WorldWideScience

Sample records for water vapour removed

  1. Sodium removal from CSRDM lower part by water vapour - CO2 process

    International Nuclear Information System (INIS)

    Sundar Raj, S.I.; Sreedhar, B.K.; Gurumoorthy, K.; Rajan, K.K.; Kalyanasundaram, P.; Rajan, M.; Vaidyanathan, G.

    2006-01-01

    Sodium is the primary and secondary coolant in fast reactors. Primary and secondary circuits components like Control and Safety Rod Drive Mechanism (CSRDM), pumps, heat exchangers etc. handle liquid sodium. Sodium has good affinity to oxygen and reacts vigorously with water. Hence sodium cleaning is the first and important activity in the maintenance of the components. In reactor components this cleaning process also helps in removing a major part of radioactive contaminants after which they are subjected to chemical decontamination. There are several methods available for removing sodium from components. Out of these, the water vapour-CO 2 process is selected for large components such as pumps, heat exchangers etc. while steam cleaning is used for the core sub assemblies. The cleaning processes are to be closely monitored to ensure safety because the release of hydrogen is to be kept below 4 % during the process. This paper discusses the in house facility and the experience in the successful use of the process in the cleaning of CSRDM. (author)

  2. Water vapour loss measurements on human skin.

    NARCIS (Netherlands)

    Valk, Petrus Gerardus Maria van der

    1984-01-01

    In this thesis, the results of a series of investigations into the barrier function of human skin are presented. In these investigations, the barrier function was assessed by water vapour loss measurements of the skin using a method based on gradient estimation.... Zie: Summary and conclusions

  3. Vapour Removal from the Greenhouse Using Forced Ventilation when Applying a Thermal Screen

    NARCIS (Netherlands)

    Campen, J.B.

    2008-01-01

    The objective of this study is to dimension a system capable of removing water vapour mainly generated by evaporation of the crop when a thermal screen is applied. The humid greenhouse air is replaced by cold dry outside air using an air distribution system. The dry air is injected above the

  4. The impact of water vapour on climate

    International Nuclear Information System (INIS)

    Zittel, W.; Altmann, M.

    1994-01-01

    Do water vapour emissions from a solar hydrogen system affect the climate? This question was investigated by the authors. They state: The comparison with natural emissions by evaporation shows that emissions caused by energy generation, regardless of whether they stem from fossil, nuclear or regenerative energy systems, are negligible with a proportion of 0.005%. On the other hand, carbon dioxide emissions with a proportion of 4%, constitute a factor which already impedes the natural cycle. (orig.) [de

  5. Water vapour measurements during POLINAT 1

    Energy Technology Data Exchange (ETDEWEB)

    Ovarlez, J.; Ovarlez, H. [Centre National de la Recherche Scientifique, 91 - Palaiseau (France). Lab. de Meteorologie Dynamique

    1997-12-31

    The POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor)1 experiment has been performed within the framework of the Environment Programme of the Commission of the European Community. It was devoted to the study of the pollution from aircraft in the North Atlantic flight corridor, in order to investigate the impact of pollutants emitted by aircraft on the concentrations of ozone and other trace gases in the upper troposphere and lower stratosphere. For that experiment the water vapour content was measured with a frost-point hygrometer on board of the DLR Falcon research aircraft. This instrument is described, and some selected results are given. (author) 19 refs.

  6. Water vapour measurements during POLINAT 1

    Energy Technology Data Exchange (ETDEWEB)

    Ovarlez, J; Ovarlez, H [Centre National de la Recherche Scientifique, 91 - Palaiseau (France). Lab. de Meteorologie Dynamique

    1998-12-31

    The POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor)1 experiment has been performed within the framework of the Environment Programme of the Commission of the European Community. It was devoted to the study of the pollution from aircraft in the North Atlantic flight corridor, in order to investigate the impact of pollutants emitted by aircraft on the concentrations of ozone and other trace gases in the upper troposphere and lower stratosphere. For that experiment the water vapour content was measured with a frost-point hygrometer on board of the DLR Falcon research aircraft. This instrument is described, and some selected results are given. (author) 19 refs.

  7. Carbon dioxide and water vapour characteristics on the west coast ...

    Indian Academy of Sciences (India)

    Carbon dioxide, water vapour, air temperature and wind measurements at 10 Hz sampling rate were carried out over the ... seasonal and annual variations in the CO2 bal- ance. Hence, it is .... motion below produced by shear stress near the.

  8. GPS Tomography: Water Vapour Monitoring for Germany

    Science.gov (United States)

    Bender, Michael; Dick, Galina; Wickert, Jens; Raabe, Armin

    2010-05-01

    Ground based GPS atmosphere sounding provides numerous atmospheric quantities with a high temporal resolution for all weather conditions. The spatial resolution of the GPS observations is mainly given by the number of GNSS satellites and GPS ground stations. The latter could considerably be increased in the last few years leading to more reliable and better resolved GPS products. New techniques such as the GPS water vapour tomography gain increased significance as data from large and dense GPS networks become available. The GPS tomography has the potential to provide spatially resolved fields of different quantities operationally, i. e. the humidity or wet refractivity as required for meteorological applications or the refraction index which is important for several space based observations or for precise positioning. The number of German GPS stations operationally processed by the GFZ in Potsdam was recently enlarged to more than 300. About 28000 IWV observations and more than 1.4 millions of slant total delay data are now available per day with a temporal resolution of 15 min and 2.5 min, respectively. The extended network leads not only to a higher spatial resolution of the tomographically reconstructed 3D fields but also to a much higher stability of the inversion process and with that to an increased quality of the results. Under these improved conditions the GPS tomography can operate continuously over several days or weeks without applying too tight constraints. Time series of tomographically reconstructed humidity fields will be shown and different initialisation strategies will be discussed: Initialisation with a simple exponential profile, with a 3D humidity field extrapolated from synoptic observations and with the result of the preceeding reconstruction. The results are compared to tomographic reconstructions initialised with COSMO-DE analyses and to the corresponding model fields. The inversion can be further stabilised by making use of independent

  9. Low pressure water vapour plasma treatment of surfaces for biomolecules decontamination

    DEFF Research Database (Denmark)

    Fumagalli, F; Kylian, O; Amato, Letizia

    2012-01-01

    Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can...... be achieved using pure H2O or Ar/H2O mixtures at low temperatures with removal rates comparable to oxygen-based mixtures. Particle fluxes (Ar+ ions, O and H atomic radicals and OH molecular radicals) from water vapour discharge are measured by optical emission spectroscopy and Langmuir probe under several...... operating conditions. Analysis of particle fluxes and removal rates measurements illustrates the role of ion bombardment associated with O radicals, governing the removal rates of organic matter. Auxiliary role of hydroxyl radicals is discussed on the basis of experimental data. The advantages of a water...

  10. Retrieving mesospheric water vapour from observations of volume scattering radiances

    Directory of Open Access Journals (Sweden)

    P. Vergados

    2009-02-01

    Full Text Available This study examines the possibility for a theoretical approach in the estimation of water vapour mixing ratios in the vicinity of polar mesospheric clouds (PMC using satellite observations of Volume Scattering Radiances (VSR obtained at the wavelength of 553 nm. The PMC scattering properties perturb the underlying molecular Rayleigh scattered solar radiance of the background atmosphere. As a result, the presence of PMC leads to an enhancement in the observed VSR at the altitude of the layer; the PMC VSRs are superimposed on the exponentially decreasing with height Rayleigh VSR, of the PMC-free atmosphere. The ratio between the observed and the Rayleigh VSR of the background atmosphere is used to simulate the environment in which the cloud layer is formed. In addition, a microphysical model of ice particle formation is employed to predict the PMC VSRs. The initial water vapour profile is perturbed until the modelled VSRs match the observed, at which point the corresponding temperature and water vapour profiles can be considered as a first approximation of those describing the atmosphere at the time of the observations. The role of temperature and water vapour in the cloud formation is examined by a number of sensitivity tests suggesting that the water vapour plays a dominant role in the cloud formation in agreement with experimental results. The estimated water vapour profiles are compared with independent observations to examine the model capability in the context of this study. The results obtained are in a good agreement at the peak of the PMC layer although the radiance rapidly decreases with height below the peak. This simplified scenario indicates that the technique employed can give a first approximation estimate of the water vapour mixing ratio, giving rise to the VSR observed in the presence of PMC.

  11. Atomic origins of water-vapour-promoted alloy oxidation.

    Science.gov (United States)

    Luo, Langli; Su, Mao; Yan, Pengfei; Zou, Lianfeng; Schreiber, Daniel K; Baer, Donald R; Zhu, Zihua; Zhou, Guangwen; Wang, Yanting; Bruemmer, Stephen M; Xu, Zhijie; Wang, Chongmin

    2018-05-07

    The presence of water vapour, intentional or unavoidable, is crucial to many materials applications, such as in steam generators, turbine engines, fuel cells, catalysts and corrosion 1-4 . Phenomenologically, water vapour has been noted to accelerate oxidation of metals and alloys 5,6 . However, the atomistic mechanisms behind such oxidation remain elusive. Through direct in situ atomic-scale transmission electron microscopy observations and density functional theory calculations, we reveal that water-vapour-enhanced oxidation of a nickel-chromium alloy is associated with proton-dissolution-promoted formation, migration, and clustering of both cation and anion vacancies. Protons derived from water dissociation can occupy interstitial positions in the oxide lattice, consequently lowering vacancy formation energy and decreasing the diffusion barrier of both cations and anions, which leads to enhanced oxidation in moist environments at elevated temperatures. This work provides insights into water-vapour-enhanced alloy oxidation and has significant implications in other material and chemical processes involving water vapour, such as corrosion, heterogeneous catalysis and ionic conduction.

  12. Intercomparison of TCCON and MUSICA Water Vapour Products

    Science.gov (United States)

    Weaver, D.; Strong, K.; Deutscher, N. M.; Schneider, M.; Blumenstock, T.; Robinson, J.; Notholt, J.; Sherlock, V.; Griffith, D. W. T.; Barthlott, S.; García, O. E.; Smale, D.; Palm, M.; Jones, N. B.; Hase, F.; Kivi, R.; Ramos, Y. G.; Yoshimura, K.; Sepúlveda, E.; Gómez-Peláez, Á. J.; Gisi, M.; Kohlhepp, R.; Warneke, T.; Dohe, S.; Wiegele, A.; Christner, E.; Lejeune, B.; Demoulin, P.

    2014-12-01

    We present an intercomparison between the water vapour products from the Total Carbon Column Observing Network (TCCON) and the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA), two datasets from ground-based Fourier Transform InfraRed (FTIR) spectrometers with good global representation. Where possible, comparisons to radiosondes are also included. The near-infrared TCCON measurements are optimized to provide precise monitoring of greenhouse gases for carbon cycle studies; however, TCCON's retrievals also produce water vapour products. The mid-infrared MUSICA products result from retrievals optimized to give precise and accurate information about H2O, HDO, and δD. The MUSICA water vapour products have been validated by extensive intercomparisons with H2O and δD in-situ measurements made from ground, radiosonde, and aircraft (Schneider et al. 2012, 2014), as well as by intercomparisons with satellite-based H2O and δD remote sensing measurements (Wiegele et al., 2014). This dataset provides a valuable reference point for other measurements of water vapour. This study is motivated by the limited intercomparisons performed for TCCON water vapour products and limited characterisation of their uncertainties. We compare MUSICA and TCCON products to assess the potential for TCCON measurements to contribute to studies of the water cycle, water vapour's role in climate and use as a tracer for atmospheric dynamics, and to evaluate the performance of climate models. The TCCON and MUSICA products result from measurements taken using the same FTIR instruments, enabling a comparison with constant instrumentation. The retrieval techniques differ, however, in their method and a priori information. We assess the impact of these differences and characterize the comparability of the TCCON and MUSICA datasets.

  13. Diffusion and flow of water vapours in chromatographic Alumina gel

    International Nuclear Information System (INIS)

    Khan, M.; Shah, H. U.

    2005-01-01

    The kinetics of sorption of water vapours in chromatographic alumina gel was studied. Water vapours are adsorbed on the gel at temperature (15 degree C) at different constant relative pressure from 0.1-0.93 p/p. Rate constant, Effective diffusivities, Knudsen diffusivities and bulk diffusivities were determined through Fick type equation. Total pore volume is 0.498 cc g-1 and specific surface area comes to be 465 m2 g-1 as obtained by Gurvitsch rule and Kieselve's quantities respectively. An average pore radius (hydraulic) is 1.1x10/sub -7/ cm. The study of these quantities provide a strong basis for evaluating surface properties. (author)

  14. Water vapour and carbon dioxide decrease nitric oxide readings

    NARCIS (Netherlands)

    vanderMark, TW; Kort, E; Meijer, RJ; Postma, DS; Koeter, GH

    Measurement of nitric oxide levels in exhaled ah-is commonly performed using a chemiluminescence detector. However, water vapour and carbon dioxide affect the chemiluminescence process, The influence of these gases at the concentrations present in exhaled air has not vet been studied. For this in

  15. Impact of major volcanic eruptions on stratospheric water vapour

    Directory of Open Access Journals (Sweden)

    M. Löffler

    2016-05-01

    Full Text Available Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry–climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg – Modular Earth Submodel System (ECHAM/MESSy Atmospheric Chemistry (EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño–Southern Oscillation (ENSO are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

  16. Precipitation scavenging of tritiated water vapour (HTO)

    International Nuclear Information System (INIS)

    Ogram, G.L.

    1985-10-01

    Precipitation scavenging (or washout) is an important mechanism for the removal of HTO from the atmosphere. Methods of parameterizing the depletion of a plume of HTO released to the atmosphere are examined. Simple approaches, commonly used for atmospheric transport modelling purposes, such as the use of a constant washout coefficient or washout ratio, or the use of parameters based on equilibrium assumptions, are often not justified. It is shown that these parameters depend strongly on ambient temperature and plume dimensions, as well as rainfall rate. An approximate expression for washout ratio, as a function of these variables, is developed, and it is shown that near equilibrium washout conditions are only expected to hold at long plume travel distances. A possible method of treating scavenging by snow is also suggested

  17. Modified rotating biological contactor for removal of dichloromethane vapours.

    Science.gov (United States)

    Ravi, R; Philip, Ligy; Swaminathan, T

    2015-01-01

    Bioreactors are used for the treatment of waste gas and odour that has gained much acceptance in the recent years to treat volatile organic compounds (VOCs). The different types of bioreactors (biofilter, biotrickling filter and bioscrubber) have been used for waste gas treatment. Each of these reactors has some advantages and some limitations. Though biodegradation is the main process for the removal of the pollutants, the mechanisms of removal and the microbial communities may differ among these bioreactors. Consequently, their performance or removal efficiency may also be different. Clogging of reactor and pressure drop are the main problems. In this study attempts are made to use the principle of rotating biological contactor (RBC) used for wastewater treatment for the removal of VOC. To overcome the above problem the RBC is modified which is suitable for the treatment of VOC (dichloromethane, DCM). DCM is harmful to human health and hazardous to the atmospheric environment. Modified RBC had no clogging problems and no pressure drop. So, it can handle the pollutant load for a longer period of time. A maximum elimination capacity of 25.7 g/m3 h has been achieved in this study for the DCM inlet load of 58 g/m3 h. The average biofilm thickness is 1 mm. The transient behaviour of the modified RBC treating DCM was investigated. The modified RBC is able to handle shutdown, restart and shock loading operations.

  18. A miniature discriminating monitor for tritiated water vapour

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, R.A.H.; Ravazzani, A.; Pacenti, P. [European Commission, JRC, Institute for Advanced Material, Ispra, Vatican City State, Holy See (Italy); Campi, F. [Nuclear Engineering Dept., Polytechnic of Milan (Italy)

    1998-07-01

    In detecting tritium in air (or other gas) for worker safety, it is important to discriminate between tritiated water vapour and elemental tritium, because the first is much more easily absorbed in the lungs. We haveinvented (patent pending) an innovative discriminating monitor which works better than existing designs, and is much smaller. The air (or other sample gas) passes over a large surface area of solid scintillator, which is surface-treated to make it hygroscopic. Tritiated water vapour in the air exchanges continuously, rapidly and reversibly with the water in the thin hygroscopic layer; which is of the order of 1 micron thick. The beta-emissions from tritium in the hygroscopic layer hit the solid scintillator, causing flashes of light that are detected by a photomultiplier. The new discriminating monitor for tritiated species in air offers superior performance to existing discriminating monitors, and is much smaller. It is planned to develop a portable version which could serve as a personal tritium monitor. (authors)

  19. Study of water vapour adsorption kinetics on aluminium oxide materials

    Science.gov (United States)

    Livanova, Alesya; Meshcheryakov, Evgeniy; Reshetnikov, Sergey; Kurzina, Irina

    2017-11-01

    Adsorbents on the basis of active aluminum oxide are still of demand on the adsorbent-driers market. Despite comprehensive research of alumina adsorbents, and currently is an urgent task to improve their various characteristics, and especially the task of increasing the sorption capacity. In the present work kinetics of the processes of water vapours' adsorption at room temperature on the surface of desiccant samples has been studied. It was obtained on the basis of bayerite and pseudoboehmite experimentally. The samples of pseudoboehmite modified with sodium and potassium ions were taken as study objects. The influence of an adsorbent's grain size on the kinetics of water vapours' adsorption was studied. The 0.125-0.25 mm and 0.5-1.0 mm fractions of this sample were used. It has been revealed that the saturation water vapor fine powder (0.125-0.25 mm) is almost twofold faster in comparison with the sample of fraction 0.5-1.0 mm due to the decrease in diffusion resistance in the pores of the samples when moving from the sample of larger fraction to the fine-dispersed sample. It has been established that the adsorption capacity of the pseudoboehmite samples, modified by alkaline ions, is higher by ˜40 %, than for the original samples on the basis of bayerite and pseudoboehmite.

  20. Thermally decarboxylated sodium bicarbonate: Interactions with water vapour, calorimetric study

    Directory of Open Access Journals (Sweden)

    Natalia Volkova

    2013-06-01

    Full Text Available Isothermal titration calorimetry (ITC was used to study interactions between water vapour and the surface of thermally converted sodium bicarbonate (NaHCO3. The decarboxylation degree of the samples was varied from 3% to 35% and the humidity range was 54–100%. The obtained enthalpy values were all exothermic and showed a positive linear correlation with decarboxylation degrees for each humidity studied. The critical humidity, 75% (RHo, was determined as the inflection point on a plot of the mean−ΔHkJ/mole Na2CO3 against RH. Humidities above the critical humidity lead to complete surface dissolution. The water uptake (m was determined after each calorimetric experiment, complementing the enthalpy data. A mechanism of water vapour interaction with decarboxylated samples, including the formation of trona and Wegscheider’s salt on the bicarbonate surface is proposed for humidities below RHo. Keywords: Isothermal titration calorimetry, Sodium bicarbonate, Sodium carbonate, Trona salt, Wegscheider’s salt, Enthalpy, Relative humidity, Pyrolytic decarboxylation

  1. The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

    Science.gov (United States)

    Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

    2014-01-01

    We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

  2. Multiscale network model for simulating liquid water and water vapour transfer properties of porous materials

    NARCIS (Netherlands)

    Carmeliet, J.; Descamps, F.; Houvenaghel, G.

    1999-01-01

    A multiscale network model is presented to model unsaturated moisture transfer in hygroscopic capillary-porous materials showing a broad pore-size distribution. Both capillary effects and water sorption phenomena, water vapour and liquid water transfer are considered. The multiscale approach is

  3. Utility of DMSP-SSM/I for integrated water vapour over the Indian seas

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging Solutions)

    Recent algorithms for Special Sensor Microwave/Imager (DMSP-SSM/I) satellite data are used for estimating integrated water vapour over the Indian seas. Integrated water vapour obtained from these algorithms is compared with that derived from radiosonde observations at Minicoy and Port. Blair islands. Algorithm-3 of ...

  4. Water vapour retrieval using the Precision Solar Spectroradiometer

    Science.gov (United States)

    Raptis, Panagiotis-Ioannis; Kazadzis, Stelios; Gröbner, Julian; Kouremeti, Natalia; Doppler, Lionel; Becker, Ralf; Helmis, Constantinos

    2018-02-01

    The Precision Solar Spectroradiometer (PSR) is a new spectroradiometer developed at Physikalisch-Meteorologisches Observatorium Davos - World Radiation Center (PMOD-WRC), Davos, measuring direct solar irradiance at the surface, in the 300-1020 nm spectral range and at high temporal resolution. The purpose of this work is to investigate the instrument's potential to retrieve integrated water vapour (IWV) using its spectral measurements. Two different approaches were developed in order to retrieve IWV: the first one uses single-channel and wavelength measurements, following a theoretical water vapour high absorption wavelength, and the second one uses direct sun irradiance integrated at a certain spectral region. IWV results have been validated using a 2-year data set, consisting of an AERONET sun-photometer Cimel CE318, a Global Positioning System (GPS), a microwave radiometer profiler (MWP) and radiosonde retrievals recorded at Meteorological Observatorium Lindenberg, Germany. For the monochromatic approach, better agreement with retrievals from other methods and instruments was achieved using the 946 nm channel, while for the spectral approach the 934-948 nm window was used. Compared to other instruments' retrievals, the monochromatic approach leads to mean relative differences up to 3.3 % with the coefficient of determination (R2) being in the region of 0.87-0.95, while for the spectral approach mean relative differences up to 0.7 % were recorded with R2 in the region of 0.96-0.98. Uncertainties related to IWV retrieval methods were investigated and found to be less than 0.28 cm for both methods. Absolute IWV deviations of differences between PSR and other instruments were determined the range of 0.08-0.30 cm and only in extreme cases would reach up to 15 %.

  5. Mixed garnet laser crystals for water vapour DIAL transmitter

    Science.gov (United States)

    Treichel, Rainer; Czeranowsky, Christoph; Ileri, Bilge; Petermann, Klaus; Huber, Günter

    2017-11-01

    There are more or less well established technologies such as the optical-parametric-oscillator (OPO), the Raman-laser, and the Ti-Sapphire laser, which are able to emit laser light in the region of the water vapour absorption lines. For WALES the regions of about 935 nm, 942 nm, and 944 nm have been identified as the most suitable wavelength ranges. However, each of these laser designs is highly sophisticated. Current baseline for WALES is the Ti-Sapphire laser. A fourth possibility to achieve these wavelength ranges is to shift the groundstate laser lines (938 nm and 946 nm) of the Nd:YAG laser by replacing Aluminium and Yttrium by other rare earth elements. Changes of the host lattice characteristics lead to a shift of the upper and lower laser levels. These modified crystals are summarized under the name of "Mixed Garnet" crystals. Only the Mixed Garnet lasers can be pumped directly with diode laser and use a direct approach to generate the required laser pulses without frequency conversion. Therefore no additional non-linear crystals are needed and a higher electric to optical efficiency is expected as well as single frequency operation using spectral tuning elements like etalons. Such lasers have the great potential to fulfil the requirements and to become the preferred transmitter concept for WALES as well as for follow up missions. Within a ESA study several crystal compositions have been grown, spectrally characterised and analysed. Absorbed space radiation energy in the crystal lattice causes colour centres, which can reabsorb the pump and laser wavelength and consequently reduce the laser gain considerably. Co-dopants such as Chromium and Cerium are able to suppress the colour centres and are candidates for effective radiation hardening. The results of the crystal tuning, the co-doping with different radiation hardeners and the radiation tests will be presented. There applicability for a space based water vapour DIAL transmitter will be discussed.

  6. Adsorption Of Water And Benzene Vapour In Mesoporous Materials

    Directory of Open Access Journals (Sweden)

    Paulina Taba

    2008-11-01

    Full Text Available Mesoporous materials have attracted the attention of many researchers due to the potential applications promised by the materials. This article discusses adsorption of water and benzene vapour in mesoporous materials (mesoporous silica: MCM-41, MCM-48 and their modification. MCM-41 and MCM-48 were synthesized hydrothermally at 100 oC using cethyltrimethylammonium chloride or dodecyltrimethylammonium bromide for MCM-41 (C16 or MCM-41 (C12 respectively and a mixture of cethyltrimethylammonium bromide and Triton X-100 for MCM-48 as templates. Their modifications were conducted by silylation of MCM-41 (C16 and MCM-48 with trimethylchloro silane (MCM16-TMCS and MCM48-TMCS and t-butyldimethylchloro silane (MCM16-TBDMCS and MCM48-TBDMCS. Results showed that MCM-41 and MCM-48 materials had hydrophobic features which were shown in the small amount of water adsorption at low P/P0. The hydrophobicity of samples used in this study decrease in the sequence: MCM-41 (C16 > MCM-48 > MCM-41 (C12. The hydrophobicity increased when MCM-41 and MCM-48 were silylated with TMCS or TBDMCS. All unsilylated MCM materials show higher affinity to benzene at low P/P0 than the silylated samples. The results of water and benzene adsorption showed that silylated samples are promising candidates as selective adsorbents for organic compounds.

  7. Seasonally-Active Water on Mars: Vapour, Ice, Adsorbate, and the Possibility of Liquid

    Science.gov (United States)

    Richardson, M. I.

    2002-12-01

    Seasonally-active water can be defined to include any water reservoir that communicates with other reservoirs on time scales of a year or shorter. It is the interaction of these water reservoirs, under the influence of varying solar radiation and in conjunction with surface and atmospheric temperatures, that determines the phase-stability field for water at the surface, and the distribution of water in various forms below, on, and above the surface. The atmosphere is the critical, dynamical link in this cycling system, and also (fortunately) one of the easiest to observe. Viking and Mars Global Surveyor observations paint a strongly asymmetric picture of the global seasonal water cycle, tied proximately to planetary eccentricity, and the existence of residual ice caps of different composition at the two poles. The northern summer experiences the largest water vapour columns, and is associated with sublimation from the northern residual water ice cap. The southern summer residual carbon dioxide ice cap is cold trap for water. Asymmetry in the water cycle is an unsolved problem. Possible solutions may involve the current timing of perihelion (the water cap resides at the pole experiencing the longer but cooler summer), the trapping of water ice in the northern hemisphere by tropical water ice clouds, and the bias in the annual-average, zonal-mean atmospheric circulation resulting from the zonal-mean difference in the elevation of the northern and southern hemispheres. Adsorbed and frozen water have proven harder to constrain. Recent Odyssey Gamma Ray Spectrometer results suggest substantial ground ice in the mid- and high-latitudes, but this water is likely below the seasonal skin depth for two reasons: the GRS results are best fit with such a model, and GCM models of the water cycle produce dramatically unrealistic atmospheric vapour distributions when such a very near surface, GRS-like distribution is initialized - ultimately removing the water to the northern and

  8. Vapour and air bubble collapse analysis in viscous compressible water

    Directory of Open Access Journals (Sweden)

    Gil Bazanini

    2001-01-01

    Full Text Available Numerical simulations of the collapse of bubbles (or cavities are shown, using the finite difference method, taking into account the compressibility of the liquid, expected to occur in the final stages of the collapse process. Results are compared with experimental and theoretical data for incompressible liquids, to see the influence of the compressibility of the water in the bubble collapse. Pressure fields values are calculated in an area of 800 x 800 mm, for the case of one bubble under the hypothesis of spherical symmetry. Results are shown as radius versus time curves for the collapse (to compare collapse times, and pressure curves in the plane, for pressure fields. Such calculations are new because of their general point of view, since the existing works do not take into account the existence of vapour in the bubble, neither show the pressure fields seen here. It is also expected to see the influence of the compressibility of the water in the collapse time, and in the pressure field, when comparing pressure values.

  9. Modelling water vapour permeability through atomic layer deposition coated photovoltaic barrier defects

    Energy Technology Data Exchange (ETDEWEB)

    Elrawemi, Mohamed, E-mail: Mohamed.elrawemi@hud.ac.uk [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Blunt, Liam; Fleming, Leigh [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Bird, David, E-mail: David.Bird@uk-cpi.com [Centre for Process Innovation Limited, Sedgefield, County Durham (United Kingdom); Robbins, David [Centre for Process Innovation Limited, Sedgefield, County Durham (United Kingdom); Sweeney, Francis [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom)

    2014-11-03

    Transparent barrier films such as Al{sub 2}O{sub 3} used for prevention of oxygen and/or water vapour permeation are the subject of increasing research interest when used for the encapsulation of flexible photovoltaic modules. However, the existence of micro-scale defects in the barrier surface topography has been shown to have the potential to facilitate water vapour ingress, thereby reducing cell efficiency and causing internal electrical shorts. Previous work has shown that small defects (≤ 3 μm lateral dimension) were less significant in determining water vapour ingress. In contrast, larger defects (≥ 3 μm lateral dimension) seem to be more detrimental to the barrier functionality. Experimental results based on surface topography segmentation analysis and a model presented in this paper will be used to test the hypothesis that the major contributing defects to water vapour transmission rate are small numbers of large defects. The model highlighted in this study has the potential to be used for gaining a better understanding of photovoltaic module efficiency and performance. - Highlights: • A model of water vapour permeation through barrier defects is presented. • The effect of the defects on the water vapour permeability is investigated. • Defect density correlates with water vapour permeability. • Large defects may dominate the permeation properties of the barrier film.

  10. WAVE-E: The WAter Vapour European-Explorer Mission

    Science.gov (United States)

    Jimenez-LLuva, David; Deiml, Michael; Pavesi, Sara

    2017-04-01

    In the last decade, stratosphere-troposphere coupling processes in the Upper Troposphere Lower Stratosphere (UTLS) have been increasingly recognized to severely impact surface climate and high-impact weather phenomena. Weakened stratospheric circumpolar jets have been linked to worldwide extreme temperature and high-precipitation events, while anomalously strong stratospheric jets can lead to an increase in surface winds and tropical cyclone intensity. Moreover, stratospheric water vapor has been identified as an important forcing for global decadal surface climate change. In the past years, operational weather forecast and climate models have adapted a high vertical resolution in the UTLS region in order to capture the dynamical processes occurring in this highly stratified region. However, there is an evident lack of available measurements in the UTLS region to consistently support these models and further improve process understanding. Consequently, both the IPCC fifth assessment report and the ESA-GEWEX report 'Earth Observation and Water Cycle Science Priorities' have identified an urgent need for long-term observations and improved process understanding in the UTLS region. To close this gap, the authors propose the 'WAter Vapour European - Explorer' (WAVE-E) space mission, whose primary goal is to monitor water vapor in the UTLS at 1 km vertical, 25 km horizontal and sub-daily temporal resolution. WAVE-E consists of three quasi-identical small ( 500 kg) satellites (WAVE-E 1-3) in a constellation of Sun-Synchronous Low Earth Orbits, each carrying a limb sounding and cross-track scanning mid-infrared passive spectrometer (824 cm-1 to 829 cm-1). The core of the instruments builds a monolithic, field-widened type of Michelson interferometer without any moving parts, rendering it rigid and fault tolerant. Synergistic use of WAVE-E and MetOp-NG operational satellites is identified, such that a data fusion algorithm could provide water vapour profiles from the

  11. Thermalisation of high energy electrons and positrons in water vapour

    Science.gov (United States)

    Munoz, A.; Blanco, F.; Limao-Vieira, P.; Thorn, P. A.; Brunger, M. J.; Buckman, S. J.; Garcia, G.

    2008-07-01

    In this study we describe a method to simulate single electron tracks of electrons in molecular gases, particularly in water vapour, from relatively high energies, where Born (Inokuti 1971) approximation is supposed to be valid, down to thermal energies paying special attention to the low energy secondary electrons which are abundantly generated along the energy degradation procedure. Experimental electron scattering cross sections (Munoz et al. 2007) and energy loss spectra (Thorn et al. 2007) have been determined, where possible, to be used as input parameters of the simulating program. These experimental data have been complemented with optical potential calculation (Blanco and Garcia 2003) providing a complete set of interaction probability functions for each type of collision which could take place in the considered energy range: elastic, ionization, electronic excitation, vibrational and rotational excitation. From the simulated track structure (Munoz et al. 2005) information about energy deposition and radiation damage at the molecular level can be derived. A similar procedure is proposed to the study of single positron tracks in gases. Due to the lack of experimental data for positron interaction with molecules, especially for those related to energy loss and excitation cross sections, some distribution probability data have been derived from those of electron scattering by introducing positron characteristics as positroniun formation. Preliminary results for argon are presented discussing also the utility of the model to biomedical applications based on positron emitters.

  12. Water vapour and ozone profiles in the midlatitude upper troposphere

    Directory of Open Access Journals (Sweden)

    G. Vaughan

    2005-01-01

    Full Text Available We present an investigation of upper tropospheric humidity profiles measured with a standard radiosonde, the Vaisala RS80-A, and a commercial frost-point hygrometer, the Snow White. Modifications to the Snow White, to enable the mirror reflectivity and Peltier cooling current to be monitored during flight, were found to be necessary to determine when the instrument was functioning correctly; a further modification to prevent hydrometeors entering the inlet was also implemented. From 23 combined flights of an ozonesonde, radiosonde and Snow White between September 2001 and July 2002, clear agreement was found between the two humidity sensors, with a mean difference of <2% in relative humidity from 2 to 10km, and 2.2% between 10 and 13km. This agreement required a correction to the radiosonde humidity, as described by Miloshevich et al. (2001. Using this result, the dataset of 324 ozonesonde/RS80-A profiles measured from Aberystwyth between 1991 and 2002 was examined to derive statistics for the distribution of water vapour and ozone. Supersaturation with respect to ice was frequently seen at the higher levels - 24% of the time in winter between 8 and 10km. The fairly uniform distribution of relative humidity persisted to 120% in winter, but decreased rapidly above 100% in summer.

  13. Removing water from gels

    International Nuclear Information System (INIS)

    Lane, E.S.; Winter, J.A.

    1982-01-01

    Water is removed from a gel material by contacting the gel material with an organic liquid and contacting the organic liquid with a gas such that water is taken up by the gas. The invention, in one embodiment, may be used to dry gel materials whilst maintaining an open porous network therein. In one example, the invention is applied to gel precipitated spheres containing uranium and plutonium. (author)

  14. Measurement of water vapour transport through a porous non-hygroscopic material in a temperature gradient

    DEFF Research Database (Denmark)

    Hansen, Thor; Padfield, Tim; Hansen, Kurt Kielsgaard

    2014-01-01

    This was an experiment to identify the driving potential for water vapour diffusion through porous materials in a temperature gradient. The specimen of mineral fibre insulation was placed between a space with controlled temperature and relative humidity and a space with a controlled, higher...... temperature, and a measured but not controlled relative humidity (RH). This assembly was allowed to reach equilibrium with no vapour movement between the spaces, as tested by a constant RH on each side and by zero flux of water vapour measured in the cold side chamber. The RH and temperature values were...

  15. The thermotidal exciting function for water vapour absorption of solar radiation

    Directory of Open Access Journals (Sweden)

    M. BONAFEDE

    1976-06-01

    Full Text Available The thermotidal exciting function J is considered, for
    the absorption of solar radiation by water vapour, according to the model
    derived by Siebert. The Mugge-Moller formula for water vapour absorption
    is integrated numerically, using experimental data for the water vapour
    concentration in the troposphere and the stratosphere. It appears that
    Siebort's formula is a reasonable approximation at low tropospheric levels
    but it dramatically overestimates the water vapour thermotidal heating
    in the upper troposphere and in the stratosphere. It seems thus possible
    that, if the correct vertical profile is employed for J , the amplitudes and
    phases of the diurnal temperature oscillations and of the tidal wind speeds
    may suffer significant changes from those previously calculated and possibly explain the three hours delay of the observed phases from the computed values.

  16. Swelling behaviour of Early Jurassic shales when exposed to water vapour

    Science.gov (United States)

    Houben, Maartje; Barnhoorn, Auke; Peach, Colin; Drury, Martyn

    2017-04-01

    The presence of water in mudrocks has a largely negative impact on production of gas, due to the fact that water causes swelling of the rock. Removing the water from the mudrock on the other hand could potentially shrink the rock and increase the matrix permeability. Investigation of the swelling/shrinkage behaviour of the rock during exposure to water vapour is of key importance in designing and optimizing unconventional production strategies. We have used outcrop samples of the Whitby Mudstone and the Posidonia shale [1], potential unconventional sources for gas in North-western Europe, to measure the swelling and shrinkage behaviour. Subsamples, 1 mm cubes, were prepared by the Glass Workshop at Utrecht University using a high precision digitally controlled diamond wafering saw cooled by air. The mm cubes were then exposed to atmospheres with different relative humidities either in an Environmental Scanning Electron Microscope (ESEM) or in a 3D dilatometer. So that the sample responses to exposure of water vapour could be measured. Parallel to the bedding we found a swelling strain between 0.5 and 1.5 %, perpendicular to the bedding though swelling strain varied between 1 and 3.5%. Volumetric swelling strain varied between 1 and 2% at a maximum relative humidity of 95%. Volumetric swelling strains measured in the Early Toarcian Shales are similar to the ones found in coal [2], where the results suggest that it might be possible to increase permeability in the reservoir by decreasing the in-situ water activity due to shrinkage of the matrix. [1] M.E. Houben, A. Barnhoorn, L. Wasch, J. Trabucho-Alexandre, C. J. Peach, M.R. Drury (2016). Microstructures of Early Jurassic (Toarcian) shales of Northern Europe, International Journal of Coal Geology, 165, 76-89. [2] Jinfeng Liu, Colin J. Peach, Christopher J. Spiers (2016). Anisotropic swelling behaviour of coal matrix cubes exposed to water vapour: Effects of relative humidity and sample size, International Journal of

  17. Venera 15: Water vapour in the middle atmosphere of Venus

    Science.gov (United States)

    Ignatiev, N. I.; Moroz, V. I.; Zasova, L. V.; Khatuntsev, I. V.

    1999-01-01

    In 1983, spectra of Venus in the region of 6-40 μm were measured by means of the Fourier Spectrometer aboard the Venera 15 orbiter. It covered local solar times from 4 a.m. to 10 a.m. and from 4 p.m. to 10 p.m. in the latitude range from -65° up to 87°. The results of an extended processing and analysis of these data are presented. Time and spatial variations of the water vapour were found. Most of the measurements fall in the range of 5-15 ppm, which is close to the early results. The effective altitude of sounding is approximately equal to the altitude where the optical depth τ = 1. Two latitude regions can be distinguished: (A) 20° 60°, which are characterised by different altitudes of the level of τ = 1: 62 and 55 km respectively. Mean mixing ratios near this level in the two regions are almost the same, but the partial pressures and mass densities in region (B) are 2-4 times greater than those in region (A). In region (A) a weak dayside maximum and a nightside minimum were observed. Region (B) is of inhomogeneous structure, and the retrieved mixing ratio has greater uncertainty and may probably change from the detection limit of 1 ppm up to 30 ppm. Although the retrieval of H2O mixing ratio altitude profile from the Venera 15 data appeared to be impossible, indirect indications were found that at least in region (A) the mixing ratio decreases with altitude.

  18. The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding

    Energy Technology Data Exchange (ETDEWEB)

    N' Dri Koffi, Ernest; Maetzler, Christian [Bern Univ. (Switzerland). Inst. of Applied Physics; Graham, Edward [Bern Univ. (Switzerland). Inst. of Applied Physics; University of the Highlands and Islands, Stornoway, Scotland (United Kingdom). Lews Castle College

    2013-10-15

    The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the 'Swiss box') to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 x 10{sup 7} kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the Swiss box 'import' more water vapour than it 'exports', but the amount gained remains only a small fraction (1% to 5%) of the total available water vapour passing by. High inward water vapour fluxes are not necessarily linked to high precipitation episodes. The water vapour flux during the August 2005 floods, which caused severe damage in central Switzerland, is examined and an assessment is made of the computed water vapour fluxes compared to high spatio-temporal rain gauge and radar observations. About 25% of the incoming water vapour flux was stored in Switzerland. The computed water vapour fluxes from ECMWF data compare well with the mean rain gauge observations and the combined rain-gauge radar precipitation products. (orig.)

  19. The millennium water vapour drop in chemistry–climate model simulations

    Directory of Open Access Journals (Sweden)

    S. Brinkop

    2016-07-01

    Full Text Available This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop" and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM EMAC (ECHAM/MESSy Atmospheric Chemistry Model. The model simulations differ with respect to the prescribed sea surface temperatures (SSTs and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer–Dobson circulation (BDC. We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST changes due to a coincidence with a preceding strong El Niño–Southern Oscillation event (1997/1998 followed by a strong La Niña event (1999/2000 and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO in 2000. Correct (observed SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics

  20. Sampling system of atmospheric water vapour for analysis of the γ sub(D) relationship

    International Nuclear Information System (INIS)

    Foloni, L.L.; Villa Nova, N.A.; Salati, E.

    1979-01-01

    The development of a system to water vapour air, for natural isotopic composition analysis of hydrogen is presented. The system uses molecular sieve, type '4A', without cooling agent and permits the choice of a sampling time, variyng from a few minutes to many hours, through the control of the admission of vapour flux. The system has good performance in field conditions, with errors of the order of + -3,0 0 /00 in the γ sub(D)( 0 /00) measurements [pt

  1. Water vapour and methane coupling in the stratosphere observed using SCIAMACHY solar occultation measurements

    Directory of Open Access Journals (Sweden)

    S. Noël

    2018-04-01

    Full Text Available An improved stratospheric water vapour data set has been retrieved from SCIAMACHY/ENVISAT solar occultation measurements. It is similar to that successfully applied to methane and carbon dioxide. There is now a consistent set of data products for the three constituents covering the altitudes 17–45 km, the latitude range between about 50 and 70° N, and the period August 2002 to April 2012. The new water vapour concentration profiles agree with collocated results from ACE-FTS and MLS/Aura to within  ∼  5 %. A significant positive linear change in water vapour for the time 2003–2011 is observed at lower stratospheric altitudes with a value of about 0.015 ± 0.008 ppmv year−1 around 17 km. Between 30 and 37 km the changes become significantly negative (about −0.01 ± 0.008 ppmv year−1; all errors are 2σ values. The combined analysis of the SCIAMACHY methane and water vapour time series shows the expected anti-correlation between stratospheric methane and water vapour and a clear temporal variation related to the Quasi-Biennial Oscillation (QBO. Above about 20 km most of the additional water vapour is attributed to the oxidation of methane. In addition short-term fluctuations and longer-term variations on a timescale of 5–6 years are observed. The SCIAMACHY data confirm that at lower altitudes the amount of water vapour and methane are transported from the tropics to higher latitudes via the shallow branch of the Brewer–Dobson circulation.

  2. Continuous measurements of isotopic composition of water vapour on the East Antarctic Plateau

    Directory of Open Access Journals (Sweden)

    M. Casado

    2016-07-01

    Full Text Available Water stable isotopes in central Antarctic ice cores are critical to quantify past temperature changes. Accurate temperature reconstructions require one to understand the processes controlling surface snow isotopic composition. Isotopic fractionation processes occurring in the atmosphere and controlling snowfall isotopic composition are well understood theoretically and implemented in atmospheric models. However, post-deposition processes are poorly documented and understood. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum between surface water vapour, precipitation, surface snow and buried snow. Here, we target the isotopic composition of water vapour at Concordia Station, where the oldest EPICA Dome C ice cores have been retrieved. While snowfall and surface snow sampling is routinely performed, accurate measurements of surface water vapour are challenging in such cold and dry conditions. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces. Two infrared spectrometers have been deployed at Concordia, allowing continuous, in situ measurements for 1 month in December 2014–January 2015. Comparison of the results from infrared spectroscopy with laboratory measurements of discrete samples trapped using cryogenic sampling validates the relevance of the method to measure isotopic composition in dry conditions. We observe very large diurnal cycles in isotopic composition well correlated with temperature diurnal cycles. Identification of different behaviours of isotopic composition in the water vapour associated with turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction. Even if the vapour isotopic composition seems to be, at least part of the time, at equilibrium with the local snow, the slope of δD against δ18O prevents us from identifying

  3. Dew-point measurements at high water vapour pressure

    Science.gov (United States)

    Lomperski, S.; Dreier, J.

    1996-05-01

    A dew-point meter capable of measuring humidity at high vapour pressure and high temperature has been constructed and tested. Humidity measurements in pure steam were made over the temperature range 100 - 1500957-0233/7/5/003/img1C and a vapour pressure range of 1 - 4 bar. The dew-point meter performance was assessed by comparing measurements with a pressure transmitter and agreement between the two was within 0957-0233/7/5/003/img2% relative humidity. Humidity measurements in steam - air mixtures were also made and the dew-point meter readings were compared to those of a zirconia oxygen sensor. For these tests the dew-point meter readings were generally within 0957-0233/7/5/003/img2% relative humidity of the oxygen sensor measurements.

  4. Steam/water separation device for drying a wet vapour

    International Nuclear Information System (INIS)

    Sundheimer, P.

    1986-01-01

    The aim of the present invention is to dry a wet vapour which flows up to the device. The device has at least a group of steam dryer elements in a zone in which there is a vertical apertured panel; this vertical apertured panel is a metal grille with baffles the inlet steam flow to make it horizontal or slightly inclined to the bottom. The invention applies more particularly, to PWR steam generators [fr

  5. A simple passive method of collecting water vapour for environmental tritium monitoring

    International Nuclear Information System (INIS)

    Iida, T.; Fukuda, H.; Ikebe, Y.; Yokoyama, S.

    1995-01-01

    To investigate the average behaviour of tritium in an atmospheric environment, it is necessary to collect water vapour in air over a long period at numerous locations. For the purpose of the study, the passive method was developed: this is handy, low-priced and could collect water vapour in air without motive power. This paper describes the characteristics of the passive collecting method, the performance of water collection in outdoor air and the measurements of tritium concentrations in water samples collected by the passive method. (author)

  6. MEDUSA: The ExoMars experiment for in-situ monitoring of dust and water vapour

    Science.gov (United States)

    Colangeli, L.; Lopez-Moreno, J. J.; Nørnberg, P.; Della Corte, V.; Esposito, F.; Mazzotta Epifani, E.; Merrison, J.; Molfese, C.; Palumbo, P.; Rodriguez-Gomez, J. F.; Rotundi, A.; Visconti, G.; Zarnecki, J. C.; The International Medusa Team

    2009-07-01

    Dust and water vapour are fundamental components of the Martian atmosphere. In view of tracing the past environmental conditions on Mars, that possibly favoured the appearing of life forms, it is important to study the present climate and its evolution. Here dust and water vapour have (and have had) strong influence. Of major scientific interest is the quantity and physical, chemical and electrical properties of dust and the abundance of water vapour dispersed in the atmosphere and their exchange with the surface. Moreover, in view of the exploration of the planet with automated systems and in the future by manned missions, it is of primary importance to analyse the hazards linked to these environmental factors. The Martian Environmental Dust Systematic Analyser (MEDUSA) experiment, included in the scientific payload of the ESA ExoMars mission, accommodates a complement of sensors, based on optical detection and cumulative mass deposition, that aims to study dust and water vapour in the lower Martian atmosphere. The goals are to study, for the first time, in-situ and quantitatively, physical properties of the airborne dust, including the cumulative dust mass flux, the dust deposition rate, the physical and electrification properties, the size distribution of sampled particles and the atmospheric water vapour abundance versus time.

  7. SPATIO-TEMPORAL ESTIMATION OF INTEGRATED WATER VAPOUR OVER THE MALAYSIAN PENINSULA DURING MONSOON SEASON

    Directory of Open Access Journals (Sweden)

    S. Salihin

    2017-10-01

    Full Text Available This paper provides the precise information on spatial-temporal distribution of water vapour that was retrieved from Zenith Path Delay (ZPD which was estimated by Global Positioning System (GPS processing over the Malaysian Peninsular. A time series analysis of these ZPD and Integrated Water Vapor (IWV values was done to capture the characteristic on their seasonal variation during monsoon seasons. This study was found that the pattern and distribution of atmospheric water vapour over Malaysian Peninsular in whole four years periods were influenced by two inter-monsoon and two monsoon seasons which are First Inter-monsoon, Second Inter-monsoon, Southwest monsoon and Northeast monsoon.

  8. Intercomparison of atmospheric water vapour measurements at a Canadian High Arctic site

    Science.gov (United States)

    Weaver, Dan; Strong, Kimberly; Schneider, Matthias; Rowe, Penny M.; Sioris, Chris; Walker, Kaley A.; Mariani, Zen; Uttal, Taneil; McElroy, C. Thomas; Vömel, Holger; Spassiani, Alessio; Drummond, James R.

    2017-08-01

    Water vapour is a critical component of the Earth system. Techniques to acquire and improve measurements of atmospheric water vapour and its isotopes are under active development. This work presents a detailed intercomparison of water vapour total column measurements taken between 2006 and 2014 at a Canadian High Arctic research site (Eureka, Nunavut). Instruments include radiosondes, sun photometers, a microwave radiometer, and emission and solar absorption Fourier transform infrared (FTIR) spectrometers. Close agreement is observed between all combination of datasets, with mean differences ≤ 1.0 kg m-2 and correlation coefficients ≥ 0.98. The one exception in the observed high correlation is the comparison between the microwave radiometer and a radiosonde product, which had a correlation coefficient of 0.92.A variety of biases affecting Eureka instruments are revealed and discussed. A subset of Eureka radiosonde measurements was processed by the Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN) for this study. Comparisons reveal a small dry bias in the standard radiosonde measurement water vapour total columns of approximately 4 %. A recently produced solar absorption FTIR spectrometer dataset resulting from the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) retrieval technique is shown to offer accurate measurements of water vapour total columns (e.g. average agreement within -5.2 % of GRUAN and -6.5 % of a co-located emission FTIR spectrometer). However, comparisons show a small wet bias of approximately 6 % at the high-latitude Eureka site. In addition, a new dataset derived from Atmospheric Emitted Radiance Interferometer (AERI) measurements is shown to provide accurate water vapour measurements (e.g. average agreement was within 4 % of GRUAN), which usefully enables measurements to be taken during day and night (especially valuable during polar night).

  9. Effect of water vapour absorption on hydroxyl temperatures measured from Svalbard

    Directory of Open Access Journals (Sweden)

    J. M. Chadney

    2017-03-01

    Full Text Available We model absorption by atmospheric water vapour of hydroxyl airglow emission using the HIgh-resolution TRANsmission molecular absorption database (HITRAN2012. Transmission coefficients are provided as a function of water vapour column density for the strongest OH Meinel emission lines in the (8–3, (5–1, (9–4, (8–4, and (6–2 vibrational bands. These coefficients are used to determine precise OH(8–3 rotational temperatures from spectra measured by the High Throughput Imaging Echelle Spectrograph (HiTIES, installed at the Kjell Henriksen Observatory (KHO, Svalbard. The method described in this paper also allows us to estimate atmospheric water vapour content using the HiTIES instrument.

  10. Distribution of tritium in water vapour and precipitation around Wolsung nuclear power plant.

    Science.gov (United States)

    Chae, Jung-Seok; Lee, Sang-Kuk; Kim, Yongjae; Lee, Jung-Min; Cho, Heung-Joon; Cho, Yong-Woo; Yun, Ju-Yong

    2011-07-01

    The distribution of tritium in water vapour and precipitation with discharge of tritiated water vapour and meteorological factors was studied around the Wolsung nuclear power plant (NPP) site during the period 2004-2008. The tritium concentrations in atmospheric water vapour and precipitation had a temporal variation with relatively high values in the early summer. Spatial distribution of tritium concentrations was affected by various factors such as distance from the NPP site, wind direction, tritium discharge into the atmosphere and atmospheric dispersion factor. The annual mean concentrations of atmospheric HTO and precipitation were correlated with the amount of gaseous tritium released from the Wolsung NPP. The tritium concentrations in precipitation decrease exponentially with an increase of the distance from the Wolsung NPP site.

  11. Discovery of water vapour in the carbon star V Cygni from observations with Herschel/HIFI

    NARCIS (Netherlands)

    Neufeld, D. A.; Gonzalez-Alfonso, E.; Melnick, G.; Pulecka, M.; Schmidt, M.; Szczerba, R.; Bujarrabal, V.; Alcolea, J.; Cernicharo, J.; Decin, L.; Dominik, C.; Justtanont, K.; de Koter, A.; Marston, A. P.; Menten, K.; Olofsson, H.; Planesas, P.; Schoier, F. L.; Teyssier, D.; Waters, L. B. F. M.; Edwards, K.; McCoey, C.; Shipman, R.; Jellema, W.; de Graauw, T.; Ossenkopf, V.; Schieder, R.; Philipp, S.

    2010-01-01

    We report the discovery of water vapour toward the carbon star V Cygni. We have used Herschel's HIFI instrument, in dual beam switch mode, to observe the 1(11)-0(00) para-water transition at 1113.3430 GHz in the upper sideband of the Band 4b receiver. The observed spectral line profile is nearly

  12. Modelling and interpreting the isotopic composition of water vapour in convective updrafts

    Directory of Open Access Journals (Sweden)

    M. Bolot

    2013-08-01

    Full Text Available The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed-phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters, including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener–Bergeron–Findeisen process. As all of these processes are related to updraft strength, particle size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

  13. Modelling and interpreting the isotopic composition of water vapour in convective updrafts

    Science.gov (United States)

    Bolot, M.; Legras, B.; Moyer, E. J.

    2013-08-01

    The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed-phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters, including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener-Bergeron-Findeisen process). As all of these processes are related to updraft strength, particle size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

  14. Modelling and intepreting the isotopic composition of water vapour in convective updrafts

    Science.gov (United States)

    Bolot, M.; Legras, B.; Moyer, E. J.

    2012-08-01

    The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener-Bergeron-Findeisen process). As all of these processes are related to updraft strength, droplet size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

  15. WATER VAPOUR PERMEABILITY PROPERTIES OF CELLULAR WOOD MATERIAL AND CONDENSATION RISK OF COMPOSITE PANEL WALLS

    Directory of Open Access Journals (Sweden)

    Janis IEJAVS

    2016-09-01

    Full Text Available Invention of light weight cellular wood material (CWM with a trade mark of Dendrolight is one of innovations in wood industry of the last decade. The aim of the research was to define the water vapour permeability properties of CWM and to analyse the condensation risk of various wall envelopes where solid wood cellular material is used. To determine the water vapour permeability of CWM, test samples were produced in the factory using routine production technology and tested according to the standard EN 12086:2014. Water vapour permeability factor (μ and other properties of six different configurations of CWM samples were determined. Using the experimental data the indicative influence of geometrical parameters such as lamella thickness, number of lamellas and material direction were investigated and evaluated. To study the condensation risk within the wall envelope containing CWM calculation method given in LVS EN ISO 13788:2012 was used. To ease the calculation process previously developed JavaScript calculation software that had only capability to calculate thermal transmittance was extended so that condensation risk in multi-layer composite walls can be analysed. Water vapour permeability factor in CWM is highly direction dependant. If parallel and perpendicular direction of CWM is compared the value of water vapour permeability factor can differentiate more than two times. Another significant factor for condensation risk analysis is overall thickness of CWM since it directly influences the equivalent air layer thickness. The influence of other factors such as lamella thickness, or groove depth is minor when water vapour permeability properties are compared. From the analysis of CWM performance in building envelope it can be concluded that uninsulated CWM panels used during winter months will pose the risk of condensation damage to structure, but the risk can be reduced or prevented if insulation layer is applied to the CWM panel wall

  16. Microwave measurements of the absolute values of absorption by water vapour in the atmosphere.

    Science.gov (United States)

    Hogg, D C; Guiraud, F O

    1979-05-31

    MEASUREMENT of the absolute value of absorption by water vapour at microwave frequencies is difficult because the effect is so small. Far in the wings of the absorption lines, in the so-called 'windows' of the spectrum, it is especially difficult to achieve high accuracy in the free atmosphere. But it is in these windows that the behaviour of the absorption is important from both applied and scientific points of view. Satellite communications, remote sensing of the atmosphere, and radioastronomy, are all influenced by this behaviour. Measurements on an Earth-space path are reported here; the results indicate a nonlinear relationship between absorption and water-vapour content.

  17. Thermal diffusion of water vapour in porous materials: fact or fiction?

    DEFF Research Database (Denmark)

    Janssen, Hans

    2011-01-01

    diffusion. Thermal diffusion opponents, on the other hand, assert that these thermal transports are negligibly small. This paper resolves that contradiction. A critical analysis of the investigations supporting the occurrence of thermal diffusion reveals that all are flawed. A correct reinterpretation...... its negligible magnitude. It can in conclusion be stated that thermal diffusion is of no importance for building science applications, leaving vapour pressure as the sole significant transport potential for the diffusion of water vapour in porous materials. (C) 2010 Elsevier Ltd. All rights reserved....

  18. Reaction of soda-lime-silica glass melt with water vapour at melting temperatures

    Czech Academy of Sciences Publication Activity Database

    Vernerová, Miroslava; Kloužek, Jaroslav; Němec, Lubomír

    2015-01-01

    Roč. 416, MAY 15 (2015), s. 21-30 ISSN 0022-3093 R&D Projects: GA TA ČR TA01010844 Institutional support: RVO:67985891 Keywords : glass melt * sulfate * water vapour * bubble nucleation * melt foaming * glass melting Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.825, year: 2015

  19. Water vapour trends at several tropospheric levels over South America between 1973 and 2003

    International Nuclear Information System (INIS)

    Morales, L.; Mattar, C.; Da-Silva, L.; Abarca, R.

    2009-01-01

    In this paper water vapour trends were analyzed at several tropospheric levels over South America between 1973 and 2003. It was carried out using in situ values retrieved by 15 radiosonde stations and NCEP NCAR Reanalysis data (NNR). NNR and radiosonde water vapour data were linked to Koeppen-Geiger climatic zones to calculate anomalies, trends, and the non-parametric statistical significance for each mandatory level. A methodology used to process radiosonde data is shown. Water vapour trends in tropical climates presented positive decadal trends. This is statistically significant for the first mandatory levels retrieved by radiosonde. The highest values are presented in average with NNR; the decadal magnitude for climate Af being 0.15 g kg -1 for 1000 and 925 h Pa, and for climate As 0.27 g kg -1 for 925 and 850 h Pa. For non-tropical climates the magnitude trends of specific humidity are affected by the spatial resolution of NNR, which is seen when comparing the results received by the radiosondes. Finally, this paper shows the initial results of water vapour content trends in the last three decades over South America. Strong climatic events and synoptic oscillations were not commented upon.

  20. Water vapour rises from the cooling towers for the ATLAS detector at Point 1

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    Electronics on the ATLAS detector produce heat when the experiment is running. An elaborate cooling system keeps the detector from overheating. On the surface, the warm water vapour that rises from the detector 100metres underground is clearly visible from the ATLAS cooling towers on the CERN Meyrin site in Switzerland.

  1. Detection of the contamination of air by tritiated water vapour around the reactor EL3

    International Nuclear Information System (INIS)

    Lebouleux, P.; Ardellier, A.; Valero, S.

    1968-01-01

    The authors describe the apparatus used for the detection of the tritiated water vapour contamination in the air around the reactor EL 3. The apparatus consists of two air-circulation ionisation chambers; the air in one of these is dried by passage through a silica-gel column. By carrying out a differential measurement of the ionization currents, it is possible to measure the tritiated water vapour concentration. A theoretical study of the response of the chambers is carried out for two types of emission of the tritiated water vapour: continuous, or in bursts. The experimental work comprises: calibration in the measurement range employed; study of the selectivity for other active gases; study of typical accidents; the interpretation of the results in the case of discontinuous emission, taking into account the desorption from the walls of the measurement chamber, a phenomenon which is observed during the emptying process. The authors give finally actual examples of how to use the results. The apparatus built makes it possible to detect, in less than ten minutes, contamination by tritiated water vapour in the presence of other active gases, in a measurement range of between 3 and 2200 MPC, and with an accuracy of about 25 per cent. A transposition to calculations of the risk to workers should be made with the utmost caution; an envelope of this risk can be drawn up more or less accurately depending on particular cases. (authors) [fr

  2. Behaviour of carbon dioxide and water vapour flux densities from a disturbed raised peat bog

    NARCIS (Netherlands)

    Nieveen, J.P.; Jacobs, A.F.G.

    2002-01-01

    Measurements of carbon dioxide and water vapour flux densities were carried out for a disturbed raised peat bog in the north of the Netherlands during an 18 month continuous experiment. Tussock grass (sp. Molinea caerulae) mainly dominated the vegetation of the bog area. The maximum leaf area index

  3. Leidenfrost vapour layer moderation of the drag crisis and trajectories of superhydrophobic and hydrophilic spheres falling in water

    KAUST Repository

    Vakarelski, Ivan Uriev; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2014-01-01

    We investigate the dynamic effects of a Leidenfrost vapour layer sustained on the surface of heated steel spheres during free fall in water. We find that a stable vapour layer sustained on the textured superhydrophobic surface of spheres falling through 95 °C water can reduce the hydrodynamic drag by up to 75% and stabilize the sphere trajectory for the Reynolds number between 104 and 106, spanning the drag crisis in the absence of the vapour layer. For hydrophilic spheres under the same conditions, the transition to drag reduction and trajectory stability occurs abruptly at a temperature different from the static Leidenfrost point. The observed drag reduction effects are attributed to the disruption of the viscous boundary layer by the vapour layer whose thickness depends on the water temperature. Both the drag reduction and the trajectory stabilization effects are expected to have significant implications for development of sustainable vapour layer based technologies. © the Partner Organisations 2014.

  4. Sorption of water vapour by the Na+-exchanged clay-sized fractions of some tropical soil samples

    International Nuclear Information System (INIS)

    Yormah, T.B.R.; Hayes, M.H.B.

    1993-09-01

    Water vapour sorption isotherms at 299K for the Na + -exchanged clay-sized (≤ 2μm e.s.d.) fraction of two sets of samples taken at three different depths from a tropical soil profile have been studied. One set of samples was treated (with H 2 O 2 ) for the removal of much of the organic matter (OM); the other set (of the same samples) was not so treated. The isotherms obtained were all of type II and analyses by the BET method yielded values for the Specific Surface Areas (SSA) and for the average energy of adsorption of the first layer of adsorbate (E a ). OM content and SSA for the untreated samples were found to decrease with depth. Whereas removal of organic matter made negligible difference to the SSA of the top/surface soil, the same treatment produced a significant increase in the SSA of the samples taken from the middle and from the lower depths in the profile; the resulting increase was more pronounced for the subsoil. It has been deduced from these results that OM in the surface soil was less involved with the inorganic soil colloids than that in the subsoil. The increase in surface area which resulted from the removal of OM from the subsoil was most probably due to disaggregation. Values of E a obtained show that for all the samples the adsorption of water vapour became more energetic after the oxidative removal of organic matter; the resulting ΔE a also increased with depth. This suggests that in the dry state, the ''cleaned'' surface of the inorganic soil colloids was more energetic than the ''organic-matter-coater surface''. These data provide strong support for the deduction that OM in the subsoil was in a more ''combined'' state than that in the surface soil. (author). 21 refs, 4 figs, 2 tabs

  5. The Investigation of Isotopic Composition of Precipitation and water vapour by Using Air Mass Trajectories and Meteorological Parameters

    International Nuclear Information System (INIS)

    Dirican, A.; Acar, Y.; Demircan, M.

