that interplanetary shocks impacting away from the subsolar point caused the asymmetric current pattern. Additionally, even when PI currents form in both pre- and post-noon sectors, they can initiate and disappear at different timings. The PI currents did not immediately disappear but coexisted with the MI currents for the first few minutes of the MI. During a southward IMF, the MI currents formed equatorward of a preexisting DP-2, indicating that the MI currents are a separate structure from a preexisting DP-2. In contrast, the MI currents under a northward IMF were essentially an intensification of a preexisting DP-2. The magnetometer and imager combination has been shown to be a powerful means for tracing evolution of ionospheric currents, and we showed various types of ionospheric responses under different upstream conditions.

Distributed, cooperating knowledge-based systems

NASA Technical Reports Server (NTRS)

Truszkowski, Walt

1991-01-01

Some current research in the development and application of distributed, cooperating knowledge-based systems technology is addressed. The focus of the current research is the spacecraft ground operations environment. The underlying hypothesis is that, because of the increasing size, complexity, and cost of planned systems, conventional procedural approaches to the architecture of automated systems will give way to a more comprehensive knowledge-based approach. A hallmark of these future systems will be the integration of multiple knowledge-based agents which understand the operational goals of the system and cooperate with each other and the humans in the loop to attain the goals. The current work includes the development of a reference model for knowledge-base management, the development of a formal model of cooperating knowledge-based agents, the use of testbed for prototyping and evaluating various knowledge-based concepts, and beginning work on the establishment of an object-oriented model of an intelligent end-to-end (spacecraft to user) system. An introductory discussion of these activities is presented, the major concepts and principles being investigated are highlighted, and their potential use in other application domains is indicated.

Ionospheric and Birkeland current distributions inferred from the MAGSAT magnetometer data

NASA Technical Reports Server (NTRS)

Zanetti, L. J.; Potemra, T. A.; Baumjohann, W.

1983-01-01

Ionospheric and field-aligned sheet current density distributions are presently inferred by means of MAGSAT vector magnetometer data, together with an accurate magnetic field model. By comparing Hall current densities inferred from the MAGSAT data and those inferred from simultaneously recorded ground based data acquired by the Scandinavian magnetometer array, it is determined that the former have previously been underestimated due to high damping of magnetic variations with high spatial wave numbers between the ionosphere and the MAGSAT orbit. Among important results of this study is noted the fact that the Birkeland and electrojet current systems are colocated. The analyses have shown a tendency for triangular rather than constant electrojet current distributions as a function of latitude, consistent with the statistical, uniform regions 1 and 2 Birkeland current patterns.

Optimal joule heating of the subsurface

DOEpatents

Berryman, James G.; Daily, William D.

1994-01-01

A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Mapping the opacity of paint layers in paintings with coloured grounds using optical coherence tomography

NASA Astrophysics Data System (ADS)

Liu, Ping; Hall-Aquitania, Moorea; Hermens, Erma; Groves, Roger M.

2017-07-01

Optical diagnostics techniques are becoming important for technical art history (TAH) as well as for heritage conservation. In recent years, optical coherence tomography (OCT) has been increasingly used as a novel technique for the inspection of artwork, revealing the stratigraphy of paintings. It has also shown to be an effective tool for vanish layer inspection. OCT is a contactless and non-destructive technique for microstructural imaging of turbid media, originally developed for medical applications. However current OCT instruments have difficulty in paint layer inspection due to the opacity of most pigments. This paper explores the potential of OCT for the investigation of paintings with coloured grounds. Depth scans were processed to determine the light penetration depth at the optical wavelength based on a 1/e light attenuation calculation. The variation in paint opacity was mapped based on the microstructural images and 3D penetration depth profiles was calculated and related back to the construction of the artwork. By determining the light penetration depth over a range of wavelengths the 3D depth perception of a painting with coloured grounds can be characterized optically.

Hydrogeology and simulation of regional ground-water-level declines in Monroe County, Michigan

USGS Publications Warehouse

Reeves, Howard W.; Wright, Kirsten V.; Nicholas, J.R.

