WorldWideScience

Sample records for surface stations comparisons

  1. A comparison of information on clouds and phenomena accompanying Cb obtained from surface and radar net stations

    Science.gov (United States)

    Gashina, S. B.; Matveyeva, L. I.; Razumovskiy, A. A.

    1975-01-01

    Methods and criteria are proposed for the comparison of surface and radar data on clouds and phenomena accompanying Cb. It is shown that the effectiveness of the radar information on thunderstorms from a net over the territory of the BSSR is approximately 3 times greater than that of visual observations obtained from the station net.

  2. Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

    Science.gov (United States)

    Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

    2014-01-01

    The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

  3. Comparison of Satellite-Derived Land Surface Temperature and Air Temperature from Meteorological Stations on the Pan-Arctic Scale

    Directory of Open Access Journals (Sweden)

    Christiane Schmullius

    2013-05-01

    Full Text Available Satellite-based temperature measurements are an important indicator for global climate change studies over large areas. Records from Moderate Resolution Imaging Spectroradiometer (MODIS, Advanced Very High Resolution Radiometer (AVHRR and (Advanced Along Track Scanning Radiometer ((AATSR are providing long-term time series information. Assessing the quality of remote sensing-based temperature measurements provides feedback to the climate modeling community and other users by identifying agreements and discrepancies when compared to temperature records from meteorological stations. This paper presents a comparison of state-of-the-art remote sensing-based land surface temperature data with air temperature measurements from meteorological stations on a pan-arctic scale (north of 60° latitude. Within this study, we compared land surface temperature products from (AATSR, MODIS and AVHRR with an in situ air temperature (Tair database provided by the National Climate Data Center (NCDC. Despite analyzing the whole acquisition time period of each land surface temperature product, we focused on the inter-annual variability comparing land surface temperature (LST and air temperature for the overlapping time period of the remote sensing data (2000–2005. In addition, land cover information was included in the evaluation approach by using GLC2000. MODIS has been identified as having the highest agreement in comparison to air temperature records. The time series of (AATSR is highly variable, whereas inconsistencies in land surface temperature data from AVHRR have been found.

  4. Near–surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    Directory of Open Access Journals (Sweden)

    C. L. Pérez Díaz

    2015-08-01

    Full Text Available Land Surface Temperature (LST is a key variable (commonly studied to understand the hydrological cycle that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air and snow skin temperature (T-skin helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

  5. Near-surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    Science.gov (United States)

    Pérez Díaz, C. L.; Lakhankar, T.; Romanov, P.; Muñoz, J.; Khanbilvardi, R.; Yu, Y.

    2015-08-01

    Land Surface Temperature (LST) is a key variable (commonly studied to understand the hydrological cycle) that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air) and snow skin temperature (T-skin) helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS) LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE) for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

  6. Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

    Directory of Open Access Journals (Sweden)

    W. Thiery

    2012-04-01

    Full Text Available In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance. Comparison to three other AWSs in Dronning Maud Land shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23 % of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (18 mm w.e. yr–1 compared to 42 mm w.e. yr–1 at Svea Cross and 52 mm w.e. yr–1 at Wasa/Aboa. This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and therefore on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. These wind speed classes turn out to contribute most to the total snowdrift sublimation mass flux, given their ability to lift a high number of particles while still allowing for considerable undersaturation.

  7. Recent surface mass balance from Syowa Station to Dome F, East Antarctica: comparison of field observations, atmospheric reanalyses, and a regional atmospheric climate model

    Science.gov (United States)

    Wang, Yetang; Hou, Shugui; Sun, Weijun; Lenaerts, Jan T. M.; van den Broeke, Michiel R.; van Wessem, J. M.

    2015-11-01

    Stake measurements at 2 km intervals are used to determine the spatial and temporal surface mass balance (SMB) in recent decades along the Japanese Antarctic Research Expedition traverse route from Syowa Station to Dome F. To determine SMB variability at regional scales, this traverse route is divided into four regions, i.e., coastal, lower katabatic, upper katabatic and inland plateau. We also perform a regional evaluation of large scale SMB simulated by the regional atmospheric climate model versions 2.1 and 2.3 (RACMO2.1 and RACMO2.3), and the four more recent global reanalyses. Large-scale spatial variability in the multi-year averaged SMB reveals robust relationships with continentality and surface elevation. In the katabatic regions, SMB variability is also highly associated with surface slope, which in turn is affected by bedrock topography. Stake observation records show large inter-annual variability in SMB, but did not indicate any significant trends over both the last 40 years for the coastal and lower katabatic regions, and the last 20 years record for the upper katabatic and inland plateau regions. The four reanalyses and the regional climate model reproduce the macro-scale spatial pattern well for the multi-year averaged SMB, but fail to capture the mesoscale SMB increase at the distance interval ~300 to ~400 km from Syowa station. Thanks to the updated scheme in the cloud microphysics, RACMO2.3 shows the best spatial agreement with stake measurements over the inland plateau region. ERA-interim, JRA-55 and MERRA exhibit high agreement with the inter-annual variability of observed SMB in the coastal, upper katabatic and inland plateau regions, and moderate agreement in the lower katabatic region, while NCEP2 and RACMO2.1 inter-annual variability shows no significant correlation with the observations for the inland plateau region.

  8. Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

    Directory of Open Access Journals (Sweden)

    W. Thiery

    2012-08-01

    Full Text Available In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance during 2009 and 2010. Comparison to three other AWSs in Dronning Maud Land with 11 to 13 yr of observations shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23% of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (17 mm w.e. yr−1 compared to 42 mm w.e. yr−1 at Svea Cross and 52 mm w.e. yr−1 at Wasa/Aboa. This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and, therefore, on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. This wind speed class turns out to contribute most to the total snowdrift sublimation mass flux, given its ability to lift a high number of particles while still allowing for considerable undersaturation.

  9. Surface science station of the infrared beamline at SPring-8

    CERN Document Server

    Sakurai, M; Kimura, H; Nishida, S; Nanba, T

    2001-01-01

    An experimental station for surface science has been constructed at the infrared beamline (BL43IR) of SPring-8, Japan. The station utilizes synchrotron radiation in the energy range of 100-20000 cm sup - sup 1 to perform infrared reflection absorption spectroscopy (IRAS) of surfaces. It consists of an experimental section, a preparation chamber, gas handling equipment and a pair of focusing optics. In situ observation of vibrational spectra is possible using both IRAS and high-resolution electron energy loss spectroscopy.

  10. EUROMET SUPPLEMENTARY COMPARISON - SURFACE TEXTURE

    DEFF Research Database (Denmark)

    Koenders, L.; Andreasen, Jan Lasson; De Chiffre, Leonardo

    At the length meeting in Prague in Oct. 1999 a new comparison was suggested on surface texture. The last comparison on this field was finished in 1989. In the meantime the instrumentation, the standards and the written standards have been improved including some software filters. The pilot...... laboratories for this supplementary comparison on surface texture are the Centre for Geometrical Metrology at the Technical University of Denmark and the Micro- and Nanotopography laboratory at the Physikalisch-Technische Bundesanstalt, Germany....

  11. Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

    NARCIS (Netherlands)

    Thiery, W.; Gorodetskaya, I.V.; Bintanja, R.; van Lipzig, N.P.M.; van den Broeke, M.R.; Reijmer, C.H.; Kuipers Munneke, P.

    2012-01-01

    In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian r

  12. Milliwatt radioisotope power supply for the PASCAL Mars surface stations

    Science.gov (United States)

    Allen, Daniel T.; Murbach, Marcus S.

    2001-02-01

    A milliwatt power supply is being developed based on the 1 watt Light-Weight Radioisotope Heater Unit (RHU), which has already been used to provide heating alone on numerous spacecraft. In the past year the power supply has been integrated into the design of the proposed PASCAL Mars Network Mission, which is intended to place 24 surface climate monitoring stations on Mars. The PASCAL Mars mission calls for the individual surface stations to be transported together in one spacecraft on a trajectory direct from launch to orbit around Mars. From orbit around Mars each surface station will be deployed on a SCRAMP (slotted compression ramp) probe and, after aerodynamic and parachute deceleration, land at a preselected location on the planet. During descent sounding data and still images will be accumulated, and, once on the surface, the station will take measurements of pressure, temperature and overhead atmospheric optical depth for a period of 10 Mars years (18.8 Earth years). Power for periodic data acquisition and transmission to orbital then to Earth relay will come from a bank of ultracapacitors which will be continuously recharged by the radioisotope power supply. This electronic system has been designed and a breadboard built. In the ultimate design the electronics will be arrayed on the exterior surface of the radioisotope power supply in order to take advantage of the reject heat. This assembly in turn is packaged within the SCRAMP, and that assembly comprises the surface station. An electrically heated but otherwise prototypical power supply was operated in combination with the surface station breadboard system, which included the ultracapacitors. Other issues addressed in this work have been the capability of the generator to withstand the mechanical shock of the landing on Mars and the effectiveness of the generator's multi-foil vacuum thermal insulation. .

  13. Index of surface-water stations in Texas, January 1988

    Science.gov (United States)

    Rawson, Jack; Carrillo, E.R.; Buckner, H.D.

    1988-01-01

    As of January 1, 1988, the surface-water data-collection network in Texas included 368 continuous streamflow, 12 continuous or daily reservoir-content, 38 gage height, 15 crest-stage partia 1-record, 4 periodic discharge through range, 32 floodhydrocjraph partial-record, 9 flood-profile partial-record, 36 low-flow partial-record 45 daily chemical-quality, 19 continuous-recording water-quality, 83 periodic biological, 19 lake surveys, 160 periodic organic and (or) nutrient, 3 periodic insecticide, 33 periodic pesticide, 20 automatic sampler, 137 periodic minor elements, 125 periodic chemical-quality, 74 periodic physica1-organic, 24 continuous-recording three- or four-parameter water-quality, 34 periodic sediment, 21 continuous-recording temperature, and 30 national stream-quality accounting network stations. Plate 1 shows the location of surface-water streamflow or reservoir-content and chemicalquality or sediment stations in Texas. Plate 2 shows the location of partial-record surface-water stations.

  14. Index of surface-water stations in Texas, January 1987

    Science.gov (United States)

    Rawson, Jack; Carrillo, E.R.; Buckner, H.D.

    1987-01-01

    As of January 1, 1987, the surface-water data-collection network in Texas included 376 continuous streamflow, 76 continuous or daily reservoir-content, 34 gage height, 16 crest-stage partial-record, 8 periodic discharge through range, 33 floodhydrograph partial-record, 9 flood-profile partial-record, 36 low-flow partial-record, 46 daily chemical-quality, 19 continuous-recording water-quality, 84 periodic biological, 17 lake surveys, 162 periodic organic and (or) nutrient, 3 periodic insecticide, 42 periodic pesticide, 19 automatic sampler, 141 periodic minor elements, 130 periodic chemical-quality, 78 periodic physical-organic, 22 continuous-recording three- or four-parameter water-quality, 34 periodic sediment, 22 continuous-recording temperature, and 30 national stream-quality accounting network stations. Plate 1 shows the location of surface-water streamflow or reservoir-content and chemical-quality or sediment'stations in Texas. Plate 2 shows the location of partial-record surfacewater stations.

  15. Station-based Surface Data Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Q. [DOE ARM Climate Research Facility, Washington, DC (United States); Xie, S. [DOE ARM Climate Research Facility, Washington, DC (United States)

    2015-07-01

    This report describes the Atmospheric Radiation Measurement (ARM) Best Estimate (ARMBE) station-based surface data (ARMBESTNS) value-added product. It is a twin data product of the ARMBE 2-Dimensional gridded (ARMBE2DGRID) data set. Unlike the ARMBE2DGRID data set, ARMBESTNS data are reported at the original site locations and show the original information (except for the interpolation over time). Therefore, the users have the flexibility to process the data with the approach more suitable for their applications. This document provides information about the input data, quality control (QC) method, and output format of this data set. As much of the information is identical to that of the ARMBE2DGRID data, this document will emphasize more on the different aspects of these two data sets.

  16. Surface ozone observation at Syowa Station, Antarctica from February 1982 to January 1983

    OpenAIRE

    Shigeru, Chubachi

    1985-01-01

    This paper presents the result of surface ozone measurement at Syowa Station from February 1982 to January 1983 with a Dasibi ozone meter. In order to improve the reliability, the instrument was calibrated in Japan before and after the observation. The surface ozone mixing ratio at Syowa Station shows the annual change with a winter maximum and a summer minimum, being quite similar to that at Amundsen-Scott (South Pole) Station.

  17. Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

    Science.gov (United States)

    Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

    2016-01-01

    This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

  18. Effect of Surface Geology on Ground Motions: The Case of Station TAP056 - Chutzuhu Site

    Directory of Open Access Journals (Sweden)

    Kuo-Liang Wen

    2008-01-01

    Full Text Available In the Tatun mountain area of northern Taiwan are two strong motion stations approximately 2.5 km apart, TAP056 and TAP066 of the TSMIP network. The accelerometer at station TAP056 is often triggered by earthquakes, but that at TAP066 station is not. Comparisons of vertical and horizontal peak ground accelerations reveal PGA in the vertical, east-west, and north-south components at TAP056 station to be 3.89, 7.57, and 5.45 times those at station TAP066, respectively. The PGA ratio does not seem to be related to earthquake source or path. Fourier spectra of earthquake records at station TAP056 always have approximately the same dominant frequency; however, those at station TAP066 are different due to different sources and paths of different events. This shows that spectra at TAP056 station are mainly controlled by local site effects. The spectral ratios of TAP056/TAP066 show the S-wave is amplified at around 8 ~ 10 Hz. The horizontal/vertical spectral ratios of station TAP056 also show a dominant frequency at about 6 and 8 ~ 10 Hz. After dense microtremor surveying and the addition of one accelerometer just 20 meters away from the original observation station, we can confirm that the top soft soil layer upon which the observation station is constructed generates the local site response at station TAP056.

  19. Surface energy balance, melt and sublimation at Neumayer Station, East Antarctica

    NARCIS (Netherlands)

    van den Broeke, M.R.; König-Langlo, G.; Picard, G.; Kuipers Munneke, P.; Lenaerts, J.T.M.

    2009-01-01

    A surface energy balance model is forced by 13 years of high-quality hourly observations from the Antarctic coastal station Neumayer. The model accurately reproduces observed surface temperatures. Surface sublimation is significant in summer, when absorbed solar radiation heats the surface. Includin

  20. Changes in satellite-derived impervious surface area at US historical climatology network stations

    Science.gov (United States)

    Gallo, Kevin; Xian, George

    2016-10-01

    The difference between 30 m gridded impervious surface area (ISA) between 2001 and 2011 was evaluated within 100 and 1000 m radii of the locations of climate stations that comprise the US Historical Climatology Network. The amount of area associated with observed increases in ISA above specific thresholds was documented for the climate stations. Over 32% of the USHCN stations exhibited an increase in ISA of ⩾20% between 2001 and 2011 for at least 1% of the grid cells within a 100 m radius of the station. However, as the required area associated with ISA change was increased from ⩾1% to ⩾10%, the number of stations that were observed with a ⩾20% increase in ISA between 2001 and 2011 decreased to 113 (9% of stations). When the 1000 m radius associated with each station was examined, over 52% (over 600) of the stations exhibited an increase in ISA of ⩾20% within at least 1% of the grid cells within that radius. However, as the required area associated with ISA change was increased to ⩾10% the number of stations that were observed with a ⩾20% increase in ISA between 2001 and 2011 decreased to 35 (less than 3% of the stations). The gridded ISA data provides an opportunity to characterize the environment around climate stations with a consistently measured indicator of a surface feature. Periodic evaluations of changes in the ISA near the USHCN and other networks of stations are recommended to assure the local environment around the stations has not significantly changed such that observations at the stations may be impacted.

  1. Austrian dose measurements onboard space station MIR and the International Space Station--overview and comparison.

    Science.gov (United States)

    Berger, T; Hajek, M; Summerer, L; Vana, N; Akatov, Y; Shurshakov, V; Arkhangelsky, V

    2004-01-01

    The Atominstitute of the Austrian Universities has conducted various space research missions in the last 12 years in cooperation with the Institute for Biomedical Problems in Moscow. They dealt with the exact determination of the radiation hazards for cosmonauts and the development of precise measurement devices. Special emphasis will be laid on the last experiment on space station MIR the goal of which was the determination of the depth distribution of absorbed dose and dose equivalent in a water filled Phantom. The first results from dose measurements onboard the International Space Station (ISS) will also be discussed. The spherical Phantom with a diameter of 35 cm was developed at the Institute for Biomedical Problems and had 4 channels where dosimeters can be exposed in different depths. The exposure period covered the timeframe from May 1997 to February 1999. Thermoluminescent dosimeters (TLDs) were exposed inside the Phantom, either parallel or perpendicular to the hull of the spacecraft. For the evaluation of the linear energy transfer (LET), the high temperature ratio (HTR) method was applied. Based on this method a mean quality factor and, subsequently, the dose equivalent is calculated according to the Q(LET infinity) relationship proposed in ICRP 26. An increased contribution of neutrons could be detected inside the Phantom. However the total dose equivalent did not increase over the depth of the Phantom. As the first Austrian measurements on the ISS dosimeter packages were exposed for 248 days, starting in February 2001 at six different locations onboard the ISS. The Austrian dosimeter sets for this first exposure on the ISS contained five different kinds of passive thermoluminescent dosimeters. First results showed a position dependent absorbed dose rate at the ISS.

  2. Comparison Between Radar and Automatic Weather Station Refractivity Variability

    Science.gov (United States)

    Hallali, Ruben; Dalaudier, Francis; Parent du Chatelet, Jacques

    2016-08-01

    Weather radars measure changes in the refractive index of air in the atmospheric boundary layer. The technique uses the phase of signals from ground targets located around the radar to provide information on atmospheric refractivity related to meteorological quantities such as temperature, pressure and humidity. The approach has been successfully implemented during several field campaigns using operational S-band radars in Canada, UK, USA and France. In order to better characterize the origins of errors, a recent study has simulated temporal variations of refractivity based on Automatic Weather Station (AWS) measurements. This reveals a stronger variability of the refractivity during the summer and in the afternoon when the refractivity is the most sensitive to humidity, probably because of turbulence close to the ground. This raises the possibility of retrieving information on the turbulent state of the atmosphere from the variability in radar refractivity. An analysis based on a 1-year dataset from the operational C-band radar at Trappes (near Paris, France) and AWS refractivity variability measurements was used to measure those temporal and spatial variabilities. Particularly during summer, a negative bias increasing with range is observed between radar and AWS estimations, and is well explained by a model based on Taylor's hypotheses. The results demonstrate the possibility of establishing, depending on season, a quantitative and qualitative link between radar and AWS refractivity variability that reflects low-level coherent turbulent structures.

  3. Surface Wave Tomography of South China Sea from Ambient Seismic Noise and Two-station Measurements

    Science.gov (United States)

    Liang, W.-T.; Gung, Y.-C.

    2012-04-01

    We have taken the cross-correlation of seismic ambient noise technique as well as the two-station method to analyze the velocity structure in the South China Sea region. The dataset used in this study includes broadband waveforms recorded at the Taiwan BATS (Broadband Array in Taiwan for Seismology), Japan OHP (Ocean Hemisphere Project), Malaysia and Vietnam seismic networks. We remove the instrument response from daily data and filter the waveform with various frequency bands according to the length of each station-pair. Then we apply the commonly used 1-bit normalization to minimize the effect of earthquakes, instrumental irregularities, and non-stationary noise sources near to the stations. With the derived daily cross correlation function (CCF), we are able to examine the timing quality for each station-pair. We then obtain the surface Rayleigh wave dispersion curves from the stacked CCF for each station-pair. To cover the longer period band in the dispersion curves, we adopt the two-station method to compute both the group and phase velocities of surface waves. A new surface wave tomography based on ambient seismic noise study and traditional two-station technique has been achieved in this study. Raypaths that travel through the Central basin present higher velocity, which is in agreement with the idea of thin crust. On the other hand, the slower velocity between Taiwan and Northern Luzon, Philippine is mainly due to a thick accretionary prism above the Manila trench.

  4. New PBO GPS Station Construction: Eastern Region Network Enhancements and Multiple-Monument Stability Comparisons

    Science.gov (United States)

    Dittmann, S. T.; Austin, K. E.; Berglund, H. T.; Blume, F.; Feaux, K.; Mann, D.; Mattioli, G. S.; Walls, C. P.

    2013-12-01

    The Plate Boundary Observatory (PBO) network consists of 1100 continuously operating, permanent GPS stations throughout the United States. The majority of this network was constructed using NSF-MREFC funding as part of the EarthScope Project during FY2003-FY2008. Since FY2009, UNAVCO has operated and maintained PBO through a Cooperative Agreement (CA) with NSF. Construction of new, permanent GPS monuments in the PBO network was the result of two change orders to the original PBO O&M CA. Change Order 33 (CO33) allocated funds to construct additional GPS stations at six locations in the Eastern Region of PBO. Three of these locations were designed to replace poorly performing existing GPS monuments in Georgia, Texas and New York. The remaining three new locations were selected to fill in gaps in network coverage in Pennsylvania, Wisconsin and North Dakota. Construction of all six new sites was completed in September 2013. Important scientific goals for CO33 include improvement of the stable North American reference frame, measurement of the vertical signal associated with the Glacial Isostatic Adjustment, and improved constraints on surface deformation and possible earthquakes, which occur in the low-strain tectonic setting of the eastern North American Plate. Change Order 35 (CO35) allocated funds to construct two additional geodetic monuments at five existing PBO stations in order to test and compare the long-term stability of various monument designs under near-identical geologic conditions. Sites were chosen to yield a variety of geographic, hydrologic and geologic conditions, including both fine-grained alluvium and crystalline bedrock. At each location, three different monuments (deep drill braced, short drill braced/driven-braced, mast/pillar) were built with 10 meter spacing, with shared power systems and data telemetry infrastructure. Construction of these multi-monument test locations began in October 2012 and finished in September 2013. See G010- Berglund

  5. Diurnal variability of surface fluxes at an oceanic station in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, Y.V.B.; Rao, D.P.

    Diurnal variability of the surface fluxes and ocean heat content was studied using the time-series data on marine surface meteorological parameters and upper ocean temperature collected at an oceanic station in the Bay of Bengal during 1st to 8th...

  6. A stratification model of surface snow at Dome Fuji Station, Antarctica

    OpenAIRE

    2002-01-01

    A stratification model of surface snow on the ice sheet, which includes snow density evolution, is proposed. Using the temperature profile in the surface snow layer obtained at Dome Fuji Station, Antarctica, snow density evolution under various accumulation conditions was simulated. It is demonstrated that water vapor diffusion is very important for the snow density evolution, and temperature and accumulation at the snow surface are the most important factors that determine the future snow de...

  7. A stratification model of surface snow at Dome Fuji Station, Antarctica

    OpenAIRE

    2002-01-01

    A stratification model of surface snow on the ice sheet, which includes snow density evolution, is proposed. Using the temperature profile in the surface snow layer obtained at Dome Fuji Station, Antarctica, snow density evolution under various accumulation conditions was simulated.It is demonstrated that water vapor diffusion is very important for the snow density evolution, and temperature and accumulation at the snow surface are the most important factors that determine the future snow den...

  8. On measuring surface wave phase velocity from station–station cross-correlation of ambient signal

    DEFF Research Database (Denmark)

    Boschi, Lapo; Weemstra, Cornelis; Verbeke, Julie

    2012-01-01

    We apply two different algorithms to measure surface wave phase velocity, as a function of frequency, from seismic ambient noise recorded at pairs of stations from a large European network. The two methods are based on consistent theoretical formulations, but differ in the implementation: one met...

  9. Energy balance of a glacier surface: analysis of Automatic Weather Station data from the Morteratschgletscher, Switzerland

    NARCIS (Netherlands)

    Oerlemans, J.; Klok, E.J.

    2002-01-01

    We describe and analyze a complete 1-yr data set from an automatic weather station (AWS) located on the snout of the Morteratschgletscher, Switzerland. The AWS stands freely on the glacier surface and measures pressure, windspeed, wind direction, air temperature and humidity, incoming and reflected

  10. Baseline Surface Radiation Network (BSRN) quality control of solar radiation data on the Gangneung-Wonju National University radiation station

    Science.gov (United States)

    Zo, Il-Sung; Jee, Joon-Bum; Kim, Bu-Yo; Lee, Kyu-Tae

    2017-02-01

    Gangneung-Wonju National University (GWNU) radiation station has been collecting data on global, direct, and diffuse solar radiation since 2011. We conducted a quality control (QC) assessment of GWNU data collected between 2012 and 2014, using procedures outlined by the Baseline Surface Radiation Network (BSRN). The QC process involved the comparison of observations, the correction of observational equipment, the examination of physically possible limits, and the comparative testing of observations and model calculations. Furthermore, we performed a shading check of the observational environment around the GWNU solar station. For each solar radiation element (observed every minute), we performed a QC check and investigated any flagged problems. 98.31% of the data were classified as good quality, while the remaining 1.69% were flagged as bad quality based on the shading check and comparison tests. We then compared the good-quality data to the global solar radiation data observed at the Gangwon Regional Office of Meteorology (GROM). After performing this comparison, the determination coefficient (R2; 0.98) and standard deviation (SD; 0.92 MJ m-2) increased compared to those computed before the QC check (0.97 and 1.09 MJ m-2). Even considering the geographical differences and weather effects between the two stations, these results are statistically significant. However, we also confirmed that the quality of the GROM data deteriorated in relation to weather conditions because of poor maintenance. Hence, we conclude that good-quality observational data rely on the maintenance of both observational equipment and the surrounding environment under optimal conditions.

  11. Comparison of microwave satellite humidity data and radiosonde profiles: a survey of European stations

    Directory of Open Access Journals (Sweden)

    V. O. John

    2005-03-01

    Full Text Available A method to compare upper tropospheric humidity (UTH from satellite and radiosonde data has been applied to the European radiosonde stations. The method uses microwave data as a benchmark for monitoring the performance of the stations. The present study utilizes three years (2002–2003 of data from channel 18 (183.31±1.00 GHz of the Advanced Microwave Sounding Unit-B (AMSU-B aboard the satellites NOAA-15 and NOAA-16. The comparison is done in the radiance space, the radiosonde data were transformed to the channel radiances using a radiative transfer model. The comparison results confirm that there is a dry bias in the UTH measured by the radiosondes. This bias is highly variable among the stations and the years. This variability is attributed mainly to the differences in the radiosonde humidity measurements. The results also hint at a systematic difference between the two satellites, the channel 18 brightness temperature of NOAA-15 is on average 1.0 K higher than that of NOAA-16. The difference of 1 K corresponds to approximately 7% relative error in UTH which is significant for climatological applications.

  12. Study on Removal Distance of a Crushing Station in Buzhaoba Surface Mine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A semi-continuous technology combines the merits of discontinuous and continuous technologies. Compared with the discontinuous technology, the semi-continuous technology can be used to decrease haulage costs in mines because of the use of a belt conveyor instead of trucks. The method may improve efficiency by using shovels instead of BWE. This paper discusses the removal distance of a crushing station based on the Buzhaoba surface mine.

  13. Surface flow observations from a gauge-cam station on the Tiber river

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Petroselli, Andrea; Grimaldi, Salvatore

    2016-04-01

    Understanding the kinematic organization of natural water bodies is central to hydrology and environmental engineering practice. Reliable and continuous flow observations are essential to comprehend flood generation and propagation mechanisms, erosion dynamics, sediment transport, and drainage network evolution. In engineering practice, flood warning systems largely rely on real-time discharge measurements, and flow velocity monitoring is important for the design and management of hydraulic structures, such as reservoirs and hydropower plants. Traditionally, gauging stations have been equipped with water level meters, and stage-discharge relationships (rating curves) have been established through few direct discharge measurements. Only in rare instances, monitoring stations have integrated radar technology for local measurement of surface flow velocity. Establishing accurate rating curves depends on the availability of a comprehensive range of discharge values, including measurements recorded during extreme events. However, discharge values during high-flow events are often difficult or even impossible to obtain, thereby hampering the reliability of discharge predictions. Fully remote observations have been enabled in the past ten years through optics-based velocimetry techniques. Such methodologies enable the estimation of the surface flow velocity field over extended regions from the motion of naturally occurring debris or floaters dragged by the current. Resting on the potential demonstrated by such approaches, here, we present a novel permanent gauge-cam station for the observation of the flow velocity field in the Tiber river. This new station captures one-minute videos every 10 minutes over an area of up to 20.6 × 15.5m2. In a feasibility study, we demonstrate that experimental images analyzed via particle tracking velocimetry and particle image velocimetry can be used to obtain accurate surface flow velocity estimations in close agreement with radar records

  14. Global solar radiation: comparison of satellite-based climatology with station records

    Science.gov (United States)

    Skalak, Petr; Zahradnicek, Pavel; Stepanek, Petr; Farda, Ales

    2016-04-01

    We analyze surface incoming shortwave radiation (SIS) from the SARAH dataset prepared by the EUMETSAT Climate Monitoring Satellite Applications Facility from satellite observations of the visible channels of the MVIRI and SEVIRI instruments onboard the geostationary Meteosat satellites. The satellite SIS data are evaluated within the period 1984-2014 on various time scales: from individual months and years to long-term climate means. The validation is performed using the ground measurements of global solar radiation (GLBR) carried out on 11 meteorological stations of the Czech Hydrometeorological Institute in the Czech Republic with at least 30 years long data series. Our aim is to explore whether the SIS data could potentially serve as an alternative source of information on GLBR outside of a relatively sparse network of meteorological stations recording GLBR. Acknowledgement: Supported by the Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Program I (NPU I), grant number LO1415.

  15. Radiation exposure to the orbiting lunar station and lunar surface related to reusable nuclear shuttle operations

    Science.gov (United States)

    Hutchinson, P. I.

    1972-01-01

    The radiation environment created by the Reusable Nuclear Vehicle (RNS) in performing its normal mission functions while in the lunar vicinity and the impact of that environment on the Orbiting Lunar Station (OLS) and/or the lunar surface are examined. Lunar surface exposures from the operating reactor were evaluated for both the arrival and departure burns and while there is little probability that manned bases would lie along the paths in which measurable exposures would be recorded, the analyses do indicate the need to consider this possibility in planning such operations. Conclusions supported by the analyses and recommended operational constraints for the RNS are presented.

  16. Radiochemical analyses of surface water from U.S. Geological Survey hydrologic bench-mark stations

    Science.gov (United States)

    Janzer, V.J.; Saindon, L.G.

    1972-01-01

    The U.S. Geological Survey's program for collecting and analyzing surface-water samples for radiochemical constituents at hydrologic bench-mark stations is described. Analytical methods used during the study are described briefly and data obtained from 55 of the network stations in the United States during the period from 1967 to 1971 are given in tabular form.Concentration values are reported for dissolved uranium, radium, gross alpha and gross beta radioactivity. Values are also given for suspended gross alpha radioactivity in terms of natural uranium. Suspended gross beta radioactivity is expressed both as the equilibrium mixture of strontium-90/yttrium-90 and as cesium-137.Other physical parameters reported which describe the samples include the concentrations of dissolved and suspended solids, the water temperature and stream discharge at the time of the sample collection.

  17. A novel permanent gauge-cam station for surface-flow observations on the Tiber River

    Science.gov (United States)

    Tauro, Flavia; Petroselli, Andrea; Porfiri, Maurizio; Giandomenico, Lorenzo; Bernardi, Guido; Mele, Francesco; Spina, Domenico; Grimaldi, Salvatore

    2016-06-01

    Flow monitoring of riverine environments is crucial for hydrology and hydraulic engineering practice. Besides few experimental implementations, flow gauging relies on local water level and surface-flow velocity measurements through ultrasonic meters and radars. In this paper, we describe a novel permanent gauge-cam station for large-scale and continuous observation of surface flows, based on remote acquisition and calibration of video data. Located on the Tiber River, in the center of Rome, Italy, the station captures 1 min videos every 10 min over an area oriented along the river cross section of up to 20.6 × 15.5 m2. In a feasibility study, we demonstrate that accurate surface-flow velocity estimations can be obtained by analyzing experimental images via particle tracking velocimetry (PTV). In medium illumination conditions (70-75 lux), PTV leads to velocity estimations in close agreement with radar records and is less affected by uneven lighting than large-scale particle image velocimetry. Future efforts will be devoted to the development of a comprehensive test bed infrastructure for investigating the potential of multiple optics-based approaches for surface hydrology.

  18. Data Collected in 1959 by English Research Vessels at Serial and Surface Hydrographic Stations (NODC Accession 6900852)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The present volume contains data collected in 1959 by English research vessels at serial and surface hydrographic stations. The data list are preceded by a number of...

  19. Snow on the Ross Ice Shelf: comparison of reanalyses and observations from automatic weather stations

    Directory of Open Access Journals (Sweden)

    L. Cohen

    2013-03-01

    Full Text Available An analysis of precipitation from the ECMWF ERA-Interim and NCEP/NCAR Reanalysis-2 datasets is developed using snow accumulation measurements from Automatic Weather Stations (AWS around the Ross Ice Shelf (RIS, Antarctica. The high temporal resolution of the AWS snow accumulation measurements allow for a new, event-based comparison of reanalyses precipitation to in-situ observations. Snow accumulation records from nine AWS provide multiple years of accumulation data between 2008–2012 over a relatively large, homogeneous region of Antarctica and provide the basis for a statistical evaluation of accumulation events. The analysis shows that ERA-Interim reproduces significantly more precipitation events than NCEP-2 and these events correspond to an average 8.2% more precipitation. Correlations between reanalyses and AWS event sizes are seen at several stations (at > 90% significance levels and show that ERA-Interim consistently produces larger precipitation events than NCEP-2. The significant and complex effects of wind on snow accumulation (which can both limit and enhance accumulation make determining biases in the reanalyses data not possible with the AWS data, however the analysis does illustrate significant and important differences between ERA-Interim and NCEP-2 precipitation.

  20. A Comparison of OMPS Total Column Ozone Data with Data from Ground Stations

    Science.gov (United States)

    Labow, G. J.; McPeters, R. D.; Yang, E. S.; Haffner, D. P.

    2015-12-01

    The total column ozone dataset from Suomi NPP Ozone Mapping Profiler Suite (OMPS) has been recently reprocessed with new instrument calibrations. An overview will be presented systematically comparing ozone values to an ensemble of Brewer and Dobson spectrophotometers. The comparisons were made as a function of latitude, solar zenith angle, reflectivity and total ozone. The nadir mapper overpass data are derived from the single best match measurement, almost always located within one degree of the ground station and usually made within an hour and half of local noon. The total column ozone measurements from the Nadir Profiler instrument have also been compared to the ground-based measurements and these results will also be shown. An additional level 3 gridded product, 1 degree by 1 degree has been produced with corrections implemented in order to minimize the cross-track biases. This corrected data set yields a less noisy product and a smoother gridded ozone map.

  1. Detecting climate rationality and homogeneities of sea surface temperature data in Longkou marine station using surface air temperature

    Science.gov (United States)

    Li, Yan; Li, Huan; Wang, Qingyuan; Wang, Guosong; Fan, Wenjing

    2017-08-01

    This study presents a systematic evaluation of the climate rationality and homogeneity of monthly sea surface temperature (SST) in Longkou marine station from 1960 to 2011. The reference series are developed using adjacent surface air temperature (SAT) on a monthly timescale. The results suggest SAT as a viable option for use in evaluating climate rationality and homogeneity in the SST data on the coastal China Seas. According to the large-scale atmospheric circulation patterns and SAT of the adjacent meteorological stations, we confirm that there is no climate shift in 1972/1973 and then the climate shift in 1972/1973 is corrected. Besides, the SST time series has serious problems of inhomogeneity. Three documented break points have been checked using penalized maximum T (PMT) test and metadata. The changes in observation instruments and observation system are the main causes of the break points. For the monthly SST time series, the negative adjustments may be greatly due to the SST decreasing after automation. It is found that the increasing trend of annual mean SST after adjustment is higher than before, about 0.24 °C/10 yr.

  2. Service functions of private community health stations in China: A comparison analysis with government-sponsored community health stations.

    Science.gov (United States)

    Hou, Wanli; Fan, Hong; Xu, Jing; Wang, Fang; Chai, Yun; Xu, Hancheng; Li, Yongbin; Liu, Liqun; Wang, Bin; Jin, Jianqiang; Lu, Zuxun

    2012-04-01

    In China, with the restructuring of health care system moving forward, private community health facilities have been playing a complementary but increasingly important role in providing public health and basic medical care services in urban areas. However, only limited evidence is available concerning the service functions of private community health facilities in China. The aim of this study was to explore the functions of private community health stations (PCHSs) to provide evidence-based recommendations for policy-making and practice in the development of urban community health services systems. A total of 818 PCHSs and 4320 government-sponsored community health stations (GCHSs) located in 28 cities of China were investigated in 2008. The percentages of stations that provided health services and the annual workload per community health worker (CHW) were compared between the two types of institutions. The results showed that the percentages of PCHSs providing public health services were significantly higher than those of GCHSs (Pservices providing between PCHSs and GCHSs (P>0.05). The annual workloads of all the public health services and basic medical services per CHW in PCHSs were lighter than those in GCHSs (Peducation materials distribution (P>0.05). At present, the GCHSs are still the mainstream in urban China, which will last for a long period in future. However, our findings showed that the annual workloads of CHWs in PCHSs were no heavier than those in GCHSs, and the PCHSs were willing to provide public health services. In view of current inadequacy of health resources in China, it is feasible to further develop PCHSs under the guidance of the government, given that PCHSs can perform the basic functions of community health services, which is useful for the formation of public-private partnerships (PPP) and the improvement of community health services.

  3. Retrieving 4-dimensional atmospheric boundary layer structure from surface observations and profiles over a single station

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Zhaoxia [Univ. of Utah, Salt Lake City, UT (United States)

    2015-10-06

    Most routine measurements from climate study facilities, such as the Department of Energy’s ARM SGP site, come from individual sites over a long period of time. While single-station data are very useful for many studies, it is challenging to obtain 3-dimensional spatial structures of atmospheric boundary layers that include prominent signatures of deep convection from these data. The principal objective of this project is to create realistic estimates of high-resolution (~ 1km × 1km horizontal grids) atmospheric boundary layer structure and the characteristics of precipitating convection. These characteristics include updraft and downdraft cumulus mass fluxes and cold pool properties over a region the size of a GCM grid column from analyses that assimilate surface mesonet observations of wind, temperature, and water vapor mixing ratio and available profiling data from single or multiple surface stations. The ultimate goal of the project is to enhance our understanding of the properties of mesoscale convective systems and also to improve their representation in analysis and numerical simulations. During the proposed period (09/15/2011–09/14/2014) and the no-cost extension period (09/15/2014–09/14/2015), significant accomplishments have been achieved relating to the stated goals. Efforts have been extended to various research and applications. Results have been published in professional journals and presented in related science team meetings and conferences. These are summarized in the report.

  4. Validation of three satellite-derived databases of surface solar radiation using measurements performed at 42 stations in Brazil

    Science.gov (United States)

    Thomas, Claire; Wey, Etienne; Blanc, Philippe; Wald, Lucien

    2016-06-01

    The SoDa website (www.soda-pro.com) is populated with numerous solar-related Web services. Among them, three satellite-derived irradiation databases can be manually or automatically accessed to retrieve radiation values within the geographical coverage of the Meteosat Second Generation (MSG) satellite: the two most advanced versions of the HelioClim-3 database (versions 4 and 5, respectively HC3v4 and HC3v5), and the CAMS radiation service. So far, these databases have been validated against measurements of several stations in Europe and North Africa only. As the quality of such databases depends on the geographical regions and the climates, this paper extends this validation campaign and proposes an extensive comparison on Brazil and global irradiation received on a horizontal surface. Eleven stations from the Brazilian Institute of Space Research (INPE) network offer 1 min observations, and thirty-one stations from the Instituto Nacional de Meteorologia (INMET) network offer hourly observations. The satellite-derived estimates have been compared to the corresponding observations on hourly, daily and monthly basis. The bias relative to the mean of the measurements for HC3v5 is mostly comprised between 1 and 3 %, and that for HC3v4 between 2 and 5 %. These are very satisfactory results and they demonstrate that HC3v5, and to a lesser extent HC3v4, may be used in studies of long-term changes in SSI in Brazil. The situation is not so good with CAMS radiation service for which the relative bias is mostly comprised between 5 and 10 %. For hourly irradiation, the relative RMSE ranges from 15 to 33 %. The correlation coefficient is very large for all stations and the three databases, with an average of 0.96. The three databases reproduce well the hour from hour changes in SSI. The errors show a tendency to increase with the viewing angle of the MSG satellite. They are greater in tropical areas where the relative humidity in the atmosphere is important. It is concluded

  5. The study of single station inverting the sea surface current by HF ground wave radar based on adjoint assimilation technology

    Science.gov (United States)

    Han, Shuzong; Yang, Hua; Xue, Wenhu; Wang, Xingchi

    2017-06-01

    This paper introduces the assimilation technology in an ocean dynamics model and discusses the feasibility of inverting the sea surface current in the detection zone by assimilating the sea current radial velocity detected by single station HF ground wave radar in ocean dynamics model. Based on the adjoint assimilation and POM model, the paper successfully inverts the sea surface current through single station HF ground wave radar in the Zhoushan sea area. The single station HF radar inversion results are also compared with the bistatic HF radar composite results and the fixed point measured results by Annderaa current meter. The error analysis shows that acquisition of flow velocity and flow direction data from the single station HF radar based on adjoint assimilation and POM model is viable and the data obtained have a high correlation and consistency with the flow field observed by HF radar.

  6. Evaluation of representativeness of near-surface winds in station measurements, global and regional reanalysis for Germany

    Science.gov (United States)

    Kaspar, Frank; Kaiser-Weiss, Andrea K.; Heene, Vera; Borsche, Michael; Keller, Jan

    2015-04-01

    Within the preparation activities for a European COPERNICUS Climate Change Service (C3S) several ongoing research projects analyse the potential of global and regional model-based climate reanalyses for applications. A user survey in the FP7-project CORE-CLIMAX revealed that surface wind (10 m) is among the most frequently used parameters of global reanalysis products. The FP7 project UERRA (Uncertainties in Ensembles of Regional Re-Analysis) has the focus on regional European reanalysis and the associated uncertainties, also from a user perspective. Especially in the field of renewable energy planning and production there is a need for climatological information across all spatial scales, i.e., from climatology at a certain site to the spatial scale of national or continental renewable energy production. Here, we focus on a comparison of wind measurements of the Germany's meteorological service (Deutscher Wetterdienst, DWD) with global reanalyses of ECWMF and a regional reanalysis for Europe based on DWD's NWP-model COSMO (performed by the Hans-Ertel-Center for Weather Research, University of Bonn). Reanalyses can provide valuable additional information on larger scale variability, e.g. multi-annual variation over Germany. However, changes in the observing system, model errors and biases have to be carefully considered. On the other hand, the ground-based observation networks partly suffer from change of the station distribution, changes in instrumentation, measurements procedures and quality control as well as local changes which might modify their spatial representativeness. All these effects might often been unknown or hard to characterize, although plenty of the meta-data information has been recorded for the German stations. One focus of the presentation will be the added-value of the regional reanalysis.

  7. Different Multifractal Scaling of the 0 cm Average Ground Surface Temperature of Four Representative Weather Stations over China

    Directory of Open Access Journals (Sweden)

    Lei Jiang

    2013-01-01

    Full Text Available The temporal scaling properties of the daily 0 cm average ground surface temperature (AGST records obtained from four selected sites over China are investigated using multifractal detrended fluctuation analysis (MF-DFA method. Results show that the AGST records at all four locations exhibit strong persistence features and different scaling behaviors. The differences of the generalized Hurst exponents are very different for the AGST series of each site reflecting the different scaling behaviors of the fluctuation. Furthermore, the strengths of multifractal spectrum are different for different weather stations and indicate that the multifractal behaviors vary from station to station over China.

  8. Land Surface-atmosphere Exchange In The Natural Landscapes(on The Cabauw Station)

    Science.gov (United States)

    Panin, G.; Kohsiek, W.; Nasonov, A.; Bernhofer, Ch.

    In line with earlier observations the Cabauw data (17568 half hour fluxes) show imbal- ances of the energy budget 50-200 W/m2 during daytime conditions. Measurements of all components of the balance equation of heat, averaged over half hour periods, show that, within the framework of the used measuring techniques, the heat balance is not closed. The sum of fluxes of heat LE+H which is going into the atmosphere is less than Rn-G. The main cause of this systematic imbalance is not the experimental methodol- ogy but a conceptual deficiency. It is related to the fact that the energy-mass exchange between the complex (horizontally inhomogeneous) land surface and the atmosphere is determined by applying theories that are based on the hypothesis of stationary and horizontal homogeneity (SHH). Using the experimental results of the Cabauw station, it was detected that the underestimation of the turbulent fluxes is related to the ter- rain inhomogeneity. To systematize the correction for this effect a parameterization is suggested which empirically makes use of the involved inhomogenity scale in the environment of a site. This parameterization incorporates seasonal and wind direction effects. For parameterization of the energy imbalance the coefficient Kf is proposed. This coefficient can be interpreted as a measure of inhomogeneity and supposedly compromises the low frequency range of the covariance spectrum and possibly other coherent fluxes escaping covariance flux measurements, and serves as an expression of inhomogeneity and nonstationarity (INH). The average value Kf of the Cabauw station is in line with the data of FIFE, KUREX TARTEX and SADE. The paper aims to serve as a contribution to the ongoing discussion on how to account for different types and scales of land surface inhomogeneities inside cells of models such as global climate models, as well as mesoscale models.

  9. Surface wave tomography of central and northern Europe from automated inter-station dispersion measurements

    Science.gov (United States)

    Soomro, R. A.; Weidle, C.; Lebedev, S.; Cristiano, L.; Meier, T. M.

    2013-12-01

    With the rapid growth in the no. of seismic stations globally, manual data processing for routine analysis as well as determination of seismic observables becomes more and more impractical. Therefore, automated schemes are inevitable to handle these large data volumes. For surface wave tomography, phase velocity dispersion curves of fundamental mode surface waves yield information on the isotropic as well as anisotropic structure of the crust and upper mantle. We measure inter-station phase velocity dispersion curves through cross correlation of vertical component (Rayleigh wave) and transverse component (Love wave) seismograms. We have developed a scheme to automate this well established inter-station method, which automatically selects the smooth parts of observed phase velocity dispersion curves, and thus obtain path average phase velocity dispersion curve of each inter-station path. After testing various parameters for automation of the procedure we finally confined the method to three parameters only, namely (1) difference of the measured phase velocity curve from a background model, (2) a smoothness constraint and (3) a length criterion. We performed rigorous tests to optimize the parameters and obtained optimal values of these three parameters. We successfully applied the method to more than one hundred thousand inter station paths in central and northern Europe which involved more than one million cross correlations on 20 years of the data of the permanent networks. The method was also tested on temporary deployments e.g. TOR, PASSEQ, SVEKALPKO etc, across Europe. After inversion of the fundamental mode phase velocity dispersion curves for both Rayleigh and Love waves, we obtain high resolution anisotropic phase velocity maps for periods between 10 and 250 seconds with a lateral resolution between about 50 to 100 kilometers. Well known features of upper mantle structure in central Europe are well resolved in our phase velocity maps. Distinct differences

  10. Comparison of conventional vs. modular hydrogen refueling stations and on-site production vs. delivery.

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Ethan S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Pratt, Joseph William [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-03-01

    To meet the needs of public and private stakeholders involved in the development, construction, and operation of hydrogen fueling stations needed to support the widespread roll-out of hydrogen fuel cell electric vehicles, this work presents publicly available station templates and analyses. These ‘Reference Stations’ help reduce the cost and speed the deployment of hydrogen stations by providing a common baseline with which to start a design, enable quick assessment of potential sites for a hydrogen station, identify contributors to poor economics, and suggest areas of research. This work presents layouts, bills of materials, piping and instrumentation diagrams, and detailed analyses of five new station designs. In the near term, delivered hydrogen results in a lower cost of hydrogen compared to on-site production via steam methane reforming or electrolysis, although the on-site production methods have other advantages. Modular station concepts including on-site production can reduce lot sizes from conventional assemble-on-site stations.

  11. Geostatistical improvements of evapotranspiration spatial information using satellite land surface and weather stations data

    Science.gov (United States)

    de Carvalho Alves, Marcelo; de Carvalho, Luiz Gonsaga; Vianello, Rubens Leite; Sediyama, Gilberto C.; de Oliveira, Marcelo Silva; de Sá Junior, Arionaldo

    2013-07-01

    The objective of the present study was to use the simple cokriging methodology to characterize the spatial variability of Penman-Monteith reference evapotranspiration and Thornthwaite potential evapotranspiration methods based on Moderate Resolution Imaging Spetroradiometer (MODIS) global evapotranspiration products and high-resolution surfaces of WordClim temperature and precipitation data. The climatic element data referred to 39 National Institute of Meteorology climatic stations located in Minas Gerais state, Brazil and surrounding states. The use of geostatistics and simple cokriging technique enabled the characterization of the spatial variability of the evapotranspiration providing uncertainty information on the spatial prediction pattern. Evapotranspiration and precipitation surfaces were implemented for the climatic classification in Minas Gerais. Multivariate geostatistical determined improvements of evapotranspiration spatial information. The regions in the south of Minas Gerais derived from the moisture index estimated with the MODIS evapotranspiration (2000-2010), presented divergence of humid conditions when compared to the moisture index derived from the simple kriged and cokriged evapotranspiration (1961-1990), indicating climate change in this region. There was stronger pattern of crossed covariance between evapotranspiration and precipitation rather than temperature, indicating that trends in precipitation could be one of the main external drivers of the evapotranspiration in Minas Gerais state, Brazil.

  12. Surface Charging Controlling of the Chinese Space Station with Hollow Cathode Plasma Contactor

    Science.gov (United States)

    Jiang, Kai; Wang, Xianrong; Qin, Xiaogang; Yang, Shengsheng; Yang, Wei; Zhao, Chengxuan; Chen, Yifeng; Shi, Liang; Tang, Daotan; Xie, Kan

    2016-07-01

    A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging. In this article, the controlling of surface charging on Chinese Space Station (CSS) is investigated, and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma contactor. The analysis is obtained that the high voltage (HV) solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed, when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.

  13. Influence of soil moisture content on surface albedo and soil thermal parameters at a tropical station

    Science.gov (United States)

    Sugathan, Neena; Biju, V.; Renuka, G.

    2014-06-01

    Half hourly data of soil moisture content, soil temperature, solar irradiance, and reflectance are measured during April 2010 to March 2011 at a tropical station, viz., Astronomical Observatory, Thiruvananthapuram, Kerala, India (76°59'E longitude and 8°29'N latitude). The monthly, seasonal and seasonal mean diurnal variation of soil moisture content is analyzed in detail and is correlated with the rainfall measured at the same site during the period of study. The large variability in the soil moisture content is attributed to the rainfall during all the seasons and also to the evaporation/movement of water to deeper layers. The relationship of surface albedo on soil moisture content on different time scales are studied and the influence of solar elevation angle and cloud cover are also investigated. Surface albedo is found to fall exponentially with increase in soil moisture content. Soil thermal diffusivity and soil thermal conductivity are also estimated from the subsoil temperature profile. Log normal dependence of thermal diffusivity and power law dependence of thermal conductivity on soil moisture content are confirmed.

  14. Influence of soil moisture content on surface albedo and soil thermal parameters at a tropical station

    Indian Academy of Sciences (India)

    Neena Sugathan; V Biju; G Renuka

    2014-07-01

    Half hourly data of soil moisture content, soil temperature, solar irradiance, and reflectance are measured during April 2010 to March 2011 at a tropical station, viz., Astronomical Observatory, Thiruvananthapuram, Kerala, India (76° 59’E longitude and 8°29’N latitude). The monthly, seasonal and seasonal mean diurnal variation of soil moisture content is analyzed in detail and is correlated with the rainfall measured at the same site during the period of study. The large variability in the soil moisture content is attributed to the rainfall during all the seasons and also to the evaporation/movement of water to deeper layers. The relationship of surface albedo on soil moisture content on different time scales are studied and the influence of solar elevation angle and cloud cover are also investigated. Surface albedo is found to fall exponentially with increase in soil moisture content. Soil thermal diffusivity and soil thermal conductivity are also estimated from the subsoil temperature profile. Log normal dependence of thermal diffusivity and power law dependence of thermal conductivity on soil moisture content are confirmed.

  15. Petrologic comparisons of Cayley and Descartes on the basis of Apollo 16 soils from stations 4 and 11

    Science.gov (United States)

    Basu, A.; Mckay, D. S.

    1984-01-01

    Petrologic aspects of the Cayley and Descartes formations are reviewed in the light of new data on Apollo 16 soils. Specific comparison of the modal abundances of lithic fragments in drive tube sample 64001/2 from the slopes of Stone Mountain (station 4) and in soil 67941 from the North Ray Crater rim (station 11) shows that melt rocks, especially poikilitic rocks, are more abundant at station 4 than at station 11; the reverse is true for fragmental breccias. Such lithologic differences suggest that stations 4 and 11 do not belong to the same geologic formation. Metamorphosed breccias are pervasive in both the formations and may represent a local component that has been reworked and diluted as fresh materials were added. Lithologic compositions inferred from the study of soil samples are different from lithologic compositions inferred from the study of rake samples or breccia clasts. This difference may be related to a mixing of material of different grain size distributions. The petrology of soils at the Apollo 16 site may not accurately reflect original material associated with either the Descartes or the Cayley formation because of extensive mixing with local material.

  16. Trends in Surface-Water Quality at Selected Ambient-Monitoring Network Stations in Kentucky, 1979-2004

    Science.gov (United States)

    Crain, Angela S.; Martin, Gary R.

    2009-01-01

    Increasingly complex water-management decisions require water-quality monitoring programs that provide data for multiple purposes, including trend analyses, to detect improvement or deterioration in water quality with time. Understanding surface-water-quality trends assists resource managers in identifying emerging water-quality concerns, planning remediation efforts, and evaluating the effectiveness of the remediation. This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the Kentucky Energy and Environment Cabinet-Kentucky Division of Water, to analyze and summarize long-term water-quality trends of selected properties and water-quality constituents in selected streams in Kentucky's ambient stream water-quality monitoring network. Trends in surface-water quality for 15 properties and water-quality constituents were analyzed at 37 stations with drainage basins ranging in size from 62 to 6,431 square miles. Analyses of selected physical properties (temperature, specific conductance, pH, dissolved oxygen, hardness, and suspended solids), for major ions (chloride and sulfate), for selected metals (iron and manganese), for nutrients (total phosphorus, total nitrogen, total Kjeldahl nitrogen, nitrite plus nitrate), and for fecal coliform were compiled from the Commonwealth's ambient water-quality monitoring network. Trend analyses were completed using the S-Plus statistical software program S-Estimate Trend (S-ESTREND), which detects trends in water-quality data. The trend-detection techniques supplied by this software include the Seasonal Kendall nonparametric methods for use with uncensored data or data censored with only one reporting limit and the Tobit-regression parametric method for use with data censored with multiple reporting limits. One of these tests was selected for each property and water-quality constituent and applied to all station records so that results of the trend procedure could be compared among

  17. Characterization of Aspergillus fumigatus Isolates from Air and Surfaces of the International Space Station.

    Science.gov (United States)

    Knox, Benjamin P; Blachowicz, Adriana; Palmer, Jonathan M; Romsdahl, Jillian; Huttenlocher, Anna; Wang, Clay C C; Keller, Nancy P; Venkateswaran, Kasthuri

    2016-01-01

    One mission of the Microbial Observatory Experiments on the International Space Station (ISS) is to examine the traits and diversity of fungal isolates to gain a better understanding of how fungi may adapt to microgravity environments and how this may affect interactions with humans in a closed habitat. Here, we report an initial characterization of two isolates, ISSFT-021 and IF1SW-F4, of Aspergillus fumigatus collected from the ISS and a comparison to the experimentally established clinical isolates Af293 and CEA10. Whole-genome sequencing of ISSFT-021 and IF1SW-F4 showed 54,960 and 52,129 single nucleotide polymorphisms, respectively, compared to Af293, which is consistent with observed genetic heterogeneity among sequenced A. fumigatus isolates from diverse clinical and environmental sources. Assessment of in vitro growth characteristics, secondary metabolite production, and susceptibility to chemical stresses revealed no outstanding differences between ISS and clinical strains that would suggest special adaptation to life aboard the ISS. Virulence assessment in a neutrophil-deficient larval zebrafish model of invasive aspergillosis revealed that both ISSFT-021 and IF1SW-F4 were significantly more lethal than Af293 and CEA10. Taken together, these genomic, in vitro, and in vivo analyses of two A. fumigatus strains isolated from the ISS provide a benchmark for future investigations of these strains and for continuing research on specific microbial isolates from manned space environments. IMPORTANCE As durations of manned space missions increase, it is imperative to understand the long-term consequence of microbial exposure on human health in a closed human habitat. To date, studies aimed at bacterial and fungal contamination of space vessels have highlighted species compositions biased toward hardy, persistent organisms capable of withstanding harsh conditions. In the current study, we assessed traits of two independent Aspergillus fumigatus strains isolated

  18. Draft Genome Sequences of Biosafety Level 2 Opportunistic Pathogens Isolated from the Environmental Surfaces of the International Space Station.

    Science.gov (United States)

    Checinska Sielaff, Aleksandra; Singh, Nitin K; Allen, Jonathan E; Thissen, James; Jaing, Crystal; Venkateswaran, Kasthuri

    2016-12-29

    The draft genome sequences of 20 biosafety level 2 (BSL-2) opportunistic pathogens isolated from the environmental surfaces of the International Space Station (ISS) were presented. These genomic sequences will help in understanding the influence of microgravity on the pathogenicity and virulence of these strains when compared with Earth strains.

  19. Confronting AeroCom models with particle size distribution data from surface in situ stations

    Science.gov (United States)

    Platt, Stephen; Fiebig, Markus; Mann, Graham; Schulz, Michael

    2016-04-01

    The size distribution is the most important property for describing any interaction of an aerosol particle population with its surroundings. In first order, it determines both, the aerosol optical properties quantifying the direct aerosol climate effect, and the fraction of aerosol particles acting as cloud condensation nuclei quantifying the indirect aerosol climate effect. Aerosol schemes of modern climate models resolve the aerosol particle size distribution (APSD) explicitly. In improving the skill of climate models, it is therefore highly useful to confront these models with precision APSD data observed at surface stations. Corresponding previous work focussed on comparing size integrated, seasonal particle concentrations at selected sites with ensemble model averages to assess overall model skill. Building on this work, this project intends to refine the approach by comparing median particle size and integral concentration of fitted modal size distributions. It will also look at skill differences between models in order to find reasons for matches and discrepancies. The presentation will outline the project, and will elaborate on input requested from modelling groups to participate in the exercise.

  20. Urban Climate Station Site Selection Through Combined Digital Surface Model and Sun Angle Calculations

    Science.gov (United States)

    Kidd, Chris; Chapman, Lee

    2012-01-01

    Meteorological measurements within urban areas are becoming increasingly important due to the accentuating effects of climate change upon the Urban Heat Island (UHI). However, ensuring that such measurements are representative of the local area is often difficult due to the diversity of the urban environment. The evaluation of sites is important for both new sites and for the relocation of established sites to ensure that long term changes in the meteorological and climatological conditions continue to be faithfully recorded. Site selection is traditionally carried out in the field using both local knowledge and visual inspection. This paper exploits and assesses the use of lidar-derived digital surface models (DSMs) to quantitatively aid the site selection process. This is acheived by combining the DSM with a solar model, first to generate spatial maps of sky view factors and sun-hour potential and second, to generate site-specific views of the horizon. The results show that such a technique is a useful first-step approach to identify key sites that may be further evaluated for the location of meteorological stations within urban areas.

  1. Derivation of GNSS derived station velocities for a surface deformation model in the Austrian region

    Science.gov (United States)

    Umnig, Elke; Weber, Robert; Maras, Jadre; Brückl, Ewald

    2016-04-01

    This contribution deals with the first comprehensive analysis of GNSS derived surface velocities computed within an observation network of about 100 stations covering the whole Austrian territory and parts of the neighbouring countries. Coordinate time series are available now, spanning a period of 5 years (2010.0-2015.0) for one focus area in East Austria and one and a half year (2013.5-2015.0) for the remaining part of the tracking network. In principle the data series are stemming from two different GNSS campaigns. The former was set up to investigate intra plate tectonic movements within the framework of the project ALPAACT (seismological and geodetic monitoring of ALpine-PAnnonian ACtive Tectonics), the latter was designed to support a number of various requests, e.g. derivation of GNSS derived water vapour fields, but also to expand the foresaid tectonic studies. In addition the activities within the ALPAACT project supplement the educational initiative SHOOLS & QUAKES, where scholars contribute to seismological research. For the whole period of the processed coordinate time series daily solutions have been computed by means of the Bernese software. The processed coordinate time series are tied to the global reference frame ITRF2000 as well as to the frame ITRF2008. Due to the transition of the reference from ITRF2000 to ITRF2008 within the processing period, but also due to updates of the Bernese software from version 5.0 to 5.2 the time series were initially not fully consistent and have to be re-aligned to a common frame. So the goal of this investigation is to derive a nationwide consistent horizontal motion field on base of GNSS reference station data within the ITRF2008 frame, but also with respect to the Eurasian plate. In this presentation we focus on the set-up of the coordinate time series and on the problem of frame alignment. Special attention is also paid to the separation into linear and periodic motion signals, originating from tectonic or non

  2. Comparison among sea surface roughness schemes

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the measurements from the US National Data Buoy Center 3-m discus buoy site No.44004 (38.5°N, 70.47°W) from January 1 to March 31 of 2003, with the COARE algorithm (Version 3.0), the results from four parameterization schemes developed recently for sea surface aerodynamic roughness length were compared with each other. Calculations of frictional speed u*, drag coefficient Cd and wind stress τ indicate that the calculated frictional velocities from the four schemes (8.50%-16.20%, the normalized standard error estimate, or NSEE), the computed drag coefficients and wind stress (respectively 15.08%-28.67% and 17.26%-50.59% NSEE) are reasonable. Schemes YT96 and GW03 are consistent. The O02 scheme gives overestimated values for u* and Cd. Schemes TY01 and GW03 display discontinuous characteristics in handling young wave data.