    2002-01-01

    In last century there are so many studies were carried out about stable isotopes of precipitation. The Researchers, study in this field directed to examine origin and transport of water vapour. To investigate the conditions of precipitation formation parallel with climatic changes, stable isotopes using as a powerful tool. So that a project coordinated by IAEA. In this presentation we will give some parts of this project which was carried out in Turkey. First results were obtained for 2001 year. The one of the first result which was obtained in this project is the relation between air temperature and isotopic composition of precipitation collected in Ankara Antalya and Adana station. Second was the observation of temporal variation of stable isotope composition in precipitation and water vapour in relation with water vapour transport. δD and δ 18 O content of atmospheric water vapour examined for January - December 2001 time interval. 27 precipitation event had been examined, starting from endengered place and following to trajectories until to reach Turkey, by using ground level and 500mbar synoptic charts. The observed δD and δ 18 O variations of water vapour is related with the endengered place (Atlantic Ocean, Mediterranean Sea, etc.) of water vapour. The isotopic composition of local precipitation forms by regional meteorological factors. In this study δD and δ 18 O relation of event, daily precipitation and water vapour were defined

  6. GPS water vapour tomography: preliminary results from the ESCOMPTE field experiment

    Science.gov (United States)

    Champollion, C.; Masson, F.; Bouin, M.-N.; Walpersdorf, A.; Doerflinger, E.; Bock, O.; Van Baelen, J.

    2005-03-01

    Water vapour plays a major role in atmospheric processes but remains difficult to quantify due to its high variability in time and space and the sparse set of available measurements. The GPS has proved its capacity to measure the integrated water vapour at zenith with the same accuracy as other methods. Recent studies show that it is possible to quantify the integrated water vapour in the line of sight of the GPS satellite. These observations can be used to study the 3D heterogeneity of the troposphere using tomographic techniques. We develop three-dimensional tomographic software to model the three-dimensional distribution of the tropospheric water vapour from GPS data. First, the tomographic software is validated by simulations based on the realistic ESCOMPTE GPS network configuration. Without a priori information, the absolute value of water vapour is less resolved as opposed to relative horizontal variations. During the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers was operated for 2 weeks within a 20×20-km area around Marseille (southern France). The network extends from sea level to the top of the Etoile chain (˜700 m high). Optimal results have been obtained with time windows of 30-min intervals and input data evaluation every 15 min. The optimal grid for the ESCOMTE geometrical configuration has a horizontal step size of 0.05°×0.05° and 500 m vertical step size. Second, we have compared the results of real data inversions with independent observations. Three inversions have been compared to three successive radiosonde launches and shown to be consistent. A good resolution compared to the a priori information is obtained up to heights of 3000 m. A humidity spike at 4000-m altitude remains unresolved. The reason is probably that the signal is spread homogeneously over the whole network and that such a feature is not resolvable by tomographic techniques. The results of our pure GPS inversion show a correlation with

  7. Absorption by water vapour in the 1 to 2 μm region

    International Nuclear Information System (INIS)

    Smith, K.M.; Ptashnik, I.; Newnham, D.A.; Shine, K.P.

    2004-01-01

    The near-IR (in the range 5000-10 000 cm -1 , 1-2 μm) bands of water vapour have been measured in absorption in the laboratory at sub-Doppler spectral resolution (up to 0.0054 cm -1 after numerical apodisation) by Fourier transform spectroscopy. Measurements have been made at 296 K on pure water vapour (at pressures between 2 and 20 hPa) and mixtures of water and air (at total pressures of 100 and 1000 hPa), at optical path lengths in the range 0.26-9.75 m. Measured absorption intensities have been compared with values calculated using the HITRAN 2000 molecular database. These comparisons indicate that the intensities of the 2ν(1.4 μm) and 2ν+δ(1.14 μm) bands are underestimated in HITRAN 2000 by approximately 15% and 20%, respectively, for pure water vapour measurements, and 12% for both bands in the case of water-air mixtures. The ν+δ (1.86 μm) band is in good agreement (0.4% for pure water vapour and less than 6% for mixtures with air) with HITRAN 2000. For typical atmospheric conditions, these absorption bands are sufficiently strong that radiation is fully absorbed at wavelengths in the region of the band centres. Hence the extra absorption that has been identified has only a modest impact (0.16 W m -2 or about 0.2%) on the global-mean clear-sky absorption of solar radiation. The impact in the upper troposphere is several times larger

  8. Vertical distribution of deuterium in atmospheric water vapour: problems in application to assess atmospheric condensation models

    International Nuclear Information System (INIS)

    Taylor, C.B.

    1984-01-01

    The paper assesses the use of the author's data by Rozanski and Sonntag to support a multi-box model of the vertical distribution of deuterium in atmospheric water vapour, in which exchange between vapour and falling precipitation produces a steeper deuterium concentration profile than simpler condensation models. The mean deuterium/altitude profile adopted by Rozanski and Sonntag for this purpose is only one of several very different mean profiles obtainable from the data by arbitrary selection and weighting procedures; although it can be made to match the specified multi-box model calculations for deuterium, there is a wide discrepancy between the actual and model mean mixing ratio profiles which cannot be ignored. Taken together, the mixing ratio and deuterium profiles indicate that mean vapour of the middle troposphere has been subjected to condensation at greater heights and lower temperatures than those considered in the model calculations. When this is taken into account, the data actually fit much better to the simpler condensation models. But the vapour samples represent meteorological situations too remote in time from primary precipitation events to permit definite conclusions on cloud system mechanisms. (Auth.)

  9. Removal of bromates from water

    Science.gov (United States)

    Barlokova, D.; Ilavsky, J.; Marko, I.; Tkacova, J.

    2017-10-01

    Bromates are substances that are usually not present in drinking water. They are obtained by ozone disinfection in the presence of bromine ions in water, as an impurity of sodium hypochlorite, respectively. Because of their specific properties, bromates are classified as vary dangers substances, that can cause serious illnesses in humans. There are several technological processes that have been used to the removal of bromates from water at present. In this article, the removal of the bromates from water by the adsorption using various sorbent materials (activated carbon, zeolite, Klinopur-Mn, Bayoxide E33, GEH, Read-As and Activated alumina) are presented. The effectiveness of selected sorbent materials in the removal of bromates from drinking water moves in the interval from 10 to 40%. Based on laboratory results, the zeolite can be used to reduce the concentration of bromates in water.

  10. Prediction of water vapour sorption isotherms and microstructure of hardened Portland cement pastes

    International Nuclear Information System (INIS)

    Burgh, James M. de; Foster, Stephen J.; Valipour, Hamid R.

    2016-01-01

    Water vapour sorption isotherms of cementitious materials reflect the multi-scale physical microstructure through its interaction with moisture. Our ability to understand and predict adsorption and desorption behaviour is essential in the application of modern performance-based approaches to durability analysis, along with many other areas of hygro-mechanical and hygro-chemo-mechanical behaviour. In this paper, a new physically based model for predicting water vapour sorption isotherms of arbitrary hardened Portland cement pastes is presented. Established thermodynamic principles, applied to a microstructure model that develops with hydration, provide a rational basis for predictions. Closed-form differentiable equations, along with a rational consideration of hysteresis and scanning phenomena, makes the model suitable for use in numerical moisture simulations. The microstructure model is reconciled with recently published 1 H NMR and mercury intrusion porosimetry results.

  11. Study of the Quantum Efficiency of CsI Photocathodes Exposed to Oxygen and Water Vapour

    CERN Document Server

    Di Mauro, A; Piuz, François; Schyns, E M; Van Beelen, J B; Williams, T D

    2000-01-01

    The operation of CsI photocathodes in gaseous detectors requires special attention to the purity of the applied gas mixtures.We have studied the influence of oxygen and water vapour contaminations on the performance of CsI photocathodes for theALICE HMPID RICH prototype. Measurements were done through comparison of Cherenkov rings obtained from beamtests. Increased levels of oxygen and water vapour did not show any effect on the performance. The results of this studyfound a direct application in the way of storing CsI photocathodes over long periods nad in particular in the shipment of theHMPID prototype from CERN to the STAR experiment at BNL. (Abstract only available,full text to follow)

  12. Annealing of polycrystalline thin film silicon solar cells in water vapour at sub-atmospheric pressures

    Czech Academy of Sciences Publication Activity Database

    Pikna, Peter; Píč, Vlastimil; Benda, V.; Fejfar, Antonín

    2014-01-01

    Roč. 54, č. 5 (2014), s. 341-347 ISSN 1210-2709 R&D Projects: GA MŠk 7E10061 EU Projects: European Commission(XE) 240826 - PolySiMode Grant - others:AVČR(CZ) M100101216 Institutional support: RVO:68378271 Keywords : passivation * water vapour * thin film solar cell * polycrystalline silicon (poly-Si) * multicrys- talline silicon (m-Si) * Suns-VOC Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use

  13. The influence of heat pre-treatment on the sorption of water vapour on bentonite

    Czech Academy of Sciences Publication Activity Database

    Mokrejš, P.; Zikánová, Arlette; Hradil, David; Štulík, K.; Pacáková, V.; Kočiřík, Milan; Eić, M.

    2005-01-01

    Roč. 11, č. 1 (2005), s. 57-63 ISSN 0929-5607 R&D Projects: GA ČR(CZ) GA104/02/1464; GA MŠk(CZ) LN00A028 Institutional research plan: CEZ:AV0Z40400503 Keywords : adsorption * bentonite * montmorillonite * water vapour Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.323, year: 2005

  14. The effect of coherent stirring on the advection?condensation of water vapour

    OpenAIRE

    Tsang, Yue-Kin; Vanneste, Jacques

    2017-01-01

    Atmospheric water vapour is an essential ingredient of weather and climate. Key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. In order to investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls the moisture...

  15. ANNEALING OF POLYCRYSTALLINE THIN FILM SILICON SOLAR CELLS IN WATER VAPOUR AT SUB-ATMOSPHERIC PRESSURES

    Directory of Open Access Journals (Sweden)

    Peter Pikna

    2014-10-01

    Full Text Available Thin film polycrystalline silicon (poly-Si solar cells were annealed in water vapour at pressures below atmospheric pressure. PN junction of the sample was contacted by measuring probes directly in the pressure chamber filled with steam during passivation. Suns-VOC method and a Lock-in detector were used to monitor an effect of water vapour to VOC of the solar cell during whole passivation process (in-situ. Tested temperature of the sample (55°C – 110°C was constant during the procedure. Open-circuit voltage of a solar cell at these temperatures is lower than at room temperature. Nevertheless, voltage response of the solar cell to the light flash used during Suns-VOC measurements was good observable. Temperature dependences for multicrystalline wafer-based and polycrystalline thin film solar cells were measured and compared. While no significant improvement of thin film poly-Si solar cell parameters by annealing in water vapour at under-atmospheric pressures was observed up to now, in-situ observation proved required sensitivity to changing VOC at elevated temperatures during the process.

  16. Ozone and water vapour in the austral polar stratospheric vortex and sub-vortex

    Directory of Open Access Journals (Sweden)

    E. Peet

    2004-12-01

    Full Text Available In-situ measurements of ozone and water vapour, in the Antarctic lower stratosphere, were made as part of the APE-GAIA mission in September and October 1999. The measurements show a distinct difference above and below the 415K isentrope. Above 415K, the chemically perturbed region of low ozone and water vapour is clearly evident. Below 415K, but still above the tropopause, no sharp meridional gradients in ozone and water vapour were observed. The observations are consistent with analyses of potential vorticity from the European Centre for Medium Range Weather Forecasting, which show smaller radial gradients at 380K than at 450K potential temperature. Ozone loss in the chemically perturbed region above 415K averages 5ppbv per day for mid-September to mid-October. Apparent ozone loss rates in the sub-vortex region are greater, at 7ppbv per day. The data support, therefore, the existence of a sub-vortex region in which meridional transport is more efficient than in the vortex above. The low ozone mixing ratios in the sub-vortex region may be due to in-situ chemical destruction of ozone or transport of ozone-poor air out of the bottom of the vortex. The aircraft data we use cannot distinguish between these two processes. Key words. Meteorology and atmospheric dynamics polar meteorology – Atmospheric composition and structure (middle atmosphere–composition and chemistry

  17. Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour.

    Science.gov (United States)

    Martin, T L; Coe, C; Bagot, P A J; Morrall, P; Smith, G D W; Scott, T; Moody, M P

    2016-07-12

    Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

  18. Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

    Science.gov (United States)

    Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W.; Scott, T.; Moody, M. P.

    2016-07-01

    Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

  19. Energetics and dynamics of the neutralization of clustered ions in ammonia and water vapour

    International Nuclear Information System (INIS)

    Sennhauser, E.S.; Armstrong, D.A.

    1978-01-01

    The energetics and dynamics of neutralization reactions of clustered ions in ammonia and water vapour have been analysed. Neutralization rate coefficients were calculated for the ions in ammonia and for H + .(H 2 O)sub(n) combining with various clustered anions in water vapour up to densities of 4 x 10 19 molecule cm -3 at 390 K. In the case of ammonia, calculations were also performed at 298 K. For all systems, fractional contributions of the neutralization coefficients for specific cluster sizes to the overall coefficient αsub(eff) were evaluated. The computed value of αsub(eff) for NH 3 was in reasonable agreement with experimental data in the [NH 3 ] range 0.3 to 4 x 10 19 molecule cm -3 , and general trends stemming from the effects of increasing ion mass were pointed out. Calculations of energies of individual cluster sizes indicate possible neutralization reaction mechanisms. With some exception, proton transfer is the only possible path and no H atoms should be formed. This is in general agreement with literature results for water vapour at approximately 390 K and with [H 2 O] >= 2 x 10 x 10 19 molecule cm -3 . (author)

  20. Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

    Science.gov (United States)

    Cieśla, Jolanta; Sokołowska, Zofia; Witkowska-Walczak, Barbara; Skic, Kamil

    2018-01-01

    Water vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0-1 range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

  1. Remote sensing of water vapour profiles in the framework of the Total Carbon Column Observing Network (TCCON

    Directory of Open Access Journals (Sweden)

    M. Schneider

    2010-12-01

    Full Text Available We show that the near infrared solar absorption spectra recorded in the framework of the Total Carbon Column Observing Network (TCCON can be used to derive the vertical distribution of tropospheric water vapour. The resolution of the TCCON spectra of 0.02 cm−1 is sufficient for retrieving lower and middle/upper tropospheric water vapour concentrations with a vertical resolution of about 3 and 8 km, respectively. We document the good quality of the remotely-sensed profiles by comparisons with coincident in-situ Vaisala RS92 radiosonde measurements. Due to the high measurement frequency, the TCCON water vapour profile data offer novel opportunities for estimating the water vapour variability at different timescales and altitudes.

  2. Middle atmospheric water vapour and dynamics in the vicinity of the polar vortex during the Hygrosonde-2 campaign

    Directory of Open Access Journals (Sweden)

    S. Lossow

    2009-07-01

    Full Text Available The Hygrosonde-2 campaign took place on 16 December 2001 at Esrange/Sweden (68° N, 21° E with the aim to investigate the small scale distribution of water vapour in the middle atmosphere in the vicinity of the Arctic polar vortex. In situ balloon and rocket-borne measurements of water vapour were performed by means of OH fluorescence hygrometry. The combined measurements yielded a high resolution water vapour profile up to an altitude of 75 km. Using the characteristic of water vapour being a dynamical tracer it was possible to directly relate the water vapour data to the location of the polar vortex edge, which separates air masses of different character inside and outside the polar vortex. The measurements probed extra-vortex air in the altitude range between 45 km and 60 km and vortex air elsewhere. Transitions between vortex and extra-vortex usually coincided with wind shears caused by gravity waves which advect air masses with different water vapour volume mixing ratios.

    From the combination of the results from the Hygrosonde-2 campaign and the first flight of the optical hygrometer in 1994 (Hygrosonde-1 a clear picture of the characteristic water vapour distribution inside and outside the polar vortex can be drawn. Systematic differences in the water vapour concentration between the inside and outside of the polar vortex can be observed all the way up into the mesosphere. It is also evident that in situ measurements with high spatial resolution are needed to fully account for the small-scale exchange processes in the polar winter middle atmosphere.

  3. UTLS water vapour from SCIAMACHY limb measurementsV3.01 (2002-2012).

    Science.gov (United States)

    Weigel, K; Rozanov, A; Azam, F; Bramstedt, K; Damadeo, R; Eichmann, K-U; Gebhardt, C; Hurst, D; Kraemer, M; Lossow, S; Read, W; Spelten, N; Stiller, G P; Walker, K A; Weber, M; Bovensmann, H; Burrows, J P

    2016-01-01

    The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard the Envisat satellite provided measurements from August 2002 until April 2012. SCIAMACHY measured the scattered or direct sunlight using different observation geometries. The limb viewing geometry allows the retrieval of water vapour at about 10-25 km height from the near-infrared spectral range (1353-1410 nm). These data cover the upper troposphere and lower stratosphere (UTLS), a region in the atmosphere which is of special interest for a variety of dynamical and chemical processes as well as for the radiative forcing. Here, the latest data version of water vapour (V3.01) from SCIAMACHY limb measurements is presented and validated by comparisons with data sets from other satellite and in situ measurements. Considering retrieval tests and the results of these comparisons, the V3.01 data are reliable from about 11 to 23 km and the best results are found in the middle of the profiles between about 14 and 20 km. Above 20 km in the extra tropics V3.01 is drier than all other data sets. Additionally, for altitudes above about 19 km, the vertical resolution of the retrieved profile is not sufficient to resolve signals with a short vertical structure like the tape recorder. Below 14 km, SCIAMACHY water vapour V3.01 is wetter than most collocated data sets, but the high variability of water vapour in the troposphere complicates the comparison. For 14-20 km height, the expected errors from the retrieval and simulations and the mean differences to collocated data sets are usually smaller than 10 % when the resolution of the SCIAMACHY data is taken into account. In general, the temporal changes agree well with collocated data sets except for the Northern Hemisphere extratropical stratosphere, where larger differences are observed. This indicates a possible drift in V3.01 most probably caused by the incomplete treatment of volcanic aerosols in the retrieval. In all other regions a

  4. Characterization of sorption properties of selected soils from Lublin region by using water vapour adsorption method

    Science.gov (United States)

    Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

    2016-04-01

    *The studies were carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545 Among many methods proposed to study sorption properties of soils an analysis of adsorption/ desorption isotherm is probably the easiest and most convenient one. It characterizes both quantity and quality of mineral and organic components and also their physical and physicochemical properties. The main aim of this study is comparison of sorption properties of selected Polish soils by using water vapour adsorption method. Samples were taken from the depth of 0-20 cm, from the Lublin region, eastern Poland. Soils were selected on the basis of their different physicochemical properties and were classified as: Haplic Fluvisol, Haplic Chernozem, Mollic Gleysol, Rendzic Phaeozem, Stagnic Luvisol, Haplic Cambisol (WG WRB 2006). Data taken from experimental adsorption isotherms were used to determine parameters of monolayer capacity, specific surface area and the total amount of vapour adsorbed at relative pressure of 0.974. Obtained adsorption and desorption isotherms reviled that adsorbate molecules interacted with the soil particles in different extent. Similar monolayer capacity was observed for Haplic Fluvisol, Haplic Chernozem and Stagnic Luvisol, while for Mollic Gleysol was more than 4 times higher. Mollic Gleysol was also characterized by highest values of specific surface area as well as quantity of adsorbed vapour at relative pressure of 0.974. Higher sorption was caused by presence of soil colloids which contains functional groups of a polar nature (mainly hydroxyls, phenolic and carboxyls). These groups similarly to silicates, oxides, hydratable cations as well as electric charge form adsorption centres for water vapour molecules.

  5. The exchange reaction between deuterium and water vapour on platinum deposited over a hydrophobic support

    International Nuclear Information System (INIS)

    Itsuo, Iida; Junko, Kato; Kenzi, Tamuru

    1977-01-01

    Isotope exchange reaction between deuterium gas and water vapour at room temperature and below on platinum deposited on hydrophobic supports such as polytetrafluoroethylene (PTFE) or Porapak Q (copolymer of styrene and divinylbenzene) was studied and the results were compared with those of the exchange reaction on platinum over hydrophilic support such as alumina. It was demonstrated that the exchange reaction at temperatures below the boiling point of water is markedly retarded by the multilayer adsorption of water over the platinum catalyst deposited on hydrophilic support, whereas the platinum catalyst on hydrophobic support exhibited a high catalytic activity, being not retarded by the water, forming no multilayer of adsorbed water over platinum surface. Therefore in the case of the hydrogen isotope exchange reaction on platinum over hydrophobic support, the chemical exchange rate can be measured even under a saturated vapour pressure of water. The surface area of platinum was estimated by hydrogen chemisorption and hydrogen titration and specific activities of the catalyst were calculated at both room temperature and freezing point of water, which revealed that the specific rate of this reaction does not differ so much over various supports. (orig.) [de

  6. Electron drift velocities in He and water mixtures: Measurements and an assessment of the water vapour cross-section sets

    International Nuclear Information System (INIS)

    Urquijo, J. de; Juárez, A. M.; Basurto, E.; Ness, K. F.; Robson, R. E.; White, R. D.; Brunger, M. J.

    2014-01-01

    The drift velocity of electrons in mixtures of gaseous water and helium is measured over the range of reduced electric fields 0.1–300 Td using a pulsed-Townsend technique. Admixtures of 1% and 2% water to helium are found to produce negative differential conductivity (NDC), despite NDC being absent from the pure gases. The measured drift velocities are used as a further discriminative assessment on the accuracy and completeness of a recently proposed set of electron-water vapour cross-sections [K. F. Ness, R. E. Robson, M. J. Brunger, and R. D. White, J. Chem. Phys. 136, 024318 (2012)]. A refinement of the momentum transfer cross-section for electron-water vapour scattering is presented, which ensures self-consistency with the measured drift velocities in mixtures with helium to within approximately 5% over the range of reduced fields considered

  7. Stable isotope characterization of pan-derived and directly sampled atmospheric water vapour

    International Nuclear Information System (INIS)

    Maric, R.; St. Amour, N.A.; Gibson, J.J.; Edwards, T.W.D.

    2002-01-01

    Isotopic characterization of atmospheric water vapour, δ A , and its temporal variability are important prerequisites for quantifying water balance of surface reservoirs and partitioning of evaporation and transpiration fluxes using isotope techniques. Here we present results from a detailed comparison of several methods for determining δ A in field situations, (i) by back-calculation from isotopic and micrometeorological monitoring of a steady-state terminal reservoir (standard Class-A evaporation pan) using boundary-layer mass transfer models [1], (ii) through direct (cryogenic) sampling of ambient atmospheric moisture, and (iii) using the precipitation-equilibrium approximation (i.e., δ A =δ P - ε*)

  8. Efficient quantification of water content in edible oils by headspace gas chromatography with vapour phase calibration.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2018-06-01

    An automated and accurate headspace gas chromatographic (HS-GC) technique was investigated for rapidly quantifying water content in edible oils. In this method, multiple headspace extraction (MHE) procedures were used to analyse the integrated water content from the edible oil sample. A simple vapour phase calibration technique with an external vapour standard was used to calibrate both the water content in the gas phase and the total weight of water in edible oil sample. After that the water in edible oils can be quantified. The data showed that the relative standard deviation of the present HS-GC method in the precision test was less than 1.13%, the relative differences between the new method and a reference method (i.e. the oven-drying method) were no more than 1.62%. The present HS-GC method is automated, accurate, efficient, and can be a reliable tool for quantifying water content in edible oil related products and research. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. Removal and recovery of tritium from light and heavy water

    International Nuclear Information System (INIS)

    Butler, J.P.; Hammerli, M.

    1979-01-01

    A method and apparatus for removing tritium from light water are described, comprising contacting tritiated feed water in a catalyst column in countercurrent flow with hydrogen gas originating from an electrolysis cell so as to enrich this feed water with tritium from the electrolytic hydrogen gas and passing the tritium enriched water to an electrolysis cell wherein the electrolytic hydrogen gas is generated and then fed upwards through the catalyst column or recovered as product. The tritium content of the hydrogen gas leaving the top of the enricher catalyst column is further reduced in a stripper column containing catalyst which transfers the tritium to a countercurrent flow of liquid water. Anodic oxygen and water vapour from the anode compartment may be fed to a drier and condensed electrolyte recycled with a slip stream or recovered as a further tritium product stream. A similar method involving heavy water is also described. (author)

  10. The ratio DT/μ for electrons in water vapour at 294 K

    International Nuclear Information System (INIS)

    Elford, M.T.

    1995-01-01

    The ratio D T /μ for electrons in water vapour (294 K) has been measured by the Townsend-Huxley method as a function of E/N (where E is the electric field strength and N the gas number density) at vapour pressures ranging from 0.103 to 0.413 kPa. For E/N ≤ 30 Td, where attachment and ionisation may be neglected, the values are found to be independent of vapour pressure and of the current ratio relation used to derive D T /μ values from the measured current ratios. The uncertainty of these D T /μ values is estimated to be T /μ measured at E/N > 30 Td were found to be strongly pressure dependent, the strength and sign of the dependence depending on E/N and the current ratio relation used. Since extrapolation to infinite pressure at each E/N value did not give the same value of D T /μ, it has not been possible to derive reliable D T /μ values for this higher E/N range. Possible causes of the observed pressure dependences are discussed. The present data are in good agreement with the values predicted by Ness and Robson for values of E/N ≤ 24 Td. 17 refs., 1 tab., 5 figs

  11. Dynamic behaviour of bubbles of water vapour at a temperature lower than the boiling temperature

    International Nuclear Information System (INIS)

    Jansen, Franz

    1966-01-01

    This research thesis reports the study of the theoretical movement of the wall of vapour water bubbles in a sub-saturated boiling regime, i.e. with an average water temperature lower than the boiling temperature. While assuming that bubbles have an initial translational speed at the beginning of their condensation, the author shows that their shrinkage should result in an accelerated displacement in a direction normal to the wall and inward the liquid. Layers of hot water initially close to the wall would therefore be quickly transported towards cold water areas. Experiments allowed, in some cases, the acceleration of bubbles during their condensation to be noticed: for low sub-saturations in still water and for high sub-saturations in water in forced convection, even though, in this last case, the determination of accelerations is more delicate [fr

  12. The early summertime Saharan heat low: sensitivity of the radiation budget and atmospheric heating to water vapour and dust aerosol

    Science.gov (United States)

    Alamirew, Netsanet K.; Todd, Martin C.; Ryder, Claire L.; Marsham, John H.; Wang, Yi

    2018-01-01

    The Saharan heat low (SHL) is a key component of the west African climate system and an important driver of the west African monsoon across a range of timescales of variability. The physical mechanisms driving the variability in the SHL remain uncertain, although water vapour has been implicated as of primary importance. Here, we quantify the independent effects of variability in dust and water vapour on the radiation budget and atmospheric heating of the region using a radiative transfer model configured with observational input data from the Fennec field campaign at the location of Bordj Badji Mokhtar (BBM) in southern Algeria (21.4° N, 0.9° E), close to the SHL core for June 2011. Overall, we find dust aerosol and water vapour to be of similar importance in driving variability in the top-of-atmosphere (TOA) radiation budget and therefore the column-integrated heating over the SHL (˜ 7 W m-2 per standard deviation of dust aerosol optical depth - AOD). As such, we infer that SHL intensity is likely to be similarly enhanced by the effects of dust and water vapour surge events. However, the details of the processes differ. Dust generates substantial radiative cooling at the surface (˜ 11 W m-2 per standard deviation of dust AOD), presumably leading to reduced sensible heat flux in the boundary layer, which is more than compensated by direct radiative heating from shortwave (SW) absorption by dust in the dusty boundary layer. In contrast, water vapour invokes a radiative warming at the surface of ˜ 6 W m-2 per standard deviation of column-integrated water vapour in kg m-2. Net effects involve a pronounced net atmospheric radiative convergence with heating rates on average of 0.5 K day-1 and up to 6 K day-1 during synoptic/mesoscale dust events from monsoon surges and convective cold-pool outflows (haboobs). On this basis, we make inferences on the processes driving variability in the SHL associated with radiative and advective heating/cooling. Depending on the

  13. GLYPHOSATE REMOVAL FROM DRINKING WATER

    Science.gov (United States)

    Activated-carbon, oxidation, conventional-treatment, filtration, and membrane studies are conducted to determine which process is best suited to remove the herbicide glyphosate from potable water. Both bench-scale and pilot-scale studies are completed. Computer models are used ...

  14. Water vapour and wind measurements by a two micron space lidar

    Science.gov (United States)

    Ghibaudo, J.-B.; Labandibar, J.-Y.

    2018-04-01

    AEROSPATIALE presents the main results of the feasibility study under ESA contract on a coherent 2μm lidar instrument capable of measuring water vapour and wind velocity in the planetary boundary layer. The selected instrument configuration and the associated performance are provided, and the main critical subsystems identified (laser configuration, coherent receiver chain architecture, frequency locking and offsetting architecture. The second phase of this study is dedicated to breadboard the most critical elements of such an instrument in order to technologically consolidate its feasibility.

  15. Passivation effect of water vapour on thin film polycrystalline Si solar cells

    Czech Academy of Sciences Publication Activity Database

    Pikna, Peter; Müller, Martin; Becker, C.; Fejfar, Antonín

    2016-01-01

    Roč. 213, č. 7 (2016), s. 1969-1975 ISSN 1862-6300 R&D Projects: GA MŠk LM2015087; GA ČR GA13-12386S Grant - others:AV ČR(CZ) DAAD-16-27 Program:Bilaterální spolupráce Institutional support: RVO:68378271 Keywords : passivation, * plasma hydrogenation * silicon * solar cells * thin films * water vapour Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.775, year: 2016

  16. Water vapour flux divergence over the Arabian Sea during 1987 summer monsoon using satellite data

    Digital Repository Service at National Institute of Oceanography (India)

    Vinayachandran, P.N.; RameshKumar, M.R.

    the AS or the southern Indian Ocean. Another question which remains unanswered is whether all the NFD over AS is utilized only for precipitation over the Indian subcontinent or part of it is utilized for precipitation over the other southeast Asian countries. Only a... detailed and systematic surface and upper air data collection programme over the tropical Indian Ocean can throw light on the above questions. WATER VAPOUR FLUX DIVERGENCE OVER THE ARABIAN SEA 207 500 60’ 700 80” 500 60” 70” 500 60’ 70” 60” 700 Fig. 7...

  17. Competition for water vapour results in suppression of ice formation in mixed-phase clouds

    Directory of Open Access Journals (Sweden)

    E. L. Simpson

    2018-05-01

    Full Text Available The formation of ice in clouds can initiate precipitation and influence a cloud's reflectivity and lifetime, affecting climate to a highly uncertain degree. Nucleation of ice at elevated temperatures requires an ice nucleating particle (INP, which results in so-called heterogeneous freezing. Previously reported measurements for the ability of a particle to nucleate ice have been made in the absence of other aerosol which will act as cloud condensation nuclei (CCN and are ubiquitous in the atmosphere. Here we show that CCN can outcompete INPs for available water vapour thus suppressing ice formation, which has the potential to significantly affect the Earth's radiation budget. The magnitude of this suppression is shown to be dependent on the mass of condensed water required for freezing. Here we show that ice formation in a state-of-the-art cloud parcel model is strongly dependent on the criteria for heterogeneous freezing selected from those previously hypothesised. We have developed an alternative criteria which agrees well with observations from cloud chamber experiments. This study demonstrates the dominant role that competition for water vapour can play in ice formation, highlighting both a need for clarity in the requirements for heterogeneous freezing and for measurements under atmospherically appropriate conditions.

  18. Electrical Behaviour of Chitosan-Silver Nanocomposite in Presence of Water Vapour

    Directory of Open Access Journals (Sweden)

    Bal Yadav

    2017-04-01

    Full Text Available This paper presents the synthesis, characterization of the nanocomposite of silver and chitosan polymer composite reinforced by cellulose fibre and its electrical behaviour in presence of water vapour. The coated paper has been characterized by XRD, IR, SEM and EDX techniques. The size of silver nanoparticles is found to be around 9 nm and deposited uniformly. Chitosan, as well as cellulose, contain a hydrogen attached to electronegative nitrogen and oxygen. This gives a favourable environment for the formation of hydrogen bonds. IR peaks of the composite infer the intermolecular hydrogen bonding between the two constituents. The SEM pictures show that the coating of the fibres with nanoparticles is quite uniform. EDX analysis shows that the coated filter paper has sufficient amount of silver along with carbon and oxygen. The coated paper shows good sensitivity towards humidity. It gives excellent linearity in response with a concentration of water vapour after heat treatment of composite at 130 °C. The sensitivity of the sensor is 0.8 MΩ per unit of relative humidity. Sensing properties originate from protonic conductivity from adsorbed water molecule.

  19. Competition for water vapour results in suppression of ice formation in mixed-phase clouds

    Science.gov (United States)

    Simpson, Emma L.; Connolly, Paul J.; McFiggans, Gordon

    2018-05-01

    The formation of ice in clouds can initiate precipitation and influence a cloud's reflectivity and lifetime, affecting climate to a highly uncertain degree. Nucleation of ice at elevated temperatures requires an ice nucleating particle (INP), which results in so-called heterogeneous freezing. Previously reported measurements for the ability of a particle to nucleate ice have been made in the absence of other aerosol which will act as cloud condensation nuclei (CCN) and are ubiquitous in the atmosphere. Here we show that CCN can outcompete INPs for available water vapour thus suppressing ice formation, which has the potential to significantly affect the Earth's radiation budget. The magnitude of this suppression is shown to be dependent on the mass of condensed water required for freezing. Here we show that ice formation in a state-of-the-art cloud parcel model is strongly dependent on the criteria for heterogeneous freezing selected from those previously hypothesised. We have developed an alternative criteria which agrees well with observations from cloud chamber experiments. This study demonstrates the dominant role that competition for water vapour can play in ice formation, highlighting both a need for clarity in the requirements for heterogeneous freezing and for measurements under atmospherically appropriate conditions.

  20. Retrieval of total water vapour in the Arctic using microwave humidity sounders

    Science.gov (United States)

    Cristian Scarlat, Raul; Melsheimer, Christian; Heygster, Georg

    2018-04-01

    Quantitative retrievals of atmospheric water vapour in the Arctic present numerous challenges because of the particular climate characteristics of this area. Here, we attempt to build upon the work of Melsheimer and Heygster (2008) to retrieve total atmospheric water vapour (TWV) in the Arctic from satellite microwave radiometers. While the above-mentioned algorithm deals primarily with the ice-covered central Arctic, with this work we aim to extend the coverage to partially ice-covered and ice-free areas. By using modelled values for the microwave emissivity of the ice-free sea surface, we develop two sub-algorithms using different sets of channels that deal solely with open-ocean areas. The new algorithm extends the spatial coverage of the retrieval throughout the year but especially in the warmer months when higher TWV values are frequent. The high TWV measurements over both sea-ice and open-water surfaces are, however, connected to larger uncertainties as the retrieval values are close to the instrument saturation limits.This approach allows us to apply the algorithm to regions where previously no data were available and ensures a more consistent physical analysis of the satellite measurements by taking into account the contribution of the surface emissivity to the measured signal.

  1. Airborne hygrometer calibration inter-comparison against a metrological water vapour standard

    Science.gov (United States)

    Smorgon, Denis; Boese, Norbert; Ebert, Volker

    2014-05-01

    Water vapour is the most important atmospheric greenhouse gas, which causes a major feedback to warming and other changes in the climate system. Knowledge of the distribution of water vapour and its climate induced changes is especially important in the upper troposphere and lower stratosphere (UT/LS) where vapour plays a critical role in atmospheric radiative balance, cirrus cloud formation, and photochemistry. But, our understanding of water in the UT/LS is limited by significant uncertainties in current UT/LS water measurements. One of the most comprehensive inter-comparison campaigns for airborne hygrometers, termed AQUAVIT (AV1) [1], took place in 2007 at the AIDA chamber at the Karlsruhe Institute of Technology (KIT) in Germany. AV1 was a well-defined, referred, blind inter-comparison of 22 airborne field instruments from 17 international research groups. One major metrological deficit of AV1, however, was, that no traceable reference instrument participated in the inter-comparison experiments and that the calibration procedures of the participating instruments were not monitored or interrogated. Consequently a follow-up inter-comparison was organized in April 2013, which for the first time also provides a traceable link to the international humidity scale. This AQUAVIT2 (AV2) campaign (details see: http://www.imk-aaf.kit.edu/aquavit/index.php/Main_Page) was again located at KIT/AIDA and organised by an international organizing committee including KIT, PTB, FZJ and others. Generally AV2 is divided in two parallel comparisons: 1) AV2-A uses the AIDA chamber for a simultaneous comparison of all instruments (incl. sampling and in-situ instruments) over a broad range of conditions characteristic for the UT/LS; 2) AV2-B, about which this paper is reporting, is a sequential comparison of selected hygrometers and (when possible) their reference calibration infrastructures by means of a chilled mirror hygrometer traced back to the primary National humidity standard

  2. The oxidation of stainless steels in water vapour-oxygen mixtures. Design and development of an original equipment

    International Nuclear Information System (INIS)

    Uller, Leonardo.

    1981-02-01

    A device including a thermobalance placed in a tight housing has been conceived and built. This apparatus is suitable to submit metallic samples to the action of dry oxygen, deoxygenated water vapour or mixtures of water vapour and oxygen. The first results obtained with this device, at 600 0 C, and for a 18-10 stainless steel are: - in the presence of deoxygenated water vapour, one observes very fast oxidation kinetics, with a roughly parabolic law (K approximately equal to 3x10 -2 mg 2 .cm -4 .h -1 ); - the addition of oxygen from about 10 vpm onwards, induces an important initial slowing down of the kinetics; - the duration of this 'induction' period rises with increasing the oxygen content of the water vapour, but the protection of the alloy due to the action of oxygen remains temporary; - in another way, experiments begun with water vapour, were continued with pure oxygen, and reciprocally. During these 'mixed' experiments, the weight increases were continually recorded. A swift slowing down has been observed in the first case and an important acceleration in the second one [fr

  3. Data on thermal conductivity, water vapour permeability and water absorption of a cementitious mortar containing end-of-waste plastic aggregates

    OpenAIRE

    Di Maio, Luciano; Coppola, Bartolomeo; Courard, Luc; Michel, Frédéric; Incarnato, Loredana; Scarfato, Paola

    2018-01-01

    The data presented in this article are related to the research article entitled “Hygro-thermal and durability properties of a lightweight mortar made with foamed plastic waste aggregates ” (Coppola et al., 2018). This article focuses the attention on thermal conductivity, water vapour permeability and water absorption of a lightweight cementitious mortar containing foamed end-of-waste plastic aggregates, produced via foam extrusion process. Thermal conductivity, water vapour permeability ...

  4. Intercomparison of in-situ and remote sensing δD signals in tropospheric water vapour

    Science.gov (United States)

    Schneider, Matthias; González, Yenny; Dyroff, Christoph; Christner, Emanuel; García, Omaira; Wiegele, Andreas; Andrey, Javier; Barthlott, Sabine; Blumenstock, Thomas; Guirado, Carmen; Hase, Frank; Ramos, Ramon; Rodríguez, Sergio; Sepúveda, Eliezer

    2014-05-01

    The main mission of the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) is the generation of a quasi-global tropospheric water vapour isototopologue dataset of a good and well-documented quality. We present a first empirical validation of MUSICA's remote sensing δD products (ground-based FTIR within NDACC, Network for the Detection of Atmospheric Composition Change, and space-based with IASI, Infrared Atmospheric Sounding Interferometer, flown on METOP). As reference we use in-situ measurements made on the island of Tenerife at two different altitudes (2370 and 3550 m a.s.l., using two Picarro L2120-i water isotopologue analyzers) and aboard an aircraft (between 200 and 6800 m a.s.l., using the homemade ISOWAT instrument).

  5. REFIR/BB initial observations in the water vapour rotational band: Results from a field campaign

    International Nuclear Information System (INIS)

    Esposito, F.; Grieco, G.; Leone, L.; Restieri, R.; Serio, C.; Bianchini, G.; Palchetti, L.; Pellegrini, M.; Cuomo, V.; Masiello, G.; Pavese, G.

    2007-01-01

    There is a growing interest in the far infrared spectral region 17-50 μm as a remote sensing tool in atmospheric sciences, since this portion of the spectrum contains the characteristic molecular rotational band for water vapour. Much of the Earth energy lost to space is radiated through this spectral region. The Radiation Explorer in the Far InfraRed Breadboard (REFIR/BB) spectrometer was born because of the quest to make observations in the far infrared. REFIR/BB is a Fourier Transform Spectrometer with a sampling resolution of 0.5 cm -1 and it was tested for the first time in the field to check its reliability and radiometric performance. The field campaign was held at Toppo di Castelgrande (40 o 49' N, 15 o 27' E, 1258 m a. s. l.), a mountain site in South Italy. The spectral and radiometric performance of the instrument and initial observations are shown in this paper. Comparisons to both (1) BOMEM MR100 Fourier Transform spectrometer observations and (2) line-by-line radiative transfer calculations for selected clear sky are presented and discussed. These comparisons (1) show a very nice agreement between radiance measured by REFIR/BB and by BOMEM MR100 and (2) demonstrate that REFIR/BB accurately observes the very fine spectral structure in the water vapour rotational band

  6. The effect of coherent stirring on the advection–condensation of water vapour

    Science.gov (United States)

    Vanneste, Jacques

    2017-01-01

    Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow. PMID:28690417

  7. The effect of coherent stirring on the advection-condensation of water vapour

    Science.gov (United States)

    Tsang, Yue-Kin; Vanneste, Jacques

    2017-06-01

    Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow.

  8. Intercomparison of radiative forcing calculations of stratospheric water vapour and contrails

    Energy Technology Data Exchange (ETDEWEB)

    Myhre, Gunnar [Dept. of Geosciences, Univ. of Oslo (Norway); Center for International Climate and Environmental Research-Oslo (CICERO), Oslo (Norway); Kvalevaag, Maria [Dept. of Geosciences, Univ. of Oslo (Norway); Raedel, Gaby; Cook, Jolene; Shine, Keith P. [Dept. of Meteorology, Univ. of Reading (United Kingdom); Clark, Hannah [CNRM/GAME Meteo France, Toulouse (France); Lab. d' Aerologie, Univ. de Toulouse (France); Karcher, Fernand [CNRM/GAME Meteo France, Toulouse (France); Markowicz, Krzysztof; Kardas, Aleksandra; Wolkenberg, Paulina [Inst. of Geophysics, Univ. of Warsaw (Poland); Balkanski, Yves [LSCE/IPSL, Lab. CEA-CNRS-UVSQ (France); Ponater, Michael [Deutsches Zentrum fuer Luft und Raumfahrt (DLR), Inst. fuer Physik der Atmosphaere, Oberpfaffenhofen (Germany); Forster, Piers; Rap, Alexandru [School of Earth and Environment, Univ. of Leeds (United Kingdom); Leon, Ruben Rodriguez de [Manchester Metropolitan Univ. (United Kingdom)

    2009-12-15

    Seven groups have participated in an intercomparison study of calculations of radiative forcing (RF) due to stratospheric water vapour (SWV) and contrails. a combination of detailed radiative transfer schemes and codes for global-scale calculations have been used, as well as a combination of idealized simulations and more realistic global-scale changes in stratospheric water vapour and contrails. Detailed line-by-line codes agree within about 15% for longwave (LW) and shortwave (SW) RF, except in one case where the difference is 30%. Since the LW and SW RF due to contrails and SWV changes are of opposite sign, the differences between the models seen in the individual LW and SW components can be either compensated or strengthened in the net RF. and thus in relative terms uncertainties are much larger for the net RF. Some of the models used for global-scale simulations of changes in SWV and contrails differ substantially in RF from the more detailed radiative transfer schemes. For the global-scale calculations we use a method of weighting the results to calculate a best estimate based on their performance compared to the more detailed radiative transfer schemes in the idealized simulations. (orig.)

  9. Analysis of the sorption properties of different soils using water vapour adsorption and potentiometric titration methods

    Science.gov (United States)

    Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

    2016-07-01

    Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g-1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=-0.736; α = 0.05) as well as ash content (R=-0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g-1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.

  10. High mean water vapour pressure promotes the transmission of bacillary dysentery.

    Directory of Open Access Journals (Sweden)

    Guo-Zheng Li

    Full Text Available Bacillary dysentery is an infectious disease caused by Shigella dysenteriae, which has a seasonal distribution. External environmental factors, including climate, play a significant role in its transmission. This paper identifies climate-related risk factors and their role in bacillary dysentery transmission. Harbin, in northeast China, with a temperate climate, and Quzhou, in southern China, with a subtropical climate, are chosen as the study locations. The least absolute shrinkage and selectionator operator is applied to select relevant climate factors involved in the transmission of bacillary dysentery. Based on the selected relevant climate factors and incidence rates, an AutoRegressive Integrated Moving Average (ARIMA model is established successfully as a time series prediction model. The numerical results demonstrate that the mean water vapour pressure over the previous month results in a high relative risk for bacillary dysentery transmission in both cities, and the ARIMA model can successfully perform such a prediction. These results provide better explanations for the relationship between climate factors and bacillary dysentery transmission than those put forth in other studies that use only correlation coefficients or fitting models. The findings in this paper demonstrate that the mean water vapour pressure over the previous month is an important predictor for the transmission of bacillary dysentery.

  11. Removal of radium from drinking water

    International Nuclear Information System (INIS)

    Lauch, R.P.

    1992-08-01

    The report summarizes processes for removal of radium from drinking water. Ion exchange, including strong acid and weak acid resin, is discussed. Both processes remove better than 95 percent of the radium from the water. Weak acid ion exchange does not add sodium to the water. Calcium cation exchange removes radium and can be used when hardness removal is not necessary. Iron removal processes are discussed in relation to radium removal. Iron oxides remove much less than 20 percent of the radium from water under typical conditions. Manganese dioxide removes radium from water when competition for sorption sites and clogging of sites is reduced. Filter sand that is rinsed daily with dilute acid will remove radium from water. Manganese dioxide coated filter sorption removes radium but more capacity would be desirable. The radium selective complexer selectively removes radium with significant capacity if iron fouling is eliminated

  12. Water Distribution and Removal Model

    International Nuclear Information System (INIS)

    Y. Deng; N. Chipman; E.L. Hardin

    2005-01-01

    The design of the Yucca Mountain high level radioactive waste repository depends on the performance of the engineered barrier system (EBS). To support the total system performance assessment (TSPA), the Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is developed to describe the thermal, mechanical, chemical, hydrological, biological, and radionuclide transport processes within the emplacement drifts, which includes the following major analysis/model reports (AMRs): (1) EBS Water Distribution and Removal (WD and R) Model; (2) EBS Physical and Chemical Environment (P and CE) Model; (3) EBS Radionuclide Transport (EBS RNT) Model; and (4) EBS Multiscale Thermohydrologic (TH) Model. Technical information, including data, analyses, models, software, and supporting documents will be provided to defend the applicability of these models for their intended purpose of evaluating the postclosure performance of the Yucca Mountain repository system. The WD and R model ARM is important to the site recommendation. Water distribution and removal represents one component of the overall EBS. Under some conditions, liquid water will seep into emplacement drifts through fractures in the host rock and move generally downward, potentially contacting waste packages. After waste packages are breached by corrosion, some of this seepage water will contact the waste, dissolve or suspend radionuclides, and ultimately carry radionuclides through the EBS to the near-field host rock. Lateral diversion of liquid water within the drift will occur at the inner drift surface, and more significantly from the operation of engineered structures such as drip shields and the outer surface of waste packages. If most of the seepage flux can be diverted laterally and removed from the drifts before contacting the wastes, the release of radionuclides from the EBS can be controlled, resulting in a proportional reduction in dose release at the accessible environment

  13. Water Distribution and Removal Model

    Energy Technology Data Exchange (ETDEWEB)

    Y. Deng; N. Chipman; E.L. Hardin

    2005-08-26

    The design of the Yucca Mountain high level radioactive waste repository depends on the performance of the engineered barrier system (EBS). To support the total system performance assessment (TSPA), the Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is developed to describe the thermal, mechanical, chemical, hydrological, biological, and radionuclide transport processes within the emplacement drifts, which includes the following major analysis/model reports (AMRs): (1) EBS Water Distribution and Removal (WD&R) Model; (2) EBS Physical and Chemical Environment (P&CE) Model; (3) EBS Radionuclide Transport (EBS RNT) Model; and (4) EBS Multiscale Thermohydrologic (TH) Model. Technical information, including data, analyses, models, software, and supporting documents will be provided to defend the applicability of these models for their intended purpose of evaluating the postclosure performance of the Yucca Mountain repository system. The WD&R model ARM is important to the site recommendation. Water distribution and removal represents one component of the overall EBS. Under some conditions, liquid water will seep into emplacement drifts through fractures in the host rock and move generally downward, potentially contacting waste packages. After waste packages are breached by corrosion, some of this seepage water will contact the waste, dissolve or suspend radionuclides, and ultimately carry radionuclides through the EBS to the near-field host rock. Lateral diversion of liquid water within the drift will occur at the inner drift surface, and more significantly from the operation of engineered structures such as drip shields and the outer surface of waste packages. If most of the seepage flux can be diverted laterally and removed from the drifts before contacting the wastes, the release of radionuclides from the EBS can be controlled, resulting in a proportional reduction in dose release at the accessible environment. The purposes

  14. Water vapour source impacts on oxygen isotope variability in tropical precipitation during Heinrich events

    Directory of Open Access Journals (Sweden)

    S. C. Lewis

    2010-06-01

    Full Text Available Water isotope records such as speleothems provide extensive evidence of past tropical hydrological changes. During Heinrich events, isotopic changes in monsoon regions have been interpreted as implying a widespread drying through the Northern Hemisphere tropics and an anti-phased precipitation response in the south. Here, we examine the sources of this variability using a water isotope-enabled general circulation model, Goddard Institute for Space Studies ModelE. We incorporate a new suite of vapour source distribution tracers to help constrain the impact of precipitation source region changes on the isotopic composition of precipitation and to identify nonlocal amount effects. We simulate a collapse of the North Atlantic meridional overturning circulation with a large freshwater input to the region as an idealised analogue to iceberg discharge during Heinrich events. An increase in monsoon intensity, defined by vertical wind shear, is modelled over the South American domain, with small decreases simulated over Asia. Simulated isotopic anomalies agree well with proxy climate records, with lighter isotopic values simulated over South America and enriched values across East Asia. For this particular abrupt climate event, we identify which climatic change is most likely linked to water isotope change – changes in local precipitation amount, monsoon intensity, water vapour source distributions or precipitation seasonality. We categorise individual sites according to the climate variability that water isotope changes are most closely associated with, and find that the dominant isotopic controls are not consistent across the tropics – simple local explanations, in particular, fall short of explaining water isotope variability at all sites. Instead, the best interpretations appear to be site specific and often regional in scale.

  15. Vapour pressures, densities, and viscosities of the (water + lithium bromide + potassium acetate) system and (water + lithium bromide + sodium lactate) system

    International Nuclear Information System (INIS)

    Lucas, Antonio de; Donate, Marina; Rodriguez, Juan F.

    2006-01-01

    Measurements of thermophysical properties (vapour pressure, density, and viscosity) of the (water + lithium bromide + potassium acetate) system LiBr:CH 3 COOK = 2:1 by mass ratio and the (water + lithium bromide + sodium lactate) system LiBr:CH 3 CH(OH)COONa = 2:1 by mass ratio were measured. The system, a possible new working fluid for absorption heat pump, consists of absorbent (LiBr + CH 3 COOK) or (LiBr + CH 3 CH(OH)COONa) and refrigerant H 2 O. The vapour pressures were measured in the ranges of temperature and absorbent concentration from T = (293.15 to 333.15) K and from mass fraction 0.20 to 0.50, densities and viscosities were measured from T = (293.15 to 323.15) K and from mass fraction 0.20 to 0.40. The experimental data were correlated with an Antoine-type equation. Densities and viscosities were measured in the same range of temperature and absorbent concentration as that of the vapour pressure. Regression equations for densities and viscosities were obtained with a minimum mean square error criterion

  16. Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems

    DEFF Research Database (Denmark)

    Ibrom, Andreas; Dellwik, Ebba; Flyvbjerg, Henrik K.

    2007-01-01

    datasets for this substantial measurement error. In contrast to earlier studies, a large number of spectra and raw data have been used in the analysis to define the low-pass filtering characteristic of the EC system. This revealed that the cut-off frequency of the closed-path EC system for water vapour......Turbulent water vapour fluxes measured with closed-path eddy correlation (EC) systems are unintentionally low-pass filtered by the system in a manner that varies with environmental conditions. Why and how is described here. So is the practical method that systematically corrects long-term flux...... concentration measurements decreases exponentially with increasing relative humidity. After correction for this unintended filtering, the fluxes are consistent with CO2 and H2O fluxes that were measured with an open-path sensor at the same time. The correction of water vapour flux measurements over a Beech...

  17. Global distributions of water vapour isotopologues retrieved from IMG/ADEOS data

    Directory of Open Access Journals (Sweden)

    H. Herbin

    2007-07-01

    Full Text Available The isotopologic composition of water vapour in the atmosphere provides valuable information on many climate, chemical and dynamical processes. The accurate measurements of the water isotopologues by remote-sensing techniques remains a challenge, due to the large spatial and temporal variations. Simultaneous profile retrievals of the main water isotopologues (i.e. H216O, H218O and HDO and their ratios are presented here for the first time, along their retrieved global distributions. The results are obtained by exploiting the high resolution infrared spectra recorded by the Interferometric Monitor for Greenhouse gases (IMG instrument, which has operated in the nadir geometry onboard the ADEOS satellite between 1996 and 1997. The retrievals are performed on cloud-free radiances, measured during ten days of April 1997, considering two atmospheric windows (1205–1228 cm−1; 2004–2032 cm−1 and using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM. Characterizations in terms of vertical sensitivity and error budget are provided. We show that a relatively high vertical resolution is achieved for H216O (~4–5 km, and that the retrieved profiles are in fair agreement with local sonde measurements, at different latitudes. The retrieved global distributions of H216O, H218O, HDO and their ratios are presented and found to be consistent with previous experimental studies and models. The Ocean-Continent difference, the latitudinal and vertical dependence of the water vapour amount and the isotopologic depletion are notably well reproduced. Others trends, possibly related to small-scale variations in the vertical profiles are also discussed. Despite the difficulties encountered for computing accurately the isotopologic ratios, our results demonstrate the ability

  18. Evolution of stratospheric ozone and water vapour time series studied with satellite measurements

    Directory of Open Access Journals (Sweden)

    A. Jones

    2009-08-01

    Full Text Available The long term evolution of stratospheric ozone and water vapour has been investigated by extending satellite time series to April 2008. For ozone, we examine monthly average ozone values from various satellite data sets for nine latitude and altitude bins covering 60° S to 60° N and 20–45 km and covering the time period of 1979–2008. Data are from the Stratospheric Aerosol and Gas Experiment (SAGE I+II, the HALogen Occultation Experiment (HALOE, the Solar BackscatterUltraViolet-2 (SBUV/2 instrument, the Sub-Millimetre Radiometer (SMR, the Optical Spectrograph InfraRed Imager System (OSIRIS, and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY. Monthly ozone anomalies are calculated by utilising a linear regression model, which also models the solar, quasi-biennial oscillation (QBO, and seasonal cycle contributions. Individual instrument ozone anomalies are combined producing an all instrument average. Assuming a turning point of 1997 and that the all instrument average is represented by good instrumental long term stability, the largest statistically significant ozone declines (at two sigma from 1979–1997 are seen at the mid-latitudes between 35 and 45 km, namely −7.2%±0.9%/decade in the Northern Hemisphere and −7.1%±0.9%/in the Southern Hemisphere. Furthermore, for the period 1997 to 2008 we find that the same locations show the largest ozone recovery (+1.4% and +0.8%/decade respectively compared to other global regions, although the estimated trend model errors indicate that the trend estimates are not significantly different from a zero trend at the 2 sigma level. An all instrument average is also constructed from water vapour anomalies during 1991–2008, using the SAGE II, HALOE, SMR, and the Microwave Limb Sounder (Aura/MLS measurements. We report that the decrease in water vapour values after 2001 slows down around 2004–2005 in the lower tropical stratosphere (20–25 km and has even

  19. Near-infrared water vapour self-continuum at close to room temperature

    International Nuclear Information System (INIS)

    Ptashnik, I.V.; Petrova, T.M.; Ponomarev, Yu.N.; Shine, K.P.; Solodov, A.A.; Solodov, A.M.

    2013-01-01

    The gaseous absorption of solar radiation within near-infrared atmospheric windows in the Earth's atmosphere is dominated by the water vapour continuum. Recent measurements by Baranov et al. (2011) [17] in 2500 cm −1 (4 μm) window and by Ptashnik et al. (2011) [18] in a few near-infrared windows revealed that the self-continuum absorption is typically an order of magnitude stronger than given by the MT C KD continuum model prior to version 2.5. Most of these measurements, however, were made at elevated temperatures, which makes their application to atmospheric conditions difficult. Here we report new laboratory measurements of the self-continuum absorption at 289 and 318 K in the near-infrared spectral region 1300–8000 cm −1 , using a multipass 30 m base cell with total optical path 612 m. Our results confirm the main conclusions of the previous measurements both within bands and in windows. Of particular note is that we present what we believe to be the first near-room temperature measurement using Fourier Transform Spectrometry of the self-continuum in the 6200 cm −1 (1.6 μm) window, which provides tentative evidence that, at such temperatures, the water vapour continuum absorption may be as strong as it is in 2.1 μm and 4 μm windows and up to 2 orders of magnitude stronger than the MT C KD-2.5 continuum. We note that alternative methods of measuring the continuum in this window have yielded widely differing assessment of its strength, which emphasises the need for further measurements. -- Highlights: ► New lab measurements of the near-infrared water vapour self-continuum absorption. ► First room-temperature data on the self-continuum in the 1.6 μm window. ► In the 1.6 μm window the new data exceed MT C KD-2.5 model by 2 orders of magnitude

  20. The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour

    International Nuclear Information System (INIS)

    Scott, T.B.; Petherbridge, J.R.; Harker, N.J.; Ball, R.J.; Heard, P.J.; Glascott, J.; Allen, G.C.

    2011-01-01

    Highlights: → High resolution imagery (FIB, SEM and SIMS) of carbide inclusions in uranium metal. → Real time images following the reaction of the carbide inclusions with water vapour. → Shown preferential consumption of carbide over that of the bulk metal. → Quantity of impurities in the metal therefore seriously influence reaction rate. → Metal purity must be considered when storing uranium in air or moist conditions. - Abstract: The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO 3 .xH 2 O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets.

  1. ARSENIC REMOVAL FROM DRINKING WATER BY IRON REMOVAL PLANTS

    Science.gov (United States)

    This report documents a long term performance study of two iron removal water treatment plants to remove arsenic from drinking water sources. Performance information was collected from one system located in midwest for one full year and at the second system located in the farwest...

  2. Validation for a new apparatus measuring water vapour enhancement factors up to 6 MPa

    International Nuclear Information System (INIS)

    Sairanen, H; Heinonen, M

    2014-01-01

    High accuracy dew-point measurements require a water vapour enhancement factor to correct the effects of pressure drop in a sampling line. The enhancement factor is also needed when a humidity quantity value is converted to another. In this paper a new apparatus for traceable measurements of the enhancement factor is presented along with the results of validation measurements with air and methane. The apparatus is designed for dew-point temperatures from −50 to +15 °C and the pressure range from atmospheric pressure up to 6 MPa. The performance of the apparatus was investigated by comparing measurement results to the literature data for air and the data calculated from published thermodynamic measurement results for methane. It is shown that the experimental results agree with the reference data within the estimated uncertainties. (paper)

  3. The drift velocity of electrons in water vapour at low values of E/N

    International Nuclear Information System (INIS)

    Cheung, B.; Elford, M.T.

    1990-01-01

    The drift velocity of electrons in water vapour at 294 K has been measured over the E/N range 1.4 to 40 Td with an error estimated to be 35 Td. The present data show that μN decreases monotonically with decreasing E/N at low E/N values as observed by Wilson et al. (1975) and does not become independent of E/N as indicated by Lowke and Rees (1963). The present values although lower than those of Lowke and Rees, lie within the combined error limits, except for values below 2 Td. The present data suggested that the momentum transfer cross section at low energies is approximately 10% larger than that obtained by Pack et al. (1962) from their drift velocity measurements. 13 refs., 2 tabs., 5 figs

  4. The assessment of water vapour and carbon dioxide fluxes above arable crops - a comparison of methods

    Energy Technology Data Exchange (ETDEWEB)

    Schaaf, S.; Daemmgen, U.; Burkart, S. [Federal Agricultural Research Centre, Inst. of Agroecology, Braunschweig (Germany); Gruenhage, L. [Justus-Liebig-Univ., Inst. for Plant Ecology, Giessen (Germany)

    2005-04-01

    Vertical fluxes of water vapour and carbon dioxide obtained from gradient, eddy covariance (closed and open path systems) and chamber measurements above arable crops were compared with the directly measured energy balance and the harvested net biomass carbon. The gradient and chamber measurements were in the correct order of magnitude, whereas the closed path eddy covariance system showed unacceptably small fluxes. Correction methods based on power spectra analysis yielded increased fluxes. However, the energy balance could not be closed satisfactorily. The application of the open path system proved to be successful. The SVAT model PLATIN which had been adapted to various arable crops was able to depict the components of the energy balance adequately. Net carbon fluxes determined with the corrected closed path data sets, chamber, and SVAT model equal those of the harvested carbon. (orig.)