2004-01-01

Observed ground-water-level declines from 1991 to 2003 in northern Monroe County, Michigan, are consistent with increased ground-water demands in the region. In 1991, the estimated ground-water use in the county was 20 million gallons per day, and 80 percent of this total was from quarry dewatering. In 2001, the estimated ground-water use in the county was 30 million gallons per day, and 75 percent of this total was from quarry dewatering. Prior to approximately 1990, the ground-water demands were met by capturing natural discharge from the area and by inducing leakage through glacial deposits that cover the bedrock aquifer. Increased ground-water demand after 1990 led to declines in ground-water level as the system moves toward a new steady-state. Much of the available natural discharge from the bedrock aquifer had been captured by the 1991 conditions, and the response to additional withdrawals resulted in the observed widespread decline in water levels. The causes of the observed declines were explored through the use of a regional ground-water-flow model. The model area includes portions of Lenawee, Monroe, Washtenaw, and Wayne Counties in Michigan, and portions of Fulton, Henry, and Lucas Counties in Ohio. Factors, including lowered water-table elevations because of below average precipitation during the time period (1991 - 2001) and reduction in water supply to the bedrock aquifer because of land-use changes, were found to affect the regional system, but these factors did not explain the regional decline. Potential ground-water capture for the bedrock aquifer in Monroe County is limited by the low hydraulic conductivity of the overlying glacial deposits and shales and the presence of dense saline water within the bedrock as it dips into the Michigan Basin to the west and north of the county. Hydrogeologic features of the bedrock and the overlying glacial deposits were included in the model design. An important step of characterizing the bedrock aquifer was the determination of inputs and outputs of water—leakage from glacial deposits and flows across model boundaries. The imposed demands on the groundwater system create additional discharge from the bedrock aquifer, and this discharge is documented by records and estimates of water use including: residential and industrial use, irrigation, and quarry dewatering. Hydrologic characterization of Monroe County and surrounding areas was used to determine the model boundaries and inputs within the ground-water model. MODFLOW-2000 was the computer model used to simulate ground-water flow. Predevelopment, 1991, and 2001 conditions were simulated with the model. The predevelopment model did not include modern water use and was compared to information from early settlement of the county. The 1991 steady-state model included modern demands on the ground-water system and was based on a significant amount of data collected for this and previous studies. The predevelopment and 1991 simulations were used to calibrate the numerical model. The simulation of 2001 conditions was based on recent data and explored the potential ground-water levels if the current conditions persist. Model results indicate that the ground-water level will stabilize in the county near current levels if the demands imposed during 2001 are held constant.

46 CFR 183.372 - Equipment and conductor grounding.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Equipment and conductor grounding. 183.372 Section 183... conductor grounding. (a) All metallic enclosures and frames of electrical equipment must be permanently... equipment must be bonded together to a common ground by a normally non-current carrying conductor. Metallic...

46 CFR 120.372 - Equipment and conductor grounding.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Equipment and conductor grounding. 120.372 Section 120... INSTALLATION Power Sources and Distribution Systems § 120.372 Equipment and conductor grounding. (a) All... together to a common ground by a normally non-current carrying conductor. Metallic cases of instruments and...

46 CFR 183.372 - Equipment and conductor grounding.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Equipment and conductor grounding. 183.372 Section 183... conductor grounding. (a) All metallic enclosures and frames of electrical equipment must be permanently... equipment must be bonded together to a common ground by a normally non-current carrying conductor. Metallic...

46 CFR 120.372 - Equipment and conductor grounding.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Equipment and conductor grounding. 120.372 Section 120... INSTALLATION Power Sources and Distribution Systems § 120.372 Equipment and conductor grounding. (a) All... together to a common ground by a normally non-current carrying conductor. Metallic cases of instruments and...

Grounds Maintenance Cost Report.

ERIC Educational Resources Information Center

Joice, Donald K.

A grounds maintenance study was accomplished over the period of March 1965 through February 1966 to--(1) determine current grounds maintenance cost distribution; (2) provide basis for future grounds maintenance budgeting, and (3) provide basic data by which future landscape project designs can be developed to project or reduce maintenance costs.…

Monitoring and Modeling Crop Health and Water Use via in-situ, Airborne and Space-based Platforms

NASA Astrophysics Data System (ADS)

McCabe, M. F.