  3. Multi-decadal Surface Temperature Trends and Extremes at Arctic Stations

    Science.gov (United States)

    Uttal, T.; Makshtas, A.

    2015-12-01

    The Arctic region is considered to be one where global temperatures are changing the most quickly; a number of factors make it the region where an accurate determination of surface temperature is the most difficult to measure or estimate. In developing a pan-Arctic perspective on Arctic in-situ temperature variability, several issues must be addressed including accounting for the different lengths of temperature records at different locations when comparing trends, accounting for the steep latitudinal controls on 'seasonal' trends, considering the often significant variability between different (sometimes a multitude) of temperature measurements made in the vicinity of a single station, and loss of detail information when data is ingested in a global archives or interpolated into gridded data sets. The International Arctic Systems for Observing the Atmosphere (www.iasoa.org) is an internationally networked consortium of facilities that measure a wide range of meteorological and climate relevant parameters; temperature is the most fundamental of these parameters. Many of the observatories have the longest temperature records in the Arctic region including Barrow, Alaska (114 years), Tiksi, Russia (83 years), and Eureka, Canada (67 years). Using the IASOA data sets a detailed analysis is presented of temperature trends presented as a function of the beginning date from which the trend is calculated, seasonal trends considered in the context of the extreme Arctic solar ephemeris, and the variability in occurrence of annual extreme temperature events. At the Tiksi observatory, a complete record is available of 3-hourly temperatures 1932 to present that was constructed through digitization of decades of written records. This data set is used to investigate if calculated trends and variabilities are consistent with those calculated from daily minimum and maximum values archived by the NOAA National Centers for Environmental Information Global Historical Climatology

  4. 张江台地表与深井地震观测对比分析%Comparative Analysis of Zhangjiang Station Surface and Deep Seismic Observation

    Institute of Scientific and Technical Information of China (English)

    裴晓; 尹继尧; 杨庭春

    2013-01-01

    tools.In this study,the micro-tremor and dynamic range data of the Zhangjiang surface station and deep well station data are compared and analyzed systematically.We obtained the following preliminary results:The root mean square(RMS)value of background noise in the deep well is smaller in orders of magnitude than that at the surface station.It can accurately record micro-tremors because of only slight disturbances by the external environment.The seismic signals of deep well observation are the most accurate.The dynamic range of measurement stations effectively reflects the instrument's performance indicators to determine the background environment interference level recorded by the maximum dynamic range of the seismic signal.Due to the superposition station environment noise and seismic signal,the instrument is not up to the dynamic range of design and can only achieve an effective dynamic range of measurement.The effective dynamic range of the deep well station exceeds 30% of that of surface stations; therefore,it can produce a broader range of micro-tremors.Range surface frequency is within 0.3~2.5; the deep well station has low-frequency noise and nearly high-frequency at 25 Hz.A comparison of deep bench surface stations reveals that environment noise is much smaller,particularly in the low-frequency range.Moreover,with reference to analysis of data from the Shanghai telemetry seismic network of various types of base background noise,the dynamic range of noise at the Zhangjiang comprehensive deep well and those of the Shanghai network deep wells are consistent.Therefore,comprehensive visible data for the deep seismic section is unaffected by the noise integrated system.With the accelerated process of city development,environmental noise will increase; therefore,the deep well seismometer observation method is more reliable than surface seismometer observation.Completed construction of the seismic section of the deep borehole project can provide greater precision

  5. Coastal Boundary Layer Characteristics of Wind, Turbulence, and Surface Roughness Parameter over the Thumba Equatorial Rocket Launching Station, India

    Directory of Open Access Journals (Sweden)

    K. V. S. Namboodiri

    2014-01-01

    Full Text Available The study discusses the features of wind, turbulence, and surface roughness parameter over the coastal boundary layer of the Peninsular Indian Station, Thumba Equatorial Rocket Launching Station (TERLS. Every 5 min measurements from an ultrasonic anemometer at 3.3 m agl from May 2007 to December 2012 are used for this work. Symmetries in mesoscale turbulence, stress off-wind angle computations, structure of scalar wind, resultant wind direction, momentum flux (M, Obukhov length (L, frictional velocity (u*, w-component, turbulent heat flux (H, drag coefficient (CD, turbulent intensities, standard deviation of wind directions (σθ, wind steadiness factor-σθ relationship, bivariate normal distribution (BND wind model, surface roughness parameter (z0, z0 and wind direction (θ relationship, and variation of z0 with the Indian South West monsoon activity are discussed.

  6. Comparison of different poultry breeds under station and on-farm conditions in Ethiopia

    NARCIS (Netherlands)

    Wondmeneh, E.; Waaij, Van der E.H.; Udo, H.M.J.; Tadelle, D.; Arendonk, Van J.A.M.

    2016-01-01

    A selective breeding program was implemented to improve the performance of indigenous chickens. Improved chicken from the 7th generation was compared with commercial layer, crossbred and unselected indigenous chickens both on-station and on-farm. A total of 870 chickens were used. More than 600

  7. COMPARISON BETWEEN MULTICOPTER UAV AND TOTAL STATION FOR ESTIMATING STOCKPILE VOLUMES

    Directory of Open Access Journals (Sweden)

    C. Arango

    2015-08-01

    Full Text Available Currently the UAV (Unmanned Aerial Vehicle have become an alternative for different engineering applications, especially in surveying, one of these applications is the calculation of volumes of stockpiled material, but there are questions about its accuracy and efficiency, the purpose of this article is to compare traditional surveying methods for estimating total volumes through data obtained by total stations and data obtained by a multicopter UAV. In order to answer these questions we obtain data from the same location and the results were compared. After comparing the results it was found that there was a 2,88% difference between the volume calculated with the total station data and the actual volume, and −0,67% difference between the volume calculated with the UAV data and the actual volume, concluding that the estimated volume with UAV data is more accurate.

  8. Comparison of solid shapes geometry derived by a laser scanner and a total station

    Science.gov (United States)

    Sidiropoulos, Andreas; Lakakis, Konstantinos

    2016-08-01

    The laser scanning technology has become a common method for the daily applications of a large variety of scientists and professionals. Even for more sophisticated projects, laser scanners have been proved a very useful tool at researchers' and engineers' disposal. In this paper, we investigated the ability of a laser scanner compared to the ability of a total station to provide the geometry of solids. The tests were made in the laboratory facilities of the Aristotle University of Thessaloniki, in a variety of distances between the measuring instrument and the object. The solids that were used differ in shape, material and color. The objects are a wooden cube, a metal cube and a wooden pyramid. The absolute dimensions of the solid shapes were provided by the use of a caliper and were compared to the dimensions that were calculated by the coordinates produced by the total station and laser scanner measurements.

  9. Tidal and non-tidal contributions to surface loading processes on station coordinates

    OpenAIRE

    Mendes Cerveira, Paulo Jorge

    2007-01-01

    Paulo Jorge Mendes Cerveira Zsfassung in dt. Sprache Wien, Techn. Univ., Diss., 2006 OeBB Auch erschienen in: Journal of Geodynamics, Mendes Cerveira, P.J., R. Heinkelmann, J. Boehm, R. Weber and H. Schuh, (2006a), Contributions of GPS and VLBI in understanding station motions, DOI:10.1016/j.jog.2005.08.024, pp. 87-93.

  10. SURF'S UP! – Protein classification by surface comparisons

    Indian Academy of Sciences (India)

    Joanna M Sasin; Adam Godzik; Janusz M Bujnicki

    2007-01-01

    Large-scale genome sequencing and structural genomics projects generate numerous sequences and structures for ‘hypothetical’ proteins without functional characterizations. Detection of homology to experimentally characterized proteins can provide functional clues, but the accuracy of homology-based predictions is limited by the paucity of tools for quantitative comparison of diverging residues responsible for the functional divergence. SURF’S UP! is a web server for analysis of functional relationships in protein families, as inferred from protein surface maps comparison according to the algorithm. It assigns a numerical score to the similarity between patterns of physicochemical features (charge, hydrophobicity) on compared protein surfaces. It allows recognizing clusters of proteins that have similar surfaces, hence presumably similar functions. The server takes as an input a set of protein coordinates and returns files with ``spherical coordinates” of proteins in a PDB format and their graphical presentation, a matrix with values of mutual similarities between the surfaces, and the unrooted tree that represents the clustering of similar surfaces, calculated by the neighbor-joining method. SURF’S UP! facilitates the comparative analysis of physicochemical features of the surface, which are the key determinants of the protein function. By concentrating on coarse surface features, SURF’S UP! can work with models obtained from comparative modelling. Although it is designed to analyse the conservation among homologs, it can also be used to compare surfaces of non-homologous proteins with different three-dimensional folds, as long as a functionally meaningful structural superposition is supplied by the user. Another valuable characteristic of our method is the lack of initial assumptions about the functional features to be compared. SURF’S UP! is freely available for academic researchers at http://asia.genesilico.pl/surfs_up/.

  11. Use of floating surface detector stations for the calibration of a deep-sea neutrino telescope

    CERN Document Server

    Tsirigotis, A G; Gizani, N A B; Leisos, A; Tzamarias, S E; 10.1016/j.nima.2008.07.011

    2011-01-01

    We propose the operation of floating Extensive Air Shower (EAS) detector stations in coincidence with the KM3NeT Mediterranean deep-sea neutrino telescope to determine the absolute position and orientation of the underwater detector and to investigate possible systematic angular errors. We evaluate the accuracy of the proposed calibration strategies using a detailed simulation of the EAS and KM3NeT detectors.

  12. Comparison of Ambient Noise From Two Station Designs, Evaluating USArray's Transportable and Flexible Arrays in the Pacific Northwest

    Science.gov (United States)

    Pfeifer, M.; Alvarez, M.; Woodward, R.; Yang, Z.

    2009-12-01

    The USArray program within the National Science Foundation-funded Earthscope program is comprised of two portable broadband seismic projects; the Transportable Array (TA), and the Flexible Array (FA). The TA consists of 400 stations occupy locations within the United States on a nominal 70 km spacing for a period of approximately 24 months. As a network, these TA stations roll from west to east so that within 10 years the entire lower 48 states will have been occupied by the TA network. As a complementary component of USArray, the FA pool of instruments is comprised of 1200 active-source, 120 short-period and 326 broadband portable stations. These instruments are used by Principal Investigator-driven studies which focus on geologic targets within the TA footprint. Currently the TA network is transitioning from the Rocky Mountains into the Great Plains. The FA currently has four experiments installed. In this study we quantify the overall performance of these two tandem networks using a controlled set of continuous recordings in Western Washington. We compare the background noise levels between the standard deep TA and shallow FA broadband sensor vault system. We use McNamara’s probability density function (PDF) analysis as the basis of the comparison. We combine the network wide PDF’s of each network for a period of over 600 days of contemporaneous recordings. Preliminary analysis using data from 28 TA stations in western Washington and 47 nearby FA stations from the CAFE experiment (Abers, et al. Eos Trans. AGU 88(52), Fall Meet. Suppl. S43D-07), show that the TA stations are quieter at periods below 20 seconds by about 12 dB on the horizontal components. The vertical components for both the TA and FA are equivalent for periods below 5 seconds. At higher frequencies (> 2 Hz), however, the FA shallower vault is quieter by approximately 10 dB on both the vertical and horizontal components. The question addressed is, what is contributing to the difference in

  13. Absorbing aerosols: are they causing a delayed sunrise? A comparison between plain and plateau IGB stations

    Science.gov (United States)

    Kumari, Lipi

    2016-07-01

    Current study tries to compare black carbon radiative effects at densely populated plain station Varanasi and lesser populated plateau station Ranchi with large forest cover but with numerous open coal mines. While average black carbon mass density (BC) reduced from February to March at Ranchi following an increase in convective instability, it was observed to increase by 150% from Feb to March at Varanasi, as transport from NE forest fires increases. It is observed that absorption due to black carbon of non-fossil fuel origin is prevalent throughout the day at Varanasi, while this contribution is most significant during post sunset hours at Ranchi. Radiative forcing, estimated hourly using chemical model (to derive BC-aod ) and radiative transfer model, indicated that at least 5% of the incoming radiation is always cut-off during any time of the day at Varanasi while this is about 4% at Ranchi. BC effectively causes a delayed sunrise by reducing the incoming radiation at plains of IGB by around 25% which may be crucial for bionetwork.

  14. Habitat Modeling in Complex Streams: Comparison of Terrestrial Laser Scanning and Traditional Surveying Techniques for Topographic Surface Generation

    Science.gov (United States)

    Hession, W. C.; Kozarek, J. L.; Resop, J. P.

    2009-12-01

    Accurate stream topography measurement is important for many environmental and ecological applications, such as hydraulic modeling and habitat characterization. Topological surveys are commonly created from point measurements using methods such as total station or global positioning system (GPS) surveying. However, surveying can be time intensive and limited by poor spatial resolution and difficulty in measuring complex morphology such as boulder-filled mountain streams. This can lead to measurement and interpolation errors, which can propagate to model uncertainty. Terrestrial laser scanning (TLS) has the potential to create high resolution, high accuracy topographic maps. Two methods, total station surveying and TLS, were used to measure the topography for an 80-meter forested reach on the Staunton River in Shenandoah National Park, Virginia, USA. The 2,500 surveyed points were directly compared to the TLS point cloud (approximately 9,500,000 points). The total station and TLS datasets were processed to create unique digital elevation models (DEM) of the stream reach. The resulting DEMs were used to evaluate uncertainties in topographic surfaces due to errors in traditional surveying techniques, to evaluate the propagation of uncertainty due to these errors in habitat modeling, and to evaluate the efficacy of utilizing TLS for complex, boulder streams. Comparison of resulting topography of a complex boulder stream using terrestrial laser scanning (grey-scale surfaces) and total station surveying (grid lines).

  15. Reconstruction of erythemal UV-levels for two stations in Austria: a comparison between alpine and urban regions

    Directory of Open Access Journals (Sweden)

    H. E. Rieder

    2008-01-01

    Full Text Available The aim of this study is the reconstruction of past UV-radiation doses for two stations in Austria, Hoher Sonnblick and Vienna, using a physical radiation transfer model. The method uses the modeled UV-radiation under clear-sky conditions, cloud modification factors and a correction factor as input variables. To identify the influence of temporal resolution of input data and modification factors, an ensemble of four different modelling approaches has been calculated, each with hourly or daily resolution. This is especially important because we found no other study describing the influence of the temporal resolution of input data on model performance. Following the results of the statistical analysis of the evaluation period the model with the highest temporal resolution has been chosen for the reconstruction of the UV-radiation doses. This model (HMC uses modelled UV-radiation under clear sky conditions, a cloud modification factor, both with hourly resolution, and a monthly correction factor. A good agreement between modelled and measured values of erythemally effective irradiance was found at both stations. In relation to the reference period 1976–1985 an increase in erythemal UV-irradiance in Vienna of 11 percent is visible in the period 1986–1995 and an increase of 17 percent in the period 1996–2005 can be seen. At Hoher Sonnblick an increase of 2 percent has been calculated for the yearly averages in erythemal UV for the period 1986–1995 and an increase of 9 percent for the period 1996–2005 in comparison to the reference period. For the different seasons the strongest increase in erythemal UV radiation has been found for winter and spring season at both stations.

  16. On the Frontier: Some Observations of Surface Tension Phenomena from the International Space Station

    Science.gov (United States)

    Pettit, Don

    2016-11-01

    Frontiers are interesting places; they offer the possibility to make observations outside our normal range of experience. The International Space Station is such a frontier offering a local reduction in acceleration force by nearly a factor of a million thus allowing the observation of subtle phenomena that are typically masked on Earth. In this presentation we show a variety of unusually large length scale fluid interfacial phenomena dominated by electro-hydrodynamics, Marangoni convection, and non-Newtonian fluid mechanics. The experimental results presented are largely performed during weekends and other brief time-off periods allotted to the astronaut crew on the ISS.

  17. Empirical Requirements Analysis for Mars Surface Operations Using the Flashline Mars Arctic Research Station

    Science.gov (United States)

    Clancey, William J.; Lee, Pascal; Sierhuis, Maarten; Norvig, Peter (Technical Monitor)

    2001-01-01

    Living and working on Mars will require model-based computer systems for maintaining and controlling complex life support, communication, transportation, and power systems. This technology must work properly on the first three-year mission, augmenting human autonomy, without adding-yet more complexity to be diagnosed and repaired. One design method is to work with scientists in analog (mars-like) setting to understand how they prefer to work, what constrains will be imposed by the Mars environment, and how to ameliorate difficulties. We describe how we are using empirical requirements analysis to prototype model-based tools at a research station in the High Canadian Arctic.

  18. Beagle Rupes and Rembrandt scarp: a comparison on Mercury surface

    Science.gov (United States)

    Ferrari, S.; Massironi, M.; Rothery, D. A.; Cremonese, G.

    2011-10-01

    Areas of crustal convergence and shortening on Earth, Mars and Venus are often characterized by structural domains where thrust faults are associated with strike-slip systems [1]. In the case of Mercury most structures maintain a wide elongated frontal scarp and only few of them show kinematic indicators of lateral slip. The comparison between two Mercurian linked fault systems like Beagle Rupes [2] [3] and Rembrandt scarp [4] could aid understanding of whether diverse hermean strike-slip structures are influenced by geological context such as surface heterogeneity and crustal layering or have different deformational history.

  19. Comparison of different lateral acceleration autopilots for a surface-to-surface missile

    Directory of Open Access Journals (Sweden)

    Danilo V. Ćuk

    2011-07-01

    Full Text Available This paper presents a comparison of three lateral acceleration autopilots for a surface-to-surface missile: three-loop conventional acceleration autopilot, and gamma-dot and three-loop acceleration autopilot based upon the inverse-dynamic control. The surface-to-surface missile motion is described by nonlinear differential equations whose parameters change rapidly over a very wide range due to variable velocity and altitude. The requirement for the accurate controlling of the missile in such an environment represents a challenge for the autopilot designer. The brief review of the calculation of the autopilot gains is given using the concept of the 'point' stability for the linear time-varying system with 'frozen' dynamic coefficients. The method of the inverse-dynamic control is presented in the next section for two types of the autopilots: gamma-dot and acceleration autopilot. Both of them require the design of the estimators for the variables used as inputs to the control law. Finally, six-degree-of-freedom simulation results of the missile response to the demanded command on the typical ballistic trajectory are presented. The comparison of three autopilots considers the steady state errors and the sensitivity of the response to the highly variable environment. It was shown that the inverse-dynamic control can be very effective in the controlling of the surface-to-surface missile.

  20. Comparison of surface and hydrogel-based protein microchips.

    Science.gov (United States)

    Zubtsov, D A; Savvateeva, E N; Rubina, A Yu; Pan'kov, S V; Konovalova, E V; Moiseeva, O V; Chechetkin, V R; Zasedatelev, A S

    2007-09-15

    Protein microchips are designed for high-throughput evaluation of the concentrations and activities of various proteins. The rapid advance in microchip technology and a wide variety of existing techniques pose the problem of unified approach to the assessment and comparison of different platforms. Here we compare the characteristics of protein microchips developed for quantitative immunoassay with those of antibodies immobilized on glass surfaces and in hemispherical gel pads. Spotting concentrations of antibodies used for manufacturing of microchips of both types and concentrations of antigen in analyte solution were identical. We compared the efficiency of antibody immobilization, the intensity of fluorescence signals for both direct and sandwich-type immunoassays, and the reaction-diffusion kinetics of the formation of antibody-antigen complexes for surface and gel-based microchips. Our results demonstrate higher capacity and sensitivity for the hydrogel-based protein microchips, while fluorescence saturation kinetics for the two types of microarrays was comparable.

  1. Trends in surface-water quality at selected National Stream Quality Accounting Network (NASQAN) stations, in Michigan

    Science.gov (United States)

    Syed, Atiq U.; Fogarty, Lisa R.

    2005-01-01

    -treatment processes, and effective regulations. Phosphorus data for most of the study stations could not be analyzed because of the data limitations for trend tests. The only station with a significant negative trend in total phosphorus concentration is the Clinton River at Mount Clemens. However, scatter-plot analyses of phosphorus data indicate decreasing concentrations with time for most of the study stations. Positive trends in concentration of nitrogen compounds were detected at the Kalamazoo River near Saugatuck and Muskegon River near Bridgeton. Positive trends in both fecal coliform and total fecal coliform were detected at the Tahquamenon River near Paradise. Various different point and nonpoint sources could produce such positive trends, but most commonly the increase in concentrations of nitrogen compounds and fecal coliform bacteria are associated with agricultural practices and sewage-plant discharges. The constituent with the most numerous and geographically widespread significant trend is pH. The pH levels increased at six out of nine stations on all the major rivers in Michigan, with no negative trend at any station. The cause of pH increase is difficult to determine, as it could be related to a combination of anthropogenic activities and natural processes occurring simultaneously in the environment. Trends in concentration of major ions, such as calcium, sodium, magnesium, sulfate, fluoride, chloride, and potassium, were detected at eight out of nine stations. A negative trend was detected only in sulfate and fluoride concentrations; a positive trend was detected only in calcium concentration. The major ions with the most widespread significant trends are sodium and chloride; three positive and two negative trends were detected for sodium, and three negative and two positive trends were detected for chloride. The negative trends in chloride concentrations outnumbered the positive trends. This result indicates a slight improvement in surface-water quality because

  2. Near-Surface Attenuation and Velocity Structures in Taiwan from Wellhead and Borehole Recordings Comparisons

    National Research Council Canada - National Science Library

    Wang, Yu-Ju; Ma, Kuo-Fong; Wu, Shao-Kai; Hsu, Hsuan-Jui; Hsiao, Wen-Chi

    2016-01-01

    By analyzing the data from 28 seismic borehole stations deployed by the Central Weather Bureau Seismic Network throughout Taiwan from 2007 to 2014, we estimated the near-surface velocity (Vp and Vs) and attenuation (Qp and Qs...

  3. Passive seismic experiment - A summary of current status. [Apollo-initiated lunar surface station data

    Science.gov (United States)

    Latham, G. V.; Dorman, H. J.; Horvath, P.; Ibrahim, A. K.; Koyama, J.; Nakamura, Y.

    1978-01-01

    The data set obtained from the four-station Apollo seismic network including signals from approximately 11,800 events, is surveyed. Some refinement of the lunar model will result, but its gross features remain the same. Attention is given to the question of a small, molten lunar core, the answer to which remains dependent on analysis of signals from a far side impact. Seventy three sources of repeating, deep moonquakes have been identified, thirty nine of which have been accurately located. Concentrated at depths from 800 to 1000 km, the periodicities of these events have led to the hypothesis that they are generated by tidal stresses. Lunar seismic data has also indicated that the meteoroid population is ten times lower than originally determined from earth based observations. Lunar seismic activity is much lower and mountainous masses show no sign of sinking, in contrast to earth, as a result of the lunar crust being four times thicker. While much work remains to be done, significant correlation between terrestrial and lunar observations can be seen.

  4. Meteorological observations on Martian surface : met-packages of Mars-96 Small Stations and Penetrators

    Science.gov (United States)

    Harri, A.-M.; Linkin, V.; Polkko, J.; Marov, M.; Pommereau, J.-P.; Lipatov, A.; Siili, T.; Manuilov, K.; Lebedev, V.; Lehto, A.; Pellinen, R.; Pirjola, R.; Carpentier, T.; Malique, C.; Makarov, V.; Khloustova, L.; Esposito, L.; Maki, J.; Lawrence, G.; Lystsev, V.

    1998-02-01

    The scientific objectives of a meterological experiment on the Martian surface are defined, and the meteorological equipment of the landing elements of the Mars-96 mission are described with emphasis on the applicability for re-use in forthcoming Mars missions. The general strategy for atmospheric surface observations is discussed. Meteorological surface observations are of utmost value in studying the Martian atmosphere. The climatological cycles and atmospheric circulations, as well as the boundary layer phenomena can be understood thoroughly only, if the contribution of in situ surface measurements are amalgamated with the remote observations. The Mars-96 mission had an ambitious goal of deploying four versatile payloads at four Northern hemispheric sites. The observations of pressure, temperature, wind, atmospheric optical thickness and humidity, as well as pressure and temperature measurements during the atmospheric descent were included in the meteorology experiment. Even though the Mars-96 mission was unsuccessful, the objectives and implementation of the meteorology experiment are applicable to any forthcoming landing mission to Mars. This applies both to a mission having a number of observation sites spread all over the surface of Mars, and to a single lander or rover. The main operational objective of this meteorological experiment is to provide a regular time series of the meteorological parameters with accelerated measurement campaigns during dawn and dusk. Such a data set would substantially improve our understanding of the atmospheric structure, dynamics, climatological cycles, and the atmosphere-surface interactions. The implementation of the meteorology instrument features advanced sensor technology and flexible system design. The application on the Mars-96 landing elements was, however, severely constrained by the limited power supply. The usefulness of the system can be substantially enhanced by modest additional resources and with few or no

  5. A comparison of Methane data products from Chemistry Transport Models, SCIAMACHY and a network of FTIR stations

    Science.gov (United States)

    Dils, Bart; de Mazière, Martine; Vigouroux, Corinne

    2010-05-01

    Since its launch in 2002, the SCIAMACHY instrument on board ENVISAT has provided information on a large array of species affecting our environment. Methane, a species for which the retrieval algorithm development is still ongoing, is believed to be an important greenhouse gas. Thus, to effectively study the impact of CH4 on climate, information on its sources and sinks needs to be improved. To this end Eulerian Chemistry Transport models coupled with emission data are often compared with the available satellite data. However, since both model-emission databases and satellite data are still very much under development, it is very useful to compare both with independent third party data. In the framework of the EU project HYMN, the methane field as simulated by several Eulerian Chemistry Transport Models has been compared with data from a quasi-global network of groundbased Fourier Tranform Infrared (FTIR) spectrometers of NDACC. The FTIR data have been harmonized across the network in order to eliminate any station to station biases resulting from different retrieval parameter settings such as the choice of the retrieval spectral microwindows and the a priori profile selection. The models in question are TM4 developed at the Royal Netherlands Meteorological Institute (KNMI), LMDz-INCA (Laboratoire des Sciences du Climat et de l'Environnement (LSCE)) and CTM2 from the University of Oslo. The impact of several emission inventories on the modeled atmospheric CH4 distribution will be assessed. We will also discuss the inter-comparison of the latest IMAP-DOAS and WFM-DOAS CH4 SCHIAMACHY satellite products with said FTIR and model datasets, focusing on the seasonal cycle of methane.

  6. Predictions of U.K. regulated power station contributions to regional air pollution and deposition: a model comparison exercise.

    Science.gov (United States)

    Chemel, Charles; Sokhi, Ranjeet S; Dore, Anthony J; Sutton, Paul; Vincent, Keith J; Griffiths, Stephen J; Hayman, Garry D; Wright, Raymond D; Baggaley, Matthew; Hallsworth, Stephen; Prain, H Douglas; Fisher, Bernard E A

    2011-11-01

    Contributions of the emissions from a U.K. regulated fossil-fuel power station to regional air pollution and deposition are estimated using four air quality modeling systems for the year 2003. The modeling systems vary in complexity and emphasis in the way they treat atmospheric and chemical processes, and include the Community Multiscale Air Quality (CMAQ) modeling system in its versions 4.6 and 4.7, a nested modeling system that combines long- and short-range impacts (referred to as TRACK-ADMS [Trajectory Model with Atmospheric Chemical Kinetics-Atmospheric Dispersion Modelling System]), and the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model. An evaluation of the baseline calculations against U.K. monitoring network data is performed. The CMAQ modeling system version 4.6 data set is selected as the reference data set for the model footprint comparison. The annual mean air concentration and total deposition footprints are summarized for each modeling system. The footprints of the power station emissions can account for a significant fraction of the local impacts for some species (e.g., more than 50% for SO2 air concentration and non-sea-salt sulfur deposition close to the source) for 2003. The spatial correlation and the coefficient of variation of the root mean square error (CVRMSE) are calculated between each model footprint and that calculated by the CMAQ modeling system version 4.6. The correlation coefficient quantifies model agreement in terms of spatial patterns, and the CVRMSE measures the magnitude of the difference between model footprints. Possible reasons for the differences between model results are discussed. Finally, implications and recommendations for the regulatory assessment of the impact of major industrial sources using regional air quality modeling systems are discussed in the light of results from this case study.

  7. An Instrument for Measuring the Near-Surface PlasmaTemperature and Concentration, and the Surface Charging of the International Space Station

    Science.gov (United States)

    Kirov, B.

    2010-12-01

    The Langmuir probe is one of the classical instruments for plasma diagnostics [1] and among the first space-borne instruments. Langmuir probes have been successfully used aboard a number of rockets and satellites for in situ measurements of thermal plasma parameters in the terrestrial ionosphere [2], at other planets [3] and comets [4], and recently it is an indispensable instrument for measuring the satellite surface potential. In the present paper we discuss some theoretical and practical aspects of the application of the Langmuir probe for ionospheric measurements. We show that the spherical probe cannot be used for measurements in the ionosphere, and for the cylindrical probe the experimental Volt-Ampere curves are not described by the formula for an infinite cylinder. A formula is proposed for processing of this region. We demonstrate that in the case of two prevailing ions, their concentration can be found from the ion saturation region. Finally, we describe the two Langmuir probes designed and manufactured in Bulgaria, a part of the Plasma Wave Complex PWC (Obstanovka experiment) aboard the Russian segment of the International Space Station, whose goal is to monitor the surface charging and the noises and disturbances in the surrounding plasma induced by the station and by the experiments conducted aboard it.

  8. Layering of surface snow and firn at Kohnen Station, Antarctica: Noise or seasonal signal?

    Science.gov (United States)

    Laepple, Thomas; Hörhold, Maria; Münch, Thomas; Freitag, Johannes; Wegner, Anna; Kipfstuhl, Sepp

    2016-10-01

    The density of firn is an important property for monitoring and modeling the ice sheets as well as to model the pore close-off and thus to interpret ice core-based greenhouse gas records. One feature, which is still in debate, is the potential existence of an annual cycle of firn density in low-accumulation regions. Several studies describe or assume seasonally successive density layers, horizontally evenly distributed, as seen in radar data. On the other hand, high-resolution density measurements on firn cores in Antarctica and Greenland show no clear seasonal cycle in the top few meters. A major caveat of most existing snow-pit and firn-core-based studies is that they represent one vertical profile from a laterally heterogeneous density field. To overcome this, we created an extensive data set of horizontal and vertical density data at Kohnen Station, Dronning Maud Land, on the East Antarctic Plateau. We drilled and analyzed three 90 m long firn cores as well as 143 one-meter-long vertical profiles from two elongated snow trenches to obtain a two-dimensional view of the density variations. The analysis of the 45 m wide and 1 m deep density fields reveals a seasonal cycle in density. However, the seasonality is overprinted by strong stratigraphic noise, making it invisible when analyzing single firn cores. Our density data set extends the view from the local ice core perspective to a hundred meter scale and thus supports linking spatially integrating methods such as radar and seismic studies to ice and firn cores.

  9. Contaminations of inner surface of magnesium fluoride windows in the `Expose-R' experiment on the International Space Station

    Science.gov (United States)

    Skurat, V. E.

    2017-10-01

    A series of experiments was carried out previously on board of the International Space Station in `EXPOSE-R', a multi-user expose facility, provided by European Space Agency attached to the external surface of the Russian Segment. In one experiment, spores of microorganisms and species of higher plant seeds, in heat-sealed polymer bags were irradiated by solar radiation passed through MgF2 windows in a high space vacuum. After sample exposure, it was found that in many cases the inner surfaces of windows were contaminated. Analysis of the contamination revealed the presence of chemical groups CH2, CH3, NH, OH, C═O, Si-CH3 (Demets et al. in 2015). Their presence in deposits was explained by photofixation of gaseous precursors - some of the vapours of glues and additives in polymeric materials in the core facility of `Expose-R'. Carbon-, oxygen- and silicon-containing groups may be deposited from outer intrinsic atmosphere. This atmosphere is connected with sample compartments and core facility. However, the presence of NH groups on inner surfaces of windows was not expected. This paper shows that the process responsible for carbon-, nitrogen- and oxygen-containing group formation can be a photopolymerization of caprolactam, which is released from the outer Nylon 6 layer of polymer bags under Solar vacuum ultraviolet radiation.

  10. Comparison of total ozone and erythemal UV data from OMI with ground-based measurements at Rome station

    Directory of Open Access Journals (Sweden)

    I. Ialongo

    2008-02-01

    Full Text Available Ground-based total ozone and surface UV irradiance measurements have been collected since 1992 using Brewer spectrophotometer and Erythemal Dose Rates (EDRs have been determined by a broad-band radiometer (model YES UVB-1 operational since 2000 at Rome station. The methodology to retrieve the EDR and the Erythemal Daily Dose (EDD from the radiometer observations is described. Ground-based measurements were compared with satellite-derived total ozone and UV data from the Ozone Monitoring Instrument (OMI. OMI, onboard the NASA EOS Aura spacecraft, is a nadir viewing spectrometer that provides total ozone and surface UV retrievals. The results of the validation exercise showed satisfactory agreement between OMI and Brewer total ozone data, for both OMI-TOMS and OMI-DOAS ozone alghorithms (biases of −1.8% and −0.7%, respectively. Regarding UV data, OMI data overestimate ground-based erythemally weighted data retrieved from both Brewer and YES Radiometer (biases about 20%, probably because of the effect of absorbing aerosols in an urban site such as Rome.

  11. Comparisons of venus surface compositions with terrestrial ocean floor rocks

    Energy Technology Data Exchange (ETDEWEB)

    Garvin, J.B.; Bryan, W.B.

    1987-10-01

    Statistical comparison of Venera and Vega lander x-ray fluorescence spectrometer measurements of the composition of the Venus surface with an extensive database of compositional data for terrestrial ocean floor rocks indicates that the Venera 14 data matches certain tholeiitic basalts from the Kane Fracture Zone (KFZ) in the Mid-Atlantic Ridge (22-25/sup 0/N) at high confidence levels. The tholeiites most similar to the Venera measurements are very primitive, low-calcium, high-alumina pillow basalts depleted in clinopyroxene, and are relatively unique to certain fracture zones in oceanic regions. If the Venera 14 analogy is valid, the implication is that certain Venus basaltic magmas have lost clinopyroxene at relatively high pressures by fractionation, perhaps within a deep source region. Comparisons of Venera 13 and Vega 2 data with oceanic rocks yield poorer matches. Venera 13 matches Loihi seamount alkali basalts, as well as potassic mafic rocks from oceanic island such as Tristan de Cunha. The best analogy to Vega 2 may be altered gabbros or basic lavas from terrestrial basic intrusions such as the Troodos ophiolite. The close similarity of a representative sample of Venera 14 material with distinctive ocean floor tholeiitic basalts suggests that deep magma storage regions exist on Venus, and that derivation of both tholeiitic and alkalic magmas from a single primitive parent may be an important process on Venus.

  12. Comparison of durability requirements of new IEEE, CSA and IEC standards for metal-oxide station arrester

    Energy Technology Data Exchange (ETDEWEB)

    Lat, M.V.; Kirkby, P.; Ringler, K.; Kortschinski, J.; Erven, C. [Ontario Hydro Technologies, Toronto, ON (Canada)

    1998-04-01

    Three standards exist for metal-oxide station class surge arresters. These are the IEEE, CSA and IEC standards. The apparent incompatibilities of the standards make the task of arrester specification by utility engineers difficult. This study was conducted to analyze and compare the severity of the durability requirements of the the three standards under different service conditions. The comparison was conducted on the basis of the maximum calculated temperature rise of the valve elements. A validated electrothermal arrester modeling program was used for the analysis. Six different arrester designs, representing all IEC surge arrester line discharge classifications were used in the study. It was concluded that the electrothermal durability requirements of all three standards were very similar. The most critical test procedure, the 2-pulse transmission line discharge test, is virtually identical in all three standards in preheating the test sample to 60 degrees C and applying two rectangular current pulses. The major difference between the standards was in defining the magnitude of the current pulse and the energy it delivers into the test sample. 16 refs., 45 tabs., 77 figs., 3 appendices.

  13. Measurements of the linear energy transfer spectra on the Mir orbital station and comparison with radiation transport models

    Science.gov (United States)

    Badhwar, G. D.; Konradi, A.; Atwell, W.; Golightly, M. J.; Cucinotta, F. A.; Wilson, J. W.; Petrov, V. M.; Tchernykh, I. V.; Shurshakov, V. A.; Lobakov, A. P.

    1996-01-01

    A tissue equivalent proportional counter designed to measure the linear energy transfer spectra (LET) in the range 0.2-1250 keV/micrometer was flown in the Kvant module on the Mir orbital station during September 1994. The spacecraft was in a 51.65 degrees inclination, elliptical (390 x 402 km) orbit. This is nearly the lower limit of its flight altitude. The total absorbed dose rate measured was 411.3 +/- 4.41 microGy/day with an average quality factor of 2.44. The galactic cosmic radiation (GCR) dose rate was 133.6 microGy/day with a quality factor of 3.35. The trapped radiation belt dose rate was 277.7 microGy/day with an average quality factor of 1.94. The peak rate through the South Atlantic Anomaly was approximately 12 microGy/min and nearly constant from one pass to another. A detailed comparison of the measured LET spectra has been made with radiation transport models. The GCR results are in good agreement with model calculations; however, this is not the case for radiation belt particles and again points to the need for improving the AP8 omni-directional trapped proton models.

  14. Comparisons Between Model Predictions and Spectral Measurements of Charged and Neutral Particles on the Martian Surface

    Science.gov (United States)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F.; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; hide

    2014-01-01

    Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Radiation Assessment Detector (RAD) on the Curiosity rover since August 2012. RAD is a particle detector that measures the energy spectrum of charged particles (10 to approx. 200 MeV/u) and high energy neutrons (approx 8 to 200 MeV). The data obtained on the surface of Mars for 300 sols are compared to the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used. For describing the daily column depth of atmosphere, daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station (REMS) are implemented into transport calculations. Particle flux at RAD after traversing varying depths of atmosphere depends on the slant angles, and the model accounts for shielding of the RAD "E" dosimetry detector by the rest of the instrument. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and suggest that future radiation environments on Mars can be predicted accurately. These contributions lend support to the understanding of radiation health risks to astronauts for the planning of various mission scenarios

  15. Comparison of antibiotic resistance, biofilm formation and conjugative transfer of Staphylococcus and Enterococcus isolates from International Space Station and Antarctic Research Station Concordia.

    Science.gov (United States)

    Schiwon, Katarzyna; Arends, Karsten; Rogowski, Katja Marie; Fürch, Svea; Prescha, Katrin; Sakinc, Türkan; Van Houdt, Rob; Werner, Guido; Grohmann, Elisabeth

    2013-04-01

    The International Space Station (ISS) and the Antarctic Research Station Concordia are confined and isolated habitats in extreme and hostile environments. The human and habitat microflora can alter due to the special environmental conditions resulting in microbial contamination and health risk for the crew. In this study, 29 isolates from the ISS and 55 from the Antarctic Research Station Concordia belonging to the genera Staphylococcus and Enterococcus were investigated. Resistance to one or more antibiotics was detected in 75.8 % of the ISS and in 43.6 % of the Concordia strains. The corresponding resistance genes were identified by polymerase chain reaction in 86 % of the resistant ISS strains and in 18.2 % of the resistant Concordia strains. Plasmids are present in 86.2 % of the ISS and in 78.2 % of the Concordia strains. Eight Enterococcus faecalis strains (ISS) harbor plasmids of about 130 kb. Relaxase and/or transfer genes encoded on plasmids from gram-positive bacteria like pIP501, pRE25, pSK41, pGO1 and pT181 were detected in 86.2 % of the ISS and in 52.7 % of the Concordia strains. Most pSK41-homologous transfer genes were detected in ISS isolates belonging to coagulase-negative staphylococci. We demonstrated through mating experiments that Staphylococcus haemolyticus F2 (ISS) and the Concordia strain Staphylococcus hominis subsp. hominis G2 can transfer resistance genes to E. faecalis and Staphylococcus aureus, respectively. Biofilm formation was observed in 83 % of the ISS and in 92.7 % of the Concordia strains. In conclusion, the ISS isolates were shown to encode more resistance genes and possess a higher gene transfer capacity due to the presence of three vir signature genes, virB1, virB4 and virD4 than the Concordia isolates.

  16. Comparison of MELCOR modeling techniques and effects of vessel water injection on a low-pressure, short-term, station blackout at the Grand Gulf Nuclear Station

    Energy Technology Data Exchange (ETDEWEB)

    Carbajo, J.J.

    1995-06-01

    A fully qualified, best-estimate MELCOR deck has been prepared for the Grand Gulf Nuclear Station and has been run using MELCOR 1.8.3 (1.8 PN) for a low-pressure, short-term, station blackout severe accident. The same severe accident sequence has been run with the same MELCOR version for the same plant using the deck prepared during the NUREG-1150 study. A third run was also completed with the best-estimate deck but without the Lower Plenum Debris Bed (BH) Package to model the lower plenum. The results from the three runs have been compared, and substantial differences have been found. The timing of important events is shorter, and the calculated source terms are in most cases larger for the NUREG-1150 deck results. However, some of the source terms calculated by the NUREG-1150 deck are not conservative when compared to the best-estimate deck results. These results identified some deficiencies in the NUREG-1150 model of the Grand Gulf Nuclear Station. Injection recovery sequences have also been simulated by injecting water into the vessel after core relocation started. This marks the first use of the new BH Package of MELCOR to investigate the effects of water addition to a lower plenum debris bed. The calculated results indicate that vessel failure can be prevented by injecting water at a sufficiently early stage. No pressure spikes in the vessel were predicted during the water injection. The MELCOR code has proven to be a useful tool for severe accident management strategies.

  17. SUPPLEMENTARY COMPARISON - EUROMET.L-S11 comparison on surface texture

    DEFF Research Database (Denmark)

    Koenders, L.; Andreasen, Jan Lasson; De Chiffre, Leonardo

    2004-01-01

    of those used are traced back to SI by national metrology institutes (NMi), which should participate in international comparison to proof the validation of measurement results. Sixteen NMi from the EUROMET region carried out measurements on standards between May 2001 and March 2003. The set of standards......The measurement of roughness of technical surfaces is important in research and for industry. There are a lot of 2D roughness parameters that are defined and standardized by ISO. Calibration standards can be used to calibrate the instruments and ensure traceability to the SI unit of length. Most...... used complied with ISO 5436-1 and consisted of one depth-setting standard of type A, three calibration standards of type C, three standards of type D1 and one standard of type D2. The participants aimed to measure 50 surface roughness parameters. These included the most interesting parameters...

  18. Comparison of elevation and remote sensing derived products as auxiliary data for climate surface interpolation

    Science.gov (United States)

    Alvarez, Otto; Guo, Qinghua; Klinger, Robert C.; Li, Wenkai; Doherty, Paul

    2013-01-01

    Climate models may be limited in their inferential use if they cannot be locally validated or do not account for spatial uncertainty. Much of the focus has gone into determining which interpolation method is best suited for creating gridded climate surfaces, which often a covariate such as elevation (Digital Elevation Model, DEM) is used to improve the interpolation accuracy. One key area where little research has addressed is in determining which covariate best improves the accuracy in the interpolation. In this study, a comprehensive evaluation was carried out in determining which covariates were most suitable for interpolating climatic variables (e.g. precipitation, mean temperature, minimum temperature, and maximum temperature). We compiled data for each climate variable from 1950 to 1999 from approximately 500 weather stations across the Western United States (32° to 49° latitude and −124.7° to −112.9° longitude). In addition, we examined the uncertainty of the interpolated climate surface. Specifically, Thin Plate Spline (TPS) was used as the interpolation method since it is one of the most popular interpolation techniques to generate climate surfaces. We considered several covariates, including DEM, slope, distance to coast (Euclidean distance), aspect, solar potential, radar, and two Normalized Difference Vegetation Index (NDVI) products derived from Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS). A tenfold cross-validation was applied to determine the uncertainty of the interpolation based on each covariate. In general, the leading covariate for precipitation was radar, while DEM was the leading covariate for maximum, mean, and minimum temperatures. A comparison to other products such as PRISM and WorldClim showed strong agreement across large geographic areas but climate surfaces generated in this study (ClimSurf) had greater variability at high elevation regions, such as in the Sierra

  19. A comparison of TEC predicted by IRI-2012 with that measured at three different stations in low latitude Indian region for the years (2010-2012)

    Science.gov (United States)

    Karia, S. P.; Patel, N. C.; Pathak, K. N.

    2017-07-01

    The present study reports the comparison of GPS measured Total Electron Content (TEC) with that predicted by the latest IRI-2012 model at three different stations located within the Equatorial Ionization Anomaly region (EIA) in the Indian sector. The data used for the study are retrieved from three different stations, namely, Surat (geographic latitude 21.16°N, geographic longitude 72.78°E; geomagnetic latitude 12.90°N), Hyderabad (geographic latitude 17.25°N, geographic longitude 78.30°E; geomagnetic latitude 8.65°N) and Bangalore (geographic latitude 13.02°N, geographic longitude 77.57°E; geomagnetic latitude 4.58°N). The period of comparison is three years for rising solar activity from 2010 to 2012. Here it is to note that both Hyderabad and Bangalore are IGS station with the station code (HYDE and IISC respectively). The results for the comparison of seasonal variation shows a good agreement between the measured and modeled TEC for all seasons with deviation of (±15 TECU) for all three years at Surat and Bangalore and with a deviation of (±25 TECU) at Hyderabad. Both topside options NeQuick and IRI01-Corr derived nearly equal TEC at all three stations. It is observed that the GPS TEC data shows the EIA crest at (23.5°N) where as the IRI TEC predicts the EIA crest at (19.7°N) on an average for all the years 2010-2012.

  20. Kalman filter physical retrieval of surface emissivity and temperature from SEVIRI infrared channels: a validation and inter-comparison study

    Directory of Open Access Journals (Sweden)

    G. Masiello

    2015-04-01

    Full Text Available A Kalman filter based approach for the physical retrieval of surface temperature and emissivity from SEVIRI (Spinning Enhanced Visible and Infrared Imager infrared observations has been developed and validated against in situ and satellite observations. Validation for land has been provided based on in situ observations from the two permanent stations Evora and Gobabeb operated by Karlsruhe Institute of Technology (KIT within the framework of EUMETSAT's Satellite Application Facility on Land Surface Analysis (LSA-SAF. Sea surface retrievals have been intercompared on a broad spatial scale with equivalent satellite products (MODIS or Moderate Resolution Imaging Spectroradiometer and AVHRR or Advanced Very High Resolution Radiometer and ECMWF (European Centre for Medium Range Weather Forecasts analyses. Results show that for surface temperature the algorithm yields an accuracy of ≈ ± 1.5 °C in case of land and ≈ ± 1.0 °C in case of sea surface. Comparisons with polar satellite instruments over the sea surface show nearly zero temperature bias. Over the land surface the retrieved emissivity follows the seasonal vegetation cycle and allows to identify desert sand regions because of strong reststrahlen bands of Quartz in the SEVIRI channel at 8.7 μm. Considering the two validation stations, we have that emissivity retrieved in SEVIRI channel 10.8 μm over the gravel plains of the Namib desert is in excellent agreement with in situ observations. Over Evora, the seasonal variation of emissivity with vegetation is successfully retrieved and yields emissivity values for green and dry vegetation that are in good agreement with spectral library data. The algorithm has been applied to the SEVIRI full disk and emissivity maps on that global scale have been physically retrieved for the first time.

  1. Surface wave site characterization at 27 locations near Boston, Massachusetts, including 2 strong-motion stations

    Science.gov (United States)

    Thompson, Eric M.; Carkin, Bradley A.; Baise, Laurie G.; Kayen, Robert E.

    2014-01-01

    microzonation map based on generalized velocity profiles, where the amplifications were computed using Shake (Schnable and others, 1972), along with an assumed input ground motion. The velocities were constrained by only a few local measurements associated with the Central Artery/Tunnel project. The additional VS measurements presented in this report provide a number of benefits. First, these measurements provide improved spatial coverage. Second, the larger sample size provides better constraints on the mean and variance of the VS distribution for each layer, which may be paired with a three-dimensional (3D) model of the stratigraphy to generate one-dimensional (1D) profiles for use in a standard site-response analysis (for example, Britton, 2003). Third, the velocity profiles may also be used, along with a 3D model of the stratigraphy, as input into a 3D simulation of the ground motion to investigate the effects of basin-generated surface waves and the potential focusing of seismic waves.This report begins with a short review of the geology of the study area and the field methods that we used to estimate the velocity profiles. The raw data, processed data, and the interpreted VS profiles are given in appendix 1. Photographs and descriptions of the sites are provided in appendix 2.

  2. Meteorological effects of the solar eclipse of 20 March 2015: analysis of UK Met Office automatic weather station data and comparison with automatic weather station data from the Faroes and Iceland

    Science.gov (United States)

    Penman, John; Jónsson, Trausti; Bigg, Grant R.; Björnsson, Halldór; Sjúrðarson, Sølvi; Hansen, Mads A.; Cappelen, John; Bryant, Robert G.

    2016-01-01

    Here, we analyse high-frequency (1 min) surface air temperature, mean sea-level pressure (MSLP), wind speed and direction and cloud-cover data acquired during the solar eclipse of 20 March 2015 from 76 UK Met Office weather stations, and compare the results with those from 30 weather stations in the Faroe Islands and 148 stations in Iceland. There was a statistically significant mean UK temperature drop of 0.83±0.63°C, which occurred over 39 min on average, and the minimum temperature lagged the peak of the eclipse by about 10 min. For a subset of 14 (16) relatively clear (cloudy) stations, the mean temperature drop was 0.91±0.78 (0.31±0.40)°C but the mean temperature drops for relatively calm and windy stations were almost identical. Mean wind speed dropped significantly by 9% on average during the first half of the eclipse. There was no discernible effect of the eclipse on the wind-direction or MSLP time series, and therefore we can discount any localized eclipse cyclone effect over Britain during this event. Similar changes in air temperature and wind speed are observed for Iceland, where conditions were generally clearer, but here too there was no evidence of an eclipse cyclone; in the Faroes, there was a much more muted meteorological signature. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550769

  3. Meteorological effects of the solar eclipse of 20 March 2015: analysis of UK Met Office automatic weather station data and comparison with automatic weather station data from the Faroes and Iceland.

    Science.gov (United States)

    Hanna, Edward; Penman, John; Jónsson, Trausti; Bigg, Grant R; Björnsson, Halldór; Sjúrðarson, Sølvi; Hansen, Mads A; Cappelen, John; Bryant, Robert G

    2016-09-28

    Here, we analyse high-frequency (1 min) surface air temperature, mean sea-level pressure (MSLP), wind speed and direction and cloud-cover data acquired during the solar eclipse of 20 March 2015 from 76 UK Met Office weather stations, and compare the results with those from 30 weather stations in the Faroe Islands and 148 stations in Iceland. There was a statistically significant mean UK temperature drop of 0.83±0.63°C, which occurred over 39 min on average, and the minimum temperature lagged the peak of the eclipse by about 10 min. For a subset of 14 (16) relatively clear (cloudy) stations, the mean temperature drop was 0.91±0.78 (0.31±0.40)°C but the mean temperature drops for relatively calm and windy stations were almost identical. Mean wind speed dropped significantly by 9% on average during the first half of the eclipse. There was no discernible effect of the eclipse on the wind-direction or MSLP time series, and therefore we can discount any localized eclipse cyclone effect over Britain during this event. Similar changes in air temperature and wind speed are observed for Iceland, where conditions were generally clearer, but here too there was no evidence of an eclipse cyclone; in the Faroes, there was a much more muted meteorological signature.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'.

  4. Ice thickness, internal layers, and surface and subglacial topography in the vicinity of Chinese Antarctic Taishan station in Princess Elizabeth Land, East Antarctica

    Institute of Scientific and Technical Information of China (English)

    Tang Xue-Yuan; Guo Jing-Xue; Sun Bo; Wang Tian-Tian; Cui Xiang-Bin

    2016-01-01

    We present the results of two ground-based radio-echo-sounding (RES) and GPS surveys performed in the vicinity of new Chinese Taishan station, Princess Elizabeth Land, East Antarctica, obtained in two austral summers during CHINARE 21 (2004/2005) and CHINARE 29 (2012/2013). The radar surveys measured ice thickness and internal layers using 60- and 150-MHz radar systems, and GPS measurements showed smooth surface slopes around the station with altitudes of 2607–2636 m above sea level (a.s.l.). Radar profiles indicate an average ice thickness of 1900 m, with a maximum of 1949 m and a minimum of 1856 m, within a square area measuring approximately 2 km × 2 km in the vicinity of the station. The ice thickness beneath the station site is 1870 m. The subglacial landscape beneath the station is quiet sharp and ranges from 662 to 770 m a.s.l., revealing part of a mountainous topography. The ice volume in the grid is estimated to be 7.6 km3. Along a 60-MHz radar profi le with a length of 17.6 km at the region covering the station site, some disturbed internal layers are identifi ed and traced; the geometry of internal layers within the englacial stratigraphy may imply a complex depositional process in the area.

  5. Comparison of two split-window methods for retrieving land surface temperature from MODIS data

    Indian Academy of Sciences (India)

    Shaohua Zhao; Qiming Qin; Yonghui Yang; Yujiu Xiong; Guoyu Qiu

    2009-08-01

    Land surface temperature (LST) is a key parameter in environment and earth science study, especially for monitoring drought. The objective of this work is a comparison of two split-window methods: Mao method and Sobrino method, for retrieving LST using MODIS (Moderate-resolution Imaging Spectroradiometer) data in North China Plain. The results show that the max, min and mean errors of Mao method are 1.33K, 1.54K and 0.13K lower than the standard LST product respectively; while those of Sobrino method are 0.73K, 1.46K and 1.50K higher than the standard respectively. Validation of the two methods using LST product based on weather stations shows a good agreement between the standard and Sobrino method, with RMSE of 1.17K, whereas RMSE of Mao method is 1.85K. Finally, the study introduces the Sobmao method, which is based on Sobrino method but simplifies the estimation of atmospheric water vapour content using Mao method. The Sobmao method has almost the same accuracy with Sobrino method. With high accuracy and simplification of water vapour content estimation, the Sobmao method is recommendable in LST inversion for good application in Ningxia region, the northwest China, with mean error of 0.33K and the RMSE value of 0.91K.

  6. Quasi-periodic oscillations of aerosol backscatter profiles and surface meteorological parameters during winter nights over a tropical station

    Directory of Open Access Journals (Sweden)

    M. G. Manoj

    2011-03-01

    Full Text Available Atmospheric gravity waves, which are a manifestation of the fluctuations in buoyancy of the air parcels, are well known for their direct influence on concentration of atmospheric trace gases and aerosols, and also on oscillations of meteorological variables such as temperature, wind speed, visibility and so on. The present paper reports quasi-periodic oscillations in the lidar backscatter signal strength due to aerosol fluctuations in the nocturnal boundary layer, studied with a high space-time resolution polarimetric micro pulse lidar and concurrent meteorological parameters over a tropical station in India. The results of the spectral analysis of the data, archived on some typical clear-sky conditions during winter months of 2008 and 2009, exhibit a prominent periodicity of 20–40 min in lidar-observed aerosol variability and show close association with those observed in the near-surface temperature and wind at 5% statistical significance. Moreover, the lidar aerosol backscatter signal strength variations at different altitudes, which have been generated from the height-time series of the one-minute interval profiles at 2.4 m vertical resolution, indicate vertical propagation of these waves, exchanging energy between lower and higher height levels. Such oscillations are favoured by the stable atmospheric background condition and peculiar topography of the experimental site. Accurate representation of these buoyancy waves is essential in predicting the sporadic fluctuations of weather in the tropics.

  7. Investigation of surface ozone variability over the Antractic Plateau by observations at the "Concordia" WMO/GAW contributing station

    Science.gov (United States)

    Cristofanelli, Paolo; Udisti, Roberto; Busetto, Maurizio; Calzolari, Francescopiero; Putero, Davide; Lupi, Angelo; Mazzola, Mauro; Petkov, Boyan; Bonasoni, Paolo

    2017-04-01

    Tropospheric ozone (O3), is a greenhouse gas and a driver for atmosphere oxidative capacity. It has at least doubled since pre-industrial age but a comprehensive understanding of the global distribution and trends are difficult to achieve due to its reactivity. Measurements at Antarctic locations provide the opportunity to investigate O3 variability without direct anthropogenic influence providing information on its background variability. This work will focus on the investigation of the variability of surface tropospheric O3 over the eastern Antarctic Plateau. In particular, we will analyze seven years (2006 - 2013) of continuous observations at the WMO/GAW Contributing Station Concordia (75.10°S, 123.33°E, 3233m a.s.l. m) with the purpose of shading light on specific atmospheric processes that need to be accurately taken into account for interpreting O3 variability: (i) in-situ NOx emissions and subsequent photochemical O3 production during summer, (ii) long-range transport of air-masses enriched in O3 by photochemical production over the surface of Antarctic Plateau, (iii) long-range transport of air-masses depleted in O3 from coastal regions or open oceans. Moreover, even if their influence is expected to be limited, the possible influence of STE will be specifically investigated. To this aims, in-situ O3 variability will be analyzed as a function of 3D air-mass back-trajectories calculated by the HYSPLIT and FLEXTRA models. Co-variability with meteorological parameters and other atmospheric tracers (e.g. aerosol measurement as a function of key source and transport processes) will be also studied in order to provide a preliminary assessment of their impact on O3 variability. The STEFLUX (Stratosphere-to-Troposphere Exchange Flux) tool will be used to investigate the influence of stratosphere-to-troposphere transport on ozone variability over eastern Antarctic Plateau.

  8. Application of the nonlinear time series prediction method of genetic algorithm for forecasting surface wind of point station in the South China Sea with scatterometer observations

    Science.gov (United States)

    Zhong, Jian; Dong, Gang; Sun, Yimei; Zhang, Zhaoyang; Wu, Yuqin

    2016-11-01

    The present work reports the development of nonlinear time series prediction method of genetic algorithm (GA) with singular spectrum analysis (SSA) for forecasting the surface wind of a point station in the South China Sea (SCS) with scatterometer observations. Before the nonlinear technique GA is used for forecasting the time series of surface wind, the SSA is applied to reduce the noise. The surface wind speed and surface wind components from scatterometer observations at three locations in the SCS have been used to develop and test the technique. The predictions have been compared with persistence forecasts in terms of root mean square error. The predicted surface wind with GA and SSA made up to four days (longer for some point station) in advance have been found to be significantly superior to those made by persistence model. This method can serve as a cost-effective alternate prediction technique for forecasting surface wind of a point station in the SCS basin. Project supported by the National Natural Science Foundation of China (Grant Nos. 41230421 and 41605075) and the National Basic Research Program of China (Grant No. 2013CB430101).

  9. Interannual variability of surface heat fluxes in the Adriatic Sea in the period 1998-2001 and comparison with observations

    Energy Technology Data Exchange (ETDEWEB)

    Chiggiato, Jacopo [Servizio Idro Meteorologico, ARPA Emilia Romagna, Viale Silvani 6, I-40122 Bologna (Italy) and Universita degli Studi di Bologna, Dipartimento di Scienze della Terra, Piazza Porta San Donato 1, I-40126 Bologna (Italy)]. E-mail: jchiggiato@smr.arpa.emr.it; Zavatarelli, Marco [Universita di Bologna, Centro Interdipartimentale per la Ricerca sulle Scienze Ambientali, Via S. Alberto 163, I-47100 Ravenna (Italy); Castellari, Sergio [Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti 12, I-40128 Bologna (Italy); Deserti, Marco [Servizio Idro Meteorologico, ARPA Emilia Romagna, Viale Silvani 6, I-40122 Bologna (Italy)

    2005-12-15

    Surface heat fluxes of the Adriatic Sea are estimated for the period 1998-2001 through bulk formulae with the goal to assess the uncertainties related to their estimations and to describe their interannual variability. In addition a comparison to observations is conducted. We computed the components of the sea surface heat budget by using two different operational meteorological data sets as inputs: the ECMWF operational analysis and the regional limited area model LAMBO operational forecast. Both results are consistent with previous long-term climatology and short-term analyses present in the literature. In both cases we obtained that the Adriatic Sea loses 26 W/m{sup 2} on average, that is consistent with the assessments found in the literature. Then we conducted a comparison with observations of the radiative components of the heat budget collected on offshore platforms and one coastal station. In the case of shortwave radiation, results show a little overestimation on the annual basis. Values obtained in this case are 172 W/m{sup 2} when using ECMWF data and 169 W/m{sup 2} when using LAMBO data. The use of either Schiano's or Gilman's and Garrett's corrections help to get even closer values. More difficult is to assess the comparison in the case of longwave radiation, with relative errors of an order of 10-20%.