  5. PFS/Mars Express first results: water vapour and carbon monoxide global distribution

    Science.gov (United States)

    Ignatiev, N. I.; Titov, D. V.; Formisano, V.; Moroz, V. I.; Lellouch, E.; Encrenaz, Th.; Fouchet, T.; Grassi, D.; Giuranna, M.; Atreya, S.; Pfs Team

    Planetary Fourier Spectrometer onboard Mars Express, with its wide spectral range (1.2--45 um) and high spectral resolution (1.4 cm-1), makes it possible to study in a self-consistent manner the Martian atmosphere by means of simultaneous analysis of spectral features in several spectral regions. As concerned small species, we observe 30--50, 6.3, 2.56, 1.87 and 1.38 μ m H2O bands, and 4.7 and 2.35 μ m CO bands. The most favourable, with respect to the instrument performance, 2.56 μ m H2O and 4.7 μ m CO bands, are used to study the variations of column abundance of water vapour and carbon monoxide on a global scale from pole to pole. All necessary atmospheric parameters, namely temperature profiles, surface pressure, and dust density are obtained from the same spectra, whenever possible.

  6. Enhanced MODIS Atmospheric Total Water Vapour Content Trends in Response to Arctic Amplification

    Directory of Open Access Journals (Sweden)

    Dunya Alraddawi

    2017-12-01

    Full Text Available In order to assess the strength of the water vapour feedback within Arctic climate change, 15 years of the total column-integrated density of water vapour (TCWV from the moderate resolution imaging spectrometer (MODIS are analysed. Arctic TCWV distribution, trends, and anomalies for the 2001–2015 period, broken down into seasons and months, are analysed. Enhanced local spring TCWV trends above the terrestrial Arctic regions are discussed in relation to land snow cover and vegetation changes. Upward TCWV trends above the oceanic areas are discussed in lien with sea ice extent and sea surface temperature changes. Increased winter TCWV (up to 40% south of the Svalbard archipelago are observed; these trends are probably driven by a local warming and sea ice extent decline. Similarly, the Barents/Kara regions underwent wet trends (up to 40%, also associated with winter/fall local sea ice loss. Positive late summer TCWV trends above the western Greenland and Beaufort seas (about 20% result from enhanced upper ocean warming and thereby a local coastal decline in ice extent. The Mackenzie and Siberia enhanced TCWV trends (about 25% during spring are found to be associated with coincident decreased snow cover and increased vegetation, as a result of the earlier melt onset. Results show drier summers in the Eurasia and western Alaska regions, thought to be affected by changes in albedo from changing vegetation. Other TCWV anomalies are also presented and discussed in relation to the dramatic decline in sea ice extent and the exceptional rise in sea surface temperature.

  7. Influence of water vapour and permanent gases on the atmospheric optical depths and transmittance

    Science.gov (United States)

    Badescu, V.

    1991-05-01

    The influence of the atmospheric state on the extinction of direct solar radiation has been studied by using a four layer atmospheric model. Simple analytical formulae are established for the spectral optical depths of permanent gases and water vapour. These formulae use the ground level values of air pressure, temperature and relative huniidity. An additional parameter, related to the vertical distribution of the hunmidity content, is used for a better estimation of the water vapour optical depth. Good agreement between theory and measurements is found. The paper shows the dependence of the atmospheric spectral transmittance on the above mentioned parameters. L'influence de l'état atmosphérique sur l'extinction de la radiation solaire directe a été étudiée à l'aide d'un modèle atmosphérique développé antérieurement par l'auteur. Des formules simples ont été établies pour l'épaisseur optique spectrale des gaz et de la vapeur d'eau. Ces formules utilisent les valeurs de la pression atmosphérique, de la température et de l'humidité relative, mesurées au niveau du sol. Un paramètre supplémentaire, lié à la distribution verticale du contenu d'humidité, est utilisé pour calculer l'épaisseur optique due à la vapeur d'eau. La théorie est en bon accord avec les résultats des mesures. Le travail montre la dépendance de la transmittance atmosphérique spectrale en fonction des paramètres spécifiés ci-dessus.

  8. Soil-water characteristics of Gaomiaozi bentonite by vapour equilibrium technique

    Directory of Open Access Journals (Sweden)

    Wenjing Sun

    2014-02-01

    Full Text Available Soil-water characteristics of Gaomiaozi (GMZ Ca-bentonite at high suctions (3–287 MPa are measured by vapour equilibrium technique. The soil-water retention curve (SWRC of samples with the same initial compaction states is obtained in drying and wetting process. At high suctions, the hysteresis behaviour is not obvious in relationship between water content and suction, while the opposite holds between degree of saturation and suction. The suction variation can change its water retention behaviour and void ratio. Moreover, changes of void ratio can bring about changes in degree of saturation. Therefore, the total change in degree of saturation includes changes caused by suction and that by void ratio. In the space of degree of saturation and suction, the SWRC at constant void ratio shifts to the direction of higher suctions with decreasing void ratio. However, the relationship between water content and suction is less affected by changes of void ratio. The degree of saturation decreases approximately linearly with increasing void ratio at a constant suction. Moreover, the slope of the line decreases with increasing suction and they show an approximately linear relationship in semi-logarithmical scale. From this linear relationship, the variation of degree of saturation caused by the change in void ratio can be obtained. Correspondingly, SWRC at a constant void ratio can be determined from SWRC at different void ratios.

  9. Transport mechanisms through PE-CVD coatings: influence of temperature, coating properties and defects on permeation of water vapour

    International Nuclear Information System (INIS)

    Kirchheim, Dennis; Jaritz, Montgomery; Hopmann, Christian; Dahlmann, Rainer; Mitschker, Felix; Awakowicz, Peter; Gebhard, Maximilian; Devi, Anjana; Brochhagen, Markus; Böke, Marc

    2017-01-01

    Gas transport mechanisms through plastics are usually described by the temperature-dependent Arrhenius-model and compositions of several plastic layers are represented by the CLT. When it comes to thin films such as plasma-enhanced chemical vapour deposition (PE-CVD) or plasma-enhanced atomic layer deposition (PE-ALD) coatings on substrates of polymeric material, a universal model is lacking. While existing models describe diffusion through defects, these models presume that permeation does not occur by other means of transport mechanisms. This paper correlates the existing transport models with data from water vapour transmission experiments. (paper)

  10. Vapour explosions (fuel-coolant interactions) resulting from the sub-surface injection of water into molten metals: preliminary results

    International Nuclear Information System (INIS)

    Asher, R.C.; Bullen, D.; Davies, D.

    1976-03-01

    Preliminary experiments are reported on the relationship between the injection mode of contact and the occurrence and magnitude of vapour explosions. Water was injected beneath the surface of molten metals, chiefly tin at 250 to 900 0 C. Vapour explosions occurred in many, but not all, cases. The results are compared with Dullforce's observations (Culham Report (CLM-P424) on the dropping mode of contact and it appears that rather different behaviour is found; in particular, the present results suggest that the Temperature Interaction Zone is different for the two modes of contact. (author)

  11. Application of cylinder symmetry to iron and titanium oxidation by oxygen or hydrogen-water vapour mixes

    International Nuclear Information System (INIS)

    Raynaud, Pierre

    1980-01-01

    This research thesis addresses the study of the oxidation reaction in the case of corrosion of iron by oxygen, hydrogen sulphide or hydrogen-water vapour mixes, and in the case of oxidation of titanium and of titanium nitride by hydrogen-water vapour mixes. It first addresses the corrosion of iron by oxygen with an experiment performed in cylinder symmetry: description of operational conditions, discussion of kinetic curves, development of a law of generation of multiple layers in cylinder symmetry, analytical exploitation of experimental results. The second part addresses the oxidation of iron by hydrogen-water vapour mixes: experimental conditions, influence of temperature on kinetics, micrographic study (oxide morphology, coating morphology, interpretation of differences with the case of plane symmetry), discussion of the influence of cylinder symmetry on oxidation kinetics. The third part addresses the oxidation of titanium by hydrogen-water vapour mixes: global kinetic evolution, reaction products and micrographic examination, morphology and texture studies, discussion of the oxidation mechanism and of cylinder symmetry [fr

  12. Investigating the Interaction of Water Vapour with Aminopropyl Groups on the Surface of Mesoporous Silica Nanoparticles.

    Science.gov (United States)

    Paul, Geo; Musso, Giorgia Elena; Bottinelli, Emanuela; Cossi, Maurizio; Marchese, Leonardo; Berlier, Gloria

    2017-04-05

    The interaction of water molecules with the surface of hybrid silica-based mesoporous materials is studied by 29 Si, 1 H and 13 C solid-state NMR and IR spectroscopy, with the support of ab initio calculations. The surface of aminopropyl-grafted mesoporous silica nanoparticles is studied in the dehydrated state and upon interaction with controlled doses of water vapour. Former investigations described the interactions between aminopropyl and residual SiOH groups; the present study shows the presence of hydrogen-bonded species (SiOH to NH 2 ) and weakly interacting "free" aminopropyl chains with restricted mobility, together with a small amount of protonated NH 3 + groups. The concentration of the last-named species increased upon interaction with water, and this indicates reversible and fast proton exchange from water molecules to a fraction of the amino groups. Herein, this is discussed and explained for the first time, by a combination of experimental and theoretical approaches. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Experimental Investigation of a Mechanical Vapour Compression Chiller at Elevated Chilled Water Temperatures

    KAUST Repository

    Thu, Kyaw

    2017-05-18

    The performance of a Mechanical Vapour Compression (MVC) chiller is experimentally investigated under operating conditions suitable for sensible cooling. With the emergence of the energy efficient dehumidification systems, it is possible to decouple the latent load from the MVC chillers which can be operated at higher chilled water temperature for handling sensible cooling load. In this article, the performance of the chiller is evaluated at the elevated chilled water outlet temperatures (7 – 17° C) at various coolant temperatures (28 – 32° C) and flow rates (ΔT = 4 and 5° C) for both full- and part-load conditions. Keeping the performance at the AHRI standard as the baseline condition, the efficacy of the chiller in terms of compression ratio, cooling capacity and COP at aforementioned conditions is quantified experimentally. It is observed that for each one-degree Celsius increase in the chilled water temperature, the COP of the chiller improves by about 3.5% whilst the cooling capacity improvement is about 4%. For operation at 17° C chilled water outlet temperature, the improvements in COP and cooling capacity are between 37 – 40% and 40 – 45%, respectively, compared to the performance at the AHRI standards. The performance of the MVC chiller at the abovementioned operation conditions is mapped on the chiller performance characteristic chart.

  14. Experimental Investigation of a Mechanical Vapour Compression Chiller at Elevated Chilled Water Temperatures

    KAUST Repository

    Thu, Kyaw; Saththasivam, Jayaprakash; Saha, Bidyut Baran; Chua, Kian Jon; Srinivasa Murthy, S.; Ng, Kim Choon

    2017-01-01

    The performance of a Mechanical Vapour Compression (MVC) chiller is experimentally investigated under operating conditions suitable for sensible cooling. With the emergence of the energy efficient dehumidification systems, it is possible to decouple the latent load from the MVC chillers which can be operated at higher chilled water temperature for handling sensible cooling load. In this article, the performance of the chiller is evaluated at the elevated chilled water outlet temperatures (7 – 17° C) at various coolant temperatures (28 – 32° C) and flow rates (ΔT = 4 and 5° C) for both full- and part-load conditions. Keeping the performance at the AHRI standard as the baseline condition, the efficacy of the chiller in terms of compression ratio, cooling capacity and COP at aforementioned conditions is quantified experimentally. It is observed that for each one-degree Celsius increase in the chilled water temperature, the COP of the chiller improves by about 3.5% whilst the cooling capacity improvement is about 4%. For operation at 17° C chilled water outlet temperature, the improvements in COP and cooling capacity are between 37 – 40% and 40 – 45%, respectively, compared to the performance at the AHRI standards. The performance of the MVC chiller at the abovementioned operation conditions is mapped on the chiller performance characteristic chart.

  15. Laser removal of water repellent treatments on limestone

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Heras, Miguel; Alvarez de Buergo, Monica; Rebollar, Esther; Oujja, Mohamed; Castillejo, Marta; Fort, Rafael

    2003-12-15

    Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

  16. PRTR ion exchange vault water removal

    International Nuclear Information System (INIS)

    Ham, J.E.

    1995-11-01

    This report documents the removal of radiologically contaminated water from the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. Approximately 57,000 liters (15,000 gallons) of water had accumulated in the vault due to the absence of a rain cover. The water was removed and the vault inspected for signs of leakage. No evidence of leakage was found. The removal and disposal of the radiologically contaminated water decreased the risk of environmental contamination

  17. Analysing the mechanisms of soil water and vapour transport in the desert vadose zone of the extremely arid region of northern China

    Science.gov (United States)

    Du, Chaoyang; Yu, Jingjie; Wang, Ping; Zhang, Yichi

    2018-03-01

    The transport of water and vapour in the desert vadose zone plays a critical role in the overall water and energy balances of near-surface environments in arid regions. However, field measurements in extremely dry environments face many difficulties and challenges, so few studies have examined water and vapour transport processes in the desert vadose zone. The main objective of this study is to analyse the mechanisms of soil water and vapour transport in the desert vadose zone (depth of ∼350 cm) by using measured and modelled data in an extremely arid environment. The field experiments are implemented in an area of the Gobi desert in northwestern China to measure the soil properties, daily soil moisture and temperature, daily water-table depth and temperature, and daily meteorological records from DOYs (Days of Year) 114-212 in 2014 (growing season). The Hydrus-1D model, which simulates the coupled transport of water, vapour and heat in the vadose zone, is employed to simulate the layered soil moisture and temperature regimes and analyse the transport processes of soil water and vapour. The measured results show that the soil water and temperatures near the land surface have visible daily fluctuations across the entire soil profile. Thermal vapour movement is the most important component of the total water flux and the soil temperature gradient is the major driving factor that affects vapour transport in the desert vadose zone. The most active water and heat exchange occurs in the upper soil layer (depths of 0-25 cm). The matric potential change from the precipitation mainly re-draws the spatio-temporal distribution of the isothermal liquid water in the soil near the land surface. The matric potential has little effect on the isothermal vapour and thermal liquid water flux. These findings offer new insights into the liquid water and vapour movement processes in the extremely arid environment.

  18. Daily variations of delta 18O and delta D in daily samplings of air water vapour and rain water in the Amazon Basin

    International Nuclear Information System (INIS)

    Matsui, E.; Salati, E.; Ribeiro, M.N.G.; Tancredi, A.C.F.N.S.; Reis, C.M. dos

    1984-01-01

    The movement of rain water in the soil from 0 to 120 cm depth using delta 18 O weekly variations is studied. A study of the delta D variability in water vapour and rain water samples during precipitation was also done, the samples being collected a 3 minute intervals from the beginning to the end of precipitation. (M.A.C.) [pt

  19. Response of water vapour D-excess to land-atmosphere interactions in a semi-arid environment

    KAUST Repository

    Parkes, Stephen

    2016-06-30

    The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (dv). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (dET) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime dv values. The low dET observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime dv and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime dv variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of dv values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate dET can generally be expected to show

  20. THE REMOVAL OF GLYPHOSATE FROM DRINKING WATER

    Science.gov (United States)

    The effectiveness of granulated activated carbon (GAC), packed activated carbon (PAC), conventional treatment, membranes, and oxidation for removing glyphosate from natural waters is evaluated. Results indicate that GAC and PAC are not effective in removing glyphosate, while oxid...

  1. ADSORPTIVE REMOVAL OF FLUORIDE FROM WATER USING ...

    African Journals Online (AJOL)

    Preferred Customer

    Currently available treatment methods for removal of excess fluoride from water are broadly divided into three ... the application of nanoparticles as sorbents for fluoride removal. Sundaram [26] studied the ... Characterization of adsorbent.

  2. Tritium gas and tritiated water vapour behaviour in the environment from releases into the atmosphere from fusion reactors

    International Nuclear Information System (INIS)

    Velarde, Marta; Perlado, Manuel

    2001-01-01

    The diffusion of tritium from fusion reactors follows different ways according to the present chemical form, tritium gas or tritiated water vapour. The atmospheric conditions, speed and direction of the wind, rain intensity or stability class, are key factors in the dry and wet deposition. The obtained results demonstrate that the wet deposition is critical for the incorporation of the tritiated water vapour to the natural biological chain. However, the dry deposition is the factor that influences in the tritium gas form. The conversion of HT into HTO in the soil is rapid (1-7 days), and 20% of HT deposited in the soil is reemitted to the atmosphere in the form HTO, while the rest incorporates into the biological cycle. The rain factor accelerates the incorporation of tritium to the ground, the superficial waters and the underground waters

  3. The vapour pressure of water as a function of solute concentration above aqueous solutions of fructose, sucrose, raffinose, erythritol, xylitol, and sorbitol

    DEFF Research Database (Denmark)

    Cooke, S.A.; Jonsdottir, Svava Osk; Westh, Peter

    2002-01-01

    The vapour pressure of water above an aqueous solution of sucrose at T = 298.06 K has been measured for 9 sucrose mole fractions up to 0.12. Vapour pressure measurements have also been made on aqueous solutions of meso-erythritol, xylitol, sorbitol, fructose, and raffinose at T = 317.99 K...

  4. 49 CFR 193.2173 - Water removal.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Water removal. 193.2173 Section 193.2173...: FEDERAL SAFETY STANDARDS Design Impoundment Design and Capacity § 193.2173 Water removal. (a) Impoundment areas must be constructed such that all areas drain completely to prevent water collection. Drainage...

  5. Liquid and vapour water transfer through whey protein/lipid emulsion films.

    Science.gov (United States)

    Kokoszka, Sabina; Debeaufort, Frederic; Lenart, Andrzej; Voilley, Andree

    2010-08-15

    Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films. Films were cast from heated (80 degrees C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg(-1) of water) containing glycerol (50 g kg(-1) of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light-scattering granulometry, differential scanning calorimetry, wetting properties and water vapour permeability (WVP) were made. The emulsion structure in the film suspension changed significantly during drying, with oil creaming and coalescence occurring. Increasing oil concentration led to a 2.5-fold increase in surface hydrophobicity and decreases in WVP and denaturation temperature (T(max)). Film structure and surface properties explain the moisture absorption and film swelling as a function of moisture level and time and consequently the WVP behaviour. Small amounts of rapeseed oil favourably affect the WVP of WPI films, particularly at higher humidities. Copyright (c) 2010 Society of Chemical Industry.

  6. Comparison of total water vapour content in the Arctic derived from GNSS, AIRS, MODIS and SCIAMACHY

    Science.gov (United States)

    Alraddawi, Dunya; Sarkissian, Alain; Keckhut, Philippe; Bock, Olivier; Noël, Stefan; Bekki, Slimane; Irbah, Abdenour; Meftah, Mustapha; Claud, Chantal

    2018-05-01

    Atmospheric water vapour plays a key role in the Arctic radiation budget, hydrological cycle and hence climate, but its measurement with high accuracy remains an important challenge. Total column water vapour (TCWV) datasets derived from ground-based GNSS measurements are used to assess the quality of different existing satellite TCWV datasets, namely from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Atmospheric Infrared Sounder (AIRS) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). The comparisons between GNSS and satellite data are carried out for three reference Arctic observation sites (Sodankylä, Ny-Ålesund and Thule) where long homogeneous GNSS time series of more than a decade (2001-2014) are available. We select hourly GNSS data that are coincident with overpasses of the different satellites over the three sites and then average them into monthly means that are compared with monthly mean satellite products for different seasons. The agreement between GNSS and satellite time series is generally within 5 % at all sites for most conditions. The weakest correlations are found during summer. Among all the satellite data, AIRS shows the best agreement with GNSS time series, though AIRS TCWV is often slightly too high in drier atmospheres (i.e. high-latitude stations during autumn and winter). SCIAMACHY TCWV data are generally drier than GNSS measurements at all the stations during the summer. This study suggests that these biases are associated with cloud cover, especially at Ny-Ålesund and Thule. The dry biases of MODIS and SCIAMACHY observations are most pronounced at Sodankylä during the snow season (from October to March). Regarding SCIAMACHY, this bias is possibly linked to the fact that the SCIAMACHY TCWV retrieval does not take accurately into account the variations in surface albedo, notably in the presence of snow with a nearby canopy as in Sodankylä. The MODIS bias at Sodankylä is found

  7. X-ray photoelectron spectroscopy study of the initial oxidation of uranium metal in oxygen+water-vapour mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Allen, G.C.; Tucker, P.M.; Lewis, R.A. (Central Electricity Generating Board, Berkeley (UK). Berkeley Nuclear Labs.)

    1984-08-01

    X-ray photoelectron spectroscopy (X.p.s.) has been used to study the chemical nature of the oxide film initially produced on clean uranium metal in oxygen + water-vapour atmospheres. The rate of reaction has been monitored and the nature of the surface film determined. From a consideration of the O 1s and U 4f X.p. spectra it has been possible to advance a mechanism which explains the complex nature of the surface oxide and the lack of satellite structure in the spectra. This is postulated to be a consequence of the way in which OH/sup -/ is involved in the growth of the oxide and the presence of hydrogen in the surface film. The presence of oxygen retards the water oxidation reaction by inhibiting the decomposition of water vapour at the gas/oxide interface.

  8. X-ray photoelectron spectroscopy study of the initial oxidation of uranium metal in oxygen+water-vapour mixtures

    International Nuclear Information System (INIS)

    Allen, G.C.; Tucker, P.M.; Lewis, R.A.

    1984-01-01

    X-ray photoelectron spectroscopy (X.p.s.) has been used to study the chemical nature of the oxide film initially produced on clean uranium metal in oxygen + water-vapour atmospheres. The rate of reaction has been monitored and the nature of the surface film determined. From a consideration of the O 1s and U 4f X.p. spectra it has been possible to advance a mechanism which explains the complex nature of the surface oxide and the lack of satellite structure in the spectra. This is postulated to be a consequence of the way in which OH - is involved in the growth of the oxide and the presence of hydrogen in the surface film. The presence of oxygen retards the water oxidation reaction by inhibiting the decomposition of water vapour at the gas/oxide interface. (author)

  9. The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour.

    Science.gov (United States)

    Scott, T B; Petherbridge, J R; Harker, N J; Ball, R J; Heard, P J; Glascott, J; Allen, G C

    2011-11-15

    The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO(3) · xH(2)O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  10. Validation of near infrared satellite based algorithms to relative atmospheric water vapour content over land

    International Nuclear Information System (INIS)

    Serpolla, A.; Bonafoni, S.; Basili, P.; Biondi, R.; Arino, O.

    2009-01-01

    This paper presents the validation results of ENVISAT MERIS and TERRA MODIS retrieval algorithms for atmospheric Water Vapour Content (WVC) estimation in clear sky condition on land. The MERIS algorithms exploits the radiance ratio of the absorbing channel at 900 nm with the almost absorption-free reference at 890 nm, while the MODIS one is based on the ratio of measurements centred at near 0.905, 0.936, and 0.94 μm with atmospheric window reflectance at 0.865 and 1.24 μm. The first test was performed in the Mediterranean area using WVC provided from both ECMWF and AERONET. As a second step, the performances of the algorithms were tested exploiting WVC computed from radio sounding (RAOBs)in the North East Australia. The different comparisons with respect to reference WVC values showed an overestimation of WVC by MODIS (root mean square error percentage greater than 20%) and an acceptable performance of MERIS algorithms (root mean square error percentage around 10%) [it

  11. Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour.

    Science.gov (United States)

    Nagai, Masatsugu; Nakanishi, Kazuhiro; Takahashi, Hiraku; Kato, Hiromitsu; Makino, Toshiharu; Yamasaki, Satoshi; Matsumoto, Tsubasa; Inokuma, Takao; Tokuda, Norio

    2018-04-27

    Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

  12. Influence of chemisorption products of carbon dioxide and water vapour on radiolysis of tritium breeder

    Energy Technology Data Exchange (ETDEWEB)

    Zarins, Arturs, E-mail: arturs.zarins@lu.lv [University of Latvia, Institute of Chemical Physics, Kronvalda Boulevard 4, LV-1010 Riga (Latvia); Kizane, Gunta; Supe, Arnis [University of Latvia, Institute of Chemical Physics, Kronvalda Boulevard 4, LV-1010 Riga (Latvia); Knitter, Regina; Kolb, Matthias H.H. [Karlsruhe Institute of Technology, Institute for Applied Materials (IAM-WPT), 76021 Karlsruhe (Germany); Tiliks, Juris; Baumane, Larisa [University of Latvia, Institute of Chemical Physics, Kronvalda Boulevard 4, LV-1010 Riga (Latvia)

    2014-10-15

    Highlights: • Chemisorption products affect formation proceses of radiation-induced defects. • Radiolysis of chemisorption products increase amount of radiation-induced defects. • Irradiation atmosphere influence radiolysis of lithium orthosilicate pebbles. - Abstract: Lithium orthosilicate pebbles with 2.5 wt% excess of silica are the reference tritium breeding material for the European solid breeder test blanket modules. On the surface of the pebbles chemisorption products of carbon dioxide and water vapour (lithium carbonate and hydroxide) may accumulate during the fabrication process. In this study the influence of the chemisorption products on radiolysis of the pebbles was investigated. Using nanosized lithium orthosilicate powders, factors, which can influence the formation and radiolysis of the chemisorption products, were determined and described as well. The formation of radiation-induced defects and radiolysis products was studied with electron spin resonance and the method of chemical scavengers. It was found that the radiolysis of the chemisorption products on the surface of the pebbles can increase the concentration of radiation-induced defects and so could affect the tritium diffusion, retention and the released species.

  13. Analysis of global water vapour trends from satellite measurements in the visible spectral range

    Directory of Open Access Journals (Sweden)

    S. Mieruch

    2008-02-01

    Full Text Available Global water vapour total column amounts have been retrieved from spectral data provided by the Global Ozone Monitoring Experiment (GOME flying on ERS-2, which was launched in April 1995, and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY onboard ENVISAT launched in March 2002. For this purpose the Air Mass Corrected Differential Optical Absorption Spectroscopy (AMC-DOAS approach has been used. The combination of the data from both instruments provides us with a long-term global data set spanning more than 11 years with the potential of extension up to 2020 by GOME-2 data on MetOp.

    Using linear and non-linear methods from time series analysis and standard statistics the trends of H2O columns and their errors have been calculated. In this study, factors affecting the trend such as the length of the time series, the magnitude of the variability of the noise, and the autocorrelation of the noise are investigated. Special emphasis has been placed on the calculation of the statistical significance of the observed trends, which reveal significant local changes from −5% per year to +5% per year. These significant trends are distributed over the whole globe. Increasing trends have been calculated for Greenland, East Europe, Siberia and Oceania, whereas decreasing trends have been observed for the northwest USA, Central America, Amazonia, Central Africa and the Arabian Peninsular.

  14. Water vapour tomography using GPS phase observations: Results from the ESCOMPTE experiment

    Science.gov (United States)

    Nilsson, T.; Gradinarsky, L.; Elgered, G.

    2007-10-01

    Global Positioning System (GPS) tomography is a technique for estimating the 3-D structure of the atmospheric water vapour using data from a dense local network of GPS receivers. Several current methods utilize estimates of slant wet delays between the GPS satellites and the receivers on the ground, which are difficult to obtain with millimetre accuracy from the GPS observations. We present results of applying a new tomographic method to GPS data from the Expériance sur site pour contraindre les modèles de pollution atmosphérique et de transport d'emissions (ESCOMPTE) experiment in southern France. This method does not rely on any slant wet delay estimates, instead it uses the GPS phase observations directly. We show that the estimated wet refractivity profiles estimated by this method is on the same accuracy level or better compared to other tomographic methods. The results are in agreement with earlier simulations, for example the profile information is limited above 4 km.

  15. Effects of SO2 oxidation on ambient aerosol growth in water and ethanol vapours

    Directory of Open Access Journals (Sweden)

    T. Petäjä

    2005-01-01

    Full Text Available Hygroscopicity (i.e. water vapour affinity of atmospheric aerosol particles is one of the key factors in defining their impacts on climate. Condensation of sulphuric acid onto less hygroscopic particles is expected to increase their hygrocopicity and hence their cloud condensation nuclei formation potential. In this study, differences in the hygroscopic and ethanol uptake properties of ultrafine aerosol particles in the Arctic air masses with a different exposure to anthropogenic sulfur pollution were examined. The main discovery was that Aitken mode particles having been exposed to polluted air were more hygroscopic and less soluble to ethanol than after transport in clean air. This aging process was attributed to sulphur dioxide oxidation and subsequent condensation during the transport of these particle to our measurement site. The hygroscopicity of nucleation mode aerosol particles, on the other hand, was approximately the same in all the cases, being indicative of a relatively similar chemical composition despite the differences in air mass transport routes. These particles had also been produced closer to the observation site typically 3–8 h prior to sampling. Apparently, these particles did not have an opportunity to accumulate sulphuric acid on their way to the site, but instead their chemical composition (hygroscopicity and ethanol solubility resembled that of particles produced in the local or semi-regional ambient conditions.

  16. A lidar for water vapour measurements in daytime at Lampedusa, Italy

    Directory of Open Access Journals (Sweden)

    F. Marenco

    2003-06-01

    Full Text Available ENEA is planning to develop a lidar system for measurement of the vertical profi le of water vapour mixing ratio in daytime at a remote site, the Station for Climate Observations located in Lampedusa, Italy. The Raman lidar technique has been retained because of its experimental simplicity with respect to DIAL, and the UV spectral range has been chosen because Raman cross-sections and detector effi ciencies are larger. For a wavelength larger than ~ 300 nm the signal is limited in daytime by sky background, but extinction is acceptable, and the aims of the system can be reached with a strong laser source. The 355 nm wavelength of a frequency-tripled Nd:YAG laser has been retained as this laser source permits to reach a large pulse energy while keeping the system simple to operate. Geometrical form factor calculations need to be performed to evaluate the near-range overlap between the laser beam and the fi eld-of-view of the receiver. Among several options, a dual-receiver system has been retained to account for the several orders of magnitude expected in the backscattered signal intensity: a smaller receiver, with a primary mirror of 200 mm diameter for the 0.2-1 km range, and a larger 500 mm receiver for the 1-3 km range.

  17. RDF gasification with water vapour: influence of process temperature on yield and products composition

    International Nuclear Information System (INIS)

    Galvagno, S.; Casciaro, G.; Russo, A.; Casu, S.; Martino, M.; Portofino, S.

    2005-01-01

    The opportunity of using RDF (Refused Derived Fuel) to produce fuel gas seems to be promising and particular attention has been focused on alternative process technologies such as pyrolysis and gasification. Within this frame, present work relates to experimental tests and obtained results of a series of experimental surveys on RDF gasification with water vapour, carried out by means of a bench scale rotary kiln plant at different process temperature, using thermogravimetry (TG) and infrared spectrometry (FTIR), in order to characterize the incoming material, and online gas chromatography to qualify the gaseous stream. Experimental data show that gas yield rise with temperature and, with respect to the gas composition, hydrogen content grows up mainly at the expense of the other gaseous compound, pointing out the major extension of secondary cracking reactions into the gaseous fraction at higher temperature. Syngas obtained at process temperature of 950 o C or higher seems to be suitable for fuel cells applications; at lower process temperature, gas composition suggest a final utilisation for feedstock recycling. The low organic content of solid residue does not suggest any other exploitation of the char apart from the land filling [it

  18. Water Vapour Propulsion Powered by a High-Power Laser-Diode

    Science.gov (United States)

    Minami, Y.; Uchida, S.

    Most of the laser propulsion schemes now being proposed and developed assume neither power supplies nor on-board laser devices and therefore are bound to remote laser stations like a kite via a laser beam “string”. This is a fatal disadvantage for a space vehicle that flies freely though it is often said that no need of installing an energy source is an advantage of a laser propulsion scheme. The possibility of an independent laser propulsion space vehicle that carries a laser source and a power supply on board is discussed. This is mainly due to the latest development of high power laser diode (LD) technology. Both high specific impulse-low thrust mode and high thrust-low specific impulse mode can be selected by controlling the laser output by using vapour or water as a propellant. This mode change can be performed by switching between a high power continuous wave (cw), LD engine for high thrust with a low specific impulse mode and high power LD pumping Q-switched Nd:YAG laser engine for low thrust with the high specific impulse mode. This paper describes an Orbital Transfer Vehicle equipped with the above-mentioned laser engine system and fuel cell that flies to the Moon from a space platform or space hotel in Earth orbit, with cargo shipment from lunar orbit to the surface of the Moon, including the possibility of a sightseeing trip.

  19. Effect of alkanolammonium formates ionic liquids on vapour liquid equilibria of binary systems containing water, methanol, and ethanol

    International Nuclear Information System (INIS)

    Li Xuemei; Shen Chong; Li Chunxi

    2012-01-01

    Highlights ► Vapour pressures for six ternary systems containing an IL were measured. ► Components studied were water, ethanol, methanol, and alkanolammonium formates. ► The isobaric VLE were predicted using the fitted binary NRTL parameters. ► The ILs studied can generate a promising salt effect on VLE of azeotrope. ► [HMEA][HCOO] might be used as a potential entrainer in extractive distillation. - Abstract: Vapour pressures were measured using a quasi-static ebulliometer for the pseudo-binary mixtures of (water + ethanol), (water + methanol), and (methanol + ethanol) containing an alkanolammonium-based ionic liquid (IL), namely, mono-ethanolammonium formate ([HMEA][HCOO]) and di-ethanolammonium formate ([HDEA][HCOO]), respectively, with fixed IL mass fraction of 0.30 and over the temperature ranges of (292.12 to 371.13) K. The vapour pressures of the IL-containing ternary systems were favourably correlated using the NRTL model with an overall average absolute relative deviation (AARD) of 0.0082. Further, the salt effects of [HMEA][HCOO] and [HDEA][HCOO] on isobaric vapour liquid equilibria (VLE) of azeotrope and close boiling mixture, especially for the mixtures of (water + ethanol) and (methanol + ethanol), were investigated and compared with other ILs in terms of the x′–y phase diagrams predicted with the binary NRTL parameters. It is demonstrated that the relative volatilities of ethanol to water and ethanol to methanol are enhanced, and [HMEA][HCOO] might be used as a promising entrainer for the efficient separation of ethanol aqueous solution by special rectification.

  20. Ground-based remote sensing of tropospheric water vapour isotopologues within the project MUSICA

    Directory of Open Access Journals (Sweden)

    M. Schneider

    2012-12-01

    Full Text Available Within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water, long-term tropospheric water vapour isotopologue data records are provided for ten globally distributed ground-based mid-infrared remote sensing stations of the NDACC (Network for the Detection of Atmospheric Composition Change. We present a new method allowing for an extensive and straightforward characterisation of the complex nature of such isotopologue remote sensing datasets. We demonstrate that the MUSICA humidity profiles are representative for most of the troposphere with a vertical resolution ranging from about 2 km (in the lower troposphere to 8 km (in the upper troposphere and with an estimated precision of better than 10%. We find that the sensitivity with respect to the isotopologue composition is limited to the lower and middle troposphere, whereby we estimate a precision of about 30‰ for the ratio between the two isotopologues HD16O and H216O. The measurement noise, the applied atmospheric temperature profiles, the uncertainty in the spectral baseline, and the cross-dependence on humidity are the leading error sources. We introduce an a posteriori correction method of the cross-dependence on humidity, and we recommend applying it to isotopologue ratio remote sensing datasets in general. In addition, we present mid-infrared CO2 retrievals and use them for demonstrating the MUSICA network-wide data consistency. In order to indicate the potential of long-term isotopologue remote sensing data if provided with a well-documented quality, we present a climatology and compare it to simulations of an isotope incorporated AGCM (Atmospheric General Circulation Model. We identify differences in the multi-year mean and seasonal cycles that significantly exceed the estimated errors, thereby indicating deficits in the modeled atmospheric water cycle.

  1. Ground-based remote sensing of tropospheric water vapour isotopologues within the project MUSICA

    Science.gov (United States)

    Schneider, M.; Barthlott, S.; Hase, F.; González, Y.; Yoshimura, K.; García, O. E.; Sepúlveda, E.; Gomez-Pelaez, A.; Gisi, M.; Kohlhepp, R.; Dohe, S.; Blumenstock, T.; Wiegele, A.; Christner, E.; Strong, K.; Weaver, D.; Palm, M.; Deutscher, N. M.; Warneke, T.; Notholt, J.; Lejeune, B.; Demoulin, P.; Jones, N.; Griffith, D. W. T.; Smale, D.; Robinson, J.

    2012-12-01

    Within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water), long-term tropospheric water vapour isotopologue data records are provided for ten globally distributed ground-based mid-infrared remote sensing stations of the NDACC (Network for the Detection of Atmospheric Composition Change). We present a new method allowing for an extensive and straightforward characterisation of the complex nature of such isotopologue remote sensing datasets. We demonstrate that the MUSICA humidity profiles are representative for most of the troposphere with a vertical resolution ranging from about 2 km (in the lower troposphere) to 8 km (in the upper troposphere) and with an estimated precision of better than 10%. We find that the sensitivity with respect to the isotopologue composition is limited to the lower and middle troposphere, whereby we estimate a precision of about 30‰ for the ratio between the two isotopologues HD16O and H216O. The measurement noise, the applied atmospheric temperature profiles, the uncertainty in the spectral baseline, and the cross-dependence on humidity are the leading error sources. We introduce an a posteriori correction method of the cross-dependence on humidity, and we recommend applying it to isotopologue ratio remote sensing datasets in general. In addition, we present mid-infrared CO2 retrievals and use them for demonstrating the MUSICA network-wide data consistency. In order to indicate the potential of long-term isotopologue remote sensing data if provided with a well-documented quality, we present a climatology and compare it to simulations of an isotope incorporated AGCM (Atmospheric General Circulation Model). We identify differences in the multi-year mean and seasonal cycles that significantly exceed the estimated errors, thereby indicating deficits in the modeled atmospheric water cycle.

  2. Removal of radionuclides from household water

    International Nuclear Information System (INIS)

    Vesterbacka, P.; Turtiainen, T.; Haemaelaeinen, K.; Salonen, L.; Arvela, H.

    2003-10-01

    Research upon methods for removing radionuclides from household water was initiated in Finland in 1995. Three research projects, of which two were carried out with National Technology Agency of Finland and one with CEC, have been completed by the end of 2002. One of the main objectives of the research was to compose a guidebook for consumers and water treatment companies. Radon can be removed from household water by aeration and by activated carbon filtration. Aerators that are well designed and set up can remove over 90% of waterborne radon. The best aerators have achieved removal efficiencies that are nearly 100%. However, setting up an aeration system requires thorough planning. Also, activated carbon filtration removes radon efficiently. The removal efficiencies have been over 90%, often nearly 100%. Depending on the water quality and usage, the carbon batch inside the filter needs to be changed every 2-3 years. Since activated carbon filters emit gamma radiation while in use, they should not be installed inside the dwelling but in a separate building or by the well. It is recommended that uranium be removed from drinking water by anion exchange, which is the most efficient removal method for this purpose. Typically, the removal efficiencies are nearly 100%. The one exception is the so called tap filter, the removal efficiency of which depends on uranium concentration in raw water and the rate of water flow. High saline concentration in water may extricate uranium from ion exchange resin. Changes in plumbing pressure or pH-value do not have any significant influence in uranium retention. Removal efficiencies of lead and polonium vary a lot depending on the chemical form in which they occur in water. They can be reliably removed from water by reverse osmosis only. Other treatment methods, such as ion exchange and activated carbon filtration, remove lead and polonium partly. Lead and polonium are removed more efficiently when they are bound onto smaller particles

  3. Removal of radionuclides from household water

    International Nuclear Information System (INIS)

    Vesterbacka, P.; Turtiainen, T.; Haemaelaeinen, K.; Salonen, L.; Arvela, H.

    2007-02-01

    Research upon methods for removing radionuclides from household water was initiated in Finland in 1995. Three research projects, of which two were carried out with National Technology Agency of Finland and one with CEC, have been completed by the end of 2002. One of the main objectives of the research was to compose a guidebook for consumers and water treatment companies. Radon can be removed from household water by aeration and by activated carbon filtration. Aerators that are well designed and set up can remove over 90% of waterborne radon. The best aerators have achieved removal efficiencies that are nearly 100%. However, setting up an aeration system requires thorough planning. Also, activated carbon filtration removes radon efficiently. The removal efficiencies have been over 90%, often nearly 100%. Depending on the water quality and usage, the carbon batch inside the filter needs to be changed every 2 - 3 years. Since activated carbon filters emit gamma radiation while in use, they should not be installed inside the dwelling but in a separate building or by the well. It is recommended that uranium be removed from drinking water by anion exchange, which is the most efficient removal method for this purpose. Typically, the removal efficiencies are nearly 100%. The one exception is the so called tap filter, the removal efficiency of which depends on uranium concentration in raw water and the rate of water flow. High saline concentration in water may extricate uranium from ion exchange resin. Changes in plumbing pressure or pH-value do not have any significant influence in uranium retention. Removal efficiencies of lead and polonium vary a lot depending on the chemical form in which they occur in water. They can be reliably removed from water by reverse osmosis only. Other treatment methods, such as ion exchange and activated carbon filtration, remove lead and polonium partly. Lead and polonium are removed more efficiently when they are bound onto smaller

  4. Near real-time estimation of water vapour in the troposphere using ground GNSS and the meteorological data

    Directory of Open Access Journals (Sweden)

    J. Bosy

    2012-09-01

    Full Text Available The near real-time (NRT high resolution water vapour distribution models can be constructed based on GNSS observations delivered from Ground Base Augmentation Systems (GBAS and ground meteorological data. Since 2008 in the territory of Poland, a GBAS system called ASG-EUPOS (Active Geodetic Network has been operating. This paper addresses the problems concerning construction of the NRT model of water vapour distribution in the troposphere near Poland. The first section presents all available GNSS and ground meteorological stations in the area of Poland and neighbouring countries. In this section, data feeding scheme is discussed, together with timeline and time resolution. The high consistency between measured and interpolated temperature value is shown, whereas some discrepancy in the pressure is observed. In the second section, the NRT GNSS data processing strategy of ASG-EUPOS network is discussed. Preliminary results show fine alignment of the obtained Zenith Troposphere Delays (ZTDs with reference data from European Permanent Network (EPN processing center. The validation of NRT troposphere products against daily solution shows 15 mm standard deviation of obtained ZTD differences. The last section presents the first results of 2-D water vapour distribution above the GNSS network and application of the tomographic model to 3-D distribution of water vapour in the atmosphere. The GNSS tomography model, working on the simulated data from numerical forecast model, shows high consistency with the reference data (by means of standard deviation 4 mm km−1 or 4 ppm, however, noise analysis shows high solution sensitivity to errors in observations. The discrepancy for real data preliminary solution (measured as a mean standard deviation between reference NWP data and tomography data was on the level of 9 mm km−1 (or 9 ppm in terms of wet refractivity.

  5. Nitrate Removal from Ground Water: A Review

    Directory of Open Access Journals (Sweden)

    Archna

    2012-01-01

    Full Text Available Nitrate contamination of ground water resources has increased in Asia, Europe, United States, and various other parts of the world. This trend has raised concern as nitrates cause methemoglobinemia and cancer. Several treatment processes can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that biological denitrification is more acceptable for nitrate removal than reverse osmosis and ion exchange. This paper reviews the developments in the field of nitrate removal processes which can be effectively used for denitrifying ground water as well as industrial water.

  6. Long-term series of tropospheric water vapour amounts and HDO/H2O ratio profiles above Jungfraujoch.

    Science.gov (United States)

    Lejeune, B.; Mahieu, E.; Schneider, M.; Hase, F.; Servais, C.; Demoulin, P.

    2012-04-01

    Water vapour is a crucial climate variable involved in many processes which widely determine the energy budget of our planet. In particular, water vapour is the dominant greenhouse gas in the Earth's atmosphere and its radiative forcing is maximum in the middle and upper troposphere. Because of the extremely high variability of water vapour concentration in time and space, it is challenging for the available relevant measurement techniques to provide a consistent data set useful for trend analyses and climate studies. Schneider et al. (2006a) showed that ground-based Fourier Transform Infrared (FTIR) spectroscopy, performed from mountain observatories, allows for the detection of H2O variabilities up to the tropopause. Furthermore, the FTIR measurements allow the retrieval of HDO amounts and therefore the monitoring of HDO/H2O ratio profiles whose variations act as markers for the source and history of the atmospheric water vapour. In the framework of the MUSICA European project (Multi-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water, http://www.imk-asf.kit.edu/english/musica.php), a new approach has been developed and optimized by M. Schneider and F. Hase, using the PROFFIT algorithm, to consistently retrieve tropospheric water vapour profiles from high-resolution ground-based infrared solar spectra and so taking benefit from available long-term data sets of ground-based observations. The retrieval of the water isotopologues is performed on a logarithmic scale from 14 micro-windows located in the 2600-3100 cm-1 region. Other important features of this new retrieval strategy are: a speed dependant Voigt line shape model, a joint temperature profile retrieval and an interspecies constraint for the HDO/H2O profiles. In this contribution, we will combine the quality of the MUSICA strategy and of our observations, which are recorded on a regular basis with FTIR spectrometers, under clear-sky conditions, at the NDACC site

  7. Vapour dynamics during magma-water interaction experiments: hydromagmatic origins of submarine volcaniclastic particles (limu o Pele)

    Science.gov (United States)

    Schipper, C. Ian; Sonder, Ingo; Schmid, Andrea; White, James D. L.; Dürig, Tobias; Zimanowski, Bernd; Büttner, Ralf

    2013-03-01

    Recent observations have shattered the long-held theory that deep-sea (>500 m) explosive eruptions are impossible; however, determining the dynamics of unobserved eruptions requires interpretation of the deposits they produce. For accurate interpretation to be possible, the relative abilities of explosive magmatic degassing and non-explosive magma-water interaction to produce characteristic submarine volcaniclastic particles such as `limu o Pele' (bubble wall shards of glass) must be established. We experimentally address this problem by pouring remelted basalt (1300 °C, anhydrous) into a transparent, water-filled reservoir, recording the interaction with a high-speed video camera and applying existing heat transfer models. We performed the experiments under moderate to high degrees of water subcooling (˜8 l of water at 58 and 3 °C), with ˜0.1 to 0.15 kg of melt poured at ˜10-2 kg s-1. Videos show the non-explosive, hydromagmatic blowing and bursting of isolated melt bubbles to form limu o Pele particles that are indistinguishable from those found in submarine volcaniclastic deposits. Pool boiling around growing melt bubbles progresses from metastable vapour film insulation, through vapour film retraction/collapse, to direct melt-water contact. These stages are linked to the evolution of melt-water heat transfer to verify the inverse relationship between vapour film stability and the degree of water subcooling. The direct contact stage in particular explains the extremely rapid quench rates determined from glass relaxation speedometry for natural limu. Since our experimentally produced limu is made entirely by the entrapping of ambient water in degassed basaltic melt, we argue that the presence of fast-quenched limu o Pele in natural deposits is not diagnostic of volatile-driven explosive eruptions. This must be taken into account if submarine eruption dynamics are to be accurately inferred from the deposits and particles they produce.

  8. Precipitable water vapour forecasting: a tool for optimizing IR observations at Roque de los Muchachos Observatory.

    Science.gov (United States)

    Pérez-Jordán, G.; Castro-Almazán, J. A.; Muñoz-Tuñón, C.

    2018-04-01

    We validate the Weather Research and Forecasting (WRF) model for precipitable water vapour (PWV) forecasting as a fully operational tool for optimizing astronomical infrared (IR) observations at Roque de los Muchachos Observatory (ORM). For the model validation we used GNSS-based (Global Navigation Satellite System) data from the PWV monitor located at the ORM. We have run WRF every 24 h for near two months, with a horizon of 48 hours (hourly forecasts), from 2016 January 11 to 2016 March 4. These runs represent 1296 hourly forecast points. The validation is carried out using different approaches: performance as a function of the forecast range, time horizon accuracy, performance as a function of the PWV value, and performance of the operational WRF time series with 24- and 48-hour horizons. Excellent agreement was found between the model forecasts and observations, with R =0.951 and R =0.904 for the 24- and 48-h forecast time series respectively. The 48-h forecast was further improved by correcting a time lag of 2 h found in the predictions. The final errors, taking into account all the uncertainties involved, are 1.75 mm for the 24-h forecasts and 1.99 mm for 48 h. We found linear trends in both the correlation and RMSE of the residuals (measurements - forecasts) as a function of the forecast range within the horizons analysed (up to 48 h). In summary, the WRF performance is excellent and accurate, thus allowing it to be implemented as an operational tool at the ORM.

  9. Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2009-04-01

    We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements), the other in central Israel (29 measurements). The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences (RMSD) were 1.8 g/m3 and 3.4 g/m3 for

  10. Novel method for water vapour monitoring using wireless communication networks measurements

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2010-09-01

    We propose a new technique for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from microwave links used in a backhaul cellular network that show very good correlation with surface station humidity measurements (comparisons were performed for several links, found at different locations, during different time periods, showing correlations in the range of 0.5-0.9).

  11. Heat and water mass transfer in unsaturated swelling clay based buffer: discussion on the effect of the thermal gradient and on the diffusion of water vapour

    Energy Technology Data Exchange (ETDEWEB)

    Robinet, J.O. [Euro-Geomat-Consulting (France)]|[Institut National des Sciences Appliquees (INSA), 35 - Rennes (France); Plas, F. [Agence Nationale pour la Gestion des Dechets Radioactifs (ANDRA), 92 - Chatenay Malabry (France)

    2005-07-01

    The modelling of heat, mass transfer and the behaviour coupled thermo-hydro-mechanical in swelling clay require the development of appropriate constitutive laws as well as experimental data. This former approach, allows the quantitative validation of the theoretical models. In general modelling approaches consider dominant mechanisms, (i) Fourier law for diffusion of heat, (ii) generalized Darcy law for convection of liquid water, (iii) Flick law for diffusion of water vapour, and elastic-plastic models wit h hydric hardening and thermal damage/expansion for strain-stress behaviour. Transfer of dry air and water under thermal gradient and capillary (e.g. suction) gradient in unsaturated compacted swelling clays consider evaporation, migration and condensation. These transfers take into account the capillary effect. This effect is an evaporation of liquid water in the hot part for temperature higher than 100 C associated with a, diffusion of water vapor towards cold part then condensation, and convection of liquid water with gradient of suction in the opposite direction of the water vapour diffusion. High values of the diffusion coefficient of the vapour water are considered about 10{sup -7}m{sup 2}/s. Some thermal experiments related (i) low values of the water vapour diffusion coefficient in compacted swelling clays, 2004) and (ii) a significant drying associated with a water transfer even for temperature lower than 100 C. Other enhancement phenomena are used to explain these data and observations: the vaporization is a continuous process. At short term the mechanism of drying at short term is the thermal effect on the capillary pressure (e.g. surface tension depending of temperature); the thermal gradient is a driving force. When a temperature gradient is applied, diffusion occurs in order to reach equilibrium, e.g. to make the chemical potential (m) of each component uniform throughout. This mechanism is called thermal diffusion. This paper proposes a discussion

  12. Response of water vapour D-excess to land–atmosphere interactions in a semi-arid environment

    KAUST Repository

    Parkes, Stephen; McCabe, Matthew; Griffiths, Alan D.; Wang, Lixin; Chambers, Scott; Ershadi, Ali; Williams, Alastair G.; Strauss, Josiah; Element, Adrian

    2017-01-01

    The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour (d =δH-8× δO) can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (d). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (d) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime d values. The low d observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime d and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime d variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of d values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate d can generally be expected to show large spatial and temporal variability and to depend on the soil moisture state. For long periods between rain events, common in semi-arid environments, ET would be expected to impose negative forcing on the surface d. Spatial and temporal variability of D-excess in ET fluxes therefore needs to be considered when using d to study

  13. Response of water vapour D-excess to land–atmosphere interactions in a semi-arid environment

    KAUST Repository

    Parkes, Stephen

    2017-01-27

    The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour (d =δH-8× δO) can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (d). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (d) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime d values. The low d observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime d and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime d variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of d values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate d can generally be expected to show large spatial and temporal variability and to depend on the soil moisture state. For long periods between rain events, common in semi-arid environments, ET would be expected to impose negative forcing on the surface d. Spatial and temporal variability of D-excess in ET fluxes therefore needs to be considered when using d to study

  14. Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere

    Directory of Open Access Journals (Sweden)

    V. Barabash

    2014-03-01

    Full Text Available Mesospheric water vapour concentration effects on the ion composition and electron density in the lower ionosphere under quiet geophysical conditions were examined. Water vapour is an important compound in the mesosphere and the lower thermosphere that affects ion composition due to hydrogen radical production and consequently modifies the electron number density. Recent lower-ionosphere investigations have primarily concentrated on the geomagnetic disturbance periods. Meanwhile, studies on the electron density under quiet conditions are quite rare. The goal of this study is to contribute to a better understanding of the ionospheric parameter responses to water vapour variability in the quiet lower ionosphere. By applying a numerical D region ion chemistry model, we evaluated efficiencies for the channels forming hydrated cluster ions from the NO+ and O2+ primary ions (i.e. NO+.H2O and O2+.H2O, respectively, and the channel forming H+(H2On proton hydrates from water clusters at different altitudes using profiles with low and high water vapour concentrations. Profiles for positive ions, effective recombination coefficients and electrons were modelled for three particular cases using electron density measurements obtained during rocket campaigns. It was found that the water vapour concentration variations in the mesosphere affect the position of both the Cl2+ proton hydrate layer upper border, comprising the NO+(H2On and O2+(H2On hydrated cluster ions, and the Cl1+ hydrate cluster layer lower border, comprising the H+(H2On pure proton hydrates, as well as the numerical cluster densities. The water variations caused large changes in the effective recombination coefficient and electron density between altitudes of 75 and 87 km. However, the effective recombination coefficient, αeff, and electron number density did not respond even to large water vapour concentration variations occurring at other altitudes in the mesosphere. We determined the water

  15. Partitioning understory evapotranspiration in semi-arid ecosystems in Namibia using the isotopic composition of water vapour

    Science.gov (United States)

    de Blécourt, Marleen; Gaj, Marcel; Holtorf, Kim-Kirsten; Gröngröft, Alexander; Brokate, Ralph; Himmelsbach, Thomas; Eschenbach, Annette

    2016-04-01

    In dry environments with a sparse vegetation cover, understory evapotranspiration is a major component of the ecosystem water balance. Consequently, knowledge on the size of evapotranspiration fluxes and the driving factors is important for our understanding of the hydrological cycle. Understory evapotranspiration is made up of soil evaporation and plant transpiration. Soil evaporation can be measured directly from patches free of vegetation. However, when understory vegetation is present distinguishing between soil evaporation and plant transpiration is challenging. In this study, we aim to partition understory evapotranspiration based on an approach that combines the measurements of water-vapour fluxes using the closed chamber method with measurements of the isotopic composition of water vapour. The measurements were done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management). The study sites were located in three different semi-arid ecosystems in Namibia: thornbush savanna, Baikiaea woodland and shrubland. At each site measurements were done under tree canopies as well as at unshaded areas between the canopies. We measured evaporation from the bare soil and evapotranspiration from patches covered with herbaceous species and shrubs using a transparent chamber connected with an infrared gas analyser (LI-8100A, LICOR Inc.). The stable isotope composition of water vapour inside the chamber and depth profiles of soil water stable isotopes were determined in-situ using a tuneable off-axis integrated cavity output spectroscope (OA-ICOS, Los Gatos Research, DLT 100). Xylem samples were extracted using the cryogenic vacuum extraction method and the isotopic composition of the extracted water was measured subsequently with a cavity-ring-down spectrometer (CRDS L2120-i, Picarro Inc.). We will present the quantified fluxes of understory evapotranspiration measured in the three different ecosystems, show the

  16. Iron and manganese removal from drinking water

    OpenAIRE

    Pascu, Daniela-Elena; Neagu (Pascu), Mihaela; Alina Traistaru, Gina; Nechifor, Aurelia Cristina; Raluca Miron, Alexandra

    2016-01-01

    The purpose of the present study is to find a suitable method for removal of iron and manganese from ground water, considering both local economical and environmental aspects. Ground water is a highly important source of drinking water in Romania. Ground water is naturally pure from bacteria at a 25 m depth or more. However, solved metals may occur and if the levels are too high, the water is not drinkable. Different processes, such as electrochemical and combined electrochemical-adsorption m...

  17. Norm removal from frac water

    Science.gov (United States)

    Silva, James Manio; Matis, Hope; Kostedt, IV, William Leonard

    2014-11-18

    A method for treating low barium frac water includes contacting a frac water stream with a radium selective complexing resin to produce a low radium stream, passing the low radium stream through a thermal brine concentrator to produce a concentrated brine; and passing the concentrated brine through a thermal crystallizer to yield road salt.

  18. Removal of oil from water by bentonite

    International Nuclear Information System (INIS)

    Moazed, H.; Viraraghavan, T.

    1999-01-01

    Many materials, included activated carbon, peat, coal, fiberglass, polypropylene, organoclay and bentonite have been used for removing oils and grease from water. However, bentonite has been used only rarely for this purpose. In this study Na-bentonite was used to remove oil from oil-in-water emulsions of various kinds such as standard mineral oil, cutting oils, refinery effluent and produced water from production wells at Estevan, Saskatchewan. Removal efficiencies obtained were 85 to 96 per cent for cutting oils, 84 to 86 per cent for produced water and 54 to 87 per cent for refinery effluent. Bentonite proved to be more effective in the removal of oil from oil-in-water emulsions than from actual waste waters; up to 96 percent from oil-in-water emulsions to only 87 per cent from actual waste water. The percentage of oil removed was found to be a function of the amount of bentonite added and the adsorption time up to the equilibrium time. Result also showed that the Langmuir, Freundlich and BET isotherms are well suited to describe the adsorption of oil by bentonite from the various oily waters employed in this study. 15 refs

  19. N-Basin water removal plan

    International Nuclear Information System (INIS)

    Nellesen, A.L.

    1997-07-01

    This ALARA review provides a description of the engineering and administrative controls used to manage personnel exposure, control contamination levels, and airborne radioactivity concentrations, while removing water and stabilizing surfaces in the 105-N Fuel Storage Building

  20. Nitrate Removal from Ground Water: A Review

    OpenAIRE

    Archna; Sharma, Surinder K.; Sobti, Ranbir Chander

    2012-01-01

    Nitrate contamination of ground water resources has increased in Asia, Europe, United States, and various other parts of the world. This trend has raised concern as nitrates cause methemoglobinemia and cancer. Several treatment processes can remove nitrates from water with varying degrees of efficiency, cost, and ease of operation. Available technical data, experience, and economics indicate that biological denitrification is more acceptable for nitrate removal than reverse osmosis and ion ex...

  1. Arsenic removal for ceramic water filters

    Directory of Open Access Journals (Sweden)

    Mishant Kumar

    2013-02-01

    Full Text Available Arsenic in drinking water is a hazard to human health and is a known carcinogen (Mass 1992. Resource Development International – Cambodia (RDIC has researched, developed, and manufactured simple ceramic water fi lters (CWF which have proved to be extremely effective in removing pathogens from water. These fi lters however, do not remove arsenic from water, which exists in the source water at levels above the World Health Organisation (WHO guideline of 10μg/L. The aims of this literature based study were to investigate conventional and non-conventional arsenic removal processes, and to discuss the options for applying an arsenic removal technology to the CWFs produced by RDIC. It was found that conventional arsenic removal technologies are diffi cult to implement in the context of household water treatment in a developing country. This study suggested that non-conventional arsenic removal technologies shall be more effective and that field studies must be undertaken to verify the success of such methods.

  2. Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

    Directory of Open Access Journals (Sweden)

    N. David

    2009-04-01

    Full Text Available We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks.

    Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition – many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both may also interfere with the ability to conduct accurate measurements.

    We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements, the other in central Israel (29 measurements. The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences

  3. Assessment of small-scale integrated water vapour variability during HOPE

    Science.gov (United States)

    Steinke, S.; Eikenberg, S.; Löhnert, U.; Dick, G.; Klocke, D.; Di Girolamo, P.; Crewell, S.

    2015-03-01

    The spatio-temporal variability of integrated water vapour (IWV) on small scales of less than 10 km and hours is assessed with data from the 2 months of the High Definition Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observational Prototype Experiment (HOPE). The statistical intercomparison of the unique set of observations during HOPE (microwave radiometer (MWR), Global Positioning System (GPS), sun photometer, radiosondes, Raman lidar, infrared and near-infrared Moderate Resolution Imaging Spectroradiometer (MODIS) on the satellites Aqua and Terra) measuring close together reveals a good agreement in terms of random differences (standard deviation ≤1 kg m-2) and correlation coefficient (≥ 0.98). The exception is MODIS, which appears to suffer from insufficient cloud filtering. For a case study during HOPE featuring a typical boundary layer development, the IWV variability in time and space on scales of less than 10 km and less than 1 h is investigated in detail. For this purpose, the measurements are complemented by simulations with the novel ICOsahedral Nonhydrostatic modelling framework (ICON), which for this study has a horizontal resolution of 156 m. These runs show that differences in space of 3-4 km or time of 10-15 min induce IWV variabilities on the order of 0.4 kg m-2. This model finding is confirmed by observed time series from two MWRs approximately 3 km apart with a comparable temporal resolution of a few seconds. Standard deviations of IWV derived from MWR measurements reveal a high variability (> 1 kg m-2) even at very short time scales of a few minutes. These cannot be captured by the temporally lower-resolved instruments and by operational numerical weather prediction models such as COSMO-DE (an application of the Consortium for Small-scale Modelling covering Germany) of Deutscher Wetterdienst, which is included in the comparison. However, for time scales larger than 1 h, a sampling resolution of 15 min is

  4. Evaluation of balloon and satellite water vapour measurements in the Southern tropical and subtropical UTLS during the HIBISCUS campaign

    Science.gov (United States)

    Montoux, N.; Hauchecorne, A.; Pommereau, J.-P.; Lefèvre, F.; Durry, G.; Jones, R. L.; Rozanov, A.; Dhomse, S.; Burrows, J. P.; Morel, B.; Bencherif, H.

