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Sample records for clay water systems

  1. Water Absorbing Plantation Clay for Vertical Greenery System

    Directory of Open Access Journals (Sweden)

    Yu Lih-Jiun

    2016-01-01

    Full Text Available With the arises of environmental conscious, the usage of vertical garden system has become more popular in urban cities. Citizens can enjoys the benefits of energy and cost saving besides ornamental effect. More investigations have been conducted on green facades led to the cities ecological enhancement.However, limited plants species can be planted for green facades systems as this system does not provide sufficient soil and nutrients for common plants. Alternative plantation methods such as planted box and felt system required additional maintenance attention. The idea of using clay composite which consists of nutritious soil, water absorbing polymer and flexible cement clay potentially become alternative vertical greenery systems that offers economic and sustainable plantation platform for more variety of plants.The fabricating of clay composite involved three processes, they are: mixing, moulding and drying. Physical properties characterisation (density, pH, compression test, aging test and water immersion test were tested on the dried fabricated clay composite to ensure their sustainability in tropical climate. The results showed that clay composite with 1.5 wt% of cement and 0.3 wt% superabsorbent polymer shows optimum water absorbing properties. This system are expected to enable more agriculture activities in urban living.

  2. Applications of fractional calculus to diffusion transport in clay-water system

    International Nuclear Information System (INIS)

    The analysis of the low-frequency conductivity spectra of the clay-water mixtures is presented. The conductivity spectra for samples at different water content values are shown to collapse to a single master curve when appropriately rescaled. The frequency dependence of the conductivity is shown to follow the power-law with the exponent η=0,67 before reaching the frequency-independent part. It is argued that the observed conductivity dispersion is a consequence of the anomalously diffusing ions in the clay-water system. The fractional Langevin equation is then used to describe the stochastic dynamics of the single ion. (author)

  3. Structural Investigation of Alkali Activated Clay Minerals for Application in Water Treatment Systems

    Science.gov (United States)

    Bumanis, G.; Bajare, D.; Dembovska, L.

    2015-11-01

    Alkali activation technology can be applied for a wide range of alumo-silicates to produce innovative materials with various areas of application. Most researches focuse on the application of alumo-silicate materials in building industry as cement binder replacement to produce mortar and concrete [1]. However, alkali activation technology offers high potential also in biotechnologies [2]. In the processes where certain pH level, especially alkaline environment, must be ensured, alkali activated materials can be applied. One of such fields is water treatment systems where high level pH (up to pH 10.5) ensures efficient removal of water pollutants such as manganese [3]. Previous investigations had shown that alkali activation technology can be applied to calcined clay powder and aluminium scrap recycling waste as a foam forming agent to create porous alkali activated materials. This investigation focuses on the structural investigation of calcined kaolin and illite clay alkali activation processes. Chemical and mineralogical composition of both clays were determined and structural investigation of alkali activated materials was made by using XRD, DTA, FTIR analysis; the microstructure of hardened specimens was observed by SEM. Physical properties of the obtained material were determined. Investigation indicates the essential role of chemical composition of the clay used in the alkali activation process, and potential use of the obtained material in water treatment systems.

  4. Water Absorbing Plantation Clay for Vertical Greenery System

    OpenAIRE

    Yu Lih-Jiun; De Vera Santos Aegil; Tan Khang-Wei; Tawawneh Mou’ad A

    2016-01-01

    With the arises of environmental conscious, the usage of vertical garden system has become more popular in urban cities. Citizens can enjoys the benefits of energy and cost saving besides ornamental effect. More investigations have been conducted on green facades led to the cities ecological enhancement.However, limited plants species can be planted for green facades systems as this system does not provide sufficient soil and nutrients for common plants. Alternative plantation methods such as...

  5. Boom clay pore water chemistry

    International Nuclear Information System (INIS)

    In Belgium, geological disposal in clay is the primary option for the isolation of high-level radioactive waste and spent fuel from the biosphere. The Boom Clay is studied as the potential host rock for methodological studies on the geological disposal of radioactive waste. It is present under the facilities of the SCK-CEN at Mol, at a depth of 190 to 293 m. The current R and D programme focuses on the feasibility and safety of radioactive waste disposal in the Boom Clay. In this framework, a detailed characterisation of the clay is performed (mechanical, physico-chemical and hydrogeological properties, variability, role of organic matter,...). In addition, high priority is given to the understanding of the basic phenomena which control the retention o f radionuclides in the clay. Therefore, it is very important to characterise and understand the pore water composition in the host rock. All the available information from previous studies on the Boom Clay pore water chemistry was synthesise d in a 'state of the art' report, status 2004. This report describes the pore water sampling and analytical techniques, the results, and interpretation of a series of studies carried out in-situ in the HADES URF and in the laboratories. The objective of this study was to evaluate the most reliable technique(s) to obtain representative pore water samples, to determine the variation of the pore water composition in the Boom Clay, to present a coherent geochemical model for explaining the mechanisms controlling the Boom Clay pore water composition, and to propose a reference pore water composition to be used in the laboratory experiments, for speciation calculations, and for assessments of perturbation that might influence the Boom Clay pore water. The main conclusions will be presented here. (authors)

  6. Active containment systems incorporating modified pillared clays

    Energy Technology Data Exchange (ETDEWEB)

    Lundie, P. [Envirotech (Scotland) Ltd., Aberdeen (United Kingdom)]|[Environmental Resource Industries Disposal Pty Ltd., Perth (Australia); McLeod, N. [Envirotreat Ltd., Kingswinford (United Kingdom)

    1997-12-31

    The application of treatment technologies in active containment systems provides a more advanced and effective method for the remediation of contaminated sites. These treatment technologies can be applied in permeable reactive walls and/or funnel and gate systems. The application of modified pillared clays in active containment systems provides a mechanism for producing permeable reactive walls with versatile properties. These pillared clays are suitably modified to incorporate reactive intercalatants capable of reacting with both a broad range of organic pollutants of varying molecular size, polarity and reactivity. Heavy metals can be removed from contaminated water by conventional ion-exchange and other reactive processes within the clay structure. Complex contamination problems can be addressed by the application of more than one modified clay on a site specific basis. This paper briefly describes the active containment system and the structure/chemistry of the modified pillared clay technology, illustrating potential applications of the in-situ treatment process for contaminated site remediation.

  7. Nitrogen and Phosphorus Removal in the Recirculating Aquaculture System with Water Treatment Tank containing Baked Clay Beads and Chinese Cabbage

    Directory of Open Access Journals (Sweden)

    Aeknarin Thanakitpairin

    2014-01-01

    Full Text Available This research aims to describe the nitrogen and phosphorus removal in Recirculating Aquaculture System (RAS by crop plants biomass production. The 3 experiment systems consisted of 1 treatment (fish tank + baked clay beads + Chinese cabbage and 2 controls as control-1 (fish tank only and control-2 (fish tank + baked clay beads, were performed. With all experimental RAS, Nile tilapia (Oreochromis niloticus was cultured at 2 kg/m3 density. The baked clay beads (8-16 mm in diameter were filled as a layer of 10 cm in the water treatment tank of control-2. While in the treatment tank, Chinese cabbage (Brassica pekinensis was planted at 334 plants/m2 in baked clay beads layer. During 35 days of experiment, the average fish wet-weight in control-1, control-2 and treatment systems increased from 16.31±1.49, 15.18±1.28 and 11.31±1.49 g to 29.43±7.06, 28.65±3.12 and 27.20±6.56 g, respectively. It was found that the growth rate of 0.45±0.15 g-wet weight/day in a treatment tank was higher than in those 2 controls, which were rather similar at 0.37±0.16 and 0.38±0.05 g-wet weight/day, respectively. The fish survival rate of all experimental units was 100%. The average Chinese cabbage wet-weight in treatment system increased from 0.15±0.02 g to 1.00±0.38 g. For water quality, all parameters were within the acceptable range for aquaculture. The assimilation inorganic nitrogen in a treatment tank showed a slower rate and lower nitrite accumulation relative to those in control tanks. The nitrogen and phosphorus balance analysis illustrated that most of the nitrogen and phosphorus input in all systems was from feed (82-87% and 21-87% while at the final day of experiments, nitrogen and phosphorus in tilapia culture revealed at 15-19% and 4-13%. The accumulation of nitrogen and phosphorus in the water, up to 56% and 70%, was found in control-1 while water in the tank with baked clay beads had substantial lower nitrogen and phosphorus concentration. The

  8. Nitrogen and Phosphorus Removal in the Recirculating Aquaculture System with Water Treatment Tank containing Baked Clay Beads and Chinese Cabbage

    OpenAIRE

    Aeknarin Thanakitpairin; Wiboonluk Pungrasmi; Sorawit Powtongsook

    2014-01-01

    This research aims to describe the nitrogen and phosphorus removal in Recirculating Aquaculture System (RAS) by crop plants biomass production. The 3 experiment systems consisted of 1 treatment (fish tank + baked clay beads + Chinese cabbage) and 2 controls as control-1 (fish tank only) and control-2 (fish tank + baked clay beads), were performed. With all experimental RAS, Nile tilapia (Oreochromis niloticus) was cultured at 2 kg/m3 density. The baked clay beads (8-16 mm in diameter) were fi...

  9. Clay-Bacteria Systems and Biofilm Production

    Science.gov (United States)

    Steiner, J.; Alimova, A.; Katz, A.; Steiner, N.; Rudolph, E.; Gottlieb, P.

    2007-12-01

    Soil clots and the aerosol transport of bacteria and spores are promoted by the formation of biofilms (bacteria cells in an extracellular polymeric matrix). Biofilms protect microorganisms by promoting adhesion to both organic and inorganic surfaces. Time series experiments on bacteria-clay suspensions demonstrate that biofilm growth is catalyzed by the presence of hectorite in minimal growth media for the studied species: Gram negatives (Pseudomonas syringae and Escherichia coli,) and Gram positives (Staphylococcus aureus and Bacillus subtilis). Soil organisms (P. syringae, B. subtilis) and organisms found in the human population (E. coli, S. aureus) are both used to demonstrate the general applicability of clay involvement. Fluorescent images of the biofilms are acquired by staining with propidium iodide, a component of the BacLightTM Live/Dead bacterial viability staining kit (Molecular Probes, Eugene, OR). The evolving polysaccharide-rich biofilm reacts with the clay interlayer site causing a complex substitution of the two-water hectorite interlayer with polysaccharide. The result is often a three-peak composite of the (001) x-ray diffraction maxima resulting from polysaccharide-expanded clays and an organic-driven contraction of a subset of the clays in the reaction medium. X-ray diffractograms reveal that the expanded set creates a broad maximum with clay subsets at 1.84 nm and 1.41 nm interlayer spacings as approximated by a least squares double Lorentzian fit, and a smaller shoulder at larger 2q, deriving from a contraction of the interlayer spacing. Washing with chlorox removes organic material from the contracted clay and creates a 1-water hectorite single peak in place of the double peak. The clay response can be used as an indirect indicator of biofilm in an environmental system.

  10. A possible role of fluctuating clay-water systems in the production of ordered prebiotic oligomers

    Science.gov (United States)

    Lahav, N.; White, D. H.

    1980-01-01

    A model is proposed for the intermediate stages of prebiotic evolution, based on the characteristics of the adsorption and condensation of amino acids and nucleotides on the surface area of clay minerals in a fluctuating environment. Template replication and translation of adsorbed oligonucleotides and catalytic effects by peptide products on further condensation are proposed, due to specific properties of hypohydrous clay surfaces as well as the biomolecules themselves. Experimental evidence supports some of the proposed interactions, and all of them can be tested experimentally.

  11. Impact factors on the structuration and the rheological behavior of the clay-water system for smectite dispersions

    International Nuclear Information System (INIS)

    Smectite are swelling clays widely used in industry. Their mechanical properties are unequal according to their mineralogical and physico-chemical characteristics. The aim of this study is to improve the knowledge of the interlayer cation impact on the structure built by the smectite-water system according to the concentration. Homo-ionic (Na+ et Ca2+) and bi-ionic systems are observed. This study cross checks mineralogical methods, physicochemical analysis and broad range of rheometric tests. At low concentration (less than 60 g/l) the calcium dispersions are shear thinning and few viscous due to the layer association in huge deformable flocks. The sodium smectite layers are dispersed; the dispersions are highly viscous. The lowest viscosity is detected for mix of 20 % of sodium smectite and 80 % of calcium smectite. At higher concentration (60 to 100 g/l), the yield stress and viscoelastic properties are studied by creep-recovery tests, oscillatory tests and imposed shear step. At the liquid state, the flow is first heterogeneous with a shear banding effect then homogeneous. The results make it possible to define the concentration area characteristic of each mechanical behavior (viscosity, shear thinning and yield stress) according to the saturation cation. The thixotropic properties are characterized with de-structuring-restructuring tests. Two kinetics are determined. Finally we realize a data base with 12 natural and industrial bentonite. The rheograms would be efficient to differentiate the natural calcium bentonite (Newtonian law), natural sodium bentonite (Herschel-Bulkley law) and activated calcium bentonite (Bingham law). (author)

  12. Clay-biodegradable polymer combination for pollutant removal from water

    Directory of Open Access Journals (Sweden)

    M. F. Mohd Amin

    2015-09-01

    Full Text Available In this study, a new treatment alternative is investigated to remove micropollutants from wastewater effectively and in a more cost-effective way. A potential solution is the use of clay in combination with biodegradable polymeric flocculants. Flocculation is viewed as the best method to get the optimum outcome from the combination of clay with starch. Clay is naturally abundantly available and relatively inexpensive compared to the conventional adsorbents used. Experimental studies were carried out with four different clays to select the best clay for further optimisation. The atrazine removal achieved is in the range of 10–99 % based on the clay concentration of 10–50 g L−1. Optimisation of the best clay performer leads towards atrazine reduction of > 99 % with a dosage of 100 mg L−1. The best and underperforming clays were then tested in other experiments with the addition of cationic starch flocculants. In this experiment, the addition of a polymer increased the atrazine removal for the underperforming clay to 46 % with only 10 mg L−1 clay dosages. The clay flocculation test was also performed to test the flocculation efficiency of clays by the polymer. Approximately 80–84 % of the clay is flocculated, which shows exceptional flocculation efficiency in removing both clays and atrazine from the water matrices.

  13. Water Retention Curves of Opalinus Clay

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M. V.; Romero, F. J.

    2012-11-01

    The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry

  14. The systems containing clays and clay minerals from modified drug release: a review.

    Science.gov (United States)

    Rodrigues, Luís Alberto de Sousa; Figueiras, Ana; Veiga, Francisco; de Freitas, Rivelilson Mendes; Nunes, Lívio César Cunha; da Silva Filho, Edson Cavalcanti; da Silva Leite, Cleide Maria

    2013-03-01

    Clays are materials commonly used in the pharmaceutical industry, either as ingredients or as active ingredients. It was observed that when they are administered concurrently, they may interact with drugs reducing their absorption. Therefore, such interactions can be used to achieve technological and biopharmaceutical advantages, regarding the control of release. This review summarizes bibliographic (articles) and technological (patents) information on the use of systems containing clays and clay minerals in modified drug delivery. In this area, formulations such natural clay, commercial clay, synthetic clay, composites clay-polymers, nanocomposites clay-polymers, films and hidrogels composites clay-polymers are used to slow/extend or vectorize the release of drugs and consequently they increase their bioavailability. Finally, this review summarizes the fields of technology and biopharmaceutical applications, where clays are applied.

  15. Studies on Tagged Clay Migration Due to Water Movement

    International Nuclear Information System (INIS)

    55Fe-tagged clay minerals, produced by hydrothermal synthesis, serve to clarify the question whether clay migration or clay formation in situ is the predominating mechanism in the Bt-development of Parabraunerde (sol brun lessive, grey brown podsolic, hapludalf, dernopodsol). They further indicate the possibilities of clay transportation caused by water percolation. Suitable experimental approaches, such as thin-layer chromatography and autoradiography, translocation tests in columns filled with monotypical textural fractions or with undisturbed soil profiles, and synchronous hydrothermal treatment of 55Fe-con raining material from different horizons of Parabraunerde, to reveal the specific readiness of the different profile zones for 55Fe-clay production, are described. The possibilities of clay percolation are discussed. (author)

  16. The ternary system U(VI) / humic acid / Opalinus Clay

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Claudia

    2013-07-23

    The storage of nuclear waste in deep geological formations is discussed worldwide as the main strategy for nuclear waste management. To ensure the confinement of the nuclear waste, a multiple barrier system which consists of engineered, geo-engineered, and geological barriers will be applied. Thereby, in Germany the definition of the isolating rock zone represents an important safety function indicator. Clay rock is internationally investigated as potential host rock for a repository and represents a part of the geological barrier. In the present work, the natural clay rock Opalinus Clay from the Mont Terri rock laboratory, Switzerland, was studied. In Germany, the direct disposal of the spent nuclear fuel without the reprocessing of the spent fuel is preferred. In case of water ingress, radionuclides can be released from the nuclear waste repository into its surroundings, namely the host rock of the repository. Humic acids, ubiquitous in nature, can be found associated with the inorganic components in natural clay rock (1.5 x 10{sup -3} wt.% in Opalinus Clay). They can be released under certain conditions. Due to their variety of functional groups, humic acids are very strong complexing agents for metal ions. They have inherent redox abilities and a colloidal conformation in solution. Because of these characteristics, humic acids can affect the mobility of metal ions such as actinides. Furthermore, in the near-field of a repository elevated temperatures have to be considered due to the heat production resulting from the radioactive decay of the various radionuclides in the nuclear waste. This work focuses on the interaction of uranium, as main component of spent nuclear fuel, with Opalinus Clay and studies the influence of humic acid and elevated temperature on this interaction. Thus, the collected sorption and diffusion data are not only relevant for safety assessment of nuclear waste repositories but also for any clay-containing system present in the environment

  17. Hydration states of clays followed by water and hydroxyls vibrational analyses in the near infrared: application to saponite and bentonite systems

    International Nuclear Information System (INIS)

    The study of the feasibility of a deep geological disposal facility conducted by ANDRA - the French national radioactive waste management agency -, requires the knowledge of water status and water content in clays. Thanks to an original lab-built device coupling vibrational spectroscopies and water adsorption isotherms, adsorbed water and clay's structure are described quantitatively and qualitatively. A multidisciplinary approach allows the description of hydration mechanisms and water molecules network in the inter lamellar space of synthetic saponites. The effects of density and nature of inter-foliar cations and the influence of temperature on hydration are presented. Using mechanisms and important parameters established on saponites, hydration of bentonite MX80 is carried out. In order to describe and quantify simultaneously two different water states, a simple but relevant method of spectra analysis was developed. (author)

  18. Extraction of Water Treatment Coagulant from Locally Abundant Kaolin Clays

    OpenAIRE

    Fidelis Chigondo; Benias Chomunorwa Nyamunda; Vuyo Bhebhe

    2015-01-01

    Rapid industrialisation is contributing to water pollution. There is a need to identify cheaper and efficient methods of removing contaminants as the demand for clean water rises. A study is carried out to investigate the extraction of alum from locally abundant kaolin clays using sulphuric acid. Alum is a coagulant that is used for raw water treatment. The kaolin clay and alum were characterized by Fourier transformation infrared spectroscopy (FTIR). The effects of particle size, calcination...

  19. Mechanical dispersion of clay from soil into water: readily-dispersed and spontaneously-dispersed clay

    Science.gov (United States)

    Czyż, Ewa A.; Dexter, Anthony R.

    2015-01-01

    A method for the experimental determination of the amount of clay dispersed from soil into water is described. The method was evaluated using soil samples from agricultural fields in 18 locations in Poland. Soil particle size distributions, contents of organic matter and exchangeable cations were measured by standard methods. Sub-samples were placed in distilled water and were subjected to four different energy inputs obtained by different numbers of inversions (end-over-end movements). The amounts of clay that dispersed into suspension were measured by light scattering (turbidimetry). An empirical equation was developed that provided an approximate fit to the experimental data for turbidity as a function of number of inversions. It is suggested that extrapolation of the fitted equation to zero inversions enables the amount of spontaneously-dispersed clay to be estimated. This method introduces the possibility of replacing the existing subjective, qualitative method of determining spontaneously-dispersed clay with a quantitative, objective method. Even though the dispersed clay is measured under saturated conditions, soil samples retain a `memory' of the water contents at which they have been stored.

  20. Extraction of Water Treatment Coagulant from Locally Abundant Kaolin Clays

    Directory of Open Access Journals (Sweden)

    Fidelis Chigondo

    2015-01-01

    Full Text Available Rapid industrialisation is contributing to water pollution. There is a need to identify cheaper and efficient methods of removing contaminants as the demand for clean water rises. A study is carried out to investigate the extraction of alum from locally abundant kaolin clays using sulphuric acid. Alum is a coagulant that is used for raw water treatment. The kaolin clay and alum were characterized by Fourier transformation infrared spectroscopy (FTIR. The effects of particle size, calcination temperature, calcination time, acid-kaolin clay ratio, acid concentration, leaching temperature, and leaching time on extraction efficiency were investigated. The optimum leaching conditions for the calcined kaolin clay were found to be particle size 100 µm, acid-kaolin clay weight ratio 6 : 1, acid concentration 4 M, leaching temperature 100°C, and leaching time 90 min. Under optimised conditions, 66.95% (w/w aluminum sulphate was extracted. The results showed that sulphuric acid could be used on a large scale to extract alum from kaolin clay. The extracted alum showed similar structural and physical characteristics compared with commercial alum. A dosage of 40 mg/L of the extracted alum showed effective coagulant properties with a great potential of treating raw water.

  1. Estimation of soil clay content from hygroscopic water content measurements

    OpenAIRE

    Wuddivira, Mark N.; Robinson, David A.; Lebron, Inma; Brechet, Laëtitia; Atwell, Melissa; De Caires, Sunshine; Oatham, Michael; Jones, Scott B.; Abdu, Hiruy; Verma, Aditya K.; Tuller, Markus

    2012-01-01

    Soil texture and the soil water characteristic are key properties used to estimate flow and transport parameters. Determination of clay content is therefore critical for understanding of plot-scale soil heterogeneity. With increasing interest in proximal soil sensing, there is the need to relate obtained signals to soil properties of interest. Inference of soil texture, especially clay mineral content, from instrument response from electromagnetic induction and radiometric methods is of subst...

  2. Clay mineral liner system for leachates containing organic contaminants

    OpenAIRE

    Sreedharan, Vandana; Sivapullaiah, PV

    2011-01-01

    A conventional liner with a good performance against inorganic contaminants with a minimal hydraulic conductivity does not usually perform well for retention/removal of leachates containing organic contaminants. Organic modification of clay can render the naturally organophobic clay tobe organophilic. Incorporation of modified organo clay along with unmodified inorganic clay in liner systems can overcome the inherent incompatibility of conventional liners to organic contaminants and can incre...

  3. Water diffusion through compacted clays analyzed by neutron scattering and tracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Sanchez, F

    2007-11-15

    Clay minerals are aluminium phyllosilicates, mostly products of the chemical alteration and mechanical breakdown of igneous and metamorphic rocks. Their physical and chemical properties can be directly related to their layered, fine-grained (large surface area) structure. These properties such as large water retention, low hydraulic conductivity, heat resistance and ionic exchange capacities, make clays ideal for many different applications, e.g. as sealing material for the underground disposal of radioactive waste. The long-term disposal of radioactive waste in an underground geological repository is based on a multibarrier concept. In the barrier of highly compacted clay, water is intercalated and confined between the clay layers. The narrow pores are responsible that under natural hydraulic gradients, molecular diffusion through water is the dominant transport mechanism for released radionuclides. The properties of water at the water-clay interface differ from that of bulk water. Therefore, a good and deep understanding of the water structure and dynamics in compacted clay systems is fundamental. This knowledge is the base for the progressing research about transport of pollutants through the compacted clays and argillaceous rock of radioactive waste barriers. This study focusses on four different types of pure clays, two of them charged, namely montmorillonite and illite (both in a Na and Ca form), and two uncharged, namely kaolinite and pyrophyllite. Their structural differences result in a significantly different behaviour in contact with water. In case of montmorillonite, water is located in between particles and in the interlayer space. In illite, water is found only in between particles, because the interlayer surfaces are tightly linked by potassium cations. The layers of kaolinite and pyrophyllite are uncharged and, consequently, water is located only in between particles. The clay powders were compacted to reach a high bulk dry density of about 1.9 g

  4. Quantification of Water Content Across a Cement-clay Interface Using High Resolution Neutron Radiography

    Science.gov (United States)

    Shafizadeh, A.; Gimmi, T.; Van Loon, L.; Kaestner, A.; Lehmann, E.; Maeder, U. K.; Churakov, S. V.

    In many designs for radioactive waste repositories, cement and clay will come into direct contact. The geochemical contrast between cement and clay will lead to mass fluxes across the interface, which consequently results in alteration of structural and transport properties of both materials that may affect the performance of the multi-barrier system. We present an experimental approach to study cement-clay interactions with a cell to accommodate small samples of cement and clay. The cell design allows both in situ measurement of water content across the sample using neutron radiography and measurement of transport parameters using through-diffusion tracer experiments. The aim of the high-resolution neutron radiography experiments was to monitor changes in water content (porosity) and their spatial extent. Neutron radiographs of several evolving cement-clay interfaces delivered quantitative data which allow resolving local water contents within the sample domain. In the present work we explored the uncertainties of the derived water contents with regard to various input parameters and with regard to the applied image correction procedures. Temporal variation of measurement conditions created absolute uncertainty of the water content in the order of ±0.1 (m3/m3), which could not be fully accounted for by correction procedures. Smaller relative changes in water content between two images can be derived by specific calibrations to two sample regions with different, invariant water contents.

  5. Static dissolution of UO2 in interstitial Boom Clay water

    International Nuclear Information System (INIS)

    Static dissolution experiments were performed with unirradiated UO2 in Boom Clay water. The objectives were (1) to measure the solubility of uranium species in Boom Clay water, with UO2 as the solid phase, and (2) to assess the impact of dissolved organic matter and carbonate concentration on this solubility. The tests were supported by calculations with geochemical codes to indicate possibly solubility controlling solid phases. The tests were performed in anoxic and reducing conditions, at 20 and 25 C. The following conclusions could be drawn: (1) Within 2 months in anoxic conditions, the uranium concentrations appear to approach saturation. (2) The near-saturation concentrations are between 2.4 and 7.8x10-7 M. (3) The influence of the carbonate concentration and humic acids on the uranium concentration was apparently small, but the interpretation is hampered by pH and Eh and/or pH conditions; this can probably be explained by small differences in experimental conditions. (5) The measured near steady-state uranium concentration in the real clay water agrees relatively well with the solubility calculated for uraninite. (6) Addition of sulfide species reduced the redox potential, but not the uranium concentrations, except in real Boom Clay water

  6. Boom clay pore water geochemistry at Mol site - State of the art

    International Nuclear Information System (INIS)

    of most elements at the base of the Putte Member reflects the presence of the 'double band', i.e. two coarser (silty) layers at this location. A coherent geochemical model was proposed by De Craen et al. (2004) to account for the pore water chemistry observed in the MORPHEUS piezometer (installed vertically downward from HADES URF). The model, assuming mineral dissolution/precipitation and cation exchange reactions as the principal processes, could reasonably well reproduce the observed data ranges. However, due to technical difficulties to measure reliably in situ pH and pCO2 at the time, these parameters were fitted by the model. In addition, the observed data ranges covered only a limited part of the Boom Clay and thus were not necessarily representative of the whole Boom Clay Formation. Recent progress in the optimisation of the sampling and measurement procedures led to the installation of a new circulation system around the PRACLAY gallery and an in-house routine application of gas analyses. In addition, a systematic screen for microbial activity became an integral part of the sampling campaigns in the piezometers around PRACLAY to verify the absence of microbial interference with the observed geochemical data. Today, we are able to probe in situ pH, pCO2 and pore water chemistry simultaneously. In this context, we can test, improve and further develop the present Boom Clay pore water geochemical model. Also, the use of additional piezometers for pore water sampling provides complementary data on larger scale thus better representing the overall natural variations in the Boom Clay pore water at Mol site. The modelling effort focuses on explaining the variations in the pore water chemistry observed in the Boom Clay at the formation scale. In-situ measured pH and pCO2 will serve as independent controllers to verify the robustness of the updated model. (authors)

  7. INTERACTIONS BETWEEN ORGANIC COMPOUNDS AND CYCLODEXTRIN-CLAY SYSTEMS

    Science.gov (United States)

    Computational and experimental techniques are combined in order to better understand interactions involving organic compounds and cyclodextrin (CD)-clay systems. CD-clay systems may have great potential in the containment of organic contaminants in the environment. This study w...

  8. Networking and rheology of concentrated clay suspensions "matured" in mineral medicinal water.

    Science.gov (United States)

    Aguzzi, Carola; Sánchez-Espejo, Rita; Cerezo, Pilar; Machado, José; Bonferoni, Cristina; Rossi, Silvia; Salcedo, Inmaculada; Viseras, César

    2013-09-10

    This work studied the influence of "maturation" conditions (time and agitation) on aggregation states, gel structure and rheological behaviour of a special kind of pharmaceutical semisolid products made of concentrated clay suspensions in mineral medicinal water. Maturation of the samples was carried out in distilled and sulphated mineral medicinal water, both in static conditions (without agitation) and with manual stirring once a week, during a maximum period of three months. At the measured pH interval (7.5-8.0), three-dimensional band-type networks resulting from face/face contacts were predominant in the laminar (disc-like) clay suspensions, whereas the fibrous (rod-like) particles formed micro-aggregates by van der Waals attractions. The high concentration of solids in the studied systems greatly determined their behaviour. Rod-like sepiolite particles tend to align the major axis in aggregates promoted by low shearing maturation, whereas aggregates of disc-like smectite particles did not have a preferential orientation and their complete swelling required long maturation time, being independent of stirring. Maturation of both kinds of suspensions resulted in improved rheological properties. Laminar clay suspensions became more structured with time, independently from static or dynamic maturation conditions, whereas for fibrous clay periodic agitation was also required. Rheological properties of the studied systems have been related to aggregation states and networking mechanisms, depending on the type of clay minerals constituents. Physical stability of the suspensions was not impaired by the specific composition of the Graena medicinal water.

  9. Water diffusion through compacted clays analyzed by neutron scattering and tracer experiments

    International Nuclear Information System (INIS)

    Clay minerals are aluminium phyllosilicates, mostly products of the chemical alteration and mechanical breakdown of igneous and metamorphic rocks. Their physical and chemical properties can be directly related to their layered, fine-grained (large surface area) structure. These properties such as large water retention, low hydraulic conductivity, heat resistance and ionic exchange capacities, make clays ideal for many different applications, e.g. as sealing material for the underground disposal of radioactive waste. The long-term disposal of radioactive waste in an underground geological repository is based on a multibarrier concept. In the barrier of highly compacted clay, water is intercalated and confined between the clay layers. The narrow pores are responsible that under natural hydraulic gradients, molecular diffusion through water is the dominant transport mechanism for released radionuclides. The properties of water at the water-clay interface differ from that of bulk water. Therefore, a good and deep understanding of the water structure and dynamics in compacted clay systems is fundamental. This knowledge is the base for the progressing research about transport of pollutants through the compacted clays and argillaceous rock of radioactive waste barriers. This study focusses on four different types of pure clays, two of them charged, namely montmorillonite and illite (both in a Na and Ca form), and two uncharged, namely kaolinite and pyrophyllite. Their structural differences result in a significantly different behaviour in contact with water. In case of montmorillonite, water is located in between particles and in the interlayer space. In illite, water is found only in between particles, because the interlayer surfaces are tightly linked by potassium cations. The layers of kaolinite and pyrophyllite are uncharged and, consequently, water is located only in between particles. The clay powders were compacted to reach a high bulk dry density of about 1.9 g

  10. Water diffusion through compacted clays analyzed by neutron scattering and tracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Sanchez, F

    2007-11-15

    Clay minerals are aluminium phyllosilicates, mostly products of the chemical alteration and mechanical breakdown of igneous and metamorphic rocks. Their physical and chemical properties can be directly related to their layered, fine-grained (large surface area) structure. These properties such as large water retention, low hydraulic conductivity, heat resistance and ionic exchange capacities, make clays ideal for many different applications, e.g. as sealing material for the underground disposal of radioactive waste. The long-term disposal of radioactive waste in an underground geological repository is based on a multibarrier concept. In the barrier of highly compacted clay, water is intercalated and confined between the clay layers. The narrow pores are responsible that under natural hydraulic gradients, molecular diffusion through water is the dominant transport mechanism for released radionuclides. The properties of water at the water-clay interface differ from that of bulk water. Therefore, a good and deep understanding of the water structure and dynamics in compacted clay systems is fundamental. This knowledge is the base for the progressing research about transport of pollutants through the compacted clays and argillaceous rock of radioactive waste barriers. This study focusses on four different types of pure clays, two of them charged, namely montmorillonite and illite (both in a Na and Ca form), and two uncharged, namely kaolinite and pyrophyllite. Their structural differences result in a significantly different behaviour in contact with water. In case of montmorillonite, water is located in between particles and in the interlayer space. In illite, water is found only in between particles, because the interlayer surfaces are tightly linked by potassium cations. The layers of kaolinite and pyrophyllite are uncharged and, consequently, water is located only in between particles. The clay powders were compacted to reach a high bulk dry density of about 1.9 g

  11. Modelling unfrozen water content in a silty clay permafrost deposit

    DEFF Research Database (Denmark)

    Agergaard, Frederik Ancker; Ingeman-Nielsen, Thomas

    2011-01-01

    of a calibration equation for determining the unfrozen water content of a Greenlandic silty clay permafrost deposit. Calibration experiments have been conducted for water contents in the interval 0 – 10 % at both 5 °C and 22 °C. Calibration equations are verified against permittivity data from a permafrost core......The mechanical properties of both unfrozen soils and permafrost soils are influenced by the amount of unfrozen water in the pore space. When dealing with foundation engineering in permafrost areas it is essential to estimate the unfrozen water content (wu). This paper deals with the establishing...... of material properties similar to the test soil. The calibration for 5°C is seen to make a good fit to the permafrost core data. Further experiments should be performed in order to extend the range of water contents tested and hence the range of validity of the calibration equation....

  12. Geology, Surficial - CLAY_ILITH_IN: Total Thickness of Clay in Indiana, Derived from the iLITH Water-Well Database (Indiana Geological Survey, Grid)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — CLAY_ILITH_IN is a grid that shows total thickness of clay, as derived from logs of water wells in the state of Indiana. (It presents the same data as shown in a...

  13. Geology, Surficial - CLAY_ILITH_PTS_IN: Total Thickness of Clay in Indiana, Derived from the iLITH Water-Well Database (Indiana Geological Survey, Point Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — CLAY_ILITH_PTS_IN is a point shapefile that shows total thickness of clay, as derived from logs of water wells in the state of Indiana. (It presents the source data...

  14. An Aquifer Reflections on Deep Clay Conditions for Water Quantity Assessments

    Directory of Open Access Journals (Sweden)

    Sabariah Musa

    2014-09-01

    Full Text Available This study aims to evaluate the on-site testing of deep clay area through the well response and aquifer reflection analysis. The analysis was conducted using AQTESOLV software on pumping and recovery data to determine the well responses and aquifer characteristics of deep clay area. A simple experimental model was installed at the site using deep well of REWES (Recharge Well System model assists with four monitoring wells around the model. The monitoring wells were located at 4m, 10m, 20m and 35m from the model. The site has been identified identified to have the unconfined aquifer with deep compacted clay. Due to flatten and low flow, pumping analysis and ground water response were used to evaluate water quantity and potential prospective of circulate water cycle for urban stormwater management. As reflection on water cycle, almost 20% from withdrawal capacity able to refill the ground system with limited space. It was found that the available storage, S and hydraulic conductivity, K  of the clayey area are 0.001 and 32 m/day respectively. Therefore, the response on water cycle indicate some potential space to restore and withdrawal at peak time and thus, the  water can be used in safely conditions.

  15. Fabric and clay activity in soil water retention behaviour

    Directory of Open Access Journals (Sweden)

    Jommi Cristina

    2016-01-01

    Full Text Available Modelling the water retention behaviour requires proper understanding of all the processes which affect the amount of water stored in the pore network, depending on the soil state and the soil history. Traditionally, in many applications a single water content – suction curve is used. This approach limits the applicability of the retention data to practical cases, especially when fine grain soils are dealt with, when the deformability and activity of the clay fraction significantly affect the interaction with water. On the other side, water retention is being recognised more and more as a fundamental information in the description of the mechanical response of the soil, as it provides the key connection to the partial volumetric strains in a deformation process. With reference to the work performed at the Politecnico di Milano in the last years, a contribution on the understanding and modelling the coupled water retention- mechanical response in deformable soils is presented. The contribution aims to: (i summarise the mechanisms which contribute to water retention; (ii point out the role played by an evolving fabric and the fluid properties on water retention; and (iii provide an overview on some of the consequences of evolving water retention properties on the mechanical behaviour.

  16. Determination of geochemical characters of insterstitial waters of pleistocene Italian clay formations

    International Nuclear Information System (INIS)

    The geochemical characters of clay formations and of their pore water are fundamental with regards to the mobility of the radionuclides as well as to the corrosion processes on enginered barriers. Experimental researches have been carried out in different types of clay, which represent Italian formations, for the characterization of pore water. A squeezer system, which reaches 1500 Kg/cm2 in pressure, and an analytical micro-scale methodology, for the determination of dissolved constituents in pore water, were set up. The extracted pore water ranges from 60% to 85% in relation to consolidation state of clay. The chemical composition of the extracted fluid has been checked during the squeezing. During this step the observed variations were smaller than those between the different specimens of the same sample. The comparison between the results obtained by squeezing and by a multiple washing technique, using increasing water/sediment ratios, shows that the last one does not give reliable results on the chemical composition of pore water. This is due to the presence of easily weatherable minerals and to the exchange processes between the clayey minerals and the solution. Nevertheless both these techniques have supplied complementary information about geochemical processes in water-rock interaction. The salinity of pore water ranges from 0.45 g/l to 24.5 g/l and the chemism always shows a high content of calcium-magnesium sulfate, or sodium chloride or calcium-magnesium-sulfate with sodium chloride. The correlation between geochemical composition of pore water and mineralogical composition of clay is not significant

  17. Probing Contaminant Transport to and from Clay Surfaces in Organic Solvents and Water Using Solution Calorimetry.

    Science.gov (United States)

    Pourmohammadbagher, Amin; Shaw, John M

    2015-09-15

    Clays, in tailings, are a significant ongoing environmental concern in the mining and oilsands production industries, and clay rehabilitation following contamination poses challenges episodically. Understanding the fundamentals of clay behavior can lead to better environmental impact mitigation strategies. Systematic calorimetric measurements are shown to provide a framework for parsing the synergistic and antagonistic impacts of trace (i.e., parts per million level) components on the surface compositions of clays. The enthalpy of solution of as-received and "contaminated" clays, in as-received and "contaminated" organic solvents and water, at 60 °C and atmospheric pressure, provides important illustrative examples. Clay contamination included pre-saturation of clays with water and organic liquids. Solvent contamination included the addition of trace water to organic solvents and trace organic liquids to water. Enthalpy of solution outcomes are interpreted using a quantitative mass and energy balance modeling framework that isolates terms for solvent and trace contaminant sorption/desorption and surface energy effects. Underlying surface energies are shown to dominate the energetics of the solvent-clay interaction, and organic liquids as solvents or as trace contaminants are shown to displace water from as-received clay surfaces. This approach can be readily extended to include pH, salts, or other effects and is expected to provide mechanistic and quantitative insights underlying the stability of clays in tailings ponds and the behaviors of clays in diverse industrial and natural environments. PMID:26296102

  18. Quantification of water content across a cement-clay interface using high resolution neutron radiography

    OpenAIRE

    Shafizadeh, A; Gimmi, Thomas; Van Loon, L.; Kaestner, A.; Lehmann, E; Mäder, Urs; Churakov, Sergey

    2015-01-01

    In many designs for radioactive waste repositories, cement and clay will come into direct contact. The geochemical contrast between cement and clay will lead to mass fluxes across the interface, which consequently results in alteration of structural and transport properties of both materials that may affect the performance of the multi-barrier system. We present an experimental approach to study cement-clay interactions with a cell to accommodate small samples of cement and clay. The cell des...

  19. Boom clay pore water, home of a diverse microbial community

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Boom Clay pore water (BCPW) has been studied in the framework of geological disposal of nuclear waste for over two decades, thereby mainly addressing its geochemical properties. A reference composition for synthetic clay water has been derived earlier by modelling and spatial calibration efforts, mainly based on interstitial water sampled from different layers within the Boom clay. However, since microbial activity is found in a range of extreme circumstances, the possibility of microbes interacting with future radioactive waste in a host formation like Boom Clay, cannot be ignored. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by a complementary set of microbiological and molecular techniques, in search for overall shared and abundant microorganisms. Similar to the previous characterization of the 'average' BCPW chemical composition, the primary aim of this microbiological study is to determine a representative BCPW microbial community which can be used in laboratory studies. Secondly, the in situ activity and the metabolic properties of members of this community were addressed, aiming to assess their survival and proliferation chances in repository conditions. In a first approach, total microbial DNA of the community was extracted from the BCPW samples. This molecular approach allows a broad insight in the total microbial ecology of the BCPW samples. By polymerase chain reaction (PCR) on the highly conserved 16S rRNA genes in this DNA pool and subsequent sequencing and bio-informatics analysis, operational taxonomic units (OTUs) could be assigned to the microbial community. The bacterial community was found to be quite diverse, with OTUs belonging to 8 different phyla (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chlorobi, Spirochetes, Chloroflexi and Deinococcus-Thermus). These results provide an overall view of the

  20. Procedure for preparation of high-water-content hydrogels using clay and a dendritic molecular binder

    OpenAIRE

    sprotocols

    2015-01-01

    This protocol describes a facile, quick and reproducible preparation of hydrogels. The protocol requires four components: water, clay nanosheets (Clay-NS), a dendritic macromolecule (Gn-binder; n = generation number) and sodium polyacrylate (ASAP). Upon mixing with ASAP in water, Clay-NS, which are heavily entangled with one another, are exfoliated and dispersed homogenously because of a possible site-specific wrapping of their positive-charged edge parts with anionic ASAP. Meanwhile, Gn-bind...

  1. Modeling and Simulation of Virtual Clay Pigeon shooter Training System

    Directory of Open Access Journals (Sweden)

    Jin Yanxia

    2013-10-01

    Full Text Available As a popular sports event, clay pigeon uses real guns and bullets as its tools. To improve the training effect, reduce its cost and danger, the development of a real-time interactive and perceptive virtual training system by using simulation technology becomes urgent. This system uses Visual C++、Vega、Creator as its development platform to conduct modeling and simulation of clay pigeon’s and grapeshot ‘s flying path and the collision effect of the two objects.  

  2. Electrical properties of water in clay and silty soils

    Science.gov (United States)

    Saarenketo, Timo

    1998-10-01

    In order to better understand ground penetrating radar (GPR) results obtained in road surveys and site investigations, the dielectric properties and electrical conductivity of four silt and clay soils were measured at different densities and moisture contents ranging from oven dry material to the plastic state. The real parts K' and imaginary parts K″ of the relative dielectric permittivity values of the soils were measured with an HP Surface Network Analyzer over a frequency range from 30 MHz to 3.0 GHz. A dielectric and electrical conductivity meter produced by Adek was also used. The results suggest that water in soils can be classified according to its electrical properties as: (1) an adsorption water layer, also known as the hygroscopic water layer; (2) a viscous or capillary water layer; and (3) free water. The measurements also showed that the adsorption water layer can be divided into inner and outer layers in accordance with the electrical double layer theory. The imaginary part of the dielectric value of the material is formed mainly in the outer layer and partly in the viscous (capillary) water layer, which also has two layers with differing electrical properties. The measurements also clearly showed that if the Cation Exchange Capacity (CEC) of a material is low, the water molecules are orderly arranged around the soil particles and the dielectric values of the bound water layers remain almost independent of frequency. If the CEC increases, the molecular structure of the bound water layers is disturbed and the water molecules more easily follow the changing AC field so that the dielectric value is higher. These materials are also highly dielectrically dispersive, especially at GPR frequencies below 400 MHz. Increasing CEC correlates well with increasing imaginary part of the adsorption water layer. Measured ohmic electrical conductivities were low at low moisture content and increased as the outer viscous water layer developed with higher moisture

  3. Preferential flow paths in a water repellent clay soil with grass cover

    NARCIS (Netherlands)

    Dekker, L.W.; Ritsema, C.J.

    1996-01-01

    Grass-covered heavy basin clay soils in the Netherlands appeared to be water-repellent. Water-repellency in the top layers of these soils occurred mainly as a coating on the aggregates. Differences between minimum and maximum soil moisture contents were high in all the layers sampled. When the clay

  4. Clay-biodegradable polymer combination for pollutant removal from water

    OpenAIRE

    M. F. Mohd Amin; S. G. J. Heijman; L. C. Rietveld

    2015-01-01

    In this study, a new treatment alternative is investigated to remove micropollutants from wastewater effectively and in a more cost-effective way. A potential solution is the use of clay in combination with biodegradable polymeric flocculants. Flocculation is viewed as the best method to get the optimum outcome from the combination of clay with starch. Clay is naturally abundantly available and relatively inexpensive compared to the conven...

  5. Improving the Hydraulic Performance of Stormwater Infiltration Systems in Clay Tills

    DEFF Research Database (Denmark)

    Bockhorn, Britta

    investigations on two typical Danish clay till sites, and one modeling study with the integrated surface water and groundwater model HydroGeoSphere. The saturated hydraulic conductivity (Ksat) is the most critical soil physical parameter when it comes to sizing stormwater infiltration systems. In the first study...... in clay tills has potential for improving the hydraulic performance of stormwater infiltration systems. The third study was an assessment of the influence of small-scale soil physical features in clay tills on the hydraulic performance of stormwater infiltration systems based on a HydroGeoSphere model......% if biopores like earthworm burrows were also added. A comparison of HydroGeoSphere infiltration hydrographs with a simple soakaway model (Roldin et al. 2012b) showed that the exclusion of small-scale soil physical features may result in significant underestimation of the hydraulic performance of stormwater...

  6. Impact factors on the structuration and the rheological behavior of the clay-water system for smectite dispersions; Facteurs determinant l'organisation et la rheologie du systeme argile-eau pour des suspensions de smectites

    Energy Technology Data Exchange (ETDEWEB)

    Paumier, S

    2007-11-15

    Smectite are swelling clays widely used in industry. Their mechanical properties are unequal according to their mineralogical and physico-chemical characteristics. The aim of this study is to improve the knowledge of the interlayer cation impact on the structure built by the smectite-water system according to the concentration. Homo-ionic (Na{sup +} et Ca{sup 2+}) and bi-ionic systems are observed. This study cross checks mineralogical methods, physicochemical analysis and broad range of rheometric tests. At low concentration (less than 60 g/l) the calcium dispersions are shear thinning and few viscous due to the layer association in huge deformable flocks. The sodium smectite layers are dispersed; the dispersions are highly viscous. The lowest viscosity is detected for mix of 20 % of sodium smectite and 80 % of calcium smectite. At higher concentration (60 to 100 g/l), the yield stress and viscoelastic properties are studied by creep-recovery tests, oscillatory tests and imposed shear step. At the liquid state, the flow is first heterogeneous with a shear banding effect then homogeneous. The results make it possible to define the concentration area characteristic of each mechanical behavior (viscosity, shear thinning and yield stress) according to the saturation cation. The thixotropic properties are characterized with de-structuring-restructuring tests. Two kinetics are determined. Finally we realize a data base with 12 natural and industrial bentonite. The rheograms would be efficient to differentiate the natural calcium bentonite (Newtonian law), natural sodium bentonite (Herschel-Bulkley law) and activated calcium bentonite (Bingham law). (author)

  7. Brazilian clay organophilization aiming its use in oil / water removal

    International Nuclear Information System (INIS)

    Clays when subjected to modification with the addition of organic surfactant are called organoclays acquire hydrophobic character, they have an affinity for organic compounds. The organoclays can be used as adsorbents are considered promising agents in environmental control. The objective is to prepare organoclays clays from commercial use in order to remove organic contaminants. The clay used was gray, as polycationic, supplied by Süd-Chemie company and the quaternary ammonium salt was cetyltrimethylammonium bromide (Cetremide). The fresh samples and organoclay were characterized by the technique of X-ray diffraction (XRD), Cation Exchange Capacity, testing expansion and affinity with organic compounds: Swelling of Foster and adsorption capacity. The results showed appropriate conditions organophilic process. Through XRD confirmed the increase in basal spacing for the modified clay in relation to the clay in nature. (author)

  8. Effect of Ionic Soil Stabilizers on Soil-Water Characteristic of Special Clay

    Science.gov (United States)

    Cui, D.; Xiang, W.

    2011-12-01

    The engineering properties of special clay are conventionally improved through the use of chemical additive such as ionic soil stabilizer (ISS). Such special clays are often referred to as stabilized or treated clays. The soil-water characteristic curves (SWCC) of special clays from Henan province and Hubei province were measured both in natural and stabilized conditions using the pressure plate apparatus in the suction range of 0-500 kPa. The SWCC results are used to interpret the special clays behavior due to stabilizer treatment. In addition, relationships were developed between the basic clay and stabilized properties such as specific surface area and pore size distribution. The analysis showed that specific surface area decreases, cumulative pore volume and average pore size diameter decrease, dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. The research data and interpretation analysis presented here can be extended to understand the water film change behaviors influencing the mechanical and physical properties of stabilized special clay soils. KEY WORDS: ionic soil stabilizer, special clay, pore size diameter, specific surface area, soil water characteristic curve, water film

  9. Influence of ionic strength on the transport parameters of tritiated water and iodide in boom clay

    International Nuclear Information System (INIS)

    To fulfil its role as main barrier for High and Medium Level radioactive waste (HLW and MLW), Boom Clay relies on its advantageous capacity to minimise radionuclide transport by its slow diffusion and high retention properties. One of the key parameters in the radionuclide dispersion process is the diffusion accessible porosity (ηacc). Diffusion accessible porosity, is a transport parameter that is linked to the properties of each dispersing radionuclide and the geochemical conditions of Boom Clay. Disposing radioactive waste in Boom Clay will inevitably cause perturbations of which some can generate changes in the Boom Clay pore water chemistry. One effect of these chemical perturbations will be the increase of ionic strength of the pore water in the vicinity of a repository. This paper synthesises the results of the experimental work done to obtain the transport parameters of tritiated water and iodide for Boom Clay at different ionic strengths. (authors)

  10. Evaluation of natural clay Brasgel as adsorbent in removal of lead in synthetic waste water

    International Nuclear Information System (INIS)

    The smectite clays have high adsorption capacity and cation exchange. Due to its chemical and physical characteristics, they can be effectively used as adsorbent of pollutants (such as metal ions). The initial objective of this study was to characterize the clay Brasgel through the techniques of X-Ray Diffraction (XRD), X-Ray Spectrometry by Energy Dispersive (EDX) and nitrogen adsorption (BET method), seeking its use in removing lead (Pb2+) from synthetic effluents. System was used in finite bath to assess the potential removal of lead (Pb2+), following a 22 factorial experimental design with three center point experiments, taking as input variables: pH and initial concentrations of lead (Pb2+). The clay has Brasgel clay in its composition that characterize it as a smectite clay. By having a large surface area, this clay showed great potential on the adsorption of metal ions. (author)

  11. Diffusion and electromigration in clay bricks influenced by differences in the pore system resulting from firing

    DEFF Research Database (Denmark)

    Rörig-Dalgaard, Inge; Ottosen, Lisbeth M.; Hansen, Kurt Kielsgaard

    2012-01-01

    Ion transport in porous materials has been subject of study for several decades. However, the interaction between the pores and the overall pore system make it complicated to obtain a clear picture and predict diffusion and electromigration (transport induced by an applied electric field). Specific...... the pore system to contribute to an overall understanding of ion transport in porous materials.The pore system in bricks are influenced by the firing degree, clay mixture composition and ion content. The present paper focuses on the pore system and effects from clay mixture composition and ion content were...... to the distance to the surface.The influence of the pore system on ion transport through the water saturated pore system of the bricks was supported by measurements for calculation of the electrical resistance and an increasing resistance was found for increasing brick firing temperatures. The effective diffusion...

  12. Multi scale experimental study of water and ionic transport in porous charged media: clays

    International Nuclear Information System (INIS)

    Clays are porous media of industrial interest. Due to their retention capacities and low permeability to water, they are the principal candidate for the conception of engineered barriers radioactive waste disposal. The main interest of this study is the experimental determination of the cationic and water dynamics in montmorillonite and fluoro-hectorite at low water contents This latter synthetic smectite has been used as a model clay to help the interpretation of the results issued from the first natural one. After a summary on the clayey system, this work reports the many experimental techniques (Atomic Force Microscopy, Photo-Correlation Spectroscopy, Micro-calorimetry, Powder Diffraction) used during the preliminary study concerning structural characterisation of the samples. The study of the sodic form of smectites with the use of a combination of quasi-elastic neutron scattering techniques (Time of Flight and Spin Echo) succeeded to water diffusion coefficients but also to a discernment of the limits of such techniques. Experiments with montmorillonite samples are in agreement with the simulations, so tending to a validation of the models. Experimental data obtained from synthetic hectorites will be in the near future compared to simulations In the last part, this work shows the application of Broad Band Dielectric Spectroscopy for the investigation of ionic dynamic in these porous media. Many models have been developed for the interpretation of the experimental raw data obtained with this technique. (author)

  13. Soil-Water Characteristic Curves of Red Clay treated by Ionic Soil Stabilizer

    Science.gov (United States)

    Cui, D.; Xiang, W.

    2009-12-01

    The relationship of red clay particle with water is an important factor to produce geological disaster and environmental damage. In order to reduce the role of adsorbed water of red clay in WuHan, Ionic Soil Stabilizer (ISS) was used to treat the red clay. Soil Moisture Equipment made in U.S.A was used to measure soil-water characteristic curve of red clay both in natural and stabilized conditions in the suction range of 0-500kPa. The SWCC results were used to interpret the red clay behavior due to stabilizer treatment. In addition, relationship were compared between the basic soil and stabilizer properties such as water content, dry density, liquid limit, plastic limit, moisture absorption rate and stabilizer dosages. The analysis showed that the particle density and specific surface area increase, the dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. After treatment with the ISS, the geological disasters caused by the adsorbed water of red clay can be effectively inhibited.

  14. Advances in Application of Natural Clay and Its Composites in Removal of Biological, Organic, and Inorganic Contaminants from Drinking Water

    OpenAIRE

    Rajani Srinivasan

    2011-01-01

    Natural clays are abundantly available low-cost natural resource which is nontoxic to ecosystem. Over the recent years, research on the modification of clay to increase their adsorbent capacity to remove other contaminants from drinking water other than metals is in progress. This paper reviews the recent development of natural clays and their modified forms as adsorbing agents for treating drinking water and their sources. This paper describes the versatile nature of natural clay and their a...

  15. Stirring the Waters: The Influence of Marie Clay.

    Science.gov (United States)

    Gaffney, Janet S., Ed.; Askew, Billie J., Ed.

    Celebrating Marie Clay as a major theorist of child literacy acquisition, this book presents 15 essays by distinguished scholars that reflect on her contributions to the field of early literacy; early childhood, bilingual, and special education; developmental, cognitive, and school psychology; assessment; teacher education; professional…

  16. Coupled modelling (transport-reaction) of the fluid-clay interactions and their feed back on the physical properties of the bentonite engineered clay barrier system

    International Nuclear Information System (INIS)

    The originality of this work is to process feed back effects of mineralogical and chemical modifications of clays, in storage conditions, on their physical properties and therefore on their transport characteristics (porosity, molecular diffusion, permeability). These feed back effects are modelled using the KIRMAT code (Kinetic of Reaction and MAss Transfer) developed from the kinetic code KINDIS by adding the effect of water renewal in the mineral-solution reactive cells. KIRMAT resolves mass balance equations associated with mass transport together with the geochemical reactions in a 1D approach. After 100 000 years of simulated interaction at 100 C, with the fluid of the Callovo-Oxfordian geological level (COX) and with iron provided by the steel overpack corrosion, the montmorillonite of the clay barrier is only partially transformed (into illite, chlorite, saponite...). Only outer parts of the modelled profile seem to be significantly affected by smectite dissolution processes, mainly at the interface with the geological environment. The modifications of physical properties show a closure of the porosity at the boundaries of the barrier, by creating a decrease of mass transport by molecular diffusion, essentially at the interface with the iron. Permeability laws applied to this system show a decrease of the hydraulic conductivity correlated with the porosity evolution. Near the COX, the swelling pressure of the clays from the barrier decreases. In the major part of the modelled profile, the engineered clay barrier system seems to keep its initial physical properties (porosity, molecular diffusion, permeability, swelling pressure) and functionalities. (author)

  17. Integrated modelling of the glass-iron-clay system

    Energy Technology Data Exchange (ETDEWEB)

    Bildstein, O

    2007-01-15

    This report summarizes the results of integrated calculations on the near-field evolution in the VHLW/steel/bentonite/clay system. The calculations of the near-field evolution include different components: the vitrified waste packages, the steel container, the bentonite-based EBS (optional), the EDZ and the geological medium. Coupled reaction-transport (X-T) is used to simulate the corrosion of the steel canister and the glass alteration phase in presence of corrosion products (CPs), looking at mass transfer for chemical elements, especially iron and silica, pH, and porosity change. Calculations as performed give actual parameters for PA calculations: rate of glass alteration (through the calculated pH) as a function of time, extension of altered zone for iron-clay interactions with their own transport parameters, nature of CPs, effect on porosity distribution. According to the operational model currently used at the CEA and the calculations performed on the glass-iron-clay system, the alteration rate of glass and the evolution of the system strongly depend on the timing of CPs saturation with respect to silica sorption. The fate of silica which can be sorbed or precipitate is crucial to the lifetime of glass and to the overall evolution of the system. The other process that might influence the glass is the porosity decrease due to the precipitation of CPs and silica rich phases. However, it is difficult to assign a safety functions to clogging. It is scarcely observed in experiments, either because the conditions are not met for clogging or because the timescale of experiments does not allow for observable clogging. Moreover, the effect of mechanical stress in the NF has to be accounted for in the assessment of the effect of porosity changes. (author)

  18. Evaluation of Water Vapor Sorption Hysteresis in Soils: The Role of Organic Matter and Clay

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per;

    2015-01-01

    Hysteresis of the soil water characteristic (SWC) has been extensively studied for matric potentials between zero and −1.5 MPa. However, little information is available on how to quantify, evaluate, and identify the causes of hysteresis at potentials below −10 MPa where vapor sorption plays...... an important role. It is clear that modeling physical and biological soil processes is more accurate when SWC hysteresis is considered, particularly at low potentials where small differences in water content are associated with large changes in potential energy. The objectives of the presented study were to......: (i) evaluate and compare recently developed methods (MBET-n, Dh and SPN) for quantifying hysteresis in soils and pure clays, and (ii) investigate the role of organic matter (OM) and clay content and type on hysteresis. Five pure clays and two sets of soils with gradients in organic matter and clay...

  19. Pore characteristics and their emergent effect on water adsorption and transport in clays using small-angle neutron scattering with contrast variation

    Science.gov (United States)

    Ding, M.; Hartl, M.; Wang, Y.; Hjelm, R.

    2013-12-01

    In nuclear waste management, clays are canonical materials in the construction of engineered barriers. They are also naturally occurring reactive minerals which play an important role in retention and colloidal facilitated reactive transport in subsurface systems. Knowledge of total and accessible porosity in clays is crucial in determining fluids transport behavior in clays. It will provide fundamental insight on the performance efficiency of specific clays as a barrier material and their role in regulating radionuclide transport in subsurface environments. The aim of the present work is to experimentally investigate the change in pore characteristics of clays as function of moisture content, and to determine their pore character in relation to their water retention capacity. Recent developments in small-angle neutron scattering (SANS) techniques allow quantitative measurement of pore morphology and size distribution of various materials in their pristine state under various sample environments (exposure to solution, high temperature, and so on). Furthermore, due to dramatic different neutron scattering properties of hydrogen and deuterium, one can readily use contrast variation, which is the isotopic labeling with various ratios of H and D (e.g. mixture of H2O/D2O) to highlight or suppress features of the sample. This is particularly useful in the study of complex pore system such as clays. In this study, we have characterized the pore structures for a number of clays including clay minerals and field samples which are relevant to high-level waste systems under various sample environments (e.g., humidity, temperature and pressure) using SANS. Our results suggest that different clays show unique pore features under various sample environments. To distinguish between accessible/non-accessible pores and the nature of pore filling (e.g. the quantity of H2O adsorbed by clays, and the distribution of H2O in relation to pore character) to water, clays were exposed for

  20. A large-scale laboratory investigation into the movement of gas and water through clay barriers exposed to the environment

    International Nuclear Information System (INIS)

    This report describes a large scale laboratory investigation into the movements of gas and water through clay barriers exposed to the environment. The test beds, each 3m square were constructed and filled with clay to a depth of 400 mm, after compaction. One test bed contained London Clay, the other Glacial Till. The clays were subjected to accelerated environmental cycling and tests carried out on samples of the clays at appropriate intervals. The tests included measurements of the mechanical, physical and chemical properties of the clays and their permeability to gas and water. Gas permeability emerged as the more appropriate for the clays being investigated. The report discusses the difficulties of measuring the permeability of partially saturated clays and the need to define the measuring techniques when specifying limiting acceptability values. 55 refs., 8 figs., 7 tabs., 27 plates

  1. Bioremediating Oil Spills in Nutrient Poor Ocean Waters Using Fertilized Clay Mineral Flakes: Some Experimental Constraints

    OpenAIRE

    Warr, Laurence N.; André Friese; Florian Schwarz; Frieder Schauer; Portier, Ralph J.; Basirico, Laura M.; Gregory M. Olson

    2013-01-01

    Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contai...

  2. Bioremediating Oil Spills in Nutrient Poor Ocean Waters Using Fertilized Clay Mineral Flakes: Some Experimental Constraints

    Directory of Open Access Journals (Sweden)

    Laurence N. Warr

    2013-01-01

    Full Text Available Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98% of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity.

  3. Bioremediating oil spills in nutrient poor ocean waters using fertilized clay mineral flakes: some experimental constraints.

    Science.gov (United States)

    Warr, Laurence N; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J; Basirico, Laura M; Olson, Gregory M

    2013-01-01

    Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98%) of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity. PMID:23864952

  4. Simulation of Water-Resistance of a Clay Layer During Mining: Analysis of a Safe Water Head

    Institute of Scientific and Technical Information of China (English)

    DONG Qing-hong; CAI Rong; YANG Wei-feng

    2007-01-01

    Given previous research and prototypical geological conditions of a mining workface, we simulated fissure development in clay layers at the bottom of Quaternary strata and above bedrock, sand and water inrush during mining by model experiments. The results show that V-shaped fissures usually occur in the bottom clay layer at the front top of the active face and that the position of these fissures changes periodically with ground pressure intervals. These fissures occur exactly in the area where the horizontal strain is concentrated. The results also demonstrate that the permeability coefficient of the cracked clay decreases while fissures tend to close. The permeability of the cracked bottom clay layer increases rapidly after a turning point in the permeability coefficient-water head curve (K-H curve) under a certain vertical load. Under static water pressure, the permeability coefficient of cracked clay decreases when load increases. A turning point in the K-H curve showed up and can be seen as a cutoff point to decide water inrush under a certain load level. Under an instantaneous water head, the greatest ability of the cracked clay to avoid drastic water inflow is a little higher than that under static conditions.

  5. Investigating the pore-water chemistry effects on the volume change behaviour of Boom clay

    International Nuclear Information System (INIS)

    The Essen site has been chosen as an alternative site for nuclear waste disposal in Belgium. The soil formation involved at this site is the same as at Mol site: Boom clay. However, owing to its geographical situation closer to the sea, Boom clay at Essen presents a pore water salinity 4-5 times higher than Boom clay at Mol. This study aims at studying the effects of pore water salinity on the hydro-mechanical behaviour of Boom clay. Specific odometer cells were used allowing 'flushing' the pore water in soil specimen by synthetic pore water or distilled water. The synthetic pore water used was prepared with the chemistry as that for the site water: 5.037 g/L for core Ess83 and 5.578 g/L for core Ess96. Mechanical loading was then carried out on the soil specimen after flushing. The results show that water salinity effect on the liquid limit is negligible. The saturation or pore water replacement under the in situ effective stress of 2.4 MPa does not induce significant volume change. For Ess83, hydro-mechanical behaviour was found to be slightly influenced by the water salinity; on the contrary, no obvious effect was identified on the hydro-mechanical behaviour of Ess96. This can be attributed to the higher smectite content in Ess83 than in Ess96. (authors)

  6. Water uptake of clay and desert dust aerosol particles at sub- and supersaturated water vapor conditions.

    Science.gov (United States)

    Herich, Hanna; Tritscher, Torsten; Wiacek, Aldona; Gysel, Martin; Weingartner, Ernest; Lohmann, Ulrike; Baltensperger, Urs; Cziczo, Daniel J

    2009-09-28

    Airborne mineral dust particles serve as cloud condensation nuclei (CCN), thereby influencing the formation and properties of warm clouds. It is therefore of atmospheric interest how dust aerosols with different mineralogy behave when exposed to high relative humidity (RH) or supersaturation (SS) with respect to liquid water. In this study the subsaturated hygroscopic growth and the supersaturated cloud condensation nucleus activity of pure clays and real desert dust aerosols were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA) and a cloud condensation nuclei counter (CCNC), respectively. Five different illite, montmorillonite and kaolinite clay samples as well as three desert dust samples (Saharan dust (SD), Chinese dust (CD) and Arizona test dust (ATD)) were investigated. Aerosols were generated both with a wet and a dry disperser. The water uptake was parameterized via the hygroscopicity parameter kappa. The hygroscopicity of dry generated dust aerosols was found to be negligible when compared to processed atmospheric aerosols, with CCNC derived kappa values between 0.00 and 0.02 (the latter corresponds to a particle consisting of 96.7% by volume insoluble material and approximately 3.3% ammonium sulfate). Pure clay aerosols were generally found to be less hygroscopic than natural desert dust particles. The illite and montmorillonite samples had kappa approximately 0.003. The kaolinite samples were less hygroscopic and had kappa=0.001. SD (kappa=0.023) was found to be the most hygroscopic dry-generated desert dust followed by CD (kappa=0.007) and ATD (kappa=0.003). Wet-generated dust showed an increased water uptake when compared to dry-generated samples. This is considered to be an artifact introduced by redistribution of soluble material between the particles. Thus, the generation method is critically important when presenting such data. These results indicate any atmospheric processing of a fresh mineral dust particle which

  7. Influence of Water Content on the Mechanical Behaviour of Limestone: Role of the Clay Minerals Content

    Science.gov (United States)

    Cherblanc, F.; Berthonneau, J.; Bromblet, P.; Huon, V.

