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Sample records for measured hcho columns

  1. Mobile Column Measurements of HCHO, NO2, NH3, and C2H6 in Colorado during FRAPPE

    Science.gov (United States)

    Kille, N.; Volkamer, R. M.; Baidar, S.; Ortega, I.; Sinreich, R.; Hannigan, J. W.; Cooper, O. R.; Nussbaumer, E.; Pfister, G.

    2015-12-01

    Gases from anthropogenic sources have the potential to have a profound impact on air quality. Emissions from large cattle feedlots and ONG (Oil and Natural Gas) sites are comprised of NH3 (ammonia) and C2H6 (ethane) as pollutants. C2H6 contributes to photochemical ozone (O3) production and oxidation production of HCHO (formaldehyde). NH3 is a major source for reactive nitrogen to form particulate matter 2.5, which negatively affects human health. NO2 (nitrogen dioxide), emitted during combustion, is considered a large-scale pollutant and contributes to the formation of O3. Deploying an innovative suite of remote sensing instruments in a mobile laboratory, a Multi Axis Differential Optical Absorption Spectrometer (MAX-DOAS), a UV-Vis Spectrometer, and a Fourier Transform Infrared Spectrometer, we obtain mobile column measurements at high spatial and temporal resolution, 2 seconds for the UV-Vis and IR spectrometers and 20 seconds for the MAX-DOAS. Within the scope of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) we measure total columns of HCHO, NO2, NH3, and C2H6 using the University of Colorado mobile laboratory. Emissions of urban areas, agriculture, and ONG sites were studied. For the measurement of total columns the solar occultation flux method has been applied. We measured significant variability in the columns. The measurement of total columns allows one to determine the emission flux and source strength when driving a closed box around or upwind and downwind of a source with the mobile laboratory. We present results from select research drives.

  2. Which processes drive observed variations of HCHO columns over India?

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    Surl, Luke; Palmer, Paul I.; González Abad, Gonzalo

    2018-04-01

    We interpret HCHO column variations observed by the Ozone Monitoring Instrument (OMI), aboard the NASA Aura satellite, over India during 2014 using the GEOS-Chem atmospheric chemistry and transport model. We use a nested version of the model with a horizontal resolution of approximately 25 km. HCHO columns are related to local emissions of volatile organic compounds (VOCs) with a spatial smearing that increases with the VOC lifetime. Over India, HCHO has biogenic, pyrogenic, and anthropogenic VOC sources. Using a 0-D photochemistry model, we find that isoprene has the largest molar yield of HCHO which is typically realized within a few hours. We also find that forested regions that neighbour major urban conurbations are exposed to high levels of nitrogen oxides. This results in depleted hydroxyl radical concentrations and a delay in the production of HCHO from isoprene oxidation. We find that propene is the only anthropogenic VOC emitted in major Indian cities that produces HCHO at a comparable (but slower) rate to isoprene. The GEOS-Chem model reproduces the broad-scale annual mean HCHO column distribution observed by OMI (r = 0.6), which is dominated by a distinctive meridional gradient in the northern half of the country, and by localized regions of high columns that coincide with forests. Major discrepancies are noted over the Indo-Gangetic Plain (IGP) and Delhi. We find that the model has more skill at reproducing observations during winter (JF) and pre-monsoon (MAM) months with Pearson correlations r > 0.5 but with a positive model bias of x≃1×1015 molec cm-2. During the monsoon season (JJAS) we reproduce only a diffuse version of the observed meridional gradient (r = 0.4). We find that on a continental scale most of the HCHO column seasonal cycle is explained by monthly variations in surface temperature (r = 0.9), suggesting a role for biogenic VOCs, in agreement with the 0-D and GEOS-Chem model calculations. We also find that the seasonal cycle during

  3. Mobile mini-DOAS measurement of the outflow of NO2 and HCHO from Mexico City

    Directory of Open Access Journals (Sweden)

    L. Molina

    2009-08-01

    Full Text Available We here present the results from mobile measurements using two ground-based zenith viewing Differential Optical Absorption Spectroscopy (DOAS instruments. The measurement was performed in a cross-section of the plume from the Mexico City Metropolitan Area (MCMA on 10 March 2006 as part of the MILAGRO field campaign. The two instruments operated in the UV and the visible wavelength region respectively and have been used to derive the differential vertical columns of HCHO and NO2 above the measurement route. This is the first time the mobile mini-DOAS instrument has been able to measure HCHO, one of the chemically most important and interesting gases in the polluted urban atmosphere. Using a mass-averaged wind speed and wind direction from the WRF model the instantaneous flux of HCHO and NO2 has been calculated from the measurements and the results are compared to the CAMx chemical model. The calculated flux through the measured cross-section was 1.9 (1.5–2.2 kg/s of HCHO and 4.4 (4.0–5.0 kg/s of NO2 using the UV instrument and 3.66 (3.63–3.73 kg/s of NO2 using the visible light instrument. The modeled values from CAMx for the outflow of both NO2 and HCHO, 1.1 and 3.6 kg/s, respectively, show a reasonable agreement with the measurement derived fluxes.

  4. NO2 and HCHO variability in Mexico City from MAX-DOAS measurements

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    Grutter, M.; Friedrich, M. M.; Rivera, C. I.; Arellano, E. J.; Stremme, W.

    2015-12-01

    Atmospheric studies in large cities are of great relevance since pollution affects air quality and human health. A network of Multi Axis Differential Optical Absorption Spectrometers (MAX-DOAS) has been established in strategic sites within the Mexico City metropolitan area. Four instruments are now in operation with the aim to study the variability and spatial distribution of key pollutants, providing results of O4, NO2 and HCHO slant column densities (SCD). A numerical code has been written to retrieve gas profiles of NO2 and HCHO using radiative transfer simulations. We present the first results of the variability of these trace gases which will bring new insight in the current knowledge of transport patterns, emissions as well as frequency and origin of extraordinary events. Results of the vertical column densities (VCD) valiability of NO2 and HCHO in Mexico City are presented. These studies are useful to validate current and future satellite observatopns such as OMI, TROPOMI and TEMPO.

  5. MAX-DOAS measurements of NO2, HCHO and CHOCHO at a rural site in Southern China

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    Li, X.; Brauers, T.; Hofzumahaus, A.; Lu, K.; Li, Y. P.; Shao, M.; Wagner, T.; Wahner, A.

    2013-02-01

    We performed MAX-DOAS measurements during the PRIDE-PRD2006 campaign in the Pearl River Delta region (PRD), China, for 4 weeks in July 2006 at a site located 60 km north of Guangzhou. The vertical distributions of NO2, HCHO, and CHOCHO were independently retrieved by an automated iteration method. The NO2 mixing ratios measured by MAX-DOAS showed reasonable agreement with the simultaneous, ground based in-situ data. The tropospheric NO2 vertical column densities (VCDs) observed by OMI on board EOS-Aura satellite were higher than with those by MAX-DOAS. The 3-D chemical transport model CMAQ overestimated the NO2 VCDs as well as the surface concentrations by about 65%. From this observation, a reduction of NOx emission strength in CMAQ seems to be necessary in order to well reproduce the NO2 observations. The average mixing ratios of HCHO and CHOCHO were 7 ppb and 0.4 ppb, respectively, higher than in other rural or semirural environments. The high ratio of 0.062 between CHOCHO and HCHO corresponds to the high VOCs reactivity and high HOx turnover rate consistent with other observations during the campaign.

  6. Ship-based MAX-DOAS measurements of tropospheric NO2, SO2, and HCHO distribution along the Yangtze River

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    Hong, Qianqian; Liu, Cheng; Chan, Ka Lok; Hu, Qihou; Xie, Zhouqing; Liu, Haoran; Si, Fuqi; Liu, Jianguo

    2018-04-01

    In this paper, we present ship-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of tropospheric trace gases' distribution along the Yangtze River during winter 2015. The measurements were performed along the Yangtze River between Shanghai and Wuhan, covering major industrial areas in eastern China. Tropospheric vertical column densities (VCDs) of nitrogen dioxide (NO2), sulfur dioxide (SO2), and formaldehyde (HCHO) were retrieved using the air mass factor calculated by the radiative transfer model. Enhanced tropospheric NO2 and SO2 VCDs were detected over downwind areas of industrial zones over the Yangtze River. In addition, spatial distributions of atmospheric pollutants are strongly affected by meteorological conditions; i.e., positive correlations were found between concentration of pollutants and wind speed over these areas, indicating strong influence of transportation of pollutants from high-emission upwind areas along the Yangtze River. Comparison of tropospheric NO2 VCDs between ship-based MAX-DOAS and Ozone Monitoring Instrument (OMI) satellite observations shows good agreement with each other, with a Pearson correlation coefficient (R) of 0.82. In this study, the NO2 / SO2 ratio was used to estimate the relative contributions of industrial sources and vehicle emissions to ambient NO2 levels. Analysis results of the NO2 / SO2 ratio show a higher contribution of industrial NO2 emissions in Jiangsu Province, while NO2 levels in Jiangxi and Hubei provinces are mainly related to vehicle emissions. These results indicate that different pollution control strategies should be applied in different provinces. In addition, multiple linear regression analysis of ambient carbon monoxide (CO) and odd oxygen (Ox) indicated that the primary emission and secondary formation of HCHO contribute 54.4 ± 3.7 % and 39.3 ± 4.3 % to the ambient HCHO, respectively. The largest contribution from primary emissions in winter suggested that

  7. Identification of tropospheric emissions sources from satellite observations: Synergistic use of HCHO, NO2, and SO2 trace gas measurements

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    Marbach, T.; Beirle, S.; Khokhar, F.; Platt, U.

    2005-12-01

    We present case studies for combined HCHO, NO2, and SO2 satellite observations, derived from GOME measurements. Launched on the ERS-2 satellite in April 1995, GOME has already performed continuous operations over 8 years providing global observations of the different trace gases. In this way, satellite observations provide unique opportunities for the identifications of trace gas sources. The satellite HCHO observations provide information concerning the localization of biomass burning (intense source of HCHO). The principal biomass burning areas can be observed in the Amazon basin region and in central Africa Weaker HCHO sources (south east of the United States, northern part of the Amazon basin, and over the African tropical forest), not correlated with biomass burning, could be due to biogenic isoprene emissions. The HCHO data can be compared with NO2 and SO2 results to identify more precisely the tropospheric sources (biomass burning events, human activities, additional sources like volcanic emissions). Biomass burning are important tropospheric sources for both HCHO and NO2. Nevertheless HCHO reflects more precisely the biomass burning as it appears in all biomass burning events. NO2 correlate with HCHO over Africa (grassland fires) but not over Indonesia (forest fires). In south America, an augmentation of the NO2 concentrations can be observed with the fire shift from the forest to grassland vegetation. So there seems to be a dependence between the NO2 emissions during biomass burning and the vegetation type. Other high HCHO, SO2, and NO2 emissions can be correlated with climatic events like the El Nino in 1997, which induced dry conditions in Indonesia causing many forest fires.

  8. On the use of harmonized HCHO and NO2 MAXDOAS measurements for the validation of GOME-2 and OMI satellite sensors

    Science.gov (United States)

    Pinardi, Gaia; Hendrick, François; Gielen, Clio; Van Roozendael, Michel; De Smedt, Isabelle; Lambert, Jean-Christopher; Granville, José; Compernolle, Steven; Richter, Andreas; Peters, Enno; Piters, Ankie; Wagner, Thomas; Wang, Yang; Drosoglou, Theano; Bais, Alkis; Wang, Shanshan; Saiz-Lopez, Alfonso

    2017-04-01

    During the last decade, the MAXDOAS technique has been increasingly recognized as a source of Fiducial Reference Measurements (FRM) suitable for the validation of satellite nadir observations of species relevant for climate and air quality like NO2 and HCHO. As part of the EU FP7 QA4ECV (Quality Assurance for Essential Climate Variables; see http://www.qa4ecv.eu/) project, efforts have been recently made to harmonize a network of a dozen of MAXDOAS spectrometers in view of their use to assess the quality of satellite climate data records generated within the same project. Harmonization tasks have addressed both retrieval steps involved in MAXDOAS retrievals, i.e. the DOAS spectral fit providing the differential slant column densities (DSCDs) and the conversion of the retrieved DSCDs into vertical profiles and/or vertical column densities (VCDs). In this work, we illustrate the successive harmonization steps and present the resulting QA4ECV MAXDOAS database v2. The approach adopted for the conversion of slant to vertical columns is based on a simplified look-up-table approach. The strength and limitation of this approach are discussed using reference data retrieved using an optimal estimation scheme. The QA4ECV MAXDOAS database is then used to validate satellite data sets of NO2 and HCHO columns derived from the Aura/OMI and MetOp/GOME-2 sensors. The methodology of comparison, which is also a subject of the QA4ECV project, is reviewed with respect to co-location criteria, impact of vertical and horizontal smoothing and representativeness of validation sites. We conclude by assessing the current strengths and limitations of the existing MAXDOAS datasets for NO2 and HCHO satellite validation.

  9. Comparison between premixed and partially premixed combustion in swirling jet from PIV, OH PLIF and HCHO PLIF measurements

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    Lobasov, A. S.; Chikishev, L. M.; Dulin, V. M.

    2017-09-01

    The present paper reports on the investigation of fuel-rich and fuel-lean turbulent combustion in a high-swirl jet. The jet flow was featured by a breakdown of the vortex core, presence of the central recirculation zone and intensive precession of the flow. The measurements were performed by the stereo PIV, OH PLIF and HCHO PLIF techniques, simultaneously. Fluorescence of OH* in the flame and combustion products was excited via transition in the (1,0) vibrational band of the A2Σ+ - X2Π electronic system. The fluorescence was detected in the spectral range of 305-320 nm. In the case of HCHO PLIF measurements the A-X {4}01 transition was excited. The jet Reynolds number was fixed as 5 000 (the bulk velocity was U 0 = 5 m/s). Three cases of the equivalence ratio ϕ of methane/air mixture issued from the nozzle were considered 0.7, 1.4 and 2.5. In all cases the flame front was subjected to deformations due to large-scale vortices, which rolled-up in the inner (around the central recirculation zone) and outer (between the annular jet core and surrounding air) mixing layers.

  10. The Unique OMI HCHO/NO2 Feature During the 2008 Beijing Summer Olympics: Implications for Ozone Production Sensitivity

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    Witte, J. C.; Duncan, B. N.; Douglass, A. R.; Kurosu, T. P.; Chance, K.; Retscher, C.

    2010-01-01

    In preparation of the Beijing Summer Olympic and Paralympics Games, strict controls were imposed between July and September 2008 on motor vehicle traffic and industrial emissions to improve air quality for the competitors. We assessed chemical sensitivity of ozone production to these controls using Ozone Monitoring Instrument (OMI) column measurements of formaldehyde (HCHO) and nitrogen dioxide (NO2), where their ratio serves as a proxy for the sensitivity. During the emission controls, HCHO/NO2 increased and indicated a NOx-limited regime, in contrast to the same period in the preceding three years when the ratio indicates volatile organic carbon (VOC)-limited and mixed NOx-VOC-limited regimes. After the emission controls were lifted, observed NO2 and HCHO/NO2 returned to their previous values. The 2005-2008 OMI record shows that this transition in regimes was unique as ozone production in Beijing was rarely NOx-limited. OMI measured summertime increases in HCHO of around 13% in 2008 compared to prior years, the same time period during which MODIS vegetation indices increased. The OMI HCHO increase may be due to higher biogenic emissions of HCHO precursors, associated with Beijing's greening initiative for the Olympics. However, NO2 and HCHO were also found to be well-correlated during the summer months. This indicates an anthropogenic VOC contribution from vehicle emissions to OMI HCHO and is a plausible explanation for the relative HCHO minimum observed in August 2008, concurrent with a minimum in traffic emissions. We calculated positive trends in 2005-2008 OMI HCHO and NO2 of about +1 x 10(exp 14) Molec/ square M-2 and +3 x 10(exp 13) molec CM-2 per month, respectively. The positive trend in NO2 may be an indicator of increasing vehicular traffic since 2005, while the positive trend in HCHO may be due to a combined increase in anthropogenic and biogenic emissions since 2005.

  11. Retrieval of tropospheric HCHO in El Salvador using ground based DOAS

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    Abarca, W.; Gamez, K.; Rudamas, C.

    2017-12-01

    Formaldehyde (HCHO) is the most abundant carbonyl in the atmosphere, being an intermediate product in the oxidation of most volatile organic compounds (VOCs). HCHO is carcinogenic, and highly water soluble [1]. HCHO can originate from biomass burning and fossil fuel combustion and has been observed from satellite and ground-based sensors by using the Differential Optical Absorption Spectroscopy (DOAS) technique [2].DOAS products can be used for air quality monitoring, validation of chemical transport models, validation of satellite tropospheric column density retrievals, among others [3]. In this study, we report on column density levels of HCHO measured by ground based Multi-Axis -DOAS in different locations of El Salvador in March, 2015. We have not observed large differences of the HCHO column density values at different viewing directions. This result points out a reasonably polluted and hazy atmosphere in the measuring sites, as reported by other authors [4]. Average values ranging from 1016 to 1017 molecules / cm2 has been obtained. The contribution of vehicular traffic and biomass burning to the column density levels in these sites of El Salvador will be discussed. [1] A. R. Garcia et al., Atmos. Chem. Phys. 6, 4545 (2006) [2] E. Peters et al., Atmos. Chem. Phys. 12, 11179 (2012) [3] T. Vlemmix, et al. Atmos. Meas. Tech., 8, 941-963, 2015 [4] A. Heckel et al., Atmos. Chem. Phys. 5, (2005)

  12. MAX-DOAS formaldehyde slant column measurements during CINDI: intercomparison and analysis improvement

    Directory of Open Access Journals (Sweden)

    G. Pinardi

    2013-01-01

    Full Text Available We present intercomparison results for formaldehyde (HCHO slant column measurements performed during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI that took place in Cabauw, the Netherlands, in summer 2009. During two months, nine atmospheric research groups simultaneously operated MAX-DOAS (MultiAXis Differential Optical Absorption Spectroscopy instruments of various designs to record UV-visible spectra of scattered sunlight at different elevation angles that were analysed using common retrieval settings. The resulting HCHO data set was found to be highly consistent, the mean difference between instruments generally not exceeding 15% or 7.5 × 1015 molec cm−2, for all viewing elevation angles. Furthermore, a sensitivity analysis was performed to investigate the uncertainties in the HCHO slant column retrieval when varying key input parameters such as the molecular absorption cross sections, correction terms for the Ring effect or the width and position of the fitting interval. This study led to the identification of potentially important sources of errors associated with cross-correlation effects involving the Ring effect, O4, HCHO and BrO cross sections and the DOAS closure polynomial. As a result, a set of updated recommendations was formulated for HCHO slant column retrieval in the 336.5–359 nm wavelength range. To conclude, an error budget is proposed which distinguishes between systematic and random uncertainties. The total systematic error is estimated to be of the order of 20% and is dominated by uncertainties in absorption cross sections and related spectral cross-correlation effects. For a typical integration time of one minute, random uncertainties range between 5 and 30%, depending on the noise level of individual instruments.

  13. Characterizing boundary layer height using surface and column measurements of NO2 and formaldehyde

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    Valin, L.; Szykman, J.; Long, R.; Whitehill, A.; Williams, D. J.; Knepp, T. N.; Crawford, J. H.; Al-Saadi, J. A.; Judd, L.; Brown, S.; Matichuk, R.; Tonnesen, G.; Appel, W.; Hogrefe, C.; Abuhassan, N.; Cede, A.; Spinei, E.; Herman, J. R.; Swap, R.; Cohen, R. C.; Fried, A.; Weinheimer, A. J.

    2017-12-01

    The rate of vertical mixing near the surface determines the rate of human exposure to emitted pollutants and also influences the rate at which ozone and particulate matter are formed. To characterize the variability of atmospheric composition near the surface and above, the EPA Office of Research and Development has deployed instruments to measure surface and column concentrations of NO2, an emitted species, and formaldehyde (HCHO) during KORUS-AQ (May - June 2016, Seoul, Korea), UWFPS (Jan-Feb 2016, Salt Lake City) and LMOS (May - June, 2017, Lake Michigan). We compare the mixed layer height determined by aerosol backscatter profiles to a value determined by dividing the NO2 and HCHO column density (molecule cm-2) by its surface concentration (molecule cm-3), using linear regression to remove influence of layers aloft (y-intercept), such as subtraction of the stratospheric NO2 column. We evaluate our findings by using aircraft soundings of NO2 and HCHO and discuss the implications with respect to photochemical transport modeling results from CMAQ and space-based satellite retrievals. Finally we discuss an overall strategy to make these measurements part of routine monitoring at Photochemical Assessment Monitoring System locations (PAMS).

  14. 3 dimensional distributions of NO2, CHOCHO, and HCHO measured by the University of Colorado 2D-MAX-DOAS during MAD-CAT

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    Ortega, Ivan; Sinreich, Roman; Volkamer, Rainer

    2014-05-01

    We present results of 2 dimensional Multi Axis-DOAS (2D-MAX-DOAS) measurements to infer 3-dimensional measurements of trace gases by characterizing boundary layer vertical profiles and near surface azimuth horizontal distribution of NO2 (14 angles covering 360°). We combine the established optimal estimation inversion with a new parameterization approach; the first method to derive NO2 tropospheric vertical profiles and boundary layer height and the second one to retrieve the azimuth horizontal distribution of near surface NO2 mixing ratios, both at multiple wavelengths (350 nm, 450 nm, and 560 nm). This was conducted for three cloud-free days in the framework of the intensive Multi Axis DOAS Comparison campaign for Aerosols and Trace gases (MAD-CAT) in Mainz, Germany 2013. By retrieving NO2 at multiple wavelengths range-resolved distributions of NO2 are derived using an 'Onion-peeling' approach, i.e., exploiting the fact that the optical path lengths at different wavelengths probe different horizontal air masses. We also measure glyoxal (CHOCHO) and formaldehyde (HCHO) distributions, and present to our knowledge the first 3-dimesional trace-gas distribution measurements of CHOCHO by a ground-based instrument. We expand the 2D-MAX-DOAS capabilities to calculate azimuth ratios of HCHO-to-NO2 (RFN) and CHOCHO-to-NO2 (RGN) to pinpoint volatile organic compound (VOC) oxidation chemistry and CHOCHO-to-HCHO (RGF) ratios as an indicator of biogenic and/or anthropogenic VOC emissions. The results of RFN correlate well with RGN and we identify azimuth variations that indicate gradients in the VOC/NOx chemistry that leads to O3 and secondary aerosol production. While there is a clear diurnal pattern in the RFN and RGN, no such variations are observed in the RGF, which shows rather constant values below 0.04 throughout the day, consistent with previous measurements, and indicative of urban air masses.

  15. Laser-Based and Ultra-Portable Gas Sensor for Indoor and Outdoor Formaldehyde (HCHO) Monitoring

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    Shutter, J. D.; Allen, N.; Paul, J.; Thiebaud, J.; So, S.; Scherer, J. J.; Keutsch, F. N.

    2017-12-01

    While used as a key tracer of oxidative chemistry in the atmosphere, formaldehyde (HCHO) is also a known human carcinogen and is listed and regulated by the United States EPA as a hazardous air pollutant. Combustion processes and photochemical oxidation of volatile organic compounds (VOCs) are the major outdoor sources of HCHO, and building materials and household products are ubiquitous sources of indoor HCHO. Due to the ease with which humans can be exposed to HCHO, it is imperative to monitor levels of both indoor and outdoor HCHO exposure in both short and long-term studies.High-quality direct and indirect methods of quantifying HCHO mixing ratios exist, but instrument size and user-friendliness can make them cumbersome or impractical for certain types of indoor and long-term outdoor measurements. In this study, we present urban HCHO measurements by using a new, commercially-available, ppbv-level accurate HCHO gas sensor (Aeris Technologies' MIRA Pico VOC Laser-Based Gas Analyzer) that is highly portable (29 cm x 20 cm x 10 cm), lightweight (3 kg), easy-to-use, and has low power (15 W) consumption. Using an ultra-compact multipass cell, an absorption path length of 13 m is achieved, resulting in a sensor capable of achieving ppbv/s sensitivity levels with no significant spectral interferences.To demonstrate the utility of the gas sensor for emissions measurements, a GPS was attached to the sensor's housing in order to map mobile HCHO measurements in real-time around the Boston, Massachusetts, metro area. Furthermore, the sensor was placed in residential and industrial environments to show its usefulness for indoor and outdoor pollution measurements. Lastly, we show the feasibility of using the HCHO sensor (or a network of them) in long-term monitoring stations for hazardous air pollutants.

  16. Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air

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    Lui, K. H.; Ho, Steven Sai Hang; Louie, Peter K. K.; Chan, C. S.; Lee, S. C.; Hu, Di; Chan, P. W.; Lee, Jeffrey Chi Wai; Ho, K. F.

    2017-03-01

    Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012-2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).

  17. Measurement of dihydro testosterone by radioimmunoassay after celite column chromatography

    International Nuclear Information System (INIS)

    Lando, V.S.

    1992-01-01

    A method for measuring dihydro testosterone after celite column chromatography is developed. One milliliter of serum containing 1000 cpm of tritiated dihydro testosterone was extracted with hexane: ethyl acetate (2:3): dried, diluted with non saturated iso octane and injected in the column previously washed with 3.5 ml of pure iso octane. The serum was eluted from the column with pure iso octane (3.5 ml) followed by 5% ethyl acetate in iso octane. The quantity of tritiated dihydro testosterone which was recovered ranged from 50% to 80% in all assays. The sensitivity of the method was 4 ng/d l. The intra-assay variation was less than 9% and the inter-assay variation was less than 9,7%. It was measured dihydro testosterone, testosterone and testosterone/dihydro testosterone ratio in the following groups: Group 1- forty-one normal adult subjects in basal conditions, Group 2 - six normal adult subjects, evaluated in basal conditions and after stimulus with 6000 International Unity of human Chorionic Gonadotropin; Group 3- six pre-puberal children with unilateral cryptochidism. Group 4- eight patients with male pseudo hermaphroditism due to 5-alpha-reductase deficiency in basal conditions and after HCG. (author)

  18. Pulsed Airborne Lidar Measurements of C02 Column Absorption

    Science.gov (United States)

    Abshire, James B.; Riris, Haris; Allan, Graham R.; Weaver, Clark J.; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William E.; Rodriquez, Michael; Browell, Edward V.

    2011-01-01

    We report on airborne lidar measurements of atmospheric CO2 column density for an approach being developed as a candidate for NASA's ASCENDS mission. It uses a pulsed dual-wavelength lidar measurement based on the integrated path differential absorption (IPDA) technique. We demonstrated the approach using the CO2 measurement from aircraft in July and August 2009 over four locations. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The 2009 measurements have been analyzed in detail and the results show approx.1 ppm random errors for 8-10 km altitudes and approx.30 sec averaging times. Airborne measurements were also made in 2010 with stronger signals and initial analysis shows approx. 0.3 ppm random errors for 80 sec averaging times for measurements at altitudes> 6 km.

  19. Nondestructive measurement for radionuclide concentration distribution in soil column

    International Nuclear Information System (INIS)

    Ogawa, Hiromichi; Ohnuki, Toshihiko; Yamamoto, Tadatoshi; Wadachi, Yoshiki

    1985-01-01

    A nondestructive method has been studied for determining the concentration of radionuclide (Cs-137) distributed in a soil column. The concentration distribution was calculated from the counting rate distribution using the efficiency matrix of a detector. The concentration distribution obtained by this method, with measuring efficiencies of theoretical calculation, coincides well with that obtained by the destructive sampling method. This method is, therefore, found to be effective for the measurement of one dimensional concentration distribution. The measuring limit of this method is affected not only by the radionuclide concentration but also by the shape of concentration distribution in a soil column and also by the way it is divided into concentration blocks. It is found that, the radioactive concentration up to 2.6 x 10 -4 μCi/g (9.62 Bq/g), and also the distribution up to where the concentration reduces to half at every 1 cm of depth, can be measured by this system. The concentration blocks can be divided into 1 cm of thickness as a minimum value. (author)

  20. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the COFFEE Instrument

    Science.gov (United States)

    Marrero, Josette; St. Clair, Jason; Yates, Emma; Swanson, Andrew; Gore, Warren; Iraci, Laura; Hanisco, Thomas

    2016-04-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. We will present results from flights performed over the Central Valley of California, including boundary layer measurements and vertical profiles in the tropospheric column. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. These results will be presented in conjunction with formaldehyde. Targets in the Central Valley consist of an oil field, agricultural areas, and highways, each of which can emit HCHO primarily and generate HCHO through secondary production. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  1. OMI satellite observed formaldehyde column from 2006 to 2015 over Xishuangbanna, southwest China, and validation using ground based zenith-sky DOAS.

    Science.gov (United States)

    Liu, Rui; Feng, Tao; Wang, Shanshan; Shi, Chanzhen; Guo, Yanlin; Nan, Jialiang; Deng, Yun; Zhou, Bin

    2018-02-01

    Formaldehyde (HCHO) provides a proxy to reveal the isoprene and biogenic volatile organic compounds emission which plays important roles in atmospheric chemical process and climate change. The ground-based observation with zenith-sky DOAS is carried out in order to validate the HCHO columns from OMI. It has a good correlation of 0.71678 between the HCHO columns from two sources. Then we use the OMI HCHO columns from January 2006 to December 2015 to indicate the interannual variation and spatial distribution in Xishuangbanna. The HCHO concentration peaks appeared in March or April for each year significantly corresponding to the intensive fire counts at the same time, which illustrate that the high HCHO columns are strongly influenced by the biomass burning in spring. Temperature and precipitation are also the important influence factors in the seasonal variation when there is nearly no biomass burning. The spatial patterns over the past ten years strengthen the deduction from the temporal variation and show the relationship with land cover and land use, elevation and population density. It is concluded that the biogenic activity plays a role in controlling the background level of HCHO in Xishuangbanna, while biomass burning is the main driving force of high HCHO concentration. And forests are greater contributor to HCHO rather than rubber trees which cover over 20% of the land in the region. Moreover, uncertainties from HCHO slant column retrieval and AMFs calculation are discussed in detail. Copyright © 2017. Published by Elsevier B.V.

  2. Fabrication of a micrometer Ni–Cu alloy column coupled with a Cu micro-column for thermal measurement

    International Nuclear Information System (INIS)

    Lin, J C; Chang, T K; Yang, J H; Jeng, J H; Lee, D L; Jiang, S B

    2009-01-01

    Micrometer Ni–Cu alloy columns have been fabricated by the micro-anode-guided electroplating (MAGE) process in the citrate bath. The surface morphology and chemical composition of the micro-columns were determined by copper concentration in the bath and by the electrical bias of MAGE. When fabricated in a bath of dilute copper (i.e. 4 mM) at lower voltages (e.g. 3.8 and 4.0 V), the alloy micro-columns revealed uniform diameter and smooth appearance. The alloy composition demonstrated an increase in the wt% ratio of Ni/Cu from 75/25, 80/20, 83/17 to 87/13 with increasing electrical bias from 3.8, 4.0, 4.2 to 4.4 V. However, it decreases from 75/25, 57/43 to 47/53 with increasing copper concentration from 4, 8 to 12 mM in the bath. Citrate plays a role in forming complexes with nickel and copper at similar reduction potentials, thus reducing simultaneously to Ni–Cu alloy. The mechanism for fabricating alloy micro-columns could be delineated on the basis of cathodic polarization of the complexes. A couple of micro-columns were fabricated using MAGE in constructing a pure copper micro-column on the top of a Ni/Cu (at 47/53) alloy micro-column. This micro-thermocouple provides a satisfactory measurement with good sensitivity and precision

  3. Measurement of capacity coefficient of inclined liquid phase catalytic exchange column for tritiated water processing

    International Nuclear Information System (INIS)

    Yamai, Hideki; Konishi, Satoshi; Yamanishi, Toshihiko; Okuno, Kenji

    1994-01-01

    Liquid phase catalytic exchange (LPCE) is effective method for enrichment and removal of tritium from tritiated water. Capacity coefficients of operating LPCE column that are essential to evaluate column performance were measured. Experiments were performed with short catalyst packed columns and effect of inclination was studied. Method for evaluation of capacity coefficients was established from measurement of isotope concentration of liquid, vapor, gas phases at the two ends of the column. The capacity coefficients were measured under various superficial gas velocities. Feasibility study of helical columns with roughened inner surface was performed with short inclined columns. The column performance was not strongly affected by the inclination. The result indicates technological feasibility of helical LPCE column, that is expected to have operation stability and reduced height

  4. Locating karst depressed columns by means of Rn measurement on the surface

    International Nuclear Information System (INIS)

    Tang Daimao; Liu Hongfu; Duan Hongjie; Duan Lindi; Sui Haichen

    1999-01-01

    The coal mining and the related surface projects are extremely harassed by the underground karst depressed columns. The author discussed the surface Rn concentration's abnormality caused by the karst depressed columns. It is concluded that different kinds of karst depressed column can cause different Rn concentration's abnormality. The α-cup Rn measuring instrument was used for detecting Rn abnormality on the surface in order to locate the underground karst depressed columns

  5. Equipment for automatic measurement of gamma activity distribution in a column

    International Nuclear Information System (INIS)

    Kalincak, M.; Machan, V.; Vilcek, S.; Balkovsky, K.

    1978-01-01

    The design of a device for stepwise scanning of gamma activity distributions along chromatographic columns is described. In connection with a single-channel gamma spectrometer and a counting ratemeter with a recorder this device permits the resolution of a number of gamma emitters on the column, the determination of the gamma nuclide content in different chemical forms in the sample by means of column separation methods - Gel Chromatography Columns Scanning Method - and the determination of gamma nuclide distribution along the columns. The device permits the scanning of columns of up to 20 mm in diameter and 700 mm in length and continual scanning over a 450 mm column length with one clamping. With minor adaptations it is possible to scan columns up to 30 mm in diameter. The length of the scanned sections is 5 or 10 mm, the scanning time setting is arbitrary and variable activity levels and radiation energies may be measured. (author)

  6. Wire-Mesh Tomography Measurements of Void Fraction in Rectangular Bubble Columns

    International Nuclear Information System (INIS)

    Reddy Vanga, B.N.; Lopez de Bertodano, M.A.; Zaruba, A.; Prasser, H.M.; Krepper, E.

    2004-01-01

    Bubble Columns are widely used in the process industry and their scale-up from laboratory scale units to industrial units have been a subject of extensive study. The void fraction distribution in the bubble column is affected by the column size, superficial velocity of the dispersed phase, height of the liquid column, size of the gas bubbles, flow regime, sparger design and geometry of the bubble column. The void fraction distribution in turn affects the interfacial momentum transfer in the bubble column. The void fraction distribution in a rectangular bubble column 10 cm wide and 2 cm deep has been measured using Wire-Mesh Tomography. Experiments were performed in an air-water system with the column operating in the dispersed bubbly flow regime. The experiments also serve the purpose of studying the performance of wire-mesh sensors in batch flows. A 'wall peak' has been observed in the measured void fraction profiles, for the higher gas flow rates. This 'wall peak' seems to be unique, as this distribution has not been previously reported in bubble column literature. Low gas flow rates yielded the conventional 'center peak' void profile. The effect of column height and superficial gas velocity on the void distribution has been investigated. Wire-mesh Tomography also facilitates the measurement of bubble size distribution in the column. This paper presents the measurement principle and the experimental results for a wide range of superficial gas velocities. (authors)

  7. A technique using a stellar spectrographic plate to measure terrestrial ozone column depth

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Alec Y. [Univ. of California, Berkeley, CA (United States)

    1995-08-01

    This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.

  8. Airborne In-Situ Measurements of Formaldehyde over California: One Year of Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    Science.gov (United States)

    Marrero, J. E.; St Clair, J. M.; Yates, E. L.; Ryoo, J. M.; Gore, W.; Swanson, A. K.; Iraci, L. T.; Hanisco, T. F.

    2016-12-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role in multiple atmospheric processes, such as ozone (O3) production in polluted environments. Due to its short lifetime of only a few hours in daytime, HCHO also serves as tracer of recent photochemical activity. While photochemical oxidation of non-methane hydrocarbons is the dominant source, HCHO can also be emitted directly from fuel combustion, vegetation, and biomass burning. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument was built for integration onto the Alpha Jet Atmospheric eXperiment (AJAX) payload, based out of NASA's Ames Research Center (Moffett Field, CA). Using Non-Resonant Laser Induced Fluorescence (NR-LIF), trace concentrations of HCHO can be detected with a sensitivity of 200 parts per trillion. Since its first research flight in December 2015, COFFEE has successfully flown on more than 20 science missions throughout California and Nevada. Presented here are results from these flights, including boundary layer measurements and vertical profiles throughout the tropospheric column. California's San Joaquin Valley is a primary focus, as this region is known for its elevated levels of HCHO as well as O3. Measurements collected in wildfire plumes, urban centers, agricultural lands, and on and off shore comparisons will be presented. In addition, the correlation of HCHO to other trace gases also measured by AJAX, including O3, methane, carbon dioxide, and water vapor will also be shown. Lastly, the implications of these HCHO measurements on calibration and validation of remote sensing data collected by NASA's OMI (Aura) and OMPS (SuomiNPP) satellites will be addressed.

  9. Measurement of Mo-99 column activity in the evaluation of Mo-99/Tc-99m generator

    International Nuclear Information System (INIS)

    Kuster, Z.

    1994-01-01

    In order to calculate the real elution efficiency of Mo-99/Tc-99m generator the Mo-99 content on the column has to be previously determined. As found in this work, the external measurement of Mo-99-column activity by means of Geiger-Mueller counter is a simple, fast and reliable method. Generally, Mo-99-column is placed slightly out of the center of the generator; therefore the externally measured flux of photons (φ) is an angular-dependent function. If the thickness of the lead container is radially uniform, the flux measured at some distance from the generator (which is rotated in 2π/3 steps) is given by the equation φ = A (1 + Bcos (α-2π(i - 2)/3)) -1 , i=1,2 or 3 (Eq.1) where A is a numerical constant depending on the Mo-99-column activity, B is a numerical constant depending on the Mo-99- column position within the lead container, the angle α depends on the initial orientation of the generator. A total of 20 generator were studied. The measured Mo-99-column activities (Capintec dose calibrator) were in the range 13.1- 35.11 GBq. Contrary to the findings of Vinberg and Kristensen (Eur J Nucl Med 1/1976(219), values of A (Eq. 1) are in good correlation (r 2 =0.9794) with the measured Mo-99-column activities. (author)

  10. Global and Seasonal Distributions of CHOCHO and HCHO Observed by the Ozone Monitoring Instrument on EOS Aura

    Science.gov (United States)

    Kurosu, T. P.; Fu, T.; Volkamer, R.; Millet, D. B.; Chance, K.

    2006-12-01

    Over the two years since its launch in July 2004, the Ozone Monitoring Instrument (OMI) on EOS Aura has demonstrated the capability to routinely monitor the volatile organic compounds (VOCs) formaldehyde (HCHO) and glyoxal (CHOCHO). OMI's daily global coverage and spatial resolution as high as 13x24 km provides a unique data set of these molecules for the study of air quality from space. We present the first study of global seasonal distributions of CHOCHO from space, derived from a year of OMI observations. CHOCHO distributions are compared to simultaneous retrievals of HCHO from OMI, providing a first indication of seasonally resolved ratios of these VOCs on a global scale. Satellite retrievals are compared to global simulations of HCHO and CHOCHO, based on current knowledge of sources and sinks, using the GEOS-Chem global chemistry and transport model. Formaldehyde is both directly emitted and also produced from the oxidation of many VOCs, notably biogenic isoprene, and is removed by photolysis and oxidation. Precursors of glyoxal include isoprene, monoterpenes, and aromatics from anthropogenic, biogenic, and biomass burning emissions; it is removed by photolysis, oxidation by OH, dry/wet deposition, and aerosol uptake. As a case study, satellite observations will also be compared to ground-based measurements taken during the Pearl River Delta 2006 field campaign near Guangzhou, China, where high glyoxal concentrations are frequently observed from space.

  11. Characterisation of Central-African emissions based on MAX-DOAS measurements, satellite observations and model simulations over Bujumbura, Burundi.

    Science.gov (United States)

    Gielen, Clio; Hendrick, Francois; Pinardi, Gaia; De Smedt, Isabelle; Stavrakou, Trissevgeni; Yu, Huan; Fayt, Caroline; Hermans, Christian; Bauwens, Maité; Ndenzako, Eugene; Nzohabonayo, Pierre; Akimana, Rachel; Niyonzima, Sébastien; Müller, Jean-Francois; Van Roozendael, Michel

    2016-04-01

    Central Africa is known for its strong biogenic, pyrogenic, and to a lesser extent anthropogenic emissions. Satellite observations of species like nitrogen dioxide (NO2) and formaldehyde (HCHO), as well as inverse modelling results have shown that there are large uncertainties associated with the emissions in this region. There is thus a need for additional measurements, especially from the ground, in order to better characterise the biomass-burning and biogenic products emitted in this area. We present MAX-DOAS measurements of NO2, HCHO, and aerosols performed in Central Africa, in the city of Bujumbura, Burundi (3°S, 29°E, 850m). A MAX-DOAS instrument has been operating at this location by BIRA-IASB since late 2013. Aerosol-extinction and trace-gases vertical profiles are retrieved by applying the optimal-estimation-based profiling tool bePRO to the measured O4, NO2 and HCHO slant-column densities. The MAX-DOAS vertical columns and profiles are used for investigating the diurnal and seasonal cycles of NO2, HCHO, and aerosols. Regarding the aerosols, the retrieved AODs are compared to co-located AERONET sun photometer measurements for verification purpose, while in the case of NO2 and HCHO, the MAX-DOAS vertical columns and profiles are used for validating GOME-2 and OMI satellite observations. To characterise the biomass-burning and biogenic emissions in the Bujumbura region, the trace gases and aerosol MAX-DOAS retrievals are used in combination to MODIS fire counts/radiative-power and GOME-2/OMI NO2 and HCHO satellite data, as well as simulations from the NOAA backward trajectory model HYSPLIT. First results show that HCHO seasonal variation around local noon is driven by the alternation of rain and dry periods, the latter being associated with intense biomass-burning agricultural activities and forest fires in the south/south-east and transport from this region to Bujumbura. In contrast, NO2 is seen to depend mainly on local emissions close to the city, due

  12. 1979-1999 satellite total ozone column measurements over West Africa

    Directory of Open Access Journals (Sweden)

    P. Di Carlo

    2000-06-01

    Full Text Available Total Ozone Mapping Spectrometer (TOMS instruments have been flown on NASA/GSFC satellites for over 20 years. They provide near real-time ozone data for Atmospheric Science Research. As part of preliminary efforts aimed to develop a Lidar station in Nigeria for monitoring the atmospheric ozone and aerosol levels, the monthly mean TOMS total column ozone measurements between 1979 to 1999 have been analysed. The trends of the total column ozone showed a spatial and temporal variation with signs of the Quasi Biennial Oscillation (QBO during the 20-year study period. The values of the TOMS total ozone column, over Nigeria (4-14°N is within the range of 230-280 Dobson Units, this is consistent with total ozone column data, measured since April 1993 with a Dobson Spectrophotometer at Lagos (3°21¢E, 6°33¢N, Nigeria.

  13. Tropical intercontinental optical measurement network of aerosol, precipitable water and total column ozone

    Science.gov (United States)

    Holben, B. N.; Tanre, D.; Reagan, J. A.; Eck, T. F.; Setzer, A.; Kaufman, Y. A.; Vermote, E.; Vassiliou, G. D.; Lavenu, F.

    1992-01-01

    A new generation of automatic sunphotometers is used to systematically monitor clear sky total column aerosol concentration and optical properties, precipitable water and total column ozone diurnally and annually in West Africa and South America. The instruments are designed to measure direct beam sun, solar aureole and sky radiances in nine narrow spectral bands from the UV to the near infrared on an hourly basis. The instrumentation and the algorithms required to reduce the data for subsequent analysis are described.

  14. Development of a New Radiation Measuring Instrument for the Column Scanning Technique - NibraS

    International Nuclear Information System (INIS)

    Benahmed, A.; Alami, R.

    2013-06-01

    The radiation measuring instrument, called Nibras, associated to a special data processing software for Column scanning is a new data acquisition system. It was developed to scan and to plot density profiles, inside a distillation column, which illustrates the activity of the radiations able to cross the contents of the column. Nibras is an autonomous data logger with very low power consumption, using only 4 batteries of 1.5 V and can be operated for more than 120 hours continuously; this presents an ecological and economic importance. Another particularity of Nibras consists in its dual functionality to display counting rates indicating the existence and the intensity of radiation; and to perform a real-time control in industrial plant particularly in oil distillation columns, due to its user-friendly software. This last provides essential data to optimize the performance of the columns, extend column run times, track the performance-deteriorating effects of fouling and solids deposition, and to identify maintenance requirements well in advance of scheduled turnarounds. This on-line knowledge can reduce repair downtime significantly. (authors)

  15. Airborne 2-Micron Double-Pulsed Integrated Path Differential Absorption Lidar for Column CO2 Measurement

    Science.gov (United States)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Fay, James J.; Reithmaier, Karl

    2014-01-01

    Double-pulse 2-micron lasers have been demonstrated with energy as high as 600 millijouls and up to 10 Hz repetition rate. The two laser pulses are separated by 200 microseconds and can be tuned and locked separately. Applying double-pulse laser in DIAL system enhances the CO2 measurement capability by increasing the overlap of the sampled volume between the on-line and off-line. To avoid detection complicity, integrated path differential absorption (IPDA) lidar provides higher signal-to-noise ratio measurement compared to conventional range-resolved DIAL. Rather than weak atmospheric scattering returns, IPDA rely on the much stronger hard target returns that is best suited for airborne platforms. In addition, the IPDA technique measures the total integrated column content from the instrument to the hard target but with weighting that can be tuned by the transmitter. Therefore, the transmitter could be tuned to weight the column measurement to the surface for optimum CO2 interaction studies or up to the free troposphere for optimum transport studies. Currently, NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micron IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  16. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    Science.gov (United States)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  17. Measurements of Nitrogen Dioxide Total Column Amounts using a Brewer Double Spectrophotometer in Direct Sun Mode

    Science.gov (United States)

    Cede, Alexander; Herman, Jay; Richter, Andreas; Krotkov, Nickolay; Burrows, John

    2006-01-01

    NO2 column amounts were measured for the past 2 years at Goddard Space Flight Center, Greenbelt, Maryland, using a Brewer spectrometer in direct Sun mode. A new bootstrap method to calibrate the instrument is introduced and described. This technique selects the cleanest days from the database to obtain the solar reference spectrum. The main advantage for direct Sun measurements is that the conversion uncertainty from slant column to vertical column is negligible compared to the standard scattered light observations where it is typically on the order of 100% (2sigma) at polluted sites. The total 2sigma errors of the direct Sun retrieved column amounts decrease with solar zenith angle and are estimated at 0.2 to 0.6 Dobson units (DU, 1 DU approx. equal to 2.7 10(exp 16) molecules cm(exp -2)), which is more accurate than scattered light measurements for high NO2 amounts. Measured NO2 column amounts, ranging from 0 to 3 DU with a mean of 0.7 DU, show a pronounced daily course and a strong variability from day to day. The NO2 concentration typically increases from sunrise to noon. In the afternoon it decreases in summer and stays constant in winter. As expected from the anthropogenic nature of its source, NO2 amounts on weekends are significantly reduced. The measurements were compared to satellite retrievals from Scanning Image Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). Satellite data give the same average NO2 column and show a seasonal cycle that is similar to the ground data in the afternoon. We show that NO2 must be considered when retrieving aerosol absorption properties, especially for situations with low aerosol optical depth.

  18. Comparison of predicted and measured pulsed-column profiles and inventories

    International Nuclear Information System (INIS)

    Ostenak, C.A.; Cermak, A.F.

    1983-01-01

    Nuclear materials accounting and process control in fuels reprocessing plants can be improved by near-real-time estimation of the in-process inventory in solvent-extraction contactors. Experimental studies were conducted on pilot- and plant-scale pulsed columns by Allied-General Nuclear Service (AGNS), and the extensive uranium concentration-profile and inventory data were analyzed by Los Alamos and AGNS to develop and evaluate different predictive inventory techniques. Preliminary comparisons of predicted and measured pulsed-column profiles and inventories show promise for using these predictive techniques to improve nuclear materials accounting and process control in fuels reprocessing plants

  19. Soft x-ray laser gain measurements in a recombining plasma column

    International Nuclear Information System (INIS)

    Suckewer, S.; Skinner, C.H.; Milchberg, H.; Keane, C.; Voorhees, D.

    1985-03-01

    An enhancement of approx. 100 of stimulated emission over spontaneous emission of the CVI 182 A line (one-pass gain approx. = 6.5) was measured in a recombining, magnetically confined plasma column by two independent techniques using intensity calibrated XUV monochromators. Additional confirmation that the enhancement was due to stimulated emission has been obtained with a soft x-ray mirror

  20. A New ENSO Index Derived from Satellite Measurements of Column Ozone

    Science.gov (United States)

    Ziemke, J. R.; Chandra, S.; Oman, L. D.; Bhartia, P. K.

    2010-01-01

    Column Ozone measured in tropical latitudes from Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI) are used to derive an El Nino-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the Ozone ENSO Index (OEI) and is the first developed from atmospheric trace gas measurements. The OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and then taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1K change in Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while a +1 hPa change in SOI coincides with a -1.7DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4DU and -1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

  1. Measurement of electric field distribution along the plasma column in Microwave jet discharges at atmospheric pressure

    International Nuclear Information System (INIS)

    Razzak, M. Abdur; Takamura, Shuichi; Tsujikawa, Takayuki; Shibata, Hideto; Hatakeyama, Yuto

    2009-01-01

    A new technique for the direct measurement of electric field distribution along the plasma column in microwave jet discharges is developed and employed. The technique is based on a servomotor-controlled reciprocating antenna moving along the nozzle axis and plasma column. The measurement technique is applied to a rectangular waveguide-based 2.45 GHz argon and helium plasma jets generated by using the modified TIAGO nozzle at atmospheric pressure with a microwave power of less than 500 W. The measurement has been done with and without igniting the plasma jet in order to investigate the standing wave propagation along the nozzle axis and plasma column. It is observed that the electric field decay occurs slowly in space with plasma ignition than that of without plasma, which indicates the surface electromagnetic wave propagation along the plasma column in order to sustain the plasma jet. This study enables one to design, determine and optimize the size and structure of launcher nozzle, which plays an important role for the stable and efficient microwave plasma generators. (author)

  2. Column CO2 Measurement From an Airborne Solid-State Double-Pulsed 2-Micron Integrated Path Differential Absorption Lidar

    Science.gov (United States)

    Singh, U. N.; Yu, J.; Petros, M.; Refaat, T. F.; Remus, R.; Fay, J.; Reithmaier, K.

    2014-01-01

    NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micrometers IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  3. Measurement of liquid mixing characteristics in large-sized ion exchange column for isotope separation by stepwise response method

    International Nuclear Information System (INIS)

    Fujine, Sachio; Saito, Keiichiro; Iwamoto, Kazumi; Itoi, Toshiaki.

    1981-07-01

    Liquid mixing in a large-sized ion exchange column for isotope separation was measured by the step-wise response method, using NaCl solution as tracer. A 50 cm diameter column was packed with an ion exchange resin of 200 μm in mean diameter. Experiments were carried out for several types of distributor and collector, which were attached to each end of the column. The smallest mixing was observed for the perforated plate type of the collector, coupled with a minimum stagnant volume above the ion exchange resin bed. The 50 cm diameter column exhibited the better characteristics of liquid mixing than the 2 cm diameter column for which the good performance of lithium isotope separation had already been confirmed. These results indicate that a large increment of throughput is attainable by the scale-up of column diameter with the same performance of isotope separation as for the 2 cm diameter column. (author)

  4. Residual diesel measurement in sand columns after surfactant/alcohol washing

    International Nuclear Information System (INIS)

    Martel, R.; Gelinas, P.J.

    1996-01-01

    A new simple gravimetric technique has been designed to determine residual oil saturation of complex hydrocarbon mixtures (e.g., diesel) in sand column experiments because reliable methods are lacking. The He/N 2 technique is based on drying of sand columns by circulating helium gas to drag oil droplets in a cold trap (liquid nitrogen). With this technique, residual diesel measurement can be performed easily immediately after alcohol/surfactant washing and in the same lab. For high residual diesel content in Ottawa sand (25 to 30 g/kg), the technique is much more accurate (± 2% or 600 mg/kg) than the standard analytical methods for the determination of mineral oil and grease. The average relative error on partial diesel dissolution in sand column estimated after alcohol/surfactant flooding (residual saturation of 10 to 15 g/kg) is as low as 5%. The precision of the He/N 2 technique is adequate to compare relative efficiency of washing solutions when partial extraction of residual oil in Ottawa sand columns is performed. However, this technique is not adapted for determination of traces of oil in sediment or for environmental control of contaminated soils. Each diesel determination by the He/N 2 technique costs less than $8 in chemical products (helium and liquid nitrogen). A simple laboratory drying setup can be built for less than $400 which makes this technique valuable for diesel analyses when a large number of tests are required

  5. Fire emissions constrained by the synergistic use of formaldehyde and glyoxal SCIAMACHY columns in a two-compound inverse modelling framework

    Science.gov (United States)

    Stavrakou, T.; Muller, J.; de Smedt, I.; van Roozendael, M.; Vrekoussis, M.; Wittrock, F.; Richter, A.; Burrows, J.

    2008-12-01

    Formaldehyde (HCHO) and glyoxal (CHOCHO) are carbonyls formed in the oxidation of volatile organic compounds (VOCs) emitted by plants, anthropogenic activities, and biomass burning. They are also directly emitted by fires. Although this primary production represents only a small part of the global source for both species, yet it can be locally important during intense fire events. Simultaneous observations of formaldehyde and glyoxal retrieved from the SCIAMACHY satellite instrument in 2005 and provided by the BIRA/IASB and the Bremen group, respectively, are compared with the corresponding columns simulated with the IMAGESv2 global CTM. The chemical mechanism has been optimized with respect to HCHO and CHOCHO production from pyrogenically emitted NMVOCs, based on the Master Chemical Mechanism (MCM) and on an explicit profile for biomass burning emissions. Gas-to-particle conversion of glyoxal in clouds and in aqueous aerosols is considered in the model. In this study we provide top-down estimates for fire emissions of HCHO and CHOCHO precursors by performing a two- compound inversion of emissions using the adjoint of the IMAGES model. The pyrogenic fluxes are optimized at the model resolution. The two-compound inversion offers the advantage that the information gained from measurements of one species constrains the sources of both compounds, due to the existence of common precursors. In a first inversion, only the burnt biomass amounts are optimized. In subsequent simulations, the emission factors for key individual NMVOC compounds are also varied.

  6. Observing atmospheric formaldehyde (HCHO from space: validation and intercomparison of six retrievals from four satellites (OMI, GOME2A, GOME2B, OMPS with SEAC4RS aircraft observations over the southeast US

    Directory of Open Access Journals (Sweden)

    L. Zhu

    2016-11-01

    Full Text Available Formaldehyde (HCHO column data from satellites are widely used as a proxy for emissions of volatile organic compounds (VOCs, but validation of the data has been extremely limited. Here we use highly accurate HCHO aircraft observations from the NASA SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys campaign over the southeast US in August–September 2013 to validate and intercompare six retrievals of HCHO columns from four different satellite instruments (OMI, GOME2A, GOME2B and OMPS; for clarification of these and other abbreviations used in the paper, please refer to Appendix A and three different research groups. The GEOS-Chem chemical transport model is used as a common intercomparison platform. All retrievals feature a HCHO maximum over Arkansas and Louisiana, consistent with the aircraft observations and reflecting high emissions of biogenic isoprene. The retrievals are also interconsistent in their spatial variability over the southeast US (r  =  0.4–0.8 on a 0.5°  ×  0.5°  grid and in their day-to-day variability (r  =  0.5–0.8. However, all retrievals are biased low in the mean by 20–51 %, which would lead to corresponding bias in estimates of isoprene emissions from the satellite data. The smallest bias is for OMI-BIRA, which has high corrected slant columns relative to the other retrievals and low scattering weights in its air mass factor (AMF calculation. OMI-BIRA has systematic error in its assumed vertical HCHO shape profiles for the AMF calculation, and correcting this would eliminate its bias relative to the SEAC4RS data. Our results support the use of satellite HCHO data as a quantitative proxy for isoprene emission after correction of the low mean bias. There is no evident pattern in the bias, suggesting that a uniform correction factor may be applied to the data until better understanding is achieved.

  7. Charge collection measurements in single-type column 3D sensors

    International Nuclear Information System (INIS)

    Scaringella, M.; Polyakov, A.; Sadrozinski, H.F.-W.; Bruzzi, M.; Tosi, C.; Boscardin, M.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.; Dalla Betta, G.-F.

    2007-01-01

    We report on charge collection studies on 3D silicon detectors of single-type column n-diffusions in p-substrate, configured either as strip or as pad detectors. The charge is generated by penetrating beta particles from a 90 Sr source which, together with a scintillation counter, serves as an electron telescope. The charge collection as a function of bias voltage is compared with the depletion thickness derived from the measured C-V characteristics

  8. A new fully automated FTIR system for total column measurements of greenhouse gases

    Directory of Open Access Journals (Sweden)

    M. C. Geibel

    2010-10-01

    Full Text Available This article introduces a new fully automated FTIR system that is part of the Total Carbon Column Observing Network (TCCON. It will provide continuous ground-based measurements of column-averaged volume mixing ratio for CO2, CH4 and several other greenhouse gases in the tropics.

    Housed in a 20-foot shipping container it was developed as a transportable system that could be deployed almost anywhere in the world. We describe the automation concept which relies on three autonomous subsystems and their interaction. Crucial components like a sturdy and reliable solar tracker dome are described in detail. The automation software employs a new approach relying on multiple processes, database logging and web-based remote control.

    First results of total column measurements at Jena, Germany show that the instrument works well and can provide parts of the diurnal as well as seasonal cycle for CO2. Instrument line shape measurements with an HCl cell suggest that the instrument stays well-aligned over several months.

    After a short test campaign for side by side intercomaprison with an existing TCCON instrument in Australia, the system will be transported to its final destination Ascension Island.

  9. A new fully automated FTIR system for total column measurements of greenhouse gases

    Science.gov (United States)

    Geibel, M. C.; Gerbig, C.; Feist, D. G.

    2010-10-01

    This article introduces a new fully automated FTIR system that is part of the Total Carbon Column Observing Network (TCCON). It will provide continuous ground-based measurements of column-averaged volume mixing ratio for CO2, CH4 and several other greenhouse gases in the tropics. Housed in a 20-foot shipping container it was developed as a transportable system that could be deployed almost anywhere in the world. We describe the automation concept which relies on three autonomous subsystems and their interaction. Crucial components like a sturdy and reliable solar tracker dome are described in detail. The automation software employs a new approach relying on multiple processes, database logging and web-based remote control. First results of total column measurements at Jena, Germany show that the instrument works well and can provide parts of the diurnal as well as seasonal cycle for CO2. Instrument line shape measurements with an HCl cell suggest that the instrument stays well-aligned over several months. After a short test campaign for side by side intercomaprison with an existing TCCON instrument in Australia, the system will be transported to its final destination Ascension Island.

  10. Precision Column CO2 Measurement from Space Using Broad Band LIDAR

    Science.gov (United States)

    Heaps, William S.

    2009-01-01

    In order to better understand the budget of carbon dioxide in the Earth's atmosphere it is necessary to develop a global high precision understanding of the carbon dioxide column. To uncover the missing sink" that is responsible for the large discrepancies in the budget as we presently understand it, calculation has indicated that measurement accuracy of 1 ppm is necessary. Because typical column average CO2 has now reached 380 ppm this represents a precision on the order of 0.25% for these column measurements. No species has ever been measured from space at such a precision. In recognition of the importance of understanding the CO2 budget to evaluate its impact on global warming the National Research Council in its decadal survey report to NASA recommended planning for a laser based total CO2 mapping mission in the near future. The extreme measurement accuracy requirements on this mission places very strong constraints on the laser system used for the measurement. This work presents an overview of the characteristics necessary in a laser system used to make this measurement. Consideration is given to the temperature dependence, pressure broadening, and pressure shift of the CO2 lines themselves and how these impact the laser system characteristics. We are examining the possibility of making precise measurements of atmospheric carbon dioxide using a broad band source of radiation. This means that many of the difficulties in wavelength control can be treated in the detector portion of the system rather than the laser source. It also greatly reduces the number of individual lasers required to make a measurement. Simplifications such as these are extremely desirable for systems designed to operate from space.

  11. Miniaturized Laser Heterodyne Radiometer for Measurements of CO2 in the Atmospheric Column

    Science.gov (United States)

    Wilson, E. L.; Mclinden, M. L.; Miller, J. H.; Allan, G. R.; Lott, L. E.; Melroy, H. R.; Clarke, G. B.

    2013-01-01

    We have developed a low-cost, miniaturized laser heterodyne radiometer for highly sensitive measurements of carbon dioxide (CO2) in the atmospheric column. In this passive design, sunlight that has undergone absorption by CO2 in the atmosphere is collected and mixed with continuous wave laser light that is step-scanned across the absorption feature centered at 1,573.6 nm. The resulting radio frequency beat signal is collected as a function of laser wavelength, from which the total column mole fraction can be de-convolved. We are expanding this technique to include methane (CH4) and carbon monoxide (CO), and with minor modifications, this technique can be expanded to include species such as water vapor (H2O) and nitrous oxide (N2O).

  12. Advanced intensity-modulation continuous-wave lidar techniques for ASCENDS CO2 column measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. W.; Obland, Michael D.; Meadows, Byron

    2015-10-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  13. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for ASCENDS O2 Column Measurements

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Meadows, Byron

    2015-01-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  14. Investigation of turbulent swirling jet-flames by PIV / OH PLIF / HCHO PLIF

    Science.gov (United States)

    Lobasov, A. S.; Chikishev, L. M.

