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Sample records for clays 44th annual

  1. Enchanted Clays: 44th Annual Meeting of the Clay Minerals Society (June 2007)

    Energy Technology Data Exchange (ETDEWEB)

    Randall T. Cygan

    2007-06-01

    “Enchanted Clays: 44th Annual Meeting of the Clay Minerals Society” was held in early June 2007 in beautiful and historic Santa Fe, New Mexico, USA. Santa Fe provided an idyllic location in the southwestern United States for the attendees to enjoy technical and social sessions while soaking up the diverse culture and wonderful climate of New Mexico—The Land of Enchantment. The meeting included a large and varied group of scientists, sharing knowledge and ideas, benefitting from technical interactions, and enjoying the wonderful historic and enchanted environs of Santa Fe. Including significant number of international scientists, the meeting was attended by approximately two hundred participants. The meeting included three days of technical sessions (oral and poster presentations), three days of field trips to clay and geological sites of northern New Mexico, and a full day workshop on the stabilization of carbon by clays. Details can be found at the meeting web site: www.sandia.gov/clay.

  2. 44th Annual Anomalous Absorption Conference

    Energy Technology Data Exchange (ETDEWEB)

    Beg, Farhat

    2014-03-03

    Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded

  3. Program and Abstracts for Clay Minerals Society 28th Annual Meeting

    Science.gov (United States)

    1991-01-01

    This volume contains abstracts that were accepted for presentation at the annual meeting. Some of the main topics covered include: (1) fundamental properties of minerals and methods of mineral analysis; (2) surface chemistry; (3) extraterrestrial clay minerals; (4) geothermometers and geochronometers; (5) smectite, vermiculite, illite, and related reactions; (6) soils and clays in environmental research; (7) kaolinite, halloysite, iron oxides, and mineral transformations; and (8) clays in lakes, basins, and reservoirs.

  4. The 44th success of the CERN Relay Race

    CERN Multimedia

    Anaïs Schaeffer

    2014-01-01

    On Thursday 5 June, 590 people (8 Nordic walkers and 97 teams of 6 runners each) took part in the 44th CERN Relay Race.   The teams were divided into 8 different categories: mixed, mixed open, women, women open, men, men open, men veterans and Nordic Walk. The participants covered 3,900 metres around the Meyrin site, with the race's winners covering this distance in only 11 minutes and 4 seconds! (See all the results here.) All the participants received a souvenir prize and the winners of each category took home a trophy. Additional prizes were given to the winners of the 1000 m challenge and Challenge Entreprise, and to the best CERN Users and Associates team, Department team and fancy dress team. Everybody had a very good time, thanks to the excellent weather and the dynamic and friendly atmosphere created by the CERN Clubs! The Running Club would like to thank the Staff Association, the CERN Management and services, the event’s sponsors and, especially, all the volunteers...

  5. 44th Plenary Meeting Report of the Scientific, Technical and Economic Committee for Fisheries (PLEN-13-03)

    DEFF Research Database (Denmark)

    Casey, J.; Abella, J. A.; Andersen, J.; Bailey, N.; Bertignac, M.; Cardinale, M.; Curtis, H.; Daskalov, G.; Delaney, Alyne; Döring, R.; Garcia Rodriguez, M.; Gascuel, D.; Graham, N.; Gustavsson,, T.; Jennings, S.; Kenny, A.; Kirkegaard, E.; Kraak, S.; Kuikka, S.; Malvarosa, L.; Martin, P.; Murua, H.; Nord, J.; Nowakowski, P.; Prellezo, R.; Sala, A.; Scarcella, G.; Somarakis, S.; Stransky, C.; Theret, F.; Ulrich, C.; Vanhee, W.; Van Oostenbrugge, H.

    The Scientific, Technical and Economic Committee for Fisheries hold its 44th plenary on 4-8 November 2013 in Brussels (Belgium). The terms of reference included both issues assessments of STECF Expert Working Group reports and additional requests submitted to the STECF by the Commission. Topics...... dealt were inter alia assessments of the economic performance of the EU aquaculture and fish processing sectors, fishing effort regime evaluations, and review of stock advice....

  6. Report on the 44th International Symposium: Actual Tasks on Agricultural Engineering, 23rd-26th February 2016, Opatija, Croatia

    Directory of Open Access Journals (Sweden)

    Igor Kovačev

    2016-03-01

    Full Text Available The 44th International Symposium Actual Tasks on Agricultural Engineering was held on 23rd-26th February 2016 in Grand Hotel Adriatic Opatija, Republic of Croatia. The principle Organiser, Agricultural Engineering Department, Faculty of Agriculture, University of Zagreb was supported by the following frameworks: Department of Agricultural Engineering, Faculty of Agriculture, University J.J. Strossmayer, Osijek, Department of Bio-systems Engineering, Faculty of Agriculture and Lifesciences, University of Maribor (Slovenia, Agricultural Institute of Slovenia, National institute for agricultural machinery - INMA Bucharest (Romania and Croatian Agricultural Engineering Society. In addition, CIGR, EurAgEng and AAAE bestowed their support and endorsement on the Event.

  7. 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.

  8. Polyethylene/clay nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Měřínská, D.; Kovářová, L.; Kalendová, A.; Chmielová, M.; Weiss, Z.; Hromádková, Jiřina; Šimoník, J.

    Akron: Polymer Processing Society, 2004. s. 245. [Polymer Processing Society Annual Meeting. 20.06.2004-24.06.2004, Akron] R&D Projects: GA AV ČR KSK4050111 Keywords : polyethylene * clay * polymer nanotechnology Subject RIV: CD - Macromolecular Chemistry

  9. 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.

  10. Clay Minerals and Health

    OpenAIRE

    Abdurrahman Dalgıç; Orhan Kavak

    2004-01-01

    The aim of this study is to examine clay minerals, which take very importantplace in relationships of minerals and human health. They have high areadensity, adsorption capacity, rheological properties, chemical inertia and verylow or nontoxic effects to human health. So, they are widely used in medicaltreatments. Commercially used clay minerals are; smectit, polygrstite, caoliniteand talc. The other clay minerals are under investigations for medicaltreatments.

  11. 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.

  12. 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.

  13. Clay Mineral: Radiological Characterization

    International Nuclear Information System (INIS)

    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. Clays as prebiotic photocatalysts

    Science.gov (United States)

    Coyne, L. M.; Lawless, J.; Lahav, N.; Sutton, S.; Sweeney, M.

    1981-01-01

    Clay minerals catalyze peptide bond formation in fluctuating environments. A number of plausible mechanisms have been proposed and tested. The possibility that clays may actually be energizing the reaction by means of electronic excitation, creating mobile or trapped holes and electrons in the lattice, is explored. It has been discovered that clays emit light upon dehydration. The correlation between dehydration-induced, or thermoluminescent, processes and the yield of glycine oligomers after treatments known to affect the luminescent yields is being tested, in an effort to understand the catalytic mechanism

  15. Characterization of clay minerals

    International Nuclear Information System (INIS)

    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)

  16. Organophilic clay suspension medium

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, G.G.; Parlman, R.M.; Stewart, W.

    1989-10-24

    This patent describes an improved liquid suspension medium for particulate solids. The suspension medium having been formed by admixing an organophilic clay wherein the clay is selected from the group consisting of bentonite, attapulgite, sepiolite and hectorite and admixtures thereof present in the quantity of about 0.5-8 weight percent with a liquid hydrocarbon present in the quantity of about 99-70 weight percent and at least one activator selected from the group consisting of phenyl hydroxyalkyl ethers.

  17. 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

  18. 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...... have been tested successfully. At a natural water content of w=40-45% it is possible to establish a homogeneous membrane with hydraulic conductivity k...

  19. Rattles of Clay.

    Science.gov (United States)

    Banning, Donna

    1983-01-01

    Using the rattles of Native American cultures as inspiration, students used pinching, coiling, and slab and molding techniques to form the bodies of rattles and clay pellets for sound. Surface decoration included glazed and unglazed areas as well as added handles, feathers, and leather. (IS)

  20. Clay matrix voltammetry

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In many countries, it is planned that the long life highly radioactive nuclear spent fuel will be stored in deep argillaceous rocks. The sites selected for this purpose are anoxic and satisfy several recommendations as mechanical stability, low permeability and low redox potential. Pyrite (FeS2), iron(II) carbonate, iron(II) bearing clays and organic matter that are present in very small amounts (about 1% w:w) in soils play a major role in their reactivity and are considered today as responsible for the low redox potential values of these sites. In this communication, we describe an electrochemical technique derived from 'Salt matrix voltammetry' and allowing the almost in-situ voltammetric characterization of air-sensitive samples of soils after the only addition of the minimum humidity required for electrolytic conduction. Figure 1 shows the principle of the developed technique. It consists in the entrapment of the clay sample between a graphite working electrode and a silver counter/quasi-reference electrode. The sample was previously humidified by passing a water saturated inert gas through the electrochemical cell. The technique leads to well-defined voltammetric responses of the electro-active components of the clays. Figure 2 shows a typical voltammogram relative to a Callovo-Oxfordian argillite sample from Bure, the French place planned for the underground nuclear waste disposal. During the direct scan, one can clearly distinguish the anodic voltammetric signals for the oxidation of the iron (II) species associated with the clay and the oxidation of pyrite. The reverse scan displays a small cathodic signal for the reduction of iron (III) associated with the clay that demonstrates that the majority of the previously oxidized iron (II) species were transformed into iron (III) oxides reducible at lower potentials. When a second voltammetric cycle is performed, one can notice that the signal for iron (II

  1. 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…

  2. Clay membrane made of natural high plasticity clay

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1998-01-01

    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 conductivity measured in oedometer tests used for establishing swell and deformation properties showed...