2014-12-01

The accurate retrieval of plant water use, health and function together with soil state and condition, represent key objectives in the management and monitoring of large-scale agricultural production. In regions of water shortage or stress, understanding the sustainable use of available water supplies is critical. Unfortunately, this need is all too often limited by a lack of reliable observations. Techniques that balance the demand for reliable ground-based data with the rapid retrieval of spatially distributed crop characteristics represent a needed line of research. Data from in-situ monitoring coupled with advances in satellite retrievals of key land surface variables, provide the information necessary to characterize many crop health and water use features, including evaporation, leaf-chlorophyll and other common vegetation indices. With developments in UAV and quadcopter solutions, the opportunity to bridge the spatio-temporal gap between satellite and ground based sensing now exists, along with the capacity for customized retrievals of crop information. While there remain challenges in the routine application of autonomous airborne systems, the state of current technology and sensor developments provide the capacity to explore the operational potential. While this presentation will focus on the multi-scale estimation of crop-water use and crop-health characteristics from satellite-based sensors, the retrieval of high resolution spatially distributed information from near-surface airborne and ground-based systems will also be examined.

Best Practices in Physics-Based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations

NASA Astrophysics Data System (ADS)

Dalguer, Luis A.; Fukushima, Yoshimitsu; Irikura, Kojiro; Wu, Changjiang

2017-09-01

Inspired by the first workshop on Best Practices in Physics-Based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations (BestPSHANI) conducted by the International Atomic Energy Agency (IAEA) on 18-20 November, 2015 in Vienna (http://www-pub.iaea.org/iaeameetings/50896/BestPSHANI), this PAGEOPH topical volume collects several extended articles from this workshop as well as several new contributions. A total of 17 papers have been selected on topics ranging from the seismological aspects of earthquake cycle simulations for source-scaling evaluation, seismic source characterization, source inversion and ground motion modeling (based on finite fault rupture using dynamic, kinematic, stochastic and empirical Green's functions approaches) to the engineering application of simulated ground motion for the analysis of seismic response of structures. These contributions include applications to real earthquakes and description of current practice to assess seismic hazard in terms of nuclear safety in low seismicity areas, as well as proposals for physics-based hazard assessment for critical structures near large earthquakes. Collectively, the papers of this volume highlight the usefulness of physics-based models to evaluate and understand the physical causes of observed and empirical data, as well as to predict ground motion beyond the range of recorded data. Relevant importance is given on the validation and verification of the models by comparing synthetic results with observed data and empirical models.

Thermal Conductivity Measurements of Helium 4 Near the Lambda-Transition Using a Magnetostrictive Low Gravity Simulator

NASA Technical Reports Server (NTRS)

Larson, Melora; Israelsson, Ulf E.

1995-01-01

There has been a recent increase in interest both experimentally and theoretically in the study of liquid helium very near the lambda-transition in the presence of a heat current. In traditional ground based experiments there are gravitationally induced pressure variations in any macroscopic helium sample that limit how closely the transition can be approached. We have taken advantage of the finite magnetic susceptibility of He 4 to build a magnetostrictive low gravity simulator. The simulator consists of a superconducting magnet with field profile shaped to counteract the force of gravity in a helium sample. When the magnet is operated with B x dB/dz = 21T(exp 2)/cm at the location of the cell, the gravitationally induced pressure variations will be canceled to within 1% over a volume of 0.5 cm in height and 0.5 cm in diameter. This technique for canceling the pressure variations in a long sample cell allows the lambda-transition to be studied much closer in reduced temperature and under a wider range of applied heat currents than is possible using other ground based techniques. Preliminary results using this low gravity simulator and the limitations of the magnetostrictive technique in comparison to doing space based experiments will be presented.

The WFIRST Microlensing Survey: Expectations and Unexpectations

NASA Astrophysics Data System (ADS)

Gaudi, B. Scott; Penny, Matthew

2016-01-01

The WFIRST microlensing survey will provide the definitive determination of the demographics of cool planets with semimajor axes > 1 AU and masses greater than that of the Earth, including free-floating planets. Together with the results from Kepler, TESS, and PLATO, WFIRST will complete the statistical census of planets in the Galaxy. These expectations are based on the most basic and conservative assumptions about the data quality, and assumes that the analysis methodologies will be similar to that used for current ground-based microlensing. Yet, in fact, the data quality will be dramatically better, and information content substantially richer, for the WFIRST microlensing survey as compared to current ground-based surveys. Thus WFIRST should allow for orders of magnitude improvement in both sensitivity and science yield. We will review some of these expected improvements and opportunities (the "known unknowns"), and provide a "to do list" of what tasks will need to be completed in order to take advantage of these opportunities. We will then speculate on the opportunities that we may not be aware of yet (the "unknown unknowns"), how we might go about determining what those opportunities are, and how we might figure out what we will need to do to take advantage of them.This work was partially supported by NASA grant NNX14AF63G.