    2018-03-01

    The present paper reports on the investigation of fuel-lean and fuel-rich turbulent combustion in a high-swirl jet. Swirl rate of the flow exceeded a critical value for breakdown of the swirling jet’s vortex core and formation of the recirculation zone at the jet axis. The measurements were performed by the stereo PIV, OH PLIF and HCHO PLIF techniques, simultaneously. The Reynolds number based on the flow rate and viscosity of the air was fixed as 5 000 (the bulk velocity was U 0 = 5 m/s). Three cases of the equivalence ratio ϕ of the mixture issuing from the nozzle-burner were considered, viz., 0.7, 1.4 and 2.5. The latter case corresponded to a lifted flame of fuel-rich swirling jet flow, partially premixed with the surrounding air. In all cases the flame front was subjected to deformations due to large-scale vortices, which rolled-up in the inner (around the central recirculation zone) and outer (between the annular jet core and surrounding air) mixing layers.

  15. Using NDACC column measurements of carbonyl sulfide to estimate its sources and sinks

    Science.gov (United States)

    Wang, Yuting; Marshall, Julia; Palm, Mathias; Deutscher, Nicholas; Roedenbeck, Christian; Warneke, Thorsten; Notholt, Justus; Baker, Ian; Berry, Joe; Suntharalingam, Parvadha; Jones, Nicholas; Mahieu, Emmanuel; Lejeune, Bernard; Hannigan, James; Conway, Stephanie; Strong, Kimberly; Campbell, Elliott; Wolf, Adam; Kremser, Stefanie

    2016-04-01

    Carbonyl sulfide (OCS) is taken up by plants during photosynthesis through a similar pathway as carbon dioxide (CO2), but is not emitted by respiration, and thus holds great promise as an additional constraint on the carbon cycle. It might act as a sort of tracer of photosynthesis, a way to separate gross primary productivity (GPP) from the net ecosystem exchange (NEE) that is typically derived from flux modeling. However the estimates of OCS sources and sinks still have significant uncertainties, which make it difficult to use OCS as a photosynthetic tracer, and the existing long-term surface-based measurements are sparse. The NDACC-IRWG measures the absorption of OCS in the atmosphere, and provides a potential long-term database of OCS total/partial columns, which can be used to evaluate OCS fluxes. We have retrieved OCS columns from several NDACC sites around the globe, and compared them to model simulation with OCS land fluxes based on the simple biosphere model (SiB). The disagreement between the measurements and the forward simulations indicates that (1) the OCS land fluxes from SiB are too low in the northern boreal region; (2) the ocean fluxes need to be optimized. A statistical linear flux model describing OCS is developed in the TM3 inversion system, and is used to estimate the OCS fluxes. We performed flux inversions using only NOAA OCS surface measurements as an observational constraint and with both surface and NDACC OCS column measurements, and assessed the differences. The posterior uncertainties of the inverted OCS fluxes decreased with the inclusion of NDACC data comparing to those using surface data only, and could be further reduced if more NDACC sites were included.

  16. Intensity Modulation Techniques for Continuous-Wave Lidar for Column CO2 Measurements

    Science.gov (United States)

    Campbell, J. F.; Lin, B.; Obland, M. D.; Kooi, S. A.; Fan, T. F.; Meadows, B.; Browell, E. V.; Erxleben, W. H.; McGregor, D.; Dobler, J. T.; Pal, S.; O'Dell, C.

    2017-12-01

    Global and regional atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission and the Atmospheric Carbon and Transport (ACT) - America project are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity-Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space and airborne platforms to meet the ASCENDS and ACT-America science measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) and Linear Swept Frequency modulations to uniquely discriminate surface lidar returns from intermediate aerosol and cloud returns. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that take advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques and provides very high (at sub-meter level) range resolution. We compare BPSK to linear swept frequency and introduce a new technique to eliminate sidelobes in situations from linear swept frequency where the SNR is high with results that rival BPSK. We also investigate the effects of non-linear modulators, which can in some circumstances degrade the orthogonality of the waveforms, and show how to avoid this. These techniques are used in a new data processing architecture written in

  17. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for Column CO2 Measurements

    Science.gov (United States)

    Campbell, J. F.; Lin, B.; Obland, M. D.; Liu, Z.; Kooi, S. A.; Fan, T. F.; Nehrir, A. R.; Meadows, B.; Browell, E. V.

    2016-12-01

    Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for Column CO2 MeasurementsJoel F. Campbell1, Bing Lin1, Michael D. Obland1, Zhaoyan Liu1, Susan Kooi2, Tai-Fang Fan2, Amin R. Nehrir1, Byron Meadows1, Edward V. Browell31NASA Langley Research Center, Hampton, VA 23681 2SSAI, NASA Langley Research Center, Hampton, VA 23681 3STARSS-II Affiliate, NASA Langley Research Center, Hampton, VA 23681 AbstractGlobal and regional atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission and the Atmospheric Carbon and Transport (ACT) - America project are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity-Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space and airborne platforms to meet the ASCENDS and ACT-America science measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud returns. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby minimizing bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new sub-meter hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. These techniques are used in a new data processing

  18. Retrieval of the vertical column of an atmospheric constituent from data fusion of remote sensing measurements

    International Nuclear Information System (INIS)

    Ceccherini, Simone; Carli, Bruno; Cortesi, Ugo; Del Bianco, Samuele; Raspollini, Piera

    2010-01-01

    Techniques of data fusion are presently being considered with increasing interest for application to atmospheric observations from space because of their capability to optimally exploit the complementary information provided by different instruments operating aboard on-going and future satellite missions. The task of combining measurements of the same target, when carried out at the level of the retrieved state vectors, faces with two major problems: the need to interpolate the products represented on different retrieval grids which determines a loss of information and the presence of a priori information in the products that can determine a bias in the product of the data fusion. The measurement space solution method avoids these problems. Based on this method we present a novel approach to retrieve the vertical column of an atmospheric constituent from data fusion of remote sensing measurements. We apply the method to retrieve the ozone column from the fusion of simulated measurements of the IASI nadir-viewing spectrometer onboard the METOP-A platform and of the MIPAS limb sounder onboard the ENVISAT satellite. The performance of the method is evaluated in terms of retrieval errors and averaging kernels of the products. The results show the evidence of improved retrieval quality when comparing the outcome of data fusion with that of the inversion process applied to spectra from either of the two instruments.

  19. Miniaturized Laser Heterodyne Radiometer (LHR) for Measurements of Greenhouse Gases in the Atmospheric Column

    Science.gov (United States)

    Steel, Emily; McLinden, Matthew

    2012-01-01

    This passive laser heterodyne radiometer (LHR) instrument simultaneously measures multiple trace gases in the atmospheric column including carbon dioxide (CO2) and methane (CH4), and resolves their concentrations at different altitudes. This instrument has been designed to operate in tandem with the passive aerosol sensor currently used in AERONET (an established network of more than 450 ground aerosol monitoring instruments worldwide). Because aerosols induce a radiative effect that influences terrestrial carbon exchange, simultaneous detection of aerosols with these key carbon cycle gases offers a uniquely comprehensive measurement approach. Laser heterodyne radiometry is a technique for detecting weak signals that was adapted from radio receiver technology. In a radio receiver, a weak input signal from a radio antenna is mixed with a stronger local oscillator signal. The mixed signal (beat note, or intermediate frequency) has a frequency equal to the difference between the input signal and the local oscillator. The intermediate frequency is amplified and sent to a detector that extracts the audio from the signal. In the LHR instrument described here, sunlight that has undergone absorption by the trace gas is mixed with laser light at a frequency matched to a trace gas absorption feature in the infrared (IR). Mixing results in a beat signal in the RF (radio frequency) region that can be related to the atmospheric concentration. For a one-second integration, the estimated column sensitivities are 0.1 ppmv for CO2, and Greenhouse gases Observational SATellite). The only network that currently measures CO2 and CH4 in the atmospheric column is TCCON (Total Carbon Column Observing Network), and only two of its 16 operational sites are in the United States. TCCON data is used for validation of GOSAT data, and will be used for OCO-2 validation. While these Fourier-transform spectrometers (FTS) can measure the largest range of trace gases, the network is severely limited

  20. Influence of plant roots on electrical resistivity measurements of cultivated soil columns

    Science.gov (United States)

    Maloteau, Sophie; Blanchy, Guillaume; Javaux, Mathieu; Garré, Sarah

    2016-04-01

    Electrical resistivity methods have been widely used for the last 40 years in many fields: groundwater investigation, soil and water pollution, engineering application for subsurface surveys, etc. Many factors can influence the electrical resistivity of a media, and thus influence the ERT measurements. Among those factors, it is known that plant roots affect bulk electrical resistivity. However, this impact is not yet well understood. The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil column. For this research, it is assumed that roots system affect the electrical properties of the rhizosphere. Indeed the root activity (by transporting ions, releasing exudates, changing the soil structure,…) will modify the rhizosphere electrical conductivity (Lobet G. et al, 2013). This experiment is included in a bigger research project about the influence of roots system on geophysics measurements. Measurements are made on cylinders of 45 cm high and a diameter of 20 cm, filled with saturated loam on which seeds of Brachypodium distachyon (L.) Beauv. are sowed. Columns are equipped with electrodes, TDR probes and temperature sensors. Experiments are conducted at Gembloux Agro-Bio Tech, in a growing chamber with controlled conditions: temperature of the air is fixed to 20° C, photoperiod is equal to 14 hours, photosynthetically active radiation is equal to 200 μmol m-2s-1, and air relative humidity is fixed to 80 %. Columns are fully saturated the first day of the measurements duration then no more irrigation is done till the end of the experiment. The poster will report the first results analysis of the electrical resistivity distribution in the soil columns through space and time. These results will be discussed according to the plant development and other controlled factors. Water content of the soil will also be detailed

  1. A Broad Bank Lidar for Precise Atmospheric CO2 Column Absorption Measurement from Space

    Science.gov (United States)

    Georgieva, E. M.; Heaps, W. S.; Huang, W.

    2010-01-01

    Accurate global measurement of carbon dioxide column with the aim of discovering and quantifying unknown sources and sinks has been a high priority for the last decade. In order to uncover the "missing sink" that is responsible for the large discrepancies in the budget the critical precision for a measurement from space needs to be on the order of 1 ppm. To better understand the CO2 budget and to evaluate its impact on global warming the National Research Council (NRC) in its recent decadal survey report (NACP) to NASA recommended a laser based total CO2 mapping mission in the near future. That's the goal of Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission - to significantly enhance the understanding of the role of CO2 in the global carbon cycle. Our current goal is to develop an ultra precise, inexpensive new lidar system for column measurements of CO2 changes in the lower atmosphere that uses a Fabry-Perot interferometer based system as the detector portion of the instrument and replaces the narrow band laser commonly used in lidars with a high power broadband source. This approach reduces the number of individual lasers used in the system and considerably reduces the risk of failure. It also tremendously reduces the requirement for wavelength stability in the source putting this responsibility instead on the Fabry- Perot subsystem.

  2. A Miniaturized Laser Heterodyne Radiometer for Greenhouse Gas Measurements in the Atmospheric Column

    Science.gov (United States)

    Steel, Emily Wilson

    2015-01-01

    Laser Heterodyne Radiometry is a technique adapted from radio receiver technology has been used to measure trace gases in the atmosphere since the 1960s.By leveraging advances in the telecommunications industry, it has been possible to miniaturize this technology.The mini-LHR (Miniaturized Laser Heterodyne Radiometer) has been under development at NASA Goddard Space flight Center since 2009. This sun-viewing instrument measures carbon dioxide and methane in the atmospheric column and operates in tandem with an AERONET sun photometer producing a simultaneous measure of aerosols. The mini-LHR has been extensively field tested in a range of locations ranging in the continental US as well as Alaska and Hawaii and now operates autonomously with sensitivities of approximately 0.2 ppmv and approximately10 ppbv, for carbon dioxide and methane respectively, for 10 averaged scans under clear sky conditions.

  3. Synergistic Effect of Nanophotocatalysis and Nonthermal Plasma on the Removal of Indoor HCHO

    Directory of Open Access Journals (Sweden)

    Yuanwei Lu

    2012-01-01

    Full Text Available Photocatalysis is an effective method of air purification at the condition of a higher pollutant concentration. However, its wide application in indoor air cleaning is limited due to the low level of indoor air contaminants. Immobilizing the nanosized TiO2 particles on the surface of activated carbon filter (TiO2/AC film could increase the photocatalytic reaction rate as a local high pollutant concentration can be formed on the surface of TiO2 by the adsorption of AC. However, the pollutant removal still decreased quickly with the increase in flow velocity, which results in a decrease in air treatment capacity. In order to improve the air treatment capacity by the photocatalytic oxidation (PCO method, this paper used formaldehyde (HCHO as a contaminant to study the effect of combination of PCO with nonthermal plasma technology (NTP on the removal of HCHO. The experimental results show that HCHO removal is more effective with line-to-plate electrode discharge reactor; the HCHO removal and the reaction rate can be enhanced and the amount of air that needs to be cleaned can be improved. Meanwhile, the results show that there is the synergistic effect on the indoor air purification by the combination of PCO with NTP.

  4. Six years of total ozone column measurements from SCIAMACHY nadir observations

    Science.gov (United States)

    Lerot, C.; van Roozendael, M.; van Geffen, J.; van Gent, J.; Fayt, C.; Spurr, R.; Lichtenberg, G.; von Bargen, A.

    2009-04-01

    Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR) in the version 4 of the GOME Data Processor (GDP) and in version 3 of the SCIAMACHY Ground Processor (SGP), respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA). We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2-0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

  5. Six years of total ozone column measurements from SCIAMACHY nadir observations

    Directory of Open Access Journals (Sweden)

    G. Lichtenberg

    2009-04-01

    Full Text Available Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR in the version 4 of the GOME Data Processor (GDP and in version 3 of the SCIAMACHY Ground Processor (SGP, respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA. We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2–0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

  6. Nitrogen dioxide column content measurements made from an aircraft between 5 deg and 82 deg N

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, W A

    1984-01-01

    In the first two weeks of May 1981, the research jet of the German Aerospace Research Estlablishment (DFVLR) was charted to fly a meridional section between 5 deg and 82 deg N. A scanning filter photometer, developed at the Max-Planck-Institut fuer Aeronomie to measure column content values of atmospheric ozone and nitrogen dioxide, using ultraviolet and visible absorption techniques, constituted part of the experimental payload for this campaign that was called SIMOC. The vertical NO2 column content above the aircraft, flying at approximately 10 km, was found to decrease rapidly from 6.9 x 10 to the 15th molecules/sq cm to 2.5 x 10 to the 15th molecules/sq cm around 50 deg N and then to increase again north of 75 deg N. A sharp rise in the NO2 content was observed south of the subtropical jet but this could possibly be due to the increased depth of the troposphere above the aircraft in these regions. 8 references.

  7. High-Accuracy Measurements of Total Column Water Vapor From the Orbiting Carbon Observatory-2

    Science.gov (United States)

    Nelson, Robert R.; Crisp, David; Ott, Lesley E.; O'Dell, Christopher W.

    2016-01-01

    Accurate knowledge of the distribution of water vapor in Earth's atmosphere is of critical importance to both weather and climate studies. Here we report on measurements of total column water vapor (TCWV) from hyperspectral observations of near-infrared reflected sunlight over land and ocean surfaces from the Orbiting Carbon Observatory-2 (OCO-2). These measurements are an ancillary product of the retrieval algorithm used to measure atmospheric carbon dioxide concentrations, with information coming from three highly resolved spectral bands. Comparisons to high-accuracy validation data, including ground-based GPS and microwave radiometer data, demonstrate that OCO-2 TCWV measurements have maximum root-mean-square deviations of 0.9-1.3mm. Our results indicate that OCO-2 is the first space-based sensor to accurately and precisely measure the two most important greenhouse gases, water vapor and carbon dioxide, at high spatial resolution [1.3 x 2.3 km(exp. 2)] and that OCO-2 TCWV measurements may be useful in improving numerical weather predictions and reanalysis products.

  8. An instrumented implant for vertebral body replacement that measures loads in the anterior spinal column.

    Science.gov (United States)

    Rohlmann, Antonius; Gabel, Udo; Graichen, Friedmar; Bender, Alwina; Bergmann, Georg

    2007-06-01

    Realistic loads on a spinal implant are required among others for optimization of implant design and preclinical testing. In addition, such data may help to choose the optimal physiotherapy program for patients with such an implant and to evaluate the efficacy of aids like braces or crutches. Presently, no implant is available that can measure loads in the anterior spinal column during activities of daily life. Therefore, an implant instrumented for in vivo load measurement was developed for vertebral body replacement. The aim of this paper is to describe in detail a telemeterized implant that measures forces and moments acting on it. Six load sensors, a nine-channel telemetry unit and a coil for inductive power supply of the electronic circuits were integrated into a modified vertebral body replacement (Synex). The instrumented part of the implant is hermetically sealed. Patients are videotaped during measurements, and implant loads are displayed on and off line. The average accuracy of load measurement is better than 2% for force and 5% for moment components with reference to the maximum value of 3000 N and 20 Nm, respectively. The measuring implant described here will provide additional information on spinal loads.

  9. Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aiken, Allison [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, Larry K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Andrew [Aerodyne Research, Inc., Billerica, MA (United States); Gorkowski, Kyle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-01

    We deployed Aerodyne Research Inc.’s first Cavity Attenuated Phase Shift extinction (CAPS PMex) monitor (built by Aerodyne) that measures light extinction by using a visible-light-emitting diode (LED) as a light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector in Cape Cod in 2012/13 for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Two-Column Aerosol Project (TCAP). The efficacy of this instrument is based on the fact that aerosols are broadband scatterers and absorbers of light. The input LED is square-wave modulated and passed through the sample cell that distorts it due to exponential decay by aerosol light absorption and scattering; this is measured at the detector. The amount of phase shift of the light at the detector is used to determine the light extinction. This extinction measurement provides an absolute value, requiring no calibration. The goal was to compare the CAPS performance with direct measurements of absorption with ARM’s baseline photoacoustic soot spectrometer (PASS-3) and nephelometer instruments to evaluate its performance.

  10. MAX-DOAS measurements of NO2 column densities in Vienna

    Science.gov (United States)

    Schreier, Stefan; Weihs, Philipp; Peters, Enno; Richter, Andreas; Ostendorf, Mareike; Schönhardt, Anja; Burrows, John P.; Schmalwieser, Alois

    2017-04-01

    In the VINDOBONA (VIenna horizontal aNd vertical Distribution OBservations Of Nitrogen dioxide and Aerosols) project, two Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) systems will be set up at two different locations and altitudes in Vienna, Austria. After comparison measurements in Bremen, Germany, and Cabauw, The Netherlands, the first of the two MAX-DOAS instruments was set up at the University of Veterinary Medicine in the northeastern part of Vienna in December 2016. The instrument performs spectral measurements of visible scattered sunlight at defined horizontal and vertical viewing directions. From these measurements, column densities of NO2 and aerosols are derived by applying the DOAS analysis. First preliminary results are presented. The second MAX-DOAS instrument will be set up in April/May 2017 at the University of Natural Resources and Life Sciences in the northwestern part of Vienna. Once these two instruments are measuring simultaneously, small campaigns including car DOAS zenith-sky and tower DOAS off-axis measurements are planned. The main emphasis of this project will be on the installation and operation of two MAX-DOAS instruments, the improvement of tropospheric NO2 and aerosol retrieval, and the characterization of the horizontal, vertical, and temporal variations of tropospheric NO2 and aerosols in Vienna, Austria.

  11. An inexpensive and stable LED Sun photometer for measuring the water vapor column over South Texas from 1990 to 2001

    Science.gov (United States)

    Mims, Forrest M.

    2002-07-01

    A Sun photometer that uses near-infrared light-emitting diodes (LEDs) as spectrally-selective photodetectors has measured total column water vapor in South Texas since February 1990. The 12 years of solar noon observations to date are correlated with upper air soundings at Del Rio, Texas (r2 = 0.75), and highly correlated with measurements by a Microtops II filter Sun photometer (r2 = 0.94). LEDs are inexpensive and have far better long term stability than the interference filters in conventional Sun photometers. The LED Sun photometer therefore provides an inexpensive, stable and portable means for measuring column water vapor.

  12. Comparison of GOME tropospheric NO2 columns with NO2 profiles deduced from ground-based in situ measurements

    Science.gov (United States)

    Schaub, D.; Boersma, K. F.; Kaiser, J. W.; Weiss, A. K.; Folini, D.; Eskes, H. J.; Buchmann, B.

    2006-08-01

    Nitrogen dioxide (NO2) vertical tropospheric column densities (VTCs) retrieved from the Global Ozone Monitoring Experiment (GOME) are compared to coincident ground-based tropospheric NO2 columns. The ground-based columns are deduced from in situ measurements at different altitudes in the Alps for 1997 to June 2003, yielding a unique long-term comparison of GOME NO2 VTC data retrieved by a collaboration of KNMI (Royal Netherlands Meteorological Institute) and BIRA/IASB (Belgian Institute for Space Aeronomy) with independently derived tropospheric NO2 profiles. A first comparison relates the GOME retrieved tropospheric columns to the tropospheric columns obtained by integrating the ground-based NO2 measurements. For a second comparison, the tropospheric profiles constructed from the ground-based measurements are first multiplied with the averaging kernel (AK) of the GOME retrieval. The second approach makes the comparison independent from the a priori NO2 profile used in the GOME retrieval. This allows splitting the total difference between the column data sets into two contributions: one that is due to differences between the a priori and the ground-based NO2 profile shapes, and another that can be attributed to uncertainties in both the remaining retrieval parameters (such as, e.g., surface albedo or aerosol concentration) and the ground-based in situ NO2 profiles. For anticyclonic clear sky conditions the comparison indicates a good agreement between the columns (n=157, R=0.70/0.74 for the first/second comparison approach, respectively). The mean relative difference (with respect to the ground-based columns) is -7% with a standard deviation of 40% and GOME on average slightly underestimating the ground-based columns. Both data sets show a similar seasonal behaviour with a distinct maximum of spring NO2 VTCs. Further analysis indicates small GOME columns being systematically smaller than the ground-based ones. The influence of different shapes in the a priori and

  13. Comparison of GOME tropospheric NO2 columns with NO2 profiles deduced from ground-based in situ measurements

    Directory of Open Access Journals (Sweden)

    D. Schaub

    2006-01-01

    Full Text Available Nitrogen dioxide (NO2 vertical tropospheric column densities (VTCs retrieved from the Global Ozone Monitoring Experiment (GOME are compared to coincident ground-based tropospheric NO2 columns. The ground-based columns are deduced from in situ measurements at different altitudes in the Alps for 1997 to June 2003, yielding a unique long-term comparison of GOME NO2 VTC data retrieved by a collaboration of KNMI (Royal Netherlands Meteorological Institute and BIRA/IASB (Belgian Institute for Space Aeronomy with independently derived tropospheric NO2 profiles. A first comparison relates the GOME retrieved tropospheric columns to the tropospheric columns obtained by integrating the ground-based NO2 measurements. For a second comparison, the tropospheric profiles constructed from the ground-based measurements are first multiplied with the averaging kernel (AK of the GOME retrieval. The second approach makes the comparison independent from the a priori NO2 profile used in the GOME retrieval. This allows splitting the total difference between the column data sets into two contributions: one that is due to differences between the a priori and the ground-based NO2 profile shapes, and another that can be attributed to uncertainties in both the remaining retrieval parameters (such as, e.g., surface albedo or aerosol concentration and the ground-based in situ NO2 profiles. For anticyclonic clear sky conditions the comparison indicates a good agreement between the columns (n=157, R=0.70/0.74 for the first/second comparison approach, respectively. The mean relative difference (with respect to the ground-based columns is −7% with a standard deviation of 40% and GOME on average slightly underestimating the ground-based columns. Both data sets show a similar seasonal behaviour with a distinct maximum of spring NO2 VTCs. Further analysis indicates small GOME columns being systematically smaller than the ground-based ones. The influence of different shapes in the a

  14. Calibration of column-averaged CH4 over European TCCON FTS sites with airborne in-situ measurements

    NARCIS (Netherlands)

    Geibel, M. C.; Messerschmidt, J.; Gerbig, C.; Blumenstock, T.; Chen, H.; Hase, F.; Kolle, O.; Lavric, J. V.; Notholt, J.; Palm, M.; Rettinger, M.; Schmidt, Martina; Sussmann, R.; Warneke, T.; Feist, D. G.

    2012-01-01

    In September/October 2009, six European ground-based Fourier Transform Spectrometers (FTS) of the Total Carbon Column Observation Network (TCCON) were calibrated for the first time using aircraft measurements. The campaign was part of the Infrastructure for Measurement of the European Carbon Cycle

  15. Remotely operable compact instruments for measuring atmospheric CO2 and CH4 column densities at surface monitoring sites

    Directory of Open Access Journals (Sweden)

    I. Morino

    2010-08-01

    Full Text Available Remotely operable compact instruments for measuring atmospheric CO2 and CH4 column densities were developed in two independent systems: one utilizing a grating-based desktop optical spectrum analyzer (OSA with a resolution enough to resolve rotational lines of CO2 and CH4 in the regions of 1565–1585 and 1674–1682 nm, respectively; the other is an application of an optical fiber Fabry-Perot interferometer (FFPI to obtain the CO2 column density. Direct sunlight was collimated via a small telescope installed on a portable sun tracker and then transmitted through an optical fiber into the OSA or the FFPI for optical analysis. The near infrared spectra of the OSA were retrieved by a least squares spectral fitting algorithm. The CO2 and CH4 column densities deduced were in excellent agreement with those measured by a Fourier transform spectrometer with high resolution. The rovibronic lines in the wavelength region of 1570–1575 nm were analyzed by the FFPI. The I0 and I values in the Beer-Lambert law equation to obtain CO2 column density were deduced by modulating temperature of the FFPI, which offered column CO2 with the statistical error less than 0.2% for six hours measurement.

  16. The Utility of the OMI HCHO/NO2 in Air Quality Decision-Making Activities

    Science.gov (United States)

    Duncan, Bryan

    2010-01-01

    I will discuss a novel and practical application of the OMI HCHU and NO2 data products to the "weight of evidence" in the air quality decision-making process (e.g., State Implementation Plan (SIP)) for a city, region, or state to demonstrate that it is making progress toward attainment of the National Ambient Air Quality Standard (NAAQS) for ozone. Any trend, or lack thereof, in the observed OMI HCHO/NO2 may support that an emission control strategy implemented to reduce ozone is or is not occurring for a metropolitan area. In addition, the observed OMI HCHO/NO2 may be used to define new emission control strategies as the photochemical environments of urban areas evolve over time. I will demonstrate the utility of the OMI HCHO/NO2 over the U.S. for air quality applications with support from simulations with both a regional model and a photochemical box model. These results support mission planning of an OMI-like instrument for the proposed GEO-CAPE satellite that has as one of its objectives to study air quality from space. However, I'm attending the meeting as the Aura Deputy Project Scientist, so I don't technically need to present anything to justify the travel.

  17. Measuring Total Column Water Vapor by Pointing an Infrared Thermometer at the Sky

    Science.gov (United States)

    Mims, Forrest M., III; Chambers, Lin H.; Brooks, David R.

    2011-01-01

    A 2-year study affirms that the temperature (Tz) indicated by an inexpensive ($20 to $60) IR thermometer pointed at the cloud-free zenith sky provides an approximate indication of the total column water vapor (precipitable water or PW). PW was measured by a MICROTOPS II sun photometer. The coefficient of correlation (r2) of the PW and Tz was 0.90, and the rms difference was 3.2 mm. A comparison of the Tz data with the PW provided by a GPS site 31 km NNE yielded an r2 of 0.79, and an rms difference of 5.8 mm. An expanded study compared Tz from eight IR thermometers with PW at various times during the day and night from 17 May to 18 October 2010, mainly at the Texas site and 10 days at Hawaii's Mauna Loa Observatory (MLO). The best results of this comparison were provided by two IR thermometers models that yielded an r2 of 0.96 and an rms difference with the PW of 2.7 mm. The results of both the ongoing 2-year study and the 5-month instrument comparison show that IR thermometers can measure PW with an accuracy (rms difference/mean PW) approaching 10%, the accuracy typically ascribed to sun photometers.

  18. Accurate measurements of infinite dilution activity coefficients using gas chromatography with static-wall-coated open-tubular columns.

    Science.gov (United States)

    Xu, Qianqian; Su, Baogen; Luo, Xinyi; Xing, Huabin; Bao, Zongbi; Yang, Qiwei; Yang, Yiwen; Ren, Qilong

    2012-11-06

    Wall-coated open-tubular (WCOT) columns provide higher column efficiency and lower solute interfacial adsorption effect than packed columns. However, previous efforts used to measure the infinite dilution activity coefficient (γ(∞)) via a chromatographic technique have used packed columns, because the low carrier gas flow rate (U) and the small stationary phase amount (n(2)) in WCOT columns raise large errors. By rationally revising the γ(∞)-calculation equation for static-wall-coated open-tubular column, we observed that U and n(2) are not necessarily needed and the resulting error could be reduced, and WCOT column gas chromatography subsequently became a superior method for the accurate γ(∞) determination. In this study, we validate our revised γ(∞)-calculation equation by measuring γ(∞) in an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate system, in which 55 organic compounds covering a wide range of functional groups were used as probe solutes and their γ(∞) values in the ionic liquid were determined at 40.0, 50.0, and 60.0 °C. Experimental error analysis shows that our revised equation remarkably reduces the error compared to the common γ(∞)-calculation equation. Our data is consistent with previously reported values obtained via other techniques, which further proves the credibility of our revised equation. The accurately determined γ(∞) values can be directly used to calculate the partial molar excess enthalpy, selectivity, and capacity, which will benefit for the rapid screening of solvents (especially ionic liquids) in separation approaches.

  19. Neutron flux measurement in the thermal column of the Malaysian TRIGA mark II reactor with MCNP verification

    International Nuclear Information System (INIS)

    Abdel Munem, E.; Shukri, A.; Tajuddin, A.A.

    2006-01-01

    A study of the thermal column of the Malaysian TRIGA Mark II reactor, forming part of a feasibility study for BNCT was proposed in 2001. In the current study, pure metals were used to measure the neutron flux at selected points in the thermal column and the neutron flux determined using SAND-II. Monte Carlo simulation of the thermal column was also carried out. The reactor core was homogenized and calculations of the neutron flux through the graphite stringers performed using MCNP5. The results show good agreement between the measured flux and the MCNP calculated flux. An obvious extension from this is that the MCNP neutron flux output can be utilized as an input spectrum for SAND-II for the flux iteration. (author)

  20. Stiff Columns as Liquefaction Mitigation Measure for Retrofit of Existing Buildings

    Directory of Open Access Journals (Sweden)

    Zaheer Ahmed Almani

    2012-10-01

    Full Text Available In this paper, ground reinforcement with jet grouted columns under shallow foundations of existing buildings was analysed using numerical modelling. This study is related with ground reinforcement by installing stiff jet grouted columns around the shallow foundations of existing building when the foundation soil is liquefied during an earthquake. The isolated shallow square footing pad supporting a typical simple frame structure was constructed on the reinforced ground with stiff jet grouted column rows at the shallow depth from the ground surface. This soil-structure system was modelled and analyzed as plane-strain using the FLAC (Fast Lagrangian Analysis of Continua 2D dynamic modelling and analysis software. The results showed that liquefaction-induced large settlement of shallow foundation of existing building can be reduced to tolerable limits by applying ground reinforcement with continuous rows vertical jet grouted columns adjacent to footing pad.

  1. Ion Chromatographic Method with Post-Column Fuchsin Reaction for Measurement of Bromate in Chlorinated Water

    Directory of Open Access Journals (Sweden)

    Homer C. Genuino

    2009-06-01

    Full Text Available An ion chromatographic method that employs a post-column reaction with fuchsin and spectrophotometric detection was optimized for measuring bromate (BrO3- in water. BrO3- is converted to Br2 by sodium metabisulfite and then reacted with acidic fuchsin to form a red-colored product that strongly absorbs at 530 nm. The reaction of BrO3- and fuchsin reagent is optimum at pH 3.5 and 65 oC. The method has a limit of quantitation of 4.5 µg L-1 and is linear up to 150 µg L-1 BrO3-. Recoveries from spiked samples were high ranging from 95 to 102 % using external standard calibration and 87 to 103 % using standard addition method. Intra-batch and inter-batch reproducibility studies of the method resulted to RSD values ranging from 0.62 to 2.01 % and percent relative error of 0.12 to 2.94 % for BrO3- concentrations of 10 µg L-1 and 50 µg L-1. This method is free of interferences from common inorganic anions at levels typically found in chlorinated tap drinking water without preconcentration. The optimized method can be applied to trace analysis of bromate in chlorinated tap drinking water samples.

  2. Single-column data assimilation for the Atmospheric Radiation Measurement (ARM) Program

    International Nuclear Information System (INIS)

    Louis, J.F.

    1994-01-01

    The main purpose of the ARM program is to provide the necessary data to develop, test and validate the parameterization of clouds and of their interactions with the radiation field, and the computation of radiative transfer in climate models. For various reasons, much of the ARM observations will be imperfect, incomplete, redundant, indirect and unrepresentative. Various techniques of data assimilation have been developed to deal with these problems. The variational data assimilation and adjoint method applied to a single column model is described here. A model is used to simulate the evolution of the atmosphere during an assimilation period. As the model is run, a cost function is computed which is essentially a measure of simulation errors. The method then consists in adjusting some model parameters to minimize the cost function. Optimization of the model parameters needs to be done with a much longer series of data, to cover different meteorological situations. Once parameters are set, nudging terms are used as control variables. The Derber nudging method will require considerable tuning, especially in defining the vertical profiles of the nudging terms. Extensive tests are currently underway of both model optimization and data assimilation

  3. Assessment of MFLL column CO2 measurements obtained during the ACT-America field campaigns

    Science.gov (United States)

    Lin, B.; Browell, E. V.; Kooi, S. A.; Dobler, J. T.; Campbell, J.; Fan, T. F.; Pal, S.; O'Dell, C. W.; Obland, M. D.; Erxleben, W. H.; McGregor, D.; Kochanov, R. V.; DiGangi, J. P.; Davis, K. J.; Choi, Y.

    2017-12-01

    Accurate observations of atmospheric CO2 with airborne and space-based lidar systems such as those used during the Atmospheric Carbon and Transport - America (ACT-America) field campaigns and proposed for the NASA ASCENDS mission would improve our knowledge of CO2 distributions and variations on both regional and global scales, reduce the uncertainties in atmospheric CO2 transport and fluxes, and increase confidence in predictions of future climate changes. To reach these scientific goals, atmospheric column CO2 (XCO2) measurements of the Harris Corporation's Multifunctional Fiber Laser Lidar (MFLL) obtained during the first two ACT-America flight campaigns have been thoroughly investigated by the ACT-America lidar measurement group. MFLL is an intensity-modulated continuous-wave lidar operating in the 1.57-mm CO2 absorption band. Atmospheric XCO2 amounts are retrieved based on the integrated path differential absorption of the lidar signals at online and offline wavelengths between the aircraft and the ground. NASA Langley Research Center and Harris have been collaborating in the development and evaluation of this CO2 lidar approach for a number of years. To gain insights into the lidar performance, the measurement group has collected all possible lidar measurements with corresponding in-situ atmospheric profile information from the first two ACT-America field campaigns, including the data from several flight legs dedicated to lidar calibration. Initially large differences (-1 to 2 %) were found between lidar measured CO2 optical depths and those derived from in-situ observations and spectroscopy from HITRAN2008. When an improved spectroscopic model (Pre-HITRAN2016) was applied, the large systematic errors were much more consistent leading to the development of an empirical linear correction of measured optical depth based on the calibration flight data. This correction accounts for remaining uncertainties in spectroscopic models, environmental conditions, such as

  4. Investigation of the role of the calvin cycle and C1 metabolism during HCHO metabolism in gaseous HCHO-treated petunia under light and dark conditions using 13C-NMR.

    Science.gov (United States)

    Sun, Huiqun; Zhang, Wei; Tang, Lijuan; Han, Shuang; Wang, Xinjia; Zhou, Shengen; Li, Kunzhi; Chen, Limei

    2015-01-01

    It has been shown that formaldehyde (HCHO) absorbed by plants can be assimilated through the Calvin cycle or C1 metabolism. Our previous study indicated that Petunia hybrida could effectively eliminate HCHO from HCHO-polluted air. To understand the roles of C1 metabolism and the Calvin cycle during HCHO metabolism and detoxification in petunia plants treated with gaseous H(13)CHO under light and dark conditions. Aseptically grown petunia plants were treated with gaseous H(13)CHO under dark and light conditions. The metabolites generated from HCHO detoxification in petunia were investigated using (13)C-NMR. [2-(13)C]glycine (Gly) was generated via C1 metabolism and [U-(13)C]glucose (Gluc) was produced through the Calvin cycle simultaneously in petunia treated with low-level gaseous H(13)CHO under light conditions. Generation of [2-(13)C]Gly decreased whereas [U-(13) C]Gluc and [U-(13)C]fructose (Fruc) production increased greatly under high-level gaseous H(13)CHO stress in the light. In contrast, [U-(13)C]Gluc and [U-(13)C] Fruc production decreased greatly and [2-(13)C]Gly generation increased significantly under low-level and high-level gaseous H(13)CHO stress in the dark. C1 metabolism and the Calvin cycle contributed differently to HCHO metabolism and detoxification in gaseous H(13CHO-treated petunia plants. As the level of gaseous HCHO increased, the role of C1 metabolism decreased and the role of the Calvin cycle increased under light conditions. However, opposite changes were observed in petunia plants under dark conditions. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Impact of measurement approach on the quality of gamma scanning density profile in a tray type lab-scale column

    International Nuclear Information System (INIS)

    Shahabinejad, H.; Feghhi, S.A.H.; Khorsandi, M.

    2014-01-01

    This article presents a study for investigating impact of the measurement approach on the quality of gamma scanning density profile in tray type columns using experimental and computational evaluations. Experimental density profiles from the total and the photopeak count measurements, as two approaches in gamma ray column scanning technique, has been compared with the computational density profile from Monte Carlo simulation results. We used a laboratory distillation column of 51 cm diameter as an illustrative example for this investigation. 137 Cs was used as a gamma ray source with the activity of 296 MBq (8 mCi), with a NaI(Tl) detector. MCNP4C Monte Carlo code has been used for simulations. The quality of the density profile in the photopeak count approach is relatively within 155–204% better than that of the total count approach for experimental results. The same comparison for simulation results leads to a relative difference within 100–135% for the density profile. - Highlights: • The quality of density profile in gamma scanning technique has been studied. • Quality of density profile depends on the measurement approach. • A laboratory distillation column has been used as an illustrative example. • MCNP4C Monte Carlo code has been used for simulations

  6. C1 metabolism plays an important role during formaldehyde metabolism and detoxification in petunia under liquid HCHO stress.

    Science.gov (United States)

    Zhang, Wei; Tang, Lijuan; Sun, Huiqun; Han, Shuang; Wang, Xinjia; Zhou, Shengen; Li, Kunzhi; Chen, Limei

    2014-10-01

    Petunia hybrida is a model ornamental plant grown worldwide. To understand the HCHO-uptake efficiency and metabolic mechanism of petunia, the aseptic petunia plants were treated in HCHO solutions. An analysis of HCHO-uptake showed that petunia plants effectively removed HCHO from 2, 4 and 6 mM HCHO solutions. The (13)C NMR analyses indicated that H(13)CHO was primarily used to synthesize [5-(13)C]methionine (Met) via C1 metabolism in petunia plants treated with 2 mM H(13)CHO. Pretreatment with cyclosporin A (CSA) or l-carnitine (LC), the inhibitors of mitochondrial permeability transition pores, did not affect the synthesis of [5-(13)C]Met in petunia plants under 2 mM H(13)CHO stress, indicating that the Met-generated pathway may function in the cytoplasm. Under 4 or 6 mM liquid H(13)CHO stress, H(13)CHO metabolism in petunia plants produced considerable amount of H(13)COOH and [2-(13)C]glycine (Gly) through C1 metabolism and a small amount of [U-(13)C]Gluc via the Calvin Cycle. Pretreatment with CSA or LC significantly inhibited the production of [2-(13)C]Gly in 6 mM H(13)CHO-treated petunia plants, which suggests that chloroplasts and peroxisomes might be involved in the generation of [2-(13)C]Gly. These results revealed that the C1 metabolism played an important role, whereas the Calvin Cycle had only a small contribution during HCHO metabolism and detoxification in petunia under liquid HCHO stress. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Parameters measurement for the thermal neutron beam in the thermal column hole of Xi’an pulse reactor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The distribution of the neutron spectra in the thermal column hole of Xi’an pulse reactor was measured with the time-of-flight method.Compared with the thermal Maxwellian theory neutron spectra,the thermal neutron spectra measured is a little softer,and the average neutron energy of the experimental spectra is about 0.042±0.01 eV.The thermal neutron fluence rate at the front end of thermal column hole,measured with gold foil activation techniques,is about 1.18×105 cm-2 s-1.The standard uncertainty of the measured thermal neutron fluence is about 3%.The spectra-averaged cross section of 197Au(n,γ) determined by the experimental thermal neutron spectra is(92.8±0.93) ×10-24 cm2.

  8. Measurement of bromate in bread by liquid chromatography with post-column flow reactor detection.

    Science.gov (United States)

    Himata, K; Noda, M; Ando, S; Yamada, Y

    2000-01-01

    This method is suitable for the determination of bromate residues in a variety of baked goods. The peer-verified method trial was performed on white bread, multigrain bread, and coffee cake spiked with known levels of potassium bromate. The analytical portion is extracted with deionized water to remove bromate from the bulk of the baked product. The aqueous extract is carried through a series of steps to remove co-extractives that would interfere with the liquid chromatography (LC) in the determinative step or hasten the deterioration of the LC column. The extract is filtered before passing it through a reversed-phase solid-phase extraction (SPE) column and a cation-exchange column in the silver form to remove lipids and chloride, respectively. Ultrafiltration is then used to remove proteins with molecular weights of >30,000 daltons. Finally, a cation-exchange column in the sodium form is used to remove silver ions from the extract. The determinative step uses LC with a reversed-phase column and an ion-pairing agent in the mobile phase. Detection is based on the post-column reaction of bromate with o-dianisidine to form an oxidation product that is quantitated spectrophotometrically at 450 nm. Overall agreement between the submitting and peer laboratories was quite good. For bromate levels of 10-52 ppb, overall mean recoveries were 76.9 and 78.8% for the submitting and peer laboratories, respectively. The standard deviations were higher for the results of the peer laboratory, probably because of the generally higher level of baseline noise present in the chromatograms. The results demonstrate that the method provides adequate accuracy with low-fat as well as high-fat foods. Bromate at levels as low as 5 ppb (ng/g) can be detected with the method.

  9. Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2015-01-01

    A non-thermal gliding arc discharge was generated at atmospheric pressure in an air flow. The dynamics of the plasma column and tracer particles were recorded using two synchronized high-speed cameras. Whereas the data analysis for such systems has previously been performed in 2D (analyzing......, gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius...

  10. Airborne Measurements of CO2 Column Concentration and Range Using a Pulsed Direct-Detection IPDA Lidar

    Science.gov (United States)

    Abshire, James B.; Ramanathan, Anand; Riris, Haris; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Weaver, Clark J.; Browell, Edward V.

    2013-01-01

    We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The lidar measures the atmospheric backscatter profiles and samples the shape of the 1,572.33 nm CO2 absorption line. We participated in the ASCENDS science flights on the NASA DC-8 aircraft during August 2011 and report here lidar measurements made on four flights over a variety of surface and cloud conditions near the US. These included over a stratus cloud deck over the Pacific Ocean, to a dry lake bed surrounded by mountains in Nevada, to a desert area with a coal-fired power plant, and from the Rocky Mountains to Iowa, with segments with both cumulus and cirrus clouds. Most flights were to altitudes >12 km and had 5-6 altitude steps. Analyses show the retrievals of lidar range, CO2 column absorption, and CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds, between cumulus clouds, and to stratus cloud tops. The retrievals shows the decrease in column CO2 due to growing vegetation when flying over Iowa cropland as well as a sudden increase in CO2 concentration near a coal-fired power plant. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption lineshape (averaged for 50 s) matched the predicted shapes to better than 1% RMS error. For 10 s averaging, the scatter in the retrievals was typically 2-3 ppm and was limited by the received signal photon count. Retrievals were made using atmospheric parameters from both an atmospheric model and from in situ temperature and pressure from the aircraft. The retrievals had no free parameters and did not use empirical adjustments, and >70% of the measurements passed screening and were used in analysis. The differences between the lidar-measured retrievals and in situ measured average CO2 column concentrations were 6 km.

  11. Measurement of atmospheric CO2 column concentrations to cloud tops with a pulsed multi-wavelength airborne lidar

    Science.gov (United States)

    Mao, Jianping; Ramanathan, Anand; Abshire, James B.; Kawa, Stephan R.; Riris, Haris; Allan, Graham R.; Rodriguez, Michael; Hasselbrack, William E.; Sun, Xiaoli; Numata, Kenji; Chen, Jeff; Choi, Yonghoon; Yang, Mei Ying Melissa

    2018-01-01

    We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multi-wavelength integrated-path differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up to 13 km during the 2011, 2013 and 2014 NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) science campaigns flown in the United States West and Midwest and were compared to those from an in situ sensor. Analysis of the lidar backscatter profiles shows the average cloud top reflectance was ˜ 5 % for the CO2 measurement at 1572.335 nm except to cirrus clouds, which had lower reflectance. The energies for 1 µs wide laser pulses reflected from cloud tops were sufficient to allow clear identification of CO2 absorption line shape and then to allow retrievals of atmospheric column CO2 from the aircraft to cloud tops more than 90 % of the time. Retrievals from the CO2 measurements to cloud tops had minimal bias but larger standard deviations when compared to those made to the ground, depending on cloud top roughness and reflectance. The measurements show this new capability helps resolve CO2 horizontal and vertical gradients in the atmosphere. When used with nearby full-column measurements to ground, the CO2 measurements to cloud tops can be used to estimate the partial-column CO2 concentration below clouds, which should lead to better estimates of surface carbon sources and sinks. This additional capability of the range-resolved CO2 IPDA lidar technique provides a new benefit for studying the carbon cycle in future airborne and space-based CO2 missions.

  12. Measurement of Atmospheric CO2 Column Concentrations to Cloud Tops With a Pulsed Multi-Wavelength Airborne Lidar

    Science.gov (United States)

    Mao, Jianping; Ramanathan, Anand; Abshire, James B.; Kawa, Stephan R.; Riris, Haris; Allan, Graham R.; Rodriguez, Michael R.; Hasselbrack, William E.; Sun, Xiaoli; Numata, Kenji; hide

    2018-01-01

    We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multi-wavelength integrated-path differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up to 13 km during the 2011, 2013 and 2014 NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) science campaigns flown in the United States West and Midwest and were compared to those from an in situ sensor. Analysis of the lidar backscatter profiles shows the average cloud top reflectance was approx. 5% for the CO2 measurement at 1572.335 nm except to cirrus clouds, which had lower reflectance. The energies for 1 micro-s wide laser pulses reflected from cloud tops were sufficient to allow clear identification of CO2 absorption line shape and then to allow retrievals of atmospheric column CO2 from the aircraft to cloud tops more than 90% of the time. Retrievals from the CO2 measurements to cloud tops had minimal bias but larger standard deviations when compared to those made to the ground, depending on cloud top roughness and reflectance. The measurements show this new capability helps resolve CO2 horizontal and vertical gradients in the atmosphere. When used with nearby full-column measurements to ground, the CO2 measurements to cloud tops can be used to estimate the partial-column CO2 concentration below clouds, which should lead to better estimates of surface carbon sources and sinks. This additional capability of the range-resolved CO2 IPDA lidar technique provides a new benefit for studying the carbon cycle in future airborne and space-based CO2 missions.

  13. Measurement of atmospheric CO2 column concentrations to cloud tops with a pulsed multi-wavelength airborne lidar

    Directory of Open Access Journals (Sweden)

    J. Mao

    2018-01-01

    Full Text Available We have measured the column-averaged atmospheric CO2 mixing ratio to a variety of cloud tops by using an airborne pulsed multi-wavelength integrated-path differential absorption (IPDA lidar. Airborne measurements were made at altitudes up to 13 km during the 2011, 2013 and 2014 NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS science campaigns flown in the United States West and Midwest and were compared to those from an in situ sensor. Analysis of the lidar backscatter profiles shows the average cloud top reflectance was ∼ 5 % for the CO2 measurement at 1572.335 nm except to cirrus clouds, which had lower reflectance. The energies for 1 µs wide laser pulses reflected from cloud tops were sufficient to allow clear identification of CO2 absorption line shape and then to allow retrievals of atmospheric column CO2 from the aircraft to cloud tops more than 90 % of the time. Retrievals from the CO2 measurements to cloud tops had minimal bias but larger standard deviations when compared to those made to the ground, depending on cloud top roughness and reflectance. The measurements show this new capability helps resolve CO2 horizontal and vertical gradients in the atmosphere. When used with nearby full-column measurements to ground, the CO2 measurements to cloud tops can be used to estimate the partial-column CO2 concentration below clouds, which should lead to better estimates of surface carbon sources and sinks. This additional capability of the range-resolved CO2 IPDA lidar technique provides a new benefit for studying the carbon cycle in future airborne and space-based CO2 missions.

  14. Single-Column Modeling, GCM Parameterizations and Atmospheric Radiation Measurement Data

    International Nuclear Information System (INIS)

    Somerville, R.C.J.; Iacobellis, S.F.

    2005-01-01

    Our overall goal is identical to that of the Atmospheric Radiation Measurement (ARM) Program: the development of new and improved parameterizations of cloud-radiation effects and related processes, using ARM data at all three ARM sites, and the implementation and testing of these parameterizations in global and regional models. To test recently developed prognostic parameterizations based on detailed cloud microphysics, we have first compared single-column model (SCM) output with ARM observations at the Southern Great Plains (SGP), North Slope of Alaska (NSA) and Topical Western Pacific (TWP) sites. We focus on the predicted cloud amounts and on a suite of radiative quantities strongly dependent on clouds, such as downwelling surface shortwave radiation. Our results demonstrate the superiority of parameterizations based on comprehensive treatments of cloud microphysics and cloud-radiative interactions. At the SGP and NSA sites, the SCM results simulate the ARM measurements well and are demonstrably more realistic than typical parameterizations found in conventional operational forecasting models. At the TWP site, the model performance depends strongly on details of the scheme, and the results of our diagnostic tests suggest ways to develop improved parameterizations better suited to simulating cloud-radiation interactions in the tropics generally. These advances have made it possible to take the next step and build on this progress, by incorporating our parameterization schemes in state-of-the-art 3D atmospheric models, and diagnosing and evaluating the results using independent data. Because the improved cloud-radiation results have been obtained largely via implementing detailed and physically comprehensive cloud microphysics, we anticipate that improved predictions of hydrologic cycle components, and hence of precipitation, may also be achievable. We are currently testing the performance of our ARM-based parameterizations in state-of-the--art global and regional

  15. Global CO emission estimates inferred from assimilation of MOPITT and IASI CO data, together with observations of O3, NO2, HNO3, and HCHO.

    Science.gov (United States)

    Zhang, X.; Jones, D. B. A.; Keller, M.; Jiang, Z.; Bourassa, A. E.; Degenstein, D. A.; Clerbaux, C.; Pierre-Francois, C.

    2017-12-01

    Atmospheric carbon monoxide (CO) emissions estimated from inverse modeling analyses exhibit large uncertainties, due, in part, to discrepancies in the tropospheric chemistry in atmospheric models. We attempt to reduce the uncertainties in CO emission estimates by constraining the modeled abundance of ozone (O3), nitrogen dioxide (NO2), nitric acid (HNO3), and formaldehyde (HCHO), which are constituents that play a key role in tropospheric chemistry. Using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system, we estimate CO emissions by assimilating observations of CO from the Measurement of Pollution In the Troposphere (MOPITT) and the Infrared Atmospheric Sounding Interferometer (IASI), together with observations of O3 from the Optical Spectrograph and InfraRed Imager System (OSIRIS) and IASI, NO2 and HCHO from the Ozone Monitoring Instrument (OMI), and HNO3 from the Microwave Limb Sounder (MLS). Our experiments evaluate the inferred CO emission estimates from major anthropogenic, biomass burning and biogenic sources. Moreover, we also infer surface emissions of nitrogen oxides (NOx = NO + NO2) and isoprene. Our results reveal that this multiple species chemical data assimilation produces a chemical consistent state that effectively adjusts the CO-O3-OH coupling in the model. The O3-induced changes in OH are particularly large in the tropics. Overall, our analysis results in a better constrained tropospheric chemical state.

  16. Airborne Measurements of CO2 Column Absorption and Range Using a Pulsed Direct-Detection Integrated Path Differential Absorption Lidar

    Science.gov (United States)

    Abshire, James B.; Riris, Haris; Weaver, Clark J.; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Browell, Edward V.

    2013-01-01

    We report on airborne CO2 column absorption measurements made in 2009 with a pulsed direct-detection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United States. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The lidar measurement statistics were also calculated for each flight as a function of altitude. The optical depth varied nearly linearly with altitude, consistent with calculations based on atmospheric models. The scatter in the optical depth measurements varied with aircraft altitude as expected, and the median measurement precisions for the column varied from 0.9 to 1.2 ppm. The altitude range with the lowest scatter was 810 km, and the majority of measurements for the column within it had precisions between 0.2 and 0.9 ppm.

  17. Validation of GOME (ERS-2) NO2 vertical column data with ground-based measurements at Issyk-Kul (Kyrgyzstan)

    Science.gov (United States)

    Ionov, D.; Sinyakov, V.; Semenov, V.

    Starting from 1995 the global monitoring of atmospheric nitrogen dioxide is carried out by the measurements of nadir-viewing GOME spectrometer aboard ERS-2 satellite. Continuous validation of that data by means of comparisons with well-controlled ground-based measurements is important to ensure the quality of GOME data products and improve related retrieval algorithms. At the station of Issyk-Kul (Kyrgyzstan) the ground-based spectroscopic observations of NO2 vertical column have been started since 1983. The station is located on the northern shore of Issyk-Kul lake, 1650 meters above the sea level (42.6 N, 77.0 E). The site is equipped with grating spectrometer for the twilight measurements of zenith-scattered solar radiation in the visible range, and applies the DOAS technique to retrieve NO2 vertical column. It is included in the list of NDSC stations as a complementary one. The present study is focused on validation of GOME NO2 vertical column data, based on 8-year comparison with correlative ground-based measurements at Issyk-Kul station in 1996-2003. Within the investigation, an agreement of both individual and monthly averaged GOME measurements with corresponding twilight ground-based observations is examined. Such agreement is analyzed with respect to different conditions (season, sun elevation), temporal/spatial criteria choice (actual overpass location, correction for diurnal variation) and data processing (GDP version 2.7, 3.0). In addition, NO2 vertical columns were integrated from simultaneous stratospheric profile measurements by NASA HALOE and SAGE-II/III satellite instruments and introduced to explain the differences with ground-based observations. In particular cases, NO2 vertical profiles retrieved from the twilight ground-based measurements at Issuk-Kul were also included into comparison. Overall, summertime GOME NO2 vertical columns were found to be systematicaly lower than ground-based data. This work was supported by International Association

  18. OMI/Aura Formaldehyde (HCHO) Total Column Global 0.25deg Lat/Lon Grid V003

    Data.gov (United States)

    National Aeronautics and Space Administration — The Version-3 Aura-OMI Formaldehyde Product OMHCHOG is now available (http://disc.gsfc.nasa.gov/Aura/OMI/omhchog_v003.shtml) from the NASA Goddard Earth Sciences...

  19. The Utility of the OMI HCHO and NO2 Data Products in Air Quality Decision- Making Activities

    Science.gov (United States)

    Duncan, Bryan N.

    2010-01-01

    We will present three related air quality applications of the OMI HCHO (formaldehyde) and NO2 (nitrogen dioxide) data products, which we us to support mission planning of an OMI-like instrument for the proposed GEO-CAPE satellite that has as one of its objectives to study air quality from space. First, we will discuss a novel and practical application of the data products to the "weight of evidence" in the air quality decision-making process (e.g., State Implementation Plan (SIP)) for a city, region, or state to demonstrate that it is making progress toward attainment of the National Ambient Air Quality Standard (NAAQS) for ozone. Any trend, or lack thereof, in the observed OMI HCHO/NO2, which we use as an air quality indicator, may support that an emission control strategy implemented to reduce ozone is or is not occurring for a metropolitan area. Second, we will discuss how we use variations in the OMI HCHO product as a proxy for variability in the biogenic hydrocarbon, isoprene, which is an important player for the formation of high levels of ozone and the dominant source of HCHO in the eastern U.S. Third, we will discuss the variability of NO2 in the U.S. as indicated by the OMI NO2 product. In addition, we will show the impact of the 2005 hurricanes on pollutant emissions, including those associated with the intensive oil extraction and refining activities, in the Gulf of Mexico region using the OMI NO2 product. The variability of HCHO and NO2 as indicated by OMI helps us to understand changes in the OMI HCHO/NO2 and the implications for ozone formation.

  20. A Novel Triple-Pulsed 2-micrometer Lidar for Simultaneous and Independent CO2 and H2O Column Measurement

    Science.gov (United States)

    Yu, Jirong; Singh, Upendra; Petros, Mulugeta; Refaat, Tamer

    2015-01-01

    The study of global warming needs precisely and accurately measuring greenhouse gases concentrations in the atmosphere. CO2 and H2O are important greenhouse gases that significantly contribute to the carbon cycle and global radiation budget on Earth. NRC Decadal Survey recommends a mission for Active Sensing of Carbon Dioxide (CO2) over Nights, Days and Seasons (ASCENDS). 2 micron laser is a viable IPDA transmitter to measure CO2 and H2O column density from space. The objective is to demonstrate a first airborne direct detection 2 micron IPDA lidar for CO2 and H2O measurements.

  1. Formaldehyde Column Density Measurements as a Suitable Pathway to Estimate Near-Surface Ozone Tendencies from Space

    Science.gov (United States)

    Schroeder, Jason R.; Crawford, James H.; Fried, Alan; Walega, James; Weinheimer, Andrew; Wisthaler, Armin; Mueller, Markus; Mikoviny, Tomas; Chen, Gao; Shook, Michael; hide

    2016-01-01

    In support of future satellite missions that aim to address the current shortcomings in measuring air quality from space, NASA's Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign was designed to enable exploration of relationships between column measurements of trace species relevant to air quality at high spatial and temporal resolution. In the DISCOVER-AQ data set, a modest correlation (r2 = 0.45) between ozone (O3) and formaldehyde (CH2O) column densities was observed. Further analysis revealed regional variability in the O3-CH2O relationship, with Maryland having a strong relationship when data were viewed temporally and Houston having a strong relationship when data were viewed spatially. These differences in regional behavior are attributed to differences in volatile organic compound (VOC) emissions. In Maryland, biogenic VOCs were responsible for approx.28% of CH2O formation within the boundary layer column, causing CH2O to, in general, increase monotonically throughout the day. In Houston, persistent anthropogenic emissions dominated the local hydrocarbon environment, and no discernable diurnal trend in CH2O was observed. Box model simulations suggested that ambient CH2O mixing ratios have a weak diurnal trend (+/-20% throughout the day) due to photochemical effects, and that larger diurnal trends are associated with changes in hydrocarbon precursors. Finally, mathematical relationships were developed from first principles and were able to replicate the different behaviors seen in Maryland and Houston. While studies would be necessary to validate these results and determine the regional applicability of the O3-CH2O relationship, the results presented here provide compelling insight into the ability of future satellite missions to aid in monitoring near-surface air quality.

  2. Computed Tomography Based Three-dimensional Measurements of Spine Shortening Distance After Posterior Three-column Osteotomies for the Treatment of Severe and Stiff Scoliosis.

    Science.gov (United States)

    Li, Xue-Shi; Huang, Zi-Fang; Deng, Yao-Long; Fan, Heng-Wei; Sui, Wen-Yuan; Wang, Chong-Wen; Yang, Jun-Lin

    2017-07-15

    Retrospective study. This study is to measure and analyze the changes of three-dimensional (3D) distances of spinal column and spinal canal at the three-column osteotomy sites and address their clinical and neurologic significance. Three-column osteotomies were developed to treat severe and stiff spine deformities with insufficient understanding on the safe limit of spine shortening and the relationship between the shortening distance of the spinal column and that of the spinal canal. Records of 52 continuous patients with severe and stiff scoliosis treated with three-column spine osteotomies at our institution from July 2013 to June 2015 were reviewed. The preoperative spinal cord function classification were type A in 31 cases, type B in 10 cases, and type C in 11 cases. The types of osteotomies carried out were extended pedicle subtraction osteotomy in nine patients and posterior vertebral column resection in 43 patients. Multimodality neuromonitoring strategies were adopted intraoperatively. 3D pre- and postoperative spine models were reconstructed from the computed tomography (CT) scans. The distances of convex and concave spinal column and the spinal canal shortening were measured and analyzed. The spinal column shortening distance (SCSD) measured on the 3D models (27.8 mm) were statistically shorter than those measured intraoperatively (32.8 mm) (P column strut graft than in those with bone-on-bone fusion (P column cannot represent that of the central spinal canal in patients with severe scoliosis. The spinal column shortening procedure in appropriately selected patient groups with bone-on-bone fusion is a viable option with the CCSD being significantly shorter than the convex SCSD. 4.

  3. Gamma ray transmission for hydraulic conductivity measurement of undisturbed soil columns

    Directory of Open Access Journals (Sweden)

    Anderson Camargo Moreira

    2007-03-01

    Full Text Available This work had the objective to determine the Hydraulic Conductivity K(theta function for different depth levels z, of columns of undisturbed soil, using the gamma ray transmission technique applied to the Sisson method. The results indicated a growing behavior for K(theta and a homogeneous soil density, both in relation to the increase of the depth. The methodology of gamma ray transmission showed satisfactory results on the determination of the hydraulic conductivity in columns of undisturbed soil, besides being very reliable and a nondestructive method.O estudo da condutividade hidráulica para solos não saturados é essencial quando aplicado às situações relacionadas à irrigação, drenagem e transporte de nutrientes no solo, é uma importante propriedade para desenvolvimentos de culturas agrícolas. Este trabalho tem o objetivo de determinar a função Condutividade Hidráulica K(teta, em diferentes níveis z de profundidade, em colunas de solo indeformado, utilizando a transmissão de raios gama aplicada ao método de Sisson. Os resultados indicam um comportamento crescente para K(teta e uma densidade de solo homogênea, ambos em relação ao aumento da profundidade. A metodologia de transmissão de raios gama mostrou resultados bastante satisfatórios na determinação da condutividade hidráulica em colunas de solo indeformado, além de ser muito confiável e não destrutivo.