  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...... advective 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...... coefficient being much lower than anticipated using the total porosity. These properties are of major importance to the future use of clay membranes for containment of hazardous waste. In order to explain these properties microstrutural investigations were initiated to establish boundary conditions for...

  4. 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.

  5. 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...

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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 pH and...

  11. 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...

  12. Influence of clay mineralogy on clay based ceramic products

    International Nuclear Information System (INIS)

    Clay-based ceramic products can either be produced directly from a suitable clay source without the need further addition or such products can be produced from a ceramic body formulated by additions of other raw materials such as feldspar and silica sand. In either case, the mineralogical make-up of the clay component plays a dominating role in the fabrication and properties of the ceramic product. This study was sparked off by a peculiar result observed in one of five local ball clay samples that were used to reformulate a ceramic body. Initial characterisation tests conducted on the clays indicated that these clays can be classified as kaolinitic. However, one of these clays produced a ceramic body that is distinctively different in terms of whiteness, smoothness and density as compared to the other four clays. Careful re-examination of other characterisation data, such as particle size distribution and chemical analysis, failed to offer any plausible explanation. Consequently, the mineralogical analysis by x-ray diffraction was repeated by paying meticulous attention to specimen preparation. Diffraction data for the clay with anomalous behaviour indicated the presence of a ∼ 10A peak that diminished when the same specimen was re-tested after heating in an oven at 12O degree C whilst the other four clays only exhibit the characteristic kaolinite (Al sub 2 O sub 3. 2SiO sub 2. 2H sub 2 0) and muscovite peaks at ∼ 7A and ∼ 10A before and after heat treatment. This suggests the presence of the mineral halloysite (A1 sub 2 0 sub 3. 2SiO sub 2.4H sub 2 0) in that particular clay. This difference in mineralogy can be attributed to account for the variations in physical properties of the final product. Consequently, this paper reviews in general the precautionary measures that must be adhered to during any mineralogical investigation of clay minerals or clay-based materials. The common pitfalls during specimen preparation, machine settings and interpretation of

  13. 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...

  14. Clay energetics in chemical evolution

    Science.gov (United States)

    Coyne, L. M.

    1986-01-01

    Clays have been implicated in the origin of terrestrial life since the 1950's. Originally they were considered agents which aid in selecting, concentrating and promoting oligomerization of the organic monomeric substituents of cellular life forms. However, more recently, it has been suggested that minerals, with particular emphasis on clays, may have played a yet more fundamental role. It has been suggested that clays are prototypic life forms in themselves and that they served as a template which directed the self-assembly of cellular life. If the clay-life theory is to have other than conceptual credibility, clays must be shown by experiment to execute the operations of cellular life, not only individually, but also in a sufficiently concerted manner as to produce some semblance of the functional attributes of living cells. Current studies are focussed on the ability of clays to absorb, store and transfer energy under plausible prebiotic conditions and to use this energy to drive chemistry of prebiotic relevance. Conclusions of the work are applicable to the role of clays either as substrates for organic chemistry, or in fueling their own life-mimetic processes.

  15. 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)

  16. 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.

  17. Clays in radioactive waste disposal

    OpenAIRE

    Delage, Pierre; CUI, Yu-Jun; Tang, Anh-Minh

    2010-01-01

    Clays and argillites are considered in some countries as possible host rocks for nuclear waste disposal at great depth. The use of compacted swelling clays as engineered barriers is also considered within the framework of the multi-barrier concept. In relation to these concepts, various research programs have been conducted to assess the thermo-hydro-mechanical properties of radioactive waste disposal at great depth. After introducing the concepts of waste isolation developed in Belgium, Fran...

  18. 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...

  19. Radiological characterization of pharmaceutical and cosmetic clays

    International Nuclear Information System (INIS)

    Natural radionuclide activity concentration (235U, 238U, 234U, 230Th, 226Ra, 232Th, 228Th, 228Ra and 40K) in clay materials used for cosmetic and medical purposes was determined by alpha and gamma spectrometry. The activity concentration resulted in the range of 0.71 and 4.42 Bq kg-1 for 235U, 15.1-91.4 and 15.3-81.6 Bq kg-1 for 238U and 234U, respectively, 18.7-72.4 Bq kg-1 for 230Th, 27.6-59.7 for 226Ra, 7.80-55.0 and 8.76-58.1 for 232Th and 228Th, 8.60-66.9 Bq kg-1 for 228Ra and 151.6-1,459 Bq kg-1 for 40K. In an oral treatment, the intake was calculated and for some radionuclides the results were higher than the annual dietary intake. (author)

  20. 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...

  1. Barrier properties of natural clay minerals

    OpenAIRE

    Дудар, Т.В.; С.П. Бугера; В.М. Кадошніков; Б.П. Злобенко

    2009-01-01

     Clay minerals is a perfect material for geochemical barrier due to their high water resistivity, plasticity, high sorbing capacity, well developed surface and cheapness in extraction and processing. This work studies the peculiarities of uranium sorbtion on clay minerals on the example of bentonite and palygorskite clay from Cherkassy deposit, and clay usage as a barrier material.

  2. Barrier properties of natural clay minerals

    Directory of Open Access Journals (Sweden)

    Т.В. Дудар

    2009-01-01

    Full Text Available  Clay minerals is a perfect material for geochemical barrier due to their high water resistivity, plasticity, high sorbing capacity, well developed surface and cheapness in extraction and processing. This work studies the peculiarities of uranium sorbtion on clay minerals on the example of bentonite and palygorskite clay from Cherkassy deposit, and clay usage as a barrier material.

  3. 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...

  4. SBR Brazilian organophilic/clay nanocomposites

    International Nuclear Information System (INIS)

    The aim of this work is the obtaining of SBR composites using a Brazilian raw bentonite and the same bentonite treated with an organic salt. The clays were characterized by XRD. The clay addition in the composites was 10 pcr. The composites were characterized by XRD and had measured theirs tension strength (TS). The composite with Brazilian treated clay showed TS 233% higher than a composite with no clay, 133% higher than a composite with Cloisite 30B organophilic clay and 17% lower than a composite with Cloisite 20 A organophilic clay. XRD and TS data evidence that the composite with Brazilian treated clay is an intercalated nanocomposite. (author)

  5. 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...

  6. Characterisation and engineering properties of Tiller clay

    OpenAIRE

    Gylland, A.; Long, Michael; Emdal, A.; et al.

    2013-01-01

    A detailed characterisation of the quick clay underlying the NTNU research site at Tiller, Trondheim is presented. The objective of the work is to provide guidance on quick clay parameters to engineers and researchers working with similar clays in Scandinavia and North America especially on landslide hazard assessment. The material is lightly overconsolidated and is characterised by its high degree of structure and very high sensitivity (quick clay). Clay and water contents are both about 40%...

  7. Thermal Behaviour of clay formations

    International Nuclear Information System (INIS)

    The programme carried out by ENEA to model the thermal-hydraulic-mechanical behaviour of the clay formations and to measure, in situ and in laboratory, the thermal properties of these rocks, is presented. An in situ heating experiment has been carried out in an open clay quarry in the area of Monterotondo, near Rome. The main goal of the experiment was to know the temperature field and the thermal effects caused by the high level radioactive waste disposed of in a clayey geological formation. The conclusions are as follows: - the thermal conduction codes are sufficiently accurate to forecast the temperature increases caused in the clay by the dissipation of the heat generated by high level radioactive waste; - the thermal conductivity deduced by means of the ''curve fitting'' method ranges from 0.015 to 0.017 W.cm-1.0C-1 - the temperature variation associated with the transport of clay interstitial water caused by temperature gradient is negligible. A laboratory automated method has been designed to measure the thermal conductivity and diffusivity in clay samples. A review of experimental data concerning thermomechanical effects in rocks as well as results of thermal experiments performed at ISMES on clays are presented. Negative thermal dilation has been found both in the elastic and plastic range under constant stress. Thermoplastic deformation appears ten times greater than the thermoelastic one. A mathematical model is proposed in order to simulate the above and other effects that encompass thermal-elastic-plastic-pore water pressure response of clays at high temperature and effective pressure with undrained and transient drainage conditions. Implementation of the two versions into a finite element computer code is described

  8. 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 ...

  9. 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)

  10. 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.

  11. 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

  12. Role of clay microstructure in expandable buffer clay

    Czech Academy of Sciences Publication Activity Database

    Pusch, R.; Přikryl, R.; Weishauptová, Zuzana; Xiaodong, L.; Knutsson, S.

    2012-01-01

    Roč. 1, č. 6 (2012), s. 267-292. ISSN 2232-1179 R&D Projects: GA ČR GA205/08/0676 Institutional research plan: CEZ:AV0Z30460519 Keywords : cementation * expandable clay * hydraulic conductivity Subject RIV: DL - Nuclear Waste, Radioactive Pollution ; Quality http://pure.ltu.se/portal/files/39920921/332.pdf

  13. Biodegradable Pectin/clay Aerogels

    Science.gov (United States)

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  14. 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...

  15. 21 CFR 186.1256 - Clay (kaolin).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Clay (kaolin). 186.1256 Section 186.1256 Food and... Substances Affirmed as GRAS § 186.1256 Clay (kaolin). (a) Clay (kaolin) Al2O3.2SiO2.nH2O, Cas Reg. No. 1332-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin)...