  10. Comparison of Products from ERA-40, NCEP-2, and CRU with Station Data for Summer Precipitation over China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Summer precipitation products from the 45-Year European Centre for Medium-Range Weather Forecast (ECMWF) Reanalysis (ERA-40), and NCEP-Department of Energy (DOE) Atmospheric Model Intercomparison Project (AMIP-Ⅱ) Reanalysis (NCEP-2), and Climatic Research Unit (CRU) TS 2.1dataset are compared with the corresponding observations over China in order to understand the quality and utility of the reanalysis datasets for the period 1979-2001. The results reveal that although the magnitude and location of the rainfall belts differ among the reanalysis, CRU, and station data over South and West China, the spatial distributions show good agreement over most areas of China. In comparison with the observations in most areas of China, CRU best matches the observed summer precipitation,while ERA-40 reports less precipitation and NCEP-2 reports more precipitation than the observations.With regard to the amplitude of the interannual variations, CRU is better than either of the reanalyses in representing the corresponding observations. The amplitude in NCEP-2 is stronger but that of ERA-40 is weaker than the observations in most study domains. NCEP-2 has a more obvious interannual variability than ERA-40 or CRU in most areas of East China. Through an Empirical orthogonal function (EOF)analysis, the main features of the rainfall belts produced by CRU agree better with the observations than with those produced by the reanalyses in the Yangtze-Huaihe River valley. In East of China, particularly in the Yangtze-Huaihe River valley, CRU can reveal the quasi-biennial oscillation of summer precipitation represented by the observations, but the signal of ERA-40 is comparatively weak and not very obvious,whereas that of NCEP-2 is also weak before 1990 but very strong after 1990. The results also suggest that the magnitude of the precipitation difference between ERA-40 and the observations is smaller than that between NCEP-2 and the observations, but the variations represented by NCEP-2

  11. MONITORING AND CONTROLLING ON SURFACE SETTLEMENT IN SAND AND GRAVEL STRATA CAUSED BY SUBWAY STATION CONSTRUCTION APPLYING PIPE-ROOF PRE-CONSTRUCTION METHOD (PPM

    Directory of Open Access Journals (Sweden)

    Xian Yang

    2017-07-01

    Full Text Available Pipe-roof Pre-construction Method (PPM is regarded as a safer method to construct underground space, especially suitable for the construction sites with dense surface buildings, underground pipelines and complicated geological conditions. Xinleyizhi Station of Shenyang Metro constructed by PPM. In order to ensure safety in construction, the whole construction process was closely monitored. In this paper, monitoring results of surface settlement in PPM is analyzed. According to the monitoring results, the most serious settlement occurred in pipes jacking, which was the first and the most crucial step in PPM. The settlement reasons in each step are discussed, and controlling methods of surface settlement in each step are elaborated. Through close monitoring and timely control, the construction of Xinleyizhi Station completed smoothly. Because of the obvious advantages of PPM, the method will be used more widely in construction of shallow buried excavation under complicated surrounding and geological conditions.

  12. Automated delineation and characterization of watersheds for more than 3,000 surface-water-quality monitoring stations active in 2010 in Texas

    Science.gov (United States)

    Archuleta, Christy-Ann M.; Gonzales, Sophia L.; Maltby, David R.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Texas Commission on Environmental Quality, developed computer scripts and applications to automate the delineation of watershed boundaries and compute watershed characteristics for more than 3,000 surface-water-quality monitoring stations in Texas that were active during 2010. Microsoft Visual Basic applications were developed using ArcGIS ArcObjects to format the source input data required to delineate watershed boundaries. Several automated scripts and tools were developed or used to calculate watershed characteristics using Python, Microsoft Visual Basic, and the RivEX tool. Automated methods were augmented by the use of manual methods, including those done using ArcMap software. Watershed boundaries delineated for the monitoring stations are limited to the extent of the Subbasin boundaries in the USGS Watershed Boundary Dataset, which may not include the total watershed boundary from the monitoring station to the headwaters.

  13. Study and optimization of boronization in Alcator C-Mod using the Surface Science Station (S{sup 3})

    Energy Technology Data Exchange (ETDEWEB)

    Ochoukov, Roman, E-mail: ochoukov@psfc.mit.edu [Plasma Science and Fusion Center MIT, NW17, 175 Albany Street, Cambridge, MA 02139 (United States); Whyte, Dennis; Lipschultz, Bruce; LaBombard, Brian [Plasma Science and Fusion Center MIT, NW17, 175 Albany Street, Cambridge, MA 02139 (United States); Gierse, Niels [Institute of Energy and Climate Research - Plasma Physics, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Juelich (Germany); Physikalisches Institut, Universitaet zu Koeln, D-50937 Cologne (Germany); Harrison, Soren [Fusion Research Technologies, 519 Somerville Avenue 243, Somerville, MA 02143 (United States)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Boron deposition profiles measured on Alcator C-Mod during boronization. Black-Right-Pointing-Pointer Boron deposition profile is consistent with ionic deposition. Black-Right-Pointing-Pointer Monte Carlo simulation of boron deposition agrees with experiment assuming warm ({approx}1-10 eV) boron{sup +1} ions. - Abstract: A Surface Science Station (S{sup 3}) on the Alcator C-Mod tokamak is used to study and optimize the location and rate of boron film deposition in situ during electron cyclotron (EC) discharge plasmas using 2.45 GHz radio-frequency (RF) heating and a mixture of helium and diborane (B{sub 2}D{sub 6}) gasses. The radial profile of boron deposition is measured with a pair of quartz microbalances (QMB) on S{sup 3}, the faces of which can be rotated 360 Degree-Sign including orientations parallel and perpendicular to the toroidal magnetic field B{sub T} {approx}0.1 T. The plasma electron density is measured with a Langmuir probe, also on S{sup 3} in the vicinity of the QMBs, and typical values are {approx}1 Multiplication-Sign 10{sup 16} m{sup -3}. A maximum boron deposition rate of 0.82 {mu}g/cm{sup 2}/min is obtained, which corresponds to 3.5 nm/min if the film density is that of solid boron. These deposition rates are sufficient for boron film applications between tokamak discharges. However the deposition does not peak at the EC resonance as previously assumed. Rather, deposition peaks near the upper hybrid (UH) resonance, {approx}5 cm outboard of the EC resonance. This has implications for RF absorption, with the RF waves being no longer damped on the electrons at the EC resonance. The previously inferred radial locations of critical erosion zones in Alcator C-Mod also need to be re-evaluated. The boron deposition profile versus major radius follows the ion flux/density profile, implying that the boron deposition is primarily ionic. The application of a vertical magnetic field (B{sub V} {approx}0.01 T) was

  14. The laser reference line method and its comparison to a total station in an ATLAS like configuration

    CERN Document Server

    Batusov, V; Lyablin, M; Gayde, J -Ch; Girolamo, B; Mergelkuhl, D; Nessi, M

    2014-01-01

    A new type of measuring system, the Laser Reference Line, is proposed as a metrological tool and can be used within limited space to ensure a precise installation along an axis on the ATLAS interaction point. A simplified ATLAS like beam pipe mock-up is used for this test. The coordinates of the beam pipe are measured three times using the new method and a Total Station. The measurements agree within the measurement error of the Total Station, which indicates that the precision of the laser reference line is suitable for this specific task in the ATLAS experiment.

  15. On the Comparison of the Global Surface Soil Moisture product and Land Surface Modeling

    Science.gov (United States)

    Delorme, B., Jr.; Ottlé, C.; Peylin, P.; Polcher, J.

    2016-12-01

    Thanks to its large spatio-temporal coverage, the new ESA CCI multi-instruments dataset offers a good opportunity to assess and improve land surface models parametrization. In this study, the ESA CCI surface soil moisture (SSM) combined product (v2.2) has been compared to the simulated top first layers of the ORCHIDEE LSM (the continental part of the IPSL earth system model), in order to evaluate its potential of improvements with data assimilation techniques. The ambition of the work was to develop a comprehensive comparison methodology by analyzing simultaneously the temporal and spatial structures of both datasets. We analyzed the SSM synoptic, seasonal, and inter-annual variations by decomposing the signals into fast and slow components. ORCHIDEE was shown to adequately reproduce the observed SSM dynamics in terms of temporal correlation. However, these correlation scores are supposed to be strongly influenced by SSM seasonal variability and the quality of the model input forcing. Autocorrelation and spectral analyses brought out disagreements in the temporal inertia of the upper soil moisture reservoirs. By linking our results to land cover maps, we found that ORCHIDEE is more dependent on rainfall events compared to the observations in regions with sparse vegetation cover. These diflerences might be due to a wrong partition of rainfall between soil evaporation, transpiration, runofl and drainage in ORCHIDEE. To refine this analysis, a single value decomposition (SVD) of the co-variability between rainfall provided by WFDEI and soil moisture was pursued over Central Europe and South Africa. It showed that spatio-temporal co-varying patterns between ORCHIDEE and rainfall and the ESA-CCI product and rainfall are in relatively good agreement. However, the leading SVD pattern, which exhibits a strong annual cycle and explains the same portion of covariance for both datasets, explains a much larger fraction of variance for ORCHIDEE than for the ESA-CCI product

  16. The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations

    Science.gov (United States)

    Steffensen Schmidt, Louise; Aðalgeirsdóttir, Guðfinna; Guðmundsson, Sverrir; Langen, Peter L.; Pálsson, Finnur; Mottram, Ruth; Gascoin, Simon; Björnsson, Helgi

    2017-07-01

    A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980-2014, is used to estimate the evolution of the glacier surface mass balance (SMB). This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs) from the period 2001-2014, as well as in situ SMB measurements from the period 1995-2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995-2014) shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981-2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes currently not accounted for in RCMs

  17. The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations

    Directory of Open Access Journals (Sweden)

    L. S. Schmidt

    2017-07-01

    Full Text Available A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980–2014, is used to estimate the evolution of the glacier surface mass balance (SMB. This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs from the period 2001–2014, as well as in situ SMB measurements from the period 1995–2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995–2014 shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981–2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes

  18. The use of vertical and horizontal surface displacements at EPOS GNSS stations in Greenland to study ice sheet mass balance

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas

    2014-01-01

    and present-day changes in ice mass. Superimposed on longer-term trends, an anomalous ‘pulse’ of uplift accumulated at many GNSS stations during an approximate six-month period in 2010 and 2012. This anomalous uplift is spatially correlated with the 2010 melting day anomaly (Bevis et al.,2012) and show...... present data from arctic GNSS stations included in the EPOS network. The arctic EPOS GNSS network consists of 16 continuous GPS stations spread across Greenland. This network is able to map the velocity fields associated with, plate motion, postglacial rebound and improve our understanding of tectonic...... processes and present-day ice mass changes in Greenland, allowing scientists to quickly detect and analyze any abrupt changes in the rate of ice loss in this region. Recent analyses of the EPOS-GNSS data and GNET data (Greenland GPS Network) show that the entire network is uplifting in response to past...

  19. Ground-based FTIR measurements of CO from the Jungfraujoch: characterisation and comparison with in situ surface and MOPITT data

    Directory of Open Access Journals (Sweden)

    B. Barret

    2003-01-01

    Full Text Available CO vertical profiles have been retrieved from solar absorption FTIR spectra recorded at the NDSC station of the Jungfraujoch (46.5º N, 8º E and 3580 m a.s.l. for the period from January 1997 to May 2001. The characterisation of these profiles has been established by an information content analysis and an estimation of the error budgets. A partial validation of the profiles has been performed through comparisons with correlative measurements. The average volume mixing ratios (vmr in the 3 km layer above the station have been compared with coincident surface measurements. The agreement between monthly means from both measurement techniques is very good, with a correlation coefficient of 0.87, and no significant bias observed. The FTIR total columns have also been compared to CO partial columns above 3580 m a.s.l. derived from the MOPITT (Measurement Of Pollution In The Troposphere instrument for the period March 2000 to May 2001. Relative to the FTIR columns, the MOPITT partial columns exhibit a positive bias of 8±8% for daytime and of 4±7% for nighttime measurements.

  20. Continuous atmospheric 222Rn concentration measurements to study surface-air exchange at the station of Gredos and Iruelas, in Central Spain

    Science.gov (United States)

    Grossi, Claudia; Morgui, Josep Anton; Àgueda, Alba; Batet, Oscar; Curcoll, Roger; Arias, Rosa; Arnold, Delia; Ealo, Marina; Nofuentes, Manel; Occhipinti, Paola; Sánchez-Garcíaa, Laura; Vargas, Arturo; Rodó, Xavier

    2013-04-01

    The Gredos and Iruelas station (GIC3) is part of the ClimaDat IC3 network (http://climadat.es/). This station is located in the Gredos Natural Park at a latitude of 40.22° N and a longitude of -5.14° E in the Spanish central plateau. The ClimaDat network is made by 8 stations distributed around Spain and it has been developed with the aim of studying climatic processes and the responses of impacted systems, at different time and space scales. Since November 2012, measurements of CO2, CH4, and of the natural radioactive gas 222Rn are continuously performed at GIC3 station at 20 m agl and at 1100 m asl . Maximum,minimum and average values of meteorological parameters, such as ambient air humidity and temperature, wind speed and direction are also measured at GIC3 station. Particularly, the concentration series of 222Rn measured at GIC3 station are extremely useful to evaluate the exchange of this noble radioactive gas between the soil surface and the lower troposphere in this area, under different weather situations and environmental conditions. The Gredos Natural Park is located in a granitic basement and this type of soil presents a high porosity and permeability. Furthermore, granitic materials have high activity levels of 228U. These factors enable large amount of radon to escape from the deeper soil, giving radon flux values of 90-100 Bq m-2 h-1 . These radon flux values are much higher than the average radon flux over the Earth, which is about 50 Bq m-2 h-1 (Szegvary et al, 2009). On the other hand, this geographical area is frequently affected by snow and rain events which drastically reduce the local radon exhalation. It is also influenced by winds coming from the Atlantic Ocean, which are poor in radon and strong, causing an important mixing. In addition, the cold nights' stability leads to an observed nocturnal radon accumulation. All the aforementioned conditions influence atmospheric radon concentrations measured at the GIC3 station, enlarging the range

  1. Comparison of the meteorology and surface energy balance at Storbreen and Midtdalsbreen, two glaciers in southern Norway

    Directory of Open Access Journals (Sweden)

    R. H. Giesen

    2008-12-01

    Full Text Available We compare 5 years of meteorological records from automatic weather stations (AWSs on Storbreen and Midtdalsbreen, two glaciers in southern Norway, located approximately 120 km apart. The records are obtained from identical AWSs with an altitude difference of 130 m and cover the period September 2001 to September 2006. Air temperature at the AWS locations is found to be highly correlated, even with the seasonal cycle removed. The most striking difference between the two sites is the difference in wind climate. Midtdalsbreen is much more under influence of the large-scale circulation with wind speeds on average a factor 1.75 higher. On Storbreen, weaker katabatic winds are dominant. The main melt season is from May to September at both locations. During the melt season, incoming and net solar radiation are larger on Midtdalsbreen, whereas incoming and net longwave radiation are larger on Storbreen, primarily caused by thicker clouds on the latter. The turbulent fluxes are a factor 1.7 larger on Midtdalsbreen, mainly due to the higher wind speeds. Inter-daily fluctuations in the surface energy fluxes are very similar at the AWS sites. On average, melt energy is a factor 1.3 larger on Midtdalsbreen, a result of both larger net radiation and larger turbulent fluxes. The relative contribution of net radiation to surface melt is larger on Storbreen (76% than on Midtdalsbreen (66%. As winter snow depth at the two locations is comparable in most years, the larger amount of melt energy results in an earlier disappearance of the snowpack on Midtdalsbreen and 70% more ice melt than on Storbreen. We compare the relative and absolute values of the energy fluxes on Storbreen and Midtdalsbreen with reported values for glaciers at similar latitudes. Furthermore, a comparison is made with meteorological variables measured at two nearby weather stations, showing that on-site measurements are essential for an accurate calculation of the surface energy balance and

  2. Comparison of the meteorology and surface energy balance at Storbreen and Midtdalsbreen, two glaciers in southern Norway

    Directory of Open Access Journals (Sweden)

    R. H. Giesen

    2009-03-01

    Full Text Available We compare 5 years of meteorological records from automatic weather stations (AWSs on Storbreen and Midtdalsbreen, two glaciers in southern Norway, located approximately 120 km apart. The records are obtained from identical AWSs with an altitude difference of 120 m and cover the period September 2001 to September 2006. Air temperature at the AWS locations is found to be highly correlated, even with the seasonal cycle removed. The most striking difference between the two sites is the difference in wind climate. Midtdalsbreen is much more under influence of the large-scale circulation with wind speeds on average a factor 1.75 higher. On Storbreen, weaker katabatic winds are dominant. The main melt season is from May to September at both locations. During the melt season, incoming and net solar radiation are larger on Midtdalsbreen, whereas incoming and net longwave radiation are larger on Storbreen, primarily caused by thicker clouds on the latter. The turbulent fluxes are a factor 1.7 larger on Midtdalsbreen, mainly due to the higher wind speeds. Inter-daily fluctuations in the surface energy fluxes are very similar at the AWS sites. On average, melt energy is a factor 1.3 larger on Midtdalsbreen, a result of both larger net radiation and larger turbulent fluxes. The relative contribution of net radiation to surface melt is larger on Storbreen (76% than on Midtdalsbreen (66%. As winter snow depth at the two locations is comparable in most years, the larger amount of melt energy results in an earlier disappearance of the snowpack on Midtdalsbreen and 70% more ice melt than on Storbreen. We compare the relative and absolute values of the energy fluxes on Storbreen and Midtdalsbreen with reported values for glaciers at similar latitudes. Furthermore, a comparison is made with meteorological variables measured at two nearby weather stations, showing that on-site measurements are essential for an accurate calculation of the surface energy balance and

  3. Estimation of surface-wave phase velocity from microtremor observation using an array with a reference station

    Science.gov (United States)

    Yamanaka, Hiroaki; Kato, Kei; Chimoto, Kosuke; Tsuno, Seiji

    2015-09-01

    A procedure for estimation of Rayleigh wave phase velocities from microtremor observations, using an array with a reference station, is investigated in this study. Simultaneous observation of microtremors at a reference station and at a strong motion observation array in the Kanto Basin, Japan, was carried out. We first calculated cross correlations between records at the reference station and those at stations in the array using a seismic interferometric processing method on a 4300-h data series. After identifying dispersive Rayleigh waves from results of multiple filtering analysis of the cross correlations, semblance analysis of the cross correlations for different segments was carried out to estimate phase velocities for fundamental and higher-mode Rayleigh waves. The phase velocities from the proposed method are more appropriate than those from conventional methods at long periods as they avoid contamination by higher mode Rayleigh waves. The fundamental Rayleigh wave phase velocities were inverted to an S-wave velocity profile for deep sedimentary layers. We also examined the variations in the phase velocity with decreasing data duration. The phase velocities at periods less than 3 s from 6-h records are similar to those from 4300-h records, suggesting that our method is possibly applicable in microtremor exploration.

  4. Reconstruction of erythemal UV-doses for two stations in Austria: a comparison between alpine and urban regions

    Directory of Open Access Journals (Sweden)

    H. E. Rieder

    2008-10-01

    Full Text Available The aim of this study is the reconstruction of past UV-doses for two stations in Austria, Hoher Sonnblick and Vienna, using a physical radiation transfer model. The method uses the modeled UV-dose under clear-sky conditions, cloud modification factors and a correction factor as input variables. To identify the influence of temporal resolution of input data and modification factors, an ensemble of four different modelling approaches was calculated, each with hourly or daily resolution. This is especially important because we found no other study describing the influence of the temporal resolution of input data on model performance. Following the results of the statistical analysis of the evaluation period the model with the highest temporal resolution (HMC was chosen for the reconstruction of UV-doses. A good agreement between modelled and measured values of erythemally effective UV-doses was found at both stations. In relation to the reference period 1976–1985 an increase in the erythemal UV-dose in Vienna of 11% is visible in the period 1986–1995 and an increase of 17% in the period 1996–2005 can be seen. At Hoher Sonnblick the corresponding increase is 2% and 9%. For the different seasons the strongest increase in erythemal UV-dose has been found for winter and spring season at both stations. Further the influences of total ozone and cloudiness on changes in erythemal UV-doses were analyzed. This analysis showed for both stations, that changes in total ozone had a larger influence on erythemal UV-doses than changes in cloudiness.

  5. ASOS Station Photos

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The images contained in this library are of stations in the Automated Surface Observing System (ASOS) network. These images were taken between 1998-2001 for the ASOS...

  6. Comparison of radioactivity data measured in PM10 aerosol samples at two elevated stations in northern Italy during the Fukushima event.

    Science.gov (United States)

    Tositti, Laura; Brattich, Erika; Cinelli, Giorgia; Previti, Alberto; Mostacci, Domiziano

    2012-12-01

    The follow-up of Fukushima radioactive plume resulting from the 11th March 2011 devastating tsunami is discussed for two Italian stations in the northern Apennines: Mt. Cimone (Modena) and Montecuccolino (Bologna). Radioactivity data collected at both stations are described, including comparison between local natural background of airborne particulate and artificial radioactivity referable to the arrival of the radioactive plume and its persistence and evolution. Analysis of back-trajectories was used to confirm the arrival of artificial radionuclides following atmospheric transport and processing. The Fukushima plume was first detected on 3rd April 2011 when high volume sampling revealed the presence of the artificial radionuclides (131)I, (137)Cs and (134)Cs. The highest activity concentrations of these nuclides were detected on 5th April 2011 at the Montecuccolino site. Fukushima radioactivity data at the two stations were usually comparable, suggesting a good vertical mixing of the plume; discrepancies were occasional and attributed to different occurrence of wet removal, typically characterized by a scattered spatial pattern. To understand the relevance to the local population of the extra dose due to the Fukushima plume, atmospheric activities of the related artificial nuclides were compared to those of the main natural radionuclides in ambient particulate, and found to be lower by over one order of magnitude. Radiation doses referable to Fukushima, maximized for a whole year occurrence at the highest activity level observed at our stations in the weeks affected by the Japanese plume, were estimated at 1.1 μSv/year. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Sevoflurane Remifentanil Interaction Comparison of Different Response Surface Models

    NARCIS (Netherlands)

    Heyse, Bjorn; Proost, Johannes H.; Schumacher, Peter M.; Bouillon, Thomas W.; Vereecke, Hugo E. M.; Eleveld, Douglas J.; Luginbuehl, Martin; Struys, Michel M. R. F.

    2012-01-01

    Background: Various pharmacodynamic response surface models have been developed to quantitatively describe the relationship between two or more drug concentrations with their combined clinical effect. We examined the interaction of remifentanil and sevoflurane on the probability of tolerance to shak

  8. A comparison of surface fluxes at the HAPEX-Sahel fallow bush sites.

    NARCIS (Netherlands)

    Lloyd, C.R.; Bessemoulin, P.; Cropley, F.D.; Culf, A.D.; Dolman, A.J.; Elbers, J.; Moncrieff, J.; Monteny, B.; Verhoef, A.

    1997-01-01

    The variability between surface flux measurements at the fallow sites of the three HAPEX-Sahel supersites is examined over periods of three or four consecutive days. A roving eddy correlation instrument provided a common base for comparison at each supersite. The inhomogeneity of the surface and the

  9. Comparison of Three Methods for Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (Postprint)

    Science.gov (United States)

    2011-04-01

    AFRL-RX-TY-TP-2010-0076 COMPARISON OF THREE METHODS FOR GENERATING SUPERHYDROPHOBIC, SUPEROLEOPHOBIC NYLON NONWOVEN SURFACES Rahul Saraf...Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (POSTPRINT) FA8650-07-1-5916 0602102F GOVT L0 QL102006 ^Saraf, Rahul,; ^Lee, Hoon...three different techniques to achieve superhydrophobicity and superoleophobicity using hydroentangled nylon nonwoven fabric: pulsed plasma polymerization

  10. Comparison of optical methods for surface roughness characterization

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft; Hansen, Poul Erik; Pilny, Lukas;

    2015-01-01

    We report a study of the correlation between three optical methods for characterizing surface roughness: a laboratory scatterometer measuring the bi-directional reflection distribution function (BRDF instrument), a simple commercial scatterometer (rBRDF instrument), and a confocal optical profiler....... For each instrument, the effective range of spatial surface wavelengths is determined, and the common bandwidth used when comparing the evaluated roughness parameters. The compared roughness parameters are: the root-mean-square (RMS) profile deviation (Rq), the RMS profile slope (Rdq), and the variance...

  11. An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments

    DEFF Research Database (Denmark)

    Tosello, Guido; Haitjema, H.; Leach, R.K.

    2016-01-01

    scanning interferometers) from thirteen research laboratories worldwide. Results demonstrated that: (i)Agreement among different instruments could be achieved to a limited extent; (ii) standardisedguidelines for uncertainty evaluation of areal surface parameters are needed for users; (iii......An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent......) it is essentialthat the performance characteristics (and especially the spatial frequency response) of an instrument isunderstood prior to a measurement....

  12. A comparison of all-weather land surface temperature products

    Science.gov (United States)

    Martins, Joao; Trigo, Isabel F.; Ghilain, Nicolas; Goettche, Frank-M.; Ermida, Sofia; Olesen, Folke-S.; Gellens-Meulenberghs, Françoise; Arboleda, Alirio

    2017-04-01

    The Satellite Application Facility on Land Surface Analysis (LSA-SAF, http://landsaf.ipma.pt) has been providing land surface temperature (LST) estimates using SEVIRI/MSG on an operational basis since 2006. The LSA-SAF service has since been extended to provide a wide range of satellite-based quantities over land surfaces, such as emissivity, albedo, radiative fluxes, vegetation state, evapotranspiration, and fire-related variables. Being based on infra-red measurements, the SEVIRI/MSG LST product is limited to clear-sky pixels only. Several all-weather LST products have been proposed by the scientific community either based on microwave observations or using Soil-Vegetation-Atmosphere Transfer models to fill the gaps caused by clouds. The goal of this work is to provide a nearly gap-free operational all-weather LST product and compare these approaches. In order to estimate evapotranspiration and turbulent energy fluxes, the LSA-SAF solves the surface energy budget for each SEVIRI pixel, taking into account the physical and physiological processes occurring in vegetation canopies. This task is accomplished with an adapted SVAT model, which adopts some formulations and parameters of the Tiled ECMWF Scheme for Surface Exchanges over Land (TESSEL) model operated at the European Center for Medium-range Weather Forecasts (ECMWF), and using: 1) radiative inputs also derived by LSA-SAF, which includes surface albedo, down-welling fluxes and fire radiative power; 2) a land-surface characterization obtained by combining the ECOCLIMAP database with both LSA-SAF vegetation products and the H(ydrology)-SAF snow mask; 3) meteorological fields from ECMWF forecasts interpolated to SEVIRI pixels, and 4) soil moisture derived by the H-SAF and LST from LSA-SAF. A byproduct of the SVAT model is surface skin temperature, which is needed to close the surface energy balance. The model skin temperature corresponds to the radiative temperature of the interface between soil and atmosphere

  13. Comparison Study on Thermal-Hydraulic Analysis Depending on Liquid Relief Valve Response for an Station Blackout in CANDU-6

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. M.; Kho, D. W. [KHNP-CRI, Daejeon (Korea, Republic of); Choi, S. H.; Moon, B. J.; Kim, S. R. [Nuclear Engineering Service and Solution Co., Daejeon (Korea, Republic of)

    2014-10-15

    The purpose of this analysis is to compare the results of thermal-hydraulic analysis depending on liquid relief valve response during a station black out (SBO) events in CANDU-6. The primary heat transport system (PHTS) behavior following the postulated SBO is analyzed using CATHENA code. In the paper, analysis was performed to evaluate the effect on coolant system where LRVs are assumed to be opened or opened according to normal open characteristics in the condition of SBO. The result showed that the primary pressure boundary is extended from LRV to DCT and the effects on primary system behavior were neglectable.

  14. Comparison of several innovative bridge cable surface modifications

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos T.

    Over the last two decades, several bridge cable manufacturers have introduced surface modifications on the high-density polyethylene (HDPE) sheathing that is installed for the protection of inner cable strands or wires. The modifications are based on research undertaken predominantly in Europe an...

  15. Comparison of cluster expansion fitting algorithms for interactions at surfaces

    Science.gov (United States)

    Herder, Laura M.; Bray, Jason M.; Schneider, William F.

    2015-10-01

    Cluster expansions (CEs) are Ising-type interaction models that are increasingly used to model interaction and ordering phenomena at surfaces, such as the adsorbate-adsorbate interactions that control coverage-dependent adsorption or surface-vacancy interactions that control surface reconstructions. CEs are typically fit to a limited set of data derived from density functional theory (DFT) calculations. The CE fitting process involves iterative selection of DFT data points to include in a fit set and selection of interaction clusters to include in the CE. Here we compare the performance of three CE fitting algorithms-the MIT Ab-initio Phase Stability code (MAPS, the default in ATAT software), a genetic algorithm (GA), and a steepest descent (SD) algorithm-against synthetic data. The synthetic data is encoded in model Hamiltonians of varying complexity motivated by the observed behavior of atomic adsorbates on a face-centered-cubic transition metal close-packed (111) surface. We compare the performance of the leave-one-out cross-validation score against the true fitting error available from knowledge of the hidden CEs. For these systems, SD achieves lowest overall fitting and prediction error independent of the underlying system complexity. SD also most accurately predicts cluster interaction energies without ignoring or introducing extra interactions into the CE. MAPS achieves good results in fewer iterations, while the GA performs least well for these particular problems.

  16. Posttonsillectomy Bacteremia and Comparison of Tonsillar Surface and Deep Culture

    Directory of Open Access Journals (Sweden)

    Mahmood Shishegar

    2014-01-01

    Full Text Available Objective. This study aimed to identify the microorganisms of surface and depth of tonsils and whether these microorganisms bring the menace of bacteremia during tonsillectomy in the children under surgery. Materials and Methods. The culture specimens were taken from surface and depth of tonsil from the patients suffering from chronic tonsillitis at the time of operation. Also, 10 mL venous blood samples were taken 5 minutes before and after the operation for microbiological study. Results. According to the results, 112 (76.1% and 117 (79.6% cultures from surface and depth of tonsils represented multiple microorganisms, respectively. Besides, staphylococci coagulase positive was the most common organism in both surface and depth of tonsils. None of the preoperation blood cultures were positive, while 3 postoperation blood cultures (2.1% were positive. Staphylococci coagulase negative and alpha hemolytic streptococcus were detected in 2 cases (1.4% and 1 case (0.7%, respectively. Conclusion. In the present study, the two cultured sites were almost similar regarding the types of isolated microorganisms. Our results suggested that bacteremia might occur after tonsillectomy. Therefore, to avoid the possible dramatic outcomes after tonsillectomy, pre- and postoperation attendances are essential.

  17. A comparison of surface properties of metallic thin film photocathodes

    CERN Document Server

    Mistry, Sonal; Valizadeh, Reza; Jones, L.B; Middleman, Keith; Hannah, Adrian; Militsyn, B.L; Noakes, Tim

    2017-01-01

    In this work the preparation of metal photocathodes by physical vapour deposition magnetron sputtering has been employed to deposit metallic thin films onto Cu, Mo and Si substrates. The use of metallic cathodes offers several advantages: (i) metal photocathodes present a fast response time and a relative insensitivity to the vacuum environment (ii) metallic thin films when prepared and transferred in vacuum can offer smoother and cleaner emitting surfaces. The photocathodes developed here will ultimately be used in S-band Normal Conducting RF (NCRF) guns such as that used in VELA (Versatile Electron Linear Accelerator) and the proposed CLARA (Compact Linear Accelerator for Research and Applications) Free Electron Laser test facility. The samples grown on Si substrates were used to investigate the morphology and thickness of the film. The samples grown onto Cu and Mo substrates were analysed and tested as photocathodes in a surface characterisation chamber, where X-Ray Photoelectron spectroscopy (XPS) was em...

  18. Comparison of the effectiveness of different antimicrobial surface technologies

    Directory of Open Access Journals (Sweden)

    Buhl Sebastian

    2017-09-01

    Full Text Available The risk of infection via microbiologically contaminated surfaces has already been demonstrated by other publications. In this work two different antibacterial surface technologies transition metalloacids (AMiSTec and TiO2/AgNO3 (Health Complete were compared regarding feasibility as well as their advantages and disadvantages. The examination of the antimicrobial activity was assessed according to the JIS Z 2801. We could demonstrate that all of our tested samples showed a strong antimicrobial activity (>log 3 germ reduction in the JIS experiments. Furthermore this strong antibacterial effect could be shown already after <30min incubation and at low light intensity (approx. 300 Lux for the TiO2/AgNO3 samples. Both technologies provide a high potential for an improved infection control for example in a high risk environment like operation rooms or intensive care units.

  19. Comparison of alternative concepts for lunar surface transportation

    Science.gov (United States)

    Apel, Uwe

    The lunar surface transportation system is a key element in lunar development. The decision which means of conveyance should be preferred depends on a lot of influencing factors such as transportation requirements, physical boundary conditions and economics. Starting with a systematic approach to define and structure the problem, a model to compare alternative transportation systems has been built. From the pool of possible means of conveyance, chemical rockets, electric cars, maglev-trains and mass-drivers have been chosen as candidates for investigation. With these candidates five different surface transportation systems were defined. For a reference lunar development scenario the systems were compared on the basis of a cost-to-benefit ratio. Preliminary results indicate that under the assumption that LH2 could be produced on lunar surface, LOX/LH2 propulsed "Hoppers" seem very attractive up to medium transportation demands. For large amounts of bulk cargo, mass driver transportation seems to have advantages, and electric cars should be used for all transportation tasks if the transportation demand is high. Maglev-trains seem to be competitive only for very large transportation demand and long life cycles.

  20. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during February 2016 (NCEI Accession 0145743)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  1. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during April 2016 (NCEI Accession 0151726)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  2. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during February 2015 (NCEI Accession 0131074)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  3. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during March 2015 (NCEI Accession 0131884)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  4. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during May 2016 (NCEI Accession 0154389)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  5. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during March 2016 (NCEI Accession 0148078)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  6. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during April 2015 (NCEI Accession 0138389)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  7. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during May 2015 (NCEI Accession 0138488)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  8. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during December 2015 (NCEI Accession 0141105)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  9. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during March 2015 (NCEI Accession 0138305)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  10. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during July 2016 (NCEI Accession 0156405)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  11. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during January 2015 (NCEI Accession 0137088)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  12. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during April 2015 (NCEI Accession 0131908)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  13. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during May 2016 (NCEI Accession 0154390)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  14. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during February 2016 (NCEI Accession 0145802)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  15. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during January 2016 (NCEI Accession 0144289)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  16. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during June 2015 (NCEI Accession 0138584)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  17. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during June 2015 (NCEI Accession 0131956)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  18. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during January 2016 (NCEI Accession 0144286)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  19. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during December 2015 (NCEI Accession 0141107)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  20. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during June 2016 (NCEI Accession 0155978)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  1. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during September 2015 (NCEI Accession 0138948)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  2. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during August 2016 (NCEI Accession 0156626)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  3. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during April 2016 (NCEI Accession 0151734)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  4. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during November 2015 (NCEI Accession 0139553)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  5. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during October 2015 (NCEI Accession 0139156)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  6. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during May 2015 (NCEI Accession 0131932)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  7. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during June 2016 (NCEI Accession 0155984)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  8. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during January 2015 (NCEI Accession 0129913)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  9. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during February 2015 (NCEI Accession 0137265)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  10. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during July 2015 (NCEI Accession 0138671)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  11. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during August 2015 (NCEI Accession 0138776)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  12. Surface ocean velocities obtained by HF radar from stations located along coastal waters of Antarctica, Hawaii, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico and western US during March 2016 (NCEI Accession 0148080)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The archival package contains ocean surface radial velocities collected from High frequency (HF) radar stations. NDBC, which with SIO assembles data from the IOOS HF...

  13. Comparison of surface fractal dimensions of chromizing coating and P110 steel for corrosion resistance estimation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Naiming, E-mail: lnmlz33@163.com [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Guo, Junwen [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Xie, Faqin [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Zou, Jiaojuan; Tian, Wei [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Yao, Xiaofei [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Zhang, Hongyan; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2014-08-30

    Highlights: • Continuous chromizing coating was synthesized on P110 steel by pack cementation. • The chromizing coating showed better corrosion resistance. • Comparison of surface fractal dimensions can estimate corrosion resistance. - Abstract: In the field of corrosion research, mass gain/loss, electrochemical tests and comparing the surface elemental distributions, phase constitutions as well as surface morphologies before and after corrosion are extensively applied to investigate the corrosion behavior or estimate the corrosion resistance of materials that operated in various environments. Most of the above methods are problem oriented, complex and longer-period time-consuming. However from an object oriented point of view, the corroded surfaces of materials often have self-similar characterization: fractal property which can be employed to efficiently achieve damaged surface analysis. The present work describes a strategy of comparison of the surface fractal dimensions for corrosion resistance estimation: chromizing coating was synthesized on P110 steel surface to improve its performance via pack cementation. Scanning electron microscope (SEM) was used to investigate the surface morphologies of the original and corroded samples. Surface fractal dimensions of the detected samples were calculated by binary images related to SEM images of surface morphologies with box counting algorithm method. The results showed that both surface morphologies and surface fractal dimensions of P110 steel varied greatly before and after corrosion test, but the chromizing coating changed slightly. The chromizing coating indicated better corrosion resistance than P110 steel. Comparison of surface fractal dimensions of original and corroded samples can rapidly and exactly realize the estimation of corrosion resistance.

  14. Technical Note: Downscaling RCM precipitation to the station scale using quantile mapping – a comparison of methods

    Directory of Open Access Journals (Sweden)

    L. Gudmundsson

    2012-05-01

    Full Text Available The impact of climate change on water resources is usually assessed at the local scale. However, regional climate models (RCM are known to exhibit systematic biases in precipitation. Hence, RCM simulations need to be post-processed in order to produce reliable estimators of local scale climate. A popular post-processing approach is quantile mapping (QM, which is designed to adjust the distribution of modeled data, such that it matches observed climatologies. However, the diversity of suggested QM methods renders the selection of optimal techniques difficult and hence there is a need for clarification. In this paper, QM methods are reviewed and classified into: (1 distribution derived transformations, (2 parametric transformations and (3 nonparametric transformations; each differing with respect to their underlying assumptions. A real world application, using observations of 82 precipitation stations in Norway, showed that nonparametric transformations have the highest skill in systematically reducing biases in RCM precipitation.

  15. Between-event and between-station variability observed in the Fourier and response spectra domains: comparison with seismological models

    Science.gov (United States)

    Bindi, D.; Spallarossa, D.; Pacor, F.

    2017-08-01

    In this study, we analyse a regional data set composed by about 9000 waveforms from 231 earthquakes in the magnitude range from 3 to 6 and recorded in central Italy in the time period 2008-2013. We derive a seismological model whose source, attenuation and site parameters are used to explain the ground motion variability associated with a set of ground motion prediction equation (GMPE) calibrated ad hoc for both Fourier and acceleration response spectra. The main results are the following: (1) the between-event residuals δΒe show a clear dependence on the stress drop for frequencies above 2 Hz; (2) the standard deviation τ of δΒe is strongly reduced (up to 80 per cent) by introducing in the functional form the stress drop values estimated from each source spectrum; (3) the standard deviation τ depends on the magnitude scale used to calibrate the GMPE: while the moment magnitude better describes the source variability at low frequency, the local magnitude better capture the source-related ground motion variability at frequencies larger than 2 Hz; (4) for frequencies higher than 10 Hz, the observed increase of τ with frequency correlate well with the attenuation parameter ksource, computed from the high-frequency slope of the source spectra. Regarding the station-to-station residuals δS2S, their frequency dependency is in good agreement with the site amplifications extracted from the S-wave spectra. Finally, while the overall dependences of the ground motion variability on seismological parameters are similar when observed either in the Fourier or in the response spectra domains (e.g. the dependency of the between event on stress drop), differences in the results suggest that the response spectra do not allow to fully capture the ground motion variability, as well as the site amplifications, at high frequencies.

  16. Comparison of contrast-enhanced multi-station MR angiography and digital subtraction angiography of the lower extremity arterial disease.

    Science.gov (United States)

    Burbelko, Mykhaylo; Augsten, Michael; Kalinowski, Marc O; Heverhagen, Johannes T

    2013-06-01

    To compare diagnostic accuracy of multi-station, high-spatial resolution contrast-enhanced MR angiography (CE-MRA) of the lower extremities with digital subtraction angiography (DSA) as the reference standard in patients with symptomatic peripheral arterial occlusive disease. Of 485 consecutive patients undergoing a run-off CE-MRA, 152 patients (86 male, 66 female; mean age, 71.6 years) with suspected peripheral arterial occlusive disease were included into our Institutional Review Board approved study. All patients underwent MRA and DSA of the lower extremities within 30 days. MRA was performed at 1.5 Tesla with a single bolus of 0.1 mmol/kg body weight of gadobutrol administered at a rate of 2.0 mL/s at three stations. Two readers evaluated the MRA images independently for stenosis grade and image quality. Sensitivity and specificity were derived. Sensitivity and specificity ranged from 73% to 93% and 64% to 89% and were highest in the thigh area. Both readers showed comparable results. Evaluation of good and better quality MRAs resulted in a considerable improvement in diagnostic accuracy. Contrast-enhanced MRA demonstrates good sensitivity and specificity in the investigation of the vasculature of the lower extremities. While a minor investigator experience dependence remains, it is standardizable and shows good inter-observer agreement. Our results confirm that the administration of Gadobutrol at a standard dose of 0.1 mmol/kg for contrast-enhanced runoff MRA is able to detect hemodynamically relevant stenoses. Use of contrast-enhanced MRA as an alternative to intra-arterial DSA in the evaluation and therapeutic planning of patients with suspected peripheral arterial occlusive disease is well justified. Copyright © 2012 Wiley Periodicals, Inc.

  17. Comparison of fipronil sources in North Carolina surface water ...

    Science.gov (United States)

    Fipronil is a phenylpyrazole insecticide that is widely used in residential and agricultural settings to control ants, roaches, termites, and other pests. Fipronil and its transformation products have been found in a variety of environmental matrices, but the source[s] which makes the greatest contribution to fipronil in surface water has yet to be determined. A sampling effort designed to prioritize known fipronil inputs (golf courses, residential areas, biosolids application sites and wastewater facilities) was conducted in North Carolina to learn more about the origins of fipronil in surface water. High resolution mass spectrometry (HRMS) analysis indicated that fipronil and its known derivatives were routinely present in all samples, but concentrations were substantially elevated near wastewater treatment plant outfalls (range 10–500 ng/L combined), suggesting that they predominate as environmental sources. Corresponding recycled wastewater samples, which were treated with NaOCl for disinfection, showed disappearance of fipronil and all known degradates. HRMS and nuclear magnetic resonance (NMR) analysis techniques were used to determine that all fipronil-related compounds are oxidized to a previously unidentified fipronil sulfone chloramine species in recycled wastewater. The implications of the presence of a new fipronil-related compound in recycled wastewater need to be considered. Journal Article Highlights • The most important sources of fipronil in

  18. Comparison of discrete Hodge star operators for surfaces

    KAUST Repository

    Mohamed, Mamdouh S.

    2016-05-10

    We investigate the performance of various discrete Hodge star operators for discrete exterior calculus (DEC) using circumcentric and barycentric dual meshes. The performance is evaluated through the DEC solution of Darcy and incompressible Navier–Stokes flows over surfaces. While the circumcentric Hodge operators may be favorable due to their diagonal structure, the barycentric (geometric) and the Galerkin Hodge operators have the advantage of admitting arbitrary simplicial meshes. Numerical experiments reveal that the barycentric and the Galerkin Hodge operators retain the numerical convergence order attained through the circumcentric (diagonal) Hodge operators. Furthermore, when the barycentric or the Galerkin Hodge operators are employed, a super-convergence behavior is observed for the incompressible flow solution over unstructured simplicial surface meshes generated by successive subdivision of coarser meshes. Insofar as the computational cost is concerned, the Darcy flow solutions exhibit a moderate increase in the solution time when using the barycentric or the Galerkin Hodge operators due to a modest decrease in the linear system sparsity. On the other hand, for the incompressible flow simulations, both the solution time and the linear system sparsity do not change for either the circumcentric or the barycentric and the Galerkin Hodge operators.

  19. [Study on pollution evaluation of heavy metal in surface soil of the original site of Qingdao North Station].

    Science.gov (United States)

    Zhu, Lei; Jia, Yong-gang; Pan, Yu-ying

    2013-09-01

    The determination of pollution extent and health risk assessment are the premise of heavy metal contaminated site remediation. The content of Cu, Cr, Pb, Cd, Zn, Ni in Qingdao North Station was detected, and the correlation of the 6 kinds of heavy metal content was analyzed. The pollution extent in excess of background values was characterized by anthropogenic influence multiple, and the pollution of heavy metal in soil was evaluated using geoaccumulation index and a new method which connects geoaccumulation index with Nemero index. Finally, human health risk assessment was carried out with health risk assessment model for heavy metal content. The results showed that Qingdao North Station soil were polluted by heavy metals. Six heavy metal pollution levels were: Cd > Cu > Ni > Pb > Cr > Zn, and Cd had reached the severity pollution level, Cu and Ni followed by, Cr, Pb and Zn were in minor pollution level. The order of coefficient variation in all heavy metals was: Cd > Ni > Cr > Zn > Pb > Cu. Within the study area soil heavy metal distribution was different, but overall discrepancy was small. The order of non-cancer hazards of heavy metals in soil was Cr > Pb > Cu > Ni > Cd > Zn, and the order of carcinogen risks of heavy metals was Ni > Cd. The non-cancer hazard and carcinogen risks values of metals were both lower than that their threshold values. They were not the direct threats to human health.

  20. Infrasound observations at Syowa Station, East Antarctica: Implications for detecting the surface environmental variations in the polar regions

    Directory of Open Access Journals (Sweden)

    Yoshiaki Ishihara

    2015-03-01

    Full Text Available Characteristic infrasound waves observed at Antarctic stations demonstrate physical interaction involving environmental changes in the Antarctic continent and the surrounding oceans. A Chaparral-type infrasound sensor was installed at Syowa Station (SYO; 39°E, 69°S, East Antarctica, as one of the projects of the International Polar Year (IPY2007‒2008. Data continuously recorded during the three seasons in 2008–2010 clearly indicate a contamination of the background oceanic signals (microbaroms with peaks between 4 and 10 s observed during a whole season. The peak amplitudes of the microbaroms have relatively lower values during austral winters, caused by a larger amount of sea-ice extending around the Lützow-Holm Bay near SYO, with decreasing ocean wave loading effects. Microbaroms measurements are useful tool for characterizing ocean wave climate, complementing other oceanographic and geophysical data. A continuous monitoring by infrasound sensors in the Antarctic firmly contributes to the Comprehensive Nuclear-Test-Ban Treaty (CTBT in the southern high latitude, together with the Pan-Antarctic Observations System (PAntOS under the Scientific Committee on Antarctic Research (SCAR. Detailed measurements of the infrasound waves in Antarctica, consequently, could be a new proxy for monitoring regional environmental change as well as the temporal climate variations in the polar regions.

  1. SURFEX modeling of soil moisture fields over the Valencia Anchor Station and their comparison to different SMOS products and in situ measurements

    Science.gov (United States)

    Coll Pajaron, M. Amparo; Lopez-Baeza, Ernesto; Fernandez-Moran, Roberto; Samiro Khodayar-Pardo, D.

    2016-07-01

    Soil moisture is a difficult variable to obtain proper representation because of its high temporal and spatial variability. It is a significant parameter in agriculture, hydrology, meteorology and related disciplines. {it SVAT (Soil-Vegetation-Atmosphere-Transfer)} models can be used to simulate the temporal behaviour and spatial distribution of soil moisture in a given area. In this work, we use the {bf SURFEX (Surface Externalisée)} model developed at the {it Centre National de Recherches Météorologiques (CNRM)} at Météo-France (http://www.cnrm.meteo.fr/surfex/) to simulate soil moisture at the {bf Valencia Anchor Station}. SURFEX integrates the {bf ISBA (Interaction Sol-Biosphère-Atmosphère}; surfaces with vegetation) module to describe the land surfaces (http://www.cnrm.meteo.fr/isbadoc/model.html) that have been adapted to describe the land covers of our study area. The Valencia Anchor Station was chosen as a core validation site for the {it SMOS (Soil Moisture and Ocean Salinity)} mission and as one of the hydrometeorological sites for the {it HyMeX (HYdrological cycle in Mediterranean EXperiment)} programme. This site represents a reasonably homogeneous and mostly flat area of about 50x50 km2. The main cover type is vineyards (65%), followed by fruit trees, shrubs, and pine forests, and a few small scattered industrial and urban areas. Except for the vineyard growing season, the area remains mostly under bare soil conditions. In spite of its relatively flat topography, the small altitude variations of the region clearly influence climate. This oscillates between semiarid and dry sub-humid. Annual mean temperatures are between 12 ºC and 14.5 ºC, and annual precipitation is about 400-450 mm. The duration of frost free periods is from May to November, with maximum precipitation in spring and autumn. The first part of this investigation consists in simulating soil moisture fields over the Valencia Anchor Station to be compared with SMOS level-2

  2. Accuracy assessment of land surface temperature retrievals from Landsat 7 ETM + in the Dry Valleys of Antarctica using iButton temperature loggers and weather station data.

    Science.gov (United States)

    Brabyn, Lars; Zawar-Reza, Peyman; Stichbury, Glen; Cary, Craig; Storey, Bryan; Laughlin, Daniel C; Katurji, Marwan

    2014-04-01

    The McMurdo Dry Valleys of Antarctica are the largest snow/ice-free regions on this vast continent, comprising 1% of the land mass. Due to harsh environmental conditions, the valleys are bereft of any vegetation. Land surface temperature is a key determinate of microclimate and a driver for sensible and latent heat fluxes of the surface. The Dry Valleys have been the focus of ecological studies as they arguably provide the simplest trophic structure suitable for modelling. In this paper, we employ a validation method for land surface temperatures obtained from Landsat 7 ETM + imagery and compared with in situ land surface temperature data collected from four transects totalling 45 iButtons. A single meteorological station was used to obtain a better understanding of daily and seasonal cycles in land surface temperatures. Results show a good agreement between the iButton and the Landsat 7 ETM + product for clear sky cases. We conclude that Landsat 7 ETM + derived land surface temperatures can be used at broad spatial scales for ecological and meteorological research.

  3. Station Capacity

    DEFF Research Database (Denmark)

    Landex, Alex

    2011-01-01

    Stations are often limiting the capacity of railway networks. This is due to extra need of tracks when trains stand still, trains turning around, and conflicting train routes. Although stations are often the capacity bottlenecks, most capacity analysis methods focus on open line capacity. Therefore......, this paper presents methods to analyze station capacity. Four methods to analyze station capacity are developed. The first method is an adapted UIC 406 capacity method that can be used to analyze switch zones and platform tracks at stations that are not too complex. The second method examines the need...... the probability of conflicts and the minimum headway times into account. The last method analyzes how optimal platform tracks are used by examining the arrival and departure pattern of the trains. The developed methods can either be used separately to analyze specific characteristics of the capacity of a station...

  4. Cross-satellite comparison of operational land surface temperature products derived from MODIS and ASTER data over bare soil surfaces

    Science.gov (United States)

    Duan, Si-Bo; Li, Zhao-Liang; Cheng, Jie; Leng, Pei

    2017-04-01

    The collection 6 (C6) MODIS land surface temperature (LST) product is publicly available for the user community. Compared to the collection 5 (C5) MODIS LST product, the C6 MODIS LST product has been refined over bare soil pixels. Assessing the accuracy of the C6 MODIS LST product will help to facilitate the use of the LST product in various applications. In this study, we present a cross-satellite comparison to evaluate the accuracy of the C6 MODIS LST product (MOD11_L2) over bare soil surfaces under various atmospheric and surface conditions using the ASTER LST product as a reference. For comparison, the C5 MODIS LST product was also used in the analysis. The absolute biases (0.2-1.5 K) of the differences between the C6 MODIS LST and ASTER LST over bare soil surfaces are approximately two times less than those (0.6-3.8 K) of the differences between the C5 MODIS LST and ASTER LST. Furthermore, the RMSEs (0.7-2.3 K) over bare soil surfaces for the C6 MODIS LST are significantly smaller than those (0.9-4.2 K) for the C5 MODIS LST. These results indicate that the accuracy of the C6 MODIS LST product is much better than that of the C5 MODIS LST product. We recommend that the user community employs the C6 MODIS LST product in their applications.

  5. Space Station

    Science.gov (United States)

    Anderton, D. A.

    1985-01-01

    The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited.

  6. Comparison of surface-derived and ISCCP cloud optical properties

    Science.gov (United States)

    Whitlock, C. H.; Poole, L. R.; Lecroy, S. R.; Rossow, W. B.; Bell, K. L.; Robinson, David A.; Grund, Christian J.

    1990-01-01

    One objective of the FIRE Project is to validate the cloud parameters given on ISCCP tapes. ISCCP first defines whether or not a region is clear or has clouds based on two threshold algorithms. If the region has clouds, then a cloud optical depth is given as well as a cloud height. Special high resolution ISCCP CX tapes were created for the time period of the Wisconsin FIRE experiment. These tapes did not include the cloud height product, however, other parameters used to make up the standard ISCCP Cl products were available. The ISCCP cloud/no cloud and cloud depth parameters are compared with surface derived values for the Wisconsin FIRE region during the October 27 and 28 case study days.

  7. Photoemission from Coated Surfaces A Comparison of Theory to Experiment

    CERN Document Server

    Jensen, K

    2005-01-01

    Photocathodes for FELs and accelerators will benefit from rugged and self-rejuvenating photocathodes with high QE at the longest possible wavelength. The needs of a high power FEL are not met at present by existing photocathode-drive laser combinations: requirements generally necessitate barrier-lowering coatings which are degraded by operation. We seek to develop a controlled porosity dispenser cathode, and shall report on our coordinated experimental and theoretical studies. Our models account for field, thermal, and surface effects of cesium monolayers on photoemission, and compare well with concurrent experiments examining the QE, patchiness, and evolution of the coatings. Field enhancement, thermal variation of specific heat and electron relaxation rates and their relation to high laser intensity and/or short pulse-to-pulse separation, variations in work function effects due to coating non-uniformity, and the dependence on the wavelength of the incident light are included. The status of methods by which ...

  8. Refractometric sensing using propagating versus localized surface plasmons: a direct comparison.

    Science.gov (United States)

    Svedendahl, Mikael; Chen, Si; Dmitriev, Alexandre; Käll, Mikael

    2009-12-01

    We present a direct experimental comparison between the refractive index sensing capabilities of localized surface plasmon resonances (LSPRs) in gold nanodisks and propagating surface plasmon resonances (SPRs) on 50 nm gold films. The comparison is made using identical experimental conditions, and for the same resonance wavelength, lambda(SP) congruent with 700 nm. Biosensing experiments with biotin-avidin coupling reveal that the two sensing platforms have very similar performance, despite a superior bulk refractive index sensing figure of merit for the SPR sensor. The results demonstrate that LSPR sensing based on simple transmission or reflection measurements is a highly competitive technique compared to the traditional SPR sensor.

  9. A comparison of two approaches to modelling snow cover dynamics at the Polish Polar Station at Hornsund

    Science.gov (United States)

    Luks, B.; Osuch, M.; Romanowicz, R. J.

    2012-04-01

    We compare two approaches to modelling snow cover dynamics at the Polish Polar Station at Hornsund. In the first approach we apply physically-based Utah Energy Balance Snow Accumulation and Melt Model (UEB) (Tarboton et al., 1995; Tarboton and Luce, 1996). The model uses a lumped representation of the snowpack with two primary state variables: snow water equivalence and energy. Its main driving inputs are: air temperature, precipitation, wind speed, humidity and radiation (estimated from the diurnal temperature range). Those variables are used for physically-based calculations of radiative, sensible, latent and advective heat exchanges with a 3 hours time step. The second method is an application of a statistically efficient lumped parameter time series approach to modelling the dynamics of snow cover , based on daily meteorological measurements from the same area. A dynamic Stochastic Transfer Function model is developed that follows the Data Based Mechanistic approach, where a stochastic data-based identification of model structure and an estimation of its parameters are followed by a physical interpretation. We focus on the analysis of uncertainty of both model outputs. In the time series approach, the applied techniques also provide estimates of the modeling errors and the uncertainty of the model parameters. In the first, physically-based approach the applied UEB model is deterministic. It assumes that the observations are without errors and that the model structure perfectly describes the processes within the snowpack. To take into account the model and observation errors, we applied a version of the Generalized Likelihood Uncertainty Estimation technique (GLUE). This technique also provide estimates of the modelling errors and the uncertainty of the model parameters. The observed snowpack water equivalent values are compared with those simulated with 95% confidence bounds. This work was supported by National Science Centre of Poland (grant no. 7879/B/P01

  10. Comparison of spatial interpolation methods for gridded bias removal in surface temperature forecasts

    Science.gov (United States)

    Mohammadi, Seyedeh Atefeh; Azadi, Majid; Rahmani, Morteza

    2017-08-01

    All numerical weather prediction (NWP) models inherently have substantial biases, especially in the forecast of near-surface weather variables. Statistical methods can be used to remove the systematic error based on historical bias data at observation stations. However, many end users of weather forecasts need bias corrected forecasts at locations that scarcely have any historical bias data. To circumvent this limitation, the bias of surface temperature forecasts on a regular grid covering Iran is removed, by using the information available at observation stations in the vicinity of any given grid point. To this end, the running mean error method is first used to correct the forecasts at observation stations, then four interpolation methods including inverse distance squared weighting with constant lapse rate (IDSW-CLR), Kriging with constant lapse rate (Kriging-CLR), gradient inverse distance squared with linear lapse rate (GIDS-LR), and gradient inverse distance squared with lapse rate determined by classification and regression tree (GIDS-CART), are employed to interpolate the bias corrected forecasts at neighboring observation stations to any given location. The results show that all four interpolation methods used do reduce the model error significantly, but Kriging-CLR has better performance than the other methods. For Kriging-CLR, root mean square error (RMSE) and mean absolute error (MAE) were decreased by 26% and 29%, respectively, as compared to the raw forecasts. It is found also, that after applying any of the proposed methods, unlike the raw forecasts, the bias corrected forecasts do not show spatial or temporal dependency.

  11. Evaluation of periodontal status adjacent to interproximal surfaces restored with composite resin, in comparison with non-restored interproximal surfaces

    Directory of Open Access Journals (Sweden)

    Elvia Christina Barros de Almeida

    2008-01-01

    Full Text Available Objective: The purpose of this study was to evaluate the periodontal status of interproximal surfaces restored with composite resin, in comparison with non-restored interproximal surfaces. Methods: In 65 patients, we analyzed 145 restored surfaces and 145 non-restored surfaces. Results: Most of the restored surfaces (54.3% showed radiographic alterations, which was shown to be higher among restorations with clinically detected proximal excess (56.8% x 52.8%; with lack of restorative material (64.5% x 51.4%; in restorations with proximal overhang (67.7% x 44.4%; in teeth with gingival inflammation?/bleeding (55.1% x 40.0% and in teeth with probing depth exceeding 3 mm (64.3% x 52.9%. However, there were no significant associations for these variables. Of the non-restored surfaces, 24.4% showed radiographic alterations, however there were no significant associations. Conclusion: The results showed a statistical significance for radiographic alterations in restored and non-restored surfaces.

  12. Comparison of remote sensing and in-situ soil moisture measurements: 6 years survey of SMOS data and agrometeorological stations in Eastern Poland

    Science.gov (United States)

    Szlazak, Radoslaw; Rojek, Edyta; Lukowski, Mateusz; Marczewski, Wojciech; Slominski, Jan; Sagan, Joanna; Gluba, Lukasz; Usowicz, Jerzy; Usowicz, Boguslaw

    2017-04-01

    Long term measurements of soil moisture on a large scale provide important information about not only periodical changes in water content, but also its contribute to better understanding of water cycle in environment. In addition, if in the studied area occurred extreme weather conditions or even anomalies, it is scientifically challenging to compare and validate data from two such different techniques like remote sensing and in-situ measurements. The aim of our research was to compare data of independent soil moisture measurements from SMOS (Soil Moisture and Ocean Salinity) satellite and 9 agrometeorological stations installed on Eastern Poland (Polesie and Podlasie regions). Those regions have similar climatic and topographic conditions, however, different vegetation covers and soil properties. Radiometric SMOS data contain surface water content values (approx. 45 km) for the area corresponding to the positions of chosen agrometeorological stations. For the purpose of those studies only morning satellite overpasses (ascending) were used. In-situ sensors in stations measure precisely soil moisture at 5-10 cm depth, but each only in one point. Both datasets were 7-days averaged in order to standardize. Analysis of a long term data is very interesting, especially because of occurrence of flood and drought events during the analyzed period of time. For example, the analyses revealed clear rainfall trend between ground and satellite data. Some shifts between SMOS and ground measurements were also observed, what may be explained by impact of different depths of SMOS measurements (Government of Poland through an ESA-PECS contract (Plan for European Cooperating States). 2) "Technical Support for the fabrication and deployment of the radiometer ELBARA-III in Bubnow, Poland" No. 4000113360/15/NL/FF/gp

  13. COMPARISON OF THE SHEAR BOND STRENGTH OF BRACKETS USING TWO SURFACE CONDITIONING METHODS FOR PORCELAIN

    OpenAIRE

    Ballesteros-Pinzón, Claudia; Bermúdez-Lozano, Jesús A.; Coronel-Corzo, Nelly; de-León-Goenaga, Edwin; Delgado, Linda P.; Báez-Quintero, Liliana

    2014-01-01

    Introduction: During 2010 the degree research “Comparison of the shear bond strength of brackets using two surface conditioning methods for porcelain” was carried out at Universidad Cooperativa de Colombia in Bogota. Objective: To determine the shear bond strength of metal brackets cemented on porcelain using two surface conditioning methods. Materials and methods: Forty human premolars were used and prepared for further cementing porcelain-metal crowns. There were two groups of 20 teeth each...

  14. A comparison of tool-repair methods using CO 2 laser surfacing and arc surfacing

    Science.gov (United States)

    Grum, J.; Slabe, J. M.