    2016-06-01

    The mechanical characteristics of various sedimentary stones significantly depend on the water content, where 70 % loss of their mechanical strengths can be observed when saturated by water. Furthermore, the clay fraction has been shown to be a key factor of their hydro-mechanical behaviour since it governs for instance the hydric dilation. This work aims at investigating the correlations between the clay mineral content and the mechanical weakening experienced by limestones when interacting with water. The experimental characterization focuses on five different limestones that exhibit very different micro-structures. For each of them, we present the determination of clay mineral composition, the sorption isotherm curve and the dependences of tensile and compressive strengths on the water content. It emerges from these results that, first, the sorption behaviour is mainly governed by the amount of smectite layers which exhibit the larger specific area and, second, the rate of mechanical strength loss depends linearly on the sorption capacity. Indeed, the clay fraction plays the role of a retardation factor that delays the appearance of capillary bridges as well as the mechanical weakening of stones. However, no correlation was evidenced between the clay content and the amplitude of weakening. Since the mechanisms whereby the strength decreases with water content are not clearly established, these results would help to discriminate between various hypothesis proposed in the literature.

  8. Alteration, adsorption and nucleation processes on clay-water interfaces: Mechanisms for the retention of uranium by altered clay surfaces on the nanometer scale

    Science.gov (United States)

    Schindler, Michael; Legrand, Christine A.; Hochella, Michael F.

    2015-03-01

    Nano-scale processes on the solid-water interface of clay minerals control the mobility of metals in the environment. These processes can occur in confined pore spaces of clay buffers and barriers as well as in contaminated sediments and involve a combination of alteration, adsorption and nucleation processes of multiple species and phases. This study characterizes nano-scale processes on the interface between clay minerals and uranyl-bearing solution near neutral pH. Samples of clay minerals with a contact pH of ∼6.7 are collected from a U mill and mine tailings at Key Lake, Saskatchewan, Canada. The tailings material contains Cu-, As-, Co-, Mo-, Ni-, Se-bearing polymetallic phases and has been deposited with a surplus of Ca(OH)2 and Na2CO3 slaked lime. Small volumes of mill-process solutions containing sulfuric acid and U are occasionally discharged onto the surface of the tailings and are neutralized after discharge by reactions with the slaked lime. Transmission electron microscopy (TEM) in combination with the focused ion beam (FIB) technique and other analytical methods (SEM, XRD, XRF and ICP-OES) are used to characterize the chemical and mineralogical composition of phases within confined pore spaces of the clay minerals montmorillonite and kaolinite and in the surrounding tailings material. Alteration zones around the clay minerals are characterized by different generations of secondary silicates containing variable proportions of adsorbed uranyl- and arsenate-species and by the intergrowth of the silicates with the uranyl-minerals cuprosklodowskite, Cu[(UO2)2(SiO3OH)2](H2O)6 and metazeunerite, Cu[(UO2)(AsO4)2](H2O)8. The majority of alteration phases such as illite, illite-smectite, kaolinite and vermiculite have been most likely formed in the sedimentary basin of the U-ore deposit and contain low amounts of Fe (10 at.%) formed most likely in the limed tailings at high contact pH (∼10.5) and their structure is characterized by a low degree of long

  9. Modified Liu-Carter Compression Model for Natural Clays with Various Initial Water Contents

    Directory of Open Access Journals (Sweden)

    Sen Qian

    2016-01-01

    Full Text Available The initial water content has a significant effect on the compression behaviour of reconstituted clays. This effect has to be considered in the Liu-Carter model to ensure the addition voids ratio only related to soil structure. A modified Liu-Carter compression model is proposed by introducing the empirical equations for reconstituted clays at different initial water contents into the Liu-Carter model. The proposed model is verified against the experimental results from the literature. The simulations by the proposed method are also compared with that by old method where the influence of initial water content is not considered. The results show that the predicted virgin compression curves of natural clays are similar, but the values of b and Δey may be very different.

  10. Advances in Application of Natural Clay and Its Composites in Removal of Biological, Organic, and Inorganic Contaminants from Drinking Water

    Directory of Open Access Journals (Sweden)

    Rajani Srinivasan

    2011-01-01

    Full Text Available Natural clays are abundantly available low-cost natural resource which is nontoxic to ecosystem. Over the recent years, research on the modification of clay to increase their adsorbent capacity to remove other contaminants from drinking water other than metals is in progress. This paper reviews the recent development of natural clays and their modified forms as adsorbing agents for treating drinking water and their sources. This paper describes the versatile nature of natural clay and their ability to adsorb variety of contaminants ranging from inorganic to emerging, which are present in the drinking water. The properties and modification of the natural clay and its significance in removing a specific type of contaminant are described. The adsorbing efficiency of the natural and modified clay in the purification of drinking water, when compared to existing technologies, materials, and methods was found to be significantly higher or comparable.

  11. Water movement and isoproturon behaviour in a drained heavy clay soil: 1. Preferential flow processes

    Science.gov (United States)

    Haria, A. H.; Johnson, A. C.; Bell, J. P.; Batchelor, C. H.

    1994-12-01

    The processes and mechanisms that control pesticide transport from drained heavy clay catchments are being studied at Wytham Farm (Oxford University) in southern England. In the first field season field-drain water contained high concentrations of pesticide. Soil studies demonstrated that the main mechanism for pesticide translocation was by preferential flow processes, both over the soil surface and through the soil profile via a macropore system that effectively by-passed the soil matrix. This macropore system included worm holes, shrinkage cracks and cracks resulting from ploughing. Rainfall events in early winter rapidly created a layer of saturation in the A horizon perched above a B horizon of very low hydraulic conductivity. Drain flow was initiated when the saturated layer in the A horizon extended into the upper 0.06m of the soil profile; thereafter water moved down slope via horizontal macropores possibly through a band of incorporated straw residues. These horizontal pathways for water movement connected with the fracture system of the mole drains, thus feeding the drains. Overland flow occurred infrequently during the season.

  12. Effects of clay amendment on adsorption and desorption of copper in water repellent soils

    NARCIS (Netherlands)

    Xiong, X.; Stagnitti, F.; Allinson, G.; Turoczy, N.; Li, P.; LeBlanc, M.; Cann, M.A.; Doerr, S.H.; Steenhuis, M.M.; Parlange, J.Y.; Rooij, de G.; Ritsema, C.J.; Dekker, L.W.

    2005-01-01

    Copper is an important micronutrient and trace amounts are essential for crop growth. However, high concentrations of copper will produce toxic effects. Australia is increasingly developing production of crops in water repellent soils. Clay amendment, a common amelioration techniques used in Austral

  13. The interaction between Synroc-C and pure water or Boom clay

    International Nuclear Information System (INIS)

    The authors investigated the interaction between Synroc-C and deionized water or Boom clay disposal media. The authors used powdered Synroc-C to achieve high SA/V (surface area to volume) conditions (100, 1,000, 10,000 m-1). The temperature was 90 C. Reaction progress up to 10-+6 days/m was reached. They conclude that dissolution in DW is mainly controlled by initial ion exchange, followed by matrix dissolution. In both Boom clay media (a 500 g/l and a 2,000 g/l clay/claywater mixture) matrix dissolution is dominating. The depletion depth of the main Synroc constituent Ti is below 250 mn in the clay media, and below 2 nm in DW after 110 days corrosion at 100 m-1. The corrosion rates are very small, though the authors cannot present meaningful values. The effect of Boom clay is mainly to increase the solubility of Ti, Zr and the rare earths in solution

  14. Geomechanical and water vapor absorption characteristics of clay-bearing soft rocks at great depth

    Institute of Scientific and Technical Information of China (English)

    Zhang Na; Liu Longbiao; Hou Dongwen; He Manchao; Liu Yilei

    2014-01-01

    The geological and physico-mechanical properties characterization of deep soft rocks is one of the critical scientific issues for deep soft rock engineering. In the present study, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and mercury intrusion porosimetry experiments were carried out to investigate the mineral compositions, microstructure and porosity characteristics of the 13 clay-bearing soft rock samples collected from a deep coal mine in China. Water vapor absorption and uniaxial compressive experiments were also performed to examine water absorption characteristics and water-induced strength degradation effect of the investigated deep soft rock samples. The results show that the dominant mineral components in mudstone, coarse sandstone and fine sandstone samples were calcite, quartz and clay respectively. The contents of clay minerals in all samples were relatively high and ranged from 12.3% (N-4) to 56.5% (XS-1). Water vapor absorption processes of all the soft rock samples follow an exponential law which is very similar to the water vapor absorption behavior of conglomerate samples reported in our earlier study. Correlation analyses also suggested that there were good positive correlation relationships between water absorptivity and clay minerals for both mudstone and sandstone samples. Furthermore, it was found that vapor absorption was not correlated with the porosity for mudstone, however, positive correlation relationship was found between them for sand-stone. Correlation analysis between UCS, modulus of elasticity and water content demonstrated that both of them tend to decrease with the increase of their water content due to water absorption.

  15. Multi-scale modeling of the behaviour of water and ions clays

    International Nuclear Information System (INIS)

    Predicting the fate of radioactive waste stored in a clay formation requires a good understanding of the transport properties of water and ions in clays. Their diffusion in this charged porous medium is described by empirical parameters such as their partitioning coefficient Kd which accounts for the interactions with the mineral surfaces. The present work deals with the relevance of this concept and its definition based on microscopic grounds. We have first modeled the ionic contribution to the dielectric properties of clays and suggested an experimental determination of Kd from dielectric spectroscopy measurements. Using microscopic simulations (Monte-Carlo and Molecular Dynamics), we then have computed the Gibbs free energy and enthalpy for ionic exchange in the case of alkaline cations. They control the value of Kd and its evolution with the temperature. The results for cesium are in good agreement with both microcalorimetric measurements and the determination of Kd at different temperatures. We have participated in the development of a new lattice simulation method (Lattice Fokker-Planck), which we have then used to link explicitly the microscopic dynamics of ions to the diffusion-reaction model underlying the definition of Kd. Finally, we have used Molecular Dynamics to investigate the kinetics of exchange of water and ions between clay particles (interlayer) and the extra-particle porosity. The results confirm the generally admitted idea that water and ions can explore the whole porosity, whereas anions are excluded from the interlayers. (author)

  16. Water systems

    International Nuclear Information System (INIS)

    The present paper describes the coolant chemistry and its consequences for 1300 MWsub(e) KWU PWR plants. Some selected systems, i.e. primary heat transport system, steam water cycle and cooling water arrangements, are chosen for this description. Various aspects of coolant chemistry regarding general corrosion, selective types of corrosion and deposits on heat transfer surfaces have been discussed. The water supply systems necessary to fulfill the requirements of the coolant chemistry are discussed as well. It has been concluded that a good operating performance can only be achieved when - beside other factors - the water chemistry has been given sufficient consideration. (orig./RW)

  17. Water systems

    International Nuclear Information System (INIS)

    The present paper describes the coolant chemistry and its consequences for 1300 MWsub(e) KWU PWR plants. Some selected systems, i.e. primary heat transport system, steam water cycle and cooling water arrangements, are chosen for this description. Various aspects of coolant chemistry regarding general corrosion, selective types of corrosion and deposits on heat transfer surface have been discussed. The water supply systems necessary to fulfill the requirements of the coolant chemistry are discussed as well. It has been concluded that a good operating performance can only be achieved when - beside other factors - the water chemistry has been given sufficient consideration. (orig./RW)

  18. Radionuclide transport in the Neogene aquifer system located in the environment of the Boom clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the framework the Belgian research program on the long term management of high-level and/or long-lived radioactive waste coordinated by ONDRAF/NIRAS, the Boom Clay is considered as a reference host rock for the geological disposal of high-level radioactive waste in NE-Belgium (Campine area). In the frame of the performance assessments of a disposal system located in the Boom Clay Formation, the transport of radionuclides diffusing through the clay barrier into the aquifers located above is modelled. The transport model for the Neogene aquifer is based on a series of groundwater flow models simulating the aquifer systems in the surroundings of the Boom Clay. This series of groundwater models include the regional north-eastern Belgium model simulating flow both above and below the Boom Clay, the recently updated deep-aquifer pumping model, simulating transient flow in the over-exploited aquifers below the Boom Clay and finally the catchment-scale Neogene aquifer model, simulating flow in the aquifer system above the Boom Clay. The Neogene aquifer system consists of two main aquifers. The Pliocene aquifer is located at the top, separated from the underlying Miocene aquifer by the Kasterlee Clay aquitard. The Miocene aquifer consists of three hydrostratigraphic units: the Diest, Berchem and Voort Formations; with the last two having a lower hydraulic conductivity than the Diest unit. The transport model for the Neogene aquifer represents a fraction of the catchment-scale Neogene aquifer model. It stretches from the local divide between the Grote and Kleine Nete Rivers up to the Kleine Nete River, representing the main model sink. The boundary conditions and the sources/sinks in the Pliocene aquifer are defined mostly by the surface water features, such as the rivers, brooks, lakes and canals. In the partially confined Miocene aquifer, the effect of the surface water features is dampened and the heads at the model

  19. Water storage change estimation from in situ shrinkage measurements of clay soils

    OpenAIRE

    Brake, B.; M. J. van der Ploeg; Rooij, G. H.

    2012-01-01

    The objective of this study is to assess the applicability of clay soil elevation change measurements to estimate soil water storage changes, using a simplified approach. We measured moisture contents in aggregates by EC-5 sensors, and in multiple aggregate and inter-aggregate spaces (bulk soil) by CS616 sensors. In a long dry period, the assumption of constant isotropic shrinkage proved invalid and a soil moisture dependant geo...

  20. Simultaneous removal of multiple pesticides from water: effect of organically modified clays as coagulant aid and adsorbent in coagulation-flocculation process.

    Science.gov (United States)

    Shabeer, T P Ahammed; Saha, Ajoy; Gajbhiye, V T; Gupta, Suman; Manjaiah, K M; Varghese, Eldho

    2014-01-01

    Contamination of drinking water sources with agrochemical residues became a major concern in the twenty-first century. Coagulation-flocculation is the most widely used water-treatment process, but the efficiency to remove pesticides and other organic pollutants are limited compared to adsorption process. Thus, simultaneous action of adsorption on normal bentonite or organo-modified montmorillonite clays [modified with octadecylamine (ODA-M) and octadecylamine + amino-propyltriethoxysilane (ODAAPS-M)] followed by coagulation-flocculation by alum and poly aluminium chloride has been evaluated for removal of 10 different pesticides, namely atrazine, lindane, metribuzin, aldrin, chlorpyriphos, pendimethalin, alpha-endosulphan, beta-endosulphan, p,p'-DDT, cypermethrin and two of its metabolites, endosulphan sulphate and p,p'-DDE, from water. The coagulation without integration of adsorption was less effective (removal % varies from 12 to 49) than the adsorption-coagulation integrated system (removal % varies from 71 to 100). Further, coagulation integrated with adsorption was more effective when organically modified montmorillonite was used as adsorbent compared to normal bentonite. The removal efficiency of organic clay depends upon the concentration of pesticides, doses of clay minerals, and efficiency was more for ODAAPS-M as compared to ODA-M. The combination of ODAAPS-M-clay with coagulants was also used efficiently for the removal of pesticides from natural and fortified natural water collected and the results exhibit the usefulness of this remediation technique for application in water decontamination and in treatment of industrial and agricultural waste waters.

  1. Field experiments of Controlled Drainage of agricultural clay soils show positive effects on water quantity (retention, runoff) and water quality (nitrate leaching).

    Science.gov (United States)

    schipper, peter; stuyt, lodewijk; straat, van der, andre; schans, van der, martin

    2014-05-01

    Despite best management practices, agriculture is still facing major challenges to reduce nutrients leaching to the aquatic environment. In deltas, most of total nutrient losses from artificially drained agricultural soils are discharged via drains. Controlled drainage is a promising measure to prevent drainage of valuable nutrients, improve water quality and agricultural yield and adapt to climate change (reduce peak runoff, manage water scarcity and drought). In The Netherlands, this technique has attracted much attention by water managers and farmers alike, yet field studies to determine the expected (positive) effects for Dutch conditions were scarce. Recently, a field experiment was set up on clay soils. Research questions were: how does controlled, subsurface drainage perform on clay soils? Will deeper tile drains function just as well? What are the effects on drain water quality (especially with respect to nitrogen and salt) and crop yield? An agricultural field on clay soils was used to test different tile drainage configurations. Four types of tile drainage systems were installed, all in duplicate: eight plots in total. Each plot has its own outlet to a control box, where equipment was installed to control drain discharge and to measure the flow, concentrations of macro-ions, pH, nitrogen, N-isotopes and heavy metals. In each plot, groundwater observation wells and suction cups are installed in the saturated and vadose zones, at different depths, and crop yield is determined. Four plots discharge into a hydrologic isolated ditch, enabling the determination of water- and nutrient balances. Automatic drain water samplers and innovative nitrate sensors were installed in four plots. These enable identification and unravelling so-called first flush effects (changes in concentrations after a storm event). Water-, chloride- and nitrogen balances have been set up, and the interaction between groundwater and surface water has been quantified. The hydrological

  2. Water retention of rigid soils from a two-factor model for clay

    CERN Document Server

    Chertkov, V Y

    2014-01-01

    Water retention is one of the key soil characteristics. Available models of soil water retention relate to the curve-fitting type. The objective of this work is to suggest a physical model of water retention (drying branch) for soils with a rigid matrix. "Physical" means the prediction based on the a priori measured or estimated soil parameters with a clear physical meaning. We rely on the two-factor model of clay that takes into account the factors of capillarity and shrinkage. The key points of the model to be proposed are some weak pseudo shrinkage that the rigid soils demonstrate according to their experimental water retention curves, and some specific properties of the rigid grain matrix. The three input parameters for prediction of soil water retention with the rigid grain matrix include inter-grain porosity, as well as maximum and minimum grain sizes. The comparison between measured and predicted sand water retention curves for four different sands is promising.

  3. Considering Organic Carbon for Improved Predictions of Clay Content from Water Vapor Sorption

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per;

    2014-01-01

    Accurate determination of the soil clay fraction (CF) is of crucial importance for characterization of numerous environmental, agricultural, and engineering processes. Because traditional methods for measurement of the CF are laborious and susceptible to errors, regression models relating the CF...... carbon (OC) content and propose a modification to improve prediction accuracy. Evaluation of the CF prediction accuracy for 29 soils with clay contents ranging from 6 to 25% and with OC contents from 2.0 to 8.4% showed that the models worked reasonably well for all soils when the OC content was below 2...... to water vapor sorption isotherms that can be rapidly measured with a fully automated vapor sorption analyzer are a viable alternative. In this presentation we evaluate the performance of recently developed regression models based on comparison with standard CF measurements for soils with high organic...

  4. 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

    vapour sorption, which can be measured within a shorter period of time, have recently been developed. Such models are often based on single-point measurements of water adsorption and do not account for sorption hysteresis or organic matter content. The present study introduces regression relationships...... for estimating clay content from hygroscopic water at different relative humidity (RH) levels while considering hysteresis and organic matter content. Continuous adsorption/desorption vapour sorption isotherm loops were measured for 150 differently textured soils with a state-of-the-art vapour sorption analyser...

  5. Water dynamics in hectorite clays: Influence of temperature studied by coupling neutron spin echo and molecular dynamics

    International Nuclear Information System (INIS)

    Within the wider context of water behavior in soils, and with a particular emphasis on clays surrounding underground radioactive waste packages, we present here the translational dynamics of water in clays in low hydrated states as studied by coupling molecular dynamics (MD) simulations and quasielastic neutron scattering experiments by neutron spin echo (NSE). A natural montmorillonite clay of interest is modeled by a synthetic clay which allows us to understand the determining parameters from MD simulations by comparison with the experimental values.We focus on temperatures between 300 and 350 K, i.e., the range relevant to the highlighted application. The activation energy Ea experimentally determined is 6.6 kJ/mol higher than that for bulk water. Simulations are in good agreement with experiments for the relevant set of conditions, and they give more insight into the origin of the observed dynamics. (authors)

  6. Study of adsorption of zinc in clay smectite type Bofe in system of finite bath

    International Nuclear Information System (INIS)

    Clays are demonstrably excellent adsorbents, both for their physical and chemical characteristics and the wide coverage and low cost. Among the various groups of clay minerals, the smectite are noted for having large surface areas. The initial objective of this study was to characterize the clay Bofe through the techniques of X-Ray Diffraction (XRD), X-Ray Spectrometry by Energy Dispersive (EDX) and nitrogen adsorption (BET). To evaluate the adsorption of metal ions zinc (synthetic sewage), we used a system in finite bath, following a factorial design 22, taking as input variables: pH and initial concentrations of zinc (Zn2 +) and output variables: percentage removal and removal capacity. The characterization results showed that Bofe clay belongs to the family of smectite and therefore has great potential for adsorption. (author)

  7. Organic waste treatment with organically modified clays

    International Nuclear Information System (INIS)

    The use of organically modified clays in hazardous waste management applications offers a significant new and untapped potential. These clays may be used in the stabilization of organic wastes and organically contaminated soils, for waste water treatment, for oil spill control, for liner systems beneath fuel oil storage tanks, and as a component within liner systems of hazardous waste storage treatment and disposal facilities. Organically modified clays (organophilic clays) may be employed in each of these systems to adsorb organic waste constituents, enhancing the performance of the applications

  8. Adsorption of phenthoate and acetochlor from water by clays and organoclays

    Institute of Scientific and Technical Information of China (English)

    LIAO Min; XIE Xiao-mei

    2004-01-01

    Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as tetradecyltrimethyl ammonium bromide(TTAB), dodecyltrimethylammonium bromide(DTAB), and cetylpyridinium chloride(CPC) were studied. The adsorption equilibrium data points were fitted to Freundlich isotherm equations. The adsorption of phenthoate and acetochlor were significantly enhanced by surfactant treatment of the clays. The amount of both pesticides adsorbed per unit mass of organoclay followed the order of TTA-kaolin TTA(C14)-montmorillonite > DTA(C12)-montmorillonite. Phenthoate is adsorbed to greater extent than acetochlor by each adsorbent, which may be due to the higher hydrophobicity of phenthoate, indicating considerable hydrophobic interaction between adsorbent/adsorbate systems.

  9. Low resistivity oil(gas)-bearing reservoir conductive model --Dual water clay matrix conductive model in the north area of Tarim Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    潘和平; 王家映; 樊政军; 马勇; 柳建华; 李明强

    2001-01-01

    Shaly sands reservoir is one of the most distributive types of the oil(gas)-bearing reservoirs discovered in China, and low resistivity oil(gas)-bearing reservoirs are mostly shaly sands reservoirs. Therefore, shaly sands reservoir conductive model is the key to evaluate low resistivity oil(gas)-bearing reservoirs using logging information. Some defects were found when we studied the clay distribution type conductive model, dual-water conductive model, conductive rock matrix model, etc. Some models could not distinguish the conductive path and nature of microporosity water and clay water and some models did not consider the clay distribution type and the mount of clay volume. So, we utilize the merits,overcome the defects of the above models, and put forward a new shaly sands conductive model-dual water clay matrix conductive model (DWCMCM) in which dual water is the free water and the microporosity water in shaly sands and the clay matrix(wet clay) is the clay grain containing water. DWCMCM is presented here, the advantages of which can tell the nature and conductive path from different water (microporosity water and freewater), in consid-eration of the clay distribution type and the mount of clay volume in shaly sands. So, the results of logging interpretation in the oil(gas)-bearing reservoirs in the north of Tarim Basin area, China with DWCMCM are better than those interpreted by the above models.

  10. Effect of suction change on water content and total volume of an expansive clay

    Institute of Scientific and Technical Information of China (English)

    ZHAN Liang-tong; CHEN Ping; NG C.W.W.

    2007-01-01

    A laboratory study was carried out on both natural and compacted specimens to investigate the complex soil-water interaction in an unsaturated expansive clay. The laboratory study includes the measurement of soil-water characteristic curves, 1D free swelling tests, measurement of swelling pressure and shrinkage tests. The test results revealed that the air-entry value of the natural specimen was quite low due to cracks and fissures present. The hydraulic hysteresis of the natural specimen was relatively insignificant as compared with the compacted specimen. Within a suction range 0 to 500 kPa, a bilinear relationship between free swelling strain (or swelling pressure) and initial soil suction was observed for both the natural and compacted specimens. As a result of over-consolidation and secondary structures such as cementation and cracks, the natural specimens exhibited significant lower swelling (or swelling pressure) than the compacted specimen. The change of matric suction exerts a more significant effect on the water phase than on the soil skeleton for this expansive clay.

  11. Removal of clay from water wells by pneumatic-impulse method

    Energy Technology Data Exchange (ETDEWEB)

    Vol' nitskaya, E.M.; Lobachev, A.D.; Vorkin, I.A.; Zenkov, N.I.

    1983-01-01

    The pneumatic-impulse method of removing clay from water wells was carried out on the basis of the ASP-TM unit of the Ramenskiy department of the All-Union Scientific Research Institute of Geophysics. It was equipped with pneumatic line with winch, pneumatic chamber with control and measuring instruments, AK2-150 (or KR-2) electrical compressor and three high-pressure air cylinders (to 15 MPa) type 40-150U. The unit was used in wells with filter diameter over 90 mm. The essence of the method was periodic use of the effect of momentary transformation of compressed air energy with its severe expansion. The developing wave acts on the silt depositing zone of the filter and the rock in the bed, and partially or completely destroys it. Pneumatic treatment is done with pressure from 10 to 4 MPa with intensity of 10 pneumatic discharges per 1 running meter of filter. The method was tested in the Tyumen oblast when clay was removed from the filters of 16 exploratory and 5 exploratory-developmental wells made by rotary and impact-cable units. The increase in the total output of the well made by rotary method was 5 - 104% (with average about 70%). Higher increases in output are characteristic for wells that strip different-grained sands. When wells are drilled by impact-cable method and filters are installed in the aquiferous average- and large-grained sands, the pneumatic-impulse treatment is not very effective. With rotary drilling, clay removal from the filters and development of the aquiferous levels occur for 30-40 min. (with 3 h of preparatory work). Introduction of this method into the Tyumen oblast will improve the effectiveness of water prospecting by 20-50%.

  12. Adsorption of cobalt ions from waste water on activated Saudi clays

    Science.gov (United States)

    Al-Jlil, Saad A.

    2014-11-01

    The aim of this work was to remove the Cobalt ions from wastewater by three types of Saudi clay. These were collected from Tabbuk city (Tabbuk clay), Khiber city (Khiber clay), and Bahhah city (Bahhah clay). The paper also examined the effect of different activators on the enhancement of adsorption capacity of clays for cobalt ions. The results showed minor enhancement in the adsorption capacities of cobalt ions on three types of clays activated by acid treatment. The adsorption capacity of clays improved particularly for Tabbuk clay when treated with hydrogen peroxide as an activator. The adsorption capacity increased from 3.94 to 12.9 mg/g for the untreated and treated Tabbuk clay, respectively. Also, the adsorption capacity of Bahhah clay increased by activating with sodium chloride from 3.44 to 12.55 mg/g for untreated and treated sample, respectively. The equilibrium adsorption data were correlated using five equilibrium equations, namely, Langmuir, Freundlich, Langmuir-Freundlich, BET, and Toth isotherm equations. Langmuir isotherm agreed well with the experimental data of Khiber and Bahhah clay, while Freundlich model and Langmuir-Freundlich model fitted well with the experimental data of Tabbuk and Bahhah clay activated by NaCl. The results showed that Freundlich model fitted well with the experimental data of Tabbuk clay when activated by H2O2 and H2SO4. Finally, the BET model did not describe the experimental data well for the three types of clay after activation.

  13. Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

    Science.gov (United States)

    Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ≫ illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (Δs°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter

  14. Simulation of water movement and isoproturon behaviour in a heavy clay soil using the MACRO model

    Directory of Open Access Journals (Sweden)

    T. J. Besien

    1997-01-01

    Full Text Available In this paper, the dual-porosity MACRO model has been used to investigate methods of reducing leaching of isoproturon from a structured heavy clay soil. The MACRO model was applied to a pesticide leaching data-set generated from a plot scale experiment on a heavy clay soil at the Oxford University Farm, Wytham, England. The field drain was found to be the most important outflow from the plot in terms of pesticide removal. Therefore, this modelling exercise concentrated on simulating field drain flow. With calibration of field-saturated and micropore saturated hydraulic conductivity, the drain flow hydrographs were simulated during extended periods of above average rainfall, with both the hydrograph shape and peak flows agreeing well. Over the whole field season, the observed drain flow water budget was well simulated. However, the first and second drain flow events after pesticide application were not simulated satisfactorily. This is believed to be due to a poor simulation of evapotranspiration during a period of low rainfall around the pesticide application day. Apart from an initial rapid drop in the observed isoproturon soil residue, the model simulated isoproturon residues during the 100 days after pesticide application reasonably well. Finally, the calibrated model was used to show that changes in agricultural practice (deep ploughing, creating fine consolidated seed beds and organic matter applications could potentially reduce pesticide leaching to surface waters by up to 60%.

  15. Content and distribution of fluorine in rock, clay and water in fluorosis area Zhaotong, Yunnan Province

    Energy Technology Data Exchange (ETDEWEB)

    Luo, K.; Li, H.; Feng, F. (and others) [Chinese Academy of Sciences, Beijing (China)

    2007-04-15

    About 160 samples of coal, pyritic coal balls, coal seam gangue, clay, corn, capsicum and drinking water were collected from the endemic fluorosis area of Zhenxiong and Weixin county, China to determine the fluorine content, distribution pattern and source in this fluorosis area. The study shows that the average fluorine content in the coal samples collected from 3 coal mines of the Late Permian coals in Zhenxiong and Weixin county, Zhaotong City, which are the main mining coals there, is 77.13 mg/kg. The average fluorine content coals collected form thee typical fluorosis villages in 72.56 mg/kg. Both of them are close to the world average and little low than the Chinese average. The fluorine content of drinking water is lower than 0.35 mg/L, the clay used as an additive for coal-burning and as a binfer in briquette-making by local residents has a high content of fluorine, ranging from 367-2,435 mg/kg, with the majority higher than 600 mg/kg and an average of 1,084.2 mg/kg. 29 refs., 5 tabs.

  16. Refinements of water parameters for molecular dynamics: Simulations of adsorption at the clay mineral/aqueous solution interface

    DEFF Research Database (Denmark)

    Schäfer, L.; Yu, C.; Teppen, B.J.;

    1999-01-01

    In the context of a long-term program involving molecular dynamics simulations of adsorption phenomena at the clay mineral/aqueous solution interface, we are testing the viability of combining a force field that we developed specificially for clays with other, independently derived potential...... parameters for molecular species which are important in clay adsorption. For the current study the importance of variations in the potential parameters of water were investigated and polarization effects on oxygen studied as a function of intermolecular interactions. For this purpose ab initio MP2/6-311GG...... atomic charges were determined for several oligomers of water and for the water dimer at different intermolecular separations. Charge variations of up to ~0.1 electron charge unit on oxygen are found and, together with changes in van der Waals constants, their significance for dynamics simulations...

  17. Water and nutrient transport on a heavy clay soil in a fluvial plain in the Netherlands.

    Science.gov (United States)

    van der Salm, Caroline; van den Toorn, Antonie; Chardon, Wim J; Koopmans, Gerwin F

    2012-01-01

    In flat areas, transport of dissolved nutrients by water through the soil matrix to groundwater and drains is assumed to be the dominant pathway for nutrient losses to ground- and surface waters. However, long-term data on the losses of nutrients to surface water and the contribution of various pathways is limited. We studied nutrient losses and pathways on a heavy clay soil in a fluvial plain in The Netherlands during a 5-yr period. Average annual nitrogen (N) and phosphorus (P) losses to surface water were 15.1 and 3.0 kg ha(-1) yr(-1), respectively. Losses were dominated by particulate N (50%) and P (70%) forms. Rapid discharge through trenches was the dominant pathway (60-90%) for water and nutrient transport. The contribution of pipe drains to the total discharge of water and nutrients was strongly related to the length of the dry period in the preceding summer. This relationship can be explained by the very low conductivity of the soil matrix and the formation of shrinkage cracks during summer. Losses of dissolved reactive P through pipe drains appear to be dominated by preferential flow based on the low dissolved reactive P concentration in the soil matrix at this depth. Rainfall occurring after manure application played an important role with respect to the annual losses of N and P in spring when heavy rainfall occurred within 2 wk after manure application. PMID:22218191

  18. Water uptake by a clay bulkhead installed in the tunnel sealing experiment at Atomic Energy of Canada's underground research laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, D.A.; Martino, J.B.; Chandler, N.A. [Atomic Energy of Canada Ltd., AECL, Pinawa, MB (Canada); Sugita, Y. [Japan Nuclear Cycle, Development Institute, JNC, Tokai (Japan); Vignal, B. [Agence Nationale pour la Gestion des Dechets Radioactifs (ANDRA), 92 - Chatenay Malabry (France)

    2003-07-01

    A major international experiment, demonstrating technologies for tunnel sealing at full-scale, is being conducted at Canada's Underground Research Laboratory (URL) with participation by organizations from Canada, Japan, France and the U.S.A. Two bulkheads, one composed of high performance concrete and the other of highly compacted sand-bentonite material, have been constructed in a tunnel in unfractured granitic rock at the URL. The results from the Tunnel Sealing Experiment (TSX) are being used to characterize the performance of the two bulkheads under applied hydraulic pressures. The chamber between the two bulkheads has been pressurized to 4 MPa, a value representative of the natural hydrostatic heads at the 420 m depth below the ground surface. Instrumentation has been installed throughout the clay bulkhead to monitor stress development, bulkhead strain, moisture conditions, temperature, and water transport through this clay-based barrier. Construction was completed in 1998 October, and the sand-filled chamber between the clay and concrete bulkheads was filled and pressurized with water. Full pressure of 4 MPa was achieved in 2001 September and by 2002 June nearly complete saturation of the clay bulkhead was indicated. The rapid rate of saturation of the bulkhead (<5 years) is attributed initial large-flow events that caused a full perimeter water supply and allowed input of a considerable volume of water into the core of the bulkhead. Seepage through the clay bulkhead has been measured to be approximately 1.1 L/day under a 4 MPa pressure gradient across the 3.5 x 4.4 x 2.7 m length bulkhead. The majority of the seepage appears to be via the lower density outer perimeter of the bulkhead. Tracer tests have been completed which allow for assessment of flow times and pathways within the clay bulkhead. On achieving essentially full saturation, Phase 1 of the TSX was completed. A second phase of this experiment has recently (2002 June) begun with the

  19. Simulation Of Enhanced Reductive Dechlorination For Remediation Of Tce In A Fractured Clay System: A New Model Approach And Application To Field Site

    DEFF Research Database (Denmark)

    Manoli, Gabriele; Chambon, Julie Claire Claudia; Christiansen, Camilla Maymann;

    2010-01-01

    An innovative model is developed for Enhanced Reductive Dechlorination (ERD) of chlorinated solvents in a fractured glacial till. The model consists of three components: hydraulics, transport and degradation. The hydraulic component calculates the flow of water through a fractured clay till...... a contamination of trichloroethylene located in a fractured clay till. The site is simulated using the model developed. Fracture geometry, site parameters and degradation rates are based on observations from the site and lab studies. The risk for drinking water is assessed and cleanup times are simulated using...... model results. The spatial extent of remediation and downstream impact of the technology is evaluated. Perspectives for enhanced bioremediation technologies in fractured clay systems are discussed....

  20. Study of smectite clays of the city Pedra Lavrada - PB for use in water-based drilling fluids

    International Nuclear Information System (INIS)

    Paraiba has large reserves of bentonite clays, with the largest deposits in Boa Vista, PB. Recently new deposits were discovered in the cities of Cubati and Pedra Lavrada-PB, creating great expectations for further expansion of reserves for industrial production. The aim of this work is the study of smectite clays from the city of Pedra Lavrada, PB for use in drilling fluids water based. The characterization was made by the diffraction of laser (AG), thermogravimetric and differential thermal analysis (TGA and DTA), chemical composition by X-ray fluorescence (EDX), X-ray diffraction (XRD), exchange capacity of cations (ECC) and surface area (SA). The results obtained so far showed that the samples presented at its mineral composition smectite, kaolinite and quartz. In relation to rheological properties showed that the bentonite clay sample Dark presents promising features for use in water based drilling fluids. (author)

  1. Microwave-Assisted Preparation of Biodegradable Water Absorbent Polyacrylonitrile/Montmorillonite Clay Nanocomposite

    Directory of Open Access Journals (Sweden)

    Prafulla K. Sahoo

    2011-01-01

    Full Text Available Polyacrylonitrile (PAN/Montmorillonite (MMT clay nanocomposite was prepared in a microwave oven using a transition metal Co(III complex taking ammonium persulfate (APS as initiator with a motive of converting hydrophobic PAN into hydrophilic nanocomposite material via nanotechnology by the inclusion of MMT to the virgin polymer. UV-visible spectral analysis revealed various interactions between the developed complex with other reaction components. The formation of the PAN/MMT nanocomposites was characterized by FTIR. Furthermore, as evidenced by X-ray diffraction (XRD, transmission electron microscopy (TEM, the composite so obtained was found to have nano-order. XRD and TEM were suggesting that montmorillonite layers were exfoliated during the polymerization process. An increasing in the thermal stability for the developed nanocomposite was recorded by thermogravimetric analysis (TGA. The water absorption and biodegradation properties were carried out for its ecofriendly nature and better commercialization.

  2. Irrigation with saline-sodic water: effects on two clay soils

    Directory of Open Access Journals (Sweden)

    Giovanna Cucci

    2013-05-01

    Full Text Available The results of a 4-year experiment aimed at evaluating the effect of irrigation with saline-sodic water on the soil are reported. The research was carried out at the Campus of the Agricultural Faculty of Bari University (Italy on 2 clay soils (Bologna – T1 and Locorotondo – T2. The soils were cropped to borlotto bean (Phaseolus vulgaris L., capsicum (Capsicum annuum L., sunflower (Helianthus annuus L., wheat (Triticum durum Desf grown in succession; the crops were irrigated with 9 saline-sodic types of water and subjected to two different leaching fractions (10% and 20% of the watering volume. The 9 solutions were obtained dissolving in de-ionised water weighted amounts of sodium chloride (NaCl and calcium chloride (CaCl2, deriving from the combination of 3 saline concentrations and 3 sodicity levels. The crops were irrigated whenever the water lost by evapotranspiration from the soil contained in the pots was equal to 30% of the soil maximum available water. The results showed that, though the soils were leached during the watering period, they showed a high salt accumulation. Consequently, the saturated soil extract electrical conductivity increased from initial values of 0.65 and 0.68 dS m-1 to 11.24 and 13.61 dS m-1 at the end of the experiment, for the soils T1 and T2, respectively. The saline concentration increase in irrigation water caused in both soils a progressive increase in exchangeable sodium, and a decrease in exchangeable calcium and non-significant variations in exchangeable potassium (K and magnesium (Mg.

  3. Formation of polygonal fault systems as a result of hydrodynamical instabilities in clay-rich deposits.

    Science.gov (United States)

    Lopez, Teodolina; Antoine, Raphael; Rabinowicz, Michel; Baratoux, David; Darrozes, José; Kurita, Kei; D'Uston, Lionel

    2015-04-01

    Fine grained deposits as chalks and clays are characterised by the development of polygonal fault systems [1]. For the clay-rich deposits, two different environments are associated with their formation. First, on continents, dewatering leads to the development of polygonal desiccation cracks which have a centimetric to metric size [2]. Polygonal faults are also observed in sub-marine sedimentary deposits and here, can reach hectometric to kilometric size [3]. Since the giant polygons develop on basins with no clear evidences of tectonic stresses, the fracturing is attributed to stresses due to horizontal density variations generated during the basin subsidence. Several models have been proposed to explain the formation of the giant polygons and the two main hypotheses are the syneresis (spontaneous horizontal contraction) proposed by [4] and the low coefficient of friction of clay proposed by [5]. However, new understandings in the clay rheology and in the hydrodynamical instabilities, controlling the development of compaction in unconsolidated and consolidated clay deposits, permit us to propose an alternative hypothesis. We consider that the development of giant polygons results from the superposition of hydrodynamical instabilities leading to the formation of (i) mm-size agglomerates of clay particles while the deposit is unconsolidated [6], followed after by the consolidation of this layer, then (ii) hectometric to kilometric compaction spheres develop [7] and (iii) finally ends with the occurrence of hydrothermal and plastic convections. We show that the crucial conditions for the development of hectometric to kilometric size polygonal fault systems are: 1) the high permeability of the clay-rich deposit composed of mm-size agglomerates and 2) the dramatic increase of the strength of the clay as the deposit consolidates. [1] Dewhurst et al., (1999), Mar. Petr. Geol., 16 (8), 793-810. [2] Weinberger (1999), J. Struct. Geol., 21, 379-386. [3] Andresen and Huuse

  4. Non-selective oxidation of humic acid in heterogeneous aqueous systems: a comparative investigation on the effect of clay minerals.

    Science.gov (United States)

    Kavurmaci, Sibel Sen; Bekbolet, Miray

    2014-01-01

    Application of photocatalysis for degradation of natural organic matter (NOM) has received wide interest during the last decades. Besides NOM, model compounds more specifically humic acids (HAs) were also studied. As a continuation of the previous research, TiO2 photocatalytic degradation of HA was investigated in the presence of clay minerals, i.e., montmorillonite (Mt) and kaolinite (Kt). Degradation of HA was expressed by the pseudo-first-order kinetic modelling of dissolved organic carbon (DOC) and UV-VIS parameters (Colour436 and UV254). A slight rate enhancement was attained for Colour436 and UV254 in the presence of either Mt or Kt. The presence of clay particles did not significantly change the DOC degradation rate of HA. The effect of ionic strength (Ca2+ loading from 5 x 10(-4) M to 5 x 1(-3) M) was also assessed for the photocatalytic degradation of sole HA and HA in the presence of either Mt or Kt. Following photocatalytic treatment, molecular size distribution profiles of HA were presented. Besides the effective removal of higher molecular size fractions (100 and 30 kDa fractions), transformation to lower molecular size fractions (clay minerals. Scanning electron microscopic images with the energy dispersive X-ray analysis confirmed the diversities in surface morphologies of the binary and ternary systems composed of HA, TiO2 and Mt or Kt both prior to and following photocatalysis. This study demonstrated that photocatalysis could be applicable for DOC degradation in the presence of clay minerals in natural waters.

  5. Non-selective oxidation of humic acid in heterogeneous aqueous systems: a comparative investigation on the effect of clay minerals.

    Science.gov (United States)

    Kavurmaci, Sibel Sen; Bekbolet, Miray

    2014-01-01

    Application of photocatalysis for degradation of natural organic matter (NOM) has received wide interest during the last decades. Besides NOM, model compounds more specifically humic acids (HAs) were also studied. As a continuation of the previous research, TiO2 photocatalytic degradation of HA was investigated in the presence of clay minerals, i.e., montmorillonite (Mt) and kaolinite (Kt). Degradation of HA was expressed by the pseudo-first-order kinetic modelling of dissolved organic carbon (DOC) and UV-VIS parameters (Colour436 and UV254). A slight rate enhancement was attained for Colour436 and UV254 in the presence of either Mt or Kt. The presence of clay particles did not significantly change the DOC degradation rate of HA. The effect of ionic strength (Ca2+ loading from 5 x 10(-4) M to 5 x 1(-3) M) was also assessed for the photocatalytic degradation of sole HA and HA in the presence of either Mt or Kt. Following photocatalytic treatment, molecular size distribution profiles of HA were presented. Besides the effective removal of higher molecular size fractions (100 and 30 kDa fractions), transformation to lower molecular size fractions (clay minerals. Scanning electron microscopic images with the energy dispersive X-ray analysis confirmed the diversities in surface morphologies of the binary and ternary systems composed of HA, TiO2 and Mt or Kt both prior to and following photocatalysis. This study demonstrated that photocatalysis could be applicable for DOC degradation in the presence of clay minerals in natural waters. PMID:25145193

  6. Evidence and characteristics of a diverse and metabolically active microbial community in deep subsurface clay borehole water.

    Science.gov (United States)

    Wouters, Katinka; Moors, Hugo; Boven, Patrick; Leys, Natalie

    2013-12-01

    The Boom Clay in Belgium is investigated in the context of geological nuclear waste disposal, making use of the High Activity Disposal Experimental Site (HADES) underground research facility. This facility, located in the Boom Clay at a depth of 225 m below the surface, offers a unique access to a microbial community in an environment, of which all geological and geochemical characteristics are being thoroughly studied. This study presents the first elaborate description of a microbial community in water samples retrieved from a Boom Clay piezometer (borehole water). Using an integrated approach of microscopy, metagenomics, activity screening and cultivation, the presence and activity of this community are disclosed. Despite the presumed low-energy environment, microscopy and molecular analyses show a large bacterial diversity and richness, tending to correlate positively with the organic matter content of the environment. Among 10 borehole water samples, a core bacterial community comprising seven bacterial phyla is defined, including both aerobic and anaerobic genera with a range of metabolic preferences. In addition, a corresponding large fraction of this community is found cultivable and active. In conclusion, this study shows the possibility of a microbial community of relative complexity to persist in subsurface Boom Clay borehole water. PMID:23802615

  7. Adsorption potential of bentonite and attapulgite clays applied for the desalination of sea water

    OpenAIRE

    Nel, Monica; Waanders, Frans B.; Fosso-Kankeu, Elvis

    2014-01-01

    A possible new process for the partial desalination of seawater is to use bentonite clay or attapulgite as an adsorbent. The ion exchange property of these clays, which is a result of the characteristic t-o-t layer structure, enables the use of these materials as adsorbents. This technique has the opportunity to be used as a pre-treatment as current commercial seawater desalination processes are very expensive. The clay was characterized using XRD, XRF and SEM analyses. ...

  8. Water storage change estimation from in situ shrinkage measurements of clay soils

    Directory of Open Access Journals (Sweden)

    B. te Brake

    2013-05-01

    Full Text Available The objective of this study is to assess the applicability of clay soil elevation change measurements to estimate soil water storage changes, using a simplified approach. We measured moisture contents in aggregates by EC-5 sensors, and in multiple aggregate and inter-aggregate spaces (bulk soil by CS616 sensors. In a long dry period, the assumption of constant isotropic shrinkage proved invalid and a soil moisture dependant geometry factor was applied. The relative overestimation made by assuming constant isotropic shrinkage in the linear (basic shrinkage phase was 26.4% (17.5 mm for the actively shrinking layer between 0 and 60 cm. Aggregate-scale water storage and volume change revealed a linear relation for layers ≥ 30 cm depth. The range of basic shrinkage in the bulk soil was limited by delayed drying of deep soil layers, and maximum water loss in the structural shrinkage phase was 40% of total water loss in the 0–60 cm layer, and over 60% in deeper layers. In the dry period, fitted slopes of the ΔV–ΔW relationship ranged from 0.41 to 0.56 (EC-5 and 0.42 to 0.55 (CS616. Under a dynamic drying and wetting regime, slopes ranged from 0.21 to 0.38 (EC-5 and 0.22 to 0.36 (CS616. Alternating shrinkage and incomplete swelling resulted in limited volume change relative to water storage change. The slope of the ΔV–ΔW relationship depended on the drying regime, measurement scale and combined effect of different soil layers. Therefore, solely relying on surface level elevation changes to infer soil water storage changes will lead to large underestimations. Recent and future developments might provide a basis for application of shrinkage relations to field situations, but in situ observations will be required to do so.

  9. Microbial analyses of clay and water from different samples from the Mont Terri Rock Laboratory (RL), Switzerland

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Exploration of deep subsurface microbial life has increased for very diverse motives. One of them is that these environments are potential host rocks for radioactive waste repositories and that microorganisms may influence geochemical conditions around such sites and migration properties of radionuclides. The pore water Chemistry experiment (PC) was conducted at the Mont Terri-RL to measure in situ the pH, Eh, and other geochemical parameters within the pore water of the Opalinus Clay formation. The borehole for PC was drilled with N2 under clean but not aseptic conditions, filled immediately with synthetic pore water, which was circulated and monitored for five years. Soon after initiation of PC it was evident that microbial activity affected the borehole water geochemistry. Microbial analyses, including molecular biology and culturing methods, were performed repeatedly during PC (2003-2006), with detailed analysis of water and over-core clay upon termination in 2007. Results indicated the presence of heterotrophic aerobes and anaerobes, nitrate-reducers, iron-reducers, sulphate-reducers and Archaea, which together with geochemical data suggested a reducing environment with sulphate reduction in the water and adjacent clay. A black precipitate containing pyrite and a strong H2S smell confirmed the occurrence of sulphate reduction. Specific species identified (> 98% similarity) in PC water included Pseudomonas stutzeri, Bacillus licheniformis, and Desulfosporosinus sp., with similar and additional species (e.g., Trichococcus sp.; Koccuria sp.) in the clay. The origin of these (mostly anaerobic) species cannot be determined with certainty. Some species likely resulted from contamination, but others could be revived species indigenous in the Opalinus Clay. The microbial processes that occurred in PC are not representative of the processes in the undisturbed formation but illustrate the potential for microbial

  10. Error Analysis of Clay-Rock Water Content Estimation with Broadband High-Frequency Electromagnetic Sensors—Air Gap Effect

    Directory of Open Access Journals (Sweden)

    Thierry Bore

    2016-04-01

    Full Text Available Broadband electromagnetic frequency or time domain sensor techniques present high potential for quantitative water content monitoring in porous media. Prior to in situ application, the impact of the relationship between the broadband electromagnetic properties of the porous material (clay-rock and the water content on the frequency or time domain sensor response is required. For this purpose, dielectric properties of intact clay rock samples experimental determined in the frequency range from 1 MHz to 10 GHz were used as input data in 3-D numerical frequency domain finite element field calculations to model the one port broadband frequency or time domain transfer function for a three rods based sensor embedded in the clay-rock. The sensor response in terms of the reflection factor was analyzed in time domain with classical travel time analysis in combination with an empirical model according to Topp equation, as well as the theoretical Lichtenecker and Rother model (LRM to estimate the volumetric water content. The mixture equation considering the appropriate porosity of the investigated material provide a practical and efficient approach for water content estimation based on classical travel time analysis with the onset-method. The inflection method is not recommended for water content estimation in electrical dispersive and absorptive material. Moreover, the results clearly indicate that effects due to coupling of the sensor to the material cannot be neglected. Coupling problems caused by an air gap lead to dramatic effects on water content estimation, even for submillimeter gaps. Thus, the quantitative determination of the in situ water content requires careful sensor installation in order to reach a perfect probe clay rock coupling.

  11. Error Analysis of Clay-Rock Water Content Estimation with Broadband High-Frequency Electromagnetic Sensors--Air Gap Effect.

    Science.gov (United States)

    Bore, Thierry; Wagner, Norman; Lesoille, Sylvie Delepine; Taillade, Frederic; Six, Gonzague; Daout, Franck; Placko, Dominique

    2016-01-01

    Broadband electromagnetic frequency or time domain sensor techniques present high potential for quantitative water content monitoring in porous media. Prior to in situ application, the impact of the relationship between the broadband electromagnetic properties of the porous material (clay-rock) and the water content on the frequency or time domain sensor response is required. For this purpose, dielectric properties of intact clay rock samples experimental determined in the frequency range from 1 MHz to 10 GHz were used as input data in 3-D numerical frequency domain finite element field calculations to model the one port broadband frequency or time domain transfer function for a three rods based sensor embedded in the clay-rock. The sensor response in terms of the reflection factor was analyzed in time domain with classical travel time analysis in combination with an empirical model according to Topp equation, as well as the theoretical Lichtenecker and Rother model (LRM) to estimate the volumetric water content. The mixture equation considering the appropriate porosity of the investigated material provide a practical and efficient approach for water content estimation based on classical travel time analysis with the onset-method. The inflection method is not recommended for water content estimation in electrical dispersive and absorptive material. Moreover, the results clearly indicate that effects due to coupling of the sensor to the material cannot be neglected. Coupling problems caused by an air gap lead to dramatic effects on water content estimation, even for submillimeter gaps. Thus, the quantitative determination of the in situ water content requires careful sensor installation in order to reach a perfect probe clay rock coupling. PMID:27096865

  12. Controls of Ca/Mg/Fe activity ratios in pore water chemistry models of the Callovian-Oxfordian clay formation

    Energy Technology Data Exchange (ETDEWEB)

    Lerouge, C.; Grangeon, S.; Wille, G.; Flehoc, C.; Gailhanou, H.; Gaucher, E.C.; Tournassat, C. [BRGM av. Claude Guillemin BP6009 45060 Orleans cedex 2 (France); Vinsot, A. [ANDRA Meuse/Haute-Marne Underground research Laboratory (URL), RD 960, 55290 Bure (France); Made, B.; Altmann, S. [ANDRA - Parc de la Croix Blanche, 1-7 rue Jean Monnet, 92298 Chatenay-Malabry Cedex (France)

    2013-07-01

    In the pore water chemistry model of the Callovian-Oxfordian clay formation, the divalent cations Ca, Mg, and Fe are controlled by equilibrium reactions with pure carbonates: calcite for Ca, dolomite for Mg, and siderite for Fe. Results of a petrological study and computing of the Ca/Mg and Ca/Fe activity ratios based on natural pore water chemistry provide evidence that equilibrium with pure calcite and pure dolomite is a reasonable assumption for undisturbed pore waters; on the other hand, siderite cannot be considered at equilibrium with pore waters at the formation scale. (authors)

  13. Clays in prebiological chemistry

    Science.gov (United States)

    Rao, M.; Oro, J.; Odom, D. G.

    1980-01-01

    The ways in which clays have been utilized in studies of prebiological chemistry are reviewed, and an assessment is given of the possible role of clays in prebiological systems. The adsorption of organic molecules on clays has been demonstrated, as has the synthesis of bioorganic monomers in the presence of clays. For instance, amino acids, purines and pyrimidines have been obtained from carbon monoxide and nitric acid in the presence of clays at relatively high temperatures (250-325 C). The oligomerization of biochemical monomers, mediated by clays, has also been shown to result in the formation of polymer molecules basic to life. Clays have also been found to affect the condensation of mononucleotides to oligonucleotides.

  14. Exfoliation of clays in poly(dimethylsiloxane) rubber using an unexpected couple: a silicone surfactant and water.

    Science.gov (United States)

    Labruyère, Céline; Monteverde, Fabien; Alexandre, Michaël; Dubois, Philippe

    2009-04-01

    Poly(dimethylsiloxane) (PDMS)/montmorillonite (MMT) composites have been prepared using a newly synthesized omega-ammonium functionalized poly(dimethylsiloxane) compatibilizer coupled with a dispersion technique in water. The organoclay containing the new siloxane surfactant was characterized by TGA and XRD. For the first time, a nanoscopic dispersion of MMT nanoplatelets in the PDMS composite cured by hydrosilylation and a good compatibility between clay layers and matrix were obtained. The beneficial effect of both the surfactant and the water onto clay nanoplatelet dispersion was evaluated by different microscopy techniques and by measuring different properties such as the viscosity of the uncured PDMS/MMT nanodispersions, and the swelling rate and Young's modulus of the cured PDMS/MMT nanocomposites. PMID:19438028

  15. Estimated ground-water use in Becker, Clay, Douglas, Grant, Otter Tail, and Wilkin Counties, Minnesota, for 2030 and 2050

    Science.gov (United States)

    Winterstein, Thomas A.

    2007-01-01

    The U.S. Department of the Interior, Bureau of Reclamation, is studying six alternatives for delivering water to the Red River of the North Valley in North Dakota and to the cities of Breckenridge, Moorhead, and East Grand Forks, Minnesota. In order to evaluate these alternatives the Bureau of Reclamation needs estimates of ground-water use for 2030 and 2050 for six counties in Minnesota: Becker, Clay, Douglas, Grant, Otter Tail, and Wilkin Counties. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, conducted a study to estimate ground-water use in these counties for 2030 and 2050.

  16. Multi scale experimental study of water and ionic transport in porous charged media: clays; Etude experimentale multiechelle du transport ionique et aqueux en milieu poreux charge: argiles

    Energy Technology Data Exchange (ETDEWEB)

    Cadene, A

    2005-10-15

    Clays are porous media of industrial interest. Due to their retention capacities and low permeability to water, they are the principal candidate for the conception of engineered barriers radioactive waste disposal. The main interest of this study is the experimental determination of the cationic and water dynamics in montmorillonite and fluoro-hectorite at low water contents This latter synthetic smectite has been used as a model clay to help the interpretation of the results issued from the first natural one. After a summary on the clayey system, this work reports the many experimental techniques (Atomic Force Microscopy, Photo-Correlation Spectroscopy, Micro-calorimetry, Powder Diffraction) used during the preliminary study concerning structural characterisation of the samples. The study of the sodic form of smectites with the use of a combination of quasi-elastic neutron scattering techniques (Time of Flight and Spin Echo) succeeded to water diffusion coefficients but also to a discernment of the limits of such techniques. Experiments with montmorillonite samples are in agreement with the simulations, so tending to a validation of the models. Experimental data obtained from synthetic hectorites will be in the near future compared to simulations In the last part, this work shows the application of Broad Band Dielectric Spectroscopy for the investigation of ionic dynamic in these porous media. Many models have been developed for the interpretation of the experimental raw data obtained with this technique. (author)

  17. Mineral acquisition from clay by budongo forest chimpanzees

    NARCIS (Netherlands)

    Reynolds, Vernon; Lloyd, Andrew W.; English, Christopher J.; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

    2015-01-01

    Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consum

  18. Performance assessment of geological isolation systems for radioactive waste. Disposal in clay formations

    International Nuclear Information System (INIS)

    In the framework of the PAGIS project of the CEC Research Programme on radioactive waste, performance assessment studies have been undertaken on the geological disposal of vitrified high-level waste in clay layers at a reference site at Mol (B) and a variant site at Harwell (UK). The calculations performed for the reference site shown that most radionuclides decay to negligible levels within the first meters of the clay barrier. The maximum dose rates arising from the geological disposal of HLW, as evaluated by the deterministic approach are about 10-11 Sv/y for river pathways. If the sinking of a water well into the 150 m deep aquifer layer in the vicinity of the repository is considered together with a climatic change, the maximum calculated dose rate rises to a value of 3.10-7 Sv/y. The calculated maxima arise between 1 million and 15 million years after disposal. The maximum dose rates evaluated by stochastic calculations are about one order of magnitude higher due to the considerable uncertainties in the model parameters. In the case of the Boom clay the estimated consequences of a fault scenario are of the same order of magnitude as the results obtained for the normal evolution scenario. The maximum risk is estimated from stochastic calculations to be about 4.10-8 per year. For the variant site the case of the normal evolution scenario has been evaluated. The maximum dose rates calculated deterministically are about 1.10-6 Sv/y for river pathways and 6.10-5 Sv/y for a water well pathways; these doses would occur after about 1 million years. This document is one of a set of 5 reports covering a relevant project of the European Community on a nuclear safety subject having very wide interest. The five volumes are: the summary (EUR 11775-EN), the clay (EUR 11776-EN), the granite (EUR 11777-FR), the salt (EUR 11778-EN) and the sub-seabed (EUR 11779-EN)

  19. Salinity control in a clay soil beneath an orchard irrigated with treated waste water in the presence of a high water table: A numerical study

    Science.gov (United States)

    Russo, David; Laufer, Asher; Bardhan, Gopali; Levy, Guy J.

    2015-12-01

    A citrus orchard planted on a structured, clay soil associated with a high water table, irrigated by drip irrigation system using treated waste water (TWW) and local well water (LWW) was considered here. The scope of the present study was to analyze transport of mixed-ion, interacting salts in a combined vadose zone-groundwater flow system focusing on the following issues: (i) long-term effects of irrigation with TWW on the response of the flow system, identifying the main factors (e.g., soil salinity, soil sodicity) that control these effects, and (ii) salinity control aiming at improving both crop productivity and groundwater quality. To pursue this two-fold goal, 3-D numerical simulations of field-scale flow and transport were performed for an extended period of time, considering realistic features of the soil, water table, crop, weather and irrigation, and the coupling between the flow and the transport through the dependence of the soil hydraulic functions, K(ψ) and θ(ψ), on soil solution concentration C, and sodium adsorption ratio, SAR. Results of the analyses suggest that in the case studied, the long-term effect of irrigation with TWW on the response of the flow system is attributed to the enhanced salinity of the TWW, and not to the increase in soil sodicity. The latter findings are attributed to: (i) the negative effect of soil salinity on water uptake, and the tradeoff between water uptake and drainage flux, and, concurrently, solute discharge below the root zone; and, (ii) the tradeoff between the effects of C and SAR on K(ψ) and θ(ψ). Furthermore, it was demonstrated that a data-driven protocol for soil salinity control, based on alternating irrigation water quality between TWW and desalinized water, guided by the soil solution salinity at the centroid of the soil volume active in water uptake, may lead to a substantial increase in crop yield, and to a substantial decrease in the salinity load in the groundwater.

  20. Physical and numerical modeling of an inclined three-layer (silt/gravelly sand/clay) capillary barrier cover system under extreme rainfall.

    Science.gov (United States)

    Ng, Charles W W; Liu, Jian; Chen, Rui; Xu, Jie

    2015-04-01

    As an extension of the two-layer capillary barrier, a three-layer capillary barrier landfill cover system is proposed for minimizing rainfall infiltration in humid climates. This system consists of a compacted clay layer lying beneath a conventional cover with capillary barrier effects (CCBE), which is in turn composed of a silt layer sitting on top of a gravelly sand layer. To explore the effectiveness of the new system in minimizing rainfall infiltration, a flume model (3.0 m × 1.0 m × 1.1 m) was designed and set up in this study. This physical model was heavily instrumented to monitor pore water pressure, volumetric water content, surface runoff, infiltration and lateral drainage of each layer, and percolation of the cover system. The cover system was subjected to extreme rainfall followed by evaporation. The experiment was also back-analyzed using a piece of finite element software called CODE_BRIGHT to simulate transient water flows in the test. Based on the results obtained from various instruments, it was found that breakthrough of the two upper layers occurred for a 4-h rainfall event having a 100-year return period. Due to the presence of the newly introduced clay layer, the percolation of the three-layer capillary barrier cover system was insignificant because the clay layer enabled lateral diversion in the gravelly sand layer above. In other words, the gravelly sand layer changed from being a capillary barrier in a convention CCBE cover to being a lateral diversion passage after the breakthrough of the two upper layers. Experimental and back-analysis results confirm that no infiltrated water seeped through the proposed three-layer barrier system. The proposed system thus represents a promising alternative landfill cover system for use in humid climates. PMID:25582391

  1. Research and application of non-clay low damage temporary bridging drilling/completion fluids system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate (CaCO3) particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drillin...

  2. Gas migration through bentonitic engineered barrier systems and through non-indurated clays

    International Nuclear Information System (INIS)

    This extended abstract summarises briefly the main conclusions and perspectives of the research work carried out in the frame of gas migration from a radioactive waste disposal through bentonitic engineered barrier systems (EBS) and non-indurated natural clay formations. After a description of the most important experimental results and the conceptual model evolution, we will focus on the safety relevant issues and the way the gas migration through such media is currently treated in performance assessment for different types of waste. Finally, the remaining open questions will be addressed at the end of this paper. Further insights are provided in the EC/NEA status report. (authors)

  3. Modeling multi-component transport and enhanced anaerobic dechlorination processes in a single fracture-clay matrix system

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Broholm, Mette Martina; Binning, Philip John;

    2010-01-01

    of a contaminant in a single fracture-clay matrix system coupled with a reactive model for anaerobic dechlorination. The model takes into account microbially driven anaerobic dechlorination, where sequential Monod kinetics with competitive inhibition is used to model the reaction rates, and degradation...... is localized to account for potential pore size limitations on microbial entry to the clay matrix. The model is used to assess the distribution of TCE and its daughter products in the clay matrix and the concentration of the different compounds at the outlet of the fracture. The time frame for complete cleanup...... to the physical processes, mainly diffusion in the matrix, than to the biogeochemical processes, when dechlorination is assumed to take place in a limited reaction zone only. The inclusion of sequential dechlorination in clay fracture transport models is crucial, as the contaminant flux to the aquifer...