  16. Sorption of Cesium on Latvia clays

    International Nuclear Information System (INIS)

    Cesium is like potassium - good solubility and mobile in a ground, easy assimilates in organism expressly brawn woof. It is a problem if pollutant is radioactive 137Cs. We made experiments to sorption a 2M CsF solution on some Latvian clays which mainly contain hydro micas. We establish that clay treated with 25% sulfuric acid absorb cesium two times more that waste clay. Hereto unstuck elute Cs from clays

  17. GEOSYNTHETIC CLAY LINERS (GCLS) IN LANDFILL COVERS

    Science.gov (United States)

    Low permeability, compacted clay linters are commonly required as a barrier to water infiltration in landfill covers. elatively new material, known as geosynthetic clay liner (GCL), has been proposed as an alternative to a compacted clay liner. CL has the practical advantages of ...

  18. 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

  19. 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

  20. 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

  1. Clay-based Nanocomposites Possibilities and Limitations

    Science.gov (United States)

    Papoulis, Dimitris

    2011-09-01

    In the last decades, clay mineral based nanocomposites and polymer-clay nanocomposites (PCNC) have been proposed as very useful materials for many uses including photocatalysis, medicinal uses as tissue engineering or modified drug delivery systems. Clay minerals and especially montmorillonite, kaolinite, halloysite palygorskite and sepiolite are the most used clay minerals because of their high surface areas, colloidal dimensions of their particles and other properties. This lecture aims at reporting on very recent developments in the use of clay minerals and PCNC as materials with photocatalytic and medical interest.

  2. Preparation and characterization of bentonite organo clay

    International Nuclear Information System (INIS)

    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. Sorption of cesium on Latvian clays

    International Nuclear Information System (INIS)

    Cesium is like potassium - good solubility and mobile in a ground, easily assimilate in organism expressly brawn woof. It is a problem if pollutant is a radioactive 137Cs. We made experiments to sorption a 2M CsF solution on some Latvian clays which mainly contain hydro micas (cesium content after good elute of clays are in table). We establish, that clay treated with 25 % sulfuric acid adsorb cesium two times more that waste clay. Hereto unstuck elute Cs from clays. (author)

  4. The influence of filler concentration on the final properties of surlyn/clay nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Kovářová, L.; Měřínská, D.; Kalendová, A.; Šimoník, J.; Šlouf, Miroslav; Maláč, J.

    Halle-Wittenberg : Martin Luther University, 2005, SL12.17/1-SL12.17/8. ISBN 3-86010-784-4. [Annual Meeting of Polymer Processing Society /21./. Lepzig (DE), 19.06.2005-23.06.2005] Institutional research plan: CEZ:AV0Z40500505 Keywords : surlyn/clay nanocomposites * montmorillonite Subject RIV: CD - Macromolecular Chemistry

  5. Polyvinylchloride/clay nanocomposites based on the alkyl-amine intercalates with different length of chain

    Czech Academy of Sciences Publication Activity Database

    Kalendová, A.; Pospíšil, M.; Kovářová, L.; Měřínská, D.; Šimoník, J.; Čapková, P.; Valášková, M.; Vlková, Helena

    Akron : Polymer Processing Society , 2004. s. 248. [Polymer Processing Society Annual Meeting. 20.06.2004-24.06.2004, Akron] R&D Projects: GA AV ČR KSK4050111 Keywords : polyvinylchloride/clay * alkyl-amine intercalates * polymer nanotechnology Subject RIV: CD - Macromolecular Chemistry

  6. 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.

  7. 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

  8. Structural classification of clay soils and its application in classifying Tehran City clays

    International Nuclear Information System (INIS)

    The behaviour of all reconstituted and natural clays is determined by their fabric and bonding. A new classification of clays is proposed in this paper on the basis of standard penetration test (Spt), the geological history and the one-dimensional compression of the clay in the 1v-σv plane. Although the eighth clay types defined in the classification have different origins, fabric and bonding, they all have either a syn-sedimentation or a post-sedimentation structure. The definition of these clay types is taken as a starting point for the construction of a general framework of behaviour of clays. In this research results of laboratory and field investigations of a very stiff Tehran silty clay in the natural and reconstituted states including Spt, Odometer, Scanning Electron Microscopy and polarizing microscopy are presented. The structure of the Tehran silty clay is strongly influenced by bonding, calcium carbonate content and weathering intensity. This soil is a very stiff to hard clay which geologically is over-consolidated. Consolidation curve of soils lies close to the Icl line. Hence the Tehran silty clay is a type 4 clay but, at certain depths where the yield stress ratio is greater than 1, the Tehran silty clay becomes a type 7 clay

  9. From clay bricks to deep underground storage

    International Nuclear Information System (INIS)

    This booklet issued by the Swiss National Cooperative for the Disposal of Radioactive Waste NAGRA takes a look at the use of clay strata for the storage of radioactive wastes in deep-lying repositories. First of all, a geological foray is made concerning the history of the use of clay and its multifarious uses. The characteristics of clay and its composition are examined and its formation in the geological past is explained. In particular Opalinus clay is looked at and the structures to be found are discussed. The clay's various properties and industrial uses are examined and its sealing properties are examined. Also, Bentonite clay is mentioned and work done by Nagra and co-researchers is noted

  10. Measuring and Modeling the Plasticity of Clays

    Directory of Open Access Journals (Sweden)

    Fernando Augusto de Andrade

    2010-09-01

    Full Text Available The measurement of plasticity in clay bodies is crucial in order to get products free of defects and with less processing time. However, tests which simulate the behavior of the clay during processing and the mathematical modeling of some of its characteristics, particularly the plasticity, become difficult because many variables are involved and there is no consensus on the choice of method to be used. This study aimed to develop a mathematical model based on compression test to evaluate the plasticity of clays. Three types of clays were studied with different levels of moisture and their indices of plasticity were also characterized by the Atterberg's and Pfefferkorn's methods. The experimental data were well fitted by the theoretical curves for a wide range of clay plasticity. Moreover, it was possible to observe a correlation between effective stress of compression and paste moisture within each group of clay.

  11. Thermal stability of PMMA–clay hybrids

    Indian Academy of Sciences (India)

    Tanushree Choudhury; Nirendra M Misra

    2010-04-01

    Materials with small particle size are being extensively used in composites and hybrid materials. Exfoliated clay–polymer hybrids show enhanced properties. Exfoliation of clay platelets can be affected by selecting dispersing agents. In the present work, clay dispersed by natural dispersant (soap stone powder), cetyl trimethyl ammonium bromide (CTAB) dispersed clay and acid clay (amorphous clay) are taken. They are then polymerized with poly methyl methacrylate (PMMA) by solution intercalation method. The thermal stability of these different clay–PMMA hybrids have been studied and compared with that of pure PMMA by differential scanning calorimeter (DSC). The bonding of clay with PMMA has been studied by IR. Morphology of clay–PMMA hybrids has been shown by SEM and XRD which indicate partially exfoliated structure in T606-4 and intercalated structures in T606-6 and T606-2.

  12. Structural studies of pillared clays and modified pillared clays

    Energy Technology Data Exchange (ETDEWEB)

    Carrado, K.A.; Thompson, A.R.; Winans, R.E.; Botto, R.E.

    1987-11-01

    The long-range order of pillared interlayered clays (PILCs) after acid activation with 0.05N HCl has been investigated by X-ray diffraction (XRD) methods. The data show that long-range order in PILCs decreases as AlCH-PB = ZrCH-PB much greater than Zr/AlCH-PB = Cr/AlCH-PB (PB = pillared bentonite; MCH = metal chlorohydroxy pillaring agent, where M = Al, Zr or Cr). Apparently, pure oxide clusters are more stable than mixed oxide clusters. Treatment of PILCs with dilute HCl at 25/sup 0/C is less damaging than at reflux temperature, and calcined PILCs are more stable than air-dried materials. More structural damage occurs with 3M sulfuric acid treatment than with dilute HCl. Treatment with a weak base also causes some degradation of the pillars. /sup 27/Al-MAS NMR has been used to study pillared hectorite (PH), as well as other clay systems. The large increase of the observable octahedral aluminum (Al(VI)) resonance seen after pillaring is explained by loss of water from the (Al/sub 13/O/sub 4/(OH)/sub 24/(H/sub 2/O)/sub 12/)/sup 7 +/ (Al/sub 13/) cation. /sup 27/Al spectra of PILCs derived from different pillaring agents and exposed to various heat and acid treatments are remarkably similar. 16 refs., 1 fig., 1 tab.

  13. The plastic limit of clays

    OpenAIRE

    Haigh, Stuart K.; Vardanega, Paul J.; Bolton, Malcolm D.

    2013-01-01

    The plastic limit of soils was first described by Atterberg in 1911. The thread-rolling test was standardised at the US Public Roads Bureau in the 1920s and 1930s, and has subsequently become one of the standard tests of soil mechanics. This paper reviews the original definitions of plastic limit as proposed by Atterberg, and proposes that the brittle failure observed in the plastic limit test is caused by either air entry or cavitation in the clay. Critical state soil mechanics is used to sh...

  14. Radiological assessment of pharmaceutical clays

    International Nuclear Information System (INIS)

    The suitability for pharmaceutical and cosmetic application of fourteen clay samples, eight raw and six commercialized samples, from Minas Gerais and Sao Paulo states, Brazil, were evaluated and their mineralogy, chemical and radiological composition were determined. Results indicated that the samples are composed mainly of quartz, kaolinite and feldspar, enriched in Al2O3 and TiO2, Cd, Cs, Sb, Se, Th, and U and depleted in SiO2, MgO, P2O5, and Ca. Concentrations found are unlikely to present any harm in topical applications, and all the radiological parameters were below the global average or the established limits. (author)

  15. Retention processes in clay-rocks

    OpenAIRE

    Tournassat, Christophe; Grangeon, Sylvain

    2015-01-01

    International audience Within the context of the clay barrier concept for underground nuclear waste storage, montmorillonite and bentonite have been widely used as reference materials for radionuclides (RN) retention studies. Associated modeling work aims at understanding and predicting the retention of RN in clay-rocks where clay minerals are assumed to be representative of the most reactive phases. This " bottom-up " approach relies on a good confidence in the mechanistic understanding o...