  4. Modeling of intensity-modulated continuous-wave laser absorption spectrometer systems for atmospheric CO(2) column measurements.

    Science.gov (United States)

    Lin, Bing; Ismail, Syed; Wallace Harrison, F; Browell, Edward V; Nehrir, Amin R; Dobler, Jeremy; Moore, Berrien; Refaat, Tamer; Kooi, Susan A

    2013-10-10

    The focus of this study is to model and validate the performance of intensity-modulated continuous-wave (IM-CW) CO(2) laser absorption spectrometer (LAS) systems and their CO(2) column measurements from airborne and satellite platforms. The model accounts for all fundamental physics of the instruments and their related CO(2) measurement environments, and the modeling results are presented statistically from simulation ensembles that include noise sources and uncertainties related to the LAS instruments and the measurement environments. The characteristics of simulated LAS systems are based on existing technologies and their implementation in existing systems. The modeled instruments are specifically assumed to be IM-CW LAS systems such as the Exelis' airborne multifunctional fiber laser lidar (MFLL) operating in the 1.57 μm CO(2) absorption band. Atmospheric effects due to variations in CO(2), solar radiation, and thin clouds, are also included in the model. Model results are shown to agree well with LAS atmospheric CO(2) measurement performance. For example, the relative bias errors of both MFLL simulated and measured CO(2) differential optical depths were found to agree to within a few tenths of a percent when compared to the in situ observations from the flight of 3 August 2011 over Railroad Valley (RRV), Nevada, during the summer 2011 flight campaign. In addition, the horizontal variations in the model CO(2) differential optical depths were also found to be consistent with those from MFLL measurements. In general, the modeled and measured signal-to-noise ratios (SNRs) of the CO(2) column differential optical depths (τd) agreed to within about 30%. Model simulations of a spaceborne IM-CW LAS system in a 390 km dawn/dusk orbit for CO(2) column measurements showed that with a total of 42 W of transmitted power for one offline and two different sideline channels (placed at different locations on the side of the CO(2) absorption line), the accuracy of the

  5. A fast H2O total column density product from GOME – Validation with in-situ aircraft measurements

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2003-01-01

    Full Text Available Atmospheric water vapour is the most important greenhouse gas which is responsible for about 2/3 of the natural greenhouse effect, therefore changes in atmospheric water vapour in a changing climate (the water vapour feedback is subject to intense debate. H2O is also involved in many important reaction cycles of atmospheric chemistry, e.g. in the production of the OH radical. Thus, long time series of global H2O data are highly required. Since 1995 the Global Ozone Monitoring Experiment (GOME continuously observes atmospheric trace gases. In particular it has been demonstrated that GOME as a nadir looking UV/vis-instrument is sensitive to many tropospheric trace gases. Here we present a new, fast H2O algorithm for the retrieval of vertical column densities from GOME measurements. In contrast to existing H2O retrieval algorithms it does not depend on additional information like e.g. the climatic zone, aerosol content or ground albedo. It includes an internal cloud-, aerosol-, and albedo correction which is based on simultaneous observations of the oxygen dimer O4. From sensitivity studies using atmospheric radiative modelling we conclude that our H2O retrieval overestimates the true atmospheric H2O vertical column density (VCD by about 4% for clear sky observations in the tropics and sub-tropics, while it can lead to an underestimation of up to -18% in polar regions. For measurements over (partly cloud covered ground pixels, however, the true atmospheric H2O VCD might be in general systematically underestimated. We compared the GOME H2O VCDs to ECMWF model data over one whole GOME orbit (extending from the Arctic to the Antarctic including also totally cloud covered measurements. The correlation of the GOME observations and the model data yield the following results: a slope of 0.96 (r2 = 0.86 and an average bias of 5%. Even for measurements with large cloud fractions between 50% and 100% an average underestimation of only -18% was found. This

  6. Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption and Range During the ASCENDS 2009-2011 Airborne Campaigns

    Science.gov (United States)

    Abshire, J. B.; Weaver, C. J.; Riris, H.; Mao, J.; Sun, X.; Allan, G. R.; Hasselbrack, W. E.; Browell, E. V.

    2012-01-01

    We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar only on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear C02 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed in detail and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs

  7. A Comparison of Potential IM-CW Lidar Modulation Techniques for ASCENDS CO2 Column Measurements From Space

    Science.gov (United States)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Ismail, Syed

    2014-01-01

    Global atmospheric carbon dioxide (CO2) measurements through the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) Decadal Survey recommended space mission are critical for improving our understanding of CO2 sources and sinks. IM-CW (Intensity Modulated Continuous Wave) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS science requirements. In previous laboratory and flight experiments we have successfully used linear swept frequency modulation to discriminate surface lidar returns from intermediate aerosol and cloud contamination. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate clouds, which is a requirement for the inversion of the CO2 column-mixing ratio from the instrument optical depth measurements, has been demonstrated with the linear swept frequency modulation technique. We are concurrently investigating advanced techniques to help improve the auto-correlation properties of the transmitted waveform implemented through physical hardware to make cloud rejection more robust in special restricted scenarios. Several different carrier based modulation techniques are compared including orthogonal linear swept, orthogonal non-linear swept, and Binary Phase Shift Keying (BPSK). Techniques are investigated that reduce or eliminate sidelobes. These techniques have excellent auto-correlation properties while possessing a finite bandwidth (by way of a new cyclic digital filter), which will reduce bias error in the presence of multiple scatterers. Our analyses show that the studied modulation techniques can increase the accuracy of CO2 column measurements from space. A comparison of various properties such as signal to noise ratio (SNR) and time-bandwidth product are discussed.

  8. On the compatibility of Brewer total column ozone measurements in two adjacent valleys (Arosa and Davos in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    R. Stübi

    2017-11-01

    Full Text Available The Arosa site is well known in the ozone community for its continuous total ozone column observations that have been recorded since 1926. Originally based on Dobson sun spectrophotometers, the site has been gradually complemented by three automatic Brewer instruments, in operation since 1998. To secure the long-term ozone monitoring in this Alpine region and to benefit from synergies with the World Radiation Center, the feasibility of moving this activity to the nearby site at Davos (aerial distance of 13 km has been explored. Concerns about a possible rupture of the 90-year-long record has motivated a careful comparison of the two sites, since great attention to the data continuity and quality has always been central to the operations of the observatory at Arosa. To this end, one element of the Arosa Brewer triad has been set up at the Davos site since November 2011 to realize a campaign of parallel measurements and to study the deviations between the three Brewer instruments. The analysis of the coincident measurement shows that the differences between Arosa and Davos remain within the range of the long-term stability of the Brewer instruments. A nonsignificant seasonal cycle is observed, which could possibly be induced by a stray-light bias and the altitude difference between the two sites. These differences are shown to be lower than the short-term variability of the time series and the overall uncertainty from individual Brewer instruments and therefore are not statistically significant. It is therefore concluded that the world's longest time series of the total ozone column obtained at Arosa site could be safely extended and continued with measurements taken from instruments located at the nearby Davos site without introducing a bias to this unique record.

  9. Pre-column derivatisation method for the measurement of glycosylated hydroxylysines of collagenous proteins

    NARCIS (Netherlands)

    Bank, R.A.; Beekman, B.; Tenni, R.; Tekoppele, J.M.

    1997-01-01

    Measurement of the glycosylated hydroxylysines galactosyl- and glucosylgalactosylhydroxylysine (GH and GGH) in combination with other amino acids has been based on ion-exchange chromatography followed by reaction with ninhydrin. Here, a rapid and sensitive high-performance liquid chromatographic

  10. Adaption of an array spectroradiometer for total ozone column retrieval using direct solar irradiance measurements in the UV spectral range

    Science.gov (United States)

    Zuber, Ralf; Sperfeld, Peter; Riechelmann, Stefan; Nevas, Saulius; Sildoja, Meelis; Seckmeyer, Gunther

    2018-04-01

    A compact array spectroradiometer that enables precise and robust measurements of solar UV spectral direct irradiance is presented. We show that this instrument can retrieve total ozone column (TOC) accurately. The internal stray light, which is often the limiting factor for measurements in the UV spectral range and increases the uncertainty for TOC analysis, is physically reduced so that no other stray-light reduction methods, such as mathematical corrections, are necessary. The instrument has been extensively characterised at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. During an international total ozone measurement intercomparison at the Izaña Atmospheric Observatory in Tenerife, the high-quality applicability of the instrument was verified with measurements of the direct solar irradiance and subsequent TOC evaluations based on the spectral data measured between 12 and 30 September 2016. The results showed deviations of the TOC of less than 1.5 % from most other instruments in most situations and not exceeding 3 % from established TOC measurement systems such as Dobson or Brewer.

  11. Progress on Development of an Airborne Two-Micron IPDA Lidar for Water Vapor and Carbon Dioxide Column Measurements

    Science.gov (United States)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong; Antill, Charles W.; Taylor, Bryant D.; Bowen, Stephen C.; Welters, Angela M.; Remus, Ruben G.; Wong, Teh-Hwa; hide

    2014-01-01

    An airborne 2 micron triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This lidar targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements, simultaneously. Advancements in the development of this IPDA lidar are presented in this paper. Updates on advanced two-micron triple-pulse high-energy laser transmitter will be given including packaging and lidar integration status. In addition, receiver development updates will also be presented. This includes a state-of-the-art detection system integrated at NASA Goddard Space Flight Center. This detection system is based on a newly developed HgCdTe (MCT) electron-initiated avalanche photodiode (e-APD) array. Future plan for IPDA lidar system for ground integration, testing and flight validation will be discussed.

  12. Measuring and modeling three-dimensional water uptake of a growing faba bean (Vicia faba) within a soil column

    Science.gov (United States)

    Huber, Katrin; Koebernick, Nicolai; Kerkhofs, Elien; Vanderborght, Jan; Javaux, Mathieu; Vetterlein, Doris; Vereecken, Harry

    2014-05-01

    A faba bean was grown in a column filled with a sandy soil, which was initially close to saturation and then subjected to a single drying cycle of 30 days. The column was divided in four hydraulically separated compartments using horizontal paraffin layers. Paraffin is impermeable to water but penetrable by roots. Thus by growing deeper, the roots can reach compartments that still contain water. The root architecture was measured every second day by X-ray CT. Transpiration rate, soil matric potential in four different depths, and leaf area were measured continously during the experiment. To investigate the influence of the partitioning of available soil water in the soil column on water uptake, we used R-SWMS, a fully coupled root and soil water model [1]. We compared a scenario with and without the split layers and investigated the influence on root xylem pressure. The detailed three-dimensional root architecture was obtained by reconstructing binarized root images manually with a virtual reality system, located at the Juelich Supercomputing Centre [2]. To verify the properties of the root system, we compared total root lengths, root length density distributions and root surface with estimations derived from Minkowski functionals [3]. In a next step, knowing the change of root architecture in time, we could allocate an age to each root segment and use this information to define age dependent root hydraulic properties that are required to simulate water uptake for the growing root system. The scenario with the split layers showed locally much lower pressures than the scenario without splits. Redistribution of water within the unrestricted soil column led to a more uniform distribution of water uptake and lowers the water stress in the plant. However, comparison of simulated and measured pressure heads with tensiometers suggested that the paraffin layers were not perfectly hydraulically isolating the different soil layers. We could show compensation efficiency of

  13. Airborne Lidar for Simultaneous Measurement of Column CO2 and Water Vapor in the Atmosphere

    Science.gov (United States)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Antill, Charles W.; Remus, Ruben; Yu, Jirong

    2016-01-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption feathers for the gas at this particular wavelength. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers. This paper will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar. The development of this active optical remote sensing IPDA instrument is targeted for measuring both CO2 and water vapor (H2O) in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver telescope, detection system and data acquisition. Future plans for the IPDA lidar system for ground integration, testing and flight validation will also be presented.

  14. Measuring and modeling of a three-dimensional tracer transport in a planted soil column

    Science.gov (United States)

    Schroeder, N.; Javaux, M.; Haber-Pohlmeier, S.; Pohlmeier, A. J.; Huber, K.; Vereecken, H.; Vanderborght, J.

    2013-12-01

    Water flow from soil to root is driven by the plant transpiration and an important component of the hydrological cycle. The model R-SWMS combines three-dimensional (3D) water flow and solute transport in soil with a detailed description of root structure in three dimensions [1,2]. This model offers the possibility to calculate root water and solute uptake and flow within the roots, which enables explicit studies with respect to the distribution of water and solutes around the roots as well as local processes at the root-soil interface. In this study, we compared measured data from a tracer experiment using Magnetic Resonance Imaging (MRI) with simulations in order to assess the distribution and magnitude of the water uptake of a young lupine plant. An aqueous solution of the Gadolinium-complex (Gd-DTPA2-) was chosen as a tracer, as it behaves conservatively and is ideally suited for MRI. Water flow in the soil towards the roots can thus be visualized by following the change in tracer concentrations over time. The data were obtained by MRI, providing high resolution 3D images of the tracer distribution and root architecture structures by using a spin echo pulse sequence, which is strongly T1- weighted to be tracer sensitive [3], and T2 -weighted for root imaging [4]. This experimental setup was simulated using the 3D high-resolution numerical model R-SWMS. The comparison between MRI data and the simulations showed extensive effects of root architecture parameters on solute spreading. Although the results of our study showed the strength of combining non-invasive measurements and 3D modeling of solute and water flow in soil-root systems, where the derivation of plant hydraulic parameters such as axial and radial root conductivities is possible, current limitations were found with respect to MRI measurements and process description. [1] Javaux, M., T. Schröder, J. Vanderborght, and H. Vereecken (2008), Use of a Three-Dimensional Detailed Modeling Approach for

  15. Comparison of AOD, AAOD and column single scattering albedo from AERONET retrievals and in situ profiling measurements

    Science.gov (United States)

    Andrews, Elisabeth; Ogren, John A.; Kinne, Stefan; Samset, Bjorn

    2017-05-01

    Here we present new results comparing aerosol optical depth (AOD), aerosol absorption optical depth (AAOD) and column single scattering albedo (SSA) obtained from in situ vertical profile measurements with AERONET ground-based remote sensing from two rural, continental sites in the US. The profiles are closely matched in time (within ±3 h) and space (within 15 km) with the AERONET retrievals. We have used Level 1.5 inversion retrievals when there was a valid Level 2 almucantar retrieval in order to be able to compare AAOD and column SSA below AERONET's recommended loading constraint (AOD > 0.4 at 440 nm). While there is reasonable agreement for the AOD comparisons, the direct comparisons of in situ-derived to AERONET-retrieved AAOD (or SSA) reveal that AERONET retrievals yield higher aerosol absorption than obtained from the in situ profiles for the low aerosol optical depth conditions prevalent at the two study sites. However, it should be noted that the majority of SSA comparisons for AOD440 > 0.2 are, nonetheless, within the reported SSA uncertainty bounds. The observation that, relative to in situ measurements, AERONET inversions exhibit increased absorption potential at low AOD values is generally consistent with other published AERONET-in situ comparisons across a range of locations, atmospheric conditions and AOD values. This systematic difference in the comparisons suggests a bias in one or both of the methods, but we cannot assess whether the AERONET retrievals are biased towards high absorption or the in situ measurements are biased low. Based on the discrepancy between the AERONET and in situ values, we conclude that scaling modeled black carbon concentrations upwards to match AERONET retrievals of AAOD should be approached with caution as it may lead to aerosol absorption overestimates in regions of low AOD. Both AERONET retrievals and in situ measurements suggest there is a systematic relationship between SSA and aerosol amount (AOD or aerosol light

  16. The effect of high column density systems on the measurement of the Lyman-α forest correlation function

    Energy Technology Data Exchange (ETDEWEB)

    Font-Ribera, Andreu [Institut de Ciències de l' Espai (IEEC-CSIC), E. de Ciències, Torre C5, Bellaterra, Catalonia (Spain); Miralda-Escudé, Jordi, E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia (Spain)

    2012-07-01

    We present a study of the effect of High Column Density (HCD) systems on the Lyα forest correlation function on large scales. We study the effect both numerically, by inserting HCD systems on mock spectra for a specific model, and analytically, in the context of two-point correlations and linear theory. We show that the presence of HCDs substantially contributes to the noise of the correlation function measurement, and systematically alters the measured redshift-space correlation function of the Lyα forest, increasing the value of the density bias factor and decreasing the redshift distortion parameter β{sub α} of the Lyα forest. We provide simple formulae for corrections on these derived parameters, as a function of the mean effective optical depth and bias factor of the host halos of the HCDs, and discuss the conditions under which these expressions should be valid. In practice, precise corrections to the measured parameters of the Lyα forest correlation for the HCD effects are more complex than the simple analytical approximations we present, owing to non-linear effects of the damped wings of the HCD systems and the presence of three-point terms. However, we conclude that an accurate correction for these HCD effects can be obtained numerically and calibrated with observations of the HCD-Lyα cross-correlation. We also discuss an analogous formalism to treat and correct for the contaminating effect of metal lines overlapping the Lyα forest spectra.

  17. Measurements of the residual stresses in the welded steel columns based on the x-ray diffraction method, 2

    International Nuclear Information System (INIS)

    Kaneta, Kiyoshi; Nishizawa, Hidekazu; Arashiyama, Masaki.

    1982-01-01

    In order to evaluate the applicability of two kinds of techniques of the X-ray stress analysis, namely, the standard sin 2 psi method and the newly developed phi-sin 2 psi method, bending tests have been performed. The test results have proved that the values of the stresses measured by means of the mechanical devices and of those measured by the two kinds of the X-ray techniques coincide each other. Then, these two methods have been applied to measure the surface residual stresses of the box-typed, welded steel columns and the following conclusions have been drawn. 1. The principal stress of the surface residural stresses is, in most cases, oriented to the rolled directions at the center of the steel plates, and it tends to rotate in the neighborhood of the heat affected zones. 2. Tensile residual stresses of a large magnitude have been observed in the direction parallel to the beads of the weld, and the moderate compressive residual stresses can be detected in the direction normal to the beads. (author)

  18. Development of Double and Triple-Pulsed 2-micron IPDA Lidars for Column CO2 Measurements

    Science.gov (United States)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Reithmaier, Karl

    2015-01-01

    Carbon dioxide (CO2) is an important greenhouse gas that significantly contributes to the carbon cycle and globalradiation budget on Earth. CO2 role on Earth’s climate is complicated due to different interactions with various climatecomponents that include the atmosphere, the biosphere and the hydrosphere. Although extensive worldwide efforts formonitoring atmospheric CO2 through various techniques, including in-situ and passive sensors, are taking place highuncertainties exist in quantifying CO2 sources and sinks. These uncertainties are mainly due to insufficient spatial andtemporal mapping of the gas. Therefore it is required to have more rapid and accurate CO2 monitoring with higheruniform coverage and higher resolution. CO2 DIAL operating in the 2-µm band offer better near-surface CO2measurement sensitivity due to the intrinsically stronger absorption lines. For more than 15 years, NASA LangleyResearch Center (LaRC) contributed in developing several 2-?m CO2 DIAL systems and technologies. This paperfocuses on the current development of the airborne double-pulsed and triple-pulsed 2-?m CO2 integrated pathdifferential absorption (IPDA) lidar system at NASA LaRC. This includes the IPDA system development andintegration. Results from ground and airborne CO2 IPDA testing will be presented. The potential of scaling suchtechnology to a space mission will be addressed.

  19. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  20. Probabilistic global maps of the CO2 column at daily and monthly scales from sparse satellite measurements

    Science.gov (United States)

    Chevallier, Frédéric; Broquet, Grégoire; Pierangelo, Clémence; Crisp, David

    2017-07-01

    The column-average dry air-mole fraction of carbon dioxide in the atmosphere (XCO2) is measured by scattered satellite measurements like those from the Orbiting Carbon Observatory (OCO-2). We show that global continuous maps of XCO2 (corresponding to level 3 of the satellite data) at daily or coarser temporal resolution can be inferred from these data with a Kalman filter built on a model of persistence. Our application of this approach on 2 years of OCO-2 retrievals indicates that the filter provides better information than a climatology of XCO2 at both daily and monthly scales. Provided that the assigned observation uncertainty statistics are tuned in each grid cell of the XCO2 maps from an objective method (based on consistency diagnostics), the errors predicted by the filter at daily and monthly scales represent the true error statistics reasonably well, except for a bias in the high latitudes of the winter hemisphere and a lack of resolution (i.e., a too small discrimination skill) of the predicted error standard deviations. Due to the sparse satellite sampling, the broad-scale patterns of XCO2 described by the filter seem to lag behind the real signals by a few weeks. Finally, the filter offers interesting insights into the quality of the retrievals, both in terms of random and systematic errors.

  1. Retrieval of tropospheric NO2 vertical column densities and aerosol optical properties form MAXDOAS measurements in Yangtze River Delta, China

    Science.gov (United States)

    Hao, Nan; Van. Roozendael, Michel; Ding, Aijun; Zhou, Bin; Hendrick, François; Shen, Yicheng; Wang, Tin; Valks, Pieter

    2014-05-01

    Air pollution is one of the most important environmental problems in developing Asian countries like China. Due to huge consumption of fossil fuels and rapid increase of traffic emissions in the past decades, many regions in China have been experiencing heavy air pollution. The Yangtze River Delta (YRD) region includes the mega-city Shanghai and the well-industrialized and urbanized areas of Zhejiang Province and Jiangsu Province, with over ten large cities, such as Hangzhou, Suzhou and Nanjing. Covering only 2% land area, this region produces over 20% of China's Gross Domestic Product (GDP) which makes it the most densely populated region and one of the most polluted regions in China. For instance, there more than 60% of a year was haze days with poor visibility in Shanghai over the last few years. In the YRD region, knowledge gaps still exist in the understanding of the source and transport of air pollutants because only few measurement studies have been conducted. MAX-DOAS measurements were performed in Shanghai city center and Wujiang (border of Shanghai and Jiangsu Province) from 2010 to 2012 and in Nanjing (capital of Jiangsu Province) from April 2013. A retrieval algorithm, based on an on-line implementation of the radiative transfer code LIDORT and the optimal estimation technique, has been used to provide information on aerosol extinction vertical profiles. The total aerosol optical depths (AODs) calculated from the retrieved profiles were compared to MODIS, AERONET and local PM measurements. The aerosol information was input to LIDORT to calculate NO2 air mass factors. The retrieved tropospheric NO2 vertical column densities (VCDs) were compared to in-situ and satellite NO2 measurements.

  2. Discrete Water Column Measurements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southeast Fisheries Science Center Mississippi Laboratories conducts standardized fisheries independent resource surveys in the Gulf of Mexico, South Atlantic,...

  3. Further evaluation of wetland emission estimates from the JULES land surface model using SCIAMACHY and GOSAT atmospheric column methane measurements

    Science.gov (United States)

    Hayman, Garry; Comyn-Platt, Edward; McNorton, Joey; Chipperfield, Martyn; Gedney, Nicola

    2016-04-01

    The atmospheric concentration of methane began rising again in 2007 after a period of near-zero growth [1,2], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics since then. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [2,3]. Wetlands are generally accepted as being the largest, but least well quantified, single natural source of CH4, with global emission estimates ranging from 142-284 Tg yr-1 [3]. The modelling of wetlands and their associated emissions of CH4 has become the subject of much current interest [4]. We have previously used the HadGEM2 chemistry-climate model to evaluate the wetland emission estimates derived using the UK community land surface model (JULES, the Joint UK Land Earth Simulator) against atmospheric observations of methane, including SCIAMACHY total methane columns [5] up to 2007. We have undertaken a series of new HadGEM2 runs using new JULES emission estimates extended in time to the end of 2012, thereby allowing comparison with both SCIAMACHY and GOSAT atmospheric column methane measurements. We will describe the results of these runs and the implications for methane wetland emissions. References [1] Rigby, M., et al.: Renewed growth of atmospheric methane. Geophys. Res. Lett., 35, L22805, 2008; [2] Nisbet, E.G., et al.: Methane on the Rise-Again, Science 343, 493, 2014; [3] Kirschke, S., et al.,: Three decades of global methane sources and sinks, Nature Geosciences, 6, 813-823, 2013; [4] Melton, J. R., et al.: Present state of global wetland extent and wetland methane modelling: conclusions from a model inter-comparison project (WETCHIMP), Biogeosciences, 10, 753-788, 2013; [5] Hayman, G.D., et al.: Comparison of the HadGEM2 climate-chemistry model against in situ and SCIAMACHY atmospheric methane data, Atmos. Chem

  4. Performance of a geostationary mission, geoCARB, to measure CO2, CH4 and CO column-averaged concentrations

    Directory of Open Access Journals (Sweden)

    I. N. Polonsky

    2014-04-01

    Full Text Available GeoCARB is a proposed instrument to measure column averaged concentrations of CO2, CH4 and CO from geostationary orbit using reflected sunlight in near-infrared absorption bands of the gases. The scanning options, spectral channels and noise characteristics of geoCARB and two descope options are described. The accuracy of concentrations from geoCARB data is investigated using end-to-end retrievals; spectra at the top of the atmosphere in the geoCARB bands are simulated with realistic trace gas profiles, meteorology, aerosol, cloud and surface properties, and then the concentrations of CO2, CH4 and CO are estimated from the spectra after addition of noise characteristic of geoCARB. The sensitivity of the algorithm to aerosol, the prior distributions assumed for the gases and the meteorology are investigated. The contiguous spatial sampling and fine temporal resolution of geoCARB open the possibility of monitoring localised sources such as power plants. Simulations of emissions from a power plant with a Gaussian plume are conducted to assess the accuracy with which the emission strength may be recovered from geoCARB spectra. Scenarios for "clean" and "dirty" power plants are examined. It is found that a reliable estimate of the emission rate is possible, especially for power plants that have particulate filters, by averaging emission rates estimated from multiple snapshots of the CO2 field surrounding the plant. The result holds even in the presence of partial cloud cover.

  5. Feasibility of retrieving dust properties and total column water vapor from solar spectra measured using a lander camera on Mars

    Science.gov (United States)

    Manago, Naohiro; Noguchi, Katsuyuki; Hashimoto, George L.; Senshu, Hiroki; Otobe, Naohito; Suzuki, Makoto; Kuze, Hiroaki

    2017-12-01

    Dust and water vapor are important constituents in the Martian atmosphere, exerting significant influence on the heat balance of the atmosphere and surface. We have developed a method to retrieve optical and physical properties of Martian dust from spectral intensities of direct and scattered solar radiation to be measured using a multi-wavelength environmental camera onboard a Mars lander. Martian dust is assumed to be composed of silicate-like substrate and hematite-like inclusion, having spheroidal shape with a monomodal gamma size distribution. Error analysis based on simulated data reveals that appropriate combinations of three bands centered at 450, 550, and 675 nm wavelengths and 4 scattering angles of 3°, 10°, 50°, and 120° lead to good retrieval of four dust parameters, namely, aerosol optical depth, effective radius and variance of size distribution, and volume mixing ratio of hematite. Retrieval error increases when some of the observational parameters such as color ratio or aureole are omitted from the retrieval. Also, the capability of retrieving total column water vapor is examined through observations of direct and scattered solar radiation intensities at 925, 935, and 972 nm. The simulation and error analysis presented here will be useful for designing an environmental camera that can elucidate the dust and water vapor properties in a future Mars lander mission.

  6. Water vapor total column measurements using the Elodie Archive at Observatoire de Haute Provence from 1994 to 2004

    Directory of Open Access Journals (Sweden)

    A. Sarkissian

    2009-07-01

    Full Text Available Water vapor total column measurements at Observatoire de Haute Provence (5°42´ E, +43°55´ N, south of France, were obtained using observations of astronomical objects made between July 1994 and December 2004 on the 193-cm telescope with the high-resolution spectrometer Elodie. Spectra of stars, nebulae, and other astronomical objects were taken regularly during 10 years. More than 18 000 spectra from 400 nm to 680 nm are available on-line in the Elodie Archive. This archive, usually explored by astronomers, contains information to study the atmosphere of the Earth. Water vapor absorption lines appear in the visible in delimited bands that astronomers often avoid for their spectral analysis. We used the Elodie Archive with two objectives: firstly, to retrieve seasonal variability and long-term trend of atmospheric water vapor, and secondly, to remove signatures in spectra for further astronomical or geophysical use. The tools presented here (the workflow, the interoperable Elodie Archive and the web service Tellodie are developed following, when possible, formats and standards recommended by the International Virtual Observatory Alliance.

  7. Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2010-11-23

    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  8. Measurements of Atmospheric CO2 Column in Cloudy Weather Conditions using An IM-CW Lidar at 1.57 Micron

    Science.gov (United States)

    Lin, Bing; Obland, Michael; Harrison, F. Wallace; Nehrir, Amin; Browell, Edward; Campbell, Joel; Dobler, Jeremy; Meadows, Bryon; Fan, Tai-Fang; Kooi, Susan; hide

    2015-01-01

    This study evaluates the capability of atmospheric CO2 column measurements under cloudy conditions using an airborne intensity-modulated continuous-wave integrated-path-differential-absorption lidar operating in the 1.57-m CO2 absorption band. The atmospheric CO2 column amounts from the aircraft to the tops of optically thick cumulus clouds and to the surface in the presence of optically thin clouds are retrieved from lidar data obtained during the summer 2011 and spring 2013 flight campaigns, respectively.

  9. Plasma column displacement measurements by modified Rogowski sine-coil and Biot-Savart/magnetic flux equation solution on IR-T1 tokamak

    International Nuclear Information System (INIS)

    Razavi, M.; Mollai, M.; Khorshid, P.; Nedzelskiy, I.; Ghoranneviss, M.

    2010-01-01

    The modified Rogowski sine-coil (MRSC) has been designed and implemented for the plasma column horizontal displacement measurements on small IR-T1 tokamak. MRSC operation has been examined on test assembly and tokamak. Obtained results show high sensitivity to the plasma column horizontal displacement and negligible sensitivity to the vertical displacement; linearity in wide, ±0.1 m, range of the displacements; and excellent, 1.5%, agreement with the results of numerical solution of Biot-Savart and magnetic flux equations.

  10. Monoclinic α-Bi2O3 photocatalyst for efficient removal of gaseous NO and HCHO under visible light irradiation

    International Nuclear Information System (INIS)

    Ai Zhihui; Huang Yu; Lee Shuncheng; Zhang Lizhi

    2011-01-01

    Research highlights: → We got the monoclinic α-Bi 2 O 3 powders after the calcinations of the plate-like (BiO) 2 CO 3 precursors at 500 deg. C for 4 h. → The synthetic α-Bi 2 O 3 showed high visible light photocatalytic activity for removal of NO and HCHO. - Abstract: The investigation was focused on the visible-light-driven photocatalytic removal of gaseous NO and HCHO at typical indoor air concentration over synthetic α-Bi 2 O 3 . Monoclinic α-Bi 2 O 3 was synthesized via calcination of hydrothermally prepared (BiO) 2 CO 3 precursor at 500 deg. C for 4 h. The synthetic α-Bi 2 O 3 samples were systematically characterized by XRD, SEM, FT-IR, and UV-vis diffuse reflectance spectra (DRS). The optical band gap energy of the resulting α-Bi 2 O 3 was estimated to be 2.72 eV from the UV-vis absorption spectra. Comparing with the commercial Bi 2 O 3 counterpart, the fabricated α-Bi 2 O 3 showed superior visible-light-induced photocatalytic activity on degradation of nitrogen monoxide (NO) and formaldehyde (HCHO) at typical indoor air concentration. No obvious deactivation of synthetic α-Bi 2 O 3 was observed during the prolonged photocatalytic reaction. This work suggests that the synthesized monoclinic α-Bi 2 O 3 with suitable band gap and high activity is promising photocatalyst for indoor air purification.

  11. Carbon monoxide column retrieval for clear-sky and cloudy atmospheres : A full-mission data set from SCIAMACHY 2.3 μm reflectance measurements

    NARCIS (Netherlands)

    Borsdorff, Tobias; De Brugh, Joost Aan; Hu, Haili; Nédélec, Philippe; Aben, Ilse; Landgraf, Jochen

    2017-01-01

    We discuss the retrieval of carbon monoxide (CO) vertical column densities from clear-sky and cloud contaminated 2311-2338 nm reflectance spectra measured by the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) from January 2003 until the end of the mission in April

  12. Atmospheric CO2 Column Measurements with an Airborne Intensity-Modulated Continuous-Wave 1.57-micron Fiber Laser Lidar

    Science.gov (United States)

    Dobler, Jeremy T.; Harrison, F. Wallace; Browell, Edward V.; Lin, Bing; McGregor, Doug; Kooi, Susan; Choi, Yonghoon; Ismail, Syed

    2013-01-01

    The 2007 National Research Council (NRC) Decadal Survey on Earth Science and Applications from Space recommended Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as a mid-term, Tier II, NASA space mission. ITT Exelis, formerly ITT Corp., and NASA Langley Research Center have been working together since 2004 to develop and demonstrate a prototype Laser Absorption Spectrometer for making high-precision, column CO2 mixing ratio measurements needed for the ASCENDS mission. This instrument, called the Multifunctional Fiber Laser Lidar (MFLL), operates in an intensity-modulated, continuous-wave mode in the 1.57- micron CO2 absorption band. Flight experiments have been conducted with the MFLL on a Lear-25, UC-12, and DC-8 aircraft over a variety of different surfaces and under a wide range of atmospheric conditions. Very high-precision CO2 column measurements resulting from high signal-to-noise (great than 1300) column optical depth measurements for a 10-s (approximately 1 km) averaging interval have been achieved. In situ measurements of atmospheric CO2 profiles were used to derive the expected CO2 column values, and when compared to the MFLL measurements over desert and vegetated surfaces, the MFLL measurements were found to agree with the in situ-derived CO2 columns to within an average of 0.17% or approximately 0.65 ppmv with a standard deviation of 0.44% or approximately 1.7 ppmv. Initial results demonstrating ranging capability using a swept modulation technique are also presented.

  13. MAX-DOAS aerosol and trace gases measurements in megacities in China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin [Institut fuer Energie- und Klimaforschung, Forschungszentrum Juelich (Germany); College of Environmental Science and Engineering Peking University, Beijing (China); Brauers, Theo [Institut fuer Energie- und Klimaforschung, Forschungszentrum Juelich (Germany); Shao, Min [College of Environmental Science and Engineering Peking University, Beijing (China)

    2011-07-01

    Multi Axis Differential Optical Absorption Spectroscopy (MAXDOAS) is a new remote sensing technique to measure atmospheric trace gases. Compared to other areas in the world, the atmospheric observations in megacities in China are rather limited. We present MAX-DOAS measurements at four sites in Beijing and Guangzhou in 2006 and 2008. At each site, the scattered sunlight was recorded at 7 elevation angles for about 1 months. Using the zenith spectrum as reference, the Differential Slant Column Densities (DSCDs) of HCHO, CHOCHO, O{sub 4} and NO{sub 2} at offaxis viewing geometries were derived from the DOAS fit. These DSCDs were simulated using a backward Monte Carlo radiative transfer model. The aerosol and trace gas profiles were defined by 3 parameters: the integrated quantities (T), the height of the surface layer (H), and the fraction of T below H. We fitted the modeled values to the measured values at the corresponding viewing geometries by varying the 3 parameters. The aerosol extinction and the boundary layer height were successfully retrieved from the measured O{sub 4} DSCDs as well as ground level concentrations of CHOCHO, HCHO, and NO{sub 2}, the latter being compared to simultaneous in-situ measurements.

  14. Glacial–interglacial dynamics of Antarctic firn columns: comparison between simulations and ice core air-δ15N measurements

    Directory of Open Access Journals (Sweden)

    E. Capron

    2013-05-01

    Full Text Available Correct estimation of the firn lock-in depth is essential for correctly linking gas and ice chronologies in ice core studies. Here, two approaches to constrain the firn depth evolution in Antarctica are presented over the last deglaciation: outputs of a firn densification model, and measurements of δ15N of N2 in air trapped in ice core, assuming that δ15N is only affected by gravitational fractionation in the firn column. Since the firn densification process is largely governed by surface temperature and accumulation rate, we have investigated four ice cores drilled in coastal (Berkner Island, BI, and James Ross Island, JRI and semi-coastal (TALDICE and EPICA Dronning Maud Land, EDML Antarctic regions. Combined with available ice core air-δ15N measurements from the EPICA Dome C (EDC site, the studied regions encompass a large range of surface accumulation rates and temperature conditions. Our δ15N profiles reveal a heterogeneous response of the firn structure to glacial–interglacial climatic changes. While firn densification simulations correctly predict TALDICE δ15N variations, they systematically fail to capture the large millennial-scale δ15N variations measured at BI and the δ15N glacial levels measured at JRI and EDML – a mismatch previously reported for central East Antarctic ice cores. New constraints of the EDML gas–ice depth offset during the Laschamp event (~41 ka and the last deglaciation do not favour the hypothesis of a large convective zone within the firn as the explanation of the glacial firn model–δ15N data mismatch for this site. While we could not conduct an in-depth study of the influence of impurities in snow for firnification from the existing datasets, our detailed comparison between the δ15N profiles and firn model simulations under different temperature and accumulation rate scenarios suggests that the role of accumulation rate may have been underestimated in the current description of firnification

  15. Differential coulometric oxidation following post column-switching high pressure liquid chromatography for fluorescence measurement of unmetabolized folic acid in human plasma.

    Science.gov (United States)

    Bailey, Steven W; Ayling, June E

    2013-11-08

    Although many countries have fortified their grain supplies with folic acid (FA) to decrease the incidence of neural tube defects, others have not due to concerns that this synthetic folate might have some adverse effects. Persistent unmetabolized FA has been found even in plasma from fasted subjects. To facilitate measurement of low levels of folic acid in human plasma, post-column coulometric oxidative cleavage was used to convert poorly fluorescent FA into a highly fluorescent compound determined to be 6-formyl-pterin. To minimize sample work-up and maximize recovery, column-switching HPLC transferred a window of eluate containing the FA from the first column (C8) onto a second column (phenyl-hexyl). The pH of two mobile phases were adjusted to be above and then below a pK of the FA α-carboxyl group, thus promoting separation from compounds coeluting from the C8-column. This permitted sample preparation using only a simple high recovery protein precipitation. Definitive identification of FA in human plasma was accomplished by duplicate injections of sample with the electrochemical voltage set above and below its half-potential. The LOD (S/N=3) was 0.10 nM. The intra- and inter-assay CV's were 2.3% and 5%, respectively. Comparison of these results with those obtained by HPLC/MS/MS with stable isotope internal standard showed a slope of 1.00 ± 0.019. This simple, sensitive, and repeatable assay facilitates a more thorough investigation of the response of various human populations to folic acid intake. Post-column differential coulometric electrochemistry can expand the variety of compounds amenable to fluorescence detection. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Field Results from Three Campaigns to Validate the Performance of the Miniaturized Laser Heterodyne Radiometer (Mini-LHR) for Measuring Carbon Dioxide and Methane in the Atmospheric Column

    Science.gov (United States)

    Miller, J. Houston; Clarke, Greg B.; Melroy, Hilary; Ott, Lesley; Steel, Emily Wilson

    2014-01-01

    In a collaboration between NASA GSFC and GWU, a low-cost, surface instrument is being developed that can continuously monitor key carbon cycle gases in the atmospheric column: carbon dioxide (CO2) and methane (CH4). The instrument is based on a miniaturized, laser heterodyne radiometer (LHR) using near infrared (NIR) telecom lasers. Despite relatively weak absorption line strengths in this spectral region, spectrallyresolved atmospheric column absorptions for these two molecules fall in the range of 60-80% and thus sensitive and precise measurements of column concentrations are possible. In the last year, the instrument was deployed for field measurements at Park Falls, Wisconsin; Castle Airport near Atwater, California; and at the NOAA Mauna Loa Observatory in Hawaii. For each subsequent campaign, improvement in the figures of merit for the instrument has been observed. In the latest work the absorbance noise is approaching 0.002 optical density (OD) noise on a 1.8 OD signal. An overview of the measurement campaigns and the data retrieval algorithm for the calculation of column concentrations will be presented. For light transmission through the atmosphere, it is necessary to account for variation of pressure, temperature, composition, and refractive index through the atmosphere that are all functions of latitude, longitude, time of day, altitude, etc. For temperature, pressure, and humidity profiles with altitude we use the Modern-Era Retrospective Analysis for Research and Applications (MERRA) data. Spectral simulation is accomplished by integrating short-path segments along the trajectory using the SpecSyn spectral simulation suite developed at GW. Column concentrations are extracted by minimizing residuals between observed and modeled spectrum using the Nelder-Mead simplex algorithm. We will also present an assessment of uncertainty in the reported concentrations from assumptions made in the meteorological data, LHR instrument and tracker noise, and radio

  17. Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

    Science.gov (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

    2017-12-08

    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  18. A purge-and-trap capillary column gas chromatographic method for the measurement of halocarbons in water and air

    Energy Technology Data Exchange (ETDEWEB)

    Happell, J.D.; Wallace, D.W.R.; Wills, K.D.; Wilke, R.J.; Neill, C.C.

    1996-06-01

    This report describes an automated, accurate, precise and sensitive capillary column purge- and -trap method capable of quantifying CFC-12, CFC-11, CFC-113, CH{sub 3}CCL{sub 3}, and CCL{sub 4} during a single chromatographic analysis in either water or gas phase samples.

  19. MAX-DOAS tropospheric nitrogen dioxide column measurements compared with the Lotos-Euros air quality model

    NARCIS (Netherlands)

    Vlemmix, T.; Eskes, H.J.; Piters, A.J.M.; Schaap, M.; Sauter, F.J.; Kelder, H.; Levelt, P.F.

    2015-01-01

    A 14-month data set of MAX-DOAS (Multi-Axis Differential Optical Absorption Spectroscopy) tropospheric NO2 column observations in De Bilt, the Netherlands, has been compared with the regional air quality model Lotos-Euros. The model was run on a 7×7 km2 grid, the same resolution as the emission

  20. Studies on the liquid-liquid phase distribution equilibria of selenium and its measurement in water using extraction plant with a pulsation column

    International Nuclear Information System (INIS)

    Iskanderani, F.; Sobhi, K.M.; Ejaz, M.

    1989-01-01

    Normal heptane, xylene and a 0.01 molar solution of 4-(5-nonyl)pyridine in toluene were investigated as extractants for selenium(IV) from nitric acid media in potassium iodide. Various parameters affecting the distribution of the element are investigated. Extraction at high aqueous to organic phase volume ratio was studied, using a liquid-liquid extraction plant with a pulsation column. The results were employed to measure selenium in spiked water samples. (author) 24 refs.; 8 figs

  1. Load-bearing evaluation of spinal posterior column by measuring surface strain from lumbar pedicles. An in vitro study.

    Science.gov (United States)

    Sun, Peidong; Zhao, Weidong; Bi, Zhenyu; Wu, Changfu; Ouyang, Jun

    2012-01-01

    An understanding of the load transfer within spinal posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant such as artificial intervertebral disc and the dynamic spine stabilization systems. In this study, a new method has been developed for evaluating the load bearing of spinal posterior column by the surface strain of spinal pedicle response to the loading of spinal segment. Six cadaveric lumbar spine segments were biomechanically evaluated between levels L1 and L5 in intact condition and the strain gauges were pasted to an inferior surface of L2 pedicles. Multidirectional flexibility testing used the Panjabi testing protocol; pure moments for the intact condition with overall spinal motion and unconstrained intact moments of ±8 Nm were used for flexion-extension and lateral bending testing. High correlation coefficient (0.967-0.998) indicated a good agreement between the load of spinal segment and the surface strain of pedicle in all loading directions. Principal compressive strain could be observed in flexion direction and tensile strain in extension direction, respectively. In conclusion, the new method seems to be effective for evaluating posterior spinal column loads using pedicles' surface strain data collected during biomechanical testing of spine segments.

  2. Safety barriers and lighting columns.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1972-01-01

    Problems arising from the sitting of lighting columns on the central reserve are reviewed, and remedial measures such as break-away lighting supports and installation of safety fences on the central reserve on both sides of the lighting columns are examined.

  3. Specially Treated Aramid Fiber Stabilized Gel-Emulsions: Preparation of Porous Polymeric Monoliths and Highly Efficient Removing of Airborne HCHO.

    Science.gov (United States)

    Liu, Jianfei; Chen, Xiangli; Wang, Pei; Fu, Xuwei; Liu, Kaiqiang; Fang, Yu

    2017-08-01

    Porous polymeric monoliths with densities as low as ≈0.060 g cm -3 are prepared in a gel-emulsion template way, of which the stabilizer employed is a newly discovered acidified aramid fiber that is so efficient that 0.05% (w/v, accounts for continuous phase) is enough to gel the system. The porous monoliths as obtained can be dried at ambient conditions, avoiding energy-consuming processes. Importantly, the monoliths show selective adsorption to HCHO, and the corresponding adsorption capacity (M6) is ≈2700 mg g -1 , the best result that is reported until now. More importantly, the monoliths can be reused after drying. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. An Investigation of an Irradiated Fuel Pin by Measurement of the Production of Fast Neutrons in a Thermal Column and by Pile Oscillation Technique

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Veine

    1968-05-15

    A fuel pin irradiated to about 3400 MWd/tU from the Halden reactor has been investigated by a measurement of the production of fast neutrons in a thermal column and by pile oscillator technique in the central channel of the reactor R1. Calibration was made by using samples with different U 235 enrichments. The thermal column experiment gives the quantity ave({nu}{sigma}{sub f}) (average in the thermal column spectrum) for the Halden sample. {sigma}{sub f} is the macroscopic fission cross section and {nu} is the number of fast neutrons produced per fission. The result of the oscillator measurements is a value of ave({sigma}{sub a}) - w ave({sigma}{sub f}) (average in the central channel spectrum) for the irradiated sample, w is the importance of a fast neutron relative to a thermal one and ave({sigma}{sub a}) is the macroscopic absorption cross section. The results from both the experiments have been compared with values calculated by the REBUS code and the agreement was good.

  5. An Investigation of an Irradiated Fuel Pin by Measurement of the Production of Fast Neutrons in a Thermal Column and by Pile Oscillation Technique

    International Nuclear Information System (INIS)

    Gustavsson, Veine

    1968-05-01

    A fuel pin irradiated to about 3400 MWd/tU from the Halden reactor has been investigated by a measurement of the production of fast neutrons in a thermal column and by pile oscillator technique in the central channel of the reactor R1. Calibration was made by using samples with different U 235 enrichments. The thermal column experiment gives the quantity ave(νΣ f ) (average in the thermal column spectrum) for the Halden sample. Σ f is the macroscopic fission cross section and ν is the number of fast neutrons produced per fission. The result of the oscillator measurements is a value of ave(Σ a ) - w ave(Σ f ) (average in the central channel spectrum) for the irradiated sample, w is the importance of a fast neutron relative to a thermal one and ave(Σ a ) is the macroscopic absorption cross section. The results from both the experiments have been compared with values calculated by the REBUS code and the agreement was good

  6. Development of gas chromatography-flame ionization detection system with a single column and liquid nitrogen-free for measuring atmospheric C2-C12 hydrocarbons.

    Science.gov (United States)

    Liu, Chengtang; Mu, Yujing; Zhang, Chenglong; Zhang, Zhibo; Zhang, Yuanyuan; Liu, Junfeng; Sheng, Jiujiang; Quan, Jiannong

    2016-01-04

    A liquid nitrogen-free GC-FID system equipped with a single column has been developed for measuring atmospheric C2-C12 hydrocarbons. The system is consisted of a cooling unit, a sampling unit and a separation unit. The cooling unit is used to meet the temperature needs of the sampling unit and the separation unit. The sampling unit includes a dehydration tube and an enrichment tube. No breakthrough of the hydrocarbons was detected when the temperature of the enrichment tube was kept at -90 °C and sampling volume was 400 mL. The separation unit is a small round oven attached on the cooling column. A single capillary column (OV-1, 30 m × 0.32 mm I.D.) was used to separate the hydrocarbons. An optimal program temperature (-60 ∼ 170 °C) of the oven was achieved to efficiently separate C2-C12 hydrocarbons. There were good linear correlations (R(2)=0.993-0.999) between the signals of the hydrocarbons and the enrichment amount of hydrocarbons, and the relative standard deviation (RSD) was less than 5%, and the method detection limits (MDLs) for the hydrocarbons were in the range of 0.02-0.10 ppbv for sampling volume of 400 mL. Field measurements were also conducted and more than 50 hydrocarbons from C2 to C12 were detected in Beijing city. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Ground-based measurement of column-averaged mixing ratios of methane and carbon dioxide in the Sichuan Basin of China by a desktop optical spectrum analyzer

    Science.gov (United States)

    Qin, Xiu-Chun; Nakayama, Tomoki; Matsumi, Yutaka; Kawasaki, Masahiro; Ono, Akiko; Hayashida, Sachiko; Imasu, Ryoichi; Lei, Li-Ping; Murata, Isao; Kuroki, Takahiro; Ohashi, Masafumi

    2018-01-01

    Remote sensing of the atmospheric greenhouse gases, methane (CH4) and carbon dioxide (CO2), contributes to the understanding of global warming and climate change. A portable ground-based instrument consisting of a commercially available desktop optical spectrum analyzer and a small sun tracker has been applied to measure the column densities of atmospheric CH4 and CO2 at Yanting observation station in a mountainous paddy field of the Sichuan Basin from September to November 2013. The column-averaged dry-air molar mixing ratios, XCH4/XCO2, are compared with those retrieved by satellite observations in the Sichuan Basin and by ground-based network observations in the same latitude zone as the Yanting observation station.

  8. Off-axis Doas Measurements At Observatoire De Haute Provence During 2001

    Science.gov (United States)

    Roozendael, M. Van; de Mazière, M.; Fayt, C.; Hendrick, F.; Hermans, C.

    Since December 2000, a ground-based off-axis DOAS spectrometer has been operated by BIRA-IASB in the South of France at the Observatoire de Haute Provence (OHP, 44°N). The design of the instrument allows automated observations of the scattered light alternatively in the zenith direction and at 10° above the horizon (off-axis geometry). The spectrometer is polarised and follows the azimuth of the sun. Its temperature is regulated and it is equipped with a Princeton Instruments/ Hammamatsu cooled diode array detector. Observations are made every 5 minutes in the 320-390 nm range. The analysis of the spectra recorded between January and December 2001 demonstrates the sensitivity of the measurements to tropospheric contents of NO2, HCHO, O3 and BrO. Results show a large seasonality in the HCHO content with maximum values in summer. The tropospheric BrO column is found to be stable over the year in the range of approximately 1.5-2 x1013 molec/cm2, roughly consistent with GOME observations at Northern mid-latitudes. Large increases of the BrO concentration are observed in summer likely due to local pollution in the vicinity of the station.

  9. Impact of Different H/D Ratio on Axial Gas Holdup Measured by Four-Tips Optical Fiber Probe in Slurry Bubble Column

    Directory of Open Access Journals (Sweden)

    Yasser Imad Abdulaziz

    2016-02-01

    Full Text Available In wide range of chemical, petrochemical and energy processes, it is not possible to manage without slurry bubble column reactors. In this investigation, time average local gas holdup was recorded for three different height to diameter (H/D ratios 3, 4 and 5 in 18" diameter slurry bubble column. Air-water-glass beads system was used with superficial velocity up to 0.24 m/s. the gas holdup was measured using 4-tips optical fiber probe technique. The results show that the axial gas holdup increases almost linearly with the superficial gas velocity in 0.08 m/s and levels off with a further increase of velocity. A comparison of the present data with those reported for other slurry bubble column having diameters larger than 18" and H/D higher than 5 indicated that there is little effect of diameter on gas holdup. Also, local section-average gas holdups increase with increasing superficial gas velocity, while the effect of solid loading are less significant than that of superficial gas velocity.

  10. Spatio-temporal variations of nitric acid total columns from 9 years of IASI measurements - a driver study

    Science.gov (United States)

    Ronsmans, Gaétane; Wespes, Catherine; Hurtmans, Daniel; Clerbaux, Cathy; Coheur, Pierre-François

    2018-04-01

    This study aims to understand the spatial and temporal variability of HNO3 total columns in terms of explanatory variables. To achieve this, multiple linear regressions are used to fit satellite-derived time series of HNO3 daily averaged total columns. First, an analysis of the IASI 9-year time series (2008-2016) is conducted based on various equivalent latitude bands. The strong and systematic denitrification of the southern polar stratosphere is observed very clearly. It is also possible to distinguish, within the polar vortex, three regions which are differently affected by the denitrification. Three exceptional denitrification episodes in 2011, 2014 and 2016 are also observed in the Northern Hemisphere, due to unusually low arctic temperatures. The time series are then fitted by multivariate regressions to identify what variables are responsible for HNO3 variability in global distributions and time series, and to quantify their respective influence. Out of an ensemble of proxies (annual cycle, solar flux, quasi-biennial oscillation, multivariate ENSO index, Arctic and Antarctic oscillations and volume of polar stratospheric clouds), only the those defined as significant (p value dominance of annual variability in all latitudinal bands, which is related to specific chemistry and dynamics depending on the latitudes. We find that the polar stratospheric clouds (PSCs) also have a major influence in the polar regions, and that their inclusion in the model improves the correlation coefficients and the residuals. However, there is still a relatively large portion of HNO3 variability that remains unexplained by the model, especially in the intertropical regions, where factors not included in the regression model (such as vegetation fires or lightning) may be at play.

  11. A Low-Cost Miniaturized Laser Heterodyne Radiometer (Mini-LHR) for Near-ir Measurements of CO2 and CH4 in the Atmospheric Column

    Science.gov (United States)

    Steel, Emily Wilson

    2016-01-01

    The miniaturized laser heterodyne radiometer (mini-LHR) is a ground-based passive variation of a laser heterodyne radiometer that uses sunlight to measure absorption of CO2 andCH4 in the infrared. Sunlight is collected using collimation optics mounted to an AERONET sun tracker, modulated with a fiber switch and mixed with infrared laser light in a fast photoreciever.The amplitude of the resultant RF (radio frequency) beat signal correlates with the concentration of the gas in the atmospheric column.

  12. Tropospheric and total ozone columns over Paris (France measured using medium-resolution ground-based solar-absorption Fourier-transform infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    C. Viatte

    2011-10-01

    Full Text Available Ground-based Fourier-transform infrared (FTIR solar absorption spectroscopy is a powerful remote sensing technique providing information on the vertical distribution of various atmospheric constituents. This work presents the first evaluation of a mid-resolution ground-based FTIR to measure tropospheric ozone, independently of stratospheric ozone. This is demonstrated using a new atmospheric observatory (named OASIS for "Observations of the Atmosphere by Solar absorption Infrared Spectroscopy", installed in Créteil (France. The capacity of the technique to separate stratospheric and tropospheric ozone is demonstrated. Daily mean tropospheric ozone columns derived from the Infrared Atmospheric Sounding Interferometer (IASI and from OASIS measurements are compared for summer 2009 and a good agreement of −5.6 (±16.1 % is observed. Also, a qualitative comparison between in-situ surface ozone measurements and OASIS data reveals OASIS's capacity to monitor seasonal tropospheric ozone variations, as well as ozone pollution episodes in summer 2009 around Paris. Two extreme pollution events are identified (on the 1 July and 6 August 2009 for which ozone partial columns from OASIS and predictions from a regional air-quality model (CHIMERE are compared following strict criteria of temporal and spatial coincidence. An average bias of 0.2%, a mean square error deviation of 7.6%, and a correlation coefficient of 0.91 is found between CHIMERE and OASIS, demonstrating the potential of a mid-resolution FTIR instrument in ground-based solar absorption geometry for tropospheric ozone monitoring.

  13. Direct-injection HPLC method of measuring micafungin in human plasma using a novel hydrophobic/hydrophilic hybrid ODS column.

    Science.gov (United States)

    Uranishi, Hiroaki; Nakamura, Mitsuhiro; Nakamura, Hiroki; Ikeda, Yukari; Otsuka, Mayuko; Kato, Zenichiro; Tsuchiya, Teruo

    2011-04-15

    A direct-injection HPLC-based method has been developed for determining amounts of micafungin in human plasma using a novel hydrophobic/hydrophilic hybrid ODS column. The method is easy to perform and requires only 10 μL of a filtered plasma sample. The chromatographic separations were carried out with a gradient mode. The fluorescence detection wavelengths of excitation and emission were set at 273 nm and 464 nm, respectively. Retention times for micafungin and IS were 22.4 and 23.7 min, respectively. Micafungin and FR195743 (IS) peaks were completely separated with little tailing, and no interference was observed. The calibration curve of micafungin showed good linearity in the range of 0.5-20.0 μg/mL (r(2)=1.00). The intra-day accuracy ranged from -4.5 to 5.3%. The inter-day accuracy ranged from -9.8 to 1.5%. The precisions were less than 10%. This method is useful for the determination of micafungin in human plasma. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2017-12-01

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

  15. Total ozone column derived from GOME and SCIAMACHY using KNMI retrieval algorithms: Validation against Brewer measurements at the Iberian Peninsula

    Science.gov (United States)

    Antón, M.; Kroon, M.; López, M.; Vilaplana, J. M.; Bañón, M.; van der A, R.; Veefkind, J. P.; Stammes, P.; Alados-Arboledas, L.

    2011-11-01

    This article focuses on the validation of the total ozone column (TOC) data set acquired by the Global Ozone Monitoring Experiment (GOME) and the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) satellite remote sensing instruments using the Total Ozone Retrieval Scheme for the GOME Instrument Based on the Ozone Monitoring Instrument (TOGOMI) and Total Ozone Retrieval Scheme for the SCIAMACHY Instrument Based on the Ozone Monitoring Instrument (TOSOMI) retrieval algorithms developed by the Royal Netherlands Meteorological Institute. In this analysis, spatially colocated, daily averaged ground-based observations performed by five well-calibrated Brewer spectrophotometers at the Iberian Peninsula are used. The period of study runs from January 2004 to December 2009. The agreement between satellite and ground-based TOC data is excellent (R2 higher than 0.94). Nevertheless, the TOC data derived from both satellite instruments underestimate the ground-based data. On average, this underestimation is 1.1% for GOME and 1.3% for SCIAMACHY. The SCIAMACHY-Brewer TOC differences show a significant solar zenith angle (SZA) dependence which causes a systematic seasonal dependence. By contrast, GOME-Brewer TOC differences show no significant SZA dependence and hence no seasonality although processed with exactly the same algorithm. The satellite-Brewer TOC differences for the two satellite instruments show a clear and similar dependence on the viewing zenith angle under cloudy conditions. In addition, both the GOME-Brewer and SCIAMACHY-Brewer TOC differences reveal a very similar behavior with respect to the satellite cloud properties, being cloud fraction and cloud top pressure, which originate from the same cloud algorithm (Fast Retrieval Scheme for Clouds from the Oxygen A-Band (FRESCO+)) in both the TOSOMI and TOGOMI retrieval algorithms.

  16. Time-series measurements of bubble plume variability and water column methane distribution above Southern Hydrate Ridge, Oregon

    Science.gov (United States)

    Philip, Brendan T.; Denny, Alden R.; Solomon, Evan A.; Kelley, Deborah S.

    2016-03-01

    An estimated 500-2500 gigatons of methane carbon is sequestered in gas hydrate at continental margins and some of these deposits are associated with overlying methane seeps. To constrain the impact that seeps have on methane concentrations in overlying ocean waters and to characterize the bubble plumes that transport methane vertically into the ocean, water samples and time-series acoustic images were collected above Southern Hydrate Ridge (SHR), a well-studied hydrate-bearing seep site ˜90 km west of Newport, Oregon. These data were coregistered with robotic vehicle observations to determine the origin of the seeps, the plume rise heights above the seafloor, and the temporal variability in bubble emissions. Results show that the locations of seep activity and bubble release remained unchanged over the 3 year time-series investigation, however, the magnitude of gas release was highly variable on hourly time scales. Bubble plumes were detected to depths of 320-620 m below sea level (mbsl), in several cases exceeding the upper limit of hydrate stability by ˜190 m. For the first time, sustained gas release was imaged at the Pinnacle site and in-between the Pinnacle and the Summit area of venting, indicating that the subseafloor transport of fluid and gas is not restricted to the Summit at SHR, requiring a revision of fluid-flow models. Dissolved methane concentrations above background levels from 100 to 300 mbsl are consistent with long-term seep gas transport into the upper water column, which may lead to the build-up of seep-derived carbon in regional subsurface waters and to increases in associated biological activity.

  17. Spatial and Temporal Variability of Ground and Satellite Column Measurements of NO2 and O3 over the Atlantic Ocean During the Deposition of Atmospheric Nitrogen to Coastal Ecosystems Experiment

    Science.gov (United States)

    Martins, Douglas K.; Najjar, Raymond G.; Tzortziou, Maria; Abuhassan, Nader; Thompson, Anne M.; Kollonige, Debra E.

    2016-01-01

    In situ measurements of O3 and nitrogen oxides (NO + NO2=NOx) and remote sensing measurements of total column NO2 and O3 were collected on a ship in the North Atlantic Ocean as part of the Deposition of Atmospheric Nitrogen to Coastal Ecosystems (DANCE) campaign in July August 2014,100 km east of the mid-Atlantic United States. Relatively clean conditions for both surface in situ mixing ratio and total column O3 and NO2 measurements were observed throughout the campaign. Increased surface and column NO2 and O3 amounts were observed when a terrestrial air mass was advected over the study region. Relative to ship-based total column measurements using a Pandora over the entire study, satellite measurements overestimated total column NO2 under these relatively clean atmospheric conditions over offshore waters by an average of 16. Differences are most likely due to proximity, or lack thereof, to surface emissions; spatial averaging due to the field of view of the satellite instrument; and the lack of sensitivity of satellite measurements to the surface concentrations of pollutants. Total column O3 measurements from the shipboard Pandora showed good correlation with the satellite measurements(r 0.96), but satellite measurements were 3 systematically higher than the ship measurements, in agreement with previous studies. Derived values of boundary layer height using the surface in situ and total column measurements of NO2 are much lower than modeled and satellite-retrieved boundary layer heights, which highlight the differences in the vertical distribution between terrestrial and marine environments.