    2003-03-01

    The life of loaded machine elements and the vital parts of tools can be successfully extended by systematic maintenance and the timely repair of damaged surfaces. It has been proved that with the regular maintenance of tool parts the cost of the tool in the price of a finished product can be considerably reduced. It is a very economical practise to manufacture certain parts from low-cost, tough structural steel on which a layer of wear-resistant alloy has been surfaced. In such a case the volume fraction of the surfaced layer is usually much lower than 10% of the total volume of the tool or the machine element. In this paper, we report some of our latest results involving comparative studies of repair surfacing on maraging steel and the cladding of common structural steel with a Ni-Co-Mo alloy similar to the maraging steel using a laser process and submerged-arc surfacing. The results are based on micro-structural and micro-chemical analyses of the surfaced layer and are supported by analyses of the micro-hardness and the residual stresses, carried out on suitably adapted flat specimens.

  15. Station Capacity

    DEFF Research Database (Denmark)

    Landex, Alex

    2011-01-01

    Stations are often limiting the capacity of railway networks. This is due to extra need of tracks when trains stand still, trains turning around, and conflicting train routes. Although stations are often the capacity bottlenecks, most capacity analysis methods focus on open line capacity. Therefore......, this paper presents methods to analyze station capacity. Four methods to analyze station capacity are developed. The first method is an adapted UIC 406 capacity method that can be used to analyze switch zones and platform tracks at stations that are not too complex. The second method examines the need...... for platform tracks and the probability that arriving trains will not get a platform track immediately at arrival. The third method is a scalable method that analyzes the conflicts in the switch zone(s). In its simplest stage, the method just analyzes the track layout while the more advanced stages also take...

  16. Comparison of the regional CO2 mole fraction filtering approaches at a WMO/GAW regional station in China

    Science.gov (United States)

    Fang, S. X.; Tans, P. P.; Steinbacher, M.; Zhou, L. X.; Luan, T.

    2015-12-01

    The identification of atmospheric CO2 observation data which are minimally influenced by very local emissions/removals is essential for trend analysis, for the estimation of regional sources and sinks, and for the modeling of long-range transport of CO2. In this study, four approaches are used to filter the atmospheric CO2 observation records from 2009 to 2011 at one World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) regional station (Lin'an, LAN) in China. The methods are based on the concentration of atmospheric black carbon (BC), on a statistical approach (robust extraction of baseline signal, REBS), on CH4 as an auxiliary tracer (AUX), and on meteorological parameters (MET). All approaches do suitably well to capture the seasonal CO2 cycle at LAN. Differences are observed in the average regional mole fractions with annual values in the REBS method at least 1.7 ± 0.2 ppm higher than the other methods. The BC method may underestimate the regional CO2 mole fractions during the winter-spring period and should be treated with caution. The REBS method is a purely statistical method and it may also introduce errors on the regional CO2 mole fraction evaluations, as the filtered trend may be influenced by the "noisy" raw data series. Although there are correlations between CH4 and CO2 mole fractions at LAN, the different source/sink regimes may introduce bias on the regional CO2 estimation in the AUX method, typically in summer. Overall, the MET method seems to be the most favorable because it mainly focuses on the influence of potential local sources and sinks, and considers diurnal variations and meteorological conditions. Using the MET method, the annual growth rate of regional CO2 at LAN is determined to be 3.1 ± 0.01 ppm yr-1 (standard error) from 2009 to 2011.

  17. Comparison of surface energy fluxes with satellite-derived surface energy flux estimates from a shrub-steppe

    Energy Technology Data Exchange (ETDEWEB)

    Kirkham, Randy R. [Univ. of Washington, Seattle, WA (United States)

    1993-12-01

    This thesis relates the components of the surface energy balance (i.e., net radiation, sensible and latent heat flux densities, soil heat flow) to remotely sensed data for native vegetation in a semi-arid environment. Thematic mapper data from Landsat 4 and 5 were used to estimate net radiation, sensible heat flux (H), and vegetation amount. Several sources of ground truth were employed. They included soil water balance using the neutron thermalization method and weighing lysimeters, and the measurement of energy fluxes with the Bowen ratio energy balance (BREB) technique. Sensible and latent heat flux were measured at four sites on the U.S. Department of Energy`s Hanford Site using a weighing lysimeter and/or BREB stations. The objective was to calibrate an aerodynamic transport equation that related H to radiant surface temperature. The transport equation was then used with Landsat thermal data to generate estimates of H and compare these estimates against H values obtained with BREB/lysimeters at the time of overflight. Landsat and surface meteorologic data were used to estimate the radiation budget terms at the surface. Landsat estimates of short-wave radiation reflected from the surface correlate well with reflected radiation measured using inverted Eppley pyranometers. Correlation of net radiation estimates determined from satellite data, pyranometer, air temperature, and vapor pressure compared to net radiometer values obtained at time of overflight were excellent for a single image, but decrease for multiple images. Soil heat flux, GT, is a major component of the energy balance in arid systems and G{sub T} generally decreases as vegetation cover increases. Normalized difference vegetation index (NDVI) values generated from Landsat thermatic mapper data were representative of field observations of the presence of green vegetation, but it was not possible to determine a single relationship between NDVI and GT for all sites.

  18. SUPPLEMENTARY COMPARISON - EUROMET.L-S11 comparison on surface texture

    DEFF Research Database (Denmark)

    Koenders, L.; Andreasen, Jan Lasson; De Chiffre, Leonardo

    2004-01-01

    The measurement of roughness of technical surfaces is important in research and for industry. There are a lot of 2D roughness parameters that are defined and standardized by ISO. Calibration standards can be used to calibrate the instruments and ensure traceability to the SI unit of length. Most ...

  19. Vertical profiles of aerosol optical properties over central Illinois and comparison with surface and satellite measurements

    Directory of Open Access Journals (Sweden)

    P. J. Sheridan

    2012-12-01

    Full Text Available Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1 measure the in situ aerosol properties and determine their vertical and temporal variability and (2 relate these aircraft measurements to concurrent surface and satellite measurements. The primary profile location was within 15 km of the NOAA/ESRL surface aerosol monitoring station near Bondville, Illinois. Identical instruments at the surface and on the aircraft ensured that the data from both platforms would be directly comparable and permitted a determination of how representative surface aerosol properties were of the lower column. Aircraft profiles were also conducted occasionally at two other nearby locations to increase the frequency of A-Train satellite underflights for the purpose of comparing in situ and satellite-retrieved aerosol data. Measurements of aerosol properties conducted at low relative humidity over the Bondville site compare well with the analogous surface aerosol data and do not indicate any major sampling issues or that the aerosol is radically different at the surface compared with the lowest flyby altitude of ~ 240 m above ground level. Statistical analyses of the in situ vertical profile data indicate that aerosol light scattering and absorption (related to aerosol amount decreases substantially with increasing altitude. Parameters related to the nature of the aerosol (e.g., single-scattering albedo, Ångström exponent, etc., however, are relatively constant throughout the mixed layer, and do not vary as much as the aerosol amount throughout the profile. While individual profiles often showed more variability, the median in situ single-scattering albedo was 0.93–0.95 for all sampled altitudes. Several parameters (e.g., submicrometer scattering fraction, hemispheric backscattering fraction, and

  20. Comparison of glass surfaces as a countertop material to existing surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Turo, Laura A.; Winschell, Abigail E.

    2011-09-01

    Gleen Glass, a small production glass company that creates countertops, was selected for the Technology Assistance Program through Pacific Northwest National Laboratory. Gleen Glass was seeking material property analysis comparing glass as a countertop material to current surfaces (i.e. marble, granite and engineered stone). With samples provided from Gleen Glass, testing was done on granite, marble, and 3 different glass surfaces ('Journey,' 'Pebble,' and 'Gleen'). Results showed the glass surfaces have a lower density, lower water absorption, and are stronger in compressive and flexural tests as compared to granite and marble. Thermal shock tests showed the glass failed when objects with a high thermal mass are placed directly on them, whereas marble and granite did not fracture under these conditions.

  1. Comparison of solutions of a problem of Cauchy-Poisson type under discontinuous and smooth initial values with the marigrams of Tsunami 2011 obtained from DART stations

    Science.gov (United States)

    Sekerzh-Zen'kovich, S. Ya.

    2016-10-01

    The problem of Cauchy-Poisson type is considered in the framework of potential tsunami model with impulse cylindical compactly supported source discontinuous with respect to the radial horizontal coordinate under the assumption that the depth of the liquid is constant. An analytical solution of the problem for a special choice of values of the parameters of the source is given. The connection the solution thus obtained with nonstandard characteristics introduced by Maslov is discussed. The graphs of the time history of the free surface elevation are compared with the marigrams, received for the 2011 tsunami from the DART stations 21418, 21413, and 51407, and also with graphs calculated for the well-known model with a "simple" source.

  2. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    Science.gov (United States)

    Franco, B.; Hendrick, F.; Van Roozendael, M.; Müller, J.-F.; Stavrakou, T.; Marais, E. A.; Bovy, B.; Bader, W.; Fayt, C.; Hermans, C.; Lejeune, B.; Pinardi, G.; Servais, C.; Mahieu, E.

    2015-04-01

    As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010-December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6-8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation.

  3. Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

    Directory of Open Access Journals (Sweden)

    B. Franco

    2015-04-01

    Full Text Available As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs, formaldehyde (HCHO plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS scans recorded during the July 2010–December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.. Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs, GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6–8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation.

  4. Comparison of the Standards applied to Instrumentation and Control Systems for Nuclear Power Stations in Korea and Russia

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hyun; Hwang, In Koo; Lee, Dong Young

    2005-04-15

    This report describes a comparison result of technical standards applied to instrumentation and control systems for nuclear power plants between in Korea and in Russia. Russia also has a state-run organization authorized to conduct approval, cancellation, and audit in use of nuclear facility or equipment. The Russian standards for nuclear instrumentation and control equipment are analogous with the Korean ones in the aspect of basic concepts and principles. However, there are some differences in document structure, design requirements, qualification test items, depth of contents between two standard systems. The biggest deviation exists in the standard documents for seismic qualification and electromagnetic interference qualification. Korean seismic qualification standard utilizing US approach, defines testing and qualification methods specifically and clearly. Russian standards however provide only conceptual definitions and requirements in the seismic related aspects. Therefore, it is conceived that any equipment or system qualified seismically in accordance with Korean standards should additionally provide technical evidence that it is satisfactory with Russian standards as well. In electromagnetic interference qualification, because Russian standard requires more testing items than the current Korean standard, the additional qualification tests are necessary to meet the Russian requirements. However, these additional test items are based on IEC(International Electrotechnical Commission), therefore it is not a problem to perform those tests in a Korean testing facility.

  5. Photoelectron emission from plasmonic nanoparticles: Comparison between surface and volume photoelectric effects

    CERN Document Server

    Uskov, Alexander V; Ikhsanov, Renat Sh; Babicheva, Viktoriia E; Zhukovsky, Sergei V; Lavrinenko, Andrey V; OReilly, Eoin P; Xu, Hongxing

    2013-01-01

    We study emission of photoelectrons from plasmonic nanoparticles into surrounding matrix. We consider two mechanisms of the photoelectric effect from nanoparticles - surface and volume ones, and use models of these two effects which allow us to obtain analytical results for the photoelectron emission rates from nanoparticle. Calculations have been done for the step potential at surface of spherical nanoparticle, and the simple model for the hot electron cooling have been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary in the surface mechanism, which leads to substantial (by 5 times) increase of photoelectron emission rate from nanoparticle compared to the case when such discontinuity is absent. For plasmonic nanoparticle, a comparison of two mechanisms of the photoeffect was done for the first time and showed that surface photoeffect, at least, does not concede the volume one, which agrees with results for the flat metal surface first formulated b...

  6. Cross validation of geotechnical and geophysical site characterization methods: near surface data from selected accelerometric stations in Crete (Greece)

    Science.gov (United States)

    Loupasakis, C.; Tsangaratos, P.; Rozos, D.; Rondoyianni, Th.; Vafidis, A.; Kritikakis, G.; Steiakakis, M.; Agioutantis, Z.; Savvaidis, A.; Soupios, P.; Papadopoulos, I.; Papadopoulos, N.; Sarris, A.; Mangriotis, M.-D.; Dikmen, U.

    2015-06-01

    The specification of the near surface ground conditions is highly important for the design of civil constructions. These conditions determine primarily the ability of the foundation formations to bear loads, the stress - strain relations and the corresponding settlements, as well as the soil amplification and corresponding peak ground motion in case of dynamic loading. The static and dynamic geotechnical parameters as well as the ground-type/soil-category can be determined by combining geotechnical and geophysical methods, such as engineering geological surface mapping, geotechnical drilling, in situ and laboratory testing and geophysical investigations. The above mentioned methods were combined, through the Thalis ″Geo-Characterization″ project, for the site characterization in selected sites of the Hellenic Accelerometric Network (HAN) in the area of Crete Island. The combination of the geotechnical and geophysical methods in thirteen (13) sites provided sufficient information about their limitations, setting up the minimum tests requirements in relation to the type of the geological formations. The reduced accuracy of the surface mapping in urban sites, the uncertainties introduced by the geophysical survey in sites with complex geology and the 1D data provided by the geotechnical drills are some of the causes affecting the right order and the quantity of the necessary investigation methods. Through this study the gradual improvement on the accuracy of site characterization data is going to be presented by providing characteristic examples from a total number of thirteen sites. Selected examples present sufficiently the ability, the limitations and the right order of the investigation methods.

  7. Studying the effectiveness of using pneumoimpulsive technology for cleaning the platen surfaces of the PK-38 boiler at the Nazarovo district power station

    Science.gov (United States)

    Agliulin, S. G.; Nikolaev, S. F.; Zvegintsev, V. I.; Yurkin, I. A.; Shabanov, I. I.; Palkin, V. F.; Sergienko, S. P.; Vlasov, S. M.

    2014-09-01

    A new pneumoimpulsive technology, central to which is an impact effect of air jet on ash deposits, was proposed for carrying out continuous preventive cleaning of the platens installed in the steam superheater primary and secondary paths of the PK-38 boiler at the Nazarovo district power station. The pneumoimpulsive cleaning system was mounted in the PK-38 boiler unit no. 6A, and the cleaning system tests were carried out during field operation of the boiler. Owing to the use of the proposed cleaning system, long-term (for no less than 3 months of observations) slag-free operation of the platen surfaces was achieved in the range of steam loads from 215 to 235 t/h with the average load equal to 225 t/h at furnace gas temperatures upstream of the platens equal to 1220-1250°C.

  8. [Comparison of performances in retrieving impervious surface between hyperspectral (Hyperion) and multispectral (TM/ETM+) images].

    Science.gov (United States)

    Tang, Fei; Xu, Han-Qiu

    2014-04-01

    The retrieval of impervious surface is a hot topic in the remote sensing field in the past decade. Nevertheless, studies on retrieving impervious surface from hyperspectral image and the comparison of the performances in retrieving impervious surface between hyperspectral and multispectral images are rarely reported. Therefore, The present paper focuses on the characteristics of hyperspectral (EO-1 Hyperion) and multispectral (Landsat TM/ETM+) images and implements a complementary study on the comparison based on the retrieved impervious surface information between Hyperion and TM/ETM+ data. For up to 242 bands of Hyperion image, a further study was carried out to select feature bands for impervious surface retrieving using stepwise discriminant analysis. As a result, 11 feature bands were selected and a new image named Hyperion' was thus composed. The new Hyperion' image was used to investigate whether this band-reduced image could obtain higher accuracy in retrieving impervious surface. The three test regions were selected from Fuzhou, Guangzhou and Hangzhou of China, with date-coincident or nearly coincident image pairs of the used sensors. The linear spectral mixture analysis (LSMA) was employed to retrieve impervious surface and the results were accessed for their accuracy. The comparison shows that the Hyperion image has higher accuracy than TM/ETM+, and the Hyperion' composed of the selected 11 feature bands has the highest accuracy. The advantages of Hyperion in spectral and radiometric resolutions over TM/ETM+ are believed to be the main factors contributing to the higher accuracy. The high spectral and radiometric resolutions of Hyperion image allow the sensor to have higher sensitivity in distinguishing subtle spectral changes of ground objects. While, the highest accuracy the 11-band Hyperion' image achieved is owing to the significant reduction of the band dimension of the image and thus the band redundancy.

  9. Examination of Surface Residuals Obtained During Re-Lubrication of the International Space Station (ISS) Solar Alpha Rotary Joint (SARJ)

    Science.gov (United States)

    Martinez, J. E.; Golden, J. L.

    2012-01-01

    The starboard SARJ mechanism on the ISS suffered a premature lubrication failure, resulting in widespread loss of the nitride case layer on its 10.3 meter circumference, 15-5PH steel race ring [1, 2]. To restore functionality, vacuum-stable grease was applied on-orbit, first to the port SARJ mechanism to save it from the damage suffered by the starboard mechanism. After 3 years of greased operation, telemetry indicated that the port mechanism required relubrication, so part of that process included sampling each of the three race ring surfaces to evaluate any wear debris recovered and the state of the originally applied grease. Extensive microscopic examination was conducted, which directed subsequent microanalysis of particulate. Since the SARJ mechanism operates in the vacuum of space, a sampling method and tool had to be developed for use by astronauts while working in the extravehicular mobility unit (EMU). The sampling tool developed was a cotton terry-cloth mitt for the EMU glove, with samples taken by swiping each of the three port SARJ race-ring surfaces. The sample mitts for each surface were folded inward after sampling to preserve sample integrity, for return and ground analysis. The sample mitt for what is termed the outer canted surface of the SARJ race-ring is shown in Figure 1. Figure 1 also demonstrates how increasing levels of magnification were used to survey the contamination removed in sampling, specifically looking for signs of wear debris or other features which could be further evaluated using Scanning Electron Microscopy (SEM) methods. The most surprising overall result at this point in the analysis was the relatively small amounts of grease recovered during sampling. It is clear that the mechanism was not operating with surplus lubricant. Obviously, evidence of molybdenum disulfide (MoS2), a major component in the grease applied, was prevalent in the analysis conducted. But a small amount of mechanism wear debris was observed. Figure 2

  10. Comparison of Relative Humidity obtained from SAPHIR on board Megha-Tropiques and Ground based Microwave Radiometer Profiler over an equatorial station

    Science.gov (United States)

    Renju, Ramachandran Pillai; Uma, K. N.; Krishna Moorthy, K.; Mathew, Nizy; Raju C, Suresh

    A comparison has been made between the SAPHIR on board Megha-Tropiques (MT) derived Relative Humidity (RH (%)) with that derived from a ground based multi-frequency Microwave Radiometer Profiler (MRP) observations over an equatorial station Thiruvananthapuram (8.5(°) N and 76.9(°) E) for a one year period. As a first step, the validation of MRP has been made against the radiosonde for two years (2010 and 2011) during the Indian monsoon period July-September. This analysis shows a wet bias below 6 km and dry bias above. The comparison between the MRP and the MT derived RH has been made at five different altitudinal levels (0.75, 2.25, 4.0, 6.25 and 9.2 km range) strictly under clear sky condition. The regression analysis between the two reveals very good correlation (>0.8) in the altitudinal layer of 2.25 to 6.25 km. The differences between the two observations had also been explained interms of percentage of occurrence between MT and the MRP at each altitudinal layer. About 70-80% of the time, the difference in the RH is found to below 10% at first three layer. The RMSE of 2% is observed at almost all the height layers. The differences have been attributed to the different measurement and retrieval techniques involved in the ground based and satellite based measurements. Since MRP frequecy channels are not sensitive to small water vapor variabilities above 6 km, large differences are observed. Radiative Transfer computation for the channels of both MRP and SAPHIR will be carried out to understand the variabilities.

  11. Mean sea surface and geoid gradient comparisons with TOPEX altimeter data

    Science.gov (United States)

    Rapp, Richard H.; Yi, Yuchan; Wang, Yan Ming

    1994-01-01

    Cycles 4 to 54 of TOPEX data have been analyzed through comparisons with the mean sea surface given on the disturbed geophysical data record (GDR). Two inverted barometer correction procedures were considered for the data reduction. One used a constant atmospheric pressure for all data while the one adopted for use, for most computations, introduced a cycle average pressure. The maximum difference between the two estimates was 3.0 cm with a clear annual signal. With the modified correction the TOPEX sea surface was compared to The Ohio State University (OSU) mean sea surface, given on the GDR, to estimate three translations ( delta x = -2.3 cm; delta y = 25.0 cm; delta z = -0.3 cm) and a bias (43.3 cm) between the two surfaces. The only significant translation is delta y which indicates the reference frame of the TOPEX system differs from that used in the OSU mean sea surface system. The bias between the TOPEX mean sea surface and the OSU mean sea surface was used to estimate an equatorial radius of 6,378,136.55 m based on an 18-cm biased estimate of the TOPEX altimeter. Examination of the average difference, by cycle, between the TOPEX sea surface and the OSU mean sea surface suggested a bias change of 3.1 +/- 2.2 mm/yr with a positive sign indicating the average ocean surface is rising or the altimeter measured distance is decreasing. Models were implemented that solved directly for a bias, bias rate annual/semiannual, and tide correction terms. The computations indicated that a simultaneous solution for this bias, bias rate, and annual/semiannual terms gave the most accurate results. Nonsimultaneous solutions led to slightly different bias rate values. The root mean square difference between the TOPEX sea surface and OSU sea surface, after translation and bias correction, was +/- 17 cm for a typical cycle. Some locations were indentified where the difference could reach 2.3 cm and were repeated over several cycles indicating errors in the mean sea surface. Most

  12. Comparison of Hourly Solar Radiation from a Ground–Based Station, Remote Sensing and Weather Forecast Models at a Coastal Site of South Italy (Lamezia Terme)

    DEFF Research Database (Denmark)

    Feudo, Teresa Lo; Avolio, Elenio; Gullì, Daniel;

    2015-01-01

    The solar radiation is a critical input parameter when working with solar energy and radiation dependent surface processes. In this study, we present preliminary results from an inter-comparison between hourly values from a pyranometer, MSG-SEVIRI sensor and two meso-scale models, WRF and RAMS......, in clear and cloudy sky conditions. Cloudy sky condition is the most important because the attenuation of solar radiation in the atmosphere is strongly dependent on the cloud variability. Bias and RMSE errors are evaluated at a coastal site in the Mediterranean area. These statistics show the tendency...... of both models to overestimate short-wave radiation....

  13. The influence of wind speed on surface layer stability and turbulent fluxes over southern Indian peninsula station

    Indian Academy of Sciences (India)

    M N Patil; R T Waghmare; T Dharmaraj; G R Chinthalu; Devendraa Siingh; G S Meena

    2016-10-01

    Surface to atmosphere exchange has received much attention in numerical weather prediction models. This exchange is defined by turbulent parameters such as frictional velocity, drag coefficient and heat fluxes, which have to be derived experimentally from high-frequency observations. High-frequency measurementsof wind speed, air temperature and water vapour mixing ratio (eddy covariance measurements), were made during the Integrated Ground Observation Campaign (IGOC) of Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) at Mahabubnagar, India (16◦44'N, 77◦59'E) in the south-west monsoon season. Using these observations, an attempt was made to investigatethe behaviour of the turbulent parameters, mentioned above, with respect to wind speed. We found that the surface layer stability derived from the Monin–Obukhov length scale, is well depicted by the magnitude of wind speed, i.e., the atmospheric boundary layer was under unstable regime for wind speeds greater than 4 m s−1; under stable regime for wind speeds less than 2 m s−1 and under neutral regime for wind speeds in the range of 2–3 m s$^{−1}$. All the three stability regimes were mixed for wind speeds 3–4 m s$^{−1}$. The drag coefficient shows scatter variation with wind speed in stable as well as unstable conditions.

  14. The influence of wind speed on surface layer stability and turbulent fluxes over southern Indian peninsula station

    Science.gov (United States)

    Patil, M. N.; Waghmare, R. T.; Dharmaraj, T.; Chinthalu, G. R.; Siingh, Devendraa; Meena, G. S.

    2016-09-01

    Surface to atmosphere exchange has received much attention in numerical weather prediction models. This exchange is defined by turbulent parameters such as frictional velocity, drag coefficient and heat fluxes, which have to be derived experimentally from high-frequency observations. High-frequency measurements of wind speed, air temperature and water vapour mixing ratio (eddy covariance measurements), were made during the Integrated Ground Observation Campaign (IGOC) of Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) at Mahabubnagar, India (16∘44'N, 77∘59'E) in the south-west monsoon season. Using these observations, an attempt was made to investigate the behaviour of the turbulent parameters, mentioned above, with respect to wind speed. We found that the surface layer stability derived from the Monin-Obukhov length scale, is well depicted by the magnitude of wind speed, i.e., the atmospheric boundary layer was under unstable regime for wind speeds >4 m s-1; under stable regime for wind speeds <2 m s-1 and under neutral regime for wind speeds in the range of 2-3 m s-1. All the three stability regimes were mixed for wind speeds 3-4 m s-1. The drag coefficient shows scatter variation with wind speed in stable as well as unstable conditions.

  15. A comparison of Argo nominal surface and near-surface temperature for validation of AMSR-E SST

    Science.gov (United States)

    Liu, Zenghong; Chen, Xingrong; Sun, Chaohui; Wu, Xiaofen; Lu, Shaolei

    2017-05-01

    Satellite SST (sea surface temperature) from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) is compared with in situ temperature observations from Argo profiling floats over the global oceans to evaluate the advantages of Argo NST (near-surface temperature: water temperature less than 1 m from the surface). By comparing Argo nominal surface temperature ( 5 m) with its NST, a diurnal cycle caused by daytime warming and nighttime cooling was found, along with a maximum warming of 0.08±0.36°C during 14:00-15:00 local time. Further comparisons between Argo 5-m temperature/Argo NST and AMSR-E SST retrievals related to wind speed, columnar water vapor, and columnar cloud water indicate warming biases at low wind speed (28 mm during daytime. The warming tendency is more remarkable for AMSR-E SST/Argo 5-m temperature compared with AMSR-E SST/Argo NST, owing to the effect of diurnal warming. This effect of diurnal warming events should be excluded before validation for microwave SST retrievals. Both AMSR-E nighttime SST/Argo 5-m temperature and nighttime SST/Argo NST show generally good agreement, independent of wind speed and columnar water vapor. From our analysis, Argo NST data demonstrated their advantages for validation of satellite-retrieved SST.

  16. Comparison of Martian Surface Radiation Predictions to the Measurements of Mars Science Laboratory Radiation Assessment Detector (MSL/RAD)

    Science.gov (United States)

    Kim, Myung-Hee Y.; Cucinotta, Francis A.; Zeitlin, Cary; Hassler, Donald M.; Ehresmann, Bent; Rafkin, Scot C. R.; Wimmer-Schweingruber, Robert F; Boettcher, Stephan; Boehm, Eckart; Guo, Jingnan; hide

    2014-01-01

    For the analysis of radiation risks to astronauts and planning exploratory space missions, detailed knowledge of particle spectra is an important factor. Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Mars Science Laboratory Radiation Assessment Detector (MSL-RAD) on the Curiosity rover since August 2012, and particle fluxes for a wide range of ion species (up to several hundred MeV/u) and high energy neutrons (8 - 1000 MeV) have been available for the first 200 sols. Although the data obtained on the surface of Mars for 200 sols are limited in the narrow energy spectra, the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code are compared to the data. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used, which includes direct knockout, evaporation and nuclear coalescence. Daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station are implemented into transport calculations for describing the daily column depth of atmosphere. Particles impinging on top of the Martian atmosphere reach the RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD by the rest of the instrument. Calculations of stopping particle spectra are in good agreement with the RAD measurements for the first 200 sols by accounting changing heliospheric conditions and atmospheric pressure. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and thus increase the accuracy of the predictions of future radiation environments on Mars. These contributions lend support to the understanding of radiation health risks to

  17. Comparison of near surface and column-integrated atmospheric aerosol optical properties

    Science.gov (United States)

    Aryal, Rudra Prasad

    Optical and chemical properties of size-resolved aerosols in near-surface air at Tudor Hill, Bermuda were measured between July 2006 and June 2009. Vertical distributions of aerosol backscattering and column-averaged aerosol optical properties were characterized with a Micro-pulse lidar (MPL) and a CIMEL automated sun-sky radiometer. The chemical species in size-segregated aerosols in marine air were compared with the surface level aerosol optical properties. The aerosol concentration, along with chemical components, was compared with the surface level wind speed and showed a significant correlation with the sea salt components. The non-sea salt components such as non-sea salt sulfate and ammonium did not show a correlation with the surface level wind speed. A comparison between scattering data at surface level with the extinction coefficient at the lowest altitude bin (75m) from the lidar inversion shows a consistent correlation but is quantitatively different. This quantitative discrepancy was explained based on the hygroscopic growth due to differences in relative humidity in measurement conditions. Aerosol optical properties measured near the surface were often significantly correlated with those averaged over the column. These include scattering by near-surface bulk aerosol at 530 nm versus column aerosol optical depth (AOD), near-surface sub-microm scattering fraction versus column averaged sub-microm scattering fraction, and the average angstrom exponent over column and lidar ratio derived using column integrated size distribution and complex refractive index. We also found that the single scattering albedo (ω o) measured at the surface by combining daily averages of the aerosol absorption and aerosol light scattering were in the same range as the instantaneous ω o retrieved for the column. The relative contribution of submicron aerosol light scattering to total aerosol light scattering is slightly higher in the column relative to the surface. Surface

  18. Comparison of satellite-derived land surface temperature and air temperature from meteorological stations on the Pan-Arctic scale

    NARCIS (Netherlands)

    Urban, M.; Eberle, J.; Hüttich, C.; Schmullius, C.; Herold, M.

    2013-01-01

    Satellite-based temperature measurements are an important indicator for global climate change studies over large areas. Records from Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Very High Resolution Radiometer (AVHRR) and (Advanced) Along Track Scanning Radiometer ((A)ATSR) are pr

  19. A Comparison Between Jerusalem Cross and Square Patch Frequency Selective Surfaces for Low Profile Antenna Applications

    Science.gov (United States)

    Cure, David; Weller, Thomas; Miranda, Felix A.

    2011-01-01

    In this paper, a comparison between Jerusalem Cross (JC) and Square Patch (SP) based Frequency Selected Surfaces (FSS) for low profile antenna applications is presented. The comparison is aimed at understanding the performance of low profile antennas backed by high impedance surfaces. In particular, an end loaded planar open sleeve dipole (ELPOSD) antenna is examined due to the various parameters within its configuration, offering significant design flexibility and a wide operating bandwidth. Measured data of the antennas demonstrate that increasing the number of unit cells improves the fractional bandwidth. The antenna bandwidth increased from 0.8% to 1.8% and from 0.8% to 2.7% for the JC and SP structures, respectively. The number of unit cells was increased from 48 to 80 for the JC-FSS and from 24 to 48 for the SP-FSS.

  20. Quantitative comparison of a human cancer cell surface proteome between interphase and mitosis.

    Science.gov (United States)

    Özlü, Nurhan; Qureshi, Mohammad H; Toyoda, Yusuke; Renard, Bernhard Y; Mollaoglu, Gürkan; Özkan, Nazlı E; Bulbul, Selda; Poser, Ina; Timm, Wiebke; Hyman, Anthony A; Mitchison, Timothy J; Steen, Judith A

    2015-01-13

    The cell surface is the cellular compartment responsible for communication with the environment. The interior of mammalian cells undergoes dramatic reorganization when cells enter mitosis. These changes are triggered by activation of the CDK1 kinase and have been studied extensively. In contrast, very little is known of the cell surface changes during cell division. We undertook a quantitative proteomic comparison of cell surface-exposed proteins in human cancer cells that were tightly synchronized in mitosis or interphase. Six hundred and twenty-eight surface and surface-associated proteins in HeLa cells were identified; of these, 27 were significantly enriched at the cell surface in mitosis and 37 in interphase. Using imaging techniques, we confirmed the mitosis-selective cell surface localization of protocadherin PCDH7, a member of a family with anti-adhesive roles in embryos. We show that PCDH7 is required for development of full mitotic rounding pressure at the onset of mitosis. Our analysis provided basic information on how cell cycle progression affects the cell surface. It also provides potential pharmacodynamic biomarkers for anti-mitotic cancer chemotherapy.

  1. Surface behavior of amphiphiles in aqueous solution: a comparison between different pentanol isomers.

    Science.gov (United States)

    Walz, M-M; Caleman, C; Werner, J; Ekholm, V; Lundberg, D; Prisle, N L; Öhrwall, G; Björneholm, O

    2015-06-07

    Position isomerism is ubiquitous in atmospheric oxidation reactions. Therefore, we have compared surface-active oxygenated amphiphilic isomers (1- and 3-pentanol) at the aqueous surface with surface- and chemically sensitive X-ray photoelectron spectroscopy (XPS), which reveals information about the surface structure on a molecular level. The experimental data are complemented with molecular dynamics (MD) simulations. A concentration-dependent orientation and solvation of the amphiphiles at the aqueous surface is observed. At bulk concentrations as low as around 100 mM, a monolayer starts to form for both isomers, with the hydroxyl groups pointing towards the bulk water and the alkyl chains pointing towards the vacuum. The monolayer (ML) packing density of 3-pentanol is approx. 70% of the one observed for 1-pentanol, with a molar surface concentration that is approx. 90 times higher than the bulk concentration for both molecules. The molecular area at ML coverage (≈100 mM) was calculated to be around 32 ± 2 Å(2) per molecule for 1-pentanol and around 46 ± 2 Å(2) per molecule for 3-pentanol, which results in a higher surface concentration (molecules per cm(2)) for the linear isomer. In general we conclude therefore that isomers - with comparable surface activities - that have smaller molecular areas will be more abundant at the interface in comparison to isomers with larger molecular areas, which might be of crucial importance for the understanding of key properties of aerosols, such as evaporation and uptake capabilities as well as their reactivity.

  2. Second IRMF comparison of surface contamination monitor calibrations 2001-2002

    CERN Document Server

    Scott, C J

    2002-01-01

    The Ionising Radiations Metrology Forum (IRMF) organised a second comparison of surface contamination monitor calibrations in which twenty establishments in the UK participated. The exercise involved the circulation of three surface contamination monitors for calibration using large area reference sources available in the participants' laboratories. The instruments used were a Mini Instruments EP15, a Berthold LB122 and an Electra ratemeter with DP6AD probe. The instrument responses were calculated by the individual participants and submitted to the for analysis along with details of the reference sources used. Details of the estimated uncertainties were also reported. The results are compared and demonstrate generally satisfactory agreement between the participating establishments.

  3. Comparison of mechanical properties of surface layers with use of nanoindentation and microindentation tests

    Directory of Open Access Journals (Sweden)

    M. Zeleňák

    2012-07-01

    Full Text Available The objective of the paper is a mutual comparison of different methods for evaluation of mechanical properties of surface layers. Mechanical properties were tested with the use of nanoindentation and microindentation tests. Different loads and constant deformation speed were used in both cases. For the evaluation of mechanical properties, the AISI 304 type Chromium-Nickel steel commonly used in mechanical engineering industry was tested. Knowledge of relations and differences between nano and micromechanical properties is necessary for understanding of mechanical processes continuously occurring in surface layers during cutting processes.

  4. Comparison of connective tissue graft and guided tissue regeneration in covering root surfaces

    OpenAIRE

    LotfazarM.; Faghihi Sh.

    2002-01-01

    There are many researches evaluation different methods for covering the root surface. In the most of these studies, type I and II of Miller treatment had been searched. The purpose of this study was a comparison between connective tissue graft (CTG) and guided tissue regeneration (GTR) with a collagen membrane in the treatment of gingival recession defects (Miller class III). Six patients, each contributing a pair of Miller class III buccal gingival recessions, were treated. The clinical meas...

  5. Comparison of Sensible Heat Flux from Eddy Covariance and Scintillometer over different land surface conditions

    Science.gov (United States)

    Zeweldi, D. A.; Gebremichael, M.; Summis, T.; Wang, J.; Miller, D.

    2008-12-01

    The large source of uncertainty in satellite-based evapotranspiration algorithm results from the estimation of sensible heat flux H. Traditionally eddy covariance sensors, and recently large-aperture scintillometers, have been used as ground truth to evaluate satellite-based H estimates. The two methods rely on different physical measurement principles, and represent different foot print sizes. In New Mexico, we conducted a field campaign during summer 2008 to compare H estimates obtained from the eddy covariance and scintillometer methods. During this field campaign, we installed sonic anemometers; one propeller eddy covariance (OPEC) equipped with net radiometer and soil heat flux sensors; large aperture scintillometer (LAS); and weather station consisting of wind speed, direction and radiation sensors over three different experimental areas consisting of different roughness conditions (desert, irrigated area and lake). Our results show the similarities and differences in H estimates obtained from these various methods over the different land surface conditions. Further, our results show that the H estimates obtained from the LAS agree with those obtained from the eddy covariance method when high frequency thermocouple temperature, instead of the typical weather station temperature measurements, is used in the LAS analysis.

  6. Patterns of Avian Migration in California: An Analysis and Comparison of Results from NEXRAD Doppler Weather Radar and Multiple Mist-net Stations

    Science.gov (United States)

    2008-02-01

    KMAX Medford, OR KBHX Eureka, CA KRGX Nixon, NV KBBX Sacramento, CA KDAX Davis, CA KMUX Los Gatos , CA KHNX Hanford, CA KESX Las Vegas, NV...The stations at Medford, OR (KMAX) and Los Gatos , CA (KMUX) both had the highest number of high-level migration densities (3 nights...additionally the Los Gatos station also detected the highest number of medium-level migration densities (26 nights). The Nixon, NV (KRXG) station

  7. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms.

  8. Comparison of time-dependent changes in the surface hardness of different composite resins

    Science.gov (United States)

    Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

    2013-01-01

    Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey's test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P < 0.05). The lowest was obtained with Filtek Silorane. The hardness values of all test groups increased after 24 h (P < 0.05). Conclusion: Although silorane-based composite resin Filtek Silorane showed adequate hardness ratio, the use of incremental technic during application is more important than methacrylate based composites. PMID:24966724

  9. Observation Station

    Science.gov (United States)

    Rutherford, Heather

    2011-01-01

    This article describes how a teacher integrates science observations into the writing center. At the observation station, students explore new items with a science theme and use their notes and questions for class writings every day. Students are exposed to a variety of different topics and motivated to write in different styles all while…

  10. Long-term trends of surface ozone and its influencing factors at the Mt Waliguan GAW station, China - Part 1: Overall trends and characteristics

    Science.gov (United States)

    Xu, Wanyun; Lin, Weili; Xu, Xiaobin; Tang, Jie; Huang, Jianqing; Wu, Hao; Zhang, Xiaochun

    2016-05-01

    Tropospheric ozone is an important atmospheric oxidant, greenhouse gas and atmospheric pollutant at the same time. The oxidation capacity of the atmosphere, climate, human and vegetation health can be impacted by the increase of the ozone level. Therefore, long-term determination of trends of baseline ozone is highly needed information for environmental and climate change assessment. So far, studies on the long-term trends of ozone at representative sites are mainly available for European and North American sites. Similar studies are lacking for China and many other developing countries. Measurements of surface ozone were carried out at a baseline Global Atmospheric Watch (GAW) station in the north-eastern Tibetan Plateau region (Mt Waliguan, 36°17' N, 100°54' E, 3816 m a.s.l.) for the period of 1994 to 2013. To uncover the variation characteristics, long-term trends and influencing factors of surface ozone at this remote site in western China, a two-part study has been carried out, with this part focusing on the overall characteristics of diurnal, seasonal and long-term variations and the trends of surface ozone. To obtain reliable ozone trends, we performed the Mann-Kendall trend test and the Hilbert-Huang transform (HHT) analysis on the ozone data. Our results confirm that the mountain-valley breeze plays an important role in the diurnal cycle of surface ozone at Waliguan, resulting in higher ozone values during the night and lower ones during the day, as was previously reported. Systematic diurnal and seasonal variations were found in mountain-valley breezes at the site, which were used in defining season-dependent daytime and nighttime periods for trend calculations. Significant positive trends in surface ozone were detected for both daytime (0.24 ± 0.16 ppbv year-1) and nighttime (0.28 ± 0.17 ppbv year-1). The largest nighttime increasing rate occurred in autumn (0.29 ± 0.11 ppbv year-1), followed by spring (0.24 ± 0.12 ppbv year-1), summer (0.22 ± 0

  11. Relationship between Surface Urban Heat Island intensity and sensible heat flux retrieved from meteorological parameters observed by road weather stations in urban area

    Science.gov (United States)

    Gawuć, Lech

    2017-04-01

    Urban Heat Island (UHI) is a direct consequence of altered energy balance in urban areas (Oke 1982). There has been a significant effort put into an understanding of air temperature variability in urban areas and underlying mechanisms (Arnfield 2003, Grimmond 2006, Stewart 2011, Barlow 2014). However, studies that are concerned on surface temperature are less frequent. Therefore, Voogt & Oke (2003) proposed term "Surface Urban Heat Island (SUHI)", which is analogical to UHI and it is defined as a difference in land surface temperature (LST) between urban and rural areas. SUHI is a phenomenon that is not only concerned with high spatial variability, but also with high temporal variability (Weng and Fu 2014). In spite of the fact that satellite remote sensing techniques give a full spatial pattern over a vast area, such measurements are strictly limited to cloudless conditions during a satellite overpass (Sobrino et al., 2012). This significantly reduces the availability and applicability of satellite LST observations, especially over areas and seasons with high cloudiness occurrence. Also, the surface temperature is influenced by synoptic conditions (e.g., wind and humidity) (Gawuc & Struzewska 2016). Hence, utilising single observations is not sufficient to obtain a full image of spatiotemporal variability of urban LST and SUHI intensity (Gawuc & Struzewska 2016). One of the possible solutions would be a utilisation of time-series of LST data, which could be useful to monitor the UHI growth of individual cities and thus, to reveal the impact of urbanisation on local climate (Tran et al., 2006). The relationship between UHI and synoptic conditions have been summarised by Arnfield (2003). However, similar analyses conducted for urban LST and SUHI are lacking. We will present analyses of the relationship between time series of remotely-sensed LST and SUHI intensity and in-situ meteorological observations collected by road weather stations network, namely: road surface

  12. Detecting local ligand-binding site similarity in nonhomologous proteins by surface patch comparison.

    Science.gov (United States)

    Sael, Lee; Kihara, Daisuke

    2012-04-01

    Functional elucidation of proteins is one of the essential tasks in biology. Function of a protein, specifically, small ligand molecules that bind to a protein, can be predicted by finding similar local surface regions in binding sites of known proteins. Here, we developed an alignment free local surface comparison method for predicting a ligand molecule which binds to a query protein. The algorithm, named Patch-Surfer, represents a binding pocket as a combination of segmented surface patches, each of which is characterized by its geometrical shape, the electrostatic potential, the hydrophobicity, and the concaveness. Representing a pocket by a set of patches is effective to absorb difference of global pocket shape while capturing local similarity of pockets. The shape and the physicochemical properties of surface patches are represented using the 3D Zernike descriptor, which is a series expansion of mathematical 3D function. Two pockets are compared using a modified weighted bipartite matching algorithm, which matches similar patches from the two pockets. Patch-Surfer was benchmarked on three datasets, which consist in total of 390 proteins that bind to one of 21 ligands. Patch-Surfer showed superior performance to existing methods including a global pocket comparison method, Pocket-Surfer, which we have previously introduced. Particularly, as intended, the accuracy showed large improvement for flexible ligand molecules, which bind to pockets in different conformations.

  13. Comparison of site effect values obtained by HVSR and HVSRN methods for single-station measurements in Tarnówek, South-Western Poland.

    Science.gov (United States)

    Mendecki, Maciej J.; Bieta, Barbara; Mateuszów, Mateusz; Suszka, Paweł

    2016-06-01

    This study compares the HVSR technique (Horizontal to Vertical Spectral Ratio), based on seismic event records, and the HVSRN technique (Horizontal to Vertical Spectral Ratio of Noise) using seismic noise registrations. Both methods allow us to study the amplification phenomenon of a horizontal component of seismic waves when the waves reach loose sediments in subsurface layers. The seismic data were measured at a three-component single seismic station located in the village of Tarnówek, in the Legnica-Głogów Copper District. The results of the study demonstrate that average HVSRN and HVSR maxima can be distinguished: for periods approximately 3.78 s (H/V = 6.2) and 3.969 s (H/V = 8.98) respectively. The evaluated share of the Rayleigh wave component in the recorded values was β = 0.58 and it can be suggested that the Love wave share in surface motion was insignificant. The Love wave share remains unknown.

  14. Comparison of site effect values obtained by HVSR and HVSRN methods for single-station measurements in Tarnówek, South-Western Poland.

    Directory of Open Access Journals (Sweden)

    Mendecki Maciej J.

    2016-06-01

    Full Text Available This study compares the HVSR technique (Horizontal to Vertical Spectral Ratio, based on seismic event records, and the HVSRN technique (Horizontal to Vertical Spectral Ratio of Noise using seismic noise registrations. Both methods allow us to study the amplification phenomenon of a horizontal component of seismic waves when the waves reach loose sediments in subsurface layers. The seismic data were measured at a three-component single seismic station located in the village of Tarnówek, in the Legnica-Głogów Copper District. The results of the study demonstrate that average HVSRN and HVSR maxima can be distinguished: for periods approximately 3.78 s (H/V = 6.2 and 3.969 s (H/V = 8.98 respectively. The evaluated share of the Rayleigh wave component in the recorded values was β = 0.58 and it can be suggested that the Love wave share in surface motion was insignificant. The Love wave share remains unknown.

  15. Using a Normalized Sobolev Norm of the Difference rather than the Difference of Sobolev Norms for Quantitative Surface Comparison

    CERN Document Server

    Perlin, Marc

    2014-01-01

    In this manuscript we present a method for the quantitative comparison of two surfaces, applicable to temporal and/or spatial extent in one or two dimensions. Often surface comparisons are simply overlaid graphs of results from different methodologies that are qualitative at best; it is the purpose of this work to facilitate quantitative evaluation. The surfaces can be analytical, numerical, and/or experimental, and the result returned by the method, termed surface similarity parameter or normalized error, has been normalized so that its value lies between zero and one. When the parameter has a value of zero, the surfaces are in perfect agreement, whereas a value of one is indicative of perfect disagreement. To provide insight regarding the magnitude of the parameter, several canonical cases are presented, followed by results from breaking water wave experimental measurements with numerical simulations, and by a comparison of a prescribed, periodic, square-wave surface profile and the subsequent manufactured ...

  16. Exhaustive comparison and classification of ligand-binding surfaces in proteins

    Science.gov (United States)

    Murakami, Yoichi; Kinoshita, Kengo; Kinjo, Akira R; Nakamura, Haruki

    2013-01-01

    Many proteins function by interacting with other small molecules (ligands). Identification of ligand-binding sites (LBS) in proteins can therefore help to infer their molecular functions. A comprehensive comparison among local structures of LBSs was previously performed, in order to understand their relationships and to classify their structural motifs. However, similar exhaustive comparison among local surfaces of LBSs (patches) has never been performed, due to computational complexity. To enhance our understanding of LBSs, it is worth performing such comparisons among patches and classifying them based on similarities of their surface configurations and electrostatic potentials. In this study, we first developed a rapid method to compare two patches. We then clustered patches corresponding to the same PDB chemical component identifier for a ligand, and selected a representative patch from each cluster. We subsequently exhaustively as compared the representative patches and clustered them using similarity score, PatSim. Finally, the resultant PatSim scores were compared with similarities of atomic structures of the LBSs and those of the ligand-binding protein sequences and functions. Consequently, we classified the patches into ∼2000 well-characterized clusters. We found that about 63% of these clusters are used in identical protein folds, although about 25% of the clusters are conserved in distantly related proteins and even in proteins with cross-fold similarity. Furthermore, we showed that patches with higher PatSim score have potential to be involved in similar biological processes. PMID:23934772

  17. Point-surface fusion of station measurements and satellite observations for mapping PM2.5 distribution in China: methods and assessment

    CERN Document Server

    Li, Tongwen; Zeng, Chao; Yuan, Qiangqiang; Zhang, Liangpei

    2016-01-01

    Fine particulate matter (PM2.5) is associated with adverse human health effects, and China is currently suffering from serious PM2.5 pollution. To obtain spatially continuous ground-level PM2.5 concentrations, several models established by point-surface fusion of ground station and satellite observations have been developed. However, how well do these models perform at national scale in China? Is there space to improve the estimation accuracy of PM2.5 concentration? The contribution of this study is threefold. Firstly, taking advantage of the newly established national monitoring network, we develop a national-scale generalized regression neural network (GRNN) model to estimate PM2.5 concentrations. Secondly, different assessment experiments are undertaken in time and space, to comprehensively evaluate and compare the performance of the widely used models. Finally, to map the yearly and seasonal mean distribution of PM2.5 concentrations in China, a pixel-based merging strategy is proposed. The results indicat...

  18. Comparison of surface wind stress measurements - Airborne radar scatterometer versus sonic anemometer

    Science.gov (United States)

    Brucks, J. T.; Leming, T. D.; Jones, W. L.

    1980-01-01

    Sea surface wind stress measurements recorded by a sonic anemometer are correlated with airborne scatterometer measurements of ocean roughness (cross section of radar backscatter) to establish the accuracy of remotely sensed data and assist in the definition of geophysical algorithms for the scatterometer sensor aboard Seasat A. Results of this investigation are as follows: Comparison of scatterometer and sonic anemometer wind stress measurements are good for the majority of cases; however, a tendency exists for scatterometer wind stress to be somewhat high for higher wind conditions experienced in this experiment (6-9 m/s). The scatterometer wind speed algorithm tends to overcompute the higher wind speeds by approximately 0.5 m/s. This is a direct result of the scatterometer overestimate of wind stress from which wind speeds are derived. Algorithmic derivations of wind speed and direction are, in most comparisons, within accuracies defined by Seasat A scatterometer sensor specifications.

  19. Internal photoemission from plasmonic nanoparticles: comparison between surface and volume photoelectric effects.

    Science.gov (United States)

    Uskov, Alexander V; Protsenko, Igor E; Ikhsanov, Renat S; Babicheva, Viktoriia E; Zhukovsky, Sergei V; Lavrinenko, Andrei V; O'Reilly, Eoin P; Xu, Hongxing

    2014-05-01

    We study the emission of photoelectrons from plasmonic nanoparticles into a surrounding matrix. We consider two mechanisms of electron emission from the nanoparticles--surface and volume ones--and use models for these two mechanisms which allow us to obtain analytical results for the photoelectron emission rate from a nanoparticle. Calculations have been carried out for a step potential at the surface of a spherical nanoparticle, and a simple model for the hot electron cooling has been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary in the surface mechanism, which leads to a substantial (by ∼5 times) increase of the internal photoelectron emission rate from a nanoparticle compared to the case when such a discontinuity is absent. For a plasmonic nanoparticle, a comparison of the two photoeffect mechanisms was undertaken for the first time which showed that the surface photoeffect can in the general case be larger than the volume one, which agrees with the results obtained for a flat metal surface first formulated by Tamm and Schubin in their pioneering development of a quantum-mechanical theory of photoeffect in 1931. In accordance with our calculations, this possible predominance of the surface effect is based on two factors: (i) effective cooling of hot carriers during their propagation from the volume of the nanoparticle to its surface in the scenario of the volume mechanism and (ii) strengthening of the surface mechanism through the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary. The latter is stronger at relatively lower photon energies and correspondingly is more substantial for internal photoemission than for an external one. We show that in the general case, it is essential to take both mechanisms into account in the development of devices based on the photoelectric effect and when considering hot electron emission from a plasmonic nanoantenna.

  20. Microbial Characterization of Internal Active Thermal Control System (IATCS) Hardware Surfaces after Five Years of Operation in the International Space Station

    Science.gov (United States)

    Roman, Monsi C.; Weir, Natalee E.; Wilson, Mark E.; Pyle, Barry H.

    2006-01-01

    A flex hose assembly containing aqueous coolant from the International Space Station (ISS) Internal Active Thermal Control System (IATCS) consisting of a 2 foot section of Teflon hose and quick disconnects (QDs) and a Special Performance Checkout Unit (SPCU) heat exchanger containing separate channels of IATCS coolant and iodinated water used to cool spacesuits and Extravehicular Mobility Units (EMUS) were returned for destructive analyses on Shuttle return to flight mission STS-114. The original aqueous IATCS coolant used in Node 1, the Laboratory Module, and the Airlock consisted of water, borate (pH buffer), phosphate (corrosion control), and silver sulfate (microbiological control) at a pH of 9.5 +/- 0.5. Chemical changes occurred after on-orbit implementation including a decrease to pH 8.4 due to the diffusion of carbon dioxide through the Teflon hoses, an increase in nickel ions due to general corrosion of heat exchanger braze coatings, a decrease in phosphate concentration due to precipitation of nickel phosphate, and the rapid disappearance of silver ions due to deposition on hardware surfaces. Also associated with the coolant chemistry changes was an increase in planktonic microorganisms from less than 100 colony forming units (CFU) per 100 ml to approximately 1 million CFU per 100 ml. Attachment and growth of microorganisms to the system surfaces (biofilm) was suspected due to the levels of planktonic microorganisms in the coolant. Biofilms can reduce coolant flow, reduce heat transfer, amplify degradation of system materials initiated by chemical corrosion, and enhance mineral scale formation.

  1. Ground-based FTIR measurements of CO from the Jungfraujoch: characterisation and comparison with in situ surface andMOPITT data

    Directory of Open Access Journals (Sweden)

    E. Mahieu

    2003-09-01

    Full Text Available CO vertical profiles have been retrieved from solar absorption FTIR spectra recorded at the NDSC station of the Jungfraujoch (46.5° N, 8° E and 3580 m a.s.l. for the period from January 1997 to May 2001. The characterisation of these profiles has been established by an information content analysis and an estimation of the error budgets. A partial validation of the profiles has been performed through comparisons with correlative measurements. The average volume mixing ratios (vmr in the 3 km layer above the station have been compared with coincident surface measurements. The agreement between monthly means from both measurement techniques is very good, with a correlation coefficient of 0.87, and no significant bias observed. The FTIR total columns have also been compared to CO partial columns above 3580 m a.s.l. derived from the MOPITT (Measurement Of Pollution In The Troposphere instrument for the period March 2000 to May 2001. Relative to the FTIR columns, the MOPITT partial columns exhibit a positive bias of 8±8% for daytime and of 4±7% for nighttime measurements.

  2. Inter-Comparison of In-Situ Sensors for Land Surface Temperature Measurements

    Science.gov (United States)

    Krishnan, P.; Kochendorfer, J.; Meyers, T. P.; Guillevic, P. C.; Hook, S. J.

    2014-12-01

    Land Surface Temperature (LST) is a key variable in the determination of land surface processes from local to global scales. It has been identified as one of the most important environmental data records and is widely used in meteorological, climatological, hydrological, ecological, biophysical, and biochemical studies. Despite its importance, accurate in-situ measurements of LST are not yet available for the whole globe and are not routinely conducted at weather stations along with standard meteorological observations, with few exceptions including NOAA's United States Climate Reference Network. Even though satellite radiometric measurements of LST are a powerful tool, there are still large uncertainties associated with the retrieval of remotely sensed LST measurements. To improve confidence in the methods, algorithms, and parameters used to derive remotely sensed LST, validation of satellite data using high-quality ground-based measurements is required. With the objective of improving the quality of in situ measurements of LST and to evaluate the quantitative uncertainties in the ground-based measurements, intensive experiments were conducted at NOAA/ATDD in Oak ridge, TN from September 2013 to 2014. During the study period, multiple measurements of land surface skin temperature were made using infra-red temperature sensors - including the JPL radiometer, two models of Apogee infrared radiometers, and thermocouples embedded in the ground surface. In addition, aspirated air temperature and four-band net radiation measurements were also made. Overall the in situ LST measurements from the different sensors were in good agreement with each other, with a correlation coefficient of ~1 and root mean square error of <1 oC.

  3. Surface net solar radiation estimated from satellite measurements - Comparisons with tower observations

    Science.gov (United States)

    Li, Zhanqing; Leighton, H. G.; Cess, Robert D.

    1993-01-01

    A parameterization that relates the reflected solar flux at the top of the atmosphere to the net solar flux at the surface in terms of only the column water vapor amount and the solar zenith angle was tested against surface observations. Net surface fluxes deduced from coincidental collocated satellite-measured radiances and from measurements from towers in Boulder during summer and near Saskatoon in winter have mean differences of about 2 W/sq m, regardless of whether the sky is clear or cloudy. Furthermore, comparisons between the net fluxes deduced from the parameterization and from surface measurements showed equally good agreement when the data were partitioned into morning and afternoon observations. This is in contrast to results from an empirical clear-sky algorithm that is unable to account adequately for the effects of clouds and that shows, at Boulder, a distinct morning to afternoon variation. It is also demonstrated that the parameterization may be applied to irradiances at the top of the atmosphere that have been temporally averaged. The good agreement between the results of the parameterization and surface measurements suggests that the algorithm is a useful tool for a variety of climate studies.

  4. Surface Net Solar Radiation Estimated from Satellite Measurements: Comparisons with Tower Observations

    Science.gov (United States)

    Li, Zhanqing; Leighton, H. G.; Cess, Robert D.

    1993-01-01

    A parameterization that relates the reflected solar flux at the top of the atmosphere to the net solar flux at the surface in terms of only the column water vapor amount and the solar zenith angle was tested against surface observations. Net surface fluxes deduced from coincidental collocated satellite-measured radiances and from measurements from towers in Boulder during summer and near Saskatoon in winter have mean differences of about 2 W/sq m, regardless of whether the sky is clear or cloudy. Furthermore, comparisons between the net fluxes deduced from the parameterization and from surface measurements showed equally good agreement when the data were partitioned into morning and afternoon observations. This is in contrast to results from an empirical clear-sky algorithm that is unable to account adequately for the effects of clouds and that shows, at Boulder, a distinct morning to afternoon variation, which is presumably due to the predominance of different cloud types throughout the day. It is also demonstrated that the parameterization may be applied to irradiances at the top of the atmosphere that have been temporally averaged by using the temporally averaged column water vapor amount and the temporally averaged cosine of the solar zenith angle. The good agreement between the results of the parameterization and surface measurements suggests that the algorithm is a useful tool for a variety of climate studies.

  5. Point-surface fusion of station measurements and satellite observations for mapping PM2.5 distribution in China: Methods and assessment

    Science.gov (United States)

    Li, Tongwen; Shen, Huanfeng; Zeng, Chao; Yuan, Qiangqiang; Zhang, Liangpei

    2017-03-01

    Fine particulate matter (PM2.5, particulate matters with aerodynamic diameters less than 2.5 μm) is associated with adverse human health effects, and China is currently suffering from serious PM2.5 pollution. To obtain spatially continuous ground-level PM2.5 concentrations, several models established by the point-surface fusion of station measurements and satellite observations have been developed. However, how well do these models perform at national scale in China? Is there space to improve the estimation accuracy of PM2.5 concentration? The contribution of this study is threefold. Firstly, taking advantage of the newly established national monitoring network, we develop a national-scale generalized regression neural network (GRNN) model to estimate PM2.5 concentrations. Secondly, different assessment experiments are undertaken in time and space, to comprehensively evaluate and compare the performance of the widely used models. Finally, to map the yearly and seasonal mean distribution of PM2.5 concentrations in China, a pixel-based merging strategy is proposed. The results indicate that the conventional models (linear regression, multiple linear regression, and semi-empirical model) do not obtain the expected results at national scale, with cross-validation R values of 0.49-0.55 and RMSEs of 30.80-31.51 μg /m3 , respectively. In contrast, the more advanced models (geographically weighted regression, back-propagation neural network, and GRNN) have great advantages in PM2.5 estimation, with R values ranging from 0.61 to 0.82 and RMSEs from 20.93 to 28.68 μg /m3 , respectively. In particular, the proposed GRNN model obtains the best performance. Furthermore, the mapped PM2.5 distribution retrieved from 3-km MODIS aerosol optical depth (AOD) products agrees quite well with the station measurements. The results also show that the approach used in this study has the capacity to provide reasonable information for the global monitoring of PM2.5 pollution in China.

  6. Near surface geotechnical and geophysical data cross validated for site characterization applications. The cases of selected accelerometric stations in Crete island (Greece)

    Science.gov (United States)

    Loupasakis, Constantinos; Tsangaratos, Paraskevas; Rozos, Dimitrios; Rondoyianni, Theodora; Vafidis, Antonis; Steiakakis, Emanouil; Agioutantis, Zacharias; Savvaidis, Alexandros; Soupios, Pantelis; Papadopoulos, Ioannis; Papadopoulos, Nikos; Sarris, Apostolos; Mangriotis, Maria-Dafni; Dikmen, Unal

    2015-04-01

    The near surface ground conditions are highly important for the design of civil constructions. These conditions determine primarily the ability of the foundation formations to bear loads, the stress - strain relations and the corresponding deformations, as well as the soil amplification and corresponding peak ground motion in case of dynamic loading. The static and dynamic geotechnical parameters as well as the ground-type/soil-category can be determined by combining geotechnical and geophysical methods, such as engineering geological surface mapping, geotechnical drilling, in situ and laboratory testing and geophysical investigations. The above mentioned methods were combined for the site characterization in selected sites of the Hellenic Accelerometric Network (HAN) in the area of Crete Island. The combination of the geotechnical and geophysical methods in thirteen (13) sites provided sufficient information about their limitations, setting up the minimum tests requirements in relation to the type of the geological formations. The reduced accuracy of the surface mapping in urban sites, the uncertainties introduced by the geophysical survey in sites with complex geology and the 1-D data provided by the geotechnical drills are some of the causes affecting the right order and the quantity of the necessary investigation methods. Through this study the gradual improvement on the accuracy of the site characterization data in regards to the applied investigation techniques is presented by providing characteristic examples from the total number of thirteen sites. As an example of the gradual improvement of the knowledge about the ground conditions the case of AGN1 strong motion station, located at Agios Nikolaos city (Eastern Crete), is briefly presented. According to the medium scale geological map of IGME the station was supposed to be founded over limestone. The detailed geological mapping reveled that a few meters of loose alluvial deposits occupy the area, expected

  7. Comparison of Bayesian Land Surface Temperature algorithm performance with Terra MODIS observations

    CERN Document Server

    Morgan, J A

    2009-01-01

    An approach to land surface temperature (LST) estimation that relies upon Bayesian inference has been validated against multiband infrared radiometric imagery from the Terra MODIS instrument. Bayesian LST estimators are shown to reproduce standard MODIS product LST values starting from a parsimoniously chosen (hence, uninformative) range of prior band emissivity knowledge. Two estimation methods have been tested. The first is the iterative contraction mapping of joint expectation values for LST and surface emissivity described in a previous paper. In the second method, the Bayesian algorithm is reformulated as a Maximum \\emph{A-Posteriori} (MAP) search for the maximum joint \\emph{a-posteriori} probability for LST, given observed sensor aperture radiances and \\emph{a-priori} probabilities for LST and emissivity. Two MODIS data granules each for daytime and nighttime were used for the comparison. The granules were chosen to be largely cloud-free, with limited vertical relief in those portions of the granules fo...