30 CFR 75.902-4 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... SAFETY STANDARDS-UNDERGROUND COAL MINES Underground Low- and Medium-Voltage Alternating Current Circuits... from resistance grounded systems separate connections shall be used when practicable. ...

30 CFR 75.902-4 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... SAFETY STANDARDS-UNDERGROUND COAL MINES Underground Low- and Medium-Voltage Alternating Current Circuits... from resistance grounded systems separate connections shall be used when practicable. ...

30 CFR 75.902-4 - Attachment of ground conductors and ground check wires to equipment frames; use of separate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... SAFETY STANDARDS-UNDERGROUND COAL MINES Underground Low- and Medium-Voltage Alternating Current Circuits... from resistance grounded systems separate connections shall be used when practicable. ...

Precision envelope detector and linear rectifier circuitry

DOEpatents

Davis, Thomas J.

1980-01-01

Disclosed is a method and apparatus for the precise linear rectification and envelope detection of oscillatory signals. The signal is applied to a voltage-to-current converter which supplies current to a constant current sink. The connection between the converter and the sink is also applied through a diode and an output load resistor to a ground connection. The connection is also connected to ground through a second diode of opposite polarity from the diode in series with the load resistor. Very small amplitude voltage signals applied to the converter will cause a small change in the output current of the converter, and the difference between the output current and the constant current sink will be applied either directly to ground through the single diode, or across the output load resistor, dependent upon the polarity. Disclosed also is a full-wave rectifier utilizing constant current sinks and voltage-to-current converters. Additionally, disclosed is a combination of the voltage-to-current converters with differential integrated circuit preamplifiers to boost the initial signal amplitude, and with low pass filtering applied so as to obtain a video or signal envelope output.

Ground-based eye-safe networkable micro-pulse differential absorption and high spectral resolution lidar for water vapor and aerosol profiling in the lower troposphere

NASA Astrophysics Data System (ADS)

Repasky, K. S.; Spuler, S.; Hayman, M. M.; Bunn, C. E.

2017-12-01

Atmospheric water vapor is a greenhouse gas that is known to be a significant driver of weather and climate. Several National Research Council (NRC) reports have highlighted the need for improved water vapor measurements that can capture its spatial and temporal variability as a means to improve weather predictions. Researchers at Montana State University (MSU) and the National Center for Atmospheric Research (NCAR) have developed an eye-safe diode laser based micro-pulse differential absorption lidar (MP-DIAL) for water vapor profiling in the lower troposphere. The MP-DIAL is capable of long term unattended operation and is capable of monitoring water vapor in the lower troposphere in most weather conditions. Two MP-DIAL instruments are currently operational and have been deployed at the Front Range Air Pollution and Photochemistry Experiment (FRAPPE), the Plains elevated Convection at Night (PECAN) experiment, the Perdigão experiment, and the Land Atmosphere Feedback Experiment (LAFE). For each of these field experiments, the MP-DIAL was run unattended and provided near-continuous water vapor profiles, including periods of bright daytime clouds, from 300 m above the ground level to 4 km (or the cloud base) with 150 m vertical resolution and 5 minute temporal resolution. Three additional MP-DIAL instruments are currently under construction and will result in a network of five eye-safe MP-DIAL instruments for ground based weather and climate research experiments. Taking advantage of the broad spectral coverage and modularity or the diode based architecture, a high spectral resolution lidar (HSRL) measurement capabilities was added to the second MP-DIAL instrument. The HSRL capabilities will be operational during the deployment at the LAFE field experiment. The instrument architecture will be presented along with examples of data collected during recent field experiments.

A Lunar Optical-Ultraviolet-Infrared Synthesis Array (LOUISA)

NASA Technical Reports Server (NTRS)

Burns, Jack O. (Editor); Johnson, Stewart W. (Editor); Duric, Nebojsa (Editor)

1992-01-01

This document contains papers presented at a workshop held to consider 'optical ultraviolet infrared' interferometric observations from the moon. Part 1 is an introduction. Part 2 is a description of current and planned ground-based interferometers. Part 3 is a description of potential space-based interferometers. Part 4 addresses the potential for interferometry on the moon. Part 5 is the report of the workshop's working groups. Concluding remarks, summary, and conclusions are presented in Part 6.