  18. High Precision, Absolute Total Column Ozone Measurements from the Pandora Spectrometer System: Comparisons with Data from a Brewer Double Monochromator and Aura OMI

    Science.gov (United States)

    Tzortziou, Maria A.; Herman, Jay R.; Cede, Alexander; Abuhassan, Nader

    2012-01-01

    We present new, high precision, high temporal resolution measurements of total column ozone (TCO) amounts derived from ground-based direct-sun irradiance measurements using our recently deployed Pandora single-grating spectrometers. Pandora's small size and portability allow deployment at multiple sites within an urban air-shed and development of a ground-based monitoring network for studying small-scale atmospheric dynamics, spatial heterogeneities in trace gas distribution, local pollution conditions, photochemical processes and interdependencies of ozone and its major precursors. Results are shown for four mid- to high-latitude sites where different Pandora instruments were used. Comparisons with a well calibrated double-grating Brewer spectrometer over a period of more than a year in Greenbelt MD showed excellent agreement and a small bias of approximately 2 DU (or, 0.6%). This was constant with slant column ozone amount over the full range of observed solar zenith angles (15-80), indicating adequate Pandora stray light correction. A small (1-2%) seasonal difference was found, consistent with sensitivity studies showing that the Pandora spectral fitting TCO retrieval has a temperature dependence of 1% per 3K, with an underestimation in temperature (e.g., during summer) resulting in an underestimation of TCO. Pandora agreed well with Aura-OMI (Ozone Measuring Instrument) satellite data, with average residuals of <1% at the different sites when the OMI view was within 50 km from the Pandora location and OMI-measured cloud fraction was <0.2. The frequent and continuous measurements by Pandora revealed significant short-term (hourly) temporal changes in TCO, not possible to capture by sun-synchronous satellites, such as OMI, alone.

  19. Photocatalytic removal of NO and HCHO over nanocrystalline Zn2SnO4 microcubes for indoor air purification

    International Nuclear Information System (INIS)

    Ai Zhihui; Lee Shuncheng; Huang Yu; Ho Wingkei; Zhang Lizhi

    2010-01-01

    Nanocrystalline Zn 2 SnO 4 microcubes were hydrothermally synthesized and systematically characterized by XRD, SEM, TEM, XPS, N 2 adsorption-desorption, and UV-vis DRS analysis. The resulting Zn 2 SnO 4 microcubes with the edge size ranging from 0.8 to 1.2 μm were composed of numerous nanoparticles with size of 10-20 nm, and their optical band gap energy was estimated to be 3.25 eV from the UV-vis diffuse reflectance spectra. On degradation of nitrogen monoxide (NO) and formaldehyde (HCHO) at typical concentrations for indoor air quality, these nanocrystalline Zn 2 SnO 4 microcubes exhibited superior photocatalytic activity to the hydrothermally synthesized ZnO, SnO 2 , and Degussa TiO 2 P25, as well as C doped TiO 2 under UV-vis light irradiation. This enhanced photocatalytic activity of the nanocrystalline Zn 2 SnO 4 microcubes was attributed to their bigger surface areas, smaller particle size, special porous structures, and special electronic configuration. The nanocrystalline Zn 2 SnO 4 microcubes were chemically stable as there was no obvious deactivation during the multiple photocatalytic reactions. This work presents a promising approach for scaling-up industrial production of Zn 2 SnO 4 nanostructures and suggests that the synthesized nanocrystalline Zn 2 SnO 4 microcubes are promising photocatalysts for indoor air purification.

  20. Assessment of a Technique for Estimating Total Column Water Vapor Using Measurements of the Infrared Sky Temperature

    Science.gov (United States)

    Merceret, Francis J.; Huddleston, Lisa L.

    2014-01-01

    A method for estimating the integrated precipitable water (IPW) content of the atmosphere using measurements of indicated infrared zenith sky temperature was validated over east-central Florida. The method uses inexpensive, commercial off the shelf, hand-held infrared thermometers (IRT). Two such IRTs were obtained from a commercial vendor, calibrated against several laboratory reference sources at KSC, and used to make IR zenith sky temperature measurements in the vicinity of KSC and Cape Canaveral Air Force Station (CCAFS). The calibration and comparison data showed that these inexpensive IRTs provided reliable, stable IR temperature measurements that were well correlated with the NOAA IPW observations.

  1. Using Performance Reference Compounds (PRCs) to measure dissolved water concentrations (Cfree) in the water column: Assessing equilibrium models

    Science.gov (United States)

    Equilibrium-based passive sampling methods are often used in aquatic environmental monitoring to measure hydrophobic organic contaminants (HOCs) and in the subsequent evaluation of their effects on ecological and human health. HOCs freely dissolved in water (Cfree) will partition...

  2. Modeling Stone Columns.

    Science.gov (United States)

    Castro, Jorge

    2017-07-11

    This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the "unit cell", longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

  3. Population inversion and gain measurements for soft x-ray-laser development in a magnetically confined plasma column

    International Nuclear Information System (INIS)

    Suckewer, S.; Skinner, C.H.; Voorhees, D.; Milchberg, H.; Keane, C.; Semet, A.

    1983-06-01

    We present population inversion and gain measurements from an experimental investigation of possibilities to obtain high gain and lasing action in the soft x-ray region. Our approach to soft x-ray-laser development is based on rapid plasma cooling after the laser pulse by radiation losses, leading to fast recombination and collisional cascade into upper excited levels of CVI, for example, while the lower excited levels depopulate rapidly by radiative transitions, thus creating population inversions and gain. A approx. = 0.5 kJ CO 2 laser was focused onto a target of solid carbon or teflon; or CO 2 , O 2 , Ne gas, and the resulting plasma confined in a 50 to 90 kG magnetic field. Spectroscopic diagnostics with absolute intensity calibration were used to measure level populations

  4. Column carbon dioxide and water vapor measurements by an airborne triple-pulse integrated path differential absorption lidar: novel lidar technologies and techniques with path to space

    Science.gov (United States)

    Singh, U. N.; Petros, M.; Refaat, T. F.; Yu, J.; Ismail, S.

    2017-09-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption features for the gas at this wavelength region [1]. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers [2]. Currently, LaRC team is engaged in designing, developing and demonstrating a triple-pulsed 2-micron direct detection Integrated Path Differential Absorption (IPDA) lidar to measure the weighted-average column dry-air mixing ratios of carbon dioxide (XCO2) and water vapor (XH2O) from an airborne platform [1, 3-5]. This novel technique allows measurement of the two most dominant greenhouse gases, simultaneously and independently, using a single instrument. This paper will provide status and details of the development of this airborne 2-micron triple-pulse IPDA lidar. The presented work will focus on the advancement of critical IPDA lidar components. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver and detector upgrades, laser packaging and lidar integration. Future plans for IPDA lidar ground integration, testing and flight validation will also be discussed. This work enables new Earth observation measurements, while reducing risk, cost, size, volume, mass and development time of required instruments.

  5. ( Anogeissus leiocarpus ) timber columns

    African Journals Online (AJOL)

    A procedure for designing axially loaded Ayin (Anogeissus leiocarpus) wood column or strut has been investigated. Instead of the usual categorization of columns into short, intermediate and slender according to the value of slenderness ratio, a continuous column formula representing the three categories was derived.

  6. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  7. In line digital holography measurement for liquid-liquid flow: application to the characterization of emulsions produced in pulsed column

    International Nuclear Information System (INIS)

    Lamadie, F.

    2013-01-01

    Several processes used in research and industry are based on liquid-liquid extraction, a method designed for selective separation of products in a mixture. In liquid-liquid extraction, two immiscible liquids are contacted: an aqueous phase and an organic phase, one of which generally contains an extractant molecule capable of transferring the desired elements to the other phase. The transfer occurs at the contact surface between the two phases. After transfer, both phases are separated by settling. In practice, these operations are performed in industrial apparatus. In order to optimize the operation of these devices, it's important to determine the fundamental characteristics of the emulsion. These include parameters related to the fluid flow velocity as well as parameters related to fluid mixing such as the interfacial area, hold-up, and size distribution of the droplets population. Numerous imaging techniques can be used to measure these parameters. One of them, digital holography, is well-known for allowing complete reconstruction of information about a 3D flow in a single shot. This PhD work deals with a direct application of digital in line holography to droplets rising in a continuous liquid phase. The droplet size imposes a regime of intermediate-field diffraction hardly explored to date. Acquired diffraction patterns show that the usual dark disk model is not valid and that good agreement is obtained with a mixed model coupling thin lens with opaque disk. Hologram focusing is nevertheless performed with a dedicated automated method. A literature review has been conducted to identify the sharpest auto-focus function for our application. In a second step, in order to measure high retention rates, an inverse problem approach is applied on all the outliers and missing droplets. This hologram restitution treatment has been applied to experimental results with a comparison to independent measurements. The main results obtained with calibrated droplets are

  8. A full-mission data set of H2O and HDO columns from SCIAMACHY 2.3 µm reflectance measurements

    Directory of Open Access Journals (Sweden)

    A. Schneider

    2018-06-01

    Full Text Available A new data set of vertical column densities of the water vapour isotopologues H2O and HDO from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY instrument for the whole of the mission period from January 2003 to April 2012 is presented. The data are retrieved from reflectance measurements in the spectral range 2339 to 2383 nm with the Shortwave Infrared CO Retrieval (SICOR algorithm, ignoring atmospheric light scattering in the measurement simulation. The retrievals are validated with ground-based Fourier transform infrared measurements obtained within the Multi-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA project. A good agreement for low-altitude stations is found with an average bias of −3.6×1021 for H2O and −1.0×1018 molec cm−2 for HDO. The a posteriori computed δD shows an average bias of −8 ‰, even though polar stations have a larger negative bias. The latter is due to the large amount of sensor noise in SCIAMACHY in combination with low albedo and high solar zenith angles. To demonstrate the benefit of accounting for light scattering in the retrieval, the quality of the data product fitting effective cloud parameters simultaneously with trace gas columns is evaluated in a dedicated case study for measurements round high-altitude stations. Due to a large altitude difference between the satellite ground pixel and the mountain station, clear-sky scenes yield a large bias, resulting in a δD bias of 125 ‰. When selecting scenes with optically thick clouds within 1000 m above or below the station altitude, the bias in a posteriori δD is reduced from 125 to 44 ‰. The insights from the present study will also benefit the analysis of the data from the new Sentinel-5 Precursor mission.

  9. The total column of CO2 and CH4 measured with a compact Fourier transform spectrometer at NASA Armstrong Flight Research Center and Railroad Valley, Nevada, USA

    Science.gov (United States)

    Kawakami, S.; Shiomi, K.; Suto, H.; Kuze, A.; Hillyard, P. W.; Tanaka, T.; Podolske, J. R.; Iraci, L. T.; Albertson, R. T.

    2014-12-01

    The total columns of carbon dioxide (XCO2) and methane (XCH4) were measured with a compact Fourier transform spectrometer (FTS) at NASA Armstrong Flight Research Center (AFRC) and Railroad Valley, Nevada, USA (RRV) during a vicarious calibration campaign in June 2014. The campaign was performed to estimate changes in the radiometric response of the Thermal and Near Infrared Sensor for carbon Observations Fourier Transform Spectrometer (TANSO-FTS) and the Cloud and Aerosol Imager (TANSO-CAI) aboard Greenhouse gases Observing SATellite (GOSAT). TANSO-FTS measures spectra of radiance scattered by the Earth surface with high- and medium-gain depending on the surface reflectance. At high reflectance areas, such as deserts over north Africa and Australia, TANSO-FTS collects spectra with medium-gain. There was differences on atmospheric pressure and XCO2 retrieved from spectra obtained between high-gain and medium-gain. Because the retrieved products are useful for evaluating the difference of spectral qualities between high- and medium-gain, this work is an attempt to collect validation data for spectra with medium-gain of TANSO-FTS at remote and desert area with a compact and medium-spectral resolution instrument. As a compact FTS, EM27/SUN was used. It was manufactured and newly released on April 1, 2014 by Bruker. It is robust and operable in a high temperature environment. It was housed in a steel box to protect from dust and rain and powered by Solar panels. It can be operated by such a remote and desert area, like a RRV. Over AFRC and RRV, vertical profiles of CO2 and CH4 were measured using the Alpha Jet research aircraft as part of the Alpha Jet Atmospheric eXperiment (AJAX) of ARC, NASA. The values were calibrated to standard gases. To make the results comparable to WMO (World Meteorological Organization) standards, the retrieved XCO2 and XCH4 values are divided by a calibration factor. This values were determined by comparisons with in situ profiles measured by

  10. A hollow-waveguide gas correlation radiometer for ultra-precise column measurements of formaldehyde on Mars

    International Nuclear Information System (INIS)

    Wilson, Emily L; Riris, Haris; Heaps, William S; Neveu, Marc; Georgieva, Elena M

    2011-01-01

    We present preliminary results in the development of a miniaturized gas correlation radiometer that implements a hollow-core optical fiber (hollow-waveguide) gas correlation cell. The substantial reduction in mass and volume of the gas correlation cell makes this technology appropriate for an orbital mission—capable of pinpointing sources of trace gases in the Martian atmosphere. Here, we demonstrate a formaldehyde (H 2 CO) sensor and report a detection limit equivalent to ∼30 ppb in the Martian atmosphere. The relative simplicity of the technique allows it to be expanded to measure a range of atmospheric trace gases of interest on Mars such as methane (CH 4 ), water vapor (H 2 O), deuterated water vapor (HDO), and methanol (CH 3 OH). Performance of a formaldehyde instrument in a Mars orbit has been simulated assuming a 3 m long, 1000 µm inner diameter hollow-core fiber gas correlation cell, a 92.8° sun-synchronous orbit from 400 km with a horizontal sampling scale of 10 km × 10 km. Initial results indicate that for 1 s of averaging, a detection limit of 1 ppb is possible

  11. NOx retention in scrubbing column

    International Nuclear Information System (INIS)

    Nakazone, A.K.; Costa, R.E.; Lobao, A.S.T.; Matsuda, H.T.; Araujo, B.F.

    1988-07-01

    During the UO 2 dissolution in nitric acid, some different species of NO x are released. The off gas can either be refluxed to the dissolver or be released and retained on special columns. The final composition of the solution is the main parameter to take in account. A process for nitrous gases retention using scubber columns containing H 2 O or diluted HNO 3 is presented. Chemiluminescence measurement was employed to NO x evalution before and after scrubbing. Gas flow, temperature, residence time are the main parameters considered in this paper. For the dissolution of 100g UO 2 in 8M nitric acid, a 6NL/h O 2 flow was the best condition for the NO/NO 2 oxidation with maximum adsorption in the scrubber columns. (author) [pt

  12. Influence of stratospheric airmasses on tropospheric vertical O3 columns based on GOME (Global Ozone Monitoring Experiment measurements and backtrajectory calculation over the Pacific

    Directory of Open Access Journals (Sweden)

    A. Ladstätter-Weißenmayer

    2004-01-01

    Full Text Available Satellite based GOME (Global Ozone Measuring experiment data are used to characterize the amount of tropospheric ozone over the tropical Pacific. Tropospheric ozone was determined from GOME data using the Tropospheric Excess Method (TEM. In the tropical Pacific a significant seasonal variation is detected. Tropospheric excess ozone is enhanced during the biomass burning season from September to November due to outflow from the continents. In September 1999 GOME data reveal an episode of increased excess ozone columns over Tahiti (18.0° S; 149.0° W (Eastern Pacific compared to Am. Samoa (14.23° S; 170.56° W and Fiji (18.13° S; 178.40° E, both situated in the Western Pacific. Backtrajectory calculations show that none of the airmasses arriving over the three locations experienced anthropogenic pollution (e. g. biomass burning. Consequently other sources of ozone have to be considered. One possible process leading to an increase of tropospheric ozone is stratosphere-troposphere-exchange. An analysis of the potential vorticity along trajectories arriving above each of the locations reveals that airmasses at Tahiti are subject to enhanced stratospheric influence, compared to Am. Samoa and Fiji. As a result this study shows clear incidents of transport of airmasses from the stratosphere into the troposphere.

  13. Small Column Ion Exchange

    International Nuclear Information System (INIS)

    Huff, Thomas

    2010-01-01

    Small Column Ion Exchange (SCIX) leverages a suite of technologies developed by DOE across the complex to achieve lifecycle savings. Technologies are applicable to multiple sites. Early testing supported multiple sites. Balance of SRS SCIX testing supports SRS deployment. A forma Systems Engineering Evaluation (SEE) was performed and selected Small Column Ion Exchange columns containing Crystalline Silicotitanate (CST) in a 2-column lead/lag configuration. SEE considered use of Spherical Resorcinol-Formaldehyde (sRF). Advantages of approach at SRS include: (1) no new buildings, (2) low volume of Cs waste in solid form compared to aqueous strip effluent; and availability of downstream processing facilities for immediate processing of spent resin.

  14. A Laboratory Experiment To Measure Henry's Law Constants of Volatile Organic Compounds with a Bubble Column and a Gas Chromatography Flame Ionization Detector (GC-FID)

    Science.gov (United States)

    Lee, Shan-Hu; Mukherjee, Souptik; Brewer, Brittany; Ryan, Raphael; Yu, Huan; Gangoda, Mahinda

    2013-01-01

    An undergraduate laboratory experiment is described to measure Henry's law constants of organic compounds using a bubble column and gas chromatography flame ionization detector (GC-FID). This experiment is designed for upper-division undergraduate laboratory courses and can be implemented in conjunction with physical chemistry, analytical…

  15. Optimization and simulation of tandem column supercritical fluid chromatography separations using column back pressure as a unique parameter.

    Science.gov (United States)

    Wang, Chunlei; Tymiak, Adrienne A; Zhang, Yingru

    2014-04-15

    Tandem column supercritical fluid chromatography (SFC) has demonstrated to be a useful technique to resolve complex mixtures by serially coupling two columns of different selectivity. The overall selectivity of a tandem column separation is the retention time weighted average of selectivity from each coupled column. Currently, the method development merely relies on extensive screenings and is often a hit-or-miss process. No attention is paid to independently adjust retention and selectivity contributions from individual columns. In this study, we show how tandem column SFC selectivity can be optimized by changing relative dimensions (length or inner diameter) of the coupled columns. Moreover, we apply column back pressure as a unique parameter for SFC optimization. Continuous tuning of tandem column SFC selectivity is illustrated through column back pressure adjustments of the upstream column, for the first time. In addition, we show how and why changing coupling order of the columns can produce dramatically different separations. Using the empirical mathematical equation derived in our previous study, we also demonstrate a simulation of tandem column separations based on a single retention time measurement on each column. The simulation compares well with experimental results and correctly predicts column order and back pressure effects on the separations. Finally, considerations on instrument and column hardware requirements are discussed.

  16. JCE Feature Columns

    Science.gov (United States)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  17. Nuclear reactor control column

    International Nuclear Information System (INIS)

    Bachovchin, D.M.

    1982-01-01

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor

  18. Improvements in solvent extraction columns

    International Nuclear Information System (INIS)

    Aughwane, K.R.

    1987-01-01

    Solvent extraction columns are used in the reprocessing of irradiated nuclear fuel. For an effective reprocessing operation a solvent extraction column is required which is capable of distributing the feed over most of the column. The patent describes improvements in solvent extractions columns which allows the feed to be distributed over an increased length of column than was previously possible. (U.K.)

  19. Effects of GC temperature and carrier gas flow rate on on-line oxygen isotope measurement as studied by on-column CO injection.

    Science.gov (United States)

    Chen, Zhi-Gang; Yin, Xi-Jie; Zhou, Youping

    2015-08-01

    Although deemed important to δ 18 O measurement by on-line high-temperature conversion techniques, how the GC conditions affect δ 18 O measurement is rarely examined adequately. We therefore directly injected different volumes of CO or CO-N 2 mix onto the GC column by a six-port valve and examined the CO yield, CO peak shape, CO-N 2 separation, and δ 18 O value under different GC temperatures and carrier gas flow rates. The results show the CO peak area decreases when the carrier gas flow rate increases. The GC temperature has no effect on peak area. The peak width increases with the increase of CO injection volume but decreases with the increase of GC temperature and carrier gas flow rate. The peak intensity increases with the increase of GC temperature and CO injection volume but decreases with the increase of carrier gas flow rate. The peak separation time between N 2 and CO decreases with an increase of GC temperature and carrier gas flow rate. δ 18 O value decreases with the increase of CO injection volume (when half m/z 28 intensity is rate. On average, the δ 18 O value of the injected CO is about 1‰ higher than that of identical reference CO. The δ 18 O distribution pattern of the injected CO is probably a combined result of ion source nonlinearity and preferential loss of C 16 O or oxygen isotopic exchange between zeolite and CO. For practical application, a lower carrier gas flow rate is therefore recommended as it has the combined advantages of higher CO yield, better N 2 -CO separation, lower He consumption, and insignificant effect on δ 18 O value, while a higher-than-60 °C GC temperature and a larger-than-100 µl CO volume is also recommended. When no N 2 peak is expected, a higher GC temperature is recommended, and vice versa. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Buckling of liquid columns

    NARCIS (Netherlands)

    Habibi, M.; Rahmani, Y.; Bonn, D.; Ribe, N.M.

    2010-01-01

    Under appropriate conditions, a column of viscous liquid falling onto a rigid surface undergoes a buckling instability. Here we show experimentally and theoretically that liquid buckling exhibits a hitherto unsuspected complexity involving three different modes—viscous, gravitational, and

  1. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.

    1979-01-01

    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  2. Studies of column supported towers

    International Nuclear Information System (INIS)

    Chauvel, D.; Costaz, J.-L.

    1991-01-01

    As a result of a research and development programme into the civil engineering of cooling towers launched in 1978 by Electricite de France, very high cooling towers were built at Golfech and Chooz, in France, using column supports. This paper discusses the evolution of this new type of support from classical diagonal supports, presents some of the results of design calculations and survey measurements taken during construction of the shell and analyses the behaviour of the structure. (author)

  3. First direct measurements of formaldehyde flux via eddy covariance: implications for missing in-canopy formaldehyde sources

    Directory of Open Access Journals (Sweden)

    J. P. DiGangi

    2011-10-01

    Full Text Available We report the first observations of formaldehyde (HCHO flux measured via eddy covariance, as well as HCHO concentrations and gradients, as observed by the Madison Fiber Laser-Induced Fluorescence Instrument during the BEACHON-ROCS 2010 campaign in a rural, Ponderosa Pine forest northwest of Colorado Springs, CO. A median noon upward flux of ~80 μg m−2 h−1 (~24 pptv m s−1 was observed with a noon range of 37 to 131 μg m−2 h−1. Enclosure experiments were performed to determine the HCHO branch (3.5 μg m-2 h−1 and soil (7.3 μg m−2 h−1 direct emission rates in the canopy. A zero-dimensional canopy box model, used to determine the apportionment of HCHO source and sink contributions to the flux, underpredicted the observed HCHO flux by a factor of 6. Simulated increases in concentrations of species similar to monoterpenes resulted in poor agreement with measurements, while simulated increases in direct HCHO emissions and/or concentrations of species similar to 2-methyl-3-buten-2-ol best improved model/measurement agreement. Given the typical diurnal variability of these BVOC emissions and direct HCHO emissions, this suggests that the source of the missing flux is a process with both a strong temperature and radiation dependence.

  4. Elastic oscillations of water column in the 2003 Tokachi-oki tsunami source: in-situ measurements and 3-D numerical modelling

    Directory of Open Access Journals (Sweden)

    M. A. Nosov

    2007-01-01

    Full Text Available During the 2003 Tokachi-Oki tsunamigenic earthquake the real-time JAMSTEC observatory obtained records which provided a unique opportunity to have a look deep inside the tsunami source. Considering water column as a compressible medium we processed the bottom pressure records in order to estimate amplitude, duration and velocity of bottom displacement. Spectral analysis of the records revealed a clear manifestation of the low-frequency elastic oscillations of water column. We also presented 3-D finite-difference numerical model developed in the framework of linear potential theory of ideal compressible fluid to better understand dynamical processes in the tsunami source. The model reproduces position of the main spectral maximum rather correctly. However, due to neglecting of crust elasticity and to lack of exact knowledge of spatiotemporal laws of bottom motion, there is an essential difference between in-situ observed and computed spectra.

  5. Admittance Scanning for Whole Column Detection.

    Science.gov (United States)

    Stamos, Brian N; Dasgupta, Purnendu K; Ohira, Shin-Ichi

    2017-07-05

    Whole column detection (WCD) is as old as chromatography itself. WCD requires an ability to interrogate column contents from the outside. Other than the obvious case of optical detection through a transparent column, admittance (often termed contactless conductance) measurements can also sense changes in the column contents (especially ionic content) from the outside without galvanic contact with the solution. We propose here electromechanically scanned admittance imaging and apply this to open tubular (OT) chromatography. The detector scans across the column; the length resolution depends on the scanning velocity and the data acquisition frequency, ultimately limited by the physical step resolution (40 μm in the present setup). Precision equal to this step resolution was observed for locating an interface between two immiscible liquids inside a 21 μm capillary. Mechanically, the maximum scanning speed was 100 mm/s, but at 1 kHz sampling rate and a time constant of 25 ms, the highest practical scan speed (no peak distortion) was 28 mm/s. At scanning speeds of 0, 4, and 28 mm/s, the S/N for 180 pL (zone length of 1.9 mm in a 11 μm i.d. column) of 500 μM KCl injected into water was 6450, 3850, and 1500, respectively. To facilitate constant and reproducible contact with the column regardless of minor variations in outer diameter, a double quadrupole electrode system was developed. Columns of significant length (>1 m) can be readily scanned. We demonstrate its applicability with both OT and commercial packed columns and explore uniformity of retention along a column, increasing S/N by stopped-flow repeat scans, etc. as unique applications.

  6. Geophysical validation and long-term consistency between GOME-2/MetOp-A total ozone column and measurements from the sensors GOME/ERS-2, SCIAMACHY/ENVISAT and OMI/Aura

    Directory of Open Access Journals (Sweden)

    M. E. Koukouli

    2012-09-01

    Full Text Available The main aim of the paper is to assess the consistency of five years of Global Ozone Monitoring Experiment-2/Metop-A [GOME-2] total ozone columns and the long-term total ozone satellite monitoring database already in existence through an extensive inter-comparison and validation exercise using as reference Brewer and Dobson ground-based measurements. The behaviour of the GOME-2 measurements is being weighed against that of GOME (1995–2011, Ozone Monitoring Experiment [OMI] (since 2004 and the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY [SCIAMACHY] (since 2002 total ozone column products. Over the background truth of the ground-based measurements, the total ozone columns are inter-evaluated using a suite of established validation techniques; the GOME-2 time series follow the same patterns as those observed by the other satellite sensors. In particular, on average, GOME-2 data underestimate GOME data by about 0.80%, and underestimate SCIAMACHY data by 0.37% with no seasonal dependence of the differences between GOME-2, GOME and SCIAMACHY. The latter is expected since the three datasets are based on similar DOAS algorithms. This underestimation of GOME-2 is within the uncertainty of the reference data used in the comparisons. Compared to the OMI sensor, on average GOME-2 data underestimate OMI_DOAS (collection 3 data by 1.28%, without any significant seasonal dependence of the differences between them. The lack of seasonality might be expected since both the GOME data processor [GDP] 4.4 and OMI_DOAS are DOAS-type algorithms and both consider the variability of the stratospheric temperatures in their retrievals. Compared to the OMI_TOMS (collection 3 data, no bias was found. We hence conclude that the GOME-2 total ozone columns are well suitable to continue the long-term global total ozone record with the accuracy needed for climate monitoring studies.

  7. Assembly for connecting the column ends of two capillary columns

    International Nuclear Information System (INIS)

    Kolb, B.; Auer, M.; Pospisil, P.

    1984-01-01

    In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

  8. MAX-DOAS measurements of HONO slant column densities during the MAD-CAT campaign: inter-comparison, sensitivity studies on spectral analysis settings, and error budget

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2017-10-01

    Full Text Available In order to promote the development of the passive DOAS technique the Multi Axis DOAS – Comparison campaign for Aerosols and Trace gases (MAD-CAT was held at the Max Planck Institute for Chemistry in Mainz, Germany, from June to October 2013. Here, we systematically compare the differential slant column densities (dSCDs of nitrous acid (HONO derived from measurements of seven different instruments. We also compare the tropospheric difference of SCDs (delta SCD of HONO, namely the difference of the SCDs for the non-zenith observations and the zenith observation of the same elevation sequence. Different research groups analysed the spectra from their own instruments using their individual fit software. All the fit errors of HONO dSCDs from the instruments with cooled large-size detectors are mostly in the range of 0.1 to 0.3  ×  1015 molecules cm−2 for an integration time of 1 min. The fit error for the mini MAX-DOAS is around 0.7  ×  1015 molecules cm−2. Although the HONO delta SCDs are normally smaller than 6  ×  1015 molecules cm−2, consistent time series of HONO delta SCDs are retrieved from the measurements of different instruments. Both fits with a sequential Fraunhofer reference spectrum (FRS and a daily noon FRS lead to similar consistency. Apart from the mini-MAX-DOAS, the systematic absolute differences of HONO delta SCDs between the instruments are smaller than 0.63  ×  1015 molecules cm−2. The correlation coefficients are higher than 0.7 and the slopes of linear regressions deviate from unity by less than 16 % for the elevation angle of 1°. The correlations decrease with an increase in elevation angle. All the participants also analysed synthetic spectra using the same baseline DOAS settings to evaluate the systematic errors of HONO results from their respective fit programs. In general the errors are smaller than 0.3  ×  1015 molecules cm−2, which is

  9. Atmospheric implications of simultaneous nighttime measurements of NO3 radicals and hono

    International Nuclear Information System (INIS)

    Pitts, J.N. Jr.; Biermann, H.W.; Atkinson, R.; Winer, A.M.

    1984-01-01

    Atmospheric concentrations of gaseous HONO and the NO 3 radical were measured simultaneously for the first time using long path differential optical absorption spectroscopy. Diurnal profiles are reported for two successive nights following days of moderate pollution at Riverside, California, together with concurrent measurements of NO 2 , O 3 and NO concentrations and an upper limit for HCHO levels. These measurements permit an examination of selected aspects of the nighttime atmospheric chemistry of HONO and the NO 3 radical and related species. Our data do not support a recently proposed homogeneous gas phase mechanism for HONO formation initiated by the reaction of the NO 3 radical with HCHO

  10. Columns in Clay

    Science.gov (United States)

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  11. Slender CRC Columns

    DEFF Research Database (Denmark)

    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter

    2005-01-01

    CRC is a high-performance steel fibre reinforced concrete with a typical compressive strength of 150 MPa. Design methods for a number of structural elements have been developed since CRC was invented in 1986, but the current project set out to further investigate the range of columns for which...

  12. Practical column design guide

    CERN Document Server

    Nitsche, M

    2017-01-01

    This book highlights the aspects that need to be considered when designing distillation columns in practice. It discusses the influencing parameters as well as the equations governing them, and presents several numerical examples. The book is intended both for experienced designers and for those who are new to the subject.

  13. Formaldehyde measurements by Proton transfer reaction – Mass Spectrometry (PTR-MS: correction for humidity effects

    Directory of Open Access Journals (Sweden)

    A. Vlasenko

    2010-08-01

    Full Text Available Formaldehyde measurements can provide useful information about photochemical activity in ambient air, given that HCHO is formed via numerous oxidation processes. Proton transfer reaction mass spectrometry (PTR-MS is an online technique that allows measurement of VOCs at the sub-ppbv level with good time resolution. PTR-MS quantification of HCHO is hampered by the humidity dependence of the instrument sensitivity, with higher humidity leading to loss of PTR-MS signal. In this study we present an analytical, first principles approach to correct the PTR-MS HCHO signal according to the concentration of water vapor in sampled air. The results of the correction are validated by comparison of the PTR-MS results to those from a Hantzsch fluorescence monitor which does not have the same humidity dependence. Results are presented for an intercomparison made during a field campaign in rural Ontario at Environment Canada's Centre for Atmospheric Research Experiments.

  14. PRTR ion exchange vault column sampling

    International Nuclear Information System (INIS)

    Cornwell, B.C.

    1995-01-01

    This report documents ion exchange column sampling and Non Destructive Assay (NDA) results from activities in 1994, for the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. The objective was to obtain sufficient information to prepare disposal documentation for the ion exchange columns found in the PRTR Ion exchange vault. This activity also allowed for the monitoring of the liquid level in the lower vault. The sampling activity contained five separate activities: (1) Sampling an ion exchange column and analyzing the ion exchange media for purpose of waste disposal; (2) Gamma and neutron NDA testing on ion exchange columns located in the upper vault; (3) Lower vault liquid level measurement; (4) Radiological survey of the upper vault; and (5) Secure the vault pending waste disposal

  15. Interpretation of the lime column penetration test

    International Nuclear Information System (INIS)

    Liyanapathirana, D S; Kelly, R B

    2010-01-01

    Dry soil mix (DSM) columns are used to reduce the settlement and to improve the stability of embankments constructed on soft clays. During construction the shear strength of the columns needs to be confirmed for compliance with technical assumptions. A specialized blade shaped penetrometer known as the lime column probe, has been developed for testing DSM columns. This test can be carried out as a pull out resistance test (PORT) or a push in resistance test (PIRT). The test is considered to be more representative of average column shear strength than methods that test only a limited area of the column. Both PORT and PIRT tests require empirical correlations of measured resistance to an absolute measure of shear strength, in a similar manner to the cone penetration test. In this paper, finite element method is used to assess the probe factor, N, for the PORT test. Due to the large soil deformations around the probe, an Arbitrary Lagrangian Eulerian (ALE) based finite element formulation has been used. Variation of N with rigidity index and the friction at the probe-soil interface are investigated to establish a range for the probe factor.

  16. Plasma L-ergothioneine measurement by high-performance liquid chromatography and capillary electrophoresis after a pre-column derivatization with 5-iodoacetamidofluorescein (5-IAF) and fluorescence detection.

    Science.gov (United States)

    Sotgia, Salvatore; Pisanu, Elisabetta; Pintus, Gianfranco; Erre, Gian Luca; Pinna, Gerard Aime; Deiana, Luca; Carru, Ciriaco; Zinellu, Angelo

    2013-01-01

    Two sensitive and reproducible capillary electrophoresis and high-performance liquid chromatography-fluorescence procedures were established for quantitative determination of L-egothioneine in plasma. After derivatization of L-ergothioneine with 5-iodoacetamidofluorescein, the separation was carried out by HPLC on an ODS-2 C-18 sperisorb column by using a linear gradient elution and by HPCE on an uncoated fused silica capillary, 50 µm id, and 60 cm length. The methods were validated and found to be linear in the range of 0.3 to 10 µmol/l. The limit of quantification was 0.27 µmol/l for HPCE and 0.15 µmol/l for HPLC. The variations for intra- and inter-assay precision were around 6 RSD%, and the mean recovery accuracy close to 100% (96.11%).

  17. A new method to detect long term trends of methane (CH4 and nitrous oxide (N2O total columns measured within the NDACC ground-based high resolution solar FTIR network

    Directory of Open Access Journals (Sweden)

    M. Schneider

    2011-07-01

    Full Text Available Total columns measured with the ground-based solar FTIR technique are highly variable in time due to atmospheric chemistry and dynamics in the atmosphere above the measurement station. In this paper, a multiple regression model with anomalies of air pressure, total columns of hydrogen fluoride (HF and carbon monoxide (CO and tropopause height are used to reduce the variability in the methane (CH4 and nitrous oxide (N2O total columns to estimate reliable linear trends with as small uncertainties as possible. The method is developed at the Harestua station (60° N, 11° E, 600 m a.s.l. and used on three other European FTIR stations, i.e. Jungfraujoch (47° N, 8° E, 3600 m a.s.l., Zugspitze (47° N, 11° E, 3000 m a.s.l., and Kiruna (68° N, 20° E, 400 m a.s.l.. Linear CH4 trends between 0.13 ± 0.01-0.25 ± 0.02 % yr−1 were estimated for all stations in the 1996-2009 period. A piecewise model with three separate linear trends, connected at change points, was used to estimate the short term fluctuations in the CH4 total columns. This model shows a growth in 1996–1999 followed by a period of steady state until 2007. From 2007 until 2009 the atmospheric CH4 amount increases between 0.57 ± 0.22–1.15 ± 0.17 % yr−1. Linear N2O trends between 0.19 ± 0.01–0.40 ± 0.02 % yr−1 were estimated for all stations in the 1996-2007 period, here with the strongest trend at Harestua and Kiruna and the lowest at the Alp stations. From the N2O total columns crude tropospheric and stratospheric partial columns were derived, indicating that the observed difference in the N2O trends between the FTIR sites is of stratospheric origin. This agrees well with the N2O measurements by the SMR instrument onboard the Odin satellite showing the highest trends at Harestua, 0.98 ± 0.28 % yr−1, and considerably smaller trends at lower latitudes, 0.27 ± 0.25 % yr−1. The multiple regression model was compared with two other trend methods, the ordinary linear

  18. Nine Words - Nine Columns

    DEFF Research Database (Denmark)

    Trempe Jr., Robert B.; Buthke, Jan

    2016-01-01

    This book records the efforts of a one-week joint workshop between Master students from Studio 2B of Arkitektskolen Aarhus and Master students from the Harbin Institute of Technology in Harbin, China. The workshop employed nine action words to instigate team-based investigation into the effects o...... as formwork for the shaping of wood veneer. The resulting columns ‘wear’ every aspect of this design pipeline process and display the power of process towards an architectural resolution....

  19. NMFS Water Column Sonar Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water column sonar data are an important component of fishery independent surveys, habitat studies and other research. NMFS water column sonar data are archived here.

  20. Single column and two-column H-D-T distillation experiments at TSTA

    International Nuclear Information System (INIS)

    Yamanishi, T.; Yoshida, H.; Hirata, S.; Naito, T.; Naruse, Y.; Sherman, R.H.; Bartlit, J.R.; Anderson, J.L.

    1988-01-01

    Cryogenic distillation experiments were peformed at TSTA with H-D-T system by using a single column and a two-column cascade. In the single column experiment, fundamental engineering data such as the liquid holdup and the HETP were measured under a variety of operational condtions. The liquid holdup in the packed section was about 10 /approximately/ 15% of its superficial volume. The HETP values were from 4 to 6 cm, and increased slightly with the vapor velocity. The reflux ratio had no effect on the HETP. For the wo-colunn experiemnt, dynamic behavior of the cascade was observed. 8 refs., 7 figs., 2 tabs

  1. Elevator frames two columns

    OpenAIRE

    Marín Jiménez, Juan Francisco

    2015-01-01

    This project aims to solve the problem of vertical transport of charges raised by a company with the standard UNE 58-132-91/6. The purpose of this project is the industrial design of a system of load handling by a bi-columned lifting device, tractioned by flat belts and steel cables from a transport level to a different level in order to connect two different assembly lines situated at different heights. The goal of this project is lifting a 780 Kg load at a 2.400 mm height....

  2. Column: Every Last Byte

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-06-01

    Full Text Available Inheritance powder is the name that was given to poisons, especially arsenic, that were commonly used in the 17th and early 18th centuries to hasten the death of the elderly. For most of the 17th century, arsenic was deadly but undetectable, making it nearly impossible to prove that someone had been poisoned. The first arsenic test produced a gas—hardly something that a scientist could show to a judge. Faced with a growing epidemic of poisonings, doctors and chemists spent decades searching for something better.(see PDF for full column

  3. Annular pulse column development studies

    International Nuclear Information System (INIS)

    Benedict, G.E.

    1980-01-01

    The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein. The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases. The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other

  4. Influence of pressure on the properties of chromatographic columns. II. The column hold-up volume.

    Science.gov (United States)

    Gritti, Fabrice; Martin, Michel; Guiochon, Georges

    2005-04-08

    The effect of the local pressure and of the average column pressure on the hold-up column volume was investigated between 1 and 400 bar, from a theoretical and an experimental point of view. Calculations based upon the elasticity of the solids involved (column wall and packing material) and the compressibility of the liquid phase show that the increase of the column hold-up volume with increasing pressure that is observed is correlated with (in order of decreasing importance): (1) the compressibility of the mobile phase (+1 to 5%); (2) in RPLC, the compressibility of the C18-bonded layer on the surface of the silica (+0.5 to 1%); and (3) the expansion of the column tube (columns packed with the pure Resolve silica (0% carbon), the derivatized Resolve-C18 (10% carbon) and the Symmetry-C18 (20% carbon) adsorbents, using water, methanol, or n-pentane as the mobile phase. These solvents have different compressibilities. However, 1% of the relative increase of the column hold-up volume that was observed when the pressure was raised is not accounted for by the compressibilities of either the solvent or the C18-bonded phase. It is due to the influence of the pressure on the retention behavior of thiourea, the compound used as tracer to measure the hold-up volume.

  5. Column: File Cabinet Forensics

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-12-01

    Full Text Available Researchers can spend their time reverse engineering, performing reverse analysis, or making substantive contributions to digital forensics science. Although work in all of these areas is important, it is the scientific breakthroughs that are the most critical for addressing the challenges that we face.Reverse Engineering is the traditional bread-and-butter of digital forensics research. Companies like Microsoft and Apple deliver computational artifacts (operating systems, applications and phones to the commercial market. These artifacts are bought and used by billions. Some have evil intent, and (if society is lucky, the computers end up in the hands of law enforcement. Unfortunately the original vendors rarely provide digital forensics tools that make their systems amenable to analysis by law enforcement. Hence the need for reverse engineering.(see PDF for full column

  6. Intercomparison of slant column measurements of NO₂ and O₄ by MAX-DOAS and zenith-sky UV and visible spectrometers

    NARCIS (Netherlands)

    Roscoe, H.K.; Roozendael, Van M.; Fayt, C.; Piesanie, du A.; Abuhassan, N.; Adams, C.; Akrami, M.; Cede, A.; Chong, J.; Clémer, K.; Friess, U.; Gil Ojeda, M.; Goutail, F.; Graves, R.; Griesfeller, A.; Grossmann, K.; Hemerijckx, G.; Hendrick, F.; Herman, J.; Hermans, C.; Irie, H.; Johnston, P.V.; Kanaya, Y.; Kreher, K.; Leigh, R.; Merlaud, A.; Mount, G.H.; Navarro, M.; Oetjen, H.; Pazmino, A.; Perez-Camacho, M.; Peters, E.; Pinardi, G.; Puentedura, O.; Richter, A.; Schönhardt, A.; Shaiganfar, R.; Spinei, E.; Strong, K.; Takashima, H.; Vlemmix, T.; Vrekoussis, M.; Wagner, T.; Wittrock, F.; Yela, M.; Yilmaz, S.S.; Boersma, K.F.; Hains, J.C.; Kroon, M.; Piters, A.J.M.; Kim, Y.J.

    2010-01-01

    In June 2009, 22 spectrometers from 14 institutes measured tropospheric and stratospheric NO2 from the ground for more than 11 days during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI), at Cabauw, NL (51.97° N, 4.93° E). All visible instruments used a common

  7. A stochastic view on column efficiency.

    Science.gov (United States)

    Gritti, Fabrice

    2018-03-09

    A stochastic model of transcolumn eddy dispersion along packed beds was derived. It was based on the calculation of the mean travel time of a single analyte molecule from one radial position to another. The exchange mechanism between two radial positions was governed by the transverse dispersion of the analyte across the column. The radial velocity distribution was obtained by flow simulations in a focused-ion-beam scanning electron microscopy (FIB-SEM) based 3D reconstruction from a 2.1 mm × 50 mm column packed with 2 μm BEH-C 18 particles. Accordingly, the packed bed was divided into three coaxial and uniform zones: (1) a 1.4 particle diameter wide, ordered, and loose packing at the column wall (velocity u w ), (2) an intermediate 130 μm wide, random, and dense packing (velocity u i ), and (3) the bulk packing in the center of the column (velocity u c ). First, the validity of this proposed stochastic model was tested by adjusting the predicted to the observed reduced van Deemter plots of a 2.1 mm × 50 mm column packed with 2 μm BEH-C 18 fully porous particles (FPPs). An excellent agreement was found for u i  = 0.93u c , a result fully consistent with the FIB-SEM observation (u i  = 0.95u c ). Next, the model was used to measure u i  = 0.94u c for 2.1 mm × 100 mm column packed with 1.6 μm Cortecs-C 18 superficially porous particles (SPPs). The relative velocity bias across columns packed with SPPs is then barely smaller than that observed in columns packed with FPPs (+6% versus + 7%). u w =1.8u i is measured for a 75 μm × 1 m capillary column packed with 2 μm BEH-C 18 particles. Despite this large wall-to-center velocity bias (+80%), the presence of the thin and ordered wall packing layer has no negative impact on the kinetic performance of capillary columns. Finally, the stochastic model of long-range eddy dispersion explains why analytical (2.1-4.6 mm i.d.) and capillary (columns can all be

  8. Computational analysis of ozonation in bubble columns

    International Nuclear Information System (INIS)

    Quinones-Bolanos, E.; Zhou, H.; Otten, L.

    2002-01-01

    This paper presents a new computational ozonation model based on the principle of computational fluid dynamics along with the kinetics of ozone decay and microbial inactivation to predict the performance of ozone disinfection in fine bubble columns. The model can be represented using a mixture two-phase flow model to simulate the hydrodynamics of the water flow and using two transport equations to track the concentration profiles of ozone and microorganisms along the height of the column, respectively. The applicability of this model was then demonstrated by comparing the simulated ozone concentrations with experimental measurements obtained from a pilot scale fine bubble column. One distinct advantage of this approach is that it does not require the prerequisite assumptions such as plug flow condition, perfect mixing, tanks-in-series, uniform radial or longitudinal dispersion in predicting the performance of disinfection contactors without carrying out expensive and tedious tracer studies. (author)

  9. Compact electron beam focusing column

    Science.gov (United States)

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-12-01

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  10. Mini-columns for Conducting Breakthrough Experiments. Design and Construction

    Energy Technology Data Exchange (ETDEWEB)

    Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ware, Stuart Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-11

    Experiments with moderately and strongly sorbing radionuclides (i.e., U, Cs, Am) have shown that sorption between experimental solutions and traditional column materials must be accounted for to accurately determine stationary phase or porous media sorption properties (i.e., sorption site density, sorption site reaction rate coefficients, and partition coefficients or Kd values). This report details the materials and construction of mini-columns for use in breakthrough columns to allow for accurate measurement and modeling of sorption parameters. Material selection, construction techniques, wet packing of columns, tubing connections, and lessons learned are addressed.

  11. Formaldehyde production from isoprene oxidation across NOx regimes

    Directory of Open Access Journals (Sweden)

    G. M. Wolfe

    2016-03-01

    Full Text Available The chemical link between isoprene and formaldehyde (HCHO is a strong, nonlinear function of NOx (i.e., NO + NO2. This relationship is a linchpin for top-down isoprene emission inventory verification from orbital HCHO column observations. It is also a benchmark for overall photochemical mechanism performance with regard to VOC oxidation. Using a comprehensive suite of airborne in situ observations over the southeast US, we quantify HCHO production across the urban–rural spectrum. Analysis of isoprene and its major first-generation oxidation products allows us to define both a "prompt" yield of HCHO (molecules of HCHO produced per molecule of freshly emitted isoprene and the background HCHO mixing ratio (from oxidation of longer-lived hydrocarbons. Over the range of observed NOx values (roughly 0.1–2 ppbv, the prompt yield increases by a factor of 3 (from 0.3 to 0.9 ppbv ppbv−1, while background HCHO increases by a factor of 2 (from 1.6 to 3.3 ppbv. We apply the same method to evaluate the performance of both a global chemical transport model (AM3 and a measurement-constrained 0-D steady-state box model. Both models reproduce the NOx dependence of the prompt HCHO yield, illustrating that models with updated isoprene oxidation mechanisms can adequately capture the link between HCHO and recent isoprene emissions. On the other hand, both models underestimate background HCHO mixing ratios, suggesting missing HCHO precursors, inadequate representation of later-generation isoprene degradation and/or underestimated hydroxyl radical concentrations. Detailed process rates from the box model simulation demonstrate a 3-fold increase in HCHO production across the range of observed NOx values, driven by a 100 % increase in OH and a 40 % increase in branching of organic peroxy radical reactions to produce HCHO.

  12. CH4, CO, and H2O spectroscopy for the Sentinel-5 Precursor mission: an assessment with the Total Carbon Column Observing Network measurements

    NARCIS (Netherlands)

    Galli, A.; Butz, A.; Scheepmaker, R.A.; Hasekamp, O.; Landgraf, J.; Tol, P.J.J.; Wunch, D.; Deutscher, N.M.; Toon, G.C.; Wennberg, P.O.; Griffith, D.W.T.; Aben, E.A.A.

    2012-01-01

    The TROPOspheric Monitoring Instrument (TROPOMI) will be part of ESA's Sentinel-5 Precursor (S5P) satellite platform scheduled for launch in 2015. TROPOMI will monitor methane and carbon monoxide concentrations in the Earth's atmosphere by measuring spectra of back-scattered sunlight in the

  13. CONTINUOUS FORMALDEHYDE MEASUREMENT SYSTEM BASED ON MODIFIED FOURIER TRANSFORM INFRARED SPECTROSCOPY

    Science.gov (United States)

    EPA is developing advanced open-path and cell-based optical techniques for time-resolved measurement of priority hazardous air pollutants such as formaldehyde (HCHO). Due to its high National Air Toxics Assessment risk factor, there is increasing interest in continuous measuremen...

  14. Airborne measurements of CO2 column concentrations made with a pulsed IPDA lidar using a multiple-wavelength-locked laser and HgCdTe APD detector

    Science.gov (United States)

    Abshire, James B.; Ramanathan, Anand K.; Riris, Haris; Allan, Graham R.; Sun, Xiaoli; Hasselbrack, William E.; Mao, Jianping; Wu, Stewart; Chen, Jeffrey; Numata, Kenji; Kawa, Stephan R.; Yang, Mei Ying Melissa; DiGangi, Joshua

    2018-04-01

    Here we report on measurements made with an improved CO2 Sounder lidar during the ASCENDS 2014 and 2016 airborne campaigns. The changes made to the 2011 version of the lidar included incorporating a rapidly wavelength-tunable, step-locked seed laser in the transmitter, using a much more sensitive HgCdTe APD detector and using an analog digitizer with faster readout time in the receiver. We also improved the lidar's calibration approach and the XCO2 retrieval algorithm. The 2014 and 2016 flights were made over several types of topographic surfaces from 3 to 12 km aircraft altitudes in the continental US. The results are compared to the XCO2 values computed from an airborne in situ sensor during spiral-down maneuvers. The 2014 results show significantly better performance and include measurement of horizontal gradients in XCO2 made over the Midwestern US that agree with chemistry transport models. The results from the 2016 airborne lidar retrievals show precisions of ˜ 0.7 parts per million (ppm) with 1 s averaging over desert surfaces, which is an improvement of about 8 times compared to similar measurements made in 2011. Measurements in 2016 were also made over fresh snow surfaces that have lower surface reflectance at the laser wavelengths. The results from both campaigns showed that the mean values of XCO2 retrieved from the lidar consistently agreed with those based on the in situ sensor to within 1 ppm. The improved precision and accuracy demonstrated in the 2014 and 2016 flights should benefit future airborne science campaigns and advance the technique's readiness for a space-based instrument.

  15. Development of a portable assembly-type cosmic-ray muon module for measuring the density structure of a column of magma

    International Nuclear Information System (INIS)

    Tanaka, Hiroyuki K.M.; Taira, Hideaki; Uchida, Tomohisa; Tanaka, Manobu; Shinohara, Hiroshi

    2010-01-01

    We have developed a portable assembly type cosmic-ray muon telescope system with power-effective real-time readings to monitor the internal structure of a volcano. Using this system, we have performed measurements at the Satsuma-Iojima volcano and studied the feasibility of using a continuous flux of cosmic-ray muons over the observation period. The system is based on the measurement of time-dependent muon absorption along different, nearly horizontal paths through a solid body. The rationale is that one can deduce the time-dependent changes in the density distribution of muon absorption in the interior of the object where an absorption variation, i.e., a density path variation, becomes an intensity variation since the muon energy spectrum is exponential or, expressed otherwise, it drops rapidly when the energy threshold increases. The muon telescope, which has a surface area of 1 m 2 , was installed at the observation point located 1.2 km from the summit crater of Satsuma-Iojima. Muon tracks within scintillator layers in the telescope were analyzed continuously by real-time three-dimensional image processing to measure the level of absorption along different ray paths through the summit crater region. A typical angular resolution of the muon detector of ±16 mrad corresponds to a spatial resolution of ±20 m at a distance of 1.2 km. Our results show the density structure determined in Satsuma-Iojima volcano, Japan, which is located above sea level. A density structure situated above sea level can be analyzed at a resolution that is significantly higher than is possible with conventional geophysical measurements. (author)

  16. Temperature Dependence of Factors Controlling Isoprene Emissions

    Science.gov (United States)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  17. The central column structure in SPHEX

    International Nuclear Information System (INIS)

    Duck, R.C.; French, P.A.; Browning, P.K.; Cunningham, G.; Gee, S.J.; al-Karkhy, A.; Martin, R.; Rusbridge, M.G.

    1994-01-01

    SPHEX is a gun injected spheromak in which a magnetised Marshall gun generates and maintains an approximately axisymmetric toroidal plasma within a topologically spherical flux conserving vessel. The central column has been defined as a region of high mean floating potential, f > up to ∼ 150 V, aligned with the geometric axis of the device. It has been suggested that this region corresponds to the open magnetic flux which is connected directly to the central electrode of the gun and links the toroidal annulus (in which f > ∼ 0 V). Poynting vector measurements have shown that the power required to drive toroidal current in the annulus is transmitted out of the column by the coherent 20 kHz mode which pervades the plasma. Measurements of the MHD dynamo in the column indicate an 'antidynamo' electric field due to correlated fluctuations in v and B at the 20 kHz mode frequency which is consistent with the time-averaged Ohm's Law. On shorting the gun electrodes, the density in the column region decays rapidly leaving a 'hole' of radius R c ∼ 7 cm. This agrees with the estimated dimension of the open flux from mean internal B measurements and axisymmetric force-free equilibrium modelling, but is considerably smaller than the radius of ∼ 13 cm inferred from the time-averaged potential. In standard operating conditions the gun delivers a current of I G ∼ 60 kA at V G ∼ 500 V for ∼ 1 ms, driving a toroidal current of I t ∼ 60 kA. Ultimately we wish to understand the mechanism which drives toroidal current in the annulus; the central column is of interest because of the crucial role it plays in this process. (author) 8 refs., 6 figs

  18. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  19. HI column density distribution function at z=0 : Connection to damped Ly alpha statistics

    NARCIS (Netherlands)

    Zwaan, Martin; Verheijen, MAW; Briggs, FH

    We present a measurement of the HI column density distribution function f(N-HI) at the present epoch for column densities > 10(20) cm(-2). These high column densities compare to those measured in damped Ly alpha lines seen in absorption against background quasars. Although observationally rare, it

  20. Experimental investigation of liquid chromatography columns by means of computed tomography

    DEFF Research Database (Denmark)

    Astrath, D.U.; Lottes, F.; Vu, Duc Thuong

    2007-01-01

    The efficiency of packed chromatographic columns was investigated experimentally by means of computed tomography (CT) techniques. The measurements were carried out by monitoring tracer fronts in situ inside the chromatographic columns. The experimental results were fitted using the equilibrium di...

  1. Column Aerosol Optical Properties and Aerosol Radiative Forcing During a Serious Haze-Fog Month over North China Plain in 2013 Based on Ground-Based Sunphotometer Measurements

    Science.gov (United States)

    Che, H.; Xia, X.; Zhu, J.; Li, Z.; Dubovik, O.; Holben, Brent N.; Goloub, P.; Chen, H.; Estelles, V.; Cuevas-Agullo, E.

    2014-01-01

    In January 2013, North China Plain experienced several serious haze events. Cimel sunphotometer measurements at seven sites over rural, suburban and urban regions of North China Plain from 1 to 30 January 2013 were used to further our understanding of spatial-temporal variation of aerosol optical parameters and aerosol radiative forcing (ARF). It was found that Aerosol Optical Depth at 500 nm (AOD500nm) during non-pollution periods at all stations was lower than 0.30 and increased significantly to greater than 1.00 as pollution events developed. The Angstrom exponent (Alpha) was larger than 0.80 for all stations most of the time. AOD500nm averages increased from north to south during both polluted and non-polluted periods on the three urban sites in Beijing. The fine mode AOD during pollution periods is about a factor of 2.5 times larger than that during the non-pollution period at urban sites but a factor of 5.0 at suburban and rural sites. The fine mode fraction of AOD675nm was higher than 80% for all sites during January 2013. The absorption AOD675nm at rural sites was only about 0.01 during pollution periods, while 0.03-0.07 and 0.01-0.03 during pollution and non-pollution periods at other sites, respectively. Single scattering albedo varied between 0.87 and 0.95 during January 2013 over North China Plain. The size distribution showed an obvious tri-peak pattern during the most serious period. The fine mode effective radius in the pollution period was about 0.01-0.08 microns larger than during nonpollution periods, while the coarse mode radius in pollution periods was about 0.06-0.38 microns less than that during nonpollution periods. The total, fine and coarse mode particle volumes varied by about 0.06-0.34 cu microns, 0.03-0.23 cu microns, and 0.03-0.10 cu microns, respectively, throughout January 2013. During the most intense period (1-16 January), ARF at the surface exceeded -50W/sq m, -180W/sq m, and -200W/sq m at rural, suburban, and urban sites

  2. Column-Oriented Database Systems (Tutorial)

    NARCIS (Netherlands)

    D. Abadi; P.A. Boncz (Peter); S. Harizopoulos

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as

  3. Water Column Sonar Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  4. Photolysis frequency measurement techniques: results of a comparison within the ACCENT project

    Directory of Open Access Journals (Sweden)

    K. C. Clemitshaw

    2008-09-01

    Full Text Available An intercomparison of different radiometric techniques measuring atmospheric photolysis frequencies j(NO2, j(HCHO and j(O1D was carried out in a two-week field campaign in June 2005 at Jülich, Germany. Three double-monochromator based spectroradiometers (DM-SR, three single-monochromator based spectroradiometers with diode-array detectors (SM-SR and seventeen filter radiometers (FR (ten j(NO2-FR, seven j(O1D-FR took part in this comparison. For j(NO2, all spectroradiometer results agreed within ±3%. For j(HCHO, agreement was slightly poorer between −8% and +4% of the DM-SR reference result. For the SM-SR deviations were explained by poorer spectral resolutions and lower accuracies caused by decreased sensitivities of the photodiode arrays in a wavelength range below 350 nm. For j(O1D, the results were more complex within +8% and −4% with increasing deviations towards larger solar zenith angles for the SM-SR. The direction and the magnitude of the deviations were dependent on the technique of background determination. All j(NO2-FR showed good linearity with single calibration factors being sufficient to convert from output voltages to j(NO2. Measurements were feasible until sunset and comparison with previous calibrations showed good long-term stability. For the j(O1D-FR, conversion from output voltages to j(O1D needed calibration factors and correction functions considering the influences of total ozone column and elevation of the sun. All instruments showed good linearity at photolysis frequencies exceeding about 10% of maximum values. At larger solar zenith angles, the agreement was non-uniform with deviations explainable by insufficient correction functions. Comparison with previous calibrations for some j(O1D-FR indicated

  5. Detection of carbon monoxide pollution from cities and wildfires on regional and urban scales: the benefit of CO column retrievals from SCIAMACHY 2.3 µm measurements under cloudy conditions

    Directory of Open Access Journals (Sweden)

    T. Borsdorff

    2018-05-01

    Full Text Available In the perspective of the upcoming TROPOMI Sentinel-5 Precursor carbon monoxide data product, we discuss the benefit of using CO total column retrievals from cloud-contaminated SCIAMACHY 2.3 µm shortwave infrared spectra to detect atmospheric CO enhancements on regional and urban scales due to emissions from cities and wildfires. The study uses the operational Sentinel-5 Precursor algorithm SICOR, which infers the vertically integrated CO column together with effective cloud parameters. We investigate its capability to detect localized CO enhancements distinguishing between clear-sky observations and observations with low (<  1.5 km and medium–high clouds (1.5–5 km. As an example, we analyse CO enhancements over the cities Paris, Los Angeles and Tehran as well as the wildfire events in Mexico–Guatemala 2005 and Alaska–Canada 2004. The CO average of the SCIAMACHY full-mission data set of clear-sky observations can detect weak CO enhancements of less than 10 ppb due to air pollution in these cities. For low-cloud conditions, the CO data product performs similarly well. For medium–high clouds, the observations show a reduced CO signal both over Tehran and Los Angeles, while for Paris no significant CO enhancement can be detected. This indicates that information about the vertical distribution of CO can be obtained from the SCIAMACHY measurements. Moreover, for the Mexico–Guatemala fires, the low-cloud CO data captures a strong outflow of CO over the Gulf of Mexico and the Pacific Ocean and so provides complementary information to clear-sky retrievals, which can only be obtained over land. For both burning events, enhanced CO values are even detectable with medium–high-cloud retrievals, confirming a distinct vertical extension of the pollution. The larger number of additional measurements, and hence the better spatial coverage, significantly improve the detection of wildfire pollution using both the clear-sky and cloudy

  6. Detection of carbon monoxide pollution from cities and wildfires on regional and urban scales: the benefit of CO column retrievals from SCIAMACHY 2.3 µm measurements under cloudy conditions

    Science.gov (United States)

    Borsdorff, Tobias; Andrasec, Josip; aan de Brugh, Joost; Hu, Haili; Aben, Ilse; Landgraf, Jochen

    2018-05-01

    In the perspective of the upcoming TROPOMI Sentinel-5 Precursor carbon monoxide data product, we discuss the benefit of using CO total column retrievals from cloud-contaminated SCIAMACHY 2.3 µm shortwave infrared spectra to detect atmospheric CO enhancements on regional and urban scales due to emissions from cities and wildfires. The study uses the operational Sentinel-5 Precursor algorithm SICOR, which infers the vertically integrated CO column together with effective cloud parameters. We investigate its capability to detect localized CO enhancements distinguishing between clear-sky observations and observations with low (Paris, Los Angeles and Tehran as well as the wildfire events in Mexico-Guatemala 2005 and Alaska-Canada 2004. The CO average of the SCIAMACHY full-mission data set of clear-sky observations can detect weak CO enhancements of less than 10 ppb due to air pollution in these cities. For low-cloud conditions, the CO data product performs similarly well. For medium-high clouds, the observations show a reduced CO signal both over Tehran and Los Angeles, while for Paris no significant CO enhancement can be detected. This indicates that information about the vertical distribution of CO can be obtained from the SCIAMACHY measurements. Moreover, for the Mexico-Guatemala fires, the low-cloud CO data captures a strong outflow of CO over the Gulf of Mexico and the Pacific Ocean and so provides complementary information to clear-sky retrievals, which can only be obtained over land. For both burning events, enhanced CO values are even detectable with medium-high-cloud retrievals, confirming a distinct vertical extension of the pollution. The larger number of additional measurements, and hence the better spatial coverage, significantly improve the detection of wildfire pollution using both the clear-sky and cloudy CO retrievals. Due to the improved instrument performance of the TROPOMI instrument with respect to its precursor SCIAMACHY, the upcoming Sentinel-5

  7. LIQUID-LIQUID EXTRACTION COLUMNS

    Science.gov (United States)

    Thornton, J.D.