  4. Dynamics of water and ions in clays of type montmorillonite by microscopic simulation and quasi-elastic neutron scattering

    International Nuclear Information System (INIS)

    Montmorillonite clays in low hydration states, with Na+ and Cs+ compensating counter ions, are investigated by a combination of microscopic simulation and quasi-elastic neutron scattering to obtain information on the local structure and dynamics of water and ions in the interlayer. At first predictions of simulation into the dynamics of water and ions at elevate temperatures are shown (0 deg C 80 deg C, pertinent for the radioactive waste disposal scenario) Marked difference is observed between the modes of diffusion of the Na+ and C+ counter ions. In water dynamics, a significant step towards bulk water behaviour is seen on transition from the mono- to bilayer states. Secondly, a detailed comparison between simulation and quasi-elastic neutron scattering (Neutron Spin Echo and Time-of-Flight) regarding ambient temperature water dynamics is presented. Overall, the approaches are found to be in good agreement with each other and limitations of each of the methods are clearly shown. (author)

  5. Clay Houses

    Science.gov (United States)

    Pedro, Cathy

    2011-01-01

    In this article, the author describes a project designed for fourth-graders that involves making clay relief sculptures of houses. Knowing the clay houses will become a family heirloom makes this lesson even more worth the time. It takes three classes to plan and form the clay, and another two to underglaze and glaze the final products.

  6. Rapid nutrient leaching to groundwater and surface water in clay soil areas

    NARCIS (Netherlands)

    Bronswijk, J.J.B.; Hamminga, W.; Oostindie, K.

    1995-01-01

    The mechanism and magnitude of nitrate leaching from grassland on a heavy clay soil were investigated by measuring nitrogen input, and nitrate concentrations in groundwater and drain discharge for two years. A bromide tracer was applied to study solute transport mechanisms. Nitrate transport in the

  7. Water and clay based drilling fluids: rheologic, filtration and lubricity behavior; Fluidos hidroargilosos: comportamento reologico, de filtracao e lubricidade

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Luciana V.; Pereira, Melquesedek S.; Ferreira, Heber C. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    The aim of this work is to provide continuity for UFCG studies presenting results of rheological, filtration and the lubricity behaviors obtained with fluids prepared with bentonite clays from Paraiba, in binary compositions, after treatment with lubricants agents. It was selected two samples of bentonite clays and four lubricants (Lub 1, Lub 2, Lub 3 and Lub 4). The results showed that: depending on the composition, the drilling fluids presented bingham and pseudo plastic rheological behaviors, and with the additives bingham behavior; among the rheological and filtration properties evaluated, the apparent viscosity, yield limiting and the water loss are the have changes with the addition of lubricants; the values of the lubricity coefficient (LC) of fluids without additives were next of 0.50, independent of the composition of the bentonite clay mixture; after addition of the lubricants, the LC of fluids reduced for values next to 0,11, independent of its concentration and lubricants the best-performing are the Lub 2 and Lub 4. (author)

  8. Fate and transport of oil sand process-affected water into the underlying clay till: a field study.

    Science.gov (United States)

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S Jean; Moncur, Michael C; Ulrich, Ania C

    2013-08-01

    The South Tailings Pond (STP) is a ~2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes ((2)H and (18)O). The distribution of conservative tracers ((18)O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport. PMID:23752067

  9. Fate and transport of oil sand process-affected water into the underlying clay till: a field study.

    Science.gov (United States)

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S Jean; Moncur, Michael C; Ulrich, Ania C

    2013-08-01

    The South Tailings Pond (STP) is a ~2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes ((2)H and (18)O). The distribution of conservative tracers ((18)O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport.

  10. River water quality of the River Cherwell: an agricultural clay-dominated catchment in the upper Thames Basin, southeastern England.

    Science.gov (United States)

    Neal, Colin; Neal, Margaret; Hill, Linda; Wickham, Heather

    2006-05-01

    The water quality of the River Cherwell and a tributary of it, the Ray, are described in terms of point and diffuse sources of pollution, for this rural area of the upper Thames Basin. Point sources of pollution dominate at the critical ecological low flow periods of high biological activity. Although the surface geology is predominantly clay, base flow is partly supplied from springs in underlying carbonate-bearing strata, which influences the water quality particularly with regards to calcium and alkalinity. The hydrogeochemistry of the river is outlined and the overall importance of urban point sources even in what would normally be considered to be rural catchments is stressed in relation to the European Unions Water Framework Directive. Issues of phosphorus stripping at sewage treatment works are also considered: such stripping on the Cherwell has reduced phosphorus concentrations by about a factor of two, but this is insufficient for the needs of the Water Framework Directive. PMID:16253306

  11. On The Thermal Consolidation Of Boom Clay

    CERN Document Server

    Delage, Pierre; Cui, Yu-Jun

    2012-01-01

    When a mass of saturated clay is heated, as in the case of host soils surrounding nuclear waste disposals at great depth, the thermal expansion of the constituents generates excess pore pressures. The mass of clay is submitted to gradients of pore pressure and temperature, to hydraulic and thermal flows, and to changes in its mechanical properties. In this work, some of these aspects were experimentally studied in the case of Boom clay, so as to help predicting the response of the soil, in relation with investigations made in the Belgian underground laboratory at Mol. Results of slow heating tests with careful volume change measurements showed that a reasonable prediction of the thermal expansion of the clay-water system was obtained by using the thermal properties of free water. In spite of the density of Boom clay, no significant effect of water adsorption was observed. The thermal consolidation of Boom clay was studied through fast heating tests. A simple analysis shows that the hydraulic and thermal trans...

  12. Static and dynamic filtrations of different clay, electrolytes, polymer systems; Filtrations statiques et dynamiques de differents systemes argile, electrolytes, polymere

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.

    1996-04-16

    Filtration properties of model drilling fluids composed of water, clays, electrolytes and water soluble polymers have been studied in static and dynamic conditions on paper filters and rock slices. Filtration experiments combined with cake observations by cryo-S.E.M. and T.E.M., show the influence of the size shape of clay particles as well as their associating mode in suspension, on the texture of the cake, its permeability, and relaxation properties. These parameters depend on the nature of the electrolyte. The polymer reduces the cake permeability by enhancing the dispersion of the clay within the suspension, but mainly by plugging the porous network due its auto aggregation properties. The cake construction in dynamic conditions, is related to the state of aggregation of the initial suspension, its poly-dispersity, its sensitivity to shear rates, and also, to the permeability of the cake built at the beginning of the filtration. In all cases, the rate of thickening of the cake is slower and larger filtrate volumes are obtained compared to the static conditions. Shear rate has two effects: first, to dissociate the weak aggregates in suspension, second, to impose a size selection of the particles in the case of a poly-dispersed suspension. At high shear rates, a cake of constant thin thickness is quickly obtained. The thickness of this limiting cake depends on the fraction of small particles present in suspension, or that can be formed by dissociation of weak aggregates under shear rate. The permeability of this limiting cake formed in dynamic conditions is, as in static conditions, controlled by the size and the shape of the particles that form the cake or by the presence of a build loss reducer water soluble polymer. Filtrations carried out on Fontainebleau sandstones allow to visualize the internal cake and to precise the risks of formation damage by the drilling fluid. (author) 127 refs.

  13. Hypoplastic model for simulation of compressibility characteristics of cement-admixed Bangkok soft clay at high water content

    Science.gov (United States)

    Chattonjai, Piyachat

    2016-06-01

    The developed hypoplastic model for simulation of compressibility characteristics of cement-admixed Bangkok soft clay at high water content was proposed in this paper. By using unique equation, the model is able to predict the relationship between void ratio and vertical effective stress of different water and cement content of soil cement. For practically convenient utilization and understanding, the parameters of Q1 which represented to initial cement bonding of soil (the initial value of structure tensor at time = 0) and C2 which effected to the model stiffness on isotropic consolidation direction, at 45° for loading and 225° for unloading of stress response envelope, were proposed as the function of cement and water content by comparing with dry weight of soil. By numerical integration that satisfied one-dimensional settlement, the simulation results were directly compared with fifteen experimental results to verify the accuracy of the proposed model.

  14. Factors affecting the design of slow release formulations of herbicides based on clay-surfactant systems. A methodological approach.

    Directory of Open Access Journals (Sweden)

    María Del Carmen Galán-Jiménez

    Full Text Available A search for clay-surfactant based formulations with high percentage of the active ingredient, which can yield slow release of active molecules is described. The active ingredients were the herbicides metribuzin (MZ, mesotrione (MS and flurtamone (FL, whose solubilities were examined in the presence of four commercial surfactants; (i neutral: two berols (B048, B266 and an alkylpolyglucoside (AG6202; (ii cationic: an ethoxylated amine (ET/15. Significant percent of active ingredient (a.i. in the clay/surfactant/herbicide formulations could be achieved only when most of the surfactant was added as micelles. MZ and FL were well solubilized by berols, whereas MS by ET/15. Sorption of surfactants on the clay mineral sepiolite occurred mostly by sorption of micelles, and the loadings exceeded the CEC. Higher loadings were determined for B266 and ET/15. The sorption of surfactants was modeled by using the Langmuir-Scatchard equation which permitted the determination of binding coefficients that could be used for further predictions of the sorbed amounts of surfactants under a wide range of clay/surfactant ratios. A possibility was tested of designing clay-surfactant based formulations of certain herbicides by assuming the same ratio between herbicides and surfactants in the formulations as for herbicides incorporated in micelles in solution. Calculations indicated that satisfactory FL formulations could not be synthesized. The experimental fractions of herbicides in the formulations were in agreement with the predicted ones for MS and MZ. The validity of this approach was confirmed in in vitro release tests that showed a slowing down of the release of a.i. from the designed formulations relative to the technical products. Soil dissipation studies with MS formulations also showed improved bioactivity of the clay-surfactant formulation relative to the commercial one. This methodological approach can be extended to other clay-surfactant systems for

  15. The electrochemistry of carbon steel in simulated concrete pore water in boom clay repository environments

    Directory of Open Access Journals (Sweden)

    Rosas-Camacho O.

    2011-04-01

    Full Text Available The prediction of corrosion damage of canisters to experimentally inaccessible times is vitally important in assessing various concepts for the disposal of High Level Nuclear Waste. Such prediction can only be made using deterministic models, whose predictions are constrained by the time-invariant natural laws. In this paper, we describe the measurement of experimental electrochemical data that will allow the prediction of damage to the carbon steel overpack of the super container in Belgium’s proposed Boom Clay repository by using the Point Defect Model (PDM. PDM parameter values are obtained by optimizing the model on experimental, wide-band electrochemical impedance spectroscopy data.

  16. Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in shallow, recently recharged ground water -- Input data set for clay sediment (gwava-s_clay)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the amount of clay sediment in the soil, in percent times 1000, in the conterminous United States. The data set was used as an input data...

  17. Planning of experimental removal of cadmium in finite bath system using the chocolate clay B as adsorbent

    International Nuclear Information System (INIS)

    The smectite clays are characterized by having a high cation exchange capacity and ability to remove metal ions. They have great industrial importance, for its abundance and low cost. The first part of this work was to characterize the clay called Chocolate B through the techniques of X-Ray Diffraction, X-Ray Spectroscopy and Energy Dispersive Physical Adsorption of Nitrogen. The second part of the work aims to evaluate the significance of the variables: pH and initial concentration on removal of cadmium in a batch system. In the experimental design used was a 22 factorial analysis with the addition at the central point, and evaluated the percentage of removal (Rem%) and removal capacity (EQF). XRD results corroborating the chemical analysis (EDX), characterized as a B Chocolate smectite clays. Statistical analysis showed a strong influence of variable pH on the removal of cadmium. (author)

  18. Clay properties

    NARCIS (Netherlands)

    De Wit, P.J.

    1992-01-01

    In this report an overview will be given of the basic properties of (suspended) clay particles. In section 2 the structure of clay minerals will be described. The forces between suspended particles (section 3) and the possible consequences of them, flocculation or deflocculation (sections 4 and 5) w

  19. The 1.7- to 4.2-micron spectrum of asteroid 1 Ceres - Evidence for structural water in clay minerals

    Science.gov (United States)

    Lebofsky, L. A.; Feierberg, M. A.; Larson, H. P.; Johnson, J. R.; Tokunaga, A. T.

    1981-01-01

    A high-resolution Fourier spectrum (1.7-3.5 microns) and medium-resolution spectrophotometry (2.7-4.2 microns) were obtained for Asteroid 1 Ceres. The presence of the 3-micron absorption feature due to water of hydration was confirmed. The 3-micron feature is compared with the 3-micron bands due to water of hydration in clays and salts. It is concluded that the spectrum of Ceres shows a strong absorption at 2.7-2.8 microns due to structural OH groups in clay minerals. The dominant minerals on the surface of Ceres are therefore hydrated clay minerals structurally similar to terrestrial montmorillonites. There is also a narrow absorption feature at 3.1 microns which is attributable to a very small amount of water ice on Ceres. This is the first evidence for ice on the surface of an asteroid.

  20. Clays in natural and engineered barriers for radioactive waste confinement

    International Nuclear Information System (INIS)

    The meeting covers all topics concerning natural argillaceous geological barriers and the clay material based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties). The works presented deal with: examples of broad research programs (national or international) on the role of natural and artificial clay barriers for radionuclide confinement; clay-based repository concepts: repository designs, including technological and safety issues related to the use of clay for nuclear waste confinement; geology and clay characterisation: mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in rock clay, fracturing, self sealing processes, role of organic matter and microbiological processes; geochemistry: pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry; mass transfer: water status and hydraulic properties in low permeability media, pore space geometry, water, solute and gas transfer processes, colloid mediated transport, large scale movements, long-term diffusion; alteration processes: oxidation effects, hydration-dehydration processes, response to thermal stress, iron-clay interactions, alkaline perturbation; geomechanics: thermo-hydro-mechanical behaviour of clay, rheological models, EDZ characterisation and evolution, coupled behaviour and models (HM, THM, THMC). A particular interest is given to potential contributions coming from fields of activities other than radioactive waste management, which take advantage of the confinement properties of the clay barrier (oil and gas industries, gas geological storage, CO2 geological sequestration, chemical waste isolation

  1. Clays in natural and engineered barriers for radioactive waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The meeting covers all topics concerning natural argillaceous geological barriers and the clay material based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties). The works presented deal with: examples of broad research programs (national or international) on the role of natural and artificial clay barriers for radionuclide confinement; clay-based repository concepts: repository designs, including technological and safety issues related to the use of clay for nuclear waste confinement; geology and clay characterisation: mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in rock clay, fracturing, self sealing processes, role of organic matter and microbiological processes; geochemistry: pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry; mass transfer: water status and hydraulic properties in low permeability media, pore space geometry, water, solute and gas transfer processes, colloid mediated transport, large scale movements, long-term diffusion; alteration processes: oxidation effects, hydration-dehydration processes, response to thermal stress, iron-clay interactions, alkaline perturbation; geomechanics: thermo-hydro-mechanical behaviour of clay, rheological models, EDZ characterisation and evolution, coupled behaviour and models (HM, THM, THMC). A particular interest is given to potential contributions coming from fields of activities other than radioactive waste management, which take advantage of the confinement properties of the clay barrier (oil and gas industries, gas geological storage, CO{sub 2} geological sequestration, chemical waste isolation

  2. Performance Evaluation of Different Tillage Systems in a Clay Loam Soil

    International Nuclear Information System (INIS)

    Field experiments were conducted to assess the performance of different tillage systems in a clay loam soil. A completely randomized block design with four treatments i.e., conventional tillage (CT), minimum tillage (MT), zero tillage (ZT) and controlled traffic farming (CTF) was carried out to evaluate the performance of tillage systems. Results indicated that the soil pulverization was higher (P<0.05) under MT and lower under CT treatments while, it was non-significant between MT and CTF treatments. Similarly, soil volume disturbed and effective ploughing depth was maximum (P<0.05) under CT followed by MT, CTF and minimum under ZT. Similarly the operating speed was significantly higher (P<0.05) under CTF and lower under CT whereas, wheel slippage/travel reduction was significantly minimum (P<0.05) under CTF and maximum under CT. Significantly, higher field capacity was recorded under CTF and lower (P<0.05) under CT. The maximum fuel consumption (P<0.05) was recorded under CT while it was minimum under ZT. Almost similar trends were observed for all parameters in 2012 and 2013. The results suggested that the control traffic system was more efficient tillage system in terms of soil pulverization, operating speed, travel reduction and over all field capacity. While, zero tillage had minimum fuel consumption and conventional tillage had higher working depth hence, more soil volume was disturbed under this treatment. (author)

  3. Water and solute transport in agricultural soils predicted by volumetric clay and silt contents

    DEFF Research Database (Denmark)

    Karup, Dan; Møldrup, Per; Paradelo Pérez, Marcos;

    2016-01-01

    (particles ≤ 50 μm). The results showed that the mineral fines content was strongly correlated to functional soil structure and the derived tracer breakthrough curve (BTC), whereas the OC content appeared less important for the shape of the BTC. Organic carbon was believed to support the stability...... of the soil structure rather than the actual formation of macropores causing preferential flow. The arrival times of 5 % and up to 50 % of the tracer mass were found to be strongly correlated with volumetric fines content. The hereby predicted tracer concentration breakthrough points up to 50% of applied...... tracer mass could be well fitted to an analytical solution to the classical convection-dispersion equation. Both cumulative tracer mass and concentration as a function of time were hereby reasonable well predicted from the simple inputs of bulk density, clay and silt contents, and applied tracer mass...

  4. Tropical dryland agroforestry on clay soils: : Analysis of systems based on Acacia senegal in the Blue Nile region, Sudan

    OpenAIRE

    Raddad, Elamin Yousif Abdalla

    2006-01-01

    Acacia senegal, the gum arabic producing tree, is the most important component in traditional dryland agroforestry systems in the Blue Nile region, Sudan. The aim of the present study was to provide new knowledge on the potential use of A. senegal in dryland agroforestry systems on clay soils, as well as information on tree/crop interaction, and on silvicultural and management tools, with consideration on system productivity, nutrient cycling and sustainability. Moreover, the aim was also to ...

  5. Impact of Air Oxidation on Dissolved Organic Matter from Boom Clay: Comparison Between Natural and Artificial Oxidation Series and In Situ Piezometers Water From Hades Galleries

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The Boom Clay is considered by the Belgian radioactive waste management agency Ondraf/Niras as a possible host rock for the geological disposal of high-level and long-lived radioactive waste. The drilling of galleries and corings in the Boom Clay (Mol, Belgium) leads to perturbations of the initial physical and chemical conditions. In piezometers, the DOC may show considerable and irregular variations through time, with values ranging from 80 to 425 mg/L. The origin and bio-physico-chemical controls of such variations are yet unknown but oxidation and biodegradation were considered as most likely. Three categories of samples were collected with the aim of determining and quantifying different molecular markers representative for the oxidation process: - Fresh as well as air-oxidized Boom Clay samples were collected in the Underground Research Facility HADES of EURIDICE (Mol, Belgium): they represent a natural series of oxidation; - A fresh Boom Clay sample was submitted to laboratory air oxidation (artificial series). In these experiments, powdered clay was heated at 80 deg. C under air flow during 1, 3, 6, 9, 12, 18 months; - Four water samples were collected during January 2010 from different horizons in the Boom Clay by means of piezometers located in the Underground Research Facility. The DOM (dissolved organic matter) of Boom Clay samples (artificial and natural series) was isolated by Soxhlet using pure water as well as by leaching experiments. The quantitative analysis shows an increasing in DOC (Dissolved Organic Carbon) content with oxidation. Qualitative characterizations including spectroscopic (3D-fluorescence) as well as molecular analyses (flash pyrolysis - gas chromatography - mass spectrometry (PyGC-MS) and size exclusion chromatography (SEC-HPLC)) show an evolution of the DOM chemistry with oxidation: - An enrichment in oxygen bearing molecules (acidic poly functional groups); - A decrease in

  6. Water and solute transport in agricultural soils predicted by volumetric clay and silt contents

    Science.gov (United States)

    Karup, Dan; Moldrup, Per; Paradelo, Marcos; Katuwal, Sheela; Norgaard, Trine; Greve, Mogens H.; de Jonge, Lis W.

    2016-09-01

    Solute transport through the soil matrix is non-uniform and greatly affected by soil texture, soil structure, and macropore networks. Attempts have been made in previous studies to use infiltration experiments to identify the degree of preferential flow, but these attempts have often been based on small datasets or data collected from literature with differing initial and boundary conditions. This study examined the relationship between tracer breakthrough characteristics, soil hydraulic properties, and basic soil properties. From six agricultural fields in Denmark, 193 intact surface soil columns 20 cm in height and 20 cm in diameter were collected. The soils exhibited a wide range in texture, with clay and organic carbon (OC) contents ranging from 0.03 to 0.41 and 0.01 to 0.08 kg kg- 1, respectively. All experiments were carried out under the same initial and boundary conditions using tritium as a conservative tracer. The breakthrough characteristics ranged from being near normally distributed to gradually skewed to the right along with an increase in the content of the mineral fines (particles ≤ 50 μm). The results showed that the mineral fines content was strongly correlated to functional soil structure and the derived tracer breakthrough curves (BTCs), whereas the OC content appeared less important for the shape of the BTC. Organic carbon was believed to support the stability of the soil structure rather than the actual formation of macropores causing preferential flow. The arrival times of 5% and up to 50% of the tracer mass were found to be strongly correlated with volumetric fines content. Predicted tracer concentration breakthrough points as a function of time up to 50% of applied tracer mass could be well fitted to an analytical solution to the classical advection-dispersion equation. Both cumulative tracer mass and concentration as a function of time were well predicted from the simple inputs of bulk density, clay and silt contents, and applied tracer

  7. Development of shot-clay system to construct high-quality buffer materials

    International Nuclear Information System (INIS)

    This paper describes the result of an experiment of shot-clay method which has been developed to construct the high-quality buffer materials in a radioactive waste disposal facility. The shot-clay method is a construction method which is conducted by shooting particle-like bentonite material with the supplied energy of high-pressured air. This paper includes a basic idea of this method, features, and results of its key experiments. (authors)

  8. Research and application of non-clay low damage temporary bridging drilling/completion fluids system

    Institute of Scientific and Technical Information of China (English)

    Xiang-zhe Jin; Zai-jun Chen; Bin Yang

    2009-01-01

    Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology, inert calcium carbonate (CaCO3) particles, whose diameter is consistent with the size of pores or apertures in the reservoir, were selected as the bridging agent, and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drilling, NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours, respectively, and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability. The results showed that the permeability recovery rate of the core reached 90% or so, and the damaged depth was less than 1 cm, which demonstrates that NL TDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system. NLTDFS has been used to drill many horizontal wells, and four of them have obtained high yield of natural gas. The yield of natural gas of LPl well reached 85 X 104 m3/day after completion with the rump pipe. The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.

  9. Dissolution Behaviour of UO2 in Anoxic Conditions: Comparison of Ca-Bentonite and Boom Clay

    International Nuclear Information System (INIS)

    In order to determine in how far the clay properties influence the dissolution of spent fuel, experiments were carried out with depleted UO2 in the presence of either compacted dry Ca-bentonite with Boom Clay groundwater (KB-BCW) or compacted dry Boom Clay with Boom Clay groundwater (BC-BCW). The leach tests were performed at 25 deg. C in anoxic atmosphere for 2 years. The U concentrations in the clay water were followed during these 2 years, and the amount of U in the clay was determined after 2 years in order to determine the UO2 dissolution rate. The uranium concentration after 0.45 μm filtration was 50 times higher in the Boom Clay with Boom Clay water (2.0 x 10-7 mol.L-1) than in Ca-bentonite with Boom Clay water (6.5 x 10-9 mol.L-1), probably due to colloid formation in the Boom Clay system. Most released uranium was found in the clay. The fraction of uranium, dissolved from the UO2 pellet and found on the clay represents about 42 % of total uranium release in the system BC-BCW and more than 76 % in the system KB-BCW. The higher uranium retention of Boom Clay goes together with a higher dissolution rate. Global dissolution rates were estimated at about 2.0 x 10-2 μg.cm-2.d-1 for the BCBCW system and 3.4 x 10-3 μg.cm-2.d-1 for the KB-BCW system. This is not much lower than for similar tests with spent fuel, reported in literature. (authors)

  10. radiochemical studies on the use of local clays and some other sorbents for water purification

    International Nuclear Information System (INIS)

    the search for clean water is a problem for every body where without water there is no life, no agriculture, no industry. in many fresh waters, metals concentrations are elevated by domestic and industrial sewage or other sources. some metals are essential for organisms, but they are toxic in high concentrations. the presence of trace elements and heavy metals in drinking waters is of concern from a health-related aspect, since these elements have been linked to the occurrence of human cancer in many instances, in addition to the probable toxicity. the search of methods for decontamination of water is of great concern. the use of pottery for refrigeration of water is an old traditional famous method used for many centuries. people used pottery for refrigeration did not realize that this material is a good decontaminating sorbent and their water is purified from the harmful metal ions. therefore, the aim of this thesis is to examine the use of different kinds of pottery, as natural cheap sorbent, for decontamination of water from heavy and toxic metallic ions such as; Co2+,fe3+,Cs+,Cd2+,Cr3+, zn2+, Pb2+, Mg2+, and Cu2+, and to find the effect of some additives known to be present in water, such as humic acid and fulvic acid or those added to water for refining and sterilization such as alum, chlorine and KMnO4. four water supplies and three kinds of pottery were selected for the study

  11. Coupled modelling (transport-reaction) of the fluid-clay interactions and their feed back on the physical properties of the bentonite engineered clay barrier system; Modelisation couplee (transport - reaction) des interactions fluides - argiles et de leurs effets en retour sur les proprietes physiques de barrieres ouvragees en bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Marty, N

    2006-11-15

    The originality of this work is to process feed back effects of mineralogical and chemical modifications of clays, in storage conditions, on their physical properties and therefore on their transport characteristics (porosity, molecular diffusion, permeability). These feed back effects are modelled using the KIRMAT code (Kinetic of Reaction and MAss Transfer) developed from the kinetic code KINDIS by adding the effect of water renewal in the mineral-solution reactive cells. KIRMAT resolves mass balance equations associated with mass transport together with the geochemical reactions in a 1D approach. After 100 000 years of simulated interaction at 100 C, with the fluid of the Callovo-Oxfordian geological level (COX) and with iron provided by the steel overpack corrosion, the montmorillonite of the clay barrier is only partially transformed (into illite, chlorite, saponite...). Only outer parts of the modelled profile seem to be significantly affected by smectite dissolution processes, mainly at the interface with the geological environment. The modifications of physical properties show a closure of the porosity at the boundaries of the barrier, by creating a decrease of mass transport by molecular diffusion, essentially at the interface with the iron. Permeability laws applied to this system show a decrease of the hydraulic conductivity correlated with the porosity evolution. Near the COX, the swelling pressure of the clays from the barrier decreases. In the major part of the modelled profile, the engineered clay barrier system seems to keep its initial physical properties (porosity, molecular diffusion, permeability, swelling pressure) and functionalities. (author)

  12. NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs

    Directory of Open Access Journals (Sweden)

    Vincenzo Baglio

    2012-06-01

    Full Text Available Water and methanol transport behavior, solvents adsorption and electrochemical properties of filler-free Nafion and nanocomposites based on two smectite clays, were investigated using impedance spectroscopy, DMFC tests and NMR methods, including spin-lattice relaxation and pulsed-gradient spin-echo (PGSE diffusion under variable temperature conditions. Synthetic (Laponite and natural (Swy-2 smectite clays, with different structural and physical parameters, were incorporated into the Nafion for the creation of exfoliated nanocomposites. Transport mechanism of water and methanol appears to be influenced from the dimensions of the dispersed platelike silicate layers as well as from their cation exchange capacity (CEC. The details of the NMR results and the effect of the methanol solution concentration are discussed. Clays particles, and in particular Swy-2, demonstrate to be a potential physical barrier for methanol cross-over, reducing the methanol diffusion with an evident blocking effect yet nevertheless ensuring a high water mobility up to 130 °C and for several hours, proving the exceptional water retention property of these materials and their possible use in the DMFCs applications. Electrochemical behavior is investigated by cell resistance and polarization measurements. From these analyses it is derived that the addition of clay materials to recast Nafion decreases the ohmic losses at high temperatures extending in this way the operating range of a direct methanol fuel cell.

  13. Lake responses following lanthanum-modified bentonite clay (Phoslock) application: an analysis of water column lanthanum data from 16 case study lakes

    NARCIS (Netherlands)

    Spears, B.M.; Lürling, M.F.L.L.W.; Yasseri, S.; Castro-Castellon, A.T.; Gibbs, M.; Meis, S.; McDonald, C.; McIntosh, J.; Sleep, D.; Oosterhout, van F.

    2013-01-01

    Phoslock is a lanthanum (La) modified bentonite clay that is being increasingly used as a geo-engineering tool for the control of legacy phosphorus (P) release from lake bed sediments to overlying waters. This study investigates the potential for negative ecological impacts from elevated La concentr

  14. Permeameter studies of water flow through cement and clay borehole seals in granite, basalt and tuff

    Energy Technology Data Exchange (ETDEWEB)

    South, D.L.; Daemen, J.J.K.

    1986-10-01

    Boreholes near a repository must be sealed to prevent rapid migration of radionuclide-contaminated water to the accessible environment. The objective of this research is to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. Flow through a sealed borehole is compared with flow through intact rock. Cement or bentonite seals have been tested in granite, basalt, and welded tuff. The main conclusion is that under laboratory conditions, existing commercial materials can form high quality seals. Triaxial stress changes about a borehole do not significantly affect seal performance if the rock is stiffer than the seal. Temperature but especially moisture variations (drying) significantly degrade the quality of cement seals. Performance partially recovers upon resaturation. A skillfully sealed borehole may be as impermeable as the host rock. Analysis of the influence of relative seal-rock permeabilities shows that a plug with permeability one order of magnitude greater than that of the rock results in a flow increase through the hole and surrounding rock of only 1-1/2 times compared to the undisturbed rock. Since a borehole is only a small part of the total rock mass, the total effect is even less pronounced. The simplest and most effective way to decrease flow through a rock-seal system is to increase the seal length, assuming it can be guaranteed that no dominant by-pass flowpath through the rock exists.

  15. Geotechnical properties of Karwar marine clay

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.T.; Nayak, B.U.; Naik, R.L.

    Karwar marine clay possesses high plasticity characteristics with natural water content higher than the liquid limit. Liquidity index was as high as 1.7. Predominant clay mineral was kaolinite. Undrained shear strength showed an increasing trend...

  16. Clay slurry and engineered soils as containment technologies for remediation of contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.R. [Reclamation Technology, Inc., Athens, GA (United States); Dudka, S.; Miller, W.P. [Univ. of Georgia, Athens, GA (United States); Johnson, D.O. [Argonne National Lab., IL (United States)

    1997-12-31

    Clay Slurry and Engineered Soils are containment technologies for remediation of waste disposal sites where leaching, groundwater plumes and surface runoff of contaminants are serious ecological hazards to adjacent environments. This technology is a patent-pending process which involves the use of conditioned clay materials mixed with sand and water to form a readily pourable suspension, a clay slurry, which is either placed into a trench barrier system or allowed to de-water to create Engineered Soils. The Engineered Soil forms a layer impervious to water and air, therefore by inhibiting both water and oxygen from penetrating through the soil the material. This material can be installed in layers and as a vertical barrier to create a surface barrier containment system. The clay percentage in the clay slurry and Engineered Soils varies depending on site characteristics and desired performance standards. For example Engineered Soils with 1-2% of clay (dry wt.) had a hydraulic conductivity (K) of 10{sup -8} to 10{sup -1} cm/sec. Tests of tailing materials from a kyanite and pyrite mine showed that the clay slurry was effective not only in reducing the permeability of the treated tailings, but also in decreasing their acidity due to the inherent alkalinity of the clay. The untreated tailings had pH values in the range of 2.4 - 3.1; whereas, the effluent from clay and tailings mixtures had pH values in a slightly alkaline range (7.7-7.9). Pug-mills and high volume slurry pumps can be readily adapted for use in constructing and placing caps and creating Engineered Soils. Moreover, material on site or from a local sand supply can be used to create clay slurries and engineered soils. Clay materials used in cap construction are likewise readily available commercially. As a result, the clay slurry system is very cost effective compared to other capping systems, including the commonly used High Density Polyethylene (HDPE) liner systems.

  17. Performance of polymeric films based thermoplastic starch and organophilic clay

    International Nuclear Information System (INIS)

    The aim of this work was the development and investigation of the properties of flat films of LDPE/corn thermoplastic starch (TPS). A bentonite clay (Argel) was organophilized and characterized by XRD. This clay (1%) in both pristine and organophilic forms was added to the matrix (LDPE) and to LDPE/TPS systems with TPS contents varying from 5-20% w/w. The films manufactured (LDPE, LDPE/Clay, LDPE/TPS, LDPE/TPS/Clay) were characterized. Results indicate that water vapor permeability is dependent and increases with TPS content which was attributed to the higher affinity of water by TPS. TPS and Clay addition to LDPE led to significant changes in film properties with respect to the neat LDPE. In general,tensile and perforation forces increased with clay and TPS contents; the strength of thermo sealed films lowered with natural clay addition and increased with TPS and organoclay incorporation and, in general, dynamic friction coefficient decrease with organoclay and TPS addition. Best overall properties were obtained for the systems containing the organoclay and optimal properties were achieved for the 5%TPS10 LDPE1% ANO system. (author)

  18. Clay Minerals: Adsorbophysical Properties

    International Nuclear Information System (INIS)

    The structure and features of surfaces of clay minerals (kaolin, montmorillonite, etc) have an important scientific and practical value. On the surface the interrelation of processes at electronic, atomic and molecular levels is realized. Availability of mineral surface to external influences opens wide scientific and technical opportunities of use of the surface phenomena, so the research of crystal-chemical and crystal-physical processes in near-surface area of clay minerals is important. After long term researches of gas-clay mineral system in physical fields the author has obtained experimental and theoretical material contributing to the creation of the surface theory of clays. A part of the researches is dedicated to studying the mechanism of crystal-chemical and crystal-physical processes in near surface area of clay mineral systems, selectivity of the surface centers to interact with gas phase molecules and adsorbophysical properties. The study of physical and chemical properties of fine clay minerals and their modification has a decisive importance for development of theory and practice of nanotechnologies: they are sorbents, membranes, ceramics and other materials with required electronic features

  19. Hydrogen solubility in pore water of partially saturated argillites: Application to Callovo-Oxfordian clay-rock in the context of a nuclear waste geological disposal

    International Nuclear Information System (INIS)

    In nuclear waste geological disposals, large amounts of hydrogen (H2) are expected to be produced by different (bio-)geochemical processes. Depending on the pressure generated by such a process, H2 could be produced as a gas phase and displace the neighbouring pore water. As a consequence, a water-unsaturated zone could be created around the waste and possibly affect the physical and physic-chemical properties of the disposal and the excavation disturbed zone around it. The present study is the first part of an ongoing research program aimed at evaluating the possible chemical evolution of the pore water-minerals-gas system in such a context. The goal of this study was to evaluate, in terms of thermodynamic equilibrium conditions, the geochemical disturbance of the pore water due to variations in hydrogen pressure, temperature and relative humidity. No heterogeneous reactions involving mineral phases of the clay-rock or reactive surface sites were taken into account in the thermodynamic analysis. In the case sulphate reduction reaction is allowed, geochemical modelling results indicate that the main disturbance is the increase in pH (from around 7 up to more than 10) and an important decrease in the redox potential (Eh) related to hydrogen dissolution. This occurs from relatively low H2 partial pressures (∼1 bar and above). Then, temperature and relative humidity (expressed in terms of capillary pressure) further displace the thermodynamic equilibrium conditions, namely the pH and the aqueous speciation as well as saturation indices of mineral phases. Finally, the results suggest that the generation of hydrogen, combined with an increase in temperature (between 30 deg. C and 80 deg. C) and a decrease in relative humidity (from 100% to 30%), should increase the chemical reactivity of the pore water-rock-gas system. (authors)

  20. Imaging beneath the skin of large tropical rivers: Clay controls on system morphodynamics revealed by novel CHIRP sub-surface sonar and deep coring along the Fly and Strickland Rivers, Papua New Guinea (Invited)

    Science.gov (United States)

    Aalto, R. E.; Grenfell, M.; Lauer, J. W.

    2010-12-01

    Tropical rivers dominate Earth’s fluvial fluxes for water, carbon, and mineral sediment. They are characterized by large channels and floodplains, old system histories (in comparison to many temperate rivers), frequent and prolonged periods of flooding, and a clay-dominated sediment flux transported above a sandy bed. However, limited insight is available regarding the underlying bed & floodplain strata -- material that underpins system mobility and morphodynamics. Available data commonly stems from “skin-deep” approaches such as GIS analysis of imagery, shallow sampling of a surface veneer, & topographic profiling during lower river stages. Given the large temporal & spatial scales of such systems, new approaches are needed to see below lag deposits on mobile sandy beds & deep into expansive floodbasins. Furthermore, such data are needed to test whether we can usefully interpret large tropical river morphology using direct analogies to observations from small temperate sytems. Systems responding to sea level rise, pending avulsions, or an increase/contrast in sediment load would provide especially valuable insight. We conducted a field campaign along the Fly and Strickland Rivers in Papua New Guinea (discharge ~ 5,400 CMS). Immediate results were obtained using a dual-frequency CHIRP sub-bottom profiler optimized for fluvial environments, with which we were able to image 10-20m below the river/lake bed. We were able to distinguish sandy deposits from harder clay and silt lenses and also collected bed grab samples to verify our sonar results. Deep borehole samples (5-15m), push cores, and cutbank profiles of material strength confirmed observations from the sonar profiling. We simultaneously collected side-scan sonar imagery plus DGPS water/bed elevations. Findings include: 1) The prevalence of hard clay beneath the bed at many locations along the Lower Fly and Strickland Rivers, retarding migration; 2) Unusual bed morphology along the lower Middle Fly River

  1. Deposition and survival of Escherichia coli O157:H7 on clay minerals in a parallel plate flow system.

    Science.gov (United States)

    Cai, Peng; Huang, Qiaoyun; Walker, Sharon L

    2013-02-19

    Understanding bacterial pathogens deposition and survival processes in the soil-groundwater system is crucial to protect public health from soilborne and waterborne diseases. However, mechanisms of bacterial pathogen-clay interactions are not well studied, particularly in dynamic systems. Also, little is known about the viability of bacterial pathogens when attached to clays. In this study, a parallel plate flow system was used to determine the deposition kinetics and survival of Escherichia coli O157:H7 on montmorillonite, kaolinite, and goethite over a wide range of ionic strengths (IS) (0.1-100 mM KCl). E. coli O157:H7 deposition on the positively charged goethite is greater than that on the negatively charged kaolinite and montmorillonite. Although the zeta potential of kaolinite was more negative than that of montmorillonite, kaolinite showed a greater deposition for E. coli O157:H7 than montmorillonite, which is attributed to the chemical heterogeneity of clay minerals. Overall, increasing IS resulted in an increase of E. coli O157:H7 deposition on montmorillonite and kaolinite, and a decrease on goethite. Interaction energy calculations suggest that E. coli O157:H7 deposition on clays was largely governed by DLVO (Derjaguin-Landau-Verwey-Overbeek) forces. The loss of bacterial membrane integrity was investigated as a function of time using the Live/Dead BacLight viability assay. During the examined period of 6 h, E. coli O157:H7 retained its viability in suspension and when attached to montmorillonite and kaolinite; however, interaction with the goethite was detrimental. The information obtained in this study is of fundamental significance for the understanding of the fate of bacterial pathogens in soil environments.

  2. Advances in interaction mechanism of water (gas) on clay minerals in China

    Institute of Scientific and Technical Information of China (English)

    He Manchao; Sun Xiaoming; Zhao Jian

    2014-01-01

    Dealing with large-scale deformations in soft-rock tunnels is a very important issue in soft-rock tunnel engineering. The mechanism of this large-scale deformation is closely related to the physical and chem-ical properties of soft rock, interaction between soft rock and water, and interaction between soft rock and gas contained in soft rock. In order to gain a better predictive understanding of the governing prin-ciples associated with this phenomenon, we used experimental and theoretical methods to study the effects of point defect on physical and chemical properties of soft rock and mechanism of interaction between water (gas) and soft rock. Firstly, we calculated the impurity formation energies and transition energy levels of defects by using the first-principle calculation, the results showed the microscopic mech-anism of defects substitution in kaolinite and effects of defects on the structure of kaolinite. Moreover, comparing the experimental and theoretical results, we found the mechanism of interaction between water and soft rock. The results show that water is one of the most important factors which can induce various kinds of geological disasters. At last, the interaction between soft rock and surrounding gas as CO2, CH4 and CO is disused, the influence of surrounding gas on soft rock should not be ignored.

  3. Clay membrane made of natural high plasticity clay

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1998-01-01

    Leachate containment in Denmark has through years been regulated by the DIF Recommendation for Sanitary Landfill Liners (DS/R 466). It states natural clay deposits may be used for membrane material provided the membrane and drainage system may contain at least 95% of all leachate created throughout...... ion transport as well as diffusion.Clay prospection for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island Lolland. The natural clay contains 60 to 75% smectite, dominantly as a sodium-type. The clay material...... successfully. At natural watercontent w = 40 to 45% it is possible to establish a homogeneous membrane with hydraulic conductivity k

  4. Mineral Acquisition from Clay by Budongo Forest Chimpanzees

    OpenAIRE

    Vernon Reynolds; Andrew W Lloyd; English, Christopher J.; Peter Lyons; Howard Dodd; Catherine Hobaiter; Nicholas Newton-Fisher; Caroline Mullins; Noemie Lamon; Anne Marijke Schel; Brittany Fallon

    2015-01-01

    Date of Acceptance: 06/07/2015 Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay ea...

  5. Stable silicon isotope signatures of marine pore waters - Biogenic opal dissolution versus authigenic clay mineral formation

    Science.gov (United States)

    Ehlert, Claudia; Doering, Kristin; Wallmann, Klaus; Scholz, Florian; Sommer, Stefan; Grasse, Patricia; Geilert, Sonja; Frank, Martin

    2016-10-01

    Dissolved silicon isotope compositions have been analysed for the first time in pore waters (δ30SiPW) of three short sediment cores from the Peruvian margin upwelling region with distinctly different biogenic opal content in order to investigate silicon isotope fractionation behaviour during early diagenetic turnover of biogenic opal in marine sediments. The δ30SiPW varies between +1.1‰ and +1.9‰ with the highest values occurring in the uppermost part close to the sediment-water interface. These values are of the same order or higher than the δ30Si of the biogenic opal extracted from the same sediments (+0.3‰ to +1.2‰) and of the overlying bottom waters (+1.1‰ to +1.5‰). Together with dissolved silicic acid concentrations well below biogenic opal saturation, our collective observations are consistent with the formation of authigenic alumino-silicates from the dissolving biogenic opal. Using a numerical transport-reaction model we find that approximately 24% of the dissolving biogenic opal is re-precipitated in the sediments in the form of these authigenic phases at a relatively low precipitation rate of 56 μmol Si cm-2 yr-1. The fractionation factor between the precipitates and the pore waters is estimated at -2.0‰. Dissolved and solid cation concentrations further indicate that off Peru, where biogenic opal concentrations in the sediments are high, the availability of reactive terrigenous material is the limiting factor for the formation of authigenic alumino-silicate phases.

  6. Rocks, Clays, Water, and Salts: Highly Durable, Infinitely Rechargeable, Eminently Controllable Thermal Batteries for Buildings

    Directory of Open Access Journals (Sweden)

    Alan W. Rempel

    2013-01-01

    Full Text Available Materials that store the energy of warm days, to return that heat during cool nights, have been fundamental to vernacular building since ancient times. Although building with thermally rechargeable materials became a niche pursuit with the advent of fossil fuel-based heating and cooling, energy and climate change concerns have sparked new enthusiasm for these substances of high heat capacity and moderate thermal conductivity: stone, adobe, rammed earth, brick, water, concrete, and more recently, phase-change materials. While broadly similar, these substances absorb and release heat in unique patterns characteristic of their mineralogies, densities, fluidities, emissivities, and latent heats of fusion. Current architectural practice, however, shows little awareness of these differences and the resulting potential to match materials to desired thermal performance. This investigation explores that potential, illustrating the correspondence between physical parameters and thermal storage-and-release patterns in direct-, indirect-, and isolated-gain passive solar configurations. Focusing on heating applications, results demonstrate the superiority of water walls for daytime warmth, the tunability of granite and concrete for evening warmth, and the exceptional ability of phase-change materials to sustain near-constant heat delivery throughout the night.

  7. Defining an exposure-response relationship for suspended kaolin clay particulates and aquatic organisms: work toward defining a water quality guideline for suspended solids.

    Science.gov (United States)

    Gordon, Andrew K; Palmer, Carolyn G

    2015-04-01

    Water quality guidelines for suspended solids generally rely on the percentage departure from reference condition, an approach that has been criticized. Attempts to develop a biological effects-base guideline have, however, been confounded by low data availability. Furthermore, the high biological response variability to suspended solids exposure suggests that organisms are responding not only to exposure concentration and duration but also to other mechanisms of effect associated with suspended particles (e.g., size, shape, and geochemical composition). An alternative option is to develop more situation and site specific guidelines by generating biological effects data to suspended particles of a particular geochemistry and restricted size range. With this in mind, aquatic organism responses to kaolin clay particle exposure were collated from the literature and incorporated into 2 exposure-response relationship approaches. The species sensitivity distribution approach produced a hazardous concentration affecting 5% of species estimate of 58 mg/L for mortality responses, and 36 mg/L for sublethal data. The severity-of-ill-effect approach produced similar estimates for lethal and sublethal data. These results suggest that aquatic organisms are slightly more tolerant of kaolin clay particles than particles from barite or bentonite clays, based on results from previous studies on these clay types. This type of information can enable better estimates of the risk faced by aquatic organisms exposed to suspended solids. For example, when the sediments of a particular water body are dominated by a particular type of clay particle, then the most appropriate exposure-response relationship can be applied.

  8. Viscous property of dried clay

    Institute of Scientific and Technical Information of China (English)

    XU Li-sheng; LI Jian-zhong

    2006-01-01

    One dimensional and triaxial compression tests of air-dried and oven-dried Fujinomori clay and Pisa clay were carried out. Water content is less than 4.5 % and 1.0% for air-dried and oven-dried clay specimens, respectively. In all tests, axial strain rate was changed stepwise many times and drained creep tests were performed several times during monotonic loading at a constant strain rate. Global unloading (and also reloading in some tests) was applied during which creep loading tests were performed several times. Cyclic loading with small stress amplitude and several cycles was also performed to calculate the modulus of elasticity of the clay in tests. Local displacement transducer was used in triaxial compression test to increase measuring accuracy of axial strain. The results show that air-dried and oven-dried clay have noticeable viscous properties; during global unloading, creep deformation changes from positive to negative, i.e. there exist neutral points (zero creep deformation or no creep deformation point) in global unloading part of strain-stress curve; viscous property of Fujinomori clay decreases when water content decreases, i.e. viscous property of air-dried Fujinomori clay is more significant than that of oven-dried Fujinomori clay.

  9. Study on adsorption of uranium(VI) on clay and its significance for control of ground water pollution

    International Nuclear Information System (INIS)

    The batch experiments for adsorption of uranium (VI) on clay collected from the bottom of a huge mill-tailing in southern China were conducted. The results show that the adsorption of uranium (VI) on clay is a obviously nonlinear function of pH in solution, leaching a maximum around neutral pH and decreasing rapidly towards more acidic or alkaline conditions. The diffuse layer model (DLM) which describes the adsorption of uranium (VI) on clay was established according to the surface complexation approach, and it simulates the experimental data successfully. The calibration displays that the model has strong capacity to predict uranium (VI) sorption behavior under different thermodynamic condition. The simulating results indicate that U(VI) adsorption on clay is affected by solid-liquid ratio (M/V) obviously at low pH and controlled by HCO3- and Co32- in solution at high pH

  10. DFT theoretical and FT-IR spectroscopic investigations of the plasticity of clay minerals dispersions

    Science.gov (United States)

    Kasprzhitskii, A.; Lazorenko, G.; Yavna, V.; Daniel, Ph.

    2016-04-01

    Plasticity is the most important property of dispersions of clay minerals that determine the character of participation of these systems in many natural and technological processes. We report on the results of studies of hydration mechanism in typical clay minerals making part of natural dispersions of sedimentation masses by means of IR spectroscopy and theoretical density functional theory (DFT) methods. X-ray diffraction analysis of clay minerals of Millerovo mineral deposit (Russian Federation) is carried out. Regularities and peculiarities of interaction of water molecules with kaolinite basal planes (001) and (00 1 bar) are analyzed. The role of water in the formation of plasticity of clay minerals dispersions is revealed. The modes of water molecules placement and their state and structure in the system "clay mineral-water" is defined. Phase transition processes of clay minerals dispersion into plastic and liquid state and their influence on spectral characteristics of the systems are investigated. The interpretation of clay minerals phase transitions into plastic and fluid state based on the results of DFT simulation is given. The relation is established between specific variation of spectral characteristics and phase transitions of clay minerals dispersions into plastic and liquid state.

  11. A Time Resolved XANES Study of an Organo-Clay Redox System

    OpenAIRE

    Gates, W.; Hunter, D.; Nuessle, P.; Bertsch, P.

    1997-01-01

    In situ, time-resolved X-ray absorption near edge structure (XANES) spectroscopic measurements of tetraphenylboron (TPB)-treated Fe-bearing clay minerals were conducted to investigate whether smectite structural Fe was reduced during surface-enhanced oxidative degradation of TPB. Reference samples were prepared by reducing varying amounts of structural Fe with Na-dithionite in an inert atmosphere. Analysis of the Kα X-ray fluorescence near edge structure of reference and TPB-treated samples w...

  12. In situ synthesis of nano clay filled polyethylene using polymer support metallocenes catalyst system

    International Nuclear Information System (INIS)

    In situ ethylene polymerizations were performed using bis(cyclopentadiene)titanium dichloride supported on poly ethersulfone as catalyst. The bis(cyclopentadiene)titanium dichloride supported on poly ethersulfone catalyst activity estimated by ethylene polymerization was 360 kg PE/mol Ti/h. During polymerization the fillers used were montmorillonite nano clays having surface modifications with 35-45 wt % dimethyl dialkyl(14-18)amine (FA) and 25-30 wt % trimethyl stearyl ammonium (FB). These fillers were pretreated with methylaluminoxine (MAO; co catalyst) for better dispersion onto the polymer matrix. The formation of polyethylene within the whole matrix was confirmed by FTIR studies. It was found that the nature of nano filler did not have any remarkable effect on the melting characteristics of the polymer. TGA study indicates that nano clay FB filled polyethylene has higher thermal stability than nano clay FA filled polyethylene. The melting temperature of the obtained polyethylenes was 142 degree C, which corresponds to that synthesized by the polyether sulfone supported catalyst. (author)

  13. Novel Anionic Clay Adsorbents for Boiler-Blow-Down Waters Reclaim and Reuse

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad Sahimi; Theodore Tsotsis

    2010-01-08

    Arsenic (As) and Selenium (Se) are found in water in the form of oxyanions. Relatively high concentrations of As and Se have been reported both in power plant discharges, as well as, in fresh water supplies. The International Agency for Research on Cancer currently classifies As as a group 1 chemical, that is considered to be carcinogenic to humans. In Phase I of this project we studied the adsorption of As and Se by uncalcined and calcined layered double hydroxide (LDH). The focus of the present work is a systematic study of the adsorption of As and Se by conditioned LDH adsorbents. Conditioning the adsorbent significantly reduced the Mg and Al dissolution observed with uncalcined and calcined LDH. The adsorption rates and isotherms have been investigated in batch experiments using particles of four different particle size ranges. As(V) adsorption is shown to follow a Sips-type adsorption isotherm. The As(V) adsorption rate on conditioned LDH increases with decreasing adsorbent particle size; the adsorption capacity, on the other hand, is independent of the particle size. A homogeneous surface diffusion model (HSDM) and a bi-disperse pore model (BPM) - the latter viewing the LDH particles as assemblages of microparticles and taking into account bulk diffusion in the intraparticle pore space, and surface diffusion within the microparticles themselves - were used to fit the experimental kinetic data. The HSDM estimated diffusivity values dependent on the particle size, whereas the BPM predicted an intracrystalline diffusivity, which is fairly invariant with particle size. The removal of As(V) on conditioned LDH adsorbents was also investigated in flow columns, where the impact of important solution and operational parameters such as influent As concentration, pH, sorbent particle size and flow rate were studied. An early breakthrough and saturation was observed at higher flow rates and at higher influent concentrations, whereas a decrease in the sorbent particle

  14. 1st International Conference on Calcined Clays for Sustainable Concrete

    CERN Document Server

    Favier, Aurélie

    2015-01-01

    This volume focuses on research and practical issues linked to Calcined Clays for Sustainable Concrete. The main subjects are geology of clays, hydration and performance of blended systems with calcined clays, alkali activated binders, economic and environmental impacts of the use of calcined clays in cement based materials. Topics addressed in this book include the influence of processing on reactivity of calcined clays, influence of clay mineralogy on reactivity, geology of clay deposits, Portland-calcined clay systems, hydration, durability, performance, Portland-calcined clay-limestone systems, hydration, durability, performance, calcined clay-alkali systems, life cycle analysis, economics and environmental impact of use of calcined clays in cement and concrete, and field applications. This book compiles the different contributions of the 1st International Conference on Calcined Clays for Sustainable Concrete, which took place in Lausanne, Switzerland, June, 23-25, 2015.The papers present the latest  res...

  15. Proceedings of the NEA Clay Club Workshop on Clay characterisation from nanoscopic to microscopic resolution

    International Nuclear Information System (INIS)

    A wide spectrum of argillaceous media are being considered in Nuclear Energy Agency (NEA) member countries as potential host rocks for the final, safe disposal of radioactive waste, and/or as major constituent of repository systems in which wastes will be emplaced. In this context, the NEA established the Working Group on the 'Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations' in 1990, informally known as the 'Clay Club'. The Clay Club examines various argillaceous rocks that are being considered for the underground disposal of radioactive waste, ranging from soft clays to indurated shales. Very generally speaking, these clay rocks are composed of fine-grained minerals showing pore sizes from < 2 nm (micropores) up to > 50 nm (macro-pores). The water flow, solute transport and mechanical properties are largely determined by this microstructure, the spatial arrangement of the minerals and the chemical pore water composition. Examples include anion accessible ('geochemical') porosity and macroscopic membrane effects (chemical osmosis, hyper-filtration), geomechanical properties and the characteristics of two-phase flow properties (relevant for gas transport). At the current level of knowledge, there is a strong need to improve the nanoscale description of the phenomena observed at a more macroscopic scale. However, based on the scale of individual clay-minerals and pore sizes, for most of the imaging techniques this resolution is a clear challenge. The workshop, hosted by the Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT) in the Akademiehotel Karlsruhe (Germany) from 6 to 8 September 2011, was intended to give, inter alia, a discussion platform on: - The current state-of-the-art of different spectro-microscopic methods - New developments addressing the above mentioned knowledge gaps in clays. - The perception of the interplay between geometry

  16. Monitoring instream turbidity to estimate continuous suspended-sediment loads and yields and clay-water volumes in the upper North Santiam River Basin, Oregon, 1998-2000

    Science.gov (United States)

    Uhrich, Mark A.; Bragg, Heather M.

    2003-01-01

    Three real-time, instream water-quality and turbidity-monitoring sites were established in October 1998 in the upper North Santiam River Basin on the North Santiam River, the Breitenbush River, and Blowout Creek, the main tributary inputs to Detroit Lake, a large, controlled reservoir that extends from river mile 61 to 70. Suspended-sediment samples were collected biweekly to monthly at each station. Rating curves provided estimated suspended-sediment concentration in 30-minute increments from log transformations of the instream turbidity monitoring data. Turbidity was found to be a better surrogate than discharge for estimating suspended-sediment concentration. Daily and annual mean suspended-sediment loads were estimated using the estimated suspended-sediment concentrations and corresponding streamflow data. A laboratory method for estimating persistent (residual) turbidity from separate turbidity samples was developed. Turbidity was measured over time for each sample. Turbidity decay curves were derived as the suspended sediment settled. Each curve was used to estimate a turbidity value for a given settling time. Medium to fine clay particle (size clay particle persistent turbidity for each site. The monitored instream 30-minute turbidity values were converted to a calculated persistent turbidity value that would have resulted after 8.5 hours of settling in the laboratory. Persistent turbidities of 10 NTU and above were tabulated for each site. (Water of 10 NTU and above can interfere with or damage treatment filters and result in intake closures at drinking-water facilities.) A method was developed that used the persistent turbidity experiments, turbidity decay curves, and stream discharge to estimate the volume of water containing suspended clay that entered Detroit Lake from the three main tributaries. 'Suspended-clay water' was defined as water having a value of at least 10 NTU after settling the required 8.5 hours. The suspended-clay concentrations of 10

  17. Stiff clay masses: big storages of fossil and renewable energy

    Science.gov (United States)

    Spilotro, Giuseppe; Fidelibus, Maria Dolores; Qeraxhiu, Lydra; Argentiero, Ilenia; Pellicani, Roberta

    2016-04-01

    The crystalline structure of the clay and its behaviour at the micro and macro scale have been and are still the object of studies in different fields of earth science: mineralogy, geotechnics, etc. It has been known for several decades that the volumetric equilibrium of a well-defined clay (mono mineralogical or mineralogical melange, with or without the mixing with other fines), depends on the salinity of the interstitial fluid (in terms of concentration of one or more kind of salts) under a stress field. The mechanism is very complex involving many chemical and physical topics, but may be easy to understand: the elementary structures of a two faced crystals are electrically negative charged with the interstitial fluid as the dielectric of a capacitor. Consequently, an electrical field is generated whose intensity depends on the electric charge and the properties of the dielectric. Such electric field can produce mechanical work, enlarging the faces of the capacitor, unless external forces prevent it. If external forces exceed the internal ones, the system behaves as a loaded spring, which stores energy of deformation to give back as soon as the external force weakens. The clay of marine sedimentation incorporates interstitial salt water of composition derived and similar to those of sea water. Such type of interstitial water chemically has high concentration of dissolved ions, mainly Na, which generates in the dielectric spaces a low electrical field, compared with that given in identical situation by low salt concentration in interstitial water. In nature, as well described in geoscience, the turning between the two interstitial water types is very common and driven by ion diffusion processes like, surface fresh water interacting with salt interstitial water of old marine clays. The latter, either by the overburden of younger sedimentary layers, but mainly by very strong capillary forces activated by surface drainage and EVT from sun and dry wind, undergo

  18. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    T.M. Whitworth; Liangxiong Li

    2002-09-15

    This report describes work performed during the first year of the project ''Modified Reverse Osmosis System for Treatment of Produced Waters.'' This research project has two objectives. The first objective is to test the use of clay membranes in the treatment of produced waters by reverse osmosis. The second objective is to test the ability of a system patented by the New Mexico Tech Research Foundation to remove salts from reverse osmosis waste streams as a solid. We performed 12 experiments using clay membranes in cross-flow experimental cells. We found that, due to dispersion in the porous frit used adjacent to the membrane, the concentration polarization layer seems to be completely (or nearly completely) destroyed at low flow rates. This observation suggests that clay membranes used with porous frit material many reach optimum rejection rates at lower pumping rates than required for use with synthetic membranes. The solute rejection efficiency decreases with increasing solution concentration. For the membranes and experiments reported here, the rejection efficiency ranged from 71% with 0.01 M NaCl solution down to 12% with 2.3 M NaCl solution. More compacted clay membranes will have higher rejection capabilities. The clay membranes used in our experiments were relatively thick (approximately 0.5 mm). The active layer of most synthetic membranes is only 0.04 {micro}m (0.00004 mm), approximately 1250 times thinner than the clay membranes used in these experiments. Yet clay membranes as thin as 12 {micro}m have been constructed (Fritz and Eady, 1985). Since Darcy's law states that the flow through a material of constant permeability is inversely proportional to it's the material's thickness, then, based on these experimental observations, a very thin clay membrane would be expected to have much higher flow rates than the ones used in these experiments. Future experiments will focus on testing very thin clay membranes. The

  19. Thermomechanical model of hydration swelling in smectitic clays: I two-scale mixture-theory approach

    Science.gov (United States)

    Murad, Márcio A.

    1999-06-01

    A thermomechanical theory of hydration swelling in smectitic clays is proposed. The clay is treated as a three-scale swelling system wherein macroscopic governing equations are derived by upscaling the microstructure. At the microscale the model has two phases, the disjoint clay platelets and adsorbed water (water between the platelets). At the intermediate (meso) scale (the homogenized microscale) the model consists of clay particles (adsorbed water plus clay platelets) and bulk water. At the macroscale the medium is treated as an homogenized swelling mixture of clay particles and bulk-phase water with thermodynamic properties defined everywhere within the macroscopic body. In Part I, the mesoscopic model governing the swelling of the clay particles is derived using a mixture-theoretic approach and the Coleman and Noll method of exploitation of the entropy inequality. Application of this procedure leads to two-scale governing equations which generalize the classical thermoelastic consolidation model of non-swelling media, as they exhibit additional physico-chemical and viscous-type terms accounting for hydration stresses between the adsorbed fluid and the clay minerals. In Part II the two-scale model is applied to a bentonitic clay used for engineered barrier of nuclear waste repository. The clay buffer is assumed to have monomodal character with most of the water essentially adsorbed. Further, partial results toward a three-scale thermomechanical macroscopic model including the bulk phase next to the swelling particles are derived by homogenizing the two-scale model with the bulk water. A notable consequence of this three-scale approach is that it provides a rational basis for the appearance of a generalized inter-phase mass transfer between adsorbed and bulk water.

  20. Physicochemical and Analytical Data for Tributary Water, Lake Water, and Lake Sediment, Lake Arrowhead, Clay and Archer Counties, Texas, 2006

    Science.gov (United States)

    Wilson, Jennifer T.; Musgrove, MaryLynn; Haynie, Monti M.; Van Metre, Peter C.

    2008-01-01

    Lake Arrowhead is a reservoir about 24 kilometers southeast of Wichita Falls, Texas, that provides drinking water for the city of Wichita Falls and surrounding areas. The U.S. Geological Survey, in cooperation with the City of Wichita Falls, did a study in 2006 to assess conditions contributing to elevated arsenic concentrations in Lake Arrowhead. This report describes the sampling and analytical methods, quality assurance, and physicochemical and analytical data. Physiochemical properties were measured in and water samples were collected from five tributaries to Lake Arrowhead (Little Wichita River, West Little Post Oak Creek, East Little Post Oak Creek, Deer Creek, and an unnamed tributary) immediately after storms. Lake water measuring and sampling were done approximately monthly from January through September 2006 at three deep-water sites and seasonally, in January and August 2006, at three shallow-water sites. Cores of lake bottom sediment were collected from five sites on August 30, 2006. Arsenic concentrations in tributary water samples ranged from 1.5 to 6.3 and 0.5 to 4.8 micrograms per liter for unfiltered and filtered samples, respectively. The highest arsenic concentrations were in samples collected from the West Little Post Oak Creek sampling site. Physicochemical properties in lake water varied with depth and season. Dissolved arsenite plus arsenate concentrations in lake water samples generally were between 3 and 5 micrograms per liter. Arsenite concentrations typically were below the laboratory reporting level of 0.6 microgram per liter. There were no detections of monomethylarsonate or dimethylarsinate. The concentration of arsenic in lake sediment samples ranged from 4.4 to 11.2 milligrams per kilogram, with a median of 6.4 milligrams per kilogram. The median arsenic concentration of the five top-interval sediment samples was 8.8 milligrams per kilogram, which generally is higher than the concentrations estimated to be on suspended sediment in

  1. Effect of clay organic modifier on the final performance of PCL/clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Luduena, L.N., E-mail: luduena@fi.mdp.edu.ar [Research Institute of Material Science and Technology (INTEMA), Engineering Faculty, National University of Mar del Plata, Juan B. Justo 4302 B7608FDQ, Mar del Plata (Argentina); Kenny, J.M. [Institute of Polymers Science and Technology, ICTP, Juan de la Cierva 3, 28006 Madrid (Spain); Vazquez, A., E-mail: avazquez@fi.uba.ar [INTECIN (UBA-CONICET), Polymer and Composite Group, Engineering Faculty, University of Buenos Aires, Las Heras 2214 C1063ACV, Buenos Aires (Argentina); Alvarez, V.A., E-mail: alvarezvera@fi.mdp.edu.ar [Research Institute of Material Science and Technology (INTEMA), Engineering Faculty, National University of Mar del Plata, Juan B. Justo 4302 B7608FDQ, Mar del Plata (Argentina)

    2011-11-25

    Highlights: {yields} The degradation of clay organo-modifiers during processing affect clay dispersion degree and clay content inside the matrix. {yields} Isothermal thermogravimetrical analysis was used to simulate the thermal degradation of clay organo-modifiers in extrusion. {yields} Improving polymer-clay compatibility may not be the main factor to achieve the best mechanical performance. {yields} The best combination between PCL/clay compatibility and thermal resistance of the clay, was obtained for C20A. - Abstract: The effect of un-modified and several organo-modified montmorillonites on the morphology, mechanical properties and thermal behavior of polycaprolactone (PCL) based nanocomposites prepared by melt intercalation was studied. The study was centered on the analysis of the clay characteristics that have influence on the final properties of PCL/clay nanocomposites. Polymer/clay compatibility was analyzed studying both bulk and surface polarity degree of the clays by means of water absorption tests (bulk) and contact angle measurements (surface). The thermal stability of the clays was analyzed by dynamic thermogravimetrical tests (TGA). The degradation of the clay organo-modifiers during processing was simulated by isothermal TGA. The clay dispersion degree inside the nanocomposites was analyzed by X-ray diffractometry (XRD). The melt rheology was used as a method to compare the dispersion degree of the clay by means of the shear thinning exponent, n{sub Rh}. The tensile mechanical properties were measured and theoretically analyzed by means of several micro-mechanical models. It was found that the thermal stability of the clay organo-modifiers is a critical factor that can modify the final clay content and the clay dispersion degree inside the nanocomposite, demonstrating that the enhancement of the polymer-clay compatibility may not be the main factor to achieve the best mechanical performance when shear forces during processing, i.e. extrusion

  2. Novel system for reducing leaching of the herbicide metribuzin using clay-gel-based formulations

    OpenAIRE

    Maqueda Porras, Celia; Villaverde Capellán, J.; Sopeña Vázquez, F.; Undabeytia López, Tomás; Morillo González, Esmeralda

    2008-01-01

    Metribuzin is an herbicide widely used for weed control that has been identified as a groundwater pollutant. It contaminates the environment even when it is used according to the manufacturer's instructions. To reduce herbicide leaching and increase weed control, new controlled release formulations were developed by entrapping metribuzin within a sepiolite-gel-based matrix using two clay/herbicide proportions (0.5/0.2 and 1/0.2) (loaded at 28.6 and 16.7% a.i.) as a gel (G28, G16) or as a powd...