  8. Comparison of climatic threshold of geographical distribution between dominant plants and surface pollen in China

    Institute of Scientific and Technical Information of China (English)

    CHEDDADI; Rachid; BEAUDOUIN; Celia

    2008-01-01

    The geographical distribution of dominant plant species in China was georeferenced and climatic variables were interpolated into all grids.Accordingly,the percentage distributions of principal pollen taxa based on 1860 surface pollen sites in China were selected and the related climate values were interpolated with the same method. The geographical and climatic comparison between the two data-sets indicated that the climate threshold of most pollen taxa from surface pollen is coherent with plant distributions. The climatic envelopes of dominant plant are mostly accordant with those of pollen taxa at certain levels. However, some distinct offsets of the climate ranges exist between the two datasets for most pollen taxa identified at family level, such as Ericaceae,Asteraceae, Poaceae and Chenopodiaceae. The present study provides for the first time rich information on temperature and precipitation in relation to pollen and plant distribution based on the datasets on a continental scale useful for global ecological modeling and Quaternary palaeoclimate reconstruction.

  9. The Way We Measure: Comparison of Methods to Derive Radial Surface Brightness Profiles

    CERN Document Server

    Peters, S P C; de Jong, R S

    2016-01-01

    The breaks and truncations in the luminosity profile of face-on spiral galaxies offer valuable insights in their formation history. The traditional method of deriving the surface photometry profile for face-on galaxies is to use elliptical averaging. In this paper, we explore the question whether elliptical averaging is the best way to do this. We apply two additional surface photometry methods, one new: principle axis summation, and one old that has become seldom used: equivalent profiles. These are compared to elliptically averaged profiles using a set of 29 face-on galaxies. We find that the equivalent profiles match extremely well with elliptically averaged profiles, confirming the validity of using elliptical averaging. The principle axis summation offers a better comparison to edge-on galaxies.

  10. UMTS Network Stations

    Science.gov (United States)

    Hernandez, C.

    2010-09-01

    The weakness of small island electrical grids implies a handicap for the electrical generation with renewable energy sources. With the intention of maximizing the installation of photovoltaic generators in the Canary Islands, arises the need to develop a solar forecasting system that allows knowing in advance the amount of PV generated electricity that will be going into the grid, from the installed PV power plants installed in the island. The forecasting tools need to get feedback from real weather data in "real time" from remote weather stations. Nevertheless, the transference of this data to the calculation computer servers is very complicated with the old point to point telecommunication systems that, neither allow the transfer of data from several remote weather stations simultaneously nor high frequency of sampling of weather parameters due to slowness of the connection. This one project has developed a telecommunications infrastructure that allows sensorizadas remote stations, to send data of its sensors, once every minute and simultaneously, to the calculation server running the solar forecasting numerical models. For it, the Canary Islands Institute of Technology has added a sophisticated communications network to its 30 weather stations measuring irradiation at strategic sites, areas with high penetration of photovoltaic generation or that have potential to host in the future photovoltaic power plants connected to the grid. In each one of the stations, irradiance and temperature measurement instruments have been installed, over inclined silicon cell, global radiation on horizontal surface and room temperature. Mobile telephone devices have been installed and programmed in each one of the weather stations, which allow the transfer of their data taking advantage of the UMTS service offered by the local telephone operator. Every minute the computer server running the numerical weather forecasting models receives data inputs from 120 instruments distributed

  11. The Effect of Warming Oceans at a Tide Gauge Station

    Science.gov (United States)

    Bâki Iz, H.

    2016-09-01

    This study proposes a new paradigm for assessing thermosteric effects of warming oceans at a tide gauge station. For demonstration, the trend due to the global thermosteric sea level at the Key West, FL tide gauge station was estimated using the tide gauge measurements and the global sea surface temperature anomalies that were represented by yearly distributed lags. A comparison of the estimate with the trend estimate from a descriptive model revealed that 0.7±0.1 mm/yr, (pglobal warming of the oceans during the last century at this station. The remaining 1.5±0.1 mm/yr, 70 percent of the total trend, is the lump sum estimate of the secular changes due to the eustatic, halosteric, and various local isostatic contributions.

  12. A comparison of semiglobal and local dense matching algorithms for surface reconstruction

    Science.gov (United States)

    Dall'Asta, E.; Roncella, R.

    2014-06-01

    Encouraged by the growing interest in automatic 3D image-based reconstruction, the development and improvement of robust stereo matching techniques is one of the most investigated research topic of the last years in photogrammetry and computer vision. The paper is focused on the comparison of some stereo matching algorithms (local and global) which are very popular both in photogrammetry and computer vision. In particular, the Semi-Global Matching (SGM), which realizes a pixel-wise matching and relies on the application of consistency constraints during the matching cost aggregation, will be discussed. The results of some tests performed on real and simulated stereo image datasets, evaluating in particular the accuracy of the obtained digital surface models, will be presented. Several algorithms and different implementation are considered in the comparison, using freeware software codes like MICMAC and OpenCV, commercial software (e.g. Agisoft PhotoScan) and proprietary codes implementing Least Square e Semi-Global Matching algorithms. The comparisons will also consider the completeness and the level of detail within fine structures, and the reliability and repeatability of the obtainable data.

  13. Computer Aided Design of Transformer Station Grounding System Using CDEGS Software

    Directory of Open Access Journals (Sweden)

    S. Nikolovski

    2004-01-01

    Full Text Available This paper presents a computer-aided design of a transformer station grounding system. Fault conditions in a transformer station can produce huge damage to transformer station equipment if the grounding system is not designed properly. A well designed grounding system is a very important part of the project for transformer station design as a whole. This paper analyses a procedure for transformer grounding system design and spatial distribution of touch and step voltage on the ground surface level, using the CDEGS (Current Distribution Electromagnetic Interference Grounding and Soil Structure Analysis software. Spatial distribution is needed for checking and finding dangerous step and touch voltages above and around the transformer station. Apparent earth resistivity data is measured and analyzed using the RESAP module of the CDEGS software. Because of the very high current flow into the grounding system during a single line to ground fault or a three phase fault in the transformer station, very high and dangerous potentials can be induced on the metallic structures including the fence, which can cause dangerous situations for people and animals near the station and for the personnel inside the station. The PLOT module of CDEGS is used to view the results of the scalar potential, step and touch voltage on the surface. Graphic displays include equipotent contour lines and potential profiles (gradients in 3D and 2D perspective and apparent soil resistivity (Wm versus inter electrode spacing (m. The results of alternative grid designs may be displayed simultaneously for the purpose of comparison.

  14. A comparison of surface NO2 mixing ratios and total column observations at a South African site

    OpenAIRE

    Josipovic, Micky; Burger, Roelof P.; Thompson, Anne M.; Beukes, Johan P.; Zyl, Pieter G.; Venter, Andrew D.; Jaars, Kerneels; Laakso, Lauri

    2014-01-01

    The total column density nitrogen dioxide (NO2) retrievals collated by a ground-based sun-tracking spectrometer (Pandora/GSFC) and the satellite-borne (Aura) Ozone Monitoring Instrument (OMI) were compared to the volume mixing ratios measured by a ground-based gas-analyser at Welgegund, North-West University (NWU) atmospheric monitoring station (Potchefstroom, South Africa). An assessment of the comparability between columnar and surface NO2 measurements was performed. The c...

  15. CHARACTERIZATION OF FRENCH ACCELEROMETRIC PERMANENT NETWORK STATIONS WITH SURFACE-WAVE BASED METHODS: IMPORTANCE OF JOINT USE OF ACTIVE AND PASSIVE METHODS, LOVE AND RAYLEIGH WAVES

    OpenAIRE

    Hollender, F.; Cornou, C; Dechamp, A; Renalier, F.; Thomassin, S; Bard, P.-Y.

    2017-01-01

    International audience; Data provided by accelerometric networks are important for seismic hazard assessment. They are key to derive Ground Motion Prediction Equations (GMPEs). The correct use of accelerometric signal is also linked to the station site metadata that include reliable information about site class (VS30), velocity profiles, and other relevant information that can help to quantify the site effect associated to stations. In France, the permanent accelerometric network consists of ...

  16. Comparison of different Geostatistical Approaches to map Sea Surface Temperature (SST) of Southern South China Sea

    Science.gov (United States)

    Ali, Azizi; Mohd Muslim, Aidy; Lokman Husain, Mohd; Fadzil Akhir, Mohd

    2013-04-01

    Sea surface temperature (SST) variation provides vital information for weather and ocean forecasting especially when studying climate change. Conventional methods of collecting ocean parameters such as SST, remains expensive and labor intensive due to the large area coverage and complex analytical procedure required. Therefore, some studies need to be conducted on the spatial and temporal distribution of ocean parameters. This study looks at Geo-statisctical methods in interpolating SST values and its impact on accuracy. Two spatial Geo-statistical techniques, mainly kriging and inverse distance functions (IDW) were applied to create variability distribution maps of SST for the Southern South China Sea (SCS). Data from 72 sampling station was collected in July 2012 covering an area of 270 km x 100 km and 263 km away from shore. This data provide the basis for the interpolation and accuracy analysis. After normalization, variograms were computed to fit the data sets producing models with the least RSS value. The accuracy were later evaluated based on on root mean squared error (RMSE) and root mean kriging variance (RMKV). Results show that Kriging with exponential model produced most accuracy estimates, reducing error in 17.3% compared with inverse distance functions.

  17. Comparison of Flow Characteristics of Different Sphere Geometries Under the Free Surface Effect

    Directory of Open Access Journals (Sweden)

    Sahin B.

    2013-04-01

    Full Text Available Comparison of the experimental results of turbulent flow structures between a smooth sphere and a sphere with a vent hole, roughened, and o-ring is presented in the presence of a free-surface. Dye visualization and particle image velocimetry (PIV techniques were performed to examine effects of passive control methods on the sphere wake for Reynolds number Re = 5000 based on the sphere diameter with a 42.5mm in an open water channel. Instantaneous and time-averaged flow patterns in the wake region of the sphere were examined from point of flow physics for the different sphere locations in the range of 0≤h/D≤2.0 where h was the space between the top point of the sphere and the free surface. The ratio of ventilation hole to sphere diameter was 0.15, o-ring was located at 55° with a 2 mm from front stagnation point of the sphere and roughened surface was formed by means of totally 410 circular holes with a 3 mm diameter and around 2 mm depth in an equilateral triangle arrangement. The flow characteristics of instantaneous velocity vectors, vorticity contours, time-averaged streamline patterns, Reynolds stress correlations and streamwise and cross-stream velocity fluctuations for both the smooth and passively controlled sphere were interpreted.

  18. Comparison of Flow Characteristics of Different Sphere Geometries Under the Free Surface Effect

    Science.gov (United States)

    Ozgoren, M.; Dogan, S.; Okbaz, A.; Aksoy, M. H.; Sahin, B.; Akıllı, H.

    2013-04-01

    Comparison of the experimental results of turbulent flow structures between a smooth sphere and a sphere with a vent hole, roughened, and o-ring is presented in the presence of a free-surface. Dye visualization and particle image velocimetry (PIV) techniques were performed to examine effects of passive control methods on the sphere wake for Reynolds number Re = 5000 based on the sphere diameter with a 42.5mm in an open water channel. Instantaneous and time-averaged flow patterns in the wake region of the sphere were examined from point of flow physics for the different sphere locations in the range of 0≤h/D≤2.0 where h was the space between the top point of the sphere and the free surface. The ratio of ventilation hole to sphere diameter was 0.15, o-ring was located at 55° with a 2 mm from front stagnation point of the sphere and roughened surface was formed by means of totally 410 circular holes with a 3 mm diameter and around 2 mm depth in an equilateral triangle arrangement. The flow characteristics of instantaneous velocity vectors, vorticity contours, time-averaged streamline patterns, Reynolds stress correlations and streamwise and cross-stream velocity fluctuations for both the smooth and passively controlled sphere were interpreted.

  19. Comparison of CFD Predictions with Shuttle Global Flight Thermal Imagery and Discrete Surface Measurements

    Science.gov (United States)

    Wood, William A.; Kleb, William L.; Tang, chun Y.; Palmer, Grant E.; Hyatt, Andrew J.; Wise, Adam J.; McCloud, Peter L.

    2010-01-01

    Surface temperature measurements from the STS-119 boundary-layer transition experiment on the space shuttle orbiter Discovery provide a rare opportunity to assess turbulent CFD models at hypersonic flight conditions. This flight data was acquired by on-board thermocouples and by infrared images taken off-board by the Hypersonic Thermodynamic Infrared Measurements (HYTHIRM) team, and is suitable for hypersonic CFD turbulence assessment between Mach 6 and 14. The primary assessment is for the Baldwin-Lomax and Cebeci-Smith algebraic turbulence models in the DPLR and LAURA CFD codes, respectively. A secondary assessment is made of the Shear-Stress Transport (SST) two-equation turbulence model in the DPLR code. Based upon surface temperature comparisons at eleven thermocouple locations, the algebraic-model turbulent CFD results average 4% lower than the measurements for Mach numbers less than 11. For Mach numbers greater than 11, the algebraic-model turbulent CFD results average 5% higher than the three available thermocouple measurements. Surface temperature predictions from the two SST cases were consistently 3 4% higher than the algebraic-model results. The thermocouple temperatures exhibit a change in trend with Mach number at about Mach 11; this trend is not reflected in the CFD results. Because the temperature trends from the turbulent CFD simulations and the flight data diverge above Mach 11, extrapolation of the turbulent CFD accuracy to higher Mach numbers is not recommended.

  20. Investigation of surface ozone variability in the central Mediterranean basin by observations at the Lampedusa and Capo Granitola WMO/GAW Regional Stations.

    Science.gov (United States)

    Cristofanelli, Paolo; Bonasoni, Paolo; Anello, Fabrizio; Becagli, Silvia; Di Sarra, Alcide Giorgio; Marinoni, Angela; Piacentino, Salvatore; Putero, Davide; Sferlazzo, Damiano; Calzolari, Francescopiero; Busetto, Maurizio

    2017-04-01

    The Mediterranean Basin is considered a hot-spot region in term of air-quality and climate change due to the impact of anthropogenic and natural processes. Meteorological conditions such as frequent clear sky and high solar radiation in summer enhance the formation of photochemical ozone (O3) due to the availability of natural and anthropogenic precursors. In particular, large amounts of anthropogenic pollutants emitted in continental Europe and northern Africa are transported towards the basin where intense photochemical O3 production occurs. Modeling scenarios and satellite investigations show the central Mediterranean basin (i.e. from 5°E to 20°E) as the region where O3 is maximized in summer at the surface. Moreover, stratospheric-tropospheric exchange, STE, was recognized to affect tropospheric O3 variability in the Eastern basin but with signal still detectable in the central Mediterranean basin. Continuous surface O3 observations have been carried out since 2015 at two locations in the central Mediterranean basin: Lampedusa Island (35.52°N, 12.63°E, 45 m a.s.l.) and Capo Granitola (southern Sicily, 37.57°N, 12.59°E, 5 m a.s.l ). Capo Granitola is well representative of the atmospheric background conditions, with a limited impact of local/regional emissions under land breeze circulation. Lampedusa is a small island South of the Strait of Sicily with very limited local anthropogenic emissions. The comparison of surface O3 and other atmospheric variables at these two measurement sites, together with the integration of Lagrangian and Eulerian modeling tools, provides the unique opportunity to investigate several processes able to affect surface O3 in the Mediterranean basin, namely Saharan dust transport, stratosphere-to-troposphere exchange, ship and biomass burning emissions and air-mass outflow from southern Italy. To identify the occurrence of these kind of events and provide a preliminary assessment on the O3 variability, we analysed 3D air-mass back

  1. Hydrometry's classical and Innovative methods and tools comparison for Stara river flows at Agios Germanos monitoring station in north-west Greece.

    Science.gov (United States)

    Filintas, Agathos, , Dr; Hatzigiannakis, Evagellos, , Dr; Arampatzis, George, , Dr; Ilias, Andreas; Panagopoulos, Andreas, , Dr; Hatzispiroglou, Ioannis

    2015-04-01

    The aim of the present study is a thorough comparison of hydrometry's conventional and innovative methods-tools for river flow monitoring. A case study was conducted in Stara river at Agios Germanos monitoring station (northwest Greece), in order to investigate possible deviations between conventional and innovative methods-tools on river flow velocity and discharge. For this study, two flowmeters were used, which manufac-tured in 2013 (OTT Messtechnik Gmbh, 2013), as follows: a) A conventional propeller flow velocity meter (OTT-Model C2) which is a me-chanical current flow meter with a certification of calibration BARGO, operated with a rod and a relocating device, along with a digital measuring device including an elec-tronic flow calculator, data logger and real time control display unit. The flowmeter has a measurement velocity range 0.025-4.000 m/s. b) An innovative electromagnetic flowmeter (OTT-Model MF pro) which it is con-sisted of a compact and light-weight sensor and a robust handheld unit. Both system components are designed to be attached to conventional wading rods. The electromag-netic flowmeter uses Faraday's Law of electromagnetic induction to measure the process flow. When an electrically conductive fluid flows along the meter, an electrode voltage is induced between a pair of electrodes placed at right angles to the direction of mag-netic field. The electrode voltage is directly proportional to the average fluid velocity. The electromagnetic flowmeter was operated with a rod and relocating device, along with a digital measuring device with various logging and graphical capabilities and vari-ous methods of velocity measurement (ISO/USGS standards). The flowmeter has a measurement velocity range 0.000-6.000 m/s. The river flow data were averaged over a pair measurement of 60+60 seconds and the measured river water flow velocity, depths and widths of the segments were used for the estimation of cross-section's mean flow velocity in each measured

  2. Sea surface temperature of the mid-Piacenzian ocean: a data-model comparison.

    Science.gov (United States)

    Dowsett, Harry J; Foley, Kevin M; Stoll, Danielle K; Chandler, Mark A; Sohl, Linda E; Bentsen, Mats; Otto-Bliesner, Bette L; Bragg, Fran J; Chan, Wing-Le; Contoux, Camille; Dolan, Aisling M; Haywood, Alan M; Jonas, Jeff A; Jost, Anne; Kamae, Youichi; Lohmann, Gerrit; Lunt, Daniel J; Nisancioglu, Kerim H; Abe-Ouchi, Ayako; Ramstein, Gilles; Riesselman, Christina R; Robinson, Marci M; Rosenbloom, Nan A; Salzmann, Ulrich; Stepanek, Christian; Strother, Stephanie L; Ueda, Hiroaki; Yan, Qing; Zhang, Zhongshi

    2013-01-01

    The mid-Piacenzian climate represents the most geologically recent interval of long-term average warmth relative to the last million years, and shares similarities with the climate projected for the end of the 21(st) century. As such, it represents a natural experiment from which we can gain insight into potential climate change impacts, enabling more informed policy decisions for mitigation and adaptation. Here, we present the first systematic comparison of Pliocene sea surface temperature (SST) between an ensemble of eight climate model simulations produced as part of PlioMIP (Pliocene Model Intercomparison Project) with the PRISM (Pliocene Research, Interpretation and Synoptic Mapping) Project mean annual SST field. Our results highlight key regional and dynamic situations where there is discord between the palaeoenvironmental reconstruction and the climate model simulations. These differences have led to improved strategies for both experimental design and temporal refinement of the palaeoenvironmental reconstruction.

  3. Comparison of Digital Surface Models for Snow Depth Mapping with Uav and Aerial Cameras

    Science.gov (United States)

    Boesch, R.; Bühler, Y.; Marty, M.; Ginzler, C.

    2016-06-01

    Photogrammetric workflows for aerial images have improved over the last years in a typically black-box fashion. Most parameters for building dense point cloud are either excessive or not explained and often the progress between software releases is poorly documented. On the other hand, development of better camera sensors and positional accuracy of image acquisition is significant by comparing product specifications. This study shows, that hardware evolutions over the last years have a much stronger impact on height measurements than photogrammetric software releases. Snow height measurements with airborne sensors like the ADS100 and UAV-based DSLR cameras can achieve accuracies close to GSD * 2 in comparison with ground-based GNSS reference measurements. Using a custom notch filter on the UAV camera sensor during image acquisition does not yield better height accuracies. UAV based digital surface models are very robust. Different workflow parameter variations for ADS100 and UAV camera workflows seem to have only random effects.

  4. Development of ballistics identification—from image comparison to topography measurement in surface metrology

    Science.gov (United States)

    Song, J.; Chu, W.; Vorburger, T. V.; Thompson, R.; Renegar, T. B.; Zheng, A.; Yen, J.; Silver, R.; Ols, M.

    2012-05-01

    Fired bullets and ejected cartridge cases have unique ballistics signatures left by the firearm. By analyzing the ballistics signatures, forensic examiners can trace these bullets and cartridge cases to the firearm used in a crime scene. Current automated ballistics identification systems are primarily based on image comparisons using optical microscopy. The correlation accuracy depends on image quality which is largely affected by lighting conditions. Because ballistics signatures are geometrical micro-topographies by nature, direct measurement and correlation of the surface topography is being investigated for ballistics identification. A Two-dimensional and Three-dimensional Topography Measurement and Correlation System was developed at the National Institute of Standards and Technology for certification of Standard Reference Material 2460/2461 bullets and cartridge cases. Based on this system, a prototype system for bullet signature measurement and correlation has been developed for bullet signature identifications, and has demonstrated superior correlation results.

  5. Comparison of MESSENGER Optical Images with Thermal and Radar Data for the Surface of MERCURY

    Science.gov (United States)

    Blewett, D. T.; Coman, E. I.; Chabot, N. L.; Izenberg, N. R.; Harmon, J. K.; Neish, C.

    2010-12-01

    Images collected by the MESSENGER spacecraft during its three Mercury flybys cover nearly the entire surface of the planet that was not imaged by Mariner 10. The MESSENGER data now allow us to observe features at optical wavelengths that were previously known only through remote sensing in other portions of the electromagnetic spectrum. For example, the Mariner 10 infrared (IR) radiometer made measurements along a track on the night side of Mercury during the spacecraft's first encounter in 1974. Analysis of the IR radiometer data identified several thermal anomalies that we have correlated to craters with extensive rays or ejecta deposits, including Xiao Zhao and Eminescu. The thermal properties are consistent with a greater exposure of bare rock (exposed in steep walls or as boulders and cobbles) in and around these craters compared with the lower-thermal-inertia, finer-grained regolith of the surrounding older surface. The portion of Mercury not viewed by Mariner 10 has also been imaged by Earth-based radar. The radar backscatter gives information on the wavelength-scale surface roughness. Arecibo S-band (12.6-cm wavelength) radar observations have produced images of Eminescu and also revealed two spectacular rayed craters (Debussy and Hokusai) that have since been imaged by MESSENGER. We are examining radial profiles for these craters, extracted from both the radar images and MESSENGER narrow-angle camera mosaics, that extend from the crater center outwards to a distance of several crater diameters. Comparison of optical and radar profiles for the craters, as well as similar profiles for lunar craters, can provide insight into ejecta deposition, the effect of surface gravity on the cratering process, and space weathering.

  6. Modelling the spring ozone maximum and the interhemispheric asymmetry in the remote marine boundary layer 1. Comparison with surface and ozonesonde measurements

    CERN Document Server

    Wang, Kuo-Ying; Pyle, John A

    2008-01-01

    Here we report a modelling study of the spring ozone maximum and its interhemispheric asymmetry in the remote marine boundary layer (MBL). The modelled results are examined at the surface and on a series of time-height cross sections at several locations spread over the Atlantic, the Indian, and the Pacific Oceans. Comparison of model with surface measurements at remote MBL stations indicate a close agreement. The most striking feature of the hemispheric spring ozone maximum in the MBL can be most easily identified at the NH sites of Westman Island, Bermuda, and Mauna Loa, and at the SH site of Samoa. Modelled ozone vertical distributions in the troposphere are compared with ozone profiles. For the Atlantic and the Indian sites, the model generally produces a hemispheric spring ozone maximum close to those of the measurements. The model also produces a spring ozone maximum in the northeastern and tropical north Pacific close to those measurements, and at sites in the NH high latitudes. The good agreement betw...

  7. Comparison of AVHRR and ECMWF ERA-Interim data with buoy observational data for sea surface temperature over the Southern Coast of the Caspian Sea

    Science.gov (United States)

    Ghafarian, Parvin; Pegahfar, Nafiseh

    2016-07-01

    Sea surface temperature plays an important role in formation or intensification of many atmospheric phenomena such as tropical storms, lake-effect snow and sea breeze. Also, this variable is one of the input data in atmospheric, climate and oceanic models and also used climate change interpretation. According to the sparse location of observational stations over the ocean basins and seas, so satellite products can play an important role over such areas. The southern coast of the Caspian Sea (CS) is a prone area to experience some extreme challenging events forming due to sea surface temperature (SST) variation. In this research, SST data obtained by the AVHRR (Advanced Very High Resolution Radiometer) and those modeled by ECMWF data have been compared with observational data from buoy instrument. The horizontal resolution of AVHRR data is 0.125 degree, while that is 0.75 degree for ECMWF. The comparison process has been done in various seasons especially for some stormy days in winter and spring led to the lake-effect snow and waterspout. Analysis has been done applying nearest-neighbor interpolation and statistical methods. Our findings indicated that SST measured by AVHRR, comparing with ECMWF data, is more close to the observational data.

  8. Comparison between GIPSY OASIS 6.0 and BERNESE 5.0 time series for long term GPS stations in Denmark

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Knudsen, Per

    2012-01-01

    We study influence of software on determination of secular uplift rates. For this purpose we process GPS data for three long term permanent GPS stations, SMID, SULD, and BUDP, all located in Denmark (fig 1). To process the GPS data, we use the GIPSY OASIS 6.0 software and the Bernese 5.0 software...

  9. The occurrence of selected hydrocarbons in food on sale at petrol station shops and comparison with food from other shops: a literature survey

    NARCIS (Netherlands)

    Wolf, J.M. de; Beld, C.M.B. van den; Gennart, J.-Ph.; Riley, A.J.; Urbanus, J.

    2000-01-01

    A review of reports on the occurrence of some hydrocarbons in food in relation to the sales location, with emphasis on petrol station shops, covers the principal selected hydrocarbons, i.e., volatile components of gasoline, e.g., benzene, pentane, hexane, toluene, MTBE, and xylene; relevance of gaso

  10. The occurrence of selected hydrocarbons in food on sale at petrol station shops and comparison with food from other shops: a literature survey

    NARCIS (Netherlands)

    Wolf, J.M. de; Beld, C.M.B. van den; Gennart, J.-Ph.; Riley, A.J.; Urbanus, J.

    2000-01-01

    A review of reports on the occurrence of some hydrocarbons in food in relation to the sales location, with emphasis on petrol station shops, covers the principal selected hydrocarbons, i.e., volatile components of gasoline, e.g., benzene, pentane, hexane, toluene, MTBE, and xylene; relevance of

  11. Modeling of mean radiant temperature based on comparison of airborne remote sensing data with surface measured data

    Science.gov (United States)

    Chen, Yu-Cheng; Chen, Chih-Yu; Matzarakis, Andreas; Liu, Jin-King; Lin, Tzu-Ping

    2016-06-01

    Assessment of outdoor thermal comfort is becoming increasingly important due to the urban heat island effect, which strongly affects the urban thermal environment. The mean radiant temperature (Tmrt) quantifies the effect of the radiation environment on humans, but it can only be estimated based on influencing parameters and factors. Knowledge of Tmrt is important for quantifying the heat load on human beings, especially during heat waves. This study estimates Tmrt using several methods, which are based on climatic data from a traditional weather station, microscale ground surface measurements, land surface temperature (LST) and light detection and ranging (LIDAR) data measured using airborne devices. Analytical results reveal that the best means of estimating Tmrt combines information about LST and surface elevation information with meteorological data from the closest weather station. The application in this method can eliminate the inconvenience of executing a wide range ground surface measurement, the insufficient resolution of satellite data and the incomplete data of current urban built environments. This method can be used to map a whole city to identify hot spots, and can be contributed to understanding human biometeorological conditions quickly and accurately.

  12. Mid-Piacensian mean annual sea surface temperature: an analysis for data-model comparisons

    Science.gov (United States)

    Dowsett, Harry J.; Robinson, Marci M.; Foley, Kevin M.; Stoll, Danielle K.

    2010-01-01

    Numerical models of the global climate system are the primary tools used to understand and project climate disruptions in the form of future global warming. The Pliocene has been identified as the closest, albeit imperfect, analog to climate conditions expected for the end of this century, making an independent data set of Pliocene conditions necessary for ground truthing model results. Because most climate model output is produced in the form ofmean annual conditions, we present a derivative of the USGS PRISM3 Global Climate Reconstruction which integrates multiple proxies of sea surface temperature (SST) into single surface temperature anomalies. We analyze temperature estimates from faunal and floral assemblage data,Mg/Ca values and alkenone unsaturation indices to arrive at a single mean annual SST anomaly (Pliocene minus modern) best describing each PRISM site, understanding that multiple proxies should not necessarily show concordance. The power of themultiple proxy approach lies within its diversity, as no two proxies measure the same environmental variable. This data set can be used to verify climate model output, to serve as a starting point for model inter-comparisons, and for quantifying uncertainty in Pliocene model prediction in perturbed physics ensembles.

  13. Characterization of load bearing metrological parameters in reptilian exuviae in comparison to precision finished cylinder liner surfaces

    CERN Document Server

    Abdel-Aal, H A

    2014-01-01

    Design of precise functional surfaces is essential for many future applications. In the technological realm, the accumulated experience with the construction of such surfaces is not sufficient. Nature provides many examples of dynamic surfaces worthy of study and adoption, at least as a concept, within human engineering. In this work, we probe load-bearing features of the ventral skin of snake surfaces. We examine the structure of two snake species that mainly move by rectilinear locomotion. These are Python regius (pythonidae) and Bittis gabonica (Vipridae). To this end, we focus on the load bearing characteristics of the ventral skin surface (i.e. the Rk family of parameters). Therefore, we draw detailed comparison between the reptilian surfaces and two sets of technological data. The first set pertains to an actual commercial cylinder liner, whereas, the second set is a summary of recommended surface finish metrological values for several commercial cylinder liner manufacturers. The results highlight sever...

  14. Determining the IV fluids required for a ten day medical emergency on Space Station Freedom - Comparison of packaged vs. on-orbit produced solutions

    Science.gov (United States)

    Creager, Gerald J.; Lloyd, Charles W.

    1991-01-01

    To aid planning for the storage of supplies onboard Space Station Freedom, an estimate was made of the amount of intravenous (IV) fluid required to support a patient who has suffered a medical emergency for a period of up to 10 days. Six different medical scenarios were evaluated, and the volume of IV fluids required for each scenario was estimated. Up to 220 liters of fluid would be required to support a patient for all of the scenarios. When optimizing the volumes to support any single scenario, a total of 123 liters is required. Use of a water polishing system to produce sterile water for injection from potable supplies and on-station formulation of IV fluids results in a smaller mass and volume requirement for the Fluid Therapy Subsystem than carrying prepackaged bags of fluid.

  15. Controlled Directional Solidification of Aluminum - 7 wt Percent Silicon Alloys: Comparison Between Samples Processed on Earth and in the Microgravity Environment Aboard the International Space Station

    Science.gov (United States)

    Grugel, Richard N.; Tewari, Surendra N.; Erdman, Robert G.; Poirier, David R.

    2012-01-01

    An overview of the international "MIcrostructure Formation in CASTing of Technical Alloys" (MICAST) program is given. Directional solidification processing of metals and alloys is described, and why experiments conducted in the microgravity environment aboard the International Space Station (ISS) are expected to promote our understanding of this commercially relevant practice. Microstructural differences observed when comparing the aluminum - 7 wt% silicon alloys directionally solidified on Earth to those aboard the ISS are presented and discussed.

  16. Characterization of culturable Paenibacillus spp. from the snow surface on the high Antarctic Plateau (DOME C) and their dissemination in the Concordia research station.

    Science.gov (United States)

    Van Houdt, Rob; Deghorain, Marie; Vermeersch, Marjorie; Provoost, Ann; Lo Giudice, Angelina; Leys, Natalie; Perez-Morga, David; Van Melderen, Laurence; Michaud, Luigi

    2013-07-01

    Culturable psychrotolerant bacteria were isolated from the top snow on the high Antarctic Plateau surrounding the research station Concordia. A total of 80 isolates were recovered, by enrichment cultures, from two different isolation sites (a distant pristine site [75° S 123° E] and a site near the secondary runway of Concordia). All isolates were classified to the genus Paenibacillus by 16S rRNA gene phylogenetic analysis and belonged to two different species (based on threshold of 97 % similarity in 16S rRNA gene sequence). ERIC-PCR fingerprinting indicated that the isolates from the two different sites were not all clonal. All isolates grew well from 4 to 37 °C and were resistant to ampicillin and streptomycin. In addition, the isolates from the secondary runway were resistant to chromate and sensitive to chloramphenicol, contrary to those from the pristine site. The isolates were compared to 29 Paenibacillus isolates, which were previously recovered from inside the Concordia research station. One of these inside isolates showed ERIC- and REP-PCR fingerprinting profiles identical to those of the runway isolates and was the only inside isolate that was resistant to chromate and sensitive to chloramphenicol. The latter suggested that dissemination of culturable Paenibacillus strains between the harsh Antarctic environment and the inside of the Concordia research station occurred. In addition, inducible prophages, which are potentially involved in horizontal dissemination of genes, were detected in Paenibacillus isolates recovered from outside and inside the station. The highest lysogeny was observed in strains harvested from the hostile environment outside the station.

  17. Orbit determination error analysis and comparison of station-keeping costs for Lissajous and halo-type libration point orbits and sensitivity analysis using experimental design techniques

    Science.gov (United States)

    Gordon, Steven C.

    1993-01-01

    Spacecraft in orbit near libration point L1 in the Sun-Earth system are excellent platforms for research concerning solar effects on the terrestrial environment. One spacecraft mission launched in 1978 used an L1 orbit for nearly 4 years, and future L1 orbital missions are also being planned. Orbit determination and station-keeping are, however, required for these orbits. In particular, orbit determination error analysis may be used to compute the state uncertainty after a predetermined tracking period; the predicted state uncertainty levels then will impact the control costs computed in station-keeping simulations. Error sources, such as solar radiation pressure and planetary mass uncertainties, are also incorporated. For future missions, there may be some flexibility in the type and size of the spacecraft's nominal trajectory, but different orbits may produce varying error analysis and station-keeping results. The nominal path, for instance, can be (nearly) periodic or distinctly quasi-periodic. A periodic 'halo' orbit may be constructed to be significantly larger than a quasi-periodic 'Lissajous' path; both may meet mission requirements, but perhaps the required control costs for these orbits are probably different. Also for this spacecraft tracking and control simulation problem, experimental design methods can be used to determine the most significant uncertainties. That is, these methods can determine the error sources in the tracking and control problem that most impact the control cost (output); it also produces an equation that gives the approximate functional relationship between the error inputs and the output.

  18. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    future. Project partners also conducted a workshop on hydrogen safety and permitting. This provided an opportunity for the various permitting agencies and end users to gather to share experiences and knowledge. As a result of this workshop, the permitting process for the hydrogen filling station on the Las Vegas Valley Water District’s land was done more efficiently and those who would be responsible for the operation were better educated on the safety and reliability of hydrogen production and storage. The lessons learned in permitting the filling station and conducting this workshop provided a basis for future hydrogen projects in the region. Continuing efforts to increase the working pressure of electrolysis and efficiency have been pursued. Research was also performed on improving the cost, efficiency and durability of Proton Exchange Membrane (PEM) hydrogen technology. Research elements focused upon PEM membranes, electrodes/catalysts, membrane-electrode assemblies, seals, bipolar plates, utilization of renewable power, reliability issues, scale, and advanced conversion topics. Additionally, direct solar-to-hydrogen conversion research to demonstrate stable and efficient photoelectrochemistry (PEC) hydrogen production systems based on a number of optional concepts was performed. Candidate PEC concepts included technical obstacles such as inefficient photocatalysis, inadequate photocurrent due to non-optimal material band gap energies, rapid electron-hole recombination, reduced hole mobility and diminished operational lifetimes of surface materials exposed to electrolytes. Project Objective 1: Design, build, operate hydrogen filling station Project Objective 2: Perform research and development for utilizing solar technologies on the hydrogen filling station and convert two utility vehicles for use by the station operators Project Objective 3: Increase capacity of hydrogen filling station; add additional vehicle; conduct safety workshop; develop a roadmap for

  19. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    future. Project partners also conducted a workshop on hydrogen safety and permitting. This provided an opportunity for the various permitting agencies and end users to gather to share experiences and knowledge. As a result of this workshop, the permitting process for the hydrogen filling station on the Las Vegas Valley Water District’s land was done more efficiently and those who would be responsible for the operation were better educated on the safety and reliability of hydrogen production and storage. The lessons learned in permitting the filling station and conducting this workshop provided a basis for future hydrogen projects in the region. Continuing efforts to increase the working pressure of electrolysis and efficiency have been pursued. Research was also performed on improving the cost, efficiency and durability of Proton Exchange Membrane (PEM) hydrogen technology. Research elements focused upon PEM membranes, electrodes/catalysts, membrane-electrode assemblies, seals, bipolar plates, utilization of renewable power, reliability issues, scale, and advanced conversion topics. Additionally, direct solar-to-hydrogen conversion research to demonstrate stable and efficient photoelectrochemistry (PEC) hydrogen production systems based on a number of optional concepts was performed. Candidate PEC concepts included technical obstacles such as inefficient photocatalysis, inadequate photocurrent due to non-optimal material band gap energies, rapid electron-hole recombination, reduced hole mobility and diminished operational lifetimes of surface materials exposed to electrolytes. Project Objective 1: Design, build, operate hydrogen filling station Project Objective 2: Perform research and development for utilizing solar technologies on the hydrogen filling station and convert two utility vehicles for use by the station operators Project Objective 3: Increase capacity of hydrogen filling station; add additional vehicle; conduct safety workshop; develop a roadmap for

  20. Comparison of Body Surface Area versus Weight-Based Growth Hormone Dosing for Girls with Turner Syndrome

    NARCIS (Netherlands)

    Schrier, L.; Kam, M.L. de; McKinnon, R.; Bakri, A. Che; Oostdijk, W.; Sas, T.C.J.; Menke, L.A.; Otten, B.J.; Keizer-Schrama, S.M.; Kristrom, B.; Ankarberg-Lindgren, C.; Burggraaf, J.; Albertsson-Wikland, K.; Wit, J.M.

    2014-01-01

    Background/Aims: Growth Hormone (GH) dosage in childhood is adjusted for body size, but there is no consensus whether body weight (BW) or body surface area (BSA) should be used. We aimed at comparing the biological effect and cost-effectiveness of GH treatment dosed per m(2) BSA in comparison with d

  1. Grafting of functionalized [Fe(III)(salten)] complexes to Au(111) surfaces via thiolate groups: surface spectroscopic characterization and comparison of different linker designs.

    Science.gov (United States)

    Jacob, Hanne; Kathirvel, Ketheeswari; Petersen, Finn; Strunskus, Thomas; Bannwarth, Alexander; Meyer, Sven; Tuczek, Felix

    2013-07-01

    Functionalization of surfaces with spin crossover complexes is an intensively studied topic. Starting from dinuclear iron(III)-salten complexes [Fe(salten)(pyS)]2(BPh4)2 and [Fe(thiotolylsalten)(NCS)]2 with disulfide-containing bridging ligands, corresponding mononuclear complexes [Fe(salten)(pyS)](+) and [Fe(thiotolylsalten)(NCS)] are covalently attached to Au(111) surfaces (pySH, pyridinethiol; salten, bis(3-salicylidene-aminopropyl)amine). The adsorbed monolayers are investigated by infrared reflection absorption spectroscopy (IRRAS) in combination with X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS). Comparison of the surface vibrational spectra with bulk data allows us to draw conclusions with respect to the geometry of the adsorbed complexes. An anomaly is observed in the spectra of the surface-adsorbed monolayer of [Fe(salten)(pyS)](+), which suggests that the salten ligand is partially decoordinated from the Fe(III) center and one of its phenolate arms binds to the Au(111) surface. For complex [Fe(thiotolylsalten)(NCS)] that is bound to the Au(111) surface via a thiolate-functionalized salten ligand, this anomaly is not observed, which indicates that the coordination sphere of the complex in the bulk is retained on the surface. The implications of these results with respect to the preparation of surface-adsorbed monolayers of functional transition-metal complexes are discussed.

  2. A comparison of the uniaxial deformation of copper and nickel (1 1 19) surfaces: a molecular dynamics study

    Science.gov (United States)

    Pukšič, Nuša; Jenko, Monika; Godec, Matjaž; McGuiness, Paul J.

    2017-02-01

    While a lot is known about the deformation of metallic surfaces from experiments, elasticity theory and simulations, this investigation represents the first molecular-dynamics-based simulation of uniaxial deformation for the vicinal surfaces in a comparison of copper and nickel. These vicinal surfaces are composed of terraces divided by equidistant, mono-atomic steps. The periodicity of vicinals makes them good candidates for the study of the surface steps’ influences on surface dynamics. The simulations of tensile and compressive uniaxial deformations were performed for the (1 1 19) vicinal surfaces. Since the steps on the surfaces serve as stress concentrators, the first defects were expected to nucleate here. In the case of copper, this was found to be the case. In the case of nickel, however, dislocations nucleated beneath the near-surface layer affected by the displacement field generated by the steps. Slip was hindered at the surface step by the vortex in the displacement field. The differences in the deformation mechanisms for the Ni(1 1 19) and Cu(1 1 19) surfaces can be linked to the differences in their displacement fields. This could lead to novel bottom-up approaches to the nanostructuring of surfaces using strain.

  3. Polymer Surface Treatment by Atmospheric Pressure Low Temperature Surface Discharge Plasma:Its Characteristics and Comparison with Low Pressure Oxygen Plasma Treatment

    Institute of Scientific and Technical Information of China (English)

    Atsushi KUWABARA; Shin-ichi KURODA; Hitoshi KUBOTA

    2007-01-01

    The polymer treatment with a low-temperature plasma jet generated on the atmospheric pressure surface discharge (SD) plasma is performed.The change of the surface property over time,in comparison with low pressure oxygen (O2) plasma treatment,is examined.As one compares the treatment by atmospheric pressure plasma to that by the low pressure O2 plasma of PS (polystyrene) the treatment effects were almost in complete agreement.However,when the atmospheric pressure plasma was used for PP(polypropylene),it produced remarkable hydrophilic effects.

  4. Comparison of Analytical and Numerical Performance Predictions for a Regenerative Heat Exchanger in the International Space Station Node 3 Internal Active Thermal Control System

    Science.gov (United States)

    Wise, Stephen A.; Holt, James M.; Turner, Larry D. (Technical Monitor)

    2001-01-01

    The complexity of International Space Station (ISS) systems modeling often necessitates the concurrence of various dissimilar, parallel analysis techniques to validate modeling. This was the case with a feasibility and performance study of the ISS Node 3 Regenerative Heat Exchanger (RHX). A thermo-hydraulic network model was created and analyzed in SINDA/FLUINT. A less complex, closed form solution of the system dynamics was created using Excel. The purpose of this paper is to provide a brief description of the modeling processes utilized, the results and benefits of each to the ISS Node 3 RHX study.

  5. Comparison of Analytical and Numerical Performance Predictions for an International Space Station Node 3 Internal Active Thermal Control System Regenerative Heat Exchanger

    Science.gov (United States)

    Wise, Stephen A.; Holt, James M.

    2002-01-01

    The complexity of International Space Station (ISS) systems modeling often necessitates the concurrence of various dissimilar, parallel analysis techniques to validate modeling. This was the case with a feasibility and performance study of the ISS Node 3 Regenerative Heat Exchanger (RHX). A thermo-hydraulic network model was created and analyzed in SINDA/FLUINT. A less complex, closed form solution of the systems dynamics was created using an Excel Spreadsheet. The purpose of this paper is to provide a brief description of the modeling processes utilized, the results and benefits of each to the ISS Node 3 RHX study.

  6. Comparison of connective tissue graft and guided tissue regeneration in covering root surfaces

    Directory of Open Access Journals (Sweden)

    LotfazarM.

    2002-08-01

    Full Text Available There are many researches evaluation different methods for covering the root surface. In the most of these studies, type I and II of Miller treatment had been searched. The purpose of this study was a comparison between connective tissue graft (CTG and guided tissue regeneration (GTR with a collagen membrane in the treatment of gingival recession defects (Miller class III. Six patients, each contributing a pair of Miller class III buccal gingival recessions, were treated. The clinical measurements were obtained at baseline and 1,2,4,6,12,18 months after surgery. Statistical analysis were performed using paired t-test between periods (baseline versus 6 months and baseline versus 18 months within each treatment group and also between treatment groups before treatment and 6, 12 and 18 months after the treatment. The treatments were compared by a triple analysis of variance along the time (treatment, patient, time. Both CTG and GTR with a bioabsorbable membrane demonstrated significant clinical and esthetic improvement for gingival recession coverage. The CTG and GTR procedures had mean root coverage of 55% and 47.5% respectively, in the end of study. The CTG group was statistically better than GTR for recession depth, recession width and keratinized tissue width. Also, passing the time (18 months as a distinct factor of treatment procedures was effective in increasing of clinical attachment level and keratinized tissue width.

  7. Onset Detection in Surface Electromyographic Signals: A Systematic Comparison of Methods

    Directory of Open Access Journals (Sweden)

    Claus Flachenecker

    2001-06-01

    Full Text Available Various methods to determine the onset of the electromyographic activity which occurs in response to a stimulus have been discussed in the literature over the last decade. Due to the stochastic characteristic of the surface electromyogram (SEMG, onset detection is a challenging task, especially in weak SEMG responses. The performance of the onset detection methods were tested, mostly by comparing their automated onset estimations to the manually determined onsets found by well-trained SEMG examiners. But a systematic comparison between methods, which reveals the benefits and the drawbacks of each method compared to the other ones and shows the specific dependence of the detection accuracy on signal parameters, is still lacking. In this paper, several classical threshold-based approaches as well as some statistically optimized algorithms were tested on large samples of simulated SEMG data with well-known signal parameters. Rating between methods is performed by comparing their performance to that of a statistically optimal maximum likelihood estimator which serves as reference method. In addition, performance was evaluated on real SEMG data obtained in a reaction time experiment. Results indicate that detection behavior strongly depends on SEMG parameters, such as onset rise time, signal-to-noise ratio or background activity level. It is shown that some of the threshold-based signal-power-estimation procedures are very sensitive to signal parameters, whereas statistically optimized algorithms are generally more robust.

  8. Inversion of Land Surface Temperature (LST Using Terra ASTER Data: A Comparison of Three Algorithms

    Directory of Open Access Journals (Sweden)

    Milton Isaya Ndossi

    2016-12-01

    Full Text Available Land Surface Temperature (LST is an important measurement in studies related to the Earth surface’s processes. The Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER instrument onboard the Terra spacecraft is the currently available Thermal Infrared (TIR imaging sensor with the highest spatial resolution. This study involves the comparison of LSTs inverted from the sensor using the Split Window Algorithm (SWA, the Single Channel Algorithm (SCA and the Planck function. This study has used the National Oceanic and Atmospheric Administration’s (NOAA data to model and compare the results from the three algorithms. The data from the sensor have been processed by the Python programming language in a free and open source software package (QGIS to enable users to make use of the algorithms. The study revealed that the three algorithms are suitable for LST inversion, whereby the Planck function showed the highest level of accuracy, the SWA had moderate level of accuracy and the SCA had the least accuracy. The algorithms produced results with Root Mean Square Errors (RMSE of 2.29 K, 3.77 K and 2.88 K for the Planck function, the SCA and SWA respectively.

  9. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during July 2016 (NCEI Accession 0156399)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  10. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during July 2015 (NCEI Accession 0131976)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  11. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during August 2015 (NCEI Accession 0131989)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  12. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during October 2015 (NCEI Accession 0138228)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  13. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during August 2016 (NCEI Accession 0156623)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  14. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during November 2015 (NCEI Accession 0139551)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  15. Near-real-time surface ocean velocities derived from HF radar stations located along coastal waters of North Slope Alaska, Puerto Rico/Virgin Islands, eastern US/Gulf of Mexico, Hawaii and western US during September 2015 (NCEI Accession 0137285)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains near-real-time ocean surface velocities, also known as total vector velocities, derived from HF radar stations. The velocities are...

  16. Comparison of linear dimensional change, surface hardness and surface roughness of refractory model prepared from two different duplicating media.

    Science.gov (United States)

    Porwal, Amit; Chandrashekhar, Naveen H; Nadiger, Ramesh K; Meshramkar, Roseline D; Guttal, Satyabodh S

    2011-03-01

    The aim of this study was to evaluate and compare the linear dimensional change, surface hardness and surface roughness of the refractory casts poured against different duplicating media. Polyvinyl siloxane and Agar-agar were used for duplicating the stainless steel die. Sixty refractory models were prepared which were divided into two groups: I and II with 30 samples each respectively. Each group was subdivided into 3 subgroups with 10 samples each which were treated differently. All the specimens were measured for the linear dimensional change and surface hardness and the obtained data was statistically analyzed. Surface roughness was evaluated qualitatively taking SEM photomicrographs. Statistical analysis of linear dimensional change using one-way ANOVA showed statistically significant difference between subgroups of group I and non-significant difference between subgroups of group II. One-way ANOVA for Brinell hardness number showed statistically significant difference between the subgroups of group I & II. Student's 't' test results for linear dimensional change among different subgroups of group I & II showed significant difference between IA-IIA, IB-IIB, IC-IIC. Similarly 't'-test results for Brinell hardness number showed significant difference between subgroups IA-IIA, IB-IIB, and IC-IIC. Surface characteristics of the refractory casts poured against polyvinyl siloxane duplicating media were found to be better than the Agar media.

  17. COMPARISON OF ANN WITH RSM IN PREDICTING SURFACE ROUGHNESS WITH RESPECT TO PROCESS PARAMETERS IN Nd: YAG LASER DRILLING

    Directory of Open Access Journals (Sweden)

    ARINDAM MAJUMDER

    2010-10-01

    Full Text Available Micro machining is a ready solution towards the miniaturization of component and devices. The process parameters of low power pulse Nd:YAG laser machining such as pulse rate, pulse width, speed play a major role in deciding the surface quality. Two methods, response surface methodology (RSM and artificial neural network (ANN were used to predict the surface roughness of Nd:YAG laser drilled mild steel specimens. The experiments were conducted based on the three factors, three levels and central composite face centered design with full replication technique and mathematical model was developed. Also a comparison has been done with between the result obtained throughresponse surface methodology (RSM and artificial neural network (ANN.

  18. Comparison of hole surface finishing processes with roller burnishing method applied in copper materials

    OpenAIRE

    Adnan AKKURT; Kurt, Abdullah; Ahmet ÖZDEMİR; ŞEKER, Ulvi

    2014-01-01

    Surface finishing processes such as drilling, turning, reaming, grinding, honing and roller burnishing etc. are widely used in manufacturing as hole surface finishing process. In addition to the characteristics of hole such as the surface roughness, the surface hardness and the wear resistance, the circularity and cylindricality of hole are also effective on the performance of hole. In this paper, it is presented that different hole surface finishing processes were applied to the samples made...

  19. Comparison of waxy and normal potato starch remaining granules after chemical surface gelatinization: Pasting behavior and surface morphology

    NARCIS (Netherlands)

    Huang, J.; Chen Zenghong,; Xu, Yalun; Li, Hongliang; Liu, Shuxing; Yang, Daqing; Schols, H.A.

    2014-01-01

    o understand the contribution of granule inner portion to the pasting property of starch, waxy potato starch and two normal potato starches and their acetylated starch samples were subjected to chemical surface gelatinization by 3.8 mol/L CaCl2 to obtain remaining granules. Native and acetylated, or

  20. Comparison of waxy and normal potato starch remaining granules after chemical surface gelatinization: Pasting behavior and surface morphology

    NARCIS (Netherlands)

    Huang, J.; Chen Zenghong,; Xu, Yalun; Li, Hongliang; Liu, Shuxing; Yang, Daqing; Schols, H.A.

    2014-01-01

    o understand the contribution of granule inner portion to the pasting property of starch, waxy potato starch and two normal potato starches and their acetylated starch samples were subjected to chemical surface gelatinization by 3.8 mol/L CaCl2 to obtain remaining granules. Native and acetylated,

  1. Comparison of surface-based and image-based quality metrics for the analysis of dimensional computed tomography data

    Directory of Open Access Journals (Sweden)

    Francisco A. Arenhart

    2016-11-01

    Full Text Available This paper presents a comparison of surface-based and image-based quality metrics for dimensional X-ray computed tomography (CT data. The chosen metrics are used to characterize two key aspects in acquiring signals with CT systems: the loss of information (blurring and the adding of unwanted information (noise. A set of structured experiments was designed to test the response of the metrics to different influencing factors. It is demonstrated that, under certain circumstances, the results of both types of metrics become conflicting, emphasizing the importance of using surface information for evaluating the quality dimensional CT data. Specific findings using both types of metrics are also discussed.

  2. Comparison of root water uptake modules using either the surface energy balance or potential transpiration

    Science.gov (United States)

    Braud, Isabelle; Varado, Noémie; Olioso, Albert

    2005-01-01

    Numerical models simulating changes in soil water content with time rely on accurate estimation of root water uptake. This paper considers two root water uptake modules that have a compensation mechanism allowing for increased root uptake under conditions of water stress. These modules, proposed by Lai and Katul and Li et al. [Adv. Water Resour. 23 (2000) 427 and J. Hydrol. 252 (2001) 189] use potential transpiration weighted, for each soil layer, by a water stress and a compensation function in order to estimate actual transpiration. The first objective of the paper was to assess the accuracy of the proposed root extraction modules against two existing data sets, acquired under dry conditions for a winter wheat and a soybean crop. In order to perform a fair comparison, both modules were included as possible root water extraction modules within the Simple Soil Plant Atmosphere Transfer (SiSPAT) model. In this first set of simulations, actual transpiration was calculated using the solution of the surface energy budget as implemented in the SiSPAT model. Under such conditions, both root extraction modules were able to reproduce accurately the time evolution of soil moisture at various depths, soil water storage and daily evaporation. Results were generally improved when we activated the compensation mechanisms. However, we showed that Lai and Katul [Adv. Water Resour. 23 (2000) 427] module was sensitive to soil hydraulic properties through its water stress function, whereas the Li et al. [J. Hydrol. 252 (2001) 189] module was not very sensitive to the specification of its parameter. The latter module is therefore recommended for inclusion into a larger scale hydrological model, due to its robustness. When water balance models are run at larger scales or on areas with scarce data, actual transpiration is often calculated using models based on potential transpiration without solving the surface energy balance. The second objective of the paper was to assess the loss of

  3. Application of Kalman filtering in monitoring of surface subsidence by the observation station%Kalman滤波在地表移动观测站沉降监测中的应用研究

    Institute of Scientific and Technical Information of China (English)

    吕伟才; 秦永洋; 孙兴平; 郭红星

    2011-01-01

    According to Kalman filtering theory and the needs of mining subsidence monitoring, the standard Kalman filtering model and predicting model of the surface subsidence are advanced which is monitored by the surface displacement observation station. These models are tested by the data from the 1117(1) First Exploiting Face Observation Station in Guqiao Mine, and meet the requirement for mining subsidence management engineering.%文章根据Kalman滤波理论,结合矿区开采沉陷监测的需要,建立了对地表移动观测站沉降监测进行动态处理的标准Kalman滤波模型和预测预报模型;利用顾桥矿1117(1)首采面观测站的实测资料,对所建立的滤波模型和预测预报模型进行了检核,结果表明所建模型基本能满足开采沉陷工程治理的要求.

  4. Comparison of Surface Elevation Changes of the Greenland and Antarctic Ice Sheets from Radar and Laser Altimetry

    Science.gov (United States)

    Zwally, H. Jay; Brenner, Anita C.; Barbieri, Kristine; DiMarzio, John P.; Li, Jun; Robbins, John; Saba, Jack L.; Yi, Donghui

    2012-01-01

    A primary purpose of satellite altimeter measurements is determination of the mass balances of the Greenland and Antarctic ice sheets and changes with time by measurement of changes in the surface elevations. Since the early 1990's, important measurements for this purpose have been made by radar altimeters on ERS-l and 2, Envisat, and CryoSat and a laser altimeter on ICESat. One principal factor limiting direct comparisons between radar and laser measurements is the variable penetration depth of the radar signal and the corresponding location of the effective depth of the radar-measured elevation beneath the surface, in contrast to the laser-measured surface elevation. Although the radar penetration depth varies significantly both spatially and temporally, empirical corrections have been developed to account for this effect. Another limiting factor in direct comparisons is caused by differences in the size of the laser and radar footprints and their respective horizontal locations on the surface. Nevertheless, derived changes in elevation, dHldt, and time-series of elevation, H(t), have been shown to be comparable. For comparisons at different times, corrections for elevation changes caused by variations in the rate offrrn compaction have also been developed. Comparisons between the H(t) and the average dH/dt at some specific locations, such as the Vostok region of East Antarctic, show good agreement among results from ERS-l and 2, Envisat, and ICESat. However, Greenland maps of dHidt from Envisat and ICESat for the same time periods (2003-2008) show some areas of significant differences as well as areas of good agreement. Possible causes of residual differences are investigated and described.

  5. Methane emissions from natural gas compressor stations in the transmission and storage sector: measurements and comparisons with the EPA greenhouse gas reporting program protocol.

    Science.gov (United States)

    Subramanian, R; Williams, Laurie L; Vaughn, Timothy L; Zimmerle, Daniel; Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Floerchinger, Cody; Tkacik, Daniel S; Mitchell, Austin L; Sullivan, Melissa R; Dallmann, Timothy R; Robinson, Allen L

    2015-03-03

    Equipment- and site-level methane emissions from 45 compressor stations in the transmission and storage (T&S) sector of the US natural gas system were measured, including 25 sites required to report under the EPA greenhouse gas reporting program (GHGRP). Direct measurements of fugitive and vented sources were combined with AP-42-based exhaust emission factors (for operating reciprocating engines and turbines) to produce a study onsite estimate. Site-level methane emissions were also concurrently measured with downwind-tracer-flux techniques. At most sites, these two independent estimates agreed within experimental uncertainty. Site-level methane emissions varied from 2-880 SCFM. Compressor vents, leaky isolation valves, reciprocating engine exhaust, and equipment leaks were major sources, and substantial emissions were observed at both operating and standby compressor stations. The site-level methane emission rates were highly skewed; the highest emitting 10% of sites (including two superemitters) contributed 50% of the aggregate methane emissions, while the lowest emitting 50% of sites contributed less than 10% of the aggregate emissions. Excluding the two superemitters, study-average methane emissions from compressor housings and noncompressor sources are comparable to or lower than the corresponding effective emission factors used in the EPA greenhouse gas inventory. If the two superemitters are included in the analysis, then the average emission factors based on this study could exceed the EPA greenhouse gas inventory emission factors, which highlights the potentially important contribution of superemitters to national emissions. However, quantification of their influence requires knowledge of the magnitude and frequency of superemitters across the entire T&S sector. Only 38% of the methane emissions measured by the comprehensive onsite measurements were reportable under the new EPA GHGRP because of a combination of inaccurate emission factors for leakers and

  6. Forecasting Daily Precipitation Using Hybrid Model of Wavelet-Artificial Neural Network and Comparison with Adaptive Neurofuzzy Inference System (Case Study: Verayneh Station, Nahavand

    Directory of Open Access Journals (Sweden)

    Abazar Solgi

    2014-01-01

    Full Text Available Doubtlessly the first step in a river management is the precipitation modeling over the related watershed. However, considering high-stochastic property of the process, many models are still being developed in order to define such a complex phenomenon in the field of hydrologic engineering. Recently artificial neural network (ANN as a nonlinear interextrapolator is extensively used by hydrologists for precipitation modeling as well as other fields of hydrology. In the present study, wavelet analysis combined with artificial neural network and finally was compared with adaptive neurofuzzy system to predict the precipitation in Verayneh station, Nahavand, Hamedan, Iran. For this purpose, the original time series using wavelet theory decomposed to multiple subtime series. Then, these subseries were applied as input data for artificial neural network, to predict daily precipitation, and compared with results of adaptive neurofuzzy system. The results showed that the combination of wavelet models and neural networks has a better performance than adaptive neurofuzzy system, and can be applied to predict both short- and long-term precipitations.

  7. Observation of an Aligned Gas - Solid "Eutectic" during Controlled Directional Solidification Aboard the International Space Station - Comparison with Ground-based Studies

    Science.gov (United States)

    Grugel, R. N.; Anilkumar, A.