    2009-07-01

    Balloon water vapour in situ and remote measurements in the tropical upper troposphere and lower stratosphere (UTLS) obtained during the HIBISCUS campaign around 20° S in Brazil in February-March 2004 using a tunable diode laser (μSDLA), a surface acoustic wave (SAW) and a Vis-NIR solar occultation spectrometer (SAOZ) on a long duration balloon, have been used for evaluating the performances of satellite borne remote water vapour instruments available at the same latitude and measurement period. In the stratosphere, HALOE displays the best precision (2.5%), followed by SAGE II (7%), MIPAS (10%), SAOZ (20-25%) and SCIAMACHY (35%), all of which show approximately constant H2O mixing ratios between 20-25 km. Compared to HALOE of ±10% accuracy between 0.1-100 hPa, SAGE II and SAOZ show insignificant biases, MIPAS is wetter by 10% and SCIAMACHY dryer by 20%. The currently available GOMOS profiles of 25% precision show a positive vertical gradient in error for identified reasons. Compared to these, the water vapour of the Reprobus Chemistry Transport Model, forced at pressures higher than 95 hPa by the ECMWF analyses, is dryer by about 1 ppmv (20%). In the lower stratosphere between 16-20 km, most notable features are the steep degradation of MIPAS precision below 18 km, and the appearance of biases between instruments far larger than their quoted total uncertainty. HALOE and SAGE II (after spectral adjustment for reducing the bias with HALOE at northern mid-latitudes) both show decreases of water vapour with a minimum at the tropopause not seen by other instruments or the model, possibly attributable to an increasing error in the HALOE altitude registration. Between 16-18 km where the water vapour concentration shows little horizontal variability, and where the μSDLA balloon measurements are not perturbed by outgassing, the average mixing ratios reported by the remote sensing instruments are substantially lower than the 4-5 ppmv observed by the μSDLA. Differences

  5. Boron removal from geothermal waters by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey); Yilmaz, M. Tolga; Paluluoglu, Cihan [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)

    2008-05-01

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm{sup 2}, but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.

  6. Boron removal from geothermal waters by electrocoagulation

    International Nuclear Information System (INIS)

    Yilmaz, A. Erdem; Boncukcuoglu, Recep; Kocakerim, M. Muhtar; Yilmaz, M. Tolga; Paluluoglu, Cihan

    2008-01-01

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm 2 , but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%

  7. Automated calibration of laser spectrometer measurements of δ18 O and δ2 H values in water vapour using a Dew Point Generator.

    Science.gov (United States)

    Munksgaard, Niels C; Cheesman, Alexander W; Gray-Spence, Andrew; Cernusak, Lucas A; Bird, Michael I

    2018-06-30

    Continuous measurement of stable O and H isotope compositions in water vapour requires automated calibration for remote field deployments. We developed a new low-cost device for calibration of both water vapour mole fraction and isotope composition. We coupled a commercially available dew point generator (DPG) to a laser spectrometer and developed hardware for water and air handling along with software for automated operation and data processing. We characterised isotopic fractionation in the DPG, conducted a field test and assessed the influence of critical parameters on the performance of the device. An analysis time of 1 hour was sufficient to achieve memory-free analysis of two water vapour standards and the δ 18 O and δ 2 H values were found to be independent of water vapour concentration over a range of ≈20,000-33,000 ppm. The reproducibility of the standard vapours over a 10-day period was better than 0.14 ‰ and 0.75 ‰ for δ 18 O and δ 2 H values, respectively (1 σ, n = 11) prior to drift correction and calibration. The analytical accuracy was confirmed by the analysis of a third independent vapour standard. The DPG distillation process requires that isotope calibration takes account of DPG temperature, analysis time, injected water volume and air flow rate. The automated calibration system provides high accuracy and precision and is a robust, cost-effective option for long-term field measurements of water vapour isotopes. The necessary modifications to the DPG are minor and easily reversible. Copyright © 2018 John Wiley & Sons, Ltd.

  8. Action of the chlorine trifluoride on water vapour. Analysis of reaction products. Technical report - 589

    International Nuclear Information System (INIS)

    Bougon, R.

    1961-06-01

    As the separation of uranium 235 from uranium 238 by gaseous diffusion under the form of uranium hexa-fluoride requires the use of materials which may contain some impurities retained by chemical or physical bounds, this report addresses the use of a reactant which would allow these impurities to be removed. Due to its properties (inert with respect to UF 6 ; transforms most of impurities into volatile compounds, and different UF compounds into UF 6 ; strongly reacts on water; all its degradation products are volatile), chlorine trifluoride (ClF 3 ) has been chosen. It is used for the preprocessing of materials for their passivation with respect to UF 6 , and for a post-processing for the regeneration of porous materials by transformation of UF 4 , UO 2 F 2 and UF x into UF 6 . The authors more particularly studied the reaction between ClF 3 and water

  9. The water vapour continuum in near-infrared windows - Current understanding and prospects for its inclusion in spectroscopic databases

    Science.gov (United States)

    Shine, Keith P.; Campargue, Alain; Mondelain, Didier; McPheat, Robert A.; Ptashnik, Igor V.; Weidmann, Damien

    2016-09-01

    Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth's atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm-1) and include reference to the window centred on 2600 cm-1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback - cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum - as an example, we

  10. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Water vapour

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2003-12-01

    Bibliographies of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for water vapour (H 2 O, D 2 O and HDO). About 1200 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1915 through 2000 for H 2 O. Finally, author's comments for electron collision cross sections and photodissociation processes of H 2 O are given. (author)

  11. The role of water-vapour photodissociation on the formation of a deep minimum in mesopause ozone

    Directory of Open Access Journals (Sweden)

    I. M. Vardavas

    1998-02-01

    Full Text Available A one-dimensional atmospheric photochemical model with an altitude grid of about 1.5 km was used to examine the structure of the global mean vertical ozone profile and its night-time-to-daytime variation in the upper atmosphere. Two distinct ozone layers are predicted, separated by a sharp drop in the ozone concentration near the mesopause. This naturally occurring mesopause ozone deep minimum is primarily produced by the rapid increase in the destruction of water vapour, and hence increase in HOx, at altitudes between 80 and 85 km, a region where water-vapour photodissociation by ultraviolet radiation of the solar Lyman-alpha line is significant, and where the supply of water vapour is maintained by methane oxidation even for very dry conditions at the tropospheric-stratospheric exchange region. The model indicates that the depth of the mesopause ozone minimum is limited by the efficiency with which inactive molecular hydrogen is produced, either by the conversion of atomic hydrogen to molecular hydrogen via one of the reaction channels of H with HO2, or by Lyman-alpha photodissociation of water vapour via the channel that leads to the production of molecular hydrogen. The ozone concentration rapidly recovers above 85 km due to the rapid increase in O produced by the photodissociation of O2 by absorption of ultraviolet solar radiation in the Schumann-Runge bands and continuum. Above 90 km, there is a decrease in ozone due to photolysis as the production of ozone through the three-body recombination of O2 and O becomes slower with decreasing pressure. The model also predicts two peaks in the night-time/daytime ozone ratio, one near 75 km and the other near 110 km, plus a strong peak in the night-time/daytime ratio of OH near 110 km. Recent observational evidence supports the predictions of the model.Key words. Atmospheric composition and structure · Middle atmosphere · Thermosphere · Transmission and scattering of radiation

  12. Radium removal from Australian spa waters

    International Nuclear Information System (INIS)

    Dickson, B.L.; Meakins, R.L.; Bland, C.J.

    1982-01-01

    The dissolved radium content of some mineral spring waters in Victoria and Queensland has been found to exceed the maximum permissible concentration in drinking water. Activities in excess of 40 pCi/1 were measured in some bottles. Studies revealed that the dissolved radium content decreased markedly if the spring water was aerated and filtered prior to bottling. The sediment removed contained ferric hydroxide which is a natural scavenging agent for radium. The formation of such sediments in storage tanks and their removal prior to bottling may create a possible radiation hazard

  13. Uranium speciation and removal from well water

    International Nuclear Information System (INIS)

    Ayaz, B.; DeVol, T.; Navratil, J.D.

    2001-01-01

    The purpose of this work was to determine the form of uranium present in the well water and to test the effectiveness of common household treatment devices to remove uranium and radium. Batch tests with activated carbon, iron powder, anion exchange resin and cation exchange resin were used to characterize the form of uranium in the drinking water. In the tests, water and the separation materials were first equilibrated, filtered and then analyzed by alpha spectrometry. The results of the batch tests showed that it is possible to remove greater than 90% of the uranium and radium in the drinking water by using any of the sorbents listed above. Simple filtration with 0.1 μm had little to no impact on uranium removal. Results of tests using household treatment devices will also be presented. (authors)

  14. Applicability of the Guggenheim–Anderson–Boer water vapour sorption model for estimation of soil specific surface area

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Møldrup, Per

    2018-01-01

    Soil specific surface area (SA) controls fundamental soil processes such as retention of water, ion exchange, and adsorption and release of plant nutrients and contaminants. Conventional methods for determining SA include adsorption of polar or non‐polar fluid molecules with associated advantages...... parameters varied depending on the water activity or relative humidity range of measured data (0.03–0.93 compared with 0.10–0.80), whereas the variation for desorption was minimal. For desorption isotherms, the average water activity value at which the GAB monolayer parameter was obtained was 0......‐based modelling approaches to determine SA. Measured water vapour adsorption and desorption isotherms for 321 soil samples were used to parameterize the GAB model, the Brunauer–Emmet–Teller (BET) equation and a film adsorption Tuller–Or (TO) model to estimate SA. For adsorption isotherms, the values of the GAB...

  15. Density and vapour pressure of mixed-solvent desiccant systems (propylene glycol or dipropylene glycol or tripropylene glycol + magnesium chloride + water)

    International Nuclear Information System (INIS)

    Chen, Shang-Yi; Soriano, Allan N.; Leron, Rhoda B.; Li, Meng-Hui

    2014-01-01

    In this present work, new experimental data for density and vapour pressure of the mixed-solvent desiccant systems containing {40 wt% glycol (propylene or dipropylene or tripropylene) + (4 or 9 or 16 wt%) magnesium chloride salt + water} were reported for temperatures up to 343.15 K at normal atmospheric condition. The density and vapour pressure data obtained are presented as a function of temperature and composition. An empirical equation was used to correlate the temperature and compositional dependence of the density values. A model based on the mean spherical approximation for aqueous electrolyte solutions incorporating the pseudo-solvent approach was used to represent the vapour pressure as a function of temperature and composition. Satisfactory results were obtained for both density and vapour pressure calculations

  16. Uranium removal from the water supply

    International Nuclear Information System (INIS)

    Miranzadeh, Mohammad Bagher.

    1996-01-01

    Uranium can be naturally occurring radionuclides that contaminate some potable water supplies. Uranium is found both in surface water and ground water supplies. The United States Environmental Protection Agency recently proposed a maximum contaminant of 20 micro gram/liter for uranium because of concerns about its association with kidney disease and cancer. uranium can be removed from the supply by strong base anion-resin. Exhausted resin is regenerated by sodium chloride solution. (Author)

  17. Effect of temperature and relative humidity on the water vapour permeability and mechanical properties of cassava starch and soy protein concentrate based edible films.

    Science.gov (United States)

    Chinma, C E; Ariahu, C C; Alakali, J S

    2015-04-01

    The effect of temperature and relative humidity on the water vapour permeability (WVP) and mechanical properties of cassava starch and soy protein concentrate (SPC) based edible films containing 20 % glycerol level were studied. Tensile strength and elastic modulus of edible films increased with increase in temperature and decreased with increase in relative humidity, while elongation at break decreased. Water vapour permeability of the films increased (2.6-4.3 g.mm/m(2).day.kPa) with increase in temperature and relative humidity. The temperature dependence of water vapour permeation of cassava starch-soy protein concentrate films followed Arrhenius relationship. Activation energy (Ea) of water vapour permeation of cassava starch-soy protein concentrate edible films ranged from 1.9 to 5.3 kJ/mol (R (2)  ≥ 0.93) and increased with increase in SPC addition. The Ea values were lower for the bio-films than for polyvinylidene chloride, polypropylene and polyethylene which are an indication of low water vapour permeability of the developed biofilms compared to those synthetic films.

  18. REMOVAL OF HEXAVALENT CHROMIUM FROM DRINKING WATER

    Directory of Open Access Journals (Sweden)

    A. R. Asgari ، F. Vaezi ، S. Nasseri ، O. Dördelmann ، A. H. Mahvi ، E. Dehghani Fard

    2008-10-01

    Full Text Available Removal of chromium can be accomplished by various methods but none of them is cost-effective in meeting drinking water standards. For this study, granular ferric hydroxide was used as adsorbent for removal of hexavalent chromium. Besides, the effects of changing contact time, pH and concentrations of competitive anions were determined for different amounts of granular ferric hydroxide. It was found that granular ferric hydroxide has a high capacity for adsorption of hexavalent chromium from water at pH≤7 and in 90 min contact time. Maximum adsorption capacity was determined to be 0.788 mg Cr+6/g granular ferric hydroxide. Although relatively good adsorption of sulfate and chloride had been specified in this study, the interfering effects of these two anions had not been detected in concentrations of 200 and 400 mg/L. The absorbability of hexavalent chromium by granular ferric hydroxide could be expressed by Freundlich isotherm with R2>0.968. However, the disadvantage was that the iron concentration in water was increased by the granular ferric hydroxide. Nevertheless, granular ferric hydroxide is a promising adsorbent for chromium removal, even in the presence of other interfering compounds, because granular ferric hydroxide treatment can easily be accomplished and removal of excess iron is a simple practice for conventional water treatment plants. Thus, this method could be regarded as a safe and convenient solution to the problem of chromium-polluted water resources.

  19. Iron and manganese removal from drinking water

    Directory of Open Access Journals (Sweden)

    Daniela-Elena Pascu

    2016-04-01

    Full Text Available The purpose of the present study is to find a suitable method for removal of iron and manganese from ground water, considering bothlocal economical and environmental aspects. Ground water is a highly important source of drinking water in Romania. Ground water is naturally pure from bacteria at a 25 m depth or more. However, solved metals may occur and if the levels are too high, the water is not drinkable. Different processes, such as electrochemical and combined electrochemical-adsorption methods have been applied to determine metals content in accordance to reports of National Water Agency from Romania (ANAR. Every water source contains dissolved or particulate compounds. The concentrations of these compounds can affect health, productivity, compliance requirements, or serviceability and cannot be economically removed by conventional filtration means. In this study, we made a comparison between the electrochemical and adsorption methods (using membranes. Both methods have been used to evaluate the efficiency of iron and manganese removal at various times and temperatures. We used two membrane types: composite and cellulose, respectively. Different approaches, including lowering the initial current density and increasing the initial pH were applied. Reaction kinetics was achieved using mathematical models: Jura and Temkin.

  20. Removal of radium from drinking water

    International Nuclear Information System (INIS)

    Clifford, D.A.

    1990-01-01

    The traditional, proven process for radium removal are sodium ion exchange softening, lime softening, and reverse osmosis. The newer, radium-specific column processes include adsorption onto the Dow RSC and BaSO 4 -impregnated alumina. The most promising new radium-specific treatment process for large-scale use is adsorption onto preformed manganese dioxide followed by multimedia or diatomaceous earth filtration The disposal of radium-contaminated wastewaters and sludges from processes under consideration will be a major factor in process selection. The processes of choice for municipal water supply treatment to remove radium are sodium ion exchange softening, lime softening, manganese dioxide adsorption-filtration, and selective adsorption onto the Dow RSC or BaSO 4 -impregnated alumina. Where the water is brackish, reverse osmosis hyperfiltration should also be considered. The radium removal process of choice for whole-house or point-of-entry treatment is sodium ion exchange softening. For point-of-use radium removal, a standard reverse osmosis system including cartridge filtration, activated carbon adsorption, and reverse osmosis hyperfiltration is recommended. Although no cost estimates have been made, the relative costs from most expensive to least expansive, for radium removal in small community water supplies are reverse osmosis, sodium ion exchange softening, lime soda softening, manganese dioxide adsorption-filtration, and the radium-selective adsorbents. 34 refs., 7 figs., 2 tabs

  1. Trends and variability of midlatitude stratospheric water vapour deduced from the re-evaluated Boulder balloon series and HALOE

    Directory of Open Access Journals (Sweden)

    M. Scherer

    2008-03-01

    Full Text Available This paper presents an updated trend analysis of water vapour in the lower midlatitude stratosphere from the Boulder balloon-borne NOAA frostpoint hygrometer measurements and from the Halogen Occulation Experiment (HALOE. Two corrections for instrumental bias are applied to homogenise the frostpoint data series, and a quality assessment of all soundings after 1991 is presented. Linear trend estimates based on the corrected data for the period 1980–2000 are up to 40% lower than previously reported. Vertically resolved trends and variability are calculated with a multi regression analysis including the quasi-biennal oscillation and equivalent latitude as explanatory variables. In the range of 380 to 640 K potential temperature (≈14 to 25 km, the frostpoint data from 1981 to 2006 show positive linear trends between 0.3±0.3 and 0.7±0.1%/yr. The same dataset shows trends between −0.2±0.3 and 1.0±0.3%/yr for the period 1992 to 2005. HALOE data over the same time period suggest negative trends ranging from −1.1±0.2 to −0.1±0.1%/yr. In the lower stratosphere, a rapid drop of water vapour is observed in 2000/2001 with little change since. At higher altitudes, the transition is more gradual, with slowly decreasing concentrations between 2001 and 2007. This pattern is consistent with a change induced by a drop of water concentrations at entry into the stratosphere. Previously noted differences in trends and variability between frostpoint and HALOE remain for the homogenised data. Due to uncertainties in reanalysis temperatures and stratospheric transport combined with uncertainties in observations, no quantitative inference about changes of water entering the stratosphere in the tropics could be made with the mid latitude measurements analysed here.

  2. Removal of ciprofloxacin from water by birnessite

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei-Teh, E-mail: atwtj@mail.ncku.edu.tw [Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Chang, Po-Hsiang; Wang, Ya-Siang; Tsai, Yolin; Jean, Jiin-Shuh [Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Li, Zhaohui, E-mail: li@uwp.edu [Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Geosciences, University of Wisconsin – Parkside, Kenosha, WI 53144 (United States); Krukowski, Keith [Department of Geosciences, University of Wisconsin – Parkside, Kenosha, WI 53144 (United States)

    2013-04-15

    Highlights: ► Ciprofloxacin removal by birnessite was accompanied by interlayer cation exchange. ► Layer expansion and FTIR data suggested ciprofloxacin intercalation into birnessite. ► Adsorption capacity of ciprofloxacin into birnessite was limited by surface area. ► Birnessite in soil systems may provide host for ciprofloxacin accumulation. -- Abstract: With more pharmaceuticals and personal care products detected in the surface and waste waters, studies on interactions between these contaminants and soils or sediments have attracted great attention. In this study, the removal of ciprofloxacin (CIP), a fluoroquinolone antibiotic, by birnessite, a layered manganese oxide, in aqueous solution was investigated by batch studies supplemented by X-ray diffraction (XRD) and Fourier transform infrared analyses. Stoichiometric release of exchangeable cations accompanying CIP removal from water confirmed cation exchange as the major mechanism for CIP uptake by birnessite. Interlayer expansion after CIP adsorption on birnessite as revealed by XRD analyses indicated that intercalation contributed significantly to CIP uptake in addition to external surface adsorption. Correlation of CIP adsorption to specific surface area and cation exchange capacity suggested that the former was the limiting factor for CIP uptake. At the adsorption maximum, CIP molecules formed a monolayer on the birnessite surfaces. The adsorbed CIP could be partially removed using a cationic surfactant at a low initial concentration and mostly removed by AlCl{sub 3} at a higher initial concentration, which further supported the cation exchange mechanism for CIP removal by birnessite. The results indicated that the presence of layered Mn-oxide in the soil and waste water treatment systems may provide host for CIP accumulation.

  3. Removal of ciprofloxacin from water by birnessite

    International Nuclear Information System (INIS)

    Jiang, Wei-Teh; Chang, Po-Hsiang; Wang, Ya-Siang; Tsai, Yolin; Jean, Jiin-Shuh; Li, Zhaohui; Krukowski, Keith

    2013-01-01

    Highlights: ► Ciprofloxacin removal by birnessite was accompanied by interlayer cation exchange. ► Layer expansion and FTIR data suggested ciprofloxacin intercalation into birnessite. ► Adsorption capacity of ciprofloxacin into birnessite was limited by surface area. ► Birnessite in soil systems may provide host for ciprofloxacin accumulation. -- Abstract: With more pharmaceuticals and personal care products detected in the surface and waste waters, studies on interactions between these contaminants and soils or sediments have attracted great attention. In this study, the removal of ciprofloxacin (CIP), a fluoroquinolone antibiotic, by birnessite, a layered manganese oxide, in aqueous solution was investigated by batch studies supplemented by X-ray diffraction (XRD) and Fourier transform infrared analyses. Stoichiometric release of exchangeable cations accompanying CIP removal from water confirmed cation exchange as the major mechanism for CIP uptake by birnessite. Interlayer expansion after CIP adsorption on birnessite as revealed by XRD analyses indicated that intercalation contributed significantly to CIP uptake in addition to external surface adsorption. Correlation of CIP adsorption to specific surface area and cation exchange capacity suggested that the former was the limiting factor for CIP uptake. At the adsorption maximum, CIP molecules formed a monolayer on the birnessite surfaces. The adsorbed CIP could be partially removed using a cationic surfactant at a low initial concentration and mostly removed by AlCl 3 at a higher initial concentration, which further supported the cation exchange mechanism for CIP removal by birnessite. The results indicated that the presence of layered Mn-oxide in the soil and waste water treatment systems may provide host for CIP accumulation

  4. Isobaric (vapour + liquid + liquid) equilibrium data for (di-n-propyl ether + n-propyl alcohol + water) and (diisopropyl ether + isopropyl alcohol + water) systems at 100 kPa

    International Nuclear Information System (INIS)

    Lladosa, Estela; Monton, Juan B.; Burguet, MaCruz; Torre, Javier de la

    2008-01-01

    Isobaric (vapour + liquid + liquid) equilibria were measured for the (di-n-propyl ether + n-propyl alcohol + water) and (diisopropyl ether + isopropyl alcohol + water) system at 100 kPa. The apparatus used for the determination of (vapour + liquid + liquid) equilibrium data was an all-glass dynamic recirculating still with an ultrasonic homogenizer couple to the boiling flask. The experimental data demonstrated the existence of a heterogeneous ternary azeotrope for both ternary systems. The (vapour + liquid + liquid) equilibria data were found to be thermodynamically consistent for both systems. The experimental data were compared with the estimation using UNIQUAC and NRTL models and the prediction of UNIFAC model

  5. Acceleration induced water removal from ear canals.

    Science.gov (United States)

    Kang, Hosung; Averett, Katelee; Jung, Sunghwan

    2017-11-01

    Children and adults commonly experience having water trapped in the ear canals after swimming. To remove the water, individuals will shake their head sideways. Since a child's ear canal has a smaller diameter, it requires more acceleration of the head to remove the trapped water. In this study, we theoretically and experimentally investigated the acceleration required to break the surface meniscus of the water in artificial ear canals and hydrophobic-coated glass tubes. In experiments, ear canal models were 3D-printed from a CT-scanned human head. Also, glass tubes were coated with silane to match the hydrophobicity in ear canals. Then, using a linear stage, we measured the acceleration values required to forcefully eject the water from the artificial ear canals and glass tubes. A theoretical model was developed to predict the critical acceleration at a given tube diameter and water volume by using a modified Rayleigh-Taylor instability. Furthermore, this research can shed light on the potential of long-term brain injury and damage by shaking the head to push the water out of the ear canal. This research was supported by National Science Foundation Grant CBET-1604424.

  6. Tropospheric water vapour isotopologue data (H216O, H218O, and HD16O) as obtained from NDACC/FTIR solar absorption spectra

    Science.gov (United States)

    Barthlott, Sabine; Schneider, Matthias; Hase, Frank; Blumenstock, Thomas; Kiel, Matthäus; Dubravica, Darko; García, Omaira E.; Sepúlveda, Eliezer; Mengistu Tsidu, Gizaw; Takele Kenea, Samuel; Grutter, Michel; Plaza-Medina, Eddy F.; Stremme, Wolfgang; Strong, Kim; Weaver, Dan; Palm, Mathias; Warneke, Thorsten; Notholt, Justus; Mahieu, Emmanuel; Servais, Christian; Jones, Nicholas; Griffith, David W. T.; Smale, Dan; Robinson, John

    2017-01-01

    We report on the ground-based FTIR (Fourier transform infrared) tropospheric water vapour isotopologue remote sensing data that have been recently made available via the database of NDACC (Network for the Detection of Atmospheric Composition Change; MUSICA/" target="_blank">ftp://ftp.cpc.ncep.noaa.gov/ndacc/MUSICA/) and via doi:10.5281/zenodo.48902. Currently, data are available for 12 globally distributed stations. They have been centrally retrieved and quality-filtered in the framework of the MUSICA project (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). We explain particularities of retrieving the water vapour isotopologue state (vertical distribution of H216O, H218O, and HD16O) and reveal the need for a new metadata template for archiving FTIR isotopologue data. We describe the format of different data components and give recommendations for correct data usage. Data are provided as two data types. The first type is best-suited for tropospheric water vapour distribution studies disregarding different isotopologues (comparison with radiosonde data, analyses of water vapour variability and trends, etc.). The second type is needed for analysing moisture pathways by means of H2O, δD-pair distributions.

  7. Relative humidity effects on water vapour fluxes measured with closed-path eddy-covariance systems with short sampling lines

    DEFF Research Database (Denmark)

    Fratini, Gerardo; Ibrom, Andreas; Arriga, Nicola

    2012-01-01

    It has been formerly recognised that increasing relative humidity in the sampling line of closed-path eddy-covariance systems leads to increasing attenuation of water vapour turbulent fluctuations, resulting in strong latent heat flux losses. This occurrence has been analyzed for very long (50 m...... from eddy-covariance systems featuring short (4 m) and very short (1 m) sampling lines running at the same clover field and show that relative humidity effects persist also for these setups, and should not be neglected. Starting from the work of Ibrom and co-workers, we propose a mixed method...... and correction method proposed here is deemed applicable to closed-path systems featuring a broad range of sampling lines, and indeed applicable also to passive gases as a special case. The methods described in this paper are incorporated, as processing options, in the free and open-source eddy...

  8. New approach for sustaining energetic, efficient and scalable non-equilibrium plasma in water vapours at atmospheric pressure

    International Nuclear Information System (INIS)

    Malik, Muhammad Arif; Schoenbach, Karl H

    2012-01-01

    Energetic and scalable non-equilibrium plasma was formed in pure water vapour at atmospheric pressure between wire-to-strip electrodes on a dielectric surface with one of the electrodes extended forming a conductive plane on the back side of the dielectric surface. The energy deposition increased by an order of magnitude compared with the conventional pulsed corona discharges under the same conditions. The scalability was demonstrated by operating two electrode assemblies with a common conductive plane between two dielectric layers. The energy yields for hydrogen and hydrogen peroxide generation were measured as ∼1.2 g H 2 /kWh and ∼4 g H 2 O 2 /kWh. (fast track communication)

  9. Method of arsenic removal from water

    Science.gov (United States)

    Gadgil, Ashok

    2010-10-26

    A method for low-cost arsenic removal from drinking water using chemically prepared bottom ash pre-treated with ferrous sulfate and then sodium hydroxide. Deposits on the surface of particles of bottom ash form of activated iron adsorbent with a high affinity for arsenic. In laboratory tests, a miniscule 5 grams of pre-treated bottom ash was sufficient to remove the arsenic from 2 liters of 2400 ppb (parts per billion) arsenic-laden water to a level below 50 ppb (the present United States Environmental Protection Agency limit). By increasing the amount of pre-treated bottom ash, even lower levels of post-treatment arsenic are expected. It is further expected that this invention supplies a very low-cost solution to arsenic poisoning for large population segments.

  10. Postoperative environmental anesthetic vapour concentrations following removal of the airway device in the operating room versus the postanesthesia care unit.

    Science.gov (United States)

    Cheung, Sara K; Özelsel, Timur; Rashiq, Saifee; Tsui, Ban C

    2016-09-01

    This study was designed to compare waste anesthetic gas (WAG) concentrations within patients' breathing zones after removal of the patient's airway device in the postanesthesia care unit (PACU) vs in the operating room (OR). Following Research Ethics Board approval and patient consent, we recruited patients undergoing surgery who received volatile anesthesia via an endotracheal tube or supraglottic airway. Patients had their airway device removed in the OR or in the PACU depending on the attending anesthesiologist's preference. Upon the patient's arrival in the PACU, concentrations of exhaled sevoflurane and desflurane were measured at their breathing zone (i.e., 15 cm from the patient's mouth and nose) using a single-beam infrared spectrophotometer. Seventy patients were recruited during the five-month study period. The median [interquartile range] WAG levels in the patients' breathing zones were higher when their airway devices were removed in the PACU vs in the OR. The WAG levels for sevoflurane were 0.7 [0.4-1.1] parts per million (ppm) vs 0.5 [0.4-0.7] ppm, respectively; median difference, 0.3; 95% confidence interval (CI), 0.1 to 0.6; P = 0.04. The WAG levels for desflurane were 2.4 [1.2-3.4] ppm vs 4.1 [2.5-5.2] ppm, respectively; median difference, 1.5; 95% CI, 0.3 to 2.7; P = 0.04. After a volatile-based anesthetic, our results suggest that removal of the airway device in the PACU vs in the OR increases the amount of waste anesthetic gas in a patient's breathing zone and thus potentially in the PACU nurse's working zone.

  11. Kinetics of the removal of mono-chlorobenzene vapour from waste gases using a trickle bed air biofilter.

    Science.gov (United States)

    Mathur, Anil K; Sundaramurthy, J; Balomajumder, C

    2006-10-11

    The performance of a trickle bed air biofilter (TBAB) in the removal of mono-chlorobenzene (MCB) was evaluated in concentrations varying from 0.133 to 7.187 g m(-3) and at empty bed residence time (EBRT) varying from 37.7 to 188.52 s. More than 90% removal efficiency in the trickle bed air biofilter was achieved for the inlet MCB concentration up to 1.069 g m(-3) and EBRT less than 94.26 s. The trickle bed air biofilter was constructed with coal packing material, inoculated with a mixed consortium of activated sludge obtained from sewage treatment plant. The continuous performance of the removal of MCB in the trickle bed air biofilter was monitored for various gas concentrations, gas flow rates, and empty bed residence time. The experiment was conducted for a period of 75 days. The trickle bed air biofilter degrading MCB with an average elimination capacity of 80 g m(-3) h(-1) was obtained. The effect of starvation was also studied. After starvation period of 8 days, the degradation was low but recovered within a short period of time. Using macrokinetic determination method, the Michaelis-Menten kinetic constant K(m) and maximum reaction rate, r(max) evaluated as 0.121 g m(-3) s(-1) and 7.45 g m(-3), respectively.

  12. Experimental study to distinguish the effects of methanol slip and water vapour on a high temperature PEM fuel cell at different operating conditions

    DEFF Research Database (Denmark)

    Thomas, Sobi; Vang, Jakob Rabjerg; Araya, Samuel Simon

    2017-01-01

    The objective of this paper is to separate out the effects of methanol and water vapour on a high temperature polymer electrolyte membrane fuel cell under different temperatures (160°C and 180°C) and current densities (0.2Acm-2, 0.4Acm-2 and 0.6Acm-2). The degradation rates at the different curre...

  13. Continuous measurements of stable isotopes of carbon dioxide and water vapour in an urban atmosphere: isotopic variations associated with meteorological conditions.

    Science.gov (United States)

    Wada, Ryuichi; Matsumi, Yutaka; Nakayama, Tomoki; Hiyama, Tetsuya; Fujiyoshi, Yasushi; Kurita, Naoyuki; Muramoto, Kenichiro; Takanashi, Satoru; Kodama, Naomi; Takahashi, Yoshiyuki

    2017-12-01

    Isotope ratios of carbon dioxide and water vapour in the near-surface air were continuously measured for one month in an urban area of the city of Nagoya in central Japan in September 2010 using laser spectroscopic techniques. During the passages of a typhoon and a stationary front in the observation period, remarkable changes in the isotope ratios of CO 2 and water vapour were observed. The isotope ratios of both CO 2 and water vapour decreased during the typhoon passage. The decreases can be attributed to the air coming from an industrial area and the rainout effects of the typhoon, respectively. During the passage of the stationary front, δ 13 C-CO 2 and δ 18 O-CO 2 increased, while δ 2 H-H 2 Ov and δ 18 O-H 2 Ov decreased. These changes can be attributed to the air coming from rural areas and the air surrounding the observational site changing from a subtropical air mass to a subpolar air mass during the passage of the stationary front. A clear relationship was observed between the isotopic CO 2 and water vapour and the meteorological phenomena. Therefore, isotopic information of CO 2 and H 2 Ov could be used as a tracer of meteorological information.

  14. Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

    Science.gov (United States)

    Di Girolamo, Paolo; Flamant, Cyrille; Cacciani, Marco; Summa, Donato; Stelitano, Dario; Richard, Evelyne; Ducrocq, Véronique; Fourrie, Nadia; Said, Frédérique

    2017-02-01

    Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) Special Observation Period 1 (SOP1). Low-level wind reversals associated with these transitions are found to have a strong impact on water vapour transport, leading to a large variability of the water vapour vertical and horizontal distribution. The high spatial and temporal resolution of the lidar data allow to monitor the time evolution of the three-dimensional water vapour field during these transitions from predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow, allowing to identify the quite sharp separation between these flows, which is also quite well captured by the mesoscale models.

  15. Properties of alumina films prepared by metal-organic chemical vapour deposition at atmospheric pressure in hte presence of small amounts of water

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Rem, J.B.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films were deposited on stainless steel, type AISI 304. The deposition process was carried out in nitrogen with low partial pressures of water (0–2.6 × 10−2 kPa (0−0.20 mmHg)) by metal-organic chemical vapour deposition (MOCVD) with aluminium-tri-sec-butoxide (ATSB) as the precursor.

  16. Water removal characteristics of parallel serpentine channels

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, K.; Zhou, B.; Quan, P. [Windsor Univ., ON (Canada). Dept. of Mechanical, Automotive and Materials Engineering

    2005-07-01

    A study was conducted in which the liquid water behaviours in parallel serpentine channels with manifolds on the cathode side of a proton exchange membrane (PEM) fuel cell stack were examined. A 3-dimensional, unsteady two-phase flow model within the commercial computational fluid dynamics software package FLUENT was used. Membrane electrode assemblies (MEA) were placed on different sides in the numerical analysis. Several water management issues were identified for this type of fuel cell stack by examining the flow behaviours of liquid water and airflow velocity fields. It was shown that water in the outflow manifold could be blocked by air streams from the gas flow channels, with water flowing continuously into the outflow manifold. It was also shown that the pressure drop along all the unit cells can never increase or decrease at the same pace. Water which adheres to the end wall of both the inlet and outlet manifolds is difficult to remove. It was suggested that faster water drainage can be achieved by keeping the MEA side of the gas flow channels close to the outlet of the outflow manifold. It was also suggested that the collecting and separating effect at the serpentine gas flow channels could improve the water drainage. 8 refs., 10 figs.

  17. Relationships of solar radiation and vapour pressure deficit with photosynthesis and water relations in dry-land pigeon pea

    International Nuclear Information System (INIS)

    Subramanian, V.B.; Venkateswarlu, S.; Maheswari, M.; Sankar, G.R.M.

    1994-01-01

    A study was undertaken to compare the relationships of photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) with carbon assimilation and water relations of dry-land pigeon pea at the vegetative and reproductive phases. Photosynthetic rate (Pn), transpiration rate (T), leaf water potential (wL), and stomatal conductance (gs) were measured at 7- to 10-day intervals from 1 month after seedling until a fortnight before harvest during two seasons. Generally, Pn, T, and gs were higher and wL was lower during the reproductive than during the vegetative phase. At high PAR and VPD, Pn, T, wL, and gs decreased. The decrease in the T at high PAR was smaller during the reproductive phase. Growth of dry-land pigeon pea was affected not only during periods of water stress which was associated with high PAR and high VPD but also under conditions of favourable plant water status which were associated with less than optimal levels of PAR. It also showed transpiration efficiency (TE) was lower during the pod-filling than during the vegetative phase, when PAR was optimum

  18. REDUCING ARSENIC LEVELS IN DRINKING WATER DURING IRON REMOVAL PROCESSES

    Science.gov (United States)

    The presentation provides an overview of iron removal technology for the removal of arsenic from drinking water. The presentation is divided into several topic topics: Arsenic Chemistry, Treatment Selection, Treatment Options, Case Studies and Iron Removal Processes. Each topic i...

  19. Airborne differential absorption lidar for water vapour measurements in the upper troposphere and lower stratosphere in the spectral region around 940 nm

    Energy Technology Data Exchange (ETDEWEB)

    Poberaj, G.

    2000-07-01

    Two all-solid-state laser systems were developed and studied in detail to optimise their performance for an airborne water vapour differential absorption lidar (DIAL). Their special features are high average output powers and excellent spectral properties in the 940-nm spectral region relevant for monitoring very low water vapour contents in the upper troposphere and lower stratosphere. One system is an injection-seeded pulsed Ti:sapphire ring laser with a spectral bandwidth of 105 MHz and an average power of 1.1 W. The other system is an injection-seeded optical parametric oscillator (OPO) in a ring configuration. Using KTP as nonlinear crystal, a signal output with a spectral bandwidth of 140 MHz and an average power of 1.2 W was achieved. Both systems, the Ti:sapphire ring laser and the KTP OPO, possess spectral purity values higher than 99%. The pump source for these systems is a frequency doubled diode-pumped Nd:YAG laser operating at a repetition rate of 100 Hz. The KTP OPO system has been used as a transmitter in a new airborne water vapour DIAL instrument. For the first time, measurements of two-dimensional water vapour distributions with a high vertical (500 m) and horizontal (20 km) resolution across several potential vorticity streamers were performed. Very low water vapour mixing ratios (10-50 ppmv) and strong gradients were observed in the tropopause region. The sensitivity of the DIAL instrument in the centre of a stratospheric intrusion ranges from 3% in the near field to 12% in the far field (4 km). The first comparison experiments with in situ measuring instruments show a good agreement. Considerable differences are found between DIAL measurements and data obtained from the ECMWF operational analyses and a mesoscale numerical model. (orig.)

  20. Removal of mercury from water using pottery

    International Nuclear Information System (INIS)

    Helal, A.A.A.

    2006-01-01

    In a previous study, the sorption of radiocobalt by powdered pottery materials was investigated. The use of these materials as immobilization matrix for liquid radioactive waste requires the employment of pottery vessels. Therefore, the present study aims to give detailed investigations of the decontamination of radionuclides and toxic elements using pottery containers. These investigations are equally useful to elucidate how far these vessels can be utilized for water purification through decontamination of toxic and heavy metals. The radionuclide or heavy metal removal capability using pottery pots, as low cost sorbents, has been investigated for both radioactive ( 203 Hg) and stable mercury. The results indicated that Hg 2+ is better removed by pottery from neutral to alkaline solutions. The capacity of the used pottery container (100 ml in volume) for complete removal of mercury was found to reach 3 x 10 -4 mol/l, and the time needed was 8 hours. The sorption process was suggested to occur via adsorption and ion exchange. The effect of presence of humic or fulvic acid, as ligands abundant in water, is also investigated. The results imply that, in absence of humic or fulvic acid the sorption follows the expected behaviour, i.e. sorption sites with similar affinity for mercury. In presence of humic or fulvic acid, additional sorption sites are available by the organic molecule when it is associated to the pottery. (orig.)

  1. Organically modified clay removes oil from water

    International Nuclear Information System (INIS)

    Alther, G.R.

    1995-01-01

    When bentonite or other clays and zeolite are modified with quaternary amines, they become organophilic. Such modified bentonites are used to remove mechanically emulsified oil and grease, and other sparingly soluble organics. Types of oil found in water can include fats, lubricants, cutting fluids, heavy hydrocarbons such as tars, grease, crude oil, diesel oils; and light hydrocarbons such as kerosene, jet fuel, and gasoline. If the organoclay is granulated, it is placed into a liquid phase carbon filter vessel to remove FOGs (Free Oil and Grease) and chlorinated hydrocarbons. In this application the clay is mixed with anthrazite to prevent early plugging of the filter by oil or grease droplets. In batch systems a powdered organoclay is employed. Organoclay removes mechanically emulsified oil and grease at 5--7 times the rate of activated carbon, or 50% of its dry weight. Oil and grease and other large sparingly soluble chlorinated hydrocarbons and NOMs (Natural Organic Matter) blind the pores of activated carbon (and ion-exchange resins), reducing its effectiveness significantly. It is therefore economically advantageous for the end user to prepolish the water before it enters carbon vessels. Operating costs can often be reduced by 50% or more

  2. Can Microalgae Remove Pharmaceutical Contaminants from Water?

    Science.gov (United States)

    Xiong, Jiu-Qiang; Kurade, Mayur B; Jeon, Byong-Hun

    2018-01-01

    The increase in worldwide water contamination with numerous pharmaceutical contaminants (PCs) has become an emerging environmental concern due to their considerable ecotoxicities and associated health issues. Microalgae-mediated bioremediation of PCs has recently gained scientific attention, as microalgal bioremediation is a solar-power driven, ecologically comprehensive, and sustainable reclamation strategy. In this review, we comprehensively describe the current research on the possible roles and applications of microalgae for removing PCs from aqueous media. We summarize several novel approaches including constructing microbial consortia, acclimation, and cometabolism for enhanced removal of PCs by microalgae, which would improve practical feasibility of these technologies. Some novel concepts for degrading PCs using integrated processes and genetic modifications to realize algal-based bioremediation technologies are also recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Organically modified clay removes oil from water

    International Nuclear Information System (INIS)

    Alther, G.R.

    1995-01-01

    When bentonite or other clays and zeolites are modified with quaternary amines, they become organophilic. Such modified bentonites are used to remove mechanically emulsified oil and grease, and other sparingly soluble organics. If the organoclay is granulated, it is placed into a liquid phase carbon filter vessel to remove FOG's and chlorinated hydrocarbons. In this application the clay is mixed with anthrazite to prevent early plugging of the filter by oil or grease droplets. In batch systems a powered organoclay is employed. Types of oil found in water can include fats, lubricants, cutting fluids, heavy hydrocarbons such as tars, grease, crude oil, diesel oils; and light hydrocarbons such as kerosene, jet fuel, and gasoline

  4. Water vapour in the middle atmosphere of Venus:. An improved treatment of the Venera 15 ir spectra

    Science.gov (United States)

    Ignatiev, N. i.; Moroz, V. i.; Zasova, L. V.; Khatuntsev, I. v.

    1999-08-01

    In 1983, spectra of Venus in the region of 6-40 μm were measured by means of the Fourier Spectrometer aboard the Venera 15 orbiter. It covered local solar times from 4 am to 10 am and from 4 pm to 10 pm in the latitude range from 65°S up to 87°N. The results of an extended processing and analysis of these data are presented. Time and spatial variations of the water vapour were found. Most of the measurements fall in the range of 5-15 ppm, which is close to earlier results. The effective altitude of sounding is approximately equal to the altitude where the optical depth τ = 1. In the northern hemisphere, which was mainly covered by the measurements, two latitude regions can be distinguished; (A) 20° 60°, which are characterised by different altitudes of the level of τ = 1, 62 and 55 km respectively. Mean mixing ratios near this level in the two regions are almost the same, but the partial pressures and mass densities in the region (B) are 2-4 times greater than those in region (A). In region (A) a weak maximum was detected near 10 am local solar time (17 ppm at φ = 35°) and a minimum-near 10 pm (2ppm at φ = 30°). Region (B) is of inhomogeneous structure, and the retrieved mixing ratio has greater uncertainty and may probably change from the low values up to 30 ppm. In region (A) the water vapour mass density at the level of τ = 1 is 2-4 times greater than the mean density of the water contained in aerosol particles, while in region (B) this ratio may vary in the limits 0.5-5. Although the retrieval of H2O mixing ratio altitude profile from the Venera 15 data appeared to be impossible, indirect indications were found that at least in region (A) the mixing ratio decreases with altitude.

  5. Water vapour solubility and conductivity study of the proton conductor BaCe(0.9 − x)ZrxY0.1O(3 − δ)

    DEFF Research Database (Denmark)

    Ricote, Sandrine; Bonanos, Nikolaos; Caboche, G:

    2009-01-01

    The perovskite BaCe(0.9 − x)ZrxY0.1O(3 − δ) has been prepared by solid state reaction at 1400 °C and conventional sintering at 1700 °C. Water uptake experiments performed between 400 and 600 °C, at a water vapour pressure of 0.02 atm, provide data on the concentration of protons incorporated in t...

  6. Gravimetric phenotyping of whole plant transpiration responses to atmospheric vapour pressure deficit identifies genotypic variation in water use efficiency.

    Science.gov (United States)

    Ryan, Annette C; Dodd, Ian C; Rothwell, Shane A; Jones, Ros; Tardieu, Francois; Draye, Xavier; Davies, William J

    2016-10-01

    There is increasing interest in rapidly identifying genotypes with improved water use efficiency, exemplified by the development of whole plant phenotyping platforms that automatically measure plant growth and water use. Transpirational responses to atmospheric vapour pressure deficit (VPD) and whole plant water use efficiency (WUE, defined as the accumulation of above ground biomass per unit of water used) were measured in 100 maize (Zea mays L.) genotypes. Using a glasshouse based phenotyping platform with naturally varying VPD (1.5-3.8kPa), a 2-fold variation in WUE was identified in well-watered plants. Regression analysis of transpiration versus VPD under these conditions, and subsequent whole plant gas exchange at imposed VPDs (0.8-3.4kPa) showed identical responses in specific genotypes. Genotype response of transpiration versus VPD fell into two categories: 1) a linear increase in transpiration rate with VPD with low (high WUE) or high (low WUE) transpiration rate at all VPDs, 2) a non-linear response with a pronounced change point at low VPD (high WUE) or high VPD (low WUE). In the latter group, high WUE genotypes required a significantly lower VPD before transpiration was restricted, and had a significantly lower rate of transpiration in response to VPD after this point, when compared to low WUE genotypes. Change point values were significantly positively correlated with stomatal sensitivity to VPD. A change point in stomatal response to VPD may explain why some genotypes show contradictory WUE rankings according to whether they are measured under glasshouse or field conditions. Furthermore, this novel use of a high throughput phenotyping platform successfully reproduced the gas exchange responses of individuals measured in whole plant chambers, accelerating the identification of plants with high WUE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Effect of surface albedo, water vapour, and atmospheric aerosols on the cloud-free shortwave radiative budget in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Di Biagio, C. [ENEA, Laboratory for Earth Observations and Analyses, Rome (Italy); University of Siena, Department of Earth Science, Siena (Italy); Di Sarra, A. [ENEA, Laboratory for Earth Observations and Analyses, Rome (Italy); Eriksen, P. [Danish Climate Centre, DMI, Danish Meteorological Institute, Copenhagen (Denmark); Ascanius, S.E. [DMI, Danish Meteorological Institute, Qaanaaq (Greenland); Muscari, G. [INGV, Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy); Holben, B. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2012-08-15

    This study is based on ground-based measurements of downward surface shortwave irradiance (SW), columnar water vapour (wv), and aerosol optical depth ({tau}) obtained at Thule Air Base (Greenland) in 2007-2010, together with MODIS observations of the surface shortwave albedo (A). Radiative transfer model calculations are used in combination with measurements to separate the radiative effect of A ({Delta}SW{sub A}), wv ({Delta}SW{sub wv}), and aerosols ({Delta}SW{sub {tau}}) in modulating SW in cloud-free conditions. The shortwave radiation at the surface is mainly affected by water vapour absorption, which produces a reduction of SW as low as -100 Wm{sup -2} (-18%). The seasonal change of A produces an increase of SW by up to +25 Wm{sup -2} (+4.5%). The annual mean radiative effect is estimated to be -(21-22) Wm{sup -2} for wv, and +(2-3) Wm{sup -2} for A. An increase by +0.065 cm in the annual mean wv, to which corresponds an absolute increase in {Delta}SW{sub wv} by 0.93 Wm{sup -2} (4.3%), has been observed to occur between 2007 and 2010. In the same period, the annual mean A has decreased by -0.027, with a corresponding decrease in {Delta}SW{sub A} by 0.41 Wm{sup -2} (-14.9%). Atmospheric aerosols produce a reduction of SW as low as -32 Wm{sup -2} (-6.7%). The instantaneous aerosol radiative forcing (RF{sub {tau}}) reaches values of -28 Wm{sup -2} and shows a strong dependency on surface albedo. The derived radiative forcing efficiency (FE{sub {tau}}) for solar zenith angles between 55 and 70 is estimated to be (-120.6 {+-} 4.3) for 0.1 < A < 0.2, and (-41.2 {+-} 1.6) Wm{sup -2} for 0.5 < A < 0.6. (orig.)

  8. Accuracy assessment of water vapour measurements from in situ and remote sensing techniques during the DEMEVAP 2011 campaign at OHP

    Directory of Open Access Journals (Sweden)

    O. Bock

    2013-10-01

    Full Text Available The Development of Methodologies for Water Vapour Measurement (DEMEVAP project aims at assessing and improving humidity sounding techniques and establishing a reference system based on the combination of Raman lidars, ground-based sensors and GPS. Such a system may be used for climate monitoring, radiosonde bias detection and correction, satellite measurement calibration/validation, and mm-level geodetic positioning with Global Navigation Satellite Systems. A field experiment was conducted in September–October 2011 at Observatoire de Haute-Provence (OHP. Two Raman lidars (IGN mobile lidar and OHP NDACC lidar, a stellar spectrometer (SOPHIE, a differential absorption spectrometer (SAOZ, a sun photometer (AERONET, 5 GPS receivers and 4 types of radiosondes (Vaisala RS92, MODEM M2K2-DC and M10, and Meteolabor Snow White participated in the campaign. A total of 26 balloons with multiple radiosondes were flown during 16 clear nights. This paper presents preliminary findings from the analysis of all these data sets. Several classical Raman lidar calibration methods are evaluated which use either Vaisala RS92 measurements, point capacitive humidity measurements, or GPS integrated water vapour (IWV measurements. A novel method proposed by Bosser et al. (2010 is also tested. It consists in calibrating the lidar measurements during the GPS data processing. The methods achieve a repeatability of 4–5%. Changes in the calibration factor of IGN Raman lidar are evidenced which are attributed to frequent optical re-alignments. When modelling and correcting the changes as a linear function of time, the precision of the calibration factors improves to 2–3%. However, the variations in the calibration factor, and hence the absolute accuracy, between methods and types of reference data remain at the level of 7%. The intercomparison of radiosonde measurements shows good agreement between RS92 and Snow White measurements up to 12 km. An overall dry bias is found

  9. Spatial Heterodyne Observations of Water (SHOW) vapour in the upper troposphere and lower stratosphere from a high altitude aircraft: Modelling and sensitivity analysis

    Science.gov (United States)

    Langille, J. A.; Letros, D.; Zawada, D.; Bourassa, A.; Degenstein, D.; Solheim, B.

    2018-04-01

    A spatial heterodyne spectrometer (SHS) has been developed to measure the vertical distribution of water vapour in the upper troposphere and the lower stratosphere with a high vertical resolution (∼500 m). The Spatial Heterodyne Observations of Water (SHOW) instrument combines an imaging system with a monolithic field-widened SHS to observe limb scattered sunlight in a vibrational band of water (1363 nm-1366 nm). The instrument has been optimized for observations from NASA's ER-2 aircraft as a proof-of-concept for a future low earth orbit satellite deployment. A robust model has been developed to simulate SHOW ER-2 limb measurements and retrievals. This paper presents the simulation of the SHOW ER-2 limb measurements along a hypothetical flight track and examines the sensitivity of the measurement and retrieval approach. Water vapour fields from an Environment and Climate Change Canada forecast model are used to represent realistic spatial variability along the flight path. High spectral resolution limb scattered radiances are simulated using the SASKTRAN radiative transfer model. It is shown that the SHOW instrument onboard the ER-2 is capable of resolving the water vapour variability in the UTLS from approximately 12 km - 18 km with ±1 ppm accuracy. Vertical resolutions between 500 m and 1 km are feasible. The along track sampling capability of the instrument is also discussed.

  10. Developing a western Siberia reference site for tropospheric water vapour isotopologue observations obtained by different techniques (in situ and remote sensing

    Directory of Open Access Journals (Sweden)

    K. Gribanov

    2014-06-01

    water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recently developed infrared laser spectrometers allow for continuous in situ measurements of surface water vapour δDv and δ18Ov. So far, very few intercomparisons of measurements conducted using different techniques have been achieved at a given location, due to difficulties intrinsic to the comparison of integrated with local measurements. Nudged simulations conducted with high-resolution isotopically enabled general circulation models (GCMs provide a consistent framework for comparison with the different types of observations. Here, we compare simulations conducted with the ECHAM5-wiso model with two types of water vapour isotopic data obtained during summer 2012 at the forest site of Kourovka, western Siberia: hourly ground-based FTIR total atmospheric columnar δDv amounts, and in situ hourly Picarro δDv measurements. There is an excellent correlation between observed and predicted δDv at surface while the comparison between water column values derived from the model compares well with FTIR estimates.

  11. Comparisons of xylem sap flow and water vapour flux at the stand level and derivation of canopy conductance for Scots pine

    Science.gov (United States)

    Granier, A.; Biron, P.; Köstner, B.; Gay, L. W.; Najjar, G.

    1996-03-01

    Simultaneous measurements of xylem sap flow and water vapour flux over a Scots pine ( Pinus sylvestris) forest (Hartheim, Germany), were carried out during the Hartheim Experiment (HartX), an intensive observation campaign of the international programme REKLIP. Sap flow was measured every 30 min using both radial constant heating (Granier, 1985) and two types of Cermak sap flowmeters installed on 24 trees selected to cover a wide range of the diameter classes of the stand (min 8 cm; max 17.5 cm). Available energy was high during the observation period (5.5 to 6.9 mm.day-1), and daily cumulated sap flow on a ground area basis varied between 2.0 and 2.7 mm day-1 depending on climate conditions. Maximum hourly values of sap flow reached 0.33 mm h-1, i.e., 230 W m-2. Comparisons of sap flow with water vapour flux as measured with two OPEC (One Propeller Eddy Correlation, University of Arizona) systems showed a time lag between the two methods, sap flow lagging about 90 min behind vapour flux. After taking into account this time lag in the sap flow data set, a good agreement was found between both methods: sap flow = 0.745* vapour flux, r 2 = 0.86. The difference between the two estimates was due to understory transpiration. Canopy conductance ( g c ) was calculated from sap flow measurements using the reverse form of Penman-Monteith equation and climatic data measured 4 m above the canopy. Variations of g c were well correlated ( r 2 = 0.85) with global radiation ( R) and vapour pressure deficit ( vpd). The quantitative expression for g c = f ( R, vpd) was very similar to that previously found with maritime pine ( Pinus pinaster) in the forest of Les Landes, South Western France.

  12. Fluoride removal from water by nano filtration

    International Nuclear Information System (INIS)

    Bejaoui, Imen; Mnif, Amine; Hamrouni, Bechir

    2009-01-01

    As any oligo element, fluoride is necessary and beneficial for human health to low concentrations, but an excess amount of fluoride ions in drinking water has been known to cause undesirable effects, especially tooth and bones fluoro sis. The maximum acceptable concentration of fluoride in drinking water was fixed by the World Health Organization according to the climate in the range of 1 mg.L -1 to 1,2 mg.L -1 . Many methods have been used to remove fluoride from water such as precipitation, adsorption, electrocoagulation and membrane processes. Technologies using membrane processes are being used in many applications, particularly for brackish water desalination. Nano filtration seems to be the best process for a good selective defluorination of fluorinated waters. The main objective of this work was to investigate the retention of fluoride anions by nano filtration. The first part of this study deals with the characterisation of the NF HL2514TF membrane. The influence of various experimental parameters such as initial fluoride content, feed pressure, permeate flux, ionic strength, type of cation associated to fluoride and pH were studied in the second part. Results show that the retention order for the salts tested was TR(Na 2 SO 4 ) > TR(CaCl 2 ) > TR(NaCl), showing a retention sequence inversely proportional to the salt diffusion coefficients in water. It was also shown that charge effects could not be neglected, and a titration experiments confirmed that the NF membrane carry a surplus of negatively charged groups. Fluoride retention exceeds 60 pour cent, and increases with increasing concentration, where the rejection mechanism is related to the dielectric effects. Speigler-Kedem model was applied to experimental results in the aim to determine phenomenological parametersσand P s respectively, the reflexion coefficient of the membrane and the solute permeability of ions. The convective and diffusive parts of the mass transfer were quantified with

  13. Development of a novel smoke-flavoured salmon product by sodium replacement using water vapour permeable bags.

    Science.gov (United States)

    Rizo, Arantxa; Fuentes, Ana; Barat, José M; Fernández-Segovia, Isabel

    2018-05-01

    Food manufacturers need to reduce sodium content to meet consumer and public health demands. In the present study, the use of sodium-free (SF) salt and KCl to develop a novel smoke-flavoured salmon product with reduced sodium content was evaluated. Fifty percent of NaCl was replaced with 50% of SF salt or 50% KCl in the salmon smoke-flavouring process, which was carried out using water vapour permeable bags. Triangle tests showed that samples with either SF salt or KCl were statistically similar to the control samples (100% NaCl). Because no sensorial advantage in using SF salt was found compared to KCl and given the lower price of KCl, the KCl-NaCl samples were selected for the next phase. The changes of physicochemical and microbial parameters in smoke-flavoured salmon during 42 days showed that partial replacement of NaCl with KCl did not significantly affect the quality and shelf-life of smoke-flavoured salmon, which was over 42 days. Smoke-flavoured salmon with 37% sodium reduction was developed without affecting the sensory features and shelf-life. This is an interesting option for reducing the sodium content in such products to help meet the needs set by both health authorities and consumers. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Comparison of Lyman-alpha and LI-COR infrared hygrometers for airborne measurement of turbulent fluctuations of water vapour

    Science.gov (United States)

    Lampert, Astrid; Hartmann, Jörg; Pätzold, Falk; Lobitz, Lennart; Hecker, Peter; Kohnert, Katrin; Larmanou, Eric; Serafimovich, Andrei; Sachs, Torsten

    2018-05-01

    To investigate if the LI-COR humidity sensor can be used as a replacement of the Lyman-alpha sensor for airborne applications, the measurement data of the Lyman-alpha and several LI-COR sensors are analysed in direct intercomparison flights on different airborne platforms. One vibration isolated closed-path and two non-isolated open-path LI-COR sensors were installed on a Dornier 128 twin engine turbo-prop aircraft. The closed-path sensor provided absolute values and fluctuations of the water vapour mixing ratio in good agreement with the Lyman-alpha. The signals of the two open-path sensors showed considerable high-frequency noise, and the absolute value of the mixing ratio was observed to drift with time in this vibrational environment. On the helicopter-towed sensor system Helipod, with very low vibration levels, the open-path LI-COR sensor agreed very well with the Lyman-alpha sensor over the entire frequency range up to 3 Hz. The results show that the LI-COR sensors are well suited for airborne measurements of humidity fluctuations, provided that a vibrationless environment is given, and this turns out to be more important than close sensor spacing.

  15. Water, vapour and heat transport in concrete cells for storing radioactive waste

    Science.gov (United States)

    Carme Chaparro, M.; W. Saaltink, Maarten

    2016-08-01

    Water is collected from a drain situated at the centre of a concrete cell that stores radioactive waste at 'El Cabril', which is the low and intermediate level radioactive waste disposal facility of Spain. This indicates flow of water within the cell. 2D numerical models have been made in order to reproduce and understand the processes that take place inside the cell. Temperature and relative humidity measured by sensors in the cells and thermo-hydraulic parameters from laboratory test have been used. Results show that this phenomenon is caused by capillary rise from the phreatic level, evaporation and condensation within the cell produced by temperature gradients caused by seasonal temperature fluctuations outside. At the centre of the cell, flow of gas and convection also play a role. Three remedial actions have been studied that may avoid the leakage of water from the drain.

  16. Thickness and structure of the water film deposited from vapour on calcite surfaces

    DEFF Research Database (Denmark)

    Bohr, Jakob; Wogelius, Roy A.; Morris, Peter M.

    2010-01-01

    Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from......Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from...

  17. Online analytical investigations on solvent-, temperature- and water vapour-induced phase transformations of citric acid

    Energy Technology Data Exchange (ETDEWEB)

    Helmdach, L.; Ulrich, J. [Martin-Luther-Universitaet Halle-Wittenberg, Zentrum fuer Ingenieurwissenschaft, Verfahrenstechnik/TVT, Halle (Saale) (Germany); Feth, M.P. [Sanofi-Aventis Deutschland GmbH, Chemical and Process Development Frankfurt Chemistry, Frankfurt (Germany)

    2012-09-15

    It was demonstrated exemplarily for the crystallization of citric acid that the usage of an ultrasound device as well as Raman spectroscopy enables the inline measurement and the control of phase transitions. The influence of different solvent compositions (water and ethanol-water) on the crystallization of citric acid was investigated. By increasing the ethanol content the transformation point was shifted towards higher temperatures. In addition, a strong impact on the nucleation point as well as on the crystal habit was detected in ethanol-water mixtures. The results lead to the assumption that a citric acid solvate exists, which is, however, highly unstable upon isolation from mother liquor and converts fast into the known anhydrate or monohydrate forms of citric acid. The presence of such a solvate, however, could not be proven during this study. Furthermore, factors such as temperature and humidity which might influence the phase transition of the solid product were analyzed by Hotstage-Raman Spectroscopy and Water Vapor Sorption Gravimetry-Dispersive Raman Spectroscopy. Both, temperature as well as humidity show a strong influence on the behaviour of CAM. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Oxidation of X20 in Water Vapour: The Effect of Temperature and Oxygen Partial Pressure

    DEFF Research Database (Denmark)

    Hansson, Anette Nørgaard; Montgomery, Melanie; Somers, Marcel A. J.

    2009-01-01

    The oxidation behaviour of X20 in various mixtures of water, oxygen and hydrogen was investigated at temperatures between 500 C and 700 C (time: 336 h). The samples were characterised using reflected light microscopy and scanning electron microscopy equipped with energy dispersive spectroscopy...

  19. Carbon dioxide and water vapour exchange from understory species in boreal forest.

    NARCIS (Netherlands)

    Heijmans, M.M.P.D.; Arp, W.J.; Chapin, F.S.

    2004-01-01

    Although recent eddy covariance measurements in boreal forests provide CO2 and energy exchange data for the whole ecosystem, very little is known about the role of the understory vegetation. We conducted chamber flux measurements in an Alaskan black spruce forest in order to compare CO2 and water

  20. Detection of chemical substances in water using an oxide nanowire transistor covered with a hydrophobic nanoparticle thin film as a liquid-vapour separation filter

    Directory of Open Access Journals (Sweden)

    Taekyung Lim

    2016-08-01

    Full Text Available We have developed a method to detect the presence of small amounts of chemical substances in water, using a Al2O3 nanoparticle thin film covered with phosphonic acid (HDF-PA self-assembled monolayer. The HDF-PA self-assembled Al2O3 nanoparticle thin film acts as a liquid-vapour separation filter, allowing the passage of chemical vapour while blocking liquids. Prevention of the liquid from contacting the SnO2 nanowire and source-drain electrodes is required in order to avoid abnormal operation. Using this characteristic, the concentration of chemical substances in water could be evaluated by measuring the current changes in the SnO2 nanowire transistor covered with the HDF-PA self-assembled Al2O3 nanoparticle thin film.