  3. Carbon sequestration in clay and silt fractions of Brazilian soils under conventional and no-tillage systems

    Directory of Open Access Journals (Sweden)

    Cecília Estima Sacramento dos Reis

    2014-08-01

    Full Text Available The capacity of soils to sequestrate carbon (C is mainly related to the formation of organo-mineral complexes. In this study, we investigated the influence of soil management systems on the C retention capacity of soil with an emphasis on the silt and clay fractions of two subtropical soils with different mineralogy and climate. Samples from a Humic Hapludox and a Rhodic Hapludox, clayey soils cultivated for approximately 30 years under no-tillage (NT and conventional tillage (CT were collected from six layers distributed within 100-cm soil depth from each site and from an adjacent native forest. After the removal of particulate organic matter (POM, the suspension (<53 µm was sonicated, the silt and clay fractions were separated in accordance with Stokes' law and the carbon content of whole soil and physical fractions was determined. In the Humic Hapludox, the clay and silt fractions under NT showed a higher maximum C retention (72 and 52 g kg-1, respectively in comparison to those under CT (54 and 38 g kg-1, respectively. Moreover, the C concentration increase in both fractions under NT occurred mainly in the topsoil (up to 5 cm. The C retention in physical fractions of Rhodic Hapludox varied from 25 to 32 g kg-1, and no difference was observed whether under an NT or a CT management system. The predominance of goethite and gibbsite in the Humic Hapludox, as well as its exposure to a colder climate, may have contributed to its greater C retention capacity. In addition to the organo-mineral interaction, a mechanism of organic matter self-assemblage, enhanced by longer periods of soil non-disturbance, seems to have contributed to the carbon stabilization in both soils.

  4. Hydro-mechanical coupling and permeability of an unsaturated swelling clay under hydrous and thermal stress: sorption curve and water permeability

    International Nuclear Information System (INIS)

    The use of swelling clay for engineered safety barriers of radioactive waste disposal require the understanding of its thermal-hydro-mechanical behaviour. This work concerns particularly the characterization and the modelling of the behaviour of one of these clays: the FoCa7 clay. The characteristics of the studied material are: the sorption (desorption) curve and the water permeability. For each of them, new experiments have allowed to acquire data in fields still few explored: in temperature (between 20 and 80 C) for the sorption curve and in the unsaturated field for the water permeability. The analysis of these results and of bibliographic data has allowed in one hand to estimate the importance of the hysteresis phenomenon and the temperature influence on the sorption curve and in another hand, to establish the requirement to introduce in the modelling of the sorption curve, a plastic parameter due to the irreversible deformations occurring during the compaction. Moreover, the tests carried out for data acquirement have been used too to give validation elements to the non linear behaviour laws proposed by O. Coussy and P. Dangla for the non saturated porous media. The particularity of these laws is to suppose the existence of an effective constraint in the non saturated field, this shows the importance of the validation elements presented here. (O.M.)

  5. Contact micromechanics in granular media with clay

    Energy Technology Data Exchange (ETDEWEB)

    Ita, S.L.

    1994-08-01

    Many granular materials, including sedimentary rocks and soils, contain clay particles in the pores, grain contacts, or matrix. The amount and location of the clays and fluids can influence the mechanical and hydraulic properties of the granular material. This research investigated the mechanical effects of clay at grain-to-grain contacts in the presence of different fluids. Laboratory seismic wave propagation tests were conducted at ultrasonic frequencies using spherical glass beads coated with Montmorillonite clay (SWy-1) onto which different fluids were adsorbed. For all bead samples, seismic velocity increased and attenuation decreased as the contact stiffnesses increased with increasing stress demonstrating that grain contacts control seismic transmission in poorly consolidated and unconsolidated granular material. Coating the beads with clay added stiffness and introduced viscosity to the mechanical contact properties that increased the velocity and attenuation of the propagating seismic wave. Clay-fluid interactions were studied by allowing the clay coating to absorb water, ethyl alcohol, and hexadecane. Increasing water amounts initially increased seismic attenuation due to clay swelling at the contacts. Attenuation decreased for higher water amounts where the clay exceeded the plastic limit and was forced from the contact areas into the surrounding open pore space during sample consolidation. This work investigates how clay located at grain contacts affects the micromechanical, particularly seismic, behavior of granular materials. The need for this work is shown by a review of the effects of clays on seismic wave propagation, laboratory measurements of attenuation in granular media, and proposed mechanisms for attenuation in granular media.

  6. Biogeochemical processes in a clay formation in situ experiment: Part A - Overview, experimental design and water data of an experiment in the Opalinus Clay at the Mont Terri Underground Research Laboratory, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Wersin, P., E-mail: paul.wersin@gruner.ch [NAGRA, Hardstrasse 73, 5430 Wettingen (Switzerland)] [Gruner Ltd., Gellertstrasse 55, 4020 Basel (Switzerland); Leupin, O.X. [NAGRA, Hardstrasse 73, 5430 Wettingen (Switzerland); Mettler, S. [NAGRA, Hardstrasse 73, 5430 Wettingen (Switzerland)] [Solexperts Ltd., Mettlenbachstrasse 25, 8617 Moenchaltorf (Switzerland); Gaucher, E.C. [BRGM, 3 avenue Claude Guillemin, B.P. 36009, 45060 Orleans Cedex 2 (France); Maeder, U. [University of Bern, Institute of Geological Sciences, Baltzerstrasse 3, CH-3012 Bern (Switzerland); De Canniere, P. [SCK.CEN, Waste and Disposal Project, Boeretang 200, 2400 Mol (Belgium); Vinsot, A. [ANDRA, Laboratoire de Recherche Souterrain de Meuse/Haute-Marne, RD960 BP9, 55290 Bure (France); Gaebler, H.E. [BGR, Stilleweg 2, 30655 Hannover (Germany); Kunimaro, T. [JAEA, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kiho, K. [CRIEPI, 1646 Abiko, Abiko-city Chiba 270-1194 (Japan); Eichinger, L. [Hydroisotop, 85301 Schweitenkirchen (Germany)

    2011-06-15

    Highlights: > The composition was affected by the complex interplay of diffusion, mineral and surface reactions. > The {sup 13}C signals for carbon species showed significant variations which could only be partly explained. > The main cations remained remarkably constant during the experiment. > This underlines the strong buffering via cation exchange and carbonate dissolution/precipitation. - Abstract: An in situ test in the Opalinus Clay formation, termed porewater chemistry (PC) experiment, was carried out for a period of 5 years. It was based on the concept of diffusive equilibration whereby a traced water with a composition close to that expected in the formation was continuously circulated and monitored in a packed-off borehole. The main original focus was to obtain reliable data on the pH/pCO{sub 2} conditions of the porewater, but because of unexpected microbiologically-induced redox reactions, the objective was extended to elucidate the biogeochemical processes occurring in the borehole and to understand their impact on pH/pCO{sub 2} and porewater chemistry in the low permeability clay formation. The behaviour of the conservative tracers {sup 2}H and Br{sup -} could be explained by diffusive dilution in the clay and moreover the results showed that diffusive equilibration between the borehole water and the formation occurred within about 3 year's time. However, the composition and pH/pCO{sub 2} conditions differed considerably from those of the in situ porewater. Thus, pH was lower and pCO{sub 2} was higher than indicated by complementary laboratory investigations. The noted differences are explained by microbiologically-induced redox reactions occurring in the borehole and in the interfacial wall area which were caused by an organic source released from the equipment material. The degradation of this source was accompanied by sulfate reduction and - to a lesser extent - by methane generation, which induced a high rate of acetogenic reactions

  7. Effects of clay dispersion on aquifer storage and recovery in coastal aquifers

    Science.gov (United States)

    Konikow, L.F.; August, L.L.; Voss, C.I.

    2001-01-01

    Cyclic injection, storage, and withdrawal of freshwater in brackish aquifers is a form of aquifer storage and recovery (ASR) that can beneficially supplement water supplies in coastal areas. A 1970s field experiment in Norfolk, Virginia, showed that clay dispersion in the unconsolidated sedimentary aquifer occurred because of cation exchange on clay minerals as freshwater displaced brackish formation water. Migration of interstitial clay particles clogged pores, reduced permeability, and decreased recovery efficiency, but a calcium preflush was found to reduce clay dispersion and lead to a higher recovery efficiency. Column experiments were performed in this study to quantify the relations between permeability changes and clay mineralogy, clay content, and initial water salinity. The results of these experiments indicate that dispersion of montmorillonite clay is a primary contributor to formation damage. The reduction in permeability by clay dispersion may be expressed as a linear function of chloride content. Incorporating these simple functions into a radial, cross-sectional, variable-density, ground-water flow and transport model yielded a satisfactory simulation of the Norfolk field test - and represented an improvement over the model that ignored changes in permeability. This type of model offers a useful planning and design tool for ASR operations in coastal clastic aquifer systems.

  8. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    T.M. Whitworth; Liangxiong Li

    2002-09-15

    This report describes work performed during the second year of the project ''Modified reverse osmosis system for treatment of produced waters.'' We performed two series of reverse osmosis experiments using very thin bentonite clay membranes compacted to differing degrees. The first series of 10 experiments used NaCl solutions with membranes that ranged between 0.041 and 0.064mm in thickness. Our results showed compaction of such ultra-thin clay membranes to be problematic. The thickness of the membranes was exceeded by the dimensional variation in the machined experimental cell and this is believed to have resulted in local bypassing of the membrane with a resultant decrease in solute rejection efficiency. In two of the experiments, permeate flow was varied as a percentage of the total flow to investigate results of changing permeate flow on solute rejection. In one experiment, the permeate flow was varied between 2.4 and 10.3% of the total flow with no change in solute rejection. In another experiment, the permeate flow was varied between 24.6 and 52.5% of the total flow. In this experiment, the solute rejection rate decreased as the permeate occupied greater fractions of the total flow. This suggests a maximum solute rejection efficiency for these clay membranes for a permeate flow of between 10.3 and 24.6% of the total; flow. Solute rejection was found to decrease with increasing salt concentration and ranged between 62.9% and 19.7% for chloride and between 61.5 and 16.8% for sodium. Due to problems with the compaction procedure and potential membrane bypassing, these rejection rates are probably not the upper limit for NaCl rejection by bentonite membranes. The second series of four reverse osmosis experiments was conducted with a 0.057mm-thick bentonite membrane and dilutions of a produced water sample with an original TDS of 196,250 mg/l obtained from a facility near Loco Hill, New Mexico, operated by an independent. These experiments

  9. Evaluation of Turf-Grass and Prairie-Vegetated Rain Gardens in a Clay and Sand Soil, Madison, Wisconsin, Water Years 2004-08

    Science.gov (United States)

    Selbig, William R.; Balster, Nicholas

    2010-01-01

    The U.S. Geological Survey, in cooperation with a consortium of 19 cities, towns, and villages in Dane County, Wis., undertook a study to compare the capability of rain gardens with different vegetative species and soil types to infiltrate stormwater runoff from the roof of an adjacent structure. Two rain gardens, one planted with turf grass and the other with native prairie species, were constructed side-by-side in 2003 at two locations with different dominant soil types, either sand or clay. Each rain garden was sized to a ratio of approximately 5:1 contributing area to receiving area and to a depth of 0.5 foot. Each rain garden, regardless of vegetation or soil type, was capable of storing and infiltrating most of the runoff over the 5-year study period. Both rain gardens in sand, as well as the prairie rain garden in clay, retained and infiltrated 100 percent of all precipitation and snowmelt events during water years 2004-07. The turf rain garden in clay occasionally had runoff exceed its confining boundaries, but was still able to retain 96 percent of all precipitation and snowmelt events during the same time period. Precipitation intensity and number of antecedent dry days were important variables that influenced when the storage capacity of underlying soils would become saturated, which resulted in pooled water in the rain gardens. Because the rooftop area that drained runoff to each rain garden was approximately five times larger than the area of the rain garden itself, evapotranspiration was a small percentage of the annual water budget. For example, during water year 2005, the maximum evapotranspiration of total influent volume ranged from 21 percent for the turf rain garden in clay to 25 percent for the turf rain garden in sand, and the minimum ranged from 12 percent for the prairie rain garden in clay to 19 percent for the prairie rain garden in sand. Little to no runoff left each rain garden as effluent and a small percentage of runoff returned to the

  10. 黏土渗透性能测试系统设计%Design of Permeability Testing System for Clay

    Institute of Scientific and Technical Information of China (English)

    杨世凤; 唐培成

    2011-01-01

    基于LabVIEW虚拟仪器技术开发平台,构建了黏土渗透性能测试系统.该系统由压力传感器、单片机、串口通信和计算机组成,采用LabVIEW编程实现数据实时采集与分析、历史数据的储存与查询等系统功能.将压力数据转换为液位数据,通过计算得到黏土的渗透系数.实验表明,该系统稳定可靠,可为工程建设提供有效数据参考.%Based on the platform of Lab VIEW virtual instrument technology, the clay permeability testing system was constructed. It was composed of pressure sensors, microcontroller, serial communication, and computers. By Lab VIEW technology.it achieved the functions of Real-time data collection and analysis, historical data storage and query. It changes pressure data into Level data, and achieves permeability coefficient of clay by the formula. Results show that the system is reliable and can provide effective data for project construction.

  11. Gardening in Clay Soils

    OpenAIRE

    Wagner, Katie; Kuhns, Michael; Cardon, Grant

    2015-01-01

    This fact sheet covers the basics of clay, silt and sand soils with an emphasis on gardening in soils with a high clay content. It includes information on the composition of clay soils, gardening tips for managing clay soils, and the types of plants that grow best in clay soils.

  12. Chemical and mineralogical characteristics of French green clays used for healing

    Science.gov (United States)

    Williams, L.B.; Haydel, S.E.; Giese, R.F.; Eberl, D.D.

    2008-01-01

    The worldwide emergence of infectious diseases, together with the increasing incidence of antibiotic-resistant bacteria, elevate the need to properly detect, prevent, and effectively treat these infections. The overuse and misuse of common antibiotics in recent decades stimulates the need to identify new inhibitory agents. Therefore, natural products like clays, that display antibacterial properties, are of particular interest. The absorptive properties of clay minerals are well documented for healing skin and gastrointestinal ailments. However, the antibacterial properties of clays have received less scientific attention. French green clays have recently been shown to heal Buruli ulcer, a necrotic or 'flesh-eating' infection caused by Mycobacterium ulcerans. Assessing the antibacterial properties of these clays could provide an inexpensive treatment for Buruli ulcer and other skin infections. Antimicrobial testing of the two clays on a broad-spectrum of bacterial pathogens showed that one clay promotes bacterial growth (possibly provoking a response from the natural immune system), while another kills bacteria or significantly inhibits bacterial growth. This paper compares the mineralogy and chemical composition of the two French green clays used in the treatment of Buruli ulcer. Mineralogically, the two clays are dominated by 1Md illite and Fe-smectite. Comparing the chemistry of the clay minerals and exchangeable ions, we conclude that the chemistry of the clay, and the surface properties that affect pH and oxidation state, control the chemistry of the water used to moisten the clay poultices and contribute the critical antibacterial agent(s) that ultimately debilitate the bacteria. Copyright ?? 2008, The Clay Minerals Society.

  13. Organic Control of Dioctahedral and Trioctahedral Clay Formation in an Alkaline Soil System in the Pantanal Wetland of Nhecolândia, Brazil

    Science.gov (United States)

    Meunier, Jean-François; Martins-Silva, Elisângela R.; Furian, Sonia

    2016-01-01

    Recent studies have focused on the formation of authigenic clays in an alkaline soil system surrounding lakes of the Nhecolândia region, Pantanal wetland. The presence of trioctahedral Mg-smectites (stevensite and saponite types), which requires low Al and Fe contents in the soil solution for its formation, contrasts with the neoformation of dioctahedral Fe-mica (glauconite, and Fe-illite), which instead requires solutions relatively enriched in Al and Fe. This study aims to understand the conditions of co-existence of both, Mg-smectite and Fe-mica a common clay association in former or modern alkaline soil systems and sediments. The study was carried out along an alkaline soil catena representative of the region. The soil organization revealed that Mg-smectite occur in top soil close to the lake, whereas Fe-mica dominate in the clay fraction of deeper greenish horizons a few meters apart. We propose here that this spatial distribution is controlled by the lateral transfer of Fe and Al with organic ligands. Alkaline organic rich solutions (DOC up to 738 mg L-1) collected in the watertable were centrifuged and filtered through membranes of decreasing pore size (0.45 μm, 0.2 μm, 30 KDa, 10 KDa, 3 KDa) to separate colloidal and dissolved fractions. Fe, Al, Si, Mg and K were analysed for each fraction. Although the filtration had no influence on Si and K contents, almost 90% of Fe (up to 2.3 mg L-1) and Al (up to 7 mg L-1) are retained at the first cutoff threshold of 0.45μm. The treatment of the same solutions by oxygen peroxide before filtration shows that a large proportion of Fe and Al were bonded to organic colloids in alkaline soil solution at the immediate lake border, allowing Mg-smectite precipitation. The fast mineralization of the organic matter a few meters apart from the lake favors the release of Fe and Al necessary for Fe-mica neoformation. In comparison with chemical and mineralogical characteristics of alkaline environments described in the

  14. Public Water Supply Systems (PWS)

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset includes boundaries for most public water supply systems (PWS) in Kansas (525 municipalities, 289 rural water districts and 13 public wholesale water...

  15. Cotransport of clay colloids and viruses through water-saturated vertically oriented columns packed with glass beads: Gravity effects.

    Science.gov (United States)

    Syngouna, Vasiliki I; Chrysikopoulos, Constantinos V

    2016-03-01

    The cotransport of clay colloids and viruses in vertically oriented laboratory columns packed with glass beads was investigated. Bacteriophages MS2 and ΦX174 were used as model viruses, and kaolinite (ΚGa-1b) and montmorillonite (STx-1b) as model clay colloids. A steady flow rate of Q=1.5 mL/min was applied in both vertical up (VU) and vertical down (VD) flow directions. In the presence of KGa-1b, estimated mass recovery values for both viruses were higher for VD than VU flow direction, while in the presence of STx-1b the opposite was observed. However, for all cases examined, the produced mass of viruses attached onto suspended clay particles were higher for VD than VU flow direction, suggesting that the flow direction significantly influences virus attachment onto clays, as well as packed column retention of viruses attached onto suspended clays. KGa-1b hindered the transport of ΦX174 under VD flow, while STx-1b facilitated the transport of ΦX174 under both VU and VD flow directions. Moreover, KGa-1b and STx-1b facilitated the transport of MS2 in most of the cases examined except of the case where KGa-1b was present under VD flow. Also, the experimental data were used for the estimation of virus surface-coverages and virus surface concentrations generated by virus diffusion-limited attachment, as well as virus attachment due to sedimentation. Both sedimentation and diffusion limited virus attachment were higher for VD than VU flow, except the case of MS2 and STx-1b cotransport. The diffusion-limited attachment was higher for MS2 than ΦΧ174 for all cases examined. PMID:26747984

  16. Clay particle retention in small constructed wetlands.

    Science.gov (United States)

    Braskerud, B C

    2003-09-01

    Constructed wetlands (CWs) can be used to mitigate non-point source pollution from arable fields. Previous investigations have shown that the relative soil particle retention in small CWs increases when hydraulic load increases. This paper investigates why this phenomenon occurs, even though common retention models predict the opposite, by studying clay and silt particle retention in two Norwegian CWs. Retention was measured with water flow proportional sampling systems in the inlet and outlet of the wetlands, and the texture of the suspended solids was analyzed. The surface area of the CWs was small compared to the watershed area (approximately 0.07%), giving high average hydraulic loads (1.1 and 2.0 md(-1)). One of the watersheds included only old arable land, whereas the other included areas with disturbed topsoil after artificial land leveling. Clay particle retention was 57% for the CW in the first watershed, and 22% for the CW in the disturbed watershed. The different behavior of the wetlands could be due to differences in aggregate size and stability of the particles entering the wetlands. Results showed that increased hydraulic loads did affect CW retention negatively. However, as runoff increased, soil particles/aggregates with higher sedimentation velocities entered the CWs (e.g., the clay particles behaved as silt particles). Hence, clay particle settling velocity is not constant as assumed in many prediction models. The net result was increased retention.

  17. Content of arsenic, selenium, mercury in the coal, food, clay and drinking water on the Zhaotong fluorosis area, eastern Yunnan Province

    Energy Technology Data Exchange (ETDEWEB)

    Luo Kun-li; Li Hui-jie; Chen Tong-bin (and others) [Chinese Academy of Sciences, Beijing (China). Institute of Geographic Sciences and Natural Resources Research

    2008-03-15

    About 160 samples of coal, corn, capsicum and drinking water were collected from the endemic fluorosis area of Zhenxiong and Weixin County, Zhaotong City of Yunnan Province, to determine the arsenic (As), selenium (Se) and mercury (Hg) content by AAF-800. The study found that the As content in the main coal seam from the Late Permian coal mines in Zhaotong City is 8.84 mg/kg and some civil coal can reach 89.09 mg/kg. The Se and Hg in the coal samples of Late Permian is lower, but Se and Hg are more concentrated in the pyritic coal balls and the pyritic gangue of the coal seam. The As content in corn and capsicum dried by coal-burning is more than 0.7 mg/kg, the natural standard amount of arsenic content permitted in food by China. The Se and Hg content in corn dried by coal-burning is lower than the natural standard of Se and Hg content in food in China but the Se and Hg content of capsicum dried by coal-burning exceeds the amount permitted by the natural standard for food in China. Clay, used as an additive for the coal-burning process and as a binder in making briquettes, contains a high content of As, generally more than 16 mg/kg. However, the Se and Hg content of clay itself are low. The As, Se and Hg content of drinking water are lower than the natural standard of As, Se and Hg content in the drinking water. So, there is high-As content coal and high-As content dried corn and capsicum in the endemic fluorosis area of Zhaotong City of Yunnan Province. The high As content of the dried corn and capsicum might have originated from the high arsenic content of burnt coal and clay. 30 refs., 4 tabs.

  18. The Boom Clay geochemistry: Natural evidence

    International Nuclear Information System (INIS)

    In Belgium, the Boom Clay is studied as the reference formation for geological disposal of high-level radioactive waste and spent fuel. As the Boom Clay is considered as the main barrier for radionuclide migration/retention, a thorough characterisation of the clay and its pore water was done. This facilitates better understanding of the long-term geological processes and the distribution of the trace elements and radionuclides. From a mineralogical/geochemical point of view, the Boom Clay is considered as a rather homogeneous sediment, vertically as well as laterally. It is composed of detrital minerals, organic matter and fossils. Minerals are mainly clay minerals, quartz and feldspars. Minor amounts of pyrite and carbonates are also present. Small variations in mineralogical/geochemical composition are related to granulometrical variations. The radiochemical study indicates that the Boom Clay is in a state of secular radioactive equilibrium, meaning that the Boom Clay has not been disturbed for a very long time. Pore water sampling is done in situ from various piezometers, or by the squeezing or leaching of clay cores in the laboratory. These three pore water sampling techniques have been compared and evaluated. Boom Clay pore water is a NaHCO3 solution of 15 mM, containing 115 mg·l-1 of dissolved natural organic carbon. Some slight variations in pore water composition have been observed and can be explained by principles of chemical equilibrium. (author)

  19. Calcium-ammonium exchange experiments on clay minerals using a (45)Ca tracer technique in marine pore water.

    Science.gov (United States)

    Ockert, Charlotte; Wehrmann, Laura M; Kaufhold, Stephan; Ferdelman, Tim G; Teichert, Barbara M A; Gussone, Nikolaus

    2014-01-01

    Understanding cation exchange processes is important for evaluating early diagenetic and synsedimentary processes taking place in marine sediments. To quantify calcium (Ca) exchange and Ca-ammonium exchange in a seawater environment, we performed experiments with a radioactive (45)Ca tracer on clay mineral standards (Fithian illite, montmorillonite and kaolinite) and marine sediments from the North Atlantic Integrated Ocean Drilling Program Site U1306A in artificial seawater (ASW). The results show that equilibrium during the initial attachment of Ca as well as the exchange of Ca by [Formula: see text] is attained in less than 2 min. On average 8-20% of the exchangeable sites of the clay minerals were occupied by Ca in a seawater medium. The conditional selectivity coefficient, describing the [Formula: see text] exchange in ASW is mineral specific and it was determined to be 0.07 for montmorillonite, 0.05 for a natural marine sediment and 0.013 for Fithian illite.

  20. Development and Characterisation of Nanoclays from Indian Clays

    OpenAIRE

    S. Manocha; Nikesh Patel; L. M. Manocha

    2008-01-01

    Indian clays are known for their smecticity. One such clay sample collected from Bhuj (Gujarat)was characterised and modified by successive sedimentation processes for different time intervals.The non-plastic components of clay, viz., quartz, illite, iron oxide, CaO, MgO, and organic matterwere removed in different steps, as the heavy impurities in the clay-water suspensions, settledown during sedimentation. The free iron oxide present in clay suspension was reduced bygiving sodium citrate-bi...

  1. General strategy, clay based disposal concepts and integration (GSI)

    International Nuclear Information System (INIS)

    This session gathers 20 articles (posters) dealing with: the assessment of backfill materials and methods for deposition tunnels; HTV-1: a semi technical scale testing of a multi-layer hydraulic shaft sealing system; the development of water content adjust method by mixing powdered-ice and chilled bentonite: application to the construction of bentonite engineered barriers by shot-clay method; repository design issues related to the thermal impact induced by heat emitting radioactive waste; pillared clays, using Romanian montmorillonite; the simulation of differential settlements of clay based engineered barrier systems in a geo-centrifuge; the critical issues regarding clay behaviour in the KBS-3H repository design; an alternative buffer material experiment; assessing the performance of a swelling clay tunnel seal and issues identified in the course of its operation; the activation of a Ca-bentonite as buffer material; a large diameter borehole type repository in the clays for radioactive waste long term storage; the erosion of backfill materials during the installation phase; the behaviour of the clay cover of a site for very low level nuclear waste: field flexion tests; the laboratory tests made on three different backfill candidates for the Swedish KBS- 3V concept; the engineering geological clay research for radioactive waste repository in Slovakia; the ESDRED project, module 1 - Design, fabrication, assembly, handling and packaging of buffer rings; the laboratory experiments on the sealing ability of bentonite pellets; the screening of bentonite resources for use as an engineered barrier component in deep geologic repositories; the assessment of the radionuclide release from the near-field environment of a spent nuclear fuel geological repository; and the emplacement tests with granular bentonite

  2. Experimental study of Human Adenoviruses interactions with clays

    Science.gov (United States)

    Bellou, Maria; Syngouna, Vasiliki; Paparrodopoulos, Spyros; Vantarakis, Apostolos; Chrysikopoulos, Constantinos

    2014-05-01

    Clays are used to establish low permeability liners in landfills, sewage lagoons, water retention ponds, golf course ponds, and hazardous waste sites. Human adenoviruses (HAdVs) are waterborne viruses which have been used as viral indicators of fecal pollution. The objective of this study was to investigate the survival of HAdV in static and dynamic clay systems. The clays used as a model were crystalline aluminosilicates: kaolinite and bentonite. The adsorption and survival of HAdVs onto these clays were characterized at two different controlled temperatures (4 and 25o C) under static and dynamic batch conditions. Control tubes, in the absence of clay, were used to monitor virus inactivation due to factors other than adsorption to clays (e.g. inactivation or sorption onto the tubes walls). For both static and dynamic batch experiments, samples were collected for a maximum period of seven days. This seven day time - period was determined to be sufficient for the virus-clay systems to reach equilibrium. To infer the presence of infectious HAdV particles, all samples were treated with Dnase and the extraction of viral nucleid acid was performed using a commercial viral RNA kit. All samples were analyzed by Real - Time PCR which was used to quantify viral particles in clays. Samples were also tested for virus infectivity by A549 cell cultures. Exposure time intervals in the range of seven days (0.50-144 hours) resulted in a load reduction of 0.74 to 2.96 logs for kaolinite and a reduction of 0.89 to 2.92 for bentonite. Furthermore, virus survival was higher onto bentonite than kaolinite (p

  3. CHEMICAL AND MINERALOGICAL CHARACTERISTICS OF FRENCH GREEN CLAYS USED FOR HEALING.

    Science.gov (United States)

    Williams, Lynda B; Haydel, Shelley E; Giese, Rossman F; Eberl, Dennis D

    2008-08-01

    The worldwide emergence of infectious diseases, together with the increasing incidence of antibiotic-resistant bacteria, elevate the need to properly detect, prevent, and effectively treat these infections. The overuse and misuse of common antibiotics in recent decades stimulates the need to identify new inhibitory agents. Therefore, natural products like clays, that display antibacterial properties, are of particular interest.The absorptive properties of clay minerals are well documented for healing skin and gastrointestinal ailments. However, the antibacterial properties of clays have received less scientific attention. French green clays have recently been shown to heal Buruli ulcer, a necrotic or 'flesh-eating' infection caused by Mycobacterium ulcerans. Assessing the antibacterial properties of these clays could provide an inexpensive treatment for Buruli ulcer and other skin infections.Antimicrobial testing of the two clays on a broad-spectrum of bacterial pathogens showed that one clay promotes bacterial growth (possibly provoking a response from the natural immune system), while another kills bacteria or significantly inhibits bacterial growth. This paper compares the mineralogy and chemical composition of the two French green clays used in the treatment of Buruli ulcer.Mineralogically, the two clays are dominated by 1Md illite and Fe-smectite. Comparing the chemistry of the clay minerals and exchangeable ions, we conclude that the chemistry of the clay, and the surface properties that affect pH and oxidation state, control the chemistry of the water used to moisten the clay poultices and contribute the critical antibacterial agent(s) that ultimately debilitate the bacteria. PMID:19079803

  4. Relationship between specific surface area and the dry end of the water retention curve for soils with varying clay and organic carbon contents

    DEFF Research Database (Denmark)

    Resurreccion, Augustus C.; Møldrup, Per; Tuller, Markus;

    2011-01-01

    dominate over capillary forces, have also been used to estimate soil specific surface area (SA). In the present study, the dry end of the SWRC was measured with a chilled-mirror dew point psychrometer for 41 Danish soils covering a wide range of clay (CL) and organic carbon (OC) contents. The 41 soils were...... with ethylene glycol monoethyl ether (SA_EGME) only for organic soils with n > 10. A strong correlation between the ratio of the two surface area estimates and the Dexter number was observed and applied as an additional scaling function in the TO model to rescale the soil water retention curve at low water...... and SA. It is therefore recommended to apply the empirical CSRN model for predicting the dry part of the water retention curve (−10 to −800 MPa) from measured soil texture or surface area. Further research should aim to modify the more physically based TO model to obtain better descriptions of the SWRC...

  5. Thermostability of montmorillonitic clays

    Directory of Open Access Journals (Sweden)

    Petr Jelínek

    2014-05-01

    Full Text Available Bentonite is one of the most widespread used clays connected with various applications. In the case of foundry technology, bentonite is primarily used as a binder for mold manufacture. Thermal stability of bentonites is a natural property of clay minerals and it depends on the genesis, source and chemical composition of the clay. This property is also closely connected to bentonite structure. According to DTA analysis if only one peak of dehydroxylation is observed (about 600 ºC, the cis- isomerism of bentonite is expected, while two peaks of de-hydroxylation (about 550 and 850 ºC are expected in the trans- one. In this overview, the bentonite structure, the water – bentonite interaction and the swelling behavior of bentonite in connection with the general technological properties of bentonite molding mixture are summarized. Further, various types of methods for determination of bentonite thermostability are discussed, including instrumental analytical methods as well as methods that employ evaluation of various technological properties of bentonite binders and/or bentonite molding mixtures.

  6. Thermostability of montmorillonitic clays

    Institute of Scientific and Technical Information of China (English)

    Petr Jelnek; Stanisaw M.Dobosz; Jaroslav Beo; Katarzyna Major-Gabry

    2014-01-01

    Bentonite is one of the most widespread used clays connected with various applications. In the case of foundry technology, bentonite is primarily used as a binder for mold manufacture. Thermal stability of bentonites is a natural property of clay minerals and it depends on the genesis, source and chemical composition of the clay. This property is also closely connected to bentonite structure. According to DTA analysis if only one peak of dehydroxylation is observed (about 600 ºC), thecis- isomerism of bentonite is expected, while two peaks of de-hydroxylation (about 550 and 850 ºC) are expected in thetrans- one. In this overview, the bentonite structure, the water - bentonite interaction and the sweling behavior of bentonite in connection with the general technological properties of bentonite molding mixture are summarized. Further, various types of methods for determination of bentonite thermostability are discussed, including instrumental analytical methods as wel as methods that employ evaluation of various technological properties of bentonite binders and/or bentonite molding mixtures.

  7. CATSIUS CLAY PROJECT: Calculation and testing of behaviour of unsaturated clay as barrier in radioactive waste repositories: stage 3: validation exercises at a large in situ scale

    International Nuclear Information System (INIS)

    Stage 3 of CATSIUS CLAY Project: Validation Exercises at a Large in situ Scale includes two Benchmarks: Benchmark 3.1: In situ Hydration of Boom Clay Pellets (BACCHUS 2) and Benchmark 3.2: FEBEX Mock-up Test. The BACCHUS 2 in situ test was performed in the HADES underground laboratory (Mol, Belgium) to demonstrate and optimize an installation procedure for a clay based material and to study its hydration process. After drilling a vertical shaft (540 mm in diameter, 3.0 m in length) in the host Boom clay, a central filter (90 mm in diameter) was placed, the remaining space was filled with a mixture of clay pellets and clay powder and the assembly was sealed at the upper end by a resin plug (0.20 m in thickness) over which concrete was poured. The test was instrumented so that it could be used as a validation experiment. Total stress, pore water pressure and water content measurements were performed both in the backfill material and in the surrounding clay massif. Once the installation was complete, the natural hydration of the backfill material began (day 0). To accelerate the hydration process, on day 516 water was injected through the central filter. On day 624, after the saturation of the backfill was reached, the hydraulic circuit was closed and the undrained response of the system backfill-host clay was monitored until an overall steady state was reached. Partners were asked to provide predictions for the evolution of the pore water pressure and total pressure of various points where appropriate sensors are installed. This benchmark addresses the Hydro-Mechanical response of an unsaturated low density clay barrier under natural and artificial hydration. (Author)

  8. CATSIUS CLAY PROJECT: Calculation and testing of behaviour of unsaturated clay as barrier in radioactive waste repositories: stage 3: validation exercises at a large in situ scale

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, E. E.; Alcoverro, J.

    1999-07-01

    Stage 3 of CATSIUS CLAY Project: Validation Exercises at a Large in situ Scale includes two Benchmarks: Benchmark 3.1: In situ Hydration of Boom Clay Pellets (BACCHUS 2) and Benchmark 3.2: FEBEX Mock-up Test. The BACCHUS 2 in situ test was performed in the HADES underground laboratory (Mol, Belgium) to demonstrate and optimize an installation procedure for a clay based material and to study its hydration process. After drilling a vertical shaft (540 mm in diameter, 3.0 m in length) in the host Boom clay, a central filter (90 mm in diameter) was placed, the remaining space was filled with a mixture of clay pellets and clay powder and the assembly was sealed at the upper end by a resin plug (0.20 m in thickness) over which concrete was poured. The test was instrumented so that it could be used as a validation experiment. Total stress, pore water pressure and water content measurements were performed both in the backfill material and in the surrounding clay massif. Once the installation was complete, the natural hydration of the backfill material began (day 0). To accelerate the hydration process, on day 516 water was injected through the central filter. On day 624, after the saturation of the backfill was reached, the hydraulic circuit was closed and the undrained response of the system backfill-host clay was monitored until an overall steady state was reached. Partners were asked to provide predictions for the evolution of the pore water pressure and total pressure of various points where appropriate sensors are installed. This benchmark addresses the Hydro-Mechanical response of an unsaturated low density clay barrier under natural and artificial hydration. (Author)

  9. Planning of experimental removal of cadmium in finite bath system using the chocolate clay B as adsorbent; Caracterizacao de adsorvente (argila chocolate B) visando a remocao de cadmio

    Energy Technology Data Exchange (ETDEWEB)

    Mota, J.D.; Rodrigues, M.G.F.; Lima, W.S.; Souza, R.S., E-mail: wsl_20@yahoo.com.br, E-mail: meiry@deq.ufcg.edu.br [Universidade Federal de Campina Grande (LABNOV/UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica. Lab. de Desenvolvimento de Novos Materiais

    2012-07-01

    The smectite clays are characterized by having a high cation exchange capacity and ability to remove metal ions. They have great industrial importance, for its abundance and low cost. The first part of this work was to characterize the clay called Chocolate B through the techniques of X-Ray Diffraction, X-Ray Spectroscopy and Energy Dispersive Physical Adsorption of Nitrogen. The second part of the work aims to evaluate the significance of the variables: pH and initial concentration on removal of cadmium in a batch system. In the experimental design used was a 2{sup 2} factorial analysis with the addition at the central point, and evaluated the percentage of removal (Rem%) and removal capacity (EQF). XRD results corroborating the chemical analysis (EDX), characterized as a B Chocolate smectite clays. Statistical analysis showed a strong influence of variable pH on the removal of cadmium. (author)

  10. Mars, clays and the origins of life

    Science.gov (United States)

    Hartman, Hyman

    1989-01-01

    To detect life in the Martian soil, tests were designed to look for respiration and photosynthesis. Both tests (labeled release, LR, and pyrolytic release, PR) for life in the Martian soils were positive. However, when the measurement for organic molecules in the soil of Mars was made, none were found. The interpretation given is that the inorganic constituents of the soil of Mars were responsible for these observations. The inorganic analysis of the soil was best fitted by a mixture of minerals: 60 to 80 percent clay, iron oxide, quartz, and soluble salts such as halite (NaCl). The minerals most successful in simulating the PR and LR experiments are iron-rich clays. There is a theory that considers clays as the first organisms capable of replication, mutation, and catalysis, and hence of evolving. Clays are formed when liquid water causes the weathering of rocks. The distribution of ions such as aluminum, magnesium, and iron play the role of bases in the DNA. The information was stored in the distribution of ions in the octahedral and tetrahedral molecules, but that they could, like RNA and DNA, replicate. When the clays replicated, each sheet of clay would be a template for a new sheet. The ion substitutions in one clay sheet would give rise to a complementary or similar pattern on the clay synthesized on its surface. It was theorized that it was on the surface of replicating iron-rich clays that carbon dioxide would be fixed in the light into organic acids such as formic or oxalic acid. If Mars had liquid water during a warm period in its past, clay formation would have been abundant. These clays would have replicated and evolved until the liquid water was removed due to cooling of Mars. It is entirely possible that the Viking mission detected life on Mars, but it was clay life that awaits the return of water to continue its evolution into life based on organic molecules.

  11. Structure, dynamics, and function of the hammerhead ribozyme in bulk water and at a clay mineral surface from replica exchange molecular dynamics.

    Science.gov (United States)

    Swadling, Jacob B; Wright, David W; Suter, James L; Coveney, Peter V

    2015-03-01

    Compared with proteins, the relationship between structure, dynamics, and function of RNA enzymes (known as ribozymes) is far less well understood, despite the fact that ribozymes are found in many organisms and are often conceived as "molecular fossils" of the first self-replicating molecules to have arisen on Earth. To investigate how ribozymal function is governed by structure and dynamics, we study the full hammerhead ribozyme in bulk water and in an aqueous clay mineral environment by computer simulation using replica-exchange molecular dynamics. Through extensive sampling of the major conformational states of the hammerhead ribozyme, we are able to show that the hammerhead manifests a free-energy landscape reminiscent of that which is well known in proteins, exhibiting a "funnel" topology that guides the ribozyme into its globally most stable conformation. The active-site geometry is found to be closely correlated to the tertiary structure of the ribozyme, thereby reconciling conflicts between previously proposed mechanisms for the self-scission of the hammerhead. The conformational analysis also accounts for the differences reported experimentally in the catalytic activity of the hammerhead ribozyme, which is reduced when interacting with clay minerals as compared with bulk water.

  12. Study on some rheological parameters of water and clay basis drilling fluids additivated with industrial sodium silicate; Estudo de alguns parametros reologicos de fluidos de perfuracao a base de agua e argila aditivados com silicato de sodio industrial

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Luciana Viana [Universidade Federal, Campina Grande, PB (Brazil). Engenharia de Processos]. E-mail: lucianaa@labdes.ufpb.br; Viana, Josiane Dantas; Farias, Kassie Vieira [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Engenharia de Materiais]. E-mail: josianedantas@bol.com.br; kassievieira@bol.com.br; Franca, Kepler Borges; Lira, Helio de Lucena; Ferreira, Heber Carlos [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Eng. Quimica]. E-mail: kepler@labdes.ufpb.br; helio@dema.ufpb.br; heber@dema.ufpb.br

    2003-07-01

    The aim of this work is to study some rheological parameters of water based oil well drilling fluids and bentonite clay from Boa Vista, PB, treated with industrial sodium silicate. It were selected there samples of natural polycationic bentonite clays and four industrial sodium bentonite clays. The natural clays were treated with concentrated Na{sub 2}CO{sub 3} solution. The drilling fluids were prepared with concentration of 4.86% w/w, according to PETROBRAS norms, and additivated with four different concentration of industrial sodium silicate. After 24 hours of cure, it were measured apparent viscosity (AV) and plastic viscosity (PV) by using a Fann 35A viscosimeter and water loss (WL) by using a Fann filter press. The results showed a change in the rheology of the drilling fluids. The drilling fluids prepared with industrialized clays showed a decrease in AV and an increase in WL. For the drilling fluids prepared with natural clays treated with Na{sub 2}CO{sub 3}, it was observed a decrease in AV and WL and an increase in PV. Also, it was observed a change in the drilling fluids state from flocculated-gel to a partially flocculated. (author)

  13. Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

    Science.gov (United States)

    Reynolds, Vernon; Lloyd, Andrew W; English, Christopher J; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

    2015-01-01

    Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms.

  14. Clay with Desiccation Cracks is an Advection Dominated Environment

    Science.gov (United States)

    Baram, S.; Kurtzman, D.; Sher, Y.; Ronen, Z.; Dahan, O.

    2012-04-01

    Heavy clay sediments are regarded "safe" from the hydrological point of view due to their low hydraulic conductivities. However, the formation of desiccation cracks in dispersive clays may dramatically change their bulk hydraulic properties. The impact of desiccation cracks on water percolation, dissolved salts and contaminants transport and redox related reactions (microbial ammonium oxidation and denitrification) were investigated in 6 -12 m clay layer near a diary farm waste lagoon. The study implemented unique vadose-zone monitoring systems that enable in-situ measurements of the temporal variation of the sediment's water content along with frequent sampling of the sediment's pore water along the entire vadose zone (> 30 m). Results from four years of continuous measurements showed quick rises in sediment water content following rain events and temporal wastewater overflows. The percolation pattern indicated dominance of preferential flow through a desiccation-cracks network crossing the entire clay sediment layer. High water-propagation velocities (0.4 - 23.6 m h-1) were observed, indicating that the desiccation-crack network remains open and serves as a preferential flow pathway year-round, even at high sediment water content (~0.50 m3 m-3). The rapid percolation bypassed the most bio-geo-active parts of the soil, transporting even highly sorptive contaminants (testosterone and estrogen) in to the deep sections of the vadose zone, accelerating the underlying groundwater contamination. The ammonium and nitrate concentrations in the vadose zone and the high number of nitrifying and denitrifying bacteria (~108 gene copies gdry-sediemt-1, each) found in the sediment indicated that the entire vadose zone is aerated even at high water content conditions (~0.55 m3 m-3). The dissolved salts concentration in the pore-water and the δ2H-H2O and δ18O-H2O values of the pore-water substantially increased with depth (becoming less depleted) in the clay sediment

  15. Water Hydraulic Systems

    DEFF Research Database (Denmark)

    Conrad, Finn

    2005-01-01

    The paper presents research results using IT-Tools for CAD and dynamic modelling, simulation, analysis, and design of water hydraulic actuators for motion control of machines, lifts, cranes and robots. Matlab/Simulink and CATIA are used as IT-Tools. The contributions include results from on......-going research projects on fluid power and mechatronics based on tap water hydraulic servovalves and linear servo actuators and rotary vane actuators for motion control and power transmission. Development and design a novel water hydraulic rotary vane actuator for robot manipulators. Proposed mathematical...... modelling, control and simulation of a water hydraulic rotary vane actuator applied to power and control a two-links manipulator and evaluate performance. The results include engineering design and test of the proposed simulation models compared with IHA Tampere University’s presentation of research...

  16. Effects of discharging acid-mine drainage into evaporation ponds lined with clay on chemical quality of the surrounding soil and water

    Science.gov (United States)

    Mapanda, F.; Nyamadzawo, G.; Nyamangara, J.; Wuta, M.

    Compacted clay layers are commonly used as liners to limit acid-mine drainage (AMD) percolation into the surrounding environment from containment areas or ponds. In the long term, this practical and sometimes economical means of AMD disposal has often presented other considerable environmental challenges. The chemical quality of soil, river water and groundwater surrounding evaporation ponds lined with clay was determined at Iron-Duke Mine in Glendale, Zimbabwe. At this mine over 150 m 3/d of wastewater containing AMD were discharged daily for over a decade. The soils located downslope in relation to the ponds and closer to the ponds were acidified (pH 2.8-4.4) and enriched with salts. The level of contamination was highest within 15 m from the ponds and at 2-6 m depths from the surface. The variability in soil pH and electrical conductivity with position, distance from the ponds and depth from surface was attributed to the vertical and lateral flow of contaminated groundwater containing leachates from the ponds. The groundwater and river water surrounding the ponds were contaminated with arsenic (As), iron (Fe), nickel (Ni), sulphate, salts and acidity, and the level of contamination increased with proximity to the ponds. Potential public health hazards from consumption of the groundwater and river water were high. It was concluded that discharging of AMD into the ponds has not been an environmentally effective means of AMD containment and disposal. There was need for better AMD disposal means, particularly those that would improve the containment of AMD to reduce its seepage.

  17. Water Treatment Technology - Distribution Systems.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on distribution systems provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: types of pipe for distribution systems, types…

  18. Measurement and conceptual modelling of herbicide transport to field drains in a heavy clay soil with implications for catchment-scale water quality management.

    Science.gov (United States)

    Tediosi, A; Whelan, M J; Rushton, K R; Thompson, T R E; Gandolfi, C; Pullan, S P

    2012-11-01

    Propyzamide and carbetamide are essential for blackgrass control in oilseed rape production. However, both of these compounds can contaminate surface waters and pose compliance problems for water utilities. The transport of propyzamide and carbetamide to an instrumented field drain in a small clay headwater tributary of the Upper Cherwell catchment was monitored over a winter season. Despite having very different sorption and dissipation properties, both herbicides were transported rapidly to the drain outlet in the first storm event after application, although carbetamide was leached more readily than propyzamide. A simple conceptual model was constructed to represent solute displacement from mobile pore water and preferential flow to drains. The model was able to reproduce the timing and magnitude of herbicide losses well, lending support to its conceptual basis. Measured losses in drainflow in the month following application were 1.1 and 8.1%, respectively, for propyzamide and carbetamide. Differences were due to a combination of differences in herbicide mobility and due to the fact that the monitoring period for carbetamide was hydrologically more active. For both compounds, losses were greater than those typically reported elsewhere for other herbicides. The data suggest that drainflow is the dominant pathway for the transfer of these herbicides to the catchment outlet, where water is abstracted for municipal supply. This imposes considerable constraints on the management options available to reduce surface water concentrations of herbicides in this catchment. PMID:22982449

  19. Philosophy of Education: A Thorn in the (Clay) Foot of the Educational System

    Science.gov (United States)

    Soetard, Michel

    2011-01-01

    The article tries to defend the thesis that our educational systems are not doing well (which is not at all original), that the philosophy of education, more often than not, accompanies, justifies and reinforces the malaise of the system (which is already more original), and that it should, without a doubt, question itself in order to know how to…

  20. Operational Management System for Regulated Water Systems

    Science.gov (United States)

    van Loenen, A.; van Dijk, M.; van Verseveld, W.; Berger, H.

    2012-04-01

    Most of the Dutch large rivers, canals and lakes are controlled by the Dutch water authorities. The main reasons concern safety, navigation and fresh water supply. Historically the separate water bodies have been controlled locally. For optimizating management of these water systems an integrated approach was required. Presented is a platform which integrates data from all control objects for monitoring and control purposes. The Operational Management System for Regulated Water Systems (IWP) is an implementation of Delft-FEWS which supports operational control of water systems and actively gives advice. One of the main characteristics of IWP is that is real-time collects, transforms and presents different types of data, which all add to the operational water management. Next to that, hydrodynamic models and intelligent decision support tools are added to support the water managers during their daily control activities. An important advantage of IWP is that it uses the Delft-FEWS framework, therefore processes like central data collection, transformations, data processing and presentation are simply configured. At all control locations the same information is readily available. The operational water management itself gains from this information, but it can also contribute to cost efficiency (no unnecessary pumping), better use of available storage and advise during (water polution) calamities.

  1. Study of smectite clays of the city Pedra Lavrada - PB for use in water-based drilling fluids; Estudo das argilas esmectiticas do municipio de Pedra Lavrada-PB para uso em fluidos de perfuracao base agua

    Energy Technology Data Exchange (ETDEWEB)

    Silva, I.A. da; Costa, J.M.R.; Cardoso, M.A.F.; Neves, G.A.; Ferreira, H.C., E-mail: isabelle_albuquerquecg@hotmail.com [Universidade Federal de Campina Grande (UAEMa/CCT/UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Ferreira, H.S. [Universidade Federal da Paraiba (DEMAT/CT/UFPB), Joao Pessoa, PB (Brazil)

    2011-07-01

    Paraiba has large reserves of bentonite clays, with the largest deposits in Boa Vista, PB. Recently new deposits were discovered in the cities of Cubati and Pedra Lavrada-PB, creating great expectations for further expansion of reserves for industrial production. The aim of this work is the study of smectite clays from the city of Pedra Lavrada, PB for use in drilling fluids water based. The characterization was made by the diffraction of laser (AG), thermogravimetric and differential thermal analysis (TGA and DTA), chemical composition by X-ray fluorescence (EDX), X-ray diffraction (XRD), exchange capacity of cations (ECC) and surface area (SA). The results obtained so far showed that the samples presented at its mineral composition smectite, kaolinite and quartz. In relation to rheological properties showed that the bentonite clay sample Dark presents promising features for use in water based drilling fluids. (author)

  2. Water Supply Infrastructure System Surety

    Energy Technology Data Exchange (ETDEWEB)

    EKMAN,MARK E.; ISBELL,DARYL

    2000-01-06

    The executive branch of the United States government has acknowledged and identified threats to the water supply infrastructure of the United States. These threats include contamination of the water supply, aging infrastructure components, and malicious attack. Government recognition of the importance of providing safe, secure, and reliable water supplies has a historical precedence in the water works of the ancient Romans, who recognized the same basic threats to their water supply infrastructure the United States acknowledges today. System surety is the philosophy of ''designing for threats, planning for failure, and managing for success'' in system design and implementation. System surety is an alternative to traditional compliance-based approaches to safety, security, and reliability. Four types of surety are recognized: reactive surety; proactive surety, preventative surety; and fundamental, inherent surety. The five steps of the system surety approach can be used to establish the type of surety needed for the water infrastructure and the methods used to realize a sure water infrastructure. The benefit to the water industry of using the system surety approach to infrastructure design and assessment is a proactive approach to safety, security, and reliability for water transmission, treatment, distribution, and wastewater collection and treatment.

  3. Gas migration through bentonite clay

    International Nuclear Information System (INIS)

    Hydrogen gas produced by irradiation of pore water in the highly compacted bentonite that surrounds the copper canisters according to the KBS 2 and 3 concepts, may escape from the clay/copper interface if the gas pressure is higher than the groundwater pressure. A reasonable physical model predicts that gas may penetrate wider capillary passages that actually exist in the very dense clay, although these passages are still of microscopic size. In the large majority of the clay voids, the capillary action is sufficient, however, to resist gas penetration, and this suggests that a possible mechanism of gas migration is that of a finger-like pattern of tortuous gas passages extending from the canisters if radiolysis takes place at all. Two series of experiments have been run at gas pressures up to about 10 MPa. Nitrogen as well as hydrogen were used in these tests which seem to confirm, in principle, the validity of the physical model. (authors)

  4. Electrolyte low concentrations effects on the the rheology of water and bentonitic clays basis drilling fluids; Efeito de baixas concentracoes de eletrolitos na reologia de fluidos de perfuracao a base de agua e argilas bentoniticas

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Luciana Viana [Universidade Federal, Campina Grande, PB (Brazil). Engenharia de Processos]. E-mail: lucianaa@labdes.ufpb.br; Viana, Josiane Dantas; Farias, Kassie Vieira; Lira, Helio de Lucena; Ferreira, Heber Carlos [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Engenharia de Materiais]. E-mail: josianedantas@bol.com.br; kassievieira@bol.com.br; helio@dema.ufpb.br; heber@dema.ufpb.br; Franca, Kepler Borges [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Engenharia Quimica]. E-mail: kepler@labdes.ufpb.br

    2003-07-01

    The aim of this work is to study the effect of low electrolytes concentration on the rheology of the water based oil well drilling fluids and bentonite clays from Boa Vista, PB. It were selected seven samples of bentonite clays (four from industry and three from natural polycationic clay treated with concentrated Na{sub 2}CO{sub 3} solution). The drilling fluids were prepared with a concentration of 4.86 % w/w, according to PETROBRAS norms and treated with different CaCl{sub 2} + MgCl{sub 2} concentration. After, the drilling fluids were submitted to a cure for 24 hours and measured apparent viscosity (AV), plastic viscosity (PV) and water loss (WL). To study the effect of the electrolyte on the rheology of the dispersions it was developed a factorial design 2{sup 2} + 3 test in the central point. The results showed that the addition of CaCl{sub 2} + MgCl{sub 2} caused a degradation of the drilling fluids prepared with industrialized clays, as showed by the decrease in AV and PV and great increase in WL. Also, it was observed an increase in AV and a decrease in PV in the drilling fluids prepared with natural clays treated with Na{sub 2}CO{sub 3}, conducting a flocculated-gel state. (author)

  5. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    Science.gov (United States)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    While most magnetic resonance imaging (MRI) applications concern medical research, there is a rapidly increasing number of MRI studies in the field of environmental science and technology. In this presentation, MRI will be introduced from the latter perspective. While many processes in these areas are similar to those addressed in medical applications of MRI, parameters and experimental implementations are often quite different and, in many respects, far more demanding. This hinders direct transfer of existing methods developed for biomedical research, especially when facing the challenging task of obtaining spatially resolved quantitative information. In MRI investigation of soils, clays, and rocks, mainly water signal is detected, similarly to MRI of biological and medical samples. However, a strong variation of water mobility and a wide spread of water spin relaxation properties in these materials make it difficult to use standard MRI approaches. Other significant limitations can be identified as following: T2 relaxation and probe dead time effects; molecular diffusion artifacts; varying dielectric losses and induced currents in conductive samples; limited dynamic range; blurring artifacts accompanying drive for increasing sensitivity and/or imaging speed. Despite these limitations, by combining MRI techniques developed for solid and liquid states and using independent information on relaxation properties of water, interacting with the material of interest, true images of distributions of both water, material and molecular properties in a wide range of concentrations can be obtained. Examples of MRI application will be given in the areas of soil and mineral research where understanding water transport and erosion processes is one of the key challenges. Efforts in developing and adapting MRI approaches to study these kinds of systems will be outlined as well. Extensive studies of clay/water interaction have been carried out in order to provide a quantitative

  6. Clays in natural and engineered barriers for radioactive waste confinement - 4. International meeting. Book of abstracts

    International Nuclear Information System (INIS)

    proposed within the Strategic Research Agenda, elaborated through the Implementing Geological Disposal of Radioactive Waste Technology Platform (IGD-TP). The conference offers a particular opportunity to present the more recent developments and main outputs of research carried out within the framework of national and international cooperative experiments and dedicated European projects. Contributions coming from fields other than radioactive waste disposal; like geological storage of natural gas, sequestration of CO2, energy storage in underground, chemical waste isolation, etc., also taking advantage of the properties of the clay material, were encouraged. This conference covers all topics concerning the natural argillaceous geological barriers and the clay-based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties) and monitoring. General strategy for clay based repository concepts Examples of research programmes (national or international) concerning the role of natural and engineered clay barriers for radioactive waste confinement including repository designs, safety assessment, full-scale demonstrations and implementations (e.g. heater tests). Geology and clay characterisation Clay mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in clay rock, fracturing, self-sealing processes, role of organic matters and microbiological processes, micro and nano characterisation of clay minerals and argillaceous rocks. Geochemistry Pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry. Mass transfer Water status and hydraulic properties in low permeability media, pore space

  7. ALCOHOL FLUSHING FOR REMOVING DNAPL'S FROM CLAY AND SAND LAYERED AQUIFER SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    N.J. Hayden; P. Padgett; C. Farrell; J. Diebold; X. Zhou; M. Hood

    1999-08-01

    Alcohol flushing, also called cosolvent flushing, is a relatively new in-situ remediation technology that shows promise for removing organic solvents from the soil and groundwater. Soil and groundwater contamination from organic solvents and petroleum products is one of the most serious and widespread environmental problems of our time. Most of the DOE facilities and inactive sites are experiencing soil and groundwater contamination from organic solvents. These water immiscible solvents have entered the subsurface from leaking underground storage tanks and piping, and from past waste handling and disposal practices such as leaking lagoons, holding ponds and landfills. In many cases, they have traveled hundreds of feet down into the saturated zone. If left in the soil, these chemicals may pose a significant environmental and human health risk. Alcohol flushing has potential for application to spilled solvents located deep within the saturated zone which are difficult if not impossible to remove by current remediation strategies, thus, greatly expediting restoration time, reducing total remediation cost and reducing risk.

  8. Montmorillonite Clay-Based Polyurethane Nanocomposite As Local Triamcinolone Acetonide Delivery System

    OpenAIRE

    Flávia Carmo Horta Pinto; Armando Silva-Cunha; Gerson Antônio Pianetti; Eliane Ayres; Rodrigo Lambert Oréfice; Gisele Rodrigues Da Silva

    2011-01-01

    Biodegradable polyurethane was synthesized by preparing aqueous polyurethane dispersion having poly(caprolactone) and poly(ethylene glycol) as soft segments. Montmorillonite particles were delaminated within the waterborne polyurethane to produce a nanocomposite. The triamcinolone acetonide (TA), an important corticoid drug, was dispersed into the nanocomposite followed by a drying step to produce an implantable drug delivery system. Infrared (FTIR) results demonstrated that the original chem...

  9. Biodegradation behaviors and water adsorption of poly(vinyl alcohol)/starch/carboxymethyl cellulose/clay nanocomposites

    Science.gov (United States)

    Taghizadeh, Mohammad Taghi; Sabouri, Narges

    2013-09-01

    The focus of this work is to study the effect of sodium montmorillonite (MMT-Na) clay content on the rate and extent of enzymatic hydrolysis polyvinyl alcohol (PVA)/starch (S)/carboxymethyl cellulose (CMC) blends using enzyme cellulase. The rate of glucose production from each nanocomposite substrates was most rapid for the substrate without MMT-Na and decreased with the addition of MMT-Na for PVA/S/CMC blend (51.5 μg/ml h), PVA/S/CMC/1% MMT (45.4 μg/ml h), PVA/S/CMC/3% MMT (42.8 μg/ml h), and PVA/S/CMC/5% MMT (39.2 μg/ml h). The results of this study have revealed that films with MMT-Na content at 5 wt.% exhibited a significantly reduced rate and extent of hydrolysis. Enzymatic degradation behavior of MMT-Na containing nanocomposites of PVA/S/CMC was based on the determinations of weight loss and the reducing sugars. The degraded residues have been characterized by various analytical techniques, such as Fourier transform infrared spectroscopy, scanning electronic microscopy, and UV-vis spectroscopy.

  10. Water in the Solar System

    Science.gov (United States)

    Encrenaz, Thérèse

    2008-09-01

    Water is ubiquitous in the Universe, and also in the Solar System. By setting the snow line at its condensation level in the protosolar disk, water was responsible for separating the planets into the terrestrial and the giant ones. Water ice is a major constituent of the comets and the small bodies of the outer Solar System, and water vapor is found in the giant planets, both in their interiors and in the stratospheres. Water is a trace element in the atmospheres of Venus and Mars today. It is very abundant on Earth, mostly in liquid form, but it was probably also abundant in the primitive atmospheres of Venus and Mars. Water is found in different states on the three planets, as vapor on Venus and ice (or permafrost) on Mars. Most likely, this difference has played a major role in the diverging destinies of the three planets.

  11. Lake responses following lanthanum-modified bentonite clay (Phoslock®) application: an analysis of water column lanthanum data from 16 case study lakes.

    Science.gov (United States)

    Spears, Bryan M; Lürling, Miquel; Yasseri, Said; Castro-Castellon, Ana T; Gibbs, Max; Meis, Sebastian; McDonald, Claire; McIntosh, John; Sleep, Darren; Van Oosterhout, Frank

    2013-10-01

    Phoslock(®) is a lanthanum (La) modified bentonite clay that is being increasingly used as a geo-engineering tool for the control of legacy phosphorus (P) release from lake bed sediments to overlying waters. This study investigates the potential for negative ecological impacts from elevated La concentrations associated with the use of Phoslock(®) across 16 case study lakes. Impact-recovery trajectories associated with total lanthanum (TLa) and filterable La (FLa) concentrations in surface and bottom waters were quantified over a period of up to 60 months following Phoslock(®) application. Both surface and bottom water TLa and FLa concentrations were modelling indicated that recovery trajectories for TLa and FLa in surface and bottom waters in lakes were represented by 2nd order decay relationships, with time, and that recovery reached an end-point between 3 and 12 months post-application. Recovery in bottom water was slower (11-12 months) than surface waters (3-8 months), most probably as a result of variation in physicochemical conditions of the receiving waters and associated effects on product settling rates and processes relating to the disturbance of bed sediments. CHEAQS PRO modelling was also undertaken on 11 of the treated lakes in order to predict concentrations of La(3+) ions and the potential for negative ecological impacts. This modelling indicated that the concentrations of La(3+) ions will be very low (0.8 mEq L(-1)), but higher (up to 0.12 mg L(-1)) in lakes characterised by very low alkalinity. The effects of elevated La(3+) concentrations following Phoslock(®) applications in lakes of very low alkalinity requires further evaluation. The implications for the use of Phoslock(®) in eutrophication management are discussed. PMID:23911225

  12. The Exploration Water Recovery System

    Science.gov (United States)

    ORourke, Mary Jane E.; Carter, Layne; Holder, Donald W.; Tomes, Kristin M.

    2006-01-01

    The Exploration Water Recovery System is designed towards fulfillment of NASA s Vision for Space Exploration, which will require elevation of existing technologies to higher levels of optimization. This new system, designed for application to the Exploration infrastructure, presents a novel combination of proven air and water purification technologies. The integration of unit operations is modified from that of the current state-of-the-art water recovery system so as to optimize treatment of the various waste water streams, contaminant loads, and flow rates. Optimization is achieved primarily through the removal of volatile organic contaminants from the vapor phase prior to their absorption into the liquid phase. In the current state-of-the-art system, the water vapor in the cabin atmosphere is condensed, and the volatile organic contaminants present in that atmosphere are absorbed into the aqueous phase. Removal of contaminants the5 occurs via catalytic oxidation in the liquid phase. Oxidation kinetics, however, dictate that removal of volatile organic contaminants from the vapor phase can inherently be more efficient than their removal from the aqueous phase. Taking advantage of this efficiency reduces the complexity of the water recovery system. This reduction in system complexity is accompanied by reductions in the weight, volume, power, and resupply requirements of the system. Vapor compression distillation technology is used to treat the urine, condensate, and hygiene waste streams. This contributes to the reduction in resupply, as incorporation of vapor compression distillation technology at this point in the process reduces reliance on the expendable ion exchange and adsorption media used in the current state-of-the-art water recovery system. Other proven technologies that are incorporated into the Exploration Water Recovery System include the Trace Contaminant Control System and the Volatile Removal Assembly.

  13. Polymer based nanocomposites with nanofibers and exfoliated clay

    Science.gov (United States)

    Meador, Michael A.; Reneker, Darrell H.