    2005-01-01

    Direct observation of the controlled melting and solidification of succinonitrile was conducted in the glovebox facility of the International Space Station (ISS). The experimental samples were prepared on ground by filling glass tubes, 1 cm ID and approximately 30 cm in length, with pure succinonitrile (SCN) in an atmosphere of nitrogen at 450 millibar pressure for eventual processing in the Pore Formation and Mobility Investigation (PFMI) apparatus in the glovebox facility (GBX) on board the ISS. Real time visualization during controlled directional melt back of the sample showed nitrogen bubbles emerging from the interface and moving through the liquid up the imposed temperature gradient. Over a period of time these bubbles disappear by dissolving into the melt. Translation is stopped after melting back of about 9 cm of the sample, with an equilibrium solid-liquid interface established. During controlled re-solidification, aligned tubes of gas were seen growing perpendicular to the planar solid/liquid interface, inferring that the nitrogen previously dissolved into the liquid SCN was now coming out at the solid/liquid interface and forming the little studied liquid = solid + gas eutectic-type reaction. The observed structure is evaluated in terms of spacing dimensions, interface undercooling, and mechanisms for spacing adjustments. Finally, the significance of processing in a microgravity environment is ascertained in view of ground-based results.

  8. Comparisons of Limit Analysis Solutions and Random Search Solutions on Slope Critical Slip SUrface

    Institute of Scientific and Technical Information of China (English)

    JianfengWANG

    1998-01-01

    The object of this paper is twofold:to present a kinematics limit analysis for assessing the safety of slope or its critical slip surface,and to compare the searched slip surface with that by limit analysis.

  9. Comparison of MTI and Ground Truth Sea Surface Temperatures at Nauru

    Energy Technology Data Exchange (ETDEWEB)

    Kurzeja, R.

    2002-09-05

    This report evaluates MTI-derived surface water temperature near the tropical Pacific island of Nauru. The MTI sea-surface temperatures were determined by the Los Alamos National Laboratory based on the robust retrieval.

  10. Recharge and discharge of near-surface groundwater in Forsmark. Comparison of classification methods

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Kent [Golder Associates AB, Uppsala (Sweden); Johansson, Per-Olof [Artesia Grundvattenkonsult AB, Taeby (Sweden); Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden); Bosson, Emma; Berglund, Sten [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2007-03-15

    This report presents and compares data and models for identification of near-surface groundwater recharge and discharge (RD) areas in Forsmark. The general principles of groundwater recharge and discharge are demonstrated and applied to interpret hydrological and hydrogeological observations made in the Forsmark area. 'Continuous' RD classification methods considered in the study include topographical modelling, map overlays, and hydrological-hydrogeological flow modelling. 'Discrete' (point) methods include field-based and hydrochemistry-based RD classifications of groundwater monitoring well locations. The topographical RD modelling uses the digital elevation model as the only input. The map overlays use background maps of Quaternary deposits, soils, and ground- and field layers of the vegetation/land use map. Further, the hydrological-hydrogeological modelling is performed using the MIKE SHE-MIKE 11 software packages, taking into account e.g. topography, meteorology, hydrogeology, and geometry of watercourses and lakes. The best between-model agreement is found for the topography-based model and the MIKE SHE-MIKE 11 model. The agreement between the topographical model and the map overlays is less good. The agreement between the map overlays on the one hand, and the MIKE SHE and field-based RD classifications on the other, is thought to be less good, as inferred from the comparison made with the topography-based model. However, much improvement of the map overlays can likely be obtained, e.g. by using 'weights' and calibration (such exercises were outside the scope of the present study). For field-classified 'recharge wells', there is a good agreement to the hydrochemistry-based (Piper plot) well classification, but less good for the field-classified 'discharge wells'. In addition, the concentration of the age-dating parameter tritium shows low variability among recharge wells, but a large spread among discharge

  11. Comparison of 3 methods on fabricating micro- /nano- structured surface on 3D mold cavity

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; Bissacco, Giuliano

    2015-01-01

    The methods to manufacture micro- or nano- structures on surfaces have been an area of intense investigation. Demands are shown for technologies for surface structuring on real 3D parts in many fields. However, most technologies for the fabrication of micro-structured functional surfaces are stil...

  12. Growth of In x Ga1-x Sb alloy semiconductor at the International Space Station (ISS) and comparison with terrestrial experiments.

    Science.gov (United States)

    Inatomi, Y; Sakata, K; Arivanandhan, M; Rajesh, G; Nirmal Kumar, V; Koyama, T; Momose, Y; Ozawa, T; Okano, Y; Hayakawa, Y

    2015-01-01

    In x Ga1-x Sb is an important material that has tunable properties in the infrared (IR) region and is suitable for IR-device applications. Since the quality of crystals relies on growth conditions, the growth process of alloy semiconductors can be examined better under microgravity (μG) conditions where convection is suppressed. To investigate the dissolution and growth process of In x Ga1-x Sb alloy semiconductors via a sandwiched structure of GaSb(seed)/InSb/GaSb(feed) under normal and μG conditions. In x Ga1-x Sb crystals were grown at the International Space Station (ISS) under μG conditions, and a similar experiment was conducted under terrestrial conditions (1G) using the vertical gradient freezing (VGF) method. The grown crystals were cut along the growth direction and its growth properties were studied. The indium composition and growth rate of grown crystals were calculated. The shape of the growth interface was nearly flat under μG, whereas under 1G, it was highly concave with the initial seed interface being nearly flat and having facets at the peripheries. The quality of the μG crystals was better than that of the 1G samples, as the etch pit density was low in the μG sample. The growth rate was higher under μG compared with 1G. Moreover, the growth started at the peripheries under 1G, whereas it started throughout the seed interface under μG. Kinetics played a dominant role under 1G. The suppressed convection under μG affected the dissolution and growth process of the In x Ga1-x Sb alloy semiconductor.

  13. Evaluation of a main steam line break with induced, multiple tube ruptures: A comparison of NUREG 1477 (Draft) and transient methodologies Palo Verde Nuclear Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Parrish, K.R.

    1995-09-01

    This paper presents the approach taken to analyze the radiological consequences of a postulated main steam line break event, with one or more tube ruptures, for the Palo Verde Nuclear Generating Station. The analysis was required to support the restart of PVNGS Unit 2 following the steam generator tube rupture event on March 14, 1993 and to justify continued operation of Units 1 and 3. During the post-event evaluation, the NRC expressed concern that Unit 2 could have been operating with degraded tubes and that similar conditions could exist in Units 1 and 3. The NRC therefore directed that a safety assessment be performed to evaluate a worst case scenario in which a non-isolable main steam line break occurs inducing one or more tube failures in the faulted steam generator. This assessment was to use the generic approach described in NUREG 1477, Voltage-Based Interim Plugging Criteria for Steam Generator Tubes - Task Group Report. An analysis based on the NUREG approach was performed but produced unacceptable results for off-site and control room thyroid doses. The NUREG methodology, however, does not account for plant thermal-hydraulic transient effects, system performance, or operator actions which could be credited to mitigate dose consequences. To deal with these issues, a more detailed analysis methodology was developed using a modified version of the Combustion Engineering Plant Analysis Code, which examines the dose consequences for a main steam line break transient with induced tube failures for a spectrum equivalent to 1 to 4 double ended guillotine U-tube breaks. By incorporating transient plant system responses and operator actions, the analysis demonstrates that the off-site and control room does consequences for a MSLBGTR can be reduced to acceptable limits. This analysis, in combination with other corrective and recovery actions, provided sufficient justification for continued operation of PVNGS Units 1 and 3, and for the subsequent restart of Unit 2.

  14. Growth of InxGa1−xSb alloy semiconductor at the International Space Station (ISS) and comparison with terrestrial experiments

    Science.gov (United States)

    Inatomi, Y; Sakata, K; Arivanandhan, M; Rajesh, G; Nirmal Kumar, V; Koyama, T; Momose, Y; Ozawa, T; Okano, Y; Hayakawa, Y

    2015-01-01

    Background: InxGa1−xSb is an important material that has tunable properties in the infrared (IR) region and is suitable for IR-device applications. Since the quality of crystals relies on growth conditions, the growth process of alloy semiconductors can be examined better under microgravity (μG) conditions where convection is suppressed. Aims: To investigate the dissolution and growth process of InxGa1−xSb alloy semiconductors via a sandwiched structure of GaSb(seed)/InSb/GaSb(feed) under normal and μG conditions. Methods: InxGa1−xSb crystals were grown at the International Space Station (ISS) under μG conditions, and a similar experiment was conducted under terrestrial conditions (1G) using the vertical gradient freezing (VGF) method. The grown crystals were cut along the growth direction and its growth properties were studied. The indium composition and growth rate of grown crystals were calculated. Results: The shape of the growth interface was nearly flat under μG, whereas under 1G, it was highly concave with the initial seed interface being nearly flat and having facets at the peripheries. The quality of the μG crystals was better than that of the 1G samples, as the etch pit density was low in the μG sample. The growth rate was higher under μG compared with 1G. Moreover, the growth started at the peripheries under 1G, whereas it started throughout the seed interface under μG. Conclusions: Kinetics played a dominant role under 1G. The suppressed convection under μG affected the dissolution and growth process of the InxGa1−xSb alloy semiconductor. PMID:28725715

  15. Fire Stations - 2007

    Data.gov (United States)

    Kansas Data Access and Support Center — Fire Station Locations in Kansas Any location where fire fighters are stationed at or based out of, or where equipment that such personnel use in carrying out their...

  16. Big Game Reporting Stations

    Data.gov (United States)

    Vermont Center for Geographic Information — Point locations of big game reporting stations. Big game reporting stations are places where hunters can legally report harvested deer, bear, or turkey. These are...

  17. Water Level Station History

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Images contain station history information for 175 stations in the National Water Level Observation Network (NWLON). The NWLON is a network of long-term,...

  18. Streamflow Gaging Stations

    Data.gov (United States)

    Department of Homeland Security — This map layer shows selected streamflow gaging stations of the United States, Puerto Rico, and the U.S. Virgin Islands, in 2013. Gaging stations, or gages, measure...

  19. Hammond Bay Biological Station

    Data.gov (United States)

    Federal Laboratory Consortium — Hammond Bay Biological Station (HBBS), located near Millersburg, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). HBBS was established by...

  20. Fire Stations - 2009

    Data.gov (United States)

    Kansas Data Access and Support Center — Fire Stations in Kansas Any location where fire fighters are stationed or based out of, or where equipment that such personnel use in carrying out their jobs is...

  1. Capacity at Railway Stations

    DEFF Research Database (Denmark)

    Landex, Alex

    2011-01-01

    Stations do have other challenges regarding capacity than open lines as it is here the traffic is dispatched. The UIC 406 capacity method that can be used to analyse the capacity consumption can be exposed in different ways at stations which may lead to different results. Therefore, stations need...... special focus when conducting UIC 406 capacity analyses.This paper describes how the UIC 406 capacity method can be expounded for stations. Commonly for the analyses of the stations it is recommended to include the entire station including the switch zone(s) and all station tracks. By including the switch...... is changed, this paper recommends that the railway lines are not always be divided. In case trains turn around on open (single track) line, the capacity consumption may be too low if a railway line is divided. The same can be the case if only few trains are overtaken at an overtaking station. For dead end...

  2. Weather Radar Stations

    Data.gov (United States)

    Department of Homeland Security — These data represent Next-Generation Radar (NEXRAD) and Terminal Doppler Weather Radar (TDWR) weather radar stations within the US. The NEXRAD radar stations are...

  3. Reference Climatological Stations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Reference Climatological Stations (RCS) network represents the first effort by NOAA to create and maintain a nationwide network of stations located only in areas...

  4. Newport Research Station

    Data.gov (United States)

    Federal Laboratory Consortium — The Newport Research Station is the Center's only ocean-port research facility. This station is located at Oregon State University's Hatfield Marine Science Center,...

  5. Station Climatic Summaries, Asia

    Science.gov (United States)

    1989-07-01

    OCDS) ................................................... 077 BIRJAND 408090 8612 (OCDS) ............................................. ( 381 BUSHEHR...ALL HOURS # 2 1 0 1 0 # 0 # 1 # 1 1 CACECR-IB 080 OPERATIONAL CLIMATIC DATA SUMM ARY STATION: BIRJAND , IRAN STATION #: 408090 ICAO ID...082. L@ OPERATIONAL CLIMATIC DATA SIJ44ARY STATION: BIRJAND , IRAN STATION #: 408090 ICAO ID: OIMB LOCATION: 32054’N, 59016’E ELEVATION (FEET): 4823 LST

  6. Comparison of waxy and normal potato starch remaining granules after chemical surface gelatinization: pasting behavior and surface morphology.

    Science.gov (United States)

    Huang, Junrong; Chen, Zhenghong; Xu, Yalun; Li, Hongliang; Liu, Shuxing; Yang, Daqing; Schols, Henk A

    2014-02-15

    To understand the contribution of granule inner portion to the pasting property of starch, waxy potato starch and two normal potato starches and their acetylated starch samples were subjected to chemical surface gelatinization by 3.8 mol/L CaCl2 to obtain remaining granules. Native and acetylated, original and remaining granules of waxy potato starch had similar rapid visco analyzer (RVA) pasting profiles, while those of two normal potato starches behaved obviously different from each other. All remaining granules had lower peak viscosity than the corresponding original granules. Contribution of waxy potato starch granule's inner portion to the peak viscosity was significant more than those of normal potato starches. The shell structure appearing on the remaining granule surface for waxy potato starch was smoother and thinner than that for normal potato starches as observed by scanning electron microscopy, indicating a more regular structure of shell and a more ordered packing of shell for waxy potato starch granules. The blocklet size of waxy potato starch was smaller and more uniform than those of normal potato starches as shown by atomic force microscopy images of original and remaining granules. In general, our results provided the evidence for the spatial structure diversity between waxy and normal potato starch granules: outer layer and inner portion of waxy potato starch granule had similar structure, while outer layer had notably different structure from inner portion for normal potato starch granule.

  7. Simulation of land surface temperatures: comparison of two climate models and satellite retrievals

    Directory of Open Access Journals (Sweden)

    J. M. Edwards

    2009-03-01

    Full Text Available Recently there has been significant progress in the retrieval of land surface temperature from satellite observations. Satellite retrievals of surface temperature offer several advantages, including broad spatial coverage, and such data are potentially of great value in assessing general circulation models of the atmosphere. Here, retrievals of the land surface temperature over the contiguous United States are compared with simulations from two climate models. The models generally simulate the diurnal range realistically, but show significant warm biases during the summer. The models' diurnal cycle of surface temperature is related to their surface flux budgets. Differences in the diurnal cycle of the surface flux budget between the models are found to be more pronounced than those in the diurnal cycle of surface temperature.

  8. Comparison between earthquake magnitudes determined by China seismograph network and US seismograph network (Ⅱ):Surface wave magnitude

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    By using orthogonal regression method, a systematic comparison is made between surface wave magnitudes determined by Institute of Geophysics of China Earthquake Administration (IGCEA) and National Earthquake Information Center of US Geological Survey (USGS/NEIC) on the basis of observation data collected by the two institutions between 1983 and 2004. A formula is obtained which reveals the relationship between surface wave magnitudes determined by China seismograph network and US seismograph network. The result shows that, as different calculation formulae and observational instruments are used, surface wave magnitude determined by IGCEA is generally greater by 0.2 than that determined by NEIC: for M=3.5~4.5 earthquakes, it is greater by 0.3;for M=5.0~6.5 earthquakes, it is greater by 0.2;and for M≥7.0 earthquakes, it is greater by no more than 0.1.

  9. The effects of contamination from silicones and a modified-tefzel® insulation on critical surfaces of the international space station

    Science.gov (United States)

    Babel, Henry W.; Hasegawa, Mark; Jones, Cherie; Fussell, John

    1997-01-01

    The purpose of this study was to assess the contamination resulting from extensive usage of silicone-insulated and modified Tefzel-insulated electrical cables and a silicone-based thermal control coating, S-13GP/LO-1, used on the International Space Station (ISS). The outgassing condensation rates of these materials were characterized per ASTM 1559-93 as a function of contamination source and receiver hardware temperatures. The results of MOLFLUX analyses for both the silicone-insulated cables and the silicone-based thermal control coating showed that these materials did not meet the program requirements. The silicone-insulated cables and the antenna and associated hardware painted with S-13GP/LO-1 were vacuum baked and the outgassing condensation rates remeasured. These products now met the program requirements. The condensable portion of the outgassed products from modified-Tefzel cable insulation at two temperatures was deposited onto the white, inorganic thermal control coating, Z-93P. These contaminants were exposed to various space environments that included near ultraviolet (UV) radiation, vacuum UV (VUV) radiation, and atomic oxygen (AO). The contaminant darkened more rapidly with VUV exposure than a silicone contaminant of the same thickness. It was eroded by AO and bleached in air after VUV. It was shown that the ISS hardware provided would perform satisfactorily.

  10. Seasonal variability of surface and column carbon monoxide over the megacity Paris, high-altitude Jungfraujoch and Southern Hemispheric Wollongong stations

    Science.gov (United States)

    Té, Yao; Jeseck, Pascal; Franco, Bruno; Mahieu, Emmanuel; Jones, Nicholas; Paton-Walsh, Clare; Griffith, David W. T.; Buchholz, Rebecca R.; Hadji-Lazaro, Juliette; Hurtmans, Daniel; Janssen, Christof

    2016-09-01

    This paper studies the seasonal variation of surface and column CO at three different sites (Paris, Jungfraujoch and Wollongong), with an emphasis on establishing a link between the CO vertical distribution and the nature of CO emission sources. We find the first evidence of a time lag between surface and free tropospheric CO seasonal variations in the Northern Hemisphere. The CO seasonal variability obtained from the total columns and free tropospheric partial columns shows a maximum around March-April and a minimum around September-October in the Northern Hemisphere (Paris and Jungfraujoch). In the Southern Hemisphere (Wollongong) this seasonal variability is shifted by about 6 months. Satellite observations by the IASI-MetOp (Infrared Atmospheric Sounding Interferometer) and MOPITT (Measurements Of Pollution In The Troposphere) instruments confirm this seasonality. Ground-based FTIR (Fourier transform infrared) measurements provide useful complementary information due to good sensitivity in the boundary layer. In situ surface measurements of CO volume mixing ratios at the Paris and Jungfraujoch sites reveal a time lag of the near-surface seasonal variability of about 2 months with respect to the total column variability at the same sites. The chemical transport model GEOS-Chem (Goddard Earth Observing System chemical transport model) is employed to interpret our observations. GEOS-Chem sensitivity runs identify the emission sources influencing the seasonal variation of CO. At both Paris and Jungfraujoch, the surface seasonality is mainly driven by anthropogenic emissions, while the total column seasonality is also controlled by air masses transported from distant sources. At Wollongong, where the CO seasonality is mainly affected by biomass burning, no time shift is observed between surface measurements and total column data.

  11. Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

    Energy Technology Data Exchange (ETDEWEB)

    Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Rytlewski, Piotr [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, ul. M. Skłodowskiej–Curie 55, 87-100 Toruń (Poland); Żenkiewicz, Marian [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland)

    2015-08-15

    Highlights: • We modified polylactide surface layer with chemical, plasma or laser methods. • We tested selected properties and surface structure of modified samples. • We stated that the plasma treatment appears to be the most beneficial. - Abstract: The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm{sup 2} was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

  12. Comparação microclimática de ambiente de várzea e de posto meteorológico Microclimatic comparison of the environment of weather station and floodplains

    Directory of Open Access Journals (Sweden)

    Andrew Patrick Ciarelli Brunini

    2004-01-01

    compared by paired comparison analysis, for the months from October to March (representing spring and summer conditions and the months from April to July (representing autumn and winter conditions.The evapotranspiration in the daily scale was estimated by the Penman-Monteith method adopted by FAO. During the autumn-winter (O-I period, in the floodplain, it was observed that the average maximum air temperature were 0.1ºC and the minimum air temperature was found to be 3.4ºC lower than the weather station environment. During autumn-winter period the maximum temperatures, at the floodplain, were 0,9 ºC higher than the standard weather conditions. Considering the evapotranspiration in the spring/summer period, the values in the two conditions analyzed (station vs. floodplain were very similar. Evapotranspiration in both environments varied between 1.0 and 7.8 mm/day with maximum values occurring during the October/November period. On the other hand, the estimates made during the autumn/winter period for the weather station were higher, than those made for the floodplain. In the autumn/winter period the evapotranspiration estimated for the station were mostly superior( 1.6 mm/day to those of the floodplain. During the autumn/winter period the differences between the environment of flood plains and weather station were higher showing that for the floodplains the microclimatic parameters are more extreme than for the weather station.

  13. Integrating stations from the North America Gravity Database into a local GPS-based land gravity survey

    Science.gov (United States)

    Shoberg, Thomas G.; Stoddard, Paul R.

    2013-01-01

    The ability to augment local gravity surveys with additional gravity stations from easily accessible national databases can greatly increase the areal coverage and spatial resolution of a survey. It is, however, necessary to integrate such data seamlessly with the local survey. One challenge to overcome in integrating data from national databases is that these data are typically of unknown quality. This study presents a procedure for the evaluation and seamless integration of gravity data of unknown quality from a national database with data from a local Global Positioning System (GPS)-based survey. The starting components include the latitude, longitude, elevation and observed gravity at each station location. Interpolated surfaces of the complete Bouguer anomaly are used as a means of quality control and comparison. The result is an integrated dataset of varying quality with many stations having GPS accuracy and other reliable stations of unknown origin, yielding a wider coverage and greater spatial resolution than either survey alone.

  14. Comparison of time-dependent changes in the surface hardness of different composite resins

    OpenAIRE

    Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

    2013-01-01

    Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples wer...

  15. Quantitative comparisons of radar image, scatterometer, and surface roughness data from Pisgah Crater, CA

    Science.gov (United States)

    Farr, T. G.; Engheta, N.

    1983-01-01

    The relationships between radar image brightness and backscatter coefficient, between the backscatter coefficient and surface roughness, and between surface roughness and geology, must be established in order to satisfy criteria for the quantitative use of radar images. Attention is presently given to the merits of calibrated radar images and scatterometers as sources of the backscatter coefficient, theories that yield the coefficient on the basis of known surface roughness (and vice versa), and the geologic interpretation of surface roughness and backscatter signatures. These considerations are discussed in the case of the Pisgah Crater and lava field in the Mojave Desert of California.

  16. Seasonal variation of near surface black carbon and satellite derived vertical distribution of aerosols over a semi-arid station in India

    Science.gov (United States)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Shaik, Nazeer Hussain; Maraka, Vasudeva Reddy; Rajuru, Ramakrishna Reddy; Surendran Nair, Suresh Babu

    2017-02-01

    Extensive measurements of aerosol black carbon mass concentration (BC) and vertical profiles of atmospheric aerosols have been carried out using Aethalometer and CALIPSO level - 2 satellite data from December 2012 to November 2014 over a semi-arid station, Anantapur. We found a bimodal distribution in the mass concentrations of BC aerosols on a diurnal scale. A sharp peak was observed during morning rush hours (7:00 to 8:00 LT) almost an hour after the local sunrise. After which, a broad nocturnal peak was found during 21:00 to 22:00 LT. The seasonal mean BC concentrations (Mixed layer height (ML)) were found to be 3.45 ± 1.44 μg/m3 (676 ± 117 m), 2.55 ± 0.85 μg/m3 (1215 ± 190 m), 1.22 ± 0.31 μg/m3 (1134 ± 194 m) and 1.75 ± 0.70 μg/m3 (612 ± 135 m), during the winter, summer, monsoon and post-monsoon respectively. The vertical profiles of aerosol extinction coefficient and back scattering ratio profiles were derived from Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) showed a strong seasonal variation with aerosols mostly confined below 2 km during the post-monsoon and winter seasons whereas in the other two seasons, the aerosol layer expands beyond 6 km. Depolarization ratios (> 0.2) are higher during summer and monsoon at higher altitude regions demonstrate the presence of dust particles, which contribute to the large aerosol extinction at higher levels. These results are further supported by the backward trajectory cluster analysis.

  17. 1997–2007 CO trend at the high Alpine site Jungfraujoch: a comparison between NDIR surface in situ and FTIR remote sensing observations

    Directory of Open Access Journals (Sweden)

    B. Dils

    2011-07-01

    Full Text Available Within the atmospheric research community, there is a strong interest in integrated datasets, combining data from several instrumentations. This integration is complicated by the different characteristics of the datasets, inherent to the measurement techniques. Here we have compared two carbon monoxide time series (1997 till 2007 acquired at the high-Alpine research station Jungfraujoch (3580 m above sea level, with two well-established measurement techniques, namely in situ surface concentration measurements using Non-Dispersive Infrared Absorption technology (NDIR, and ground-based remote sensing measurements using solar absorption Fourier Transform Infrared spectrometry (FTIR. The profile information available in the FTIR signal allowed us to extract an independent layer with a top height of 7.18 km above sea level, appropriate for comparison with our in situ measurements. We show that, even if both techniques are able to measure free troposphere CO concentrations, the datasets exhibit marked differences in their overall trends (−3.21 ± 0.03 ppb year−1 for NDIR vs. −0.8 ± 0.4 ppb year−1 for FTIR. Removing measurements that are polluted by uprising boundary layer air has a strong impact on the NDIR trend (now −2.62 ± 0.03 ppb year−1, but its difference with FTIR remains significant. Using the LAGRANTO trajectory model, we show that both measurement techniques are influenced by different source regions and therefore are likely subject to exhibit significant differences in their overall trend behaviour. However the observation that the NDIR-FTIR trend difference is as significant before as after 2001 is at odds with available emission databases which claim a significant Asian CO increase after 2001 only.

  18. The icephobicity comparison of polysiloxane modified hydrophobic and superhydrophobic surfaces under condensing environments

    Science.gov (United States)

    Wang, Yuanyi; Liu, Jun; Li, Mingzhen; Wang, Qingjun; Chen, Qingmin

    2016-11-01

    Four polydimethylsiloxane (PDMS) coatings with different surface free energies have been prepared and applied to smooth and roughened aluminum plates to form hydrophobic and superhydrophobic surfaces. Their surface wettability in terms of water contact angle (CA), sliding angle (SA) and water droplet impact dynamics was studied under an ambient (50% relative humidity, RH at 25 °C) and three different condensing environments (low, highly and extremely condensing, i.e. 30%, 60% and 90% RH at -10 °C). In addition, the surface ice adhesion was investigated under the extremely condensing condition. Different PDMS coatings on either smooth or roughened surfaces displayed a very similar impact to static and dynamic wettability under the ambient environment. However, the water impact behavior and ice adhesion under the extremely condensing condition between the hydrophobic and superhydrophobic surfaces are significantly different. One of the superhydrophobic surfaces (R2180) demonstrated an excellent water repelling capability to retard ice accumulation, and reduced ice adhesion strength even under the extremely condensing condition, and thus will be a good candidate for ice-phobic applications. This excellent ice-phobic property is attributed to the low surface free energy of the coating, which effectively prevents the water condensation inside the cavities of the hierarchical superhydrophobic structures and thus maintains "air cushion" on the solid/water interface, indicated by a very low solid-liquid contact area increase after surface is exposed to this condensing weather condition. This result demonstrates that the "air cushion" in a superhydrophobic surface could be maintained even under an extremely condensing condition by carefully selection of coating composition with a very low surface free energy.

  19. Frontonasal dysmorphology in bipolar disorder by 3D laser surface imaging and geometric morphometrics: comparisons with schizophrenia.

    LENUS (Irish Health Repository)

    Hennessy, Robin J

    2010-09-01

    Any developmental relationship between bipolar disorder and schizophrenia engenders continuing debate. As the brain and face emerge in embryological intimacy, brain dysmorphogenesis is accompanied by facial dysmorphogenesis. 3D laser surface imaging was used to capture the facial surface of 13 male and 14 female patients with bipolar disorder in comparison with 61 male and 75 female control subjects and with 37 male and 32 female patients with schizophrenia. Surface images were analysed using geometric morphometrics and 3D visualisations to identify domains of facial shape that distinguish bipolar patients from controls and bipolar patients from those with schizophrenia. Both male and female bipolar patients evidenced significant facial dysmorphology: common to male and female patients was overall facial widening, increased width of nose, narrowing of mouth and upward displacement of the chin; dysmorphology differed between male and female patients for nose length, lip thickness and tragion height. There were few morphological differences in comparison with schizophrenia patients. That dysmorphology of the frontonasal prominences and related facial regions in bipolar disorder is more similar to than different from that found in schizophrenia indicates some common dysmorphogenesis. Bipolar disorder and schizophrenia might reflect similar insult(s) acting over slightly differing time-frames or slightly differing insult(s) acting over a similar time-frame.

  20. Analysis of Green functions obtained by cross-correlations for MASE stations

    Science.gov (United States)

    Padilla, G. V. Vera

    2012-04-01

    We used continuous records of broadband seismic stations of the MASE experiment to obtain observed Green's functions using the method of ambient noise cross-correlations. The experiment consisted of 100 stations distributed along a perpendicular line to the Mesoamerican trench across the Valley of Mexico. The stations recorded continuously at 100 sps for more than two years. The geometry of the array provide a good opportunity to study the attenuation effects along the coast-perpendicular structure. The method we used to compute Green functions involves a strong data pre-processing (temporal normalization and spectral whitening). However, our results show that the amplitude of the cross-correlations still contains information about the surface waves attenuation and probably local amplification effects. Records from two regional earthquakes located close to Acapulco were used for comparison.

  1. Final EIS for the Proposed Homeporting of Additional Surface Ships at Naval Station, Mayport, FL. Volume 1. Final Environmental Impact Statement

    Science.gov (United States)

    2008-11-21

    and the native population’s transition from nomadic, big game subsistence/settlement patterns to a more sedentary lifestyle residing along the...Dental Clinic, Chapel, Child Development Center, and NAVSTA Mayport Family Housing. Final EIS for the Proposed Homeporting of Additional Surface Ships...for the more coastal lifestyle (Brockington & Associates 1998, Hardy Heck Moore Inc. 2001). The Late Archaic sub-period underwent another climate

  2. Comparison of the lateral retention forces on sessile and pendant water drops on a solid surface

    Science.gov (United States)

    de la Madrid, Rafael; Whitehead, Taylor; Irwin, George M.

    2015-06-01

    We present a simple experiment that demonstrates how a water drop hanging from a Plexiglas surface (pendant drop) experiences a lateral retention force that is comparable to, and in some cases larger than, the lateral retention force on a drop resting on top of the surface (sessile drop). The experiment also affords a simple demonstration of the Coriolis effect in two dimensions.

  3. Comparison of the lateral retention forces on sessile and pendant water drops on a solid surface

    OpenAIRE

    de la Madrid, Rafael; Whitehead, Taylor; Irwin, George

    2015-01-01

    We present a simple experiment that demonstrates how a water drop hanging from a Plexiglas surface (pendant drop) experiences a lateral retention force that is comparable to, and in some cases larger than, the lateral retention force on a drop resting on top of the surface (sessile drop). The experiment also affords a simple demonstration of the Coriolis effect in two dimensions.

  4. On the Surface Free Energy of PVC/EVA Polymer Blends: Comparison of Different Calculation Methods.

    Science.gov (United States)

    Michalski; Hardy; Saramago

    1998-12-01

    The surface free energy of polymeric films of polyvinylchloride (PVC) + poly(ethylene-co-vinylacetate) (EVA) blends was calculated using the van Oss treatment (Lifshitz and electron donor-electron acceptor components of surface free energy) and the Owens-Wendt treatment (dispersive and nondispersive components of surface free energy). Surface free energy results were found to be greatly dependent on the calculation method and on the number of standard liquids used for contact angle measurements. The nondispersive/donor-acceptor surface free energy component and the total surface free energy of polymeric films were always higher when the van Oss treatment was used compared to the Owens-Wendt treatment. Conversely, both methods led to similar apolar/Lifshitz components. All the calculation methods were in good agreement for the surface free energy of PVC; however, a discrepancy between the methods arose as EVA content in the blends increased. It seems that there is not yet a definite solution for the calculation of solid surface free energy. Further developments of existing models are needed in order to gain consistency when calculating this important physicochemical quantity. Copyright 1998 Academic Press.

  5. Comparison of sessile drop and captive bubble methods on rough homogeneous surfaces: a numerical study.

    Science.gov (United States)

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Marmur, A; Cabrerizo-Vílchez, M A

    2011-08-02

    Quasi-static experiments using sessile drops and captive bubbles are the most employed methods for measuring advancing and receding contact angles on real surfaces. These observable contact angles are the most easily accessible and reproducible. However, some properties of practical surfaces induce certain phenomena that cause a built-in uncertainty in the estimation of advancing and receding contact angles. These phenomena are well known in surface thermodynamics as stick-slip phenomena. Following the work of Marmur (Marmur, A. Colloids Surf., A 1998, 136, 209-215), where the stick-slip effects were studied with regard to sessile drops and captive bubbles on heterogeneous surfaces, we developed a novel extension of this study by adding the effects of roughness to both methods for contact angle measurement. We found that the symmetry between the surface roughness problem and the chemical heterogeneity problem breaks down for drops and bubbles subjected to stick-slip effects.

  6. Comparison of satellite and airborne sensor data on sea surface temperature and suspended solid distribution

    Science.gov (United States)

    Nishimura, Y.; Saito, K.; Hayakawa, S.; Narigasawa, K.

    1992-07-01

    Sea surface temperature and suspended solid were observed simultaneously by LANDSAT TM, NOAA AVHRR and airborne MSS. The authors compared the following items through the data, i.e., 1) Sea surface temperature, 2) Suspended solid in the sea water, 3) Monitoring ability on ocean environment. It was found that distribution patterns of sea surface temperature and suspended solid in the Ariake Sea obtained from LANDSAT TM are similar with those from airborne MSS in a scale of 1:300,000. Sea surface temperature estimated from NOAA AVHRR data indicates a fact of an ocean environment of the Ariake Sea and the around sea area. It is concluded that the TM data can be used for the monitoring of sea environment. The NOAA AVHRR data is useful for the estimation of sea surface temperature with the airborne MSS data.

  7. Comparison of Simulated and Measured Fluid-Surface Oscillation Frequencies in a Channel

    Science.gov (United States)

    Trapuzzano, Matthew; Pierre, Kiesha; Tufekcioglu, Emre; Guldiken, Rasim; Tejada-Martinez, Andres; Crane, Nathan

    2016-11-01

    Many important processes from agriculture to manufacturing depend on the wetting of fluids on rough or textured surfaces. This has traditionally been studied from a macro-perspective. The effects of these surface features can be dramatically altered by vibrations that overcome energy barriers to contact line motion caused by surface roughness. In order to study these effects in confined geometries and at different length scales, a validated model is required. This presentation will compare the measured and simulated frequencies of capillary vibrations in a cylindrical glass tube. Fluid surface vibrations are excited externally through deformation of the interface. The resulting surface oscillations are observed with a high speed video camera and the dominant oscillation frequencies are calculated. The measured oscillation frequencies are compared to predictions from transient CFD simulations across a range of interface diameters from 400 um to 1.5 mm. These results may be used to inform studies of wetting under vibration. NSF CMMI-1361919.

  8. Comparison of microfacet BRDF model to modified Beckmann-Kirchhoff BRDF model for rough and smooth surfaces.

    Science.gov (United States)

    Butler, Samuel D; Nauyoks, Stephen E; Marciniak, Michael A

    2015-11-02

    A popular class of BRDF models is the microfacet models, where geometric optics is assumed. In contrast, more complex physical optics models may more accurately predict the BRDF, but the calculation is more resource intensive. These seemingly disparate approaches are compared in detail for the rough and smooth surface approximations of the modified Beckmann-Kirchhoff BRDF model, assuming Gaussian surface statistics. An approximation relating standard Fresnel reflection with the semi-rough surface polarization term, Q, is presented for unpolarized light. For rough surfaces, the angular dependence of direction cosine space is shown to be identical to the angular dependence in the microfacet distribution function. For polished surfaces, the same comparison shows a breakdown in the microfacet models. Similarities and differences between microfacet BRDF models and the modified Beckmann-Kirchhoff model are identified. The rationale for the original Beckmann-Kirchhoff F(bk)(2) geometric term relative to both microfacet models and generalized Harvey-Shack model is presented. A modification to the geometric F(bk)(2) term in original Beckmann-Kirchhoff BRDF theory is proposed.

  9. Spectral analysis of atmospheric composition: application to surface ozone model-measurement comparisons

    Science.gov (United States)

    Bowdalo, Dene R.; Evans, Mathew J.; Sofen, Eric D.

    2016-07-01

    Models of atmospheric composition play an essential role in our scientific understanding of atmospheric processes and in providing policy strategies to deal with societally relevant problems such as climate change, air quality, and ecosystem degradation. The fidelity of these models needs to be assessed against observations to ensure that errors in model formulations are found and that model limitations are understood. A range of approaches are necessary for these comparisons. Here, we apply a spectral analysis methodology for this comparison. We use the Lomb-Scargle periodogram, a method similar to a Fourier transform, but better suited to deal with the gapped data sets typical of observational data. We apply this methodology to long-term hourly ozone observations and the equivalent model (GEOS-Chem) output. We show that the spectrally transformed observational data show a distinct power spectrum with regimes indicative of meteorological processes (weather, macroweather) and specific peaks observed at the daily and annual timescales together with corresponding harmonic peaks at one-half, one-third, etc., of these frequencies. Model output shows corresponding features. A comparison between the amplitude and phase of these peaks introduces a new comparison methodology between model and measurements. We focus on the amplitude and phase of diurnal and seasonal cycles and present observational/model comparisons and discuss model performance. We find large biases notably for the seasonal cycle in the mid-latitude Northern Hemisphere where the amplitudes are generally overestimated by up to 16 ppbv, and phases are too late on the order of 1-5 months. This spectral methodology can be applied to a range of model-measurement applications and is highly suitable for Multimodel Intercomparison Projects (MIPs).

  10. Comparison of Protocols for Walking and Running Kinematics Based on Skin Surface Markers and Rigid Clusters of Markers

    OpenAIRE

    Miana, AN; Prudencio, MV; Barros, RML

    2009-01-01

    The purpose of this study was to compare the two main types of marker sets for human body representation based on rigid clusters of markers and skin surface markers for measuring kinematics during walking and running. Velocity, body segment, and joint angle were considered in the comparison of both protocols. Six male athletes were Studied during treadmill gait at 1.4 and 5.5 m/s and recorded with 8 high speed video cameras. The subjects used simultaneously both protocols in the same walking ...

  11. Comparison of Observed Surface Temperatures of 4 Vesta to the KRC Thermal Model

    Science.gov (United States)

    Titus, T. N.; Becker, K. J.; Anderson, J. A.; Capria, M. T.; Tosi, F.; DeSanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.-P.; McCord, T. B.; Li, J.-Y.; Russell, C. T.; Ryamond, C. A.; Mittlefehldt, D.; Toplis, M.; Forni, O.; Sykes, M. V.

    2012-01-01

    In this work, we will compare ob-served temperatures of the surface of Vesta using data acquired by the Dawn [1] Visible and Infrared Map-ping Spectrometer (VIR-MS) [2] during the approach phase to model results from the KRC thermal model. High thermal inertia materials, such as bedrock, resist changes in temperature while temperatures of low thermal inertia material, such as dust, respond quickly to changes in solar insolation. The surface of Vesta is expected to have low to medium thermal inertia values, with the most commonly used value being extremely low at 15 TIU [4]. There are several parameters which affect observed temperatures in addition to thermal inertia: bond albedo, slope, and surface roughness. In addition to these parameters, real surfaces are rarely uniform monoliths that can be described by a single thermal inertia value. Real surfaces are often vertically layered or are mixtures of dust and rock. For Vesta's surface, with temperature extremes ranging from 50 K to 275 K and no atmosphere, even a uniform monolithic surface may have non-uniform thermal inertia due to temperature dependent thermal conductivity.

  12. Winds measured by the Rover Environmental Monitoring Station (REMS) during the Mars Science Laboratory (MSL) rover's Bagnold Dunes Campaign and comparison with numerical modeling using MarsWRF

    Science.gov (United States)

    Newman, Claire E.; Gómez-Elvira, Javier; Marin, Mercedes; Navarro, Sara; Torres, Josefina; Richardson, Mark I.; Battalio, J. Michael; Guzewich, Scott D.; Sullivan, Robert; de la Torre, Manuel; Vasavada, Ashwin R.; Bridges, Nathan T.

    2017-07-01

    A high density of REMS wind measurements were collected in three science investigations during MSL's Bagnold Dunes Campaign, which took place over ∼80 sols around southern winter solstice (Ls∼90°) and constituted the first in situ analysis of the environmental conditions, morphology, structure, and composition of an active dune field on Mars. The Wind Characterization Investigation was designed to fully characterize the near-surface wind field just outside the dunes and confirmed the primarily upslope/downslope flow expected from theory and modeling of the circulation on the slopes of Aeolis Mons in this season. The basic pattern of winds is 'upslope' (from the northwest, heading up Aeolis Mons) during the daytime (∼09:00-17:00 or 18:00) and 'downslope' (from the southeast, heading down Aeolis Mons) at night (∼20:00 to some time before 08:00). Between these times the wind rotates largely clockwise, giving generally westerly winds mid-morning and easterly winds in the early evening. The timings of these direction changes are relatively consistent from sol to sol; however, the wind direction and speed at any given time shows considerable intersol variability. This pattern and timing is similar to predictions from the MarsWRF numerical model, run at a resolution of ∼490 m in this region, although the model predicts the upslope winds to have a stronger component from the E than the W, misses a wind speed peak at ∼09:00, and under-predicts the strength of daytime wind speeds by ∼2-4 m/s. The Namib Dune Lee Investigation reveals 'blocking' of northerly winds by the dune, leaving primarily a westerly component to the daytime winds, and also shows a broadening of the 1 Hz wind speed distribution likely associated with lee turbulence. The Namib Dune Side Investigation measured primarily daytime winds at the side of the same dune, in support of aeolian change detection experiments designed to put limits on the saltation threshold, and also appears to show the

  13. Comparison of porcelain surface and flexural strength obtained by microwave and conventional oven glazing.

    Science.gov (United States)

    Prasad, Soni; Monaco, Edward A; Kim, Hyeongil; Davis, Elaine L; Brewer, Jane D

    2009-01-01

    Although the superior qualities of microwave technology are common knowledge in the industry, effects of microwave glazing of dental ceramics have not been investigated. The purpose of this study was to investigate the surface roughness and flexural strength achieved by glazing porcelain specimens in a conventional and microwave oven. Thirty specimens of each type of porcelain (Omega 900 and IPS d.Sign) were fabricated and sintered in a conventional oven. The specimens were further divided into 3 groups (n=10): hand polished (using diamond rotary ceramic polishers), microwave glazed, and conventional oven glazed. Each specimen was evaluated for surface roughness using a profilometer. The flexural strength of each specimen was measured using a universal testing machine. A 2-way ANOVA and Tukey HSD post hoc analysis were used to determine significant intergroup differences in surface roughness (alpha=.05). Flexural strength results were also analyzed using 2-way ANOVA, and the Weibull modulus was determined for each of the 6 groups. The surfaces of the specimens were subjectively evaluated for cracks and porosities using a scanning electron microscope (SEM). A significant difference in surface roughness was found among the surface treatments (P=.02). Follow-up tests showed a significant difference in surface roughness between oven-glazed and microwave-glazed treatments (P=.02). There was a significant difference in flexural strength between the 2 porcelains (Pmicrowave-glazed group was the highest (1.9) as compared to the other groups. The surface character of microwave-glazed porcelain was superior to oven-glazed porcelain. Omega 900 had an overall higher flexural strength than IPS d.Sign. Weibull distributions of flexural strengths for Omega 900 oven-glazed and microwave-glazed specimens were similar. SEM analysis demonstrated a greater number of surface voids and imperfections in IPS d. Sign as compared to Omega 900.

  14. Non-Coop Station History

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Station history documentation for stations outside the US Cooperative Observer network. Primarily National Weather Service stations assigned WBAN station IDs. Other...

  15. Procedural guide for the design of transit stations and terminals

    Energy Technology Data Exchange (ETDEWEB)

    Demetsky, M.J.; Hoel, L.A.; Virkler, M.R.

    1977-06-01

    State-of-the-art concepts regarding the planning, design, and evaluation of passenger transportation stations are discussed. The material directs transportation planning teams to search for efficient station designs. The important stages and considerations in a comprehensive terminal analysis methodology are described. The transit station design process requires contributions from many disciplines and skills. The report given will help coordinate station development programs in accommodating inputs from the disciplines, and it highlights the elements of different stations to assure valid comparisons relative to performance and cost criteria.

  16. Comparison of two different plasma surface-modification techniques for the covalent immobilization of protein monolayers.

    Science.gov (United States)

    Cifuentes, Anna; Borrós, Salvador

    2013-06-04

    The immobilization of biologically active species is crucial for the fabrication of smart bioactive surfaces. For this purpose, plasma polymerization is frequently used to modify the surface nature without affecting the bulk properties of the material. Thus, it is possible to create materials with surface functional groups that can promote the anchoring of all kinds of biomolecules. Different methodologies in protein immobilization have been developed in recent years, although some drawbacks are still not solved, such as the difficulties that some procedures involve and/or the denaturalization of the protein due to the immobilization process. In this work, two different strategies to covalently attach bovine serum albumin (BSA) protein are developed. Both techniques are compared in order to understand how the nature of the surface modification affects the conformation of the protein upon immobilization.

  17. [Determination of critical surface tension--a comparison of 2 methods].

    Science.gov (United States)

    Lippold, B C; Ohm, A

    1988-03-01

    Two methods for the determination of the critical surface tension (gamma c) of pharmaceutical powders are compared: the so called "sinking-technique", which works by measuring the complete sinking of powders in liquids of varying surface tension and the determination of the critical surface tension by measuring the contact angle in dependence on the surface tension of wetting solvent/water-mixtures by means of the sessile drop-technique. The simple sinking-technique gives gamma c-values which only show a moderate degree of agreement with those determined by the sessile drop-technique. Thus the values determined by the sinking-technique are usually 1-3 mN/m higher than those determined by the sessile drop-technique.

  18. A comparison of synthetic aperture radars applied for satellite remote sensing of the ocean surface

    Digital Repository Service at National Institute of Oceanography (India)

    Tilley, D.G.; Sarma, Y.V.B.

    surface winds. The environmental interpretation of these remotely sensed ocean data is often restrictEd. by incomplete understanding of SAR systems' capabilities and limitations. Hence, in this paper, the radiometric properties and spatial resolution...

  19. Comparison among four kinds of data of sea surface wind stress in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    谢强; 王卫强; 毛庆文

    2002-01-01

    By using remote sensing (ERS) data, FSU data, GOADS data and Hellerman & Rcsenstein objective analysis data to analyze the sea surface wind stress in the South China Sea, it is found that the remote sensing data have higher resolution and more reasonable values. Therefore we suggest that remote sensing data be chosen in the study of climatological features of sea surface wind stress and its seasonal variability in the South China Sea, especially in the study of small and middle scale eddies.

  20. Hydrophobic recovery of VUV/NH3 modified polyolefin surfaces: Comparison with plasma treatments in nitrogen

    Science.gov (United States)

    Truica-Marasescu, F.; Guimond, S.; Jedrzejowski, P.; Wertheimer, M. R.

    2005-07-01

    Film samples of two very pure polyolefins (low density polyethylene, LDPE and biaxially oriented polypropylene, BOPP) were surface-modified by two different methods, namely vacuum ultraviolet (VUV) irradiation with a Kr resonant lamp in low-pressure NH3 gas, and atmospheric pressure glow discharge (APGD) plasma treatment in pure N2 gas. Samples were then stored in air and the time-dependence of surface properties (the surface energy and chemical composition) was monitored using several complementary surface-sensitive techniques: contact angle goniometry (CAG), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). We show that the main mechanism responsible for hydrophobic recovery is the motion of polymer chains and chain segments, which governs an apparent "loss" of functional groups, within the first monolayers of the surface (∼1 nm). Finally, comparing BOPP samples modified by both techniques, we show that aging can be reduced by crosslinking near the surface, as illustrated by depth-sensing nano-indentation measurements.

  1. Surface dose measurements and comparison of unflattened and flattened photon beams

    Directory of Open Access Journals (Sweden)

    Ashokkumar Sigamani

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the central axis dose in the build-up region and the surface dose of a 6 MV and 10 MV flattened photon beam (FB and flattening filter free (FFF therapeutic photon beam for different square field sizes (FSs for a Varian Truebeam linear accelerator using parallel-plate ionization chamber and Gafchromic film. Knowledge of dosimetric characteristics in the build-up region and surface dose of the FFF is essential for clinical care. The dose measurements were also obtained empirically using two different commonly used dosimeters: a p-type photon semiconductor dosimeter and a cylindrical ionization chamber. Surface dose increased linearly with FS for both FB and FFF photon beams. The surface dose values of FFF were higher than the FB FSs. The measured surface dose clearly increases with increasing FS. The FFF beams have a modestly higher surface dose in the build-up region than the FB. The dependence of source to skin distance (SSD is less significant in FFF beams when compared to the flattened beams at extended SSDs.

  2. Comparison of pool boiling heat transfer for different tunnel-pore surfaces

    Science.gov (United States)

    Pastuszko, Robert

    2014-03-01

    Complex experimental investigations of boiling heat transfer on structured surfaces covered with perforated foil were performed. Experimental data were discussed for three kinds of enhanced surfaces: tunnel structures (TS), narrow tunnel structures (NTS) and mini-fins with the copper wire net (NTS-L). The experiments were carried out with water, ethanol, R-123 and FC-72 at atmospheric pressure. The TS and NTS surfaces were manufactured out of perforated copper foil (hole diameters: 0.3, 0.4, 0.5 mm) sintered with the mini-fins, formed on the vertical side of the 5 and 10 mm high rectangular main fins and horizontal inter-fin surface. The NTS-L surfaces were formed by mini-fins of 0.5 and 1 mm height uniformly spaced on the base surface. The wire mesh with an aperture of 0.32, 0.4 and 0.5 mm sintered with the fin tips formed a system of connected perpendicular horizontal tunnels. The tunnel width was 0.6 - 1.0 - 1.5 mm and the depth was 0.5 or 1.0 mm. The effects of the Bond number and dimensionless parameters for three kinds of enhanced structures on heat transfer ratio at nucleate pool boiling were examined.

  3. Comparison of pool boiling heat transfer for different tunnel-pore surfaces

    Directory of Open Access Journals (Sweden)

    Pastuszko Robert

    2014-03-01

    Full Text Available Complex experimental investigations of boiling heat transfer on structured surfaces covered with perforated foil were performed. Experimental data were discussed for three kinds of enhanced surfaces: tunnel structures (TS, narrow tunnel structures (NTS and mini-fins with the copper wire net (NTS-L. The experiments were carried out with water, ethanol, R-123 and FC-72 at atmospheric pressure. The TS and NTS surfaces were manufactured out of perforated copper foil (hole diameters: 0.3, 0.4, 0.5 mm sintered with the mini-fins, formed on the vertical side of the 5 and 10 mm high rectangular main fins and horizontal inter-fin surface. The NTS-L surfaces were formed by mini-fins of 0.5 and 1 mm height uniformly spaced on the base surface. The wire mesh with an aperture of 0.32, 0.4 and 0.5 mm sintered with the fin tips formed a system of connected perpendicular horizontal tunnels. The tunnel width was 0.6 – 1.0 – 1.5 mm and the depth was 0.5 or 1.0 mm. The effects of the Bond number and dimensionless parameters for three kinds of enhanced structures on heat transfer ratio at nucleate pool boiling were examined.

  4. Aeolian transport in the field: A comparison of the effects of different surface treatments

    Science.gov (United States)

    Dong, Zhibao; Lv, Ping; Zhang, Zhengcai; Qian, Guangqiang; Luo, Wanyin

    2012-05-01

    Aeolian transport represents the result of wind-surface interactions, and therefore depends strongly on variations in the characteristics of the sediment surface. We conducted field observations of aeolian transport of typical dune sand in three 80 m × 80 m plots with different surface treatments: gravel-covered sand, enclosed shifting sand, and open (unprotected) shifting sand. The study was performed at the Shapotou Aeolian Experiment Site in the southeastern part of China's Tengger Desert to compare the effects of these different surface treatments on aeolian transport. To do so, we analyzed the flux density profiles and transport rates above each surface. The flux density profiles for all three treatments followed the exponential decay law that was proposed by most previous researchers to describe the saltation flux density profiles. Coefficients of the exponential decay function were defined as a function of the surface and the wind velocity. The enclosed and open plots with shifting sand had similar flux density profiles, but the flux density above gravel-covered plots showed that transport decayed more slowly with increasing height, producing flux density profiles with a higher average saltation height. The transport rate above the three treatment plots tended to increase proportionally with the cube of the mean wind velocity and with the maximum wind velocity during the observation period, but was more strongly correlated with the square of drift potential. Transport rates above the plot with open shifting sand were greater than those above the plots with enclosed shifting sand and the gravel-covered plot.

  5. Space station, 1959 to . .

    Science.gov (United States)

    Butler, G. V.

    1981-04-01

    Early space station designs are considered, taking into account Herman Oberth's first space station, the London Daily Mail Study, the first major space station design developed during the moon mission, and the Manned Orbiting Laboratory Program of DOD. Attention is given to Skylab, new space station studies, the Shuttle and Spacelab, communication satellites, solar power satellites, a 30 meter diameter radiometer for geological measurements and agricultural assessments, the mining of the moons, and questions of international cooperation. It is thought to be very probable that there will be very large space stations at some time in the future. However, for the more immediate future a step-by-step development that will start with Spacelab stations of 3-4 men is envisaged.

  6. Occurrence of sulphate reducing bacteria (SRB associated with biocorrosion on metallic surfaces in a hydroelectric power station in Ibirama (SC - Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Dantas Marangoni

    2013-10-01

    Full Text Available The aim of this study was evaluate, two methods for the detection and identification of sulphate reducing bacteria (SRB: ML medium and PCR with specific primers for SRB groups. SRB were detected through the selective medium only on carbon steel, which showed corrosion. Employing specific PCR primer, SBR were detected from all the metallic components assayed, even those that did not present visible corrosion spots, such stainless steel and copper alloys. Despite the presence or absence of corrosion at the later stages effectively by using the selective medium,, the initial stages of the corrosion could only be detected by the amplification of total DNA with SRB specific primers. The early detection of SRB could be employed for preventing the damages on metal surfaces before the installation of corrosion processes. Strategies for reducing the time spent on SRB isolation and identification could be auxiliary tools for controlling the corrosion of materials.

  7. Comparison of Satellite-Derived and In-Situ Observations of Ice and Snow Surface Temperatures over Greenland

    Science.gov (United States)

    Hall, Dorothy K.; Box, Jason E.; Casey, Kimberly A.; Hook, Simon J.; Shuman, Christopher A.; Steffen, Konrad

    2008-01-01

    The most practical way to get a spatially broad and continuous measurements of the surface temperature in the data-sparse cryosphere is by satellite remote sensing. The uncertainties in satellite-derived LSTs must be understood to develop internally-consistent decade-scale land-surface temperature (LST) records needed for climate studies. In this work we assess satellite-derived "clear-sky" LST products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and LSTs derived from the Enhanced Thematic Mapper Plus (ETM+) over snow and ice on Greenland. When possible, we compare satellite-derived LSTs with in-situ air-temperature observations from Greenland Climate Network (GC-Net) automatic-weather stations (AWS). We find that MODIS, ASTER and ETM+ provide reliable and consistent LSTs under clear-sky conditions and relatively-flat terrain over snow and ice targets over a range of temperatures from -40 to 0 C. The satellite-derived LSTs agree within a relative RMS uncertainty of approx.0.5 C. The good agreement among the LSTs derived from the various satellite instruments is especially notable since different spectral channels and different retrieval algorithms are used to calculate LST from the raw satellite data. The AWS record in-situ data at a "point" while the satellite instruments record data over an area varying in size from: 57 X 57 m (ETM+), 90 X 90 m (ASTER), or to 1 X 1 km (MODIS). Surface topography and other factors contribute to variability of LST within a pixel, thus the AWS measurements may not be representative of the LST of the pixel. Without more information on the local spatial patterns of LST, the AWS LST cannot be considered valid ground truth for the satellite measurements, with RMS uncertainty approx.2 C. Despite the relatively large AWS-derived uncertainty, we find LST data are characterized by high accuracy but have uncertain absolute precision.

  8. Inter-Comparison of SMOS and Aquarius Sea Surface Salinity: Effects of the Dielectric Constant and Vicarious Calibration

    Science.gov (United States)

    Dinnat, Emmanuel P.; Boutin, Jacqueline; Yin, Xiaobin; Le Vine, David M.

    2014-01-01

    Two spaceborne instruments share the scientific objective of mapping the global Sea Surface Salinity (SSS). ESA's Soil Moisture and Ocean Salinity (SMOS) and NASA's Aquarius use L-band (1.4 GHz) radiometry to retrieve SSS. We find that SSS retrieved by SMOS is generally lower than SSS retrieved by Aquarius, except for very cold waters where SMOS SSS is higher overall. The spatial distribution of the differences in SSS is similar to the distribution of sea surface temperature. There are several differences in the retrieval algorithm that could explain the observed SSS differences. We assess the impact of the dielectric constant model and the ancillary sea surface salinity used by both missions for calibrating the radiometers and retrieving SSS. The differences in dielectric constant model produce differences in SSS of the order of 0.3 psu and exhibit a dependence on latitude and temperature. We use comparisons with the Argo in situ data to assess the performances of the model in various regions of the globe. Finally, the differences in the ancillary sea surface salinity products used to perform the vicarious calibration of both instruments are relatively small (0.1 psu), but not negligible considering the requirements for spaceborne remote sensing of SSS.

  9. Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

    Science.gov (United States)

    Moraczewski, Krzysztof; Rytlewski, Piotr; Malinowski, Rafał; Żenkiewicz, Marian

    2015-08-01

    The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm2 was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

  10. Identification and comparison of electrical tapes using instrumental and statistical techniques: I. Microscopic surface texture and elemental composition.

    Science.gov (United States)

    Goodpaster, John V; Sturdevant, Amanda B; Andrews, Kristen L; Brun-Conti, Leanora

    2007-05-01

    Comparisons of polyvinyl chloride electrical tape typically rely upon evaluating class characteristics such as physical dimensions, surface texture, and chemical composition. Given the various techniques that are available for this purpose, a comprehensive study has been undertaken to establish an optimal analytical scheme for electrical tape comparisons. Of equal importance is the development of a quantitative means for sample discrimination. In this study, 67 rolls of black electrical tape representing 34 different nominal brands were analyzed via scanning electron microscopy and energy dispersive spectroscopy. Differences in surface roughness, calendering marks, and filler particle size were readily apparent, including between some rolls of the same nominal brand. The relative amounts of magnesium, aluminum, silicon, sulfur, lead, chlorine, antimony, calcium, titanium, and zinc varied greatly between brands and, in some cases, could be linked to the year of manufacture. For the first time, quantitative differentiation of electrical tapes was achieved through multivariate statistical techniques, with 36 classes identified within the sample population. A single-blind study was also completed where questioned tape samples were correctly associated with known exemplars. Finally, two case studies are presented where tape recovered from an improvised explosive device is compared with tape recovered from a suspect.

  11. Comparison of surface fluxes and boundary-layer measurements at Arctic terrestrial sites

    Science.gov (United States)

    Grachev, Andrey; Uttal, Taneil; Persson, Ola; Stone, Robert; Crepinsek, Sara; Albee, Robert; Makshtas, Alexander; Kustov, Vasily; Repina, Irina; Artamonov, Arseniy

    2014-05-01

    Observational evidence suggests that atmospheric energy fluxes are a major contributor to the decrease of the Arctic pack ice, seasonal land snow cover and the warming of the surrounding land areas and permafrost layers. To better understand the atmosphere-surface exchange mechanisms, improve models, and to diagnose climate variability in the Arctic, accurate measurements are required of all components of the net surface energy budget and the carbon dioxide cycle over representative areas and over multiple years. This study analyzes and discusses variability of surface fluxes and basic meteorological parameters based on measurements made at several long-term research observatories near the coast of the Arctic Ocean located in USA (Barrow), Canada (Eureka), and Russia (Tiksi). Tower-based eddy covariance and solar radiation measurements provide a long-term near continuous temporal record of hourly average mass and energy fluxes respectively. The turbulent fluxes of the momentum, sensible heat, water vapor, and carbon dioxide are supported by additional atmospheric and surface/snow/permafrost measurements (mean wind speed, air temperature and humidity, upwelling and downwelling short-wave and long-wave atmospheric and surface radiation, snow depth, surface albedo, soil heat flux, active layer temperature profiles etc.) In this study we compare annual cycles of surface fluxes including solar radiation and other ancillary data to describe four seasons in the Arctic including spring onset of melt and fall onset of snow accumulation. Particular interest is a transition through freezing point, i.e. during transition from winter to spring and from summer to fall, when the carbon dioxide and/or water vapor turbulent fluxes change their direction. According to our data, in a summer period observed temporal variability of the carbon dioxide flux was generally in anti-phase with water vapor flux (downward CO2 flux and upward H2O flux). On average the turbulent flux of carbon

  12. Cooperative Station History Forms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Various forms, photographs and correspondence documenting the history of Cooperative station instrumentation, location changes, inspections, and...

  13. Amtrak Rail Stations (National)

    Data.gov (United States)

    Department of Transportation — Updated database of the Federal Railroad Administration's (FRA) Amtrak Station database. This database is a geographic data set containing Amtrak intercity railroad...