  1. Renovation and design of double casement windows with regard to the occurrence of water vapour condensation or mould on the interior surface of the window jamb

    Science.gov (United States)

    Kudrnacova, L.; Balik, L.

    2017-10-01

    The condensation of water vapour on the interior surface is an indicator of construction dysfunction or ignoring of the surroundings temperature and relative humidity. This paper deals with analysis of the occurrence of condensation on the jamb of double casement windows (windows with two window casements). More precisely, this is a surface in the interior where water vapour condensation or mould occur. For the renovation of existing double casement windows, there are different solutions based on window design: application of double insulating glazing on the interior window casement, application of double insulating glazing on the exterior casement, or installation of a simple window. We first describe measurement of an existing double casement window located in a mountain cottage. Second, the results and comparison of 2D thermal model of different types of double casement window construction. Also, the external insulation of the peripheral wall was included in the model.

  2. New Sorbents for Removing Arsenic From Water

    Science.gov (United States)

    McConchie, D. M.; Genc-Fuhrman, H.; Clark, M. W.; Caldicott, W.; Davies-McConchie, F. G.

    2004-12-01

    Elevated concentrations of arsenic in the drinking water used in many countries, including some of the poorest developing countries, and recognition that consuming this water can have serious consequences for human health, have led to increased investigations of ways to obtain safe water supplies. Finding new groundwater resources is a possible solution but this is a costly strategy that has no guarantee of success, particularly in areas where water is already a scarce commodity. The alternative is to treat water that is already available, but existing technologies are usually too expensive, too difficult to operate and maintain, or not completely effective when used in less developed countries or remote areas. There is therefore, an urgent need to find a simple and effective but inexpensive sorbent for arsenic that can be used to treat large volumes of water under less than ideal conditions. In this paper we present the results of field and laboratory trials that used a new, highly cost-effective, sorbent to remove arsenic from contaminated water. BauxsolT is the name given to the cocktail of minerals prepared by treating caustic bauxite refinery residues with Mg and Ca to produce a substance with a reaction pH of about 8.5, a high acid neutralizing capacity and an excellent ability to trap trace metals, metalloids and some other ionic species. The trapped ions are tightly bound by processes that include; precipitation of low solubility neoformational minerals, isomorphous substitution, solid-state diffusion, and adsorption; it is also an excellent flocculant. Although ordinary BauxsolT has an excellent ability to bind arsenate, and to a lesser extent arsenite, this ability can be further increased for particular water types by using activated BauxsolT or BauxsolT combined with small amounts of other reagents. Field trials conducted at the Gilt Edge Mine, South Dakota, showed that the addition of BauxsolT to highly sulfidic waste rock reduced the arsenic

  3. Influence of capillary forces on water injection into hot rock, saturated with superheated vapour

    Energy Technology Data Exchange (ETDEWEB)

    Tsypkin, G.G. [Institute for Problems in Mechanics, RAS, Vernadskogo Ave. 101, 119420 Moscow (Russian Federation); Calore, C. [Istituto di Geoscienze e Georisorse - CNR, Sezione di Firenze, via La Pira 4, 50121 Florence (Italy)

    2007-07-15

    The results of a theoretical study and numerical analysis of the role of capillary pressure of cold water injection into depleted geothermal reservoirs are presented. A simplified 1-D mathematical model is developed, that describes the motion of a sharp vaporization front. Some asymptotic estimates for a wide range of parameters are given and a similarity solution is derived. Analytical results are then compared with those obtained from the numerical reservoir simulator TOUGH2, showing a good agreement between the two. (author)

  4. [The method to remove nitrite from tap water by tea].

    Science.gov (United States)

    Lu, M; Chen, L; Xian, H

    1997-03-01

    Drinking water (tap water) is polluted in pipelines by bacteria after long distance transportation. The water contains nitrite (NO2-) which is potentially harmful to human health. The nitrite concentrations range from 0.10 to 2.0 mg/L. Our experiment proved that NO2- could not be removed by boiling, but could be removed by tea. As a natural antioxidant, tea contains several antioxidants, such as ascorbic acid and catechins, which removed NO2- from tap water effectively.

  5. Hydrogen production by high temperature electrolysis of water vapour and nuclear reactors

    International Nuclear Information System (INIS)

    Jean-Pierre Py; Alain Capitaine

    2006-01-01

    This paper presents hydrogen production by a nuclear reactor (High Temperature Reactor, HTR or Pressurized Water Reactor, PWR) coupled to a High Temperature Electrolyser (HTE) plant. With respect to the coupling of a HTR with a HTE plant, EDF and AREVA NP had previously selected a combined cycle HTR scheme to convert the reactor heat into electricity. In that case, the steam required for the electrolyser plant is provided either directly from the steam turbine cycle or from a heat exchanger connected with such cycle. Hydrogen efficiency production is valued using high temperature electrolysis. Electrolysis production of hydrogen can be performed with significantly higher thermal efficiencies by operating in the steam phase than in the water phase. The electrolysis performance is assessed with solid oxide and solid proton electrolysis cells. The efficiency from the three operating conditions (endo-thermal, auto-thermal and thermo-neutral) of a high temperature electrolysis process is evaluated. The technical difficulties to use the gases enthalpy to heat the water are analyzed, taking into account efficiency and technological challenges. EDF and AREVA NP have performed an analysis to select an optimized process giving consideration to plant efficiency, plant operation, investment and production costs. The paper provides pathways and identifies R and D actions to reach hydrogen production costs competitive with those of other hydrogen production processes. (authors)

  6. High-pressure (vapour + liquid) equilibria for ternary systems composed by {(E)-2-hexenal or hexanal + carbon dioxide + water}: Partition coefficient measurement

    International Nuclear Information System (INIS)

    Bejarano, Arturo; López, Pablo I.; Valle, José M. del; Fuente, Juan C. de la

    2015-01-01

    Highlights: • A new apparatus based on a static–analytic method was assembled in this work. • This work reports high-pressure VLE data of (E)-2-hexenal or hexanal + CO 2 + water. • Data includes (CO 2 + water) partition coefficients of (E)-2-hexenal and hexanal. • High separation factors from water (∼10 4 ) were found especially for (E)-2-hexenal. • The data were obtained at T = (313, 323, and 333) K and pressures from (8 to 19) MPa. - Abstract: A new apparatus based on a static–analytic method assembled in this work was utilised to perform high-pressure (vapour + liquid) equilibria measurements of aqueous ternary systems. This work includes values of isothermal partition coefficients between CO 2 and water of two apple aroma constituents, (E)-2-hexenal and hexanal. Additionally, this work reports new experimental (vapour + liquid) equilibria measurements for the ternary systems (CO 2 + (E)-2-hexenal + water) and (CO 2 + hexanal + water), at fixed liquid phase composition (600 mg · kg −1 ), at temperatures of (313, 323 and 333) K and at pressures from (8 to 19) MPa. Vapour liquid interphase was checked and monitored visually for all the systems studied in this work. No liquid immiscibility was observed at the composition, temperatures and pressures studied. In order to suggest reasonable operation conditions for fractionation of aromas with dense carbon dioxide, partition coefficients of the aroma compounds between CO 2 and water along with their separation factors from water were calculated. Partition coefficients of (E)-2-hexenal between CO 2 and water were in the range of (6 to 91) and where found to be near six times higher than those of hexanal (9 to 17). Very high separation factors from water were observed (∼10 4 ) especially for (E)-2-hexenal. The highest separation factor, for both compounds, was found at a temperature of 313 K and pressures from (12 to 14) MPa

  7. Study of transport of oxygen and water vapour between cells in valve regulated lead-acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Culpin, Barry [11 Bluebell Close, Whittle -le -Woods, Chorley PR6 7RH (United Kingdom); Peters, Ken [Battery Design and Manfg Systems, Glenbank, 77 Chatsworth Road, Worsley, Manchester M28 2GG (United Kingdom)

    2006-08-25

    Valve-regulated lead-acid batteries are maintenance free, safer, office compatible, and have higher volume efficiency than conventional designs. They are universally used in telecommunications and uninterruptible power supply systems. With the electrolyte immobilized in the separator or as a gel, it is feasible for a monobloc battery to have cells that are not fully sealed from one another, that is to have a common gas space, with certain attendant benefits. This study demonstrates that small differences in the saturation level, acid strength or operating temperature of the cells in such designs can initiate a cycle that may subsequently result in failure if the movement of oxygen and water vapour between cells is unrestricted. Cells that are initially out-of-balance will go further out-of-balance at an ever-increasing rate. This situation can also arise in monobloc designs with sealed cells if the intercell seal is inadequate or incomplete. Battery failure is associated with a re-distribution of water between the cells with some drying out and having high impedance. The preferential oxygen absorption in those cells produces heavily sulfated negative plates. Results on batteries tested under a range of overcharge conditions and temperatures are presented to illustrate these effects. The rate at which the cycle occurs depends on the initial relative density of the acid, the temperature or saturation imbalance between the cells, and the size of the interconnecting gas space. Batteries operating under a continuous cycling regime, particularly those with high overcharge currents and voltages that generate large volumes of oxygen, are more prone to this type of failure mode than batteries operating under low overcharge, intermittent cycling, or float conditions. (author)

  8. An observational study of air and water vapour convergence over the Bernese Alps, Switzerland, during summertime and the development of isolated thunderstorms

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Edward [Bern Univ. (Switzerland). Inst. of Applied Physics; Lews Castle College, University of the Highlands and Islands, Stornoway, Scotland (United Kingdom); N' Dri Koffi, Ernest; Maetzler, Christian [Bern Univ. (Switzerland). Inst. of Applied Physics

    2012-12-15

    The daytime summer phenomenon of the mesoscale transport of air and water vapour from the Swiss lowlands into the nearby western Alps, leading to orographic convection, is investigated using a range of independent observations. These observations are: Global Positioning System (GPS) integrated water vapour (IWV) data, the TROWARA microwave radiometer, MeteoSwiss ANETZ surface weather station data, the Payerne radiosonde, synoptic analyses for Switzerland and Europe, EUMETSAT and NOAA visible and infrared satellite images, MeteoSwiss operational precipitation radar, photographs and webcam images including time-lapse cloud animations. The intention was to show, using GPS IWV data, that significant differences in IWV may occur between the Swiss plain and nearby Alps during small single-cell Alpine thunderstorm events, and that these may be attributable to regional airflow convergence. Two particular case studies are presented for closer examination: 20 June 2005 and 13 June 2006. On both days, fine and warm weather was followed by isolated orographic convection over the Alps in the afternoon and evening, producing thunderstorms. The thunderstorms investigated were generally small, local, discrete and short-lived phenomena. They were selected for study because of almost stationary position over orography, rendering easy observation because they remained contained within a particular mountain region before dissipating. The results show that large transfers of air and water vapour occur from the Swiss plain to the mountains on such days, with up to a 50% increase in GPS IWV values at individual Alpine stations, coincident with strong airflow convergence in the same locality. (orig.)

  9. Transport coefficients and cross sections for electrons in water vapour: Comparison of cross section sets using an improved Boltzmann equation solution

    Science.gov (United States)

    Ness, K. F.; Robson, R. E.; Brunger, M. J.; White, R. D.

    2012-01-01

    This paper revisits the issues surrounding computation of electron transport properties in water vapour as a function of E/n0 (the ratio of the applied electric field to the water vapour number density) up to 1200 Td. We solve the Boltzmann equation using an improved version of the code of Ness and Robson [Phys. Rev. A 38, 1446 (1988)], facilitating the calculation of transport coefficients to a considerably higher degree of accuracy. This allows a correspondingly more discriminating test of the various electron-water vapour cross section sets proposed by a number of authors, which has become an important issue as such sets are now being applied to study electron driven processes in atmospheric phenomena [P. Thorn, L. Campbell, and M. Brunger, PMC Physics B 2, 1 (2009)] and in modeling charged particle tracks in matter [A. Munoz, F. Blanco, G. Garcia, P. A. Thorn, M. J. Brunger, J. P. Sullivan, and S. J. Buckman, Int. J. Mass Spectrom. 277, 175 (2008)].

  10. Prediction of clay content from water vapour sorption isotherms considering hysteresis and soil organic matter content

    DEFF Research Database (Denmark)

    Arthur, E.; Tuller, M.; Møldrup, Per

    2015-01-01

    Soil texture, in particular the clay fraction, governs numerous environmental, agricultural and engineering soil processes. Traditional measurement methods for clay content are laborious and impractical for large-scale soil surveys. Consequently, clay prediction models that are based on water...... within a RH range from 3 to 93%. The clay contents, which ranged between 1 and 56%, were measured with a combination of sieving and sedimentation methods. Two regression models were developed for both adsorption and desorption at 10 RH levels (5, 10, 20, 30, 40, 50, 60, 70, 80 and 90%). While the first...

  11. Derivation of water vapour absorption cross-sections in the red region

    Science.gov (United States)

    Lal, M.; Chakrabarty, D. K.

    1994-01-01

    Absorption spectrum in 436 to 448 nm wavelength region gives NO2 and O3 column densities. This spectrum can also give H2O column density. The spectrum in the range of 655 to 667 nm contains absorption due to NO3 and H2O. Combining the absorption spectra in the wavelength ranges of 436 to 448 and 655 to 667 nm, water vapor absorption cross-sections in this range comes out to be of the order of 2.0 x 10(exp -24) cm(exp -2).

  12. Application of remote sensing techniques to study aerosol water vapour uptake in a real atmosphere

    Science.gov (United States)

    Fernández, A. J.; Molero, F.; Becerril-Valle, M.; Coz, E.; Salvador, P.; Artíñano, B.; Pujadas, M.

    2018-04-01

    In this work, a study of several observations of aerosol water uptake in a real (non-controlled) atmosphere, registered by remote sensing techniques, are presented. In particular, three events were identified within the Atmospheric Boundary Layer (ABL) and other two events were detected in the free troposphere (beyond the top of the ABL). Then, aerosol optical properties were measured at different relative humidity (RH) conditions by means of a multi-wavelength (MW) Raman lidar located at CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Research Centre for Energy, Environment and Technology) facilities in Madrid (Spain). Additionally, aerosol optical and microphysical properties provided by automatic sun and sky scanning spectral radiometers (CIMEL CE-318) and a meteorological analysis complement the study. However, a detailed analysis only could be carried out for the cases observed within the ABL since well-mixed atmospheric layers are required to properly characterize these processes. This characterization of aerosol water uptake is based on the curve described by the backscatter coefficient at 532 nm as a function of RH which allows deriving the enhancement factor. Thus, the Hänel parameterization is utilized, and the results obtained are in the range of values reported in previous studies, which shows the suitability of this approach to study such hygroscopic processes. Furthermore, the anti-correlated pattern observed on backscatter-related Ångström exponent (532/355 nm) and RH indicates plausible signs of aerosol hygroscopic growth. According to the meteorological analysis performed, we attribute such hygroscopic behaviour to marine aerosols which are advected from the Atlantic Ocean to the low troposphere in Madrid. We have also observed an interesting response of aerosols to RH at certain levels which it is suggested to be due to a hysteresis process. The events registered in the free troposphere, which deal with volcano

  13. Range-energy relations and stopping power of water, water vapour and tissue equivalent liquid for α particles over the energy range 0.5 to 8 MeV

    International Nuclear Information System (INIS)

    Palmer, R.B.J.; Akhavan-Rezayat, Ahmad

    1978-01-01

    Experimental range-energy relations are presented for alpha particles in water, water vapour and tissue equivalent liquid at energies up to 8 MeV. From these relations differential stopping powers are derived at 0.25 MeV energy intervals. Consideration is given to sources of error in the range-energy measurements and to the uncertainties that these will introduce into the stopping power values. The ratio of the differential stopping power of muscle equivalent liquid to that of water over the energy range 0.5 to 7.5 MeV is discussed in relation to the specific gravity and chemical composition of the muscle equivalent liquid. Theoretical molecular stopping power calculations based upon the Bethe formula are also presented for water. The effect of phase upon the stopping power of water is discussed. The molecular stopping power of water vapour is shown to be significantly higher than that of water for energies below 1.25 MeV and above 2.5 MeV, the ratio of the two stopping powers rising to 1.39 at 0.5 MeV and to 1.13 at 7.0 MeV. Stopping power measurements for other liquids and vapours are compared with the results for water and water vapour and some are observed to have stopping power ratios in the vapour and liquid phases which vary with energy in a similar way to water. It is suggested that there may be several factors contributing to the increased stopping power of liquids. The need for further experimental results on a wider range of liquids is stressed

  14. Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

    KAUST Repository

    Li, Z. W.; Xu, Wenbin; Feng, G. C.; Hu, J.; Wang, C. C.; Ding, X. L.; Zhu, J. J.

    2012-01-01

    The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

  15. Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

    KAUST Repository

    Li, Z. W.

    2012-05-01

    The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

  16. Measuring variations of δ18O and δ2H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

    Directory of Open Access Journals (Sweden)

    S. Pfahl

    2012-07-01

    Full Text Available Variations of stable water isotopes in water vapour have become measurable at a measurement frequency of about 1 Hz in recent years using novel laser spectroscopic techniques. This enables us to perform continuous measurements for process-based investigations of the atmospheric water cycle at the time scales relevant for synoptic and mesoscale meteorology. An important prerequisite for the interpretation of data from automated field measurements lasting for several weeks or months is a detailed knowledge about instrument properties and the sources of measurement uncertainty. We present here a comprehensive characterisation and comparison study of two commercial laser spectroscopic systems based on cavity ring-down spectroscopy (Picarro and off-axis integrated cavity output spectroscopy (Los Gatos Research. The uncertainty components of the measurements were first assessed in laboratory experiments, focussing on the effects of (i water vapour mixing ratio, (ii measurement stability, (iii uncertainties due to calibration and (iv response times of the isotope measurements due to adsorption-desorption processes on the tubing and measurement cavity walls. Based on the experience from our laboratory experiments, we set up a one-week field campaign for comparing measurements of the ambient isotope signals from the two laser spectroscopic systems. The optimal calibration strategy determined for both instruments was applied as well as the correction functions for water vapour mixing ratio effects. The root mean square difference between the isotope signals from the two instruments during the field deployment was 2.3‰ for δ2H, 0.5‰ for δ18O and 3.1‰ for deuterium excess. These uncertainty estimates from field measurements compare well to those found in the laboratory experiments. The present quality of measurements from laser spectroscopic instruments combined with a calibration system opens new possibilities for investigating the atmospheric

  17. REMOVAL OF ARSENIC FROM DRINKING WATER SUPPLIES BY IRON REMOVAL PROCESS

    Science.gov (United States)

    This design manual is an in-depth presentation of the steps required to design and operate a water treatment plant for removal of arsenic in the As (V) form from drinking water using an iron removal process. The manual also discusses the capital and operating costs including many...

  18. Response of water vapour D-excess to land-atmosphere interactions in a semi-arid environment

    KAUST Repository

    Parkes, Stephen; McCabe, Matthew; Griffiths, Alan D.; Wang, Lixin; Chambers, Scott; Ershadi, Ali; Williams, Alastair G; Strauss, Josiah; Element, Adrian

    2016-01-01

    nocturnal inversion layer caused a lowering of dv values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate dET can generally be expected to show

  19. Methods of removing uranium from drinking water. 1. A literature survey. 2. Present municipal water treatment and potential removal methods

    International Nuclear Information System (INIS)

    Drury, J.S.; Michelson, D.; Ensminger, J.T.; Lee, S.Y.; White, S.K.

    1982-12-01

    Literature was searched for methods of removing uranium from drinking water. U.S. manufacturers and users of water-treatment equipment and products were also contacted regarding methods of removing uranium from potable water. Based on the results of these surveys, it was recommended that untreated, partially treated, and finished water samples from municipal water-treatment facilities be analyzed to determine the extent of removal of uranium by presently used procedures, and that additional laboratory studies be performed to determine what changes are needed to maximize the effectiveness of treatments that are already in use in existing water-treatment plants

  20. Numerical implementation and oceanographic application of the thermodynamic potentials of liquid water, water vapour, ice, seawater and humid air – Part 1: Background and equations

    Directory of Open Access Journals (Sweden)

    R. Feistel

    2010-07-01

    Full Text Available A new seawater standard referred to as the International Thermodynamic Equation of Seawater 2010 (TEOS-10 was adopted in June 2009 by UNESCO/IOC on its 25th General Assembly in Paris, as recommended by the SCOR/IAPSO Working Group 127 (WG127 on Thermodynamics and Equation of State of Seawater. To support the adoption process, WG127 has developed a comprehensive source code library for the thermodynamic properties of liquid water, water vapour, ice, seawater and humid air, referred to as the Sea-Ice-Air (SIA library. Here we present the background information and equations required for the determination of the properties of single phases and components as well as of phase transitions and composite systems as implemented in the library. All results are based on rigorous mathematical methods applied to the Primary Standards of the constituents, formulated as empirical thermodynamic potential functions and, except for humid air, endorsed as Releases of the International Association for the Properties of Water and Steam (IAPWS. Details of the implementation in the TEOS-10 SIA library are given in a companion paper.

  1. Arsenic removal in drinking water by reverse osmosis

    OpenAIRE

    Ahmad, Md. Fayej

    2012-01-01

    Arsenic is widely distributed in nature in the air, water and soil. Acute and chronic arsenic exposure by drinking water has been reported in many countries, especially Argentina, Bangladesh, India, Mexico, Mongolia, Thailand and Taiwan. There are many techniques used to remove arsenic from drinking water. Among them reverse osmosis is widely used. Therefore the purpose of this study is to find the conditions favorable for removal of arsenic from drinking water by using reverse osmosis ...

  2. Virus removal efficiency of Cambodian ceramic pot water purifiers.

    Science.gov (United States)

    Salsali, Hamidreza; McBean, Edward; Brunsting, Joseph

    2011-06-01

    Virus removal efficiency is described for three types of silver-impregnated, ceramic water filters (CWFs) produced in Cambodia. The tests were completed using freshly scrubbed filters and de-ionized (DI) water as an evaluation of the removal efficiency of the virus in isolation with no other interacting water quality variables. Removal efficiencies between 0.21 and 0.45 log are evidenced, which is significantly lower than results obtained in testing of similar filters by other investigators utilizing surface or rain water and a less frequent cleaning regime. Other experiments generally found virus removal efficiencies greater than 1.0 log. This difference may be because of the association of viruses with suspended solids, and subsequent removal of these solids during filtration. Variability in virus removal efficiencies between pots of the same manufacturer, and observed flow rates outside the manufacturer's specifications, suggest tighter quality control and consistency may be needed during production.

  3. Turbidity and microbes removal from water using an electrochemical filter

    International Nuclear Information System (INIS)

    Venkateswaran, G.; Gokhale, B.K.; Belapurkar, A.D.; Kumbhar, A.G.; Balaji, V.

    2004-01-01

    An in-house designed and fabricated Electrochemical fibrous graphite filter (ECF) was used to remove turbidity and microbes. The filter was found to be effective in removing sub micron size indium turbidity from RAPS-1 moderator water, iron turbidity from Active Process Cooling Water (APCW) of Kaiga Generating Station and microbial reduction from process cooling water RAPS-2. Unlike conventional turbidity removal by addition of coagulants and biocide chemical additions for purification, ECF is a clean way to remove the turbidity without contaminating the system and is best suited for close loop systems

  4. Water removal from a dry barrier cover system

    International Nuclear Information System (INIS)

    Stormont, J.C.; Ankeny, M.D.; Tansey, M.K.

    1994-01-01

    The results of the numerical simulations reveal that horizontal air flow through the coarse with reasonable pressure gradients can remove large quantities of water from the cover system. Initially, the water removal from the cover system is dominated by the evaporation and advection of water vapor out of the coarse layer. Once the coarse layer is dry, removal of water by evaporation near the fine/coarse layer interface reduces the local water content and water potential, and water moves toward the fine-coarse layer interface and becomes available for evaporation. This result is important in that it suggests the fine layer water content may be moderated by air flow in the coarse layer. Incorporating diffusion of water vapor from the fine layer into the coarse layer substantially increases the water movement out of the fine layer

  5. Studies in uptake and turnover of tritiated water vapour (HTO) by vegetables. Untersuchungen zur Aufnahme und zum Umsatz von tritiiertem Wasserdampf (HTO) in Gemuesepflanzen

    Energy Technology Data Exchange (ETDEWEB)

    Roller, M.

    1989-02-01

    The aerial parts of vegetables were exposed to tritiated water vapour for up to three days in a plant growth chamber. The species used were Raphanus sativus L., Phaseolus vulgaris K. and Daucus carota L. (red radish, bean and carrot). The increase of specific activity of tissue free water as collected by freeze drying which was observed in the aerial parts of plants is explained by direct uptake of tritiated water vapour by the exposed part of the plant. It shows different characteristics for the several organs. No translocation of water from the laminae into other parts of the plant was observed. After combustion of dry matter tritium activity was detectable in the oxidation water for all parts of the plants. Kinetics of the specific activity of organically bound tritium in leaves can be described by a single curve. The lower - steep - part of the curve is increasing approximately with the uptake rate of HTO; this is explained by reversible binding of tritium by isotopic exchange reactions. The upper - flat - part of the curve represents tritium bound by light dependent reducing reactions of photosynthesis; it is increasing with a rate similar to the growth rate of leaves. (orig./KG).

  6. Removal of trace metal contaminants from potable water by electrocoagulation

    OpenAIRE

    Heffron, Joe; Marhefke, Matt; Mayer, Brooke K.

    2016-01-01

    This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more...

  7. Removal of trace metal contaminants from potable water by electrocoagulation

    Science.gov (United States)

    Heffron, Joe; Marhefke, Matt; Mayer, Brooke K.

    2016-06-01

    This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency.

  8. Validation of GOME-2/MetOp-A total water vapour column using reference radiosonde data from GRUAN network

    Science.gov (United States)

    Antón, M.; Loyola, D.; Román, R.; Vömel, H.

    2014-09-01

    The main goal of this article is to validate the total water vapour column (TWVC) measured by the Global Ozone Monitoring Experiment-2 (GOME-2) satellite sensor and generated using the GOME Data Processor (GDP) retrieval algorithm developed by the German Aerospace Center (DLR). For this purpose, spatially and temporally collocated TWVC data from highly accurate sounding measurements for the period January 2009-May 2014 at six sites are used. These balloon-borne data are provided by GCOS Reference Upper-Air Network (GRUAN). The correlation between GOME-2 and sounding TWVC data is reasonably good (determination coefficient (R2) of 0.89) when all available radiosondes (1400) are employed in the inter-comparison. When cloud-free cases (544) are selected by means of the satellite cloud fraction (CF), the correlation exhibits a remarkable improvement (R2 ~ 0.95). Nevertheless, analyzing the six datasets together, the relative differences between GOME-2 and GRUAN data shows mean values (in absolute term) of 19% for all-sky conditions and 14% for cloud-free cases, which evidences a notable bias in the satellite TWVC data against the reference balloon-borne measurements. The satellite-sounding TWVC differences show a strong solar zenith angle (SZA) dependence for values above 50° with a stable behaviour for values below this zenith angle. The smallest relative differences found in the inter-comparison (between -5 and +3%) are achieved for those cloud-free cases with SZA below 50°. Furthermore, the detailed analysis of the influence of cloud properties (CF, cloud top albedo (CTA) and cloud top pressure (CTP)) on the satellite-sounding differences reveals, as expected, a large effect of clouds in the GOME-2 TWVC data. For instance, the relative differences exhibit a large negative dependence on CTA, varying from +5 to -20% when CTA rises from 0.3 to 0.9. Finally, the satellite-sounding differences also show a negative dependence on the reference TWVC values, changing from

  9. PES-Kaolin Mixed Matrix Membranes for Arsenic Removal from Water.

    Science.gov (United States)

    Marino, Tiziana; Russo, Francesca; Rezzouk, Lina; Bouzid, Abderrazak; Figoli, Alberto

    2017-09-30

    The aim of this work was the fabrication and the characterization of mixed matrix membranes (MMMs) for arsenic (As) removal from water. Membrane separation was combined with an adsorption process by incorporating the kaolin (KT2) Algerian natural clay in polymeric membranes. The effects of casting solution composition was explored using different amounts of polyethersufone (PES) as a polymer, polyvinyl-pyrrolidone (PVP K17) and polyethylene glycol (PEG 200) as pore former agents, N -methyl pyrrolidone (NMP) as a solvent, and kaolin. Membranes were prepared by coupling Non-solvent Induced Phase Separation and Vapour Induced Phase Separation (NIPS and VIPS, respectively). The influence of the exposure time to controlled humid air and temperature was also investigated. The MMMs obtained were characterized in terms of morphology, pore size, porosity, thickness, contact angle and pure water permeability. Adsorption membrane-based tests were carried out in order to assess the applicability of the membranes produced for As removal from contaminated water. Among the investigated kaolin concentrations (ranging from 0 wt % to 5 wt %), a content of 1.25 wt % led to the MMM with the most promising performance.

  10. The effectiveness of conventional water treatment in removing ...

    African Journals Online (AJOL)

    Algal blooms are a global problem due to various negative effects that can compromise water quality, such as the production of metabolites that are responsible for odour, colour, taste and toxins. In drinking water supplies algae can reduce the aesthetics of potable water when not readily removed by conventional water ...

  11. Studies of the kinetics and mechanism of the oxidation of uranium by dry and moist air. A model for determining the oxidation rate over a wide range of temperatures and water vapour pressures

    Energy Technology Data Exchange (ETDEWEB)

    McGillivray, G.W. (Atomic Weapons Establishment, Aldermaston, Reading (United Kingdom)); Geeson, D.A. (Atomic Weapons Establishment, Aldermaston, Reading (United Kingdom)); Greenwood, R.C. (Atomic Weapons Establishment, Aldermaston, Reading (United Kingdom))

    1994-01-01

    The rate of oxidation of uranium metal by moist air has been measured at temperatures from 115 to 350 C and water vapour pressures from 0 to 47 kPa (350 Torr). From this and from previously reported data, a model has been developed which allows the rate of uranium oxidation to be calculated at any particular combination of temperature and water vapour pressure of interest, in the range 0-350 C and 0-101.3 kPa (760 Torr). The model is based on the assumption that the surface concentration of water determines the rate of reaction and that the adsorption of water onto the oxide follows a Langmuir type isotherm. Theoretical plots of rate as a function of water vapour pressure and Arrhenius plots derived from the model have been shown to be in good agreement with experimental data. The model assumes separate contributions to the overall observed rate from oxygen and water vapour. Surface studies have been carried out using SIMS (secondary ion mass spectrometry). Depth profiling of the oxide produced by isotopically labelled reagents ([sup 18]O[sub 2] and H[sup 18][sub 2]O), has shown that oxygen from both reactants is incorporated into the oxide layer in the ratio predicted by the kinetic model. This supports a mechanism in which oxygen and water vapour produce separate diffusing species (possibly O[sup 2-] and OH[sup -]). (orig.)

  12. Studies of the kinetics and mechanism of the oxidation of uranium by dry and moist air A model for determining the oxidation rate over a wide range of temperatures and water vapour pressures

    Science.gov (United States)

    McGillivray, G. W.; Geeson, D. A.; Greenwood, R. C.

    1994-01-01

    The rate of oxidation of uranium metal by moist air has been measured at temperatures from 115 to 350°C and water vapour pressures from 0 to 47 kPa (350 Torr). From this and from previously reported data, a model has been developed which allows the rate of uranium oxidation to be calculated at any particular combination of temperature and water vapour pressure of interest, in the range 0-350°C and 0-101.3 kPa (760 Torr). The model is based on the assumption that the surface concentration of water determines the rate of reaction and that the adsorption of water onto the oxide follows a Langmuir type isotherm. Theoretical plots of rate as a function of water vapour pressure and Arrhenius plots derived from the model have been shown to be in good agreement with experimental data. The model assumes separate contributions to the overall observed rate from oxygen and water vapour. Surface studies have been carried out using SIMS (secondary ion mass spectrometry). Depth profiling of the oxide produced by isotopically labelled reagents ( 18O 2 and H 218O), has shown that oxygen from both reactants is incorporated into the oxide layer in the ratio predicted by the kinetic model. This supports a mechanism in which oxygen and water vapour produce separate diffusing species (possibly O 2- and OH -).

  13. Water vapour inter-comparison effort in the framework of the hydrological cycle in the mediterranean experiment - special observation period (hymex-sop1)

    Science.gov (United States)

    Summa, Donato; Di Girolamo, Paolo; Flamant, Cyrille; De Rosa, Benedetto; Cacciani, Marco; Stelitano, Dario

    2018-04-01

    Accurate measurements of the vertical profiles of water vapour are of paramount importance for most key areas of atmospheric sciences. A comprehensive inter-comparison between different remote sensing and in-situ sensors has been carried out in the frame work of the first Special Observing Period of the Hydrological cycle in the Mediterranean Experiment for the purpose of obtaining accurate error estimates for these sensors. The inter-comparison involves a ground-based Raman lidar (BASIL), an airborne DIAL (LEANDRE2), a microwave radiometer, radiosondes and aircraft in-situ sensors.

  14. Water vapour inter-comparison effort in the framework of the hydrological cycle in the mediterranean experiment – special observation period (hymex-sop1

    Directory of Open Access Journals (Sweden)

    Summa Donato

    2018-01-01

    Full Text Available Accurate measurements of the vertical profiles of water vapour are of paramount importance for most key areas of atmospheric sciences. A comprehensive inter-comparison between different remote sensing and in-situ sensors has been carried out in the frame work of the first Special Observing Period of the Hydrological cycle in the Mediterranean Experiment for the purpose of obtaining accurate error estimates for these sensors. The inter-comparison involves a ground-based Raman lidar (BASIL, an airborne DIAL (LEANDRE2, a microwave radiometer, radiosondes and aircraft in-situ sensors.

  15. The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes.

    Science.gov (United States)

    Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

    2016-05-01

    Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below -1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for improved productivity under water-limiting conditions

  16. Analysis of microplastics and their removal from water

    OpenAIRE

    Oladejo, Abiola

    2017-01-01

    Removal of microplastics from water was studied using extraction with oil. The aim of the thesis was to remove microplastics from water using an organic medium, and to analyse the amount of microplastics in the media involved. The separation of different microplastic types was done by conducting experiments in the laboratory. The microplastics were made by grinding and sieving plastics with a grinding machine before adding them to water and oil, which serves as the organic medium. Tw...

  17. Sulphur dioxide removal by turbulent transfer over grass, snow, and water surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Whelpdale, D M; Shaw, R W

    1974-01-01

    Vertical gradients of sulphur dioxide concentration have been measured over grass, snow, and water surfaces in order to assess the importance of these surfaces as SO/sub 2/ sinks. Concentrations were usually found to be lower near the surface indicating that removal occurs there. Vertical concentration gradients, normalized with repect to the concentration at 8 m, were generally greatest over water and least over snow, independent of meteorological conditions, suggesting that a water surface is the strongest SO/sub 2/ sink, with grass next, and snow weakest. The turbulent transfer of SO/sub 2/ to the interface is discussed in relation to stability of the lower atmosphere and physical and chemical properties of the surfaces. Using a bulk aerodynamic transfer approach similar to that for water vapour, values of SO/sub 2/ flux averaged over periods of from one to several hours were found to be of the order of 1 microgram/M/sup 2//S to the water and grass surfaces, and an order of magnitude smaller to the snow surface. Deposition velocities were found to be of the order of 1 cm/s.

  18. TURBIDITY REMOVAL FROM SURFACE WATER USING ...

    African Journals Online (AJOL)

    User

    2016-06-01

    Jun 1, 2016 ... Plant-based coagulants are potential alternatives to chemical coagulants used in drinking water treatment. ... Conventional water treatment systems involve the use of synthetic ..... Thesis, Royal Institute of Technology (KTH),.

  19. The Effect of Water Chemistry on the Removal of Arsenic from Drinking Water During Iron Removal Treatment

    Science.gov (United States)

    This research investigates the effects of water chemistry, oxidant type and concentration on the removal of iron and arsenic from drinking water. The research will be conducted using one of the National Risk Management Research Laboratory’s Water Supply and Water Resources Divisi...

  20. TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

    Directory of Open Access Journals (Sweden)

    RAISA NASTAS

    2012-03-01

    Full Text Available Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the type of impregnated heteroatom (N, O, or metals (Fe, Cu, Ni, on removal of hydrogen sulfide species and nitrite ions have been researched. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous ground waters. Comparative analysis of carbonaceous adsorbents reveals the importance of surface chemistry for oxidation of nitrite ions.

  1. Present municipal water treatment and potential removal methods

    International Nuclear Information System (INIS)

    Lee, S.Y.; White, S.K.; Bondietti, E.A.

    1982-01-01

    Uranium analyses of raw water, intermediate stage, and treated water samples from 20 municipal water treatment plants indicated that the present treatment practices were not effective in removing uranium from raw waters when the influent concentration was in the range of 0.1 to 16 μg/L uranium. Laboratory batch tests revealed that the water softening and coagulant chemicals commonly used were able to remove more than 90% of the dissolved uranium ( < 100 μg/L) in waters if an optimum pH and dosage were provided. Absorbents, titanium oxide and activated charcoal, were also effective in uranium removal under specific conditions. Strong base anion exchange resin was the most efficient uranium adsorbent, and an anion exchange column is a recommended option for the treatment of private well waters containing uranium at higher than desirable levels

  2. Heavy water handbook. Evaluation of available thermophysical properties of heavy water (D2O) liquid and vapour

    International Nuclear Information System (INIS)

    Bukovsky, J.; Haack, K.; Wiig, P.

    1993-01-01

    Numerous publications on the thermophysical data of heavy water (D 2 O) have been published since D 2 O became commercially available in the 1930's. Some of these data are in mutual disagreement. This has led to confusion among the scientifical and technical staffs who needed the information on the D 2 O thermophysical data. Correct thermophysical data must be consistent, i.e. their mutual relations must be in accordance to the fundamental thermophysical laws. The work behind this publication has been focussed at collecting all avalilable D 2 O data and checking the data mutually by means of these fundamental thermophysical criteria. Depending on the various production methods, the oxygen content of the D 2 O is enriched more or less in the heavier oxygen isotopes 17 O and 18 O. This, together with the amount of impurities and dissolved gases in the D 2 O samples of the various references, might - to some extent - explain the discrepancies between the data sources. Only a few references contain information on these subjects. The D 2 O data sets which were found to be the most reliable are presented in chapter 9, in tables as well as in diagrams, together with the corresponding H 2 O data for comparison. The diagrams are commented for reliability where it was found necessary. Furthermore, the publication contains short descriptions on the heavy water sources, availability, production processes, economy, material and energy demands for production. A comprehensive list of references is enclosed. (author)

  3. Heavy water handbook. Evaluation of presently available thermophysical properties of heavy water (D2O) liquid and vapour

    International Nuclear Information System (INIS)

    Bukovsky, J.; Haack, K.

    1994-08-01

    Many publication on the thermophysical properties of heavy water (D 2 O) have appeared since D 2 O became commercially available in the 1930's. Some for the data contradict one another and this has led to confusion when information is needed on D 2 O thermophysical data. Correct thermophysical data must be consistent, i.e. their mutual dependence must be consistent with fundamental thermophysical laws. The work behind this publication has focused on collecting all available D 2 O data and checking them against these fundamental thermophysical criteria. Depending on the various production methods for D 2 O, its oxygen content is enriched more or less by the heavier oxygen isotopes 17 O and 18 O. This, together with the amount of impurities and dissolved gases in the D 2 O samples of the various references, might - to some extent - explain the discrepancies found between the data. Only a few references contain information on these subjects. The D 2 O data sets found to be the most reliable are presented in Chapter 9, in tables as well as in diagrams, together with the corresponding H 2 O data for comparison. Comments on the reliability of the diagrams are given where necessary. Furthermore, short descriptions are given of heavy water sources, availability, production processes, economy, material and energy requirements for the production process. Finally a comprehensive list of references and an author index are included. (au)

  4. Factors affecting radon removal from Rn-222 enriched water

    International Nuclear Information System (INIS)

    Abulfaraj, W.H.; Mamoon, A.

    1994-01-01

    Continued use of potable well water that has elevated levels of Rn-222 is harmful to human health. activated carbon, aeration and heating can remove radon from treated water. Water artificially enriched with Rn-222 using a pitchblende source was studied in a laboratory scale model under controlled conditions. (author), 3 figs., 3 refs

  5. Characterization of simultaneous heat and mass transfer phenomena for water vapour condensation on a solid surface in an abiotic environment--application to bioprocesses.

    Science.gov (United States)

    Tiwari, Akhilesh; Kondjoyan, Alain; Fontaine, Jean-Pierre

    2012-07-01

    The phenomenon of heat and mass transfer by condensation of water vapour from humid air involves several key concepts in aerobic bioreactors. The high performance of bioreactors results from optimised interactions between biological processes and multiphase heat and mass transfer. Indeed in various processes such as submerged fermenters and solid-state fermenters, gas/liquid transfer need to be well controlled, as it is involved at the microorganism interface and for the control of the global process. For the theoretical prediction of such phenomena, mathematical models require heat and mass transfer coefficients. To date, very few data have been validated concerning mass transfer coefficients from humid air inflows relevant to those bioprocesses. Our study focussed on the condensation process of water vapour and developed an experimental set-up and protocol to study the velocity profiles and the mass flux on a small size horizontal flat plate in controlled environmental conditions. A closed circuit wind tunnel facility was used to control the temperature, hygrometry and hydrodynamics of the flow. The temperature of the active surface was controlled and kept isothermal below the dew point to induce condensation, by the use of thermoelectricity. The experiments were performed at ambient temperature for a relative humidity between 35-65% and for a velocity of 1.0 ms⁻¹. The obtained data are analysed and compared to available theoretical calculations on condensation mass flux.

  6. Impact of water vapour and carbon dioxide on surface composition of C{sub 3}A polymorphs studied by X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dubina, E.; Plank, J. [Technische Universität München, Lehrstuhl für Bauchemie, Lichtenbergstr. 4, 85747 Garching bei München (Germany); Black, L., E-mail: l.black@leeds.ac.uk [Institute for Resilient Infrastructure, School of Civil Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2015-07-15

    The surface specific analytical method, X-ray photoelectron spectroscopy (XPS), has been used to study the effects of water vapour and CO{sub 2} on the cubic and orthorhombic polymorphs of C{sub 3}A. Significant differences between the two polymorphs were observed in the XPS spectra. Upon exposure to water vapour, both polymorphs produced C{sub 4}AH{sub 13} on their surfaces. Additionally, the sodium-doped o-C{sub 3}A developed NaOH and traces of C{sub 3}AH{sub 6} on its surface. Subsequent carbonation yielded mono carboaluminate on both polymorphs. Large amounts of Na{sub 2}CO{sub 3} also formed on the surface of o-C{sub 3}A as a result of carbonation of NaOH. Furthermore, the extent of carbonation was much more pronounced for o-C{sub 3}A{sub o} than for c-C{sub 3}A.

  7. The water vapour self-continuum absorption in the infrared atmospheric windows: new laser measurements near 3.3 and 2.0 µm

    Directory of Open Access Journals (Sweden)

    L. Lechevallier

    2018-04-01

    Full Text Available The amplitude, the temperature dependence, and the physical origin of the water vapour absorption continuum are a long-standing issue in molecular spectroscopy with direct impact in atmospheric and planetary sciences. In recent years, we have determined the self-continuum absorption of water vapour at different spectral points of the atmospheric windows at 4.0, 2.1, 1.6, and 1.25 µm, by highly sensitive cavity-enhanced laser techniques. These accurate experimental constraints have been used to adjust the last version (3.2 of the semi-empirical MT_CKD model (Mlawer-Tobin_Clough-Kneizys-Davies, which is widely incorporated in atmospheric radiative-transfer codes. In the present work, the self-continuum cross-sections, CS, are newly determined at 3.3 µm (3007 cm−1 and 2.0 µm (5000 cm−1 by optical-feedback-cavity enhanced absorption spectroscopy (OFCEAS and cavity ring-down spectroscopy (CRDS, respectively. These new data allow extending the spectral coverage of the 4.0 and 2.1 µm windows, respectively, and testing the recently released 3.2 version of the MT_CKD continuum. By considering high temperature literature data together with our data, the temperature dependence of the self-continuum is also obtained.

  8. The water vapour self-continuum absorption in the infrared atmospheric windows: new laser measurements near 3.3 and 2.0 µm

    Science.gov (United States)

    Lechevallier, Loic; Vasilchenko, Semen; Grilli, Roberto; Mondelain, Didier; Romanini, Daniele; Campargue, Alain

    2018-04-01

    The amplitude, the temperature dependence, and the physical origin of the water vapour absorption continuum are a long-standing issue in molecular spectroscopy with direct impact in atmospheric and planetary sciences. In recent years, we have determined the self-continuum absorption of water vapour at different spectral points of the atmospheric windows at 4.0, 2.1, 1.6, and 1.25 µm, by highly sensitive cavity-enhanced laser techniques. These accurate experimental constraints have been used to adjust the last version (3.2) of the semi-empirical MT_CKD model (Mlawer-Tobin_Clough-Kneizys-Davies), which is widely incorporated in atmospheric radiative-transfer codes. In the present work, the self-continuum cross-sections, CS, are newly determined at 3.3 µm (3007 cm-1) and 2.0 µm (5000 cm-1) by optical-feedback-cavity enhanced absorption spectroscopy (OFCEAS) and cavity ring-down spectroscopy (CRDS), respectively. These new data allow extending the spectral coverage of the 4.0 and 2.1 µm windows, respectively, and testing the recently released 3.2 version of the MT_CKD continuum. By considering high temperature literature data together with our data, the temperature dependence of the self-continuum is also obtained.

  9. Treatment technology for removing radon from small community water supplies

    International Nuclear Information System (INIS)

    Kinner, N.E.; Quern, P.A.; Schell, G.S.; Lessard, C.E.; Clement, J.A.

    1989-01-01

    Radon contamination of drinking water primarily affects individual homeowners and small communities using ground-water supplies. Presently, three types of treatment processes have been used to remove radon: granular activated carbon adsorption (GAC), diffused-bubble aeration, and packed-tower aeration. In order to obtain data on these treatment alternatives for small communities water supplies, a field evaluation study was conducted on these three processes as well as on several modifications to aeration of water in storage tanks considered to be low cost/low technology alternatives. The paper presents the results of these field studies conducted at a small mobile home park in rural New Hampshire. The conclusion of the study was that the selection of the appropriate treatment system to remove radon from drinking water depends primarily upon: (1) precent removal of process; (2) capital operating and maintenance costs; (3) safety (radiation); and (4) raw water quality (Fe, Mn, bacteria and organics)

  10. Trace-level mercury removal from surface water

    International Nuclear Information System (INIS)

    Klasson, K.T.; Bostick, D.T.

    1998-01-01

    Many sorbents have been developed for the removal of mercury and heavy metals from waters; however, most of the data published thus far do not address the removal of mercury to the target levels represented in this project. The application to which these sorbents are targeted for use is the removal of mercury from microgram-per-liter levels to low nanogram-per-liter levels. Sorbents with thiouronium, thiol, amine, sulfur, and proprietary functional groups were selected for these studies. Mercury was successfully removed from surface water via adsorption onto Ionac SR-4 and Mersorb resins to levels below the target goal of 12 ng/L in batch studies. A thiol-based resin performed the best, indicating that over 200,000 volumes of water could be treated with one volume of resin. The cost of the resin is approximately $0.24 per 1,000 gal of water

  11. Removal method of radium in mine water by filter sand

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Naganuma, Masaki

    2003-01-01

    Trace radium is contained in mine water from the old mine road in Ningyo-Toge Environmental Engineering Center, JNC. We observed that filter sand with hydrated manganese oxide adsorbed radium in the mine water safely for long time. The removal method of radium by filter sand cladding with hydrated manganese oxide was studied. The results showed that radium was removed continuously and last for a long time from mine water with sodium hypochlorite solution by passing through the filter sand cladding with hydrated manganese. Only sodium hypochlorite solution was used. When excess of it was added, residue chlorine was used as chlorine disinfection. Filter sand cladding with hydrated manganese on the market can remove radium in the mine water. The removal efficiency of radium is the same as the radium coprecipitation method added with barium chloride. The cost is much lower than the ordinary methods. Amount of waste decreased to about 1/20 of the coprecipitation method. (S.Y.)

  12. performance of water filters towards the removal of selected

    African Journals Online (AJOL)

    Morohani Merinyo

    sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% ... associated diseases in developing countries ... The main drinking water risks in developing ... Tanzania Demographic and Health Survey.

  13. Study of a micro-sublimation apparatus with removal of the vapours by pumping; application to the analysis of fluorinated products (1963)

    International Nuclear Information System (INIS)

    Delvalle, P.

    1963-01-01

    Micro-sublimation analysis presents definite advantages both from the qualitative and quantitative points of view. An automatic micro-sublimation analysis apparatus has been developed for the analysis of fluorinated products (ClF 3 , HF, UF 6 , etc.) but this is only one particular application of a method which has a far wider field of possible applications. We give first the most favorable conditions for the operation of such an apparatus. These conditions are the use of a detector which is linear and independent of the nature of the gas, the flow of the sublimed vapours in the conditions of molecular flow, and finally a reproducible and linear re-heating of the separating trap. The apparatus thus built has the advantage of yielding any analysis without prior calibration. It also makes possible the easy identification of an unknown product by the determination of its vapour pressure curve and its molecular weight. The analysis of fluorinated products with this apparatus has shown that the experimental results agree well with what is expected. (author) [fr

  14. Compositions and methods for removing arsenic in water

    Science.gov (United States)

    Gadgil, Ashok Jagannth [El Cerrito, CA

    2011-02-22

    Compositions and methods and for contaminants from water are provided. The compositions comprise ferric hydroxide and ferric oxyhydride coated substrates for use in removing the contaminant from the water. Contacting water bearing the contaminant with the substrates can substantially reduce contaminant levels therein. Methods of oxidizing the contaminants in water to facilitate their removal by the ferric hydroxide and ferric oxyhydride coated substrates are also provided. The contaminants include, but are not limited to, arsenic, selenium, uranium, lead, cadmium, nickel, copper, zinc, chromium and vanadium, their oxides and soluble salts thereof.

  15. Removal of Strontium from Drinking Water by Conventional ...

    Science.gov (United States)

    The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. There is very little data available on strontium removal from drinking water. As a result, there is an immediate need to perform treatment studies. The objective of this work is to evaluate the effectiveness of conventional and lime-soda ash softening treatments to remove strontium from surface and ground waters. Conventional drinking water treatment with aluminum and iron coagulants were able to achieve 12% and 5.9% strontium removal at best, while lime softening removed as much as 78% from natural strontium-containing ground water. Systematic fundamental experiments showed that strontium removal during the lime-soda ash softening was related to pH, calcium concentration and dissolved inorganic carbon concentration. Final strontium concentration was also directly associated with initial strontium concentration. Precipitated solids showed well-formed crystals or agglomerates of mixed solids, two polymorphs of calcium carbonate (vaterite and calcite), and strontianite, depending on initial water quality conditions. X-ray diffraction analysis suggested that strontium likely replaced calcium inside the crystal lattice and was likely mainly responsible for removal during lime softening. To inform the public.

  16. The other GHG : steps taken to reduce CO2 emissions may contribute to increased levels of water vapour in the atmosphere

    International Nuclear Information System (INIS)

    Collison, M.

    2008-01-01

    As a result of the Intergovernmental Panel on Climate Change (IPCC), the Canadian oil and gas industry and government are now in the midst of a massive overhaul of hydrocarbon energy use and carbon dioxide (CO 2 ) management. However, human-enhanced water evaporation (HEWE) may also be a significant contributor to global climate warming. Human-caused distortions of the hydrological cycle can cause multiple localized weather disturbances. There is currently a thousand times more water vapor being emitted than CO 2 , and this is contributing to increased rainfall levels around the world. Expansion of the agriculture and growth of industry has caused significant diversions and redistributions of water. Most of the water used is evaporated in the northern hemisphere. Climate modellers are needed to analyze the impacts of human-enhanced water evaporation local climates and weather. The main sources of water emissions are government-controlled energy projects and subsidized irrigation projects. Current levels of water vapour emissions are between 10 and 100 times the value of warming per tonne as CO 2 . Details of various research projects to use salt water as a fuel for vehicles was provided, as well as methods of improving the water-gas shift reaction method of hydrogen production. 2 figs

  17. A Raman lidar at La Reunion (20.8° S, 55.5° E for monitoring water vapour and cirrus distributions in the subtropical upper troposphere: preliminary analyses and description of a future system

    Directory of Open Access Journals (Sweden)

    C. Hoareau

    2012-06-01

    Full Text Available A ground-based Rayleigh lidar has provided continuous observations of tropospheric water vapour profiles and cirrus cloud using a preliminary Raman channels setup on an existing Rayleigh lidar above La Reunion over the period 2002–2005. With this instrument, we performed a first measurement campaign of 350 independent water vapour profiles. A statistical study of the distribution of water vapour profiles is presented and some investigations concerning the calibration are discussed. Analysis regarding the cirrus clouds is presented and a classification has been performed showing 3 distinct classes. Based on these results, the characteristics and the design of a future lidar system, to be implemented at the new Reunion Island altitude observatory (2200 m for long-term monitoring, is presented and numerical simulations of system performance have been realised to compare both instruments.

  18. Thermodynamics of the ternary systems: (water + glycine, L-alanine and L-serine + di-ammonium hydrogen citrate) from volumetric, compressibility, and (vapour + liquid) equilibria measurements

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Gholamireza, Afsaneh

    2011-01-01

    The apparent molar volumes and isentropic compressibility of glycine, L-alanine and L-serine in water and in aqueous solutions of (0.500 and 1.00) mol . kg -1 di-ammonium hydrogen citrate {(NH 4 ) 2 HCit} and those of (NH 4 ) 2 HCit in water have been obtained over the (288.15 to 313.15) K temperature range at 5 K intervals at atmospheric pressure from measurements of density and ultrasonic velocity. The apparent molar volume and isentropic compressibility values at infinite dilution of the investigated amino acids have been obtained and their variations with temperature and their transfer properties from water to aqueous solutions of (NH 4 ) 2 HCit have also been obtained. The results have been interpreted in terms of the hydration of the amino acids. In the second part of this work, water activity measurements by the isopiestic method have been carried out on the aqueous solutions of {glycine + (NH 4 ) 2 HCit}, {alanine + (NH 4 ) 2 HCit}, and {serine + (NH 4 ) 2 HCit} at T = 298.15 K at atmospheric pressure. From these measurements, values of vapour pressure, osmotic coefficient, activity coefficient and Gibbs free energy were obtained. The effect of the type of amino acids on the (vapour + liquid) equilibrium of the systems investigated has been studied. The experimental water activities have been correlated successfully with the segment-based local composition Wilson model. Furthermore, the thermodynamic behaviour of the ternary solutions investigated has been studied by using the semi-ideal hydration model and the linear concentration relations have been tested by comparing with the isopiestic measurements for the studied systems at T = 298.15 K.

  19. Thermodynamics of the ternary systems: (water + glycine, L-alanine and L-serine + di-ammonium hydrogen citrate) from volumetric, compressibility, and (vapour + liquid) equilibria measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat, E-mail: rahsadeghi@yahoo.co [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Gholamireza, Afsaneh [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2011-02-15

    The apparent molar volumes and isentropic compressibility of glycine, L-alanine and L-serine in water and in aqueous solutions of (0.500 and 1.00) mol . kg{sup -1} di-ammonium hydrogen citrate {l_brace}(NH{sub 4}){sub 2}HCit{r_brace} and those of (NH{sub 4}){sub 2}HCit in water have been obtained over the (288.15 to 313.15) K temperature range at 5 K intervals at atmospheric pressure from measurements of density and ultrasonic velocity. The apparent molar volume and isentropic compressibility values at infinite dilution of the investigated amino acids have been obtained and their variations with temperature and their transfer properties from water to aqueous solutions of (NH{sub 4}){sub 2}HCit have also been obtained. The results have been interpreted in terms of the hydration of the amino acids. In the second part of this work, water activity measurements by the isopiestic method have been carried out on the aqueous solutions of {l_brace}glycine + (NH{sub 4}){sub 2}HCit{r_brace}, {l_brace}alanine + (NH{sub 4}){sub 2}HCit{r_brace}, and {l_brace}serine + (NH{sub 4}){sub 2}HCit{r_brace} at T = 298.15 K at atmospheric pressure. From these measurements, values of vapour pressure, osmotic coefficient, activity coefficient and Gibbs free energy were obtained. The effect of the type of amino acids on the (vapour + liquid) equilibrium of the systems investigated has been studied. The experimental water activities have been correlated successfully with the segment-based local composition Wilson model. Furthermore, the thermodynamic behaviour of the ternary solutions investigated has been studied by using the semi-ideal hydration model and the linear concentration relations have been tested by comparing with the isopiestic measurements for the studied systems at T = 298.15 K.

  20. Removal of soluble toxic metals from water

    International Nuclear Information System (INIS)

    Buckley, L.P.; Vijayan, S.; McConeghy, G.J.; Maves, S.R.; Martin, J.F.

    1990-05-01

    The removal of selected, soluble toxic metals from aqueous solutions has been accomplished using a combination of chemical treatment and ultrafiltration. The process has been evaluated at the bench-scale and is undergoing pilot-scale testing. Removal efficiencies in excess of 95-99% have been realized. The test program at the bench-scale investigated the limitations and established the optimum range of operating parameters for the process, while the tests conducted with the pilot-scale process equipment are providing information on longer-term process efficiencies, effective processing rates, and fouling potential of the membranes. With the typically found average concentrations of the toxic metals in groundwaters at Superfund sites used as the feed solution, the process has decreased levels up to 100-fold or more. Experiments were also conducted with concentrated solutions to determine their release from silica-based matrices. The solidified wastes were subjected to EP Toxicity test procedures and met the criteria successfully. The final phase of the program involving a field demonstration at a uranium tailings site will be outlined

  1. Study on arsenic removal process from water

    Directory of Open Access Journals (Sweden)

    B Bayarmaa

    2014-09-01

    Full Text Available In this study a novel adsorbent, iron oxide, is used for As (V or As (III removal. Some ferric oxides have been reported to be effective for arsenic removal. Ferric oxides powder is a good adsorbent material since it’s has magnetic properties and a good adsorption capacity. The main purpose of this study has been focused on to study the relationship between adsorption capacity (ability, performance and the surface characteristics of the ferric oxide. Prepared sample’s capacity was evaluated. The value was 26.1-67.4 mg/g for As (V and 20.5-47.8 mg/g for As (III. pH dependence was evaluated and when pH increasing, adsorption capacity was decreased. The kinetic was evaluated and about 12 hours reached equilibrium and a capacity of 49 mg/g for As (V and 42 mg/g for As(III was gained. The kinetic constants for arsenic adsorption on the ferrihydrite adsorbent’s were fitted.DOI: http://dx.doi.org/10.5564/mjc.v12i0.172 Mongolian Journal of Chemistry Vol.12 2011: 53-55

  2. Materials removal by water jets with high relative velocity

    International Nuclear Information System (INIS)

    Schikorr, W.

    1986-01-01

    By way of introduction approaches to the systematic apprehension of the material removal by water jets up to 1000 bar are made. In drilling experiments the effects of jet dynamic are studied, using the controlled disintegration of the jet. Using model-layer-systems the removal of layers by the 'natural' disintegrating fluid-jet is examined. The mechanisms of material removal and the consequences on the praxis of cleaning are discussed. A concept to measure specially the effects of the dynamic jet components is developed. In conclusion aspects of progress in this methods of material removal are discussed. (orig.) [de

  3. Removal of some radionuclides from water by bioaccumulation

    International Nuclear Information System (INIS)

    Miskovic, D.; Conkic, L.; Dalmacija, B.; Gantar, M.

    1992-01-01

    First objective of this study was to investigate the application of biologically activated carbon (BAC) as well as its comparison to adsorption, with the aim of removing some radionuclides from water. The isotopes Cs 134 and Cs 137 were bioaccumulated by BAC up to 50%, while the I 131 isotope was only physicochemically adsorbed (about 40%). Also, the process of radionuclides (Cs 137 , Ce 139 , Co 57 , Co 60 ) fixation on blue-green algae (Nostoc sp.) was investigated. The kinetics of the removal of these radionuclides from water was recorded. It was found that after a contact period of about half an hour 40-70% of the activity was removed. (Author)

  4. Removal of oil products from fitters in water treatment plants

    International Nuclear Information System (INIS)

    Carlson, B.B.; Olander, M.A.; Arvin, E.

    1996-01-01

    Gasoline and oil spills cause aromatic hydrocarbon pollution of ground water. Benzene, toluene and naphtalene can be found in water wells. The purpose of the experiment was to investigate the filtering of water and biological degradation of aromatics on water treatment filters. These filters were proved to reduce benzene, toluene and naphtalene concentration from 5-12 μg/l to 0,3-0,6 μg/l (86-98 % removal). (EG)

  5. Effect of color removal agent on textiles waste water

    International Nuclear Information System (INIS)

    Khomsaton Abu Bakar; Selambakknu, Sarala; Jamaliah Shariff; Ting, Teo Ming; Khairul Zaman Dahlan

    2010-01-01

    The effect of color removal agent (CRA) on textile waste water has been studied. The aim of this work is to determine the optimum condition for CRA to react on the textile waste water and to see the effect of CRA on waste water with different Chemical Oxygen Demand. 8 ml CRA was used to treat 800 mls of sample with various COD ranging between 2500 mg/ l-500 mg/ l. The results showed that CRA totally remove the colour of textile waste water at pH ranging from 6 to 8. At an optimum condition CRA works efficiently on waste water with COD 2300 mg/ l for reduction of suspended solid and turbidity. It also observed, sludge accumulation was depended on COD concentration. Color removal curves for different initial COD concentration also obtained. (author)

  6. Escherichia Coli Removal from Water Using Electrophotocatalytic ...

    African Journals Online (AJOL)

    Michael Horsfall

    inactivation of bacterial microorganisms in areas with low ... disinfection of water contaminated with fecal indicators such as E. coli ... media, brain heart infusion, sodium chloride, sodium hydroxide ... furnace at temperature 105 and 320°C f0r 60 min. For 2- and .... charge of E. coli logarithmic growth phase might affect the ...