  16. Ceramic clays from the western part of the Tamnava Tertiary Basin, Serbia: Deposits and clay types

    Directory of Open Access Journals (Sweden)

    Radosavljević Slobodan

    2014-01-01

    Full Text Available Based on geological, mineralogical, physical, chemical and technological investigations in the Tamnava Tertiary Basin near Šabac town (western Serbia, deposits of ceramic clays were studied. These ceramic clays are composed of kaolin-illite with a variable content of quartz, feldspars, mica, iron oxides and hydroxides, and organic matter. Four main types of commercial clays were identified: i red-yellow sandy-gravely (brick clays; ii grey-white poor sandy (ceramic clays; iii dark-carbonaceous (ceramic clays; and iv lamellar (“interspersed” fatty, poor sandy (highly aluminous and ferrous clays. Ceramic clays are defined as medium to high plastic with different ranges of sintering temperatures, which makes them suitable for the production of various kinds of materials in the ceramic industry. [Projekat Ministarstva nauke Republike Srbije, br. OI-176016

  17. 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)

  18. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Michael Rajamathi; Grace S Thomas; P Vishnu Kamath

    2001-10-01

    Together with hydrotalcite-like layered double hydroxides, bivalent and trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange properties together with surface basicity making them materials of importance for many modern applications. In this article, we discuss many different ways of making anionic clays and compare and contrast the rich diversity of this class of materials with the better-known cationic clays.

  19. Iodide uptake by negatively charged clay interlayers?

    Science.gov (United States)

    Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

    2015-09-01

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. PMID:26057987

  20. 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

  1. Geological explorations of clay deposit near Pragersko and clay quality tests

    OpenAIRE

    Duška Rokavec

    2002-01-01

    A series of illite clays located near Pragersko, at the southern boundary of the Maribor – Ptuj depression, was investigated. The results of mining geological investigations showed the extension and characteristics of clay occurrences in the area. Primary characteristics of single types of raw clay from the deposit (mineral composition, grain size distribution, plasticity, etc.), and the quality of biscuit were determined with laboratory tests.In a 4-9 m thick bed of clay we identified four d...

  2. Clay Minerals – Mineralogy and Phenomenon of Clay Swelling in Oil

    OpenAIRE

    Karpiński B.; Szkodo M.

    2015-01-01

    Among the minerals found in the earth's crust, clay minerals are of the widest interest. Due to the specific properties such as plasticity, absorbing and catalytic properties clay minerals are used in many industries (oil & gas, chemistry, pharmacy, refractory technology, ceramics etc.). In drilling, a phenomenon of swelling clays is frequently observed. It has an important impact on the cementing quality. During the last few decades clays have been the subject of research on a scale unpreced...

  3. Iodide uptake by negatively charged clay interlayers?

    International Nuclear Information System (INIS)

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. - Highlights: • Iodide sorption experiments were completed with a diverse array of clay minerals. • Iodide uptake trended with CEC and swamping electrolyte identity and concentration. • Results can be explained by considering the formation of ion pairs in clay interlayers

  4. Dehydration-induced luminescence in clay minerals

    Science.gov (United States)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  5. 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.

  6. Geomechanics of clays for radioactive waste disposal

    International Nuclear Information System (INIS)

    Clay formations have been studied for many years in the European Community as potential disposal media for radioactive waste. This document brings together results of on-going research about the geomechanical behaviour of natural clay bodies, at normal and elevated temperatures. The work is carried out within the third Community R and D programme on Management and storage of radioactive waste

  7. 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.

  8. Clays and other minerals in prebiotic processes

    Science.gov (United States)

    Paecht-Horowitz, M.

    1984-01-01

    Clays and other minerals have been investigated in context with prebiotic processes, mainly in polymerization of amino acids. It was found that peptides adsorbed on the clay, prior to polymerization, influence the reaction. The ratio between the amount of the peptides adsorbed and that of the clay is important for the yield as well as for the degrees of polymerization obtained. Adsorption prior to reaction produces a certain order in the aggregates of the clay particles which might induce better reaction results. Excess of added peptides disturbs this order and causes lesser degrees of polymerization. In addition to adsorption, clays are also able to occlude between their layers substances out of the environment, up to very high concentrations.

  9. Characterization of a few Mexican clays

    International Nuclear Information System (INIS)

    The characterization of a few Mexican clays with chemical treatment for possible application as catalysers is shown. The natural clays are treated with H2SO4, HF, F3 CSO3H, HClO4 and their behavior in reactions with some alcohols was recorded. The analysis were made before and after using the clays as catalysers. The clays were characterized by Moessbauer spectroscopy, X-ray diffraction, X-ray fluorescence analysis, and differential thermo analysis. The predominant mineral species are: montmorillonite, christobalite and quartz. The main elements are: Si, Al, Fe, Ca, K, etc. The Moessbauer results show mainly a paramagnetic doublet of Fe3+. The clays behave similarly as described in the literature. (author)

  10. 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...

  11. 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...

  12. THE EFFECT OF CLAY DISPERSION ON THE CRYSTALLIZATION AND MORPHOLOGY OF POLYPROPYLENE/CLAY COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Qin Zhang; Xiao-lin Gao; Ke Wang; Qiang Fu

    2004-01-01

    PP/clay composites with different dispersions, namely, exfoliated dispersion, intercalated dispersion and agglomerates and panicle-like dispersion, were prepared by direct melt intercalation or compounding. The effect of clay dispersion on the crystallization and morphology of PP was investigated via PLM, SAXS and DSC. Experimental results show that exfoliated clay layers are much more efficient than intercalated clay and agglomerates of clay in serving as nucleation agent due to the nano-scale dispersion of clay, resulting in a dramatic decrease in crystal size (lamellar thickness and spherulites) and an increase of crystallization temperature and crystallization rate. On the other hand, a decrease of melting temperature and crystallinity was also observed in PP/clay composites with exfoliated dispersion, due to the strong interaction between PP and clay. Compared with exfoliated clay layers, the intercalated clay layers have a less important effect on the crystallization and crystal morphology. No effect is seen for samples with agglomerates and panicle-like dispersion, in regard to melting temperature, crystallization temperature, crystal thickness and crystallinity.

  13. Discrete analysis of clay layer tensile strength

    International Nuclear Information System (INIS)

    The Discrete Element Method is used to investigate the tensile behaviour and cracks mechanisms of a clay material submitted to bending loading. It is the case of compacted clay liners in landfill cap cover application. Such as the soil tested in this study is plastic clay, the distinct elements model was calibrated with previous data results by taking into account cohesive properties. Various contact and cohesion laws are tested to show that the numerical model is able to reproduce the failure mechanism. Numerical results are extending to simulate a landfill cap cover and comparing to experimental large scale field bending tests achieved in a real site of storage. (authors)

  14. Radionuclides sorption in clay soils

    International Nuclear Information System (INIS)

    The sorption behaviour of clay soils is examined through a parametric study of the distribution coefficient (Kd) for the radionuclides of interest, Cs and Sr. This work is a preliminary stage of the migration studies of these nuclides in a porous medium (ground of Ezeiza, Argentina) and the evaluation of radiologic impact of the removal of low and intermediate activity wastes in shallow trenches. The determination of Kd is performed by a static technique or batch. The phases are separated by centrifugation at 20000 g during 1 hour. The activity of supernatant solution of Cs-137 and Sr-85 is measured in a detecting system of I Na(Tl) well-type. Two types of parameters were changed: a) those related to the determination method: phase separation (centrifugation vs. centrifugation plus filtration); equilibrium period, ratio solid/liquid; b) those related to the geochemical system: pH of contact solution, carrier concentration, competitive ions, ionic strength, desorption. It was observed that the modification of parameters in the Kd-measurement does not change the order of magnitude of results. (Author)

  15. Clay Dispersibility and Soil Friability - Testing the Soil Clay-to-Carbon Saturation Concept

    DEFF Research Database (Denmark)

    Schjønning, Per; de Jonge, Lis Wollesen; Munkholm, Lars Juhl;

    2012-01-01

    either air-dried or rewetted to −100 hPa matric potential. Tensile strength of 1- to 2-, 2- to 4-, 4- to 8-, and 8- to 16-mm air-dried aggregates was calculated from their compressive strength, and soil friability estimated from the strength–volume relation. Crop rotation characteristics gave only minor......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 3 yr in a field varying in clay content (∼100 to ∼220 g kg−1 soil) and grown with different crop rotations. Clay dispersibility was measured after end-over-end shaking of field-moist soil and 1- to 2-mm sized aggregates...

  16. Clay Minerals – Mineralogy and Phenomenon of Clay Swelling in Oil

    Directory of Open Access Journals (Sweden)

    Karpiński B.

    2015-03-01

    Full Text Available Among the minerals found in the earth's crust, clay minerals are of the widest interest. Due to the specific properties such as plasticity, absorbing and catalytic properties clay minerals are used in many industries (oil & gas, chemistry, pharmacy, refractory technology, ceramics etc.. In drilling, a phenomenon of swelling clays is frequently observed. It has an important impact on the cementing quality. During the last few decades clays have been the subject of research on a scale unprecedented in the history of mineralogy. This paper presents review literature on mineralogy of clay minerals and phenomenon of swelling in oil and gas industry. Unique ion exchange properties and clay swelling mechanisms are also considered.