Ultra-portable field transfer radiometer for vicarious calibration of earth imaging sensors

NASA Astrophysics Data System (ADS)

Thome, Kurtis; Wenny, Brian; Anderson, Nikolaus; McCorkel, Joel; Czapla-Myers, Jeffrey; Biggar, Stuart

2018-06-01

A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector- and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods.

Satellite propulsion spectral signature detection and analysis through Hall effect thruster plume and atmospheric modeling

NASA Astrophysics Data System (ADS)

Wheeler, Pamela; Cobb, Richard; Hartsfield, Carl; Prince, Benjamin

2016-09-01

Space Situational Awareness (SSA) is of utmost importance in today's congested and contested space environment. Satellites must perform orbital corrections for station keeping, devices like high efficiency electric propulsion systems such as a Hall effect thrusters (HETs) to accomplish this are on the rise. The health of this system is extremely important to ensure the satellite can maintain proper position and perform its intended mission. Electron temperature is a commonly used diagnostic to determine the efficiency of a hall thruster. Recent papers have coordinated near infrared (NIR) spectral measurements of emission lines in xenon and krypton to electron temperature measurements. Ground based observations of these spectral lines could allow the health of the thruster to be determined while the satellite is in operation. Another issue worth considering is the availability of SSA assets for ground-based observations. The current SSA architecture is limited and task saturated. If smaller telescopes, like those at universities, could successfully detect these signatures they could augment data collection for the SSA network. To facilitate this, precise atmospheric modeling must be used to pull out the signature. Within the atmosphere, the NIR has a higher transmission ratio and typical HET propellants are approximately 3x the intensity in the NIR versus the visible spectrum making it ideal for ground based observations. The proposed research will focus on developing a model to determine xenon and krypton signatures through the atmosphere and estimate the efficacy through ground-based observations. The model will take power modes, orbit geometries, and satellite altitudes into consideration and be correlated with lab and field observations.

Automated Planning of Science Products Based on Nadir Overflights and Alerts for Onboard and Ground Processing

NASA Technical Reports Server (NTRS)

Chien, Steve A.; McLaren, David A.; Rabideau, Gregg R.; Mandl, Daniel; Hengemihle, Jerry

2013-01-01

A set of automated planning algorithms is the current operations baseline approach for the Intelligent Payload Module (IPM) of the proposed Hyper spectral Infrared Imager (HyspIRI) mission. For this operations concept, there are only local (e.g. non-depletable) operations constraints, such as real-time downlink and onboard memory, and the forward sweeping algorithm is optimal for determining which science products should be generated onboard and on ground based on geographical overflights, science priorities, alerts, requests, and onboard and ground processing constraints. This automated planning approach was developed for the HyspIRI IPM concept. The HyspIRI IPM is proposed to use an X-band Direct Broadcast (DB) capability that would enable data to be delivered to ground stations virtually as it is acquired. However, the HyspIRI VSWIR and TIR instruments will produce approximately 1 Gbps data, while the DB capability is 15 Mbps for a approx. =60X oversubscription. In order to address this mismatch, this innovation determines which data to downlink based on both the type of surface the spacecraft is overflying, and the onboard processing of data to detect events. For example, when the spacecraft is overflying Polar Regions, it might downlink a snow/ice product. Additionally, the onboard software will search for thermal signatures indicative of a volcanic event or wild fire and downlink summary information (extent, spectra) when detected, thereby reducing data volume. The planning system described above automatically generated the IPM mission plan based on requested products, the overflight regions, and available resources.

Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

NASA Astrophysics Data System (ADS)

Zhu, Wei; Gould, Andrew

2016-06-01

Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.

An Analysis of Conjugate Ground-based and Space-based Measurements of Energetic Electrons during Substorms

NASA Astrophysics Data System (ADS)

Sivadas, N.; Semeter, J. L.