  7. Removal of gadolinium nitrate from heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.

    2000-03-22

    Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

  8. Removal of Pesticides From Water by Nanofiltration

    OpenAIRE

    RIUNGU, N J; HESAMPOUR, M; PIHLAJAMAKI, A; MANTTARI, M; home, P G; NDEGWA, G M

    2012-01-01

    Agricultural activities form the backborne of Kenyas economy. Inorder to control crop losses, pesticides are used and in the recent past, more of the pesticides have been used to increase production. However, the effect of pesticides on the environment is very complex as undesirable transfers occur continually among different environmental sections. This eventually leads to contamination of drinking water source especially for rivers and lakes located near active agriculture practices especia...

  9. The Liquid Vapour Interface

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1985-01-01

    In this short review we are concerned with the density variation across the liquid-vapour interface, i.e. from the bulk density of the liquid to the essentially zero density of the vapour phase. This density variation can in principle be determined from the deviation of the reflectivity from...

  10. Removal of phenol from water : a comparison of energization methods

    NARCIS (Netherlands)

    Grabowski, L.R.; Veldhuizen, van E.M.; Rutgers, W.R.

    2005-01-01

    Direct electrical energization methods for removal of persistent substances from water are under investigation in the framework of the ytriD-project. The emphasis of the first stage of the project is the energy efficiency. A comparison is made between a batch reactor with a thin layer of water and

  11. USE OF SYNTHETIC ZEOLITES FOR ARSENATE REMOVAL FROM POLLUTANT WATER

    Science.gov (United States)

    Arsenic is known to be a hazardous contaminant in drinking water that causes arsenical dermatitis and skin cancer. In the present work, the potential use of a variety of synthetic zeolites for removal of arsenic from water below the current and proposed EPA MCL has been examined...

  12. 40 CFR 1065.659 - Removed water correction.

    Science.gov (United States)

    2010-07-01

    ... water content according to paragraph (b)(1) of this section. (3) You may also use a nominal value of...) Use any of the techniques described in paragraph (b) of this section. (2) If the measurement comes.... (a) If you remove water upstream of a concentration measurement, x, or upstream of a flow measurement...

  13. Turbidity removal from surface water using Tamarindus indica crude ...

    African Journals Online (AJOL)

    Plant-based coagulants are potential alternatives to chemical coagulants used in drinking water treatment. This paper examined the turbidity removal efficiency of Tamarindus indica fruit crude pulp extract (CPE) towards evaluating a low-cost option for drinking-water treatment. Laboratory analysis was carried out on high ...

  14. Water Recycling removal using temperature-sensitive hydronen

    Energy Technology Data Exchange (ETDEWEB)

    Rana B. Gupta

    2002-10-30

    The overall objective of this project was to study the proposed Water Recycling/Removal Using Temperature-Sensitive Hydrogels. The main element of this technology is the design of a suitable hydrogel that can perform needed water separation for pulp and paper industry. The specific topics studied are to answer following questions: (a) Can water be removed using hydrogel from large molecules such as lignin? (b) Can the rate of separation be made faster? (c) What are the molecular interactions with hydrogel surface? (d) Can a hydrogel be designed for a high ionic strength and high temperature? Summary of the specific results are given.

  15. The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite

    Directory of Open Access Journals (Sweden)

    M. Schröder

    2013-03-01

    Full Text Available The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF aims at the provision and sound validation of well documented Climate Data Records (CDRs in sustained and operational environments. In this study, a total column water vapour path (WVPA climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I, a climatology of WVPA has been generated within the Hamburg Ocean–Atmosphere Fluxes and Parameters from Satellite (HOAPS framework. Within a research and operation transition activity the HOAPS data and operation capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, namely kriging, has been applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses and from the Japan Meteorological Agency (JMA–JRA. This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m−2. The absolute value of the bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m−2. For the period 1991–2006, the root mean square error (RMSE for both reanalyses is approximately 2 kg m−2. As SSM/I WVPA and radiances are assimilated into JMA and all ECMWF analyses and

  16. Removal of arsenic and iron removal from drinking water using coagulation and biological treatment.

    Science.gov (United States)

    Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Suja, Fatihah

    2016-02-01

    Effects of biological activated carbon (BAC), biological aerated filter (BAF), alum coagulation and Moringa oleifera coagulation were investigated to remove iron and arsenic contaminants from drinking water. At an initial dose of 5 mg/L, the removal efficiency for arsenic and iron was 63% and 58% respectively using alum, and 47% and 41% respectively using Moringa oleifera. The removal of both contaminants increased with the increase in coagulant dose and decrease in pH. Biological processes were more effective in removing these contaminants than coagulation. Compared to BAF, BAC gave greater removal of both arsenic and iron, removing 85% and 74%, respectively. Longer contact time for both processes could reduce the greater concentration of arsenic and iron contaminants. The addition of coagulation (at 5 mg/L dosage) and a biological process (with 15 or 60 min contact time) could significantly increase removal efficiency, and the maximum removal was observed for the combination of alum and BAC treatment (60 min contact time), with 100% and 98.56% for arsenic and iron respectively. The reduction efficiency of arsenic and iron reduced with the increase in the concentration of dissolved organics in the feedwater due to the adsorption competition between organic molecules and heavy metals.

  17. Process for removing sulfate anions from waste water

    Science.gov (United States)

    Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

    1997-01-01

    A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

  18. Analysis of Water Vapour Flux Between Alpine Wetlands Underlying the Surface and Atmosphere in the Source Region of the Yellow River

    Science.gov (United States)

    Xie, Y.; Wen, J.; Liu, R.; Wang, X.; JIA, D.

    2017-12-01

    Wetland underlying surface is sensitive to climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Previous studies, which focused on the forest, grassland and farmland ecosystems, lack research on the alpine wetlands. In addition, research on the environmental control mechanism of latent heat flux is still qualitative and lacks quantitative evaluations and calculations. Using data from the observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors (solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows: Due to the diurnal variations of solar radiation and wind speed, the diurnal variations of the Ω factor present a trend in which the Ω factor are small in the morning and large in the evening. Due to the vegetation growing cycle, the seasonal variations of the Ω factor present a reverse "U" trend . These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over the latent heat flux. This conforms to omega theory. The values for average absolute atmospheric factor (surface factor or total ) control exercised by solar radiation and water vapour pressure are 0.20 (0.02 or 0.22 ) and 0.005 (-0.07 or -0.06) W·m-2·Pa-1, respectively.. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on the latent heat flux. The average Ω factor is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between the

  19. Heavy metal removal from waste waters by ion flotation

    OpenAIRE

    Polat, Hürriyet; Erdoğan, D.

    2007-01-01

    Flotation studies were carried out to investigate the removal of heavy metals such as copper (II), zinc (II), chromium (III) and silver (I) from waste waters. Various parameters such as pH, collector and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol and methyl isobutyl carbinol (MIBC) were used as frothers. Metal removal reached about 74% under o...

  20. Removal of arsenic from drinking water by natural adsorbents

    OpenAIRE

    MD SHAHNOOR ALAM KHAN

    2017-01-01

    The presence of arsenic in groundwater has been reported in many countries across the world and it is a serious threat to public health. The aim of this study was to identify prospective natural materials with high arsenic adsorption capacity and durable hydraulic property to produce adequate flow of water. The comparative study identified Skye sand as the best natural adsorbent. The prototype household filter with Skye sand achieved complete removal of arsenic and iron. Arsenic removal by du...

  1. An "island" in the stratosphere - on the enhanced annual variation of water vapour in the middle and upper stratosphere in the southern tropics and subtropics

    Science.gov (United States)

    Lossow, Stefan; Garny, Hella; Jöckel, Patrick

    2017-09-01

    The amplitude of the annual variation in water vapour exhibits a distinct isolated maximum in the middle and upper stratosphere in the southern tropics and subtropics, peaking typically around 15° S in latitude and close to 3 hPa (˜ 40.5 km) in altitude. This enhanced annual variation is primarily related to the Brewer-Dobson circulation and hence also visible in other trace gases. So far this feature has not gained much attention in the literature and the present work aims to add more prominence. Using Envisat/MIPAS (Environmental Satellite/Michelson Interferometer for Passive Atmospheric Sounding) observations and ECHAM/MESSy (European Centre for Medium-Range Weather Forecasts Hamburg/Modular Earth Submodel System) Atmospheric Chemistry (EMAC) simulations we provide a dedicated illustration and a full account of the reasons for this enhanced annual variation.

  2. An “island” in the stratosphere – on the enhanced annual variation of water vapour in the middle and upper stratosphere in the southern tropics and subtropics

    Directory of Open Access Journals (Sweden)

    S. Lossow

    2017-09-01

    Full Text Available The amplitude of the annual variation in water vapour exhibits a distinct isolated maximum in the middle and upper stratosphere in the southern tropics and subtropics, peaking typically around 15° S in latitude and close to 3 hPa (∼  40.5 km in altitude. This enhanced annual variation is primarily related to the Brewer–Dobson circulation and hence also visible in other trace gases. So far this feature has not gained much attention in the literature and the present work aims to add more prominence. Using Envisat/MIPAS (Environmental Satellite/Michelson Interferometer for Passive Atmospheric Sounding observations and ECHAM/MESSy (European Centre for Medium-Range Weather Forecasts Hamburg/Modular Earth Submodel System Atmospheric Chemistry (EMAC simulations we provide a dedicated illustration and a full account of the reasons for this enhanced annual variation.

  3. Treatment technology for removing radon from small community water supplies

    International Nuclear Information System (INIS)

    Kinner, N.E.; Quern, P.A.; Schell, G.S.; Lessard, C.E.; Clement, J.A.

    1990-01-01

    This paper reports on the selection of an appropriate treatment system to remove radon from drinking water which depends primarily upon percent removal; capital and operating and maintenance costs; safety; raw water quality with respect to parameters such as Fe, Mn, bacteria, and organics. The radon removal efficiency of the diffused bubble and packed tower aeration exceeded 99% at A:W ratios of 15:1 and 5:1, respectively; the GAC system averaged 81 ± 7.7%. Though our field evaluations indicated that GAC systems may not be as efficient as aeration systems, the system tested was operated above design requirements for most of the study period. Other researchers have found removals of greater than 99% with GAC point-of-entry applications. Therefore, each of these processes has the potential to consistently remove 99% of the radon applied. However, even this percent removal may not be sufficient to meet an MCL in the range of 200 to 1000 pCi/L if the raw water contained more than 20,000 to 100,000 pCi/L, respectively

  4. Novel Photocatalytic Reactor Development for Removal of Hydrocarbons from Water

    Directory of Open Access Journals (Sweden)

    Morgan Adams

    2008-01-01

    Full Text Available Hydrocarbons contamination of the marine environment generated by the offshore oil and gas industry is generated from a number of sources including oil contaminated drill cuttings and produced waters. The removal of hydrocarbons from both these sources is one of the most significant challenges facing this sector as it moves towards zero emissions. The application of a number of techniques which have been used to successfully destroy hydrocarbons in produced water and waste water effluents has previously been reported. This paper reports the application of semiconductor photocatalysis as a final polishing step for the removal of hydrocarbons from two waste effluent sources. Two reactor concepts were considered: a simple flat plate immobilised film unit, and a new rotating drum photocatalytic reactor. Both units proved to be effective in removing residual hydrocarbons from the effluent with the drum reactor reducing the hydrocarbon content by 90% under 10 minutes.

  5. PHOSPHATES REMOVAL FROM REJECT WATER FROM DIGESTION OF SLUDGE

    Directory of Open Access Journals (Sweden)

    Elżbieta Sperczyńska

    2016-06-01

    Full Text Available The aim of the research work was to evaluate if coagulants used on technical scale are useful in phosphates removal from reject water. Effectiveness of phosphorus compounds removal from reject water from digestion of sewage sludge was examined. Selected prehydrolysed alkaline aluminium polychlorides were used. The results were compared to the ones obtained with aluminium sulphate. Reject water from digestion of sewage sludge form WWTP of 100 000 PE were examined. Commercial agents – prehydrolysed PAX 18, PAX XL10, PAX-XL1905 as well as aluminium sulphate were used. Various doses of coagulants: 0.7; 1.0; 1.5 – time higher than stoichiometric dose were applied. Stoichiometric dose was calculated based on chemical reaction of insoluble aluminium phosphate formation. Concentrations of Kiejdahl nitrogen (891 mgNKj/dm3, phosphates (125 mgPO43-/dm3 and organic compounds - COD (592 mgO2/dm3 in reject water were very high. The effectiveness of coagulation process increased as the doses of chemical agents increased. The most effective doses were the highest ones used during the experiment. The most effective agent was PAX 18 (96% removal efficiency. As the phosphates concentration decreased COD content declined simultaneously. Maximum COD removal (47% was obtained when highly alkaline PAX XL 1905 was used. Use of the lowest dose of Al2(SO43 allowed for 50% phosphates removal, whereas the lowest dose of PAX 18 decreased phosphates concentration by 83%.

  6. Fluoride Removal from Water by Reverse Osmosis Membrane

    Directory of Open Access Journals (Sweden)

    Sara Namavar

    2013-09-01

    Full Text Available As fluoride concentration in drinking water is one of the effective parameters in human health, finding the way to remove excess amount of fluoride from drinking water is very important in water supply projects. Today, with developing in technology and finding new methods, the use of membrane technology for producing fresh water get improved. In this study the efficiency of reverse osmosis method to remove fluoride from water was investigated. Initial concentration of fluoride, sulfate and electrical conductivity in feed water and the effect of associated cation with fluoride ion were studied. All tests adapted from “Standard Methods for Examination of Water and Wastewater”. Determination of fluoride concentration was done according the standard SPANDS method by using a spectrophotometer DR/5000. Obtain results show that with increasing in concentration of fluoride and sulfate and electrical conductivity in feed water the efficiency of RO membrane to remove fluoride reduced. In addition, this efficiency for CaF2 was higher than NaF.

  7. Colloids removal from water resources using natural coagulant: Acacia auriculiformis

    Science.gov (United States)

    Abdullah, M.; Roslan, A.; Kamarulzaman, M. F. H.; Erat, M. M.

    2017-09-01

    All waters, especially surface waters contain dissolved, suspended particles and/or inorganic matter, as well as several biological organisms, such as bacteria, algae or viruses. This material must be removed because it can affect the water quality that can cause turbidity and colour. The objective of this study is to develop water treatment process from Seri Alam (Johor, Malaysia) lake water resources by using natural coagulant Acacia auriculiformis pods through a jar test experiment. Jar test is designed to show the effectiveness of the water treatment. This process is a laboratory procedure that will simulate coagulation/flocculation with several parameters selected namely contact time, coagulant dosage and agitation speed. The most optimum percentage of colloids removal for each parameter is determined at 0.2 g, 90 min and 80 rpm. FESEM (Field-emission Scanning Electron Microscope) observed the small structures of final floc particles for optimum parameter in this study to show that the colloids coagulated the coagulant. All result showed that the Acacia auriculiformis pods can be a very efficient coagulant in removing colloids from water.

  8. Uranium removal from water by five aquatic plants

    International Nuclear Information System (INIS)

    Hu Nan; Ding Dexin; Li Guangyue; Wang Yongdong; Li Le; Zheng Jifang

    2012-01-01

    Hydroponic solution culture experiments were conducted on the growth of Eichhornia crassipes, Lemna minor L, Azolla imbircata, Potamogeton crispus, and Alligator alternanthera Herb in water with 0.15, 1.50 and 15.00 mg . L -1 concentrations of uranium, and on the uranium removal from the water by the aquatic plants. For the 21 days of hydroponic solution culture experiments, Azolla imbircata exhibited the strongest resistance to uranium and its growth inhibition rates induced by the water with 0.15, 1.50 and 15.00 mg · L -1 concentrations of uranium were 4.56%, 2.48%, 6.79%, respectively, and the uranium removal rates from the water by the plant amounted to 94%, 97% and 92%, respectively. Further experiments revealed that the most uranium removal could be achieved when 7.5 g Azolla imbircata was grown in 1 L of water, and the time required for the plant to reduce the uranium concentration in water with 1.25, 2.50, 5.00 and 10.00 mg · L -l concentrations of uranium below that stipulated in the national emission standards of China were 17, 19, 23 and 25 days, respectively. The results have laid foundation for further studies of phytoremediation of uranium contaminated water. (authors)

  9. Removal of Arsenic from Drinking Water by Adsorption and Coagulation

    Science.gov (United States)

    Zhang, M.; Sugita, H.; Hara, J.; Takahashi, S.

    2013-12-01

    Removal of arsenic from drinking water has been an important issue worldwide, which has attracted greater attentions in recent years especially for supplying safe drinking water in developing countries. Although many kinds of treatment approaches that are available or applicable both in principle and practice, such as adsorption, coagulation, membrane filtration, ion exchange, biological process, electrocoagulation and so on, the first 2 approaches (i.e., adsorption and coagulation) are most promising due to the low-cost, high-efficiency, simplicity of treating systems, and thus can be practically used in developing countries. In this study, a literature survey on water quality in Bangladesh was performed to understand the ranges of arsenic concentration and pH of groundwater in Bangladesh. A series of tests were then organized and performed to investigate the effects of arsenic concentration, arsenic forms, pH, chemical compositions of the materials used for adsorption and coagulation, particle size distribution and treatment time on quality of treated water. The experimental results obtained in the study illustrated that both adsorption and coagulation can be used to effectively reduce the concentrations of either arsenic (V) or arsenic (III) from the contaminated water. Coagulation of arsenic with a magnesium-based material developed in this study can be very effective to remove arsenic, especially arsenic (V), from contaminated water with a concentration of 10 ppm to an undetectable level of 0.002 ppm by ICP analyses. Compared to arsenic (III), arsenic (V) is easier to be removed. The materials used for adsorption and coagulation in this study can remove arsenic (V) up to 9 mg/g and 6 mg/g, and arsenic (III) up to 4 mg/g and 3 mg/g, respectively, depending on test conditions and compositions of the materials being used. The control of pH during treatment can be a challenging technical issue for developing both adsorbent and coagulant. Keywords: Water Treatment

  10. Removal of some radionuclides from water by bioaccumulation

    Energy Technology Data Exchange (ETDEWEB)

    Miskovic, D.; Conkic, L.; Dalmacija, B.; Gantar, M. (Trg D. Obradvica 3, Novi Sad (Yugoslavia). Faculty of Sciences)

    1992-01-01

    First objective of this study was to investigate the application of biologically activated carbon (BAC) as well as its comparison to adsorption, with the aim of removing some radionuclides from water. The isotopes Cs[sup 134] and Cs[sup 137] were bioaccumulated by BAC up to 50%, while the I[sup 131] isotope was only physicochemically adsorbed (about 40%). Also, the process of radionuclides (Cs[sup 137], Ce[sup 139], Co[sup 57], Co[sup 60]) fixation on blue-green algae (Nostoc sp.) was investigated. The kinetics of the removal of these radionuclides from water was recorded. It was found that after a contact period of about half an hour 40-70% of the activity was removed. (Author).

  11. Fluoride removal studies in water using natural materials : technical ...

    African Journals Online (AJOL)

    Excess fluoride in water causes health hazards to the natural environment. The removal of fluoride was attempted using natural materials such as red soil, charcoal, brick, fly-ash and serpentine. Each material was set up in a column for a known volume and the defluoridation capacities of these materials were studied with ...

  12. Fluoride removal from rural spring water using wood ash

    CSIR Research Space (South Africa)

    Makhado, R

    2006-05-01

    Full Text Available This paper presents an overview of a report on an investigation on the use of cheap wood ash as an effective means of removing excess fluoride from drinking water used by an impoverished rural community of the Didi village in Limpopo province....

  13. Removal of organic compounds from shale gas flowback water

    NARCIS (Netherlands)

    Butkovskyi, Andrii; Faber, Ann-Hélène; Wang, Yue; Grolle, Katja; Hofman-Caris, Roberta; Bruning, Harry; Van Wezel, Annemarie P.; Rijnaarts, Huub H M

    2018-01-01

    Ozonation, sorption to granular activated carbon and aerobic degradation were compared as potential treatment methods for removal of dissolved organic carbon (DOC) fractions and selected organic compounds from shale gas flowback water after pre-treatment in dissolved air flotation unit. Flowback

  14. Removal of antibiotics from surface and distilled water in conventional water treatment processes

    Science.gov (United States)

    Adams, C.; Wang, Y.; Loftin, K.; Meyer, M.

    2002-01-01

    Conventional drinking water treatment processes were evaluated under typical water treatment plant conditions to determine their effectiveness in the removal of seven common antibiotics: carbadox, sulfachlorpyridazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfathiazole, and trimethoprim. Experiments were conducted using synthetic solutions prepared by spiking both distilled/ deionized water and Missouri River water with the studied compounds. Sorption on Calgon WPH powdered activated carbon, reverse osmosis, and oxidation with chlorine and ozone under typical plant conditions were all shown to be effective in removing the studied antibiotics. Conversely, coagulation/flocculation/sedimentation with alum and iron salts, excess lime/soda ash softening, ultraviolet irradiation at disinfection dosages, and ion exchange were all relatively ineffective methods of antibiotic removal. This study shows that the studied antibiotics could be effectively removed using processes already in use many water treatment plants. Additional work is needed on by-product formation and the removal of other classes of antibiotics.

  15. Simultaneous retrieval of water vapour, temperature and cirrus clouds properties from measurements of far infrared spectral radiance over the Antarctic Plateau

    Science.gov (United States)

    Di Natale, Gianluca; Palchetti, Luca; Bianchini, Giovanni; Del Guasta, Massimo

    2017-03-01

    The possibility separating the contributions of the atmospheric state and ice clouds by using spectral infrared measurements is a fundamental step to quantifying the cloud effect in climate models. A simultaneous retrieval of cloud and atmospheric parameters from infrared wideband spectra will allow the disentanglement of the spectral interference between these variables. In this paper, we describe the development of a code for the simultaneous retrieval of atmospheric state and ice cloud parameters, and its application to the analysis of the spectral measurements acquired by the Radiation Explorer in the Far Infrared - Prototype for Applications and Development (REFIR-PAD) spectroradiometer, which has been in operation at Concordia Station on the Antarctic Plateau since 2012. The code performs the retrieval with a computational time that is comparable with the instrument acquisition time. Water vapour and temperature profiles and the cloud optical and microphysical properties, such as the generalised effective diameter and the ice water path, are retrieved by exploiting the 230-980 cm-1 spectral band. To simulate atmospheric radiative transfer, the Line-By-Line Radiative Transfer Model (LBLRTM) has been integrated with a specifically developed subroutine based on the δ-Eddington two-stream approximation, whereas the single-scattering properties of cirrus clouds have been derived from a database for hexagonal column habits. In order to detect ice clouds, a backscattering and depolarisation lidar, co-located with REFIR-PAD has been used, allowing us to infer the position and the cloud thickness to be used in the retrieval. A climatology of the vertical profiles of water vapour and temperature has been performed by using the daily radiosounding available at the station at 12:00 UTC. The climatology has been used to build an a priori profile correlation to constrain the fitting procedure. An optimal estimation method with the Levenberg-Marquardt approach has been

  16. Carbon Nanotubes Technology for Removal of Arsenic from Water

    Directory of Open Access Journals (Sweden)

    Ali Naghizadeh

    2012-08-01

    Full Text Available Please cite this article as: Naghizadeh A, Yari AR, Tashauoei HR, Mahdavi M, Derakhshani E, Rahimi R, Bahmani P. Carbon nanotubes technology for removal of arsenic from water. Arch Hyg Sci 2012;1(1:6-11. Aims of the Study: This study was aimed to investigate the adsorption mechanism of the arsenic removal from water by using carbon nanotubes in continuous adsorption column. Materials & Methods: Independent variables including carbon nanotubes dosage, contact time and breakthrough point were carried out to determine the influence of these parameters on the adsorption capacity of the arsenic from water. Results: Adsorption capacities of single wall and multiwall carbon nanotubes were about 148 mg/g and 95 mg/g respectively. The experimental data were analyzed using Langmuir and Freundlich isotherm models and equilibrium data indicate the best fit obtained with Langmuir isotherm model. Conclusions: Carbon nanotubes can be considered as a promising adsorbent for the removal of arsenic from large volume of aqueous solutions. References: 1. Lomaquahu ES, Smith AH. Feasibility of new epidemiology studies on arsenic exposures at low levels. AWWA Inorganic Contaminants Workshop. San Antonio; 1998. 2. Burkel RS, Stoll RC. Naturally occurring arsenic in sandstone aquifer water supply wells of North Eastern Wisconsin. Ground Water Monit Remediat 1999;19(2:114-21. 3. Mondal P, Majumder CB, Mohanty B. Laboratory based approaches for arsenic remediation from contaminated water: recent developments. J Hazard Mater 2006;137(1: 464-79. 4. Meenakshi RCM. Arsenic removal from water: a review. Asian J Water Environ Pollut 2006;3(1:133-9. 5. Wickramasinghe SR, Binbing H, Zimbron J, Shen Z, Karim MN. Arsenic removal by coagulation and filtration: comparison of ground waters from United States and Bangladesh. Desalination 2004;169:231-44. 6. Hossain MF. Arsenic contamination in Bangladesh-an overview. Agric Ecosyst Environ 2006;113(1-4:1-16. 7. USEPA, Arsenic. Final

  17. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    Science.gov (United States)

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg + ), ethylmercury (EtHg + ) and inorganic mercury (Hg 2+ ) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL -1 for EtHg + and 5-450ngL -1 for MeHg + and Hg 2+ . Limits of detection were 3.0ngL -1 for EtHg + and 1.5ngL -1 for MeHg + and Hg 2+ . Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Pollutants in drinking water - sources, harmful effects and removal procedures

    International Nuclear Information System (INIS)

    Qadeer, R.

    2005-01-01

    The underground water resources available for human consumption are being continuously contaminated by the natural sources and anthropogenic activities. The pollutants include toxic microorganism, inorganic and organic chemicals and radionuclide etc. This is an acute problem in our country, where free style way of disposal of industrial effluents into the natural water bodies contaminates the surface and ground water. These contaminants make their way into human body through contaminated drinking water, which leads to the malfunctioning of the body organs. Details of some pollutants present in drinking water, their source and harmful effects on human beings are reviewed in this communication Merits and demerits of methods used to remove the pollutants from drinking water are also discussed. (author)

  19. Sorbents for phosphate removal from agricultural drainage water

    DEFF Research Database (Denmark)

    Lyngsie, Gry

    Subsurface transport of phosphate (P) from fertilized agricultural fields to freshwaters may lead to eutrophication and reduced biodiversity in inland waters. Mitigation of eutrophic waters is difficult and costly. Reduction of P export to surface waters using filters installed in agricultural...... drains comprising P sorbing materials (PSM) may be a more efficient and cost-effective way to improve water quality. Several materials have been proposed as PSMs for use for cleaning agricultural drainage water. The objective of the present study was to provide data on sorption behavior among a variety...... of PSMs in order to select a material that can quickly remove P from runoff water at both base and peak flow. This was done by screening 15 “local” PSMs’ for their ability to sorb and retain low orthophosphate concentrations (0-161 µM) at short equilibration time (

  20. Alternative technology for arsenic removal from drinking water

    Directory of Open Access Journals (Sweden)

    Purenović Milovan

    2007-01-01

    Full Text Available Arsenic is a naturally occurring element in water, food and air. It is known as a poison, but in very small quantities it is showed to be an essential element. Actual problem in the world is arsenic removal from drinking water using modern and alternative technology, especially because EPA's and other international standards have reduced MCL from 50 to 10 ug/1. Because of rivers and lakes pollution, in a number of plants for natural water purification, average concentrations of arsenic in water are up to 100 ug/1. According to MCL, present technologies are unadjusted for safely arsenic removal for concentrations below of 10 ug/1. This fact has inspired many companies to solve this problem adequately, by using an alternative technologies and new process able materials. In this paper the observation of conventional and the alternative technologies will be given, bearing in mind complex chemistry and electrochemistry of arsenic, formation of colloidal arsenic, which causes the biggest problems in water purification technologies. In this paper many results will be presented, which are obtained using the alternative technologies, as well as the newest results of original author's investigations. Using new nanomaterials, on Pilot plant "VALETA H2O-92", concentration of arsenic was removed far below MLC value.

  1. Removal of organic pollutants from produced water using Fenton oxidation

    Directory of Open Access Journals (Sweden)

    Afzal Talia

    2018-01-01

    Full Text Available Produced water (PW is the largest stream of wastewater from oil and gas exploration. It is highly polluted and requires proper treatment before disposal. The main objective of this study was to investigate the effectiveness of Fenton oxidation in degradation of organic matter in PW. The role of operating factors viz., H2O2 concentration (0.12 × 10-3 moles/L to 3 moles/L, [H2O2]/[Fe2+] molar ratio (2 to 75, and reaction time (30 to 200 minutes, on COD removal was determined through a series of batch experiments conducted in acidic environment at room temperature. The experiments were conducted with 500 mL PW samples in 1L glass beakers covered on the outside with aluminum foil to protect them from sunlight. Pre-decided amounts of ferrous sulfate heptahydrate (FeSO4.7H2O and hydrogen peroxide (H2O2 were added to initiate the Fenton reaction. An increase in COD removal was observed with increase in reaction time and [H2O2]/[Fe2+] molar ratio. COD removal also increased with H2O2 concentration up to 0.01 moles/L; further increase in H2O2 concentration decreased the COD removal efficiency. Over 90% COD removal was achieved under optimum reaction conditions. The study indicates that Fenton oxidation is effective for remediation of PW in terms of organic matter removal.

  2. Removal of organic pollutants from produced water using Fenton oxidation

    Science.gov (United States)

    Afzal, Talia; Hasnain Isa, Mohamed; Mustafa, Muhammad Raza ul

    2018-03-01

    Produced water (PW) is the largest stream of wastewater from oil and gas exploration. It is highly polluted and requires proper treatment before disposal. The main objective of this study was to investigate the effectiveness of Fenton oxidation in degradation of organic matter in PW. The role of operating factors viz., H2O2 concentration (0.12 × 10-3 moles/L to 3 moles/L), [H2O2]/[Fe2+] molar ratio (2 to 75), and reaction time (30 to 200 minutes), on COD removal was determined through a series of batch experiments conducted in acidic environment at room temperature. The experiments were conducted with 500 mL PW samples in 1L glass beakers covered on the outside with aluminum foil to protect them from sunlight. Pre-decided amounts of ferrous sulfate heptahydrate (FeSO4.7H2O) and hydrogen peroxide (H2O2) were added to initiate the Fenton reaction. An increase in COD removal was observed with increase in reaction time and [H2O2]/[Fe2+] molar ratio. COD removal also increased with H2O2 concentration up to 0.01 moles/L; further increase in H2O2 concentration decreased the COD removal efficiency. Over 90% COD removal was achieved under optimum reaction conditions. The study indicates that Fenton oxidation is effective for remediation of PW in terms of organic matter removal.

  3. Experiments on aerosol removal by high-pressure water spray

    Energy Technology Data Exchange (ETDEWEB)

    Corno, Ada del, E-mail: delcorno@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Morandi, Sonia, E-mail: morandi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Parozzi, Flavio, E-mail: parozzi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Araneo, Lucio, E-mail: lucio.araneo@polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy); CNR-IENI, via Cozzi 53, I-20125 Milano (Italy); Casella, Francesco, E-mail: francesco2.casella@mail.polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy)

    2017-01-15

    Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m{sup 3}. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m{sup 3}. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was

  4. Removal of Sulfate from Waste Water by Activated Carbon

    OpenAIRE

    Mohammed Sadeq Salman

    2009-01-01

    Activated carbon was Produced from coconut shell and was used for removing sulfate from industrial waste water in batch Processes. The influence of various parameter were studied such as pH (4.5 9.) , agitation time (0 120)min and adsorbent dose (2 10) gm.The Langmuir and frandlich adsorption capacity models were been investigated where showed there are fitting with langmmuir model with squre regression value ( 0.76). The percent of removal of sulfate (22% - 38%) at (PH=7) in the isotherm ...

  5. Heavy metal removal from waste waters by ion flotation.

    Science.gov (United States)

    Polat, H; Erdogan, D

    2007-09-05

    Flotation studies were carried out to investigate the removal of heavy metals such as copper (II), zinc (II), chromium (III) and silver (I) from waste waters. Various parameters such as pH, collector and frother concentrations and airflow rate were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol and methyl isobutyl carbinol (MIBC) were used as frothers. Metal removal reached about 74% under optimum conditions at low pH. At basic pH it became as high as 90%, probably due to the contribution from the flotation of metal precipitates.

  6. Experiments on aerosol removal by high-pressure water spray

    International Nuclear Information System (INIS)

    Corno, Ada del; Morandi, Sonia; Parozzi, Flavio; Araneo, Lucio; Casella, Francesco

    2017-01-01

    Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO_2 particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m"3. • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO_2 particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m"3. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was detected with 1

  7. Biostimulation strategies to enhance manganese removal in drinking water biofilters

    DEFF Research Database (Denmark)

    Breda, Inês Lousinha Ribeiro; Ramsay, Loren; Søborg, Ditte

    to national drinking water criteria. The period during which virgin filter media matures into a fully functional biofilter is designated as the start-up period. The duration of a start-up for efficient manganese removal varies from weeks to more than a year. The aim of this study was to investigate...... growth and activity of specific bacteria. Biostimulation of virgin media to enhance initial manganese removal using different amendments strategies is possible especially in the early stages of filter development whereas autocatalytic processes appear to become dominant with time. The complex...

  8. La3+-modified activated alumina for fluoride removal from water

    International Nuclear Information System (INIS)

    Cheng, Jiemin; Meng, Xiaoguang; Jing, Chuanyong; Hao, Jumin

    2014-01-01

    Graphical abstract: - Highlights: • A La 3+ -modified activated alumina adsorbent was prepared for effective removal F − . • SEM/EDS and EXAFS analyses determined the formation of La(OH) 3 coating on the AA. • The La-AA had much high adsorption rate and capacity than the AA. • The La-AA was promising adsorbent for effective removal of F − from water. - Abstract: A La 3+ -modified activated alumina (La-AA) adsorbent was prepared for effective removal of fluoride from water. The surface properties of adsorbent were characterized with zeta potential analysis, SEM-EDS and EXAFS. Batch and column experiments were conducted to evaluate improvement of F − removal by the La-AA. SEM/EDS and EXAFS analyses determined the formation of La(OH) 3 coating on the AA and strong bonding interactions between La 3+ and the Al atoms. The points of zero charge (pH PZC ) of AA and La-AA were at pH 8.94 and 9.57, respectively. Batch experimental results indicated that the La-AA had much higher adsorption rate and capacity than the AA. The F − adsorption processes on La-AA and AA followed the pseudo-second-order kinetics and the Langmuir isotherm. Column filtration results shows that the La-AA and AA treated 270 and 170 bed volumes of the F − -spiked tap water, respectively, before F − breakthrough occurred. The results demonstrated that the La-AA was a promising adsorbent for effective removal of F − from water

  9. Removal of arsenic from contaminated water using coagulation enhanced microfiltration

    International Nuclear Information System (INIS)

    Volchek, K.; Velicogna, D.; Dumouchel, A.; Wong, W.P.; Brown, C.E.

    2002-01-01

    Results of an innovative arsenic removal process were presented. The process is based on a combination of coagulation and microfiltration processes. Coagulation-Enhanced Microfiltration (CEMF) may eventually become a full-scale commercial technology. This study focused on the process with respect to groundwater treatment because of the importance of arsenic contamination in drinking water. Most experiments were bench-scale using tap water spiked with arsenic. Ferric chloride, which is commonly used in arsenic removal processes was also added. In addition, some tests were conducted on actual arsenic-contaminated water from the effluent treatment plant of a former mining site in Ontario. Results indicate a high arsenic removal efficiency in both spiked and actual water solutions. The microfiltration significantly reduced the level of arsenic in the treatment. This paper described the characteristics of membrane separation. It also presented information regarding chemically enhanced membrane filtration and coagulation-enhanced microfiltration. Bench-scale tests were conducted with both tubular membranes and with immersed capillary membranes. The effect of iron to arsenic ratios on the effectiveness of the system was also tested. It was recommended that future research should include a field study of the process on a pilot-scale to optimize process parameters and to accurately determine the cost of the process. 16 refs., 8 tabs., 9 figs

  10. Aluminium removal from water after defluoridation with the electrocoagulation process.

    Science.gov (United States)

    Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

    2015-01-01

    Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

  11. Removing efficiency of radon from water by different methods

    International Nuclear Information System (INIS)

    Muellerova, M.; Holy, K.; Gulasova, Z.; Polaskova, A.

    2008-01-01

    In this contribution problem of radon removing from water samples by different methods was tested. Lowest efficiency of deemanation was achieved at tossing of water from one vessel into the other. For increasing of efficiency deemanation of radon use of needle-bath principle was also used. Low efficiency deemanation was found at trapping of radon from sample of water by toluene (83 ± 5) %, too. Reversal highest efficiency deemanation of radon from water was reached at aerating by argon (95 ± 6)%. It is shown, that reduction of volume activity of radon in water under 0.1 Bq/dm l - 3 is big problem. Suppression of this limit will claim use of more completion and sophistic approaches. (author)

  12. Survival of fish upon removal of cyanide from water

    International Nuclear Information System (INIS)

    Gacsi, Mariann; Czegeny, Ildiko; Nagy, Gabor; Banfalvi, Gaspar

    2005-01-01

    The effects of potassium cyanide and the removal of cyanide from water in vivo on the survival of fish were investigated. This research was initiated because of the catastrophe that took place at the end of January 2000 in the Carpathian basin, when an enormous amount of cyanide pollution swept through the Samos and Tisza rivers, and then to the Danube. Since nothing was done against the disaster, we have suggested a chemical solution to remove cyanide from waterways (Chem. Innovat. 30 (2000b) 53). Based on experiments, we describe that the most effective and harmless way to remove cyanide and to save the lives of fish from 40 to 160x the lethal doses of cyanide is to use carbogen gas containing 5% carbon dioxide and 95% oxygen followed by aeration with air

  13. Validation of water vapour profiles (version 13 retrieved by the IMK/IAA scientific retrieval processor based on full resolution spectra measured by MIPAS on board Envisat

    Directory of Open Access Journals (Sweden)

    M. Milz

    2009-07-01

    Full Text Available Vertical profiles of stratospheric water vapour measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS with the full resolution mode between September 2002 and March 2004 and retrieved with the IMK/IAA scientific retrieval processor were compared to a number of independent measurements in order to estimate the bias and to validate the existing precision estimates of the MIPAS data. The estimated precision for MIPAS is 5 to 10% in the stratosphere, depending on altitude, latitude, and season. The independent instruments were: the Halogen Occultation Experiment (HALOE, the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS, the Improved Limb Atmospheric Spectrometer-II (ILAS-II, the Polar Ozone and Aerosol Measurement (POAM III instrument, the Middle Atmospheric Water Vapour Radiometer (MIAWARA, the Michelson Interferometer for Passive Atmospheric Sounding, balloon-borne version (MIPAS-B, the Airborne Microwave Stratospheric Observing System (AMSOS, the Fluorescent Stratospheric Hygrometer for Balloon (FLASH-B, the NOAA frostpoint hygrometer, and the Fast In Situ Hygrometer (FISH. For the in-situ measurements and the ground based, air- and balloon borne remote sensing instruments, the measurements are restricted to central and northern Europe. The comparisons to satellite-borne instruments are predominantly at mid- to high latitudes on both hemispheres. In the stratosphere there is no clear indication of a bias in MIPAS data, because the independent measurements in some cases are drier and in some cases are moister than the MIPAS measurements. Compared to the infrared measurements of MIPAS, measurements in the ultraviolet and visible have a tendency to be high, whereas microwave measurements have a tendency to be low. The results of χ2-based precision validation are somewhat controversial among the comparison estimates. However, for comparison instruments whose error budget also includes

  14. Modelling (vapour + liquid) and (vapour + liquid + liquid) equilibria of {water (H2O) + methanol (MeOH) + dimethyl ether (DME) + carbon dioxide (CO2)} quaternary system using the Peng-Robinson EoS with Wong-Sandler mixing rule

    International Nuclear Information System (INIS)

    Ye Kongmeng; Freund, Hannsjoerg; Sundmacher, Kai

    2011-01-01

    Highlights: → Phase behaviour modelling of H 2 O-MeOH-DME under pressurized CO 2 (anti-solvent) using PRWS. → PRWS-UNIFAC-PSRK has better performance than PRWS-UNIFAC-Lby in general. → Reliable to extend the VLE and VLLE phase behaviour from binary to multicomponent systems. → Successful prediction of the VLE and VLLE of binary, ternary, and quaternary systems. → Potential to apply the model for designing new DME separation process. - Abstract: The (vapour + liquid) equilibria (VLE) and (vapour + liquid + liquid) equilibria (VLLE) binary data from literature were correlated using the Peng-Robinson (PR) equation of state (EoS) with the Wong-Sandler mixing rule (WS). Two group contribution activity models were used in the PRWS: UNIFAC-PSRK and UNIFAC-Lby. The systems were successfully extrapolated from the binary systems to ternary and quaternary systems. Results indicate that the PRWS-UNIFAC-PSRK generally displays a better performance than the PRWS-UNIFAC-Lby.

  15. Technical solutions for tritium removal from Cernavoda NPP heavy water systems

    International Nuclear Information System (INIS)

    Barariu, Gheorghe; Panait, Adrian

    2002-01-01

    In CANDU nuclear plants 2400 KCi/GW(e) - year tritium is generated. At a CANDU - 600 reactor similar to Cernavoda NPP Unit 1, 1500 KCi/year of tritium is generated 95% being in the D 2 O moderator, which can achieve a radioactivity level of 80 - 100 Ci/kg. Tritium in heavy water contributes with 30 - 50% to the doses received by operation personnel and with 20% to the radioactivity released to the environment. The extraction of tritium heavy water at CANDU reactors implies the following possibilities: - the radioactivity level reduction in the operation area; - the maintenance and repair cost reduction due to reduction of personnel protection measures and increased labor productivity; - the increase of NPP utilization factor by shutdown time reduction for maintenance and repair; - tritium concentration reduction from technological systems, ensuring thus the possibility of redesigning the systems in order to lower the cost of investment; - profitable use of extracted tritium. Technical measures provided by AECL project for CANDU 600 at Cernavoda make possible to satisfy the current standards concerning tritium concentration in the operation area atmosphere of 5 x 10 -6 Ci/m 3 . The regulations recommend that the radioactivity level should be maintained as low as possible in conformity with ALARA principles. Also, it is possible that norms will become more restrictive in the future, so the tritium removal technology is a good preventive measure which may become very necessary. The methods, which currently reached the industrial or pilot stages, are based on catalyzed chemical exchange, the heavy water electrolysis, and deuterium distillation. They are known as: VPCE - Vapour Phase Catalytic Exchange; LPCE - Liquid Phase Catalytic Exchange; DE - Direct Electrolysis; CD - Cryogenic Distillation. As transfer processes the catalyzed chemical exchange and heavy water electrolysis are used while concentration of tritium gas is done by cryogenic distillation. At present the

  16. Removal of arsenic from drinking water using rice husk

    Science.gov (United States)

    Asif, Zunaira; Chen, Zhi

    2017-06-01

    Rice husk adsorption column method has proved to be a promising solution for arsenic (As) removal over the other conventional methods. The present work investigates the potential of raw rice husk as an adsorbent for the removal of arsenic [As(V)] from drinking water. Effects of various operating parameters such as diameter of column, bed height, flow rate, initial arsenic feed concentration and particle size were investigated using continuous fixed bed column to check the removal efficiency of arsenic. This method shows maximum removal of As, i.e., 90.7 % under the following conditions: rice husk amount 42.5 g; 7 mL/min flow rate in 5 cm diameter column at the bed height of 28 cm for 15 ppb inlet feed concentration. Removal efficiency was increased from 83.4 to 90.7 % by reducing the particle size from 1.18 mm to 710 µm for 15 ppb concentration. Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior. The effect of different operating parameters on the column adsorption was determined using breakthrough curves. In the present study, three kinetic models Adam-Bohart, Thomas and Yoon-Nelson were applied to find out the saturated concentration, fixed bed adsorption capacity and time required for 50 % adsorbate breakthrough, respectively. At the end, solidification was done for disposal of rice husk.

  17. Membrane Bioprocesses for Pharmaceutical Micropollutant Removal from Waters

    Directory of Open Access Journals (Sweden)

    Matthias de Cazes

    2014-10-01

    Full Text Available The purpose of this review work is to give an overview of the research reported on bioprocesses for the treatment of domestic or industrial wastewaters (WW containing pharmaceuticals. Conventional WW treatment technologies are not efficient enough to completely remove all pharmaceuticals from water. Indeed, these compounds are becoming an actual public health problem, because they are more and more present in underground and even in potable waters. Different types of bioprocesses are described in this work: from classical activated sludge systems, which allow the depletion of pharmaceuticals by bio-degradation and adsorption, to enzymatic reactions, which are more focused on the treatment of WW containing a relatively high content of pharmaceuticals and less organic carbon pollution than classical WW. Different aspects concerning the advantages of membrane bioreactors for pharmaceuticals removal are discussed, as well as the more recent studies on enzymatic membrane reactors to the depletion of these recalcitrant compounds.

  18. Radon-removal techniques for small community public water supplies

    International Nuclear Information System (INIS)

    Kinner, N.E.; Malley, J.P.; Clement, J.A.; Quern, P.A.; Schell, G.S.

    1990-08-01

    The report presents the results of an evaluation, performed by the University of New Hampshire--Environmental Research Group (ERG), of radon removal in small community water supplies using full-scale granular activated carbon adsorption, diffused bubble aeration and packed tower aeration. Various low technology alternatives, such as loss in a distribution system and addition of coarse bubble aeration to a pilot-scale atmospheric storage tank were also evaluated. The report discusses each of the treatment alternatives with respect to their radon removal efficiency, potential problems (i.e., waste disposal, radiation exposure and intermedia pollution), and economics in small community applications. In addition, several sampling methods, storage times, scintillation cocktails and extraction procedures currently used in the liquid scintillation technique for analysis of radon in water were compared

  19. Removal of uranium from water media by bentonite and zeolite

    International Nuclear Information System (INIS)

    Viglasova, E.; Krajnak, A.; Galambos, M.; Rosskopfova, O.

    2014-01-01

    The removal and recovery of uranium from contaminated surface, environment and ground water, as result of nuclear industries, has attracted more and more attentions. Several methods are available for removing of uranium, but adsorption among the others, is the most attractive. In case of management of radioactive waste, the adsorption of radionuclides plays significant role. Among the natural sorbents applied to the adsorption of uranium zeolites and bentonites offer a number of advantages. The main aims of this work are investigations of adsorption properties of Greek zeolite Metaxades and Greek bentonite Kimolos during adsorption of uranium from water solutions, comparison of their adsorption characteristics, fitting with isotherms (Freundlich, Langmuir and DR isotherm) and its behaviour during kinetics process influenced by temperature. (authors)

  20. Improved water vapour spectroscopy in the 4174–4300 cm−1 region and its impact on SCIAMACHY HDO/H2O measurements

    Directory of Open Access Journals (Sweden)

    R. A. Scheepmaker

    2013-04-01

    Full Text Available The relative abundance of the heavy water isotopologue HDO provides a deeper insight into the atmospheric hydrological cycle. The SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY allows for global retrievals of the ratio HDO/H2O in the 2.3 micron wavelength range. However, the spectroscopy of water lines in this region remains a large source of uncertainty for these retrievals. We therefore evaluate and improve the water spectroscopy in the range 4174–4300 cm−1 and test if this reduces systematic uncertainties in the SCIAMACHY retrievals of HDO/H2O. We use a laboratory spectrum of water vapour to fit line intensity, air broadening and wavelength shift parameters. The improved spectroscopy is tested on a series of ground-based high resolution FTS spectra as well as on SCIAMACHY retrievals of H2O and the ratio HDO/H2O. We find that the improved spectroscopy leads to lower residuals in the FTS spectra compared to HITRAN 2008 and Jenouvrier et al. (2007 spectroscopy, and the retrievals become more robust against changes in the retrieval window. For both the FTS and SCIAMACHY measurements, the retrieved total H2O columns decrease by 2–4% and we find a negative shift of the HDO/H2O ratio, which for SCIAMACHY is partly compensated by changes in the retrieval setup and calibration software. The updated SCIAMACHY HDO/H2O product shows somewhat steeper latitudinal and temporal gradients and a steeper Rayleigh distillation curve, strengthening previous conclusions that current isotope-enabled general circulation models underestimate the variability in the near-surface HDO/H2O ratio.

  1. An atlas of mean distribution of precipitable water vapour over the tropical Indian Ocean for the year 1979

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Sathe, P.V.; Muraleedharan, P.M.; Rao, L.V.G.

    The monthly mean maps of the precipitable water (PW) over the tropical Indian Ocean are prepared using the data derived from the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) sensor for the period January to December, 1979. The PW...

  2. Clinoptilolite in Drinking Water Treatment for Ammonia Removal

    Directory of Open Access Journals (Sweden)

    H. M. Abd El-Hady

    2001-01-01

    Full Text Available In most countries today the removal of ammonium ions from drinking water has become almost a necessity. The natural zeolite clinoptiloliteis mined commercially in many parts of the world. It is a selective exchanger for the ammonium cation, and this has prompted its use in water treatment, wastewater treatment, swimming pools and fish farming. The work described in this paper provides dynamic data on cation exchange processes in clinoptilolite involving the NH4 +, Ca+2 and Mg+2 cations. We used material of natural origin – clinoptilolite from Nižný Hrabovec in Slovakia (particle-size 3–5 mm. The breakthrough capacity was determined by dynamic laboratory investigations, and we investigated the influence of thermal pretreatment of clinoptilolite and the concentration of regenerant solution (2, 5, and 10% NaCl. The concentrations of ammonium ion inputs in the tap water that we used were 10, 5, and 2 mg NH4 + l_1 and down to levels below 0.5 mg NH4 + l_1. The experimental results show that repeated pretreatment sufficiently improves the zeolite’s properties, and the structure of clinoptilolite remains unchanged during the loading and regeneration cycles. Ammonium removal capacities were increased by approximately 40 % and 20 % for heat-treated zeolite samples. There was no difference between the regenerates for 10% and 5% NaCl. We conclude that the use of zeolite is an attractive and promising method for ammonium removal.

  3. Aluminum-Based Water Treatment Residue Reuse for Phosphorus Removal

    Directory of Open Access Journals (Sweden)

    Lai Yoke Lee

    2015-04-01

    Full Text Available Aluminum-based water treatment residue (Al-WTR generated during the drinking water treatment process is a readily available recycled material with high phosphorus (P adsorption capacity. The P adsorption capacity of Al-WTR generated from Singapore’s water treatment plant was evaluated with reference to particle size range, adsorption pH and temperature. Column tests, with WTR amendments in sand with and without compost, were used to simulate the bioretention systems. The adsorption rate decreased with increasing WTR sizes. Highest P adsorption capacity, 15.57 mg PO43−-P/g WTR, was achieved using fine WTR particles (>50% particles at less than 0.30 mm. At pH 4, the contact time required to reduce effluent P concentration to below the detectable range was half compared with pH 7 and 9. The adsorption rate observed at 40 ± 2 °C was 21% higher compared with that at 30 ± 2 °C. Soil mixes amended with 10% WTR and compost were able to maintain consistently high (90% total phosphorus (TP removal efficiency at a TP load up to 6.45 g/m3. In contrast, TP removal efficiencies associated with columns without WTR amendment decreased to less than 45% as the TP load increased beyond 4.5 g/m3. The results showed that WTR application is beneficial for enhanced TP removal in bioretention systems.

  4. Use of polymeric resins for removing contaminants from oily waters

    Energy Technology Data Exchange (ETDEWEB)

    Clarisse, M.D.; Queiros, Y.G.C.; Mauro, A.C.; Lucas, E.F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas; Barbosa, C.C.R. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Barbosa, L.C.F.; Louvisse, A.M.T. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    Polymeric resins are being tried as an alternative material for treating oily waters from the petroleum industry, which have already been treated by conventional methods. The objective of this work has been to evaluate the purification degree of synthetic oily waters when treated in fixed bed columns packed with polymeric resins made up of hydrophilic and lipophilic moieties. The analysis used for characterizing the total grease and oil content (TOG) was fluorimetry. Starting oily waters of average TOG 40 ppm were prepared. Data obtained from eluted waters did not outweigh 1% of the TOG values of starting solutions. The kinetic study showed that the contaminant removal efficiency depends on the system elution flow rate; optimum removal values were reached at a 7.0 mL/min flow rate. High efficiency and speed in the purification process were obtained at this optimum flow rate. The passage of a water volume 1,000 times the volume of the column bed was not sufficient to observe its saturation level. (author)

  5. First Zenith Total Delay and Integrated Water Vapour Estimates from the Near Real-Time GNSS Data Processing Systems at the University of Luxembourg

    Science.gov (United States)

    Ahmed, F.; Teferle, F. N.; Bingley, R. M.

    2012-04-01

    Since September 2011 the University of Luxembourg in collaboration with the University of Nottingham has been setting up two near real-time processing systems for ground-based GNSS data for the provision of zenith total delay (ZTD) and integrated water vapour (IWV) estimates. Both systems are based on Bernese v5.0, use the double-differenced network processing strategy and operate with a 1-hour (NRT1h) and 15-minutes (NRT15m) update cycle. Furthermore, the systems follow the approach of the E-GVAP METO and IES2 systems in that the normal equations for the latest data are combined with those from the previous four updates during the estimation of the ZTDs. NRT1h currently takes the hourly data from over 130 GNSS stations in Europe whereas NRT15m is primarily using the real-time streams of EUREF-IP. Both networks include additional GNSS stations in Luxembourg, Belgium and France. The a priori station coordinates for all of these stem from a moving average computed over the last 20 to 50 days and are based on the precise point positioning processing strategy. In this study we present the first ZTD and IWV estimates obtained from the NRT1h and NRT15m systems in development at the University of Luxembourg. In a preliminary evaluation we compare their performance to the IES2 system at the University of Nottingham and find the IWV estimates to agree at the sub-millimetre level.

  6. Influence of enhanced fluid intake on reduction of committed dose after acute intake of tritiated water vapour by occupational workers at Narora Atomic Power Station, India

    International Nuclear Information System (INIS)

    Pawar, S.K.; Mitra, S.R.; Chand, Lal

    2001-01-01

    The study of acute exposure cases of male radiation workers to tritiated water vapour (HTO) in Narora Atomic Power Station, using the bi-exponential function has provided direct practical evidence that the committed dose following an HTO exposure is directly proportional to effective half-life which in turn is inversely proportional to the fluid intake. Urine samples from these workers apparently in good health, were collected and measured for tritium concentration in urine up to maximum of 163 days after the exposure. They were advised to increase their fluid intakes to accelerate the elimination of tritium for dose mitigation. Their fluid intakes reverted to normal levels in the later stage of the post exposure period. The non-linear regression analysis of the data of tritium concentration in urine showed an effective half-life of 1.5 to 3.8 days during the period of enhanced fluid intake, 3.4 to 6.9 days during the period of normal and slightly above normal fluid intake and 23.6 to 52.3 days due to elimination of metabolized organically bound tritium. This increase in elimination rate due to enhanced fluid intake directly resulted in dose mitigation of 45.1 to 76.0 percent in different subjects. (author)

  7. Surface fluxes of water vapour, momentum and CO{sub 2} over a savanna in Niger. A contribution to HAPEX-SAHEL

    Energy Technology Data Exchange (ETDEWEB)

    Verhoef, A; De Bruin, H A.R.; Krikke, R [Dept. of Meteorology. Landbouwuniversiteit, Wageningen (Netherlands)

    1995-11-01

    For large scale models such as Global Circulation Models (GCM) the lower boundary condition is often provided by a SVAT model (Soil-Vegetation-Atmosphere Transfer). A wide range of SVATs is in use nowadays, varying from models based on the simple big-leaf concept to complicated multiple source models. Obviously, a SVAT intended to provide the lower boundary condition in GCM`s needs to be able to describe a wide range of surface types, varying from completely vegetated to sparsely vegetated or completely bare surfaces. Especially sparse canopy surface types exhibit rather demanding features with respect to the exchange of momentum, water vapour, CO{sub 2} and heat between the surface and the atmosphere. In this paper attention is focused on a sparse canopy. We will compare SVAT model simulations with data collected in 1992 at a Savannah site, in the framework of the HAPEX-SAHEL project (a large-scale study of land atmosphere interactions in the semi-arid tropics). Two existing SVAT models are considered (Choudhury-Monteith and Deardorff). In a separate study these models have been tested. A combined model has been constructed, consisting of the `best` parts of the original SVAT`s. Some preliminary results will be presented. 4 figs., 14 refs., 1 appendix

  8. Arsenic removal from water using iron-coated seaweeds.

    Science.gov (United States)

    Vieira, Bárbara R C; Pintor, Ariana M A; Boaventura, Rui A R; Botelho, Cidália M S; Santos, Sílvia C R

    2017-05-01

    Arsenic is a semi-metal element that can enter in water bodies and drinking water supplies from natural deposits and from mining, industrial and agricultural practices. The aim of the present work was to propose an alternative process for removing As from water, based on adsorption on a brown seaweed (Sargassum muticum), after a simple and inexpensive treatment: coating with iron-oxy (hydroxides). Adsorption equilibrium and kinetics were studied and modeled in terms of As oxidation state (III and V), pH and initial adsorbate concentration. Maximum adsorption capacities of 4.2 mg/g and 7.3 mg/g were obtained at pH 7 and 20 °C for arsenite and arsenate, respectively. When arsenite was used as adsorbate, experimental evidences pointed to the occurrence of redox reactions involving As(III) oxidation to As(V) and Fe(III) reduction to Fe(II), with As(V) uptake by the adsorbent. The proposed adsorption mechanism was then based on the assumption that arsenate was the adsorbed arsenic species. The most relevant drawback found in the present work was the considerable leaching of iron to the solution. Arsenite removal from a mining-influenced water by adsorption plus precipitation was studied and compared to a traditional process of coagulation/flocculation. Both kinds of treatment provided practically 100% of arsenite removal from the contaminated water, leading at best in 12.9 μg/L As after the adsorption and precipitation assays and 14.2 μg/L after the coagulation/flocculation process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Carbon dioxide and water vapour exchange in a tropical dry forest as influenced by the North American Monsoon System (NAMS)

    Science.gov (United States)

    To better understand the effects and relationship between precipitation, net ecosystem carbon dioxide (NEE) and water vapor exchange (ET), we report a study conducted in the tropical dry forest (TDF) in the northwest of Mexico. Ecosystem gas exchange was measured using the eddy correlation technique...

  10. Drugs in Your Drinking Water: Removing Pharmaceutical Pollution

    Science.gov (United States)

    Richardson, K.

    2017-12-01

    Pharmaceuticals, mostly estrogen-based hormones and antibiotics, are increasingly polluting waterways and contaminating municipal drinking water sources. A 2008 study funded by the American Water Works Association Research Foundation and the WateReuse Foundation tested 19 drinking water treatment plants across the United States. The study found pharmaceuticals and metabolites at all of the locations tested. These plants provide drinking water for over 28 million Americans - yet only five states test for pharmaceuticals. A 2007 US Government Accountability Office study of male smallmouth bass showed ovarian tissue in their gonads and concluded the combination of EDCs (Endocrine Disrupting Chemicals) likely caused the feminization of the male fish. The purpose of this project is to determine whether bivalves can effectively remove pharmaceuticals as well as other CECs (Contaminants of Emerging Concern).Pharmaceuticals, specifically ibuprofen, were found to be resistant to chemical and mechanical filtration methods, such as coffee grounds and activated carbon, so biological filtration methods are used. Three types of common mollusks (Sphaeriidae `fingernail clams', freshwater mussels, scallops) will be used to assess the potential for biological remediation of the chemical pollutants. Fifteen specimens of each species will be used - a total of 45 individuals. Each group of five will be introduced to either an NSAID (ibuprofen), oil (vegetable) or hormone (estrogen, pending approval). This creates an array of 3 species and 3 contaminants, for a 3x3 grid of nine sample groups. Water is contaminated with pollutant levels similar to EPA measurements. The concentration will be measured before and after the introduction of the specimens using a UV spectrophotometer, at regular time intervals. As mollusks are capable of filtering up to two liters of water a day, the 37.8 liter tanks are filtered at a rate of 10 liters a day. A successful trial of bivalves reducing and

  11. Iron coated pottery granules for arsenic removal from drinking water.

    Science.gov (United States)

    Dong, Liangjie; Zinin, Pavel V; Cowen, James P; Ming, Li Chung

    2009-09-15

    A new media, iron coated pottery granules (ICPG) has been developed for As removal from drinking water. ICPG is a solid phase media that produces a stable Fe-Si surface complex for arsenic adsorption. Scanning electron microscopy (SEM) was used to document the physical attributes (grain size, pore size and distribution, surface roughness) of the ICPG media. Several advantages of the ICPG media such as (a) its granular structure, (b) its ability to absorb As via the F(0) coating on the granules' surface; (c) the inexpensive preparation process for the media from clay material make ICPG media a highly effective media for removing arsenic at normal pH. A column filtration test demonstrated that within the stability region (flow rate lower than 15L/h, EBCT >3 min), the concentration of As in the influent was always lower than 50 microg/L. The 2-week system ability test showed that the media consistently removed arsenic from test water to below the 5 microg/L level. The average removal efficiencies for total arsenic, As(III), and As(V) for a 2-week test period were 98%, 97%, and 99%, respectively, at an average flow rate of 4.1L/h and normal pH. Measurements of the Freundlich and Langmuir isotherms at normal pH show that the Freundlich constants of the ICPG are very close to those of ferric hydroxide, nanoscale zero-valent iron and much higher than those of nanocrystalline titanium dioxide. The parameter 1/n is smaller than 0.55 indicating a favorable adsorption process [K. Hristovski, A. Baumgardner, P. Westerhoff, Selecting metal oxide nanomaterials for arsenic removal in fixed bed columns: from nanopowders to aggregated nanoparticle media, J. Hazard. Mater. 147 (2007) 265-274]. The maximum adsorption capacity (q(e)) of the ICPG from the Langmuir isotherm is very close to that of nanoscale zero-valent indicating that zero-valent iron is involved in the process of the As removal from the water. The results of the toxicity characteristic leaching procedure (TCLP

  12. Iron coated pottery granules for arsenic removal from drinking water

    International Nuclear Information System (INIS)

    Dong Liangjie; Zinin, Pavel V.; Cowen, James P.; Ming, Li Chung

    2009-01-01

    A new media, iron coated pottery granules (ICPG) has been developed for As removal from drinking water. ICPG is a solid phase media that produces a stable Fe-Si surface complex for arsenic adsorption. Scanning electron microscopy (SEM) was used to document the physical attributes (grain size, pore size and distribution, surface roughness) of the ICPG media. Several advantages of the ICPG media such as (a) its granular structure, (b) its ability to absorb As via the F(0) coating on the granules' surface; (c) the inexpensive preparation process for the media from clay material make ICPG media a highly effective media for removing arsenic at normal pH. A column filtration test demonstrated that within the stability region (flow rate lower than 15 L/h, EBCT >3 min), the concentration of As in the influent was always lower than 50 μg/L. The 2-week system ability test showed that the media consistently removed arsenic from test water to below the 5 μg/L level. The average removal efficiencies for total arsenic, As(III), and As(V) for a 2-week test period were 98%, 97%, and 99%, respectively, at an average flow rate of 4.1 L/h and normal pH. Measurements of the Freundlich and Langmuir isotherms at normal pH show that the Freundlich constants of the ICPG are very close to those of ferric hydroxide, nanoscale zero-valent iron and much higher than those of nanocrystalline titanium dioxide. The parameter 1/n is smaller than 0.55 indicating a favorable adsorption process [K. Hristovski, A. Baumgardner, P. Westerhoff, Selecting metal oxide nanomaterials for arsenic removal in fixed bed columns: from nanopowders to aggregated nanoparticle media, J. Hazard. Mater. 147 (2007) 265-274]. The maximum adsorption capacity (q e ) of the ICPG from the Langmuir isotherm is very close to that of nanoscale zero-valent indicating that zero-valent iron is involved in the process of the As removal from the water. The results of the toxicity characteristic leaching procedure (TCLP) analysis

  13. Water hyacinths and alligator weeds for removal of silver, cobalt, and strontium from polluted waters

    Science.gov (United States)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Water hyacinths and alligator weeds demonstrated the ability to rapidly remove heavy metals from an aqueous system by root absorption and concentration. Water hyacinths demonstrated the ability to remove 0.439 mg of silver, 0.568 mg of cobalt, and 0.544 mg of strontium in an ionized form per gram of dry plant material in a 24-hour period. Alligator weeds removed a maximum of 0.439 mg of silver, 0.130 mg of cobalt, and 0.161 mg of strontium per gram of dry plant material per day.