  17. Study of radionuclide migration in clay formations

    International Nuclear Information System (INIS)

    This paper reports the studies on the migration of Cs, Sr and I in clay formations, which are presently considered for the geological disposal of radioactive wastes. The distribution and diffusion coefficients were evaluated by means of experimental techniques and computer procedures, which are presented in this report. The natural clays tested in the laboratory experiments were sampled from the most representative italian basins and from the zone of Mol (Belgium). In addition tests were performed on monomineral clays artificially remade in edometer. The experimental results are in accordance with data found in the literature and show the existence of a good correlation between the observed migration properties and the granulometric and mineralogic characteristics of the natural clays

  18. Moessbauer firing study of Lishan clay

    International Nuclear Information System (INIS)

    Lishan clay has been characterized by Moessbauer spectroscopy, X-ray diffraction, X-ray fluorescence, neutron activation, thermal and chemical analysis. It is proved that Lishan clay is the material used for making the terra-cotta warriors and horses of Qin Dynasty. Firing testing of clay was carried out in various conditions. The transformations induced by firing of clay were characterized by Moessbauer spectra. The data on quadrupole splittings of Fe3+ or Fe2+ ions, and on nonmagnetic component distributions at different firing temperatures, may lead to valuable informations on the manufacture of ancient pottery. The sintering temperature for the treea-cotta warriors and horses of Qin Dynasty was thus evaluated to be 950-1030 deg C

  19. Interaction of Auramine O with montmorillonite clays

    International Nuclear Information System (INIS)

    The spectroscopic behaviour of Auramine O (AuO) in aqueous suspensions of montmorillonite clays was studied using absorption and static and dynamic fluorescence techniques. The fluorescence of Auramine O increases immediately after mixing the dye solution with the suspension of clay due to its adsorption on the external surface of the clays, which restricts the torsional molecular motion of Auramine. At longer times, the dye molecules migrate into the interlamellar region of the clay particles. Aggregation of the dye molecules can occur in the interlayer region, leading to the decrease of the fluorescence emission. The fluorescence quantum yields (ΦF) of AuO on the natural montmorillonites SAz-1, SWy-1, Syn-1 and Laponite clays were 0.015, 0.007, 0.016 and 0.017, respectively. These values are higher than the ΦF of AuO in aqueous solution and are of the same order of magnitude of the ΦF found for viscous solvents such as n-hexanol and n-heptanol (0.014 and 0.015). Time-resolved fluorescence spectroscopy studies of adsorbed Auramine on clays revealed multi-exponential decays with components in the 25–36, 219–362 and 1300–1858 ps ranges. The short-lived components can be attributed to species bound to external surface and the longer lifetime is assigned to dye molecules in interlayer spaces interacting strongly with the clay. It seems clear that the binding of Auramine to clays causes a significant reduction of the rate of internal conversion that does involve rotational diffusion, so that the clay will be locked in a conformational geometry unfavourable for internal conversion. -- Highlights: ► Auramine O was dissolved in dispersions of different clays. ► The fluorescence quantum yields were higher than in aqueous solution. ► Decrease of the emission and triexponential decays were observed on SAz-1, LapRDS and SYn-1. ► On Swy-1 the decrease was slower and the decay monoexponential. ► The dye produces aggregates on the internal lamellar region of

  20. Aspects of clay/concrete interactions

    International Nuclear Information System (INIS)

    In the Canadian concept for nuclear fuel waste management, both clay-based materials and concrete are proposed for use as barriers, seals or supporting structures. The main concern when clays and concrete are in proximity is the generation of a high-pH environment by concrete since clay minerals are relatively unstable at high pH. Here we examine the OH--generating capacity of two high-performance concretes when in contact with several solutions. We also investigate various aspects of claylconcrete interactions. They are: (1) the alkalimetric titration of clay suspensions, (2) the effect of Ca(OH)2 (portlandite) on the swelling and hydraulic properties of compacted bentonite, and (3) the influence of cement grout on a backfill clay retrieved from the 900-d Buffer/Container Experiment at the Underground Research Laboratory of AECL. The results indicate that although high-performance concretes establish significantly lower poresolution pH (9 to 10) than does ordinary portland cement, the pH is still somewhat higher than that of clay/groundwater systems of about pH 8. Hence, even if high-performance concrete is used in a disposal vault, the potential still exists for clay minerals to alter over long periods of time if in contact with this concrete. The data show, however, that clays have a substantial buffering capacity, and clay-based barriers can thus neutralize much of the OH- potentially released from concrete in a vault. Moreover, even after reacting for 120 d at 85oC with up to 5 wt.% Ca(OH)2, compacted bentonite (dry density = 1.2 Mg/m3 ) retains much of its swelling capacity and has a permeability low enough (hydraulic conductivity ≤ 10-11 m/s) to ensure that molecular diffusion will be the main transport mechanism through compacted clay-based barriers. Furthermore, according to X-ray diffractometry, the clay mineral component of backfill was not altered by contact with a cement grout for 900 d in the Buffer/Container Experiment

  1. Surface geochemistry of the clay minerals

    OpenAIRE

    Sposito, Garrison; Skipper, Neal T.; Sutton, Rebecca; Park, Sung-Ho; Soper, Alan K.; Greathouse, Jeffery A.

    1999-01-01

    Clay minerals are layer type aluminosilicates that figure in terrestrial biogeochemical cycles, in the buffering capacity of the oceans, and in the containment of toxic waste materials. They are also used as lubricants in petroleum extraction and as industrial catalysts for the synthesis of many organic compounds. These applications derive fundamentally from the colloidal size and permanent structural charge of clay mineral particles, which endow them with significant ...

  2. Nanomechanical characterization of clay micro flocs

    OpenAIRE

    Zhang, Guoping; Yin, Hang; Reed, Allen

    2014-01-01

    Clay flocs are abundant in natural soils (a particulate material) and water-borne sediments. As the basic microscale, loading-bearing fundamental units, their mechanical properties control the macroscopic response of bulk soils and sediment transport. Owing to their tiny size and extremely soft consistency (especially for suspended water-borne flocs), significant difficulties and challenges exist for mechanical characterization of clay micro flocs. A novel nanomechanical characterization tech...

  3. Dynamic properties of composite cemented clay

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 梁旭

    2004-01-01

    In this work,the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays.

  4. Effects of subsurface cavity expansion in clays

    OpenAIRE

    Au, SKA; Yeung, AT; Soga, K; Cheng, YM

    2007-01-01

    Subsurface cavity expansion in clay induced by compaction grouting can generate upward displacement of clay and/or increase in effective stress leading to consolidation, resulting in settlement compensation and/or shear strength enhancement respectively. However, the two potential benefits of subsurface cavity expansion may offset each other. Experiments and numerical simulations on the engineering behaviour of E-grade kaolin induced by subsurface pressure-controlled cavity expansion were con...

  5. The aeration of clay soils in cricket

    OpenAIRE

    Parsons, Simon A.

    2012-01-01

    In the game of cricket good ball-surface interactions are essential and require a hard, flat surface. To achieve this the clay loam soil comprising the pitch is compressed and compacted using a smooth wheeled roller, which when combined with the drying action of the grass plant roots, causing the clay minerals within the soil to shrink, creates a high bulk density, hard surface on which to play. High bulk density soils present difficult growing conditions for plants due to h...

  6. 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.

  7. Water vapour permeability of clay bricks

    OpenAIRE

    Dondi, M.; Principi, P.; Raimondo, M.; Zanarini, G.

    2003-01-01

    The water vapour permeability of clay bricks has been experimentally measured in order to draw a representative outline of industrial products without pore-forming additives. The correlations between water vapour permeability and the main compositional and microstructural parameters of both bricks and clay bodies have been investigated. A statistical model was set up in order to predict with reasonable precision and reliability, the water vapour permeability on the basis of open porosity, bul...

  8. Measuring and Modeling the Plasticity of Clays

    OpenAIRE

    Fernando Augusto de Andrade; Hazim Ali Al-Qureshi; Dachamir Hotza

    2010-01-01

    The measurement of plasticity in clay bodies is crucial in order to get products free of defects and with less processing time. However, tests which simulate the behavior of the clay during processing and the mathematical modeling of some of its characteristics, particularly the plasticity, become difficult because many variables are involved and there is no consensus on the choice of method to be used. This study aimed to develop a mathematical model based on compression test to evaluate the...

  9. 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...

  10. Distribution And Mineralogy Of The Clay Deposits In Saudi Arabia

    OpenAIRE

    Al Mohandis, Ahmed A. [احمد عبد القادر المهندس

    1993-01-01

    The main goal of this paper is to characterize the mineral clay deposits in Saudi Arabia; especially their mineral composition, deposit size, geological setting and possible uses. Different published reports and papers on clay deposits of Saudi Arabia have been reviewed. Three major clay deposits have been studied by XRD, DTA and chemical analyses. Saudi clay deposits consist generally of kaolinite as a major mineral, and small amounts other clay minerals, such as montmorillonite and illite. ...

  11. 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...

  12. The constitution, evaluation and ceramic properties of ball clays

    OpenAIRE

    Wilson Ian Richard

    1998-01-01

    Ball clay is a fine-grained highly plastic, mainly kaolinitic, sedimentary clay, the higher grades of which fire to a white or near white colour. The paper will review the origin of the term "Ball Clay" and the location and origins of several deposits with particular emphasis on the mineralogical, physical and rheological properties which make the clays so important in ceramics bodies. Particular attention will be paid to the well known bay clay deposits of Devon and Dorset in southwest Engla...