    1957-12-31

    This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

  8. Column-Oriented Database Systems (Tutorial)

    OpenAIRE

    Abadi, D.; Boncz, Peter; Harizopoulos, S.

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subset of a table’s columns becomes faster, at the potential expense of excessive disk-head s...

  9. Investigation of Gas Holdup in a Vibrating Bubble Column

    Science.gov (United States)

    Mohagheghian, Shahrouz; Elbing, Brian

    2015-11-01

    Synthetic fuels are part of the solution to the world's energy crisis and climate change. Liquefaction of coal during the Fischer-Tropsch process in a bubble column reactor (BCR) is a key step in production of synthetic fuel. It is known from the 1960's that vibration improves mass transfer in bubble column. The current study experimentally investigates the effect that vibration frequency and amplitude has on gas holdup and bubble size distribution within a bubble column. Air (disperse phase) was injected into water (continuous phase) through a needle shape injector near the bottom of the column, which was open to atmospheric pressure. The air volumetric flow rate was measured with a variable area flow meter. Vibrations were generated with a custom-made shaker table, which oscillated the entire column with independently specified amplitude and frequency (0-30 Hz). Geometric dependencies can be investigated with four cast acrylic columns with aspect ratios ranging from 4.36 to 24, and injector needle internal diameters between 0.32 and 1.59 mm. The gas holdup within the column was measured with a flow visualization system, and a PIV system was used to measure phase velocities. Preliminary results for the non-vibrating and vibrating cases will be presented.

  10. Coastal circulation and water-column properties in the War in the Pacific National Historical Park, Guam: measurements and modeling of waves, currents, temperature, salinity, and turbidity, April-August 2012

    Science.gov (United States)

    Storlazzi, Curt D.; Cheriton, Olivia M.; Lescinski, Jamie M.R.; Logan, Joshua B.

    2014-01-01

    The U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center (PCMSC) initiated an investigation in the National Park Service’s (NPS) War in the Pacific National Historical Park (WAPA) to provide baseline scientific information on coastal circulation and water-column properties along west-central Guam, focusing on WAPA’s Agat Unit, as it relates to the transport and settlement of coral larvae, fish, and other marine organisms. The oceanographic data and numerical circulation modeling results from this study demonstrate that circulation in Agat Bay was strongly driven by winds and waves at longer (>1 day) timescales and by the tides at shorter (Turbidity was relatively low in Agat Bay and was similar to levels measured elsewhere along west-central Guam. The numerical circulation modeling results provide insight into the potential paths of buoyant material released from a series of locations along west-central Guam under summer non-trade wind forcing conditions that characterize coral spawning events. This information may be useful in evaluating the potential zones of influence/impact resulting from transport by surface currents of material released from these select locations.

  11. Detection of carbon monoxide pollution from cities and wildfires on regional and urban scales: the benefit of CO column retrievals from SCIAMACHY 2.3 µm measurements under cloudy conditions

    OpenAIRE

    Borsdorff, Tobias; Andrasec, Josip; aan de Brugh, Joost; Hu, Haili; Aben, Ilse; Landgraf, Jochen

    2018-01-01

    In the perspective of the upcoming TROPOMI Sentinel-5 Precursor carbon monoxide data product, we discuss the benefit of using CO total column retrievals from cloud-contaminated SCIAMACHY 2.3 µm shortwave infrared spectra to detect atmospheric CO enhancements on regional and urban scales due to emissions from cities and wildfires. The study uses the operational Sentinel-5 Precursor algorithm SICOR, which infers the vertically integrated CO column together with effective cl...

  12. Radiotracer Imaging of Sediment Columns

    Science.gov (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  13. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.

    2017-12-01

    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  14. Transformation of 3-chloroallyl alcohol in water-saturated subsoil studied with a column method

    NARCIS (Netherlands)

    Beltman, W.H.J.; Leistra, M.; Matser, A.M.

    1996-01-01

    The performance of a newly developed column method for pesticide transformation rate measurements in the subsoil was tested using (Z)- and (E)-3-chloroallyl alcohol as model compounds. The subsoil columns were filled in situ. In the column experiment the half-life ranged from 0.5-5.2 d for

  15. Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns?

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Dennis, Gary R; Shalliker, R Andrew

    2015-08-19

    Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. Copyright © 2015. Published by Elsevier B.V.

  16. Numerical Simulation of Fluid Dynamics in a Monolithic Column

    Directory of Open Access Journals (Sweden)

    Kazuhiro Yamamoto

    2017-01-01

    Full Text Available As for the measurement of polycyclic aromatic hydrocarbons (PAHs, ultra-performance liquid chromatography (UPLC is used for PAH identification and densitometry. However, when a solvent containing a substance to be identified passes through a column of UPLC, a dedicated high-pressure-proof device is required. Recently, a liquid chromatography instrument using a monolithic column technology has been proposed to reduce the pressure of UPLC. The present study tested five types of monolithic columns produced in experiments. To simulate the flow field, the lattice Boltzmann method (LBM was used. The velocity profile was discussed to decrease the pressure drop in the ultra-performance liquid chromatography (UPLC system.

  17. Characterization of Bubble Size Distributions within a Bubble Column

    OpenAIRE

    Shahrouz Mohagheghian; Brian R. Elbing

    2018-01-01

    The current study experimentally examines bubble size distribution (BSD) within a bubble column and the associated characteristic length scales. Air was injected into a column of water via a single injection tube. The column diameter (63–102 mm), injection tube diameter (0.8–1.6 mm) and superficial gas velocity (1.4–55 mm/s) were varied. Large samples (up to 54,000 bubbles) of bubble sizes measured via 2D imaging were used to produce probability density functions (PDFs). The PDFs were used to...

  18. EPA True NO2 ground site measurements – multiple sites, TCEQ ground site measurements of meteorological and air pollution parameters – multiple sites ,GeoTASO NO2 Vertical Column

    Data.gov (United States)

    U.S. Environmental Protection Agency — EPA True NO2 ground site measurements – multiple sites - http://www-air.larc.nasa.gov/cgi-bin/ArcView/discover-aq.tx-2013; TCEQ ground site measurements of...

  19. Denitrification in the water column of the central Baltic Sea

    DEFF Research Database (Denmark)

    Dalsgaard, Tage; De Brabandere, Loreto; Hall, Per O. J.

    2013-01-01

    Removal of fixed nitrogen in the water column of the eastern Gotland Basin, central Baltic Sea, was studied during two cruises in September 2008 and August 2010. The water column was stratified with anoxic sulfidic bottom water meeting oxic nitrate containing water at the oxic–anoxic interface......3 or sulfide concentrations were converted to in situ rates using the measured water column concentrations of NO3 and sulfide and the actual measured relations between NO3 and sulfide concentrations and enitrification rates. In situ denitrification ranged from 0.24 to 15.9 nM N2 h1. Assuming...... area. Even with an active denitrification layer of 3–6 m thickness the pelagic denitrification per unit area clearly exceeded sediment denitrification rates elsewhere in the Baltic Sea. When extrapolated to the entire Baltic Proper (BP) denitrification in the water column was in the range of 132...

  20. Design concept of control system for cryogenic distillation columns of fusion reactor

    International Nuclear Information System (INIS)

    Yamanishi, Toshihiko; Okuno, Kenji

    1993-09-01

    Control systems were designed for cryogenic distillation columns in the main fuel cycle and the breeder blanket interface systems of fusion reactors. Three basic control modes were proposed for the column whose top product was more important; the column whose bottom product is more important; and the column having a feed back stream. The key component in the important product stream was selected for each column, and the analysis method for measurement of this key component was discussed. Some of the columns need the gas chromatography as the analysis instrument of the control system. The time required for the measurement of product purity by the gas chromatography considerably affects the stability of the control system. A significant conclusion is that permissible time is about 20 min. It is possible to complete the measurement within 20 minute by the gas chromatography. The gas chromatography is applicable for the control system of the column. (author)

  1. Cervical column morphology and craniofacial profiles in monozygotic twins.

    Science.gov (United States)

    Sonnesen, Liselotte; Pallisgaard, Carsten; Kjaer, Inger

    2008-02-01

    Previous studies have described the relationships between cervical column morphology and craniofacial morphology. The aims of the present study were to describe cervical column morphology in 38 pairs of adult monozygotic (MZ) twins, and compare craniofacial morphology in twins with fusions with craniofacial morphology in twins without fusion. Visual assessment of cervical column morphology and cephalometric measurements of craniofacial morphology were performed on profile radiographs. In the cervical column, fusion between corpora of the second and third vertebrae was registered as fusion. In the twin group, 8 twin pairs had fusion of the cervical column in both individuals within the pair (sub-group A), 25 pairs had no fusions (subgroup B), and in 5 pairs, cervical column morphology was different within the pair (subgroup C), as one twin had fusion and the other did not. Comparison of craniofacial profiles showed a tendency to increased jaw retrognathia, larger cranial base angle, and larger mandibular inclination in subgroup A than in subgroup B. The same tendency was observed within subgroup C between the individual twins with fusion compared with those without fusion. These results confirm that cervical fusions and craniofacial morphology may be interrelated in twins when analysed on profile radiographs. The study also documents that differences in cervical column morphology can occur in individuals within a pair of MZ twins. It illustrates that differences in craniofacial morphology between individuals within a pair of MZ twins can be associated with cervical fusion.

  2. Chromatographic properties PLOT multicapillary columns.

    Science.gov (United States)

    Nikolaeva, O A; Patrushev, Y V; Sidelnikov, V N

    2017-03-10

    Multicapillary columns (MCCs) for gas chromatography make it possible to perform high-speed analysis of the mixtures of gaseous and volatile substances at a relatively large amount of the loaded sample. The study was performed using PLOT MCCs for gas-solid chromatography (GSC) with different stationary phases (SP) based on alumina, silica and poly-(1-trimethylsilyl-1-propyne) (PTMSP) polymer as well as porous polymers divinylbenzene-styrene (DVB-St), divinylbenzene-vinylimidazole (DVB-VIm) and divinylbenzene-ethylene glycol dimethacrylate (DVB-EGD). These MCCs have the efficiency of 4000-10000 theoretical plates per meter (TP/m) and at a column length of 25-30cm can separate within 10-20s multicomponent mixtures of substances belonging to different classes of chemical compounds. The sample amount not overloading the column is 0.03-1μg and depends on the features of a porous layer. Examples of separations on some of the studied columns are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Assessment of the potential implementation of the Fricke dosimetric system to measure the gamma dose rate in a mixed field at the Central Irradiation Facility of the Thermal Column at RA-3

    International Nuclear Information System (INIS)

    Curotto, P.; Pozzi, E.C.C.; Thorp, S.I.; Casal, M.

    2013-01-01

    Introduction: The characterization of the mixed field, i.e. neutron and gamma radiation, at the Central Irradiation Facility of the Thermal Column (FCCT) at RA-3 is pivotal to the radiobiology experiments carried out there. One of the greatest difficulties of gamma dosimetry in a mixed field such as the FCCT field is to discriminate the perturbation induced by the high neutron flux. Given that the neutron spectrum of the source is very well characterized, it is of interest to have an alternative way of measuring gamma dose rate to be able to compare the results with those currently derived from an ionization chamber (IC). The Fricke dosimetric system is widely used as an absolute dosimeter in pure, very high dose radiation fields. The experimental set-up of these dosimeters exhibits advantages compared to instrumentation with IC. The aim of the present study was to adapt the system to use it as a measuring method at FCCT and perform a comparative analysis. Materials and Methods: Once the technique to prepare the dosimeters was adapted at our laboratory the following irradiations were carried out: one in a pure, known, gamma field, and four in the mixed FCCT field in the same position, employing 3 different configurations to obtain different relations between the radiation components in the field. The following configurations were employed: a) with closed neutron shielding, b) with open neutron shielding and c) no shielding. The results were compared with those derived from measurements with the IC. Results: In pure gamma field experience the following results were obtained: the dose measured by the IC was (44.6 ± 0.5) Gy (in air) and Fricke dose was (48.2 ± 1.1) Gy. Comparing the configurations with closed and open neutron shielding, the IC signal rose by 4% (considered not significant) whereas the Fricke dose rate increased by 15%. Comparing the configurations with closed shielding and no shielding, the gamma dose rate measured with the Fricke system rose by 153

  4. Buckling driven debonding in sandwich columns

    DEFF Research Database (Denmark)

    Østergaard, Rasmus Christian

    2008-01-01

    results from two mechanisms: (a) interaction of local debond buckling and global buckling and (b) the development of a damaged zone at the debond crack tip. Based on the pronounced imperfection sensitivity, the author predicts that an experimental measurement of the strength of sandwich structures may......A compression loaded sandwich column that contains a debond is analyzed using a geometrically non-linear finite element model. The model includes a cohesive zone along one face sheet/core interface whereby the debond can extend by interface crack growth. Two geometrical imperfections are introduced...

  5. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya

    2016-01-01

    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  6. SPEEDUPtrademark ion exchange column model

    International Nuclear Information System (INIS)

    Hang, T.

    2000-01-01

    A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUptrademark software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLigtrademark ion exchange resins, once the experimental data are complete

  7. Protocols for the measurement of the F2-isoprostane, 15(S)-8-iso-prostaglandin F2α, in biological samples by GC-MS or GC-MS/MS coupled with immunoaffinity column chromatography.

    Science.gov (United States)

    Tsikas, Dimitrios; Suchy, Maria-Theresia

    2016-04-15

    Arachidonic acid, the origin of the eicosanoids family, occurs in biological samples as free acid and as ester in lipids. Free arachidonic acid is oxidized to numerous metabolites by means of enzymes including cyclooxygenase (COX). Arachidonic acid esterified to lipids is attacked by reactive oxygen species (ROS) to generate numerous oxidized arachidonic acid derivatives. Generally, it is assumed that ROS-derived arachidonic acid derivatives are distinct from those generated by enzymes such as COX. Therefore, ROS-generated eicosanoids are considered specific biomarkers of oxidative stress. However, there are serious doubts concerning a strict distinction between the enzyme-derived eicosanoids and the ROS-derived iso-eicosanoids. Prominent examples are prostaglandin F2α (PGF2α) and 15(S)-8-iso-prostaglandin F2α (15(S)-8-iso-PGF2α) which have been originally considered to exclusively derive from COX and ROS, respectively. There is convincing evidence that both COX and ROS can oxidize arachidonic acid to PGF2α and 15(S)-8-iso-PGF2α. Thus, many results previously reported for 15(S)-8-iso-PGF2α as exclusive ROS-dependent reaction product, and consequently as a specific biomarker of oxidative stress, require a careful re-examination which should also consider the analytical methods used to measure 15(S)-8-iso-PGF2α. This prominent but certainly not the only example underlines more than ever the importance of the analytical chemistry in basic and clinical research areas of oxidative stress. In the present work, we report analytical protocols for the reliable quantitative determination of 15(S)-8-iso-PGF2α in human biological samples including plasma and urine by mass spectrometry coupled to gas chromatography (GC-MS, GC-MS/MS) after specific isolation of endogenous 15(S)-8-iso-PGF2α and the externally added internal standard [3,3',4,4'-(2)H4]-15(S)-8-iso-PGF2α by immunoaffinity column chromatography (IAC). 15(S)-8-iso-PGF2α esterified to plasma lipids is

  8. Two generalizations of column-convex polygons

    International Nuclear Information System (INIS)

    Feretic, Svjetlan; Guttmann, Anthony J

    2009-01-01

    Column-convex polygons were first counted by area several decades ago, and the result was found to be a simple, rational, generating function. In this work we generalize that result. Let a p-column polyomino be a polyomino whose columns can have 1, 2, ..., p connected components. Then column-convex polygons are equivalent to 1-convex polyominoes. The area generating function of even the simplest generalization, namely 2-column polyominoes, is unlikely to be solvable. We therefore define two classes of polyominoes which interpolate between column-convex polygons and 2-column polyominoes. We derive the area generating functions of those two classes, using extensions of existing algorithms. The growth constants of both classes are greater than the growth constant of column-convex polyominoes. Rather tight lower bounds on the growth constants complement a comprehensive asymptotic analysis.

  9. Experimental validation of pulsed column inventory estimators

    International Nuclear Information System (INIS)

    Beyerlein, A.L.; Geldard, J.F.; Weh, R.; Eiben, K.; Dander, T.; Hakkila, E.A.

    1991-01-01

    Near-real-time accounting (NRTA) for reprocessing plants relies on the timely measurement of all transfers through the process area and all inventory in the process. It is difficult to measure the inventory of the solvent contractors; therefore, estimation techniques are considered. We have used experimental data obtained at the TEKO facility in Karlsruhe and have applied computer codes developed at Clemson University to analyze this data. For uranium extraction, the computer predictions agree to within 15% of the measured inventories. We believe this study is significant in demonstrating that using theoretical models with a minimum amount of process data may be an acceptable approach to column inventory estimation for NRTA. 15 refs., 7 figs

  10. Calculation code PULCO for Purex process in pulsed column

    International Nuclear Information System (INIS)

    Gonda, Kozo; Matsuda, Teruo

    1982-03-01

    The calculation code PULCO, which can simulate the Purex process using a pulsed column as an extractor, has been developed. The PULCO is based on the fundamental concept of mass transfer that the mass transfer within a pulsed column occurs through the interface of liquid drops and continuous phase fluid, and is the calculation code different from conventional ones, by which various phenomena such as the generation of liquid drops, their rising and falling, and the unification of liquid drops actually occurring in a pulsed column are exactly reflected and can be correctly simulated. In the PULCO, the actually measured values of the fundamental quantities representing the extraction behavior of liquid drops in a pulsed column are incorporated, such as the mass transfer coefficient of each component, the diameter and velocity of liquid drops in a pulsed column, the holdup of dispersed phase, and axial turbulent flow diffusion coefficient. The verification of the results calculated with the PULCO was carried out by installing a pulsed column of 50 mm inside diameter and 2 m length with 40 plate stage in a glove box for unirradiated uranium-plutonium mixed system. The results of the calculation and test were in good agreement, and the validity of the PULCO was confirmed. (Kako, I.)

  11. Insights into Tikhonov regularization: application to trace gas column retrieval and the efficient calculation of total column averaging kernels

    Directory of Open Access Journals (Sweden)

    T. Borsdorff

    2014-02-01

    Full Text Available Insights are given into Tikhonov regularization and its application to the retrieval of vertical column densities of atmospheric trace gases from remote sensing measurements. The study builds upon the equivalence of the least-squares profile-scaling approach and Tikhonov regularization method of the first kind with an infinite regularization strength. Here, the vertical profile is expressed relative to a reference profile. On the basis of this, we propose a new algorithm as an extension of the least-squares profile scaling which permits the calculation of total column averaging kernels on arbitrary vertical grids using an analytic expression. Moreover, we discuss the effective null space of the retrieval, which comprises those parts of a vertical trace gas distribution which cannot be inferred from the measurements. Numerically the algorithm can be implemented in a robust and efficient manner. In particular for operational data processing with challenging demands on processing time, the proposed inversion method in combination with highly efficient forward models is an asset. For demonstration purposes, we apply the algorithm to CO column retrieval from simulated measurements in the 2.3 μm spectral region and to O3 column retrieval from the UV. These represent ideal measurements of a series of spaceborne spectrometers such as SCIAMACHY, TROPOMI, GOME, and GOME-2. For both spectral ranges, we consider clear-sky and cloudy scenes where clouds are modelled as an elevated Lambertian surface. Here, the smoothing error for the clear-sky and cloudy atmosphere is significant and reaches several percent, depending on the reference profile which is used for scaling. This underlines the importance of the column averaging kernel for a proper interpretation of retrieved column densities. Furthermore, we show that the smoothing due to regularization can be underestimated by calculating the column averaging kernel on a too coarse vertical grid. For both

  12. 29 CFR 1926.755 - Column anchorage.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Column anchorage. 1926.755 Section 1926.755 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Steel Erection § 1926.755 Column anchorage. (a) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4 anchor...

  13. Adsorption columns for use in radioimmunoassays

    International Nuclear Information System (INIS)

    1976-01-01

    Adsorption columns are provided which can be utilized in radioimmunoassay systems such as those involving the separation of antibody-antigen complexes from free antigens. The preparation of the columns includes the treatment of retaining substrate material to render it hydrophilic, preparation and degassing of the separation material and loading the column

  14. Thermal process of an air column

    International Nuclear Information System (INIS)

    Lee, F.T.

    1994-01-01

    Thermal process of a hot air column is discussed based on laws of thermodynamics. The kinetic motion of the air mass in the column can be used as a power generator. Alternatively, the column can also function as a exhaust/cooler

  15. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns.

    Science.gov (United States)

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Column selectivity in reversed-phase liquid chromatography I. A general quantitative relationship.

    Science.gov (United States)

    Wilson, N S; Nelson, M D; Dolan, J W; Snyder, L R; Wolcott, R G; Carr, P W

    2002-07-05

    Retention factors k have been measured for 67 neutral, acidic and basic solutes of highly diverse molecular structure (size, shape, polarity, hydrogen bonding, pKa, etc.) on 10 different C18 columns (other conditions constant). These data have been combined with k values from a previous study (86 solutes, five different C8 and C18 columns) to develop a six-term equation for the correlation of retention as a function of solute and column. Values of k can be correlated with an accuracy of +/- 1-2% (1 standard deviation). This suggests that all significant contributions to column selectivity have been identified (and can be measured) for individual alkyl-silica columns which do not have an embedded polar group. That is, columns of the latter kind can be quantitatively characterized in terms of selectivity for use in the separation of any sample.

  17. Proposed Trace Gas Measurements Over the Western United States for TROPOMI Validation

    Science.gov (United States)

    Parworth, Caroline L.; Marrero, Josette E.; Yates, Emma L.; Ryoo, Ju-Mee; Iraci, Laura T.

    2018-01-01

    The Alpha Jet Atmospheric eXperiment (AJAX), located in the Bay Area of California, is a joint effort between NASA Ames Research Center and H211, LCC. AJAX makes in-situ airborne measurements of trace gases 2-4 times per month, resulting in over 216 flights since 2011. Current measurements include ozone (O3), carbon dioxide (CO2), methane (CH4), water (H2O), formaldehyde (HCHO), and meteorological measurements (i.e., ambient pressure, temperature, and 3D winds). Currently, the AJAX team is working to incorporate nitrogen dioxide (NO2) measurements with a Cavity Attenuated Phase Shift Spectrometer (CAPS). Successful science flights coincident with satellite overpasses have been performed since 2011 by the Alpha Jet, with more than 40 flights under the Greenhouse Observing SATellite (GOSAT) and several flights under the Orbiting Carbon Observatory-2 (OCO-2). Results from these flights, which have covered a range of different surfaces and seasonal conditions, will be presented. In-situ vertical profiles of O3, CO2, CH4, H2O, HCHO, and NO2 from the surface to 28,000 feet made by AJAX will also be valuable for satellite validation of data products obtained from the TROPOspheric Montoring Instrument (TROPOMI). TROPOMI is on board the Copernicus Sentinel-5 precursor (S5p) satellite, with level 2 products including O3, CO, CH4, HCHO, NO2, and aerosols.

  18. Evaluation of Packed Distillation Columns I - Atmospheric Pressure

    National Research Council Canada - National Science Library

    Reynolds, Thaine

    1951-01-01

    .... Four column-packing combinations of the glass columns and four column-packing combinations of the steel columns were investigated at atmospheric pressure using a test mixture of methylcyclohexane...

  19. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  20. First comparison of formaldehyde integral contents in ABL retrieved during clear-sky and overcast conditions by ZDOAS technique

    Science.gov (United States)

    Ivanov, Victor; Borovski, Alexander; Postylyakov, Oleg

    2017-10-01

    Formaldehyde (HCHO) is involved in a lot of chemical reactions in the atmosphere. Taking into account that HCHO basically undergo by photolysis and reaction with hydroxyl radical within a few hours, short-lived VOCs and direct HCHO emissions can cause local HCHO enhancement over certain areas, and, hence, exceeding background level of HCHO can be examined as a local pollution of the atmosphere by VOCs or existence of a local HCHO source. Several retrieval algorithms applicable for DOAS measurements in cloudless were previously developed. In previous works we proposed a new algorithm applicable for the overcast conditions. The algorithm has the typical F-coefficient error of about 10% for winter season, about 5% for summer season, and varying from 15 to 45% for transition season if the atmospheric boundary layer is below the cloud base. In this paper we briefly present our results of the HCHO vertical column retrieval measured at Zvenigorod Scientific Station (ZSS) for overcast. ZSS (55°41'49''N, 36°46'29''E) is located in Moscow region in 38 km west from Moscow. Because Western winds prevail in this region, ZSS is a background station the most part of time. But in cases of Eastern wind, the air quality at ZSS is affected by Moscow megapolis, and polluted air masses formed above Moscow can reach station in a few hours. Due to the absence of alternative overcast data of HCHO, we compare our overcast data with the HCHO vertical content, which we obtained for clear sky. We investigate similarities and differences in their statistical behavior in different air mass. The average overcast HCHO data have similar to clear-sky HCHO positive temperature trends for all wind direction. We found that the average retrieved overcast HCHO contents are systematically greater than the clear-sky retrieval data. But the difference between data retrieved for the overcast and clear-sky conditions are different for Eastern and Western winds. This difference is about 0.5×1016 mol cm-2

  1. Retention of nitrous gases in scrubber columns

    International Nuclear Information System (INIS)

    Nakazone, A.K.; Costa, R.C.; Lobao, A.S.T.; Matsuda, H.T.; Araujo, B.F. de

    1988-01-01

    During the UO 2 dissolution in nitric acid, some different species of NO (sub)x are released. The off gas can either be refluxed to the dissolver or be released and retained on special colums. The final composition of the solution is the main parameter to take in account. A process for nitrous gases retention using scrubber colums containing H 2 O or diluted HNO 3 is presented. Chemiluminescence measurement was employed to NO x evaluation before and after scrubing. Gas flow, temperature, residence time are the main parameters considered in this paper. For the dissolution of 100g UO 2 in 8M nitric acid, a 6NL/h O 2 flow was the best condition for the NO/NO 2 oxidation with maximum absorption in the scrubber columns. (author) [pt

  2. Development of pulsed plate columns for fast reactor fuel reprocessing

    International Nuclear Information System (INIS)

    Jenkins, J.A.; Logsdail, D.H.; Lyall, E.; Myers, P.E.; Partridge, B.A.

    1987-01-01

    The UK Atomic Energy Authority has undertaken a development programme on solvent extraction equipment for reprocessing fast reactor fuels. As part of this programme a solvent extraction pilot plant has been built at Harwell in which a variety of flowsheet conditions can be simulated using the system uranyl nitrate/nitric acid (UN/HNO 3 ) - 20% tri-n-butyl phosphate in odourless kerosene (TBP/OK). The main purpose of present pilot plant operations is to study the performance of pulsed plate columns, with the following specific objectives: to measure the volumetric throughput capacity of the columns, - to study the effect of scale-up of column diameter on U mass transfer performance, - to provide hydraulic and mass transfer data for a dynamic simulation model of pulsed column operation, - to develop and test instruments and ancillary equipment. This poster describes the pilot plant and is illustrated by experimental data, with particular reference to an external settler for controlling the removal of aqueous phase from columns operated with the aqueous phase dispersed

  3. Particle densities in a positive column He-I+ discharge

    International Nuclear Information System (INIS)

    Gato, T.

    1980-01-01

    In a positive column He-1 + laser discharge, the He + ion density has been determined directly from the absorption of the HeII 30.3 nm resonance line measured by a modified absorption method, and the electron density has been obtained using this measured He + ion density. The population densities of the upper and lower states of the 612.7 nm laser line have also been measured roughly. (orig.)

  4. Formaldehyde and Glyoxal Measurements as Tracers of Oxidation Chemistry in the Amazon Basin

    Science.gov (United States)

    Thayer, M. P.; Dorris, M. R.; Keutsch, F. N.; Springston, S. R.; Jimenez, J. L.; Palm, B. B.; Seco, R.; Kim, S.; Yee, L.; Wernis, R. A.; Goldstein, A. H.; Isaacman-VanWertz, G. A.; Liu, Y.; Martin, S. T.

    2015-12-01

    Formaldehyde (HCHO) and glyoxal (CHOCHO) are important tracers for oxidative processes in the atmosphere such as oxidation of volatile organic compounds (VOCs) and production of HO2 radicals by photolysis or reaction with OH. Products of VOC oxidation and radical cycling, such as aerosols and tropospheric ozone, have direct impacts on human health. During the Green Ocean Amazon campaign (GoAmazon2014/5), HCHO and CHOCHO measurements were obtained together with OH, RO2+HO2, CO, CO2, O3, NOx, (o)VOCs, and aerosol particle size distribution. HCHO concentration was measured by the Madison FIber Laser-Induced Fluorescence (FILIF) instrument, while CHOCHO concentrations were collected by the Madison Laser-Induced Phosphorescence (Mad-LIP) instrument. Here we present data collected during 2014 at the T3 field site, 60 km to the west of Manaus, Brazil (3°12'47.82"S, 60°35'55.32"W). The T3 GoAmazon site varies between sampling strictly pristine (biogenic) emissions and influence from anthropogenic emissions from Manaus, depending on meteorological conditions. Here we present overall trends and regimes observed during the campaign, with a focus on HCHO, CHOCHO, and related species within the context of VOC oxidation and secondary pollutant production. We acknowledge the support from the Central Office of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA), the Instituto Nacional de Pesquisas da Amazonia (INPA), and the Universidade do Estado do Amazonia (UEA). The work was conducted under 001030/2012-4 of the Brazilian National Council for Scientific and Technological Development (CNPq). Data were collected from the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a U.S. Department of Energy Office of Science user facility sponsored by the Office of Biological and Environmental Research. Additionally, we acknowledge logistical support from the ARM Climate Research Facility. Additional funding from: NSF GRFP DGE-1256259, and NSF AGS-1051338

  5. Picobubble enhanced column flotation of fine coal

    Energy Technology Data Exchange (ETDEWEB)

    Tao, D.; Yu, S.; Parekh, B.K. [University of Kentucky, Lexington, KY (United States). Mining Engineering

    2006-07-01

    The purpose is to study the effectiveness of picobubbles in the column flotation of -28 mesh fine coal particles. A flotation column with a picobubble generator was developed and tested for enhancing the recovery of ultrafine coal particles. The picobubble generator was designed using the hydrodynamic cavitation principle. A metallurgical and a steam coal were tested in the apparatus. The results show that the use of picobubbles in a 2in. flotation column increased the recovery of fine coal by 10 to 30%. The recovery rate varied with feed rate, collector dosage, and other column conditions. 40 refs., 8 figs., 2 tabs.

  6. Thermally stable dexsil-400 glass capillary columns

    International Nuclear Information System (INIS)

    Maskarinec, M.P.; Olerich, G.

    1980-01-01

    The factors affecting efficiency, thermal stability, and reproducibility of Dexsil-400 glass capillary columns for gas chromatography in general, and for polycyclic aromatic hydrocarbons (PAHs) in particular were investigated. Columns were drawn from Kimble KG-6 (soda-lime) glass or Kimox (borosilicate) glass. All silylation was carried out at 200 0 C. Columns were coated according to the static method. Freshly prepared, degassed solutions of Dexsil-400 in pentane or methylene chloride were used. Thermal stability of the Dexsil 400 columns with respect to gas chromatography/mass spectrometry (GC/MS) were tested. Column-to-column variability is a function of each step in the fabrication of the columns. The degree of etching, extent of silylation, and stationary phase film thickness must be carefully controlled. The variability in two Dexsil-400 capillary column prepared by etching, silylation with solution of hexa methyl disilazone (HMDS), and static coating is shown and also indicates the excellent selectivity of Dexsil-400 for the separation of alkylated aromatic compounds. The wide temperature range of Dexsil-400 and the high efficiency of the capillary columns also allow the analysis of complex mixtures with minimal prefractionation. Direct injection of a coal liquefaction product is given. Analysis by GC/MS indicated the presence of parent PAHs, alkylated PAHs, nitrogen and sulfur heterocycles, and their alkylated derivatives. 4 figures

  7. Laser surface wakefield in a plasma column

    International Nuclear Information System (INIS)

    Gorbunov, L.M.; Mora, P.; Ramazashvili, R.R.

    2003-01-01

    The structure of the wakefield in a plasma column, produced by a short intense laser pulse, propagating through a gas affected by tunneling ionization is investigated. It is shown that besides the usual plasma waves in the bulk part of the plasma column [see Andreev et al., Phys. Plasmas 9, 3999 (2002)], the laser pulse also generates electromagnetic surface waves propagating along the column boundary. The length of the surface wake wave substantially exceeds the length of the plasma wake wave and its electromagnetic field extends far outside the plasma column

  8. Detection of uranium extraction zone by axial temperature profiles in a pulsed column for Purex process

    International Nuclear Information System (INIS)

    Tsukada, T.; Takahashi, K.

    1991-01-01

    A new method was presented for detecting uranium extraction zone in a pulsed column by means of measuring axial temperature profile originated from reaction heat during uranium extraction. Key parameters of the temperature profiles were estimated with a code developed for calculating temperature profiles in a direct-contact heat exchanger such as a pulsed column, and were verified using data from a small pulsed column simulating reaction heat with injecting hot water. Finally, the results were compared with those from an actual uranium extraction tests, indicating that the method presented was promising for detecting uranium extraction zone in a pulsed column. (author)

  9. Isotopes accumulation in the thermal column of TRIGA reactor

    International Nuclear Information System (INIS)

    Iorgulis, C.; Diaconu, D.; Gugiu, D.; Csaba, R.

    2013-01-01

    The correlation of impurity observed in the virgin graphite and radionuclide content and activities measured in the irradiated graphite needs to know the irradiated history. This is a challenging process if impurity content and irradiation conditions are not accurately known. This is the case of the irradiated graphite in the thermal column of Institute for Nuclear Research Pitesti (INR)14 MW TRIGA reactor. To overcome incomplete impurity content and the unknown position in the column of the measured irradiated graphite available for characterisation and comparison, a set of preliminary simulations were performed. Following Eu 152 /Eu 154 ration they allowed the estimation of an impurity content and irradiation conditions leading to measured activities. Based on these data the radio-isotope accumulation in different positions in the thermal column was predicted. Modelling performed by INR used advanced prediction packages (e.g. WIMS, MCNP ORIGEN-S from Scale 5) to assess the isotopic content of MTR graphite types with irradiation history specific for a TRIGA research reactor. Some certain calculations points from the column were selected in order to model the burnup and isotopes productions using ORIGEN from SCALE code system. (authors)

  10. Refreshment topics II: Design of distillation columns

    Directory of Open Access Journals (Sweden)

    Milojević Svetomir

    2006-01-01

    Full Text Available For distillation column design it is necessary to define all the variable parameters such as component concentrations in different streams temperatures, pressures, mass and energy flow, which are used to represent the separation process of some specific system. They are related to each other according to specific laws, and if the number of such parameters exceeds the number of their relationships, in order to solve a problem some of them must be specified in advance or some constraints assumed for the mass balance, the balance of energy, phase equilibria or chemical equilibria. Knowledge of specific elements which are the constituents of a distillation unit must be known to define the number of design parameters as well as some additional apparati also necessary to realize the distilation. Each separate apparatus might be designed and constructed only if all the necessary and variable parameters for such a unit are defined. This is the right route to solve a distilation unit in many different cases. The construction of some distillation unit requires very good knowledge of mass, heat and momentum transfer phenomena. Moreover, the designer needs to know which kind of apparatus will be used in the distillation unit to realize a specific production process. The most complicated apparatus in a rectification unit is the distillation column. Depending on the complexity of the separation process one, two or more columns are often used. Additional equipment are heat exchangers (reboilers, condensers, cooling systems, heaters, separators, tanks for reflux distribution, tanks and pumps for feed transportation, etc. Such equipment is connected by pipes and valves, and for the normal operation of a distillation unit other instruments for measuring the flow rate, temperature and pressure are also required. Problems which might arise during the determination and selection of such apparati and their number requires knowledge of the specific systems which must

  11. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  12. An all-glass solid sampling device for open tubular columns in gas chromatography

    NARCIS (Netherlands)

    Cox, T.P.H.; vd Berg, P.M.J.

    1972-01-01

    An all-glass system for direct sample-introduction of high-boiling compounds onto open tubular columns is described. The standard deviation for quantitative measurements is less than 2.7%. The loss in resolving power of capillary columns, due to this injection system is negligible. The system is

  13. Carbon dioxide degassing in fresh and saline water I: Degassing performance of a cascade column

    DEFF Research Database (Denmark)

    Moran, Damian

    2010-01-01

    A study was undertaken to measure carbon dioxide degassing in a cascade column operating with both fresh (0‰) and saline water (35‰ NaCl) at 15 °C. The cascade column contained bio-block type packing material, was 1.7 m long in each dimension, and was tested both with and without countercurrent a...

  14. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks

    2012-06-01

    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  15. Gaseous carbon dioxide absorbing column

    International Nuclear Information System (INIS)

    Harashina, Heihachi.

    1994-01-01

    The absorbing column of the present invention comprises a cyclone to which CO 2 gas and Ca(OH) 2 are blown to form CaCO 3 , a water supply means connected to an upper portion of the cyclone for forming a thin water membrane on the inner wall thereof, and a water processing means connected to a lower portion of the cyclone for draining water incorporating CaCO 3 . If a mixed fluid of CO 2 gas and Ca(OH) 2 is blown in a state where a flowing water membrane is formed on the inner wall of the cyclone, formation of CaCO 3 is promoted also in the inside of the cyclone in addition to the formation of CaCO 3 in the course of blowing. Then, formed CaCO 3 is discharged from the lower portion of the cyclone together with downwardly flowing water. With such procedures, solid contents such as CaCO 3 separated at the inner circumferential wall are sent into the thin water membrane, adsorbed and captured, and the solid contents are successively washed out, so that a phenomenon that the solid contents deposit and grow on the inner wall of the cyclone can be prevented effectively. (T.M.)

  16. Rasch models with exchangeable rows and columns

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    The article studies distributions of doubly infinite binary matrices with exchangeable rows and columns which satify the further property that the probability of any $m \\times n$ submatrix is a function of the row- and column sums of that matrix. We show that any such distribution is a (unique...

  17. The general packed column : an analytical solution

    NARCIS (Netherlands)

    Gielen, J.L.W.

    2000-01-01

    The transient behaviour of a packed column is considered. The column, uniformly packed on a macroscopic scale, is multi-structured on the microscopic level: the solid phase consists of particles, which may differ in incidence, shape or size, and other relevant physical properties. Transport in the

  18. Fringing-field effects in acceleration columns

    International Nuclear Information System (INIS)

    Yavor, M.I.; Weick, H.; Wollnik, H.

    1999-01-01

    Fringing-field effects in acceleration columns are investigated, based on the fringing-field integral method. Transfer matrices at the effective boundaries of the acceleration column are obtained, as well as the general transfer matrix of the region separating two homogeneous electrostatic fields with different field strengths. The accuracy of the fringing-field integral method is investigated

  19. Column Chromatography To Obtain Organic Cation Sorption Isotherms.

    Science.gov (United States)

    Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

    2016-08-02

    Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

  20. Boron isotope fractionation in column chromatography with glucamine type fibers

    International Nuclear Information System (INIS)

    Sonoda, Akinari; Makita, Yoji; Hirotsu, Takahiro

    2008-01-01

    Glucamine type polymers have specific affinity toward boric acid and borate ion. Among them, Chelest Fiber GRY-L showed larger fractionation for boron isotopes than other polymers in our previous study. For this study, we used Chelest Fibers with different fiber lengths (1.0 mm, 0.5 mm, and 0.3 mm) as column packing materials to perform chromatographic separation of boron isotopes. The shorter fiber has larger packing density when packed into the column using a dry method. The 0.3-mm-long fiber has a larger backpressure than fibers of other lengths. Boron adsorption capacities were measured using the breakthrough operation. At this time, the 0.5-mm-long fiber showed the highest capacity. When we measured the isotope ratio profile for fibers of different length using column chromatography, 0.5-mm-long fibers displayed the highest boron isotope fractionation. The 0.5-mm-long fiber is promising as a packing material of column chromatography for boron isotope separation. We also changed operation methods. The lower eluent concentration and the slower flow rate are suitable for boron isotope separation. (author)

  1. Experimental Verification of the Structural Glass Beam-Columns Strength

    Science.gov (United States)

    Pešek, Ondřej; Melcher, Jindřich; Balázs, Ivan

    2017-10-01

    This paper deals with experimental research of axially and laterally loaded members made of structural (laminated) glass. The purpose of the research is the evaluation of buckling strength and actual behaviour of the beam-columns due to absence of standards for design of glass load-bearing structures. The experimental research follows the previous one focusing on measuring of initial geometrical imperfections of glass members, testing of glass beams and columns. Within the frame of the research 9 specimens were tested. All of them were of the same geometry (length 2000 mm, width 200 mm and thickness 16 mm) but different composition - laminated double glass made of annealed glass or fully tempered glass panes bonded together by PVB or EVASAFE foil. Specimens were at first loaded by axial force and then by constantly increasing bending moment up to failure. During testing lateral deflections, vertical deflection and normal stresses at mid-span were measured. A maximum load achieved during testing has been adopted as flexural-lateral-torsional buckling strength. The results of experiments were statistically evaluated according to the European standard for design of structures EN 1990, appendix D. There are significant differences between specimens made of annealed glass or fully tempered glass. Differences between specimens loaded by axial forces 1 kN and 2 kN are negligible. The next step was to determine the design strength by calculation procedure based on buckling curves approach intended for design of steel columns and develop interaction criterion for glass beams-columns.

  2. NO2 column changes induced by volcanic eruptions

    Science.gov (United States)

    Johnston, Paul V.; Keys, J. Gordon; Mckenzie, Richard L.

    1994-01-01

    Nitrogen dioxide slant column amounts measured by ground-based remote sensing from Lauder, New Zealand (45 deg S) and Campbell Island (53 deg S) during the second half of 1991 and early 1992 show anomalously low values that are attributed to the effects of volcanic eruptions. It is believed that the eruptions of Mount Pinatubo in the Philippines in June 1991 and possibly Mount Hudson in Chile in August 1991 are responsible for the stratospheric changes, which first became apparent in July 1991. The effects in the spring of 1991 are manifested as a reduction in the retrieved NO2 column amounts from normal levels by 35 to 45 percent, and an accompanying increase in the overnight decay of NO2. The existence of an accurate long-term record of column NO2 from the Lauder site enables us to quantify departures from the normal seasonal behavior with some confidence. Simultaneous retrievals of column ozone agree well with Dobson measurements, confirming that only part of the NO2 changes can be attributed to a modification of the scattering geometry by volcanic aerosols. Other reasons for the observed behavior are explored, including the effects of stratospheric temperature increases resulting from the aerosol loading and the possible involvement of heterogeneous chemical processes.

  3. Godiva, a European Project for Ozone and Trace Gas Measurements from GOME

    Science.gov (United States)

    Goede, A. P. H.; Tanzi, C. P.; Aben, I.; Burrows, J. P.; Weber, M.; Perner, D.; Monks, P. S.; Llewellyn-Jones, D.; Corlett, G. K.; Arlander, D. W.; Platt, U.; Wagner, T.; Pfeilsticker, K.; Taalas, P.; Kelder, H.; Piters, A.

    GODIVA (GOME Data Interpretation, Validation and Application) is a European Commission project aimed at the improvement of GOME (Global Ozone Monitoring Experiment) data products. Existing data products include global ozone, NO2 columns and (ir)radiances. Advanced data products include O3 profiles, BrO, HCHO and OCIO columns. These data are validated by ground-based and balloon borne instruments. Calibration issues are investigated by in-flight monitoring using several complementary calibration sources, as well as an on-ground replica of the GOME instrument. The results will lead to specification of operational processing of the EUMETSAT ozone Satellite Application Facility as well as implementation of the improved and new GOME data products in the NILU database for use in the European THESEO (Third European Stratospheric Experiment on Ozone) campaign of 1999

  4. Hemifield columns co-opt ocular dominance column structure in human achiasma.

    Science.gov (United States)

    Olman, Cheryl A; Bao, Pinglei; Engel, Stephen A; Grant, Andrea N; Purington, Chris; Qiu, Cheng; Schallmo, Michael-Paul; Tjan, Bosco S

    2018-01-01

    In the absence of an optic chiasm, visual input to the right eye is represented in primary visual cortex (V1) in the right hemisphere, while visual input to the left eye activates V1 in the left hemisphere. Retinotopic mapping In V1 reveals that in each hemisphere left and right visual hemifield representations are overlaid (Hoffmann et al., 2012). To explain how overlapping hemifield representations in V1 do not impair vision, we tested the hypothesis that visual projections from nasal and temporal retina create interdigitated left and right visual hemifield representations in V1, similar to the ocular dominance columns observed in neurotypical subjects (Victor et al., 2000). We used high-resolution fMRI at 7T to measure the spatial distribution of responses to left- and right-hemifield stimulation in one achiasmic subject. T 2 -weighted 2D Spin Echo images were acquired at 0.8mm isotropic resolution. The left eye was occluded. To the right eye, a presentation of flickering checkerboards alternated between the left and right visual fields in a blocked stimulus design. The participant performed a demanding orientation-discrimination task at fixation. A general linear model was used to estimate the preference of voxels in V1 to left- and right-hemifield stimulation. The spatial distribution of voxels with significant preference for each hemifield showed interdigitated clusters which densely packed V1 in the right hemisphere. The spatial distribution of hemifield-preference voxels in the achiasmic subject was stable between two days of testing and comparable in scale to that of human ocular dominance columns. These results are the first in vivo evidence showing that visual hemifield representations interdigitate in achiasmic V1 following a similar developmental course to that of ocular dominance columns in V1 with intact optic chiasm. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Center column design of the PLT

    International Nuclear Information System (INIS)

    Citrolo, J.; Frankenberg, J.

    1975-01-01

    The center column of the PLT machine is a secondary support member for the toroidal field coils. Its purpose is to decrease the bending moment at the nose of the coils. The center column design was to have been a stainless steel casting with the toroidal field coils grouped around the casting at installation, trapping it in place. However, the castings developed cracks during fabrication and were unsuitable for use. Installation of the coils proceeded without the center column. It then became necessary to redesign a center column which would be capable of installation with the toroidal field coils in place. The final design consists of three A-286 forgings. This paper discusses the final center column design and the influence that new knowledge, obtained during the power tests, had on the new design

  6. Rotation of a magnesium plasma column in a background gas

    International Nuclear Information System (INIS)

    Bosco, E. Del; Dallaqua, R.S.

    1993-01-01

    Measurements of the angular velocity of a plasma column in a surrounding gas atmosphere are presented. The plasma is produced by a pulsed, high current arc discharge in the presence of an axial magnetic field. The angular velocity is measured using the cross correlation technique applied to the floating potential signals measured by two Langmuir probes. The main result is that when gas is added to the discharge the angular velocity is always lower than the case when there is no gas, this effect been more pronounced in the beginning of the discharge. For pressures higher than ∼ 2 x 10 -2 Pa there is a effect of the gas on the plasma column rotation and the angular velocity diminishes even at the end of discharge. (author)

  7. Collapse of tall granular columns in fluid

    Science.gov (United States)

    Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves

    2017-06-01

    Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

  8. Field Applications of Gamma Column Scanning Technology

    International Nuclear Information System (INIS)

    Aquino, Denis D.; Mallilin, Janice P.; Nuñez, Ivy Angelica A.; Bulos, Adelina DM.

    2015-01-01

    The Isotope Techniques Section (ITS) under the Nuclear Service Division (NSD) of the Philippine Nuclear Research Institute (PNRI) conducts services, research and development on radioisotope and sealed source application in the industry. This aims to benefit the manufacturing industries such as petroleum, petrochemical, chemical, energy, waste, column treatment plant, etc. through on line inspection and troubleshooting of a process vessel, column or pipe that could optimize the process operation and increase production efficiency. One of the most common sealed source techniques for industrial applications is the gamma column scanning technology. Gamma column scanning technology is an established technique for inspection, analysis and diagnosis of industrial columns for process optimization, solving operational malfunctions and management of resources. It is a convenient non-intrusive, cost effective and cost-efficient technique to examine inner details of an industrial process vessel such as a distillation column while it is in operation. The Philippine Nuclear Research Institute (PNRI) recognize the importance and benefits of this technology and has implemented activities to make gamma column scanning locally available to benefit the Philippine industries. Continuous effort for capacity building is being pursued thru the implementation of in-house and on-the-job training abroad and upgrading of equipment. (author)

  9. Metabolic modeling of synthesis gas fermentation in bubble column reactors.

    Science.gov (United States)

    Chen, Jin; Gomez, Jose A; Höffner, Kai; Barton, Paul I; Henson, Michael A

    2015-01-01

    A promising route to renewable liquid fuels and chemicals is the fermentation of synthesis gas (syngas) streams to synthesize desired products such as ethanol and 2,3-butanediol. While commercial development of syngas fermentation technology is underway, an unmet need is the development of integrated metabolic and transport models for industrially relevant syngas bubble column reactors. We developed and evaluated a spatiotemporal metabolic model for bubble column reactors with the syngas fermenting bacterium Clostridium ljungdahlii as the microbial catalyst. Our modeling approach involved combining a genome-scale reconstruction of C. ljungdahlii metabolism with multiphase transport equations that govern convective and dispersive processes within the spatially varying column. The reactor model was spatially discretized to yield a large set of ordinary differential equations (ODEs) in time with embedded linear programs (LPs) and solved using the MATLAB based code DFBAlab. Simulations were performed to analyze the effects of important process and cellular parameters on key measures of reactor performance including ethanol titer, ethanol-to-acetate ratio, and CO and H2 conversions. Our computational study demonstrated that mathematical modeling provides a complementary tool to experimentation for understanding, predicting, and optimizing syngas fermentation reactors. These model predictions could guide future cellular and process engineering efforts aimed at alleviating bottlenecks to biochemical production in syngas bubble column reactors.

  10. Characterization of Bubble Size Distributions within a Bubble Column

    Directory of Open Access Journals (Sweden)

    Shahrouz Mohagheghian

    2018-02-01

    Full Text Available The current study experimentally examines bubble size distribution (BSD within a bubble column and the associated characteristic length scales. Air was injected into a column of water via a single injection tube. The column diameter (63–102 mm, injection tube diameter (0.8–1.6 mm and superficial gas velocity (1.4–55 mm/s were varied. Large samples (up to 54,000 bubbles of bubble sizes measured via 2D imaging were used to produce probability density functions (PDFs. The PDFs were used to identify an alternative length scale termed the most frequent bubble size (dmf and defined as the peak in the PDF. This length scale as well as the traditional Sauter mean diameter were used to assess the sensitivity of the BSD to gas injection rate, injector tube diameter, injection tube angle and column diameter. The dmf was relatively insensitive to most variation, which indicates these bubbles are produced by the turbulent wakes. In addition, the current work examines higher order statistics (standard deviation, skewness and kurtosis and notes that there is evidence in support of using these statistics to quantify the influence of specific parameters on the flow-field as well as a potential indicator of regime transitions.

  11. Bubble Size Distribution in a Vibrating Bubble Column

    Science.gov (United States)

    Mohagheghian, Shahrouz; Wilson, Trevor; Valenzuela, Bret; Hinds, Tyler; Moseni, Kevin; Elbing, Brian

    2016-11-01

    While vibrating bubble columns have increased the mass transfer between phases, a universal scaling law remains elusive. Attempts to predict mass transfer rates in large industrial scale applications by extrapolating laboratory scale models have failed. In a stationary bubble column, mass transfer is a function of phase interfacial area (PIA), while PIA is determined based on the bubble size distribution (BSD). On the other hand, BSD is influenced by the injection characteristics and liquid phase dynamics and properties. Vibration modifies the BSD by impacting the gas and gas-liquid dynamics. This work uses a vibrating cylindrical bubble column to investigate the effect of gas injection and vibration characteristics on the BSD. The bubble column has a 10 cm diameter and was filled with water to a depth of 90 cm above the tip of the orifice tube injector. BSD was measured using high-speed imaging to determine the projected area of individual bubbles, which the nominal bubble diameter was then calculated assuming spherical bubbles. The BSD dependence on the distance from the injector, injector design (1.6 and 0.8 mm ID), air flow rates (0.5 to 5 lit/min), and vibration conditions (stationary and vibration conditions varying amplitude and frequency) will be presented. In addition to mean data, higher order statistics will also be provided.

  12. Dynamic effects of diabatization in distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2013-01-01

    The dynamic effects of diabatization in distillation columns are investigated in simulation emphasizing the heat-integrated distillation column (HIDiC). A generic, dynamic, first-principle model has been formulated, which is flexible enough to describe various diabatic distillation configurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found and control...

  13. Dynamic Effects of Diabatization in Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2012-01-01

    The dynamic eects of diabatization in distillation columns are investigated in simulation with primary focus on the heat-integrated distillation column (HIDiC). A generic, dynamic, rst-principle model has been formulated, which is exible to describe various diabatic distillation congurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found. Control...

  14. Column-oriented database management systems

    OpenAIRE

    Možina, David

    2013-01-01

    In the following thesis I will present column-oriented database. Among other things, I will answer on a question why there is a need for a column-oriented database. In recent years there have been a lot of attention regarding a column-oriented database, even if the existence of a columnar database management systems dates back in the early seventies of the last century. I will compare both systems for a database management – a colum-oriented database system and a row-oriented database system ...

  15. Anomalous electrical signals associated with microbial activity: Results from Iron and Nitrate-Reducing Columns

    Science.gov (United States)

    Aaron, R. B.; Zheng, Q.; Flynn, P.; Singha, K.; Brantley, S.

    2008-12-01

    Three flow-through columns outfitted with Ag/AgCl electrodes were constructed to test the effects of different microbial processes on the geophysical measurements of self potential (SP), bulk electrical conductivity (σ b), and induced polarization (IP). The columns were filled with sieved, Fe-bearing subsurface sediment from the Delmarva Peninsula near Oyster, VA, inoculated (9:1 ratio) with a freshly-collected, shallow subsurface sediment from a wetland floodplain (Dorn Creek) near Madison, WI. Each of the columns was fed anoxic and sterile PIPES buffered artificial groundwater (PBAGW) containing different concentrations of acetate and nitrate. The medium fed to Column 1 (nitrate-reducing) was amended with 100 μM acetate and 2 mM nitrate. Column 2 (iron-reducing) was run with PBAGW containing 1.0 mM acetate and 0 mM nitrate. Column 3 (alternating redox state) was operated under conditions designed to alternately stimulate nitrate-reducing and iron-reducing populations to provide conditions, i.e., the presence of both nitrate and microbially-produced Fe(II), that would allow growth of nitrate-dependent Fe(II)-oxidizing populations. We operated Column 3 with a cycling strategy of 14-18 days of high C medium (1 mM acetate and 100 μ M nitrate) followed by 14-18 days of low C medium (100 μ M acetate and 2 mM nitrate). Effluent chemistry (NO3-, NO2-, NH4+, acetate, and Fe2+) was sampled daily for four months so as to be concurrent with the electrical measurements. We observed chemical evidence of iron reduction (dissolved [Fe(II)] = 0.2mM) in the effluent from the iron reduction and alternating redox columns. Chemical depletion of NO3- ([NO3-] ranged from 1 to 0.02mM), the production of NO2-, and possible production of NH4+ (0.2 mM) was observed in the nitrate reducing column as well as the alternating redox column. All three columns displayed loss of acetate as microbial activity progressed. σ b remained constant in the alternating redox column (~0.15 S

  16. Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data

    Directory of Open Access Journals (Sweden)

    N. Spichtinger

    2004-01-01

    Full Text Available Forest fire emissions have a strong impact on the concentrations of trace gases and aerosols in the atmosphere. In order to quantify the influence of boreal forest fire emissions on the atmospheric composition, the fire seasons of 1997 and 1998 are compared in this paper. Fire activity in 1998 was very strong, especially over Canada and Eastern Siberia, whereas it was much weaker in 1997. According to burned area estimates the burning in 1998 was more than six times as intense as in 1997. Based on hot spot locations derived from ATSR (Along Track Scanning Radiometer data and official burned area data, fire emissions were estimated and their transport was simulated with a Lagrangian tracer transport model. Siberian and Canadian forest fire tracers were distinguished to investigate the transport of both separately. The fire emissions were transported even over intercontinental distances. Due to the El Niño induced meteorological situation, transport from Siberia to Canada was enhanced in 1998. Siberian fire emissions were transported towards Canada and contributed concentrations more than twice as high as those due to Canada's own CO emissions by fires. In 1998 both tracers arrive at higher latitudes over Europe, which is due to a higher North Atlantic Oscillation (NAO index in 1998. The simulated emission plumes are compared to CMDL (Climate Monitoring and Diagnostics Laboratory CO2 and CO data, Total Ozone Mapping Spectrometer (TOMS aerosol index (AI data and Global Ozone Monitoring Experiment (GOME tropospheric NO2 and HCHO columns. All the data show clearly enhanced signals during the burning season of 1998 compared to 1997. The results of the model simulation are in good agreement with ground-based as well as satellite-based measurements.

  17. Family of columns isospectral to gravity-loaded columns with tip force: A discrete approach

    Science.gov (United States)

    Ramachandran, Nirmal; Ganguli, Ranjan

    2018-06-01

    A discrete model is introduced to analyze transverse vibration of straight, clamped-free (CF) columns of variable cross-sectional geometry under the influence of gravity and a constant axial force at the tip. The discrete model is used to determine critical combinations of loading parameters - a gravity parameter and a tip force parameter - that cause onset of dynamic instability in the CF column. A methodology, based on matrix-factorization, is described to transform the discrete model into a family of models corresponding to weightless and unloaded clamped-free (WUCF) columns, each with a transverse vibration spectrum isospectral to the original model. Characteristics of models in this isospectral family are dependent on three transformation parameters. A procedure is discussed to convert the isospectral discrete model description into geometric description of realistic columns i.e. from the discrete model, we construct isospectral WUCF columns with rectangular cross-sections varying in width and depth. As part of numerical studies to demonstrate efficacy of techniques presented, frequency parameters of a uniform column and three types of tapered CF columns under different combinations of loading parameters are obtained from the discrete model. Critical combinations of these parameters for a typical tapered column are derived. These results match with published results. Example CF columns, under arbitrarily-chosen combinations of loading parameters are considered and for each combination, isospectral WUCF columns are constructed. Role of transformation parameters in determining characteristics of isospectral columns is discussed and optimum values are deduced. Natural frequencies of these WUCF columns computed using Finite Element Method (FEM) match well with those of the given gravity-loaded CF column with tip force, hence confirming isospectrality.

  18. Unbonded Prestressed Columns for Earthquake Resistance

    Science.gov (United States)

    2012-05-01

    Modern structures are able to survive significant shaking caused by earthquakes. By implementing unbonded post-tensioned tendons in bridge columns, the damage caused by an earthquake can be significantly lower than that of a standard reinforced concr...

  19. HPLC separation of triacylglycerol positional isomers on a polymeric ODS column.

    Science.gov (United States)

    Kuroda, Ikuma; Nagai, Toshiharu; Mizobe, Hoyo; Yoshimura, Nobuhito; Gotoh, Naohiro; Wada, Shun

    2008-07-01

    A polymeric ODS column was applied to the resolution of triacylglycerol positional isomers (TAG-PI), i.e. 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (OOP), with a recycle HPLC system. To investigate the ODS column species and the column temperatures for the resolution of a TAG-PI pair, a mixture of OPO and OOP was subjected to an HPLC system equipped with a non-endcapped polymeric, endcapped monomeric, endcapped intermediate, or non-endcapped monomeric ODS column at three different column temperatures (40, 25, or 10 degrees C). Only the non-endcapped polymeric ODS column achieved the separation of OPO and OOP, and the lowest column temperature (10 degrees C) showed the best resolution for them. The other pair of TAG-PI, a mixture of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP) and 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (PPO) was also subjected to the system equipped with a non-endcapped polymeric or monomeric ODS column at five different column temperatures (40, 32, 25, 17, and 10 degrees C). Thus, POP and PPO were also separated on only the non-endcapped polymeric ODS column at 25 degrees C. However, no clear peak appeared at 10 degrees C. These results would indicate that the polymeric ODS stationary phase has an ability to recognize the structural differences between TAG-PI pairs. Also, the column temperature is a very important factor for separating the TAG-PI pair, and the optimal temperature would relate to the solubility of TAG-PI in the mobile phase. Furthermore, the recycle HPLC system provided measurements for the separation and analysis of TAG-PI pairs.