  14. Diclofenac removal from water with ozone and activated carbon.

    Science.gov (United States)

    Beltrán, Fernando J; Pocostales, Pablo; Alvarez, Pedro; Oropesa, Ana

    2009-04-30

    Diclofenac (DCF) has been treated in water with ozone in the presence of various activated carbons. Activated carbon-free ozonation or single ozonation leads to a complete degradation of DCF in less than 15 min while in the presence of activated carbons higher degradation rates of TOC and DCF are noticeably achieved. Among the activated carbons used, P110 Hydraffin was found the most suitable for the catalytic ozonation of DCF. The influence of pH was also investigated. In the case of the single ozonation the increasing pH slightly increases the TOC removal rate. This effect, however, was not so clear in the presence of activated carbons where the influence of the adsorption process must be considered. Ecotoxicity experiments were performed, pointing out that single ozonation reduces the toxicity of the contaminated water but catalytic ozonation improved those results. As far as kinetics is concerned, DCF is removed with ozone in a fast kinetic regime and activated carbon merely acts as a simple adsorbent. However, for TOC removal the ozonation kinetic regime becomes slow. In the absence of the adsorbent, the apparent rate constant of the mineralization process was determined at different pH values. On the other hand, determination of the rate constant of the catalytic reaction over the activated carbon was not possible due to the effect of mass transfer resistances that controlled the process rate at the conditions investigated.

  15. Mean ozone and water vapour height profiles for Southern hemisphere region using radiosonde or ozonesonde and haloe satelite data

    CSIR Research Space (South Africa)

    Sivakumar, V

    2009-01-01

    Full Text Available obtained from HALOE datasets 6 3.3. SHADOZ mean Ozone The mean ozone obtained from SHADOZ ozonesonde insitu measurement; from Nairobi located at 1.27°S and 36.8°E, Malindi at 2.99°S and 40.2°E and Irene at 25.9°S and 28.22°E, stations are displayed... - 2090. 8 2. Lohmann, M.S., et al., Water vapor profile using LEO - LEO Intersatellite Links. Danish Metereological Institute. Atmospheric Ionosphere Research. 3. Jones, R.L. and Mitchell,J.F.B., (1991) Climate change - is water vapor...

  16. Influence of low water-vapour concentrations in air and carbon dioxide on the inflammability of magnesium in these media

    International Nuclear Information System (INIS)

    Darras, Raymond; Baque, Pierre; Leclercq, Daniel

    1960-01-01

    The temperatures at which live combustion starts in magnesium and certain of its alloys have been determined systematically in air and in carbon dioxide. In carbon dioxide, the ignition temperature is reduced by 130 to 140 deg. C for very low water-vapor concentrations. Reprint of a paper published in 'Comptes Rendus des Seances de l'Academie des Sciences', tome 240, p. 1647-1649, sitting of 28 October 1959 [fr

  17. Atomic layer deposition of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/TiO{sub 2} barrier coatings to reduce the water vapour permeability of polyetheretherketone

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadzada, Tamkin, E-mail: tahm4852@uni.sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); McKenzie, David R.; James, Natalie L.; Yin, Yongbai [School of Physics, University of Sydney, NSW 2006 (Australia); Li, Qing [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia)

    2015-09-30

    We demonstrate significantly enhanced barrier properties of polyetheretherketone (PEEK) against water vapour penetration by depositing Al{sub 2}O{sub 3} or Al{sub 2}O{sub 3}/TiO{sub 2} nanofilms grown by atomic layer deposition (ALD). Nanoindentation analysis revealed good adhesion strength of a bilayer Al{sub 2}O{sub 3}/TiO{sub 2} coating to PEEK, while the single layer Al{sub 2}O{sub 3} coating displayed flaking and delamination. We identified three critical design parameters for achieving the optimum barrier properties of ALD Al{sub 2}O{sub 3}/TiO{sub 2} coatings on PEEK. These are a minimum total thickness dependent on the required water vapour transmission rate, the use of an Al{sub 2}O{sub 3}/TiO{sub 2} bilayer coating and the application of the coating to both sides of the PEEK film. Using these design parameters, we achieved a reduction in moisture permeability of PEEK of over two orders of magnitude while maintaining good adhesion strength of the polymer–thin film system. - Highlights: • Atomic layer deposition of Al{sub 2}O{sub 3}/TiO{sub 2} coatings reduced water vapour permeability. • Bilayer coatings reduced the permeability more than single layer coatings. • Bilayer coatings displayed higher adhesion strength than the single layer coatings. • Double-sided coatings performed better than single-sided coatings. • Correlation was found between total thickness and reduced water vapour permeability.

  18. Emission, absorption and group delay of microwaves in the atmosphere in relation to water vapour content over the Indian subcontinent

    Science.gov (United States)

    Sen, A. K.; Gupta, A. K. D.; Karmakar, P. K.; Barman, S. D.; Bhattacharya, A. B.; Purkait, N.; Gupta, M. K. D.; Sehra, J. S.

    1985-01-01

    The advent of satellite communication for global coverage has apparently indicated a renewed interest in the studies of radio wave propagation through the atmosphere, in the VHF, UHF and microwave bands. The extensive measurements of atmosphere constituents, dynamics and radio meterological parameters during the Middle Atmosphere Program (MAP) have opened up further the possibilities of studying tropospheric radio wave propagation parameters, relevant to Earth/space link design. The three basic parameters of significance to radio propagation are thermal emission, absorption and group delay of the atmosphere, all of which are controlled largely by the water vapor content in the atmosphere, particular at microwave bands. As good emitters are also good absorbers, the atmospheric emission as well as the absorption attains a maximum at the frequency of 22.235 GHz, which is the peak of the water vapor line. The group delay is practically independent of frequency in the VHF, UHF and microwave bands. However, all three parameters exhibit a similar seasonal dependence originating presumably from the seasonal dependence of the water vapor content. Some of the interesting results obtained from analyses of radiosonde data over the Indian subcontinent collected by the India Meteorological Department is presented.

  19. Removal of emerging micropollutants from water using cyclodextrin.

    Science.gov (United States)

    Nagy, Zsuzsanna Magdolna; Molnár, Mónika; Fekete-Kertész, Ildikó; Molnár-Perl, Ibolya; Fenyvesi, Éva; Gruiz, Katalin

    2014-07-01

    Small scale laboratory experiment series were performed to study the suitability of a cyclodextrin-based sorbent (ß-cyclodextrin bead polymer, BCDP) for modelling the removal of micropollutants from drinking water and purified waste water using simulated inflow test solutions containing target analytes (ibuprofen, naproxen, ketoprofen, bisphenol-A, diclofenac, β-estradiol, ethinylestradiol, estriol, cholesterol at 2-6 μg/L level). This work was focused on the preliminary evaluation of BCDP as a sorbent in two different model systems (filtration and fluidization) applied for risk reduction of emerging micropollutants. For comparison different filter systems combined with various sorbents (commercial filter and activated carbon) were applied and evaluated in the filtration experiment series. The spiked test solution (inflow) and the treated outflows were characterized by an integrated methodology including chemical analytical methods gas chromatography-tandem mass spectrometry (GC-MS/MS) and various environmental toxicity tests to determine the efficiency and selectivity of the applied sorbents. Under experimental conditions the cyclodextrin-based filters used for purification of drinking water in most cases were able to absorb more than 90% of the bisphenol-A and of the estrogenic compounds. Both the analytical chemistry and toxicity results showed efficient elimination of these pollutants. Especially the toxicity of the filtrate decreased considerably. Laboratory experiment modelling post-purification of waste water was also performed applying fluidization technology by ß-cyclodextrin bead polymer. The BCDP removed efficiently from the spiked test solution most of the micropollutants, especially the bisphenol-A (94%) and the hormones (87-99%) The results confirmed that the BCDP-containing sorbents provide a good solution to water quality problems and they are able to decrease the load and risk posed by micropollutants to the water systems. Copyright © 2014

  20. Point-of-entry removal of radon from drinking water

    International Nuclear Information System (INIS)

    Lowry, J.D.; Brutsaert, W.F.; Mc Enerney, T.; Molk, C.

    1987-01-01

    Two processes were investigated in the laboratory to determine their efficiency for removing radon from household water supplies. Granular activated carbon (GAC) adsorption was found to be extremely effective as a result of an adsorption-decay steady state that is established quickly and continues for years. The GAC bed, however, adsorbs radon progeny as the radon decays, and it becomes a source of gamma radiation. This problem is believed to be manageable for the vast majority of potential applications. Diffused bubble aeration was found to be as effective as GAC, with removals of greater than 99 percent being practical. Although more costly than GAC, aeration does not have the problem of gamma activity buildup

  1. Modeling of the Process of Three-Isotope (H, D, T) Exchange Between Hydrogen Gas and Water Vapour on Pt-SDBC Catalyst over a Wide Range of Deuterium Concentration

    International Nuclear Information System (INIS)

    Fedorchenko, O.A.; Alekseev, I.A.; Tchijov, A.S.; Uborsky, V.V.

    2005-01-01

    The large scale studies of Combined Electrolysis and Catalytic Exchange (CECE) process in Petersburg Nuclear Physics Institute showed a complicated influence of various factors on the process caused by the presence of two simultaneous isotope exchange sub processes: counter-current phase exchange (between liquid water and water vapour) and co-current catalytic exchange (between hydrogen gas and water vapour). A laboratory scale set-up of glass made apparatuses was established in such a way that it allows us to study phase and catalytic exchange apart. A computer model of the set-up has been developed.The catalytic isotope exchange model formulation is presented. A collection of reversible chemical reactions is accompanied by diffusion of the gaseous reactants and reaction products in the pores of catalyst carrier. This has some interesting features that are demonstrated. Thus it was noted that the flow rates ratio (gas to vapour - λ = G/V) as well as the concentrations of reactants exert influence on the process efficiency

  2. Evaluation of a dimension-reduction-based statistical technique for Temperature, Water Vapour and Ozone retrievals from IASI radiances

    Science.gov (United States)

    Amato, Umberto; Antoniadis, Anestis; De Feis, Italia; Masiello, Guido; Matricardi, Marco; Serio, Carmine

    2009-03-01

    Remote sensing of atmosphere is changing rapidly thanks to the development of high spectral resolution infrared space-borne sensors. The aim is to provide more and more accurate information on the lower atmosphere, as requested by the World Meteorological Organization (WMO), to improve reliability and time span of weather forecasts plus Earth's monitoring. In this paper we show the results we have obtained on a set of Infrared Atmospheric Sounding Interferometer (IASI) observations using a new statistical strategy based on dimension reduction. Retrievals have been compared to time-space colocated ECMWF analysis for temperature, water vapor and ozone.

  3. Removal of Arsenic from Drinking Water Using Modified Activated Alumina

    Directory of Open Access Journals (Sweden)

    Mohammad Mosaferi

    2005-09-01

    Full Text Available Considering contamination of drinking water to arsenic in some villages ofIran. In order to develop a simple method for household water treatment in rural areas, efficiency of  modified activated alumina with iron compounds- a product of Alcan Company with trade name of AAFS-50- was studied Equilibrium batch experiments were carried out using shaker incubator and arsenic was analyzed with SDDC method. Effects of initial concentration of arsenic, adsorbent dose, oxidation state of arsenic, pH and oxidation with chlorine on adsorption were studied. Correlation coefficient of Freundlich and Laungmuier  isotherms  for As(V and As(III were 0.964 , 0.991 and 0.970, 0.978 respectively . These results show that adsorption of arsenic on modified activated alumina is compatible with both models specially Laungmuier models. Removal efficiency of As(V at 0.5 ,1 and 2 hr increased with doubling the adsorbent dose from 44.8 to 72%, 69.6 to 90.8 and 92.4 to 98% ; respectively. Experiments using different concentrations of arsenic showed that adsorption of arsenic on activated alumina are a first order reaction that is, rate of reaction is dependent on intial; concentration of arsenic. Removal efficiency for concentration of 0.250 mg/L of arsenic, with increasing of reaction time from 15 min to 60 min, increased 1.54 times and reached from 61% to 94%. During 2hrs, removal of As(V and As(III were 96% and 16% respectively. Using 1.5 mg/L Chlorine as oxidant agent, removal of As(III was increased to 94%. In the case of pH effect, rate of adsorption increased for arsenite, with increasing of pH to 8 and decreased with more increasing, so that adsorption at pH 14 was equal to pH 2. For arsenate, the most adsorption was observed at pH between 6 to 8 . These results show that by using the studied activated alumina, there will not be need for adjustment of pH and the activated alumina used in this study could have application as a safe adsorbent for removal of

  4. REMOVING AGGRESSIVE CARBON DIOXIDE FROM WATER USING MELAPHYRE BED

    Directory of Open Access Journals (Sweden)

    Magdalena Maria Michel

    2017-09-01

    Full Text Available The experiment was based on filtration of the highly aggressive water through the melaphyre bed. The quartz bed was non-reactive reference material. The aim of this work was to determine the ability of the melaphyre to remove aggressive CO2 during the chemical reaction. It was noted that a decrease of acidity of the filtrate in comparison to the feed and an increase of its alkalinity and pH. It was calculated that until the moment of exhaustion of the de-acidifying properties of the melaphyre, maximum amount of bound CO2 added to the water was 29.7 g CO2/L of the bed, and maximum amount of the aggressive CO2 removed from the water was 33.3 g CO2/L of the bed. Regarding very high content of the aggressive CO2 (116 mg/L average in the feed only 28.76% of this component was subject to transformation into bound and affiliated CO2 in the filtrate. For the melaphyre bed the CO2 loss from the experiment system following from desorption was 7.80% of the total load of CO2 added with the feed. On the quartz bed the loss was slightly lower 4.56%.

  5. REMOVAL OF ARSENIC IN DRINKING WATER: ARS CFU-50 APC ELECTROFLOCCULATION AND FILTRATION WATER TREATMENT SYSTEM

    Science.gov (United States)

    ETV testing of the ARS CFU-50 APC Electroflocculation and Filtration Water Treatment System (ARS CFU-50 APC) for arsenic removal was conducted at the Town of Bernalillo Well #3 site from April 18 through May 2, 2006. The source water was chlorinated groundwater from two supply w...

  6. The use of a heat transfer coefficient for describing the radiative exchange between water vapour and the bounding walls

    International Nuclear Information System (INIS)

    Eifler, W.; Shepherd, I.M.

    1983-01-01

    During the ''severe-fuel-damage'' experiments of the SUPER SARA test program radiation heat transfer will play an important part. For the analysis of these experiments it should be modelled therefore in a particularly appropriate manner. Based on the same engineering type principles which are used in the radiation model of the TRAC code version for boiling water reactors a new model has been developed. This model is less computer time consuming than the TRAC model and particularly appropriate for the use in the subchannel - type bundle computer code which is planned to be developed for the analysis of the ''severe-fuel-damage'' experiments. Sample calculations for the ''severe-fuel-damage'' test array show that the difference between the results obtained with the new model and those obtained with the TRAC model is in general not significant

  7. An unstructured finite volume solver for two phase water/vapour flows based on an elliptic oriented fractional step method

    International Nuclear Information System (INIS)

    Mechitoua, N.; Boucker, M.; Lavieville, J.; Pigny, S.; Serre, G.

    2003-01-01

    Based on experience gained at EDF and Cea, a more general and robust 3-dimensional (3D) multiphase flow solver has been being currently developed for over three years. This solver, based on an elliptic oriented fractional step approach, is able to simulate multicomponent/multiphase flows. Discretization follows a 3D full unstructured finite volume approach, with a collocated arrangement of all variables. The non linear behaviour between pressure and volume fractions and a symmetric treatment of all fields are taken into account in the iterative procedure, within the time step. It greatly enforces the realizability of volume fractions (i.e 0 < α < 1), without artificial numerical needs. Applications to widespread test cases as static sedimentation, water hammer and phase separation are shown to assess the accuracy and the robustness of the flow solver in different flow conditions, encountered in nuclear reactors pipes. (authors)

  8. Effects of water chemistry on arsenic removal from drinking water by electrocoagulation.

    Science.gov (United States)

    Wan, Wei; Pepping, Troy J; Banerji, Tuhin; Chaudhari, Sanjeev; Giammar, Daniel E

    2011-01-01

    Exposure to arsenic through drinking water poses a threat to human health. Electrocoagulation is a water treatment technology that involves electrolytic oxidation of anode materials and in-situ generation of coagulant. The electrochemical generation of coagulant is an alternative to using chemical coagulants, and the process can also oxidize As(III) to As(V). Batch electrocoagulation experiments were performed in the laboratory using iron electrodes. The experiments quantified the effects of pH, initial arsenic concentration and oxidation state, and concentrations of dissolved phosphate, silica and sulfate on the rate and extent of arsenic removal. The iron generated during electrocoagulation precipitated as lepidocrocite (γ-FeOOH), except when dissolved silica was present, and arsenic was removed by adsorption to the lepidocrocite. Arsenic removal was slower at higher pH. When solutions initially contained As(III), a portion of the As(III) was oxidized to As(V) during electrocoagulation. As(V) removal was faster than As(III) removal. The presence of 1 and 4 mg/L phosphate inhibited arsenic removal, while the presence of 5 and 20 mg/L silica or 10 and 50 mg/L sulfate had no significant effect on arsenic removal. For most conditions examined in this study, over 99.9% arsenic removal efficiency was achieved. Electrocoagulation was also highly effective at removing arsenic from drinking water in field trials conducted in a village in Eastern India. By using operation times long enough to produce sufficient iron oxide for removal of both phosphate and arsenate, the performance of the systems in field trials was not inhibited by high phosphate concentrations. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Coagulation chemistries for silica removal from cooling tower water.

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

    2010-02-01

    The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

  10. Community Responses to the Removal of Bottled Water on a University Campus

    Science.gov (United States)

    Mikhailovich, Katja; Fitzgerald, Robert

    2014-01-01

    Purpose: This paper aimed to examine the impact of the removal of bottled water on the campus community. This paper presents the findings of a survey conducted at the first Australian university to remove single-use bottled water from sale on a small regional university campus. The removal of bottled water from sale at the university formed part…

  11. Removal of fluoride from water using aluminium containing compounds

    Institute of Scientific and Technical Information of China (English)

    M. Karthikeyan; K. P. Elango

    2009-01-01

    Batch adsorption studies were undertaken to assess the suitability of aluminium titanate (AT) and bismuth aluminate (BA) to remove fluoride ions from water.The effect of pH,dose of adsorbent,contact time,initial concentration,co-ions and temperature on fluoride removal efficiency were studied.The amounts of fluoride ions adsorbed,at 30℃ from 4 mg/L of fluoride ion solution,by AT and BA are 0.85 and 1.55 mg/g,respectively.The experimental data fitted well to the Freundlich and Langmuir isotherms.Thermodynamic parameters such as △H~0,△S~0 and △G~0 indicated that the removal of fluoride ions by AT is exothermic and non-spontaneous while that by BA is endothermic and spontaneous.Furrier transform infrared (FT-IR) analysis and X-ray diffraction (XRD) patterns of the adsorbent before and after adsorption indicated that fluoride ions are chemisorbed by these adsorbents.

  12. Removal of Foodborne Pathogen Biofilms by Acidic Electrolyzed Water

    Directory of Open Access Journals (Sweden)

    Qiao Han

    2017-06-01

    Full Text Available Biofilms, which are complex microbial communities embedded in the protective extracellular polymeric substances (EPS, are difficult to remove in food production facilities. In this study, the use of acidic electrolyzed water (AEW to remove foodborne pathogen biofilms was evaluated. We used a green fluorescent protein-tagged Escherichia coli for monitoring the efficiency of AEW for removing biofilms, where under the optimal treatment conditions, the fluorescent signal of cells in the biofilm disappeared rapidly and the population of biofilm cells was reduced by more than 67%. Additionally, AEW triggered EPS disruption, as indicated by the deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the amino acids tyrosine and phenylalanine. These deformations were identified by EPS chemical analysis and Raman spectroscopic analysis. Scanning electron microscopy (SEM images confirmed that the breakup and detachment of biofilm were enhanced after AEW treatment. Further, AEW also eradicated biofilms formed by both Gram-negative bacteria (Vibrio parahaemolyticus and Gram-positive bacteria (Listeria monocytogenes and was observed to inactivate the detached cells which are a potential source of secondary pollution. This study demonstrates that AEW could be a reliable foodborne pathogen biofilm disrupter and an eco-friendly alternative to sanitizers traditionally used in the food industry.

  13. Detection of polar vapours

    International Nuclear Information System (INIS)

    Blyth, D.A.

    1980-01-01

    Apparatus for monitoring for polar vapours in a gas consists of (i) a body member defining a passage through which a continuous stream of the gas passes; (ii) an ionising source associated with a region of the passage such that ionization of the gas stream takes place substantially only within the region and also any polar vapour molecules present therein will react with the gas formed to generate ion clusters; and (iii) an electrode for collecting ions carried by the gas stream, the electrode being positioned in the passage downstream of the region and separated from the region by a sufficient distance to ensure that no substantial number of the gas ions formed in said region remains in the gas stream at the collector electrode whilst ensuring that a substantial proportion of the ion clusters formed in the region does remain in the gas stream at the collector electrode. (author)

  14. Role of water in the tribochemical removal of bare silicon

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cheng; Xiao, Chen [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Xiaodong [Center of Micro/Nano Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Zhang, Peng; Chen, Lei; Qi, Yaqiong [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Qian, Linmao, E-mail: linmao@swjtu.edu.cn [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-12-30

    Highlights: • The wear of bare silicon against SiO{sub 2} micro-spherical tip is a tribochemical process with participation of water. • The water amount at Si/SiO{sub 2} interface plays a significant role on the wear of bare silicon. • The role of water relies on the hydroxylation by auto-ionized OH{sup −}, the hydrolysis of H{sub 2}O molecules, and the dissolution of SiO{sub m}H{sub n} in water. - Abstract: Nanowear tests of bare silicon against a SiO{sub 2} microsphere were conducted in air (relative humidity [RH] = 0%–89%) and water using an atomic force microscope. Experimental results revealed that the water played an important role in the tribochemical wear of the bare silicon. A hillock-like wear trace with a height of 0.7 nm was generated on the bare silicon surface in dry air. As the RH increased, the wear depth increased and reached the maximum level in water. Analysis of frictional dissipated energy suggested that the wear of the bare silicon was not dominated by mechanical interactions. High-resolution transmission electron microscopy detection demonstrated that the silicon atoms and crystal lattice underneath the worn area maintained integral perfectly and thus further confirmed the tribochemical wear mechanism of the bare silicon. Finally, the role of water in the tribochemical wear of the bare silicon may be explained by the following three aspects: the hydroxylation by hydroxyl ions auto-ionized in water, the hydrolytic reaction of water molecules, and the dissolution of the tribochemical product SiO{sub m}H{sub n} in liquid water. With increasing RH, a greater water amount would adsorb to the Si/SiO{sub 2} interface and induce a more serious tribochemical wear on the bare silicon surface. The results of this paper may provide further insight into the tribochemical removal mechanism of bare monocrystalline silicon and furnish the wider reaction cognition for chemical mechanical polishing.

  15. A biosystem for removal of metal ions from water

    Energy Technology Data Exchange (ETDEWEB)

    Kilbane, J.J. II.

    1990-01-01

    The presence of heavy metal ions in ground and surface waters constitutes a potential health risk and is an environmental concern. Moreover, processes for the recovery of valuable metal ions are of interest. Bioaccumulation or biosorption is not only a factor in assessing the environmental risk posed by metal ions; it can also be used as a means of decontamination. A biological system for the removal and recovery of metal ions from contaminated water is reported here. Exopolysaccharide-producing microorganisms, including a methanotrophic culture, are demonstrated to have superior metal binding ability, compared with other microbial cultures. This paper describes a biosorption process in which dried biomass obtained from exopolysaccharide-producing microorganisms is encapsulated in porous plastic beads and is used for metal ion binding and recovery. 22 refs., 13 figs.

  16. Removal of chlorinated ethylenes from drinking water by radiation treatments

    International Nuclear Information System (INIS)

    Gehringer, P.; Proksch, E.; Eschweiler, H.; Szinovatz, W.

    1990-01-01

    Per- and trichloroethylene dissolved in sub-ppm amounts in Vienna City drinking water are decomposed under γ-irradiations according to first-order rate laws. Doses D 90 necessary for a 90% pollutant removal are 255 Gy (perchloroethylene) and 120 Gy (trichloroethylene). For other waters D 90 values increase with increasing concentration of organic and inorganic solutes present, especially of bicarbonate. Main decomposition products are Cl - , CO 2 and (for trichloroethylene only) HCOOH. The additional presence of 0.5 to 10 ppm ozone decreases the D 90 values by factors up to ten; they can be as low as 33 Gy (perchloroethylene) or even 12 Gy (trichloroethylene). The rate laws, however, are no longer of first, but of higher order. (author)

  17. Removing NDMA (N,N-dimethylnitrosamine) from natural waters

    International Nuclear Information System (INIS)

    Mezyk, S.P.; Cooper, W.J.; Bartels, D.M.

    2003-01-01

    Nitrosoamines are ubiquitous in water environments, and are of concern as they are potent carcinogens. In particular, N,N-dimethylnitrosamine (NDMA, (CH 3 ) 2 NNO) is volatile, and therefore has been detected around factories producing secondary amines or rocket fuel, in areas near industrial plants that use dimethylamine in organic synthesis, and even in foods and beverages that contain nitrite or which have been exposed to nitrous oxides. Various technologies have been suggested for removing trace levels of NDMA contamination from aqueous systems. However, Advanced Oxidation Technologies (AOTs), such as ozone, UV/ozone, and UV/H 2 O 2 , which use oxidation via the hydroxyl radical ( . OH), or heterogeneous catalysis by TiO 2 , sonolysis, or the electron beam process, which produce a mixture of oxidizing . OH radicals with reducing hydrated electrons (e - aq ) and hydrogen atoms ( . H), may also produce unwanted stable products in the treatment. Some of these stable products, such as secondary amines, allow regeneration of NDMA to occur. To ensure that any process applied to NDMA contaminated water occurs efficiently and quantitatively a complete understanding of the chemistry involved under the conditions of use is necessary. This requires mathematical modeling of the process, which in turn needs reaction rate constants and mechanisms. In this study, absolute rate constants at room temperature for the reaction of the hydroxyl radical, hydrated electron, and hydrogen atom with NDMA in water have been determined using electron pulse radiolysis and absorption spectroscopy, (e - aq and . OH) and EPR free induction decay attenuation ( . H) measurements. The specific values of (4.30± 0.12) x 10 8 , (1.41 ± 0.02) x 10 10 , and (2.01 ± 0.03) x 10 8 M -1 s -1 , respectively, demonstrate that the reductive destruction of this nitrosoamine would be the dominant removal pathway in any remediation process. Based on these data we have begun modeling the large-scale electron

  18. Iron oxide hydroxide nanoflower assisted removal of arsenic from water

    Energy Technology Data Exchange (ETDEWEB)

    Raul, Prasanta Kumar, E-mail: prasanta.drdo@gmail.com [Defence Research Laboratory, Post Bag No. 2, Tezpur 784001, Assam (India); Devi, Rashmi Rekha; Umlong, Iohborlang M. [Defence Research Laboratory, Post Bag No. 2, Tezpur 784001, Assam (India); Thakur, Ashim Jyoti [Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784028, Assam (India); Banerjee, Saumen; Veer, Vijay [Defence Research Laboratory, Post Bag No. 2, Tezpur 784001, Assam (India)

    2014-01-01

    Graphical abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. TEM image clearly reveals that the nanoparticle looks flower like morphology with average particle size less than 20 nm. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature and the data fitted to different isotherm models indicate the heterogeneity of the adsorbent surface. The material can be regenerated up to 70% using dilute hydrochloric acid and it would be utilized for de-arsenification purposes. - Highlights: • The work includes synthesis of iron oxide hydroxide nanoflower and its applicability for the removal of arsenic from water. • The nanoparticle was characterized using modern instrumental methods like FESEM, TEM, BET, XRD, etc. • The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature. • The sorption is multilayered on the heterogeneous surface of the nano adsorbent. • The mechanism of arsenic removal of IOH nanoflower follows both adsorption and ion-exchange. - Abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. The nanoparticle was characterized by X-ray powder diffraction analysis (XRD), BET surface area, FTIR, FESEM and TEM images. TEM image clearly reveals flower like morphology with average particle size less than 20 nm. The nanoflower morphology is also supported by FESEM images. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic and the data fitted to different isotherm models indicate the

  19. Vapour pressure of trideuterioammonia

    Energy Technology Data Exchange (ETDEWEB)

    Calado, J.C.G.; Lopes, J.N.C.; Rebelo, L.P.N. (Instituto Superior Tecnico, Lisbon (Portugal). Centro de Quimica Estrutural)

    1992-09-01

    The H-to-D vapour-pressure isotope effect in liquid ammonia has been measured at 62 temperatures between 228 K and 260 K. The vapour pressures, corrected to 100 per cent nuclidic purity, have been fitted to the equation: T ln r = A+B/T+CT, where r is the vapour-pressure ratio p(NH[sub 3])/p(ND[sub 3]). The fit yielded the parameters: A = -8.22508 K, B = 12338.2 K[sup 2], and C = -0.05544. Comparisons with the results of other authors were made in order to clarify some discrepancies found in the literature. Our values are in accord with the previous results of King et al. and an extrapolation of the fitted equation down to the triple-point temperature gave good agreement with the published results. The fitted equation was used in conjunction with the Clapeyron equation to calculate the difference in the molar enthalpies of vaporization between NH[sub 3] and ND[sub 3]. At T = 230 K that difference is -846 J.mol[sup -1] decreasing to -747 J.mol[sup -1] at 260 K. (author).

  20. Removal of toxic chemicals from water with activated carbon

    Science.gov (United States)

    Dawson, V.K.; Marking, L.L.; Bills, T.D.

    1976-01-01

    Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, NoxfishA? (5% rotenone), Dibrorms, juglone, MSa??222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths of 15, 30, and 60 cm; temperatures of 7, 12, 17, and 22 C; pH's of 6.5, 7.5, 8.5, and 9.5; and flow rates of 50, 78, 100, 200, and 940 ml/min. Adsorptive capacity increased when the contact time was increased by reducing the flow rate or increasing the column depth. The adsorptive capacity was not significantly influenced by temperature but was substantially higher at pH 6.5 than at the other pH's tested. A practical and efficient filter for purifying chemically treated water was developed.

  1. Removal of Metal Nanoparticles Colloidal Solutions by Water Plants

    Science.gov (United States)

    Olkhovych, Olga; Svietlova, Nataliia; Konotop, Yevheniia; Karaushu, Olena; Hrechishkina, Svitlana

    2016-11-01

    The ability of seven species of aquatic plants ( Elodea canadensis, Najas guadelupensis, Vallisneria spiralis L., Riccia fluitans L., Limnobium laevigatum, Pistia stratiotes L., and Salvinia natans L.) to absorb metal nanoparticles from colloidal solutions was studied. It was established that investigated aquatic plants have a high capacity for removal of metal nanoparticles from aqueous solution (30-100%) which indicates their high phytoremediation potential. Analysis of the water samples content for elements including the mixture of colloidal solutions of metal nanoparticles (Mn, Cu, Zn, Ag + Ag2O) before and after exposure to plants showed no significant differences when using submerged or free-floating hydrophytes so-called pleuston. However, it was found that the presence of submerged hydrophytes in aqueous medium ( E. canadensis, N. guadelupensis, V. spiralis L., and R. fluitans L.) and significant changes in the content of photosynthetic pigments, unlike free-floating hydrophytes ( L. laevigatum, P. stratiotes L., S. natans L.), had occur. Pleuston possesses higher potential for phytoremediation of contaminated water basins polluted by metal nanoparticles. In terms of removal of nanoparticles among studied free-floating hydrophytes, P. stratiotes L. and S. natans L. deserve on special attention.

  2. Inorganic arsenic removal in rice bran by percolating cooking water.

    Science.gov (United States)

    Signes-Pastor, Antonio J; Carey, Manus; Meharg, Andrew A

    2017-11-01

    Rice bran, a by-product of milling rice, is highly nutritious but contains very high levels of the non-threshold carcinogen inorganic arsenic (i-As), at concentrations around 1mg/kg. This i-As content needs to be reduced to make rice bran a useful food ingredient. Evaluated here is a novel approach to minimizing rice bran i-As content which is also suitable for its stabilization namely, cooking bran in percolating arsenic-free boiling water. Up to 96% of i-As removal was observed for a range of rice bran products, with i-As removal related to the volume of cooking water used. This process reduced the copper, potassium, and phosphorus content, but had little effect on other trace- and macro-nutrient elements in the rice bran. There was little change in organic composition, as assayed by NIR, except for a decrease in the soluble sugar and an increase, due to biomass loss, in dietary fiber. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. APPLICATION OF POWDERY ACTIVATED CARBONS FOR REMOVAL IBUPROFEN FROM WATER

    Directory of Open Access Journals (Sweden)

    Alicja Puszkarewicz

    2017-07-01

    Full Text Available The paper presents results of studies on the use of adsorptive properties of selected powdered activated carbons (Norit SA Super and Carbopol MB5 for removal of ibuprofen from water. The tests were performed on non-flow conditions, series depending on the type and dose of powdered adsorbents. The research was carried out on a model solution of ibuprofen at initial concentration C0 = 20 mg/dm3, at 200 C. Froundlich and Langmuir adsorption isotherms were used. Lagergrene kinetic models (PFO and Ho (PSO were used to describe adsorption kinetics. Both carbons exhibited a higher affinity for the adsorbent at a pH above 7. The better adsorbent was the Norit SA Super, for which, the highest adsorption capacity q = 0.448 g/g was achieved with dose D = 35 mg/dm3. The effectiveness of adsorption (decrease of ibuprofen in water was 78%. Total removal of ibuprofen was obtained for a dose of carbon D = 200 mg/dm3. With respect to Carbopol, the highest adsorption capacity (q = 0.353 g / g was achieved at a dose of 30 mg / dm3, resulting in a 53% efficiency. Studies have shown that both tested powdered activated carbons have contributed to effective cleaning of aqueous solutions containing ibuprofen.

  4. ETV REPORT: REMOVAL OF ARSENIC IN DRINKING WATER ORCA WATER TECHNOLOGIES KEMLOOP 1000 COAGULATION AND FILTRATION WATER TREATMENT SYSTEM

    Science.gov (United States)

    Verification testing of the ORCA Water Technologies KemLoop 1000 Coagulation and Filtration Water Treatment System for arsenic removal was conducted at the St. Louis Center located in Washtenaw County, Michigan, from March 23 through April 6, 2005. The source water was groundwate...

  5. Effectiveness of table top water pitcher filters to remove arsenic from drinking water.

    Science.gov (United States)

    Barnaby, Roxanna; Liefeld, Amanda; Jackson, Brian P; Hampton, Thomas H; Stanton, Bruce A

    2017-10-01

    Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As 3+ and As 5+ , from 1000μg/L to water and its use reduces plastic waste associated with bottled water. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Grafted cellulose for PAHs removal present in industrial discharge waters

    Science.gov (United States)

    Euvrard, Elise; Druart, Coline; Poupeney, Amandine; Crini, Nadia; Vismara, Elena; Lanza, Tommaso; Torri, Giangiacomo; Gavoille, Sophie; Crini, Gregorio

    2014-05-01

    Keywords: cellulose; biosorbent; PAHs; polycontaminated wastewaters; trace levels. Polycyclic aromatic hydrocarbons (PAHs), chemicals essentially formed during incomplete combustion of organic materials from anthropogenic activities, were present in all compartments of the ecosystem, air, water and soil. Notably, a part of PAHs found in aquatic system was introduced through industrial discharge waters. Since the Water Framework Directive has classified certain PAHs as priority hazardous substances, industrials are called to take account this kind of organic pollutants in their global environmental concern. Conventional materials such as activated carbons definitively proved their worth as finishing treatment systems but remained costly. In this study, we proposed to use cellulose grafted with glycidyl methacrylate [1] for the removal of PAHs present in discharge waters of surface treatment industries. Firstly, to develop the device, we worked with synthetic solutions containing 16 PAHs at 500 ng/L. Two types of grafted cellulose were tested over a closed-loop column with a concentration of 4g cellulose/L: cellulose C2 with a hydroxide group and cellulose C4 with an amine group. No PAH was retained by the raw cellulose whereas abatement percentages of PAHs were similar between C2 and C4 (94% and 98%, respectively, for the sum of the 16 PAHs) with an experiment duration of 400 min (corresponding to about 20 cycles through grafted cellulose). Secondly, to determine the shorter time to abate the amount maximum of PAHs through the system, a kinetic was realized from 20 min (one cycle) to 400 min with C4. The steady state (corresponding to about 95% of abatement of the total PAHs) was reached at 160 min. Finally, the system was then tested with real industrial discharge waters containing both mineral and organic compounds. The results indicated that the abatement percentage of PAHs was similar between C2 and C4, corroborating the tests with synthetic solution. In return

  7. Phosphate removal from water using lithium intercalated gibbsite.

    Science.gov (United States)

    Wang, Shan-Li; Cheng, Chia-Yi; Tzou, Yu-Min; Liaw, Ren-Bao; Chang, Ta-Wei; Chen, Jen-Hshuan

    2007-08-17

    In this study, lithium intercalated gibbsite (LIG) was investigated for its effectiveness at removing phosphate from water and the mechanisms involved. LIG was prepared through intercalating LiCl into gibbsite giving a structure of [LiAl2(OH)6]+ layers with interlayer Cl- and water. The results of batch adsorption experiments showed that the adsorption isotherms at various pHs exhibited an L-shape and could be fitted well using the Langmuir model. The Langmuir adsorption maximum was determined to be 3.0 mmol g(-1) at pH 4.5 and decreased with increasing pH. The adsorption of phosphate was mainly through the displacement of the interlayer Cl- ions in LIG. In conjunction with the anion exchange reaction, the formation of surface complexes or precipitates could also readily occur at lower pH. The adsorption decreased with increasing pH due to decreased H(2)PO(4)(-)/HPO4(2-) molar ratio in solution and positive charges on the edge faces of LIG. Anion exchange is a fast reaction and can be completed within minutes; on the contrary, surface complexation is a slow process and requires days to reach equilibrium. At lower pH, the amount of adsorbed phosphate decreased significantly as the ionic strength was increased from 0.01 to 0.1M. The adsorption at higher pH showed high selectivity toward divalent HPO4(2-) ions with an increase in ionic strength having no considerable effect on the phosphate adsorption. These results suggest that LIG may be an effective scavenger for removal of phosphate from water.

  8. Effects of water removal on a Hawaiian stream ecosystem

    Science.gov (United States)

    Kinzie, R. A.; Chong, C.; Devrell, J.; Lindstrom, D.; Wolff, R.

    2006-01-01

    A 3-year study of Wainiha River on Kaua'i, Hawai'i, was carried out to determine the impact that water removal had on key stream ecosystem parameters and functions. The study area included a diversion dam for a hydroelectric plant that removes water at an elevation of 213 m and returns it to the stream about 6 km downstream at an elevation of 30 m. There were two high-elevation sites, one with undiverted flow and one with reduced flow, and two low-elevation sites, one with reduced flow and one with full flow restored. Monthly samples were taken of instream and riparian invertebrates and plants. When samples from similar elevations were compared, dewatered sites had lower concentrations of benthic photosynthetic pigments than full-flow sites, and benthic ash-free dry mass (AFDM) was higher at the two low-elevation sites regardless of flow. Benthic chlorophyll a (chl a) and AFDM were higher in summer months than in the winter. Benthic invertebrate abundance was highest at the full-flow, low-elevation site and benthic invertebrate biomass was highest at the full-flow, high-elevation site. Season had only marginal effects on abundance and biomass of benthic invertebrates. Diversity of benthic invertebrates was higher at the more-downstream sites. Abundance of drifting invertebrates was highest at the site above the diversion dam and generally higher in winter than in summer months. Biomass of drifting invertebrates was also highest at the above-dam site but there was little seasonal difference. Almost all parameters measured were lowest at the site just downstream of the diversion dam. The biotic parameters responded only weakly to flows that had occurred up to 1 month before the measurements were made. Flow, elevation, and season interact in complex ways that impact ecosystem parameters and functions, but water diversion can override all these environmental factors. ?? 2006 by University of Hawai'i Press All rights reserved.

  9. Phosphate removal from water using lithium intercalated gibbsite

    International Nuclear Information System (INIS)

    Wang, S.-L.; Cheng, C.-Y.; Tzou, Y.-M.; Liaw, R.-B.; Chang, T.-W.; Chen, J.-H.

    2007-01-01

    In this study, lithium intercalated gibbsite (LIG) was investigated for its effectiveness at removing phosphate from water and the mechanisms involved. LIG was prepared through intercalating LiCl into gibbsite giving a structure of [LiAl 2 (OH) 6 ] + layers with interlayer Cl - and water. The results of batch adsorption experiments showed that the adsorption isotherms at various pHs exhibited an L-shape and could be fitted well using the Langmuir model. The Langmuir adsorption maximum was determined to be 3.0 mmol g -1 at pH 4.5 and decreased with increasing pH. The adsorption of phosphate was mainly through the displacement of the interlayer Cl - ions in LIG. In conjunction with the anion exchange reaction, the formation of surface complexes or precipitates could also readily occur at lower pH. The adsorption decreased with increasing pH due to decreased H 2 PO 4 - /HPO 4 2- molar ratio in solution and positive charges on the edge faces of LIG. Anion exchange is a fast reaction and can be completed within minutes; on the contrary, surface complexation is a slow process and requires days to reach equilibrium. At lower pH, the amount of adsorbed phosphate decreased significantly as the ionic strength was increased from 0.01 to 0.1 M. The adsorption at higher pH showed high selectivity toward divalent HPO 4 2- ions with an increase in ionic strength having no considerable effect on the phosphate adsorption. These results suggest that LIG may be an effective scavenger for removal of phosphate from water

  10. Ceramic membrane ozonator for soluble organics removal from produced water

    Science.gov (United States)

    Siagian, U. W. R.; Dwipramana, A. S.; Perwira, S. B.; Khoiruddin; Wenten, I. G.

    2018-01-01

    In this work, the performance of ozonation for degradation of soluble organic compounds in produced water was investigated. Tubular ceramic membrane diffuser (with and without a static mixer in the lumen side) was used to facilitate contact between ozone and produced water. The ozonation was conducted at ozone flow rate of 8 L.min-1, ozone concentration of 0.4 ppm, original pH of the solution, and pressure of 1.2 bar, while the flow rates of the produced water were varied (192, 378 and 830 mL.min-1). It was found that the reduction of benzene, toluene, ethylbenzene, and xylene were 85%, 99%, 85%, and 95%, respectively. A lower liquid flow rate in a laminar state showed a better component reduction due to the longer contacting time between the liquid and the gas phase. The introduction of the static mixer in the lumen side of the membrane as a turbulence promoter provided a positive effect on the performance of the membrane diffuser. The twisted static mixer exhibited the better removal rate than the spiral static mixer.

  11. Dispersion of C(60) in natural water and removal by conventional drinking water treatment processes.

    Science.gov (United States)

    Hyung, Hoon; Kim, Jae-Hong

    2009-05-01

    The first objective of this study is to examine the fate of C(60) under two disposal scenarios through which pristine C(60) is introduced to water containing natural organic matter (NOM). A method based on liquid-liquid extraction and HPLC to quantify nC(60) in water containing NOM was also developed. When pristine C(60) was added to water either in the form of dry C(60) or in organic solvent, it formed water stable aggregates with characteristics similar to nC(60) prepared by other methods reported in the literature. The second objective of this study is to examine the fate of the nC(60) in water treatment processes, which are the first line of defense against ingestion from potable water -- a potential route for direct human consumption. Results obtained from jar tests suggested that these colloidal aggregates of C(60) were efficiently removed by a series of alum coagulation, flocculation, sedimentation and filtration processes, while the efficiency of removal dependent on various parameters such as pH, alkalinity, NOM contents and coagulant dosage. Colloidal aggregates of functionalized C(60) could be well removed by the conventional water treatment processes but with lesser efficiency compared to those made of pristine C(60).

  12. Desalination using spray tower and vapour compression refrigeration system

    International Nuclear Information System (INIS)

    Sathish Kumar, S.; Mani, A.

    2006-01-01

    A desalination system using a spray tower and Vapour Compression Refrigeration (VCR) system is proposed for obtaining fresh water from brackish water. In the spray tower, simultaneous heat and mass transfer take place between the brackish water and air, which results in the evaporation of the brackish water and humidification of the air. Fresh water is obtained from the humidified air by condensing the water vapour using a VCR system. Parametric studies were carried out to study the effect of various operational parameters on the fresh water production rate. (author)

  13. Pollution of water sources and removal of pollutants by advanced drinking-water treatment in China.

    Science.gov (United States)

    Wang, L; Wang, B

    2000-01-01

    The pollution of water resources and drinking water sources in China is described in this paper with basic data. About 90% of surface waters and over 60% of drinking water sources in urban areas have been polluted to different extents. The main pollutants present in drinking water sources are organic substances, ammonia nitrogen, phenols, pesticides and pathogenic micro-organisms, some of which cannot be removed effectively by the traditional water treatment processes like coagulation, sedimentation, filtration and chlorination, and the product water usually does not meet Chinese national drinking water standards, when polluted source water is treated. In some drinking-water plants in China, advanced treatment processes including activated carbon filtration and adsorption, ozonation, biological activated carbon and membrane separation have been employed for further treatment of the filtrate from a traditional treatment system producing unqualified drinking water, to make final product water meet the WHO guidelines and some developed countries' standards, as well as the Chinese national standards for drinking water. Some case studies of advanced water treatment plants are described in this paper as well.

  14. Removing NDMA (N,N-dimethylnitrosamine) from natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Mezyk, S P [California State University Long Beach, (United States); Cooper, W J [University of North Carolina at Wilmington, (United States); Bartels, D M [Argonne National Laboratory, (United States)

    2003-07-01

    Nitrosoamines are ubiquitous in water environments, and are of concern as they are potent carcinogens. In particular, N,N-dimethylnitrosamine (NDMA, (CH{sub 3}){sub 2} NNO) is volatile, and therefore has been detected around factories producing secondary amines or rocket fuel, in areas near industrial plants that use dimethylamine in organic synthesis, and even in foods and beverages that contain nitrite or which have been exposed to nitrous oxides. Various technologies have been suggested for removing trace levels of NDMA contamination from aqueous systems. However, Advanced Oxidation Technologies (AOTs), such as ozone, UV/ozone, and UV/H{sub 2}O{sub 2} , which use oxidation via the hydroxyl radical ({sup .}OH), or heterogeneous catalysis by TiO{sub 2} , sonolysis, or the electron beam process, which produce a mixture of oxidizing {sup .}OH radicals with reducing hydrated electrons (e{sup -}{sub aq} ) and hydrogen atoms ({sup .} H), may also produce unwanted stable products in the treatment. Some of these stable products, such as secondary amines, allow regeneration of NDMA to occur. To ensure that any process applied to NDMA contaminated water occurs efficiently and quantitatively a complete understanding of the chemistry involved under the conditions of use is necessary. This requires mathematical modeling of the process, which in turn needs reaction rate constants and mechanisms. In this study, absolute rate constants at room temperature for the reaction of the hydroxyl radical, hydrated electron, and hydrogen atom with NDMA in water have been determined using electron pulse radiolysis and absorption spectroscopy, (e{sup -}{sub aq} and {sup .}OH) and EPR free induction decay attenuation ({sup .}H) measurements. The specific values of (4.30{+-} 0.12) x 10 8 , (1.41 {+-} 0.02) x 10 10 , and (2.01 {+-} 0.03) x 10{sup 8} M{sup -1} s{sup -1} , respectively, demonstrate that the reductive destruction of this nitrosoamine would be the dominant removal pathway in any

  15. Removal of natural radionuclides from drinking water from private wells in Finland

    International Nuclear Information System (INIS)

    Huikuri, Pia; Salonen, Laina; Turtiainen, Tuukka

    1999-01-01

    Removal of natural radionuclides is often necessary in Finland when household water is taken from a drilled well. Removal of radionuclides by various methods from Finnish groundwaters were studied in a EU-research project, TENAWA. The results indicated that radon can be removed very efficiently (up to 99%) by applying aeration or granular activated carbon (GAC) filtration. Uranium and radium were also removed (over 94%) by using strong base anion (SBA) and strong acid cation (SAC) resins. The capability of reverse osmosis (RO) equipment to remove radionuclides was over 90% for uranium, radium and polonium. The water quality analyses indicated that water quality remained mostly good during the water treatment. (au)

  16. Efficiency of water removal from water/ethanol mixtures using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    M. A. Rodrigues

    2006-06-01

    Full Text Available Techniques involving supercritical carbon dioxide have been successfully used for the formation of drug particles with controlled size distributions. However, these processes show some limitations, particularly in processing aqueous solutions. A diagram walking algorithm based on available experimental data was developed to evaluate the effect of ethanol on the efficiency of water removal processes under different process conditions. Ethanol feeding was the key parameter resulting in a tenfold increase in the efficiency of water extraction.

  17. Representing the root water uptake process in the Common Land Model for better simulating the energy and water vapour fluxes in a Central Asian desert ecosystem

    NARCIS (Netherlands)

    Li, Longhui; van der Tol, C.; Chen, Xuelong; Jing, C.; Su, Zhongbo; Luo, G.; Tian, Xin

    2013-01-01

    The ability of roots to take up water depends on both root distribution and root water uptake efficiency. The former can be experimentally measured, while the latter is extremely difficult to determine. Yet a correct representation of root water uptake process in land surface models (LSMs) is

  18. Characterization of the molecular distribution of drugs in glassy solid dispersions at the nano-meter scale, using differential scanning calorimetry and gravimetric water vapour sorption techniques.

    Science.gov (United States)

    van Drooge, D J; Hinrichs, W L J; Visser, M R; Frijlink, H W

    2006-03-09

    The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T(g)), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam solid dispersions prepared by fusion for all drug loads tested (10-80 wt.%). The T(g) of these solid dispersions gradually changed with composition and decreased from 177 degrees C for pure PVP to 46 degrees C for diazepam. These observations indicate that diazepam was dispersed in PVP on a molecular level. However, in PVP-diazepam solid dispersions prepared by freeze drying, two T(g)'s were observed for drug loads above 35 wt.% indicating phase separation. One T(g) indicated the presence of amorphous diazepam clusters, the other T(g) was attributed to a PVP-rich phase in which diazepam was dispersed on a molecular level. With both the value of the latter T(g) and the DeltaC(p) of the diazepam glass transition the concentrations of molecular dispersed diazepam could be calculated (27-35 wt.%). Both methods gave similar results. Water vapour sorption (DVS) experiments revealed that the PVP-matrix was hydrophobised by the incorporated diazepam. TMDSC and DVS results were used to estimate the size of diazepam clusters in freeze dried PVP-diazepam solid dispersions, which appeared to be in the nano-meter range. The inulin-diazepam solid dispersions prepared by spray freeze drying showed one T(g) for drug loads up to 35 wt.% indicating homogeneous distribution on a molecular level. However, this T(g) was independent of the drug load, which is unexpected because diazepam has a lower T(g) than inulin (46 and 155 degrees C, respectively). For higher drug loads, a T(g) of diazepam as well as a T(g) of the inulin-rich phase was observed, indicating the formation of amorphous diazepam clusters. From the DeltaC(p) of the diazepam glass transition the amount of molecularly dispersed

  19. Inherent calibration of a blue LED-CE-DOAS instrument to measure iodine oxide, glyoxal, methyl glyoxal, nitrogen dioxide, water vapour and aerosol extinction in open cavity mode

    Directory of Open Access Journals (Sweden)

    R. Thalman

    2010-12-01

    Full Text Available The combination of Cavity Enhanced Absorption Spectroscopy (CEAS with broad-band light sources (e.g. Light-Emitting Diodes, LEDs lends itself to the application of cavity enhanced Differential Optical Absorption Spectroscopy (CE-DOAS to perform sensitive and selective point measurements of multiple trace gases and aerosol extinction with a single instrument. In contrast to other broad-band CEAS techniques, CE-DOAS relies only on the measurement of relative intensity changes, i.e. does not require knowledge of the light intensity in the absence of trace gases and aerosols (I0. We have built a prototype LED-CE-DOAS instrument in the blue spectral range (420–490 nm to measure nitrogen dioxide (NO2, glyoxal (CHOCHO, methyl glyoxal (CH3COCHO, iodine oxide (IO, water vapour (H2O and oxygen dimers (O4. We demonstrate the first direct detection of methyl glyoxal, and the first CE-DOAS detection of CHOCHO and IO. The instrument is further inherently calibrated for light extinction from the cavity by observing O4 or H2O (at 477 nm and 443 nm and measuring the pressure, relative humidity and temperature independently. This approach is demonstrated by experiments where laboratory aerosols of known size and refractive index were generated and their extinction measured. The measured extinctions were then compared to the theoretical extinctions calculated using Mie theory (3–7 × 10−7cm−1. Excellent agreement is found from both the O4 and H2O retrievals. This enables the first inherently calibrated CEAS measurement at blue wavelengths in open cavity mode, and eliminates the need for sampling lines to supply air to the cavity, i.e., keep the cavity enclosed and/or aerosol free. Measurements in open cavity mode are demonstrated for CHOCHO, CH3COCHO, NO2, H2O and aerosol extinction. Our prototype

  20. Removal of glyphosate herbicide from water using biopolymer membranes.

    Science.gov (United States)

    Carneiro, Rafael T A; Taketa, Thiago B; Gomes Neto, Reginaldo J; Oliveira, Jhones L; Campos, Estefânia V R; de Moraes, Mariana A; da Silva, Camila M G; Beppu, Marisa M; Fraceto, Leonardo F

    2015-03-15

    Enormous amounts of pesticides are manufactured and used worldwide, some of which reach soils and aquatic systems. Glyphosate is a non-selective herbicide that is effective against all types of weeds and has been used for many years. It can therefore be found as a contaminant in water, and procedures are required for its removal. This work investigates the use of biopolymeric membranes prepared with chitosan (CS), alginate (AG), and a chitosan/alginate combination (CS/AG) for the adsorption of glyphosate present in water samples. The adsorption of glyphosate by the different membranes was investigated using the pseudo-first order and pseudo-second order kinetic models, as well as the Langmuir and Freundlich isotherm models. The membranes were characterized regarding membrane solubility, swelling, mechanical, chemical and morphological properties. The results of kinetics experiments showed that adsorption equilibrium was reached within 4 h and that the CS membrane presented the best adsorption (10.88 mg of glyphosate/g of membrane), followed by the CS/AG bilayer (8.70 mg of glyphosate/g of membrane). The AG membrane did not show any adsorption capacity for this herbicide. The pseudo-second order model provided good fits to the glyphosate adsorption data on CS and CS/AG membranes, with high correlation coefficient values. Glyphosate adsorption by the membranes could be fitted by the Freundlich isotherm model. There was a high affinity between glyphosate and the CS membrane and moderate affinity in the case of the CS/AG membrane. Physico-chemical characterization of the membranes showed low values of solubility in water, indicating that the membranes are stable and not soluble in water. The SEM and AFM analysis showed evidence of the presence of glyphosate on CS membranes and on chitosan face on CS/AG membranes. The results showed that the glyphosate herbicide can be adsorbed by chitosan membranes and the proposed membrane-based methodology was successfully used to

  1. Removal of cadmium and lead from water by activated carbon

    International Nuclear Information System (INIS)

    Abdel-Shafy, H.I.; Abdel-Sabour, M.F.; El-Gamal, I.M.; Abo-El-Wafa, O.

    1989-01-01

    Adsorption of cadmium and lead from water by carbon was studied using powdered or granular carbon. The studied water artificially contaminated by cadmium and lead amounting to 1 mg/dm 3 each. Batch as well as continuous system were carried out. The batch system was used to determine the time to maintain equilibrium followed by adsorption isotherm. Results obtained by using the powered carbon were found to match with Freundlich's equation where 1/n was 2.12 and 2.096 for Cd and Pb, respectively. Corresponding constants (K) were 4.2·10 -2 and 76.0·10 -2 . The amount of powdered activated carbon required to reduce residual Cd and Pb concentration to 0.01 mg/dm 3 for each are 26.98 and 2.86 mg, respectively. Similar batch system study was carried out for the granular carbon. When granular carbon was used in a continuous system, two different contact times, namely 10 to 20 min were examined. The results obtained showed that increasing the contact time from 10 to 20 min increases the metal to carbon removal efficiency. The overall results indicated that the breakthrough point for either Cd or Pb is the reverse of their adsorption as indicated by K value. (author). 22 refs, 10 figs, 7 tabs

  2. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2012-09-12

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

  3. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev; Patankar, Neelesh A.; Marston, Jeremy; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2012-01-01

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

  4. Tritium in the food chain. Intercomparison of model predictions of contamination in soil, crops, milk and beef after a short exposure to tritiated water vapour in air

    International Nuclear Information System (INIS)

    Barry, P.

    1996-09-01

    Future fusion reactors using tritium as fuel will contain large inventories of the gas. The possibility that a significant fraction of an inventory may accidentally escape into the atmosphere from this and other potential sources such as tritium handling facilities and some fission reactors e g, PWRs has to be recognized and its potential impact on local human populations and biota assessed. Tritium gas is relatively inert chemically and of low radiotoxicity but it is readily oxidized by soil organisms to the mixed oxide, HTO or tritiated water. In this form it is highly mobile, strongly reactive biologically and much more toxic. Models of how tritiated water vapour is transported through the biosphere to foodstuffs important to man are essential components of such an assessment and it is important to test the models for their suitability when used for this purpose. To evaluate such models, access to experimental measurements made after actual releases are needed. There have however, been very few accidental releases of tritiated water to the atmosphere and the experimental findings of those that have occurred have been used to develop the models under test. Models must nevertheless be evaluated before their predictions can be used to decide the acceptability or otherwise of designing and operating major nuclear facilities. To fulfil this need a model intercomparison study was carried out for a hypothetical release scenario. The study described in this report is a contribution to the development of model evaluation procedures in general as well as a description of the results of applying these procedures to the particular case of models of HTO transport in the biosphere which are currently in use or being developed. The study involved eight modelers using seven models in as many countries. In the scenario farmland was exposed to 1E10 Bq d/m 3 of HTO in air during 1 hour starting at midnight in one case and at 10.00 a.m. in the other, 30 days before harvest of crops

  5. Tritium in the food chain. Intercomparison of model predictions of contamination in soil, crops, milk and beef after a short exposure to tritiated water vapour in air

    Energy Technology Data Exchange (ETDEWEB)

    Barry, P. [PJS Barry (Canada)] [and others

    1996-09-01

    Future fusion reactors using tritium as fuel will contain large inventories of the gas. The possibility that a significant fraction of an inventory may accidentally escape into the atmosphere from this and other potential sources such as tritium handling facilities and some fission reactors e g, PWRs has to be recognized and its potential impact on local human populations and biota assessed. Tritium gas is relatively inert chemically and of low radiotoxicity but it is readily oxidized by soil organisms to the mixed oxide, HTO or tritiated water. In this form it is highly mobile, strongly reactive biologically and much more toxic. Models of how tritiated water vapour is transported through the biosphere to foodstuffs important to man are essential components of such an assessment and it is important to test the models for their suitability when used for this purpose. To evaluate such models, access to experimental measurements made after actual releases are needed. There have however, been very few accidental releases of tritiated water to the atmosphere and the experimental findings of those that have occurred have been used to develop the models under test. Models must nevertheless be evaluated before their predictions can be used to decide the acceptability or otherwise of designing and operating major nuclear facilities. To fulfil this need a model intercomparison study was carried out for a hypothetical release scenario. The study described in this report is a contribution to the development of model evaluation procedures in general as well as a description of the results of applying these procedures to the particular case of models of HTO transport in the biosphere which are currently in use or being developed. The study involved eight modelers using seven models in as many countries. In the scenario farmland was exposed to 1E10 Bq d/m{sup 3} of HTO in air during 1 hour starting at midnight in one case and at 10.00 a.m. in the other, 30 days before harvest of

  6. The stable isotopic composition of water vapour above Corsica during the HyMeX SOP1 campaign: insight into vertical mixing processes from lower-tropospheric survey flights

    Science.gov (United States)

    Sodemann, Harald; Aemisegger, Franziska; Pfahl, Stephan; Bitter, Mark; Corsmeier, Ulrich; Feuerle, Thomas; Graf, Pascal; Hankers, Rolf; Hsiao, Gregor; Schulz, Helmut; Wieser, Andreas; Wernli, Heini

    2017-05-01

    Stable isotopes of water vapour are powerful indicators of meteorological processes on a broad range of scales, reflecting evaporation, condensation, and air mass mixing processes. With the recent advent of fast laser-based spectroscopic methods, it has become possible to measure the stable isotopic composition of atmospheric water vapour in situ at a high temporal resolution. Here we present results from such comprehensive airborne spectroscopic isotope measurements in water vapour over the western Mediterranean at a high spatial and temporal resolution. Measurements have been acquired by a customized Picarro L2130-i cavity-ring down spectrometer deployed onboard the Dornier 128 D-IBUF aircraft together with a meteorological flux measurement package during the HyMeX SOP1 (Hydrological cycle in Mediterranean Experiment special observation period 1) field campaign in Corsica, France, during September and October 2012. Taking into account memory effects of the air inlet pipe, the typical time resolution of the measurements was about 15-30 s, resulting in an average horizontal resolution of about 1-2 km. Cross-calibration of the water vapour measurements from all humidity sensors showed good agreement under most flight conditions but the most turbulent ones. In total 21 successful stable isotope flights with 59 flight hours have been performed. Our data provide quasi-climatological autumn average conditions and vertical profiles of the stable isotope parameters δD, δ18O, and d-excess during the study period. A d-excess minimum in the overall average profile is reached in the region of the boundary-layer top, possibly caused by precipitation evaporation. This minimum is bracketed by higher d-excess values near the surface caused by non-equilibrium fractionation, and a maximum above the boundary layer related to the increasing d-excess in very depleted and dry high-altitude air masses. Repeated flights along the same pattern reveal pronounced day-to-day variability

  7. Optimized sampling of hydroperoxides and investigations of the water vapour dependence of hydroperoxide formation during ozonolysis of alkenes; Optimierung der Probenahme von Hydroperoxiden und Untersuchungen zur Wasserdampfabhaengigkeit der Bildung von Hydroperoxiden bei der Ozonolyse von Alkenen

    Energy Technology Data Exchange (ETDEWEB)

    Becker, K.H.; Plagens, H.