    2005-01-01

    Polymer solutions, containing clay sheets, were electrospun into nanofibers and microfibers that contained clay sheets inside. Controllable removal of polymer by plasma etching from the surface of fibers revealed the arrangement of clay. The shape, flexibility, size distribution and arrangement of clay sheets were observed by transmission and scanning electron microscopy. The clay sheets were partially aligned in big fibers with normal direction of clay sheets perpendicular to fiber axis. Crumpling of clay sheets inside fibers was observed when the fiber diameter was comparable to the lateral size of clay sheets. Single sheets of clay were observed both by catching clay sheets dispersed in water with electrospun nanofiber mats and by the deliberate removal of most of the polymer in the fibers. Thin, flexible gas barrier films, that are reasonably strong, were assembled from clay sheets and polymer nanofibers. Structure of composite films was characterized with scanning electron microscopy. Continuous film of clay sheets were physically attached to the surface of fiber mats. Spincoating film of polymer and clay sheets was reinforced by electrospun fiber scaffold. Certain alignment of clay sheets was observed in the vicinity of fibers.

  14. Semi-permeable vesicles composed of natural clay

    OpenAIRE

    Subramaniam, Anand B.; Wan, Jiandi; Gopinath, Arvind; Stone, Howard A.

    2010-01-01

    We report a simple route to form robust, inorganic, semi-permeable compartments composed of montmorillonite, a natural plate-like clay mineral that occurs widely in the environment. Mechanical forces due to shear in a narrow gap assemble clay nanoplates from an aqueous suspension onto air bubbles. Translucent vesicles suspended in a single-phase liquid are produced when the clay-covered air bubbles are exposed to a variety of water-miscible organic liquids. These vesicles of clay are mechanic...

  15. Effect of aging on rheology of ball clay suspensions

    Science.gov (United States)

    Tonthai, Tienchai

    2002-01-01

    The behaviors of clay-water suspensions such as deflocculation or rheological properties are not constant but change with time. Aging has been recognized for changing the rheological properties of clay suspensions. This work provided information about the effects of the moisture contents in ball clay lumps and clay air exposure time on their processability. Dynamic oscillatory rheometry using a vane-in-cup geometry was used to characterize the rheological behavior of ball clay suspensions in terms of elastic modulus, viscous modulus and yield stress as a function of aging time. A light scattering size analyzer was used to examine the agglomerate size distribution of ball clay suspensions which affected the rheological behavior. Soluble ion release (both cations and anions) in the filtrate of suspensions was measured by ion chromatography. Low and high lignitic ball clay suspensions were dispersed with sodium silicate (Na2SiO3) or sodium polyacrylate at specific gravity 1.3 and 1.6 in two dispersion states: fully deflocculated (minimum viscosity) and under deflocculated. Suspensions prepared using freshly mined ball clays required more dispersant than suspensions prepared using dry ball clays to achieve minimum viscosity due to a difference in agglomerate size distribution. The agglomerate size distribution of suspensions prepared using dry clays was broader than that of suspensions prepared using freshly mined clays. In suspensions prepared using freshly mined clays, there were many uniformly small agglomerates having loose water inside, while in suspensions prepared using dry clays, the capillary effect and bonding between clay particles resulting from drying broke clay aggregates apart into agglomerate structures composed of a few to many clay particles. For suspensions prepared using dry clays after one day suspension aging, the elastic modulus and yield stress decreased due to the change in agglomerate size distribution of suspensions but increased for

  16. Disturbance of water-extractable phosphorus determination by colloidal particles in a heavy clay soil from the Netherlands

    NARCIS (Netherlands)

    Koopmans, G.F.; Chardon, W.J.; Salm, van der C.

    2005-01-01

    Received for publication January 25, 2005. Water extraction methods are widely used to extract phosphorus (P) from soils for both agronomic and environmental purposes. Both the presence of soil colloids in soil water filtrates, and the contribution of colloidal P to the molybdate-reactive phosphorus

  17. Quantitative approach on SEM images of microstructure of clay soils

    Institute of Scientific and Technical Information of China (English)

    施斌; 李生林; M.Tolkachev

    1995-01-01

    The working principles of Videolab Image Processing System (VIPS), the examining methods of orientation of microstructural units of clay soils and analysing results on SEM images of some typical microstructures of clay soils using the VIPS are introduced.

  18. Characterization of Swelling Clays as Components of the Engineered Barrier System for Geological Repositories. Results of an IAEA Coordinated Research Project 2002-2007

    International Nuclear Information System (INIS)

    At the request of the Member States, the IAEA coordinates research into subjects of common interest in the context of the peaceful application of nuclear technology. The coordinated research projects (CRPs) are intended to promote knowledge and technology transfer between Member States and are largely focused on subjects of prime interest to the international nuclear community. This report presents the results of a CRP carried out between 2002 and 2007 on the subject of swelling clays proposed for use as a component in the engineered barrier system (EBS) of the multibarrier concept for disposal of radioactive waste. In 2002, under the auspices of the IAEA, a number of Member States came together to form a Network of Centres of Excellence on Training in and Demonstration of Waste Disposal Technologies in Underground Research Facilities (URF Network). This network identified the general subject of the application of high swelling clays to seal repositories for radioactive waste, with specific emphasis on the isolation of high level radioactive waste from the biosphere, as being suitable for a CRP. Existing concepts for geological repositories for high level radioactive waste and spent nuclear fuel require the use of EBSs to ensure effective isolation of the radioactive waste. There are two major materials proposed for use in the EBS, swelling clay based materials and cementitious/concrete materials. These materials will be placed between the perimeter of the excavation and the waste container to fill the existing gap and ensure isolation of the waste within the canister (also referred to as a container in some EBS concepts) by supporting safety through retardation and confinement. Cementitious materials are industrially manufactured to consistent standards and are readily available in most locations and therefore their evaluation is of less value to Member States than that of swelling clays. There exists a considerable range of programme development regarding

  19. Water drilling fluids: evaluation of lubricity and clay swelling control; Fluidos de perfuracao a base de agua: avaliacao de lubricidade e controle de inchamento de argilas

    Energy Technology Data Exchange (ETDEWEB)

    Felix, Thiago de Freitas; Arruda, Jefferson Teixeira; Medeiros, Ana Catarina; Garcia, Rosangela Balaban [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    During the oil well drilling, drilling fluids are used in order to transport the cuttings until the surface. This fluid is also responsible for the mechanical sustentation of the well walls, the control of undesirable production of fluids in the formation, the lubricity and the cooling of the bit. The drilling fluids based on water are extensively applied due to their lower cost, thermal stability, biodegradability, easiness of pumping and treatment, resulting in smaller environmental impacts. However, some situations, such as hydrophilic shale drilling, request the use of additives to avoid the hydration of them and, consequently, the tool imprisonment or migration (filtration) of the drilling fluids into the rock. The goal of this work was to develop and test formulations of water-base drilling fluids with high capacity of inhibition of clay swelling and lubricity, obtaining drillings with larger penetration rate and calipers without enlargements. The results showed that the appropriate combination of commonly used commercial products can promote the obtaining of fluids with equal or better performance than those used by world companies. (author)

  20. Potential for Recycling Nutrients from Biosolids Amended with Clay and Lime in Coarse-Textured Water Repellence, Acidic Soils of Western Australia

    Directory of Open Access Journals (Sweden)

    Sanjutha Shanmugam

    2015-01-01

    Full Text Available Application of biosolids in soils is an efficient method of recycling nutrients from biosolids and it is considered even safer when it is modified after mixing and diluting with other suitable soil organic amendments. A variety of soil organic amendments, such as green manures and composts, are used for modifying and co-composting with biosolids. However, these may not be considered as appropriate biosolids disposal and remedial measures for soils with unique problems such as low soil pH, water repellence nature, and poor water and nutrient retention capacities due to soil textural issues. Historically, soil amendments such as lime, clay, and recently biochar are being applied for such problematic soils at Western Australia and these researches focused mostly on improvement in soil physical and chemical properties. However, studies with potential for applying modified biosolids with these amendments are not complete yet. This review focused on identifying such gaps in these studies from over 170 peer-reviewed key research and review articles published over decades to latest in these areas.

  1. Immobilization of fungal laccase onto a nonionic surfactant-modified clay material: application to PAH degradation.

    Science.gov (United States)

    Chang, Yi-Tang; Lee, Jiunn-Fwu; Liu, Keng-Hua; Liao, Yi-Fen; Yang, Vivian

    2016-03-01

    Nonionic surfactant-modified clay is a useful absorbent material that effectively removes hydrophobic organic compounds from soil/groundwater. We developed a novel material by applying an immobilized fungal laccase onto nonionic surfactant-modified clay. Low-water-solubility polycyclic aromatic hydrocarbons (PAHs) (naphthalene/phenanthrene) were degraded in the presence of this bioactive material. PAH degradation by free laccase was higher than degradation by immobilized laccase when the surfactant concentration was allowed to form micelles. PAH degradation by immobilized laccase on TX-100-modified clay was higher than on Brij35-modified clay. Strong laccase degradation of PAH can be maintained by adding surfactant monomers or micelles. The physical adsorption of nonionic surfactants onto clay plays an important role in PAH degradation by laccase, which can be explained by the structure and molecular interactions of the surfactant with the clay and enzyme. A system where laccase is immobilized onto TX-100-monomer-modified clay is a good candidate bioactive material for in situ PAHs bioremediation.

  2. Brazilian clay organophilization aiming its use in oil / water removal; Organofilizacao de argila brasileira visando seu uso na remocao oleo/agua

    Energy Technology Data Exchange (ETDEWEB)

    Mota, M.F.; Lima, W.S.; Oliveira, G.C.; Silva, M.M.; Rodrigues, M.G.F., E-mail: mariaugusta.f@gmail.com, E-mail: meiry@deq.ufcg.edu.br [Universidade Federal de Campina Grande (LABNOV/UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica. Lab. de Desenvolvimento de Novos Materiais

    2012-07-01

    Clays when subjected to modification with the addition of organic surfactant are called organoclays acquire hydrophobic character, they have an affinity for organic compounds. The organoclays can be used as adsorbents are considered promising agents in environmental control. The objective is to prepare organoclays clays from commercial use in order to remove organic contaminants. The clay used was gray, as polycationic, supplied by Süd-Chemie company and the quaternary ammonium salt was cetyltrimethylammonium bromide (Cetremide). The fresh samples and organoclay were characterized by the technique of X-ray diffraction (XRD), Cation Exchange Capacity, testing expansion and affinity with organic compounds: Swelling of Foster and adsorption capacity. The results showed appropriate conditions organophilic process. Through XRD confirmed the increase in basal spacing for the modified clay in relation to the clay in nature. (author)

  3. [Mechanism of tritium persistence in porous media like clay minerals].

    Science.gov (United States)

    Wu, Dong-Jie; Wang, Jin-Sheng; Teng, Yan-Guo; Zhang, Ke-Ni

    2011-03-01

    To investigate the mechanisms of tritium persistence in clay minerals, three types of clay soils (montmorillonite, kaolinite and illite) and tritiated water were used in this study to conduct the tritium sorption tests and the other related tests. Firstly, the ingredients, metal elements and heat properties of clay minerals were studied with some instrumental analysis methods, such as ICP and TG. Secondly, with a specially designed fractionation and condensation experiment, the adsorbed water, the interlayer water and the structural water in the clay minerals separated from the tritium sorption tests were fractionated for investigating the tritium distributions in the different types of adsorptive waters. Thirdly, the location and configuration of tritium adsorbed into the structure of clay minerals were studied with infrared spectrometry (IR) tests. And finally, the forces and mechanisms for driving tritium into the clay minerals were analyzed on the basis of the isotope effect of tritium and the above tests. Following conclusions have been reached: (1) The main reason for tritium persistence in clay minerals is the entrance of tritium into the adsorbed water, the interlayer water and the structural water in clay minerals. The percentage of tritium distributed in these three types of adsorptive water are in the range of 13.65% - 38.71%, 0.32% - 5.96%, 1.28% - 4.37% of the total tritium used in the corresponding test, respectively. The percentages are different for different types of clay minerals. (2) Tritium adsorbed onto clay minerals are existed in the forms of the tritiated hydroxyl radical (OT) and the tritiated water molecule (HTO). Tritium mainly exists in tritiated water molecule for adsorbed water and interlayer water, and in tritiated hydroxyl radical for structural water. (3) The forces and effects driving tritium into the clay minerals may include molecular dispersion, electric charge sorption, isotope exchange and tritium isotope effect.

  4. Onsite Waste Water Treatment System

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-06-01

    Full Text Available Onsite wastewater treatment systems (OWTSs have evolved from the pit privies used widely throughout history to installations capable of producing a disinfected effluent that is fit for human consumption. Although achieving such a level of effluent quality is seldom necessary, the ability of onsite systems to remove settles able solids, floatable grease and scum, nutrients, and pathogens. From wastewater discharges defines their importance in protecting human health and environmental resources. In the modern era, the typical onsite system has consisted primarily of a septic tank and a soil absorption field, also known as a subsurface wastewater infiltration system, or SWIS. In this manual, such systems are referred to as conventional systems. Septic tanks remove most settle able and floatable material and function as an anaerobic bioreactor that promotes partial digestion of retained organic matter. Septic tank effluent, which contains significant concentrations of pathogens and nutrients, has traditionally been discharged to soil, sand, or other media absorption fields (SWISs for further treatment through biological processes, adsorption, filtration, and infiltration into underlying soils. Conventional systems work well if they are installed in areas with appropriate soils and hydraulic capacities; designed to treat the incoming waste load to meet public health, ground water, and surface water performance standards; installed properly; and maintained to ensure long-term performance. These criteria, however, are often not met. Only about one-third of the land area in the United States has soils suited for conventional subsurface soil absorption fields. System densities in some areas exceed the capacity of even suitable soils to assimilate wastewater flows and retain and transform their contaminants. In addition, many systems are located too close to ground water or surface waters and others, particularly in rural areas with newly installed public

  5. Assessment on reliability of water quality in water distribution systems

    Institute of Scientific and Technical Information of China (English)

    伍悦滨; 田海; 王龙岩

    2004-01-01

    Water leaving the treatment works is usually of a high quality but its properties change during the transportation stage. Increasing awareness of the quality of the service provided within the water industry today and assessing the reliability of the water quality in a distribution system has become a major significance for decision on system operation based on water quality in distribution networks. Using together a water age model, a chlorine decay model and a model of acceptable maximum water age can assess the reliability of the water quality in a distribution system. First, the nodal water age values in a certain complex distribution system can be calculated by the water age model. Then, the acceptable maximum water age value in the distribution system is obtained based on the chlorine decay model. The nodes at which the water age values are below the maximum value are regarded as reliable nodes. Finally, the reliability index on the percentile weighted by the nodal demands reflects the reliability of the water quality in the distribution system. The approach has been applied in a real water distribution network. The contour plot based on the water age values determines a surface of the reliability of the water quality. At any time, this surface is used to locate high water age but poor reliability areas, which identify parts of the network that may be of poor water quality. As a result, the contour water age provides a valuable aid for a straight insight into the water quality in the distribution system.

  6. Changes in grain-size and sedimentation rate of the Neogene Red Clay deposits along the Chinese Loess Plateau and implications for the palaeowind system

    Institute of Scientific and Technical Information of China (English)

    WEN Lingjuan; LU Huayu; QIANG Xiaoke

    2005-01-01

    The wind system responsible for transporting dust onto the Chinese Loess Plateau during the late Miocene and Pliocene is still unknown and recent investigations highlight many controversies. This report aims to investigate spatiotemporal changes in grain-size and sedimentation rate of the Neogene Red Clay deposits in north China and to explore palaeoclimatic changes during the late Miocene and Pliocene, in particular the palaeowind system that transported dust. Samples were collected from eight Red Clay sections on the Loess Plateau. Measurement and analysis show that there is a clear southward decrease in the mean grain-size index and in the coarse particle fraction (>20 μm). At Jiaxian site on the northern Loess Plateau, the average mean grain-size is around 20 μm, while at Lantian site in the south, the mean is around 9 μm. The coarse particle fraction >20 μm makes up 24.4% and 5.6%, at the two sites respectively. This distinct diversity of grain-size in the aeolian Red Clay deposit between the north and south indicate that the palaeodust was transported mainly by northerly low-level winds. The grain-size variations in the Red Clay deposits can also be divided into three stages (the lower, the middle and the upper interval): grain-size of the lower stage is significantly coarser than that of the middle stage, but finer than that of the upper stage. As a consequence, the intensity of palaeowind and desiccation of the dust source region during the late Miocene and Pliocene can be divided into three stages: 6.2-5.4 Ma, 5.4-3.5 Ma and 3.5-2.6 Ma. Strength of the palaeowind during the middle stage (5.4-3.5 Ma) is weaker than that of the previous and subsequent stages and the intensity of palaeowind during the latest stage (3.5-2.6 Ma) is stronger than that of the early time (6.2-5.4 Ma). Variations in the sedimentation rate of the Red Clay deposit can also be divided into three stages: the earlier, the middle and the later interval. The sedimentation rate of the

  7. Effects of Different Factors on Water Flow and Solute Transport Investigated by Time Domain Reflectometry in Sandy Clay Loam Field Soil.

    Science.gov (United States)

    Merdun, Hasan

    2012-09-01

    Factors affecting preferential flow and transport in the vadose zone need to be investigated by experiments and simulations to protect groundwater against surface applied chemicals. The objectives of this study were to investigate the effects of several factors (soil structure, initial soil water content (SWC), and application rate) and their interactions on the extent of preferential flow and transport in a sandy clay loam field soil using the time domain reflectometry (TDR) for measuring SWC and electrical conductivity (EC) in 12 treatments, modeling (by HYDRUS-1D and VS2DTI) the measured SWC and EC, and conducting statistical tests for comparing the means of the measured and modeled SWC and EC and solute transport parameters (pore water velocity and dispersion coefficient) obtained by inversely fitting in the CXTFIT program. The study results showed that the applied solution moved faster in the undisturbed, wet initial SWC, and higher application rate experimental conditions than in the disturbed, dry initial SWC, and lower application rate, respectively, based on the analysis of the changes in TDR measured SWC and EC with depth at 1, 2, 5, and 15 h of the experiments. However, the effects of interactive factors or treatments on water flow and solute transport were not clear enough. The modeling results showed that HYDRUS-1D was better than VS2DTI in the estimation of EC and especially SWC, but overall the models had relatively low performances in the simulations. Statistical test results also showed that the treatments had different flow and transport characteristics because they were divided into different groups in terms of the means of SWC and EC and solute transport parameters. These results suggest that similar experiments with more distinct interactions and modeling studies with different approaches need to be considered for better understanding the complex flow and transport processes in the vadose zone. PMID:23002311

  8. Automatic Water Sensor Window Opening System

    KAUST Repository

    Percher, Michael

    2013-12-05

    A system can automatically open at least one window of a vehicle when the vehicle is being submerged in water. The system can include a water collector and a water sensor, and when the water sensor detects water in the water collector, at least one window of the vehicle opens.

  9. Physicochemical reactivity in clay-rich materials: tools for safety assessment

    International Nuclear Information System (INIS)

    Natural or engineered clay-rich materials are ubiquitous when it comes to achieving sequestration of acid gas, confinement of pollutants or high level radioactive waste (HLRW), and trapping hydrocarbon oil and gas in geological settings. The sequestration, confinement, and trapping functions rely on properties such as low permeability, high sorption and ion exchange capacity, and, in some cases, on swelling abilities. Clay-rich materials contain specific clay minerals possessing these properties due to the small size and high tortuosity of the pores as well as the very high specific surface area and the surface charge of these minerals (especially smectites). For performance and safety purposes, the persistence of this initial sealing function has to be ensured over time, as the clay minerals of interest and the foreign anthropogenic materials (concrete, steel, and other clay materials in situ) will undergo physicochemical interactions and may lead to irreversible transformations. The clay minerals will also be subjected to perturbations due to the heat release of waste packages in the case of HLRW repository, and liquid water and vapour transfers. To tackle the complexity of these phenomena, we combine multi-scale and multi-technique characterisation (middle and far Fourier transform infrared, X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM)) on samples coming from laboratory experiments and natural analogues, and integrate the results through reactive transport modelling. As an example, the characterisation methodology is used to establish the illitisation of clay-stones due to a basaltic dyke intrusion. The approach is compared with classical ones and the application to diagenetic clay sequences for petroleum exploration is discussed. We also explore the high sensitivity of smectic (gel phase)/smectite properties as a function of water content/composition and temperature by investigating the interactions between

  10. Clay smear: Review of mechanisms and applications

    Science.gov (United States)

    Vrolijk, Peter J.; Urai, Janos L.; Kettermann, Michael

    2016-05-01

    Clay smear is a collection of fault processes and resulting fault structures that form when normal faults deform layered sedimentary sections. These elusive structures have attracted deep interest from researchers interested in subsurface fluid flow, particularly in the oil and gas industry. In the four decades since the association between clay-smear structures and oil and gas accumulations was introduced, there has been extensive research into the fault processes that create clay smear and the resulting effects of that clay smear on fluid flow. We undertake a critical review of the literature associated with outcrop studies, laboratory and numerical modeling, and subsurface field studies of clay smear and propose a comprehensive summary that encompasses all of these elements. Important fault processes that contribute to clay smear are defined in the context of the ratio of rock strength and in situ effective stresses, the geometric evolution of fault systems, and the composition of the faulted section. We find that although there has been progress in all avenues pursued, progress has been uneven, and the processes that disrupt clay smears are mostly overlooked. We highlight those research areas that we think will yield the greatest benefit and suggest that taking these emerging results within a more process-based framework presented here will lead to a new generation of clay smear models.

  11. Kaolinitic clay-based grouting demonstration

    International Nuclear Information System (INIS)

    An innovative Kaolinitic Clay-Based Grouting Demonstration was performed under the Mine Waste Technology Program (MWTP), funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by the EPA and the U.S. Department of Energy (DOE). The objective of the technology was to demonstrate the effectiveness of kaolinitic clay-based grouting in reducing/eliminating infiltration of surface and shallow groundwater through fractured bedrock into underground mine workings. In 1993, the Mike Horse Mine was selected as a demonstration site for the field implementation and evaluation of the grouting technology. The mine portal discharge ranged between 114 to 454 liters per minute (30 to 120 gpm) of water containing iron, zinc, manganese, and cadmium at levels exceeding the National Drinking Water Maximum Contaminant Levels. The grout formulation was designed by the developer Morrison Knudsen Corporation/Spetstamponazhgeologia (MK/STG), in May 1994. Grout injection was performed by Hayward Baker, Inc. under the directive of MSE Technology Applications, Inc. (MSE-TA) during fall of 1994. The grout was injected into directionally-drilled grout holes to form a grout curtain at the project site. Post grout observations suggest the grout was successful in reducing the infiltration of the surface and shallow groundwater from entering the underground mine workings. The proceeding paper describes the demonstration and technology used to form the subsurface barrier in the fracture system

  12. A water-quality assessment of the Busseron Creek watershed, Sullivan, Vigo, Greene, and Clay Counties, Indiana

    Science.gov (United States)

    Eikenberry, Stephen E.

    1978-01-01

    Chemical quality of surface water in the 237-square mile Busseron Creek watershed, in Indiana, is significantly affected by drainage from coal mines and municipalities. Drainage from coal mines is primarily a problem of higher than normal dissolved-solids concentration, whereas, drainage from municipalities is generally a problem of bacteria and phytoplankton. Generally, the water is calcium bicarbonate type, except in streams affected by drainage from coal mines, where the water is a mixed calcium and magnesium sulfate type. Ranges of concentration (in milligrams per liter) of dissolved solids and of some of the chemical constituents dissolved in streams from September 1975 to July 1976 were: dissolved solids, from 104 to 2,610; iron, from 0.00 to 150; sulfate, from 14 to 1,900; chloride, from 3.3 to 130; nitrate (as nitroglen), from 0.01 to 5.3; phosphate (as phosphorus), from 0.1 to 1.7; and total organic carbon, from 2.4 to 60. Range of pH was from 2.7 to 9.6 Ranges of concentration of chlorinated hydrocarbons (in micrograms per kilogram) detected in bed material of streams were: aldrin, from 0.2 to 0.4; chlordane, from 0 to 13; DDE, from 0.0 to 0.3; dieldrin, from 0.0 to 9.8; and heptachlor epoxide, from 0 to 1.0. Streams draining municipalities had high populations of fecal coliform bacteria (as many as 46,000 colonies per 100 milliliter) and phytoplankton (as many as 190 ,000 cells per milliliter). Dissolved-oxygen concentration ranged from 2.8 to 15.0 milligrams per liter. 

  13. Clay Mineral: Radiological Characterization

    Science.gov (United States)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  14. Water Districts - MO 2010 Active Public Drinking Water Systems (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This point layer represents active public drinking water systems. Each public drinking water system's distribution or service area is represented by a single point.

  15. Inhibiting water evaporation of sand soil with clay modified by linear alklybezene sulfonates%十二烷基苯磺酸钠改性黏土抑制沙土水分蒸发

    Institute of Scientific and Technical Information of China (English)

    张增志; 渠永平; 王宏娟; 杜红梅

    2014-01-01

    针对荒漠化地区生态恢复中沙土有效水分涵养难的问题,采用十二烷基苯磺酸钠(linear alklybezene sulfonates,LAS)与黏土复合制备土基改性材料。研究了材料在模拟沙漠气候条件下的保水性能,并测试材料老化后抗压强度损失率和质量损失率以及其保水性能的变化。采用扫描电子显微镜、傅里叶红外光谱分析、X 射线衍射分析、热重分析对材料保水机理进行研究。结果表明,土基改性材料保水性能良好,改性后黏土的片层结构和化学成分没有明显变化,通过LAS亲水端与黏土中结合水的相互作用,将松散的黏土胶结起来,LAS中憎水端相互连接形成憎水网络,从而在地表形成透气保水的固结层来有效降低水分蒸发。模拟沙漠气候条件下的植草试验表明当 LAS 和黏土的质量比为2∶1时,土基改性材料保水透气性能较佳,草籽发芽率从对照组的8%提高到43%。研究结果为制备新型土基固沙植草材料提供参考。%Desertification is one of the most serious environment problems in the world. Three methods commonly used in desertification control are engineering, chemical and biological sand fixation. Aiming at available water conservation in desertification ecological restoration, the clay-based modified materials were prepared by clay and sodium dodecyl benzene sulphonate (LAS) composite. LAS (2, 4, 6 and 8 g) was individually dissolved into 15 g distilled water while strong stirring for 10 minutes. Then, 3 g bentonite was slowly added into the solutions under strong stirring. The slurry was sprinkled onto sand with a relative humidity of 40%. The samples were regarded as L1, L2, L3 and L4, respectively according to the different contents of LAS (2, 4, 6 and 8 g), and the original clay L was as control group. The water retention property was studied in simulated desertification climate and the materials were analyzed and characterized

  16. Evaluation by design of experiments of active clay specimens behavior in the presence of distilled water, saline solutions and cationic inhibitors; Avaliacao por analise estatistica experimental do comportamento de corpos de prova de argila aditivada na presenca de agua destilada, solucoes salinas e inibidores cationicos

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, Emanuella Layne Ferreira; Araujo, Bruno Alysson Barbosa Duarte; Borges, Mauricio Rodrigues; Garcia, Rosangela Balaban [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    During the drilling, in general, there are layers of clays which water absorption easily as smectites. In drilling with clays swelling when is applied water-base fluid there is necessary the use of the clay inhibitors to avoid the incorporation of the cutting to the drilling fluid. The most used chemical inhibitors in drilling fluids are sodium and potassium chlorides. However, the cationic inhibitors have been used as alternative form to increase the inhibition power of the drilling fluids. In this work was evaluated the behaviour of the activated clay test bodies in the presence of distilled water, aqueous solution potassium chlorides, and cationic inhibitors. The solutions were submitted at Capillary Suction Timer tests to evaluation the capacity of the water retention in activated clay samples. At the interpretation of the results was used Design of Experiments (DOE) by Response Surface Methodology (RSM), using Umetrics MODDE 7.0{sup TM} programme. It was observed that the clay samples when in contact with the solutions presented lower water retention than in the presence of distilled water only. This result indicates that the clay was inhibited. (author)

  17. Metal corrosion and argillite transformation at the water-saturated, high-temperature iron-clay interface: A microscopic-scale study

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, Michel L. [Department of Physics and Chemistry, CEA - Laboratory for the Reactivity of Surfaces and Interfaces, DPC/SCP/LRSI, CEN Saclay, Bat. 391, F-91191 Gif-sur-Yvette Cedex (France); UMR 8587 ' LAMBE' , Universite d' Evry-Val d' Essonne, 91 025 Evry (France)], E-mail: Michel.Schlegel@cea.fr; Bataillon, Christian [CEA - Laboratory for the Study of Aqueous Corrosion, DPC/SCCME/LECA, CEN Saclay, Bat. 458, F-91191 Gif-sur-Yvette Cedex (France); Benhamida, Keltoum; Blanc, Cecile; Menut, Denis; Lacour, Jean-Luc [Department of Physics and Chemistry, CEA - Laboratory for the Reactivity of Surfaces and Interfaces, DPC/SCP/LRSI, CEN Saclay, Bat. 391, F-91191 Gif-sur-Yvette Cedex (France)

    2008-09-15

    In this study, microscopic and spectroscopic techniques (scanning electron microscopy coupled with energy-dispersive X-ray analysis, Raman microspectroscopy, micro X-ray fluorescence spectroscopy, micro X-ray fine structure adsorption spectroscopy, and micro laser-induced breakdown spectroscopy) were combined to decipher the chemical and mineralogical properties of a saturated Fe-clay interface reacted at 90 deg. C and 50 bar for 8 months. The results collectively confirm the presence of a corrosion layer and a clay transformation layer. The corrosion layer is made of a magnetite-containing internal sublayer and a Fe-phyllosilicate external sublayer enriched in Na, with traces of goethite presumably resulting from sample reaction with air. The clay transformation layer is made of predominantly Ca-rich siderite (FeCO{sub 3}). It is depleted in Al and K, suggesting dissolution of rock-forming minerals. The corroded thickness determined from the amount of Fe in corrosion and transformation layers and assuming zero porosity equals 19 {+-} 9 {mu}m. These data indicate that the interfacial clay was transformed by dissolution of calcite and clay minerals and precipitation of siderite close to the original surface. Silica released upon clay dissolution diffused into the corrosion layer and coprecipitated with oxidized Fe to form Fe-phyllosilicate.

  18. Study of adsorption of zinc in clay smectite type Bofe in system of finite bath; Estudo da adsorcao de zinco na argila esmectita do tipo Bofe em sistema de banho finito

    Energy Technology Data Exchange (ETDEWEB)

    Souza, R.S.; Mota, J.D.; Lima, W.S.; Rodrigues, M.G.F., E-mail: rocheliachel@hotmail.com, E-mail: meiry@deq.ufcg.edu.br [Universidade Federal de Campina Grande (LABNOV//LABGER/UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica. Lab. de Desenvolvimento de Novos Materiais e Lab. de Gestao Ambiental e Tratamento de Residuos

    2012-07-01

    Clays are demonstrably excellent adsorbents, both for their physical and chemical characteristics and the wide coverage and low cost. Among the various groups of clay minerals, the smectite are noted for having large surface areas. The initial objective of this study was to characterize the clay Bofe through the techniques of X-Ray Diffraction (XRD), X-Ray Spectrometry by Energy Dispersive (EDX) and nitrogen adsorption (BET). To evaluate the adsorption of metal ions zinc (synthetic sewage), we used a system in finite bath, following a factorial design 2{sup 2}, taking as input variables: pH and initial concentrations of zinc (Zn2 +) and output variables: percentage removal and removal capacity. The characterization results showed that Bofe clay belongs to the family of smectite and therefore has great potential for adsorption. (author)

  19. Effect of humic acid on pyrene removal from water by polycation-clay mineral composites and activated carbon.

    Science.gov (United States)

    Radian, Adi; Mishael, Yael

    2012-06-01

    Pyrene removal by polycation-montmorillonite (MMT) composites and granulated activated carbon (GAC) in the presence of humic acid (HA) was examined. Pyrene, HA, and sorbent interactions were characterized by FTIR, fluorescence and zeta measurements, adsorption, and column filtration experiments. Pyrene binding coefficients to the macromolecules were in the order of PVPcoS (poly-4-vinylpiridine-co-styrene) > HA > PDADMAC (poly diallyl-dimethyl-ammonium-chloride), correlating to pyrene-macromolecules compatibility. Electrostatic interactions explained the high adsorption of HA to both composites (∼100%), whereas HA adsorption by GAC was low. Pyrene removal by the composites, unlike GAC, was enhanced in the presence of HA; removal by PDADMAC-MMT increased from ∼50 (k(d) = 2.2 × 10(3) kg/L) to ∼70% (k(d) = 2.4 × 10(3) kg/L) in the presence of HA. This improvement was attributed to the adsorption of pyrene-HA complexes. PVPcoS-MMT was most efficient in removing pyrene (k(d) = 1.1 × 10(4) kg/L, >95% removal) which was explained in terms of specific π donor-π acceptor interactions. Pyrene uptake by column filters of GAC reached ∼50% and decreased to ∼30% in the presence of HA. Pyrene removal by the PVPcoS-MMT filter was significantly higher (100-85% removal), exhibiting only a small decrease in the presence of HA. The utilization of HA as an enhancing agent in pollutant removal is novel and of major importance in water treatment. PMID:22545663

  20. Drinking Water Temperature Modelling in Domestic Systems

    NARCIS (Netherlands)

    Moerman, A.; Blokker, M.; Vreeburg, J.; Van der Hoek, J.P.

    2014-01-01

    Domestic water supply systems are the final stage of the transport process to deliver potable water to the customers’ tap. Under the influence of temperature, residence time and pipe materials the drinking water quality can change while the water passes the domestic drinking water system. According

  1. Behavior of compacted clay-concrete interface

    Institute of Scientific and Technical Information of China (English)

    R.R. SHAKIR; Jungao ZHU

    2009-01-01

    Tests of interface between compacted clay and concrete were conducted systematically using interface simple shear test apparatus. The samples, having same dry density with different water content ratio, were prepared.Two types of concrete with different surface roughness, i.e., relatively smooth and relatively rough surface rough-ness, were also prepared. The main objectives of this paper are to show the effect of water content, normal stress and rough surface on the shear stress-shear displacement relationship of clay-concrete interface. The following were concluded in this study: 1) the interface shear sliding dominates the interface shear displacement behavior for both cases of relatively rough and smooth concrete surface except when the clay water content is greater than 16% for the case of rough concrete surface where the shear failure occurs in the body of the clay sample; 2) the results of interface shear strength obtained by direct shear test were different from that of simple shear test for the case of rough concrete surface; 3) two types of interface failure mechanism may change each other with different water content ratio; 4) the interface shear strength increases with increasing water content ratio especially for the case of clay-rough concrete surface interface.

  2. Mobile surface water filtration system

    Directory of Open Access Journals (Sweden)

    Aashish Vatsyayan

    2012-09-01

    Full Text Available To design a mobile system for surface water filtrationMethodology: the filtration of surface impurities begins with their retraction to concentrated thickness using non ionising surfactants, then isolation using surface tension property and sedimentation of impurities in process chamber using electrocoagulation. Result:following studies done to determine the rate of spreading of crude oil on water a method for retraction of spread crude oil to concentrated volumes is developed involving addition of non -ionising surfactants in contrast to use of dispersants. Electrocoagulation process involves multiple processes taking place to lead to depositionof impurities such as oil, grease, metals. Studies of experiments conducted reveals parameters necessary for design of electrocoagulation process chamber though a holistic approach towards system designing is still required. Propeller theory is used in determining the required design of propeller and the desired thrust, the overall structure will finally contribute in deciding the choice of propeller.

  3. Propulsion Systems in Water Tunnel

    Directory of Open Access Journals (Sweden)

    Nobuyuki Fujisawa

    1995-01-01

    agreement with the field experiment with prototype craft. Measurements are also made for the losses in the intake and the nozzle. The optimization study of the water jet systems is conducted by simulating the change of the nozzle outlet diameter with the variable nozzle arrangement. It is suggested that the nozzle outlet diameter should be decreased as the craft velocity increases to obtain an optimum propulsive efficiency in a wide range of craft velocity.

  4. Modeling crude oil droplet-sediment aggregation in nearshore waters.

    Science.gov (United States)

    Sterling, Michael C; Bonner, James S; Page, Cheryl A; Fuller, Christopher B; Ernest, Andrew N S; Autenrieth, Robin L

    2004-09-01

    This paper describes a modeling approach that simulates changes in particle size distribution and density due to aggregation by extending the Smoluchowski aggregation kinetic model to particles of different density. Batch flocculation studies were conducted for clay, colloidal silica, crude oil, clay-crude oil, and silica-crude oil systems. A parameter estimation algorithm was used to estimate homogeneous collision efficiencies (alphaHOMO) for single-particle-type systems and heterogeneous collision efficiencies (alphaHET) for two-particle-type systems. Homogeneous collision efficiency values (alphaHOMO) were greater for clay (0.7) and for crude oil (0.3) than for silica (0.01). Thus, clay and crude oil were classified as cohesive particles while silica was classified as noncohesive. Heterogeneous collision efficiencies were similar for oil-clay (0.4) and oil-silica (0.3) systems. Thus, crude oil increases the aggregation of noncohesive particles. Data from the calibrated aggregation model were used to estimate apparent first-order flocculation rates (K') for oil, clay, and silica and apparent second-order flocculation rates (K'') for oil and clay in oil-clay systems and for oil and silica in oil-silica systems. For oil or clay systems, aggregation Damköhler numbers ranged from 0.1 to 1.0, suggesting that droplet coalescence and clay aggregation can occur on the same time scales as oil resurfacing and clay settling, respectively. For mixed oil-clay systems, the relative time scales of clay settling and clay-oil aggregation were also within an order of magnitude. Thus, oil-clay aggregation should be considered when modeling crude oil transport in nearshore waters. PMID:15461172

  5. Clay membrane made of natural high plasticity clay:

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1999-01-01

    into account advective ion transport as well as diffusion. Clay prospecting for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island of Lolland. The natural clay contains 60-75% smectite, dominantly as a sodium...

  6. EEC Round Robin test on the repository system simulation - clay option. Final report EEC research contract No. Fl 1W-0116-l

    Energy Technology Data Exchange (ETDEWEB)

    Cantale, C.; Castelli, S.; Donato, A.; Traverso, D.M.

    1989-06-01

    The objective of the 'Reporting System Simulation Test (RSST) was to define a test method for the evaluation of waste performances in various geological disposal scenarios, with the possibility to simulate various additional materials, like canister, backfilling, overpack and host rock. The test procedure for the clay-option needed to be developed, especially with reference to the solution preparation and Eh (redox potential) measurements. The necessity to work in an argon atmosphere glove box brings in some operational complications, mainly in the case of the Eh measurement, filtering and final volume determination. The reproducibility of the experimental data does not seem to be particularly good, probably due to the difficulties in standardizing the experimental procedure. An effort should be done to improve these aspects. The tightness of the container and the physical stability of the rock/backfill/grill with pins/synthetic interstitial claywater system are excellent. The leaching data reveal that the clay contribution to the final ionic concentration of the solution is not negligible and should be better evaluated. The overall data-set shows that the glass leach rate, as expressed by Boron mass loss, decreases with time.

  7. Permeability Features of Water-Resistant Clay Layer in Northern Shaanxi Province While Shallowly Buried Coal Mining%陕北浅埋煤层开采隔水土层渗透性变化特征

    Institute of Scientific and Technical Information of China (English)

    李涛; 李文平; 常金源; 都平平; 高颖

    2011-01-01

    In order to evaluate the effect of exploiting shallowly buried coal on the ground water and surface water in Shennan Mining Area of northern Shaanxi, we studied the water-resisting degrees of the key aquifuges in overlying soil strata under mining influence. Based on the geologic investigation in Shennan Mining Area, the results of water pressure tests, and the permeability coefficient of clays in Lishi and Bode Ground which are determined by medium-pressured triaxial servo with the process of clay loading and unloading, we proposed the effect of shallowly buried coal mining on the permeability coefficient of the clays. The results show that the shallowly buried coal mining results in thin bedrock roof falling completely, and the destabilization of clay strata results in a change of permeability coefficient of the clays with several orders in the connected fissures area. However, in the pull-apart area, the ground fissures make the permeability coefficient of clay in Lishi Ground largen. With the increase of pressure, the permeability coefficient of clay in Bode Ground becomes smaller, resulting in plastic deformation of the clay, giving a basis for calculating the phreatic level which determinates the possibility of water preserving for exploiting the shallowly buried coal seams.%为评价陕北神南矿区浅埋煤层开采对地下水及地表水的影响,对煤层上覆关键隔水土层的采动隔水性进行研究.在进行了神南矿区野外地质调查的基础上,采用中压三轴伺服仪测定神南矿区离石组黄土及保德组红土在三轴加载及卸载过程中的渗透系数,并结合采前、采后现场压水试验成果研究了浅埋煤层开采前后关键隔水黏土层渗透系数变化特征.试验结果表明:浅埋煤层开采引起薄层基岩整体切落,在贯通裂隙发育区上覆隔水土层失稳表现为渗透系数几个数量级的巨大增加;而在拉张区黏土层上部的离石黄土受地面裂缝影响渗透性

  8. Validation of glass dissolution and Si diffusion parameters with a combined glass dissolution-diffusion experiment in Boom Clay

    International Nuclear Information System (INIS)

    Existing knowledge on glass dissolution and silica diffusion in Boom Clay is validated by experiments where both phenomena could be studied simultaneously. SON68 glass coupons, doped with radioactive 32Si, were sandwiched between two cores of fresh humid Boom Clay and heated to 30 deg. C. At the end of the experiment, the system was dismantled, the mass loss of the glass coupon was measured, and the clay core was sliced to determine the diffusion profile of the 32Si dissolved from the glass. These data were completed with analyses of the clay water and surface analyses for analogous tests with undoped glass. The results are interpreted by assuming congruent glass dissolution at a constant rate, with a glass silica saturation concentration between 14 and 20 mg/l, a forward glass dissolution rate (at zero silica concentration) of 0.028 g.m-2day-1, an apparent silica diffusion coefficient in the clay of 1.4 10-12 m2sec-1, and a distribution coefficient for silica on Boom Clay between 0.010 and 0.075 m3kg-1. These parameter values are close to the range found in literature. It was not necessary to consider diffusion through the gel, precipitation or detailed geochemical reactions. The modeling exercise shows that the existing knowledge about the subsystems glass and clay can successfully be integrated to describe the coupled processes in the whole system. (author)

  9. A minimalistic microbial food web in an excavated deep subsurface clay rock.

    Science.gov (United States)

    Bagnoud, Alexandre; de Bruijn, Ino; Andersson, Anders F; Diomidis, Nikitas; Leupin, Olivier X; Schwyn, Bernhard; Bernier-Latmani, Rizlan

    2016-01-01

    Clay rocks are being considered for radioactive waste disposal, but relatively little is known about the impact of microbes on the long-term safety of geological repositories. Thus, a more complete understanding of microbial community structure and function in these environments would provide further detail for the evaluation of the safety of geological disposal of radioactive waste in clay rocks. It would also provide a unique glimpse into a poorly studied deep subsurface microbial ecosystem. Previous studies concluded that microorganisms were present in pristine Opalinus Clay, but inactive. In this work, we describe the microbial community and assess the metabolic activities taking place within borehole water. Metagenomic sequencing and genome-binning of a porewater sample containing suspended clay particles revealed a remarkably simple heterotrophic microbial community, fueled by sedimentary organic carbon, mainly composed of two organisms: a Pseudomonas sp. fermenting bacterium growing on organic macromolecules and releasing organic acids and H2, and a sulfate-reducing Peptococcaceae able to oxidize organic molecules to CO(2). In Opalinus Clay, this microbial system likely thrives where pore space allows it. In a repository, this may occur where the clay rock has been locally damaged by excavation or in engineered backfills. PMID:26542073

  10. A minimalistic microbial food web in an excavated deep subsurface clay rock.

    Science.gov (United States)

    Bagnoud, Alexandre; de Bruijn, Ino; Andersson, Anders F; Diomidis, Nikitas; Leupin, Olivier X; Schwyn, Bernhard; Bernier-Latmani, Rizlan

    2016-01-01

    Clay rocks are being considered for radioactive waste disposal, but relatively little is known about the impact of microbes on the long-term safety of geological repositories. Thus, a more complete understanding of microbial community structure and function in these environments would provide further detail for the evaluation of the safety of geological disposal of radioactive waste in clay rocks. It would also provide a unique glimpse into a poorly studied deep subsurface microbial ecosystem. Previous studies concluded that microorganisms were present in pristine Opalinus Clay, but inactive. In this work, we describe the microbial community and assess the metabolic activities taking place within borehole water. Metagenomic sequencing and genome-binning of a porewater sample containing suspended clay particles revealed a remarkably simple heterotrophic microbial community, fueled by sedimentary organic carbon, mainly composed of two organisms: a Pseudomonas sp. fermenting bacterium growing on organic macromolecules and releasing organic acids and H2, and a sulfate-reducing Peptococcaceae able to oxidize organic molecules to CO(2). In Opalinus Clay, this microbial system likely thrives where pore space allows it. In a repository, this may occur where the clay rock has been locally damaged by excavation or in engineered backfills.

  11. Soil Water Repellency of Sands and Clay as Affected by Particle Size%砂土和黏土的颗粒差异对土壤斥水性的影响

    Institute of Scientific and Technical Information of China (English)

    杨松; 吴珺华; 董红艳; 张燕明

    2016-01-01

    斥水性土壤广泛存在于自然界中,并且对土壤环境和作物生长等有重要影响。建立理想化的土壤颗粒模型对砂土和黏土的斥水特性进行计算分析。结果表明:当接触角很小时,砂土中不存在斥水现象。随着接触角的增大,砂土斥水性与含水率密切相关,砂土的密实度对其斥水性也有重要影响,当砂土比较密实时,土壤的“亲水”与“斥水”特性对含水率特别敏感,随着含水率的变化,砂土可能由亲水性较好的土壤转变为斥水性土壤;当砂土比较松散时,土壤颗粒的斥水性对含水率并不敏感。当黏土接触角略小于90°且湿润半径b也较小时,黏土也存在斥水现象。如果黏土颗粒的接触角较小或接触角小于90°且湿润半径b较大,黏土总是亲水的。黏土含水率较大时,斥水特性由土壤颗粒的接触角决定。%Water-repellent soils,existing widely in nature,have some important effects on soil environment and crop growth. In order to analyze water repellency of sand and clay,models of sand and clay different in particle size were built. Results showed that no phenomenon of water repellency was found in sand soil when the contact angle of water with sand was small. Water repellency of sand soil was closely related to soil water content when the sand-water contact angle was big. Compactness of the soil was another important factor affecting soil water repellency. When the sand soil was highly compacted,whether the soil was hydrophilic or hydrophobic was very sensitive to water content,and it might switch from one state to another with changing soil water content. When the sand soil was quite loose,it was no longer sensitive to soil water content. In clay soil with soil-water contact angle being slightly less than 90°and wetting radius b being small,the phenomenon of water repellency was observed. But when the clay soil was much smaller than 90°in soil-water and

  12. California community water systems inventory dataset, 2010

    Data.gov (United States)

    California Environmental Health Tracking Program — This data set contains information about all Community Water Systems in California. Data are derived from California Office of Drinking Water (ODW) Water Quality...

  13. Processes of cation migration in clay-rocks: Final Scientific Report of the CatClay European Project

    International Nuclear Information System (INIS)

    In the framework of the feasibility studies on the radioactive waste disposal in deep argillaceous formations, it is now well established that the transport properties of solutes in clay rocks, i.e. parameter values for Fick's law, are mainly governed by the negatively charged clay mineral surface. While a good understanding of the diffusive behaviour of non-reactive anionic and neutral species is now achieved, much effort has to be placed on improving understanding of coupled sorption/diffusion phenomena for sorbing cations. Indeed, several cations known to form highly stable surface complexes with sites on mineral surfaces migrate more deeply into clay rock than expected. Therefore, the overall objective of the EC CatClay project is to address this issue, using a 'bottom-up' approach, in which simpler, analogous systems (here a compacted clay, 'pure' illite) are experimentally studied and modelled, and then the transferability of these results to more complex materials, i.e. the clay rocks under consideration in France, Switzerland and Belgium for hosting radioactive waste disposal facilities, is verified. The cations of interest were chosen for covering a representative range of cations families: from a moderately sorbing cation, the strontium, to three strongly sorbing cations, Co(II), Zn(II) and Eu(III). For the 4 years of this project, much effort was devoted to developing and applying specific experimental methods needed for acquiring the high precision, reliable data needed to test the alternative hypotheses represented by different conceptual-numerical models. The enhanced diffusion of the sorbing cations of interest was confirmed both in the simpler analogous illite system for Sr2+, Co(II) and Zn(II), but also in the natural clay rocks, except for Eu(III). First modelling approach including diffusion in the diffuse double layer (DDL) promisingly succeeded in reproducing the experimental data under the various conditions both in

  14. Carbon and Water Resource Management for Water Distribution Systems

    OpenAIRE

    Hendrickson, Thomas Peter

    2013-01-01

    Water distribution systems (WDS) worldwide face increasing challenges as population growth strains a limited water supply in many areas. In the United States, existing water infrastructure systems require significant investments to refurbish an aging stock of assets. Much of this investment is required in drinking water transmission and distribution, where a substantial amount of material and economic inputs are lost as a result of pipeline leaks. With growing worldwide concern for reducing e...

  15. Technetium migration in natural clays

    International Nuclear Information System (INIS)

    The present work was performed within the joint research project ''Retention of repository relevant radionuclides in argillaceous rocks and saline systems'' (contract no.: 02E10981), funded by the Federal Ministry for Economic Affairs and Energy (BMWi). The aim was to obtain first insights into the interaction of the long-lived fission product technetium and natural clay with regard to a repository for high-level nuclear waste. For this purpose Opalinus Clay from Mont Terri (northern Switzerland) was used as a reference material. The nuclide technetium-99 will contribute to the radiotoxicity of spent nuclear fuel for more than thousand years due to its long half-live. In case of a leakage of the storage vessels, the geochemistry of technetium is determined by its oxidation state, at which only the oxidation states +IV and +VII are relevant. Because of the high solubility and low affinity to sorption on surfaces of minerals, Tc(VII) is considered to be very mobile and thus the most hazardous species. The focuses of this study therefore are diffusion experiments with this mobile species and investigations of the effect of ferrous iron on the mobility and speciation of technetium.rnThe interaction of technetium and Opalinus Clay was studied in sorption and diffusion experiments varying several parameters (pH value, addition of reducing agents, effect of oxygen, diffusion pathways). In the course of this study spatially resolved investigations of the speciation have been performed on Opalinus Clay thin sections and bore cores for the first time. In addition to the speciation, further information regarding elemental distributions and crystalline phases near technetium enrichments were obtained. Supplementary investigations of powder samples allowed determining the molecular structure of technetium on the clay surface.rnBoth the combination of sorption experiments with spectroscopic investigations and the diffusion experiment exhibit a reduction of Tc

  16. Joint project. Retention of radionuclides relevant for final disposal in natural clay rock and saline systems. Subproject 2. Geochemical behavior and transport of radionuclides in saline systems in the presence of repository-relevant organics. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, Katja; Fritsch, Katharina; Lippold, Holger [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Ressource Ecology; and others

    2016-08-01

    retention at these minerals could be attributed to surface-mediated reduction of Tc(VII) to Tc(IV). An influence of ionic strength was not observed. The influence of ionic strength (up to 3 mol/kg) and background electrolyte (NaCl, CaCl{sub 2}, MgCl{sub 2}) on U(VI) sorption onto montmorillonite was studied. The U(VI) sorption is influenced by the background electrolyte, the influence of ionic strength is small. Surface complexation modeling was performed applying the 2SPNE SC/CE model. Surface complexation constants were determined for the NaCl and CaCl{sub 2} system and were extrapolated to zero ionic strength. Surface complexation in mixed electrolytes can be modeled applying surface complexation constants derived for pure electrolytes. The influence of citrate on U(VI) diffusion in Opalinus Clay was studied using Opalinus Clay pore water as background electrolyte. The diffusion parameter values obtained for the HTO through-diffusion and the U(VI) in-diffusion in the absence of citric acid were in agreement with literature data. In the presence of citric acid, U(VI) diffusion was significantly retarded, which was attributed to a change in speciation, probably U(VI) was reduced to U(IV). Larger-scale heterogeneous material effects on diffusive transport were investigated with PET. Diffusion parameters were derived by optimum fit of a FEM-model to the measurement. These parameters are in accordance with the results from 1D-through-diffusion experiments. Deviations from the simple transversal-isotropic behavior, which are identified as residuals from the model, are indications for heterogeneous transport on the mm-scale. PET measurements were also conducted in order to display the improvement of the EDZ with waterglass injections. These experiments enable to draw conclusions on the complex reactive transport process and thus an estimation of the achieved improvement of the barrier function. The image reconstruction procedure was largely improved, mainly with the aid of

  17. Electroporation System for Sterilizing Water

    Science.gov (United States)

    Schlager, Kenneth J.

    2005-01-01

    A prototype of an electroporation system for sterilizing wastewater or drinking water has been developed. In electroporation, applied electric fields cause transient and/or permanent changes in the porosities of living cells. Electroporation at lower field strengths can be exploited to increase the efficiency of chemical disinfection (as in chlorination). Electroporation at higher field strengths is capable of inactivating and even killing bacteria and other pathogens, without use of chemicals. Hence, electroporation is at least a partial alternative to chlorination. The transient changes that occur in micro-organisms at lower electric-field strengths include significantly increased uptake of ions and molecules. Such increased uptake makes it possible to achieve disinfection at lower doses of chemicals (e.g., chlorine or ozone) than would otherwise be needed. Lower doses translate to lower costs and reduced concentrations of such carcinogenic chemical byproducts as trichloromethane. Higher electric fields cause cell membranes to lose semipermeability and thereby become unable to function as selective osmotic barriers between the cells and the environment. This loss of function is the cause of the cell death at higher electric-field intensities. Experimental evidence does not indicate cell lysis but, rather, combined leaking of cell proteins out of the cells as well as invasion of foreign chemical compounds into the cells. The concept of electroporation is not new: it has been applied in molecular biology and genetic engineering for decades. However, the laboratory-scale electroporators used heretofore have been built around small (400-microliter) cuvettes, partly because the smallness facilitates the generation of electric fields of sufficient magnitude to cause electroporation. Moreover, most laboratory- scale electroporators have been designed for testing static water. In contrast, the treatment cell in the present system is much larger and features a flow

  18. Laboratory investigations of Mars - Chemical and spectroscopic characteristics of a suite of clays as Mars soil analogs

    Science.gov (United States)

    Banin, Amos; Carle, Glenn C.; Chang, Sherwood; Coyne, Lelia M.; Orenberg, James B.

    1988-01-01

    A model system of Mars soil analog materials (MSAMs) was prepared, and the properties of these clays, such as chemical composition, surface-ion composition, water adsorption isotherms, and reflectance spectra, were examined. The results of these studies, performed along with simulations of the Viking Labeled Release Experiement using MSAMs, indicate that surface iron and adsorbed water are important determinants of clay behavior, as evidenced by changes in reflectance, water absorption, and clay surface reactions. The paper discusses the relevance of these results to the two major questions raised by prior explorations of Mars: has there ever been abundant water on Mars, and why is the iron found in the Martian soil not readily seen in the reflectance spectra of the surface?

  19. The Effects of High Salinity Groundwater on the Performance of Clay Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David [Quintessa Ltd., Nottingham (United Kingdom)

    2005-07-01

    Potential changes in groundwater chemistry during the operational or post-closure periods of the Swedish repository for spent fuel could affect the performance of both the bentonite buffer and repository backfill. For example, the up-coning of saline groundwater could lead to decreased swelling pressures in both the bentonite buffer and tunnel backfills, and could also induce 'piping'. SKB is considering these issues as part of its 'SR-Can' safety assessment. This report reviews evidence for the behaviour of swelling clays in groundwaters of varying salinity with special relevance to the SKB programme. Smectite clays can absorb water into clay inter-layers with the most important parameters being: the surface density of charge of the clay; the charge and solvation behaviour of the inter-layer ions; and the electrolyte concentration or activity of water. Two categories of swelling are generally observed: innercrystalline swelling caused by the hydration of the exchangeable cations in the dry clay; and osmotic swelling, resulting from concentration gradients in ion concentrations between clay surfaces and pore water. Several models exist to interpret and predict the swelling behaviour of clays. SKB currently prefer an interpretation of clay swelling pressure where clay particles are viewed as 'macro-ions' and the entire clay-water system can be considered as a 'polyelectrolyte'. SKB use the term 'Donnan exclusion' to estimate the amount of introduced ions into the clay and hence the amount of reduced swelling pressure due to contact with a saline solution. Donnan exclusion is the process whereby the migration of anions through the narrow aqueous film surrounding clay platelets is restricted due to the repulsion by the negative charge of the clay platelets. SKB's experimental work shows that: There is an exponential relation between swelling pressure and mean basal interlamellar spacing of the clay. Ions from the

  20. Calculation of the debris flow concentration based on clay content

    Institute of Scientific and Technical Information of China (English)

    CHEN; Ningsheng; CUI; Peng; LIU; Zhonggang; WEI; Fangqiang

    2003-01-01

    The debris flow clay content has very tremendous influence on its concentration (γC). It is reported that the concentration can be calculated by applying the relative polynomial based on the clay content. Here one polynomial model and one logarithm model to calculate the concentration based on the clay content for both the ordinary debris flow and viscous debris flow are obtained. The result derives from the statistics and analysis of the relationship between the debris flow concentrations and clay content in 45 debris flow sites located in the southwest of China. The models can be applied for the concentration calculation to those debris flows that are impossible to observe. The models are available to calculate the debris flow concentration, the principles of which are in the clay content affecting on the debris flow formation, movement and suspending particle diameter. The mechanism of the relationship of the clay content and concentration is clear and reliable. The debris flow is usually of micro-viscous when the clay content is low (<3%), by analyzing the developing tendency on the basics of the relationship between the clay content and debris flow concentration. Indeed, the less the clay content, the less the concentration for most debris flows. The debris flow tends to become the water rock flow or the hyperconcentrated flow with the clay content decrease. Through statistics it is apt to transform the soil into the viscous debris flow when the clay content of ranges is in 3%-18%. Its concentration increases with the increasing of the clay content when the clay content is between 5% and 10%. But the value decreases with the increasing of the clay content when the clay content is between 10% and 18%. It is apt to transform the soil into the mudflow, when the clay content exceeds 18%. The concentration of the mudflow usually decreases with the increase of the clay content, and this developing tendency reverses to that of the micro-viscous debris flow. There is

  1. Water reactive hydrogen fuel cell power system

    Science.gov (United States)

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  2. Safety Problems of Small Water Supply Systems

    Directory of Open Access Journals (Sweden)

    Tchórzewska-Cieślak Barbara

    2016-07-01

    Full Text Available The paper presents issues related to risks associated with the operation of small water supply systems on the background of water consumer safety assessment made on the basis of risk analysis. Definition of water consumer safety loss as a risk associated with the water consumption of poor quality or water lack was proposed. For this purpose, a three-parameter matrix is implemented with the parameters of the probability of a representative accident scenario, the losses of the water consumers and their protection. Risk management, together with the implementation of protective barriers of small water supply system against threats is a fundamental condition for the continued operation of the system.

  3. Engineering property test of kaolin clay contaminated by diesel oil

    Institute of Scientific and Technical Information of China (English)

    刘志彬; 刘松玉; 蔡奕

    2015-01-01

    Engineering property of kaolin clay contaminated by diesel oil was studied through a series of laboratory experiments. Oil contents (mass fraction) of 4%, 8%, 12%, 16% and 20% were selected to represent different contamination degrees, and the soil specimens were manually prepared through mixing and static compaction method. Initial water content and dry density of the test kaolin clay were controlled at 10% and 1.58 g/cm3, respectively. Test results indicate that since part of the diesel oil will be released from soil by evaporation, the real water content should be derived through calibration of the quasi water content obtained by traditional test method. As contamination degree of the kaolin clay increases, both liquid limit and plastic limit decrease, but there’s only a slight increase for plasticity index. Swelling pressure of contaminated kaolin clay under confined condition will be lowered when oil-content gets higher. Unconfined compressive strength (UCS) of the oil-contaminated kaolin clay is influenced by not only oil content but also curing period. Increase of contamination degree will continually lower UCS of the kaolin clay specimen. In addition, electrical resistivity of the contaminated kaolin clay with given water content decreases with the increase of oil content. However, soil resistivity is in good relationship with oil content and UCS. Finally, oil content of 8% is found to be a critical value for engineering property of kaolin clay to transit from water-dominated towards oil-dominated characteristics.

  4. Soil-water characteristics and pore-size distribution of lateritic clay%红黏土的土水特性及其孔隙分布

    Institute of Scientific and Technical Information of China (English)

    孙德安; 高游; 刘文捷; 韦昌富; 张升

    2015-01-01

    The pressure plate method, filter paper method and vapor equilibrium technique with saturated salt solution and mercury intrusion porosimetry tests on Guilin lateritic clay are used to investigate the soil-water characteristics and pore-size distribution of undisturbed and compacted specimens in full suction range. The test results show that the undisturbed specimen has lower water content and saturation degree than the compacted one in the suction ranging from 0 kPa to 10 MPa because of the development of internal crack of undisturbed specimen with the increasing suction. When the suction is higher than 10 MPa, the soil-water characteristic curves (SWCC) coincide with each other. In the transition zone, the SWCCs of the undisturbed and compacted specimens are different from the typical ones. The undisturbed natural specimens exhibit a unimodal pore-size distribution, and the compacted ones usually have a double-porosity microstructure. The stability of shrinkage of the undisturbed natural specimen is larger than that of the compacted one. The compacted specimens with different dry densities also have the same pore-size distribution between particles, while the inter-aggregate pore distribution differ between the compacted specimens with different dry densities. It explains that when it is expressed by the relation between suction and water content, the SWCC is independent of dry density in the high suction range. When it is expressed by the relation between suction and saturation degree, the SWCC with high dry density is higher than that with the small one.%以桂林红黏土为研究对象,采用压力板法、滤纸法和饱和盐溶液蒸气平衡法3种方法研究在全吸力范围内原状样和压实样的土水特性,并结合压汞试验研究其孔隙分布。试验结果表明:当吸力约小于10 MPa时原状样的土水特征曲线略低于压实样,主要原因是原状样内部裂隙随吸力的增加而不断发展;当吸力约大于10

  5. Performance of polymeric films based thermoplastic starch and organophilic clay; Efeito da incorporacao de argila no desempenho de filmes de amido termoplastico/PEBD

    Energy Technology Data Exchange (ETDEWEB)

    Cipriano, P.B.; Costa, A.N.M.; Araujo, S.S.; Araujo, A.R.A.; Canedo, E.L.; Carvalho, L.H., E-mail: pamufcg@gmail.co [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The aim of this work was the development and investigation of the properties of flat films of LDPE/corn thermoplastic starch (TPS). A bentonite clay (Argel) was organophilized and characterized by XRD. This clay (1%) in both pristine and organophilic forms was added to the matrix (LDPE) and to LDPE/TPS systems with TPS contents varying from 5-20% w/w. The films manufactured (LDPE, LDPE/Clay, LDPE/TPS, LDPE/TPS/Clay) were characterized. Results indicate that water vapor permeability is dependent and increases with TPS content which was attributed to the higher affinity of water by TPS. TPS and Clay addition to LDPE led to significant changes in film properties with respect to the neat LDPE. In general,tensile and perforation forces increased with clay and TPS contents; the strength of thermo sealed films lowered with natural clay addition and increased with TPS and organoclay incorporation and, in general, dynamic friction coefficient decrease with organoclay and TPS addition. Best overall properties were obtained for the systems containing the organoclay and optimal properties were achieved for the 5%TPS10 LDPE1% ANO system. (author)

  6. Adsorption of dyes using different types of clay: a review

    Science.gov (United States)

    Adeyemo, Aderonke Ajibola; Adeoye, Idowu Olatunbosun; Bello, Olugbenga Solomon

    2015-09-01

    Increasing amount of dyes in the ecosystem particularly in wastewater has propelled the search for more efficient low-cost adsorbents. The effective use of the sorption properties (high surface area and surface chemistry, lack of toxicity and potential for ion exchange) of different clays as adsorbents for the removal of different type of dyes (basic, acidic, reactive) from water and wastewater as potential alternatives to activated carbons has recently received widespread attention because of the environmental-friendly nature of clay materials. Insights into the efficiencies of raw and modified/activated clay adsorbents and ways of improving their efficiencies to obtain better results are discussed. Acid-modified clay resulted in higher rate of dye adsorption and an increased surface area and porosity (49.05 mm2 and 53.4 %). Base-modified clay has lower adsorption capacities, while ZnCl2-modified clay had the least rate of adsorption with a surface area of 44.3 mm2 and porosity of 43.4 %. This review also explores the grey areas of the adsorption properties of the raw clays and the improved performance of activated/modified clay materials with particular reference to the effects of pH, temperature, initial dye concentration and adsorbent dosage on the adsorption capacities of the clays. Various challenges encountered in using clay materials are highlighted and a number of future prospects for the adsorbents are proposed.