  13. A clay grouting technique for granitic rock adjacent to clay bulkhead

    Science.gov (United States)

    Masumoto, K.; Sugita, Y.; Fujita, T.; Martino, J. B.; Kozak, E. T.; Dixon, D. A.

    Excavation and re-distribution of the stress around the tunnel lead to the development of an excavation damage zone (EDZ). While the bulkheads are keyed into the rock wall of the tunnel to act as cut-offs for the EDZ of the tunnel, clay grouting was conducted around the clay bulkhead as an additional measure to interrupt the connectivity of EDZ at the bulkhead. Clay grouting is being tested to determine if it is an effective method to reduce the permeability of fractured rock. The grouting into the EDZ is difficult because many of the fractures in the EDZ are connected with the excavation surface and cannot be filled efficiently by pressurizing the grout slurry. Therefore, the in situ injection tests of the clay grouting technique for the EDZ adjacent to the clay bulkhead were conducted to demonstrate the clay grouting technique and to estimate the ability of clay grouting to reduce permeability in the EDZ. This paper presents the results of these tests. Three in situ tests of clay grouting were performed during the Tunnel Sealing Experiment (TSX), conducted at Canada’s Underground Research Laboratory (URL) in the granitic rock to demonstrate technologies for tunnel sealing at full-scale. First, a clay grouting trial was conducted at a trial key in the tunnel about 25 m above the TSX tunnel. Secondly, the two series of clay grouting were performed in the TSX tunnel, on the upstream face of the key prior to the installation of the seal material of the clay key and later on the downstream side of the bulkhead. The results of these tests indicated a reduction in the permeability of granitic rock around the holes after grouting.

  14. NMR imaging and cryoporometry of swelling clays

    Science.gov (United States)

    Dvinskikh, Sergey V.; Szutkowski, Kosma; Petrov, Oleg V.; Furó, István.

    2010-05-01

    Compacted bentonite clay is currently attracting attention as a promising "self-sealing" buffer material to build in-ground barriers for the encapsulation of radioactive waste. It is expected to fill up the space between waste canister and surrounding ground by swelling and thus delay flow and migration from the host rock to the canister. In environmental sciences, evaluation and understanding of the swelling properties of pre-compacted clay are of uttermost importance for designing such buffers. Major goal of present study was to provide, in a non-invasive manner, a quantitative measure of bentonite distribution in extended samples during different physical processes in an aqueous environment such as swelling, dissolution, and sedimentation on the time scale from minutes to years. The propagation of the swelling front during clay expansion depending on the geometry of the confining space was also studied. Magnetic resonance imaging and nuclear magnetic resonance spectroscopy were adapted and used as main experimental techniques. With this approach, spatially resolved movement of the clay/water interface as well as clay particle distributions in gel phase can be monitored [1]. Bulk samples with swelling in a vertical tube and in a horizontal channel were investigated and clay content distribution profiles in the concentration range over five orders of magnitude and with sub-millimetre spatial resolution were obtained. Expansion rates for bulk swelling and swelling in narrow slits were compared. For sodium-exchanged montmorillonite in contact with de-ionised water, we observed a remarkable acceleration of expansion as compared to that obtained in the bulk. To characterize the porosity of the clay a cryoporometric study [2] has been performed. Our results have important implications to waste repository designs and for the assessment of its long-term performance. Further research exploring clay-water interaction over a wide variety of clay composition and water ionic

  15. Clay mineralogy of weathering rinds and possible implications concerning the sources of clay minerals in soils.

    Science.gov (United States)

    Colman, Steven M.

    1982-01-01

    Weathering rinds on volcanic clasts in Quaternary deposits in the western US contain only very fine-grained and poorly crystalline clay minerals. Rinds were sampled from soils containing well-developed argillic B horizons in deposits approx 105 yr old or more. The clay-size fraction of the rinds is dominated by allophane and iron hydroxy-oxides, whereas the B horizons contain abundant well-crystallized clay minerals. The contrast between the clay mineralogy of the weathering rinds, in which weathering is isolated from other soil processes, and that of the associated soil matrices suggests a need to reassess assumptions concerning the rates at which clay minerals form and the sources of clay minerals in argillic B horizons. It seems that crystalline clay minerals form more slowly in weathering rinds than is generally assumed for soil environments and that the weathering of primary minerals may not be the dominant source of crystalline clay minerals in Middle to Late Pleistocene soil.-A.P.

  16. Organic or organometallic template mediated clay synthesis

    Science.gov (United States)

    Gregar, Kathleen C.; Winans, Randall E.; Botto, Robert E.

    1994-01-01

    A method for incorporating diverse Varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  17. 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.

  18. The corrosion of copper in compacted clay

    International Nuclear Information System (INIS)

    The uniform corrosion behaviour of copper has been investigated in the presence of compacted clay under simulated disposal vault conditions. The compacted clay is used to simulate the buffer material that would surround copper nuclear fuel waste containers in a Canadian disposal vault. The effect of the speciation of dissolved Cu has been investigated using three synthetic groundwaters of different salinity and various dissolved [O2]. The formation of cuprous species is favoured by low [O2] and high [C1-], with Cu(II) species formed at high [O2] and low [C1-]. Because the Na-bentonite clay is a cation-exchange material, positively charged Cu(II) species are found to adsorb more strongly than negatively charged CuC1- complexes. The impact of the Cu speciation on four experimental parameters is reported: the corrosion rate, the interfacial [Cu] in the clay, the [Cu] profile through the clay layer, and the Cu(l):Cu(ll) ratio in the precipitated corrosion products. In agreement with previous studies, the overall rate-controlling process is believed to be the diffusion of dissolved Cu away from the corroding surface. Adsorption acts as a driving force for corrosion by immobilizing dissolved Cu. Under the conditions used in these experiments, the diffusion of dissolved O2 to the Cu surface was not rate controlling. (author)

  19. Organic or organometallic template mediated clay synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gregar, K.C.; Winans, R.E.; Botto, R.E.

    1992-12-31

    A method is given for incorporating diverse varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and LiF for 2 days with an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by US patent No. 3,887,454 issued to Hickson, June 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have water-solubility, positive charge, and thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  20. 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.

  1. One-Dimensional Simulation of Clay Drying

    Directory of Open Access Journals (Sweden)

    Siljan Siljan

    2002-04-01

    Full Text Available Drying of clay is simulated by a one-dimensional model. The background of the work is to form a better basis for investigation of the drying process in production of clay-based building materials. A model of one-dimensional heat and mass transfer in porous material is used and modified to simulate drying of clay particles. The convective terms are discretized by first-order upwinding, and the diffusive terms are discretized by central differencing. DASSL was used to solve the set of algebraic and differential equations. The different simulations show the effect of permeability, initial moisture content and different boundary conditions. Both drying of a flat plate and a spherical particle are modelled.

  2. Clay mineral variations near Pennsylvanian sandstone channels

    International Nuclear Information System (INIS)

    Large linear sandstone bodies in the Illinois Basin have been interpreted as representing fresh water river channels that flowed through generally marine to brackish Pennsylvanian deltaic environments; fresh water from such channels could have affected deposition of adjacent coal-bearing rocks. Low-sulfur coals are commonly associated with the sandstone bodies, which may also host petroleum, uranium, fresh water, or other resources. Thus techniques to locate such channels would be economically useful. Previous studies have shown that clay mineral distributions and bulk chemistries of clay-rich sediments are affected when fresh waters mix with sea water. Such changes associated laterally with freshwater channels might have caused distinctive clay mineral or chemical patterns to develop around the channels. Mineralogies and chemical compositions of more than 500 mudrock samples taken immediately above the springfield Coal Member of the Petersburg Formation from 52 sections located from channel margins to 63 miles distant were determined to discern patterns that could aid in finding channels

  3. Synthesis and characterization of waterborne polyurethane/organic clay nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Zai-feng LI; Sheng-jun WANG; Jin-yan LI

    2008-01-01

    Stable waterborne polyurethane/organic clay latex was synthesized by ultrasonically-assisted mixing with different clay content. Fourier transform infrared (FT-IR) spectra showed that the interaction between NH and C=O was enhanced with low content organic clay loaded. X-ray diffraction (XRD) results implied that the layered organic clay was exfoliated and the crystallization of the hard domain in the waterborne polyurethane (WPU) matrix was enhanced. Transmission electron microscopy (TEM) images show that the layered clay was exfoliated by WPU molecule. The tensile test shows that the mechanical prop-erties were improved by loading organic clay and the desired addition was 1 wt.%.

  4. 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

  5. Ostwald ripening of clays and metamorphic minerals

    Science.gov (United States)

    Eberl, D.D.; Srodon, J.; Kralik, M.; Taylor, B.E.; Peterman, Z.E.

    1990-01-01

    Analyses of particle size distributions indicate that clay minerals and other diagenetic and metamorphic minerals commonly undergo recrystallization by Ostwald ripening. The shapes of their particle size distributions can yield the rate law for this process. One consequence of Ostwald ripening is that a record of the recrystallization process is preserved in the various particle sizes. Therefore, one can determine the detailed geologic history of clays and other recrystallized minerals by separating, from a single sample, the various particle sizes for independent chemical, structural, and isotopic analyses.