  14. Surface toughness of silicon nitride bioceramics: II, Comparison with commercial oxide materials.

    Science.gov (United States)

    McEntire, Bryan J; Enomoto, Yuto; Zhu, Wenliang; Boffelli, Marco; Marin, Elia; Pezzotti, Giuseppe

    2016-02-01

    Raman microprobe-assisted indentation, a micromechanics method validated in a companion paper, was used to compare the surface toughening behaviors of silicon nitride (Si3N4) and alumina-based bioceramics employed in joint arthroplasty (i.e., monolithic alumina, Al2O3, and yttria-stabilized zirconia (ZrO2)-toughened alumina, ZTA). Quantitative assessments of microscopic stress fields both ahead and behind the tip of Vickers indentation cracks propagated under increasing indentation loads were systematically made using a Raman microprobe with spatial resolution on the order of a single micrometer. Concurrently, crack opening displacement (COD) profiles were monitored on the same microcracks screened by Raman spectroscopy. The Raman eye clearly visualized different mechanisms operative in toughening Si3N4 and ZTA bioceramics (i.e., crack-face bridging and ZrO2 polymorphic transformation, respectively) as compared to the brittle behavior of monolithic Al2O3. Moreover, emphasis was placed on assessing not only the effectiveness but also the durability of such toughening effects when the biomaterials were aged in a hydrothermal environment. A significant degree of embrittlement at the biomaterial surface was recorded in the transformation-toughened ZTA, with the surface toughness reduced by exposure to the hydrothermal environment. Conversely, the Si3N4 biomaterial experienced a surface toughness value independent of hydrothermal attack. Crack-face bridging thus appears to be a durable surface toughening mechanism for biomaterials in joint arthroplasty.

  15. Internal photoemission from plasmonic nanoparticles: comparison between surface and volume photoelectric effects

    DEFF Research Database (Denmark)

    Uskov, Alexander; Protsenko, Igor E.; Ikhsanov, Renat S.;

    2014-01-01

    We study the emission of photoelectrons from plasmonic nanoparticles into a surrounding matrix. We consider two mechanisms of electron emission from the nanoparticles - surface and volume ones and use models for these two mechanisms which allow us to obtain analytical results for the photoelectro...... to take both mechanisms into account in the development of devices based on the photoelectric effect and when considering hot electron emission from a plasmonic nanoantenna....... emission rate from a nanoparticle. Calculations have been carried out for a step potential at the surface of a spherical nanoparticle, and a simple model for the hot electron cooling has been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary....... In accordance with our calculations, this possible predominance of the surface effect is based on two factors: (i) effective cooling of hot carriers during their propagation from the volume of the nanoparticle to its surface in the scenario of the volume mechanism and (ii) strengthening of the surface mechanism...

  16. Surface hardness comparison of resins polymerized by argon, xenon, and conventional light sources

    Science.gov (United States)

    Blankenau, Richard J.; Pace, Scott; Powell, G. L.; Wilwerding, Terry

    1996-04-01

    A great deal of discussion has taken place regarding how to properly polymerize light activated resins. Claims are made that effective testing can be made by using surface hardness tests on samples with various dental instruments. Although these tests would probably identify a material that had been very poorly polymerized it would not identify materials that were properly polymerized. The lack of consistent, reproducible forces and evaluation of the results make these test practically worthless. Surface hardness which is important clinically has value when combined with evaluation of the surface immediately adjacent to the light source and the surface adjacent to the tooth. Also immediate and 24 hour testing to allow for continued polymerization is helpful in determining how to achieve best results for our patients. A variety of new light sources have been introduced to dentistry with claims of faster and better polymerizations. The visible light units are also undergoing improvements to include built in meters to monitor light output. The purpose of this study was to evaluate the top and bottom surface hardness of a composite resin using the following light sources: argon, xenon, and two visible light sources.

  17. Comparison of glow argon plasma-induced surface changes of thermoplastic polymers

    Science.gov (United States)

    Řezníčková, A.; Kolská, Z.; Hnatowicz, V.; Stopka, P.; Švorčík, V.

    2011-01-01

    Modification of high-density polyethylene (PE), polytetrafluoroethylene (PTFE), polystyrene (PS), polyethyleneterephthalate (PET) and polypropylene (PP) by Ar plasma was studied. The amount of the ablated material was determined by gravimetry. Wettability of polymers after the plasma treatment was determined from the contact angle measurement. The changes in the surface morphology of polymers were observed using atomic force microscopy (AFM). Chemical structure of modified polymers was characterized by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Surface changes were also studied by the determination of electrokinetic potential ( ζ-potential). It was found that under the plasma treatment the polymers are ablated and their surface morphology and roughness are changed dramatically. XPS measurements indicate an oxidation of the polymer surface. The plasma treatment results in a dramatic increase of the ζ-potential. EPR data show different radical amount present on the treated surface of all polymers. Most significant changes due to the degradation of polymer chains are observed on PTFE.

  18. Comparison of different polishing methods on the surface roughness of microhybrid, microfill, and nanofill composite resins.

    Science.gov (United States)

    Moda, Mariana D; Godas, André Gustavo de L; Fernandes, Juliana C; Suzuki, Thaís Y U; Guedes, Ana Paula A; Briso, André L F; Bedran-Russo, Ana Karina; Dos Santos, Paulo H

    2017-08-01

    The aim of the present study was to evaluate the effect of different polishing methods on the surface roughness of resin-based composites subjected to a thermocycling procedure. A total of 192 specimens were divided into 24 groups, according to composite materials (Filtek Z250, Point 4, Renamel Nanofill, Filtek Supreme Plus, Renamel Microfill, and Premise) and finishing and polishing systems (Sof-Lex Pop On, Super Snap, Flexidisc, and Flexidisc+Enamelize). The specimens were subjected to thermocycling (5000 cycles). Filtek Supreme Plus showed the lowest surface roughness values before thermocycling. After thermocycling, Filtek Supreme Plus continued to have the lowest surface roughness, with a statistically-significant difference for the other materials. After thermocycling, there was no statistically-significant difference among all the polishing techniques studied. The thermocycling was concluded as being able to change composite resins' surface roughness, whereas different finishing and polishing methods did not result in surface roughness changes after thermocycling. © 2017 John Wiley & Sons Australia, Ltd.

  19. Comparison of remote sensing measurements with a two-scale polarimetric emission and scattering model for sea surfaces

    Science.gov (United States)

    Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Li, F. K.

    1993-01-01

    Recently, it has been observed that the brightness temperatures of sea surfaces correlate with the azimuth angle of the ocean wind vector, indicating that ocean wind direction can not only be retrieved from the microwave backscatter, but also from the brightness temperature measurements. In this paper, comparison of the theoretical result calculated from a two-scale emission and scattering model with the Seasat and SSM/I model functions and aircraft measurements is presented and potential applications of microwave polarimetry are discussed. In our two-scale model, the modified reflectivities of large scale surfaces are calculated by extending the small perturbation method to the second order for small scale perturbation with anisotropic directional spectrum. It was found that the modified reflectivities derived from the second-order scattered field agree excellently well with the results obtained from a Monte Carlo simulation technique which numerically calculates the polarimetric reflectivities of one-dimensional random rough surfaces with a power-law spectrum. Without the second-order correction, the modified reflectivities of the rough surfaces are significantly over-estimated and sign errors are observed in the third and fourth Stokes parameters for thermal emissions. The surface spectrum parameters and two-scale cutoff are selected so that the calculated scattering and emission signatures agree with the reported model functions for Seasat and SSM/I. Subsequently, the polarimetric signatures of sea surfaces are illustrated to indicate the possibility of reducing the number of azimuthal looks required for spaceborne sensors in the remote sensing of ocean wind by using the polarimetric information. Furthermore, it is found that contrary to the dependence of backscattering coefficients on incidence angles, polarimetric brightness temperatures display a stronger wind direction dependence in the near nadir-looking direction than away from nadir. Finally, we discuss

  20. VUV-induced nitriding of polymer surfaces: Comparison with plasma treatments in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Truica-Marasescu, F.; Guimond, S.; Wertheimer, M.R

    2003-08-01

    Film samples of two very pure polyolefins (low density polyethylene and biaxially oriented polypropylene) have been surface-modified by two different methods, vacuum ultraviolet (VUV) photochemistry in low pressure ammonia, and atmospheric pressure glow discharge plasma treatment in N{sub 2} gas. The results of these two treatments are compared, namely surface compositions (determined by X-ray photoelectron spectroscopy and infrared spectroscopy, ATR-FTIR) and surface energies (determined by contact angle goniometry with several probe liquids). We show that higher concentrations, [N], can be achieved by VUV photochemistry (up to 25%), that N is predominantly bonded as amine or amide groups, and that there exist certain particularities specific to each of the treatment methods investigated.

  1. VUV-induced nitriding of polymer surfaces: Comparison with plasma treatments in nitrogen

    Science.gov (United States)

    Truica-Marasescu, F.; Guimond, S.; Wertheimer, M. R.

    2003-08-01

    Film samples of two very pure polyolefins (low density polyethylene and biaxially oriented polypropylene) have been surface-modified by two different methods, vacuum ultraviolet (VUV) photochemistry in low pressure ammonia, and atmospheric pressure glow discharge plasma treatment in N 2 gas. The results of these two treatments are compared, namely surface compositions (determined by X-ray photoelectron spectroscopy and infrared spectroscopy, ATR-FTIR) and surface energies (determined by contact angle goniometry with several probe liquids). We show that higher concentrations, [N], can be achieved by VUV photochemistry (up to 25%), that N is predominantly bonded as amine or amide groups, and that there exist certain particularities specific to each of the treatment methods investigated.

  2. A comparison of en face and tangential wide-area excimer surface ablation in the rabbit.

    Science.gov (United States)

    Holme, R J; Fouraker, B D; Schanzlin, D J

    1990-06-01

    We used an argon fluoride excimer laser (193 nm) to perform anterior corneal surface ablation in New Zealand white rabbits (25 eyes) using both en face and tangential methods. We followed up the animals for 90 days using slit-lamp photography and pachymetry at predetermined intervals. We also examined selected tissues with scanning electron microscopy and transmission electron microscopy. Immediate and subsequent examinations revealed significant differences in clarity between the two groups. When viewed through slit-lamp microscopy, the rabbits undergoing the en face method exhibited hazy corneas and irregular surfaces, whereas the corneas that underwent tangential keratectomy demonstrated less haze and fewer surface irregularities. Through histologic study and electron microscopy, we corroborated this finding. At 30 days, there was a statistically significant difference in clarity between en face--treated corneas and those treated tangentially.

  3. Comparison of adhesion of the food spoilage bacterium Shewanella putrefaciens to stainless steel and silver surfaces

    DEFF Research Database (Denmark)

    Hjelm, Mette; Hilbert, Lisbeth Rischel; Møller, Per;

    2002-01-01

    (new silver, tarnished silver and sulphide treated silver) was compared to adhesion to stainless steel (AISI 316). Numbers of attached bacteria (cfu cm-2) were estimated using the Malthus indirect conductance method. A lower number of attached bacteria were measured on new silver surfaces compared...... to stainless steel for samples taken after 24 hours. However this was not significant (P > 0.05). The numbers of attached bacteria were consistently lower when tarnished silver surfaces were compared to stainless steel and some, but not all, experiments showed statistically significant. A difference of more...... than one log unit in bacterial numbers on the two types of materials was observed, but for most samples the difference was within one log unit. Treating new silver with sulphide to try to reproduce a tarnished silver surface did not result in a similar lowering of adhering cells when compared to steel...

  4. Comparison of bacterial cells and amine-functionalized abiotic surfaces as support for Pd nanoparticle synthesis

    DEFF Research Database (Denmark)

    De Corte, Simon; Bechstein, Stefanie; Lokanathan, Arcot R.

    2013-01-01

    An increasing demand for catalytic Pd nanoparticles has motivated the search for sustainable production methods. An innovative approach uses bacterial cells as support material for synthesizing Pd nanoparticles by reduction of Pd(II) with e.g. hydrogen or formate. Nevertheless, drawbacks...... nanoparticles, and that abiotic surfaces could support the Pd particle synthesis as efficiently as bacteria. In this study, we explore the possibility of replacing bacteria with amine-functionalized materials, and we compare different functionalization strategies. Pd nanoparticles formed on the support...... of microbially supported Pd catalysts are the low catalytic activity compared to conventional Pd nanocatalysts and the possible poisoning of the catalyst surface by sulfur originating from bacterial proteins. A recent study showed that amine groups were a key component in surface-supported synthesis of Pd...

  5. Hydrogen sulphide removal from corroding concrete: comparison between surface removal rates and biomass activity.

    Science.gov (United States)

    Jensen, H S; Nielsen, A H; Lens, P N L; Hvitved-Jacobsen, T; Vollertsen, J

    2009-11-01

    Corrosion of concrete sewer pipes caused by hydrogen sulphide is a problem in many sewer networks. The mechanisms of production and fate of hydrogen sulphide in the sewer biofilms and wastewater as well as its release to the sewer atmosphere are largely understood. In contrast, the mechanisms of the uptake of hydrogen sulphide on the concrete surfaces and subsequent concrete corrosion are basically unknown. To shed light on these mechanisms, the uptake of hydrogen sulphide from a sewer gas phase was compared to the biological hydrogen sulphide removal potential of the concrete corrosion products. The results showed that both microbial degradation at and sorption to the concrete surfaces were important for the uptake of hydrogen sulphide on the concrete surfaces.

  6. Polycyclic aromatic hydrocarbons in urban street dust and surface soil: comparisons of concentration, profile, and source.

    Science.gov (United States)

    Wang, De-Gao; Yang, Meng; Jia, Hong-Liang; Zhou, Lei; Li, Yi-Fan

    2009-02-01

    Street dust and surface soil samples in urban areas of Dalian, a coastal city in Liaoning Province, China, were collected and analyzed for 25 polycyclic aromatic hydrocarbons (PAHs). The concentrations, distribution, and sources of PAHs in dust and soil were determined. The concentrations of total PAHs in street dust ranged between 1890 and 17,070 ng/g (dry weight), with an average of 7460 ng/g, whereas the concentrations of total PAHs in surface soil varied greatly, from 650 to 28,900 ng/g, with a mean value of 6440 ng/g. Statistical paired t-test confirmed that total PAH concentrations have no significant difference between street dust and surface soil. Mean PAH concentrations in two type samples were much higher at industrial sites than at business/residential or garden sites. PAHs were dominated by higher molecular weight PAH (4- to 6-ring) homologues, which accounted for about 73% and 72% of total PAHs in street dust and surface soil, respectively. Principal component analysis was used in source apportionment of PAHs in dust and soil. Pyrogenic and petrogenic sources contributed 70% and 22.4% of total PAHs in street dusts, and fossil fuel (coal and petroleum) and biomass combustion accounted for 64.4% and 5.6% of total PAHs in pyrogenic sources, respectively. In surface soil, total PAHs were dominated by pyrogenic sources. The diagnostic ratios of benz[a]anthracene/chrysene confirmed that PAHs in street dust and surface soil of a Dalian urban zone might come mostly from the emission of local sources.

  7. Comparison of hospital room surface disinfection using a novel ultraviolet germicidal irradiation (UVGI) generator.

    Science.gov (United States)

    Jelden, Katelyn C; Gibbs, Shawn G; Smith, Philip W; Hewlett, Angela L; Iwen, Peter C; Schmid, Kendra K; Lowe, John J

    2016-09-01

    The estimated 721,800 hospital acquired infections per year in the United States have necessitated development of novel environmental decontamination technologies such as ultraviolet germicidal irradiation (UVGI). This study evaluated the efficacy of a novel, portable UVGI generator (the TORCH, ChlorDiSys Solutions, Inc., Lebanon, NJ) to disinfect surface coupons composed of plastic from a bedrail, stainless steel, chrome-plated light switch cover, and a porcelain tile that were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus faecalis (VRE). Each surface type was placed at 6 different sites within a hospital room and treated by 10-min ultraviolet-C (UVC) exposures using the TORCH with doses ranging from 0-688 mJ/cm(2) between sites. Organism reductions were compared with untreated surface coupons as controls. Overall, UVGI significantly reduced MRSA by an average of 4.6 log10 (GSD: 1.7 log10, 77% inactivation, p < 0.0001) and VRE by an average of 3.9 log10 (GSD: 1.7 log10, 65% inactivation, p < 0.0001). MRSA on bedrail was reduced significantly (p < 0.0001) less than on other surfaces, while VRE was reduced significantly less on chrome (p = 0.0004) and stainless steel (p = 0.0012) than porcelain tile. Organisms out of direct line of sight of the UVC generator were reduced significantly less (p < 0.0001) than those directly in line of sight. UVGI was found an effective method to inactivate nosocomial pathogens on surfaces evaluated within the hospital environment in direct line of sight of UVGI treatment with variation between organism and surface types.

  8. Comparison and optimization of randomly textured surfaces in thin-film solar cells.

    Science.gov (United States)

    Rockstuhl, C; Fahr, S; Bittkau, K; Beckers, T; Carius, R; Haug, F-J; Söderström, T; Ballif, C; Lederer, F

    2010-09-13

    Using rigorous diffraction theory we investigate the scattering properties of various random textures currently used for photon management in thin-film solar cells. We relate the haze and the angularly resolved scattering function of these cells to the enhancement of light absorption. A simple criterion is derived that provides an explanation why certain textures operate more beneficially than others. Using this criterion we propose a generic surface profile that outperforms the available substrates. This work facilitates the understanding of the effect of randomly textured surfaces and provides guidelines towards their optimization.

  9. Quality Evaluations and Comparisons of Radiation Data at Lin'an and Longfengshan Stations%临安与龙凤山辐射数据质量及初步结果比较

    Institute of Scientific and Technical Information of China (English)

    宋建洋; 郑向东; 程兴宏; 马千里; 俞向明; 代鑫; 于大江

    2013-01-01

    采用国际通用的辐射数据质量评估方法对2005-2011年浙江临安、黑龙江龙凤山两个区域大气本底站辐射观测资料进行质量评估与比较分析.结果表明:两站辐射数据通过物理可能限制检验与极端罕见限制检验的百分比均超过99.5%,但通过相关要素比较限制检验的百分比上,临安与龙凤山站分别降至97.9%与95.9%;双轴定位追踪太阳出现偏差是造成直接辐射与散射辐射数据精度降低的主要原因.CM21表的热偏移在-5 W·m-2以内,而其进行热偏移订正可以显著提高数据的通过率.对应同一太阳天顶角,临安站晴空总辐射与直接辐射均低于龙凤山站,散射辐射则相反,其原因是临安的大气透明系数较低,大气浑浊度较高.2006-2011年,临安站的大气向下长波辐射呈下降趋势,达到了0.01的显著性水平,且其多年平均值(363.7±59.3 W·m-2)显著高于龙凤山站(274.9±77.6 W· m-2);龙凤山站晴空太阳总辐射呈增加趋势,达到了0.1的显著性水平.%Solar radiation is widely used in the studies of climate change,evaluation of model simulations and assessment of solar radiation energy resources. Therefore, accurate observations of solar radiation data are absolutely needed. An international BSRN method of solar data quality assessment and quality control (QA-QC) is applied to investigate data quality of solar radiation and downward long-wave radiation (DLR) measured from 2005 to 2011 at Lin'an and Longfengshan, two regional background stations in the mainland of China. The method includes 3 steps of testing. They are the sequential limits of physically possible, extremely rare and relevant factor comparison. The results show that percentages of radiation data meeting requirements of the first two test steps of the quality test at both sites are more than 99. 5% , but in the third step, the percentage dropped to 97. 9% at Lin'an and 95. 9% at Longfengshan. The error of the

  10. Comparison of temperature effects on E. coli, Salmonella, and Enterococcus survival in surface waters

    Science.gov (United States)

    The objective of this study was to compare the dependencies of survival rates on temperature for indicator organisms E. coli and Enterococcus and the pathogen Salmonella in surface waters. A database consisting of 86 survival datasets from peer-reviewed papers on inactivation of E. coli, Salmonella...

  11. Comparison of systems for high speed surface flaw measurements of cartridges

    Energy Technology Data Exchange (ETDEWEB)

    Swinth, K. L.; Kirihara, L. J.; Coleman, W. J.

    1979-01-01

    Instrumentation to detect surface flaws in cartridge cases has been developed for high speed on-line inspection. Scattering of light from a line focused on the case surface indicates the presence of surface flaws and the instrumentation permits rough categorization of flaws into dents and scratches. Two methods of light detection have been implemented, and the purpose of this paper is to compare these techniques. The first technique uses fiber optics to collect the scattered light and carry it to a photomultiplier tube to generate a signal, which the second technique uses solid-state diodes to produce the signal. Angled surfaces such as the shoulder on the cartridge case influence the response of the fiber-optics due to the acceptance cone of the fibers. To circumvent this problem, the fibers must be judiciously positioned during manufacture of the fiber-optic bundles. The solid-state diodes do not have the limited acceptance angle and thus provide more uniform response. However, the diodes require placement of electronics on the rotating exam wheel near the detectors. The processing electronics for both systems are identical.

  12. A comparison of two open source LiDAR surface classification algorithms

    Science.gov (United States)

    With the progression of LiDAR (Light Detection and Ranging) towards a mainstream resource management tool, it has become necessary to understand how best to process and analyze the data. While most ground surface identification algorithms remain proprietary and have high purchase costs; a few are op...

  13. Critique of Sikkink and Keane's comparison of surface fuel sampling techniques

    Science.gov (United States)

    Clinton S. Wright; Roger D. Ottmar; Robert E. Vihnanek

    2010-01-01

    The 2008 paper of Sikkink and Keane compared several methods to estimate surface fuel loading in western Montana: two widely used inventory techniques (planar intersect and fixed-area plot) and three methods that employ photographs as visual guides (photo load, photoload macroplot and photo series). We feel, however, that their study design was inadequate to evaluate...

  14. [Microscopic comparison of the miniscrew's surface used in orthodontics: before and after use].

    Science.gov (United States)

    Sebbar, M; Bourzgui, F; Lazrak, L; Aazzab, B; El Quars, F

    2012-11-01

    The aim of our work is to study the modifications affecting the surface condition of miniscrews retrieved from patients following an orthodontic treatment and comparing these miniscrews to unused ones. This study involved ten miniscrews placed in seven patients after orthodontic treatment for various indications. These miniscrews of the same manufacturer (Dual Top Anchor System® [Jeil Medical Corporation, Seoul, Korea]) were observed under optical microscope (Leica DM2500M) in order to examine their surface. Four new Miniscrews of different manufacturers, including the manufacturer of Miniscrews trademarks patients (Abso Anchor [Dentos, Daegu, South Korea] Infiniti [DB Orthodontics, Silsden, West Yorkshire, UK], Dual Top(®) [Jeil Medical Corporation, Seoul, Korea], IMTEC(®) [Ardmore, Okla]) were examined under the same microscope to compare with the used miniscrews. The study of the new miniscrews showed an irregular surface with machining and polishing defects, in the form of stripes that could constitute election's point for electrochemical attacks. Compared with the new one, the miniscrew used showed pitting corrosion attacks and cracks, mainly in the machining defects. These attacks were localized over the whole of miniscrews. It is suggested that improving the surface finish can increase the corrosion resistance of these miniscrews. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  15. Comparison of QLF and DIAGNOdent for quantification of smooth surface caries.

    Science.gov (United States)

    Shi, X Q; Tranaeus, S; Angmar-Månsson, B

    2001-01-01

    The aim was to compare the detection and quantification of smooth surface caries by KaVo DIAGNOdent and quantitative laser/light-induced fluorescence (QLF) using a laser and a lamp as two different light sources. On 40 premolar teeth extracted from adolescents, 71 non-cavitated approximal surfaces were assessed. For QLF, both mean and maximum fluorescence losses were registered. To provide a gold standard for verification, the teeth were then sectioned and lesion depth, stratified on a five-point scale, was determined by histopathology and microradiography. The correlation between the gold standard and the two methods was assessed by Spearman's rank correlation coefficient. The sensitivity and specificity of the methods for detection of smooth surface caries at D(3) level were also assessed. For lesion depth, correlation with the gold standard was similar for QLF and DIAGNOdent: about 0.85. With respect to dentinal caries detection, sensitivity for DIAGNOdent was 0.75 and specificity 0.96, with a cut-off point of 9. The corresponding values for QLF were 0.94 and 1, with a cut-off value of 20% of fluorescence loss. Spearman's rank correlation coefficients for enamel mineral loss and QLF and DIAGNOdent, respectively, were 0.76 and 0.67. It was concluded that for quantification of smooth surface caries, the methods are of equal merit, but for scientific purposes, QLF offers the advantage of closer correlation with changes in mineral content.

  16. Comparison of the aerodynamics of bridge cables with helical fillets and a pattern-indented surface

    DEFF Research Database (Denmark)

    Kleissl, K.; Georgakis, C.T.

    2012-01-01

    of the surface pattern introduce a wind-angle of attack dependency that leads to a prediction of Den Hartog galloping instability. For yawed positions, flow transition was found to be independent of the relative cable-wind angle and therefore only governed by the along-wind flow velocity. The helically filleted...

  17. Application and comparison of band gap narrowing models for passivated phosphorus doped silicon surfaces

    Science.gov (United States)

    Kimmerle, Achim; Greulich, Johannes; Haug, Halvard; Wolf, Andreas

    2016-01-01

    In this work, the recently proposed band-gap narrowing model by Yan and Cuevas [J. Appl. Phys. 114, 044508 (2013)] is evaluated by simulations of the recombination pre-factor J0 of highly phosphorus doped, passivated crystalline silicon surfaces, which are particularly relevant for solar cell applications. The results were fitted to experimental J0 data measured on a large range of samples exhibiting different dopant profiles and passivation coatings, both for planar and textured surfaces. For each sample, the surface recombination velocity parameter Sp was extracted by fitting the simulation results to the experimental data. We show that the Yan and Cuevas' model developed for Fermi-Dirac statistics leads to a smooth and monotonically increasing curve for Sp as a function of the surface dopant concentration Nsurf, for both investigated passivation layers. We provide a parameterization for this relation and compare the findings with those obtained with the widely used model by Schenk [J. Appl. Phys. 84, 3684 (1998)]. On the other hand, we show that the apparent band gap narrowing of Yan and Cuevas developed for use with Boltzmann statistics cannot be used to describe the experimental data, requiring unphysical negative Sp values for high Nsurf.

  18. Step-height measurements on sand surfaces: A comparison between optical scanner and coordinate measuring machine

    DEFF Research Database (Denmark)

    Mohaghegh, Kamran; Yazdanbakhsh, Seyed Alireza; Tiedje, Niels Skat

    2016-01-01

    the same routine to touch the different positions on the polygonised mesh. Each measurement was repeated 5 times. The results of step height measurements on sand surfaces showed a maximum error of ± 12 µm for CMM, while scanner shows only ± 4 µm. Generally speaking, optical step height values were measured...

  19. Near-surface wind speed statistical distribution: comparison between ECMWF System 4 and ERA-Interim

    Science.gov (United States)

    Marcos, Raül; Gonzalez-Reviriego, Nube; Torralba, Verónica; Cortesi, Nicola; Young, Doo; Doblas-Reyes, Francisco J.

    2017-04-01

    In the framework of seasonal forecast verification, knowing whether the characteristics of the climatological wind speed distribution, simulated by the forecasting systems, are similar to the observed ones is essential to guide the subsequent process of bias adjustment. To bring some light about this topic, this work assesses the properties of the statistical distributions of 10m wind speed from both ERA-Interim reanalysis and seasonal forecasts of ECMWF system 4. The 10m wind speed distribution has been characterized in terms of the four main moments of the probability distribution (mean, standard deviation, skewness and kurtosis) together with the coefficient of variation and goodness of fit Shapiro-Wilks test, allowing the identification of regions with higher wind variability and non-Gaussian behaviour at monthly time-scales. Also, the comparison of the predicted and observed 10m wind speed distributions has been measured considering both inter-annual and intra-seasonal variability. Such a comparison is important in both climate research and climate services communities because it provides useful climate information for decision-making processes and wind industry applications.

  20. Comparison of methods for quantifying surface sublimation over seasonally snow-covered terrain

    Science.gov (United States)

    Sexstone, Graham A.; Clow, David W.; Stannard, David I.; Fassnacht, Steven R.

    2016-01-01

    Snow sublimation can be an important component of the snow-cover mass balance, and there is considerable interest in quantifying the role of this process within the water and energy balance of snow-covered regions. In recent years, robust eddy covariance (EC) instrumentation has been used to quantify snow sublimation over snow-covered surfaces in complex mountainous terrain. However, EC can be challenging for monitoring turbulent fluxes in snow-covered environments because of intensive data, power, and fetch requirements, and alternative methods of estimating snow sublimation are often relied upon. To evaluate the relative merits of methods for quantifying surface sublimation, fluxes calculated by the EC, Bowen ratio–energy balance (BR), bulk aerodynamic flux (BF), and aerodynamic profile (AP) methods and their associated uncertainty were compared at two forested openings in the Colorado Rocky Mountains. Biases between methods are evaluated over a range of environmental conditions, and limitations of each method are discussed. Mean surface sublimation rates from both sites ranged from 0.33 to 0.36 mm day−1, 0.14 to 0.37 mm day−1, 0.10 to 0.17 mm day−1, and 0.03 to 0.10 mm day−1 for the EC, BR, BF and AP methods, respectively. The EC and/or BF methods are concluded to be superior for estimating surface sublimation in snow-covered forested openings. The surface sublimation rates quantified in this study are generally smaller in magnitude compared with previously published studies in this region and help to refine sublimation estimates for forested openings in the Colorado Rocky Mountains.

  1. Secure base stations

    NARCIS (Netherlands)

    Bosch, Peter; Brusilovsky, Alec; McLellan, Rae; Mullender, Sape; Polakos, Paul

    2009-01-01

    With the introduction of the third generation (3G) Universal Mobile Telecommunications System (UMTS) base station router (BSR) and fourth generation (4G) base stations, such as the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Evolved Node B (eNB), it has become important to se

  2. SPS rectifier stations

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    The first of the twelves SPS rectifier stations for the bending magnets arrived at CERN at the end of the year. The photograph shows a station with the rectifiers on the left and in the other three cubicles the chokes, capacitors and resistor of the passive filter.

  3. "Inventive" Learning Stations

    Science.gov (United States)

    Jarrett, Olga

    2010-01-01

    Learning stations can be used for myriad purposes--to teach concepts, integrate subject matter, build interest, and allow for inquiry--the possibilities are limited only by the imagination of the teacher and the supplies available. In this article, the author shares suggestions and a checklist for setting up successful learning stations. In…

  4. "Inventive" Learning Stations

    Science.gov (United States)

    Jarrett, Olga

    2010-01-01

    Learning stations can be used for myriad purposes--to teach concepts, integrate subject matter, build interest, and allow for inquiry--the possibilities are limited only by the imagination of the teacher and the supplies available. In this article, the author shares suggestions and a checklist for setting up successful learning stations. In…

  5. Meyrin Petrol Station

    CERN Multimedia

    2006-01-01

    Please note that the Meyrin petrol station will be closed for maintenance work on Tuesday 19 and Wednesday 20 December 2006. If you require petrol during this period we invite you to use the Prévessin petrol station, which will remain open. TS-IC-LO Section Tel.: 77039 - 73793

  6. Kinetics of hybridization on surface oligonucleotide microchips: theory, experiment, and comparison with hybridization on gel-based microchips.

    Science.gov (United States)

    Sorokin, N V; Chechetkin, V R; Pan'kov, S V; Somova, O G; Livshits, M A; Donnikov, M Y; Turygin, A Y; Barsky, V E; Zasedatelev, A S

    2006-08-01

    The optimal design of oligonucleotide microchips and efficient discrimination between perfect and mismatch duplexes strongly depend on the external transport of target DNA to the cells with immobilized probes as well as on respective association and dissociation rates at the duplex formation. In this paper we present the relevant theory for hybridization of DNA fragments with oligonucleotide probes immobilized in the cells on flat substrate. With minor modifications, our theory also is applicable to reaction-diffusion hybridization kinetics for the probes immobilized on the surface of microbeads immersed in hybridization solution. The main theoretical predictions are verified with control experiments. Besides that, we compared the characteristics of the surface and gel-based oligonucleotide microchips. The comparison was performed for the chips printed with the same pin robot, for the signals measured with the same devices and processed by the same technique, and for the same hybridization conditions. The sets of probe oligonucleotides and the concentrations of probes in respective solutions used for immobilization on each platform were identical as well. We found that, despite the slower hybridization kinetics, the fluorescence signals and mutation discrimination efficiency appeared to be higher for the gel-based microchips with respect to their surface counterparts even for the relatively short hybridization time about 0.5-1 hour. Both the divergence between signals for perfects and the difference in mutation discrimination efficiency for the counterpart platforms rapidly grow with incubation time. In particular, for hybridization during 3 h the signals for gel-based microchips surpassed their surface counterparts in 5-20 times, while the ratios of signals for perfect-mismatch pairs for gel microchips exceeded the corresponding ratios for surface microchips in 2-4 times. These effects may be attributed to the better immobilization efficiency and to the higher

  7. Comparison of Cronobacter sakazakii from Agra region grown in biofilms, agar surface associated and planktonic mode by proteomic analysis

    Directory of Open Access Journals (Sweden)

    Garima Sharma

    2013-01-01

    Full Text Available Context: Cronobacter sakazakii is an emerging food borne pathogen that causes severe meningitis, meningoencephalitis, sepsis, and necrotizing enterocolitis in neonates and infants, with a high fatality rate. Aims: The present paper is for the rapid detection of C. sakazakii from milk and milk products of Agra region via PCR method and comparison of C. sakazakii in biofilm, on agar surface and planktonic cells by proteomic analysis. Materials and Methods: In the present study, 55 samples of milk and milk products of the Agra region were analyzed. 200 isolates were obtained of which 11 were biochemically detected as C. sakazakii. The PCR targeting the ompA gene was used to amplify a 496 bp DNA segment unique to C. sakazakii, in order to confirm C. sakazakii isolates. The proteome was investigated to study the differential protein pattern expressed by biofilm, agar surface-associated and planktonic bacteria employing SDS-PAGE. Statistical Analysis: UN-SCAN-6.1 gel analysis software. Results: The primer pair ESSF and ESSR was successfully used to amplify a 469 bp DNA unique to C. sakazakii. Whole cell protein profiles of planktonic, biofilm and agar surface associated were characteristic. Conclusion: The cultural procedure for detection of C. sakazakii is laborious, taking up to 7 days for completion, whereas PCR combined with enrichment culturing can detect C. sakazakii in about 12 hours and thus has the potential to be used as a rapid tool for detecting its presence. Differential protein pattern of C. sakazakii cultivated in biofilm versus agar-surface-associated and planktonic cells were observed. Further understanding the role of specific proteins during the biofilm development should permit a better understanding of the mechanisms sustaining the proliferation and the resistance of bacteria on biotic surfaces.

  8. Heterogeneous Reactions of Surface-Adsorbed Catechol: A Comparison of Tropospheric Aerosol Surrogates

    Science.gov (United States)

    Hinrichs, R. Z.; Woodill, L. A.

    2009-12-01

    Surface-adsorbed organics can alter the chemistry of tropospheric solid-air interfaces, such as aerosol and ground level surfaces, thereby impacting photochemical cycles and altering aerosol properties. The nature of the surface can also influence the chemistry of the surface-adsorbed organic. We employed diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to monitor the adsorption of gaseous catechol on several tropospheric aerosol surrogates and to investigate the subsequent reactivity of adsorbed-catechol with nitrogen dioxide and, in separate preliminary experiments, ozone. Graphite, kaolinite, and sodium halide (NaF, NaCl, NaBr) powders served as carbonaceous, mineral and sea salt aerosol surrogates, respectively. Broad OH stretching bands for adsorbed catechol shifted to lower wavenumber with peak frequencies following the trend NaBr > NaCl > NaF ≈ kaolinite, consistent with the increasing basicity of the halide anions and basic Brønsted sites on kaolinite. The dark heterogeneous reaction of NO2 with NaCl-adsorbed catechol at relative humidity (RH) 4-nitrocatechol and oxidation forming 1,2-benzoquinone and the ring cleavage product muconic acid, with product yields of 88%, 8%, and 4%, respectively. 4-Nitrocatechol was the dominant product for catechol adsorbed on NaF and kaolinite, while NaBr-adsorbed catechol produced less 4-nitrocatechol and more 1,2-benzoquinone and muconic acid. For all three sodium halides, the reactions of NO2 with adsorbed catechol were orders of magnitude faster than between NO2 and each NaX substrate. 4-Nitrocatechol rates and product yields were consistent with the relative ability of each substrate to enhance the deprotonated nature of adsorbed-catechol. Increasing the relative humidity caused the rate of each product channel to decrease and also altered the product branching ratios. Most notably, 1,2-benzoquinone formation decreased significantly even at 13% RH. The dramatic reactivity of surface

  9. PAHs composition of surface marine sediments: a comparison to potential local sources in Todos Santos Bay, B.C., Mexico.

    Science.gov (United States)

    Macías-Zamora, J V; Mendoza-Vega, E; Villaescusa-Celaya, J A

    2002-01-01

    The analysis of the 16 polyaromatic hydrocarbons (PAHs) listed as priority pollutants by EPA, was carried out on surface sediments at 32 stations at Todos Santos Bay, Baja California, Mexico. The purpose was to investigate concentration levels, distribution patterns and relate them to three suspected local sources. The PAHs composition of car exhaust, grass and shrubs combustion, and asphalt and tire dust, were all compared to the relative abundance of PAHs signature found on marine sediments of the bay. We used GC-MS analysis in selected ion monitoring (SIM) mode. The total concentration found was low (from 7.6 to 813 ng/g of dry sediment. The average concentration was 96 ng/g). PAHs concentration was somewhat correlated (r = 0.612; P Todos Santos Canyon. The largest concentrations found were those of fluoranthene (120.6 ng/g), Indene(1,2,3-c,d)pyrene (115.6 ng/g) and pyrene (109.9 ng/g). Percentagewise, the main components were PAHs with three and four rings. Several indexes were used to investigate origins including simple PAH ratios and ternary plots. These indexes and plots suggest the main origin as a combination of urban air and wood and brush fires with little influence of oil.

  10. The Roman stational liturgy

    Directory of Open Access Journals (Sweden)

    Janusz Mieczkowski

    2012-03-01

    Full Text Available The papal stational liturgy in Rome was a particular kind of worship service from the Christian Antiquity to the XIV century. Its essential elements are four. Its always took place under the leadership of the pope or his representative. This form of liturgy was mobile: it was celebrated in different basilicas or churches of Rome. Third, the choice of church depended on the feast, liturgical seasons or commemoration being celebrated. Fourth, the stational liturgy was the urban liturgical celebration of the day. The highpoint of this system was Lent. Throughout the entire system Church of Rome manifested its own unity. The station was usually the Pope’s solemn mass in the stational church for the whole city. But on certain days in the year the Pope went in another church (collecta, from which a solemn procession was made to the stational church.

  11. Central Station Design Options

    DEFF Research Database (Denmark)

    2011-01-01

    The purpose of EDISON Work Package 4.1 is the evaluation of possible Central (charging) Stations design options for making possible the public charging of Electric Vehicles (EVs). A number of scenarios for EVs are assessed, with special emphasis on the options of Fast Charging and Battery Swapping....... The work identifies the architecture, sizing and siting of prospective Central Stations in Denmark, which can be located at shopping centers, large car parking lots or gas stations. Central Stations are planned to be integrated in the Danish distribution grid. The Danish island of Bornholm, where a high.......g. due to vandalism, the charge supply circuit is disconnected. More electrical vehicles on the market are capable today of quick charging up to 50 kW power level. The feasibility of Central Stations with fast charging/swapping option, their capacity, design, costs and grid impact, as well as battery...

  12. Comparison characteristics of surface acoustic waves propagating on LGT and quartz substrates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guowei; SHI Wenkang; JI Xiaojun; HAN Tao

    2004-01-01

    For comprehending the propagation characteristics of surface acoustic waves (SAW) on novel piezoelectric crystal Langatate (LGT), the numerical analysis of the most important propagation characteristics of surface acoustic waves (SAW) on LGT are presented and compared with that of quartz. The results are that the phase velocity on LGT is generally about 1000 m/s slower than that on quartz; there are zero temperature cuts and pure mode directions on LGT; the electromechanical coupling coefficient (K2) of LGT is larger than that of quartz. The results show that LGT has lower propagation velocity, higher electromechanical coupling coefficient, good temperature stability and other good characteristic. The results also show that there are somewhat deviations with different material constants, especially, the temperature coefficient of frequency.

  13. Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    L. D. Naidu

    2015-01-01

    Full Text Available The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF has been chosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential minerals required for human body, consuming of lower energy, and no usage of any chemicals. The prominent parameters of surface water and macro/microminerals of treated water have been analyzed. It is shown that NF is better in producing healthy water with high flux by consuming low energy.

  14. Comparison of SMOS and Aquarius Sea Surface Salinity and Analysis of Possible Causes for the Differences

    Science.gov (United States)

    Dinnat, E. P.; Boutin, J.; Yin, X.; Le Vine, D. M.; Waldteufel, P.; Vergely, J. -L.

    2014-01-01

    Two ongoing space missions share the scientific objective of mapping the global Sea Surface Salinity (SSS), yet their observations show significant discrepancies. ESA's Soil Moisture and Ocean Salinity (SMOS) and NASA's Aquarius use L-band (1.4 GHz) radiometers to measure emission from the sea surface and retrieve SSS. Significant differences in SSS retrieved by both sensors are observed, with SMOS SSS being generally lower than Aquarius SSS, except for very cold waters where SMOS SSS is the highest overall. Figure 1 is an example of the difference between the SSS retrieved by SMOS and Aquarius averaged over one month and 1 degree in longitude and latitude. Differences are mostly between -1 psu and +1 psu (psu, practical salinity unit), with a significant regional and latitudinal dependence. We investigate the impact of the vicarious calibration and some components of the retrieval algorithm used by both mission on these differences.

  15. Comparison of Surface-enhanced Raman Scattering Spectra of Two Kinds of Silver Nanoplate Films

    Institute of Scientific and Technical Information of China (English)

    TAO Jin-long; TANG Bin; XU Shu-ping; PAN Ling-yun; XU Wei-qing

    2012-01-01

    Surface-enhanced Raman scattering(SERS) spectra of different silver nanoplate self-assembled films at different excitation wavelengths were fairly compared.Shape conversion from silver nanoprisms to nanodisks on slides was in situ carried out.The SERS spectra of 4-mercaptopyridine(4-MPY) on these anisotropic silver nanoparticle self-assembled films present that strong enhancement appeared when the excitation line and the surface plasmon resonance(SPR) band of silver substrate overlapped.In this model,the influence of the crystal planes of silver nanoplates on SERS enhancement could be ignored because the basal planes were nearly unchanged in two kinds of silver nanoplate self-assembled films.

  16. Comparison of anti-fouling surface coatings for applications in bacteremia diagnostics.

    Science.gov (United States)

    Boardman, Anna K; Allison, Sandra; Sharon, Andre; Sauer-Budge, Alexis F

    2013-01-01

    To accurately diagnose microbial infections in blood, it is essential to recover as many microorganisms from a sample as possible. Unfortunately, recovering such microorganisms depends significantly on their adhesion to the surfaces of diagnostic devices. Consequently, we sought to minimize the adhesion of methicillin-sensitive Staphylococcus aureus (MSSA) to the surface of polypropylene- and acrylic-based bacteria concentration devices. These devices were treated with 11 different coatings having various charges and hydrophobicities. Some coatings promoted bacterial adhesion under centrifugation, whereas others were more likely to prevent it. Experiments were run using a simple buffer system and lysed blood, both inoculated with MSSA. Under both conditions, Hydromer's 7-TS-13 and Aqua65JL were most effective at reducing bacterial adhesion.

  17. Continuous vs. pulsating flow boiling. Part 2: Statistical comparison using response surface methodology

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Elmegaard, Brian; Meyer, Knud Erik

    2016-01-01

    Response surface methodology is used to investigate an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The flow pulsations are introduced by a flow modulating expansion device and compared with the baseline continuous flow provided by a stepper-motor exp......Response surface methodology is used to investigate an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The flow pulsations are introduced by a flow modulating expansion device and compared with the baseline continuous flow provided by a stepper...... pulsations is statistically significant in terms of the time-averaged flow boiling heat transfer coefficient. The cycle time range from 1 s to 9 s for the pulsations. The results show that the effect of fluid flow pulsations is statistically significant, disregarding the lowest heat flux measurements...

  18. Photoemission from Low Work Function Coated Metal Surfaces A Comparison of Theory to Experiment

    CERN Document Server

    Jensen, Kevin; Moody, Nathan A

    2005-01-01

    The development of rugged and/or self rejuvenating photocathodes with high quantum efficiency (QE) using the longest wavelength drive laser is of paramount importance for RF photo-injectors for high power FELs and accelerators. We report on our program to develop advanced photocathodes and to develop and validate models of photoemission from coated metals to analyze experimental data,* provide emission models usable by beam simulation codes,** and project performance. The model accounts for the effects of laser heating, thermal evolution, surface conditions, laser parameters, and material characteristics, and predicts current distribution and QE. The photoemission and QE from metals and dispenser photocathodes is evaluated: the later introduces complications such as coverage non-uniformity and field enhancement. The performance of the models is compared to our experimental results for dispenser photocathodes and cesiated surfaces (e.g., tungsten, silver, etc.) in which the time-dependent models are shown to a...

  19. Comparison of Super Stuff and paraffin wax bolus in radiation therapy of irregular surfaces.

    Science.gov (United States)

    Humphries, S M; Boyd, K; Cornish, P; Newman, F D

    1996-01-01

    Irregular facial contours can make radiation therapy of head and neck tumors difficult. Isodose lines become skewed, making treatment planning complex. A traditional solution to this problem is the paraffin wax box bolus. Such a bolus is made to fit the irregular surface compensating for the topology and creating an even surface. The fabrication of a wax bolus can be a difficult and time-consuming process. A method that is simple and efficient has been devised. Super Stuff bolus can be easily molded and has approximately the same effect as a similar paraffin wax bolus. This was verified by irradiating a Rando head phantom with both a paraffin wax bolus and a Super Stuff bolus. Doses to various points of interest were measured with thermoluminescent dosimetry (TLD) chips (LiF). The particular case addressed is malignant melanoma of the nasal septum, but the technique described can be useful in the treatment of other sites as well.

  20. Comparison of deposited surface area of airborne ultrafine particles generated from two welding processes.

    Science.gov (United States)

    Gomes, J F; Albuquerque, P C; Miranda, Rosa M; Santos, Telmo G; Vieira, M T

    2012-09-01

    This article describes work performed on the assessment of the levels of airborne ultrafine particles emitted in two welding processes metal-active gas (MAG) of carbon steel and friction-stir welding (FSW) of aluminium in terms of deposited area in alveolar tract of the lung using a nanoparticle surface area monitor analyser. The obtained results showed the dependence from process parameters on emitted ultrafine particles and clearly demonstrated the presence of ultrafine particles, when compared with background levels. The obtained results showed that the process that results on the lower levels of alveolar-deposited surface area is FSW, unlike MAG. Nevertheless, all the tested processes resulted in important doses of ultrafine particles that are to be deposited in the human lung of exposed workers.

  1. Capturing the surface texture and shape of pollen: a comparison of microscopy techniques.

    Directory of Open Access Journals (Sweden)

    Mayandi Sivaguru

    Full Text Available Research on the comparative morphology of pollen grains depends crucially on the application of appropriate microscopy techniques. Information on the performance of microscopy techniques can be used to inform that choice. We compared the ability of several microscopy techniques to provide information on the shape and surface texture of three pollen types with differing morphologies. These techniques are: widefield, apotome, confocal and two-photon microscopy (reflected light techniques, and brightfield and differential interference contrast microscopy (DIC (transmitted light techniques. We also provide a first view of pollen using super-resolution microscopy. The three pollen types used to contrast the performance of each technique are: Croton hirtus (Euphorbiaceae, Mabea occidentalis (Euphorbiaceae and Agropyron repens (Poaceae. No single microscopy technique provided an adequate picture of both the shape and surface texture of any of the three pollen types investigated here. The wavelength of incident light, photon-collection ability of the optical technique, signal-to-noise ratio, and the thickness and light absorption characteristics of the exine profoundly affect the recovery of morphological information by a given optical microscopy technique. Reflected light techniques, particularly confocal and two-photon microscopy, best capture pollen shape but provide limited information on very fine surface texture. In contrast, transmitted light techniques, particularly differential interference contrast microscopy, can resolve very fine surface texture but provide limited information on shape. Texture comprising sculptural elements that are spaced near the diffraction limit of light (~250 nm; NDL presents an acute challenge to optical microscopy. Super-resolution structured illumination microscopy provides data on the NDL texture of A. repens that is more comparable to textural data from scanning electron microscopy than any other optical

  2. A blended land emissivity product from the Inter-Comparison of different Land Surface Emissivity Estimates

    Science.gov (United States)

    Norouzi, H.; Temimi, M.; Khanbilvardi, R.

    2012-12-01

    Passive microwave observations are routinely used to estimate rain rate, cloud liquid water, and total precipitable water. In order to have accurate estimations from microwave, the contribution of the surface should be accounted for. Over land, due to the complex interaction between the microwave signal and the soil surface, retrieval of land surface emissivity and other surface and subsurface parameters is not straightforward. Several microwave emissivity products from various microwave sensors have been proposed. However, lack of ground truth measurements makes the validation of these products difficult. This study aims to inter-compare several available emissivity products over land and ultimately proposes a unique blended product that overcomes the flaws of each individual product. The selected products are based on observations from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), the Special Sensor Microwave Imager (SSM/I), the Advanced Microwave Sounding unit (AMSU), and the Special Sensor Microwave Imager/Sounder (SSMIS). In retrieval of emissivities from these sensors different methods and ancillary data have been used. Some inherent discrepancies between the selected products can be introduced by as the difference in geometry in terms of incident angle, spectral response, and the foot print size which can affect the estimations. Moreover, ancillary data especially skin temperature and cloud mask cover can cause significant discrepancies between various estimations. The time series and correlation between emissivity maps are explored to assess the consistency of emissivity variations with geophysical variable such as snow, precipitation and drought. Preliminary results reveal that inconsistency between products varies based on land cover type due to penetration depth effect and ancillary data. Six years of estimations are employed in this research study, and a global blended emissivity estimations based on all product with minimal discrepancies

  3. Comparison of pulse height spectra on CsI(T1)/PIN photodiode radiation detector due to surface encapsulant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Soo; Ha, Jang Ho; Jeong, Man Hee; Kim, Young Soo; Kim, Dong Jin; Cho, Woo Jin; Choi, Hyo Jeong [Korea Atomic Energy Research Institute, Seoul (Korea, Republic of); Cho, Seung Yeon [Environmental Health Center, Yonsei University, Seoul (Korea, Republic of)

    2014-04-15

    Scintillation crystal converts the energy deposited by an X-ray or gamma ray to light. Usually this scintillation light is collected, converted to electrons and amplified by an photomultiplier tube (PMT). The PMT has the drawbacks of being bulky and requiring a high voltage (HV) to operate it. This scinitllation light can also be collected in a solid state photo-detector, such as a silicon PIN photodiode and an avanlanche photodiode. PIN photodiode, which have 10 mm X 10 mm{sup 2} active area, were fabricated with anti-reflective coating and match with CsI(Tl) scintillator. In this study, radiation reasonabilities were compared with and without surface encapsulant epoxy. Silicon PIN Photodiodes were fabricated with AR coating. To match with CsI(Tl) scintillator, surface encapsulant was applied on the PIN photodiodes. Leakage currents for all the PIN photodiodes show several nA up to 100 V. The pulse height spectra and comparison of the CsI(Tl)PIN photodiode in case of surface encapsulation on PIN photodiode will be presented at the conference.

  4. On the Electrodeposition of Ca-P Coatings on Nitinol Alloy: A Comparison Between Different Surface Modification Methods

    Science.gov (United States)

    Etminanfar, M. R.; Khalil-Allafi, J.

    2016-02-01

    In this study, a combination of surface modification process and the electrochemical deposition of Ca-P coatings was used for the modification of the Nitinol shape memory alloy. DSC, SEM, GIB-XRD, FT-Raman, XPS, and FTIR measurements were performed for the characterization of the samples. Results indicated that chemical etching and boiling of the samples in distilled water formed TiO film on the surface. After the chemical modification, subsequent aging of the sample, at 470 °C for 30 min, converted the oxide film to a stable structure of titanium dioxide. In that case, the treated substrate indicated a superelastic behavior. At the same electrochemical condition, the treated substrate revealed more stable and uniform Ca-P coatings in comparison with the abraded Nitinol substrate. This difference was attributed to the presence of hydroxyl groups on the titanium dioxide surface. Also, after soaking the sample in SBF, the needle-like coating on the treated substrate was completely covered with the hydroxyapatite phase which shows a good bioactivity of the coating.

  5. Comparison of optimization techniques for MRR and surface roughness in wire EDM process for gear cutting

    Directory of Open Access Journals (Sweden)

    K.D. Mohapatra

    2016-11-01

    Full Text Available The objective of the present work is to use a suitable method that can optimize the process parameters like pulse on time (TON, pulse off time (TOFF, wire feed rate (WF, wire tension (WT and servo voltage (SV to attain the maximum value of MRR and minimum value of surface roughness during the production of a fine pitch spur gear made of copper. The spur gear has a pressure angle of 20⁰ and pitch circle diameter of 70 mm. The wire has a diameter of 0.25 mm and is made of brass. Experiments were conducted according to Taguchi’s orthogonal array concept with five factors and two levels. Thus, Taguchi quality loss design technique is used to optimize the output responses carried out from the experiments. Another optimization technique i.e. desirability with grey Taguchi technique has been used to optimize the process parameters. Both the optimized results are compared to find out the best combination of MRR and surface roughness. A confirmation test was carried out to identify the significant improvement in the machining performance in case of Taguchi quality loss. Finally, it was concluded that desirability with grey Taguchi technique produced a better result than the Taguchi quality loss technique in case of MRR and Taguchi quality loss gives a better result in case of surface roughness. The quality of the wire after the cutting operation has been presented in the scanning electron microscopy (SEM figure.

  6. Comparison pesticide residue levels in the surface of Bertam River in Cameron Highlands, Pahang

    Energy Technology Data Exchange (ETDEWEB)

    Haron, S. H., E-mail: ismail@ukm.edu.my; Ismail, B. S., E-mail: sthumaira@yahoo.com [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 UKM, Bangi, Selangor (Malaysia)

    2015-09-25

    The presence of pesticide residues in the surface water of Bertam River in the agricultural areas of Cameron Highlands in Pahang, Malaysia was monitored from May to October 2014. The sampling sites were located at 10 sampling points along the Bertam River in the vegetable planting areas. The extraction method of the pesticide (organophosphate/pyrethroid) from the river samples used solid phase extraction followed by gas chromatography (with electron capture detector, ECD). Insecticides, cypermethrin and chlorpyrifos were found in the surface water of Bertam River. High level concentrations of those insecticides in the river were observed during the period from May to October 2014, a period which included both seasons (wet and dry seasons). The highest concentration of 2.66 µg/mL and 1.23 µg/mL of cypermethrin was observed during the wet and dry seasons respectively. This could be due to the frequent usage of the above-mentioned insecticides coupled with contamination that could have originated from the application sites. Meanwhile, the lowest concentration detected in the surface water was chlorpyrifos (0.11 µg/mL and 0.17 µg/mL) during the dry and wet seasons, respectively.

  7. Comparison of two surface temperature measurement using thermocouples and infrared camera

    Directory of Open Access Journals (Sweden)

    Michalski Dariusz

    2017-01-01

    Full Text Available This paper compares two methods applied to measure surface temperatures at an experimental setup designed to analyse flow boiling heat transfer. The temperature measurements were performed in two parallel rectangular minichannels, both 1.7 mm deep, 16 mm wide and 180 mm long. The heating element for the fluid flowing in each minichannel was a thin foil made of Haynes-230. The two measurement methods employed to determine the surface temperature of the foil were: the contact method, which involved mounting thermocouples at several points in one minichannel, and the contactless method to study the other minichannel, where the results were provided with an infrared camera. Calculations were necessary to compare the temperature results. Two sets of measurement data obtained for different values of the heat flux were analysed using the basic statistical methods, the method error and the method accuracy. The experimental error and the method accuracy were taken into account. The comparative analysis showed that although the values and distributions of the surface temperatures obtained with the two methods were similar but both methods had certain limitations.

  8. Comparison pesticide residue levels in the surface of Bertam River in Cameron Highlands, Pahang

    Science.gov (United States)

    Haron, S. H.; Ismail B., S.

    2015-09-01

    The presence of pesticide residues in the surface water of Bertam River in the agricultural areas of Cameron Highlands in Pahang, Malaysia was monitored from May to October 2014. The sampling sites were located at 10 sampling points along the Bertam River in the vegetable planting areas. The extraction method of the pesticide (organophosphate/pyrethroid) from the river samples used solid phase extraction followed by gas chromatography (with electron capture detector, ECD). Insecticides, cypermethrin and chlorpyrifos were found in the surface water of Bertam River. High level concentrations of those insecticides in the river were observed during the period from May to October 2014, a period which included both seasons (wet and dry seasons). The highest concentration of 2.66 µg/mL and 1.23 µg/mL of cypermethrin was observed during the wet and dry seasons respectively. This could be due to the frequent usage of the above-mentioned insecticides coupled with contamination that could have originated from the application sites. Meanwhile, the lowest concentration detected in the surface water was chlorpyrifos (0.11 µg/mL and 0.17 µg/mL) during the dry and wet seasons, respectively.

  9. Comparison of contact angle hysteresis of different probe liquids on the same solid surface.

    Science.gov (United States)

    Chibowski, Emil; Jurak, Malgorzata

    2013-02-01

    Advancing and receding contact angles of water, formamide and diiodomethane were measured on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) layers deposited on three different solid supports-glass, mica and poly(methyl methacrylate). Up to five statistical monolayers were deposited on the surfaces by spreading DPPC solution. It was found that even on five statistical DPPC monolayers, the hysteresis of a given liquid depends on the kind of solid support. Also on the same solid support the contact angle hysteresis is different for each probe liquid used. The AFM images show that the heights of roughness of the DPPC films cannot be the primary cause of the observed hysteresis because the heights are too small to cause the observed hystereses. It is believed that the hysteresis is due to the liquid film present right behind the three-phase solid surface/liquid drop/gas (vapour) contact line and the presence of Derjaguin pressure. The value of contact angle hysteresis depends on both the solid surface and liquid properties as well as on intermolecular interactions between them.

  10. Comparison of Innovative Molecular Approaches and Standard Spore Assays for Assessment of Surface Cleanliness ▿

    Science.gov (United States)

    Cooper, Moogega; La Duc, Myron T.; Probst, Alexander; Vaishampayan, Parag; Stam, Christina; Benardini, James N.; Piceno, Yvette M.; Andersen, Gary L.; Venkateswaran, Kasthuri

    2011-01-01

    A bacterial spore assay and a molecular DNA microarray method were compared for their ability to assess relative cleanliness in the context of bacterial abundance and diversity on spacecraft surfaces. Colony counts derived from the NASA standard spore assay were extremely low for spacecraft surfaces. However, the PhyloChip generation 3 (G3) DNA microarray resolved the genetic signatures of a highly diverse suite of microorganisms in the very same sample set. Samples completely devoid of cultivable spores were shown to harbor the DNA of more than 100 distinct microbial phylotypes. Furthermore, samples with higher numbers of cultivable spores did not necessarily give rise to a greater microbial diversity upon analysis with the DNA microarray. The findings of this study clearly demonstrated that there is not a statistically significant correlation between the cultivable spore counts obtained from a sample and the degree of bacterial diversity present. Based on these results, it can be stated that validated state-of-the-art molecular techniques, such as DNA microarrays, can be utilized in parallel with classical culture-based methods to further describe the cleanliness of spacecraft surfaces. PMID:21652744

  11. Comparison of innovative molecular approaches and standard spore assays for assessment of surface cleanliness.

    Science.gov (United States)

    Cooper, Moogega; La Duc, Myron T; Probst, Alexander; Vaishampayan, Parag; Stam, Christina; Benardini, James N; Piceno, Yvette M; Andersen, Gary L; Venkateswaran, Kasthuri

    2011-08-01

    A bacterial spore assay and a molecular DNA microarray method were compared for their ability to assess relative cleanliness in the context of bacterial abundance and diversity on spacecraft surfaces. Colony counts derived from the NASA standard spore assay were extremely low for spacecraft surfaces. However, the PhyloChip generation 3 (G3) DNA microarray resolved the genetic signatures of a highly diverse suite of microorganisms in the very same sample set. Samples completely devoid of cultivable spores were shown to harbor the DNA of more than 100 distinct microbial phylotypes. Furthermore, samples with higher numbers of cultivable spores did not necessarily give rise to a greater microbial diversity upon analysis with the DNA microarray. The findings of this study clearly demonstrated that there is not a statistically significant correlation between the cultivable spore counts obtained from a sample and the degree of bacterial diversity present. Based on these results, it can be stated that validated state-of-the-art molecular techniques, such as DNA microarrays, can be utilized in parallel with classical culture-based methods to further describe the cleanliness of spacecraft surfaces.

  12. Comparison of surface vacuum ultraviolet emissions with resonance level number densities. I. Argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Boffard, John B., E-mail: jboffard@wisc.edu; Lin, Chun C. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Culver, Cody [Materials Science Program, University of Wisconsin, Madison, WI 53706 (United States); Wang, Shicong; Wendt, Amy E. [Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706 (United States); Radovanov, Svetlana; Persing, Harold [Varian Semiconductor Equipment, Applied Materials Inc., Gloucester, MA 01939 (United States)

    2014-03-15

    Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. The highly energetic photons can induce surface damage by driving surface reactions, disordering surface regions, and affecting bonds in the bulk material. In argon plasmas, the VUV emissions are due to the decay of the 1s{sub 4} and 1s{sub 2} principal resonance levels with emission wavelengths of 104.8 and 106.7 nm, respectively. The authors have measured the number densities of atoms in the two resonance levels using both white light optical absorption spectroscopy and radiation-trapping induced changes in the 3p{sup 5}4p→3p{sup 5}4s branching fractions measured via visible/near-infrared optical emission spectroscopy in an argon inductively coupled plasma as a function of both pressure and power. An emission model that takes into account radiation trapping was used to calculate the VUV emission rate. The model results were compared to experimental measurements made with a National Institute of Standards and Technology-calibrated VUV photodiode. The photodiode and model results are in generally good accord and reveal a strong dependence on the neutral gas temperature.