  7. Effective Removal of Heavy Metals from Wastewater Using Modified Clay.

    Science.gov (United States)

    Song, Mun-Seon; Vijayarangamuthu, K; Han, EunJi; Jeon, Ki-Joon

    2016-05-01

    We report an economical and eco-friendly way to remove the heavy metal pollutant using modified clay. The modification of clay was done by calcining the natural clay from Kyushu region in Japan. Further, the removal efficiency for various pH and contact time was evaluated. The morphology of the clays was studied using the scanning electron microscopy (SEM). The structural and chemical analyses of modified clay were done by using X-ray diffraction (XRD), Raman spectroscopy, and Energy dispersion analysis (EDAX) to understand the properties related to the removal of heavy metal pollutant. Further, we studied the absorption efficiency of clay for various pH and contacting time using Ni polluted water. The modified clays show better removal efficiency for all pH with different saturation time. The adsorption follows pseudo-second order kinetics and the adsorption capacity of modified clay is 1.5 times larger than that of natural clay. The increase in the adsorption efficiency of modified clay was correlated to the increase in hematite phase along with increase in surface area due to surface morphological changes.

  8. Separation of components of a broad 1H-NMR composite signal by means of nutation experiments under low amplitude radiofrequency fields. Application to the water signal in synthetic clays; Developpement et mise en oeuvre d'une nouvelle methode fondee sur le phenomene de nutation pour la decomposition d'un signal composite de resonance magnetique nucleaire. Application au signal 1h de l'eau dans des argiles synthetiques

    Energy Technology Data Exchange (ETDEWEB)

    Trausch, G

    2006-11-15

    Nowadays, geologic nuclear waste storage is envisioned according to a multi-layer model which implies clays. The latter exhibit retention capacities and low permeability to water; that is why they are considered as a good candidate for engineered barriers to radioactive waste disposal. The present work here aims at studying transport phenomena which involve water molecules in three samples of synthetic clays (two of them exhibiting a Pake doublet) by means of Nuclear Magnetic Resonance (NMR). The first chapter describes structural properties of clays and presents the state-of-art of NMR and other experimental techniques used for such systems. The second chapter deals with the interpretation and the simulation of each conventional proton spectrum. These simulations allow us to evidence and to characterize a chemical exchange phenomenon. The third chapter is dedicated to original nutation experiments performed under low radiofrequency field in the case of broad NMR signal. It is shown that this type of NMR experiment can yield the number and the proportion of each species contributing to the whole signal. These results are exploited in the fourth chapter for processing relaxation and diffusion experiments. Finally, the diffusion coefficients obtained by NMR are divided by a factor 4 with respect to pure water while relaxation rates are two orders of magnitude greater. (author)

  9. Final Report (BMWi Project No.: 02 E 10971): Joint project: Retention of radionuclides relevant for final disposal in natural clay rock and saline systems - Subproject 2: Geochemical behavior and transport of radionuclides in saline systems in the prese

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, Katja [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Fritsch, Katharina [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Lippold, Holger [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Poetsch, Maria [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Kulenkampff, Johannes [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Lippmann-Pipke, Johanna [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Jordan, Norbert [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Joseph, Claudia [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Moll, Henry [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Cherkouk, Andrea [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology; Bader, Miriam [Helmholtz-Zentrum Dresden, (Germany). Inst. of Resource Ecology

    2016-02-29

    The objective of this project was to study the influence of increased salinities on interaction processes in the system radionuclide – organics – clay – aquifer. For this, complexation, redox, sorption, and diffusion studies were performed under variation of the ionic strength (up to 4 mol kg-1) and the background electrolyte (NaCl, CaCl2, MgCl2).

  10. The effect of clay minerals on diasterane/sterane ratios

    Science.gov (United States)

    van Kaam-Peters, Heidy M. E.; Köster, Jürgen; van der Gaast, Sjierk J.; Dekker, Marlèn; de Leeuw, Jan W.; Sinninghe Damsté, Jaap S.

    1998-09-01

    To examine the effect of clay minerals on diasterane/sterane ratios, the mineral compositions of three sample sets of sedimentary rocks displaying a wide range of diasterane/sterane ratios were analysed quantitatively. Diasterane/sterane ratios do not to correlate with clay content but depend on the amount of clay relative to the amount of organic matter (clay/TOC ratios). This correlation may explain the high diasterane/sterane ratios in crude oils and extracts derived from certain carbonate source rocks. Based on the concentrations of regular and rearranged steroids in the sample sets, it is proposed that diasterenes are partly reduced to diasteranes and partly degraded during diagenesis in a ratio largely determined by the availability of clay minerals. It is suggested that the hydrogen atoms required for reduction of the diasterenes originate from the water in the interlayers of clay minerals.

  11. Clay Minerals as Solid Acids and Their Catalytic Properties.

    Science.gov (United States)

    Helsen, J.

    1982-01-01

    Discusses catalytic properties of clays, attributed to acidity of the clay surface. The formation of carbonium ions on montmorillonite is used as a demonstration of the presence of surface acidity, the enhanced dissociation of water molecules when polarized by cations, and the way the surface can interact with organic substances. (Author/JN)

  12. Dredging Processes I: The Cutting of Sand, Clay & Rock - Theory

    NARCIS (Netherlands)

    Miedema, S.A.

    2013-01-01

    This book gives an overview of cutting theories. It starts with a generic model, which is valid for all types of soil (sand, clay and rock) after which the specifics of dry sand, water saturated sand, clay, rock and hyperbaric rock are covered. For each soil type small blade angles and large blade a

  13. 土基改性固沙植草材料抑制地表水分蒸发%Inhibiting water evaporation of ground surface by clay-based sand-fixing and grass-planting materials

    Institute of Scientific and Technical Information of China (English)

    王博涛; 张增志

    2012-01-01

    针对固沙生态恢复中面临的有效水分涵养难题,采用Span-80乳化木蜡改性黏土制备了固沙植草喷膜材料.研究了材料在模拟荒漠化环境气候中的保水性能,采用紫外-可见光分光光度分析、扫描电子显微镜分析、傅里叶红外光谱分析、X射线衍射分析、热重分析等手段对制备的材料进行分析和表征.结果表明:该固沙植草喷膜材料具有良好的保水性能,改性后黏土的层间结构未发生变化,木蜡均匀涂覆在土壤颗粒表面,颗粒间的孔隙由亲水孔转变为憎水孔从而抑制了水分的蒸发;植草试验表明当植草喷膜材料中木蜡、黏土、Span-80 3种组分质量比为1:6:24时固沙植草材料既能很好地抑制水分蒸发又能保持较好的透气性,草籽发芽率从对照组的5%提高至45%.%According to the problem of available water conservation in sand consolidation, the sand-fixing and grass-planting materials were prepared with clay modified by emulsifying vegetable waxes and octylphenol polyoxyethylene ether (Span-80). The water retention property was studied in simulated desertification environmental climate and the materials were characterized by means of UV-Vis, SEM, FTIR, XRD and TA measurements. The results showed that the materials had excellent water retention properties, which owning to that vegetable waxes adhering evenly to clay particle surfaces, making the clay pores changing from hydrophilic to hydrophobic and so inhibiting the water evaporation. Grass-planting experiment showed that with reasonable mass ratio of vegetable waxes, clay and surfactant at 1:6:24, the materials not only inhibited water evaporation but also maintained sound air permeability so that the germination rate of grass seed was significantly improved from 5% to 45%.

  14. Modernity and putty-clay

    Science.gov (United States)

    Ganesh, Trichur Kailas

    This dissertation addresses issues arising out of the problems of capital accumulation, productivity growth and 'putty-clay' technology. The concept of economic modernity occupies a central place in the subject-matter studied here in that it expresses both the incessant drive for newness that characterizes economic reality and the persistence of dated techniques that successfully resist replacement. This study examines the way in which an expansive development-theoretic 'putty-clay' framework may be employed to explain the historical processes behind both the avalanche of newness (innovations) and the conservatism of technology in the U.S. economy. The guiding link is the fixity of investments in physical capital equipment over time and space. The dilemma of fixed capital is studied in the context of the constant entrepreneurial search for flexibility and liquidity. The thesis advanced is that a development (Entwicklung)-theoretic 'putty-clay' conceptualization of the economic system adequately addresses the recurring problems of fixity, flexibility, and liquidity, and thereby permits important insights into the enigma surrounding the persistent productivity growth slowdown and 'stagflation' of the late sixties and seventies and the related phenomena of physical 'capital obsolescence' and the financial or 'speculative explosions' of our times. The notion of 'putty-clay' used here is an innovative one in that it departs from the growth-theoretic literature to re-appear as a Schumpeterian theory of modernity modified by a Veblenite view of an economic system directed by the exigencies of the 'machine-process'. The empirical aptitude of a macroeconomic 'putty-clay' model to explain capital obsolescence mediated by the energy 'crises' (supply shocks) of the seventies and eighties is examined in a separate chapter with results that differ markedly from the standard (Berndt and Wood) conclusions for the U.S. economy. The final chapter in the dissertation reverts to the

  15. Modification and characterization of montmorillonite clay for the extraction of zearalenone

    Science.gov (United States)

    Hue, Kerri-Ann Alicia

    Mycotoxins are secondary metabolites of organisms belonging to the fungus kingdom. The cost associated with mycotoxin contamination in the USA and Canada is approximately US $5 billion. Zearalenone (ZEN), a resorcylic acid lactone, is produced by various members of the genus Fusarium . These fungi often colonize a variety of foods and feedstuffs including, corn, sorghum, wheat, oats, barley, and other cereal grains. This metabolite has estrogenic effects in farm animals with pigs being the most sensitive. ZEN induces hyperestrogenism and can cause infertility, reduced sex drive, fetal mummification, and abortions. Clays have successfully been used in the animal feed industry as an adsorbent and binders for certain small, water soluble mycotoxins. These mycotoxins are attracted to the electrical imbalance between the layers of the clays caused by isomorphic substitution of structural atoms. The mycotoxins are sequestered in the clay layers and pass harmlessly through the animal. However, ZEN is water insoluble and is not extracted easily with aluminosilicate clays. Therefore the modification of hydrated sodium calcium aluminosilicate (HSCAS) clays with organic cations has been proposed to render the clays hydrophobic and increase the ZEN binding capacity. The goal of this study was to develop a safe and cost effective organophilic material able to bind and extract zearalenone, to investigate the factors most important to extraction, and to investigate the fundamental properties between the clay-surfactant-mycotoxin systems that lead to extraction. The clay was modified by cation exchange reactions with tricaprylmethylammonium (TCMA) chloride and generic corn oil. The organophilic clays were then characterized using XRD, FTIR, and TGA analytical techniques. These techniques were used to determine the change in fundamental clay properties that would lead to the extraction of ZEN. Desorption studies were performed to determine any increase in toxicity that might be

  16. Colloidal behavior of clay in whiteware suspensions

    Science.gov (United States)

    Rossington, Katherine Rose

    2000-10-01

    This research investigated the colloidal behavior of kaolinitic clay in aqueous suspensions. The foundation of most current clay suspension behavior is based on early studies conducted prior to the application of colloidal concepts in ceramic systems and also when many of the colloidal theories were being developed. Technological advances in colloid science and the application of the theories greatly enhance the interpretation of the clay suspension behavior. Kaolinitic clay is the primary component responsible for the colloidal behavior of in traditional ceramics because the clay accounts for of the total surface area and active charge sites. The impact of cations and anions on colloidal behavior, specifically the dispersion and coagulation, of a whiteware suspension was examined using rheology and electrophoretic mobility measurements. The results indicate the cations are responsible for coagulating the suspension, including sodium, which has been labeled both a dispersant and a coagulant. The anionic species are responsible for dispersing the clay suspension, but zeta potential is an inaccurate measure of suspension stability. The influence of chemistry changes via cation and anion additions observed in suspensions are also detected in plastic bodies. The plasticity measured by the cohesion stress decreases with increasing cation concentration. It is suggested that the magnitude of the cohesion stress directly influences the formability and stress gradients established during drying.

  17. Formation of hydrocarbons from acid-Clay suspensions by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Castaneda, J.; Negron-Mendoza, A.; Ramos-Bernal, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A. P. 70-543, 04510 Mexico (Mexico)

    2013-07-03

    The adsorption of certain organic compounds by clays gives rise to the transformation of the adsorbate through the action of the clays. This phenomenon can be enhanced using ionizing radiation. In this context, these kinds of reactions play an important role in many natural and industrial processes. For example, in oil and gas exploration, the source and trap of petroleum hydrocarbons is frequently clay-rich rocks. Clay-water-based muds are also seen as environmentally friendly alternatives to toxic oil-based fluids. The principal processes that occur in sediments are usually held to be of bacterial action and thermal transformation, which may include thermally induced catalytic alteration of the organic debris. On the other hand, radioactive materials are widely distributed throughout Earth. They were more abundant in the past, but are present in petroleum reservoirs. Their presence induced radioactive bombardment, which may have altered these sediments. This important subject has not been extensively studied. The aim of this work is to study the behavior of fatty acids-like behenic acid-and dicarboxylic acids-like fumaric acid-as model compounds, which are adsorbed in a clay mineral (Na-montmorillonite) and exposed to gamma radiation. The results show that the radiation-induced decomposition of the clay-acid system goes along a definitive path (oxidation), rather than following several modes of simultaneous decomposition, as happens in radiolysis without clay or by heating the system. The main radiolytic products for fatty acids are their corresponding hydrocarbons, with one C-atom less than the original acid.

  18. Combined air and water pollution control system

    Science.gov (United States)

    Wolverton, Billy C. (Inventor); Jarrell, Lamont (Inventor)

    1990-01-01

    A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system.

  19. Geotechnical studies of Jaitapur marine clay

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.T.; Nayak, B.U.

    characterisEd. by high water content and high Atterberg limits. Undrained shear strength varied from 1.8 to 6 KPa. These were moderately sensitive clays. Carbonate content which varied from 3 to 27%, was found to influence engineering properties of the soil...

  20. Sustainable Soil Water Management Systems

    OpenAIRE

    Basch, G.; Kassam, A.; Friedrich, T; Santos, F. L.; Gubiani, P.I.; Calegari, A.; J. M. Reichert; dos Santos, D.R.

    2012-01-01

    Soil quality and its management must be considered as key elements for an effective management of water resources, given that the hydrological cycle and land management are intimately linked (Bossio et al. 2007). Soil degradation has been described by Bossio et al. (2010) as the starting point of a negative cycle of soil-water relationships, creating a positive, self-accelerating feedback loop with important negative impacts on water cycling and water productivity. Therefore, sustainable soil...

  1. ASPECTS OF OPTIMIZATION OF WATER MANAGEMENT SYSTEMS

    Directory of Open Access Journals (Sweden)

    E. BEILICCI

    2013-03-01

    Full Text Available Water management system include all activities and works which providing the administration of public domain of water, with local / national interest, and qualitative, quantitative and sustainable management of water resources. Hydrotechnical arrangements, consisting of a set of hydraulic structures, produce both a favorable and unfavorable influences on environment. Their different constructive and exploitation solutions exercise a significantly impact on the environment. Therefore the advantages and disadvantages of each solution must be weighed and determined to materialize one or other of them seriously argued.The optimization of water management systems is needed to meet current and future requirements in the field of rational water management in the context of integrated water resources management. Optimization process of complex water management systems includes several components related to environmental protection, technical side and the business side. This paper summarizes the main aspects and possibilities of optimization of existing water management systems and those that are to be achieved.

  2. Water masers in the Kronian system

    NARCIS (Netherlands)

    Pogrebenko, Sergei V.; Gurvits, Leonid I.; Elitzur, Moshe; Cosmovici, Cristiano B.; Avruch, Ian M.; Pluchino, Salvatore; Montebugnoli, Stelio; Salerno, Emma; Maccaferri, Giuseppe; Mujunen, Ari; Ritakari, Jouko; Molera, Guifre; Wagner, Jan; Uunila, Minttu; Cimo, Giuseppe; Schilliro, Francesco; Bartolini, Marco; Fernández, J. A.; Lazzaro, D.; Prialnik, D.; Schulz, R.

    2010-01-01

    The presence of water has been considered for a long time as a key condition for life in planetary environments. The Cassini mission discovered water vapour in the Kronian system by detecting absorption of

  3. Clay modified crushed salt for shaft sealing elements. Material optimization and evaluation in field tests

    Energy Technology Data Exchange (ETDEWEB)

    Glaubach, Uwe; Hofmann, Martin; Gruner, Matthias; Kudla, Wolfram [TU Bergakademie Freiberg (Germany). Inst. of Mining and Special Civil Engineering

    2015-07-01

    Salt-based materials are intended to use for backfill and sealing systems in geotechnical barriers in underground HLW-repositories. Due to the creep of the saliniferous host rock, the salt backfill will be compacted during several hundreds or thousands years of operation to a minimum of porosity resp. permeability. To raise the sealing potential of a salt-based backfill, the porosity after construction should be minimized by optimal material performance and compaction performance. A procedure to optimize the grain size distribution of crushed salt and its water and clay content is described. The optimized salt fraction gets a better compaction behavior than straight mine-run salt. The addition of a filler-like material (e.g. Friedland Clay Powder) reduces the total porosity and permeability. Backfill columns made from crushed salt and clay probably include an instant sealing function.

  4. NEXAFS microscopy studies of the association of hydrocarbon thin films with fine clay particles

    Energy Technology Data Exchange (ETDEWEB)

    Covelli, Danielle [Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N 5C9 (Canada); Hernandez-Cruz, Daniel [Brockhouse Institute for Material Research, McMaster University, Hamilton, ON, L8S 4M1 (Canada); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Haines, Brian M. [Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N 5C9 (Canada); Munoz, Vincente; Omotoso, Oladipo; Mikula, Randy [CANMET Energy Technology Centre Natural Resources Canada, Devon, AB, T9G 1A8 (Canada); Urquhart, Stephen [Department of Chemistry, University of Saskatchewan, Saskatoon, SK, S7N 5C9 (Canada)], E-mail: stephen.urquhart@usask.ca

    2009-06-15

    The nature of organic species associated with clay minerals plays a significant role in several processes, from hydrocarbon recovery in oil sands to contaminated soil remediation and water treatment. In this work, we address the use of scanning transmission X-ray microscopy (STXM) in conjunction with near edge X-ray absorption fine structure (NEXAFS) spectroscopy to study the microstructure and chemistry of organic-clay associations in situ. A model system based on methylene blue and illite is used to explore the sensitivity of NEXAFS microscopy to these interactions, and to identify and resolve experimental challenges in these measurements. We find that sample contamination from X-ray induced photodeposition is a significant problem in STXM microscopy, but also that this problem can be substantially reduced with a liquid nitrogen cooled anticontaminator. With appropriate sample preparation and experimental procedures, we find that STXM microscopy is sensitive to thin carbon adsorbates on clay surfaces.

  5. Modeling in Ceramic Clay

    Science.gov (United States)

    Miller, Louis J.

    1976-01-01

    Modeling is an additive process of building up a sculpture with some plastic material like clay. It affords the student an opportunity to work in three dimensions, a creative relief from the general two-dimensional drawing and design activities that occupy a large segment of time in the art curriculum. (Author/RK)

  6. Magnificent Clay Murals

    Science.gov (United States)

    Kirker, Sara Schmickle

    2007-01-01

    Each August, third grade artists at Apple Glen Elementary in Bentonville, Arkansas, start the school year planning, creating, and exhibiting a clay relief mural. These mural projects have helped students to acquire not only art knowledge and techniques, but an even more important kind of knowledge: what it means to plan and successfully complete a…

  7. Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

    Science.gov (United States)

    Sarabadani, Hamid; Rayhani, Mohammad T

    2014-06-01

    Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner. PMID:24718363

  8. Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

    Science.gov (United States)

    Sarabadani, Hamid; Rayhani, Mohammad T

    2014-06-01

    Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner.

  9. 易盐渍区粘土夹层对土壤水盐运动的影响特征%Effect of clay interlayers on soil water-salt movement in easily-salinized regions

    Institute of Scientific and Technical Information of China (English)

    余世鹏; 杨劲松; 刘广明

    2011-01-01

    Large-scale soil column experiments for simulation water-salt movement in clay interlayers under normal growing conditions were carried out in an easily-salinized region for different textures of soils and groundwater conditions in the Huang-Huai-Hai alluvial plain of China. In this study, the 20-year measurement was analyzed to examine the effect of clay interlayers on soil water-salt movement in easily-salinized regions. Results show that the clay inter-layer has a significant positive effect on the water-holding capacity in the soil and acts as a filter obstructing the salinity infiltration. This is especially true for restraining the penetration of surface accumulated salts. The thicker the clay interlayer is, the greater the effect will be. The range of depth to groundwater is likely to be smaller in the area with surface accumulated salts and clay interlayers around 1.0 m than that with silt loam soils around 1.5 m. And in the latter case, the salinization of soils is easily induced when the groundwater level is lower than a threshold value of 2.5 m. The amount of accumulated salts is found to be higher in clay interlayers than that in silt loam soils. Thus, proper monitoring and measures are necessary to prevent the secondary salinization of soils in the practice of water resources management.%针对黄淮海冲积平原土壤剖面中粘土夹层普遍存在的现象,在典型易盐渍区开展模拟易盐农田常规种植条件下水盐运移的大型土柱实验,基于长达20年的长系列监测数据分析,系统研究易盐渍区不同土体构型和地下水位等代表性条件下的土壤水盐运移规律和粘土夹层的影响特征.研究结果表明:粘土层有良好的保水和隔盐能力,尤其对表土积盐的抑制效果显著,且抑盐效果随粘土层厚度增加而提升;含粘土夹层土体表土积盐的地下水埋深范围更小,表土积盐高峰出现在l m左右地下水埋深,全剖面粉砂壤土土体

  10. Biofilm formation in a hot water system

    DEFF Research Database (Denmark)

    Bagh, L.K.; Albrechtsen, Hans-Jørgen; Arvin, Erik;

    2002-01-01

    The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached......, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore...

  11. Synthesis and properties of P(NIPA-co-NVP)-clay hydrogel by radiation polymerization

    International Nuclear Information System (INIS)

    Polymeric hydrogels are unique materials that can absorb and retain large amounts of water. The cross-linking of polymer chain makes them insoluble, soft and elastic. They are stimuli-responsive, displaying phase transitions in response to small changes in temperature, pH, electric field and light. The temperature-sensitive hydrogels have potential applications in gel-based separation processes and in biomedicine, e.g., preparation of drug delivery systems and separation of cells. Thermo-sensitive character of poly (N-isopropylacrylamide) (NIPAm) hydrogels shrinking or swelling below or above lower critical solution temperature (LCST) has widely been investigated in recent years. However, some of their potential applications are hindered by their low mechanical strength, low swelling ratio, bad biocompatibility and low purity, owing to the use of catalysts or additives in chemosynthesis. Liang synthesized clay/PNIPAm composite hydrogel to improve its mechanical strength. In this work, hydrogels of P (NIPA-co-NVP)-Clay were synthesized by 60Co γ-ray irradiation. Different thermo-sensitive hydrogels were made under different experimental conditions such as dose, dose rate, monomer concentration, monomer ratio and content of clay. X-ray diffraction shows that the layer distance of Na-clay is changed from 1.6nm to 2.7nm because Na-clay pieces can be intercalated or exfoliated by HTMAB, and P(NIPA-co-NVP) -clay pieces is 3.4nm. The swelling property tests show that the LCST of PNIPA is 32 degree C, the LCST of P(NIPA-co-NVP) is higher than PNIPA. With the increase of NVP content, LCST is higher. As the ratio of NIPA/NVP is 95/5, hydrogel shows the best swelling property and LCST is 37 degree C. LCST of P(NIPA-co-NVP)-clay Hydrogel is not changed, but the strength and swelling properties are better. (authors)

  12. Small Drinking Water Systems Research and Development

    Science.gov (United States)

    In the United States, there are 152,002 public water systems (PWS) in operation. Of these, 97% are considered small systems under the Safe Drinking Water Act (SDWA)—meaning they serve 10,000 or fewer people. While many of these small systems consistently provide safe, relia...

  13. Effect of air injection under subsurface drip irrigation on yield and water use efficiency of corn in a sandy clay loam soil

    OpenAIRE

    Mohamed Abuarab; Ehab Mostafa; Mohamed Ibrahim

    2013-01-01

    Subsurface drip irrigation (SDI) can substantially reduce the amount of irrigation water needed for corn production. However, corn yields need to be improved to offset the initial cost of drip installation. Air-injection is at least potentially applicable to the (SDI) system. However, the vertical stream of emitted air moving above the emitter outlet directly toward the surface creates a chimney effect, which should be avoided, and to ensure that there are adequate oxygen for root respiration...

  14. Clay Animals and Their Habitats

    Science.gov (United States)

    Adamson, Kay

    2010-01-01

    Creating clay animals and their habitats with second-grade students has long been one of the author's favorite classroom activities. Students love working with clay and they also enjoy drawing animal homes. In this article, the author describes how the students created a diorama instead of drawing their clay animal's habitat. This gave students…

  15. Bauxite washing for the removal of clay

    Science.gov (United States)

    Ahmad, Ishaq; Hartge, Ernst-Ulrich; Werther, Joachim; Wischnewski, Reiner

    2014-11-01

    Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay (mainly rich in silica). Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory: drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

  16. Bauxite washing for the removal of clay

    Institute of Scientific and Technical Information of China (English)

    Ishaq Ahmad; Ernst-Ulrich Hartge; Joachim Werther; and Reiner Wischnewski

    2014-01-01

    Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay (mainly rich in silica). Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory: drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

  17. Water Desalination Systems Powered by Solar Energy

    Science.gov (United States)

    Barseghyan, A.

    2015-12-01

    The supply of potable water from polluted rivers, lakes, unsafe wells, etc. is a problem of high priority. One of the most effective methods to obtain low cost drinking water is desalination. Advanced water treatment system powered by Solar Energy and based on electrodialysis for water desalination and purification, is suggested. Technological and economic evaluations and the benefits of the suggested system are discussed. The Advanced Water Treatment System proposed clears water not only from different salts, but also from some infections, thus decreasing the count of diseases which are caused by the usage of non-clear water. Using Solar Energy makes the system stand alone which is convenient to use in places where power supply is problem.

  18. Impact of the changes in the chemical composition of pore water on chemical and physical stability of natural clays. A review of natural cases and related laboratory experiments and the ideas on natural analogues for bentonite erosion/non-erosion

    International Nuclear Information System (INIS)

    A scientific literature survey was compiled with the specific objective to find information for smectite mobilization and/or retention in natural clay formations caused by contact with water with low ionic concentrations such as can be expected during and after an ice age. Evidence was sought if smectite particles are lost from the clay to the water and if accessory minerals that remain could form a growing filter slowing down or stopping further loss of smectite. Bentonites are present in geological layers for hundreds of millions of years. There is limited exchange with surrounding layers, eg K transported into the bentonite layer from surrounding shale layers leading to the increased illite % in smectite-illite of the bentonite. Another process is silicification of surrounding layers leading to lowered permeability of surrounding rocks. Geological literature data on historical bentonites do not consider colloid formation in low ionic strength water as relevant mechanism for smectite mobilization. However there are no studied cases where this could be a relevant mechanism (as proposed by colloid release scenario). Soil researchers have studied the mechanism of colloid release in laboratory experiments and have found that there has to be an abrupt change in infiltrating water quality leading to 'osmotic explosion'. Clogging the pores in the lower part of the soil column has followed, leading to dramatic decrease of hydraulic conductivity in vertical profile and increased surface runoff. So, although limited, there are literature evidences of clay colloids release from bentonites/smectites caused by low-ionic circumneutral water. The geological settings to look for natural analogue studies include (1) Bentonite/smectite similar to what is used in repository. (2) Water similar to the composition of glacial meltwater. (3) Scenario similar to what is proposed in the bentonite erosion project. The problem related to the study of historical bentonite profiles is the

  19. CMC use as colloid protector in water and clay basis drilling fluids: part II; Uso do CMC como coloide protetor em fluidos de perfuracao a base de agua e argilas: parte II

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Luciana Viana [Universidade Federal, Campina Grande, PB (Brazil). Engenharia de Processos]. E-mail: lucianaa@labdes.ufpb.br; Viana, Josiane Dantas; Farias, Kassie Vieira; Lira, Helio de Lucena; Ferreira, Heber Carlos [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Engenharia de Materiais]. E-mail: josianedantas@bol.com.br; kassievieira@bol.com.br; helio@dema.ufpb.br; heber@dema.ufpb.br; Franca, Kepler Borges [Universidade Federal, Campina Grande, PB (Brazil). Dept. de Eng. Quimica]. E-mail: kepler@labdes.ufpb.br

    2003-07-01

    The aim of this work is to study the protect effect of the low viscosity carboxymethyl cellulose (CMC) on water based oil well drilling fluids and bentonite clays treated with sodium, additivated with degrading agents. The drilling fluids were prepared with a concentration of 4.86% w/w, according to PETROBRAS norms. It was studied three samples of natural bentonite clays treated with Na{sub 2}CO{sub 3}, from Boa Vista, PB. The drilling fluids were treated with three different concentration of CMC and submitted to a cure for a period of 24 hours. After it were added degrading agents (CaCl{sub 2} + MgCl{sub 2}). Also, it was done the treatment in a reverse order, i.e., first the drilling fluids were treated with degrading agents and after with CMC. It was measured apparent viscosity (AV), plastic viscosity (PV) by using a Fann Viscosimeter and water loss (WL), by using a Fann filter press. The results showed that CMC protect the drilling fluids from the flocculating effect of calcium and magnesium and stop the damage caused by degrading agents. Also, the order of the treatment (degrading agent - CMC) does not present significant influence in the rheological properties of the studied drilling fluids. (author)

  20. ASPECTS OF OPTIMIZATION OF WATER MANAGEMENT SYSTEMS

    OpenAIRE

    E. BEILICCI; R. BEILICCI

    2013-01-01

    Water management system include all activities and works which providing the administration of public domain of water, with local / national interest, and qualitative, quantitative and sustainable management of water resources. Hydrotechnical arrangements, consisting of a set of hydraulic structures, produce both a favorable and unfavorable influences on environment. Their different constructive and exploitation solutions exercise a significantly impact on the environment. Therefore the advan...

  1. Functional systems of a pressurized water reactor

    International Nuclear Information System (INIS)

    The main topics, discussed in the present paper, are: - Principle design of the reactor coolant system - reactor pressure vessel with internals - containment design - residual heat removal and emergency cooling systems - nuclear component cooling systems - emergency feed water systems - plant electric power supply system. (orig./RW)

  2. Characterization of aquifer heterogeneity in a complex fluvial hydrogeologic system to evaluate migration in ground water

    International Nuclear Information System (INIS)

    The hydrogeology and extent of ground water contamination were characterized at a site in northern California. Wood preserving compounds, primarily pentachlorophenol (PCP) and creosote, have been detected in the soil and ground water. A plume of dissolved PCP up to 1.5 miles long has been identified south of the plant. The aquifer consists of a complex multizonal system of permeable gravels and sands composed of units from four geologic formations deposited by the ancestral Feather River. Fluvial channel gravels form the principal aquifer zones and contain overbank clay and silt deposits which locally form clay lenses or more continuous aquitards. The geometric mean horizontal hydraulic conductivities for channel gravels range between 120 to 530 feet/day. Mean vertical aquitard hydraulic conductivity is 0.07 feet/day. Ground water flow is generally southward with a velocity ranging from 470 to 1000 feet/year. The spatial distribution of dissolved PCP in the aquifer documents the interactions between major permeable zones. Hydrostratigraphic evidence pointing to the separation of aquifer zones is supported by the major ion chemistry of ground water. The sodium and calcium-magnesium bicarbonate-rich water present in the upper aquifer zones is significantly different in chemical composition from the predominantly sodium chloride-rich water present in the deeper permeable zone. This indicates that hydrodynamic separation exists between the upper and lower zones of the aquifer, limiting the vertical movement of the PCP plume. A numerical ground water model, based on this conceptual hydrogeologic model, was developed to evaluate groundwater transport pathways and for use in the design of a ground water extraction and treatment system. (9 refs., 7 figs., tab.)

  3. Water masers in the Saturnian system

    Science.gov (United States)

    Pogrebenko, S. V.; Gurvits, L. I.; Elitzur, M.; Cosmovici, C. B.; Avruch, I. M.; Montebugnoli, S.; Salerno, E.; Pluchino, S.; Maccaferri, G.; Mujunen, A.; Ritakari, J.; Wagner, J.; Molera, G.; Uunila, M.

    2009-02-01

    Context: The presence of water has long been seen as a key condition for life in planetary environments. The Cassini spacecraft discovered water vapour in the Saturnian system by detecting absorption of UV emission from a background star. Investigating other possible manifestations of water is essential, one of which, provided physical conditions are suitable, is maser emission. Aims: We report detection of water maser emission at 22 GHz associated with several Kronian satellites using Earth-based radio telescopes. Methods: We searched for water maser emission in the Saturnian system in an observing campaign using the Metsähovi and Medicina radio telescopes. Spectral data were Doppler-corrected over orbital phase for the Saturnian satellites, yielding detections of water maser emission associated with the moons Hyperion, Titan, Enceladus, and Atlas. Results: The detection of Saturnian water molecules by remote astronomical observation can be combined with in situ spacecraft measurements to harmonise the physical model of the Saturnian system.

  4. Service Water System Inspection Locator (SWSIL)

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, M.L.; Tang, S.S.; Carney, C.E.; Licina, G.J. (Structural Integrity Associates, Inc., San Jose, CA (United States))

    1993-04-01

    Inspection and maintenance of a service water system is a key to reliable system operation. As emphasized by NRC Generic Letter 89-13, service water system reliability in nuclear plants must by assured since the SWS may support safety related equipment The diversity of design, water chemistry, and operating regimens, coupled with the tremendous size of these systems (literally miles of piping and hundreds of heat exchangers) makes the selection of locations to be inspected a difficult chore. In cooperation with the Electric Power Research Institute (EPRI) and the New York Power Authority (NYPA), a Service Water System Inspection Locator (SWSIL) has been developed to explore the feasibility of using an expert system to evaluate the corrosion susceptibility of the thousands of locations and components associated with nuclear service water systems (SWS). Such an expert system provides utilities with a method for planning and prioritizing inspections. SWSIL, Version 1.0, has been applied to the emergency diesel generator service water cooling loop of the emergency service water (ESW) system of the James A. FitzPatrick plant. The feasibility demonstration described in this report provided a framework for applying SWSIL to a system of any size. The demonstration also showed that refinement of the plant data input interface and flow modeling are required. Applicability of SWSIL in its current configuration to large systems is limited and awaits these improvements.

  5. 某泥塑殿消防设施方案选择分析%Analysis on the design plan of some clay hall's fire extinguishing system

    Institute of Scientific and Technical Information of China (English)

    王巍

    2013-01-01

    Against the decision of fire extinguishing system for some clay hall of national key cultural relics protection units,choose 4 index including fire extinguishing effect,secondary disaster,difficulty of installation and maintain,quantity of structural renovation project,and use risk assessment and fuzzy mathematics to analyze 4 common fire extinguishing system.Results showed that the most suitable one is ABC fine dry powder fire extinguishing system,and then IG541 gas fire extinguishing system,automatic sprinkler system,and ordinary ABC dry powder fire extinguishing system.After considering the protection of cultural relics,decide to choose cabinet fine dry powder fire extinguishing system,and fire control methods were put forward.%针对某全国重点文物保护单位泥塑殿拟选用的灭火系统,选择灭火效果、灭火系统产生的次生灾害、安装维护难度、结构改造工程量4个指标,应用风险评价方法和模糊数学理论对4种常见灭火系统进行分析得知,最适用于大殿的灭火系统是ABC超细干粉灭火系统,其次是IG541气体灭火系统、自动喷水预作用系统、普通ABC干粉灭火系统.进一步考虑文物保护等因素,指出大殿宜选择柜式ABC超细干粉灭火装置,并提出了现阶段大殿火灾防控措施.

  6. CO2 production from the Boom clay under thermal load

    International Nuclear Information System (INIS)

    Boom Clay kerogen is about 55 mg/g of kerogen (∼72 mg/g TOC) according to Deniau et al. (2005) and 49 mg/g of organic carbon based on the data of Lorant et al. (2008). However, these results were derived from anhydrous closed system experiments using purified kerogen without mineral matrix. Therefore they reflect only parts of the reactive properties of organic matter in repository conditions. More recently, pyrolyses tests were performed at 150-200 C on both isolated kerogen and bulk Boom Clay samples in the presence of liquid phase in order to account for potential role of water and minerals on the formation of CO2. The absolute amount of CO2 appeared higher in the bulk Boom Clay compared to CO2 released from the kerogen for the same set of experimental conditions. Furthermore, the shapes of the CO2 production curves are clearly different for the two studied cases. In the bulk samples, CO2 production curves follow reversal trends, while typical steady-state curves are observed in case of isolated kerogen. Whether or not CO2-carbonate equilibrium reactions interfered with CO2 production from organic matter in the bulk rock Boom Clay samples is a hypothesis being tested. Long-term batch experiments at 80 C are currently running at SCK.CEN to shed more light on the CO2 production from the bulk rock suspensions. The gas analysis confirmed that CO2 is by far the major gaseous component formed upon heating. The concentrations of methane are systematically below detection limit indicating that no significant C-C cleavage took place and thus internal structure of kerogen remained intact. The gas quantities fall within the range of 44-60 mgCO2/g TOC as measured on three independent cells. Taking into account the used high L/S ratio, the produced CO2 quantities are considered as the maximum capacity of the Boom Clay to release CO2 gas at 80 C. An overview of CO2 amounts produced by heating of BC kerogen and bulk rock samples from various experiments is given in Figure 1. The

  7. Kansas Water Quality Action Targeting System (KATS)

    Data.gov (United States)

    Kansas Data Access and Support Center — This system is a revision of the original KATS system developed in 1990 as a tool to aid resource managers target Kansas valuable and vulnerable water resources for...

  8. Prototype solar domestic hot water systems

    Science.gov (United States)

    1978-01-01

    Construction of a double wall heat exchanger using soft copper tube coiled around a hot water storage tank was completed and preliminary tests were conducted. Solar transport water to tank potable water heat exchange tests were performed with a specially constructed test stand. Work was done to improve the component hardware and system design for the solar water heater. The installation of both a direct feed system and a double wall heat exchanger system provided experience and site data to enable informative decisions to be made as the solar market expands into areas where freeze protection is required.

  9. Defect and Innovation of Water Rights System

    Institute of Scientific and Technical Information of China (English)

    Zhou Bin

    2008-01-01

    The rare deposition of water resources conflicts with its limitless demand. This determined the existence of the water rights transaction system. The implementation of the water rights transaction system requires clarifying the definition of water re-source fight above all distinctly. At present, it is a kind of common right system arrangement which needs the Chinese government to dispose of water resources. Though a series of management sys-tems guaranteed the government's supply of water resource, it hindered the development of the water market seriously and caused the utilization of water resources to stay in the inefficient or low efficient state for a long time. Thus, we should change the government's leading role in the resource distribution and really rely on the market to carry on the water rights trade and transac-tion. In this way, the water rights could become a kind of private property right relatively, and circulate freely in the market. As a result of this, we should overcome the defects of common right, make its external performance internalized maximally and achieve the optimized water resource disposition and use it more effec-tively.

  10. Basics of Solar Heating & Hot Water Systems.

    Science.gov (United States)

    American Inst. of Architects, Washington, DC.

    In presenting the basics of solar heating and hot water systems, this publication is organized from the general to the specific. It begins by presenting functional and operational descriptions of solar heating and domestic hot water systems, outlining the basic concepts and terminology. This is followed by a description of solar energy utilization…

  11. Solar-powered hot-water system

    Science.gov (United States)

    Collins, E. R.

    1979-01-01

    Hot-water system requires no external power except solar energy. System is completely self-controlling. It includes solar-powered pump, solar-thermally and hydrothermally operated valves, and storage tank filled with open-celled foam, to maintain thermal stratification in stored water.

  12. RESEARCH OF SWELLING OF SUZAKH CLAYS

    Directory of Open Access Journals (Sweden)

    Kubetskiy Valeriy Leonidovich

    2012-07-01

    Full Text Available In the course of construction of Sangtudinsky hydropower plant-1 on the River Vakhsh, it was deemed necessary to identify clay swelling properties in the event of alterations of the humidity mode of fructured half-rock soils, or the Suzakh clay, that accommodated tunnel-shaped water outlets within a section that was 75 meters long. The depth of tunnels was about 100 m. Any interaction with swelling soils could lead to destruction of the tunnel lining. Suzakh clays demonstrated the following physical and mechanical properties: density of particles of soil ρ= 2,69 g/cm; soil density ρ = 2.40-2.47 g/cm; porosity of 8.2-10.8 %; ultimate resistance to uniaxial compression = 13.1-31.0 MPa. Water saturated clay samples disintegrated into cloddy fragments; the rate of a longitudinal ultrasonic wave in the area of unaltered soils was equal to = 2500 m/c; repulse coefficient k was equal to 15 MPa/m; solidity coefficient (according to Protodyakonov was equal to 1,5; modulus of deformation in the massif was equal to 0.23 х10 MPa. The author proposed a methodology and designed a pilot set of equipment units designated for the identification of the swelling properties of fractured half-rock soils. Results of the pilot unit operation are presented in the article. Swelling properties are based on the monolith testing results. The programme contemplated a set of experiments held in various limit states on the surface of monoliths. Dependence between the swelling pressure and the swelling deformation in the course of water saturation was identified. The experiment demonstrates that alterations of the humidity mode of free surface Suzakh clays cause the relative deformation of swelling up to 1.1 %, and if the lining is rigid, the swelling pressure can exceed 4 MPa.

  13. MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

    Energy Technology Data Exchange (ETDEWEB)

    Robert L. Lee; Junghan Dong

    2004-06-03

    This final report of ''Modified Reverse Osmosis System for Treatment of Produced Water,'' DOE project No. DE-FC26-00BC15326 describes work performed in the third year of the project. Several good results were obtained, which are documented in this report. The compacted bentonite membranes were replaced by supported bentonite membranes, which exhibited the same salt rejection capability. Unfortunately, it also inherited the clay expansion problem due to water invasion into the interlayer spaces of the compacted bentonite membranes. We noted that the supported bentonite membrane developed in the project was the first of its kind reported in the literature. An {alpha}-alumina-supported MFI-type zeolite membrane synthesized by in-situ crystallization was fabricated and tested. Unlike the bentonite clay membranes, the zeolite membranes maintained stability and high salt rejection rate even for a highly saline solution. Actual produced brines from gas and oil fields were then tested. For gas fields producing brine, the 18,300 ppm TDS (total dissolved solids) in the produced brine was reduced to 3060 ppm, an 83.3% rejection rate of 15,240 ppm salt rejection. For oilfield brine, while the TDS was reduced from 181,600 ppm to 148,900 ppm, an 18% rejection rate of 32,700 ppm reduction, the zeolite membrane was stable. Preliminary results show the dissolved organics, mainly hydrocarbons, did not affect the salt rejection. However, the rejection of organics was inconclusive at this point. Finally, the by-product of this project, the {alpha}-alumina-supported Pt-Co/Na Y catalytic zeolite membrane was developed and demonstrated for overcoming the two-step limitation of nonoxidation methane (CH{sub 4}) conversion to higher hydrocarbons (C{sub 2+}) and hydrogen (H{sub 2}). Detailed experiments to obtain quantitative results of H{sub 2} generation for various conditions are now being conducted. Technology transfer efforts included five manuscripts submitted to

  14. Wash water waste pretreatment system

    Science.gov (United States)

    1977-01-01

    Investigations were completed on wash waters based on each candidate personal cleansing agent. Evaluations of coagulants, antifoam agents, and the effect of promising antifoams on the chemical precipitation were included. Based on these evaluations two candidate soaps as well as their companion antifoam agents were selected for further work. Operating parameters included the effect of soap concentration, ferric chloride concentration, duration of mixing, and pore size of depth filters on the degree of soap removal. The effect of pressure on water flow through filter cartridges and on the rate of decline of water flow was also investigated. The culmination of the program was the recommendation of a pretreatment concept based on chemical precipitation followed by pressure filtration.

  15. In situ analysis of microbial reduction of a nitrate plume in Opalinus clay

    International Nuclear Information System (INIS)

    nitrate and nitrite concentrations and pH, an on-line UV spectrophotometer and pH electrode are installed in the water circuit of one of the intervals. In a first series of tests, the biogeochemical evolution of the artificial Opalinus Clay pore water in the intervals was investigated after injection of low concentrations of nitrate or nitrate and acetate, simulating the BDP. The results of these tests indicate that microbial reduction of nitrate and nitrite can occur in the Opalinus Clay artificial water in the borehole, using acetate and/or clay components as electron donors. In these tests, nitrate was reduced to nitrite, ammonium and/or nitrogenous gases. Comparing the evolution in nitrate and nitrite concentrations in the absence or presence of acetate, clearly indicates faster reaction rates of microbial nitrate reduction when the system is fueled with acetate. When easily degradable organic compounds like acetate were added to the nitrate containing artificial pore water, these compounds were preferentially used as electron donors for nitrate reduction by heterotrophic microorganisms. Afterwards, alternative electron donors have been used originating either from the clay rock, e.g. pyrite, siderite, clay minerals, and/or dissolved natural organic matter, or from the stainless steel equipment, i.e. Fe0 and/or Fe2+. Furthermore, high concentrations of nitrate reducing prokaryotes were detected after injection of the intervals with nitrate, indicating that the nitrate and nitrite reduction, observed during all tests, was microbially mediated. Based on the results of the microbiological analyses, these nitrate reducers have most likely been introduced during the first injection or installation of the downhole equipment. The nature of the nitrate reduction reaction prevailing in the system appears to be depending on the microbial populations active in the borehole and on the electron donors and carbon sources present in the interval. Furthermore, the history of the

  16. Mud peeling and horizontal crack formation in drying clays

    KAUST Repository

    Style, Robert W.

    2011-03-01

    Mud peeling is a common phenomenon whereby horizontal cracks propagate parallel to the surface of a drying clay. Differential stresses then cause the layer of clay above the crack to curl up to form a mud peel. By treating the clay as a poroelastic solid, we analyze the peeling phenomenon and show that it is caused by the gradient in tensile stress at the surface of the clay, analogously to the spalling of thermoelastic materials. For a constant water evaporation rate at the clay surface we derive equations for the depth of peeling and the time of peeling as functions of the evaporation rate. Our model predicts a simple relationship between the radius of curvature of a mud peel and the depth of peeling. The model predictions are in agreement with the available experimental data. Copyright 2011 by the American Geophysical Union.

  17. Geochemical simulation of the evolution of granitic rocks and clay minerals submitted to a temperature increase in the vicinity of a repository for spent nuclear fuel

    International Nuclear Information System (INIS)

    The alteration of a granitic rock around a repository for spent nuclear fuel has been simulated considering the effect of an increase of temperature due to this kind of induced geothermal system. The results of the simulation have been interpreted in terms of mass transfer and volumic consequences. The alteration proceeds by dissolution of minerals (with an increase of the volumes of fissures and cracks) and precipitation of secondary miminerals as calcite and clay minerals particularly (with a decrease of the porosity). The increase of the temperature from 10 degrees C to about 100 degrees C will favour the alteration of the granitic rock around the repository by the solution filling the porosity. The rock is characterized by a very low fissure porosity and a consequent very low water velocity. This too, favours intense water rock interactions and production of secondary clays and the total possible mass transfer will decrease the porosity. A combination of these thermodynamic mass balance calculations with a kinetic approach of mineral dissolutions gives a first attempt to calibrate the modelling in the time scale: the decrease of porosity can be roughly estimated between 2 and 20% for 100,000 years. The particular problem of Na-bentonites behaviour in the proximate vicinity of the repository has been studied too. One must distinguish between two types of clay-water interactions: -within the rock around the repository, Na-bentonites should evolute with illitization in slighltly open system with low clay/water ratios, -within the repository itself, the clay reacts in a closed system for a long time with high clay/water ratios and a self-buffering effect should maintain the bentonite type. This chemical buffering effect is a positive point for the use of this clay as chemical barrier. (Author)

  18. Recyclable hydrotalcite clay catalysed Baylis-Hillman reaction

    Indian Academy of Sciences (India)

    Vivek Srivastava

    2013-09-01

    The Baylis-Hillman reaction using ionic liquid/hydrotalcite clay catalytic system has been observed to be more reactive in terms of yield and reaction rate than DABCO/acetonitrile system. During the process, the reactants enjoy ionic liquid/hydrotalcite clay catalytic system and gives corresponding Baylis-Hillman reaction products in good yield. The application of our catalytic system has been diversifying for the synthesis of lactone ceramide analogue from (S)-Garner aldehyde-methyl acrylate using Baylis-Hillman reaction. Recycling of ionic liquid/hydrotalcite clay catalytic system has also been demonstrated in this report.

  19. Preoperational test report, raw water system

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-10-29

    This represents the preoperational test report for the Raw Water System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system supplies makeup water to the W-030 recirculation evaporative cooling towers for tanks AY1O1, AY102, AZ1O1, AZ102. The Raw Water pipe riser and associated strainer and valving is located in the W-030 diesel generator building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  20. Water turbine system and method of operation

    Science.gov (United States)

    Costin, Daniel P.

    2010-06-15

    A system for providing electrical power from a current turbine is provided. The system includes a floatation device and a mooring. A water turbine structure is provided having an upper and lower portion wherein the lower portion includes a water fillable chamber. A plurality of cables are used to couple the system where a first cable couples the water turbine to the mooring and a second cable couples the floatation device to the first cable. The system is arranged to allow the turbine structure to be deployed and retrieved for service, repair, maintenance and redeployment.

  1. Comparative assessment of water infiltration of soils under different tillage systems in eastern Botswana

    Science.gov (United States)

    Moroke, T. S.; Dikinya, O.; Patrick, C.

    Water infiltration is an important component of water balance for improving crop production potential in dryland soil tillage systems in Botswana, particularly in the eastern region. Hardsetting soils common in arable lands of Botswana, often require some kind of tillage such as mouldboard ploughing, chiselling and ripping to improve waterharvesting and crop growth conditions. The objective of this study was to compare ponded cumulative infiltration, steady state infiltration rate and sorptivity of soils cultivated using deep ripping, single and double mouldboard ploughing. This study was conducted on Chromic Luvisols (sandy loam), Haplic Luvisols (sandy clay loam), Ferric Luvisols (clay loam), and Ferric Arenosols (sand). Infiltration was measured using double ring infiltrometer method for 4 h. Although infiltration was smaller on traffic line of deep ripping system at all sites, it was only significantly ( P 0.05) different under deep ripped. Cumulative and steady state infiltration rate was greater under sandy than loamy soils, smaller under double ploughing compared with single ploughed and deep ripped soils. Sorptivity was not significantly ( P > 0.05) different among tillage systems but was greater under sandy than sandy loam soils. Information on tillage and infiltration can improve implementation of waterharvesting technologies and crop production in Botswana.

  2. Comparing specialised and mixed farming systems in the clay areas of the Netherlands under future policy scenarios : an optimisation approach

    NARCIS (Netherlands)

    Bos, J.F.F.P.

    2002-01-01

    Keywords: interdisciplinary analysis, mixed farming, linear programming, agricultural policy, environmental policyIncreasing attention for the sustainability concept also caused renewed interest in mixed farming systems in the Netherlands, which supposedly have some advantages over specialised farmi

  3. Clays, clay minerals and cordierite ceramics - a review

    OpenAIRE

    Marta Valaskova

    2015-01-01

    The conventional methods for the synthesis of cordierite ceramics include the solid-state sintering of individual oxides of magnesium, aluminium and silicon of the corresponding chemical composition of cordierite, or sintering of the natural raw materials. Clays are used in the ceramics industries largely because of their contribution to the molding and drying properties. The most effective use of clays meets with the problems of the improvement of the working properties of clays and...

  4. Characterization of groundwater dynamics in landslides in varved clays

    Directory of Open Access Journals (Sweden)

    J. E. van der Spek

    2013-01-01

    Full Text Available Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trièves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and cut through by fissures. The hydraulic conductivity of the clay layers is negligible compared to the silt layers. It is conceptualized that fissures form a hydraulic connection between the colluvium and the varved clays. Groundwater recharge flows through the colluvium into the fissures where water is exchanged horizontally between the fissure and the silt layers of the varved clays. Groundwater flow in the colluvium is simulated with the Boussinesq equation while flow in the silt layers of the varved clays is simulated with the Richards' equation. Longitudinal outflow from the fissure is simulated with a linear-reservoir model. Scattered data of relatively short monitoring periods is available for several landslides in the region. A good similarity between observed and simulated heads is obtained, especially when considering the lack of important physical parameters such as the fissure width and the distance between the monitoring point and the fissure. A simulation for the period 1959–2004 showed some correlation between peaks in the simulated heads and the recorded occurrence of landslides while the bottom of the varved clays remained saturated during the entire simulation period.

  5. Screening reactor steam/water piping systems for water hammer

    International Nuclear Information System (INIS)

    A steam/water system possessing a certain combination of thermal, hydraulic and operational states, can, in certain geometries, lead to a steam bubble collapse induced water hammer. These states, operations, and geometries are identified. A procedure that can be used for identifying whether an unbuilt reactor system is prone to water hammer is proposed. For the most common water hammer, steam bubble collapse induced water hammer, six conditions must be met in order for one to occur. These are: (1) the pipe must be almost horizontal; (2) the subcooling must be greater than 20 C; (3) the L/D must be greater than 24; (4) the velocity must be low enough so that the pipe does not run full, i.e., the Froude number must be less than one; (5) there should be void nearby; (6) the pressure must be high enough so that significant damage occurs, that is the pressure should be above 10 atmospheres. Recommendations on how to avoid this kind of water hammer in both the design and the operation of the reactor system are made

  6. Reactor water level control system

    International Nuclear Information System (INIS)

    A BWR type reactor comprises a control valve disposed in a reactor water draining pipelines and undergoing an instruction to control the opening degree, an operation board having a setting device for generating the instruction and a control board for giving the instruction generated by the setting device to the control valve. The instruction is supplied from the setting device to the control valve by way of a control circuit to adjust the opening degree of the control valve thereby controlling the water level in the reactor. In addition, a controller generating an instruction independent of the setting device and a signal transmission channel for signal-transmitting the instruction independent of the control circuit are disposed, to connect the controller electrically to the signal transmission. The signal transmission channel and the control circuit are electrically connected to the control valve switchably with each other. Since instruction can be given to the control valve even at a periodical inspection or modification when the setting device and the control circuit can not be used, the reactor water level can be controlled automatically. Then, operator's working efficiency upon inspection can be improved remarkably. (N.H.)

  7. Integrated waste and water management system

    Science.gov (United States)

    Murray, R. W.; Sauer, R. L.

    1986-01-01

    The performance requirements of the NASA Space Station have prompted a reexamination of a previously developed integrated waste and water management system that used distillation and catalytic oxydation to purify waste water, and microbial digestion and incineration for waste solids disposal. This system successfully operated continuously for 206 days, for a 4-man equivalent load of urine, feces, wash water, condensate, and trash. Attention is given to synergisms that could be established with other life support systems, in the cases of thermal integration, design commonality, and novel technologies.

  8. Toxicological evaluation of clay minerals and derived nanocomposites: a review.

    Science.gov (United States)

    Maisanaba, Sara; Pichardo, Silvia; Puerto, María; Gutiérrez-Praena, Daniel; Cameán, Ana M; Jos, Angeles

    2015-04-01

    Clays and clay minerals are widely used in many facets of our society. This review addresses the main clays of each phyllosilicate groups, namely, kaolinite, montmorillonite (Mt) and sepiolite, placing special emphasis on Mt and kaolinite, which are the clays that are more frequently used in food packaging, one of the applications that are currently exhibiting higher development. The improvements in the composite materials obtained from clays and polymeric matrices are remarkable and well known, but the potential toxicological effects of unmodified or modified clay minerals and derived nanocomposites are currently being investigated with increased interest. In this sense, this work focused on a review of the published reports related to the analysis of the toxicological profile of commercial and novel modified clays and derived nanocomposites. An exhaustive review of the main in vitro and in vivo toxicological studies, antimicrobial activity assessments, and the human and environmental impacts of clays and derived nanocomposites was performed. From the analysis of the scientific literature different conclusions can be derived. Thus, in vitro studies suggest that clays in general induce cytotoxicity (with dependence on the clay, concentration, experimental system, etc.) with different underlying mechanisms such as necrosis/apoptosis, oxidative stress or genotoxicity. However, most of in vivo experiments performed in rodents showed no clear evidences of systemic toxicity even at doses of 5000mg/kg. Regarding to humans, pulmonary exposure is the most frequent, and although clays are usually mixed with other minerals, they have been reported to induce pneumoconiosis per se. Oral exposure is also common both intentionally and unintentionally. Although they do not show a high toxicity through this pathway, toxic effects could be induced due to the increased or reduced exposure to mineral elements. Finally, there are few studies about the effects of clay minerals on

  9. On the thermal behaviour of Boom clay

    Energy Technology Data Exchange (ETDEWEB)

    Delage, P.; Cui Yu Jun [Ecole Nationale des Ponts et Chaussees, Paris (France); Sultan, N. [IFREMER, Brest (France)

    2004-07-01

    When temperature is increased, the various phenomena that occur in a saturated natural potential host clay for nuclear waste disposal (Boom clay from SCK-CEN in Mol, Belgium) were experimentally investigated in a temperature controlled high stress triaxial cell. Firstly, the pore pressure build-up due to the difference in thermal dilation of both water and minerals was investigated through thermal consolidation tests. Interesting information was obtained about the dissipation of thermally induced pore pressure in Boom clay, based on the standard Terzaghi consolidation theory. Secondly, the volume change behaviour in drained conditions (i.e. under a very slow temperature increase) confirmed that the clay overconsolidation ratio (OCR) controlled the nature of the volume changes. Whereas overconsolidated soils use to dilate as any material when temperature is elevated, normally consolidated soils present a decrease in volume, which is less common. The principles of a coupled thermo-elasto-plastic model that was specifically developed to model this particular behaviour are finally presented. Obviously, it appears necessary to account in detail for these thermal phenomena in order to properly understand the response of the geological barrier in the near field once nuclear waste has been stored. (orig.)

  10. On the thermal behaviour of Boom clay

    International Nuclear Information System (INIS)

    When temperature is increased, the various phenomena that occur in a saturated natural potential host clay for nuclear waste disposal (Boom clay from SCK-CEN in Mol, Belgium) were experimentally investigated in a temperature controlled high stress triaxial cell. Firstly, the pore pressure build-up due to the difference in thermal dilation of both water and minerals was investigated through thermal consolidation tests. Interesting information was obtained about the dissipation of thermally induced pore pressure in Boom clay, based on the standard Terzaghi consolidation theory. Secondly, the volume change behaviour in drained conditions (i.e. under a very slow temperature increase) confirmed that the clay overconsolidation ratio (OCR) controlled the nature of the volume changes. Whereas overconsolidated soils use to dilate as any material when temperature is elevated, normally consolidated soils present a decrease in volume, which is less common. The principles of a coupled thermo-elasto-plastic model that was specifically developed to model this particular behaviour are finally presented. Obviously, it appears necessary to account in detail for these thermal phenomena in order to properly understand the response of the geological barrier in the near field once nuclear waste has been stored. (orig.)

  11. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (Volume 1)

    International Nuclear Information System (INIS)

    The results of two years of research on thermomechanics of clays performed within CEC contract Fl1W/0150 are described herein. Previous studies (research contracts with CEC/WAS/380.83.7 l) performed by ISMES have evidenced the need for an improved modelling of the volumetric response of natural clays. In a coupled approach, this leads to an improved prediction of pore-pressure development and dissipation. This is crucial for assessing conditions of a possible local thermal failure as verified in laboratory tests done at ISMES. The first part of the study lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton. It consists in: (a) developing a framework for inclusion of water/soil particle thermally induced interaction into a thermodynamically consistent mixture theory approach (Section 2); (b) studying possible modelling approaches of considering the effective thermal expansion coefficient of pore water dependency on pore water status (Section 2); (c) testing artificial clays to assess pore water thermal expansion dependence on temperature in the presence of different amounts of active clay minerals and also Boom clay (Section 3); (d) performing a laboratory test campaign on Boom clay with special attention to the response in the overconsolidated domain (Section 4). 89 figs., 18 tabs., 102 refs

  12. Estimation of land subsidence caused by loss of smectite-interlayer water in shallow aquifer systems

    Science.gov (United States)

    Liu, Chen-Wuing; Lin, Wen-Sheng; Cheng, Li-Hsin

    2006-04-01

    Traditionally, land subsidence that results from groundwater over-pumping has often been described by the theory of consolidation. The mechanism of land subsidence due to the dehydration of clay minerals is not well addressed. A model of the “hydration state of smectite”, and a “solid solution model of smectite dehydration”, incorporating a thermodynamic solid solution model and laboratory results concerning clay-water systems of swelling pressure, hydration state and basal spacing in smectite interlayer, are employed to examine the effect of the release of water from the smectite interlayer on land subsidence in the coastal area of the Chou-Shui River alluvial fan and the Yun Lin offshore industrial infrastructure complex in Taiwan. The results indicate that 9.56-22.80% of the total cumulative land subsidence to a depth of 300 m is consistent with smectite dehydration following the over-pumping of groundwater. This dehydration-related land subsidence occurred to a depth of 0-60 m, with subsidence due to smectite dehydration accounting for 6.20-13.32% of the primary consolidation. Additionally, the total amount of subsidence resulting from both smectite dehydration and primary consolidation is consistent with the subsidence observed in the field. This study reveals that smectite dehydration appears to be important in assessing and predicting land subsidence in shallow aquifer systems.

  13. Experimental study on the hydro-mechanical coupling behaviour of highly compacted expansive clay

    OpenAIRE

    Tang, Anh-Minh; Cui, Yu-Jun

    2010-01-01

    Highly compacted expansive clays have been usually considered as a possible material for sealing and backfill in deep geological disposal of radioactive waste. In this condition, the material is simultaneously subjected to water infiltration from the geological barrier and stresses generated by the swelling of engineered barriers in confined conditions. Its behaviour under hydro-mechanical loading is essential to the safe design of the whole storage system. In the present work, MX80 bentonite...

  14. Improvement of Hydraulic System Blast Furnace Clay Gun%高炉泥炮液压系统改造

    Institute of Scientific and Technical Information of China (English)

    唐辉

    2015-01-01

    高炉泥炮是高炉生产的重点设备之一,本文介绍了高炉泥炮液压系统的构成及存在的问题。通过液压站静压导轨伸缩防护罩改造和位移传感器的定位优化,保证了高炉泥炮液压系统的正常运行,为高炉的稳定顺行创造了良好的条件。%Blast furnace mud gun was one of the key equipment of blast furnace.The paper introduced the composition of hydraulic system for blast furnace mud gun and the existing problems.Hydrostatic guide way telescopic protective cover positioning transformation and the displacement sensor was optimized through the hydraulic station to ensure the normal op-eration of the hydraulic system of blast furnace mud gun and create good conditions for the stable operation of blast furnace.

  15. Environmental Control and Life Support System, Water Recovery System

    Science.gov (United States)

    2000-01-01

    The Environmental Control and Life Support System (ECLSS) Group of the Flight Projects Directorate at the Marshall Space Flight Center (MSFC) is responsible for designing and building the life support systems that will provide the crew of the International Space Station (ISS) a comfortable environment in which to live and work. This is a close-up view of ECLSS Water Recovery System (WRS) racks. The MSFC's ECLSS Group overseas much of the development of the hardware that will allow a constant supply of clean water for four to six crewmembers aboard the ISS. The WRS provides clean water through the reclamation of wastewaters, including water obtained from the Space Shuttle's fuel cells, crewmember urine, used shower, handwash and oral hygiene water cabin humidity condensate, and Extravehicular Activity (EVA) wastes. The WRS is comprised of a Urine Processor Assembly (UPA), and a Water Processor Assembly (WPA). The UPA accepts and processes pretreated crewmember urine to allow it to be processed along with other wastewaters in the WPA, which removes free gas, organic, and nonorganic constituents before the water goes through a series of multifiltration beds for further purification. Product water quality is monitored primarily through conductivity measurements. Unacceptable water is sent back through the WPA for reprocessing. Clean water is sent to a storage tank. The water must meet stringent purity standards before consumption by the crew. The UPA provided by the MSFC and the WRA is provided by the prime contractor, Hamilton Sundstrand Space Systems, International (HSSSI) from Cornecticut.

  16. Iodide Sorption to Clays and the Relationship to Surface Charge and Clay Texture - 12356

    International Nuclear Information System (INIS)

    Iodine is assumed to behave conservatively in clay barriers around nuclear waste repositories and in natural sediments. Batch experiments tend to show little to no sorption, while in column experiments iodine is often retarded relative to tritiated water. Current surface complexation theory cannot account for negatively charged ion sorption to a negatively charged clay particle. Surface protonation and iodide sorption to clay minerals were examined using surface titrations and batch sorption experiments with a suite of clay minerals. Surface titrations were completed spanning a range of both pH values and ionic strengths. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were deconvoluted to attain the pKa distribution for each material at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly variable between the different minerals and as a function of ionic strength. Iodide sorption experiments were completed at high solid:solution ratios to exacerbate sorption properties. Palygorskite and kaolinite had the highest amount of iodide sorption and montmorillonite had the least. (authors)

  17. Characterization of clay minerals; Caracterizacion de minerales arcillosos

    Energy Technology Data Exchange (ETDEWEB)

    Diaz N, C.; Olguin, M.T.; Solache R, M.; Alarcon H, T.; Aguilar E, A. [Gerencia de Ciencias Basicas, Direccion de Investigacion Cientifica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The natural clays are the more abundant minerals on the crust. They are used for making diverse industrial products. Due to the adsorption and ion exchange properties of these, a great interest for developing research directed toward the use of natural clays for the waste water treatment has been aroused. As part of such researches it is very important to carry out previously the characterization of the interest materials. In this work the results of the mineral and elemental chemical composition are presented as well as the morphological characteristics of clay minerals from different regions of the Mexican Republic. (Author)

  18. Surface Waters Information Management System (SWIMS)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Surface Waters Information Management System (SWIMS) has been designed to meet multi-agency hydrologic database needs for Kansas. The SWIMS project was...