2015-12-01

Substorms within the Earth's magnetosphere release energy in the form of energetic charged particles and several kinds of waves within the plasma. Depending on their strength, satellite-based navigation and communication systems are adversely affected by the energetic charged particles. Like many other natural phenomena, substorms can have a severe economic impact on a technology-driven society such as ours. Though energization of charged particles is known to occur in the magnetosphere during substorms, the source of this population and its relation to traditional acceleration region dynamics, are not completely understood. Combining measurements of energetic charged particles within the plasmasheet and that of charged particles precipitated in to the ionosphere will provide a better understanding of the role of processes that accelerate these charged particles. In the current work, we present energetic electron flux measured indirectly using data from ground-based Incoherent Scatter Radar and that measured directly at the plasmasheet by the THEMIS spacecraft. Instances of low-altitude-precipitation observed from ground suggest electrons of energy greater than 300 keV, possibly arising from particle injection events during substorms at the magnetically conjugate locations in the plasmasheet. The differences and similarities in the measurements at the plasmasheet and the ionosphere indicate the role different processes play in influencing the journey of these energetic particles form the magnetosphere to the ionosphere. Our observations suggest that there is a lot more to be understood of the link between magnetotail dynamics and energetic electron precipitation during substorms. Understanding this may open up novel and potentially invaluable ways of diagnosing the magnetosphere from the ground.

The symbiosis of photometry and radial-velocity measurements

NASA Technical Reports Server (NTRS)

Cochran, William D.

1994-01-01

The FRESIP mission is optimized to detect the inner planets of a planetary system. According to the current paradigm of planet formation, these planets will probably be small Earth-sized objects. Ground-based radial-velocity programs now have the sensitivity to detect Jovian-mass planets in orbit around bright solar-type stars. We expect the more massive planets to form in the outer regions of a proto-stellar nebula. These two types of measurements will very nicely complement each other, as they have highest detection probability for very different types of planets. The combination of FRESIP photometry and ground-based spectra will provide independent confirmation of the existence of planetary systems in orbit around other stars. Such detection of both terrestrial and Jovian planets in orbit around the same star is essential to test our understanding of planet formation.

Guidance on the Stand Down, Mothball, and Reactivation of Ground Test Facilities

NASA Technical Reports Server (NTRS)

Volkman, Gregrey T.; Dunn, Steven C.

2013-01-01

The development of aerospace and aeronautics products typically requires three distinct types of testing resources across research, development, test, and evaluation: experimental ground testing, computational "testing" and development, and flight testing. Over the last twenty plus years, computational methods have replaced some physical experiments and this trend is continuing. The result is decreased utilization of ground test capabilities and, along with market forces, industry consolidation, and other factors, has resulted in the stand down and oftentimes closure of many ground test facilities. Ground test capabilities are (and very likely will continue to be for many years) required to verify computational results and to provide information for regimes where computational methods remain immature. Ground test capabilities are very costly to build and to maintain, so once constructed and operational it may be desirable to retain access to those capabilities even if not currently needed. One means of doing this while reducing ongoing sustainment costs is to stand down the facility into a "mothball" status - keeping it alive to bring it back when needed. Both NASA and the US Department of Defense have policies to accomplish the mothball of a facility, but with little detail. This paper offers a generic process to follow that can be tailored based on the needs of the owner and the applicable facility.

The effects of grounding (earthing) on inflammation, the immune response, wound healing, and prevention and treatment of chronic inflammatory and autoimmune diseases

PubMed Central

Oschman, James L; Chevalier, Gaétan; Brown, Richard

2015-01-01

Multi-disciplinary research has revealed that electrically conductive contact of the human body with the surface of the Earth (grounding or earthing) produces intriguing effects on physiology and health. Such effects relate to inflammation, immune responses, wound healing, and prevention and treatment of chronic inflammatory and autoimmune diseases. The purpose of this report is two-fold: to 1) inform researchers about what appears to be a new perspective to the study of inflammation, and 2) alert researchers that the length of time and degree (resistance to ground) of grounding of experimental animals is an important but usually overlooked factor that can influence outcomes of studies of inflammation, wound healing, and tumorigenesis. Specifically, grounding an organism produces measurable differences in the concentrations of white blood cells, cytokines, and other molecules involved in the inflammatory response. We present several hypotheses to explain observed effects, based on current research results and our understanding of the electronic aspects of cell and tissue physiology, cell biology, biophysics, and biochemistry. An experimental injury to muscles, known as delayed onset muscle soreness, has been used to monitor the immune response under grounded versus ungrounded conditions. Grounding reduces pain and alters the numbers of circulating neutrophils and lymphocytes, and also affects various circulating chemical factors related to inflammation. PMID:25848315

Space and ground-based GNSS activities at NOAA

NASA Astrophysics Data System (ADS)

Cucurull, L.