  13. A comparison of various surface charge transfer hole doping of graphene grown by chemical vapour deposition

    Science.gov (United States)

    Chandramohan, S.; Seo, Tae Hoon; Janardhanam, V.; Hong, Chang-Hee; Suh, Eun-Kyung

    2017-10-01

    Charge transfer doping is a renowned route to modify the electrical and electronic properties of graphene. Understanding the stability of potentially important charge-transfer materials for graphene doping is a crucial first step. Here we present a systematic comparison on the doping efficiency and stability of single layer graphene using molybdenum trioxide (MoO3), gold chloride (AuCl3), and bis(trifluoromethanesulfonyl)amide (TFSA). Chemical dopants proved to be very effective, but MoO3 offers better thermal stability and device fabrication compatibility. Single layer graphene films with sheet resistance values between 100 and 200 ohm/square were consistently produced by implementing a two-step growth followed by doping without compromising the optical transmittance.

  14. Comparison of airborne and surface particulate size distributions in specific Hanford Nuclear Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Ottley, D.B.

    1995-05-01

    Settled dust from nuclear operations may be contaminated with radionuclides and become resuspended and subsequently breathed. This is the predominate radionuclide inhalation hazard scenario in nuclear facilities that have been deactivated and no longer have liquid in their process systems that may become directly airborne in accident situations. Comparisons were made between indoor ambient airborne particulate size distribution and that of resuspended dust that could become contaminated and subsequently airborne during decommissioning operations at selected nuclear facilities on the Hanford Site. Results indicate that only 5% of the particles, by count, above the breathing zone are greater than ten (10) {mu}m in size and that the particulates that could be resuspended into the breathing zone had a mean aerodynamic equivalent diameter of four (4) {mu}m or less.

  15. The Martian surface radiation environment – a comparison of models and MSL/RAD measurements

    Directory of Open Access Journals (Sweden)

    Matthiä Daniel

    2016-01-01

    Full Text Available Context: The Radiation Assessment Detector (RAD on the Mars Science Laboratory (MSL has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models. Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation exposure on the Martian surface complementing the RAD sensitive range and, at the same time, validate the results with the experimental data, where applicable. Such validated models can be used to predict dose rates for future manned missions as well as for performing shield optimization studies. Methods: Several particle transport models (GEANT4, PHITS, HZETRN/OLTARIS were used to predict the particle flux and the corresponding radiation environment caused by galactic cosmic radiation on Mars. From the calculated particle spectra the dose rates on the surface are estimated. Results: Calculations of particle spectra and dose rates induced by galactic cosmic radiation on the Martian surface are presented. Although good agreement is found in many cases for the different transport codes, GEANT4, PHITS, and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude discrepancies in certain particle spectra. We have found that RAD data is helping to make better choices of input parameters and physical models. Elements of these validated models can be applied to more detailed studies on how the radiation environment is influenced by solar modulation, Martian atmosphere and soil, and changes due to the Martian seasonal pressure cycle. By extending the range of the calculated particle

  16. Sensor Emplacement Techniques and Seismic Noise Analysis for USArray Transportable Array Seismic Stations

    Science.gov (United States)

    Frassetto, A.; Busby, R. W.; Hafner, K.; Woodward, R.; Sauter, A.

    2013-12-01

    In preparation for the upcoming deployment of EarthScope's USArray Transportable Array (TA) in Alaska, the National Science Foundation (NSF) has supported exploratory work on seismic station design, sensor emplacement, and communication concepts appropriate for this challenging high-latitude environment. IRIS has installed several experimental stations to evaluate different sensor emplacement schemes both in Alaska and in the lower-48 of the U.S. The goal of these tests is to maintain or enhance a station's noise performance while minimizing its footprint and the weight of the equipment, materials, and overall expense required for its construction. Motivating this approach are recent developments in posthole broadband seismometer design and the unique conditions for operating in Alaska, where there are few roads, cellular communications are scarce, most areas are only accessible by small plane or helicopter, and permafrost underlies much of the state. We will review the methods used for directly emplacing broadband seismometers in comparison to the current methods used for the lower-48 TA. These new methods primarily focus on using a portable drill to make a bored hole three to five meters, beneath the active layer of the permafrost, or by coring 1-2 meters deep into surface bedrock. Both methods are logistically effective in preliminary trials. Subsequent station performance has been assessed quantitatively using probability density functions summed from power spectral density estimates. These are calculated for the continuous time series of seismic data recorded for each channel of the seismometer. There are five test stations currently operating in Alaska. One was deployed in August 2011 and the remaining four in October 2012. Our results show that the performance of seismometers in Alaska with auger-hole or core-hole installations can sometimes exceed that of the quietest TA stations in the lower-48, particularly horizontal components at long periods. A

  17. Comparison of the terminal fall velocity, surface roughness and erosion threshold for volcanic particles.

    Science.gov (United States)

    Douillet, G. A.; Seybold, L.; Rasmussen, K. R.; Kueppers, U.,; Lo Castro, D.; Dingwell, D. B.

    2012-04-01

    Pyroclasts are particles emitted during explosive volcanic eruptions. They exhibit highly variable porosities, shapes, and densities. As such, their behaviors differ from the wind-blown and fluvial sand usually studied in clastic sedimentology. In order to better constrain the specificities of pyroclastic material, and gain insights into the flow and depositional processes within dilute pyroclastic density currents, the terminal fall velocity was experimentally measured in air and compared to surface roughness and saltation threshold data obtained from wind tunnel experiments as well as with shape parameters. Two types of particles were investigated (scoriaceous material and pumices), as well as different grain sizes (0.125-4mm for scoria and 0.125-16mm for pumices in half phi fractions). The terminal fall velocity corresponds to the velocity for which the drag exerted by air on a particle counteracts its weight, so that acceleration becomes null and the velocity constant. In order to measure the terminal fall velocity, particles were dropped in a closed and large vertical tube (to avoid any perturbation by air movement present in the lab) and the velocity derived from high speed video recorded near the bottom of the tube. By repeating the experiments from different heights, the velocity was seen to increase with increasing drop-height, until reaching a constant value, taken as the terminal fall velocity. The surface roughness is a value that defines how rough a bed of particles is seen by a wind. The saltation threshold corresponds to the near-bed shear-stress necessary for particles to leave the surface and begin to bounce on the bed. Both are derived from wind profiles experimentally measured in a wind tunnel in Aarhus (Denmark; see abstract 2128). Shape parameters were measured with a Camsizer (from Retsch) in Catania (Italy) and the sphericity, symmetry, aspect ratio, and convexity derived. Since the surface roughness, saltation threshold, and terminal fall

  18. Mining for diagnostic information in body surface potential maps: A comparison of feature selection techniques

    Directory of Open Access Journals (Sweden)

    McCullagh Paul J

    2005-09-01

    Full Text Available Abstract Background In body surface potential mapping, increased spatial sampling is used to allow more accurate detection of a cardiac abnormality. Although diagnostically superior to more conventional electrocardiographic techniques, the perceived complexity of the Body Surface Potential Map (BSPM acquisition process has prohibited its acceptance in clinical practice. For this reason there is an interest in striking a compromise between the minimum number of electrocardiographic recording sites required to sample the maximum electrocardiographic information. Methods In the current study, several techniques widely used in the domains of data mining and knowledge discovery have been employed to mine for diagnostic information in 192 lead BSPMs. In particular, the Single Variable Classifier (SVC based filter and Sequential Forward Selection (SFS based wrapper approaches to feature selection have been implemented and evaluated. Using a set of recordings from 116 subjects, the diagnostic ability of subsets of 3, 6, 9, 12, 24 and 32 electrocardiographic recording sites have been evaluated based on their ability to correctly asses the presence or absence of Myocardial Infarction (MI. Results It was observed that the wrapper approach, using sequential forward selection and a 5 nearest neighbour classifier, was capable of choosing a set of 24 recording sites that could correctly classify 82.8% of BSPMs. Although the filter method performed slightly less favourably, the performance was comparable with a classification accuracy of 79.3%. In addition, experiments were conducted to show how (a features chosen using the wrapper approach were specific to the classifier used in the selection model, and (b lead subsets chosen were not necessarily unique. Conclusion It was concluded that both the filter and wrapper approaches adopted were suitable for guiding the choice of recording sites useful for determining the presence of MI. It should be noted however

  19. A comparison of optical and microwave scintillometers with eddy covariance derived surface heat fluxes

    KAUST Repository

    Yee, Mei Sun

    2015-11-01

    Accurate measurements of energy fluxes between land and atmosphere are important for understanding and modeling climatic patterns. Several methods are available to measure heat fluxes, and scintillometers are becoming increasingly popular because of their ability to measure sensible (. H) and latent (. LvE) heat fluxes over large spatial scales. The main motivation of this study was to test the use of different methods and technologies to derive surface heat fluxes.Measurements of H and LvE were carried out with an eddy covariance (EC) system, two different makes of optical large aperture scintillometers (LAS) and two microwave scintillometers (MWS) with different frequencies at a pasture site in a semi-arid environment of New South Wales, Australia. We used the EC measurements as a benchmark. Fluxes derived from the EC system and LAS systems agreed (R2>0.94), whereas the MWS systems measured lower H (bias ~60Wm-2) and larger LvE (bias ~65Wm-2) than EC. When the scintillometers were compared against each other, the two LASs showed good agreement of H (R2=0.98), while MWS with different frequencies and polarizations led to different results. Combination of LAS and MWS measurements (i.e., two wavelength method) resulted in performance that fell in between those estimated using either LAS or MWS alone when compared with the EC system. The cause for discrepancies between surface heat fluxes derived from the EC system and those from the MWS systems and the two-wavelength method are possibly related to inaccurate assignment of the structure parameter of temperature and humidity. Additionally, measurements from MWSs can be associated with two values of the Bowen ratio, thereby leading to uncertainties in the estimation of the fluxes. While only one solution has been considered in this study, when LvE was approximately less than 200Wm-2, the alternate solution may be more accurate. Therefore, for measurements of surface heat fluxes in a semi-arid or dry environment, the

  20. Comparison of surface contamination monitors for in vivo measurement of 131I in the thyroid

    Science.gov (United States)

    Oliveira, S. M.; Dantas, A. L. A.; Dantas, B. M.

    2016-07-01

    The routine handling of radiopharmaceuticals in nuclear medicine represents a significant risk of internal exposure to the staff. The IAEA recommends the implementation of monitoring plans for all workers subject to a risk of exposures above 1 mSv per year. However, in Brazil, such recommendation is practically unfeasible due to the lack of a sufficient number of qualified internal dosimetry services over the country. This work presents an alternative based on a simple and inexpensive methodology aimed to perform in vivo monitoring of 131I in the thyroid using portable surface contamination probes. Results show that all models evaluated in this work present enough sensitivity for the evaluation of accidental intakes.

  1. A comparison of the abrasiveness of six ceramic surfaces and gold.

    Science.gov (United States)

    Jacobi, R; Shillingburg, H T; Duncanson, M G

    1991-09-01

    A type III gold alloy and six different ceramic surfaces were secured in an abrasion machine opposing extracted teeth to determine their relative abrasiveness and resistance to wear. The rankings of restorative materials from least abrasive to most abrasive were: gold alloy, polished; cast ceramic, polished; porcelain, polished; cast ceramic, polished and shaded; porcelain, polished and glazed; cast ceramic, cerammed skin shaded; and cast ceramic, cerammed skin unshaded. The ranking of materials from most wear-resistant to least wear-resistant was: gold alloy, cast ceramic cerammed, cast ceramic cerammed and shaded, porcelain polished, porcelain glazed, cast ceramic polished and shaded, and cast ceramic polished.

  2. Comparison of some corrosion-protective coatings for inner surfaces of tanks

    Energy Technology Data Exchange (ETDEWEB)

    Mityagin, V.A.; Vigant, G.T.; Zakharova, N.N.

    1995-07-01

    Zinc-filled, sprayed-zinc, epoxy, and vinyl chloride coatings were comparatively studied as applied to corrosion protection of inner surfaces and tanks for clarified petroleum products. Tests were carried out by cycles of temperature variation from 60{degrees}C to - 25{degrees}C, on steel plates in vapor, in fuel, and in electrolyte, simulating sub-product water. The coatings KhS-5132, KhS-717 (vinyl chloride) and BEP-68, EP-525, EP-0010 (epoxy) are of the highest protective properties, resistant to steaming and washing with aqueous solutions of synthetic detergents, and are compatible with clarified petroleum products.

  3. Comparison of surface contamination monitors for in vivo measurement of {sup 131}I in thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, S.M.; Dantas, A.L.A.; Dantas, B.M., E-mail: salomao.marques@ymail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The routine handling of radiopharmaceuticals in nuclear medicine represents a significant risk of internal exposure to the staff. The IAEA recommends the implementation of monitoring plans for all workers subject to a risk of exposures above 1 mSv per year. However, in Brazil, such recommendation is practically unfeasible due to the lack of a sufficient number of qualified internal dosimetry services over the country. This work presents an alternative based on a simple and inexpensive methodology aimed to perform in-vivo monitoring of {sup 131}I in thyroid using portable surface contamination probes. All models evaluated showed suitable sensitivity for such application. (author)

  4. 3D simulation of near-fault strong ground motion:comparison between surface rupture fault and buried fault

    Institute of Scientific and Technical Information of China (English)

    Liu Qifang; Yuan Yifan; Jin Xing

    2007-01-01

    In this paper,near-fault strong ground motions caused by a surface rupture fault(SRF)and a buried fault(BF) are numerically simulated and compared by using a time-space-decoupled,explicit finite element method combined with a multi-transmitting formula(MTF) of an artificial boundary.Prior to the comparison,verification of the explicit element method and the MTF is conducted.The comparison results show that the final dislocation of the SRF is larger than the BF for the same stress drop on the fault plane.The maximum final dislocation occurs on the fault upper line for the SRF;however,for the BF,the maximum final dislocation is located on the fault central part.Meanwhile,the PGA,PGV and PGD of long period ground motions(≤1 Hz)generated by the SRF are much higher than those of the BF in the near-fault region.The peak value of the velocity pulse generated by the SRF is also higher than the BF.Furthermore,it is found that in a very narrow region along the fault trace,ground motions caused by the SRF are much higher than by the BF.These results may explain why SRFs almost always cause heavy damage in near-fault regions compared to buried faults.

  5. Glass delamination: a comparison of the inner surface performance of vials and pre-filled syringes.

    Science.gov (United States)

    Zhao, Jianxiu; Lavalley, Virginie; Mangiagalli, Paolo; Wright, Justin M; Bankston, Theresa E

    2014-12-01

    The occurrence of glass delamination is a serious concern for parenteral drug products. Over the past several years, there has been a series of product recalls involving glass delamination in parenteral drugs stored in vials which has led to heightened industry and regulatory scrutiny. In this study, a two-pronged approach was employed to assess the inner surface durability of vials and pre-filled syringes. Non-siliconized syringes were used in order to directly compare glass to glass performance between vials and syringes. The vial and syringe performance was screened with pharmaceutically relevant formulation conditions. The influence of pH, buffer type, ionic strength, and glass type and source was evaluated. In addition, an aggressive but discriminating formulation condition (glutaric acid, pH 11) was used to ascertain the impact of syringe processing. Advanced analytical tools including inductively coupled plasma/mass spectrometry, scanning electron microscopy, atomic force microscopy, and dynamic secondary ion mass spectroscopy showed significant differences in glass performance between vials and syringes. Pre-filled syringes outperform vials for most tests and conditions. The manufacturing conditions for vials lead to glass defects, not found in pre-filled syringes, which result in a less chemically resistant surface. The screening methodology presented in this work can be applied to assess suitability of primary containers for specific drug applications.

  6. A comparison of surface proteins in embryonal carcinoma cells and their differentiated derivatives.

    Science.gov (United States)

    Keil-Dlouha, V; Paulin, D; Bagilet, L K; Keil, B

    1980-03-27

    Surface proteins from five cell lines (three embryonal carcinoma cell lines (F9, PCC4 and PCC3), teratocarcinoma-derived endodermal cells (PYS) and fibroblasts (line 3/A/1-D-3 differentiated from PCC3) were compared by two-dimensional polyacrylamide gel electrophoresis after selective iodination with 125I in the presence of lactoperoxidase. The labeled proteins were solubilized either in Nonidet P40/urea/ampholyte/mercaptoethanol solution or in Nonidet P40 only. In total, about thirty major 125I-labeled surface proteins were identified by their isoelectric point and molecular weight. 14 proteins are present in all five cell types, although their quantity or accessibility for labeling differs between differentiated and undifferentiated cells. Three proteins (200, 160 and 150 kilodaltons) are present in undifferentiated cells only. Two of them (160 and 150 kilodaltons) were solubilized by Nonidet P40/urea/ampholyte/mercaptoethanol, but not by Nonidet P40. One protein (50 kilodaltons) was found in nullipotent F9 cells only. About 14--15 proteins (including fibronectin) were released by Nonidet P40/urea/ampholyte/mercaptoethanol but not by Nonidet P40. They are presumably bound to submembrane or cytoskeleton structures by non-covalent bonds.

  7. Comparison of several surfaces for use as a MWIR BRDF standard

    Science.gov (United States)

    Balling, Bradley L.; Marciniak, Michael A.

    2009-08-01

    The Bidirectional Reflectance Distribution Function (BRDF) has a well defined and studied diffuse measurement standard in the ultraviolet, visible and near infrared (NIR), Spectralon®. It is predictable, stable, repeatable, and has low surface variation because it is a bulk scatterer. In the mid-wave IR (MWIR) and long-wave IR (LWIR), there is not such a well-defined standard. There are well-defined directional hemispherical reflectance (DHR) standards, but the process of integrating BRDF measurements into DHR for the purpose of calibration is problematic at best. Direct BRDF measurement standards are needed. This study systematically investigates the BRDF and its variation for six potential MWIR diffuse BRDF standards. The currently accepted reflectance standard in the MWIR, Infragold®, is compared against two alternative gold-electroplated arc-sprayed aluminum samples, a silver-painted arc-sprayed aluminum sample, a black-paint sample, Spectralon®, and a novel a laser beam diffuser that has been gold coated. Diffuseness is compared by fitting the data to BRDF models, and repeatability is measured by using the standard deviation and percent difference from the mean calculated from multiple BRDF measurements across the surface of the samples.

  8. A Comparison of Land Surface Model Soil Hydraulic Properties Estimated by Inverse Modeling and Pedotransfer Functions

    Science.gov (United States)

    Gutmann, Ethan D.; Small, Eric E.

    2007-01-01

    Soil hydraulic properties (SHPs) regulate the movement of water in the soil. This in turn plays an important role in the water and energy cycles at the land surface. At present, SHPS are commonly defined by a simple pedotransfer function from soil texture class, but SHPs vary more within a texture class than between classes. To examine the impact of using soil texture class to predict SHPS, we run the Noah land surface model for a wide variety of measured SHPs. We find that across a range of vegetation cover (5 - 80% cover) and climates (250 - 900 mm mean annual precipitation), soil texture class only explains 5% of the variance expected from the real distribution of SHPs. We then show that modifying SHPs can drastically improve model performance. We compare two methods of estimating SHPs: (1) inverse method, and (2) soil texture class. Compared to texture class, inverse modeling reduces errors between measured and modeled latent heat flux from 88 to 28 w/m(exp 2). Additionally we find that with increasing vegetation cover the importance of SHPs decreases and that the van Genuchten m parameter becomes less important, while the saturated conductivity becomes more important.

  9. Parametric surface modeling and registration for comparison of manual and automated segmentation of the hippocampus.

    Science.gov (United States)

    Shen, Li; Firpi, Hiram A; Saykin, Andrew J; West, John D

    2009-06-01

    Accurate and efficient segmentation of the hippocampus from brain images is a challenging issue. Although experienced anatomic tracers can be reliable, manual segmentation is a time consuming process and may not be feasible for large-scale neuroimaging studies. In this article, we compare an automated method, FreeSurfer (V4), with a published manual protocol on the determination of hippocampal boundaries from magnetic resonance imaging scans, using data from an existing mild cognitive impairment/Alzheimer's disease cohort. To perform the comparison, we develop an enhanced spherical harmonic processing framework to model and register these hippocampal traces. The framework treats the two hippocampi as a single geometric configuration and extracts the positional, orientation, and shape variables in a multiobject setting. We apply this framework to register manual tracing and FreeSurfer results together and the two methods show stronger agreement on position and orientation than shape measures. Work is in progress to examine a refined FreeSurfer segmentation strategy and an improved agreement on shape features is expected.

  10. Waste Transfer Stations

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund

    2011-01-01

    tion and transport is usually the most costly part of any waste management system; and when waste is transported over a considerable distance or for a long time, transferring the waste from the collection vehicles to more efficient transportation may be economically beneficial. This involves...... a transfer station where the transfer takes place. These stations may also be accessible by private people, offering flexibility to the waste system, including facilities for bulky waste, household hazardous waste and recyclables. Waste transfer may also take place on the collection route from small...... describes the main features of waste transfer stations, including some considerations about the economical aspects on when transfer is advisable....

  11. Space station operations management

    Science.gov (United States)

    Cannon, Kathleen V.

    1989-01-01

    Space Station Freedom operations management concepts must be responsive to the unique challenges presented by the permanently manned international laboratory. Space Station Freedom will be assembled over a three year period where the operational environment will change as significant capability plateaus are reached. First Element Launch, Man-Tended Capability, and Permanent Manned Capability, represent milestones in operational capability that is increasing toward mature operations capability. Operations management concepts are being developed to accomodate the varying operational capabilities during assembly, as well as the mature operational environment. This paper describes operations management concepts designed to accomodate the uniqueness of Space Station Freedoom, utilizing tools and processes that seek to control operations costs.

  12. Final Comparison of TM and MSS Data for Surface Mine Assessment in Logan County, West Virginia

    Science.gov (United States)

    Witt, R. G.; Blodget, H. W.; Marcell, R. M.

    1984-01-01

    A variety of classifications during both raw and transformed MSS and TM data sets from 4 September 1982 were performed for the Logan County, West Virginia study area. The object was to compare the utility of TM and MSS data for delineating small, irregular ground features, particularly surface mines, and also to test data reduction/transformation techniques (band selection, canonical analysis, and principal components) in relation to a traditional means of unsupervised classification. Statistical results demonstrate that, on the average, the TM classifications yielded an overall .53 factor of improvement relative to the MSS classifications. When the accuracies for only three minor (in terms of areal extent) land use categories are examined, the factor of improvement for TM over MSS increases to 1.48; i.e., the TM is nearly one and one-half times better than the MSS for delineating small and irregular ground features such as contour strip mines.

  13. Technical Note: Comparison of storage strategies of sea surface microlayer samples

    Directory of Open Access Journals (Sweden)

    K. Schneider-Zapp

    2013-02-01

    Full Text Available The sea surface microlayer (SML is an important biogeochemical system whose physico-chemical analysis often necessitates some degree of sample storage. However, many SML components degrade with time so the development of optimal storage protocols is paramount. Using freshwater and saline SML samples from a river-estuary, we interrogated temporal changes in surfactant activity (SA and the absorbance and fluorescence of chromophoric dissolved organic matter (CDOM over four weeks, following selected sample treatment and storage protocols. Some variability in the effectiveness of individual protocols most likely reflects sample provenance. None of the various protocols examined performed any better than dark storage at 4 °C without pre-treatment. We thus recommend this as the optimal strategy, coupled with minimal storage times as far as practicable. Future studies of SML properties should validate their chosen storage protocols independently.

  14. Technical Note: Comparison of storage strategies of sea surface microlayer samples

    Directory of Open Access Journals (Sweden)

    K. Schneider-Zapp

    2013-07-01

    Full Text Available The sea surface microlayer (SML is an important biogeochemical system whose physico-chemical analysis often necessitates some degree of sample storage. However, many SML components degrade with time so the development of optimal storage protocols is paramount. We here briefly review some commonly used treatment and storage protocols. Using freshwater and saline SML samples from a river estuary, we investigated temporal changes in surfactant activity (SA and the absorbance and fluorescence of chromophoric dissolved organic matter (CDOM over four weeks, following selected sample treatment and storage protocols. Some variability in the effectiveness of individual protocols most likely reflects sample provenance. None of the various protocols examined performed any better than dark storage at 4 °C without pre-treatment. We therefore recommend storing samples refrigerated in the dark.

  15. Comparison of iterative solvers for electromagnetic analysis of plasmonic nanostructures using multiple surface integral equation formulations

    CERN Document Server

    Gomez-Sousa, Hipolito; Martinez-Lorenzo, Jose Angel

    2015-01-01

    The electromagnetic behavior of plasmonic structures can be predicted after discretizing and solving a linear system of equations, derived from a continuous surface integral equation (SIE) and the appropriate boundary conditions, using a method of moments (MoM) methodology. In realistic large-scale optical problems, a direct inversion of the SIE-MoM matrix cannot be performed due to its large size, and an iterative solver must be used instead. This paper investigates the performance of four iterative solvers (GMRES, TFQMR, CGS, and BICGSTAB) for five different SIE-MoM formulations (PMCHWT, JMCFIE, CTF, CNF, and MNMF). Moreover, under this plasmonic context, a set of suggested guidelines are provided to choose a suitable SIE formulation and iterative solver depending on the desired simulation error and available runtime resources.

  16. Comparison of finite element and transfer matrix methods for numerical investigation of surface plasmon waveguides

    Science.gov (United States)

    Haddouche, Issam; Cherbi, Lynda

    2017-01-01

    In this paper, we investigate Surface Plasmon Polaritons (SPPs) in the visible regime at a metal/dielectric interface within two different waveguide structures, the first is a Photonic Crystal Fiber where the Full Vector Finite Element Method (FVFEM) is used and the second is a slab waveguide where the transfer matrix method (TMM) is used. Knowing the diversities between the two methods in terms of speed, simplicity, and scope of application, computation is implemented with respect to wavelength and metal layer thickness in order to analyze and compare the performances of the two methods. Simulation results show that the TMM can be a good approximation for the FVFEM and that SPPs behave more like modes propagating in a semi infinite metal/dielectric structure as metal thickness increases from about 150 nm.

  17. A Comparison of the Reproduction of Surface Detail of Three Tissues Conditioning Materials over Time

    Directory of Open Access Journals (Sweden)

    Nili M.

    2012-09-01

    Full Text Available Statement of Problem: Although the basic use of tissue conditioners is to treat inflamed mucosa, they are also employed as functional impression materials. No information was obtained on the reproduction of surface detail of these materials over time.Purpose: The purpose of this study was to evaluate changes in the surface quality of three tissue conditioners after being immersed in water for a period of time.Materials and Method: Detail reproduction was determined by using from a ruled test block the same it was specified in ISO Specification 4823. Three tissue conditioners (GC, Acrosoft, and Visco-gel were evaluated. Samples were made by pouring freshly mixed materials into a ruled test block. The samples were then stored in distilled water for either of the followings periods of time: 0 hour, 24 hours, 3 days, 7 days, 14 days. Subsequently, the dental stone was mixed with distilled water and poured on each sample and allowed to remain for 60 minutes. Then, 25 specimens were prepared. The detail reproduction was determined based on what is specified in ISO Specification 4823. The samples were examined under a stereo-microscope with low-angle illumination. The data was analyzed through running Kruskal-Wallis Test and Mann-Whitney Test.Results: The three materials had minimum standard of detail reproduction. The detail reproduction were more significantly influenced by the time period of immersion in water ( p <0.0005 than the type of the material. The best detail reproduction was pertained to Visco-gel not immersed in water. Acrosoft was less influenced by the time period of immersion in water than the two other types.Conclusion: The detail reproduction may be attributed to chemical composition. The type of material and immersion time had a significant effect, while the effect of the type was less significant. The best time for making functional impressions was ranges from 0 to 24 hours.

  18. Comparison of prognostic and diagnostic surface flux modeling approaches over the Nile River basin

    Science.gov (United States)

    Yilmaz, M. Tugrul; Anderson, Martha C.; Zaitchik, Ben; Hain, Chris R.; Crow, Wade T.; Ozdogan, Mutlu; Chun, Jong Ahn; Evans, Jason

    2014-01-01

    Regional evapotranspiration (ET) can be estimated using diagnostic remote sensing models, generally based on principles of energy balance closure, or with spatially distributed prognostic models that simultaneously balance both energy and water budgets over landscapes using predictive equations for land surface temperature and moisture states. Each modeling approach has complementary advantages and disadvantages, and in combination they can be used to obtain more accurate ET estimates over a variety of land and climate conditions, particularly for areas with limited ground truth data. In this study, energy and water flux estimates from diagnostic Atmosphere-Land Exchange (ALEXI) and prognostic Noah land surface models are compared over the Nile River basin between 2007 and 2011. A second remote sensing data set, generated with Penman-Monteith approach as implemented in the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD16 ET product, is also included as a comparative technique. In general, spatial and temporal distributions of flux estimates from ALEXI and Noah are similar in regions where the climate is temperate and local rainfall is the primary source of water available for ET. However, the diagnostic ALEXI model is better able to retrieve ET signals not directly coupled with the local precipitation rates, for example, over irrigated agricultural areas or regions influenced by shallow water tables. These hydrologic features are not well represented by either Noah or MOD16. Evaluation of consistency between diagnostic and prognostic model estimates can provide useful information about relative product skill, particularly over regions where ground data are limited or nonexistent as in the Nile basin.

  19. Comparison of two tooth-saving preparation techniques for one-surface cavities.

    Science.gov (United States)

    Rahimtoola, Salim; van Amerongen, Evert

    2002-01-01

    The atraumatic restorative treatment technique (ART) is based on removing infected tooth material using only hand instruments and filling the subsequently cleaned cavity with adhesive material such as glass ionomer. As its name suggests, the ART technique should be atraumatic during treatment, as well as for the tooth itself as for the patient. It was primarily developed for treating people living in underserved areas of the world where resources and facilities such as electricity and trained manpower are limited. Many studies have evaluated the ART technique and the results have supported its application. However, a very limited number of studies have compared ART with more conventional techniques. For that reason, a study was conducted in Pakistan, to compare the ART technique with another more conventional treatment technique. The results of this study show that the preparations with hand instruments resulted in smaller sized cavities and therefore may be less traumatic to the tooth. It was also associated with less pain reactions compared to the more conventional technique. Although preparations with hand instruments required more time, this did not seem to affect the survival of restorations. The survival of glass ionomer cement restorations made with hand instruments was comparable with single surface amalgam restorations made with a more conventional technique. Recurrent caries was not associated with any glass ionomer cement restorations made with hand instruments. The retention rate of glass ionomer sealants was low, however one dentist had a sealant retention rate of 81.5 percent that suggests that this procedure can be performed satisfactorily in conjunction with a glass ionomer cement restoration. Operator variances did seem to affect the restorations. Survival of glass ionomer restorations made with both hand and rotary instruments varied for different operators. Similarly, the retention of fissure sealant also varied amongst operators. Operator

  20. Muscular adaptations to depth jump plyometric training: Comparison of sand vs. land surface.

    Science.gov (United States)

    Arazi, Hamid; Mohammadi, Mahdi; Asadi, Abbas

    2014-09-01

    The purpose of this study was to compare the effects of plyometric training on sand vs. land surface on muscular performance adaptations in men. Fourteen healthy men were randomly assigned to two training groups: a) Sand Depth Jump (SDJ; N = 7) and b) Land Depth Jump (LDJ; N = 7). Training was performed for 6 weeks and consisted of 5 × 20 repetitions of DJ training on 20-cm dry sand or 3-cm hard court surface twice weekly. Vertical Jump Test (VJT), Standing Long Jump Test (SLJT), 20-m and 40-m sprint, T-test (TT) and one repetition maximum leg press (1RMLP) were performed before and after training. Significant improvements in VJT [4 (ES = 0.63) vs. 5.4 (ES = 0.85) cm], SLJT [8.3 (ES = 0.3) vs. 12.7 (ES = 0.57) cm], and 1RMLP [23.5 (ES = 0.56) vs. 15.3 (ES = 0.49) kg] were seen for both the groups. Likewise, significant decreases were observed for both SDJ and LDJ groups in 20-m [0.3 (ES = 0.72) vs. 0.4 (ES = 1.98) s] and 40-m sprint times [0.2 (ES = 0.4) vs. 0.5 (ES = 0.71) s], and TT [0.5 (ES = 0.62) vs. 0.9 (ES = 0.57) s]. With regard to ES, it can be recommended that athletes used LDJ training for enhancing sprint and jump and SDJ training for improving agility and strength.

  1. Comparison of sampling methods to recover germinated Bacillus anthracis and Bacillus thuringiensis endospores from surface coupons.

    Science.gov (United States)

    Mott, T M; Shoe, J L; Hunter, M; Woodson, A M; Fritts, K A; Klimko, C P; Quirk, A V; Welkos, S L; Cote, C K

    2017-05-01

    In an attempt to devise decontamination methods that are both effective and minimally detrimental to the environment, we evaluated germination induction as an enhancement to strategies for Bacillus anthracis spore decontamination. To determine an optimal method for the recovery of germinating spores from different matrices, it was critical to ensure that the sampling procedures did not negatively impact the viability of the germinating spores possibly confounding the results and downstream analyses of field trial data. Therefore, the two main objectives of this study were the following: (i) development of an effective processing protocol capable of recovering the maximum number of viable germinating or germinated spores from different surface materials; and (ii) using a model system of spore contamination, employ this protocol to evaluate the potential applicability of germination induction to wide-area decontamination of B. anthracis spores. We examined parameters affecting the sampling efficiencies of B. anthracis and the surrogate species Bacillus thuringiensis on nonporous and porous materials. The most efficient extraction from all matrices was observed using PBS with 0·01% Tween 80 extraction buffer. The addition of a sonication and/or extended vortex treatment did not yield significant increases in spore or germinated spore recovery. Our data demonstrate that previous germination-induction experiments performed in suspension can be reproduced when Bacillus spores are deposited onto reference surfaces materials. Our proof of concept experiment illustrated that a germination pretreatment step significantly improves conventional secondary decontamination strategies and remediation plans. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  2. Signal Station Inspection Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Handwritten reports resulting from detailed inspections of US Army Signal Service Stations, 1871-1889. Features reported included instrument exposure and condition,...

  3. FEMA DFIRM Station Start

    Data.gov (United States)

    Minnesota Department of Natural Resources — This table contains information about station starting locations. These locations indicate the reference point that was used as the origin for distance measurements...

  4. "Central Station" Londonis

    Index Scriptorium Estoniae

    2000-01-01

    Londoni galeriis Milch seitsme läti, leedu ja eesti kunstniku projekt "Central Station". Kuraatorid Lisa Panting, Sally Tallant. Eestist osalevad Hanno Soans (Catarina Campinoga koostöös valminud video), Kiwa, Kai Kaljo

  5. Realtime USGS Streamflow Stations

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Approximately 5,000 of the 6,900 U.S. Geological Survey sampling stations are equipped with telemetry to transmit data on streamflow, temperature, and other...

  6. "Central Station" Londonis

    Index Scriptorium Estoniae

    2000-01-01

    Londoni galeriis Milch seitsme läti, leedu ja eesti kunstniku projekt "Central Station". Kuraatorid Lisa Panting, Sally Tallant. Eestist osalevad Hanno Soans (Catarina Campinoga koostöös valminud video), Kiwa, Kai Kaljo

  7. Master Station History Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Standard/Legacy MSHR, formally identified as the DSI-9767 dataset, is the legacy dataset/report sorted by NCDC Station ID and period of record. This...

  8. Materials Test Station

    Data.gov (United States)

    Federal Laboratory Consortium — When completed, the Materials Test Station at the Los Alamos Neutron Science Center will meet mission need. MTS will provide the only fast-reactor-like irradiation...

  9. Natural Weathering Exposure Station

    Data.gov (United States)

    Federal Laboratory Consortium — The Corps of Engineers' Treat Island Natural Weathering Exposure Station is a long-term natural weathering facility used to study concrete durability. Located on the...

  10. Station Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The following plan is the result of a recent initiative in Region 5 to produce general management guidance based on stated objectives for individual field stations....

  11. Maine Field Station

    Data.gov (United States)

    Federal Laboratory Consortium — In 2000 NOAA's National Marine Fisheries Service established the Maine Field Station in Orono, ME to have more direct involvement in the conservation of the living...

  12. Electrostatic pickup station

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    Electrostatic pickup station, with 4 interleaved electrodes, to measure beam position in the horizontal and vertical plane. This type is used in the transfer lines leaving the PS (TT2, TT70, TTL2). See also 7904075.

  13. USRCRN Station Information

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Documentation of United States Regional Climate Reference Network (USRCRN) installations in 2009. Installations documented are for USRCRN pilot project stations in...

  14. Space Station Food System

    Science.gov (United States)

    Thurmond, Beverly A.; Gillan, Douglas J.; Perchonok, Michele G.; Marcus, Beth A.; Bourland, Charles T.

    1986-01-01

    A team of engineers and food scientists from NASA, the aerospace industry, food companies, and academia are defining the Space Station Food System. The team identified the system requirements based on an analysis of past and current space food systems, food systems from isolated environment communities that resemble Space Station, and the projected Space Station parameters. The team is resolving conflicts among requirements through the use of trade-off analyses. The requirements will give rise to a set of specifications which, in turn, will be used to produce concepts. Concept verification will include testing of prototypes, both in 1-g and microgravity. The end-item specification provides an overall guide for assembling a functional food system for Space Station.

  15. Mukilteo Research Station

    Data.gov (United States)

    Federal Laboratory Consortium — Research at the Mukilteo Research Station focuses on understanding the life cycle of marine species and the impacts of ecosystem stressors on anadromous and marine...

  16. TV Analog Station Transmitters

    Data.gov (United States)

    Department of Homeland Security — This file is an extract from the Consolidated Database System (CDBS) licensed by the Media Bureau. It consists of Analog Television Stations (see Rule Part47 CFR...

  17. Public Transit Stations

    Data.gov (United States)

    Department of Homeland Security — fixed rail transit stations within the Continental United States, Alaska, Hawaii, the District of Columbia, and Puerto Rico. The modes of transit that are serviced...

  18. Routes and Stations

    Data.gov (United States)

    Department of Homeland Security — he Routes_Stations table is composed of fixed rail transit systems within the Continental United States, Alaska, Hawaii, the District of Columbia, and Puerto Rico....

  19. Active Marine Station Metadata

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Active Marine Station Metadata is a daily metadata report for active marine bouy and C-MAN (Coastal Marine Automated Network) platforms from the National Data...

  20. Enhanced Master Station History Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Enhanced Master Station History Report (EMSHR) is a compiled list of basic, historical information for every station in the station history database, beginning...

  1. Leadership at Antarctic Stations.

    Science.gov (United States)

    1987-03-01

    Claseification 6. No. Pegees LEADERSHIP AT ANTARTIC STATIONS hxIs i4 5, C =r~eta(C), 17 Rfs~W (R, Udusiied U)J 7. No Refs 8. Author(s) Edocumesnt I...whether there is a "best" approach to leadership at an Antartic Station and what leadership style may have the most to offer. 3~~ __ ___ Tipesis to be

  2. LAERTIS, a multidisciplinary station

    Science.gov (United States)

    Aggouras, G.; Anassontzis, E. G.; Ball, A. E.; Chinowsky, W.; Fahrun, E.; Grammatikakis, G.; Green, C.; Grieder, P.; Katrivanos, P.; Koske, P.; Markopoulos, E.; Minkowsky, P.; Nygren, D.; Papageorgiou, K.; Przybylski, G.; Resvanis, L. K.; Siotis, I.; Sopher, J.; Tsagli, V.; Zhukov, V. A.

    2006-11-01

    LAERTIS, designed to collect environmental data from the deep-sea, is operated since 1999 and has been deployed several time at 4000 m depth at the NESTOR site. Power and data were transferred through a 30-km electro-optical cable to the Shore Station. In this report, we describe briefly the LAERTIS instrumentation and present typical data that were collected successfully during those deployment demonstrating the importance of a deep-sea station permanently connected to shore.

  3. Comparisons of particles thermal behavior between Fe-base alloy and boron carbide during plasma transferred-arc powder surfacing

    Institute of Scientific and Technical Information of China (English)

    王惜宝

    2003-01-01

    Comparisons of particle's thermal behavior between Fe-base alloy and boron carbide in plasma transferred-arc (PTA) space was made based on theoretical evaluation results in this article. It was found that most of the Fe base particles would be fully melted while they transporting through the central plasma field with 200 A surfacing currents. And the particles with a diameter less than 0.5×10-4 m might be fully evaporated. However, for the boron carbide (B4C) particles, only the one with a diameter less than 0.5×10-4 m could be melted in the same PTA space. Most of B4C particles are only preheated at its solid state when they were fed through the central field of PTA plasma when the surfacing current is equal to or less than 200 A. When the arc current was smaller than100 A, only the particles smaller than 0.5×10-4 m could be melted in the PTA space for the Fe-base alloy. Almost none of the discussed B4C particles could be melted in the 100 A PTA space.

  4. Comparison of protocols for walking and running kinematics based on skin surface markers and rigid clusters of markers.

    Science.gov (United States)

    Miana, A N; Prudêncio, M V; Barros, R M L

    2009-11-01

    The purpose of this study was to compare the two main types of marker sets for human body representation based on rigid clusters of markers and skin surface markers for measuring kinematics during walking and running. Velocity, body segment, and joint angle were considered in the comparison of both protocols. Six male athletes were studied during treadmill gait at 1.4 and 5.5 m/s and recorded with 8 high speed video cameras. The subjects used simultaneously both protocols in the same walking and running cycles, in order to compare the variability in the determination of the joint centers' positions and the joint angles calculated from each protocol. The three-way ANOVA results showed that the variability of the inter-markers distance in the skin surface protocol was higher than that in the rigid clusters of markers, as reported in the literature. However, no statistical differences between the protocols were found in the variability of the determination of the joint centers' positions. Therefore no advantage was verified to rigid cluster protocols even for the upper body segments. Another conclusion is that increases in velocity produced increases in variability of the joint centers' distances and increases in the maximum differences between the joint angles.

  5. Surface Charge Measurement of SonoVue, Definity and Optison: A Comparison of Laser Doppler Electrophoresis and Micro-Electrophoresis.

    Science.gov (United States)

    Ja'afar, Fairuzeta; Leow, Chee Hau; Garbin, Valeria; Sennoga, Charles A; Tang, Meng-Xing; Seddon, John M

    2015-11-01

    Microbubble (MB) contrast-enhanced ultrasonography is a promising tool for targeted molecular imaging. It is important to determine the MB surface charge accurately as it affects the MB interactions with cell membranes. In this article, we report the surface charge measurement of SonoVue, Definity and Optison. We compare the performance of the widely used laser Doppler electrophoresis with an in-house micro-electrophoresis system. By optically tracking MB electrophoretic velocity in a microchannel, we determined the zeta potentials of MB samples. Using micro-electrophoresis, we obtained zeta potential values for SonoVue, Definity and Optison of -28.3, -4.2 and -9.5 mV, with relative standard deviations of 5%, 48% and 8%, respectively. In comparison, laser Doppler electrophoresis gave -8.7, +0.7 and +15.8 mV with relative standard deviations of 330%, 29,000% and 130%, respectively. We found that the reliability of laser Doppler electrophoresis is compromised by MB buoyancy. Micro-electrophoresis determined zeta potential values with a 10-fold improvement in relative standard deviation.

  6. Comparison of several databases of downward solar daily irradiation data at ocean surface with PIRATA measurements

    Science.gov (United States)

    Trolliet, Mélodie; Wald, Lucien

    2017-04-01

    The solar radiation impinging at sea surface is an essential variable in climate system. There are several means to assess the daily irradiation at surface, such as pyranometers aboard ship or on buoys, meteorological re-analyses and satellite-derived databases. Among the latter, assessments made from the series of geostationary Meteosat satellites offer synoptic views of the tropical and equatorial Atlantic Ocean every 15 min with a spatial resolution of approximately 5 km. Such Meteosat-derived databases are fairly recent and the quality of the estimates of the daily irradiation must be established. Efforts have been made for the land masses and must be repeated for the Atlantic Ocean. The Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) network of moorings in the Tropical Atlantic Ocean is considered as a reference for oceanographic data. It consists in 17 long-term Autonomous Temperature Line Acquisition System (ATLAS) buoys equipped with sensors to measure near-surface meteorological and subsurface oceanic parameters, including downward solar irradiation. Corrected downward solar daily irradiation from PIRATA were downloaded from the NOAA web site and were compared to several databases: CAMS RAD, HelioClim-1, HelioClim-3 v4 and HelioClim-3 v5. CAMS-RAD, the CAMS radiation service, combines products of the Copernicus Atmosphere Monitoring Service (CAMS) on gaseous content and aerosols in the atmosphere together with cloud optical properties deduced every 15 min from Meteosat imagery to supply estimates of the solar irradiation. Part of this service is the McClear clear sky model that provides estimates of the solar irradiation that should be observed in cloud-free conditions. The second and third databases are HelioClim-1 and HelioClim-3 v4 that are derived from Meteosat images using the Heliosat-2 method and the ESRA clear sky model, based on the Linke turbidity factor. HelioClim-3 v5 is the fourth database and differs from v4 by the

  7. The Princess Elisabeth Station

    Science.gov (United States)

    Berte, Johan

    2012-01-01

    Aware of the increasing impact of human activities on the Earth system, Belgian Science Policy Office (Belspo) launched in 1997 a research programme in support of a sustainable development policy. This umbrella programme included the Belgian Scientific Programme on Antarctic Research. The International Polar Foundation, an organization led by the civil engineer and explorer Alain Hubert, was commissioned by the Belgian Federal government in 2004 to design, construct and operate a new Belgian Antarctic Research Station as an element under this umbrella programme. The station was to be designed as a central location for investigating the characteristic sequence of Antarctic geographical regions (polynia, coast, ice shelf, ice sheet, marginal mountain area and dry valleys, inland plateau) within a radius of 200 kilometers (approx.124 miles) of a selected site. The station was also to be designed as "state of the art" with respect to sustainable development, energy consumption, and waste disposal, with a minimum lifetime of 25 years. The goal of the project was to build a station and enable science. So first we needed some basic requirements, which I have listed here; plus we had to finance the station ourselves. Our most important requirement was that we decided to make it a zero emissions station. This was both a philosophical choice as we thought it more consistent with Antarctic Treaty obligations and it was also a logistical advantage. If you are using renewable energy sources, you do not have to bring in all the fuel.

  8. Comparison of a novel surface laser scanning anthropometric technique to traditional methods for facial parameter measurements.

    Science.gov (United States)

    Joe, Paula S; Ito, Yasushi; Shih, Alan M; Oestenstad, Riedar K; Lungu, Claudiu T

    2012-01-01

    This study was designed to determine if three-dimensional (3D) laser scanning techniques could be used to collect accurate anthropometric measurements, compared with traditional methods. The use of an alternative 3D method would allow for quick collection of data that could be used to change the parameters used for facepiece design, improving fit and protection for a wider variety of faces. In our study, 10 facial dimensions were collected using both the traditional calipers and tape method and a Konica-Minolta Vivid9i laser scanner. Scans were combined using RapidForm XOR software to create a single complete facial geometry of the subject as a triangulated surface with an associated texture image from which to obtain measurements. A paired t-test was performed on subject means in each measurement by method. Nine subjects were used in this study: five males (one African-American and four Caucasian females) and four females displaying a range of facial dimensions. Five measurements showed significant differences (pLaser scanning measurements showed high precision and accuracy when compared with traditional methods. Significant differences found can be very small changes in measurements and are unlikely to present a practical difference. The laser scanning technique demonstrated reliable and quick anthropometric data collection for use in future projects in redesigning respirators.

  9. Comparison of kinetic models for atom recombination on high-temperature reusable surface insulation

    Science.gov (United States)

    Willey, Ronald J.

    1993-01-01

    Five kinetic models are compared for their ability to predict recombination coefficients for oxygen and nitrogen atoms over high-temperature reusable surface insulation (HRSI). Four of the models are derived using Rideal-Eley or Langmuir-Hinshelwood catalytic mechanisms to describe the reaction sequence. The fifth model is an empirical expression that offers certain features unattainable through mechanistic description. The results showed that a four-parameter model, with temperature as the only variable, works best with data currently available. The model describes recombination coefficients for oxygen and nitrogen atoms for temperatures from 300 to 1800 K. Kinetic models, with atom concentrations, demonstrate the influence of atom concentration on recombination coefficients. These models can be used for the prediction of heating rates due to catalytic recombination during re-entry or aerobraking maneuvers. The work further demonstrates a requirement for more recombination experiments in the temperature ranges of 300-1000 K, and 1500-1850 K, with deliberate concentration variation to verify model requirements.

  10. Comparison of Oxidative Stresses Mediated by Different Crystalline Forms and Surface Modification of Titanium Dioxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Karim Samy El-Said

    2015-01-01

    Full Text Available Titanium dioxide nanoparticles (TiO2 NPs are manufactured worldwide for use in a wide range of applications. There are two common crystalline forms of TiO2 anatase and rutile with different physical and chemical characteristics. We previously demonstrated that an increased DNA damage response is mediated by anatase crystalline form compared to rutile. In the present study, we conjugated TiO2 NPs with polyethylene glycol (PEG in order to reduce the genotoxicity and we evaluated some oxidative stress parameters to obtain information on the cellular mechanisms of DNA damage that operate in response to TiO2 NPs different crystalline forms exposure in hepatocarcinoma cell lines (HepG2. Our results indicated a significant increase in oxidative stress mediated by the anatase form of TiO2 NPs compared to rutile form. On the other hand, PEG modified TiO2 NPs showed a significant decrease in oxidative stress as compared to TiO2 NPs. These data suggested that the genotoxic potential of TiO2 NPs varies with crystalline form and surface modification.

  11. Comparison of different cloud types from surface and satellite cloud classification products over China

    Science.gov (United States)

    Wang, Minyan; Zeng, Le; Wang, Shengjie; Gu, Junxia; Yang, Runzhi

    2016-04-01

    Different cloud types usually have different cloud dynamic process and micro-physical characteristics, and the relative cloud radiation forcing effects vary much. In recent years, the focus of cloud classification is the algorithm development, as well as the analysis on total cloud amount, high/middle/low cloud amount. While, research on the different cloud types (like cirrus, stratus, and cumulonimbus) is not enough. In this research, we use multi-resources cloud classification products including FY-2, Cloudsat and surface observation to obtain the temporal-spatial distribution characteristics and evolvement of different cloud types in different regions of China, analyze the quantitative difference of multi-source products and the reasons. According to the temporal and spatial scales of cloud, and temporal-spatial representation of cloud classification products based on CloudSat, etc, the scaling is necessary to explore in temporal-spatial matching/validation research. This research have important scientific significances on understanding the regional characteristics of different cloud types in China, improving the remote sensing retrieve algorithms on cloud classification, temporal-spatial matching/validation techniques of satellite data, and cloud vertical structure parameterized methods in numerical models.

  12. Comparison between MODIS and AIRS/AMSU satellite-derived surface skin temperatures

    Directory of Open Access Journals (Sweden)

    Y.-R. Lee

    2012-10-01

    Full Text Available Surface skin temperatures of the Version 5 Level 3 products of MODIS and AIRS/AMSU have been compared in terms of monthly anomaly trends and climatology over the globe during the period from September 2002 to August 2011. The MODIS temperatures in the 50° N–50° S region tend to systematically be ~1.7 K colder over land and ~0.5 K warmer over ocean than the AIRS/AMSU temperatures. Over high latitude ocean the MODIS values are ~5.5 K warmer than the AIRS/AMSU. The discrepancies between the annual averages of the two sensors are as much as ~12 K in the sea ice regions. Both MODIS and AIRS/AMSU show cooling trends from −0.05 ± 0.06 to −0.14 ± 0.07 K (9 yr−1 over the globe, but warming trends (0.02 ± 0.12–0.15 ± 0.19 K (9 yr−1 in the high latitude regions. The disagreement between the two sensors results mainly from the differences in ice/snow emissivity between MODIS infrared and AMSU microwave, and also in their observational local times.

  13. Comparison of unsteady pressure fields on turrets with different surface features using pressure-sensitive paint

    Science.gov (United States)

    Gordeyev, Stanislav; De Lucca, Nicholas; Jumper, Eric J.; Hird, Kyle; Juliano, Thomas J.; Gregory, James W.; Thordahl, James; Wittich, Donald J.

    2014-01-01

    Spatially temporally resolved unsteady pressure fields on a surface of a hemisphere-on-cylinder turret with either a flat or a conformal window with realistic features such as gaps and "smile" cutouts were characterized using fast-response pressure-sensitive paint at M = 0.33 for several window viewing angles. Various statistical properties of pressure fields were computed, and geometry effects on the unsteady pressure fields were analyzed and discussed. Proper orthogonal decomposition was also used to extract dominant pressure modes and corresponding temporal coefficients and to analyze and compare instantaneous pressure structures for different turret geometric features and the window viewing angles. An unsteady separation off the turret and a recirculation region downstream of the turret were identified as dominant sources of the unsteady pressure. It was found that while all geometric features affected the unsteady pressure field, the "smiles," positioned spanwise-symmetrically on both sides of the turret, were the leading cause of these changes, followed by the looking forward flat window. The gaps, the side- and the back-looking flat window introduced only small local changes.

  14. Comparison of aerosol volume size distributions between column and surface measurements downwind of Seoul, Korea

    Science.gov (United States)

    Park, J. S.; Choi, Y.; Ghim, Y. S.

    2015-12-01

    The aerosol volume size distribution is one of the most important parameters in retrieving aerosol optical properties and studying radiative forcing. The column-integrated aerosol volume size distribution for AERONET was obtained from inversion product level 1.5 (22 bins between 0.1 and 30 μm in diameter) from the measurements of CIMEL sunphotometer (CE-318); that for SKYNET was obtained using skyrad.pack V5 (20 bins, 0.02-33 μm) from the measurements of PREDE skyradiometer (POM-02). The aerosol volume size distribution at the surface was measured using a wide range aerosol spectrometer system consisting of a scanning mobility particle scanner (Grimm, Model 5.419; 89 bins, 0.005-0.35 μm) and an optical particle counter (Grimm, Model 1.109; 31 bins, 0.27-34 μm). The measurement was conducted in Yongin, downwind of Seoul, Korea, from April 30 to June 27, 2015. The measurement site is located on the rooftop of a five-story building on the hill (37.34°N, 127.27°E, 167 m above sea level) in the global campus of Hankuk University of Foreign Studies. To investigate the discrepancy in effective diameter and fine mode volume fraction, we compared the volume size distributions when the measurement time coincided within 5 minutes because the measurement intervals were different between instruments.

  15. Comparison of geostatistical kriging algorithms for intertidal surface sediment facies mapping with grain size data.

    Science.gov (United States)

    Park, No-Wook; Jang, Dong-Ho

    2014-01-01

    This paper compares the predictive performance of different geostatistical kriging algorithms for intertidal surface sediment facies mapping using grain size data. Indicator kriging, which maps facies types from conditional probabilities of predefined facies types, is first considered. In the second approach, grain size fractions are first predicted using cokriging and the facies types are then mapped. As grain size fractions are compositional data, their characteristics should be considered during spatial prediction. For efficient prediction of compositional data, additive log-ratio transformation is applied before cokriging analysis. The predictive performance of cokriging of the transformed variables is compared with that of cokriging of raw fractions in terms of both prediction errors of fractions and facies mapping accuracy. From a case study of the Baramarae tidal flat, Korea, the mapping method based on cokriging of log-ratio transformation of fractions outperformed the one based on cokriging of untransformed fractions in the prediction of fractions and produced the best facies mapping accuracy. Indicator kriging that could not account for the variation of fractions within each facies type showed the worst mapping accuracy. These case study results indicate that the proper processing of grain size fractions as compositional data is important for reliable facies mapping.

  16. Comparison of Geostatistical Kriging Algorithms for Intertidal Surface Sediment Facies Mapping with Grain Size Data

    Directory of Open Access Journals (Sweden)

    No-Wook Park

    2014-01-01

    Full Text Available This paper compares the predictive performance of different geostatistical kriging algorithms for intertidal surface sediment facies mapping using grain size data. Indicator kriging, which maps facies types from conditional probabilities of predefined facies types, is first considered. In the second approach, grain size fractions are first predicted using cokriging and the facies types are then mapped. As grain size fractions are compositional data, their characteristics should be considered during spatial prediction. For efficient prediction of compositional data, additive log-ratio transformation is applied before cokriging analysis. The predictive performance of cokriging of the transformed variables is compared with that of cokriging of raw fractions in terms of both prediction errors of fractions and facies mapping accuracy. From a case study of the Baramarae tidal flat, Korea, the mapping method based on cokriging of log-ratio transformation of fractions outperformed the one based on cokriging of untransformed fractions in the prediction of fractions and produced the best facies mapping accuracy. Indicator kriging that could not account for the variation of fractions within each facies type showed the worst mapping accuracy. These case study results indicate that the proper processing of grain size fractions as compositional data is important for reliable facies mapping.

  17. Normalizing surface electromyographic measures of the masticatory muscles: Comparison of two different methods for clinical purpose.

    Science.gov (United States)

    Mapelli, Andrea; Tartaglia, Gianluca Martino; Connelly, Stephen Thaddeus; Ferrario, Virgilio Ferruccio; De Felicio, Claudia Maria; Sforza, Chiarella

    2016-10-01

    To compare a new normalization technique (wax pad, WAX) with the currently utilized cotton roll (COT) method in surface electromyography (sEMG) of the masticatory muscles. sEMG of the masseter and anterior temporalis muscles of 23 subjects was recorded while performing two repetitions of 5s maximum voluntary clenches (MVC) on COT and WAX. For each task, the mean value of sEMG amplitude and its coefficient of variation were calculated, and the differences between the two repetitions computed. The standard error of measurement (SEM) was calculated. For each subject and muscle, the COT-to-WAX maximum activity increment was computed. Participant preference between tasks was also recorded. WAX MVC tasks had larger maximum EMG amplitude than COT MVC tasks (P0.391) and its coefficient of variation were unchanged (P>0.180). The WAX task was the more comfortable for 18/23 subjects (P=0.007). WAX normalization ensures the same stability level of maximum EMG amplitude as COT normalization, but it is more repeatable, elicits larger maximum muscular contraction, and is felt to be more comfortable by subjects. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Comparison of resistance to corrosion on haz of a ferritic stainless steel by different surface finishings

    Directory of Open Access Journals (Sweden)

    Juvenilson Costa Damascena

    2015-10-01

    Full Text Available Certain techniques, comprising machining and GTAW dressing, have been used in the weld bead edge (region of the welded joint between the weld metal and the base metal to increase the fillet radius of the region by reducing the stress concentrator factor, decreasing roughness, and increasing the life of weldings. Moreover, TIG Dressing may also provide a smooth change in the radius of the curvature and change the average grain size and promote a microstructural variation through the reflow of this region. Current study analyzes the effect of surface finish of the Heat Affected Zone (HAZ on resistance to corrosion of welded joints of simple deposition under plate by using machining techniques with sandpaper of different particle sizes and GTAW Dressing, comparing the effect of the two techniques in the resistance to corrosion in environments with chloride ions. ACE P410D ferritic stainless steel was employed as base metal and austenitic wire 308L for welding. Results showed that the condition sweetened with GTAW Dressing with pure argon at current 100A generated the lowest mass loss among the conditions under analysis.

  19. Vertical Profiles of Aerosol Optical Properties Over Central Illinois and Comparison with Surface and Satellite Measurements

    Science.gov (United States)

    Sheridan P. J.; Andrews, E.; Ogren, J A.; Tackett, J. L.; Winker, D. M.

    2012-01-01

    Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1) measure the in situ aerosol properties and determine their vertical and temporal variability and (2) relate these aircraft measurements to concurrent surface and satellite measurements. Underflights of the CALIPSO satellite show reasonable agreement in a majority of retrieved profiles between aircraft-measured extinction at 532 nm (adjusted to ambient relative humidity) and CALIPSO-retrieved extinction, and suggest that routine aircraft profiling programs can be used to better understand and validate satellite retrieval algorithms. CALIPSO tended to overestimate the aerosol extinction at this location in some boundary layer flight segments when scattered or broken clouds were present, which could be related to problems with CALIPSO cloud screening methods. The in situ aircraft-collected aerosol data suggest extinction thresholds for the likelihood of aerosol layers being detected by the CALIOP lidar. These statistical data offer guidance as to the likelihood of CALIPSO's ability to retrieve aerosol extinction at various locations around the globe.

  20. Adhesive contact of rough surfaces: comparison between numerical calculations and analytical theories

    CERN Document Server

    Carbone, Giuseppe; Tartaglino, Ugo; 10.1140/epje/i2009-10508-5

    2010-01-01

    We have employed a numerical procedure to analyze the adhesive contact between a soft elastic layer and a rough rigid substrate. The solution of the problem is obtained by calculating the Green's function which links the pressure distribution to the normal displacements at the interface. The problem is then formulated in the form of a Fredholm integral equation of the first kind with a logarithmic kernel, and the boundaries of the contact area are calculated by requiring that the energy of the system is stationary. The methodology has been employed to study the adhesive contact between an elastic semi-infinite solid and a randomly rough rigid profile with a self-affine fractal geometry. We show that, even in presence of adhesion, the true contact area still linearly depends on the applied load. The numerical results are then critically compared with the prediction of an extended version of the Persson's contact mechanics theory, able to handle anisotropic surfaces, as 1D interfaces. It is shown that, for any ...