  6. Thermal properties of clays and shales

    International Nuclear Information System (INIS)

    This report contains a compilation of much of the data needed for evaluating the thermal properties of clays and shales. The data on shales are limited so much of the review is concerned with clays and ceramic products. The information presented should allow a preliminary evaluation of the problems that will arise when canisters containing high-activity wastes are buried in shales. A computer library search was conducted and most of the data specific to the thermal properties of shales was probably found. Much more data are available on density, porosity, ceramic properties, diagenesis, etc., but the main points have been summarized

  7. Ostwald ripening of clays and metamorphic minerals.

    Science.gov (United States)

    Eberl, D D; Sacuterodonacute, J; Kralik, M; Taylor, B E; Peterman, Z E

    1990-04-27

    Analyses of particle size distributions indicate that clay minerals and other diagenetic and metamorphic minerals commonly undergo recrystallization by Ostwald ripening. The shapes of their particle size distributions can yield the rate law for this process. One consequence of Ostwald ripening is that a record of the recrystallization process is preserved in the various particle sizes. Therefore, one can determine the detailed geologic history of clays and other recrystallized minerals by separating, from a single sample, the various particle sizes for independent chemical, structural, and isotopic analyses. PMID:17815598

  8. Quick clay and landslides of clayey soils.

    Science.gov (United States)

    Khaldoun, Asmae; Moller, Peder; Fall, Abdoulaye; Wegdam, Gerard; De Leeuw, Bert; Méheust, Yves; Otto Fossum, Jon; Bonn, Daniel

    2009-10-30

    We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay soils. Reproducing landslides on a small scale in the laboratory shows that an additional factor that determines the violence of the slides is the inhomogeneity of the flow. We propose a simple yield stress model capable of reproducing the laboratory landslide data, allowing us to relate landslides to the measured rheology. PMID:19905837

  9. Clay as a barrier to radionuclide migration

    International Nuclear Information System (INIS)

    Because of their low permeability, high sorption capacity and plasticity clay bodies are potentially suitable repositories for radioactive waste. This paper discusses the factors that influence radionuclide mobility in natural clay materials. Methods for determining radionuclide migration rates are described and compared. Data requirements necessary to establish whether or not a particular site is suitable for waste disposal are discussed. Suggestions are made as to the most important generic research that needs to be carried out. In the appendix, some of the most relevant published sorption and diffusion data are summarized and compared. (author)

  10. Clay intercalation and influence on crystallinity of EVA-based clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, D.S. [Rheology and Materials Processing Centre, School of Civil and Chemical Engineering, RMIT University, 124 La Trobe St., Melbourne 3000 (Australia)]. E-mail: deeptangshu@hotmail.com; Prasad, R. [Rheology and Materials Processing Centre, School of Civil and Chemical Engineering, RMIT University, 124 La Trobe St., Melbourne 3000 (Australia); Gupta, R.K. [Rheology and Materials Processing Centre, School of Civil and Chemical Engineering, RMIT University, 124 La Trobe St., Melbourne 3000 (Australia); Bhattacharya, S.N. [Rheology and Materials Processing Centre, School of Civil and Chemical Engineering, RMIT University, 124 La Trobe St., Melbourne 3000 (Australia)]. E-mail: sati.bhattacharya@rmit.edu.au

    2005-08-01

    Various polymer clay nanocomposites (PCNs) were prepared from ethylene vinyl acetate copolymer (EVA) with 9, 18 and 28% vinyl acetate (VA) content filled with different wt.% (2.5, 5 and 7.5) of a Montmorillonite-based organo-modified clay (Cloisite[reg] C15A and C30B). The PCNs were prepared using melt blending techniques. Morphological information regarding intercalation and exfoliation were determined by using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). WAXS and TEM confirmed that increasing the VA content was necessary to achieve greater clay-polymer interaction as seen from the comparatively higher intercalation of clay platelets with 28% VA. The effect of addition of clay on the development and the modification of crystalline morphology in EVA matrix was also studied using WAXS and temperature-modulated differential scanning calorimetry (MDSC). Results are presented showing that the addition of clay platelets does not increase the matrix crystallinity but the morphology was significantly modified such that there was an increase in the 'rigid' amorphous phase. Mechanical properties were also evaluated against the respective morphological information for each specimen and there are indications that the level of clay-polymer interaction plays a significant role in such morphological modification, and in such a way that affects the final PCN mechanical properties which has wide and significant applications in the packaging industries.

  11. Clay intercalation and influence on crystallinity of EVA-based clay nanocomposites

    International Nuclear Information System (INIS)

    Various polymer clay nanocomposites (PCNs) were prepared from ethylene vinyl acetate copolymer (EVA) with 9, 18 and 28% vinyl acetate (VA) content filled with different wt.% (2.5, 5 and 7.5) of a Montmorillonite-based organo-modified clay (Cloisite[reg] C15A and C30B). The PCNs were prepared using melt blending techniques. Morphological information regarding intercalation and exfoliation were determined by using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). WAXS and TEM confirmed that increasing the VA content was necessary to achieve greater clay-polymer interaction as seen from the comparatively higher intercalation of clay platelets with 28% VA. The effect of addition of clay on the development and the modification of crystalline morphology in EVA matrix was also studied using WAXS and temperature-modulated differential scanning calorimetry (MDSC). Results are presented showing that the addition of clay platelets does not increase the matrix crystallinity but the morphology was significantly modified such that there was an increase in the 'rigid' amorphous phase. Mechanical properties were also evaluated against the respective morphological information for each specimen and there are indications that the level of clay-polymer interaction plays a significant role in such morphological modification, and in such a way that affects the final PCN mechanical properties which has wide and significant applications in the packaging industries

  12. Annual report 2009. Institute of Radiochemistry

    International Nuclear Information System (INIS)

    The annual report 2009 of the institute of radiochemistry covers the following topics: Part 1: Actinides (metals) in biosystems; Part 2: Actinides in waste repositories. The research projects were aimed to the basic knowledge about coordination of actinide element transport and transfer in the environment, bacteria influence on the immobilization of heavy metals in water and soils, microbial diversity in biofilms and clays, protein applications for biosensors, dominating processes of soil-liquid interfaces, sorption and surface complexation processes.

  13. Crystallite size distribution of clay minerals from selected Serbian clay deposits

    Directory of Open Access Journals (Sweden)

    Simić Vladimir

    2006-01-01

    Full Text Available The BWA (Bertaut-Warren-Averbach technique for the measurement of the mean crystallite thickness and thickness distributions of phyllosilicates was applied to a set of kaolin and bentonite minerals. Six samples of kaolinitic clays, one sample of halloysite, and five bentonite samples from selected Serbian deposits were analyzed. These clays are of sedimentary volcano-sedimentary (diagenetic, and hydrothermal origin. Two different types of shape of thickness distribution were found - lognormal, typical for bentonite and halloysite, and polymodal, typical for kaolinite. The mean crystallite thickness (T BWA seams to be influenced by the genetic type of the clay sample.

  14. Preparation of nanocomposites polyurethane water bone with clay montmorillonite sodica and organophilic clay

    International Nuclear Information System (INIS)

    Nanocomposites based on water bone polyurethane (NWPU's) were synthesized based on poli(propylene glycol), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and hydrazine (HYD), as chain extender. Two kinds of clays were employed: hydrophilic and organophilic. The nanocomposites were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electronic microscopy (SEM) and the mechanical properties were evaluated. The FTIR results showed the presence of specific groups of clay and the XRD suggested that occurred their intercalation/exfoliation through polyurethane matrix. The mechanical resistance of the systems showed significant increase when compared to water dispersions synthesized without clay. (author)

  15. Approach for decontamination from the viewpoint of clays and clay minerals

    International Nuclear Information System (INIS)

    It is essential to make the effective decontamination and to reduce the amount of the contaminated materials with radionuclides in the areas damaged from the Fukushima Daiichi nuclear disaster. The Clay Science Society of Japan (CSSJ) has made the great efforts for so-called 'Fukushima Problems' as one of the scientific groups for clay and clay minerals. A review is given of the contributions against the problem from CSSJ itself and also the interested members in CSSJ joining the interested research projects. We would like to realize again the important role of CSSJ for the problems considering the results in these projects. (author)

  16. Black Carbon, The Pyrogenic Clay Mineral?

    Science.gov (United States)

    Most soils contain significant amounts of black carbon, much of which is present as discrete particles admixed with the coarse clay fraction (0.2–2.0 µm e.s.d.) and can be physically separated from the more abundant diffuse biogenic humic materials. Recent evidence has shown that naturally occurring...

  17. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  18. 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...

  19. 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.

  20. 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.

  1. 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.)

  2. 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.)

  3. Clay Aerogel Supported Palladium Nanoparticles as Catalysts

    Directory of Open Access Journals (Sweden)

    Jared J. Griebel

    2016-04-01

    Full Text Available Highly porous, low density palladium nanoparticle/clay aerogel materials have been produced and demonstrated to possess significant catalytic activity for olefin hydrogenation and isomerization reactions at low/ambient pressures. This technology opens up a new route for the production of catalytic materials.

  4. Swelling transition of a clay induced by heating.

    Science.gov (United States)

    Hansen, E L; Hemmen, H; Fonseca, D M; Coutant, C; Knudsen, K D; Plivelic, T S; Bonn, D; Fossum, J O

    2012-01-01

    Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, 'active' clays that have the capacity for taking up large amounts of water to form stable gels, and 'passive' or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling. PMID:22943004

  5. Deformation mechanisms in experimentally deformed Boom Clay

    Science.gov (United States)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

    Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures

  6. Traditional Underground Grain Storage in Clay Soils in Sudan Improved by Recent Innovations

    Directory of Open Access Journals (Sweden)

    Abdalla, AT.