  19. Cation exchange and adsorption on clays and clay minerals

    OpenAIRE

    Ammann, Lars

    2003-01-01

    The specific surface area of a clay mineral comprises the external and internal surface area and, finally, the surface area which is exposed to the solution (Chap. 6.1). The aim of this study was to correlate adsorption data of common clays with these specific surface areas.

  20. Euroclay 95. Clays and clay materials sciences. Book of abstracts

    International Nuclear Information System (INIS)

    The document contains the abstracts of the invited lecturers (18) and posters (247) presented at EUROCLAY '95. Clays and clay materials sciences. 13 items (4 from the invited lecturers and 12 from posters) have been considered within the INIS Subject Scope and indexed separately

  1. THE INFLUENCE OF POTASSIUM CHLORIDE ON THE REINFORCED MARINE CLAY FOR FOUNDATION SOIL BEDS

    Directory of Open Access Journals (Sweden)

    Koteswara Rao,

    2011-04-01

    Full Text Available Weak marine soil deposits have been found both on the coast and in several offshore areas spread over many parts of the world. When clay particles precipitate in salt water, there is a tendency for the clayparticles to flocculate and stick together giving rise to some sort of edge-to-face arrangement. As a result, clay, silt, and fine sand particles settle almost at the same rate and the final sediment formed consists of particles with a very loose card house-like structure. Hence the marine sediments can be considered loose sediments, usually formed with high void ratios. Problems are associated with these fine-grained soils deposited at a soft consistency. Fine-grained soils are very sensitive to changes in the stress system, moisture content and system chemistry of the pore fluid. In addition to these, the problems arising out ofhigh compressibility and low shear strength of these weak marine deposits expose geotechnical engineers to considerable changes in the construction of various coastal and offshore structures. In this present investigation, the performance of the potassium chloride on the strength characteristics of the marine clay has been studied and also the reinforcement effect on the improvement of load bearing capacity of the KCl treated marine clay has been studied.

  2. Preparation and characterization of bentonite organo clay; Preparacao de caracterizacao de argilas bentonitas organofilicas

    Energy Technology Data Exchange (ETDEWEB)

    Bertagnolli, C.; Almeida Neto, A.F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica. Lab. de Engenharia Ambiental; Silva, M.G.C., E-mail: meuris@feq.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica

    2009-07-01

    Bentonite clays organically modified have great potential use for environmental remediation, especially in the separation of organic compounds from the water. The aim of this work was the preparation of organophilic clays from 'Verde-Lodo' bentonite clay with the quaternary ammonium salts cetyl-pyridinium chloride and benzalkonium chloride. The materials obtained were characterized by XRD, thermogravimetric analyses, Helium picnometry, SEM and energy dispersive X-ray techniques. The results show consistently successful synthesis of the organoclay through the increase in the basal spacing, as well as salt elimination picks and presence of carbon and chlorine in the modified clays; they are inexistent elements in the natural clay. (author)

  3. Cyclic Shearing Deformation Behavior of Saturated Clays

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests under unconsolidated-undrained conditions. Through a series of tests on saturated clay, the effects of initial shear stress and stress reversal on the clay's strain-stress behavior are examined, and the behavior of pore water pressure is studied. The experimental results indicate that the patterns of stress-strain relations are distinctly influenced by the initial shear stress in the cyclic single-direction shear tests. When the initial shear stress is large and no stress reversal occurs, the predominant deformation behavior is characterized by an accumulative effect. When the initial shear stress is zero and symmetrical cyclic stress occurs, the predominant deformation behavior is characterized by a cyclic effect. The pore water pressure fluctuates around the confining pressure with the increase of cycle number. It seems that the fluctuating amplitude increases with the increase of the cyclic stress. But a buildup of pore water pressure does not occur. The deformations of clay samples under the complex initial and the cyclic coupled stress conditions include the normal deviatoric deformation and horizontal shear deformation, the average deformation and cyclic deformation. A general strain failure criterion taking into account these deformations is recommended and is proved more stable and suitable compared to the strain failure criteria currently used.

  4. Enhance decarboxylation reaction of carboxylic acids in clay minerals

    International Nuclear Information System (INIS)

    Clay minerals are important constituents of the Earth's crust. These minerals catalyze reactions in several ways: by energy transfer processes, redox reactions, stabilization of intermediates and by Broensted or Lewis acidity behavior. Important set of organic reactions can be improved in the precedence of clay minerals. Besides the properties of clays to catalyze chemical reactions, it is possible to enhance some of its reactions by using ionizing radiation. The phenomenon of radiation-induced catalysis may be connected with ionizing process in the solid and with the trapped non-equilibrium charge carriers. In this paper we are reporting the decarboxylation reaction of carboxylic acids catalyzed by clay and by irradiation of the system acid-clay. We studied the behaviour of several carboxylic acids and analyzed them by gas chromatography, X-ray and infrared spectroscopy. The results showed that decarboxylation of the target compound is the dominating pathway. The reaction is enhanced by gamma radiation in several orders of magnitude. (author)

  5. Study on hydrodynamics associated with quality of water in water distribution system

    Institute of Scientific and Technical Information of China (English)

    李欣; 顾大明; 赵洪宾; 袁一星

    2002-01-01

    The quality of water in water distribution system may vary with both location and time. Water quality models were used to predict spatial and temporal variation of water quality throughout the water system. Before analyzing the variations of water quality, it is necessary to determine the hydrodynamics in water distribution system. Analytical methods for the flow path from water sources to the observed point and water age of every observed node are proposed. This paper makes a further study on water supply route of multi-sources water supply network system. These studies have been applied to an actual water distribution system.

  6. Hydro static water level systems at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Volk, J.T.; Guerra, J.A.; Hansen, S.U.; Kiper, T.E.; Jostlein, H.; Shiltsev, V.; Chupyra, A.; Kondaurov, M.; Singatulin, S.

    2006-09-01

    Several Hydrostatic Water Leveling systems (HLS) are in use at Fermilab. Three systems are used to monitor quadrupoles in the Tevatron and two systems are used to monitor ground motion for potential sites for the International Linear Collider (ILC). All systems use capacitive sensors to determine the water level of water in a pool. These pools are connected with tubing so that relative vertical shifts between sensors can be determined. There are low beta quadrupoles at the B0 and D0 interaction regions of Tevatron accelerator. These quadrupoles use BINP designed and built sensors and have a resolution of 1 micron. All regular lattice superconducting quadrupoles (a total of 204) in the Tevatron use a Fermilab designed system and have a resolution of 6 microns. Data on quadrupole motion due to quenches, changes in temperature will be presented. In addition data for ground motion for ILC studies caused by natural and cultural factors will be presented.

  7. Laboratory measurements of selected optical, physical, chemical, and remote-sensing properties of five water mixtures containing Calvert clay and a nonfluorescing dye

    Science.gov (United States)

    Usry, J. W.; Whitlock, C. H.; Poole, L. R.; Witte, W. G., Jr.

    1981-01-01

    Total suspended solids concentrations ranged from 6.1 ppm to 24.3 ppm and sizes ranged between 1.5 micrometers and 10 micrometers with the most frequently occurring size less than 2 micrometers. Iron concentration was less than 1 percent of the total suspended solids. Nonfluorescing dye concentrations of the two mixtures were 20 ppm and 40 ppm. Attenuation coefficient for the five mixtures ranged from 4.8/m to 21.3/m. Variations in volume scattering function with phase angle were typical. Variations in attenuation and absorption coefficient with wavelength were similar for the mixtures without the dye. Attenuation coefficient of the mixtures with the dye increased for wavelengths less than 600 nm due to the dye's strong absorption peak near 500 nm. Reflectance increased as the concentration of Calvert clay increased and peaked near 600 nm. The nonfluorescent dye decreased the magnitude of the peak, but had practically no effect on the variation for wavelengths greater than 640 nm. At wavelengths less than 600 nm, the spectral variations of the mixtures with the dye were significantly different from those mixtures without the dye.

  8. A novel tracer technique for the assessment of fine sediment dynamics in urban water management systems.

    Science.gov (United States)

    Spencer, K L; Droppo, I G; He, C; Grapentine, L; Exall, K

    2011-04-01

    Urban storm water run off can reduce the quality of receiving waters due to high sediment load and associated sediment-bound contaminants. Consequently, urban water management systems, such as detention ponds, that both modify water quantity through storage and improve water quality through sediment retention are frequently-used best management practices. To manage such systems effectively and to improve their efficiency, there is a need to understand the dynamics (transport and settling) of sediment, and in particular the fine sediment fraction (modelling the transport behaviour of fine-grained and cohesive sediment is problematic and field-based measurements can be costly, time-consuming and unrepresentative. The aim of this study was to test the application of a novel cohesive sediment tracer and to determine fine sediment transport dynamics within a storm water detention pond. The cohesive sediment tracer used was a holmium labelled montmorillonite clay which flocculated and had similar size and settling velocity to the natural pond sediment it was intended to mimic. The tracer demonstrated that fine sediment was deposited across the entire pond, with the presence of reed beds and water depth being important factors for maximising sediment retention. The results of the sediment tracer experiment were in good agreement with those of a mathematical sediment transport model. Here, the deposited sediment tracer was sampled by collecting and analysing surface pond sediments for holmium. However, analysis and sampling of the three dimensional suspended tracer 'cloud' may provide more accurate information regarding internal pond sediment dynamics. PMID:21420140

  9. Modeling water uptake by a root system growing in a fixed soil volume

    CERN Document Server

    Albrieu, J L Blengino; Tarzia, D A

    2015-01-01

    The water uptake by roots of plants is examined for an ideal situation, with an approximation that resembles plants growing in pots, meaning that the total soil volume is fixed. We propose a coupled water uptake-root growth model. A one-dimensional model for water flux and water uptake by a root system growing uniformly distributed in the soil is presented, and the Van Genuchten model for the transport of water in soil is used. The governing equations are represented by a moving boundary model for which the root length, as a function of time, is prescribed. The solution of the model is obtained by front-fixing and finite element methods. Model predictions for water uptake by a same plant growing in loam, silt and clay soils are obtained and compared. A sensitivity analysis to determine relative effects on water uptake when system parameters are changed is also presented and shows that the model and numerical method proposed are more sensitive to the root growth rate than to the rest of the parameters. This se...

  10. Upgrades to the ISS Water Recovery System

    Science.gov (United States)

    Kayatin, Matthew J.; Carter, Donald L.; Schunk, Richard G.; Pruitt, Jennifer M.

    2016-01-01

    The International Space Station Water Recovery System (WRS) is comprised of the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WRS produces potable water from a combination of crew urine (first processed through the UPA), crew latent, and Sabatier product water. Though the WRS has performed well since operations began in November 2008, several modifications have been identified to improve the overall system performance. These modifications can reduce resupply and improve overall system reliability, which is beneficial for the ongoing ISS mission as well as for future NASA manned missions. The following paper details efforts to reduce the resupply mass of the WPA Multifiltration Bed, develop improved catalyst for the WPA Catalytic Reactor, evaluate optimum operation of UPA through parametric testing, and improve reliability of the UPA fluids pump and Distillation Assembly.

  11. Hanford 200 area (sanitary) waste water system

    International Nuclear Information System (INIS)

    The US Department of Energy (DOE) Hanford Site is located in southeastern Washington State. The Hanford Site is approximately 1,450 sq. km (560 sq. mi) of semiarid land set aside for activities of the DOE. The reactor fuel processing and waste management facilities are located in the 200 Areas. Over the last 50 years at Hanford dicard of hazardous and sanitary waste water has resulted in billions of liters of waste water discharged to the ground. As part of the TPA, discharges of hazardous waste water to the ground and waters of Washington State are to be eliminated in 1995. Currently sanitary waste water from the 200 Area Plateau is handled with on-site septic tank and subsurface disposal systems, many of which were constructed in the 1940s and most do not meet current standards. Features unique to the proposed new sanitary waste water handling systems include: (1) cost effective operation of the treatment system as evaporative lagoons with state-of-the-art liner systems, and (2) routing collection lines to avoid historic contamination zones. The paper focuses on the challenges met in planning and designing the collection system

  12. Experimental study of thermo-hydro-mechanical behaviour of Callovo-Oxfordian Clay-stone

    International Nuclear Information System (INIS)

    compression tests at elevated temperature (80 C): the effects of temperature on the behaviour of Clay-stone and thermal pressurization. A drained heating test under in-situ stress conditions evidenced, probably for first time, a plastic contractant response of the Clay-stone (like normally consolidated clays), a feature not considered in the presently conducted numerical modelling of deep disposal systems. Another new important observed feature is the increase in drained compressibility of the COx Clay-stone with temperature, not observed in clays. The investigation of thermal pressurization (caused by the low Clay-stone permeability and by the significant difference in thermal expansion between water and the solid phase) has been carried out by means of undrained heating tests, after a detailed analysis of the major effects of the measurement system (which should perhaps be also analyzed when performing in-situ measurements). The thermal pressurization coefficient appeared to be quite sensitive to changes in temperature and stress, it decreased between 0.14 and 0.1 MPa/C between 25 and 80 C. It is believed that the different thermo-hydro-mechanical volumetric responses obtained here allow a better interpretation and modelling of the behaviour of the Clay-stone formation around the galleries in areas that are mostly saturated, except close to the galleries (a few decimetres). (author)

  13. Clay resources in the Netherlands

    NARCIS (Netherlands)

    Meulen, M.J. van der; Maljers, D.; Gessel, S.F. van; Gruijters, S.H.L.L.

    2007-01-01

    Clay is a common lithology in the Dutch shallow subsurface. It is used in earth constructions such as dikes, and as raw material for the fabrication of bricks, roof tiles etc. We present a new national assessment of Dutch clay resources, as part of a project that provides mineral-occurrence informat

  14. Clay resources in the Netherlands

    NARCIS (Netherlands)

    Meulen, M.J. van der; Maljers, D.; Gessel, S.F. van; Gruijters, S.H.L.L.

    2007-01-01

    Clay is a common lithology in the Dutch shallow subsurface. It is used in earth constructions such as dikes, and as raw material for the fabricationof bricks, roof tiles etc. We present a new national assessment of Dutch clay resources, as part of a project that provides mineral-occurrenceinformatio

  15. Strength Properties of Aalborg Clay

    DEFF Research Database (Denmark)

    Iversen, Kirsten Malte; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    In the northern part of Vendsyssel, Denmark, the deposits made in the late glacial time are formed by the sea. The deposits are named after two mussels: Yoldia clay and Saxicava sand. However, in the southern part of Vendsyssel and in the area of Aalborg the clay and sand deposits from the late g...

  16. A mechanism of basal spacing reduction in sodium smectitic clay materials in contact with DNAPL wastes.

    Science.gov (United States)

    Ayral-Cinar, Derya; Otero-Diaz, Margarita; Demond, Avery H

    2016-09-01

    There has been concern regarding the possible attack of clays in aquitards, slurry walls and landfill liners by dense nonaqueous phase liquid (DNAPL) wastes, resulting in cracking. Despite the fact that a reduction in basal spacing in sodium smectitic clay materials has been linked to cracking, no plausible mechanism by which this reduction occurs in contact with waste DNAPLs has been formulated. To elucidate a mechanism, screening studies were conducted that showed that the combination of an anionic surfactant (AOT), a nonionic surfactant (TritonX-100) and a chlorinated solvent, tetrachloroethylene (PCE), could replicate the basal spacing reduction and cracking behavior of water-saturated bentonite caused by two waste DNAPLs obtained from the field. FTIR measurements of this system showed a displacement of the HOH bending band of water symptomatic of desiccation. Sorption measurements showed that the uptake of AOT by bentonite increased eight fold in the presence of TritonX-100 and PCE. The evidence presented here supports a mechanism of syneresis, involving the extraction of water from the interlayer space of the clay through the synergistic sorption of a nonionic and anionic surfactant mixture. It is speculated that the solvation of water in reverse micellar aggregates is the process driving the syneresis.

  17. Clay minerals in pollution control

    Energy Technology Data Exchange (ETDEWEB)

    Tateo, F. [Consiglio Nazionale delle Ricerche, Istituto di Ricerca sulle Argille, Tito Scalo, PZ (Italy)

    2000-07-01

    Clay minerals are fundamental constituents of life, not only as possible actors in the development of life on the Earth (Cairns-Smith and Hartman, 1986), but mainly because they are essential constituents of soils, the interface between the solid planet and the continental biosphere. Many, many authors have devoted themselves to the study of clays and clay minerals since the publication of the early modern studies by Grim (1953, 1962) and Millot (1964). In those years two very important associations were established in Europe (Association Internationale pour l'Etude des Argiles, AIPEA) and in the USA (Clay Mineral Society, CMS). The importance of these societies is to put together people that work in very different fields (agronomy, geology, geochemistry, industry, etc.), but with a common language (clays), very useful in scientific work. Currently excellent texts are being published, but introductory notes are also available on the web (Schroeder, 1998).

  18. Space Station Freedom regenerative water recovery system configuration selection

    Science.gov (United States)

    Reysa, R.; Edwards, J.

    1991-01-01

    The Space Station Freedom (SSF) must recover water from various waste water sources to reduce 90 day water resupply demands for a four/eight person crew. The water recovery system options considered are summarized together with system configuration merits and demerits, resource advantages and disadvantages, and water quality considerations used to select the SSF water recovery system.

  19. TORR system polishes oily water clean

    International Nuclear Information System (INIS)

    The TORR (total oil recovery and remediation) system utilizes a specially patented polymer material, similar to styrofoam, which is used to get rid of non-soluble hydrocarbons from water. An application in Fort Smith, Northwest Territories, is described where it was used to recover diesel oil, which had been seeping into the groundwater over a period of 20 years. About 100,000 gallons of heating oil had leached into the water; TORR removed the non-soluble hydrocarbons, while another piece of equipment removed the soluble portions. After treatment the water tested consistently at non-detectable levels and was clean enough to be discharged into the town's sewer system. The system is considered ideal for oil spills clean-up underground, onshore, or the open sea, but it also has many potentially useful applications in industrial and oilfield applications. Water used in steam injection and water floods to produce heavy oil and SAGD applications are some of the obvious ones that come to mind. Cleaning up the huge tailings ponds at the mining and processing of oil sands, and removing diluent from water that is used to thin out bitumen in pipelines so that it can be transported to processing plants, are other promising areas of application. Several field trials to test the effectiveness of the system in these type of applications are scheduled for the summer and fall of 2002

  20. Preparation and properties of biodegradable starch–clay nanocomposites

    KAUST Repository

    Chung, Yi-Lin

    2010-01-01

    Well-dispersed starch-clay nanocomposites were prepared by adding a dilute clay dispersion to a solution of starch followed by coprecipitation in ethanol. The clay didn\\'t significantly influence the type of crystalline structure of starch molecules although the amount of crystallinity appears to be somewhat lower in the nanocomposites. The nanocomposites show improved modulus and strength without a decrease in elongation at break. The increase in modulus and strength is 65% and 30%, respectively for the nanocomposite containing 5 wt.% clay compared to the unfilled starch materials. Further increases in clay result in deterioration in properties most likely due to poorer clay dispersion and lower polymer crystallinity. As the amount of water increases, the modulus of both pure starch and starch nanocomposites decreases, although the change is less pronounced in the nanocomposites suggesting that the addition of clay to form nanocomposites can improve the stability of starch-based products during transportation and storage. © 2009 Elsevier Ltd. All rights reserved.

  1. Development and Characterisation of Nanoclays from Indian Clays

    Directory of Open Access Journals (Sweden)

    S. Manocha

    2008-07-01

    Full Text Available Indian clays are known for their smecticity. One such clay sample collected from Bhuj (Gujaratwas characterised and modified by successive sedimentation processes for different time intervals.The non-plastic components of clay, viz., quartz, illite, iron oxide, CaO, MgO, and organic matterwere removed in different steps, as the heavy impurities in the clay-water suspensions, settledown during sedimentation. The free iron oxide present in clay suspension was reduced bygiving sodium citrate-bicarbonate-dithionite treatment and iron content was further reducedfrom 12Œ15 per cent to 5Œ7 per cent respectively. The organic matter was removed by sodiumacetate-H2O2 treatment. The modified clay so obtained was characterised by thermal analysis,FTIR, and XRD,  SEM and TEM. The cation exchange capacities of original and modified clayswere determined both by methylene blue method and ammonium acetate method. The cationex change capacity is found to enhance from 120Œ130 meq/100 g to 135Œ145 meq/100 g. Usingthe above procedure, 92 per cent smecticity was obtained. Organo philisation of purified clay(smectite was carried out by intercalation with alkyl ammonium salt. The  XRD  analysis show edenhancement of interlamellar spacing from 1.294 nm to 2.855 nm.Defence Science Journal, 2008, 58(4, pp.517-524, DOI:http://dx.doi.org/10.14429/dsj.58.1672

  2. Darcian preferential water flow and solute transport through bimodal porous systems: experiments and modelling.

    Science.gov (United States)

    Coppola, Antonio; Comegna, Vincenzo; Basile, Angelo; Lamaddalena, Nicola; Severino, Gerardo

    2009-02-16

    Soils often exhibit a variety of small-scale heterogeneities such as inter-aggregate pores and voids which partition flow into separate regions. In this paper a methodological approach is discussed for characterizing the hydrological behaviour of a heterogeneous clayey-sandy soil in the presence of structural inter-aggregate pores. For the clay soil examined, it was demonstrated that, coupling the transfer function approach for analyzing BTCs and water retention data obtained with different methods from laboratory studies captures the bimodal geometry of the porous system along with the related existence of fast and slow flow paths. To be effectively and reliably applied this approach requires that the predominant effects of the soil hydrological behaviour near saturation be supported by accurate experimental data of both breakthrough curves (BTCs) and hydraulic functions for high water content values. This would allow the separation of flow phases and hence accurate identification of the processes and related parameters. PMID:19042056

  3. Validation of a kinetic-diffusive model to characterize pozzolanic reaction kinetics in sugar cane straw-clay ash/lime systems

    Directory of Open Access Journals (Sweden)

    Villar-Cociña, E.

    2005-06-01

    Full Text Available A kinetic-diffusive model proposed by the authors in previous papers to describe pozzolanic reaction kinetics in sugar cane straw-clay ash (SCSCA/calcium hydroxide (CH systems is validated in this study. Two different methods (direct and indirect for determining pozzolanic activity were applied and their effect on pozzolanic reaction rate kinetic constants evaluated. Determined by fitting a model to the data, these constants are used to quantitatively characterize pozzolanic activity. The values of the kinetic constants calculated with the model were similar for the two methods. Classic kinetic models, such as the Jander, modified Jander and Zhuravlev models, were also applied to the system studied and the results were compared to the figures calculated with the model proposed. The kinetic-diffusive approach proposed was found to be valid regardless of the method for determining pozzolanic activity used, and to be the most suitable model for describing pozzolanic reaction kinetics in the SCSCA/lime system.

    Se valida la aplicación de un modelo cinético-difusivo propuesto por los autores en trabajos anteriores para describir la cinética de reacción puzolánica en sistemas ceniza de paja de caña-arcilla (CPCAñúdróxido de calcio (CH. Se aplican 2 métodos diferentes de actividad puzolánica (directo e indirecto y se valora el efecto que pudieran tener los mismos sobre las constantes cinéticas de velocidad de reacción de la reacción puzolánica. Estas constantes cinéticas son determinadas en el proceso de ajuste del modelo y permiten caracterizar cuantitativamente la actividad puzolánica. Los resultados muestran la similitud de las constantes cinéticas de velocidad de reacción calculadas, aplicando el modelo a los resultados experimentales obtenidos por ambos métodos. Además, fueron aplicados al sistema estudiado modelos cinéticos el chicos como: modelo de Jander, modelo de Jander Modificado y el modelo de Zhuravlev y

  4. Evaluation of some ceramic clays from Zambia

    OpenAIRE

    Mitchell, C J

    1993-01-01

    This reports details the technical evaluation of ceramic clays collected during visits to Zambia in 1990 and 1991 by the author (Clive Mitchell). The clay samples included: Choma kaolin (Southern Province), Twapia kaolin (Copperbelt Province), Kapiri Mposhi kaolin (Central Province), Masenche clay (Northern Province), Leula clay, Misenga clay and Chikankata clay (Southern Province). The Choma kaolin was asessed to be an excellent source of ceramic-grade kaolin. The Twapia and Kapiri Mposhi ka...

  5. Energy optimization of water distribution system

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    In order to analyze pump operating scenarios for the system with the computer model, information on existing pumping equipment and the distribution system was collected. The information includes the following: component description and design criteria for line booster stations, booster stations with reservoirs, and high lift pumps at the water treatment plants; daily operations data for 1988; annual reports from fiscal year 1987/1988 to fiscal year 1991/1992; and a 1985 calibrated KYPIPE computer model of DWSD`s water distribution system which included input data for the maximum hour and average day demands on the system for that year. This information has been used to produce the inventory database of the system and will be used to develop the computer program to analyze the system.

  6. Biologically-Inspired Water Propulsion System

    Institute of Scientific and Technical Information of China (English)

    Andrzej Sioma

    2013-01-01

    Most propulsion systems of vehicles travelling in the aquatic environment are equipped with propellers.Observations of nature,however,show that the absolute majority of organisms travel through water using wave motion,paddling or using water jet power.Inspired by these observations of nature,an innovative propulsion system working in aquatic environment was developed.This paper presents the design of the water propulsion system.Particular attention was paid to the use of paddling techniques and water jet power.A group of organisms that use those mechanisms to travel through water was selected and analysed.The results of research were used in the design of a propulsion system modelled simultaneously on two methods of movement in the aquatic environment.A method for modelling a propulsion system using a combination of the two solutions and the result were described.A conceptual design and a prototype constructed based on the solution were presented.With respect to the solution developed,studies and analyses of selected parameters of the prototype were described.

  7. Alternative Electrochemical Systems for Ozonation of Water

    Science.gov (United States)

    Andrews, Craig C.; Murphy, Oliver J.

    2003-01-01

    Electrochemical systems that are especially well suited for the small-scale generation of ozone and ozonated water for local use have been invented. These systems can operate with very little maintenance, and the only inputs needed during operation are electric power and water. Ozonated water produced by these systems can be used in diverse industrial applications: A few examples include sterilization in the brewing industry, general disinfection, and treatment of sewage and recycled water. The basic principle of operation admits of several alternative system configurations. The heart of the system is a stack of electrolytic cells, each containing a proton-exchange membrane (which serves as a solid electrolyte) sandwiched between a catalytic anode and a catalytic cathode. Preferably, the proton-exchange membrane is made of a perfluorinated sulfonic acid polymer. During electrolysis, a mixture of O2 and O3 gases is generated at the anode and H2 is generated at the cathode. Some of the O3 generated at the anode becomes dissolved in the water. The proportion of O3 in the O2/O3 mixture can be maximized by the selection of suitable electrode materials and the use of a high overpotential. Although the proton-exchange membrane conducts protons, it does not conduct electrons. It is also impermeable by gases; consequently, it maintains separation between the O2/O3 mixture evolved at the anode and the H2 evolved at the cathode.

  8. Transmission X-ray Microscopy—A New Tool in Clay Mineral Floccules Characterization

    Directory of Open Access Journals (Sweden)

    Ray L. Frost

    2012-10-01

    Full Text Available Effective flocculation and dewatering of mineral processing streams containing clays are microstructure dependent in clay-water systems. Initial clay flocculation is crucial in the design and for the development of a new methodology of gas exploitation. Microstructural engineering of clay aggregates using covalent cations and Keggin macromolecules have been monitored using the new state of the art Transmission X-ray Microscope (TXM with 60 nm tomography resolution installed in a Taiwanese synchrotron. The 3-D reconstructions from TXM images show complex aggregation structures in montmorillonite aqueous suspensions after treatment with Na+, Ca2+ and Al13 Keggin macromolecules. Na-montmorillonite displays elongated, parallel, well-orientated and closed-void cellular networks, 0.5–3 µm in diameter. After treatment by covalent cations, the coagulated structure displays much smaller, randomly orientated and openly connected cells, 300–600 nm in diameter. The average distances measured between montmorillonite sheets was around 450 nm, which is less than half of the cell dimension measured in Na-montmorillonite. The most dramatic structural changes were observed after treatment by Al13 Keggin; aggregates then became arranged in compacted domains of a 300 nm average diameter composed of thick face-to-face oriented sheets, which forms porous aggregates with larger intra-aggregate open and connected voids.

  9. Organics. [Nature and analysis of chemical species in water systems

    Energy Technology Data Exchange (ETDEWEB)

    DeWalle, F.B. (Univ. of Washington, Seattle); Lo, C.; Sung, J.; Kalman, D.; Chian, E.S.K.; Giabbai, M.; Ghosal, M.

    1982-01-01

    This literature review presents an overview of nonspecific methods, followed by group and compound specific methods used in the analysis of detergents, aliphatic and aromatic hydrocarbons, pesticides and herbicides, and in process and industrially related compounds. Many studies are focused on polychlorinated biphenyls (PCB) because of their persistant character in nature even after a substantial decrease in usage. Their presence in sediments is correlated with organic matter and clay owing to their adsorption to these materials. They are also observed in effluents from combustion processes and in sludges from treatment units. Bacteria have been identified that degrade PCBs and give higher rates than the 1-year turnover rate observed in coastal waters. Industrially derived organics have been detected in surface and ground water, drinking water and waste water. Coal conversion processes can lead to releases of toxic nitrogen-containing compounds such as pyridines and sulfur heterocyclics. Included are 8 tables and 242 references. (JMT)

  10. Regenerable Iodine Water-Disinfection System

    Science.gov (United States)

    Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

    1994-01-01

    Iodinated resin bed for disinfecting water regenerated to extend useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle manually controlled readily automated to start and stop according to signals from concentration sensors. Further benefit of regeneration is bed provides highly concentrated biocide source when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

  11. Prions, Radionuclides and Clays: Impact of clay interlayer "acidity" on toxic compound speciation

    Science.gov (United States)

    Charlet, L.; Hureau, C.; Sobolev, O.; Cuello, G.; Chapron, Y.

    2007-05-01

    The physical and chemical processes that are the basis of contaminant retardation in clay rich medium, such as soil or nuclear waste repository, have been studied at the molecular level by a combination of molecular dynamics (MD), electron paramagnetic spectroscopy (EPR) and neutron diffraction with isotopic substitution (NDIS). The speciation of contaminants such as Sm, a radionuclide analogue, and Cu, bound to Prion protein (PrP), has been studied upon adsorption in clay interlayers. We used as molecular probe the P5-Cu(II) complex, where the P5 pentapeptide(92-96 PrP residues) represents one of the five Cu(II) binding site present in PrP, the key protein involved in diseases known as transmissible spongiform encephalopathies. In both cases, the pH of the interlayer has been inferred from the metal ion coordination, here used as a molecular reporter. In circum neutral pH waters, samarium is present as Sm(OH)3° species and should not be adsorbed in clay interlayer by "cation exchange" unless its hydrolysis is altered. Samarium NDIS results indicate that whether the number of oxygen nearest neighbours varies only from 8.5 to 7, as Sm penetrates the interlayer, the number of hydrogen nearest neighbours drops from 12 to 6. The high affinity of clay for Sm shows that a change in Sm hydrolysis occurs in the clay interlayer, but is directly followed by the formation of a surface complex with montmorillonite siloxane plane functional groups which prevents the determination of a "local pH". Conversely, has been found to be a much more sensitive interlayer water pH probe. and this peptide domain is involved in the misfolding of the protein,a transconformation which may lead to the pathogenic PrPSc form. We have therefore studied by EPR spectroscopy the adsorption of Cu(II)-P5 complexes on montmorillonite, and found the clay to have a large and selective adsorption capacity for the various [Cu(P5)H-n](2-n)+ complexes where n is the number of deprotonated amido function

  12. Characteristics of Trihalomethanes in Water Distribution System

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming; ZHANG Jie; ZHANG Xin-yu; ZHENG Shuang-ying; LI Xin

    2008-01-01

    To investigate the characteristics of disinfection by-products (DBPs) in an actual water distribution system using the raw water with high bromide ion concentration, the composition and concentration of trihalomethanes (THMs) formed by chlorination of the water in the presence of bromide ion were measured in a city water distribution system during one year. The results show that brominated THMs contributed a great part (83%89%) to the index for additive toxicity (ATI) and resulted in the ATI of most of the samples exceeding WHO guideline standard for total THMs (TTHMs), especially during the summer (rainy season). This indicates that the chlorination of water in the presence of bromide ion leaded to high ratios of brominated THMs to TTHMs. However, a visible increase in the concentration of THMs with increasing residence time in the distribution system was not observed. Additionally, based on alternatives analysis, packed tower aeration method is proposed to reduce THMs level of the finished water leaving the treatment plant.

  13. Time and frequency GPR waveforms analysis for clay content evaluation in soils

    Science.gov (United States)

    Tosti, F.; Patriarca, C.

    2012-04-01

    The mechanical behaviour of soils is partly affected by their clay content, which exerts some considerable effects in many applications in the fields of civil engineering, geology and environmental engineering. This study focuses on pavement engineering, but the approach can be extended to other purposes. The presence of clay in the bearing structural layers of pavements frequently causes damages and defects, such as transversal and longitudinal cracks, deformations and rutting. Consequently, the road safety and operability decrease, while the expected number of accidents increases. In this work Ground Penetrating Radar (GPR) laboratory inspections are carried out in order to predict the presence of clay in pavement structural layers. Data are post-processed in the frequency domain, according to the Rayleigh scattering method based on the Fresnel theory. This new technique can be supported by other survey methods, improving the quality of the results. Analysis are carried out using two different GPR systems. A Radar is used with ground-coupled antennae in a bistatic configuration and common offset; the transmitter and receiver are linked by optic fiber electronic modules and operate at 500 MHz central frequency. The received signal is sampled in the time domain at time steps of 7.8125 x 10-2 ns. A Vector Network Analyzer (VNA) acquires ultra-wide band data in a bandwidth from 500 MHz to 3000 MHz. The signal is sampled in the frequency domain with approximately 1.56 MHz frequency steps. A double-ridged broadband horn antenna is connected via a high-quality coaxial cable to the VNA pulse generator and illuminates the analyzed target in a monostatic off-ground configuration. The experimental setting required the use of road material, typically employed for sub-grade and sub-base layers. Three kind of soils, classified as A1, A2, A3 by AASHTO are used and adequately compacted in electrically and hydraulically isolated boxes. Bentonite clay is gradually added from 2% to

  14. Water system microbial check valve development

    Science.gov (United States)

    Colombo, G. V.; Greenley, D. R.; Putnam, D. F.

    1978-01-01

    Development work on a device for the Space Shuttle that will prevent the transfer of viable microorganisms within water systems is described. The device serves as a check valve in that it prevents the transfer or cross-contamination of microorganisms from a nonpotable system into a potable water system when these systems are interconnected. In this regard, the function of the device is similar to that of the air gap found in conventional one gravity systems. The device is essentially a bed of resin material impregnated with iodine. Basic design data for a variety of flow and temperature conditions are presented, together with results of challenging the beds with suspensions of seven microorganisms including aerobes, anaerobes, and spore formers.

  15. Water diffusivity in starch-based systems.

    Science.gov (United States)

    Leslie, R B; Carillo, P J; Chung, T Y; Gilbert, S G; Hayakawa, K; Marousis, S; Saravacos, G D; Solberg, M

    1991-01-01

    The objective of this study was to investigate the influence of structure, and component interactions, on the sorption and transport properties of water in starch-based systems. We compared the effective diffusivity (Deff) of water in two starches, with differing amylose-amylopectin ratios, using either kinetics of water adsorption or analysis of drying curves (water desorption) to estimate Deff. The effect of incorporating small sugar molecules into the granular or gelatinized starch matrices on Deff was measured by drying curve analysis. To investigate the possible mechanisms of water transport, the porosity and microscopic appearance of the samples at different stages of drying were determined. In a complementary study, sorption isotherms and the number of accessible "binding" sites in the starch and starch-sugar systems were determined using gravimetric analysis and inverse gas chromatography (IGC) 'probe analysis'. In the case of the starch-sugar systems, the measurements were made after the components had been 'mechanically mixed', or after more intimate mixing had been achieved by a co-freeze-drying process. The Deff of the starches was found to depend, in a complex way, on the moisture content of the samples. At relatively high moisture contents, the predominant mode of water transport was by liquid diffusion. As the samples became drier, their porosity increased, and the predominant mode of moisture transport was by vapor phase diffusion. As the samples became very dry (less than 10% water content), Deff fell significantly. Incorporation of sugars, in general, led to a reduction of Deff, which was correlated with a corresponding fall in porosity. In agreement with the findings of other workers, for the starches studied, the value of Deff determined from water adsorption measurements was significantly less than Deff determined from water desorption (drying curve analysis). The form of the Deff versus moisture content relationship was, however, independent

  16. Preparation and characterization of biodegradable PLA/organosilylated clay nanocomposites

    Science.gov (United States)

    Olivieri, R.; Di Maio, L.; Scarfato, P.; Incarnato, L.

    2016-05-01

    In this work a new organosilylated clay was successfully synthesized by functionalization of a natural sodium montmorillonite (MMT) by (3-glycidyloxypropyl)trimethoxysilane (GOPTMS). This organosilylated clay was used as nanofiller for preparation, by solvent casting, of poly(lactic acid) nanocomposite systems. Similar systems, containing as nanofiller the commercial Cloisite 30B (i.e. a natural sodium montmorillonite organically modified with alkylammonium salt), were also prepared for comparison. All the obtained nanocomposite films were characterized using several techniques (XRD, permeability and mechanical tensile tests). Obtained results pointed out that nanocomposite system containing the organosilylated clay showed a better intercalation of the polymer chains into the clay layers and a higher improvement of the oxygen barrier properties, when compared to both the neat PLA film and the PLA film loaded with Cloisite 30B.

  17. Gas injection laboratory experiments on Opalinus Clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Understanding gas transport processes is one of the key issues in the assessment of radioactive waste repository performance and is the focus of this research. If the gas production rate (generated by the anaerobic corrosion of the ferrous metal liner) exceeds the rate of diffusion of gas in the host rock pore water, gas would continue to accumulate and pressure increase until it becomes sufficiently large to create pathways. Despite its importance, information at laboratory scale on gas pressure-induced pathways and breakthrough pressures in geological barriers under controlled gas volume rate and stress conditions is rather scarce. To this aim, the present study was started with the following specific objectives. 1) To develop and calibrate an experimental set-up to perform controlled volume-rate gas injection experiments using a high-pressure triaxial cell to apply isotropic/anisotropic stress states. 2) To carry out a series of tests on Opalinus clay OPA samples to study the conditions under which gas breakthrough processes occur, to analyse the influence of the gas injection rate, the stress state, the orientation of rock discontinuities and other relevant hydro-mechanical variables (porosity and degree of saturation); as well as the observation of the induced desaturation (pore water displacement by gas), in-going and outgoing gas fluxes, and aperture and preferential paths created. For example, local desaturation is a critical issue, since previous tests performed on compacted clay barriers evidenced that no significant water displacement occurred inside the specimen, despite the fact that the observed breakthrough pressure appeared to be higher than the air entry pressure of the material. An instrumented high-pressure triaxial cell was used, which was specifically designed to apply isotropic/ anisotropic stress states (up to a maximum of 20 MPa) while injecting gas at controlled volume rate. Each cap of the

  18. Soil Clay Minerals in Namibia and their Significance for the Terrestrial and Marine Past Global Change Research

    OpenAIRE

    HEINE, Klaus; Völkel, Jörg

    2010-01-01

    We delineated seven soil clay mineral provinces in Namibia. Many individual clay mineral assemblages occur in fluvial, pan, cave and other environments. Previous researchers have used clay mineral compositions as evidence for palaeoenvironmental reconstructions, often without analyzing the formation, the transport and the deposition of these clay minerals. In Namibia, rates of erosion and denudation by water and wind have been very small since early Quaternary times. During the Quaternary, th...

  19. Frugivorous bats drink nutrient- and clay-enriched water in the Amazon rain forest: support for a dual function of mineral-lick visits

    OpenAIRE

    Ghanem, Simon J.; Ruppert, Hans; Kunz, Thomas H.; Voigt, Christian C.

    2013-01-01

    In Central Amazonia, large mammals create water-filled puddles when consuming soil. These mineral licks are visited by pregnant and lactating frugivorous bats; possibly for two reasons. Frugivorous bats could supplement their mineral-depleted fruit diet by drinking salty water, or they could buffer dietary plant secondary compounds by consuming soil. We analysed bat fruits from Ecuador and showed that they are depleted in elemental concentrations (Na, K, P) compared with similar f...

  20. Wash water waste pretreatment system study

    Science.gov (United States)

    1976-01-01

    The use of real wash water had no adverse effect on soap removal when an Olive Leaf soap based system was used; 96 percent of the soap was removed using ferric chloride. Numerous chemical agents were evaluated as antifoams for synthetic wash water. Wash water surfactants used included Olive Leaf Soap, Ivory Soap, Neutrogena and Neutrogena Rain Bath Gel, Alipal CO-436, Aerosol 18, Miranol JEM, Palmeto, and Aerosol MA-80. For each type of soapy wash water evaluated, at least one antifoam capable of causing nonpersistent foam was identified. In general, the silicones and the heavy metal ions (i.e., ferric, aluminum, etc.) were the most effective antifoams. Required dosage was in the range of 50 to 200 ppm.

  1. Experimental design applied optimization of a state in epoxy clay dispersion

    International Nuclear Information System (INIS)

    This paper presents some analysis showed that the exfoliation / intercalation of a montmorillonite clay in epoxy resin such as viscosity, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetry (TG). Increasing the viscosity of epoxy resin diglycidyl ether bisphenol A with the addition of clay associated with the sonification system at the time of dispersion is a good indication of exfoliation. The X-ray diffraction already cured composite shows a decrease of crystallinity of clay and EDS microanalysis of SEM, non-uniform dispersion of clay in epoxy resin. Thermal analysis TG composite clay / epoxy shows an increase in thermal stability relative to pure epoxy. (author)

  2. AOIPS water resources data management system

    Science.gov (United States)

    Vanwie, P.

    1977-01-01

    The text and computer-generated displays used to demonstrate the AOIPS (Atmospheric and Oceanographic Information Processing System) water resources data management system are investigated. The system was developed to assist hydrologists in analyzing the physical processes occurring in watersheds. It was designed to alleviate some of the problems encountered while investigating the complex interrelationships of variables such as land-cover type, topography, precipitation, snow melt, surface runoff, evapotranspiration, and streamflow rates. The system has an interactive image processing capability and a color video display to display results as they are obtained.

  3. Modelling water uptake efficiency of root systems

    Science.gov (United States)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  4. Insightful understanding of the role of clay topology on the stability of biomimetic hybrid chitosan-clay thin films and CO2-dried porous aerogel microspheres.

    Science.gov (United States)

    Frindy, Sana; Primo, Ana; Qaiss, Abou El Kacem; Bouhfid, Rachid; Lahcini, Mohamed; Garcia, Hermenegildo; Bousmina, Mosto; El Kadib, Abdelkrim

    2016-08-01

    Three natural clay-based microstructures, namely layered montmorillonite (MMT), nanotubular halloysite (HNT) and micro-fibrillar sepiolite (SP) were used for the synthesis of hybrid chitosan-clay thin films and porous aerogel microspheres. At a first glance, a decrease in the viscosity of the three gel-forming solutions was noticed as a result of breaking the mutual polymeric chains interaction by the clay microstructure. Upon casting, chitosan-clay films displayed enhanced hydrophilicity in the order CSclay microstructure, an improvement in the mechanical properties of the chitosan-clay films has been substantiated with CS-SP reaching the highest value at 5% clay loading. While clay addition provides a way to resist the shrinkage occurring for native chitosan, the enhanced hydrophilicity associated to the water content affects the efficacy of the CO2 super-critical drying as the most hydrophilic CS-SP microspheres face the highest shrinkage, resulting in a lowest specific surface area compared to CS-HNT and CS-MMT. Chitosan-clay exhibits enhanced thermal properties with the degradation delayed in the order CSclay compared to native chitosan, evidencing the beneficial protective effect of the clay particulates for the biopolymer. However, under hydrothermal treatment, the presence of clay was found to be detrimental to the material stability as a significant shrinkage occurs in hybrid CS-clay microspheres, which is attributed again to their increased hydrophilicity compared to the native polymeric microspheres. In this framework, a peculiar behavior was observed for CS-MMT, with the microspheres standing both against contraction during CO2 gel drying and under hydrothermal conditions. The knowledge gained from this rational design will constitute a guideline toward the preparation of ultra-stable, practically-optimized food

  5. Carbonate cementation as related to the diagenesis of clay in a mixed siliciclastic-carbonate system: Examples from the Centerfield biostrome, east central Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    Burns, C.D. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-03-01

    The Middle Devonian Mahantango Formation consists of siliciclastic and mixed carbonate-siliciclastic sediment packages that pulse in and out of the stratigraphy. The formation crops out in several places throughout the folded rocks of eastern Pennsylvania and Maryland. The Centerfield Member is one of the mixed siliciclastic-carbonate packages in the Mahantango Fm. This member crops out in east central Pennsylvania. The Centerfield Mbr. has been interpreted as a series of biostromes and contain abundant rugosan corals, crinoids, bryozoans, and brachiopods. The biostromes have undergone a complex diagenetic history. Illite, smectite, chlorite and muscovite have been found with the use of powder x-ray diffraction and petrographic analysis. The smectite and some of the illite are depositional clays, while, the remaining illite, chlorite and muscovite represent recrystallization of the depositional clays. There are six phases of cement in the biostrome. The paragenetic sequence of the cements is as follows: non-ferroan low magnesian calcite (LMC), intermediate ferroan LMC, ferroan LMC, non-ferroan dolomite, ferroan baroque dolomite, and quartz cement in the form of chert and blocky cement. Staining shows that the iron content of the cement changes within individual crystals and between cement phases. Preliminary data suggest that the cements may be directly related to the steady release of ions during the diagenesis of the surrounding clays in the shale.

  6. Water Treatment Systems for Long Spaceflights

    Science.gov (United States)

    FLynn, Michael T.

    2012-01-01

    Space exploration will require new life support systems to support the crew on journeys lasting from a few days to several weeks, or longer. These systems should also be designed to reduce the mass required to keep humans alive in space. Water accounts for about 80 percent of the daily mass intake required to keep a person alive. As a result, recycling water offers a high return on investment for space life support. Water recycling can also increase mission safety by providing an emergency supply of drinking water, where another supply is exhausted or contaminated. These technologies also increase safety by providing a lightweight backup to stored supplies, and they allow astronauts to meet daily drinking water requirements by recycling the water contained in their own urine. They also convert urine into concentrated brine that is biologically stable and nonthreatening, and can be safely stored onboard. This approach eliminates the need to have a dedicated vent to dump urine overboard. These needs are met by a system that provides a contaminant treatment pouch, referred to as a urine cell or contaminant cell, that converts urine or another liquid containing contaminants into a fortified drink, engineered to meet human hydration, electrolyte, and caloric requirements, using a variant of forward osmosis (FO) to draw water from a urine container into the concentrated fortified drink as part of a recycling stage. An activated carbon pretreatment removes most organic molecules. Salinity of the initial liquid mix (urine plus other) is synergistically used to enhance the precipitation of organic molecules so that activated carbon can remove most of the organics. A functional osmotic bag is then used to remove inorganic contaminants. If a contaminant is processed for which the saline content is different than optimal for precipitating organic molecules, the saline content of the liquid should be adjusted toward the optimal value for that contaminant. A first urine

  7. Hydraulic characterization of the boom clay formation from the HADES underground laboratory in Mol: evolution and assessment of the piezometric techniques

    International Nuclear Information System (INIS)

    The network of piezometers installed in the Boom clay formation from the HADES Underground laboratory (-223 m) at Mol is an invaluable tool for the measurement and physical understanding of the groundwater flow towards a non closes deep repository system in an argillaceous formation. The hydraulic testing, test interpretation and groundwater sampling methodologies in a plastic clay (19 - 26 % H2O) at medium depth are presented. The results obtained from in situ tests (metric to local scale, 1 to 30 m) and from laboratory experiments on vertical and horizontal clay plugs (centimetric scale, 3 - 7 cm) have put into evidence the anisotropy of the Boom clay. The horizontal hydraulic conductivity is approximately 2.4 times higher than the vertical one. Laboratory and in situ results are discussed. Their comparison gives coherent hydraulic and transport parameters supporting the model used to describe quantitatively the migration of radionuclides through the clay. Meanwhile, concerning the hydraulic conductivity, a large discrepancy still subsists with the regional model (kilometric scale, 40 km x 80 km) which is presently being revisited (i.a. boundary conditions and refinement of the mesh, from 5 to 0.5 km) and with the regional observations often too scarce (water level measurements in the sandy aquifers surrounding the Boom clay formation). (authors). 8 refs., 2 figs., 1 tab

  8. LIGHTWEIGHT GREEN ROOF WATER RETENTION SYSTEM

    Science.gov (United States)

    During Phase I, we have forged numerous necessary partnerships, which will allow us to begin our implementation tests. Working with the Philadelphia Water Department (PWD) and Drexel Smart House (DSH) we have 3 to 4 prime test sites for our system. We plan to execute our insta...

  9. Sustainable Energy, Water and Environmental Systems

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg; Duic, Neven

    2014-01-01

    This issue presents research results from the 8th Conference on Sustainable Development of Energy, Water and Environment Systems – SDEWES - held in Dubrovnik, Croatia in 2013. Topics covered here include the energy situation in the Middle East with a focus in Cyprus and Israel, energy planning...

  10. Clays and Clay Minerals and their environmental application in Food Technology

    Science.gov (United States)

    del Hoyo Martínez, Carmen; Cuéllar Antequera, Jorge; Sánchez Escribano, Vicente; Solange Lozano García, Marina; Cutillas Díez, Raul

    2013-04-01

    The clay materials have led to numerous applications in the field of public health (del Hoyo, 2007; Volzone, 2007) having been demonstrated its effectiveness as adsorbents of all contaminants. Some biodegradable materials are used for for adsorption of chemical contaminants: lignins (Valderrabano et al., 2008) and also clays and clay minerals, whose colloidal properties, ease of generating structural changes, abundance in nature, and low cost make them very suitable for this kind of applications. Among the strategies used at present to preserve the quality of the water and this way to diminish the environmental risk that supposes the chemical pollution, stands out the use of adsorbents of under cost, already they are natural or modified, to immobilize these compounds and to avoid the pollution of the water with the consequent reduction of environmental and economic costs Thanks to the development of the science and the technology of the nourishment in the last 50 years, there have revealed itself several new substances that can fulfill beneficial functions in the food, and these substances, named food additives, are today within reach of all. The food additives recover a very important role in the complex nourishing supply. The additives fulfill several useful functions in the food, which often we give for sat. Nevertheless the widespread use of food additives in the food production also influences the public health. The food industries, which are very important for the economy, spill residues proved from its activity that they have to be controlled to evaluate the environmental impact and to offer the necessary information about the quantitative evaluation of the chemical risk of the use of food additives for the public health. We have studied the adsorption of several contaminants by natural or modified clays, searching their interaction mechanisms and the possible recycling of these materials for environmental purposes and prevention of the health. References

  11. A Water Recovery System Evolved for Exploration

    Science.gov (United States)

    ORourke, Mary Jane E.; Perry, Jay L.; Carter, Donald L.

    2006-01-01

    A new water recovery system designed towards fulfillment of NASA's Vision for Space Exploration is presented. This water recovery system is an evolution of the current state-of-the-art system. Through novel integration of proven technologies for air and water purification, this system promises to elevate existing technology to higher levels of optimization. The novel aspect of the system is twofold: Volatile organic contaminants will be removed from the cabin air via catalytic oxidation in the vapor phase, prior to their absorption into the aqueous phase, and vapor compression distillation technology will be used to process the condensate and hygiene waste streams in addition to the urine waste stream. Oxidation kinetics dictate that removal of volatile organic contaminants from the vapor phase is more efficient. Treatment of the various waste streams by VCD will reduce the load on the expendable ion exchange and adsorption media which follow, and on the aqueous-phase volatile removal assembly further downstream. Incorporating these advantages will reduce the weight, volume, and power requirements of the system, as well as resupply.

  12. Constitutive model for overconsolidated clays

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the relationships between the Hvorslev envelope,the current yield sur-face and the reference yield surface,a new constitutive model for overconsolidated clays is proposed. It adopts the unified hardening parameter,to which the potential failure stress ratio and the characteristic state stress ratio are introduced. The model can describe many characteristics of overconsolidated clays,including stress-strain relationships,strain hardening and softening,stress dilatancy,and stress path dependency. Compared with the Cam-clay model,the model only re-quires one additional soil parameter which is the slope of the Hvorslev envelope. Comparisons with data from triaxial drained compression tests for Fujinomori clay show that the proposed model can rationally describe overconsolidated properties. In addition,the model is also used to predict the stress-strain relationship in the isotropic consolidation condition and the stress paths in the undrained triaxial compression tests.

  13. Constitutive model for overconsolidated clays

    Institute of Scientific and Technical Information of China (English)

    YAO YangPing; HOU Wei; ZHOU AnNan

    2008-01-01

    Based on the relationships between the Hvorslev envelope, the current yield surface and the reference yield surface, a new constitutive model for overconsolidated clays is proposed. It adopts the unified hardening parameter, to which the potential failure stress ratio and the characteristic state stress ratio are introduced. The model can describe many characteristics of overconsolidated clays, including stress-strain relationships, strain hardening and softening, stress dilatancy, and stress path dependency. Compared with the Cam-clay model, the model only requires one additional soil parameter which is the slope of the Hvorslev envelope. Comparisons with data from triaxial drained compression tests for Fujinomori clay show that the proposed model can rationally describe overconsolidated properties. In addition, the model is also used to predict the stress-strain relationship in the isotropic consolidation condition and the stress paths in the undrained triaxial compression tests.

  14. Towards an understanding of the role of clay minerals in crude oil formation, migration and accumulation

    Science.gov (United States)

    Wu, Lin Mei; Zhou, Chun Hui; Keeling, John; Tong, Dong Shen; Yu, Wei Hua

    2012-12-01

    This article reviews progress in the understanding of the role of clay minerals in crude oil formation, migration and accumulation. Clay minerals are involved in the formation of kerogen, catalytic cracking of kerogen into petroleum hydrocarbon, the migration of crude oil, and the continued change to hydrocarbon composition in underground petroleum reservoirs. In kerogen formation, clay minerals act as catalysts and sorbents to immobilize organic matter through ligand exchange, hydrophobic interactions and cation bridges by the mechanisms of Maillard reactions, polyphenol theory, selective preservation and sorptive protection. Clay minerals also serve as catalysts in acid-catalyzed cracking of kerogen into petroleum hydrocarbon through Lewis and Brønsted acid sites on the clay surface. The amount and type of clay mineral affect the composition of the petroleum. Brønsted acidity of clay minerals is affected by the presence and state of interlayer water, and displacement of this water is a probable driver in crude oil migration from source rocks. During crude oil migration and accumulation in reservoirs, the composition of petroleum is continually modified by interaction with clay minerals. The clays continue to function as sorbents and catalysts even while they are being transformed by diagenetic processes. The detail of chemical interactions and reaction mechanisms between clay minerals and crude oil formation remains to be fully explained but promises to provide insights with broader application, including catalytic conversion of biomass as a source of sustainable energy into the future.

  15. Non disturbing characterization and quantification of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electro-spray and atmospheric pressure chemical ionization modes

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The Callovo-Oxfordian formation (COx) rock may contain up to 1% w/w of organic Carbon. Most of the Organic Matter (OM) is attached to the mineral particles whereas a small portion is present as Dissolved Organic Matter (DOM) in the pore water. In environmental studies, Natural Organic Matter (NOM) plays a key role on the bioavailability and the toxicity of metallic compounds. It is necessary to know the structure of any organic substance in order to assess which chemical and biological reactions occur under environmentally relevant conditions. The 150 Myears solid-bound organic matter of the COx (kerogen) has been already investigated in several studies and originates from a mixture of marine and terrestrial sources. In addition to this, the CCl4 soluble organic fraction (bitumen) has been already characterized by liquid and gas chromatography coupled to mass spectrometry. It allows proportion and distribution of biological markers to be determined as polar compounds with aromatic and saturated hydrocarbons. DOM was extracted from a crushed clay rock of the COx formation with a high rock/water ratio of about 1500 g/L. Part of the OM from the COx is known to be sensitive to air oxidation which can significantly modify the nature of the bitumen by an overall shift towards lower molecular weight compounds. Therefore, the characteristics of the DOM must be determined in in-situ like conditions if one wants to assess the mobility of DOM in the clay pore space and to evaluate the mobility of heavy metals/ radionuclides. Due to their high binding capacity with metal ions and their colloidal sizes in natural waters, these macromolecules, through complexation reactions, might either enhance the mobility of trace elements, or reduce their migration rates by sorption processes in relation with their size and that of the porous medium. Consequently, the characterization of DOM in anoxic pore water samples from the COx

  16. Boron Enrichment in Martian Clay

    OpenAIRE

    James D Stephenson; Lydia J Hallis; Kazuhide Nagashima; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest minera...

  17. Wave liquefaction in soils with clay content

    DEFF Research Database (Denmark)

    Kirca, Özgür; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    The paper presents the results of an experimental study of the influence of clay content (in silt-clay and sand-clay mixtures) on liquefaction beneath progressive waves. The experiments showed that the influence of clay content is very significant. Susceptibility of silt to liquefaction is increa...

  18. What makes a natural clay antibacterial?

    Science.gov (United States)

    Williams, Lynda B.; Metge, David W.; Eberl, Dennis D.; Harvey, Ronald W.; Turner, Amanda G.; Prapaipong, Panjai; Port-Peterson, Amisha T.

    2011-01-01

    Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial clays contain nanoscale (2+ solubility.

  19. Water delivery in the Early Solar System

    CERN Document Server

    Dvorak, Rudolf; Süli, Áron; Sándor, Zsolt; Galiazzo, Mattia; Pilat-Lohinger, Elke

    2015-01-01

    As part of the national scientific network 'Pathways to Habitable Worlds' the delivery of water onto terrestrial planets is a key question since water is essential for the development of life as we know it. After summarizing the state of the art we show some first results of the transport of water in the early Solar System for scattered main belt objects. Hereby we investigate the questions whether planetesimals and planetesimal fragments which have gained considerable inclination due to the strong dynamical interactions in the main belt region around 2 AU can be efficient water transporting vessels. The Hungaria asteroid group is the best example that such scenarios are realistic. Assuming that the gas giants and the terrestrial planets are already formed, we monitor the collisions of scattered small bodies containing water (in the order of a few percent) with the terrestrial planets. Thus we are able to give a first estimate concerning the respective contribution of such bodies to the actual water content i...

  20. Experimental study on inclined double solar water distillation system

    OpenAIRE

    Irani, Foad

    2014-01-01

    ABSTRACT: The aim of this project is to design and test the double inclined solar water distillation system and compare it with a single inclined solar water distillation system under the climate conditions of North Cyprus. In an inclined solar water distillation system, the feeding water falls down on the bare plate through the distribution pipe. The double inclined solar water distillation system has two sections. In the lower section the feeding water falls down on the bare plate, through ...

  1. Developing Sustainable Spacecraft Water Management Systems

    Science.gov (United States)

    Thomas, Evan A.; Klaus, David M.

    2009-01-01

    It is well recognized that water handling systems used in a spacecraft are prone to failure caused by biofouling and mineral scaling, which can clog mechanical systems and degrade the performance of capillary-based technologies. Long duration spaceflight applications, such as extended stays at a Lunar Outpost or during a Mars transit mission, will increasingly benefit from hardware that is generally more robust and operationally sustainable overtime. This paper presents potential design and testing considerations for improving the reliability of water handling technologies for exploration spacecraft. Our application of interest is to devise a spacecraft wastewater management system wherein fouling can be accommodated by design attributes of the management hardware, rather than implementing some means of preventing its occurrence.

  2. Clay Minerals Deposit of Halakabad (Sabzevar- Iran)

    OpenAIRE

    Seyed Mohammad Hashemi

    2012-01-01

    Clay minerals are expanded in south of Sabzevar. They are identified with light color in the filed. The XRD and XRF chemical and mineralogical studies on the Clay minerals indicated that their main clay minerals are Kaolinite, Illite and Dickite. Pyrophyllite is minor clay mineral. Quartz and Sanidine non clay minerals are present with clay minerals .Ratio of Al2O3 is about 40 per cent, it is very good for industrial minerals .Volcanic rocks are origin clay minerals .Their composition are bas...

  3. Acid mine water aeration and treatment system

    Science.gov (United States)

    Ackman, Terry E.; Place, John M.

    1987-01-01

    An in-line system is provided for treating acid mine drainage which basically comprises the combination of a jet pump (or pumps) and a static mixer. The jet pump entrains air into the acid waste water using a Venturi effect so as to provide aeration of the waste water while further aeration is provided by the helical vanes of the static mixer. A neutralizing agent is injected into the suction chamber of the jet pump and the static mixer is formed by plural sections offset by 90 degrees.

  4. A Benchmarking System for Domestic Water Use

    Directory of Open Access Journals (Sweden)

    Dexter V. L. Hunt

    2014-05-01

    Full Text Available The national demand for water in the UK is predicted to increase, exacerbated by a growing UK population, and home-grown demands for energy and food. When set against the context of overstretched existing supply sources vulnerable to droughts, particularly in increasingly dense city centres, the delicate balance of matching minimal demands with resource secure supplies becomes critical. When making changes to "internal" demands the role of technological efficiency and user behaviour cannot be ignored, yet existing benchmarking systems traditionally do not consider the latter. This paper investigates the practicalities of adopting a domestic benchmarking system (using a band rating that allows individual users to assess their current water use performance against what is possible. The benchmarking system allows users to achieve higher benchmarks through any approach that reduces water consumption. The sensitivity of water use benchmarks are investigated by making changes to user behaviour and technology. The impact of adopting localised supplies (i.e., Rainwater harvesting—RWH and Grey water—GW and including "external" gardening demands are investigated. This includes the impacts (in isolation and combination of the following: occupancy rates (1 to 4; roof size (12.5 m2 to 100 m2; garden size (25 m2 to 100 m2 and geographical location (North West, Midlands and South East, UK with yearly temporal effects (i.e., rainfall and temperature. Lessons learnt from analysis of the proposed benchmarking system are made throughout this paper, in particular its compatibility with the existing Code for Sustainable Homes (CSH accreditation system. Conclusions are subsequently drawn for the robustness of the proposed system.

  5. Reduction in Rebound of Concrete Piles Driven into Clays by Coating Pile Surface with Titanium Dioxide Nanoparticles

    OpenAIRE

    Amalia, Nadya; Asri, Asifa; Rokhmat, Mamat; Sutisna; Abdullah, Mikrajuddin

    2015-01-01

    Using a model for concrete piles driven into clays, we compared penetration depths between uncoated piles and piles coated with titanium dioxide (TiO2) nanoparticles. The behavior of surfaces coated with TiO2 changes to superhydrophilic, enabling water molecules to penetrate inside the clay pores. The attraction suppresses or reduces the compression of water inside the clay pores. The absence of bulk pressure from water causes the pile not to bounce (backward movement after striking). Contrar...

  6. Adsorption of chloroacetanilide herbicides on soil and its components Ⅲ. Influence of clay acidity, humic acid coating and herbicide structure on acetanilide herbicide adsorption on homoionic clays

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca2 + -, Mg2 + -. Al3 + -and Fe3 + -saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, Kf decreased in the order of metolachlor > acetolachlor > alachlor > propachlor on the same clay. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg2+ < Ca2+ < Al3+ ≤ Fe3+ which coincided with the iucreasing aciditv of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions.

  7. Army Energy and Water Reporting System Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Deprez, Peggy C.; Giardinelli, Michael J.; Burke, John S.; Connell, Linda M.

    2011-09-01

    There are many areas of desired improvement for the Army Energy and Water Reporting System. The purpose of system is to serve as a data repository for collecting information from energy managers, which is then compiled into an annual energy report. This document summarizes reported shortcomings of the system and provides several alternative approaches for improving application usability and adding functionality. The U.S. Army has been using Army Energy and Water Reporting System (AEWRS) for many years to collect and compile energy data from installations for facilitating compliance with Federal and Department of Defense energy management program reporting requirements. In this analysis, staff from Pacific Northwest National Laboratory found that substantial opportunities exist to expand AEWRS functions to better assist the Army to effectively manage energy programs. Army leadership must decide if it wants to invest in expanding AEWRS capabilities as a web-based, enterprise-wide tool for improving the Army Energy and Water Management Program or simply maintaining a bottom-up reporting tool. This report looks at both improving system functionality from an operational perspective and increasing user-friendliness, but also as a tool for potential improvements to increase program effectiveness. The authors of this report recommend focusing on making the system easier for energy managers to input accurate data as the top priority for improving AEWRS. The next major focus of improvement would be improved reporting. The AEWRS user interface is dated and not user friendly, and a new system is recommended. While there are relatively minor improvements that could be made to the existing system to make it easier to use, significant improvements will be achieved with a user-friendly interface, new architecture, and a design that permits scalability and reliability. An expanded data set would naturally have need of additional requirements gathering and a focus on integrating

  8. Modification of clay-based waste containment materials

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K. [DuPont Central Research and Development, Newark, DE (United States); Whang, J.M. [DuPont Specialty Chemicals, Deepwater, NJ (United States); McDevitt, M.F. [DuPont Central Research and Development, Wilmington, DE (United States)

    1997-12-31

    Bentonite clays are used extensively for waste containment barriers to help impede the flow of water in the subsurface because of their low permeability characteristics. However, they do little to prevent diffusion of contaminants, which is the major transport mechanism at low water flows. A more effective way of minimizing contaminant migration in the subsurface is to modify the bentonite clay with highly sorptive materials. Batch sorption studies were conducted to evaluate the sorptive capabilities of organo-clays and humic- and iron-based materials. These materials proved to be effective sorbents for the organic contaminants 1,2,4-trichlorobenzene, nitrobenzene, and aniline in water, humic acid, and methanol solution media. The sorption capacities were several orders of magnitude greater than that of unmodified bentonite clay. Modeling results indicate that with small amounts of these materials used as additives in clay barriers, contaminant flux through walls could be kept very small for 100 years or more. The cost of such levels of additives can be small compared to overall construction costs.