    1997-06-01

    There are several sampling methods for hydroperoxides none of which is particularly reliable. The authors therefore tested three new methods in order to optimize hydroperoxide sampling and, using the optimized sampling procedure, to investigate the water vapour dependence of hydroperoxide formation during ozonolysis of alkenes. (orig.) [Deutsch] Fuer die Probenahme von Hydroperoxiden existieren verschiedene Verfahren, von denen bisher keines als besonders zuverlaessig angesehen werden konnte. Daher wurden in dieser Arbeit drei Verfahren getestet, um die Probenahme von Hydroperoxiden zu optimieren und mit dem entsprechenden Verfahren die Wasserdampfabhaengigkeit der Bildung von Hydroperoxiden bei der Ozonolyse von Alkenen zu untersuchen. (orig.)

  8. An example of transition from a corrosion process in gaseous phase to corrosion in aqueous environment: the case of Z2CN18-10 stainless steel by iodine and water in vapour phase

    International Nuclear Information System (INIS)

    Mathieu, Bruno

    1990-01-01

    This research thesis addresses an example of transition of a corrosion process in gaseous phase towards corrosion in aqueous environment, specifically in the case of the corrosion of the Z2CN18-10 stainless steel by gaseous iodine in presence of water vapour (and possibly nitrogen dioxide). This transition occurs in two steps: initiation in gaseous phase and growth in aqueous environment. This transition is due to hygroscopic properties of mostly chromium iodides and, to a lesser extent, iron iodides. Morphological, electrochemical and thermogravimetry studies have been performed by varying different parameters governing corrosion processes: corrosion temperature, iodine concentration, relative humidity, and reaction time [fr

  9. 7 CFR 701.53 - Debris removal and water for livestock.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Debris removal and water for livestock. 701.53 Section... RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART § 701.53 Debris removal and water for livestock..., and for providing water for livestock. [71 FR 30265, May 26, 2006] ...

  10. Autotrophic nitrogen removal process in a potable water treatment biofilter that simultaneously removes Mn and NH4(+)-N.

    Science.gov (United States)

    Cai, Yan'an; Li, Dong; Liang, Yuhai; Zeng, Huiping; Zhang, Jie

    2014-11-01

    Ammonia (NH4(+)-N) removal pathways were investigated in a potable water treatment biofilter that simultaneously removes manganese (Mn) and NH4(+)-N. The results indicated a significant loss of nitrogen in the biofilter. Both the completely autotrophic nitrogen removal over nitrite (CANON) process and nitrification were more likely to contribute to NH4(+)-N removal. Moreover, the model calculation results demonstrated that the CANON process contributed significantly to the removal of NH4(+)-N. For influent NH4(+)-N levels of 1.030 and 1.749mg/L, the CANON process contribution was about 48.5% and 46.6%, respectively. The most important finding was that anaerobic ammonia oxidation (ANAMMOX) bacteria were detectable in the biofilter. It is interesting that the CANON process was effective even for such low NH4(+)-N concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Simultaneous Hydrogen Sulphide and Carbon Dioxide Removal from Biogas by Water-Swollen Reverse Osmosis Membrane

    Czech Academy of Sciences Publication Activity Database

    Dolejš, Petr; Poštulka, Václav; Sedláková, Zuzana; Jandová, Věra; Vejražka, Jiří; Esposito, E.; Jansen, J.C.; Izák, Pavel

    2014-01-01

    Roč. 131, JUN 27 (2014), s. 108-116 ISSN 1383-5866 R&D Projects: GA ČR GAP106/10/1194; GA ČR GA14-12695S; GA TA ČR TE01020080; GA MŠk LH14006; GA MŠk(CZ) 7C11009; GA MŠk(CZ) LD13018 Grant - others:RFCS(XE) RFCRCT-2010-00009; PONRC(IT) PON01_01840 Institutional support: RVO:67985858 Keywords : agro-biogas upgrading * biomethane * water vapour Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.091, year: 2014

  12. Modelling of decay heat removal using large water pools

    International Nuclear Information System (INIS)

    Munther, R.; Raussi, P.; Kalli, H.

    1992-01-01

    The main task for investigating of passive safety systems typical for ALWRs (Advanced Light Water Reactors) has been reviewing decay heat removal systems. The reference system for calculations has been represented in Hitachi's SBWR-concept. The calculations for energy transfer to the suppression pool were made using two different fluid mechanics codes, namely FIDAP and PHOENICS. FIDAP is based on finite element methodology and PHOENICS uses finite differences. The reason choosing these codes has been to compare their modelling and calculating abilities. The thermal stratification behaviour and the natural circulation was modelled with several turbulent flow models. Also, energy transport to the suppression pool was calculated for laminar flow conditions. These calculations required a large amount of computer resources and so the CRAY-supercomputer of the state computing centre was used. The results of the calculations indicated that the capabilities of these codes for modelling the turbulent flow regime are limited. Output from these codes should be considered carefully, and whenever possible, experimentally determined parameters should be used as input to enhance the code reliability. (orig.). (31 refs., 21 figs., 3 tabs.)

  13. ARSENIC REMOVAL FROM DRINKING WATER BY IRON REMOVAL. USEPA DEMONSTRATION PROJECT AT CLIMAX, MN. PROJECT SUMMARY

    Science.gov (United States)

    This document is an eight page summary of the final report on arsenic demonstration project at Climax, MN (EPA/600/R-06/152). The objectives of the project are to evaluate the effectiveness of the Kinetico iron removal system in removing arsenic to meet the new arsenic maximum co...

  14. Absorption of water vapour in the falling film of water-(LiBr + LiI + LiNO{sub 3} + LiCl) in a vertical tube at air-cooling thermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bourouis, Mahmoud; Valles, Manel; Medrano, Marc; Coronas, Alberto [Centro de Innovacion Tecnologica en Revalorizacion Energetica y Refrigeracion, CREVER, Universitat Rovira i Virgili, Autovia de Salou, s/n, 43006, Tarragona (Spain)

    2005-05-01

    In air-cooled water-LiBr absorption chillers the working conditions in the absorber and condenser are shifted to higher temperatures and concentrations, thereby increasing the risk of crystallisation. To develop this technology, two main problems are to be addressed: the availability of new salt mixtures with wider range of solubility than water-LiBr, and advanced absorber configurations that enable to carry out simultaneously an appropriate absorption process and an effective air-cooling. One way of improving the solubility of LiBr aqueous solutions is to add other salts to create multicomponent salt solutions. The aqueous solution of the quaternary salt system (LiBr + LiI + LiNO{sub 3} + LiCl) presents favourable properties required for air-cooled absorption systems: less corrosive and crystallisation temperature about 35 K lower than that of water-LiBr.This paper presents an experimental study on the absorption of water vapour over a wavy laminar falling film of an aqueous solution of (LiBr + LiI + LiNO{sub 3} + LiCl) on the inner wall of a water-cooled smooth vertical tube. Cooling water temperatures in the range 30-45 C were selected to simulate air-cooling thermal conditions. The results are compared with those obtained in the same experimental set-up with water-LiBr solutions.The control variables for the experimental study were: absorber pressure, solution Reynolds number, solution concentration and cooling water temperature. The parameters considered to assess the absorber performance were: absorber thermal load, mass absorption flux, degree of subcooling of the solution leaving the absorber, and the falling film heat transfer coefficient.The higher solubility of the multicomponent salt solution makes possible the operation of the absorber at higher salt concentration than with the conventional working fluid water-LiBr. The absorption fluxes achieved with water-(LiBr + LiI + LiNO{sub 3} + LiCl) at a concentration of 64.2 wt% are around 60 % higher than

  15. Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water.

    Science.gov (United States)

    Carey, Manus; Jiujin, Xiao; Gomes Farias, Júlia; Meharg, Andrew A

    2015-01-01

    A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (Asi) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more Asi removed by cooking, suggesting that the Asi in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in Asi, or Asi free. This has the advantage of not only exposing grain to large volumes of cooking water, but also physically removes any Asi leached from the grain into the water receiving vessel. The relationship between cooking water volume and Asi removal in conventional rice cooking was demonstrated for the rice types under study. At a water-to-rice cooking ratio of 12:1, 57±5% of Asi could be removed, average of 6 wholegrain and 6 polished rice samples. Two types of percolating technology were tested, one where the cooking water was recycled through condensing boiling water steam and passing the freshly distilled hot water through the grain in a laboratory setting, and one where tap water was used to cook the rice held in an off-the-shelf coffee percolator in a domestic setting. Both approaches proved highly effective in removing Asi from the cooking rice, with up to 85% of Asi removed from individual rice types. For the recycled water experiment 59±8% and 69±10% of Asi was removed, on average, compared to uncooked rice for polished (n=27) and wholegrain (n=13) rice, respectively. For coffee percolation there was no difference between wholegrain and polished rice, and the effectiveness of Asi removal was 49±7% across 6 wholegrain and 6 polished rice samples. The manuscript explores the potential applications and further optimization of this percolating cooking water, high Asi removal, discovery.

  16. Summer to Winter Diurnal Variabilities of Temperature and Water Vapour in the Lowermost Troposphere as Observed by HAMSTRAD over Dome C, Antarctica

    Science.gov (United States)

    Ricaud, P.; Genthon, C.; Durand, P.; Attié, J.-L.; Carminati, F.; Canut, G.; Vanacker, J.-F.; Moggio, L.; Courcoux, Y.; Pellegrini, A.; Rose, T.

    2012-04-01

    The HAMSTRAD (H2O Antarctica Microwave Stratospheric and Tropospheric Radiometers) microwave radiometer operating at 60 GHz (oxygen line, thus temperature) and 183 GHz (water vapour line) has been permanently deployed at the Dome C station, Concordia, Antarctica [75°06'S, 123°21'E, 3,233 m above mean sea level] in January 2010 to study long-term trends in tropospheric absolute humidity and temperature. The great sensitivity of the instrument in the lowermost troposphere helped to characterize the diurnal cycle of temperature and H2O from the austral summer (January 2010) to the winter (June 2010) seasons from heights of 10 to 200 m in the planetary boundary layer (PBL). The study has characterized the vertical resolution of the HAMSTRAD measurements: 10-20 m for temperature and 25-50 m for H2O. A strong diurnal cycle in temperature and H2O (although noisier) has been measured in summertime at 10 m, decreasing in amplitude with height, and phase-shifted by about 4 h above 50 m with a strong H2O-temperature correlation (>0.8) throughout the entire PBL. In autumn, whilst the diurnal cycle in temperature and H2O is less intense, a 12-h phase shift is observed above 30 m. In wintertime, a weak diurnal signal measured between 10 to 200 m is attributed to the methodology employed, which consists of monthly averaged data, and that combines air masses from different origins (sampling effect) and not to the imprint of the null solar irradiation. In situ sensors scanning the entire 24-h period, radiosondes launched at 2000 local solar time (LST) and European Centre for Medium-Range Weather Forecasts (ECMWF) analyses at 0200, 0800, 1400 and 2000 LST agree very well with the HAMSTRAD diurnal cycles for temperature and relatively well for absolute humidity. For temperature, HAMSTRAD tends to be consistent with all the other datasets but shows a smoother vertical profile from 10 to 100 m compared to radiosondes and in-situ data, with ECMWF profiles even smoother than HAMSTRAD

  17. Removal efficiency of water purifier and adsorbent for iodine, cesium, strontium, barium and zirconium in drinking water.

    Science.gov (United States)

    Sato, Itaru; Kudo, Hiroaki; Tsuda, Shuji

    2011-01-01

    The severe incident of Fukushima Daiichi Nuclear Power Station has caused radioactive contamination of environment including drinking water. Radioactive iodine, cesium, strontium, barium and zirconium are hazardous fission products because of the high yield and/or relatively long half-life. In the present study, 4 pot-type water purifiers and several adsorbents were examined for the removal effects on these elements from drinking water. Iodide, iodate, cesium and barium were removed by all water purifiers with efficiencies about 85%, 40%, 75-90% and higher than 85%, respectively. These efficiencies lasted for 200 l, which is near the recommended limits for use of filter cartridges, without decay. Strontium was removed with initial efficiencies from 70% to 100%, but the efficiencies were slightly decreased by use. Zirconium was removed by two models, but hardly removed by the other models. Synthetic zeolite A4 efficiently removed cesium, strontium and barium, but had no effect on iodine and zirconium. Natural zeolite, mordenite, removed cesium with an efficiency as high as zeolite A4, but the removal efficiencies for strontium and barium were far less than those of zeolite A4. Activated carbon had little removal effects on these elements. In case of radioactive contamination of tap water, water purifiers may be available for convenient decontamination of drinking water in the home.

  18. Activated soil filters for removal of biocides from contaminated run-off and waste-waters

    DEFF Research Database (Denmark)

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael

    2011-01-01

    -Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone). However, this removal is a considerable improvement compared to direct discharge into surface waters or infiltration into soil without appropriate removal. In the last experiment the removal efficiencies of the different layers were studied. Though the peat layer...

  19. Considering the use of polyethylene vapour barriers in temperate climates

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, M.D. [Morrison Hershfield Ltd., Vancouver, BC (Canada); Brown, W.C. [Morrison Hershfield Ltd., Ottawa, ON (Canada)

    2003-07-01

    Most building envelope assemblies in Canada must include a vapour barrier in order to comply with Canadian building codes. The installation of sheet polyethylene between the studs and the interior sheathing has been the most common method because it provides more diffusion resistance than necessary to control condensation within a building envelope assembly. It has been suggested that the presence of a polyethylene vapour barrier on the warm-in-winter side of the insulation may actually cause moisture problems because a very low permeance material increases average moisture levels. This paper examined the theory that a vapour barrier at this location restricts drying of moisture that enters the building from outside. Pacific coastal regions of Canada and the United States were presented as examples. Other ways that a polyethylene vapour barrier affects wall performance were also presented. The advanced hygrothermal model HygIRC, developed by Canada's National Research Council, was used to simulate the performance of a wall assembly. Results indicate that eliminating the low permeance polyethylene vapour barrier does not necessarily reduce the risk of moisture problems. Removal of the vapour barrier may have some negative effects, such as increased risk of periodic moisture accumulation and mold growth on paper-faced gypsum board. 7 refs., 2 tabs., 7 figs.

  20. REMOVAL OF BERYLLIUM FROM DRINKING WATER BY CHEMICAL COAGULATION AND LIME SOFTENING

    Science.gov (United States)

    The effectiveness of conventional drinking water treatment and lime softening was evaluated for beryllium removal from two drinking water sources. ar test studies were conducted to determine how common coagulants (aluminum sulfate and ferric chloride and lime softening performed ...

  1. Nanofiltration vs. reverse osmosis for the removal of emerging organic contaminants in water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor; Maeng, Sungkyu; Fujioka, Takahiro; Kennedy, Maria Dolores; Li, Zhenyu; Amya, Gary

    2011-01-01

    Reverse osmosis (RO) in existing water reuse facilities is a water industry standard. However, that approach may be questioned taking into consideration that "tight" NF can be equal or "better" than RO. NF can achieve the same removals of RO

  2. Subsurface iron and arsenic removal for drinking water treatment in Bangladesh

    NARCIS (Netherlands)

    Van Halem, D.

    2011-01-01

    Arsenic contamination of shallow tube well drinking water is an urgent health problem in Bangladesh. Current arsenic mitigation solutions, including (household) arsenic removal options, do not always provide a sustainable alternative for safe drinking water. A novel technology, Subsurface Arsenic

  3. Performance of water filters towards the removal of selected ...

    African Journals Online (AJOL)

    Organic matter removal was found to be 47%, 43%, 53%, 43.4% for bio-sand, slow sand, ceramic and membrane purifier respectively, while, fluoride removal was found to be 95.5% for bone char filter. Furthermore, filters were also assessed in terms of media availability, buying costs, operation, benefits/ effectiveness ...

  4. Sulphate Removal from Water by Carbon Residue from Biomass Gasification: Effect of Chemical Modification Methods on Sulphate Removal Efficiency

    Directory of Open Access Journals (Sweden)

    Hanna Runtti

    2016-02-01

    Full Text Available Sulphate removal from mine water is a problem because traditional chemical precipitation does not remove all sulphates. In addition, it creates lime sediment as a secondary waste. Therefore, an inexpensive and environmental-friendly sulphate removal method is needed in addition to precipitation. In this study, carbon residues from a wood gasification process were repurposed as precursors to a suitable sorbent for SO42- ion removal. The raw material was modified using ZnCl2, BaCl2, CaCl2, FeCl3, or FeCl2. Carbon residues modified with FeCl3 were selected for further consideration because the removal efficiency toward sulphate was the highest. Batch sorption experiments were performed to evaluate the effects of the initial pH, initial SO42- ion concentration, and contact time on sulphate removal. The removal of SO42- ions using Fe-modified carbon residue was notably higher compared with unmodified carbon residue and commercially available activated carbon. The sorption data exhibited pseudo-second-order kinetics. The isotherm analysis indicated that the sorption data of Fe-modified carbon residues can be represented by the bi-Langmuir isotherm model.

  5. Removal of radionuclides from household water; Metoder foer avlaegsnande av radionuklider fraan hushaallsvatten

    Energy Technology Data Exchange (ETDEWEB)

    Vesterbacka, P.; Turtiainen, T.; Haemaelaeinen, K.; Salonen, L.; Arvela, H.

    2007-02-15

    Research upon methods for removing radionuclides from household water was initiated in Finland in 1995. Three research projects, of which two were carried out with National Technology Agency of Finland and one with CEC, have been completed by the end of 2002. One of the main objectives of the research was to compose a guidebook for consumers and water treatment companies. Radon can be removed from household water by aeration and by activated carbon filtration. Aerators that are well designed and set up can remove over 90% of waterborne radon. The best aerators have achieved removal efficiencies that are nearly 100%. However, setting up an aeration system requires thorough planning. Also, activated carbon filtration removes radon efficiently. The removal efficiencies have been over 90%, often nearly 100%. Depending on the water quality and usage, the carbon batch inside the filter needs to be changed every 2 - 3 years. Since activated carbon filters emit gamma radiation while in use, they should not be installed inside the dwelling but in a separate building or by the well. It is recommended that uranium be removed from drinking water by anion exchange, which is the most efficient removal method for this purpose. Typically, the removal efficiencies are nearly 100%. The one exception is the so called tap filter, the removal efficiency of which depends on uranium concentration in raw water and the rate of water flow. High saline concentration in water may extricate uranium from ion exchange resin. Changes in plumbing pressure or pH-value do not have any significant influence in uranium retention. Removal efficiencies of lead and polonium vary a lot depending on the chemical form in which they occur in water. They can be reliably removed from water by reverse osmosis only. Other treatment methods, such as ion exchange and activated carbon filtration, remove lead and polonium partly. Lead and polonium are removed more efficiently when they are bound onto smaller

  6. Costs of Arsenic Removal Technologies for Small Water Systems: U.S. EPA Arsenic Removal Technology Demonstration Program

    Science.gov (United States)

    As part of the Arsenic Rule Implementation Research Program, between July 2003 and July 2011, the U.S. environmental Protection Agency (EPA) conducted 50 full-scale demonstration projects on treatment systems removing arsenic from drinking water in 26 states throughout the U.S. ...

  7. Removal of aqueous nC60 fullerene from water by low pressure membrane filtration

    NARCIS (Netherlands)

    Floris, R.; Nijmeijer, K.; Cornelissen, E. R.

    2016-01-01

    The potential environmental and health risks of engineered nanoparticles such as buckminsterfullerene C60 in water require their removal during the production of drinking water. We present a study focusing on (i) the removal mechanism and (ii) the elucidation of the role of the membrane pore size

  8. Removal of micropollutants from aerobically treated grey water via ozone and activated carbon

    NARCIS (Netherlands)

    Hernandez Leal, L.; Temmink, B.G.; Zeeman, G.; Buisman, C.J.N.

    2011-01-01

    Ozonation and adsorption onto activated carbon were tested for the removal micropollutants of personal care products from aerobically treated grey water. MilliQ water spiked with micropollutants (100–1600 µgL-1) was ozonated at a dosing rate of 1.22. In 45 min, this effectively removed (>99%):

  9. Rate Constants for the Reactions of OH with CO, NO and NO2, and of HO2 with NO2 in the Presence of Water Vapour at Lower-Tropospheric Conditions

    Science.gov (United States)

    Rolletter, Michael; Fuchs, Hendrik; Novelli, Anna; Ehlers, Christian; Hofzumahaus, Andreas

    2016-04-01

    Recent studies have shown that the chemistry of gaseous nitrous acid (HONO) in the lower troposphere is not fully understood. Aside from heterogenous reactions, the daytime HONO formation in the gas-phase is not well understood (Li et al., Science, 2014). For a better understanding of HONO in the gas-phase, we have reinvestigated the reaction rate constants of important tropospheric reactions of the HOx radical family (OH and HO2) with nitrogen oxides at realistic conditions of the lower troposphere (at ambient temperature/pressure and in humid air). In this study we apply a direct pump and probe technique with high accuracy, using small radical concentrations to avoid secondary chemistry. Pulsed laser photolysis/laser-induced fluorescence (LP/LIF) was used to investigate the reaction rate constants of OH with CO, NO, NO2, and HO2 with NO2 in synthetic air at different water vapor concentrations (up to 5 x 1017 molecules cm-3). Photolysis of ozone in the presence of gaseous water was the source of OH. The reactions took place in a flow-tube at room temperature and atmospheric pressure. The chemical decay of the radicals was monitored by laser-induced fluorescence detection in a low-pressure cell, which sampled air continuously from the end of the flow-tube. Knowing the reactant concentrations subsequently allowed to calculate the bimolecular reaction rate constants at 1 atm from the pseudo-first-order decays. In order to observe HO2 reactions, OH was converted into HO2 with an excess of CO in the flow-tube. The newly measured rate constants for OH with CO, NO and NO2 agree very well with current recommendations by NASA/JPL and IUPAC and have an improved accuracy (uncertainty < 5%). These rate coefficients are independent of the presence of water vapour. The measured rate constant of HO2 with NO2 was found to depend significantly on the water-vapour concentration (probably due to formation of HO2*H2O complexes) and to exceed current recommendations by NASA/JPL and

  10. Exploratory study on prevaporation membranes for removal of water from water-crude oil emulsions

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-11

    The main objective of this study was to explore the feasibility of removing water from oil/water and water/oil emulsions by means of prevaporation. Simulated oil/water and water/oil emulsions were prepared by mixing water and kerosene of various concentrations and stabilized by adding sodium lauryl sulfate. Preliminary experiments were conducted on 12 membranes fabricated from two different materials. One membrane of each type of material was chosen for further work based on the results of preliminary tests, in which two different kinds of membranes, cellulose and polyvinylalcohol, were used. All experiments were carried out under two different down-stream pressures and various temperatures. The tests showed clearly that permeation rate increases at increasing temperatures. It was demonstrated that over 97% of water can be recovered from synthetic oil emulsions. The results also proved that both cellulose and polyvinylalcohol membranes produced permeates relatively free of oil even when the synthetic or crude oil emulsions had oil content higher than 90%. The study concluded that prevaporation was effective, but more extensive studies on various field oil emulsions with improved membrane material and systems were necessary due to the complex and site-specific characteristics of the actual field emulsions. 3 figs., 8 tabs.

  11. Micropollutant removal from black water and grey water sludge in a UASB-GAC reactor.

    Science.gov (United States)

    Butkovskyi, A; Sevenou, L; Meulepas, R J W; Hernandez Leal, L; Zeeman, G; Rijnaarts, H H M

    2018-02-01

    The effect of granular activated carbon (GAC) addition on the removal of diclofenac, ibuprofen, metoprolol, galaxolide and triclosan in a up-flow anaerobic sludge blanket (UASB) reactor was studied. Prior to the reactor studies, batch experiments indicated that addition of activated carbon to UASB sludge can decrease micropollutant concentrations in both liquid phase and sludge. In continuous experiments, two UASB reactors were operated for 260 days at an HRT of 20 days, using a mixture of source separated black water and sludge from aerobic grey water treatment as influent. GAC (5.7 g per liter of reactor volume) was added to one of the reactors on day 138. No significant difference in COD removal and biogas production between reactors with and without GAC addition was observed. In the presence of GAC, fewer micropollutants were washed out with the effluent and a lower accumulation of micropollutants in sludge and particulate organic matter occurred, which is an advantage in micropollutant emission reduction from wastewater. However, the removal of micropollutants by adding GAC to a UASB reactor would require more activated carbon compared to effluent post-treatment. Additional research is needed to estimate the effect of bioregeneration on the lifetime of activated carbon in a UASB-GAC reactor.

  12. Removal of arsenic from ground water samples collected from West Bengal, India

    International Nuclear Information System (INIS)

    Ajith, Nicy; Swain, K.K.; Dalvi, Aditi A.; Verma, R.

    2015-01-01

    Arsenic contamination in ground water is one of the major concerns in many parts of the world including Bangladesh and India. Considering the high toxicity of arsenic, World Health Organization (WHO) has set a provisional guideline value of 10 μg L -1 for arsenic in drinking water. Several methods have been adopted for the removal of arsenic from drinking water. Most of the methods fail to remove As(III), the most toxic form of arsenic. An extra oxidative treatment step is essential for effective removal of total arsenic. Manganese dioxide (MnO 2 ) oxidizes As(III) to As(V). Removal of arsenic from water using manganese dioxide has been reported. During this work, removal of arsenic from ground water samples collected from arsenic contaminated area of West Bengal, India were carried out using MnO 2

  13. Trace Elements Removal from Waster water by Ceratophyllum ...

    African Journals Online (AJOL)

    Michael Horsfall

    Submerged aquatic plants can be used for the removal of Trace elements. The aim of this study was ... such as electroplating, metal finishing, textile, storage batteries, lead .... metals, Randomized Complete Block Design was used. Statistical ...

  14. Removal and recovery of heavy metals of residual water industrial

    International Nuclear Information System (INIS)

    Gil P, Edison

    1999-01-01

    On the next work the state of the art about the different methods and technologies for the present removal and recovery of heavy metals for the de-contamination and control of industrial wastewater is presented. Further more, it is introduce a removal alternative for chromium (III) and chromium (V I) using a solid waste material as an adsorbent, obtaining successful results which makes this proposal circumscribe into the clean technology program and residues bag

  15. Removal of different fractions of NOM foulants during demineralized water backwashing

    KAUST Repository

    Li, Sheng

    2012-09-01

    The effectiveness of demineralized water backwashing on fouling by different fractions of NOM was investigated in this study. Two types of natural surface water (Schie canal and Biesbosch reservoir) were tested to confirm the improvement of demineralized water backwashing on fouling control, and LC-OCD analysis was conducted on Schie canal water to find out which fraction of NOM was removed with those backwashes. Results derived from natural waters showed that demineralized water backwashing substantially improved UF fouling control. LC-OCD analyses showed both UF permeate and demineralized water backwashes were effective on removing part of biopolymers, but demineralized water is also effective for humic substances and a limited amount of low molecular weight substances. However, based on the LC-OCD results, even demineralized water backwashing is not effective to remove all humic substances and biopolymers rejected on the UF membranes. © 2012 Elsevier B.V. All rights reserved.

  16. Numerical implementation and oceanographic application of the thermodynamic potentials of liquid water, water vapour, ice, seawater and humid air – Part 2: The library routines

    Directory of Open Access Journals (Sweden)

    D. G. Wright

    2010-07-01

    Full Text Available The SCOR/IAPSO1 Working Group 127 on Thermodynamics and Equation of State of Seawater has prepared recommendations for new methods and algorithms for numerical estimation of the the thermophysical properties of seawater. As an outcome of this work, a new International Thermodynamic Equation of Seawater (TEOS–10 was endorsed by IOC/UNESCO2 in June 2009 as the official replacement and extension of the 1980 International Equation of State, EOS-80. As part of this new standard a source code package has been prepared that is now made freely available to users via the World Wide Web. This package includes two libraries referred to as the SIA (Sea-Ice-Air library and the GSW (Gibbs SeaWater library. Information on the GSW library may be found on the TEOS-10 web site (http://www.TEOS-10.org. This publication provides an introduction to the SIA library which contains routines to calculate various thermodynamic properties as discussed in the companion paper. The SIA library is very comprehensive, including routines to deal with fluid water, ice, seawater and humid air as well as equilibrium states involving various combinations of these, with equivalent code developed in different languages. The code is hierachically structured in modules that support (i almost unlimited extension with respect to additional properties or relations, (ii an extraction of self-contained sub-libraries, (iii separate updating of the empirical thermodynamic potentials, and (iv code verification on different platforms and between different languages. Error trapping is implemented to identify when one or more of the primary routines are accessed significantly beyond their established range of validity. The initial version of the SIA library is available in Visual Basic and FORTRAN as a supplement to this publication and updates will be maintained on the TEOS-10 web site.

    1

  17. REMOVING BIOMASS FROM WATER PONDS AND SMALL WATER RESERVOIRS BY USING NON-WOVEN FILTERS

    Directory of Open Access Journals (Sweden)

    Jakub Nieć

    2015-10-01

    Full Text Available Small water bodies, for example garden ponds, play many functions in the environment, including biocenotic, hydrological, climatic, sozological, landfill-creative, and aesthetic. Due to their small size, these reservoirs are sensitive to external and internal factors, they are also a common natural contaminants receivers. Nonwoven filters have been investigated for several years as a useful device for treatment of domestic wastewater pre-treated in a septic tank. The aim of this study was to verify the possibility of using this type of filters for water originating from small water body purification. The effectiveness of filters were tested on the water originating from the garden pond, contained high levels of nutrients and intensive algal bloom. Research was carried out on three filters (each filter consisted of four geotextile TS 20 layers. Basic water quality indicators: total suspended solids, turbidity, COD and BOD5, temperature, pH and dissolved oxygen were measured. The research results can be considered as satisfactory in terms of mechanical treatment (removal of turbidity and total suspended solids. An important positive effect of the filters was the oxygenation of the treated water, which is especially important for fish.

  18. Significantly improving trace thallium removal from surface waters during coagulation enhanced by nanosized manganese dioxide.

    Science.gov (United States)

    Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Jiang, Jin; Wang, Yaan; Wu, Zhengsong

    2017-02-01

    Thallium (Tl) is an element of high toxicity and significant accumulation in human body. There is an urgent need for the development of appropriate strategies for trace Tl removal in drinking water treatment plants. In this study, the efficiency and mechanism of trace Tl (0.5 μg/L) removal by conventional coagulation enhanced by nanosized manganese dioxide (nMnO 2 ) were explored in simulated water and two representative surface waters (a river water and a reservoir water obtained from Northeast China). Experimental results showed that nMnO 2 significantly improve Tl(I) removal from selected waters. The removal efficiency was dramatically higher in the simulated water, demonstrating by less than 0.1 μg/L Tl residual. The enhancement of trace Tl removal in the surface waters decreased to a certain extent. Both adjusting water pH to alkaline condition and preoxidation of Tl(I) to Tl(III) benefit trace Tl removal from surface waters. Data also indicated that competitive cation of Ca 2+ decreased the efficiency of trace Tl removal, resulting from the reduction of Tl adsorption on nMnO 2 . Humic acid could largely low Tl removal efficiency during nMnO 2 enhanced coagulation processes. Trace elemental Tl firstly adsorbed on nMnO 2 and then removed accompanying with nMnO 2 settling. The information obtained in the present study may provide a potential strategy for drinking water treatment plants threatened by trace Tl. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Nanofiltration vs. reverse osmosis for the removal of emerging organic contaminants in water reuse

    KAUST Repository

    Yangali-Quintanilla, Victor

    2011-10-01

    Reverse osmosis (RO) in existing water reuse facilities is a water industry standard. However, that approach may be questioned taking into consideration that "tight" NF can be equal or "better" than RO. NF can achieve the same removals of RO membranes when dealing with emerging organic contaminants (pharmaceuticals, pesticides, endocrine disruptors and others). Experiments using 18 emerging contaminants were performed using membranes NF200 and NF90 at bench-scale units, and for a more complete study, results of NF and RO pilot and full-scale experiments where compared to our experimental results. The removal results showed that NF can remove many emerging contaminants. The average removal by tight NF was 82% for neutral contaminants and 97% for ionic contaminants. The average removal by RO was 85% for neutral contaminants and 99% for ionic contaminants. Aquifer recharge and recovery (ARR) followed by NF can effectively remove emerging contaminants with removals over 90% when loose NF membranes are used.

  20. Interactions of fission product vapours with aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Benson, C G; Newland, M S [AEA Technology, Winfrith (United Kingdom)

    1996-12-01

    Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350{sup o}C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs.

  1. Interactions of fission product vapours with aerosols

    International Nuclear Information System (INIS)

    Benson, C.G.; Newland, M.S.

    1996-01-01

    Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350 o C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs

  2. Water Transport and Removal in PEMFC Gas Flow Channel with Various Water Droplet Locations and Channel Surface Wettability

    Directory of Open Access Journals (Sweden)

    Yanzhou Qin

    2018-04-01

    Full Text Available Water transport and removal in the proton exchange membrane fuel cell (PEMFC is critically important to fuel cell performance, stability, and durability. Water emerging locations on the membrane-electrode assembly (MEA surface and the channel surface wettability significantly influence the water transport and removal in PEMFC. In most simulations of water transport and removal in the PEMFC flow channel, liquid water is usually introduced at the center of the MEA surface, which is fortuitous, since water droplet can emerge randomly on the MEA surface in PEMFC. In addition, the commonly used no-slip wall boundary condition greatly confines the water sliding features on hydrophobic MEA/channel surfaces, degrading the simulation accuracy. In this study, water droplet is introduced with various locations along the channel width direction on the MEA surface, and water transport and removal is investigated numerically using an improved model incorporating the sliding flow property by using the shear wall boundary condition. It is found that the water droplet can be driven to the channel sidewall by aerodynamics when the initial water location deviates from the MEA center to a certain amount, forming the water corner flow in the flow channel. The channel surface wettability on the water transport is also studied and is shown to have a significant impact on the water corner flow in the flow channel.

  3. Removing uranium from drinking water by metal hydroxides and anion-exchange resin

    International Nuclear Information System (INIS)

    Lee, S.Y.; Bondietti, E.A.

    1983-01-01

    Results of bench-scale testing on uranium removal from a natural water that was chosen as a good representative of uranium-bearing waters indicated that conventional coagulant and lime softening treatment removes more than 85 percent of dissolved uranium (83 μg U/L) when an optimum pH and dosage were provided. A strong base anion-exchange column is a recommended option for the treatment of private well waters containing uranium at higher than desirable levels

  4. Development of improved low-cost ceramic water filters for viral removal in the Haitian context

    OpenAIRE

    Guerrero Latorre, Laura; Rusiñol Arantegui, Marta; Hundesa Gonfa, Ayalkibet; Garcia Vallès, Maite; Martínez Manent, Salvador; Joseph, Osnick; Bofill Mas, Silvia; Gironès Llop, Rosina

    2015-01-01

    Household-based water treatment (HWT) is increasingly being promoted to improve water quality and, therefore, health status in low-income countries. Ceramic water filters (CWFs) are used in many regions as sustainable HWT and have been proven to meet World Health Organization (WHO) microbiological performance targets for bacterial removal (24 log); however, the described viral removal efficiencies are insufficient to significantly reduce the associated risk of viral infection. With the object...

  5. Application of carbon nanotube technology for removal of contaminants in drinking water: A review

    International Nuclear Information System (INIS)

    Upadhyayula, Venkata K.K.; Deng, Shuguang; Mitchell, Martha C.; Smith, Geoffrey B.

    2009-01-01

    Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM), and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.

  6. Removal of arsenic from potable water by adsorptive media treatment techniques

    International Nuclear Information System (INIS)

    Yousuf, S.; Khan, S.; Aslam, M.T.; Khan, A.R.

    2012-01-01

    Summary: This study was conducted to investigate the arsenic removal efficiency of different adsorptive media from water. Different naturally occurring materials such as bauxite, plastic clay, plaster of Paris, lime, alum, and alumina etc. were used for the development of media to remove arsenic As/sup +5/ present in the artificially contaminated water. Different ratios of the selected materials were combined and ignited at 9000 C to enhance its arsenic removing efficiency. It was found that the media bauxite, plastic clay, lime (1:1:1) has a maximum removal (99%) of As +5 species from aqueous media and can be used on- site to reduce the arsenic contamination of potable water. Furthermore, the materials used in this experiment were cheaply and abundantly available within the country. The method is very simple and economically viable, for removal of arsenic from potable water. (author)

  7. SiC fibre by chemical vapour deposition on tungsten filament

    Indian Academy of Sciences (India)

    Unknown

    SiC fibre by chemical vapour deposition on tungsten filament ... CMCs), in defence and industrial applications. SiC has attractive ... porosity along with chemical purity. This is lacking .... reactor. Since mercury is very toxic it should be removed.

  8. Oxytetracycline removal from water by novel microbial embedding gel beads

    Science.gov (United States)

    Wu, Nan; Pan, Peng; Zeng, Ming; Wang, Wei; Xu, Chenshan; Zhang, Zongpeng; Liu, Xinyuan; Wang, Yichao

    2018-01-01

    As a common antibiotic in aquatic environment, excessive oxytetracycline (OTC) is urgent to be removed due to its great biological toxicity. Compared with the traditional activated sludge, microbial embedding can enhance the treating efficiency. In this study, novel microbial embedding gel beads were produced with the additional agent of cyclodextrin (CD). Results show that CD could increase the mass transfer of OTC into gel beads, possibly because of its strong affinity for organic matters. In terms of OTC biodegradation, gel beads with CD were comparable to gel beads without CD, while the former’s sucrose removal efficiency was higher than the latter. The biodegradation of OTC only occurred in the presence of sucrose. The respiration test also confirmed these findings. Overall, the produced novel gel beads modified with CD could improve the removal performance of OTC.

  9. Preparation of hydrosol suspensions of elemental and core–shell nanoparticles by co-deposition with water vapour from the gas-phase in ultra-high vacuum conditions

    International Nuclear Information System (INIS)

    Binns, Chris; Prieto, Pilar; Baker, Stephen; Howes, Paul; Dondi, Ruggero; Burley, Glenn; Lari, Leonardo; Kröger, Roland; Pratt, Andrew; Aktas, Sitki; Mellon, John K.

    2012-01-01

    We report a new method to produce liquid suspensions of nanoparticles by co-deposition with water vapour from the gas-phase in ultra-high vacuum (UHV) conditions. The water is injected from outside the vacuum as a molecular beam onto a substrate maintained at 77 K and forms an ice layer with a UHV vapour pressure. Molecular dynamics simulations confirm that the nanoparticles are soft-landed close to the surface of the growing ice layer. We show that the un-agglomerated size distribution within the liquid is similar to the gas-phase size distribution and demonstrate that the inclusion of surfactants in the injected water prevents agglomeration. The method allows the flexibility and tight size control available with gas-phase production methods to be applied to making nanoparticle suspensions with any desired properties. This is important for practical applications, especially in medicine. We have extended the method to include core–shell nanoparticles, in which there is flexible control over the core size and shell thickness and free choice of the material in either. Here, we report the production of suspensions of Cu, Ag and Au elemental nanoparticles and Fe-Au and Fe-Fe-oxide core–shell nanoparticles with diameters in the range 5–15 nm. We demonstrate the power of the method in practical applications in the case of Fe-Fe-oxide nanoparticles, which have a specific absorption rate of an applied oscillating magnetic field that is significantly higher than available Fe-oxide nanoparticle suspensions and the highest yet reported. These will thus have a very high-performance in the treatment of tumours by magnetic nanoparticle hyperthermia.

  10. Non-biological removal of organic pollutants from water

    International Nuclear Information System (INIS)

    Mersmann, A.; Kutzer, S.; Kajszika, H.; Wintrich, H.

    1995-01-01

    Contaminants present in waste water, seepage water and ground water include salts, heavy metals and organic compounds of low biodegradability. This paper considers the wide range of physico-chemical processes available for separation of such compounds from water and points out their optimal and economic range of application. Main subjects are desorption processes (air/steam stripping), adsorption processes (activated carbon, polymeric resins) and membrane separation processes. Alternative water treatment technologies (evaporation, distillation, liquid-liquid-extraction, oxidation, flocculation and precipitation) and combined processes are presented and discussed. (orig.) [de

  11. Treatment techniques for the removal of radioactive contaminants from drinking water

    International Nuclear Information System (INIS)

    Logsdon, Gary S.

    1978-01-01

    Maximum contaminant levels have been set for radioactive contaminants, as required by the Safe Drinking Water Act (PL 93-523). Treatment techniques are available for removing radium and beta-gamma emitters. Presently-used methods of removing radium-226 are precipitative lime softening (80-90% removal) ion exchange softening (95% removal) and reverse osmosis (95% removal). The 5 p Ci/l limit for radium can be met with conventional technology for raw waters in the 5-100 p Ci/l concentration range. Treatment for removal of beta or gamma emitters must be based upon chemical rather than radioactive characteristics of the contaminant. Reverse osmosis can remove a broad spectrum of ions and molecules from water, so it is the process most likely to be used. The maximum contaminant level for beta and gamma radioactivity is an annual dose equivalent to the total body or any organ not to exceed 4 m rem/year. The fate of radionuclides after removal from drinking water should be considered. Presently radium is disposed with other process wastes at softening plants removing radium. Confinement and disposal as a radioactive waste would be very expensive. (author)

  12. Optimization of Photooxidative Removal of Phenazopyridine from Water

    Science.gov (United States)

    Saeid, Soudabeh; Behnajady, Mohammad A.; Tolvanen, Pasi; Salmi, Tapio

    2018-05-01

    The photooxidative removal of analgesic pharmaceutical compound phenazopyridine (PhP) from aqueous solutions by UV/H2O2 system with a re-circulated photoreactor was investigated. Response surface methodology (RSM) was employed to optimize the effect of operational parameters on the photooxidative removal efficiency. The investigated variables were: the initial PhP and H2O2 concentrations, irradiation time, volume of solution and pH. The analysis of variance (ANOVA) of quadratic model demonstrated that the described model was highly significant. The predicted values of the photooxidative removal efficiency were found to be in a fair agreement with experimental values ( R 2 = 0.9832, adjusted R 2 = 0.9716). The model predicted that the optimal reaction conditions for a maximum removal of PhP (>98%) were: initial PhP concentration less than 23 mg L-1, initial concentration of H2O2 higher than 470 mg L-1, solution volume less than 500 mL, pH close to 2 and irradiation time longer than 6 min.

  13. Mo and Ni Removal from Drinking Water Using Zeolitic Tuff from Jordan

    Directory of Open Access Journals (Sweden)

    Khalil M. Ibrahim

    2016-11-01

    Full Text Available Mo and Ni metals could be hazardous in natural waters. The initial Mo and Ni concentration in the sampled domestic drinking water of north Jordan is 550 and 110 μg/L, respectively. The efficiency of using natural faujasite–phillipsite and phillipsite–chabazite tuffs in removing Mo and Ni from contaminated drinking water was tested. Batch experiments using different weights of the adsorbent were conducted at different contact times to determine the optimum conditions. The maximal uptake capacity of Mo from drinking water was equivalent to 440–420 μg/g adsorbent. The maximum removal efficiency of Mo by faujasite–phillipsite, phillipsite–chabazite, and the modified surfactant phillipsite–chabazite tuffs were 80%, 76%, and 78%, respectively. The proportional relationship between contact time and removal efficiency of Ni from water samples was observed. The maximum removal efficiency of Ni by the zeolitic tuffs is up to 90% compared to the original groundwater sample.

  14. Local area water removal analysis of a proton exchange membrane fuel cell under gas purge conditions.

    Science.gov (United States)

    Lee, Chi-Yuan; Lee, Yu-Ming; Lee, Shuo-Jen

    2012-01-01

    In this study, local area water content distribution under various gas purging conditions are experimentally analyzed for the first time. The local high frequency resistance (HFR) is measured using novel micro sensors. The results reveal that the liquid water removal rate in a membrane electrode assembly (MEA) is non-uniform. In the under-the-channel area, the removal of liquid water is governed by both convective and diffusive flux of the through-plane drying. Thus, almost all of the liquid water is removed within 30 s of purging with gas. However, liquid water that is stored in the under-the-rib area is not easy to remove during 1 min of gas purging. Therefore, the re-hydration of the membrane by internal diffusive flux is faster than that in the under-the-channel area. Consequently, local fuel starvation and membrane degradation can degrade the performance of a fuel cell that is started from cold.

  15. Evaluation of the Efficiency of Clay Pots in Removal of Water Impurities

    Directory of Open Access Journals (Sweden)

    K Naddafi , AH Mahvi, S Nasseri, M Mokhtari, H Zeraati

    2005-04-01

    Full Text Available Recently, inexpensive technologies for drinking water supply in small communities are highly considered in developing countries. One of these technologies is the application of ceramic filters that are usually made of diatomaceous earth or clay soil. This research was carried out to determine the efficiency of clay pots (as a filter in removing water impurities. Pilot and the related clay parts were manufactured and its efficiency in removing TDS, hardness, NO3-, color and turbidity was measured by passing water through the clay pipes. The results showed that the clay filters had not the potential to remove hardness, EC, TDS and nitrate of water. However, they showed excellent efficiency in turbidity removal (≥ 90% and could significantly decrease the color of the water (≥ 60%.

  16. Performance of alum and assorted coagulants in turbidity removal of muddy water

    Science.gov (United States)

    Malik, Qasim H.

    2018-03-01

    Coagulation is a primary and cost effective process in water treatment plants. Under optimum conditions, not only it effectively removes turbidity but also results in reduced sludge volume and subsequently minimizes sludge management costs. Highly turbid water from streams, canals, rivers and rain run offs was run through jar test for turbidity removal. The brown water with 250NTU turbidity when coagulated with alum and assorted coagulants proved that maximum turbidity removal was witnessed using alum dose of 0.25 g/l at ph 6 with a sedimentation time of 30 min.

  17. Experimental Investigation on the Material Removal of the Ultrasonic Vibration Assisted Abrasive Water Jet Machining Ceramics

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2017-01-01

    Full Text Available The ultrasonic vibration activated in the abrasive water jet nozzle is used to enhance the capability of the abrasive water jet machinery. The experiment devices of the ultrasonic vibration assisted abrasive water jet are established; they are composed of the ultrasonic vibration producing device, the abrasive supplying device, the abrasive water jet nozzle, the water jet intensifier pump, and so on. And the effect of process parameters such as the vibration amplitude, the system working pressure, the stand-off, and the abrasive diameter on the ceramics material removal is studied. The experimental result indicates that the depth and the volume removal are increased when the ultrasonic vibration is added on abrasive water jet. With the increase of vibration amplitude, the depth and the volume of material removal are also increased. The other parameters of the ultrasonic vibration assisted abrasive water jet also have an important role in the improvement of ceramic material erosion efficiency.

  18. Corrigendum to “Relative humidity effects on water vapour fluxes measured with closed-path eddy-covariance systems with short sampling lines” [Agric. Forest Meteorol. 165 (2012) 53–63

    DEFF Research Database (Denmark)

    Fratini, Gerardo; Ibrom, Andreas; Arriga, Nicola

    2012-01-01

    It has been formerly recognised that increasing relative humidity in the sampling line of closed-path eddy-covariance systems leads to increasing attenuation of water vapour turbulent fluctuations, resulting in strong latent heat flux losses. This occurrence has been analyzed for very long (50 m...... from eddy-covariance systems featuring short (4 m) and very short (1 m) sampling lines running at the same clover field and show that relative humidity effects persist also for these setups, and should not be neglected. Starting from the work of Ibrom and co-workers, we propose a mixed method...... and correction method proposed here is deemed applicable to closed-path systems featuring a broad range of sampling lines, and indeed applicable also to passive gases as a special case. The methods described in this paper are incorporated, as processing options, in the free and open-source eddy...

  19. EFFICIENCY OF DOMESTIC REVERSE OSMOSIS IN REMOVAL OF TRIHALOMETHANES FROM DRINKING WATER

    Directory of Open Access Journals (Sweden)

    S. Mazloomi ، R. Nabizadeh ، S. Nasseri ، K. Naddafi ، S. Nazmara ، A. H. Mahvi

    2009-10-01

    Full Text Available The reaction of disinfectants with natural organic matters existing in water lead to the formation of Disinfection By-Products. Potentially hazardous and carcinogenic characteristics of trihalomethanes (THMs are recognized. Thus removal of THMs or its precursors are necessary for human health. The aim of this study was to study the efficiency of domestic reverse osmosis (RO in removal of trihalomethanes from drinking water. A pilot scale of RO system with Polyamide membrane as Spiral-Wound, Tape wrapping module was used. Feed solution was made by using of pure chloroform. The samples containing chloroform were analyzed using a gas chromatograph equipped with a flame ionization detector. By increasing the flow, the removal rate of chloroform decreased and with declining removal of EC, the removal of chloroform declined too. In this research, at the worst condition, the efficiency of the pilot scale reverse osmosis reached to 80 % removal of chloroform.

  20. Applicability of MIEX(®)DOC process for organics removal from NOM laden water.

    Science.gov (United States)

    Karpinska, Anna M; Boaventura, Rui A R; Vilar, Vítor J P; Bilyk, Andrzej; Molczan, Marek

    2013-06-01

    The aim of this study was to evaluate applicability of ion exchange process for organics removal from Douro River surface water at the intake of Lever water treatment plant using magnetized ion exchange resin MIEX®. Qualitative analysis of the natural organic matter present in the surface water and prediction of its amenability to removal in conventional coagulation process were assessed. Results obtained in MIEX®DOC process kinetic batch experiments allowed determination of ion exchange efficiency in dissolved organic carbon (DOC), UV absorbing organics, and true color removal. The data were compared with the efficiencies of the conventional unit processes for organics removal at Lever WTP. MIEX®DOC process revealed to be more efficient in DOC removal than conventional treatment achieving the efficiencies in the range of 61-91 %, lowering disinfection by-products formation potential of the water. DOC removal efficiency at Lever WTP depends largely on the raw water quality and ranges from 28 % for water of moderated quality to 89 % of significantly deteriorated quality. In this work, MIEX®DOC process was also used as a reference method for the determination of contribution of anionic fraction to dissolved organic matter and selectivity of the unit processes at Lever WTP for its removal.

  1. Efficiency of lead removal from drinking water using cationic resin Purolite

    Directory of Open Access Journals (Sweden)

    Ashour Mohammad Merganpour

    2015-01-01

    Full Text Available Background: Today, issues such as water shortage, difficulties and costs related to supplying safe water, and anomalous concentrations of heavy metals in groundwater and surface water resources, doubled the necessity of access to technical methods on removing these pollutants from water resources. Methods: In this lab study, cationic resin Purolite S-930 (with co-polymer styrene di-vinyl benzene structure was used for lead removal from drinking water containing up to 22 μg/L. Using statistical analysis and designing a full factorial experiment are the most important effective parameters on lead removal obtained through ion exchange process. Results: Analysis of response and interaction parameters of ion exchange showed that the resin column height has maximum and pH value has minimum effect on the efficiency of lead removal from aquatic environment. Trinary interaction of “effective size, flow rate, resin column high” has the most important for lead removal efficiency in this system. So the maximum efficiency was obtained at the mesh = 40, bed height =1.6 meter, and pH= 6.5. At the best operation conditions, ability to remove 95.42% of lead concentration can be achieved. Conclusion: Using the resin Purolite S-930 during 21-day service with 91.12% of mean lead removal ratio from drinking water is an economic and technical feasibility.

  2. Removal of heavy metals from water with forest based materials

    Science.gov (United States)

    James D. McSweeny; Roger M. Rowell; George C. Chen; Thomas L. Eberhardt; Soo-Hong Min

    2006-01-01

    For 1.5 to 2.5 billion people in the world, clean water is a critical issue (Lepkowski 1999). In the U.S., it is estimated that 90% of all Americans live within 10 miles of a body of contaminated water (Hogue, 2000). The development of filters to clean our water supply is big business. It is estimated that global spending on filtration (including dust collectors, air...

  3. Oil adsorbing package, also procedure to remove oil from a water surface

    Energy Technology Data Exchange (ETDEWEB)

    1971-05-01

    A method is given to remove oil from water to prevent water pollution. Use is made of an oil-adsorbing packet having a specific gravity which is lower than the specific gravity of water. The hull is manufactured from any material which is not a water-insoluble nonpolar material. The hull is partly permeable to water and encloses a solid oil-adsorbing compound having a large adsorbing surface. (10 claims)

  4. Calcium carbonate in the removal of iron and lead from dilute waste water

    Energy Technology Data Exchange (ETDEWEB)

    Hautala, E; Randall, J; Goodban, A; Waiss, A Jr

    1977-01-01

    The utility of powdered CaCO/sub 3/ in the removal of lead and iron from dilute aqueous waste waters has been demonstrated and the results successfully applied to treat industrial waste water from a lead battery plant. The reclaimed water is suitable for recycling to the plant and is now being utilized with consequent economic advantages.

  5. Removal of trace organics from water by pervaporation : a technical and economic analysis

    NARCIS (Netherlands)

    Nijhuis, Herman Henk

    1990-01-01

    Volatile organic hydrocarbons in ground water, surface water or waste water are a continuous threat to the public health. Often traditional purification techniques cannot be applied to remove these components from aqueous solutions. In this thesis the technical and economic feasibility of

  6. ETV REPORT: REMOVAL OF CHEMICAL CONTAMINANTS IN DRINKING WATER — PALL/KINETICO PUREFECTA DRINKING WATER TREATMENT SYSTEM

    Science.gov (United States)

    The Pall/Kinetico Purefecta™ POU drinking water treatment system was tested for removal of aldicarb, benzene, cadmium, carbofuran, cesium, chloroform, dichlorvos, dicrotophos, fenamiphos, mercury, mevinphos, oxamyl, strontium, and strychnine. The Purefecta™ employs several compon...

  7. The mechanical vapour compression process applied to seawater desalination

    International Nuclear Information System (INIS)

    Murat, F.; Tabourier, B.

    1984-01-01

    The authors present the mechanical vapour compression process applied to sea water desalination. As an example, the paper presents the largest unit so far constructed by SIDEM using this process : a 1,500 m3/day unit installed in the Nuclear Power Plant of Flamanville in France which supplies a high quality process water to that plant. The authors outline the advantages of this process and present also the serie of mechanical vapour compression unit that SIDEM has developed in a size range in between 25 m3/day and 2,500 m3/day

  8. Study of Phytoremediation Capability in Sulfate Removal from Water

    Directory of Open Access Journals (Sweden)

    Milad Tafazoli

    2014-07-01

    Full Text Available Phytoremediation is known as a pollutants method with low cost, without operational complexity, with low energy consumption and no need for sludge disposal. In this study, hydroponic cultivation was chosen for estimation of sulfate removal as a significant sulfur compound in effluents on two fenny plants: pampas grass and bamboo.In this case, the plants were examined under two different retention times and after determining the optimum time (7 days, the main experiments were done for evaluating the plants removal efficiency and sulfate mass absorbance by plants. For better analysis, T-Test and ANOVA with significant influence (p < 0.05% were also done. Finally, the removal efficiency in pampas grass for all concentrations of 50, 200, 300, 600, 900, 1200, 1500 and 3000 mg/L were 44, 36, 34.22, 30.55, 15.93, 9.72, 7.77 and 4.44 percent, respectively, which were up to two times higher for the bamboos.

  9. The effective removal method of copper and cyanide in waste water of metal plating factories

    International Nuclear Information System (INIS)

    Jae, Won Mok; Hong, Zong Doo; Kim, Myun Sup

    1988-01-01

    To investigate the effective removal method of cooper and cyanide compounds in metal plating waste water, removal ratio of cooper and cyanide compounds in solution are measured with varying pH, concentration and contact time. As results of the present experiment, cyanide compounds in the solution are removed to 0.03mg/l or less with 5% NaOCl solution. The present result is satisfied to environmental disposal standards. The removal ratio against pH values show 99% over pH8. As results of neutral precipitation method, copper including solution are removed to 99% at pH8 in short time. The removal ratios of cyanide mixed copper solution against pH values show high efficiency(over 95%) at pH8 and 11 and removal ratios are decreased at pH10.(Author)

  10. INTERACTIVE WORKSHOP ON ARSENIC REMOVAL FROM DRINKING WATER

    Science.gov (United States)

    In 2005, EPA's Office of Water and Office of Research and Development collaborated to present eleven arsenic training events. The workshops provided in-depth treatment technology training to help those affected; state drinking water staff, design engineers, system owners and cert...

  11. Granular activated carbon to remove agrichemicals from water

    Science.gov (United States)

    Many growers capture and reuse irrigation water in ponds or flood irrigation tanks. Agrichemical residues can potentially build up over time and affect future crops irrigated with residue-laden water. One key chemical of concern is paclobutrazol, which is very persistent, with a half-life of around ...

  12. Removing Dissolved Silica from Waste Water with Catechol and Active Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Sasan, Koroush [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanoscale Sciences Dept.; Brady, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Energy Program; Krumhansl, James L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geosciences Dept.; Nenoff, Tina M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Physical Chemical and Nano Sciences Center

    2017-01-01

    Fresh water scarcity is going to be a global great challenge in the near future because of the increasing population. Our water resources are limited and, hence, water treatment and recycling methods are the only alternatives for fresh water procurement in the upcoming decades. Water treatment and recycling methods serve to remove harmful or problematic constituents from ground, surface and waste waters prior to its consumption, industrial supply, or other uses. Scale formation in industrial and domestic installations is still an important problem during water treatment. In water treatment, silica scaling is a real and constant concern for plant operations. The focus of this study is on the viability of using a combination of catechol and active carbon to remove dissolved silica from concentrated cooling tower water (CCTW). Various analytical methods, such as ICP-MS and UV-vis, were used to understand the structure-property relationship between the material and the silica removal results. UV-Vis indicates that catechol can react with silica ions and form a silica-catecholate complex. The speciation calculation of catechol and silica shows that catechol and silica bind in the pH range of 8 – 10; there is no evidence of linkage between them in neutral and acidic pHs. The silica removal results indicate that using ~4g/L of catechol and 10g/L active carbon removes up to 50% of the dissolved silica from the CCTW.

  13. Coagulation effectiveness of graphene oxide for the removal of turbidity from raw surface water.

    Science.gov (United States)

    Aboubaraka, Abdelmeguid E; Aboelfetoh, Eman F; Ebeid, El-Zeiny M

    2017-08-01

    This study presents the performance of graphene oxide (GO) as a coagulant in turbidity removal from naturally and artificially turbid raw surface water. GO is considered an excellent alternative to alum, the more common coagulant used in water treatment processes, to reduce the environmental release of aluminum. Effects of GO dosage, pH, and temperature on its coagulation ability were studied to determine the ideal turbidity removal conditions. The turbidity removal was ≥95% for all levels of turbid raw surface water (20, 100, and 200 NTU) at optimum conditions. The role of alkalinity in inducing turbidity removal by GO coagulation was much more pronounced upon using raw surface water samples compared with that using artificially turbid deionized water samples. Moreover, GO demonstrated high-performance removal of biological contaminants such as algae, heterotrophic bacteria, and fecal coliform bacteria by 99.0%, 98.8% and 96.0%, respectively, at a dosage of 40 mg/L. Concerning the possible environmental release of GO into the treated water following filtration process, there was no residual GO in a wide range of pH values. The outcomes of the study highlight the excellent coagulation performance of GO for the removal of turbidity and biological contaminants from raw surface water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Nanoparticle Zere-valent Iron Affect on As (V Removal from Drinking Water

    Directory of Open Access Journals (Sweden)

    Hamed Koohpayehzadeh

    2012-10-01

    Full Text Available Arsenic which is present in the underground and surface water is one of the most toxic elements threating human health and animals. Arsenic has been removed in different type of ways. In this study Arsenic removal from drinking water and its decreasing rates were investigated by NZVI (nanoparticle zerovalent iron to standard limit (I.e.  0.01 mg/lit . The tests were conducted on reactor containing 100 ml water containing 1mg/L. Arsenic by virtue of Batch method. The mixture was executed in mixing was done an Oultrasnic device in order to have better mixture and complete distribution of nanoparticles in water. Then the arsenic was