  20. [Online enrichment ability of restricted-access column coupled with high performance liquid chromatography by column switching technique for benazepril hydrochloride].

    Science.gov (United States)

    Zhang, Xiaohui; Wang, Rong; Xie, Hua; Yin, Qiang; Li, Xiaoyun; Jia, Zhengping; Wu, Xiaoyu; Zhang, Juanhong; Li, Wenbin

    2013-05-01

    The online enrichment ability of the restricted-access media (RAM) column coupled with high performance liquid chromatography by column switching technique for benazepril hydrochloride in plasma was studied. The RAM-HPLC system consisted of an RAM column as enrichment column and a C18 column as analytical column coupled via the column switching technique. The effects of the injection volume on the peak area and the systematic pressure were studied. When the injection volume was less than 100 microL, the peak area increased with the increase of the injection volume. However, when the injection volume was more than 80 microL, the pressure of whole system increased obviously. In order to protect the whole system, 80 microL was chosen as the maximum injection volume. The peak areas of ordinary injection and the large volume injection showed a good linear relationship. The enrichment ability of RAM-HPLC system was satisfactory. The system was successfully used for the separation and detection of the trace benazepril hydrochloride in rat plasma after its administration. The sensitivity of HPLC can be improved by RAM pre-enrichment. It is a simple and economic measurement method.

  1. SPR Hydrostatic Column Model Verification and Validation.

    Energy Technology Data Exchange (ETDEWEB)

    Bettin, Giorgia [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lord, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rudeen, David Keith [Gram, Inc. Albuquerque, NM (United States)

    2015-10-01

    A Hydrostatic Column Model (HCM) was developed to help differentiate between normal "tight" well behavior and small-leak behavior under nitrogen for testing the pressure integrity of crude oil storage wells at the U.S. Strategic Petroleum Reserve. This effort was motivated by steady, yet distinct, pressure behavior of a series of Big Hill caverns that have been placed under nitrogen for extended period of time. This report describes the HCM model, its functional requirements, the model structure and the verification and validation process. Different modes of operation are also described, which illustrate how the software can be used to model extended nitrogen monitoring and Mechanical Integrity Tests by predicting wellhead pressures along with nitrogen interface movements. Model verification has shown that the program runs correctly and it is implemented as intended. The cavern BH101 long term nitrogen test was used to validate the model which showed very good agreement with measured data. This supports the claim that the model is, in fact, capturing the relevant physical phenomena and can be used to make accurate predictions of both wellhead pressure and interface movements.

  2. Capacity of columns with splice imperfections

    International Nuclear Information System (INIS)

    Popov, E.P.; Stephen, R.M.

    1977-01-01

    To study the behavior of spliced columns subjected to tensile forces simulating situations which may develop in an earthquake, all of the spliced specimens were tested to failure in tension after first having been subjected to large compressive loads. The results of these tests indicate that the lack of perfect contact at compression splices of columns may not be important, provided that the gaps are shimmed and welding is used to maintain the sections in alignment

  3. Study on the runout of granular columns with SPH methods.

    OpenAIRE

    He, Xuzhen; Liang, Dongfang

    2015-01-01

    Landslides are catastrophic geophysical phenomena, which may cause heavy fatality and property losses. Hence, it is of vital importance to understand their mechanisms and evaluate their travel distance, so that appropriate measures can be taken to mitigate their risk. This paper reports on an application of the incompressible Smoothed Particle Hydrodynamics (SPH) method to the simulation of the collapse of granular columns onto the planes of different slopes, which is similar to dry landslide...

  4. Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments

    Science.gov (United States)

    Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

  5. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

    Science.gov (United States)

    Huz, Kateryna

    2014-01-01

    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  6. The handedness of historiated spiral columns.

    Science.gov (United States)

    Couzin, Robert

    2017-09-01

    Trajan's Column in Rome (AD 113) was the model for a modest number of other spiral columns decorated with figural, narrative imagery from antiquity to the present day. Most of these wind upwards to the right, often with a congruent spiral staircase within. A brief introductory consideration of antique screw direction in mechanical devices and fluted columns suggests that the former may have been affected by the handedness of designers and the latter by a preference for symmetry. However, for the historiated columns that are the main focus of this article, the determining factor was likely script direction. The manner in which this operated is considered, as well as competing mechanisms that might explain exceptions. A related phenomenon is the reversal of the spiral in a non-trivial number of reproductions of the antique columns, from Roman coinage to Renaissance and baroque drawings and engravings. Finally, the consistent inattention in academic literature to the spiral direction of historiated columns and the repeated publication of erroneous earlier reproductions warrants further consideration.

  7. Integrated Multiscale Latent Variable Regression and Application to Distillation Columns

    Directory of Open Access Journals (Sweden)

    Muddu Madakyaru

    2013-01-01

    Full Text Available Proper control of distillation columns requires estimating some key variables that are challenging to measure online (such as compositions, which are usually estimated using inferential models. Commonly used inferential models include latent variable regression (LVR techniques, such as principal component regression (PCR, partial least squares (PLS, and regularized canonical correlation analysis (RCCA. Unfortunately, measured practical data are usually contaminated with errors, which degrade the prediction abilities of inferential models. Therefore, noisy measurements need to be filtered to enhance the prediction accuracy of these models. Multiscale filtering has been shown to be a powerful feature extraction tool. In this work, the advantages of multiscale filtering are utilized to enhance the prediction accuracy of LVR models by developing an integrated multiscale LVR (IMSLVR modeling algorithm that integrates modeling and feature extraction. The idea behind the IMSLVR modeling algorithm is to filter the process data at different decomposition levels, model the filtered data from each level, and then select the LVR model that optimizes a model selection criterion. The performance of the developed IMSLVR algorithm is illustrated using three examples, one using synthetic data, one using simulated distillation column data, and one using experimental packed bed distillation column data. All examples clearly demonstrate the effectiveness of the IMSLVR algorithm over the conventional methods.

  8. Irradiation facilities on the TRIGA-SSR thermal column

    Energy Technology Data Exchange (ETDEWEB)

    Roth, C; Aioanei, L; Preda, M; Gugiu, D [Institute for Nuclear Research, Pitesti (Romania); Garlea, I; Kelerman, C; Garlea, C [SENDRA ' Nuclear Technologies' ltd. Bucharest (Romania)

    2004-07-01

    The development of thermal and intermediate energy neutron irradiation facilities at the steady state core of the Romanian TRIGA Reactor is described. The reference thermal neutron irradiation facility consists of a dry spherical cavity placed into the graphite thermal column of the SSR core and the intermediate energy neutron irradiation facility is a {sigma}{sigma} system located into the thermal flux cavity. The implementation of the irradiation facilities into the under-water thermal column represented an important challenge from the standpoint of instrumentation solutions. The neutron flux and spectrum measurements were performed using foil activation techniques and fission rate measurements by sealed fission chambers, followed by spectrum unfolding procedure. The absolute fission reaction measurements, using calibrated fission chambers, allow the neutron flux density unit transfer from international reference neutron fields. The MCNP-4C code package was used for neutron spectrum computations in the thermal flux cavity and in the {sigma}{sigma} system. The neutron characterization program demonstrates the accuracy of the spectrum characteristics and neutron flux densities reported to the local monitoring system count rates. Some discrepancies, as compared to other similar facilities, were identified and discussed. These are caused by thermal column particularities: the presence of a water layer between the graphite cells (thermal neutron absorption) and smaller geometrical dimensions (neutron escape phenomena). Based on these results the metrological certification process, according to Romanian metrological laws requirements, is now in progress. (nevyjel)

  9. Mass transfer model liquid phase catalytic exchange column simulation applicable to any column composition profile

    Energy Technology Data Exchange (ETDEWEB)

    Busigin, A. [NITEK USA Inc., Ocala, FL (United States)

    2015-03-15

    Liquid Phase Catalytic Exchange (LPCE) is a key technology used in water detritiation systems. Rigorous simulation of LPCE is complicated when a column may have both hydrogen and deuterium present in significant concentrations in different sections of the column. This paper presents a general mass transfer model for a homogenous packed bed LPCE column as a set of differential equations describing composition change, and equilibrium equations to define the mass transfer driving force within the column. The model is used to show the effect of deuterium buildup in the bottom of an LPCE column from non-negligible D atom fraction in the bottom feed gas to the column. These types of calculations are important in the design of CECE (Combined Electrolysis and Catalytic Exchange) water detritiation systems.

  10. Development of spent salt treatment technology by zeolite column system. Performance evaluation of zeolite column

    International Nuclear Information System (INIS)

    Miura, Hidenori; Uozumi, Koichi

    2009-01-01

    At electrorefining process, fission products(FPs) accumulate in molten salt. To avoid influence on heating control by decay heat and enlargement of FP amount in the recovered fuel, FP elements must be removed from the spent salt of the electrorefining process. For the removal of the FPs from the spent salt, we are investigating the availability of zeolite column system. For obtaining the basic data of the column system, such as flow property and ion-exchange performance while high temperature molten salt is passing through the column, and experimental apparatus equipped with fraction collector was developed. By using this apparatus, following results were obtained. 1) We cleared up the flow parameter of column system with zeolite powder, such as flow rate control by argon pressure. 2) Zeolite 4A in the column can absorb cesium that is one of the FP elements in molten salt. From these results, we got perspective on availability of the zeolite column system. (author)

  11. Design concept of a cryogenic distillation column cascade for a ITER scale fusion reactor

    Science.gov (United States)

    Yamanishi, Toshihiko; Enoeda, Mikio; Okuno, Kenji

    1994-07-01

    A column cascade has been proposed for the fuel cycle of a ITER scale fusion reactor. The proposed cascade consists of three columns and has significant features: either top or bottom product is prior to the other for each column; it is avoided to withdraw side streams as products or feeds of down stream columns; and there is no recycle steam between the columns. In addition, the product purity of the cascade can be maintained against the changes of flow rates and compositions of feed streams just by adjusting the top and bottom flow rates. The control system has been designed for each column in the cascade. A key component in the prior product stream was selected, and the analysis method of this key component was proposed. The designed control system never brings instability as long as the concentration of the key component is measured with negligible time lag. The time lag for the measurement considerably affects the stability of the control system. A significant conclusion by the simulation in this work is that permissible time for the measurement is about 0.5 hour to obtain stable control. Hence, the analysis system using the gas chromatography is valid for control of the columns.

  12. Design concept of a cryogenic distillation column cascade for a ITER scale fusion reactor

    International Nuclear Information System (INIS)

    Yamanishi, Toshihiko; Enoeda, Mikio; Okuno, Kenji

    1994-07-01

    A column cascade has been proposed for the fuel cycle of a ITER scale fusion reactor. The proposed cascade consists of three columns and has significant features: either top or bottom product is prior to the other for each column: it is avoided to withdraw side streams as products or feeds of down stream columns: and there is no recycle steam between the columns. In addition, the product purity of the cascade can be maintained against the changes of flow rates and compositions of feed streams just by adjusting the top and bottom flow rates. The control system has been designed for each column in the cascade. A key component in the prior product stream was selected, and the analysis method of this key component was proposed. The designed control system never brings instability as long as the concentration of the key component is measured with negligible time lag. The time lag for the measurement considerably affects the stability of the control system. A significant conclusion by the simulation in this work is that permissible time for the measurement is about 0.5 hour to obtain stable control. Hence, the analysis system using the gas chromatography is valid for control of the columns. (author)

  13. Structural Decoupling and Disturbance Rejection in a Distillation Column

    DEFF Research Database (Denmark)

    Bahar, Mehrdad; Jantzen, Jan; Commault, C.

    1996-01-01

    Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....

  14. Using satellite-based measurements to explore ...

    Science.gov (United States)

    New particle formation (NPF) can potentially alter regional climate by increasing aerosol particle (hereafter particle) number concentrations and ultimately cloud condensation nuclei. The large scales on which NPF is manifest indicate potential to use satellite-based (inherently spatially averaged) measurements of atmospheric conditions to diagnose the occurrence of NPF and NPF characteristics. We demonstrate the potential for using satellite-measurements of insolation (UV), trace gas concentrations (sulfur dioxide (SO2), nitrogen dioxide (NO2), ammonia (NH3), formaldehyde (HCHO), ozone (O3)), aerosol optical properties (aerosol optical depth (AOD), Ångström exponent (AE)), and a proxy of biogenic volatile organic compound emissions (leaf area index (LAI), temperature (T)) as predictors for NPF characteristics: formation rates, growth rates, survival probabilities, and ultrafine particle (UFP) concentrations at five locations across North America. NPF at all sites is most frequent in spring, exhibits a one-day autocorrelation, and is associated with low condensational sink (AOD×AE) and HCHO concentrations, and high UV. However, there are important site-to-site variations in NPF frequency and characteristics, and in which of the predictor variables (particularly gas concentrations) significantly contribute to the explanatory power of regression models built to predict those characteristics. This finding may provide a partial explanation for the reported spatia

  15. Column Selection for Biomedical Analysis Supported by Column Classification Based on Four Test Parameters.

    Science.gov (United States)

    Plenis, Alina; Rekowska, Natalia; Bączek, Tomasz

    2016-01-21

    This article focuses on correlating the column classification obtained from the method created at the Katholieke Universiteit Leuven (KUL), with the chromatographic resolution attained in biomedical separation. In the KUL system, each column is described with four parameters, which enables estimation of the FKUL value characterising similarity of those parameters to the selected reference stationary phase. Thus, a ranking list based on the FKUL value can be calculated for the chosen reference column, then correlated with the results of the column performance test. In this study, the column performance test was based on analysis of moclobemide and its two metabolites in human plasma by liquid chromatography (LC), using 18 columns. The comparative study was performed using traditional correlation of the FKUL values with the retention parameters of the analytes describing the column performance test. In order to deepen the comparative assessment of both data sets, factor analysis (FA) was also used. The obtained results indicated that the stationary phase classes, closely related according to the KUL method, yielded comparable separation for the target substances. Therefore, the column ranking system based on the FKUL-values could be considered supportive in the choice of the appropriate column for biomedical analysis.

  16. Improving the accuracy of S02 column densities and emission rates obtained from upward-looking UV-spectroscopic measurements of volcanic plumes by taking realistic radiative transfer into account

    Science.gov (United States)

    Kern, Christoph; Deutschmann, Tim; Werner, Cynthia; Sutton, A. Jeff; Elias, Tamar; Kelly, Peter J.

    2012-01-01

    Sulfur dioxide (SO2) is monitored using ultraviolet (UV) absorption spectroscopy at numerous volcanoes around the world due to its importance as a measure of volcanic activity and a tracer for other gaseous species. Recent studies have shown that failure to take realistic radiative transfer into account during the spectral retrieval of the collected data often leads to large errors in the calculated emission rates. Here, the framework for a new evaluation method which couples a radiative transfer model to the spectral retrieval is described. In it, absorption spectra are simulated, and atmospheric parameters are iteratively updated in the model until a best match to the measurement data is achieved. The evaluation algorithm is applied to two example Differential Optical Absorption Spectroscopy (DOAS) measurements conducted at Kilauea volcano (Hawaii). The resulting emission rates were 20 and 90% higher than those obtained with a conventional DOAS retrieval performed between 305 and 315 nm, respectively, depending on the different SO2 and aerosol loads present in the volcanic plume. The internal consistency of the method was validated by measuring and modeling SO2 absorption features in a separate wavelength region around 375 nm and comparing the results. Although additional information about the measurement geometry and atmospheric conditions is needed in addition to the acquired spectral data, this method for the first time provides a means of taking realistic three-dimensional radiative transfer into account when analyzing UV-spectral absorption measurements of volcanic SO2 plumes.

  17. DISCOVER-AQ Airborne Measurements Quantify How Satellite-Retrievable Becomes Health-Relevant: The Example Of Smog And Its Production

    Science.gov (United States)

    Esswein, R. F.; Chatfield, R. B.; Crawford, J. H.; Weinheimer, A. J.; Fried, A.; Barrick, J. D.

    2012-12-01

    Unusually rich information about health-relevant surface smog pollution may be expected from developing multi-wavelength retrievals from space, e.g., in upcoming missions being planned by the United States ("GEO-CAPE") and by European and Asian agencies. The key is that ozone and its precursors are vertically correlated in layers that can be retrieved, and that situation-to-situation variation is more important than small local spatial variations. Variations in relationships are understood in terms of simple weather principles such as subsidence and repeating local circulation features. BACKGROUND: Near-surface pollution is one of the most challenging problems for Earth observations from space. Near- surface information must be inferred from column-integrated quantities obtained by passive remote sensing from nadir-looking satellite instruments. NASA has undertaken a major five-year experimental mission to investigate air pollution on the 1- to 100-km urban/regional scale. The mission concept involved Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality, generally known better by its acronym DISCOVER-AQ. A major goal is to understand the usefulness of and best methodologies for satellite remote sensing data. The DISCOVER-AQ airborne study repeatedly made spirals over various urban, industrial, transportation, and rural sites in detail around the Baltimore-Washington area in July, 2011. We compare mixing ratios appropriately averaged over a 0.2-3 km altitude ("Retrievable") and those measured at the bottom of the spirals, 0.2-0.5 km, the "Relevant". The "Retrievable" layer 0.2-3 km. was set by GEO-CAPE remote- sensing sensitivity analyses for ozone [Natraj et al., Atmos. Environ., 2011]. Correlations were quite good, ca. 0.9. Retrieved-relevant correlations for O3 were determined mostly by synoptic conditions. Comparisons for NO2 and HCHO mixing ratio (= m.r.) and especially log(m.r.) are affected by

  18. Recent advances in column switching sample preparation in bioanalysis.

    Science.gov (United States)

    Kataoka, Hiroyuki; Saito, Keita

    2012-04-01

    Column switching techniques, using two or more stationary phase columns, are useful for trace enrichment and online automated sample preparation. Target fractions from the first column are transferred online to a second column with different properties for further separation. Column switching techniques can be used to determine the analytes in a complex matrix by direct sample injection or by simple sample treatment. Online column switching sample preparation is usually performed in combination with HPLC or capillary electrophoresis. SPE or turbulent flow chromatography using a cartridge column and in-tube solid-phase microextraction using a capillary column have been developed for convenient column switching sample preparation. Furthermore, various micro-/nano-sample preparation devices using new polymer-coating materials have been developed to improve extraction efficiency. This review describes current developments and future trends in novel column switching sample preparation in bioanalysis, focusing on innovative column switching techniques using new extraction devices and materials.

  19. SLIP VELOCITY IN PULSED DISC AND DOUGHNUT EXTRACTION COLUMN

    Directory of Open Access Journals (Sweden)

    Mohammad Outokesh

    2011-09-01

    Full Text Available In the present work, slip velocity has been measured in a 76 mm diameter pulsed disc and doughnut extraction column for four different liquid-liquid systems. The effects of operating variables including pulsation intensity and dispersed and continuous phase flow rates on slip velocity have been investigated. The existence of three different operational regimes, namely mixersettler, transition, and emulsion regimes, was observed when the energy input was changed. Empirical correlations are derived for prediction of the slip velocity in terms of operating variables, physical properties of the liquid systems, and column geometry for different regimes. Good agreement between prediction and experiments was found for all operating conditions that were investigated.

  20. Current status of crushed rock and whole rock column studies

    International Nuclear Information System (INIS)

    Vine, E.N.; Daniels, W.R.; Rundberg, R.S.; Thompson, J.L.

    1980-01-01

    Measurements on a large number of crushed rock columns of tuff, granite, and argillite are discussed. The isotopes 85 Sr, 137 Cs, 133 Ba, 141 Ce, 152 Eu, /sup 95m/Tc, and 233 U were used. Flow rates were varied from approx. 30 to approx. 30000 m/y. Other parameters studied include isotope concentration and atmosphere. The sorption ratios calculated were compared with batch sorption ratios on the same samples. Methods of studying the movement of radionuclides through whole rock cores are described. The problems associated with sealing the cores to prevent leaking along the exterior surface and one possible solution are discussed. The strontium sorption ratio obtained by elution of one solid tuff core is compared with the batch and crushed rock column sorption ratios

  1. Finite length thermal equilibria of a pure electron plasma column

    International Nuclear Information System (INIS)

    Prasad, S.A.; O'Neil, T.M.

    1979-01-01

    The electrons of a pure electron plasma may be in thermal equilibrium with each other and still be confined by static magnetic and electric fields. Since the electrons make a significant contribution to the electric field, only certain density profiles are consistent with Poisson's equation. The class of such distributions for a finite length cylindrical column is investigated. In the limit where the Debye length is small compared with the dimensions of the column, the density is essentially constant out to some surface of revolution and then falls off abruptly. The falloff in density is a universal function when measured along the local normal to the surface of revolution and scaled in terms of the Debye length. The solution for the shape of the surface of revolution is simplified by passage to the limit of zero Debye length

  2. Using solvent extraction to process nitrate anion exchange column effluents

    International Nuclear Information System (INIS)

    Yarbro, S.L.

    1987-10-01

    Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO), a new organophosphorous extractant, and a new centrifugal mixer-settler both recently developed at Argonne were evaluated for their potential use in the recovery of actinides from nitrate anion exchange column effluents. The performance of the extractant was evaluated by measuring the extraction coefficient values as a function of acid and salt concentration. Additional performance parameters include extraction coefficient behavior as a function of the total metal concentration in the organic phase, and comparison of different stripping and organic scrubbing techniques. A simulated effluent stream was used to evaluate the performance of the centrifugal mixer-settlers by comparing experimental and calculated interstage concentration profiles. Both the CMPO extractant and the centrifugal mixer-settlers have potential for processing nitrate column effluents, particularly if the stripping behavior can be improved. Details of the proposed process are presented in the flowsheet and contactor design analyses

  3. Using solvent extraction to process nitrate anion exchange column effluents

    Energy Technology Data Exchange (ETDEWEB)

    Yarbro, S.L.

    1987-10-01

    Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO), a new organophosphorous extractant, and a new centrifugal mixer-settler both recently developed at Argonne were evaluated for their potential use in the recovery of actinides from nitrate anion exchange column effluents. The performance of the extractant was evaluated by measuring the extraction coefficient values as a function of acid and salt concentration. Additional performance parameters include extraction coefficient behavior as a function of the total metal concentration in the organic phase, and comparison of different stripping and organic scrubbing techniques. A simulated effluent stream was used to evaluate the performance of the centrifugal mixer-settlers by comparing experimental and calculated interstage concentration profiles. Both the CMPO extractant and the centrifugal mixer-settlers have potential for processing nitrate column effluents, particularly if the stripping behavior can be improved. Details of the proposed process are presented in the flowsheet and contactor design analyses.

  4. Comparative study of the performance of columns packed with several new fine silica particles. Would the external roughness of the particles affect column properties?

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2007-09-28

    We measured and compared the characteristics and performance of columns packed with particles of five different C(18)-bonded silica, 3 and 5 microm Luna, 3 microm Atlantis, 3.5 microm Zorbax, and 2.7 microm Halo. The average particle size of each material was derived from the SEM pictures of 200 individual particles. These pictures contrast the irregular morphology of the external surface of the Zorbax and Halo particles and the smooth surface of the Luna and Atlantis particles. In a wide range of mobile phase velocities (from 0.010 to 3 mL/min) and at ambient temperature, we measured the first and second central moments of the peaks of naphthalene, insulin, and bovine serum albumin (BSA). These moments were corrected for the contributions of the extra-column volumes to calculate the reduced HETPs. The C-terms of naphthalene and insulin are largest for the Halo and Zorbax materials and the A-term smallest for the Halo-packed column. The Halo column performs the best for the low molecular weight compound naphthalene (minimum reduced HETP, 1.4) but is not as good as the Atlantis or Luna columns for the large molecular weight compound insulin. The Zorbax column is the least efficient column because of its large C-term. The lowest sample diffusivity through these particles, alone, does not account for the results. It is most likely that the roughness of the external surface of the Halo and Zorbax particles limit the performance of these columns at high flow rates generating an unusually high film mass transfer resistance.

  5. Contributions to reversed-phase column selectivity: III. Column hydrogen-bond basicity.

    Science.gov (United States)

    Carr, P W; Dolan, J W; Dorsey, J G; Snyder, L R; Kirkland, J J

    2015-05-22

    Column selectivity in reversed-phase chromatography (RPC) can be described in terms of the hydrophobic-subtraction model, which recognizes five solute-column interactions that together determine solute retention and column selectivity: hydrophobic, steric, hydrogen bonding of an acceptor solute (i.e., a hydrogen-bond base) by a stationary-phase donor group (i.e., a silanol), hydrogen bonding of a donor solute (e.g., a carboxylic acid) by a stationary-phase acceptor group, and ionic. Of these five interactions, hydrogen bonding between donor solutes (acids) and stationary-phase acceptor groups is the least well understood; the present study aims at resolving this uncertainty, so far as possible. Previous work suggests that there are three distinct stationary-phase sites for hydrogen-bond interaction with carboxylic acids, which we will refer to as column basicity I, II, and III. All RPC columns exhibit a selective retention of carboxylic acids (column basicity I) in varying degree. This now appears to involve an interaction of the solute with a pair of vicinal silanols in the stationary phase. For some type-A columns, an additional basic site (column basicity II) is similar to that for column basicity I in primarily affecting the retention of carboxylic acids. The latter site appears to be associated with metal contamination of the silica. Finally, for embedded-polar-group (EPG) columns, the polar group can serve as a proton acceptor (column basicity III) for acids, phenols, and other donor solutes. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. ON THE ORIGIN OF THE HIGH COLUMN DENSITY TURNOVER IN THE H I COLUMN DENSITY DISTRIBUTION

    International Nuclear Information System (INIS)

    Erkal, Denis; Gnedin, Nickolay Y.; Kravtsov, Andrey V.

    2012-01-01

    We study the high column density regime of the H I column density distribution function and argue that there are two distinct features: a turnover at N H I ≈ 10 21 cm –2 , which is present at both z = 0 and z ≈ 3, and a lack of systems above N H I ≈ 10 22 cm –2 at z = 0. Using observations of the column density distribution, we argue that the H I-H 2 transition does not cause the turnover at N H I ≈ 10 21 cm –2 but can plausibly explain the turnover at N H I ∼> 10 22 cm –2 . We compute the H I column density distribution of individual galaxies in the THINGS sample and show that the turnover column density depends only weakly on metallicity. Furthermore, we show that the column density distribution of galaxies, corrected for inclination, is insensitive to the resolution of the H I map or to averaging in radial shells. Our results indicate that the similarity of H I column density distributions at z = 3 and 0 is due to the similarity of the maximum H I surface densities of high-z and low-z disks, set presumably by universal processes that shape properties of the gaseous disks of galaxies. Using fully cosmological simulations, we explore other candidate physical mechanisms that could produce a turnover in the column density distribution. We show that while turbulence within giant molecular clouds cannot affect the damped Lyα column density distribution, stellar feedback can affect it significantly if the feedback is sufficiently effective in removing gas from the central 2-3 kpc of high-redshift galaxies. Finally, we argue that it is meaningful to compare column densities averaged over ∼ kpc scales with those estimated from quasar spectra that probe sub-pc scales due to the steep power spectrum of H I column density fluctuations observed in nearby galaxies.

  7. Vertebral Column Resection for Rigid Spinal Deformity.

    Science.gov (United States)

    Saifi, Comron; Laratta, Joseph L; Petridis, Petros; Shillingford, Jamal N; Lehman, Ronald A; Lenke, Lawrence G

    2017-05-01

    Broad narrative review. To review the evolution, operative technique, outcomes, and complications associated with posterior vertebral column resection. A literature review of posterior vertebral column resection was performed. The authors' surgical technique is outlined in detail. The authors' experience and the literature regarding vertebral column resection are discussed at length. Treatment of severe, rigid coronal and/or sagittal malalignment with posterior vertebral column resection results in approximately 50-70% correction depending on the type of deformity. Surgical site infection rates range from 2.9% to 9.7%. Transient and permanent neurologic injury rates range from 0% to 13.8% and 0% to 6.3%, respectively. Although there are significant variations in EBL throughout the literature, it can be minimized by utilizing tranexamic acid intraoperatively. The ability to correct a rigid deformity in the spine relies on osteotomies. Each osteotomy is associated with a particular magnitude of correction at a single level. Posterior vertebral column resection is the most powerful posterior osteotomy method providing a successful correction of fixed complex deformities. Despite meticulous surgical technique and precision, this robust osteotomy technique can be associated with significant morbidity even in the most experienced hands.

  8. Effect of backmixing on pulse column performance

    International Nuclear Information System (INIS)

    Miao, Y.W.

    1979-05-01

    A critical survey of the published literature concerning dispersed phase holdup and longitudinal mixing in pulsed sieve-plate extraction columns has been made to assess the present state-of-the-art in predicting these two parameters, both of which are of critical importance in the development of an accurate mathematical model of the pulse column. Although there are many conflicting correlations of these variables as a function of column geometry, operating conditions, and physical properties of the liquid systems involved it has been possible to develop new correlations which appear to be useful and which are consistent with much of the available data over the limited range of variables most likely to be encountered in plant sized equipment. The correlations developed were used in a stagewise model of the pulse column to predict product concentrations, solute inventory, and concentration profiles in a column for which limited experimental data were available. Reasonable agreement was obtained between the mathematical model and the experimental data. Complete agreement, however, can only be obtained after a correlation for the extraction efficiency has been developed. The correlation of extraction efficiency was beyond the scope of this work

  9. Estimation of Chromatographic Columns Performances using Computer Tomography and CFD Simulations

    DEFF Research Database (Denmark)

    Schmidt, Irma; Lottes, Florian; Minceva, Mirjana

    2011-01-01

    The flow inside a chromatographic column depends decisively on the packed bed inside. Non‐destructive X‐ray computed tomography (CT) was applied as a novel measurement technique to visualize the distribution of velocity and axial dispersion coefficients in preparative scale columns. The results...... show, that spherical particles seem to be more efficient than irregular ones in terms of HETP, which has to be partly a result of the more homogeneous flow profile they induce. The prediction of column performance in dependence of the structure of the packed bed was simulated by CFD (Computational...

  10. Column Grid Array Rework for High Reliability

    Science.gov (United States)

    Mehta, Atul C.; Bodie, Charles C.

    2008-01-01

    Due to requirements for reduced size and weight, use of grid array packages in space applications has become common place. To meet the requirement of high reliability and high number of I/Os, ceramic column grid array packages (CCGA) were selected for major electronic components used in next MARS Rover mission (specifically high density Field Programmable Gate Arrays). ABSTRACT The probability of removal and replacement of these devices on the actual flight printed wiring board assemblies is deemed to be very high because of last minute discoveries in final test which will dictate changes in the firmware. The questions and challenges presented to the manufacturing organizations engaged in the production of high reliability electronic assemblies are, Is the reliability of the PWBA adversely affected by rework (removal and replacement) of the CGA package? and How many times can we rework the same board without destroying a pad or degrading the lifetime of the assembly? To answer these questions, the most complex printed wiring board assembly used by the project was chosen to be used as the test vehicle, the PWB was modified to provide a daisy chain pattern, and a number of bare PWB s were acquired to this modified design. Non-functional 624 pin CGA packages with internal daisy chained matching the pattern on the PWB were procured. The combination of the modified PWB and the daisy chained packages enables continuity measurements of every soldered contact during subsequent testing and thermal cycling. Several test vehicles boards were assembled, reworked and then thermal cycled to assess the reliability of the solder joints and board material including pads and traces near the CGA. The details of rework process and results of thermal cycling are presented in this paper.

  11. Mathematical modeling of alcohol distillation columns

    Directory of Open Access Journals (Sweden)

    Ones Osney Pérez

    2011-04-01

    Full Text Available New evaluation modules are proposed to extend the scope of a modular simulator oriented to the sugar cane industry, called STA 4.0, in a way that it can be used to carry out x calculation and analysis in ethanol distilleries. Calculation modules were developed for the simulation of the columns that are combined in the distillation area. Mathematical models were supported on materials and energy balances, equilibrium relations and thermodynamic properties of the ethanol-water system. Ponchon-Savarit method was used for the evaluation of the theoretical stages in the columns. A comparison between the results using Ponchon- Savarit method and those obtained applying McCabe-Thiele method was done for a distillation column. These calculation modules for ethanol distilleries were applied to a real case for validation.

  12. Inert carriers for column extraction chromatography

    International Nuclear Information System (INIS)

    Katykhin, G.S.

    1978-01-01

    Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al 2 O 3 ) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

  13. CUB DI (Deionization) column control system

    International Nuclear Information System (INIS)

    Seino, K.C.

    1999-01-01

    For the old MR (Main Ring), deionization was done with two columns in CUB, using an ion exchange process. Typically 65 GPM of LCW flew through a column, and the resistivity was raised from 3 Mohm-cm to over 12 Mohm-cm. After a few weeks, columns lost their effectiveness and had to be regenerated in a process involving backwashing and adding hydrochloric acid and sodium hydroxide. For normal MR operations, LCW returned from the ring and passed through the two columns in parallel for deionization, although the system could have been operated satisfactorily with only one in use. A 3000 gallon reservoir (the Spheres) provided a reserve of LCW for allowing water leaks and expansions in the MR. During the MI (Main Injector) construction period, the third DI column was added to satisfy requirements for the MI. When the third column was added, the old regeneration controller was replaced with a new controller based on an Allen-Bradley PLC (i.e., SLC-5/04). The PLC is widely used and well documented, and therefore it may allow us to modify the regeneration programs in the future. In addition to the above regeneration controller, the old control panels (which were used to manipulate pumps and valves to supply LCW in Normal mode and to do Int. Recir. (Internal Recirculation) and Makeup) were replaced with a new control system based on Sixtrak Gateway and I/O modules. For simplicity, the new regeneration controller is called as the US Filter system, and the new control system is called as the Fermilab system in this writing

  14. Operation of the annular pulsed column, (2)

    International Nuclear Information System (INIS)

    Takahashi, Keiki; Tsukada, Takeshi

    1988-01-01

    The heat of reaction generated form the uranium extraction is considered to from the temperature profile inside the pulsed column. A simulation code was developed to estimate the temperature profile, considering heat generation and counter-current heat transfer. The temperature profiles calculated using this code was found to depend on both the position of the extraction zone and the operating condition. The reported experimental result was fairly represented by this simulation code. We consider that this presented simulation code is capable of providing with the temperature profile in the pulsed column and useful for the monitoring of the uranium extraction zone. (author)

  15. Distillation columns inspection through gamma scanning

    International Nuclear Information System (INIS)

    Garcia, Marco

    1999-09-01

    The application of nuclear energy is very wide and it allows the saving of economic resources since the investigation of a certain process is carried out without stop the plant. The gamma scanning of oil c racking c olumns are practical examples, they allow to determine the hydraulic operation of the inspected columns. A source of Co-60 22mCi and a detector with a crystal of INa(TI) are used. This paper shows the results got from a profile carried out in a column distillation

  16. Performance of RC columns with partial length corrosion

    International Nuclear Information System (INIS)

    Wang Xiaohui; Liang Fayun

    2008-01-01

    Experimental and analytical studies on the load capacity of reinforced concrete (RC) columns with partial length corrosion are presented, where only a fraction of the column length was corroded. Twelve simply supported columns were eccentrically loaded. The primary variables were partial length corrosion in tensile or compressive zone and the corrosion level within this length. The failure of the corroded column occurs in the partial length, mainly developed from or located nearby or merged with the longitudinal corrosion cracks. For RC column with large eccentricity, load capacity of the column is mainly influenced by the partial length corrosion in tensile zone; while for RC column with small eccentricity, load capacity of the column greatly decreases due to the partial length corrosion in compressive zone. The destruction of the longitudinally mechanical integrality of the column in the partial length leads to this great reduction of the load capacity of the RC column

  17. Built for speed: strain in the cartilaginous vertebral columns of sharks.

    Science.gov (United States)

    Porter, M E; Diaz, Candido; Sturm, Joshua J; Grotmol, Sindre; Summers, A P; Long, John H

    2014-02-01

    In most bony fishes vertebral column strain during locomotion is almost exclusively in the intervertebral joints, and when these joints move there is the potential to store and release strain energy. Since cartilaginous fishes have poorly mineralized vertebral centra, we tested whether the vertebral bodies undergo substantial strain and thus may be sites of energy storage during locomotion. We measured axial strains of the intervertebral joints and vertebrae in vivo and ex vivo to characterize the dynamic behavior of the vertebral column. We used sonomicrometry to directly measure in vivo and in situ strains of intervertebral joints and vertebrae of Squalus acanthias swimming in a flume. For ex vivo measurements, we used a materials testing system to dynamically bend segments of vertebral column at frequencies ranging from 0.25 to 1.00 Hz and a range of physiologically relevant curvatures, which were determined using a kinematic analysis. The vertebral centra of S. acanthias undergo strain during in vivo volitional movements as well as in situ passive movements. Moreover, when isolated segments of vertebral column were tested during mechanical bending, we measured the same magnitudes of strain. These data support our hypothesis that vertebral column strain in lateral bending is not limited to the intervertebral joints. In histological sections, we found that the vertebral column of S. acanthias has an intracentral canal that is open and covered with a velum layer. An open intracentral canal may indicate that the centra are acting as tunics around some sections of a hydrostat, effectively stiffening the vertebral column. These data suggest that the entire vertebral column of sharks, both joints and centra, is mechanically engaged as a dynamic spring during locomotion. Copyright © 2013 Elsevier GmbH. All rights reserved.

  18. Two-fluid model LES of a bubble column

    International Nuclear Information System (INIS)

    Brahma N Reddy Vanga; Martin A Lopez de Bertodano; Eckhard Krepper; Alexandr Zaruba; Horst-Michael Prasser

    2005-01-01

    The hydrodynamics of a rectangular bubble column operating in the dispersed bubbly regime has been numerically investigated using a two-fluid model Large Eddy Simulation (LES). Experimental data were obtained to validate the model. LES computational fluid dynamic calculations of the transient flow for the bubble column were performed to account for the turbulence in the liquid phase. The computational mesh is of the same scale as the bubble size. The sub grid-scale Reynolds stresses were calculated with the Smagorinsky model. Furthermore, the effect of the bubbles on the turbulence in the continuous phase was modeled using Sato's eddy viscosity model for bubble-induced turbulence. Mean quantities were computed by averaging over a time period that was longer than the dynamic time scales of the turbulence, in particular the void fraction and the average velocity of the bubbles. A systematic analysis of the effect of the interfacial momentum transfer terms on these quantities has been conducted. The bubble column was locally aerated using a sparger located in the center of the bottom plate. The experimental studies involve wire-mesh tomography measurements for void fraction and bubble size distributions and digital image processing of high speed camera images for estimation of bubble velocities, size distributions and flow patterns. Experiments were performed for various aspect ratios (height of water column to width ratio) and superficial gas velocities. It was found that the non-drag bubble forces play a very prominent role in the predicting the correct flow pattern and void fraction distributions. In the calculations, the lift force and the wall force were considered. A 'wall peak' in the time averaged void fraction distribution has been experimentally observed and this cannot be predicted without including these non-drag forces in the numerical calculations. In this paper, experimental data are compared with the results of the numerical simulations. (authors)

  19. Scalability of pre-packed preparative chromatography columns with different diameters and lengths taking into account extra column effects.

    Science.gov (United States)

    Schweiger, Susanne; Jungbauer, Alois

    2018-02-16

    Small pre-packed columns are commonly used to estimate the optimum run parameters for pilot and production scale. The question arises if the experiments obtained with these columns are scalable, because there are substantial changes in extra column volume when going from a very small scale to a benchtop column. In this study we demonstrate the scalability of pre-packed disposable and non-disposable columns of volumes in the range of 0.2-20 ml packed with various media using superficial velocities in the range of 30-500 cm/h. We found that the relative contribution of extra column band broadening to total band broadening was not only high for columns with small diameters, but also for columns with a larger volume due to their wider diameter. The extra column band broadening can be more than 50% for columns with volumes larger than 10 ml. An increase in column diameter leads to high additional extra column band broadening in the filter, frits, and adapters of the columns. We found a linear relationship between intra column band broadening and column length, which increased stepwise with increases in column diameter. This effect was also corroborated by CFD simulation. The intra column band broadening was the same for columns packed with different media. An empirical engineering equation and the data gained from the extra column effects allowed us to predict the intra, extra, and total column band broadening just from column length, diameter, and flow rate. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  20. Convolutional Codes with Maximum Column Sum Rank for Network Streaming

    OpenAIRE

    Mahmood, Rafid; Badr, Ahmed; Khisti, Ashish

    2015-01-01

    The column Hamming distance of a convolutional code determines the error correction capability when streaming over a class of packet erasure channels. We introduce a metric known as the column sum rank, that parallels column Hamming distance when streaming over a network with link failures. We prove rank analogues of several known column Hamming distance properties and introduce a new family of convolutional codes that maximize the column sum rank up to the code memory. Our construction invol...

  1. Design and Operation of Cryogenic Distillation Research Column for Ultra-Low Background Experiments

    Science.gov (United States)

    Chiller, Christopher; Alanson Chiller, Angela; Jasinski, Benjamin; Snyder, Nathan; Mei, Dongming

    2013-04-01

    Motivated by isotopically enriched germanium (76Ge and 73Ge) for monocrystalline crystal growth for neutrinoless double-beta decay and dark matter experiments, a cryogenic distillation research column was developed. Without market availability of distillation columns in the temperature range of interest with capabilities necessary for our purposes, we designed, fabricated, tested, refined and operated a two-meter research column for purifying and separating gases in the temperature range from 100-200K. Due to interest in defining stratification, purity and throughput optimization, capillary lines were integrated at four equidistant points along the length of the column such that real-time residual gas analysis could guide the investigation. Interior gas column temperatures were monitored and controlled within 0.1oK accuracy at the top and bottom. Pressures were monitored at the top of the column to four significant figures. Subsequent impurities were measured at partial pressures below 2E-8torr. We report the performance of the column in this paper.

  2. High-field fMRI unveils orientation columns in humans.

    Science.gov (United States)

    Yacoub, Essa; Harel, Noam; Ugurbil, Kâmil

    2008-07-29

    Functional (f)MRI has revolutionized the field of human brain research. fMRI can noninvasively map the spatial architecture of brain function via localized increases in blood flow after sensory or cognitive stimulation. Recent advances in fMRI have led to enhanced sensitivity and spatial accuracy of the measured signals, indicating the possibility of detecting small neuronal ensembles that constitute fundamental computational units in the brain, such as cortical columns. Orientation columns in visual cortex are perhaps the best known example of such a functional organization in the brain. They cannot be discerned via anatomical characteristics, as with ocular dominance columns. Instead, the elucidation of their organization requires functional imaging methods. However, because of insufficient sensitivity, spatial accuracy, and image resolution of the available mapping techniques, thus far, they have not been detected in humans. Here, we demonstrate, by using high-field (7-T) fMRI, the existence and spatial features of orientation- selective columns in humans. Striking similarities were found with the known spatial features of these columns in monkeys. In addition, we found that a larger number of orientation columns are devoted to processing orientations around 90 degrees (vertical stimuli with horizontal motion), whereas relatively similar fMRI signal changes were observed across any given active column. With the current proliferation of high-field MRI systems and constant evolution of fMRI techniques, this study heralds the exciting prospect of exploring unmapped and/or unknown columnar level functional organizations in the human brain.

  3. Development of an Airborne Triple-Pulse 2-Micron Integrated Path Differential Absorption Lidar (IPDA) for Simultaneous Airborne Column Measurements of Carbon Dioxide and Water Vapor in the Atmosphere

    Science.gov (United States)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong; Antill, Charles W.; Remus, Ruben

    2016-01-01

    This presentation will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar being developed at NASA Langley Research Center with support from NASA ESTO Instrument Incubator Program. The development of this active optical remote sensing IPDA instrument is targeted for measuring both atmospheric carbon dioxide and water vapor in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver and detector upgrades, laser packaging and lidar integration. Future plan for IPDA lidar system for ground integration, testing and flight validation will also be presented.

  4. Pulsing flow in trickle bed columns

    NARCIS (Netherlands)

    Blok, Jan Rudolf

    1981-01-01

    In the operation of a packed column with cocurrent downflow of gas and liquid (trickle bed) several flowpatterns can be observed depending on the degree of interaction between gas and liquid. At low liquid and gas flow rates - low interaction - gascontinuous flow occurs. In this flowregime, the

  5. Revive your columns with cyclic distillation

    NARCIS (Netherlands)

    Kiss, Anton A.; Bîldea, Costin Sorin

    2015-01-01

    The process intensification (PI) technique involves changing a tower?s internals and operating mode and the separate movement of the liquid and vapor phases. This can significantly increase column throughput and reduce energy requirements, while improving separation performance. PI is a set of

  6. Robust Geometric Control of a Distillation Column

    DEFF Research Database (Denmark)

    Kymmel, Mogens; Andersen, Henrik Weisberg

    1987-01-01

    A frequency domain method, which makes it possible to adjust multivariable controllers with respect to both nominal performance and robustness, is presented. The basic idea in the approach is that the designer assigns objectives such as steady-state tracking, maximum resonance peaks, bandwidth, m...... is used to examine and improve geometric control of a binary distillation column....

  7. On Row Rank Equal Column Rank

    Science.gov (United States)

    Khalili, Parviz

    2009-01-01

    We will prove a well-known theorem in Linear Algebra, that is, for any "m x n" matrix the dimension of row space and column space are the same. The proof is based on the subject of "elementary matrices" and "reduced row-echelon" form of a matrix.

  8. On Stability of a Bubble Column

    Czech Academy of Sciences Publication Activity Database

    Růžička, Marek

    2013-01-01

    Roč. 91, č. 2 (2013), s. 191-203 ISSN 0263-8762 R&D Projects: GA ČR GA104/07/1110 Institutional support: RVO:67985858 Keywords : bubble column * flow regimes * steady solution Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.281, year: 2013

  9. Thermal Analysis of LANL Ion Exchange Column

    International Nuclear Information System (INIS)

    Laurinat, J.E.

    1999-01-01

    This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades

  10. Column Stores as an IR Prototyping Tool

    NARCIS (Netherlands)

    H.F. Mühleisen (Hannes); T. Samar (Thaer); J.J.P. Lin (Jimmy); A.P. de Vries (Arjen)

    2014-01-01

    textabstract. We make the suggestion that instead of implementing custom index structures and query evaluation algorithms, IR researchers should simply store document representations in a column-oriented relational database and write ranking models using SQL. For rapid prototyping, this is

  11. The Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI: design, execution, and early results

    Directory of Open Access Journals (Sweden)

    A. J. M. Piters

    2012-02-01

    Full Text Available From June to July 2009 more than thirty different in-situ and remote sensing instruments from all over the world participated in the Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI. The campaign took place at KNMI's Cabauw Experimental Site for Atmospheric Research (CESAR in the Netherlands. Its main objectives were to determine the accuracy of state-of-the-art ground-based measurement techniques for the detection of atmospheric nitrogen dioxide (both in-situ and remote sensing, and to investigate their usability in satellite data validation. The expected outcomes are recommendations regarding the operation and calibration of such instruments, retrieval settings, and observation strategies for the use in ground-based networks for air quality monitoring and satellite data validation. Twenty-four optical spectrometers participated in the campaign, of which twenty-one had the capability to scan different elevation angles consecutively, the so-called Multi-axis DOAS systems, thereby collecting vertical profile information, in particular for nitrogen dioxide and aerosol. Various in-situ samplers and lidar instruments simultaneously characterized the variability of atmospheric trace gases and the physical properties of aerosol particles. A large data set of continuous measurements of these atmospheric constituents has been collected under various meteorological conditions and air pollution levels. Together with the permanent measurement capability at the CESAR site characterizing the meteorological state of the atmosphere, the CINDI campaign provided a comprehensive observational data set of atmospheric constituents in a highly polluted region of the world during summertime. First detailed comparisons performed with the CINDI data show that slant column measurements of NO2, O4 and HCHO with MAX-DOAS agree within 5 to 15%, vertical profiles of NO2 derived from several independent

  12. Experimental study of the retention properties of a cyclo olefin polymer pillar array column in reversed-phase mode

    NARCIS (Netherlands)

    Illa, Xavi; de Malsche, Wim; Gardeniers, Johannes G.E.; Desmet, Gert; Romano-Rodriguez, Albert

    2010-01-01

    Experimental measurements to study the retention capacity and band broadening under retentive conditions using micromachined non-porous pillar array columns fabricated in cyclo olefin polymer are presented. In particular, three columns with different depths but with the same pillar structure have

  13. Characterization of wide-pore reversed-phase columns for biopolymer separations. I. Single-parametric evaluation

    NARCIS (Netherlands)

    Bede, A; Rippel, G; Szepesy, L; Claessens, H.A.

    1996-01-01

    Nine prepacked wide-pore columns recommended for protein separation were studied. The stationary phases investigated were widely different with respect to the type of ligands. In order to characterize the columns, measurements were made with six different test mixtures containing two different

  14. PHOTOGRAMMETRIC APPROACH IN DETERMINING BEAM-COLUMN CONNECTION DEFORMATIONS

    Directory of Open Access Journals (Sweden)

    Ali Koken

    Full Text Available In accordance with the advances in technology, displacement calculation techniques are ever developing. Photogrammetry has become preferable in some new disciplines with the advances in the image processing methods. In this study, the authors have used two different measurement techniques to determine the angles of rotation in beam-column connections that are subjected to reversible cyclic loading. The first of these is the method that is widely used, the conventional method in structural mechanics experiments, where Linear Variable Differential Transformers (LVDTs are utilized; and the second is the photogrammetric measurement technique. The rotation angles were determined using these techniques in a total of ten steel beam-column connection experiments. After discussing the test procedures of the aforementioned methods, the results were presented. It was observed that the rotation angles measured by each method were very close to each other. It was concluded that the photogrammetric measurement technique could be used as an alternative to conventional methods, where electronic LVDTs are used.

  15. The role of sidestream recycle in hydrogen isotope separation and column cascade design

    International Nuclear Information System (INIS)

    Sherman, R.H.; Taylor, D.J.; Yamanishi, T.; Enoeda, M.; Konishi, S.; Okuno, K.

    1994-01-01

    Sidestream recycle combined with sidestream equilibration is important in hydrogen isotopic distillation processes because it offers a means to reduce the number of columns required for the extraction of pure homonuclear species. This directly implies simpler systems, reduced control problems, and reduce material inventories. Measurements were recently completed for a single distillation column using feed compositions (∼50--50 D-T) and product flows similar to those expected in an ITER type device wit recycle of an equilibrated sidestream withdrawn from the column. Dynamic studies were conducted with flowrates changing as might be expected for typical Tokamak operations. These experimental results are compared with computer simulations of the dynamic process. The impact of these sidestream recycle studies on the design of isotope separation systems is discussed, especially with respect to column design, tritium inventory, dynamic performance, stability, and system control

  16. Water column velocimeter for NSRR experiment. Characteristics and data processing procedure

    International Nuclear Information System (INIS)

    Sugiyama, Tomoyuki; Fuketa, Toyoshi

    2000-11-01

    In order to clarify fuel behavior under reactivity initiated accident (RIA) conditions, pulse irradiation experiments on fuel rods are carried out in the Nuclear Safety Research Reactor (NSRR). One of concerns at fuel failure is mechanical energy generation in the reactor vessel. The mechanical energy is generated by a water hammer or a pressure impact occurred at fuel failure, and has possibility to damage reactor structures. Thus, the amount of generated mechanical energy is critical information for the safety evaluation of power reactor. In the NSRR experiments, the mechanical energy due to the water hammer is evaluated as the kinetic energy of the jumping water column at fuel failure, and the velocity of the water column is measured by the float type water column velocimeter. This report presents characteristics of the water column velocimeter and the procedure of data processing in the NSRR experiments. (author)

  17. Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

    Science.gov (United States)

    Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

    2017-11-01

    Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Ultra high pressure liquid chromatography. Column permeability and changes of the eluent properties.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2008-04-11

    The behavior of four similar liquid chromatography columns (2.1mm i.d. x 30, 50, 100, and 150 mm, all packed with fine particles, average d(p) approximately 1.7 microm, of bridged ethylsiloxane/silica hybrid-C(18), named BEH-C(18)) was studied in wide ranges of temperature and pressure. The pressure and the temperature dependencies of the viscosity and the density of the eluent (pure acetonitrile) along the columns were also derived, using the column permeabilities and applying the Kozeny-Carman and the heat balance equations. The heat lost through the external surface area of the chromatographic column was directly derived from the wall temperature of the stainless steel tube measured with a precision of +/-0.2 degrees C in still air and +/-0.1 degrees C in the oven compartment. The variations of the density and viscosity of pure acetonitrile as a function of the temperature and pressure was derived from empirical correlations based on precise experimental data acquired between 298 and 373 K and at pressures up to 1.5 kbar. The measurements were made with the Acquity UPLC chromatograph that can deliver a maximum flow rate of 2 mL/min and apply a maximum column inlet pressure of 1038 bar. The average Kozeny-Carman permeability constant of the columns was 144+/-3.5%. The temperature hence the viscosity and the density profiles of the eluent along the column deviate significantly from linear behavior under high-pressure gradients. For a 1000 bar pressure drop, we measured DeltaT=25-30 K, (Deltaeta/eta) approximately 100%, and (Deltarho/rho) approximately 10%. These results show that the radial temperature profiles are never fully developed within 1% for any of the columns, even under still-air conditions. This represents a practical advantage regarding the apparent column efficiency at high flow rates, since the impact of the differential analyte velocity between the column center and the column wall is not maximum. The interpretation of the peak profiles recorded in

  19. Column, particularly extraction column, for fission and/or breeder materials

    International Nuclear Information System (INIS)

    Vietzke, H.; Pirk, H.

    1980-01-01

    An absorber rod with a B 4 C insert is situated in the long extraction column for a uranyl nitrate solution or a plutonium nitrate solution. The geometrical dimensions are designed for a high throughput with little corrosion. (DG) [de

  20. Flow rate dependent extra-column variance from injection in capillary liquid chromatography.

    Science.gov (United States)

    Aggarwal, Pankaj; Liu, Kun; Sharma, Sonika; Lawson, John S; Dennis Tolley, H; Lee, Milton L

    2015-02-06

    Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Study on Gas-liquid Falling Film Flow in Internal Heat Integrated Distillation Column

    Science.gov (United States)

    Liu, Chong

    2017-10-01

    Gas-liquid internally heat integrated distillation column falling film flow with nonlinear characteristics, study on gas liquid falling film flow regulation control law, can reduce emissions of the distillation column, and it can improve the quality of products. According to the distribution of gas-liquid mass balance internally heat integrated distillation column independent region, distribution model of heat transfer coefficient of building internal heat integrated distillation tower is obtained liquid distillation falling film flow in the saturated vapour pressure of liquid water balance, using heat transfer equation and energy equation to balance the relationship between the circulating iterative gas-liquid falling film flow area, flow parameter information, at a given temperature, pressure conditions, gas-liquid flow falling film theory makes the optimal parameters to achieve the best fitting value with the measured values. The results show that the geometric gas-liquid internally heat integrated distillation column falling film flow heat exchange area and import column thermostat, the average temperature has significant. The positive correlation between the heat exchanger tube entrance due to temperature difference between inside and outside, the heat flux is larger, with the increase of internal heat integrated distillation column temperature, the slope decreases its temperature rise, which accurately describes the internal gas-liquid heat integrated distillation tower falling film flow regularity, take appropriate measures to promote the enhancement of heat transfer. It can enhance the overall efficiency of the heat exchanger.

  2. Establishing column batch repeatability according to Quality by Design (QbD) principles using modeling software.

    Science.gov (United States)

    Rácz, Norbert; Kormány, Róbert; Fekete, Jenő; Molnár, Imre

    2015-04-10

    Column technology needs further improvement even today. To get information of batch-to-batch repeatability, intelligent modeling software was applied. Twelve columns from the same production process, but from different batches were compared in this work. In this paper, the retention parameters of these columns with real life sample solutes were studied. The following parameters were selected for measurements: gradient time, temperature and pH. Based on calculated results, batch-to-batch repeatability of BEH columns was evaluated. Two parallel measurements on two columns from the same batch were performed to obtain information about the quality of packing. Calculating the average of individual working points at the highest critical resolution (R(s,crit)) it was found that the robustness, calculated with a newly released robustness module, had a success rate >98% among the predicted 3(6) = 729 experiments for all 12 columns. With the help of retention modeling all substances could be separated independently from the batch and/or packing, using the same conditions, having high robustness of the experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. HETP evaluation of structured packing distillation column

    Directory of Open Access Journals (Sweden)

    A. E. Orlando Jr.

    2009-09-01

    Full Text Available Several tests with a hydrocarbon mixture of known composition (C8-C14, obtained from DETEN Chemistry S.A., have been performed in a laboratory distillation column, having 40mm of nominal diameter and 2.2m high, with internals of Sulzer DX gauze stainless steel structured packing. The main purpose of this work was to evaluate HETP of a structured packing laboratory scale distillation column, operating continuously. Six HETP correlations available in the literature were compared in order to find out which is the most appropriate for structured packing columns working with medium distillates. Prior to the experimental tests, simulation studies using commercial software PRO/II® were performed in order to establish the optimum operational conditions for the distillation, especially concerning operating pressure, top and bottom temperatures, feed location and reflux ratio. The results of PRO/II® were very similar to the analysis of the products obtained during continuous operation, therefore permitting the use of the properties calculated by that software on the theoretical models investigated. The theoretical models chosen for HETP evaluation were: Bravo, Rocha and Fair (1985; Rocha, Bravo and Fair (1993, 1996; Brunazzi and Pagliant (1997; Carlo, Olujić and Pagliant (2006; Olujić et al., (2004. Modifications concerning calculation of specific areas were performed on the correlations in order to fit them for gauze packing HETP evaluation. As the laboratory distillation column was operated continuously, different HETP values were found by the models investigated for each section of the column. The low liquid flow rates in the top section of the column are a source of error for HETP evaluation by the models; therefore, more reliable HETP values were found in the bottom section, in which liquid flow rates were much greater. Among the theoretical models, Olujić et al. (2004 has shown good results relative to the experimental tests. In addition, the

  4. Mitigating oil spills in the water column

    International Nuclear Information System (INIS)

    Barry, Edward; Libera, Joseph A.; Mane, Anil University; Avila, Jason R.; DeVitis, David

    2017-01-01

    The scale and scope of uncontrolled oil spills can be devastating. Diverse marine environments and fragile ecologies are some of the most susceptible to the many ill effects, while the economic costs can be crippling. A notoriously difficult challenge with no known technological solution is the successful removal of oil dispersed in the water column. Here, we address this problem through cheap and reusable oil sorbents based on the chemical modification of polymer foams. Interfacial chemistry was optimized and subsequently tested in a simulated marine environment at the National Oil Spill Response Research & Renewable Energy Test Facility, Ohmsett. We find favorable performance for surface oil mitigation and, for the first time, demonstrate the advanced sorbent's efficiency and efficacy at pilot scale in extraction of crude oil and refined petroleum products dispersed in the water column. As a result, this is a potentially disruptive technology, opening a new field of environmental science focused on sub-surface pollutant sequestration.

  5. Assembly procedure for column cutting platform

    International Nuclear Information System (INIS)

    Routh, R.D.

    1995-01-01

    This supporting document describes the assembly procedure for the Column Cutting Platform and Elevation Support. The Column Cutting Platform is a component of the 241-SY-101 Equipment Removal System. It is set up on the deck of the Strongback Trailer to provide work access to cut off the upper portion of the Mitigation Pump Assembly (MPA). The Elevation Support provides support for the front of the Storage Container with the Strongback at an inclined position. The upper portion of the MPA must be cut off to install the Containment Caps on the Storage Container. The storage Container must be maintained in an inclined position until the Containment Caps are installed to prevent any residual liquids from migrating forward in the Storage Container

  6. Modeling of Crystalline Silicotitanate Ion Exchange Columns

    International Nuclear Information System (INIS)

    Walker, D.D.

    1999-01-01

    Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R. G. Anthony, Department of Chemical Engineering, Texas A ampersand 038;M University, and Professor S. W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports

  7. Optimization of the isotope separation in columns

    International Nuclear Information System (INIS)

    Kaminskij, V.A.; Vetsko, V.M.; Tevzadze, G.A.; Devdariani, O.A.; Sulaberidze, G.A.

    1982-01-01

    The general method for the multi-parameter optimization of cascade plants of packed columns is proposed. As an optimization effectiveness function a netcost of the isotopic product is selected. The net cost is comprehensively characterizing the sum total of capital costs for manufacturing the products as well as determining the choice of the most effective directions for capital investments and rational limits of improvement of the products quality. The method is based on main representations of the cascade theory, such as the ideal flow profile and form efficiency as well as mathematical model of the packed column specifying the bonds between its geometric and operating parameters. As a result, the isotopic products cost function could be bound with such parameters as the equilibrium stage height, ultimate packing capacity, its element dimensions, column diameter. It is concluded that the suggested approach to the optimization of isotope separation processes is rather a general one. It permits to solve a number of special problems, such as estimation of advisability of using heat-pump circuits and determining the rational automation level. Besides, by means of the method suggested one can optimize the process conditions with regard to temperature and pressure

  8. Employing anatomical knowledge in vertebral column labeling

    Science.gov (United States)

    Yao, Jianhua; Summers, Ronald M.

    2009-02-01

    The spinal column constitutes the central axis of human torso and is often used by radiologists to reference the location of organs in the chest and abdomen. However, visually identifying and labeling vertebrae is not trivial and can be timeconsuming. This paper presents an approach to automatically label vertebrae based on two pieces of anatomical knowledge: one vertebra has at most two attached ribs, and ribs are attached only to thoracic vertebrae. The spinal column is first extracted by a hybrid method using the watershed algorithm, directed acyclic graph search and a four-part vertebra model. Then curved reformations in sagittal and coronal directions are computed and aggregated intensity profiles along the spinal cord are analyzed to partition the spinal column into vertebrae. After that, candidates for rib bones are detected using features such as location, orientation, shape, size and density. Then a correspondence matrix is established to match ribs and vertebrae. The last vertebra (from thoracic to lumbar) with attached ribs is identified and labeled as T12. The rest of vertebrae are labeled accordingly. The method was tested on 50 CT scans and successfully labeled 48 of them. The two failed cases were mainly due to rudimentary ribs.