2016-12-01

With the launch of the FORMOSAT-3/COSMIC satellites in April 2006, the availability of Global Navigation Satellite Systems (GNSS) Radio Occultation (RO) observations for operational Numerical Weather Prediction (NWP) applications began. GNSS RO profiles started being assimilated operationally in the major worldwide weather centers soon after. NOAA started assimilating RO data operationally in early 2007. After COSMIC, other missions carrying GNSS RO receivers became available for operational uses. The incorporation of RO observations into the operational assimilation systems was shown to improve global model forecast skill. Since its launch in 2006, the COSMIC constellation has been the mainstay of the global RO system. However, COSMIC is already past the end of its formal lifetime, and only three satellites are still operating. This has motivated NOAA to invest on the COSMIC-2 mission, a 12-satellite constellation, that will replace COSMIC. The first launch, in equatorial orbit, is planned for March 2017. In addition to the space-based component of the GNSS technique, NOAA is assimilating ground-based products into its operational regional models. Although most stations over CONUS provide estimates of Precipitable Water (PW), this is not the case outside the U.S., where the required auxiliary meteorological information is generally not available. Thus, in order to evaluate the impact of ground-based GNSS products on a global weather model, the assimilation of less derived products, such as zenith total delays, rather than PW, is necessary. The talk will include an update on current activities and future plans for the utilization of space and ground-based GNSS products at NOAA. In addition, an update on the COSMIC-2 mission will be discussed.

MAVEN Information Security Governance, Risk Management, and Compliance (GRC): Lessons Learned

NASA Technical Reports Server (NTRS)

Takamura, Eduardo; Gomez-Rosa, Carlos A.; Mangum, Kevin; Wasiak, Fran

2014-01-01

As the first interplanetary mission managed by the NASA Goddard Space Flight Center, the Mars Atmosphere and Volatile EvolutioN (MAVEN) had three IT security goals for its ground system: COMPLIANCE, (IT) RISK REDUCTION, and COST REDUCTION. In a multiorganizational environment in which government, industry and academia work together in support of the ground system and mission operations, information security governance, risk management, and compliance (GRC) becomes a challenge as each component of the ground system has and follows its own set of IT security requirements. These requirements are not necessarily the same or even similar to each other's, making the auditing of the ground system security a challenging feat. A combination of standards-based information security management based on the National Institute of Standards and Technology (NIST) Risk Management Framework (RMF), due diligence by the Mission's leadership, and effective collaboration among all elements of the ground system enabled MAVEN to successfully meet NASA's requirements for IT security, and therefore meet Federal Information Security Management Act (FISMA) mandate on the Agency. Throughout the implementation of GRC on MAVEN during the early stages of the mission development, the Project faced many challenges some of which have been identified in this paper. The purpose of this paper is to document these challenges, and provide a brief analysis of the lessons MAVEN learned. The historical information documented herein, derived from an internal pre-launch lessons learned analysis, can be used by current and future missions and organizations implementing and auditing GRC.

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

Blom, Philip Stephen; Marcillo, Omar Eduardo; Euler, Garrett Gene

InfraPy is a Python-based analysis toolkit being development at LANL. The algorithms are intended for ground-based nuclear detonation detection applications to detect, locate, and characterize explosive sources using infrasonic observations. The implementation is usable as a stand-alone Python library or as a command line driven tool operating directly on a database. With multiple scientists working on the project, we've begun using a LANL git repository for collaborative development and version control. Current and planned work on InfraPy focuses on the development of new algorithms and propagation models. Collaboration with Southern Methodist University (SMU) has helped identify bugs and limitations ofmore » the algorithms. The current focus of usage development is focused on library imports and CLI.« less

High Voltage Discharge Profile on Soil Breakdown Using Impulse Discharge

NASA Astrophysics Data System (ADS)

Fajingbesi, F. E.; Midi, N. S.; Elsheikh, E. M. A.; Yusoff, S. H.

2017-06-01

Grounding terminals are mandatory in electrical appliance design as they provide safety route during overvoltage faults. The soil (earth) been the universal ground is assumed to be at zero electric potential. However, due to properties like moisture, pH and available nutrients; the electric potential may fluctuate between positive and negative values that could be harmful for internally connected circuits on the grounding terminal. Fluctuations in soil properties may also lead to current crowding effect similar to those seen at the emitters of semiconductor transistors. In this work, soil samples are subjected to high impulse voltage discharge and the breakdown characteristics was profiled. The results from profiling discharge characteristics of soil in this work will contribute to the optimization of grounding protection system design in terms of electrode placement. This would also contribute to avoiding grounding electrode current crowding, ground potential rise fault and electromagnetic coupling faults.