  9. Fluoride content of clay minerals and argillaceous earth materials

    Science.gov (United States)

    Thomas, J., Jr.; Glass, H.D.; White, W.A.; Trandel, R.M.

    1977-01-01

    A reliable method, utilizing a fluoride ion-selective electrode, is described for the determination of fluoride in clays and shales. Interference by aluminum and iron is minimal. The reproducibility of the method is about ??5% at different levels of fluoride concentration. Data are presented for various clay minerals and for the clays and shales. Fluoride values range from 44 ppm (0.0044%) for nontronite from Colfax, WA, to 51,800 ppm (5.18%) for hectorite from Hector, CA. In general, clays formed under hydrothermal conditions are relatively high in fluoride content, provided the hydrothermal waters are high in fluoride content. Besides hectorite, dickite from Ouray, CO, was found to contain more than 50 times as much fluoride (6700 ppm) as highly crystalline geode kaolinite (125 ppm). The clay stratum immediately overlying a fluorite mineralized zone in southern Illinois was found to have a higher fluoride content than the same stratum in a nonmineralized zone approximately 1 mile away. Nonmarine shales in contact with Australian coals were found to be lower in fluoride content than were marine shales in contact with Illinois coals. It is believed that, in certain instances, peak shifts on DTA curves of similar clay minerals are the result of significant differences in their fluoride content. ?? 1977.

  10. Adsorption of diethyl phthalate ester to clay minerals.

    Science.gov (United States)

    Wu, Yanhua; Si, Youbin; Zhou, Dongmei; Gao, Juan

    2015-01-01

    Phthalate esters are a group of plasticizers, which have been widely detected in China's agricultural and industrial soils. In this study, batch adsorption experiments were conducted to investigate the environmental effects on the adsorption of diethyl phthalate ester (DEP) to clay minerals. The results showed that DEP adsorption isotherms were well fitted with the Freundlich model; the interlayer spacing of K(+) saturated montmorillonite (K-mont) was the most important adsorption area for DEP, and di-n-butyl ester (DnBP) was limited to intercalate into the interlayer of K-mont due to the bigger molecular size; there was no significant effect of pH and ionic strength on DEP adsorption to K-mont/Ca-mont, but to Na-mont clay. The adsorption to kaolinite was very limited. Data of X-ray diffraction and FTIR spectra further proved that DEP molecules could intercalate into K-/Ca-mont interlayer, and might interact with clay through H-bonding between carbonyl groups and clay adsorbed water. Coated humic acid on clay surface would enhance DEP adsorption at low concentration, but not at high concentration (eg. Ce>0.26 mM). The calculated adsorption enthalpy (ΔHobs) and adsorption isotherms at varied temperatures showed that DEP could be adsorbed easier as more adsorbed. This study implied that clay type, compound structure, exchangeable cation, soil organic matter and temperature played important roles in phthalate ester's transport in soil.

  11. Summary and conclusions of the faults-in-clay project

    International Nuclear Information System (INIS)

    This report summarises a research project carried out by the British Geological Survey, in cooperation with ISMES of Italy, into the geophysical detection of faults in clay formations and the determination of the hydrogeological effects of such faults on the groundwater flow regime. Following evaluation of potential research sites, an extensive programme of investigations was conducted at Down Ampney, Gloucester, where the Oxford Clay formation is underlain by the aquifers of the Great Oolite Limestone group. A previously unknown fault of 50 m throw was identified and delineated by electrical resistivity profiling; the subsequent development of a technique utilising measurements of total resistance improved the resolution of the fault 'location' to an accuracy of better than one metre. Marked anisotropy of the clay resistivities complicates conventional geophysical interpretation, but gives rise to a characteristic anomaly across the steeply inclined strata in the fault zone. After exploratory core drilling, an array of 13 boreholes was designed and completed for cross-hole seismic tomography and hydrogeological measurement and testing. The groundwater heads in the clays were found to be in disequilibrium with those in the aquifers, as a result of water supply abstraction. The indication is that the hydraulic conductivity of the fault zone is higher than that of the surrounding clay by between one and two orders of magnitude. Methodologies for the general investigation of faults in clay are discussed. (Author)

  12. Facts and features of radionuclide migration in Boom Clay

    International Nuclear Information System (INIS)

    The evolution which took place during ten years of research on the behaviour of radionuclides in Boom Clay is described. Initially, the Boom Clay was regarded as a chemically inert exchanger and the radiochemical research aimed at determining the distribution of cations between the clay and some liquid phases. The observation that Boom Clay deteriorates in contact with air and loses important intrinsic properties formed a major breakthrough in the research and led to a careful examination of the real in-situ conditions. Efforts devoted to the understanding of the chemical factors pertaining to the pH, the redox potential, the extent of the buffering capacity of FeS2 and CaCO3 in equilibrium with the interstitial aqueous phase are reviewed. Also emerging from the overall picture was the role of the organic material present in the Boom Clay. In contrast to the water percolating fractured formations which may not be in equilibrium with the rock, the interstitial aqueous phase is completely in equilibrium with Boom Clay mainly because of its low permeability and the large excesses of buffering components. As the retention mechanisms are better understood, a more coherent picture is obtained from distribution and diffusion experiments and the effects of consolidation are being investigated in detail. 23 refs.; 4 figs.; 3 tabs

  13. Uranium release from boom clay in bicarbonate media

    International Nuclear Information System (INIS)

    The release of natural uranium from Boom Clay was studied to better understand the mechanisms governing the solid-liquid partitioning of uranium. Batch leaching experiments suggested that the portion of natural uranium released from clay is associated with colloids at a low bicarbonate concentration prevailing in Boom Clay. At increased bicarbonate concentrations, uranium was present predominantly as dissolved species indicating a formation of uranium carbonate complexes. The in situ aqueous uranium concentration, i.e., the concentration in the pore waters collected by piezometers was found to be 2 to 3 orders of magnitudes lower than the one measured by the batch techniques. These results illustrated that the batch techniques may cause a remobilization of uranium containing colloids from clay surfaces into solution when clay is suspended, agitated, and mechanically perturbed. These colloids are attributed to artefacts and are not considered to exist in situ because of the high compaction of Boom Clay. Due to the presence of colloids, a laboratory derived solid-liquid partitioning coefficient is not equivalent to and cannot simply be converted to the distribution coefficient Kd currently used in performance assessment calculations. (orig.)

  14. Evaluate the action of polymeric additives in protect and recover water and bentonite clay based drilling fluids contaminated by degradation agents; Analise da acao de aditivos polimericos na protecao e recuperacao de fluidos de perfuracao base agua e bentonita contaminados por sais

    Energy Technology Data Exchange (ETDEWEB)

    Campos, L.F.A.; Ferreira, H.S.; Amorim, L.V.; Franca, K.B.; Ferreira, H.C. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    The aim of this paper is study influences of electrolytes and cellulose polymers on rheological and water loss properties of dispersions of bentonite compositions. Evaluate the action of degradation additives CaSO{sub 4}, MgCl{sub 2} and CaCl{sub 2} and polymeric additives to protect and recover water and clay based. The results show a negative effect of degradation additives the rheological and water loss properties of drilling fluids. The cellulose polymers can be successfully applied to protect and recover of the rheological properties and water loss of the dispersions contaminated. (author)

  15. Diagnosing Causes of Water Scarcity in Complex Water Resources Systems and Identifying Risk Management Actions

    OpenAIRE

    Martín Carrasco, Francisco Javier; Garrote de Marcos, Luis; Ana IGLESIAS; Mediero Orduña, Luis

    2013-01-01

    From the water management perspective, water scarcity is an unacceptable risk of facing water shortages to serve water demands in the near future. Water scarcity may be temporary and related to drought conditions or other accidental situation, or may be permanent and due to deeper causes such as excessive demand growth, lack of infrastructure for water storage or transport, or constraints in water management. Diagnosing the causes of water scarcity in complex water resources systems is a prec...

  16. Effect of clays on the fire-retardant properties of a polyethylenic copolymer containing intumescent formulation

    Directory of Open Access Journals (Sweden)

    Simone P S Ribeiro et al

    2008-01-01

    Full Text Available Organophilic clay particles were added to a standard intumescent formulation and, since the role of clay expansion or intercalation is still a matter of much controversy, several clays with varying degrees of interlayer distances were evaluated. The composites were obtained by blending the nanostructured clay and the intumescent system with a polyethylenic copolymer. The flame-retardant properties of the materials were evaluated by the limiting oxygen index (LOI, the UL-94 rating and thermogravimetric analysis (TGA. The results showed that the addition of highly expanded clays to the ammonium polyphosphate and pentaerythritol formulation does not significantly increase the flame retardancy of the mixture, when measured by the LOI and UL-94. However, when clays with smaller basal distances were added to the intumescent formulation, a synergistic effect was observed. In contrast, the simple addition of clays to the copolymer, without the intumescent formulation, did not increase the fire retardance of the materials.

  17. Fixation of Selenium by Clay Minerals and Iron Oxides

    DEFF Research Database (Denmark)

    Hamdy, A. A.; Nielsen, Gunnar Gissel

    1977-01-01

    In studying Se fixation, soil components capable of retaining Se were investigated. The importance of Fe hydrous oxides in the fixation of Se was established. The clay minerals common to soils, such as kaolinite, montmorillonite and vermiculite, all exhibited Se fixation, but greater fixation...... occurred with the 1:1 than the 2:1 clay type. Experiments with finely ground minerals showed that the pH of the systems greatly influenced the rate of fixation, reaching a maximum between pH 3 and 5 and decreasing rapidly as the pH increased. With the Fe2O3 system fixed Se was slightly reduced as the p......H was increased to over 8. The extractability of Se from the clay minerals indicated that 1:1 clay type minerals fix selenite more indissolubly than 2:1 clays and that selenite was adsorbed on the clays mainly by a surface exchange reaction. The major part of the selenite added to the Fe2O3 system was found...

  18. Enrichment of trace elements in the clay size fraction of mining soils.

    Science.gov (United States)

    Gomes, Patrícia; Valente, Teresa; Braga, M Amália Sequeira; Grande, J A; de la Torre, M L

    2016-04-01

    Reactive waste dumps with sulfide minerals promote acid mine drainage (AMD), which results in water and soil contamination by metals and metalloids. In these systems, contamination is regulated by many factors, such as mineralogical composition of soil and the presence of sorption sites on specific mineral phases. So, the present study dedicates itself to understanding the distribution of trace elements in different size fractions (clay size fraction. Hence, the higher degree of contamination by toxic elements, especially arsenic in Penedono as well as the role of clay minerals, jarosite, and goethite in retaining trace elements has management implications. Such information must be carefully thought in the rehabilitation projects to be planned for both waste dumps. PMID:25712883

  19. Enrichment of trace elements in the clay size fraction of mining soils.

    Science.gov (United States)

    Gomes, Patrícia; Valente, Teresa; Braga, M Amália Sequeira; Grande, J A; de la Torre, M L

    2016-04-01

    Reactive waste dumps with sulfide minerals promote acid mine drainage (AMD), which results in water and soil contamination by metals and metalloids. In these systems, contamination is regulated by many factors, such as mineralogical composition of soil and the presence of sorption sites on specific mineral phases. So, the present study dedicates itself to understanding the distribution of trace elements in different size fractions (clay size fraction. Hence, the higher degree of contamination by toxic elements, especially arsenic in Penedono as well as the role of clay minerals, jarosite, and goethite in retaining trace elements has management implications. Such information must be carefully thought in the rehabilitation projects to be planned for both waste dumps.

  20. Preferential transport of water and 131Iodide in a clay loam assessed with TDR-techniques and boundary-layer flow theory

    Directory of Open Access Journals (Sweden)

    A. Mdaghri Alaoui

    1997-01-01

    Full Text Available Rapid soil moisture variations were measured with TDR equipment at five depths ranging from 0.1 to 0.9 m during five consecutive infiltration experiments under ponding. Each time, 27 mm of water were applied. The water of the second experiment was spiked with 200 mbq of K131I-tracer. Its activity was recorded as functions of depth and time with Geiger-Müller probes in 12 vertically installed access tubes. The soil moisture variations were classified as showing (i no reaction, (ii monotonous increase, and (iii rapid increase followed by a gradual decrease. Reaction type (iii was investigated further according to the boundary-layer flow theory and diagnosed as preferential flow. Rapid variations of 131I-activities occurred at all depths showing soil moisture reaction type (iii. However, some of the reaction types (i and (ii also included rapid variations of the activities. The approach based on boundary-laver flow theory allows fluxes to be estimated from soil moisture variations. Seven estimated total volumes of rapid flow ranged from 0.15 to 1.1 of the applied volume of water, and in only one case was the total volume badly overestimated by a factor of almost 3. The approach is worth further exploration.

  1. Iron-rich clay minerals on Mars - Potential sources or sinks for hydrogen and indicators of hydrogen loss over time

    Science.gov (United States)

    Burt, D. M.

    1989-01-01

    Although direct evidence is lacking, indirect evidence suggests that iron-rich clay minerals or poorly-ordered chemical equivalents are widespread on the Martian surface. Such clays can act as sources or sinks for hydrogen ('hydrogen sponges'). Ferrous clays can lose hydrogen and ferric clays gain it by the coupled substitution Fe(3+)O(Fe(2+)OH)-1, equivalent to minus atomic H. This 'oxy-clay' substitution involves only proton and electron migration through the crystal structure, and therefore occurs nondestructively and reversibly, at relatively low temperatures. The reversible, low-temperature nature of this reaction contrasts with the irreversible nature of destructive dehydroxylation (H2O loss) suffered by clays heated to high temperatures. In theory, metastable ferric oxy-clays formed by dehydrogenation of ferrous clays over geologic time could, if exposed to water vapor, extract the hydrogen from it, releasing oxygen.

  2. Clay minerals and sedimentary basin history

    OpenAIRE

    Merriman, Richard J.

    2005-01-01

    Clay minerals in the mud and soil that coat the Earth's surface are part of a clay cycle that breaks down and creates rock in the crust. Clays generated by surface weathering and shallow diagenetic processes are transformed into mature clay mineral assemblages in the mudrocks found in sedimentary basins. During metamorphism, the release of alkali elements and boron from clay minerals generates magmas that are subsequently weathered and recycled, representing the magma-to-mud pathway of the cl...

  3. Homogeneity vs. Heterogeneity of Porosity in Boom Clay

    International Nuclear Information System (INIS)

    Microstructural investigations on Boom Clay at nano- to micrometer scale, using BIB-SEM methods, result in porosity characterization for different mineral phases from direct observations on high resolution SE2-images of representative elementary areas (REAs). High quality, polished surfaces of cross-sections of ∼ 1 mm2 size were produced on three different samples from the Mol-Dessel research site (Belgium). More than 33,000 pores were detected, manually segmented and analyzed with regard to their size, shape and orientation. Two main pore classes were defined: Small pores (< 500 nm (ED)) within the clay matrices of samples and =big' pores (> 500 nm (ED)) at the interfaces between clay and non-clay mineral (NCM) grains. Samples investigated show similar porosities regarding the first pore-class, but differences occur at the interfaces between clay matrix and NCM grains. These differences were interpreted to be due to differences in quantitative mineralogy (amount of non-clay mineral grains) and grain-size distributions between samples investigated. Visible porosities were measured as 15 to 17 % for samples investigated. Pore-size distributions of pores in clay are similar for all samples, showing log-normal distributions with peaks around 60 nm (ED) and more than 95 % of the pores being smaller than 500 nm (ED). Fitting pore-size distributions using power-laws with exponents between 1.56 and 1.7, assuming self-similarity of the pore space, thus pores smaller than the pore detection resolution following the same power-laws and using these power-laws for extrapolation of pore-size distributions below the limit of pore detection resolution, results in total estimated porosities between 20 and 30 %. These results are in good agreement with data known from Mercury Porosimetry investigations (35-40 % porosity) and water content porosity measurements (∼ 36 %) performed on Boom Clay. (authors)

  4. Use of swelling clays to reduce permeability and its potential application to nuclear waste repository sealing

    Science.gov (United States)

    Moore, D. E.; Morrow, C. A.; Byerlee, J. D.

    1982-09-01

    The injection of swelling-clay slurries into joints or faults at a deep-burial nuclear waste disposal site may result in significant permeability reductions for the effective containment of radioactive wastes. In an experiment conducted to illustrate the permeability change accompanying clay swelling, a coarse stone with interconnected pore spaces was injected with a clay-electrolyte slurry, modelling the pressure-grouting of a fractured repository rock. Subsequently, solutions with lower electrolyte concentrations were driven through the clay-filled stone, corresponding to migration of lower salinity ground-waters through the clay-grouted fracture. The initial injection procedure reduced the permeability of the stone from 1-10 darcies to 700 nanodarcies; the changes in solution composition decreased permeability by more than 2 additional orders of magnitude to 3 nanodarcies. For application at a nuclear waste repository, the electrolyte concentration of the injected clay slurry should be made higher than that of the ground-water in the host rock. Subsequent interaction of the ground-water with the clays would initiate swelling and create the additional, post-injection permeability reductions that may be important in preventing the escape of buried radioactive wastes. The measured permeability of the clay filling is considerably lower than that of cement tested for borehole plugging. Clays also have the advantage over cement and chemical grouts in that they are geologically stable at relatively low temperatures and have a high capacity for radionuclide adsorption.

  5. Soil Water and Temperature System (SWATS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Bond, D

    2005-01-01

    The soil water and temperature system (SWATS) provides vertical profiles of soil temperature, soil-water potential, and soil moisture as a function of depth below the ground surface at hourly intervals. The temperature profiles are measured directly by in situ sensors at the Central Facility and many of the extended facilities of the SGP climate research site. The soil-water potential and soil moisture profiles are derived from measurements of soil temperature rise in response to small inputs of heat. Atmospheric scientists use the data in climate models to determine boundary conditions and to estimate the surface energy flux. The data are also useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil.

  6. Operational water management of Rijnland water system and pilot of ensemble forecasting system for flood control

    Science.gov (United States)

    van der Zwan, Rene

    2013-04-01

    The Rijnland water system is situated in the western part of the Netherlands, and is a low-lying area of which 90% is below sea-level. The area covers 1,100 square kilometres, where 1.3 million people live, work, travel and enjoy leisure. The District Water Control Board of Rijnland is responsible for flood defence, water quantity and quality management. This includes design and maintenance of flood defence structures, control of regulating structures for an adequate water level management, and waste water treatment. For water quantity management Rijnland uses, besides an online monitoring network for collecting water level and precipitation data, a real time control decision support system. This decision support system consists of deterministic hydro-meteorological forecasts with a 24-hr forecast horizon, coupled with a control module that provides optimal operation schedules for the storage basin pumping stations. The uncertainty of the rainfall forecast is not forwarded in the hydrological prediction. At this moment 65% of the pumping capacity of the storage basin pumping stations can be automatically controlled by the decision control system. Within 5 years, after renovation of two other pumping stations, the total capacity of 200 m3/s will be automatically controlled. In critical conditions there is a need of both a longer forecast horizon and a probabilistic forecast. Therefore ensemble precipitation forecasts of the ECMWF are already consulted off-line during dry-spells, and Rijnland is running a pilot operational system providing 10-day water level ensemble forecasts. The use of EPS during dry-spells and the findings of the pilot will be presented. Challenges and next steps towards on-line implementation of ensemble forecasts for risk-based operational management of the Rijnland water system will be discussed. An important element in that discussion is the question: will policy and decision makers, operator and citizens adapt this Anticipatory Water

  7. Biofouling and biocorrosion in industrial water systems.

    Science.gov (United States)

    Coetser, S E; Cloete, T E

    2005-01-01

    Corrosion associated with microorganisms has been recognized for over 50 years and yet the study of microbiologically influenced corrosion (MIC) is relatively new. MIC can occur in diverse environments and is not limited to aqueous corrosion under submerged conditions, but also takes place in humid atmospheres. Biofouling of industrial water systems is the phenomenon whereby surfaces in contact with water are colonized by microorganisms, which are ubiquitous in our environment. However, the economic implications of biofouling in industrial water systems are much greater than many people realize. In a survey conducted by the National Association of Corrosion Engineers of the United States ten years ago, it was found that many corrosion engineer did not accept the role of bacteria in corrosion, and many of then that did, could not recognize and mitigate the problem. Biofouling can be described in terms of its effects on processes and products such as material degradation (bio-corossion), product contamination, mechanical blockages, and impedance of heat transfer. Microorganisms distinguish themselves from other industrial water contaminants by their ability to utilize available nutrient sources, reproduce, and generate intra- and extracellular organic and inorganic substances in water. A sound understanding of the molecular and physiological activities of the microorganisms involved is necessary before strategies for the long term control of biofouling can be format. Traditional water treatment strategies however, have largely failed to address those factors that promote biofouling activities and lead to biocorrosion. Some of the major developments in recent years have been a redefinition of biofilm architecture and the realization that MIC of metals can be best understood as biomineralization.

  8. Piping installation for reactor heavy water system

    International Nuclear Information System (INIS)

    Characteristics and main installation steps for the piping of the reactor heavy water loop system were introduced in this paper. According to the system design, equipment accommodation and spot management, main issues with effect on the quality and schedule of pipeline installation were analyzed. Accordingly, some solutions were put forward, which included: work allocation should be made clear in documents; installation preparative such as design checkup and technology communication should be prepared completely; requirements of system cleaning, test items in every experiment, inspection in work and equipment maintenance should be considered in the system design; perfect documents distribution system and stock plan should be built; technology requirements and quality assurance should be claimed in contracts; quality should be controlled by way of external evidence, inspection in manufactory, exterior quality assurance examination, and test during consignment; series of management procedure should be established in detail. (authors)

  9. Prototype solar heating and hot water systems

    Science.gov (United States)

    1977-01-01

    Alternative approaches to solar heating and hot water system configurations were studied, parametrizing the number and location of the dampers, the number and location of the fans, the interface locations with the furnace, the size and type of subsystems, and operating modes. A two-pass air-heating collector was selected based on efficiency and ease of installation. Also, an energy transport module was designed to compactly contain all the mechanical and electrical control components. System performance calculations were carried out over a heating season for the tentative site location at Tunkhnana, Pa. Results illustrate the effect of collector size, storage capacity, and use of a reflector. Factors which affected system performance include site location, insulative quality of the house, and of the system components. A preliminary system performance specification is given.

  10. Hydration of swelling clay and bacteria interaction. An experimental in situ reaction study

    International Nuclear Information System (INIS)

    This study reports on the physical-chemical behaviour of swelling di-octahedral clays (smectites) and their interaction with aqueous solutions and bacteria (Shewanella putrefaciens). Experimental results are presented for compacted clays, hydrated under confined volume conditions, using a new type of reaction-cell (the 'wet-cell' of Warr and Hoffman, 2004) that was designed for in situ X-ray diffraction (XRD) measurement. For comparison, dispersed clay systems were studied using standard batch solutions subjected to varying degrees of agitation. The combination of time-dependent in situ XRD measurements with gravimetric measurements and calculated diffraction patterns using the CALCMIX software (Plancon and Drits, 1999) allowed to successful quantification of the dynamics of water uptake and storage. This analytical procedure combined with published water vapour adsorption data enabled determination of the abundance of structured water layers, developed in the interlayer space, and the amount of water contained in different storage sites (interlayers, surfaces and pore spaces). Qualitative information on surface area and textural organization was also estimated based on calculated changes in the average particle thickness and the organization of water layer structures (ordering). Abiotic smectite hydration experiments, using a range of natural and industrial bentonites (SWy-2, IBECO, MX80, TIXOTON), focused on defining the role of the interlayer cation, variable clay packing densities and the ionic strength of the infiltrating solution. The rate of smectite hydration, as expected, was seen to be highly dependent on the type of interlayer cation (enhanced for Ca as opposed to Na) and the ionic strength of solution (enhanced uptake rates with saline solutions, particularly as they infiltrate Na-smectite). A range of dynamic changes in micro textural state occurred as a function of packing density. These changes explain the differences in hydration behaviour observed

  11. Guidelines for transient analysis in water transmission and distribution systems

    NARCIS (Netherlands)

    Pothof, I.W.M.; Karney, B.W.

    2012-01-01

    All water systems leak, and many supply systems do so considerably, with water losses typically of approximately 20% of the water production. The IWA Water Loss Task Force aims for a significant reduction of annual water losses by drafting documents to assist practitioners and others to prevent, mon

  12. Operational cost minimization in cooling water systems

    Directory of Open Access Journals (Sweden)

    Castro M.M.

    2000-01-01

    Full Text Available In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.

  13. Clays Can Decrease Gaseous Nutrient Losses from Soil-Applied Livestock Manures.

    Science.gov (United States)

    Pratt, Chris; Redding, Matthew; Hill, Jaye; Brown, Grant; Westermann, Maren

    2016-03-01

    Clays could underpin a viable agricultural greenhouse gas (GHG) abatement technology given their affinity for nitrogen and carbon compounds. We provide the first investigation into the efficacy of clays to decrease agricultural nitrogen GHG emissions (i.e., NO and NH). Via laboratory experiments using an automated closed-vessel analysis system, we tested the capacity of two clays (vermiculite and bentonite) to decrease NO and NH emissions and organic carbon losses from livestock manures (beef, pig, poultry, and egg layer) incorporated into an agricultural soil. Clay addition levels varied, with a maximum of 1:1 to manure (dry weight). Cumulative gas emissions were modeled using the biological logistic function, with 15 of 16 treatments successfully fitted ( oxide emissions were significantly lower (×3; < 0.05) at the highest clay addition level compared with no clay addition. When assessing manures individually, we observed generally decreasing trends in NH and NO emissions with increasing clay addition, albeit with widely varying statistical significance between manure types. Most of the treatments also showed strong evidence of increased C retention with increasing clay additions, with up to 10 times more carbon retained in treatments containing clay compared with treatments containing no clay. This preliminary assessment of the efficacy of clays to mitigate agricultural GHG emissions indicates strong promise. PMID:27065411

  14. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (volume 2)

    International Nuclear Information System (INIS)

    This study is composed of two parts: The first part (Volume 1) lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton during thermal dilatation. The second part (volume 2) is devoted to the development and the application of advance constitutive modelling of mechanical behaviour of clays taking into account the extensive tests of Boom clay reported in the first volume. The development concentrated on the improvement of prediction of the volumetric response of clay skeleton: (a) improving the dilatancy prediction at low to high overconsolidation ratios (Section 2). An elasto-plastic constitutive model has been developed to account for this effect (Section 3.2.); (b) modelling of swelling effects (Section 2.5). A preliminary interpretative model for swelling prediction has been developed (Section 2.5). The application part consisted in interpreting the experimental results obtained for Boom clay to calibrate a set of constants (Section 3) for performing numerical analyses (Section 4) for the thermomechanical model already calibrated for Boom clay (Appendix). Interpretation of the tests required an assessment of influence of the strong anisotropy effects revealed by Boom clay on the basis of an interpretative model characterized by a kinematic hardening plasticity and coupled elasticity (section 3)

  15. 21 CFR 884.6170 - Assisted reproduction water and water purification systems.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction water and water purification... Devices § 884.6170 Assisted reproduction water and water purification systems. (a) Identification. Assisted reproduction water purification systems are devices specifically intended to generate high...

  16. Diverless pipeline repair system for deep water

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli, Carlo M. [Eni Gas and Power, Milan (Italy); Fabbri, Sergio; Bachetta, Giuseppe [Saipem/SES, Venice (Italy)

    2009-07-01

    SiRCoS (Sistema Riparazione Condotte Sottomarine) is a diverless pipeline repair system composed of a suite of tools to perform a reliable subsea pipeline repair intervention in deep and ultra deep water which has been on the ground of the long lasting experience of Eni and Saipem in designing, laying and operating deep water pipelines. The key element of SiRCoS is a Connection System comprising two end connectors and a repair spool piece to replace a damaged pipeline section. A Repair Clamp with elastomeric seals is also available for pipe local damages. The Connection System is based on pipe cold forging process, consisting in swaging the pipe inside connectors with suitable profile, by using high pressure seawater. Three swaging operations have to be performed to replace the damaged pipe length. This technology has been developed through extensive theoretical work and laboratory testing, ending in a Type Approval by DNV over pipe sizes ranging from 20 inches to 48 inches OD. A complete SiRCoS system has been realised for the Green Stream pipeline, thoroughly tested in workshop as well as in shallow water and is now ready, in the event of an emergency situation.The key functional requirements for the system are: diverless repair intervention and fully piggability after repair. Eni owns this technology and is now available to other operators under Repair Club arrangement providing stand-by repair services carried out by Saipem Energy Services. The paper gives a description of the main features of the Repair System as well as an insight into the technological developments on pipe cold forging reliability and long term duration evaluation. (author)

  17. Water masers in the Kronian system

    Science.gov (United States)

    Pogrebenko, Sergei V.; Gurvits, Leonid I.; Elitzur, Moshe; Cosmovici, Cristiano B.; Avruch, Ian M.; Pluchino, Salvatore; Montebugnoli, Stelio; Salerno, Emma; Maccaferri, Giuseppe; Mujunen, Ari; Ritakari, Jouko; Molera, Guifre; Wagner, Jan; Uunila, Minttu; Cimo, Giuseppe; Schilliro, Francesco; Bartolini, Marco

    The presence of water has been considered for a long time as a key condition for life in planetary environments. The Cassini mission discovered water vapour in the Kronian system by detecting absorption of UV emission from a background star (Hansen et al. 2006). Prompted by this discovery, we started an observational campaign for search of another manifestation of the water vapour in the Kronian system, its maser emission at the frequency of 22 GHz (1.35 cm wavelength). Observations with the 32 m Medicina radio telescope (INAF-IRA, Italy) started in 2006 using Mk5A data recording and the JIVE-Huygens software correlator. Later on, an on-line spectrometer was used at Medicina. The 14 m Metsähovi radio telescope (TKK-MRO, Finland) joined the observational campaign in 2008 using a locally developed data capture unit and software spectrometer. More than 300 hours of observations were collected in 2006-2008 campaign with the two radio telescopes. The data were analysed at JIVE using the Doppler tracking technique to compensate the observed spectra for the radial Doppler shift for various bodies in the Kronian system (Pogrebenko et al. 2009). Here we report the observational results for Hyperion, Titan, Enceladus and Atlas, and their physical interpretation. Encouraged by these results we started a campaign of follow up observations including other radio telescopes.

  18. Property and performance amelioration of pelagic clay from the East Pacific

    Institute of Scientific and Technical Information of China (English)

    Peiping ZHANG; Shufeng LIU; Xuefa SHI; Huahua LU; Juanjuan LIU; Xiaoguo CHI

    2008-01-01

    To make use of the pelagic clay as polymer filling, the properties of clay sediments from the ocean investigation zone of China in the East Pacific were studied by the SSA, XRF, ICP/MAS, FHR, XRD, SEM, DTA/TG and granularity distributing etc. , and experiments were settled to improve the whiteness and activation of the clay based on these data. Compared with land clay, pelagic clay holds many particular features, such as fine particles and incompact accumulation, worse crystallization and more defects, high activity, complex mineral and chemical components, and low whiteness etc. Processing the purified pelagic clay with acids and zinc, then baked it at different temperatures, the whiteness of clay can be increased from 23.8% to 73.1%, and the optimized conditions is : consistency of vitriol 25%, ratio of clay to water 4:1, reaction time 4h, reaction temperature 90℃, dosage of zinc 2.0 g/L, and baking temperature 700℃. And the SSA of whited clay is increased too. Using the dry milling method to modify the pelagic clay with organic reagents, the optimized technique is KH550, concentration 1.5%, reaction time 20 min. XRD,FTIR and SEM testing indicate that the mechanism of organic activation was mainly surface absorbing and chemical combination secondly.

  19. In situ interaction between different concretes and Opalinus Clay

    Science.gov (United States)

    Jenni, A.; Mäder, U.; Lerouge, C.; Gaboreau, S.; Schwyn, B.

    Interactions between cementitious materials and claystone are driven by chemical gradients in pore water and might lead to mineralogical modifications in both materials. In the context of a radioactive waste repository, this alteration might influence safety-relevant clay properties like swelling pressure, permeability, or specific retention. In this study, interfaces of Opalinus Clay, a potential host-rock in Switzerland, and three concrete formulations emplaced in the Cement-Clay Interaction (CI) Experiment at the Mont Terri Underground Laboratory (St. Ursanne, Switzerland) were analysed after 2.2 years of interaction. Sampling techniques with interface stabilisation followed by inclined intersection drilling were developed. Element distribution maps of the concrete-clay interfaces show complex zonations like sulphur enrichment, zones depleted in Ca but enriched in Mg, strong Mg enrichment adjacent to the interface, or carbonation. Consistently, the carbonated zone shows a reduced porosity. Properties of the complex zonation strongly depend on cement properties like water content and pH (ordinary Portland cement vs. low-pH cement). An increased Ca or Mg content in the first 100 μm next to the interface is observed in Opalinus Clay. The cation occupancy of clay exchanger phases next to the ordinary Portland cement interface is depleted in Mg, but enriched in Na, whereas porosity shows no changes at all. The current data suggests migration of CO2/HCO3-, SO42-, and Mg species from clay into cement. pH decrease in the cement next to the interface leads to instability of ettringite, and the sulphate liberated diffuses towards higher pH regions (away from the interface), where additional ettringite can form.

  20. Diffusion, sorption and stability of radionuclide-organic complexes in clays and clay-organic complexes

    International Nuclear Information System (INIS)

    The dependence on various parameters of the diffusion coefficient of neptunium (V) in clay systems has been studied. The effect of the clay mineralogy, the charge compensating cation in the clay, the ionic strength of a background perchlorate solution and the presence of three organic ligands have been investigated. The diffusion coefficients were compared to those predicted if diffusion occurred only in the liquid phase and adsorption was reversible; agreement was fairly good. An approximation to the diffusion coefficient can thus be obtained from readily measured experimental parameters. There is no evidence of surface phase diffusion. The most significant factor in determining the diffusion coefficient is the magnitude of the distribution ratio, itself highly dependent on the nature of the clay. Neither EDTA nor citrate modified the diffusion coefficient. Although the presence of 1 or 100 mg dm-3 of Aldrich humic acid had little effect on the distribution ratio of neptunium, it caused a lowering of the measured diffusion coefficient. This is interpreted in terms of the limiting liquid phase diffusion coefficient and the true liquid phase impedance factor of neptunium-humic acid complexes. 21 figs; 3 tabs; 20 refs

  1. Charm of Purple Clay A private museum in Wuxi is devoted to purple-clay art

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Purple-clay art pieces will be on display in a museum opening soon in Wuxi, Jiangsu Province. The museum, named Shuaiyuan Purple Clay Museum, is part of the Shuaiyuan Purple Clay Art Exhibition Center

  2. Synthesis and characterization of nanocomposites based on polyurethane in aqueous dispersions with non-modified hydrophilic clays; Sintese e caracterizacao de nanocompositos a base de poliuretanos em dispersoes aquosas com argilas hidrofilicas nao-modificadas

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, G.S.; Delpechi, M.C.; Santo, W.L.E., E-mail: mcd@uerj.b [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2010-07-01

    Several studies involving the formation of polyurethane nanocomposites employing clays of montmorillonite modified. This involves the presence of quaternary ammonium salts, the cation exchange needed to increase the interlayer space of clays that incorporate more than one step to the process, generates a higher cost. In this paper the synthesis of nanocomposite polyurethanes dispersed in water allowed not only the production of materials less harmful to the environment, but also the incorporation of hydrophilic clays, calcium and sodium in nature, without any modifications. Dispersions produced from 0.5, 1.0 and 2.5% clay (on the mass of prepolymer) were characterized in terms of total solids content, the films obtained by casting were evaluated for adhesiveness, diffraction X-rays, scanning electron microscopy. Most systems showed intercalated and partially exfoliated structures. (author)

  3. Water Resources Compound Systems: A Macro Approach to Analysing Water Resource Issues under Changing Situations

    OpenAIRE

    Wei Wang; Deshan Tang; Melissa Pilgrim; Jinan Liu

    2015-01-01

    Water resource crises are an increasing threat to human survival and development. To reveal the nature of water resource issues under changing situations, the water resources system needs to be studied from a macro and systematic perspective. This report develops a water resources system into a water resources compound system that is constantly evolving under the combined action of the development, resistant, and coordination mechanisms. Additionally, the water quotient is defined as a quanti...

  4. Operator Support System for Pressurized Water Reactor

    International Nuclear Information System (INIS)

    Operator Support System for Pressurized Water Reactor (OSSPWR) has been developed under the sponsorship of IAEA from August 1994. The project is being carried out by the Department of Engineering Physics, Tsinghua University, Beijing, China. The Design concepts of the operator support functions have been established. The prototype systems of OSSPWR has been developed as well. The primary goal of the project is to create an advanced operator support system by applying new technologies such as artificial intelligence (AI) techniques, advanced communication technologies, etc. Recently, the advanced man-machine interface for nuclear power plant operators has been developed. It is connected to the modern computer systems and utilizes new high performance graphic displays. (author). 6 refs, 4 figs

  5. Controlling suction by vapour equilibrium technique at different temperatures, application to the determination of the water retention properties of MX80 clay

    CERN Document Server

    Tang, Anh-Minh

    2005-01-01

    Problems related to unsaturated soils are frequently encountered in geotechnical or environmental engineering works. In most cases, for the purpose of simplicity, the problems are studied by considering the suction effects on volume change or shear strength under isothermal conditions. Under isothermal condition, very often, a temperature independent water retention curve is considered in the analysis, which is obviously a simplification. When the temperature changes are too significant to be neglected, it is necessary to account for the thermal effects. In this paper, a method for controlling suction using the vapour equilibrium technique at different temperatures is presented. First, calibration of various saturated saline solutions was carried out from temperature of 20 degrees C to 60 degrees C. A mirror psychrometer was used for the measurement of relative humidity generated by saturated saline solutions at different temperatures. The results obtained are in good agreement with the data from the literatu...

  6. Electrochemical anomalies of protic ionic liquid - Water systems: A case study using ethylammonium nitrate - Water system

    Science.gov (United States)

    Abe, Hiroshi; Nakama, Kazuya; Hayashi, Ryotaro; Aono, Masami; Takekiyo, Takahiro; Yoshimura, Yukihiro; Saihara, Koji; Shimizu, Akio

    2016-08-01

    Electrochemical impedance spectroscopy was used to evaluate protic ionic liquid (pIL)-water mixtures in the temperature range of -35-25 °C. The pIL used in this study was ethylammonium nitrate (EAN). At room temperature, the resonant mode of conductivity was observed in the high frequency region. The anomalous conductivity disappeared once solidification occurred at low temperatures. The kinetic pH of the EAN-water system was investigated at a fixed temperature. Rhythmic pH oscillations in the EAN-H2O mixtures were induced at 70 water mixture are caused in an intermediate state between pIL and bulk water. From the ab initio calculations, it was observed that the dipole moment of the EAN-water complex shows a discrete jump at around 85 mol% H2O. Water-mediated hydrogen bonding network drastically changes at the crossover concentration.

  7. Development of polymer nanocomposites with regional bentonite clay; Desenvolvimento de nanocompositos polimericos com argila bentonitica regional

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Edcleide M.; Leite, Amanda M.D.; Paz, Rene A. da; Medeiros, Keila M. de; Melo, Tomas J.A., E-mail: edcleide@dema.ufcg.edu.br [Unidade Academica de Engenharia de Materiais da UFCG, Campina Grande, PB (Brazil); Barbosa, Josiane D.V. [SENAI/CIMATEC, Salvador, BA (Brazil); Barbosa, Renata [Universidade Federal do Piaui, UFPI, Teresina, PI (Brazil)

    2011-07-01

    nanocomposites with regional bentonite clay were prepared by melt intercalation technique. The clays were studied without modification and modified with four quaternary ammonium salts. It was evidenced by X-ray diffraction that salts were incorporated into the clay structure thus confirming its organophilization. The nanocomposites were evaluated by means of thermal mechanic and flammability tests where presented properties significantly improved their pure polymers. The process of biodegradation of obtained bio nanocomposites was accelerated by the presence of clay. The produced membranes from nanocomposites have potential in the oil-water separation. (author)

  8. Prediction of Settlements of Soft Clay Subjected to Long-Term Dynamic Load

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    -Presented is the numerical analysis of settlements of soft soil by a 2-D dynamic effective stress FEM method. The model based on the results of cyclic triaxial tests on the reconstituted soft Ariake clay is used to predict the wave induced excess pore water pressure and residual strain of soft clay. The settlements of two types of breakwaters on the soft clay under ocean wave load, a low embankment subjected to traffic load and the tunnel surrounded by soft clay in Shanghai subjected to locomotive load are calculated as examples.

  9. Clay dispersibility and soil friability – testing the soil clay-to-carbon saturation concept

    OpenAIRE

    Schjønning, P.; de Jonge, L. W.; Munkholm, L.J.; P. Moldrup; B. T. Christensen; Olesen, J.E.

    2011-01-01

    Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC as a predictor of clay dispersibility and soil friability. Soil was sampled three years in a field varying in clay content (~100 to ~220 g kg-1 soil) and grown with different crop rotations. Clay ...

  10. Modelling the thermo-mechanical volume change behaviour of compacted expansive clays

    CERN Document Server

    Tang, Anh-Minh; 10.1680/geot.2009.59.3.185

    2009-01-01

    Compacted expansive clays are often considered as a possible buffer material in high-level deep radioactive waste disposals. After the installation of waste canisters, the engineered clay barriers are subjected to thermo-hydro-mechanical actions in the form of water infiltration from the geological barrier, heat dissipation from the radioactive waste canisters, and stresses generated by clay swelling under almost confined conditions. The aim of the present work is to develop a constitutive model that is able to describe the behaviour of compacted expansive clays under these coupled thermo-hydro-mechanical actions. The proposed model is based on two existing models: one for the hydro-mechanical behaviour of compacted expansive clays and another for the thermo-mechanical behaviour of saturated clays. The elaborated model has been validated using the thermo-hydro-mechanical test results on the compacted MX80 bentonite. Comparison between the model prediction and the experimental data show that this model is able...

  11. Nafion–clay hybrids with a network structure

    KAUST Repository

    Burgaz, Engin

    2009-05-01

    Nafion-clay hybrid membranes with a unique microstructure were synthesized using a fundamentally new approach. The new approach is based on depletion aggregation of suspended particles - a well-known phenomenon in colloids. For certain concentrations of clay and polymer, addition of Nafion solution to clay suspensions in water leads to a gel. Using Cryo-TEM we show that the clay particles in the hybrid gels form a network structure with an average cell size in the order of 500 nm. The hybrid gels are subsequently cast to produce hybrid Nafion-clay membranes. Compared to pure Nafion the swelling of the hybrid membranes in water and methanol is dramatically reduced while their selectivity (ratio of conductivity over permeability) increases. The small decrease of ionic conductivity for the hybrid membranes is more than compensated by the large decrease in methanol permeability. Lastly the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion. Both of these characteristics are highly desirable for use in fuel cell applications, since a) they will allow the use of a thinner membrane circumventing problems associated with the membrane resistance and b) enable high temperature applications. © 2009 Elsevier Ltd. All rights reserved.

  12. Solubility limited retention of strontium in boom clay

    International Nuclear Information System (INIS)

    For over 25 years, the study of Boom Clay as a geological barrier to radioactive waste has focused on laboratory batch type and diffusion experiments using artificial tracers. These experiments may suffer from artefacts and are not always representative for natural conditions and the geological time scale. Only in recent years, the research has significantly taken natural evidences into account. An important objective of the natural evidence study is to test the models representing the retention of radionuclides by confronting the observed distribution of naturally present radionuclides. The distribution and retention of naturally present strontium in Boom Clay was studied for clay cores from recent drillings in HADES (Underground Research Facilities) 2001/4 and Mol-1 boreholes. The concentration of strontium was measured both on solid clay and in pore water extracted by mechanical squeezing from the clay cores. Strontium concentration was also determined in the pore water samples collected from a multi-filter piezometer installed in the HADES 2001/4 borehole. (authors)

  13. Permeability response of oil-contaminated compacted clays

    International Nuclear Information System (INIS)

    This paper presents the results of a laboratory investigation on the behavior of motor oil-contaminated, partially saturated compacted clays. For the study, both a natural clay and an artificially purified kaolinite, contaminated with 0 to 8% of motor oil, were firstly compacted following the ASTM standard procedure. Secondly, permeability tests were carried out in a triaxial cell on 10 cm-diameter compacted clay specimens. The results of the investigation indicate that increasing percentages of motor oil decrease both the optimum water content and the optimum dry density of the two clays. However, whereas the optimum water content on the average decreases by about 6% when the percentage contamination increases from 0 to 8%, the corresponding decrease in the optimum dry density is less than 3%. Even though the optimum dry density decreases as the percentage of oil increases from 0 to 8%, there is, however, a range in oil content varying between 2 and 4% for which the optimum dry density is slightly greater than that of the untreated soils. As far as the permeability tests are concerned, the results indicate that as the percentage of oil increases, the coefficient of permeability decreases substantially, especially for clay specimens which were initially compacted on the dry side of optimum

  14. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    example, the excavation-damaged zone (EDZ) near repository tunnels can modify local permeability (resulting from induced fractures), potentially leading to less confinement capability (Tsang et al., 2005). Because of clay's swelling and shrinkage behavior (depending on whether the clay is in imbibition or drainage processes), fracture properties in the EDZ are quite dynamic and evolve over time as hydromechanical conditions change. To understand and model the coupled processes and their impact on repository performance is critical for the defensible performance assessment of a clay repository. Within the Natural Barrier System (NBS) group of the Used Fuel Disposition (UFD) Campaign at DOE's Office of Nuclear Energy, LBNL's research activities have focused on understanding and modeling such coupled processes. LBNL provided a report in this April on literature survey of studies on coupled processes in clay repositories and identification of technical issues and knowledge gaps (Tsang et al., 2010). This report will document other LBNL research activities within the natural system work package, including the development of constitutive relationships for elastic deformation of clay rock (Section 2), a THM modeling study (Section 3) and a THC modeling study (Section 4). The purpose of the THM and THC modeling studies is to demonstrate the current modeling capabilities in dealing with coupled processes in a potential clay repository. In Section 5, we discuss potential future R and D work based on the identified knowledge gaps. The linkage between these activities and related FEPs is presented in Section 6.

  15. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

    2010-08-31

    example, the excavation-damaged zone (EDZ) near repository tunnels can modify local permeability (resulting from induced fractures), potentially leading to less confinement capability (Tsang et al., 2005). Because of clay's swelling and shrinkage behavior (depending on whether the clay is in imbibition or drainage processes), fracture properties in the EDZ are quite dynamic and evolve over time as hydromechanical conditions change. To understand and model the coupled processes and their impact on repository performance is critical for the defensible performance assessment of a clay repository. Within the Natural Barrier System (NBS) group of the Used Fuel Disposition (UFD) Campaign at DOE's Office of Nuclear Energy, LBNL's research activities have focused on understanding and modeling such coupled processes. LBNL provided a report in this April on literature survey of studies on coupled processes in clay repositories and identification of technical issues and knowledge gaps (Tsang et al., 2010). This report will document other LBNL research activities within the natural system work package, including the development of constitutive relationships for elastic deformation of clay rock (Section 2), a THM modeling study (Section 3) and a THC modeling study (Section 4). The purpose of the THM and THC modeling studies is to demonstrate the current modeling capabilities in dealing with coupled processes in a potential clay repository. In Section 5, we discuss potential future R&D work based on the identified knowledge gaps. The linkage between these activities and related FEPs is presented in Section 6.

  16. AlFe层柱粘土催化剂催化甲苯在水中的降解%Toluene Degradation in Water Using AlFe-Pillared Clay Catalysts

    Institute of Scientific and Technical Information of China (English)

    Predrag BANKOVI(C); Aleksandra MILUTINOVI(C)-NIKOLI(C); Zorica MOJOVI(C); Aleksandra ROSI(C); (Z)eljko (C)UPI(C); Davor LON(C)AREVI(C); Du(s)an JOVANOVI(C)

    2009-01-01

    The catalytic wet peroxide oxidation (CWPO) of toluene on two bentonite-based AlFe-pillared clays (PILCs) with different iron contents was investigated. The PILCs were obtained using bentonite clay from Bogovina, Serbia. The change in chemical and phase composition and textural properties of the starting clay and synthesized catalysts was monitored using X-ray diffraction, inductively coupled plasma optical emission spectrometry, UV-Vis diffuse reflectance spectrometry, and physisorption of nitrogen. The catalytic performance was examined using gas chromatography. The Na-exchange process lowered the (001) smectite basal plane spacing, but the clay retained its swelling properties, while the pillaring process increased it. The surface areas of both synthesized pillared clays increased to similar values although their Fe content was different. At 37 ℃, both catalysts show significant toluene degradation, with the one richer in Fe having higher efficiency. The leaching of the active cations during reaction was negligible, and the catalysts were stable. AlFe-pillared clay catalysts can be used in CWPO for the elimination of BTEX compounds from plant effluent streams.

  17. Water barrier properties of starch-clay nanocomposite films Propriedades de barreira à água de filmes de nanocompósitos de amido e argila

    Directory of Open Access Journals (Sweden)

    Aníbal Marcelo Slavutsky

    2012-09-01

    Full Text Available The functional properties of corn starch based films were improved by incorporating nanoclay (Montmorillonite. Nanoclay was incorporated in the polymer matrix using two different methodologies and the films were formed by casting. The effect of film preparation methodology and of the nanoclay concentration on the physicochemical properties of the films was studied. Depending on film preparation method used, intercalated or exfoliated nanocomposite films were obtained. The FTIR spectra showed a strong interaction between the montmorillonite and the starch molecules. Opacity was dependent on the nanoclay dispersion method used. Water vapor solubility and permeability decreased with increasing montmorillonite content and were affected by the dispersion method. Water diffusion was only dependent on the nanoclay content due to the increase in tortuosity of the diffusion path, caused by the nanoparticles. The results showed that the incorporation of 5% of montmorillonite using an adequate dispersion method, improved the water resistance and barrier properties of corn starch based films. Nanoparticles reduced the damage caused to the properties of these hydrophilic films by the increase in moisture content.As propriedades funcionais de filmes à base de amido de milho foram melhoradas pela incorporação de nanoargila (montmorilonita. Nanoargila foi incorporada na matriz polimérica por meio de duas metodologias diferentes e os filmes foram produzidos por casting. Os efeitos da metodologia de preparação e da concentração de nanoargila nas propriedades físico-químicas dos filmes foram estudados. Conforme os métodos de elaboração, filmes intercalados e esfoliados de nanocompósitos foram obtidos. Os espectros FTIR mostraram uma forte interação entre a argila montmorilonita e as moléculas de amido. A opacidade foi dependente do método utilizado para a dispersão da nanoargila. A solubilidade e a permeabilidade ao vapor de água diminu

  18. Simulation and model comparison of unsaturated movement of pesticides from a large clay lysimeter.

    NARCIS (Netherlands)

    Vink, J.P.M.; Gottesbüren, B.; Diekkrüger, B.; Zee, van der S.E.A.T.M.

    1997-01-01

    A long-term (>10 months) leaching experiment was conducted with a large clay soil column and a rain simulator to study unsaturated transport of the nematicide aldicarb and the herbicide simazine in a cracked clay soil. Water retention and soil conductivity were derived from experimental outflow data

  19. Revealing Soil Structure and Functional Macroporosity along a Clay Gradient Using X-ray Computed Tomography

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Arthur, Emmanuel;

    2013-01-01

    clay content, respectively) at a field site in Lerbjerg, Denmark. The water-holding capacity of soils markedly increased with increasing soil clay content, while significantly higher air permeability was observed for the L1 to L3 soils than for the L4 to L6 soils. Higher air permeability values...

  20. Magnitude, modeling and significance of swelling and shrinkage processes in clay soils.

    NARCIS (Netherlands)

    Bronswijk, J.J.B.

    1991-01-01

    The dynamic process of swelling and shrinkage in clay soils has significant practical consequences, such as the rapid transport of water and solutes via shrinkage cracks to the subsoil, and the destruction of buildings and roads on clay soils. In order to develop measuring methods and computer simul

  1. Tectonic?palaeoenvironmental forcing of clay-mineral assemblages in nonmarine settings: the Oligocene?Miocene As Pontes Basin (Spain)

    Science.gov (United States)

    Sáez, A.; Inglès, M.; Cabrera, L.; de las Heras, A.

    2003-07-01

    rather diverse clay compositions. This clearly reflects the influence on clay assemblages of palaeoenvironmental changes forced by the morphological and tectonic evolution of the catchment-basin system. The interplay between climate and tectonic processes in the source areas did not result in major variations of the clay minerals fed into the basin. Conversely, this tectonic-sedimentation interplay influenced the evolution of the drainage and the water balance in the depositional zones, causing a complex environmental-hydrochemical evolution to occur. As a consequence, drastic early diagenetic changes affected the original clay mineral assemblages and resulted in a variety of early diagenetic assemblages. The As Pontes case study emphasises the major influence of palaeogeographical and tectonosedimentary evolution on the clay mineral record in nonmarine depositional systems. The depositional record in As Pontes Basin demonstrates that morphological and tectonically forced environmental and hydrochemical changes can result in variations similar to those forced by low-order climatic changes and that, in some cases, the role of climate can be negligible.

  2. Fluoride retention by kaolin clay

    DEFF Research Database (Denmark)

    Kau, P. M. H.; Smith, D. W.; Binning, Philip John

    1997-01-01

    To evaluate the potential effectiveness of kaolin clay liners in storage of fluoride contaminated waste, an experimental study of the sorption and desorption behaviour of fluoride in kaolin clay was conducted. The degree of fluoride sorption by kaolin was found to depend on solution p......H and available fluoride concentration with equilibrium being achieved within 24 h. A site activation process involving the uptake of fluoride was also observed at the initial stages of sorption. This behaviour was attributed to a layer expansion process of the clay during sorption. The maximum fluoride sorption...... capacity was found to be 18.3 meq/100 g at pH 6 and 8.6 meq/100 g at pH 7. A competitive Langmuir sorption isotherm where sorption is dependant on both pH and fluoride concentration is employed to characterise the experimental sorption and desorption data. The sorption and desorption isotherms revealed...

  3. Columbia River system operations - water quality assessment

    International Nuclear Information System (INIS)

    In mid-1990, the U.S. Army Corps of Engineers, U.S. Bureau of Reclamation, and Bonneville Power Administration embarked on a Columbia River system operation review (SOR). The goal of the SOR is to establish an updated operation strategy which best recognizes the various river uses as identified through community input. Ninety alternative operations of the Columbia and Snake River systems were proposed by various users. These users included the general public, irrigation and utility districts, as well as local, state and various Federal government agencies involved with specific water resource interests in the Columbia River basin. Ten technical work groups were formed to cover the spectrum of interest and to evaluate the alternative operations. Using simplified tools and risk-based analysis, each work group analyzed and then ranked the alternatives according to the effect on the work group's specific interest. The focus of the water quality technical work group is the impact assessment, on water quality and dissolved gas saturation, of the various operations proposed by special interests (i.e., hydropower, navigation, flood control, irrigation, recreation, cultural resources, wildlife, and anadromous and resident fisheries)

  4. Porous networks derived from synthetic polymer-clay complexes

    Energy Technology Data Exchange (ETDEWEB)

    Carrado, K.A.; Thiyagarajan, P.; Elder, D.L.

    1995-05-12

    Synthetic hectorites were hydrothermally crystallized with direct incorporation of a cationic polymer poly(dimethyl diallyl ammonium chloride) (PDDA), and two neutral cellulosic polymers hydroxypropyl methylcellulose (HPMC) and hydroxyethyl cellulose (HEC). Synthetic PDDA-hectorite displays the lowest d-spacing at 15.8 {Angstrom} along with less polymer incorporation (7.8 wt % organic) than the neutral polymers (18--22 wt % organic). Thermal analysis and small angle neutron scattering were used to further examine the polymer-clay systems. Clay platelets of the largest size and best stacking order occur when cationic PDDA polymer is used. PDDA also enhances these properties over the crystallites prepared for a control mineral, where no polymer is used. HEC acts to aggregate the silica, leaving less to react to form clay. The clay platelets which result from HEC are small, not stacked to a large degree, and oriented randomly. Neutral HPMC acts more like cationic PDDA in that larger clay platelets are allowed to form. The extended microstructure of the clay network remains undisturbed after polymer is removed by calcination. When no polymer is used, the synthetic hectorite has a N{sub 2} BET surface area of 200 M{sup 2}/gm, even after calcination. This increases by 20--50% for the synthetic polymer-hectorites after the polymer is removed by calcination.

  5. Synchrotron X-ray Scattering from Self-organized Soft Nanostructures in Clays

    Science.gov (United States)

    Fossum, J. O.

    2009-04-01

    In the general context of self-organization of nanoparticles (in our case clay particles), and transitions in such structures, we study interconnected universal complex physical phenomena such as: (i) spontaneous gravitationally induced phase separation and nematic self-organization in systems of anisotropic clay nanoparticles in aqueous suspension, including studies of isotropic to nematic transitions [1,2] (ii) transitions from biaxial to uniaxial nematics by application of external magnetic field to self-organized systems of the same anisotropic (diamagnetic) clay nanoparticle systems [3,4] (iii) guided self-organization into chainlike structures of the same anisotropic clay nanoparticles in oil suspension when subjected to external electrical fields (electrorheological structures of polarized nanoparticles), and the stability of, and transitions of, such structures, when subjected to external mechanical stress [5,6] The experimental techniques used by us include synchrotron X-ray scattering, neutron scattering, rheometry. microscopy and magnetic resonance. We have demonstrated that clays may be used as good model systems for studies of universal physical phenomena and transitions in self-organized nanostructured soft and complex matter. Self-organization and related transitions in clay systems in particular, may have practical relevance for nano-patterning, properties of nanocomposites, and macroscopically anisotropic gels, among many other applications [7]. The synchrotron experiments have been performed at LNLS-Brazil, PLS- Korea, BNL-USA and ESRF-France. Acknowledgments: Collaborators, postdocs and students at NTNU-Norway, UiO-Norway, IFE-Norway, BNL-USA, LNLS-Brazil, UFPE-Brazil, UnB-Brazil, Univ. Amsterdam-Netherlands, Univ.Paris 7-France and other places. This research has been supported by the Research Council of Norway (RCN), through the NANOMAT, SUP and FRINAT Programs. References 1. J.O. Fossum, E. Gudding, D.d.M. Fonseca, Y. Meheust, E. DiMasi, T

  6. Boron enrichment in martian clay.

    Science.gov (United States)

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  7. Boron enrichment in martian clay.

    Directory of Open Access Journals (Sweden)

    James D Stephenson

    Full Text Available We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  8. Freezing phenomena in ice-water systems

    Energy Technology Data Exchange (ETDEWEB)

    Akyurt, M.; Zaki, G.; Habeebullah, B. [Fakieh Center for Applied Research, Makkah Al-Mukarramah (Saudi Arabia); King Abdulaziz University, Jeddah (Saudi Arabia). Dept. of Mechanical Engineering

    2002-09-01

    The characteristics of solidification and melting are reviewed. The properties of water and ice and the phase diagram of water are discussed with special emphasis on ice density. A concise account of the freezing process and the Stefan problem is presented. To this end, the four stages of freezing are identified, supercooling, nucleation and the formation of dendritic ice, the growth of concentric rings of solid ice at 0{sup o}C and the final cooling of the solid ice are treated in some detail. The subject of bursting of pipes is given particular emphasis. Attention is drawn to a common misconception on pipe bursting and to misleading relationships for the computation of freezing time for ice blockage. Several current applications of melting and freezing systems are outlined. (author)

  9. Imaging techniques in clay sciences: a key tool to go a step further

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Clay-rocks and clay based materials are greatly considered in nuclear waste geological repository due to their multiple favourable properties (low permeability, low diffusion coefficients, high retention capacity for radionuclides, swelling...). In this context, the study of clays and clay rocks covers a large variety of scientific disciplines such as geology, mineralogy, geomechanics, geochemistry or hydrodynamics. These disciplines are linked together by a common issue which is the understanding and the predicting of clay and clay-rock behaviors and properties under various thermal-hydrological-mechanical- chemical (THMC) conditions. Linking the fundamental forces to macroscopic (from millimeter to several meters) behaviors and properties is nevertheless not straightforward for porous media such as clay-rocks and clay based materials. Currently, it remains a key challenge for the scientific community. Imaging techniques offer solutions to face up this challenge by characterizing the internal microstructure of material and rocks at different levels of resolution. Due to the reactivity of clay minerals with water (swelling, mechanical deformation) or with repository components (mineral transformations at iron, copper or concrete interfaces) and the multi-scale distribution of pore and mineral sizes, classically ranged from nano-meter to millimeter, imaging clay based materials and clay-rocks itself is unanimously recognized as a challenging task. In the 80's, despite several constraints and limits, the microstructure of clays had been intensively imaged using conventional 2D imaging techniques such as optical microscopy, X-ray radiography, scanning electron microscopy or transmission electron microscopy [1]. The images acquired using these techniques have given us a pictorial frame of reference of the internal structures of clay rocks and clay based materials at various resolution levels. They have also highlighted

  10. Model Predictive Control of Skeboå Water system

    OpenAIRE

    Gabrielsson, Fredrik

    2012-01-01

    This thesis is a study of model predictive control of water levels and flows in a water system. The water system studied includes five lakes and six dams that are regulated manually by sluice-gates. The water is used in the papermaking process at Holmen Paper Mill in Hallstavik. The aim of this thesis is to find out how to control the water system when all dams are automated and to minimize the discharge of water from the system without risking production stops due to water shortage. To fulfi...

  11. Clay pot irrigation for tomato (Lycopersicon esculentum Mill production in the north east semiarid region of Ethiopia

    Directory of Open Access Journals (Sweden)

    Kebede Woldetsadik

    2011-06-01

    Full Text Available Water shortage is one of the major constraints for production of horticultural crops in arid and semiarid regions. A field experiment was conducted to determine irrigation water and fertilizer use efficiency, growth and yield of tomato under clay pot irrigation at the experimental site of Sekota Dryland Agricultural Research Center, Lalibela, Ethiopia in 2009/10. The experiment comprised of five treatments including furrow irrigated control and clay pot irrigation with different plant population and fertilization methods, which were arranged in Randomized Complete Block Design with three replications. The highest total and marketable fruit yields were obtained from clay pot irrigation combined with application of nitrogen fertilizer with irrigation water irrespective of difference in plant population. The clay pot irrigation had seasonal water use of up to 143.71 mm, which resulted in significantly higher water use efficiency (33.62 kg m-3 as compared to the furrow irrigation, which had a seasonal water use of 485.50 mm, and a water use efficiency of 6.67 kg m-3. Application of nitrogen fertilizer with irrigation water in clay pots improved fertilizer use efficiency of tomato by up to 52% than band application with furrow or clay pot irrigation. Thus, clay pot irrigation with 33,333 plants ha-1 and nitrogen fertilizer application with irrigation water in clay pots was the best method for increasing the yield of tomato while economizing the use of water and nitrogen fertilizer in a semiarid environment.

  12. Nano sized clay detected on chalk particle surfaces

    DEFF Research Database (Denmark)

    Skovbjerg, Lone; Hassenkam, Tue; Makovicky, Emil;

    2012-01-01

    that in calcite saturated water, both the polar and the nonpolar functional groups adhere to the nano sized clay particles but not to calcite. This is fundamentally important information for the development of conceptual and chemical models to explain wettability alterations in chalk reservoirs...

  13. Derivation of in situ opalinus clay porewater compositions from experimental and geochemical modelling studies

    International Nuclear Information System (INIS)

    Many countries are considering argillaceous sedimentary rocks as potential formations for the disposal of high level radioactive waste. One of the main attractions of such formations from a waste management viewpoint are their generally low groundwater flow rates. However, porewater chemistry constitutes an important basic data set for performance assessment studies and the low transmissivities often mean that it is very difficult, or even impossible, to obtain good in situ water samples. This report describes procedures based on physico-chemical characterisation of whole rock samples and geochemical modelling which were developed as an additional tool for determining porewater compositions in low porosity/permeability clay rich systems. The methodology was applied to core samples of opalinus clay within the framework of an international investigation being carried out at Mt. Terri, Canton Jura, Switzerland. The calculated porewater compositions are described and discussed in relation to experimental data from the analyses of borehole seepage water and water samples obtained from squeezing tests. Because the latter two waters were clearly out of the equilibrium, only a comparison based on general aqueous features was attempted. In all three cases the groundwaters were high ionic strength Na-Cl types. The experimentally determined pH values were in the range 7.5-8 whereas for the modelled porewater a value near 6 was calculated. This discrepancy was explained by postulating that the sampled waters lost dissolved CO2 through out-gassing. (author) 5 figs., 11 tabs., refs

  14. Water Renew systems: wastewater polishing using renewable energy crops.

    Science.gov (United States)

    Sugiura, A; Tyrrel, S F; Seymour, I; Burgess, P J

    2008-01-01

    Macronutrients concentrations were measured during the establishment year of short rotation coppice of Salix vim