  9. Local buckling of composite channel columns

    Science.gov (United States)

    Szymczak, Czesław; Kujawa, Marcin

    2018-05-01

    The investigation concerns local buckling of compressed flanges of axially compressed composite channel columns. Cooperation of the member flange and web is taken into account here. The buckling mode of the member flange is defined by rotation angle a flange about the line of its connection with the web. The channel column under investigation is made of unidirectional fibre-reinforced laminate. Two approaches to member orthotropic material modelling are performed: the homogenization with the aid of theory of mixture and periodicity cell or homogenization upon the Voigt-Reuss hypothesis. The fundamental differential equation of local buckling is derived with the aid of the stationary total potential energy principle. The critical buckling stress corresponding to a number of buckling half-waves is assumed to be a minimum eigenvalue of the equation. Some numerical examples dealing with columns are given here. The analytical results are compared with the finite element stability analysis carried out by means of ABAQUS software. The paper is focused on a close analytical solution of the critical buckling stress and the associated buckling mode while the web-flange cooperation is assumed.

  10. Quantitative analysis of SCIAMACHY carbon monoxide total column measurements

    NARCIS (Netherlands)

    Laat, de A.T.J.; Gloudemans, A.M.S.; Schrijver, H.; Broek, van den M.M.P.; Meirink, J.F.; Aben, I.; Krol, M.C.

    2006-01-01

    Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions

  11. A Comparative Field Monitoring of Column Shortenings in Tall Buildings Using Wireless and Wired Sensor Network Systems

    Directory of Open Access Journals (Sweden)

    Sungho Lee

    2016-01-01

    Full Text Available A comparative field measurement for column shortening of tall buildings is presented in this study, with a focus on the reliability and stability of a wireless sensor network. A wireless sensor network was used for monitoring the column shortenings of a 58-story building under construction. The wireless sensor network, which was composed of sensor and master nodes, employed the ultra-high-frequency band and CDMA communication methods. To evaluate the reliability and stability of the wireless sensor network system, the column shortenings were also measured using a conventional wired monitoring system. Two vibration wire gauges were installed in each of the selected 7 columns and 3 walls. Measurements for selected columns and walls were collected for 270 days after casting of the concrete. The results measured by the wireless sensor network were compared with the results of the conventional method. The strains and column shortenings measured using both methods showed good agreement for all members. It was verified that the column shortenings of tall buildings could be monitored using the wireless sensor network system with its reliability and stability.

  12. Adiabatic packed column supercritical fluid chromatography using a dual-zone still-air column heater.

    Science.gov (United States)

    Helmueller, Shawn C; Poe, Donald P; Kaczmarski, Krzysztof

    2018-02-02

    An approach to conducting SFC separations under pseudo-adiabatic condition utilizing a dual-zone column heater is described. The heater allows for efficient separations at low pressures above the critical temperature by imposing a temperature profile along the column wall that closely matches that for isenthalpic expansion of the fluid inside the column. As a result, the efficiency loss associated with the formation of radial temperature gradients in this difficult region can be largely avoided in packed analytical scale columns. For elution of n-octadecylbenzene at 60 °C with 5% methanol modifier and a flow rate of 3 mL/min, a 250 × 4.6-mm column packed with 5-micron Kinetex C18 particles began to lose efficiency (8% decrease in the number of theoretical plates) at outlet pressures below 142 bar in a traditional forced air oven. The corresponding outlet pressure for onset of excess efficiency loss was decreased to 121 bar when the column was operated in a commercial HPLC column heater, and to 104 bar in the new dual-zone heater operated in adiabatic mode, with corresponding increases in the retention factor for n-octadecylbenzene from 2.9 to 6.8 and 14, respectively. This approach allows for increased retention and efficient separations of otherwise weakly retained analytes. Applications are described for rapid SFC separation of an alkylbenzene mixture using a pressure ramp, and isobaric separation of a cannabinoid mixture. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Ultrasound-Guided Laryngeal Air Column Width Difference as a New Predictor for Postextubation Stridor in Children.

    Science.gov (United States)

    El Amrousy, Doaa; Elkashlan, Mohamed; Elshmaa, Nagat; Ragab, Ahmed

    2018-03-01

    To assess the efficacy of ultrasound-guided laryngeal air column width difference in predicting postextubation stridor in children. Prospective observational study. Single, tertiary care pediatric hospital. This study was carried out at PICU and surgical ICU, Tanta University Hospital on 400 ventilated children between January 2015 and May 2017. Patients who received mechanical ventilation and met criteria for a weaning trial were included. Laryngeal ultrasound and cuff leak test. Ultrasound-guided laryngeal air column width and cuff leak test were measured before extubation. Laryngeal air column width is the width of air between the vocal cords seen by laryngeal ultrasonography. Laryngeal air column width difference is the width difference of air column passed through vocal cords with the balloon cuff inflated and deflated. Three-hundred fifty six patients (89%) had no postextubation stridor, whereas 44 patients (11%) developed postextubation stridor. Postextubation stridor was associated with younger age, less weight, female gender, prolonged duration of intubation, and ICU stay (p column width difference and cuff leak test showed significant decrease (p column width difference at cutoff point of less than 0.8 mm gave a sensitivity of 93%, specificity of 86%, and accuracy of 91%, whereas cuff leak test at less than 11% yielded a sensitivity of (61%), specificity of (53%), and accuracy of (59%) for predicting postextubation stridor. Laryngeal air column width difference measurement may serve as a simple reliable noninvasive method for predicting postextubation stridor in children.

  14. Ductility of reinforced concrete columns confined with stapled strips

    International Nuclear Information System (INIS)

    Tahir, M.F.; Khan, Q.U.Z.; Shabbir, F.; Sharif, M.B.; Ijaz, N.

    2015-01-01

    Response of three 150x150x450mm short reinforced concrete (RC) columns confined with different types of confining steel was investigated. Standard stirrups, strips and stapled strips, each having same cross-sectional area, were employed as confining steel around four comer column bars. Experimental work was aimed at probing into the affect of stapled strip confinement on post elastic behavior and ductility level under cyclic axial load. Ductility ratios, strength enhancement factor and core concrete strengths were compared to study the affect of confinement. Results indicate that strength enhancement in RC columns due to strip and stapled strip confinement was not remarkable as compared to stirrup confined column. It was found that as compared to stirrup confined column, stapled strip confinement enhanced the ductility of RC column by 183% and observed axial capacity of stapled strip confined columns was 41 % higher than the strip confined columns. (author)

  15. EX0904 Water Column Summary Report and Profile Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A complete set of water column profile data and CTD Summary Report (if generated) generated by the Okeanos Explorer during EX0904: Water Column Exploration Field...

  16. Estimations of temperature deviations in chromatographic columns using isenthalpic plots. I. Theory for isocratic systems.

    Science.gov (United States)

    Tarafder, Abhijit; Iraneta, Pamela; Guiochon, Georges; Kaczmarski, Krzysztof; Poe, Donald P

    2014-10-31

    We propose to use constant enthalpy or isenthalpic diagrams as a tool to estimate the extent of the temperature variations caused by the mobile phase pressure drop along a chromatographic column, e.g. of its cooling in supercritical fluid and its heating in ultra-performance liquid chromatography. Temperature strongly affects chromatographic phenomena. Any of its variations inside the column, whether intended or not, can lead to significant changes in separation performance. Although instruments use column ovens in order to keep constant the column temperature, operating conditions leading to a high pressure drop may cause significant variations of the column temperature, both in the axial and the radial directions, from the set value. Different ways of measuring these temperature variations are available but they are too inconvenient to be employed in many practical situations. In contrast, the thermodynamic plot-based method that we describe here can easily be used with only a ruler and a pencil. They should be helpful in developing methods or in analyzing results in analytical laboratories. Although the most effective application area for this approach should be SFC (supercritical fluid chromatography), it can be applied to any chromatographic conditions in which temperature variations take place along the column due to the pressure drop, e.g. in ultra-high pressure liquid chromatography (UHPLC). The method proposed here is applicable to isocractic conditions only. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. A development of super computed tomography scanner for industrial column investigation

    International Nuclear Information System (INIS)

    Abdul Quddoos Abu Bakar; Jaafar Abdullah; Ismail Mustapha

    2004-01-01

    Computed Tomography (CT) scanner is a desired devices on create images of internal structure of unrecognized object. The formation of a CT images is a distinct three phase process. The scanning phase produces data, but not an image. Then, reconstruction phase processes the acquired data and forms a digital image. The visible and displayed analog image is produced by the digital to analog conversation phase. In this case, there are adjustable factors associated with each of these phases that can have an effect on the characteristics and quantity of the image. In term on this project of column scanning, during the scanning phase a fan-shaped gamma ray beam is scanned around the column. The amount of gamma radiation that penetrates the column along each individual ray (pathway) through the column is measured by the detectors that intercept the gamma ray beam after it passes through the column.This project of Super Computed Tomography (CT) is develop to reconstruct and redesign the mechanical parts and equipment to suits the purpose of the industrial column investigation in the region. (Author)

  18. The Two-Column Aerosol Project (TCAP) Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    Berkowitz, CM; Berg, LK; Cziczo, DJ; Flynn, CJ; Kassianov, EI; Fast, JD; Rasch, PJ; Shilling, JE; Zaveri, RA; Zelenyuk, A; Ferrare, RA; Hostetler, CA; Cairns, B; Russell, PB; Ervens, B

    2011-07-27

    The Two-Column Aerosol Project (TCAP) field campaign will provide a detailed set of observations with which to (1) perform radiative and cloud condensation nuclei (CCN) closure studies, (2) evaluate a new retrieval algorithm for aerosol optical depth (AOD) in the presence of clouds using passive remote sensing, (3) extend a previously developed technique to investigate aerosol indirect effects, and (4) evaluate the performance of a detailed regional-scale model and a more parameterized global-scale model in simulating particle activation and AOD associated with the aging of anthropogenic aerosols. To meet these science objectives, the Atmospheric Radiation Measurement (ARM) Climate Research Facility will deploy the ARM Mobile Facility (AMF) and the Mobile Aerosol Observing System (MAOS) on Cape Cod, Massachusetts, for a 12-month period starting in the summer of 2012 in order to quantify aerosol properties, radiation, and cloud characteristics at a location subject to both clear and cloudy conditions, and clean and polluted conditions. These observations will be supplemented by two aircraft intensive observation periods (IOPs), one in the summer and a second in the winter. Each IOP will deploy one, and possibly two, aircraft depending on available resources. The first aircraft will be equipped with a suite of in situ instrumentation to provide measurements of aerosol optical properties, particle composition and direct-beam irradiance. The second aircraft will fly directly over the first and use a multi-wavelength high spectral resolution lidar (HSRL) and scanning polarimeter to provide continuous optical and cloud properties in the column below.

  19. Cross flow cyclonic flotation column for coal and minerals beneficiation

    Science.gov (United States)

    Lai, Ralph W.; Patton, Robert A.

    2000-01-01

    An apparatus and process for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophillic tailings.

  20. Behaviour of FRP confined concrete in square columns

    OpenAIRE

    Diego Villalón, Ana de; Arteaga Iriarte, Ángel; Fernandez Gomez, Jaime Antonio; Perera Velamazán, Ricardo; Cisneros, Daniel

    2015-01-01

    A significant amount of research has been conducted on FRP-confined circular columns, but much less is known about rectangular/square columns in which the effectiveness of confinement is much reduced. This paper presents the results of experimental investigations on low strength square concrete columns confined with FRP. Axial compression tests were performed on ten intermediate size columns. The tests results indicate that FRP composites can significantly improve the bearing capacity and duc...

  1. Modalization in the Political Column of Tempo Magazine

    OpenAIRE

    Rahmah, Maria Betti Sinaga and

    2017-01-01

    The study focuses on analyzing the use of modalization in the Political Column of Tempo Magazine. The objectives were to find out the type of modalization and to describe the use of modalization in the Political Column of Tempo magazine. The data were taken from Political Column of Tempo magazine published in June and July 2017. The source of data was Political Column in Tempo magazine. The data analysis applied descriptive qualitative research. There were 135 clauses which contained Modaliza...

  2. Numerical Simulations of Settlement of Jet Grouting Columns

    Directory of Open Access Journals (Sweden)

    Juzwa Anna

    2016-03-01

    Full Text Available The paper presents the comparison of results of numerical analyses of interaction between group of jet grouting columns and subsoil. The analyses were conducted for single column and groups of three, seven and nine columns. The simulations are based on experimental research in real scale which were carried out by authors. The final goal for the research is an estimation of an influence of interaction between columns working in a group.

  3. Diffusive transport of radon in a homogeneous column of dry sand

    NARCIS (Netherlands)

    van der Spoel, W.H.; van der Graaf, E.R.; de Meijer, R.J.

    To validate a model for radon transport in soil, measurements of diffusive radon transport under well-defined and controlled conditions have been made in a homogeneous column of dry sand with an air-filled volume on top. This volume simulates a crawl space. The measurements concern time-dependent

  4. Aerosol Effects on Radiation and Climate: Column Closure Experiments with Towers, Aircraft, and Satellites

    Science.gov (United States)

    Russell, Philip B.

    1994-01-01

    Many theoretical studies have shown that anthropogenic aerosol particles can change the radiation balance in an atmospheric column and might thereby exert a significant effect on the Earth's climate. In particular, recent calculations have shown that sulfate particles from anthropogenic combustion may already exert a cooling influence on the Earth that partially offsets the warming caused by the greenhouse gases from the same combustion. Despite the potential climatic importance of anthropogenic aerosols, simultaneous measurements of anthropogenic aerosol properties and their effect on atmospheric radiation have been very rare. Successful comparisons of measured radiation fields with those calculated from aerosol measurements - now referred to as column closure comparisons - are required to improve the accuracy and credibility of climate predictions. This paper reviews the column closure experiment performed at the Mt. Sutro Tower in San Francisco in 1975, in which elevated radiometers measured the change in Earth-plus-atmosphere albedo caused by an aerosol layer, while a lidar, sunphotometer, nephelometer, and other radiometers measured properties of the responsible aerosol. The time-dependent albedo calculated from the measured aerosol properties agreed with that measured by the tower radiometers. Also presented are designs for future column closure studies using radiometers and aerosol instruments on the ground, aircraft, and satellites. These designs draw upon algorithms and experience developed in the Sutro Tower study, as well as more recent experience with current measurement and analysis capabilities.

  5. COMPUTATIONAL AND EXPERIMENTAL MODELING OF SLURRY BUBBLE COLUMN REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Paul C.K. Lam; Isaac K. Gamwo; Dimitri Gidaspow

    2002-05-01

    The objective of this study was to develop a predictive experimentally verified computational fluid dynamics (CFD) model for gas-liquid-solid flow. A three dimensional transient computer code for the coupled Navier-Stokes equations for each phase was developed and is appended in this report. The principal input into the model is the viscosity of the particulate phase which was determined from a measurement of the random kinetic energy of the 800 micron glass beads and a Brookfield viscometer. The details are presented in the attached paper titled ''CFD Simulation of Flow and Turbulence in a Slurry Bubble Column''. This phase of the work is in press in a referred journal (AIChE Journal, 2002) and was presented at the Fourth International Conference on Multiphase Flow (ICMF 2001) in New Orleans, May 27-June 1, 2001 (Paper No. 909). The computed time averaged particle velocities and concentrations agree with Particle Image Velocimetry (PIV) measurements of velocities and concentrations, obtained using a combination of gamma-ray and X-ray densitometers, in a slurry bubble column, operated in the bubbly-coalesced fluidization regime with continuous flow of water. Both the experiment and the simulation show a down-flow of particles in the center of the column and up-flow near the walls and nearly uniform particle concentration. Normal and shear Reynolds stresses were constructed from the computed instantaneous particle velocities. The PIV measurement and the simulation produced instantaneous particle velocities. The PIV measurement and the simulation produced similar nearly flat horizontal profiles of turbulent kinetic energy of particles. To better understand turbulence we studied fluidization in a liquid-solid bed. This work was also presented at the Fourth International Conference on Multiphase Flow (ICMF 2001, Paper No. 910). To understand turbulence in risers, measurements were done in the IIT riser with 530 micron glass beads using a PIV

  6. column frame for design of reinforced concrete sway frames

    African Journals Online (AJOL)

    adminstrator

    design of slender reinforced concrete columns in sway frames according .... concrete,. Ac = gross cross-sectional area of the columns. Step 3: Effective Buckling Length Factors. The effective buckling length factors of columns in a sway frame shall be computed by .... shall have adequate resistance to failure in a sway mode ...

  7. Behavior of reinforced concrete columns strenghtened by partial jacketing

    Directory of Open Access Journals (Sweden)

    D. B. FERREIRA

    Full Text Available This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column e PR (reference column. The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

  8. 46 CFR 174.085 - Flooding on column stabilized units.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Flooding on column stabilized units. 174.085 Section 174... Units § 174.085 Flooding on column stabilized units. (a) Watertight compartments that are outboard of... of the unit, must be assumed to be subject to flooding as follows: (1) When a column is subdivided...

  9. Water hammer with column separation : a historical review

    NARCIS (Netherlands)

    Bergant, A.; Simpson, A.R.; Tijsseling, A.S.

    2006-01-01

    Column separation refers to the breaking of liquid columns in fully filled pipelines. This may occur in a water-hammer event when the pressure in a pipeline drops to the vapor pressure at specific locations such as closed ends, high points or knees (changes in pipe slope). The liquid columns are

  10. Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments NAC/SETAC 2012

    Science.gov (United States)

    Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

  11. Relationship between surface, free tropospheric and total column ozone in 2 contrasting areas in South-Africa

    CSIR Research Space (South Africa)

    Combrink, J

    1995-04-01

    Full Text Available Measurements of surface ozone in two contrasting areas of South Africa are compared with free tropospheric and Total Ozone Mapping Spectrometer (TOMS) total column ozone data. Cape Point is representative of a background monitoring station which...

  12. Hydrodynamic Study Of Column Bioleaching Processes

    Directory of Open Access Journals (Sweden)

    Sadowski Zygmunt

    2015-06-01

    Full Text Available The modelling of flow leaching solution through the porous media has been considered. The heap bioleaching process can be tested using the column experimental equipment. This equipment was employed to the hydrodynamic studies of copper ore bioleaching. The copper ore (black shale ore with the support, inertial materials (glass small balls and polyethylene beads was used to the bioleaching tests. The packed beds were various composition, the ore/support ratio was changed. The correlation between the bed porosity and bioleaching kinetics, and copper recovery was investigated.

  13. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    The utilization of biomass combustion ashes for forest soil liming and fertilizing has been addressed in literature. Though, a deep understanding of the ash chemical composition and leaching behavior is necessary to predict potential benefits and environmental risks related to this practice....... In this study, a fly ash sample from an operating Danish power plant based on wood biomass was collected, chemically characterized and investigated for its leaching release of nutrients and heavy metals. A column leaching test was employed. The strongly alkaline pH of all the collected eluates suggested...

  14. Design of Steel Beam-Column Connections

    Directory of Open Access Journals (Sweden)

    Bogatinoski Z.

    2014-05-01

    Full Text Available In this paper a theoretical and experimental research of the steel beam-column connections is presented. Eight types of specimens were being researched, composed of rigid and semi-rigid connections from which 4 connections are with IPE - profile and 4 connections with tube's section for the beam. From the numerical analysis of the researched models, and especially from the experimental research at the Laboratory for Structures in the Faculty of Mechanical Engineering - Skopje, specific conclusions were received that ought to have theoretical and practical usage for researchers in this area of interest.

  15. Dynamic Deformation and Collapse of Granular Columns

    Science.gov (United States)

    Uenishi, K.; Tsuji, K.; Doi, S.

    2009-12-01

    Large dynamic deformation of granular materials may be found in nature not only in the failure of slopes and cliffs — due to earthquakes, rock avalanches, debris flows and landslides — but also in earthquake faulting itself. Granular surface flows often consist of solid grains and intergranular fluid, but the effect of the fluid may be usually negligible because the volumetric concentration of grains is in many cases high enough for interparticle forces to dominate momentum transport. Therefore, the investigation of dry granular flow of a mass might assist in further understanding of the above mentioned geophysical events. Here, utilizing a high-speed digital video camera system, we perform a simple yet fully-controlled series of laboratory experiments related to the collapse of granular columns. We record, at an interval of some microseconds, the dynamic transient granular mass flow initiated by abrupt release of a tube that contains dry granular materials. The acrylic tube is partially filled with glass beads and has a cross-section of either a fully- or semi-cylindrical shape. Upon sudden removal of the tube, the granular solid may fragment under the action of its own weight and the particles spread on a rigid horizontal plane. This study is essentially the extension of the previous ones by Lajeunesse et al. (Phys. Fluids 2004) and Uenishi and Tsuji (JPGU 2008), but the striped layers of particles in a semi-cylindrical tube, newly introduced in this contribution, allow us to observe the precise particle movement inside the granular column: The development of slip lines inside the column and the movement of particles against each other can be clearly identified. The major controlling parameters of the spreading dynamics are the initial aspect ratio of the granular (semi-)cylindrical column, the frictional properties of the horizontal plane (substrate) and the size of beads. We show the influence of each parameter on the average flow velocity and final radius

  16. A review of oscillating water columns.

    Science.gov (United States)

    Heath, T V

    2012-01-28

    This paper considers the history of oscillating water column (OWC) systems from whistling buoys to grid-connected power generation systems. The power conversion from the wave resource through to electricity via pneumatic and shaft power is discussed in general terms and with specific reference to Voith Hydro Wavegen's land installed marine energy transformer (LIMPET) plant on the Scottish island of Islay and OWC breakwater systems. A report on the progress of other OWC systems and power take-off units under commercial development is given, and the particular challenges faced by OWC developers reviewed.

  17. Preinjector for Linac 1, accelerating column

    CERN Multimedia

    1974-01-01

    For a description of the Linac 1 preinjector, please see first 7403070X. High up on the wall of the Faraday cage (7403073X) is this drum-shaped container of the ion source (7403083X). It is mounted at the HV end of the accelerating column through which the ions (usually protons; many other types of ions in the course of its long history) proceed through the Faraday cage wall to the low-energy end (at ground potential) of Linac 1. The 520 kV accelerating voltage was supplied by a SAMES generator (7403074X).

  18. In situ quantitative characterisation of the ocean water column using acoustic multibeam backscatter data

    Science.gov (United States)

    Lamarche, G.; Le Gonidec, Y.; Lucieer, V.; Lurton, X.; Greinert, J.; Dupré, S.; Nau, A.; Heffron, E.; Roche, M.; Ladroit, Y.; Urban, P.

    2017-12-01

    Detecting liquid, solid or gaseous features in the ocean is generating considerable interest in the geoscience community, because of their potentially high economic values (oil & gas, mining), their significance for environmental management (oil/gas leakage, biodiversity mapping, greenhouse gas monitoring) as well as their potential cultural and traditional values (food, freshwater). Enhancing people's capability to quantify and manage the natural capital present in the ocean water goes hand in hand with the development of marine acoustic technology, as marine echosounders provide the most reliable and technologically advanced means to develop quantitative studies of water column backscatter data. This is not developed to its full capability because (i) of the complexity of the physics involved in relation to the constantly changing marine environment, and (ii) the rapid technological evolution of high resolution multibeam echosounder (MBES) water-column imaging systems. The Water Column Imaging Working Group is working on a series of multibeam echosounder (MBES) water column datasets acquired in a variety of environments, using a range of frequencies, and imaging a number of water-column features such as gas seeps, oil leaks, suspended particulate matter, vegetation and freshwater springs. Access to data from different acoustic frequencies and ocean dynamics enables us to discuss and test multifrequency approaches which is the most promising means to develop a quantitative analysis of the physical properties of acoustic scatterers, providing rigorous cross calibration of the acoustic devices. In addition, high redundancy of multibeam data, such as is available for some datasets, will allow us to develop data processing techniques, leading to quantitative estimates of water column gas seeps. Each of the datasets has supporting ground-truthing data (underwater videos and photos, physical oceanography measurements) which provide information on the origin and

  19. Denitrification in the water column of the central Baltic Sea

    DEFF Research Database (Denmark)

    Dalsgaard, Tage; De Brabandere, Loreto; Hall, Per

    2013-01-01

    denitrification ranged from 0.24 to 15.9 nM N2 h−1. Assuming that these rates were valid throughout the anoxic View the MathML source containing zone, depth integrated in situ denitrification rates of 0.06–2.11 mmol N m−2 d−1 were estimated. The thickness of this zone was generally 3–6 m, which is probably what...... View the MathML source or sulfide concentrations were converted to in situ rates using the measured water column concentrations of View the MathML source and sulfide and the actual measured relations between View the MathML source and sulfide concentrations and denitrification rates. In situ...... can be maintained through regular turbulent mixing induced by internal waves at the oxic–anoxic interface. However, layers of up to 55 m thickness with low O2 water (Math...

  20. Digital column readout architectures for hybrid pixel detector readout chips

    International Nuclear Information System (INIS)

    Poikela, T; Plosila, J; Westerlund, T; Buytaert, J; Campbell, M; Gaspari, M De; Llopart, X; Wyllie, K; Gromov, V; Kluit, R; Beuzekom, M van; Zappon, F; Zivkovic, V; Brezina, C; Desch, K; Fu, Y; Kruth, A

    2014-01-01

    In this paper, two digital column architectures suitable for sparse readout of data from a pixel matrix in trigger-less applications are presented. Each architecture reads out a pixel matrix of 256 x 256 pixels with a pixel pitch of 55 μm. The first architecture has been implemented in the Timepix3 chip, and this is presented together with initial measurements. Simulation results and measured data are compared. The second architecture has been designed for Velopix, a readout chip planned for the LHCb VELO upgrade. Unlike Timepix3, this has to be tolerant to radiation-induced single-event effects. Results from post-layout simulations are shown with the circuit architectures

  1. Determination of the hydraulic conductivity in column of undeformed soil by gamma rays transmission

    International Nuclear Information System (INIS)

    Moreira, Anderson C.; Cavalcante, Fabio H.M.; Portezan Filho, Otavio; Coimbra, Melayne M.; Appoloni, Carlos Roberto

    2000-01-01

    The water infiltration process in undeformed soil column and the measurement of redistribution process by gamma rays transmission in different depth allow the determination of Hydraulic Conductivity K(Θ) function, using the Sisson et al. (1980) method. A LRd (dystrophic dark red soil) soil column with 60 cm of height, 10 cm of width and 5 cm of thickness, was analyzed in laboratory, reproducing the field conditions concerning to the water infiltration and redistribution in the soil. The soil moisture content data was obtained with a radioactivity source 241 Am (100 mCi; 59,6 keV), NaI (Tl) 2x2 detector, coupled to an gamma rays spectrometric electronic chain and a measurement table that allowed the vertical displacement of the soil column. The results indicate a growing behavior for K(Θ) in relation to the depth. The collimators had 2 mm and 5 mm diameter for radioactivity source and detector respectively. (author)

  2. Column studies on BTEX biodegradation under microaerophilic and denitrifying conditions

    International Nuclear Information System (INIS)

    Hutchins, S.R.; Moolenaar, S.W.; Rhodes, D.E.

    1992-01-01

    Two column tests were conducted using aquifer material to simulate the nitrate field demonstration project carried out earlier at Traverse City, Michigan. The objectives were to better define the effect nitrate addition had on biodegradation of benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes (BTEX) in the field study, and to determine whether BTEX removal can be enhanced by supplying a limited amount of oxygen as a supplemental electron acceptor. Columns were operated using limited oxygen, limited oxygen plus nitrate, and nitrate alone. In the first column study, benzene was generally recalcitrant compared to the alkylbenzenes (TEX), although some removal did occur. In the second column study, nitrate was deleted from the feed to the column originally receiving nitrate alone and added to the feed of the column originally receiving limited oxygen alone. Although the requirement for nitrate for optimum TEX removal was clearly demonstrated in these columns, there were significant contributions by biotic and abiotic processes other than denitrification which could not be quantified

  3. Stress-Strain Relationship of Synthetic Fiber Reinforced Concrete Columns

    Directory of Open Access Journals (Sweden)

    Rosidawani

    2017-01-01

    Full Text Available Many empirical confinement models for normal and high strength concrete have been developed. Nevertheless, reported studies in the term of confinement of fiber reinforced concrete are limited. Whereas, the use of fiber reinforced concrete in structural elements has become the subject of the research and has indicated positive experiences. Since the stress-strain relationship of concrete in compression is required for analysis of structural members, the study of the stress-strain relationship for synthetic fiber reinforced concrete is substantial. The aim of the study is to examine the capabilities of the various models available in the literature to predict the actual experimental behavior of synthetic fiber reinforced high-strength concrete columns. The experimental data used are the results of the circular column specimens with the spiral spacing and the volume fraction of synthetic fiber as the test variables. The axial stress-strain curves from the tests are then compared with the various models of confinement from the literature. The performance index of each model is measured by using the coefficient of variation (COV concept of stress and strain behavior parameter. Among the confinement models, Cusson model shows the closest valid value of the coefficient of variation.

  4. Kinetics of plasma membrane electron transport in a pulmonary endothelial cell-column.

    Science.gov (United States)

    Olson, L E; Merker, M P; Bongard, R D; Brantmeier, B M; Audi, S H; Linehan, J H; Dawson, C A

    1998-01-01

    Thiazine dyes such as toluidine blue O (TBO) are reduced at the luminal endothelial surface. The purpose of this study was to determine the rate of this reaction in endothelial cells in culture. A multiple indicator dilution method was used to measure the reaction kinetics during transient passage of a TBO-containing bolus through a chromatographic column filled with bovine pulmonary arterial endothelial cells grown on microcarrier beads (cell-column). A bolus containing TBO and an inert extracellular reference indicator (FITC-Dextran) was injected upstream of the cell-column, and the indicator concentrations were measured downstream using on-line photodetection. The effects of column flow rate, PO2, and TBO concentration were studied. The fraction of TBO reduced upon passage through the cell-column decreased with increasing flow indicating that the reaction rate rather than TBO delivery controlled TBO reduction. The fraction of TBO reduced did not change with PO2 or dose in the ranges studied. TBO reduction was about 10 times that for steady state TBO sequestration by these cells which, along with the lack of a PO2 effect indicates that the rapid rate of reduction is not the rate-limiting step in steady state sequestration.

  5. Spinal column damage from water ski jumping

    International Nuclear Information System (INIS)

    Horne, J.; Cockshott, W.P.; Shannon, H.S.

    1987-01-01

    We conducted a radiographic survey of 117 competitive water ski jumpers to determine whether this sport can cause spinal column damage and, if so, whether damage is more likely to occur in those who participate during the period of spinal growth and development (age 15 years or younger). We found a high prevalence of two types of abnormality: Scheuermann (adolescent) spondylodystrophy (present in 26% of the skiers) and vertebral body wedging (present in 34%). The prevalence of adolescent spondylodystrophy increased with the number of years of participation in the sport before age 15 years or less. Of those in this age group who had skied for 5 years or more, 57 showed adolescent spondylodystrophy; of those in the same age group who had skied for 9 years or more, 100% were affected. Wedged vertebrae increased as time of participation increased, regardless of the age at which exposure began. We conclude that competitive water ski jumping may damage the spinal column and that consideration should be given to regulating this sport, particularly for children. (orig.)

  6. Spinal column damage from water ski jumping.

    Science.gov (United States)

    Horne, J; Cockshott, W P; Shannon, H S

    1987-01-01

    We conducted a radiographic survey of 117 competitive water ski jumpers to determine whether this sport can cause spinal column damage and, if so, whether damage is more likely to occur in those who participate during the period of spinal growth and development (age 15 years or younger). We found a high prevalence of two types of abnormality: Scheuermann (adolescent) spondylodystrophy (present in 26% of the skiers) and vertebral body wedging (present in 34%). The prevalence of adolescent spondylodystrophy increased with the number of years of participation in the sport before age 15 years or less. Of those in this age group who had skied for 5 years or more, 57 showed adolescent spondylodystrophy; of those in the same age group who had skied for 9 years or more, 100% were affected. Wedged vertebrae increased as time of participation increased, regardless of the age at which exposure began. We conclude that competitive water ski jumping may damage the spinal column and that consideration should be given to regulating this sport, particularly for children.

  7. Picobubble column flotation of fine coal

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao; Samuel Yu; Xiaohua Zhou; R.Q. Honaker; B.K. Parekh [University of Kentucky, Lexington, KY (United States). Department of Mining Engineering

    2008-01-15

    Froth flotation is widely used in the coal industry to clean -28 mesh (0.6 mm) or -100 mesh (0.15 mm) fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range, nominally 10-100 {mu}m, beyond which the flotation efficiency drops sharply. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. Experimental results have shown that the use of picobubbles in a 5-cm diameter column flotation increased the combustible recovery of a highly floatable coal by up to 10% and that of a poorly floatable coal by up to 40%, depending on the feed rate, collector dosage, and other flotation conditions. 14 refs.

  8. Spinal column damage from water ski jumping

    Energy Technology Data Exchange (ETDEWEB)

    Horne, J.; Cockshott, W.P.; Shannon, H.S.

    1987-11-01

    We conducted a radiographic survey of 117 competitive water ski jumpers to determine whether this sport can cause spinal column damage and, if so, whether damage is more likely to occur in those who participate during the period of spinal growth and development (age 15 years or younger). We found a high prevalence of two types of abnormality: Scheuermann (adolescent) spondylodystrophy (present in 26% of the skiers) and vertebral body wedging (present in 34%). The prevalence of adolescent spondylodystrophy increased with the number of years of participation in the sport before age 15 years or less. Of those in this age group who had skied for 5 years or more, 57 showed adolescent spondylodystrophy; of those in the same age group who had skied for 9 years or more, 100% were affected. Wedged vertebrae increased as time of participation increased, regardless of the age at which exposure began. We conclude that competitive water ski jumping may damage the spinal column and that consideration should be given to regulating this sport, particularly for children. (orig.)

  9. Hydrogen isotope exchange in metal hydride columns

    International Nuclear Information System (INIS)

    Wiswall, R.; Reilly, J.; Bloch, F.; Wirsing, E.

    1977-01-01

    Several metal hydrides were shown to act as chromatographic media for hydrogen isotopes. The procedure was to equilibrate a column of hydride with flowing hydrogen, inject a small quantity of tritium tracer, and observe its elution behavior. Characteristic retention times were found. From these and the extent of widening of the tritium band, the heights equivalent to a theoretical plate could be calculated. Values of around 1 cm were obtained. The following are the metals whose hydrides were studied, together with the temperature ranges in which chromatographic behavior was observed: vanadium, 0 to 70 0 C; zirconium, 500 to 600 0 C; LaNi 5 , -78 to +30 0 C; Mg 2 Ni, 300 to 375 0 C; palladium, 0 to 70 0 C. A dual-temperature isotope separation process based on hydride chromatography was demonstrated. In this, a column was caused to cycle between two temperatures while being supplied with a constant stream of tritium-traced hydrogen. Each half-cycle was continued until ''breakthrough,'' i.e., until the tritium concentration in the effluent was the same as that in the feed. Up to that point, the effluent was enriched or depleted in tritium, by up to 20%

  10. Improved focusing-and-deflection columns

    International Nuclear Information System (INIS)

    Mui, P.H.; Szilagyi, M.

    1995-01-01

    Our earlier design procedures for constructing quadrupole columns are further expanded to include octupole corrector units and ''octupole'' deflectors with no third-order harmonics. The additional complications are finer partitioning of the plates and increased number of voltage controllers. Two sample designs, one having only the additional octupole deflectors and one having both the deflectors and the correctors, are presented and compared to our previous quadrupole system. The additional octupole components are shown to be capable of increasing the current density from 30% to more than 300% for a four-plate system, designed to focus and scan the electron beam over a circular area of 0.25 mm radius. The electron beam is assumed to have an initial divergence of ±2.3 mrad, an initial energy of 6 kV, a total energy spread of 1 eV, and a final acceleration of 30 keV. These systems are then slightly reoptimized for a superficial comparison with the commercially available column by Micrion Corporation. The numerical results indicate a potential for substantial improvements, demonstrating the power of this design procedure. Finally, a discussion is presented on how the individual components can interact with each other to reduce the various aberrations. copyright 1995 American Vacuum Society

  11. Synthesis of focusing-and-deflection columns

    International Nuclear Information System (INIS)

    Szilagyi, M.; Mui, P.H.

    1995-01-01

    Szilagyi and Szep have demonstrated that focusing lenses of high performances can be constructed from a column of circular plate electrodes. Later, Szilagyi modified that system to include dipole, quadrupole, and octupole components by partitioning each plate into eight equal sectors. It has already been shown that the additional quadrupole components can indeed bring about substantial improvements in the focusing of charged particle beams. In this article, that design procedure is expanded to construct columns capable of both focusing and deflecting particle beams by just introducing additional dipole components. In this new design, the geometry of the system remains unchanged. The only extra complication is the demand for more individual controls of the sector voltages. Two sample designs, one for negative ions and one for electrons, are presented showing that in both cases a ±2.3 mrad diverging beam can be focused down to a spot of less than 50 nm in radius over a scanning circular area of radius 0.25 mm. The details of the two systems are given in Sec. IV along with the source conditions. The performance of the negative ion system is found to be comparable to the published data. For the relativistic electron system, the interaction of individual components to reduce various aberrations is investigated. copyright 1995 American Vacuum Society

  12. Visualisation of air–water bubbly column flow using array Ultrasonic Velocity Profiler

    Directory of Open Access Journals (Sweden)

    Munkhbat Batsaikhan

    2017-11-01

    Full Text Available In the present work, an experimental study of bubbly two-phase flow in a rectangular bubble column was performed using two ultrasonic array sensors, which can measure the instantaneous velocity of gas bubbles on multiple measurement lines. After the sound pressure distribution of sensors had been evaluated with a needle hydrophone technique, the array sensors were applied to two-phase bubble column. To assess the accuracy of the measurement system with array sensors for one and two-dimensional velocity, a simultaneous measurement was performed with an optical measurement technique called particle image velocimetry (PIV. Experimental results showed that accuracy of the measurement system with array sensors is under 10% for one-dimensional velocity profile measurement compared with PIV technique. The accuracy of the system was estimated to be under 20% along the mean flow direction in the case of two-dimensional vector mapping.

  13. The effects of carbide column to swelling potential and Atterberg limit on expansive soil with column to soil drainage

    Science.gov (United States)

    Muamar Rifa'i, Alfian; Setiawan, Bambang; Djarwanti, Noegroho

    2017-12-01

    The expansive soil is soil that has a potential for swelling-shrinking due to changes in water content. Such behavior can exert enough force on building above to cause damage. The use of columns filled with additives such as Calcium Carbide is done to reduce the negative impact of expansive soil behavior. This study aims to determine the effect of carbide columns on expansive soil. Observations were made on swelling and spreading of carbides in the soil. 7 Carbide columns with 5 cm diameter and 20 cm height were installed into the soil with an inter-column spacing of 8.75 cm. Wetting is done through a pipe at the center of the carbide column for 20 days. Observations were conducted on expansive soil without carbide columns and expansive soil with carbide columns. The results showed that the addition of carbide column could reduce the percentage of swelling by 4.42%. Wetting through the center of the carbide column can help spread the carbide into the soil. The use of carbide columns can also decrease the rate of soil expansivity. After the addition of carbide column, the plasticity index value decreased from 71.76% to 4.3% and the shrinkage index decreased from 95.72% to 9.2%.

  14. Ion mobility based on column leaching of South African gold tailings dam with chemometric evaluation.

    Science.gov (United States)

    Cukrowska, Ewa M; Govender, Koovila; Viljoen, Morris

    2004-07-01

    New column leaching experiments were designed and used as an alternative rapid screening approach to element mobility assessment. In these experiments, field-moist material was treated with an extracting solution to assess the effects of acidification on element mobility in mine tailings. The main advantage of this version of column leaching experiments with partitioned segments is that they give quick information on current element mobility in conditions closely simulating field conditions to compare with common unrepresentative air-dried, sieved samples used for column leaching experiments. Layers from the tailings dump material were sampled and packed into columns. The design of columns allows extracting leachates from each layer. The extracting solutions used were natural (pH 6.8) and acidified (pH 4.2) rainwater. Metals and anions were determined in the leachates. The concentrations of metals (Ca, Mg, Fe, Mn, Al, Cr, Ni, Co, Zn, and Cu) in sample leachates were determined using ICP OES. The most important anions (NO3-, Cl-, and SO4(2)-) were determined using the closed system izotacophoresis ITP analyser. The chemical analytical data from tailings leaching and physico-chemical data from field measurements (including pH, conductivity, redox potential, temperature) were used for chemometric evaluation of element mobility. Principal factor analysis (PFA) was used to evaluate ions mobility from different layers of tailings dump arising from varied pH and redox conditions. It was found that the results from the partitioned column leaching illustrate much better complex processes of metals mobility from tailings dump than the total column. The chemometric data analysis (PFA) proofed the differences in the various layers leachability that are arising from physico-chemical processes due to chemical composition of tailings dump deposit. Copyright 2004 Elsevier Ltd.

  15. Activity behavior of a HPLC column including α-chymotrypsin immobilized monosized-porous particles

    International Nuclear Information System (INIS)

    Bilici, Z.; Camli, S.T.; Unsal, E.; Tuncel, A.

    2004-01-01

    In this study, a polymer-based, α-chymotrypsin (CT) immobilized HPLC column was prepared as a potential material for affinity-HPLC and chiral separation applications. Monosized-macroporous particles were synthesized as the support material by a relatively new polymerization protocol, the so-called, 'modified seeded polymerization'. The particles were obtained in the form of styrene-glycidyl methacrylate- divinylbenzene terpolymer approximately 11 μm in size. The particles were treated with aqueous ammonia to have primary amine groups on the porous surface. The amine functionalized particles were reacted by glutaraldehyde and the enzyme, CT, was covalently attached. CT carrying monosized-porous particles were slurry packed into the HPLC column 50 mmx4.6 mm in size. Since the activity behavior of immobilized CT played an important role in the enantiomeric separations performed by similar columns, the enzymatic activity behavior of the column produced by our protocol was determined. For this purpose, HPLC column was used as a packed bed reactor and the enzymatic reaction was continuously followed by measuring the absorbance of the output flow by the UV-detector of HPLC. S-shaped absorbance-time curves were obtained by monitoring the reactor output both in dynamic and steady-state periods. The columns with relatively lower immobilized enzyme content were more sensitive to the changes in the operating conditions and responded with more appreciable substrate conversion changes. The maximum reaction rate of the immobilized enzyme was estimated as approximately 25% of the free one by the mathematical model describing the activity behavior of the column. No significant loss was observed in the activity of the immobilized enzyme during the course of the experiments

  16. Hydrothermal synthesis and magneto-optical properties of Ni-doped ZnO hexagonal columns

    International Nuclear Information System (INIS)

    Xu, Xingyan; Cao, Chuanbao

    2015-01-01

    Single crystal Zn 1−x Ni x O (x=0, 0.02, 0.04, 0.06) hexagonal columns have been synthesized by a simple hydrothermal route. The hexagonal columns of the products are about 3 μm in diameter and about 2 μm in thickness. X-ray diffraction (XRD), Ni K-edge XANES spectra and TEM indicate that the as-prepared samples are single-crystalline wurtzite structure and no metallic Ni or other secondary phases are found in the hexagonal columns. Optical absorption and Raman results further confirm the incorporation of Ni 2+ ions in the ZnO lattice. Magnetic measurements indicate that the Zn 1−x Ni x O hexagonal columns exhibited obvious ferromagnetic characteristic at room temperature. The coercive fields (H c ) were obtained to be 135.3, 327.79 and 127.29 Oe for x=0.02, 0.04 and 0.06, respectively. The ferromagnetism was assumed to originate from the exchange interaction between free carriers (holes or electrons) from the valence band and the localized d spins on the Ni ions. - Highlights: • Single crystal Zn 1−x Ni x O (x=0, 0.02, 0.04, 0.06) hexagonal columns were synthesized by a simple hydrothermal method. • The layer-by-layer growth manner of the Zn 1−x Ni x O hexagonal columns was proposed. • Obvious room-temperature ferromagnetic characteristic of Zn 1−x Ni x O are observed and the coercivity (H c ) are 135.3,327.79 and 127.29 Oe for x=0.02, 0.04 and 0.06, respectively. • The exchange interaction between local-spin polarized electrons and conduction electrons is responsible for the room-temperature ferromagnetism in the Zn 1−x Ni x O hexagonal columns

  17. Heat Transfer Analysis for a Fixed CST Column

    International Nuclear Information System (INIS)

    Lee, S.Y.

    2004-01-01

    In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, a transient two-dimensional heat transfer model that includes the conduction process neglecting the convection cooling mechanism inside the crystalline silicotitanate (CST) column has been constructed and heat transfer calculations made for the present design configurations. For this situation, a no process flow condition through the column was assumed as one of the reference conditions for the simulation of a loss-of-flow accident. A series of the modeling calculations has been performed using a computational heat transfer approach. Results for the baseline model indicate that transit times to reach 130 degrees Celsius maximum temperature of the CST-salt solution column are about 96 hours when the 20-in CST column with 300 Ci/liter heat generation source and 25 degrees Celsius initial column temperature is cooled by natural convection of external air as a primary heat transfer mechanism. The modeling results for the 28-in column equipped with water jacket systems on the external wall surface of the column and water coolant pipe at the center of the CST column demonstrate that the column loaded with 300 Ci/liter heat source can be maintained non-boiling indefinitely. Sensitivity calculations for several alternate column sizes, heat loads of the packed column, engineered cooling systems, and various ambient conditions at the exterior wall of the column have been performed under the reference conditions of the CST-salt solution to assess the impact of those parameters on the peak temperatures of the packed column for a given transient time. The results indicate that a water-coolant pipe at the center of the CST column filled with salt solution is the most effective one among the potential design parameters related to the thermal energy dissipation of decay heat load. It is noted that the cooling mechanism at the wall boundary of the column has significant

  18. Investigating the Effect of Column Geometry on Separation Efficiency using 3D Printed Liquid Chromatographic Columns Containing Polymer Monolithic Phases.

    Science.gov (United States)

    Gupta, Vipul; Beirne, Stephen; Nesterenko, Pavel N; Paull, Brett

    2018-01-16

    Effect of column geometry on the liquid chromatographic separations using 3D printed liquid chromatographic columns with in-column polymerized monoliths has been studied. Three different liquid chromatographic columns were designed and 3D printed in titanium as 2D serpentine, 3D spiral, and 3D serpentine columns, of equal length and i.d. Successful in-column thermal polymerization of mechanically stable poly(BuMA-co-EDMA) monoliths was achieved within each design without any significant structural differences between phases. Van Deemter plots indicated higher efficiencies for the 3D serpentine chromatographic columns with higher aspect ratio turns at higher linear velocities and smaller analysis times as compared to their counterpart columns with lower aspect ratio turns. Computational fluid dynamic simulations of a basic monolithic structure indicated 44%, 90%, 100%, and 118% higher flow through narrow channels in the curved monolithic configuration as compared to the straight monolithic configuration at linear velocities of 1, 2.5, 5, and 10 mm s -1 , respectively. Isocratic RPLC separations with the 3D serpentine column resulted in an average 23% and 245% (8 solutes) increase in the number of theoretical plates as compared to the 3D spiral and 2D serpentine columns, respectively. Gradient RPLC separations with the 3D serpentine column resulted in an average 15% and 82% (8 solutes) increase in the peak capacity as compared to the 3D spiral and 2D serpentine columns, respectively. Use of the 3D serpentine column at a higher flow rate, as compared to the 3D spiral column, provided a 58% reduction in the analysis time and 74% increase in the peak capacity for the isocratic separations of the small molecules and the gradient separations of proteins, respectively.

  19. Column properties and flow profiles of a flat, wide column for high-pressure liquid chromatography.

    Science.gov (United States)

    Mriziq, Khaled S; Guiochon, Georges

    2008-04-11

    The design and the construction of a pressurized, flat, wide column for high-performance liquid chromatography (HPLC) are described. This apparatus, which is derived from instruments that implement over-pressured thin layer chromatography, can carry out only uni-dimensional chromatographic separations. However, it is intended to be the first step in the development of more powerful instruments that will be able to carry out two-dimensional chromatographic separations, in which case, the first separation would be a space-based separation, LC(x), taking place along one side of the bed and the second separation would be a time-based separation, LC(t), as in classical HPLC but proceeding along the flat column, not along a tube. The apparatus described consists of a pressurization chamber made of a Plexiglas block and a column chamber made of stainless steel. These two chambers are separated by a thin Mylar membrane. The column chamber is a cavity which is filled with a thick layer (ca. 1mm) of the stationary phase. Suitable solvent inlet and outlet ports are located on two opposite sides of the sorbent layer. The design allows the preparation of a homogenous sorbent layer suitable to be used as a chromatographic column, the achievement of effective seals of the stationary phase layer against the chamber edges, and the homogenous flow of the mobile phase along the chamber. The entire width of the sorbent layer area can be used to develop separations or elute samples. The reproducible performance of the apparatus is demonstrated by the chromatographic separations of different dyes. This instrument is essentially designed for testing detector arrays to be used in a two-dimensional LC(x) x LC(t) instrument. The further development of two-dimension separation chromatographs based on the apparatus described is sketched.

  20. Strengthening of Steel Columns under Load: Torsional-Flexural Buckling

    Directory of Open Access Journals (Sweden)

    Martin Vild

    2016-01-01

    Full Text Available The paper presents experimental and numerical research into the strengthening of steel columns under load using welded plates. So far, the experimental research in this field has been limited mostly to flexural buckling of columns and the preload had low effect on the column load resistance. This paper focuses on the local buckling and torsional-flexural buckling of columns. Three sets of three columns each were tested. Two sets corresponding to the base section (D and strengthened section (E were tested without preloading and were used for comparison. Columns from set (F were first preloaded to the load corresponding to the half of the load resistance of the base section (D. Then the columns were strengthened and after they cooled, they were loaded to failure. The columns strengthened under load (F had similar average resistance as the columns welded without preloading (E, meaning the preload affects even members susceptible to local buckling and torsional-flexural buckling only slightly. This is the same behaviour as of the tested columns from previous research into flexural buckling. The study includes results gained from finite element models of the problem created in ANSYS software. The results obtained from the experiments and numerical simulations were compared.

  1. Materials performance in prototype Thermal Cycling Absorption Process (TCAP) columns

    International Nuclear Information System (INIS)

    Clark, E.A.

    1992-01-01

    Two prototype Thermal Cycling Absorption Process (TCAP) columns have been metallurgically examined after retirement, to determine the causes of failure and to evaluate the performance of the column container materials in this application. Leaking of the fluid heating and cooling subsystems caused retirement of both TCAP columns, not leaking of the main hydrogen-containing column. The aluminum block design TCAP column (AHL block TCAP) used in the Advanced Hydride Laboratory, Building 773-A, failed in one nitrogen inlet tube that was crimped during fabrication, which lead to fatigue crack growth in the tube and subsequent leaking of nitrogen from this tube. The Third Generation stainless steel design TCAP column (Third generation TCAP), operated in 773-A room C-061, failed in a braze joint between the freon heating and cooling tubes (made of copper) and the main stainless steel column. In both cases, stresses from thermal cycling and local constraint likely caused the nucleation and growth of fatigue cracks. No materials compatibility problems between palladium coated kieselguhr (the material contained in the TCAP column) and either aluminum or stainless steel column materials were observed. The aluminum-stainless steel transition junction appeared to be unaffected by service in the AHL block TCAP. Also, no evidence of cracking was observed in the AHL block TCAP in a location expected to experience the highest thermal shock fatigue in this design. It is important to limit thermal stresses caused by constraint in hydride systems designed to work by temperature variation, such as hydride storage beds and TCAP columns

  2. Preparation of polymer monolithic column functionalized by arsonic acid groups for mixed-mode capillary liquid chromatography.

    Science.gov (United States)

    Qin, Zhang-Na; Yu, Qiong-Wei; Wang, Ren-Qi; Feng, Yu-Qi

    2018-04-27

    A mixed-mode polymer monolithic column functionalized by arsonic acid groups was prepared by single-step in situ copolymerization of monomers p-methacryloylaminophenylarsonic acid (p-MAPHA) and pentaerythritol triacrylate (PETA). The prepared poly(p-MAPHA-co-PETA) monolithic column has a homogeneous monolithic structure with good permeability and mechanical stability. Zeta potential measurements reveal that the monolithic stationary phase holds a negative surface charge when the mobile phase resides in the pH range of 3.0-8.0. The retention mechanisms of prepared monolithic column are explored by the separation of selected polycyclic aromatic hydrocarbons (PAHs), nucleosides, and three basic compounds. The results indicate that the column functions in three different separation modes associated with reversed-phase chromatography based on hydrophobic interaction, hydrophilic interaction chromatography, and cation-exchange chromatography. The column efficiency of prepared monolithic column is estimated to be 70,000 and 76,000 theoretical plates/m for thiourea and naphthalene, respectively, at a linear flow velocity of 0.85 mm/s using acetonitrile/H 2 O (85/15, v/v) as the mobile phase. Furthermore, an analysis of the retention factors obtained for the PAHs indicates that the prepared monolithic column exhibits good reproducibility with relative standard deviations of 2.9%, 4.0%, and 4.7% based on run-to-run injections, column-to-column preparation, and batch-to-batch preparation, respectively. Finally, we investigate the separation performance of the proposed monolithic column for select phenols, sulfonamides, nucleobases and nucleosides. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

    Directory of Open Access Journals (Sweden)

    G. Dufour

    2009-03-01

    Full Text Available Formaldehyde (HCHO is an important intermediate compound in the degradation of volatile organic compounds (VOCs in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1 the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×1015 molecule/cm2 and the model performances evaluated using surface measurements are satisfactory (~13%; (2 the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa to a factor of 2 (Poland, the United Kingdom depending on the regions.

  4. Education and training column: the learning collaborative.

    Science.gov (United States)

    MacDonald-Wilson, Kim L; Nemec, Patricia B

    2015-03-01

    This column describes the key components of a learning collaborative, with examples from the experience of 1 organization. A learning collaborative is a method for management, learning, and improvement of products or processes, and is a useful approach to implementation of a new service design or approach. This description draws from published material on learning collaboratives and the authors' experiences. The learning collaborative approach offers an effective method to improve service provider skills, provide support, and structure environments to result in lasting change for people using behavioral health services. This approach is consistent with psychiatric rehabilitation principles and practices, and serves to increase the overall capacity of the mental health system by structuring a process for discovering and sharing knowledge and expertise across provider agencies. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  5. [Lateral column lengthening osteotomy of calcaneus].

    Science.gov (United States)

    Hintermann, B

    2015-08-01

    Lengthening of the lateral column for adduction of forefoot and restoration of the medial arch. Stabilization of the ankle joint complex. Supple flatfoot deformity (posterior tibial tendon dysfunction stage II). Instability of the medial ankle joint complex (superficial deltoid and spring ligament). Posttraumatic valgus and pronation deformity of the foot. Rigid flatfoot deformity (posterior tibial tendon dysfunction stage III and IV). Talocalcaneal and naviculocalcaneal coalition. Osteoarthritis of calcaneocuboid joint. Exposition of calcaneus at sinus tarsi. Osteotomy through sinus tarsi and widening until desired correction of the foot is achieved. Insertion of bone graft. Screw fixation. Immobilization in a cast for 6 weeks. Weight-bearing as tolerated from the beginning. In the majority of cases, part of hindfoot reconstruction. Reliable and stable correction. Safe procedure with few complications.

  6. Yield stress independent column buckling curves

    DEFF Research Database (Denmark)

    Stan, Tudor‐Cristian; Jönsson, Jeppe

    2017-01-01

    of the yield stress is to some inadequate degree taken into account in the Eurocode by specifying that steel grades of S460 and higher all belong to a common set of “raised” buckling curves. This is not satisfying as it can be shown theoretically that the current Eurocode formulation misses an epsilon factor......Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...... in the definition of the normalised imperfection magnitudes. By introducing this factor it seems that the GMNIA analysis and knowledge of the independency of residual stress levels on the yield stress can be brought together and give results showing consistency between numerical modelling and a simple modified...

  7. Calculation of a TBP extraction column

    International Nuclear Information System (INIS)

    Lima Soares, M.L. de.

    1973-01-01

    Problems involving the number of stages in an extraction column and the equipment needed in most aqueous methods of reprocessing of nuclear fuels were studied. A solution for the separation of uranium from fission products in a feed solution that contains these components plus nitric acid, thorium and protactinium is obtained. The program has peculiarities such as treatment of tracer components; acceptance of decontamination and recuperation factors better than the set values for the solution; occurrence of niaxima concentrations; change of key component; criterion for ending of section; corrections for interaction; input data not including concentration estimates of the raffinate and organic extract; set of limitations for the concentrations based on input data to help convergence

  8. Consolidated Fuel Reprocessing Program. Operating experience with pulsed-column holdup estimators

    International Nuclear Information System (INIS)

    Ehinger, M.H.

    1986-01-01

    Methods for estimating pulsed-column holdup are being investigated as part of the Safeguards Assessment task of the Consolidated Fuel Reprocessing Program (CFRP) at the Oak Ridge National Laboratory. The CFRP was a major sponsor of test runs at the Barnwell Nuclear Fuel plant (BNFP) in 1980 and 1981. During these tests, considerable measurement data were collected for pulsed columns in the plutonium purification portion of the plant. These data have been used to evaluate and compare three available methods of holdup estimation

  9. The prediction of concentration profiles for a NIMCIX column absorbing uranium from aqueous solution

    International Nuclear Information System (INIS)

    Wright, R.S.

    1979-01-01

    A procedure is proposed for the prediction of concentration profiles for a countercurrent ion-exchange absorption column, use being made of equilibrium and kinetic data derived from small-scale batch tests. A comparison is presented between the predictions and the measured performance of a column (2,5 m in diameter) absorbing uranium from solution. The method is shown to be adequate for design purposes provided that the data used are from tests in which the solution and resin conditions approximate those for which the plant is being designed [af

  10. Improved Focusing Method for 3-D Imaging using Row–Column-Addressed 2-D Arrays

    DEFF Research Database (Denmark)

    Bouzari, Hamed; Engholm, Mathias; Stuart, Matthias Bo

    2017-01-01

    A row–column-addressed (RCA) 2-D array can be interpreted as two orthogonal 1-D arrays. By transmitting with row elements and receiving the echoes through column elements or vice versa, a rectilinear volume in front of the array can be beamformed. Since the transmit and receive 1-D arrays are ort...... measurements with a PZT λ/2-pitch 3 MHz 62+62 RCA 2-D transducer probe. A synthetic aperture imaging sequence with single element transmissions at a time, is designed for imaging down to 14 cm at a volume rate of 44 Hz....

  11. THE 'TRUE' COLUMN DENSITY DISTRIBUTION IN STAR-FORMING MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    Goodman, Alyssa A.; Pineda, Jaime E.; Schnee, Scott L.

    2009-01-01

    We use the COMPLETE Survey's observations of the Perseus star-forming region to assess and intercompare the three methods used for measuring column density in molecular clouds: near-infrared (NIR) extinction mapping; thermal emission mapping in the far-IR; and mapping the intensity of CO isotopologues. Overall, the structures shown by all three tracers are morphologically similar, but important differences exist among the tracers. We find that the dust-based measures (NIR extinction and thermal emission) give similar, log-normal, distributions for the full (∼20 pc scale) Perseus region, once careful calibration corrections are made. We also compare dust- and gas-based column density distributions for physically meaningful subregions of Perseus, and we find significant variations in the distributions for those (smaller, ∼few pc scale) regions. Even though we have used 12 CO data to estimate excitation temperatures, and we have corrected for opacity, the 13 CO maps seem unable to give column distributions that consistently resemble those from dust measures. We have edited out the effects of the shell around the B-star HD 278942 from the column density distribution comparisons. In that shell's interior and in the parts where it overlaps the molecular cloud, there appears to be a dearth of 13 CO, which is likely due either to 13 CO not yet having had time to form in this young structure and/or destruction of 13 CO in the molecular cloud by the HD 278942's wind and/or radiation. We conclude that the use of either dust or gas measures of column density without extreme attention to calibration (e.g., of thermal emission zero-levels) and artifacts (e.g., the shell) is more perilous than even experts might normally admit. And, the use of 13 CO data to trace total column density in detail, even after proper calibration, is unavoidably limited in utility due to threshold, depletion, and opacity effects. If one's main aim is to map column density (rather than temperature

  12. Bubble properties of heterogeneous bubbly flow in a square bubble column

    NARCIS (Netherlands)

    Bai, Wei; Deen, Niels G.; Kuipers, J.A.M.

    2010-01-01

    The present work focuses on the measurements of bubble properties in heterogeneous bubbly flows in a square bubble column. A four-point optical fibre probe was used for this purpose. The accuracy and intrusive effect of the optical probe was investigated first. The results show that the optical

  13. Determination of the plasma column shape in the Tokamak Novillo cross section by magnetic probes

    International Nuclear Information System (INIS)

    Hernandez Omana, A.

    1993-01-01

    The determination of plasma cross section shape in Tokamaks is an important diagnostic method for equilibrium conditions analysis. In this work, it is obtained a time dependent variation of the plasma column cross section in Novillo Tokamak. The experimental method is based on using one magnetic probe, which is installed inside of the vacuum vessel in a 1 mm. wall thickness stainless steel tube, in the protected region of the limiter shadow. The plasma column cross section is determined measuring the poloidal magnetic field produced by the plasma current. This method, now running for determining the plasma column shape, requires the measurement of magnetic present field outside plasma column. The measurements are carried out from a set of small coils, which are located inside the vacuum chamber in the radial and poloidal direction, so we can measure magnetic field with no current attenuations produced by the penetration time of the stainless steel vacuum chamber. The magnetic probe detect a real time variation of magnetic flux passing through them. In order to obtain the magnetic field values, it is required that the electric signals coming from the magnetic probe be integrated, this operation is carried out by active circuits located between the probe signal and one oscilloscope. The integrated signals can be exhibited photographed on the oscilloscope display. (Author)

  14. Hydrodynamic impact of particle shape in slurry packed liquid chromatography columns

    DEFF Research Database (Denmark)

    Lottes, F.; Arlt, W.; Minceva, M.

    2009-01-01

    We report on a series of flow velocity and efficiency profiles, which were measured across the cross section of preparative chromatographic columns packed with different stationary phase materials using computed tomography. It is shown that this non-invasive technique is very useful for visualiza...

  15. Review of design codes of concrete encased steel short columns under axial compression

    Directory of Open Access Journals (Sweden)

    K.Z. Soliman

    2013-08-01

    Full Text Available In recent years, the use of encased steel concrete columns has been increased significantly in medium-rise or high-rise buildings. The aim of the present investigation is to assess experimentally the current methods and codes for evaluating the ultimate load behavior of concrete encased steel short columns. The current state of design provisions for composite columns from the Egyptian codes ECP203-2007 and ECP-SC-LRFD-2012, as well as, American Institute of Steel Construction, AISC-LRFD-2010, American Concrete Institute, ACI-318-2008, and British Standard BS-5400-5 was reviewed. The axial capacity portion of both the encased steel section and the concrete section was also studied according to the previously mentioned codes. Ten encased steel concrete columns have been investigated experimentally to study the effect of concrete confinement and different types of encased steel sections. The measured axial capacity of the tested ten composite columns was compared with the values calculated by the above mentioned codes. It is concluded that non-negligible discrepancies exist between codes and the experimental results as the confinement effect was not considered in predicting both the strength and ductility of concrete. The confining effect was obviously influenced by the shape of the encased steel section. The tube-shaped steel section leads to better confinement than the SIB section. Among the used codes, the ECP-SC-LRFD-2012 led to the most conservative results.

  16. Laser incising of wood: Impregnation of columns with water-soluble dye

    International Nuclear Information System (INIS)

    Hattori, N.; Ando, K.; Kitayama, S.; Nakamura, Y.

    1994-01-01

    To know whether or not laser incising is a useful pre-treatment technique in impregnating a chemical fluid into lumber, pin holes were made in columns of hinoki (Chamaecyparis obtusa Endl.), sugi (Cryptomeria japonica D. Don), karamatsu (Larix leptolepis Gordon) and douglas-fir (Pseudo-tsuga menziesii Franco) with 1.7 kW CO2 laser, and a water-soluble dye was impregnated into these columns with a local pressure impregnation device. Retentions, and lengths and widths of penetrations from each hole were measured quantitatively. Referring to the results of the preparatory experiment mentioned above, incising patterns for sugi and douglas-fir were designed, and the same water-soluble dye was impregnated into the laser-incised columns as well as into non-incised ones with the vacuum-pressure method to obtain penetrated layers with the target depths completely. As a result, a retention of 200 kg/m3 of dye could be achieved for a column of douglas-fir even if it is a species difficult to impregnate. The penetrated layer also could be formed completely at the depth of the laser incision. Therefore, it is concluded that laser incising can be used for the pre-treatment before impregnation of wood columns. (author)

  17. Compression Behavior of Confined Columns with High-Volume Fly Ash Concrete

    Directory of Open Access Journals (Sweden)

    Sung-Won Yoo

    2017-01-01

    Full Text Available The use of fly ash in ordinary concrete provides practical benefits to concrete structures, such as a gain in long-term strength, reduced hydration heat, improved resistance to chloride, and enhanced workability. However, few studies with high-volume fly ash (HVFA concrete have been conducted that focus on the structural applications such as a column. Thus, there is a need to promote field applications of HVFA concrete as a sustainable construction material. To this end, this study investigated the compressive behavior of reinforced concrete columns that contain HVFA with a 50 percent replacement rate. Six columns were fabricated for this study. The study variables were the HVFA replacement rate, tied steel ratio, and tie steel spacing. The computed ultimate strength by the American Concrete Institute (ACI code conservatively predicted the measured values, and, thus, the existing equation in the ACI code is feasible for confined RC columns that contain HVFA. In addition, an analysis model was calibrated based on the experimental results and is recommended for predicting the stress-strain relationship of confined reinforced concrete columns that contain HVFA.

  18. The annual cycle of plutonium in the water column of a warm, monomictic reservoir

    International Nuclear Information System (INIS)

    Pinder, J.E. III; Alberts, J.J.; Bowling, J.W.; Nelson, D.M.; Orlandini, K.A.

    1992-01-01

    An annual cycle occurs in the 239,240 Pu inventories of the water column of Pond B, an 87-ha warm monomictic reservoir on the US Department of Energy's Savannah River Site in Barnwell Co., South Carolina. The pond has elevated concentrations of 238 Pu and 239,240 Pu in sediments due to releases from former reactor operations and continues to receive additional Pu input from atmospheric deposition. For surface waters, the 239,240 Pu inventory increases following turnover in November to a maximum in March followed by a decline until later summer when minimum inventories occur. For deeper waters, the 239,240 Pu inventories increase rapidly following turnover and reach maximum values in March. The inventories in deeper waters remain large from March until turnover. Maximum inventories for the entire water column occur in March with minimum inventories at turnover in October and November. Turnover results in a redistribution of Pu across water depth but no measurable Pu loss from the water column. Ratios of 238 Pu: 239,240 Pu indicate that the cycle involves primarily Pu from sediment sources with little influence from atmospheric sources. Thus, the cycle represents net remobilization of 239,240 Pu from the sediments to the water column during the oxic, holomictic portion of the year followed by a net loss of Pu from the water column once stratification occurs. (author)

  19. The shapes of column density PDFs. The importance of the last closed contour

    Science.gov (United States)

    Alves, João; Lombardi, Marco; Lada, Charles J.

    2017-10-01

    The probability distribution function of column density (PDF) has become the tool of choice for cloud structure analysis and star formation studies. Its simplicity is attractive, and the PDF could offer access to cloud physical parameters otherwise difficult to measure, but there has been some confusion in the literature on the definition of its completeness limit and shape at the low column density end. In this letter we use the natural definition of the completeness limit of a column density PDF, the last closed column density contour inside a surveyed region, and apply it to a set of large-scale maps of nearby molecular clouds. We conclude that there is no observational evidence for log-normal PDFs in these objects. We find that all studied molecular clouds have PDFs well described by power laws, including the diffuse cloud Polaris. Our results call for a new physical interpretation of the shape of the column density PDFs. We find that the slope of a cloud PDF is invariant to distance but not to the spatial arrangement of cloud material, and as such it is still a useful tool for investigating cloud structure.

  20. Phototrophic microbes form endolithic biofilms in ikaite tufa columns (SW Greenland).

    Science.gov (United States)

    Trampe, Erik; Castenholz, Richard W; Larsen, Jens E N; Kühl, Michael

    2017-11-01

    Marine tufa-columns, formed by the hydrated carbonate mineral ikaite, present a unique alkaline microbial habitat only found in Ikka Fjord (SW-Greenland). The outermost parts of the ikaite columns exhibit a multitude of physico-chemical gradients, and the porous ikaite is colonized by endolithic phototrophic biofilms serving as a substrate for grazing epifauna, where scraping by sea urchins affects overall column-topography. We present a detailed study of the optical microenvironment, spatial organization, and photosynthetic activity of endolithic phototrophs within the porous ikaite crystal matrix. Cyanobacteria and diatoms formed distinctly coloured zones and were closely associated with ikaite-crystals via excretion of exopolymers. Scalar-irradiance measurements showed strong attenuation of visible light (400-700 nm), where only ∼1% of incident irradiance remained at 20 mm depth. Transmission spectra showed in vivo absorption signatures of diatom and cyanobacterial photopigments, which were confirmed by HPLC-analysis. Variable-chlorophyll-fluorescence-imaging showed active photosynthesis with high-light acclimation in the outer diatom layer, and low-light acclimation in the underlying cyanobacterial part. Phototrophs in ikaite thus thrive in polymer-bound endolithic biofilms in a complex gradient microhabitat experiencing constant slow percolation of highly alkaline phosphate-enriched spring water mixing with cold seawater at the tufa-column-apex. We discuss the potential role of these biofilms in ikaite column formation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. The Second Cabauw Intercomparison Campaign for Nitrogen Dioxide Measuring Instruments — CINDI-2 — Overview

    Science.gov (United States)

    Apituley, Arnoud; van Roozendael, Michel; Hendrick, Francois; Kreher, Karin; Richter, Andreas; Wagner, Thomas; Friess, Udo; Participants, Cindi-2

    2017-04-01

    .5 km2, and recent developments in MAXDOAS instruments there was a need for CINDI-2. This campaign was completed in September 2016 and had the goals to: To assess the consistency of slant column measurements of key target species (NO2, O3, O2O2 and HCHO) relevant for the validation of S5P and the future ESA atmospheric Sentinels, from a large number of DOAS and MAXDOAS instruments from all over the world, to study the relationship between remote-sensing column and profile measurements of those species and reference measurements of the same species, and to investigate the horizontal representativeness of MAXDOAS measuring systems in view of their use for the validation of satellite tropospheric measurements on the scale of 25-50 km2. A feature of recent MAXDOAS developments is the use azimuthal scanning, in addition to elevation scanning such as in e.g. the PANDORA type of instruments. This, and the number of participating instruments, that expanded to 42, posed a challenge to the design of the CINDI-2 campaign. To support the campaign goals, NO2 profiles were again provided by NO2 sondes and lidar, as well as through in-situ observations using the Cabauw meteorological tower. Extensive aerosol information was gathered using Raman aerosol lidar as well as by in situ samplers. The analysis of the CINDI-2 data is ongoing. In the presentation a campaign overview will be given. http://www.cesar-observatory.nl http://www.tropomi.eu/science/cindi-2

  2. Plasma pressure in the discharge column of the Novillo Tokamak

    International Nuclear Information System (INIS)

    Gaytan G, E.

    1995-01-01

    The design and construction of an acquisition system for the measurement of the plasma pressure in the Novillo Tokamak is described in detail. The system includes a high voltage ramp generator, a hardware and a software interface with a personal computer. It is used to determine experimentally the variations of the pressure in the plasma column in the cleaning and main discharges. The measurement of the pressure is made with a Pirani sensor adapted to the acquisition hardware and synchronized with the discharge in the plasma. The software is made in object oriented programming as a graphic interface designed to be used easily. It controls the acquisition, records the data, displays in graphic form the results and save the measurements. The graphic interface is a building block that can be used in different acquisition tasks. The ramp generator can deliver a signal of 200 V peak to peak with a current of 200 m A and offset control. The acquisition time is 2.5 μ s for every measurement, 8192 measurements can be stored in the acquisition board for every discharge. (Author)

  3. Behavior of chemicals in the seawater column by shadowscopy

    Science.gov (United States)

    Fuhrer, Mélanie; Aprin, Laurent; Le Floch, Stéphane; Slangen, Pierre; Dusserre, Gilles

    2012-10-01

    Ninety percent of the Global Movement of Goods transit by ship. The transportation of HNS (Hazardous and Noxious Substances) in bulk highly increases with the tanker traffic. The huge volume capacities induce a major risk of accident involving chemicals. Among the latest accidents, many have led to vessels sinking (Ievoli Sun, 2000 - ECE, 2006). In case of floating substances, liquid release in depth entails an ascending two phase flow. The visualization of that flow is complex. Indeed, liquid chemicals have mostly a refractive index close to water, causing difficulties for the assessment of the two phase medium behavior. Several physics aspects are points of interest: droplets characterization (shape evolution and velocity), dissolution kinetics and hydrodynamic vortices. Previous works, presented in the 2010 Speckle conference in Brazil, employed Dynamic Speckle Interferometry to study Methyl Ethyl Ketone (MEK) dissolution in a 15 cm high and 1 cm thick water column. This paper deals with experiments achieved with the Cedre Experimental Column (CEC - 5 m high and 0.8 m in diameter). As the water thickness has been increased, Dynamic Speckle Interferometry results are improved by shadowscopic measurements. A laser diode is used to generate parallel light while high speed imaging records the products rising. Two measurements systems are placed at the bottom and the top of the CEC. The chemical class of pollutant like floaters, dissolvers (plume, trails or droplets) has been then identified. Physics of the two phase flow is presented and shows up the dependence on chemicals properties such as interfacial tension, viscosity and density. Furthermore, parallel light propagation through this disturbed medium has revealed trailing edges vortices for some substances (e.g. butanol) presenting low refractive index changes.

  4. Flooding characteristics of pulsed-sieve plate column. Contributed Paper ED-09

    International Nuclear Information System (INIS)

    Vishnu Anand, P.; Pandey, N.K.; Rajeev, R.; Joyakin, C.V.; Kamachi Mudali, U.; Natarajan, R.

    2014-01-01

    Successful design of a pulsed sieve plate extraction column relies on profound understanding of its hydrodynamic and mass transfer characteristics. Present work outlines a comprehensive study of flooding velocity, a hydrodynamic parameter, as a function of various operating conditions of the column. Experimental studies were carried out using water-normal paraffin hydrocarbon system, under no mass transfer condition, in a pilot plant pulsed sieve plate column equipped with standard plate cartridges. Flooding velocity is characterized here as a function of phase flow ratio and pulse velocity with the aid of characteristic velocity concept together with an exponential function. Flooding points were experimentally identified with satisfactory accuracy using a quantitative method and dispersed phase hold-up was measured by online sampling. To verify the extent of applicability of some of the reported generalized flooding correlations from a design perspective, an analysis was done using our precisely generated experimental flooding data. (author)

  5. Twin column chromatography: A new technique for treating limited amounts of waste

    International Nuclear Information System (INIS)

    Wenzel, U.

    1995-01-01

    The authors set up a chromatographic unit for the decontamination of analytical discards from Am and Pu. The unit is based on the twin column concept, i.e. the chromatographic support is accommodated in two identical columns and the detector placed between the columns. Thus, they could employ the wall effects model allowing the evaluation of breakthrough chromatograms at low effluent concentrations and the determination of the design parameters for the lay-out of the unit. The authors verified the model with the unit and obtained a good agreement between measured and calculated parameters. In the test phase, they processed 47 liters discards, they obtained 56 liters decontaminated waste with a DF Am of 770 and a total DF α of 7,000 and 22 liters eluate which was reduced by evaporation to 0.8 liters

  6. Application of column tests and electrical resistivity methods for leachate transport monitoring

    Directory of Open Access Journals (Sweden)

    Wychowaniak Dorota

    2015-09-01

    Full Text Available Development of the human civilization leads to the pollution of environment. One of the contamination which are a real threat to soil and groundwater are leachates from landfills. In this paper the solute transport through soil was considered. For this purpose, the laboratory column tests of chlorides tracer and leachates transport on two soil samples have been carried out. Furthermore, the electrical resistivity method was applied as auxiliary tool to follow the movements of solute through the soil column what allowed to compare between the results obtained with column test method and electrical resistivity measurements. Breakthrough curves obtained by conductivity and resistivity methods represents similar trends which leads to the conclusion about the suitability of electrical resistivity methods for contamination transport monitoring in soil-water systems.

  7. Novel field emission SEM column with beam deceleration technology

    Energy Technology Data Exchange (ETDEWEB)

    Jiruše, Jaroslav; Havelka, Miloslav; Lopour, Filip

    2014-11-15

    A novel field-emission SEM column has been developed that features Beam Deceleration Mode, high-probe current and ultra-fast scanning. New detection system in the column is introduced to detect true secondary electron signal. The resolution power at low energy was doubled for conventional SEM optics and moderately improved for immersion optics. Application examples at low landing energies include change of contrast, imaging of non-conductive samples and thin layers. - Highlights: • A novel field-emission SEM column has been developed. • Implemented beam deceleration improves the SEM resolution at 1 keV two times. • New column maintains high analytical potential and wide field of view. • Detectors integrated in the column allow gaining true SE and BE signal separately. • Performance of the column is demonstrated on low energy applications.

  8. Novel field emission SEM column with beam deceleration technology

    International Nuclear Information System (INIS)

    Jiruše, Jaroslav; Havelka, Miloslav; Lopour, Filip

    2014-01-01

    A novel field-emission SEM column has been developed that features Beam Deceleration Mode, high-probe current and ultra-fast scanning. New detection system in the column is introduced to detect true secondary electron signal. The resolution power at low energy was doubled for conventional SEM optics and moderately improved for immersion optics. Application examples at low landing energies include change of contrast, imaging of non-conductive samples and thin layers. - Highlights: • A novel field-emission SEM column has been developed. • Implemented beam deceleration improves the SEM resolution at 1 keV two times. • New column maintains high analytical potential and wide field of view. • Detectors integrated in the column allow gaining true SE and BE signal separately. • Performance of the column is demonstrated on low energy applications

  9. Circular Raft Footings Strengthened by Stone Columns under Static Loads

    OpenAIRE

    R. Ziaie Moayed; B. Mohammadi-Haji

    2016-01-01

    Stone columns have been widely employed to improve the load-settlement characteristics of soft soils. The results of two small scale displacement control loading tests on stone columns were used in order to validate numerical finite element simulations. Additionally, a series of numerical calculations of static loading have been performed on strengthened raft footing to investigate the effects of using stone columns on bearing capacity of footings. The bearing capacity of single and group of ...

  10. Estimation of bearing capacity of floating group of stone columns

    OpenAIRE

    Fattah, Mohammed Y.; Al-Neami, Mohammed A.; Shamel Al-Suhaily, Ahmed

    2017-01-01

    Stone column is one of the ground improvement techniques. This technique has a proven performance, short time schedule, durability, constructability and low costs. The stone column technique has been used as a method of reinforcement of soft ground over the past 30 years. The bearing capacity of the stone column still has high level of uncertainties because the existing formulas for the estimation of the bearing capacity are general and do not take into consideration the type of the stone col...

  11. Uncertain Buckling Load and Reliability of Columns with Uncertain Properties

    DEFF Research Database (Denmark)

    Köylüoglu, H. U.; Nielsen, Søren R. K.; Cakmak, A. S.

    Continuous and finite element methods are utilized to determine the buckling load of columns with material and geometrical uncertainties considering deterministic, stochastic and interval models for the bending rigidity of columns. When the bending rigidity field is assumed to be deterministic, t....... for structural design, the lower bound is of crucial interest. The buckling load of fixed-free, simple-supported, pinned-fixed, fixed-fixed columns and a sample frame are calculated....

  12. The design of a new concept chromatography column.

    Science.gov (United States)

    Camenzuli, Michelle; Ritchie, Harald J; Ladine, James R; Shalliker, R Andrew

    2011-12-21

    Active Flow Management is a new separation technique whereby the flow of mobile phase and the injection of sample are introduced to the column in a manner that allows migration according to the principles of the infinite diameter column. A segmented flow outlet fitting allows for the separation of solvent or solute that elutes along the central radial section of the column from that of the sample or solvent that elutes along the wall region of the column. Separation efficiency on the analytical scale is increased by 25% with an increase in sensitivity by as much as 52% compared to conventional separations.

  13. Simulation of startup period of hydrogen isotope separation distillation column

    International Nuclear Information System (INIS)

    Sazonov, A.B.; Kagramanov, Z.G.; Magomedbekov, Eh.P.

    2003-01-01

    Kinetic procedure for the mathematical simulation of start-up regime of rectification columns for molecular hydrogen isotope separation was developed. Nonstationary state (start-up period) of separating column for rectification of multi-component mixture was calculated. Full information on equilibrium and kinetic physicochemical properties of components in separating mixtures was used for the calculations. Profile of concentration of components by height of column in task moment of time was calculated by means of differential equilibriums of nonstationary mass transfer. Calculated results of nonstationary state of column by the 2 m height, 30 mm diameter during separation of the mixture: 5 % protium, 70 % deuterium, 25 % tritium were illustrated [ru

  14. Response of steel box columns in fire conditions

    Directory of Open Access Journals (Sweden)

    Mahmood Yahyai

    2017-05-01

    Full Text Available Effect of elevated temperatures on the mechanical properties of steel, brings the importance of investigating the effect of fire on the steel structures anxiously. Columns, as the main load-carrying part of a structure, can be highly vulnerable to the fire. In this study, the behavior of steel gravity columns with box cross section exposed to fire has been investigated. These kinds of columns are widely used in common steel structures design in Iran. In current study, the behavior of such columns in fire conditions is investigated through the finite element method. To perform this, the finite element model of a steel column which has been previously tested under fire condition, was prepared. Experimental loading and boundary conditions were considered in the model and was analyzed. Results were validated by experimental data and various specimens of gravity box columns were designed according to the Iran’s steel buildings code, and modeled and analyzed using Abaqus software. The effect of width to thickness ratio of column plates, the load ratio and slenderness on the ultimate strength of the column was investigated, and the endurance time was estimated under ISO 834 standard fire curve. The results revealed that an increase in width to thickness ratio and load ratio leads to reduction of endurance time and the effect of width to thickness ratio on the ultimate strength of the column decreases with temperature increase.

  15. Applicability of hydroxylamine nitrate reductant in pulse-column contactors

    International Nuclear Information System (INIS)

    Reif, D.J.

    1983-05-01

    Uranium and plutonium separations were made from simulated breeder reactor spent fuel dissolver solution with laboratory-sized pulse column contactors. Hydroxylamine nitrate (HAN) was used for reduction of plutonium (1V). An integrated extraction-partition system, simulating a breeder fuel reprocessing flowsheet, carried out a partial partition of uranium and plutonium in the second contactor. Tests have shown that acceptable coprocessing can be ontained using HAN as a plutonium reductant. Pulse column performance was stable even though gaseous HAN oxidation products were present in the column. Gas evolution rates up to 0.27 cfm/ft 2 of column cross section were tested and found acceptable

  16. Evaluation of Controller Tuning Methods Applied to Distillation Column Control

    DEFF Research Database (Denmark)

    Nielsen, Kim; W. Andersen, Henrik; Kümmel, Professor Mogens

    A frequency domain approach is used to compare the nominal performance and robustness of dual composition distillation column control tuned according to Ziegler-Nichols (ZN) and Biggest Log Modulus Tuning (BLT) for three binary distillation columns, WOBE, LUVI and TOFA. The scope of this is to ex......A frequency domain approach is used to compare the nominal performance and robustness of dual composition distillation column control tuned according to Ziegler-Nichols (ZN) and Biggest Log Modulus Tuning (BLT) for three binary distillation columns, WOBE, LUVI and TOFA. The scope...

  17. Performance of zeolite scavenge column in Xe monitoring system

    International Nuclear Information System (INIS)

    Wang Qian; Wang Hongxia; Li Wei; Bian Zhishang

    2010-01-01

    In order to improve the performance of zeolite scavenge column, its ability of removal of humidity and carbon dioxide was studied by both static and dynamic approaches. The experimental results show that various factors, including the column length and diameter, the mass of zeolite, the content of water in air, the temperature rise during adsorption, and the activation effectiveness all effect the performance of zeolite column in scavenging humanity and carbon dioxide. Based on these results and previous experience, an optimized design of the zeolite column is made for use in xenon monitoring system. (authors)

  18. Partial strengthening of R.C square columns using CFRP

    Directory of Open Access Journals (Sweden)

    Ahmed Shaban Abdel-Hay

    2014-12-01

    An experimental program was undertaken testing ten square columns 200 × 200 × 2000 mm. One of them was a control specimen and the other nine specimens were strengthened with CFRP. The main parameters studied in this research were the compressive strength of the upper part, the height of the upper poor concrete part, and the height of CFRP wrapped part of column. The experimental results including mode of failure, ultimate load, concrete strain, and fiber strains were analyzed. The main conclusion of this research was, partial strengthening of square column using CFRP can be permitted and gives good results of the column carrying capacity.

  19. Use of a pulsed column contactor as a continuous oxalate precipitation reactor

    International Nuclear Information System (INIS)

    Borda, Gilles; Brackx, Emmanuelle; Boisset, Laurence; Duhamet, Jean; Ode, Denis

    2011-01-01

    Research highlights: → A new type of continuous precipitating device was patented by CEA and tested with reaction between a surrogate nitrate cerium(III) or neodymium(III) and oxalate complexing agent. → Precipitate is confined in aqueous phase emulsion in tetrapropylene hydrogen and does not form deposit on the vessel walls. → Measure size of the precipitate ranges from 20 to 40 μm, it meets the process requirements to filter, and the precipitation reaction is complete. → The laboratory design can be extrapolated to an industrial uranium(IV) and minor actinide(III) coprecipitating column. - Abstract: The current objective of coprecipitating uranium, and minor actinides in order to fabricate a new nuclear fuel by direct (co)precipitation for further transmutation, requires to develop specific technology in order to meet the following requirements: nuclear maintenance, criticity, and potentially high flowrates due to global coprecipitation. A new type of device designed and patented by the CEA was then tested in 2007 under inactive conditions and with uranium. The patent is for organic confinement in a pulsed column (PC). Actually, pulsed columns have been working for a long time in a nuclear environment, as they allow high capacity, sub-critical design (annular geometry) and easy high activity maintenance. The precipitation reaction between the oxalate complexing agent and a surrogate nitrate - cerium(III) or neodymium(III) alone, or coprecipitated uranium(IV) and cerium(III) - occurs within an emulsion created in the device by these two phases flowing with a counter-current chemically inert organic phase (for example tetrapropylene hydrogen-TPH) produced by the stirring action of the column pulsator. The precipitate is confined and thus does not form deposits on the vessel walls (which are also water-repellent); it flows downward by gravity and exits the column continuously into a settling tank. The results obtained for precipitation of cerium or

  20. Reactivity worth of the thermal column of a MTR type swimming pool research reactor using low enriched uranium fuel

    International Nuclear Information System (INIS)

    Ali Khan, L.; Ahmad, N.

    2002-01-01

    The reactivity worth of the thermal column of a typical MTR type swimming pool research reactor using low enriched uranium fuel has been determined by modeling the core using standard computer codes. It was also measured experimentally by operating the reactor in the stall and open ends. The calculated value of the reactivity worth of the thermal column is about 14% greater than the experimentally determined value

  1. DOAS urban pollution measurements

    International Nuclear Information System (INIS)

    Stevens, R.K.; Vossler, T.L.

    1991-01-01

    This paper reports that during July and August of 1990, a differential optical absorption spectrometer (DOAS) made by OPSIS Inc., was used to measure gaseous air pollutants over three separate open paths in Atlanta, GA. Over path 1 and path 2, ozone (O 3 ), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), nitrous acid (HNO 2 ), formaldehyde (HCHO), benzene, toluene, and o-xylene were measured. Nitric oxide (NO) and ammonia (NH 3 ) were monitored over path 3 (143 m). The data quality and data capture depended on the compound being measured and the path over which it was measured. Data quality criteria for each compound were chosen such that the average relative standard deviation would be less than 25%. Data capture ranged from 43% for o-xylene for path 1 to 95% for ozone for path 2. Benzene, toluene, and o-xylene concentrations measured over path 2, which crossed over an interstate highway, were higher than concentrations measured over path 1, implicating emissions from vehicles on the highway as a significant source of these compounds. Federal Reference Method (FRM) instruments were located near the DOAS light receivers and measurements of O 3 , NO 2 , and NO were made concurrently with the DOAS. Correlation coefficients greater than 0.85 were obtained between the DOAS and FRM's; however, there was a difference between the mean values obtained by the two methods for O 3 and NO. A gas chromatograph for measuring volatile organic compounds was operated next to the FRM's. Correlation coefficients of about 0.66 were obtained between the DOAS and GC measurements of benzene and o-xylene

  2. Characterization of tropospheric ozone based on lidar measurement in Hangzhou, East China during the G20 Leaders' Summit

    Science.gov (United States)

    Su, Wenjing; Liu, Cheng; Fan, Guangqiang; Hu, Qihou; Huang, Xin; Dong, Yunsheng; Zhang, Tianshu; Liu, Jianguo

    2017-04-01

    Owing to the G20 (Group of Twenty Finance Ministers and Central Bank Governors) Leaders' Summit (Sep.5th-6th, 2016), a series of strict air quality control measures were implemented in Hangzhou and its surrounding regions from Aug.26th to Sep.6th. A differential absorption lidar was employed to monitor tropospheric ozone in urban Hangzhou during a campaign from Aug. 24th to Sep. 10th, and the satellite-based NO2 VCDs and HCHO VCDs in the troposphere were also retrieved using the Ozone Monitoring Instrument (OMI). During our campaign, six O3 pollution events, which were determined according to the National Ambient Air Quality Standard of China (GB-3095-2012), and two stages with rapid reduction of O3 concentration on Aug. 26th and Sep.4-6th were observed. The temporal variation tendency of O3 concentrations was well reproduced by the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). Typical cases with the abrupt rise and decline of O3 concentrations were analyzed using Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back trajectory, satellite NO2 and HCHO product and the prediction by WRF-Chem model. The transport from northern cities have an important impact on pollutants observed in Hangzhou, and the chemical sensitivity of O3 production, which were approximately evaluated using the ratio of HCHO VCDs to NO2 VCDs in the troposphere, was turned from a mixed VOC-NOx-limited regime into a NOX-limited regime in Hangzhou due to the strict emission control measures.

  3. Poly(norepinephrine)-coated open tubular column for the separation of proteins and recombination human erythropoietin by capillary electrochromatography.

    Science.gov (United States)

    Xiao, Xue; Zhang, Yamin; Wu, Jia; Jia, Li

    2017-12-01

    Recombinant human erythropoietin is an important therapeutic protein with high economic interest due to the benefits provided by its clinical use for the treatment of anemias associated with chronic renal failure and chemotherapy. In this work, a poly(norepinephrine)-coated open tubular column was successfully prepared based on the self-polymerization of norepinephrine under mild alkaline condition, the favorable film forming and easy adhesive properties of poly(norepinephrine). The poly(norepinephrine) coating was characterized by scanning electron microscopy and measurement of the electro-osmotic flow. The thickness of the coating was about 431 nm. The electrochromatographic performance of the poly(norepinephrine)-coated open tubular column was evaluated by separation of proteins. Some basic and acidic proteins including two variants of bovine serum albumin and two variants of β-lactoglobulin achieved separation in the poly(norepinephrine)-coated open tubular column. More importantly, the column demonstrated separation ability for the glycoforms of recombinant human erythropoietin. In addition, the column demonstrated good repeatability with the run-to-run, day-to-day, and column-to-column relative standard deviations of migration times of proteins less than 3.40%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Comparison and Analysis of Steel Frame Based on High Strength Column and Normal Strength Column

    Science.gov (United States)

    Liu, Taiyu; An, Yuwei

    2018-01-01

    The anti-seismic performance of high strength steel has restricted its industrialization in civil buildings. In order to study the influence of high strength steel column on frame structure, three models are designed through MIDAS/GEN finite element software. By comparing the seismic performance and economic performance of the three models, the three different structures are comprehensively evaluated to provide some references for the development of high strength steel in steel structure.

  5. Flow-through Column Experiments and Modeling of Microbially Mediated Cr(VI) Reduction at Hanford 100H

    Science.gov (United States)

    Yang, L.; Molins, S.; Beller, H. R.; Brodie, E. L.; Steefel, C.; Nico, P. S.; Han, R.

    2010-12-01

    Microbially mediated Cr(VI) reduction at the Hanford 100H area was investigated by flow-through column experiments. Three separate experiments were conducted to promote microbial activities associated with denitrification, iron and sulfate reduction, respectively. Replicate columns packed with natural sediments from the site under anaerobic environment were injected with 5mM Lactate as the electron donor and 5 μM Cr(VI) in all experiments. Sulfate and nitrate solutions were added to act as the main electron acceptors in the respective experiments, while iron columns relied on the indigenous sediment iron (and manganese) oxides as electron acceptors. Column effluent solutions were analyzed by IC and ICP-MS to monitor the microbial consumption/conversion of lactate and the associated Cr(VI) reduction. Biogeochemical reactive transport modeling was performed to gain further insights into the reaction mechanisms and Cr(VI) bioreduction rates. All experimental columns showed a reduction of the injected Cr(VI). Columns under denitrifying conditions showed the least Cr(VI) reduction at early stages (simulations indicated that biomass growth completely depleted influent ammonium, and called for an additional source of N to account for the measured reduction rates. Iron columns were the least active with undetectable consumption of the injected lactate, slowest cell growth, and the smallest change in Cr(VI) concentrations during the course of the experiment. In contrast, columns under sulfate-reducing/fermentative conditions exhibited the greatest Cr(VI) reduction capacity. Two sulfate columns evolved to complete lactate fermentation with acetate and propionate produced in the column effluent after 40 days of experiments. These fermenting columns showed a complete removal of injected Cr(VI), visible precipitation of sulfide minerals, and a significant increase in effluent Fe and Mn concentrations. Reactive transport simulations suggested that direct reduction of Cr(VI) by

  6. Global observations of tropospheric BrO columns using GOME-2 satellite data

    Science.gov (United States)

    Theys, N.; van Roozendael, M.; Hendrick, F.; Yang, X.; de Smedt, I.; Richter, A.; Begoin, M.; Errera, Q.; Johnston, P. V.; Kreher, K.; de Mazière, M.

    2011-02-01

    Measurements from the GOME-2 satellite instrument have been analyzed for tropospheric BrO using a residual technique that combines measured BrO columns and estimates of the stratospheric BrO content from a climatological approach driven by O3 and NO2 observations. Comparisons between the GOME-2 results and BrO vertical columns derived from correlative ground-based and SCIAMACHY nadir observations, present a good level of consistency. We show that the adopted technique enables separation of stratospheric and tropospheric fractions of the measured total BrO columns and allows quantitative study of the BrO plumes in polar regions. While some satellite observed plumes of enhanced BrO can be explained by stratospheric descending air, we show that most BrO hotspots are of tropospheric origin, although they are often associated to regions with low tropopause heights as well. Elaborating on simulations using the p-TOMCAT tropospheric chemical transport model, this result is found to be consistent with the mechanism of bromine release through sea salt aerosols production during blowing snow events. No definitive conclusion can be drawn however on the importance of blowing snow sources in comparison to other bromine release mechanisms. Outside polar regions, evidence is provided for a global tropospheric BrO background with column of 1-3 × 1013 molec cm-2, consistent with previous estimates.

  7. Global observations of tropospheric BrO columns using GOME-2 satellite data

    Directory of Open Access Journals (Sweden)

    N. Theys

    2011-02-01

    Full Text Available Measurements from the GOME-2 satellite instrument have been analyzed for tropospheric BrO using a residual technique that combines measured BrO columns and estimates of the stratospheric BrO content from a climatological approach driven by O3 and NO2 observations. Comparisons between the GOME-2 results and BrO vertical columns derived from correlative ground-based and SCIAMACHY nadir observations, present a good level of consistency. We show that the adopted technique enables separation of stratospheric and tropospheric fractions of the measured total BrO columns and allows quantitative study of the BrO plumes in polar regions. While some satellite observed plumes of enhanced BrO can be explained by stratospheric descending air, we show that most BrO hotspots are of tropospheric origin, although they are often associated to regions with low tropopause heights as well. Elaborating on simulations using the p-TOMCAT tropospheric chemical transport model, this result is found to be consistent with the mechanism of bromine release through sea salt aerosols production during blowing snow events. No definitive conclusion can be drawn however on the importance of blowing snow sources in comparison to other bromine release mechanisms. Outside polar regions, evidence is provided for a global tropospheric BrO background with column of 1–3 × 1013 molec cm−2, consistent with previous estimates.

  8. On-column reduction of catecholamine quinones in stainless steel columns during liquid chromatography.

    Science.gov (United States)

    Xu, R; Huang, X; Kramer, K J; Hawley, M D

    1995-10-10

    The chromatographic behavior of quinones derived from the oxidation of dopamine and N-acetyldopamine has been studied using liquid chromatography (LC) with both a diode array detector and an electrochemical detector that has parallel dual working electrodes. When stainless steel columns are used, an anodic peak for the oxidation of the catecholamine is observed at the same retention time as a cathodic peak for the reduction of the catecholamine quinone. In addition, the anodic peak exhibits a tail that extends to a second anodic peak for the catecholamine. The latter peak occurs at the normal retention time of the catecholamine. The origin of this phenomenon has been studied and metallic iron in the stainless steel components of the LC system has been found to reduce the quinones to their corresponding catecholamines. The simultaneous appearance of a cathodic peak for the reduction of catecholamine quinone and an anodic peak for the oxidation of the corresponding catecholamine occurs when metallic iron in the exit frit reduces some of the quinones as the latter exits the column. This phenomenon is designated as the "concurrent anodic-cathodic response." It is also observed for quinones of of 3,4-dihydroxybenzoic acid and probably occurs with o- or p-quinones of other dihydroxyphenyl compounds. The use of nonferrous components in LC systems is recommended to eliminate possible on-column reduction of quinones.

  9. Characterization of the Ljubljana TRIGA thermal column neutron radiographic facility

    International Nuclear Information System (INIS)

    Nemec, T.; Rant, J.; Kristof, E.; Glumac, B.

    1995-01-01

    An extensive characterization of the neutron beam of the existing neutron radiographic facility in the thermal column of the Ljubljana Triga Mark II research reactor is in progress. Neutron beam characteristics are needed to determine the effect of various neutron and gamma radiation on the neutron radiographic image. Commercially available medical scintillator converter screens based on Gd dioxy sulphite as well as Gd metal neutron converters are used to record neutron radiographic image. Thermal, epithermal and fast neutron fluxes were measured using Au and In activation detectors and cadmium ratio is determined. Neutron beam flux profiles are measured by film densitometry and by Au activation detector wires. By exposing films shielded by boral or lead plates individual contributions of thermal, epithermal neutrons and gamma radiation are estimated by densitometric measurements. By recording images of neutron image quality indicators BPI (Beam Purity Indicator) and SI (Sensitivity Indicator) produced by Riso, standard neutron radiography image characteristic are established. In gamma dosimetric measurements thermoluminescent detectors (CaF 2 Mn) are used. (author)

  10. Topology in Synthetic Column Density Maps for Interstellar Turbulence

    Science.gov (United States)

    Putko, Joseph; Burkhart, B. K.; Lazarian, A.

    2013-01-01

    We show how the topology tool known as the genus statistic can be utilized to characterize magnetohydrodyanmic (MHD) turbulence in the ISM. The genus is measured with respect to a given density threshold and varying the threshold produces a genus curve, which can suggest an overall ‘‘meatball,’’ neutral, or ‘‘Swiss cheese’’ topology through its integral. We use synthetic column density maps made from three-dimensional 5123 compressible MHD isothermal simulations performed for different sonic and Alfvénic Mach numbers (Ms and MA respectively). We study eight different Ms values each with one sub- and one super-Alfvénic counterpart. We consider sight-lines both parallel (x) and perpendicular (y and z) to the mean magnetic field. We find that the genus integral shows a dependence on both Mach numbers, and this is still the case even after adding beam smoothing and Gaussian noise to the maps to mimic observational data. The genus integral increases with higher Ms values (but saturates after about Ms = 4) for all lines of sight. This is consistent with greater values of Ms resulting in stronger shocks, which results in a clumpier topology. We observe a larger genus integral for the sub-Alfvénic cases along the perpendicular lines of sight due to increased compression from the field lines and enhanced anisotropy. Application of the genus integral to column density maps should allow astronomers to infer the Mach numbers and thus learn about the environments of interstellar turbulence. This work was supported by the National Science Foundation’s REU program through NSF Award AST-1004881.

  11. On the use of satellite-derived CH4 : CO2 columns in a joint inversion of CH4 and CO2 fluxes

    NARCIS (Netherlands)

    Pandey, S.

    2015-01-01

    We present a method for assimilating total column CH4 : CO2 ratio measurements from satellites for inverse modeling of CH4 and CO2 fluxes using the variational approach. Unlike conventional approaches, in which retrieved CH4 : CO2 are multiplied by model-derived total column CO2 and only the

  12. Temperature of Steel Columns under Natural Fire

    Directory of Open Access Journals (Sweden)

    F. Wald

    2004-01-01

    Full Text Available Current fire design models for time-temperature development within structural elements as well as for structural behaviour are based on isolated member tests subjected to standard fire regimes, which serve as a reference heating, but do not model natural fire. Only tests on a real structure under a natural fire can evaluate future models of the temperature developments in a fire compartment, of the transfer of heat into the structure and of the overall structural behaviour under fire.To study overall structural behaviour, a research project was conducted on an eight storey steel frame building at the  Cardington Building Research Establishment laboratory on January 16, 2003. A fire compartment 11×7 m was prepared on the fourth floor. A fire load of 40 kg/m2 was applied with 100 % permanent mechanical load and 65 % of imposed load. The paper summarises the experimental programme and shows the temperature development of the gas in the fire compartment and of the fire protected columns bearing the unprotected floors.

  13. Selective detachment process in column flotation froth

    Energy Technology Data Exchange (ETDEWEB)

    Honaker, R.Q.; Ozsever, A.V.; Parekh, B.K. [University of Kentucky, Lexington, KY (United States). Dept. of Mining Engineering

    2006-05-15

    The selectivity in flotation columns involving the separation of particles of varying degrees of floatability is based on differential flotation rates in the collection zone, reflux action between the froth and collection zones, and differential detachment rates in the froth zone. Using well-known theoretical models describing the separation process and experimental data, froth zone and overall flotation recovery values were quantified for particles in an anthracite coal that have a wide range of floatability potential. For highly floatable particles, froth recovery had a very minimal impact on overall recovery while the recovery of weakly floatable material was decreased substantially by reductions in froth recovery values. In addition, under carrying-capacity limiting conditions, selectivity was enhanced by the preferential detachment of the weakly floatable material. Based on this concept, highly floatable material was added directly into the froth zone when treating the anthracite coal. The enriched froth phase reduced the product ash content of the anthracite product by five absolute percentage points while maintaining a constant recovery value.

  14. GPR Diagnostics of columns in archaeological contexts

    Science.gov (United States)

    Soldovieri, Francesco; Masini, Nicola; Persico, Raffaele; Catapano, Ilaria

    2017-04-01

    In the last decade the use of Ground Penetrating radar (GPR) applied to cultural heritage has been strongly increasing thanks to both technological development of sensors and softwares for data processing and cultural reasons such as the increasing awareness of conservators and archaeologist of the benefits of this method in terms of reduction of costs and time and risk associated with restoration works. This made GPR a mature technique for investigating different types of works of art and building elements of historical interest, including masonry structures, frescoes, mosaics [1-3], in the context of scientific projects, decision support activities aimed at the diagnosis of decay pathologies, and educational activities. One of the most complex building elements to be investigated by GPR are the columns both for the geometry of the object and for the several expected features to be detected including fractures, dishomogeneities and metallic connection elements. The work deals with the Ground Penetrating Radar diagnostic surveys at the prestigious archaeological site of Pompei. In particular, GPR surveys were carried out in two different areas, Palestra Grande and Tempio di Giove. The first campaign was carried out also as educational activity of the "International School "GEOPHYSICS AND REMOTE SENSING FOR ARCHAEOLOGY". The School aimed at giving the opportunity to scholars, PhD students, researchers and specialists in Geophysics, Remote Sensing and Archaeology to deepen their knowledge and expertise with geophysical and remote sensing techniques for archaeology and cultural heritage documentation and management. This survey was carried on two kinds of columns, with circular and rectangular section in order to detect possible hidden defects affecting their integrity. The second survey was carried out at Tempio di Giove, on request of the Soprintendenza Pompei, in order to gain information about the presence of reinforcement structures, which may be put inside the

  15. CHROMIUM(VI REDUCTION BY A MIXED CULTURE OF SULFATE REDUCING BACTERIA DEVELOPED IN COLUMN REACTOR

    Directory of Open Access Journals (Sweden)

    Cynthia Henny

    2008-03-01

    Full Text Available A lactate enriched mixed sulfate reducing bacteria (SRB culture was examined for the reduction of Cr(VI in a continuous flow system. The influent was mineral salts media added with lactate and sulfate with amounts of 8 and 6 mM respectively as electron donor and electron acceptor. The SRB culture was allowed to stabilize in the column before adding the Cr(VI to the influent. Chromium and sulfate reduction and lactate oxidation were examined by measuring the concentrations of Cr(Vl, sulfate and lactate in the influent and the effluent over time. The experiment was discontinued when Cr(VI concentration in the effiuent was breakthrough. In the absence of Cr(VI, sulfate was not completely reduced in the column, although lactate was completely oxidized and acetate as an intermediate product was not often detected. Almost all of Cr(VI loaded was reduced in the column seeded with the SRB culture at influent Cr(VI concentrations of 192,385 and769 mM. There was no significant Cr(VI loss in the control column, indicating that Cr(VI removal was due to the reduction of Cr(VI to Cr (lll by the SRB culture. The instantaneous Cr(VI removal decreased to a minimum of 32%, 24 days after the influent Cr(VI concentration was increased to 1540 mM, ancl sulfate removal efficiency decreased to a minimum of 17%. The SRB population in the column decreased 100 days after C(VI was added to the column. The total mass of Cr(VI reduced was approximately 878 mmol out of 881 mmol of Cr(Vl loaded in 116 days. The results clearly show that our developed SRB culture could reduced Cr(Vl considerably.

  16. Performance of soft clay stabilized with sand columns treated by silica fume

    Directory of Open Access Journals (Sweden)

    Samueel Zeena

    2018-01-01

    Full Text Available In many road construction projects, if weak soil exists, then uncontrollable settlement and critical load carrying capacity are major difficult problems to the safety and serviceability of roads in these areas. Thus ground improvement is essential to achieve the required level of performance. The paper presents results of the tests of four categories. First category was performed on saturated soft bed of clay without any treatment, the second category shed light on the improvement achieved in loading carrying capacity and settlement as a result of reinforcing with conventional sand columns at area replacement ratio = 0.196. The third set investigates the bed reinforced by sand columns stabilized with dry silica fume at different percentages (3, 5 and 7% and the fourth set investigates the behavior of sand columns treated with slurry silica fume at two percentages (10 and 12%. All sand columns models were constructed at (R.D= 60%. Model tests were performed on bed of saturated soil prepared at undrained shear strength between 16-20 kPa for all models. For all cases, the model test was loaded gradually by stress increments up to failure. Stress deformation measurements are recorded and analyzed in terms of bearing improvement ratio and settlement reduction ratio. Optimum results were indicated from soil treated with sand columns stabilized with 7% dry silica fume at medium state reflecting the highest bearing improvement ratio (3.04 and the settlement reduction ratio (0.09 after 7 days curing. While soil treated with sand columns stabilized with 10% slurry silica fume provided higher bearing improvement ratio 3.13 with lower settlement reduction ratio of 0.57 after 7-days curing.

  17. Water column methanotrophy controlled by a rapid oceanographic switch

    NARCIS (Netherlands)

    Steinle, L.; Graves, C.A.; Treude, T.; Ferré, B.; Biastoch, A.; Bussmann, I.; Berndt, C.; Krastel, S.; James, R.H.; Behrens, E.; Böning, C.W.; Greinert, J.; Sapart, C.-J.; Scheinert, M.; Sommer, S.; Lehmann, M.F.; Niemann, H.

    2015-01-01

    From the seabed to the water column, where it may be consumed by aerobic methanotrophic bacteria. The size and activity of methanotrophic communities, which determine the amount of methane consumed in the water column,are thought to be mainly controlled by nutrient and redoxdynamics3–7. Here, we

  18. Comparison of monolithic silica and polymethacrylate capillary columns for LC

    Czech Academy of Sciences Publication Activity Database

    Moravcová, D.; Jandera, P.; Urban, J.; Planeta, Josef

    2004-01-01

    Roč. 27, 10-11 (2004), s. 789-800 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA203/02/0023 Keywords : monolithic column s * capillary HPLC * column testing Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.927, year: 2004

  19. Alpha-contained laboratory scale pulse column facility for SRL

    International Nuclear Information System (INIS)

    Reif, D.J.; Cadieux, J.R.; Fauth, D.J.; Thompson, M.C.

    1980-01-01

    For studying solvent extraction processes, a laboratory-sized pulse column facility was constructed at the Savannah River Laboratory. This facility, in conjunction with existing miniature mixer-settler equipment and the centrifugal contactor facility currently under construction at SRL, provides capability for cross comparison of solvent extraction technology. This presentation describes the design and applications of the Pulse Column Facility at SRL

  20. Hydrodynamic chromatography of polystyrene microparticles in micropillar array columns

    NARCIS (Netherlands)

    Op de Beeck, Jeff; de Malsche, Wim; Vangelooven, Joris; Gardeniers, Johannes G.E.; Desmet, Gert

    2010-01-01

    We report on the possibility to perform HDC in micropillar array columns and the potential advantages of such a system. The HDC performance of a pillar array column with pillar diameter = 5 μm and an interpillar distance of 2.5 μm has been characterized using both a low MW tracer (FITC) and

  1. Simulators of tray distillation columns as tools for interpreting ...

    African Journals Online (AJOL)

    ... at 0.05 m intervals were determined from top to the bottom of simulators of tray distillation columns exposed to 20 mCi of 137 Cs. Signals generated from the simulators were identical with the experimental signals obtained from the Stabilizer Column of the crude oil distillation unit at the Tema Oil Refinery Ghana Limited.

  2. Ultrasonic testing device having an adjustable water column

    Science.gov (United States)

    Roach, Dennis P.; Neidigk, Stephen O.; Rackow, Kirk A.; Duvall, Randy L.

    2015-09-01

    An ultrasonic testing device having a variable fluid column height is disclosed. An operator is able to adjust the fluid column height in real time during an inspection to to produce optimum ultrasonic focus and separate extraneous, unwanted UT signals from those stemming from the area of interest.

  3. Dynamic stability of a lightly damped column trapped by a ...

    African Journals Online (AJOL)

    In this paper we initiate an analytical approach for determining the dynamic buckling load of a finite viscously damped column acted upon by a harmonically slowly varying explicitly time dependent load. The viscous damping is considered light and the column rests on an elastic foundation that produces a nonlinear ...

  4. Localized giant cell tumors in the spinal column radiologic presentation

    International Nuclear Information System (INIS)

    Fernandez Echeverria, M.A.; Parra Blanco, J.A.; Pagola Serrano, M.A.; Mellado Santos, J.M.; Bueno Lopez, J.; Gonzalez Tutor, A.

    1994-01-01

    Given the uncommonness of the location of giant cell tumors (GCT) in the spinal column and the limited number of studies published, we present a case of GCT located in the spinal column, which involved both vertebral bodies and partially destroyed the adjacent rib. (Author)

  5. Monitoring aged reversed-phase high performance liquid chromatography columns

    NARCIS (Netherlands)

    Bolck, A; Smilde, AK; Bruins, CHP

    1999-01-01

    In this paper, a new approach for the quality assessment of routinely used reversed-phase high performance liquid chromatography columns is presented. A used column is not directly considered deteriorated when changes in retention occur. If attention is paid to the type and magnitude of the changes,

  6. Nondestructive evaluation of warm mix asphalt through resonant column testing.

    Science.gov (United States)

    2014-02-01

    Non-destructive testing has been used for decades to characterize engineering properties of hot-mix asphalt. Among such tests is the resonant column (RC) test, which is commonly used to characterize soil materials. The resonant column device at Penn ...

  7. Retrofit of distillation columns in biodiesel production plants

    International Nuclear Information System (INIS)

    Nguyen, Nghi; Demirel, Yasar

    2010-01-01

    Column grand composite curves and the exergy loss profiles produced by the Column-Targeting Tool of the Aspen Plus simulator are used to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a biodiesel production plant. Effectiveness of the retrofits is assessed by means of thermodynamics and economic improvements. We have considered a biodiesel plant utilizing three distillation columns to purify biodiesel (fatty acid methyl ester) and byproduct glycerol as well as reduce the waste. The assessments of the base case simulation have indicated the need for modifications for the distillation columns. For column T202, the retrofits consisting of a feed preheating and reflux ratio modification have reduced the total exergy loss by 47%, while T301 and T302 columns exergy losses decreased by 61% and 52%, respectively. After the retrofits, the overall exergy loss for the three columns has decreased from 7491.86 kW to 3627.97 kW. The retrofits required a fixed capital cost of approximately $239,900 and saved approximately $1,900,000/year worth of electricity. The retrofits have reduced the consumption of energy considerably, and leaded to a more environmentally friendly operation for the biodiesel plant considered.

  8. Dynamics and Control of Distillation Columns - A Critical Survey

    Directory of Open Access Journals (Sweden)

    Sigurd Skogestad

    1997-07-01

    Full Text Available Distillation column dynamics and control have been viewed by many as a very mature or even dead field. However, as is discussed in this paper significant new results have appeared over the last 5-10 years. These results include multiple steady states and instability in simple columns with ideal thermodynamics (which was believed to be impossible, the understanding of the difference between various control configurations and the systematic transformation between these, the feasibility of using the distillate-bottom structure, for control (which was believed to be impossible, the importance of flow dynamics for control studies, the fundamental problems in identifying models from open-loops responses, the use of simple regression estimators to estimate composition from temperatures, and an improved general understanding of the dynamic behavior of distillation columns which includes a better understanding of the fundamental difference between internal and external flow, simple formulas for estimating the dominant time constant, and a derivation of the linearizing effect of logarithmic transformations. These issues apply to all columns, even for ideal mixtures and simple columns with only two products. In addition, there have been significant advances for cases with complex thermodynamics and complex column configurations. These include the behavior and control of azeotropic distillation columns, and the possible complex dynamics of nonideal mixtures and of interlinked columns. However, both for the simple and more complex cases there are still a number of areas where further research is needed.

  9. Gas chromatographic column for the Viking 1975 molecular analysis experiment

    Science.gov (United States)

    Novotny, M.; Hayes, J. M.; Bruner, F.; Simmonds, P. G.

    1975-01-01

    A gas chromatographic column has been developed for use in the remote analysis of the Martian surface. The column, which utilizes a liquid-modified organic adsorbent (Tenax) as the stationary phase, provides efficient transmission and resolution of nanogram quantities of organic materials in the presence of millionfold excesses of water and carbon dioxide.

  10. Cow-in-a-Column – A Synthetic Food Replicator

    Data.gov (United States)

    National Aeronautics and Space Administration — The project tested the concept for combining waste degradation and food production in a single reactor or column, i.e., a "Cow-in-a-Column".  The inputs could...

  11. A Modeling Framework for Conventional and Heat Integrated Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2013-01-01

    In this paper, a generic, modular model framework for describing fluid separation by distillation is presented. At present, the framework is able to describe a conventional distillation column and a heat-integrated distillation column, but due to a modular structure the database can be further...

  12. Graph Modelling Approach: Application to a Distillation Column

    DEFF Research Database (Denmark)

    Hovelaque, V.; Commault, C.; Bahar, Mehrdad

    1997-01-01

    Introduction, structured systems and digraphs, distillation column model, generic input-output decoupling problem, generic disturbance rejection problem, concluding remarks.......Introduction, structured systems and digraphs, distillation column model, generic input-output decoupling problem, generic disturbance rejection problem, concluding remarks....

  13. Measurement

    NARCIS (Netherlands)

    Boumans, M.; Durlauf, S.N.; Blume, L.E.

    2008-01-01

    Measurement theory takes measurement as the assignment of numbers to properties of an empirical system so that a homomorphism between the system and a numerical system is established. To avoid operationalism, two approaches can be distinguished. In the axiomatic approach it is asserted that if the

  14. Investigations on the propagation of free surface boiling in a vertical superheated liquid column

    Energy Technology Data Exchange (ETDEWEB)

    Das, P.K.; Bhat, G.S.; Arakeri, V.H.

    1987-04-01

    Some experimental studies on boiling propagation in a suddenly depressurized superheated vertical liquid column are reported. The propagation velocity of this phase change has been measured using an optical method. This velocity is strongly dependent on liquid superheat, liquid purity and test section size. The measured velocities of less than 5 m s/sup -1/ are significantly lower than the sonic velocity. Present observations suggest that the dominant mechanism for boiling propagation is convection.

  15. Investigations on the propagation of free surface boiling in a vertical superheated liquid column

    International Nuclear Information System (INIS)

    Das, P.K.; Bhat, G.S.; Arakeri, V.H.

    1987-01-01

    Some experimental studies on boiling propagation in a suddenly depressurized superheated vertical liquid column are reported. The propagation velocity of this phase change has been measured using an optical method. This velocity is strongly dependent on liquid superheat, liquid purity and test section size. The measured velocities of less than 5 m s -1 are significantly lower than the sonic velocity. Present observations suggest that the dominant mechanism for boiling propagation is convection. (author)

  16. HEAT TRANSFER ANALYSIS FOR FIXED CST AND RF COLUMNS

    International Nuclear Information System (INIS)

    Lee, S

    2007-01-01

    In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, transient and steady state two-dimensional heat transfer models have been constructed for columns loaded with cesium-saturated crystalline silicotitanate (CST) or spherical Resorcinol-Formaldehyde (RF) beads and 6 molar sodium tank waste supernate. Radiolytic decay of sorbed cesium results in heat generation within the columns. The models consider conductive heat transfer only with no convective cooling and no process flow within the columns (assumed column geometry: 27.375 in ID with a 6.625 in OD center-line cooling pipe). Heat transfer at the column walls was assumed to occur by natural convection cooling with 35 C air. A number of modeling calculations were performed using this computational heat transfer approach. Minimal additional calculations were also conducted to predict temperature increases expected for salt solution processed through columns of various heights at the slowest expected operational flow rate of 5 gpm. Results for the bounding model with no process flow and no active cooling indicate that the time required to reach the boiling point of ∼130 C for a CST-salt solution mixture containing 257 Ci/liter of Cs-137 heat source (maximum expected loading for SCIX applications) at 35 C initial temperature is about 6 days. Modeling results for a column actively cooled with external wall jackets and the internal coolant pipe (inlet coolant water temperature: 25 C) indicate that the CST column can be maintained non-boiling under these conditions indefinitely. The results also show that the maximum temperature of an RF-salt solution column containing 133 Ci/liter of Cs-137 (maximum expected loading) will never reach boiling under any conditions (maximum predicted temperature without cooling: 88 C). The results indicate that a 6-in cooling pipe at the center of the column provides the most effective cooling mechanism for reducing the maximum

  17. Characterization of retentivity of reversed phase liquid chromatography columns.

    Science.gov (United States)

    Ying, P T; Dorsey, J G

    1991-03-01

    There are dozens of commercially available reversed phase columns, most marketed as C-8 or C-18 materials, but with no useful way of classifying their retentivity. A useful way of ranking these columns in terms of column "strength" or retentivity is presented. The method utilizes a value for ln k'(w), the estimated retention of a solute from a mobile phase of 100% water, and the slope of the plot of ln k' vsE(T)(30), the solvent polarity. The method is validated with 26 solutes varying in ln k'(w) from about 2 to over 20, on 14 different reversed phase columns. In agreement with previous work, it is found that the phase volume ratio of the column is the most important parameter in determining retentivity. It is strongly suggested that manufacturers adopt a uniform method of calculating this value and that it be made available in advertising, rather than the uninterpretable "% carbon".

  18. A Modelling Framework for Conventional and Heat Integrated Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2013-01-01

    of hydrocarbons such as separations of equimolar mixtures of benzene/toluene or propane/propene described by simple models, a generic, modular, model framework is presented in this work. At present, the framework is able to describe a conventional distillation column, a mechanical vapor recompression column......Diabatic operation of distillation columns can lead to signicant reductions in energy utilization and operation cost compared to conventional (adiabatic) distillation columns, at an expense of an increased complexity of design and operation. The earliest diabatic distillation conguration dates back...... to the late 70s, and various dierent congurations have appeared since. However, at present, no full-scale diabatic distillation columns are currently operating in the industry. Current studies related to alternative distillation congurations report very dierent gures for potential energy savings which...

  19. Evaluation of an ambient air sampling system for tritium (as tritiated water vapor) using silica gel adsorbent columns

    International Nuclear Information System (INIS)

    Patton, G.W.; Cooper, A.T.; Tinker, M.R.

    1995-08-01

    Ambient air samples for tritium analysis (as the tritiated water vapor [HTO] content of atmospheric moisture) are collected for the Hanford Site Surface Environmental Surveillance Project (SESP) using the solid adsorbent silica gel. The silica gel has a moisture sensitive indicator which allows for visual observation of moisture movement through a column. Despite using an established method, some silica gel columns showed a complete change in the color indicator for summertime samples suggesting that breakthrough had occurred; thus a series of tests was conducted on the sampling system in an environmental chamber. The purpose of this study was to determine the maximum practical sampling volume and overall collection efficiency for water vapor collected on silica gel columns. Another purpose was to demonstrate the use of an impinger-based system to load water vapor onto silica gel columns to provide realistic analytical spikes and blanks for the Hanford Site SESP. Breakthrough volumes (V b ) were measured and the chromatographic efficiency (expressed as the number of theoretical plates [N]) was calculated for a range of environmental conditions. Tests involved visual observations of the change in the silica gel's color indicator as a moist air stream was drawn through the column, measurement of the amount of a tritium tracer retained and then recovered from the silica gel, and gravimetric analysis for silica gel columns exposed in the environmental chamber

  20. Hydraulic conductivity of indeformed soil columns determination by gamma ray transmission

    International Nuclear Information System (INIS)

    Moreira, Anderson Camargo; Moraes Cavalcante, Fabio Henrique de; Rocha, Marcos Correa da; Filho, Otavio Portezan; Quinones, Fernando Rodolfo Espinosa; Appoloni, Carlos Roberto

    2000-01-01

    The spatial variation of the soil structure influences the water movement through its porous geometry, which could cause problems in the development of agricultural cultures and also accelerate processes of soil erosion. The gamma ray transmission method has established efficiency for the non-destructive measurement of moisture temporal and space evolution, and consequently in the determination of the hydraulic conductivity of the soil, K(θ). Columns of undisturbed soil (approximately 0.11 x 0.06 x 0.60 m) were removed from a trench in the Campus of Londrina State University. The used soil was classified like distrophic dark red soil (LRd). The indeformed soil columns were wrapped up with paraffin and gauze and were fixed on the table of measurement. The water vertical infiltration in the soil was accomplished by maintaining a water layer of approximately 0.01 m over an area of soil of 75 x 10 -4 m 2 . Layers of filter papers and foam controlled the flow of water in the soil surface. After the conclusion of the infiltration, began the process of redistribution of the water in the soil column, with the objective to determine the function K(θ) in relation to the depth in the column. The moisture profiles θ(z,t) are obtained using a radioactive source of 241 Am (3.7 x 10 9 Bq; 0.0596 MeV), spectrometric electronic chain, a 2x2'' NaI(Tl) detector and a measurements table , which allows the sample to move vertically. The hydraulic conductivity function was determined, applying the Sisson model , at 10 levels in the soil column and the results exhibit an increase of K(θ) with depth. (author)