    2002-01-01

    Full Text Available In the central clay plain of the Sudan, traditional subsistence farmers and small farmers that also produce for local markets want to keep the region near food self-sufficiency. They combine annual production of sorghum with underground pit storage of part of the harvest. With increasing climate variability this food security is coming more and more under pressure. Farmers recently experimented with pit innovations that would allow storage for more than one season. These innovations were quantified and further improvements were suggested. It was found that in the most abundantly occurring cracking clay soils, wide shallow pits, using thick chaff linings, with wider above ground soil caps, are most suitable for longer term storage.

  7. Natural radioactivity and gamma dose from Sri Lankan clay bricks used in building construction

    International Nuclear Information System (INIS)

    The specific radioactivity concentrations of 226Ra, 232Th and 40K have been determined by gamma ray spectrometry with an HPGe detector in clay brick samples from kiln sites located in 17 towns. The average values of the measured activities are 35, 72, and 585 Bq kg-1, respectively, for the above radionuclides. The average estimated radium equivalent concentration is 183 Bq kg-1 and is comparable with reported values for many countries in the world. This value and the value obtained from the criteria formula suggest that the use of local clay bricks do not pose a radiological hazard. The calculated average absorbed dose rate in air within buildings was found to be 102 nGy h-1 while the population weighted indoor annual effective dose was 0.20 mSv

  8. Impact of microstructure on anion exclusion in compacted clay media

    OpenAIRE

    Tournassat, Christophe; Gaboreau, Stéphane; Robinet, Jean-Charles; Bourg, Ian C.; Steefel, Carl I

    2015-01-01

    International audience The sensitivity of ion concentration distribution models to three key model assumptions, the pore-size distribution of clay media, the distance of closest approach of ions to the clay surface, and the accessibility of sub-nanometer-wide clay mineral interlayer spaces to anions, was explored by solving the Poisson-Boltzmann equation for swelling and non-swelling clay materials. Our calculations show that all three model assumptions significantly impact values predicte...

  9. 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...

  10. 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...

  11. Production of smectite organophylic clays from three commercial sodium bentonite

    International Nuclear Information System (INIS)

    Laboratory cationic exchange procedures using Brazilian's commercial quaternary ammonium salt and three samples of commercial sodium bentonites (two Brazilian's and one from Wyoming (US) are described. Swelling values in some liquid organic media are shown for the organophilic clays and for a Brazilian's commercial organophilic clay. Organophilic clays with larger swelling values than the commercial organophilic clay in kerosene, Varsol, toluene and soya bean oil were obtained. (author)

  12. Water-clay interactions. Experimental study

    International Nuclear Information System (INIS)

    Clay minerals contribute to the chemical composition of soil and sediment groundwaters via surface and dissolution/precipitation reactions. The understanding of those processes is still today fragmentary. In this context, our experimental purpose is to identify the contribution of each reaction in the chemical composition of water in a water/clay System. Kaolinite, illite, montmorillonite are the reference clays. After a fine mineralogical study, the exchange equilibria between K+ and H+ are characterised. Different exchange sites are identified and the exchange capacities and selectivity coefficients are quantified. Then, mixtures of the three clays are equilibrated with acidic and basic (I≤10-2 M) solutions at 25 deg. C, 60 deg. C, 80 deg. C, during 320 days. The System evolution is observed by chemical analysis of the solutions and mineralogical analysis by TEM. We show that montmorillonite is unstable compared to the kaolinite/amorphous silica assemblage for solutions of pH<7. Aqueous silica is probably controlled by the kinetics of dissolution of the montmorillonite in moderate pH media. In more acidic solutions, amorphous silica precipitates. Al is under control of 'kaolinite' neo-formations. The use of the selectivity coefficients in a numerical simulation shows that K+ concentration depends on exchange reactions. The pH has a more complicated evolution, which is not completely understood. This evolution depends on both exchange equilibria and organic acid occurrence. In this type of experiments, we have demonstrated that the equilibrium equations between smectite and kaolinite are inexact. The problem of the thermodynamic nature of clays remains and is not resolved by these solubility experiments. (author)

  13. Repository tunnel construction in deep clay formations

    International Nuclear Information System (INIS)

    One of the objects of the Hades project at Mol, Belgium has been to evaluate the feasibility of construction of a deep repository in the Boom clay formation at depth of approximately 225 metres. The main objective of the present project was to analyse and interpret the detailed geotechnical measurements made around the Hades trial shaft and tunnel excavations and evaluate the safety of radioactive waste disposal in a repository facility in deep clay formations. Plasticity calculations and finite element analyses were used which gave results consistent with the in-situ measurements. It was shown that effective stress analysis could successfully predict the observed field behaviour. Correct modelling of the small-strain stiffness of the Boom clay was essential if reasonable predictions of the pore pressure response due to construction are to be made. The calculations undertaken indicated that, even in the long term, the pressures on the test drift tunnel lining are likely to be significantly lower than the overburden pressure. Larger long-term tunnel lining pressures are predicted for impermeable linings. A series of laboratory stress path tests was undertaken to determine the strength and stiffness characteristics of the Boom clay. The tests were conducted at appropriate effective stress levels on high-quality samples retrieved during construction of the test drift. The apparatus developed for the testing is described and the results discussed. The development of a self boring retracting pressure-meter is described. This novel in-situ testing device was specifically designed to determine from direct measurements the convergence/confinement curve relevant to tunnelling in clay formations. 44 refs., 60 figs., 3 tabs

  14. Faults in clays their detection and properties

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, G.; Carabelli, E.; Chiantore, V.; Colombo, P.F.; Gruszka, A.; Pensieri, R.; Superbo, S.; Gera, F.

    1991-12-31

    The `Faults in clays project`, a cooperative research effort between Ismes and Enea of Italy and BGS and Exeter University of the UK, has been aimed at assessing and improving the resolution capability of some high resolution geophysical techniques for the detection of discontinuities in clay formations. All Ismes activities have been carried out in Italy: they consisted in the search of one or more sites - faulted clay formations - suitable for the execution of geophysical and geotechnical investigations, in the execution of such tests and in additional geological surveys and laboratory (geotechnical and geochemical) testing. The selected sites were two quarries in plio-pleistocenic clay formations in central Italy where faults had been observed. The greatest part of the research work has been carried out in the Orte site where also two 90 m boreholes have been drilled and cored. Geophysical work at Orte consisted of vertical electrical soundings (VESs) and horizontal electrical lines (HELs), four high resolution seismic reflection lines, and in-hole and cross-hole logs. Laboratory activities were geotechnical characterization and permeability tests, and measurements of disequilibrium in the uranium decay series. At Narni, where Exeter University sampled soil gases for geochemical analyses, the geophysical work consisted in a geo-electrical survey (five VESs and two HELs), and in two high resolution reflection seismic lines. Additional investigations included a structural geology survey. The main conclusion of the research is that current geophysical techniques do not have a resolution capacity sufficient to detect the existence and determine the characteristics of faults in deep homogeneous clay formations.

  15. Faults in clays their detection and properties

    International Nuclear Information System (INIS)

    The 'Faults in clays project', a cooperative research effort between Ismes and Enea of Italy and BGS and Exeter University of the UK, has been aimed at assessing and improving the resolution capability of some high resolution geophysical techniques for the detection of discontinuities in clay formations. All Ismes activities have been carried out in Italy: they consisted in the search of one or more sites - faulted clay formations - suitable for the execution of geophysical and geotechnical investigations, in the execution of such tests and in additional geological surveys and laboratory (geotechnical and geochemical) testing. The selected sites were two quarries in plio-pleistocenic clay formations in central Italy where faults had been observed. The greatest part of the research work has been carried out in the Orte site where also two 90 m boreholes have been drilled and cored. Geophysical work at Orte consisted of vertical electrical soundings (VESs) and horizontal electrical lines (HELs), four high resolution seismic reflection lines, and in-hole and cross-hole logs. Laboratory activities were geotechnical characterization and permeability tests, and measurements of disequilibrium in the uranium decay series. At Narni, where Exeter University sampled soil gases for geochemical analyses, the geophysical work consisted in a geo-electrical survey (five VESs and two HELs), and in two high resolution reflection seismic lines. Additional investigations included a structural geology survey. The main conclusion of the research is that current geophysical techniques do not have a resolution capacity sufficient to detect the existence and determine the characteristics of faults in deep homogeneous clay formations

  16. Zeta Potential Measurements on Three Clays from Turkey and Effects of Clays on Coal Flotation

    Science.gov (United States)

    Hussain; Dem&idot;rc&idot;; özbayoğlu

    1996-12-25

    There is a growing trend of characterizing coal and coal wastes in order to study the effect of clays present in them during coal washing. Coarse wastes from the Zonguldak Coal Washery, Turkey, were characterized and found to contain kaolinite, illite, and chlorite. These three clays, obtained in almost pure form from various locations in Turkey, have been subjected to X-ray diffraction (XRD) analysis to assess their purity and zeta potential measurements in order to evaluate their properties in terms of their surface charge and point of zero charge (pzc) values. It was found from XRD data that these clays were almost pure and their electrokinetic potential should therefore be representative of their colloidal behavior. All three clay minerals were negatively charged over the range from pH 2.5 to 11. Chlorite and illite have pzc at pH 3 and pH 2.5, respectively, whereas kaolinite has no pzc. The effect of these clays in Zonguldak coal, wastes, and black waters on coal flotation was studied by floating artificial mixtures of Zonguldak clean coal (4.5% ash) and individual clay. The flotation tests on coal/individual clay revealed that each clay influences coal flotation differently according to its type and amount. Illite had the worst effect on coal floated, followed by chlorite and kaolinite. The loss of yield in coal was found to be 18% for kaolinite, 20% for chlorite, and 28% for illite, indicating the worst effect of illite and least for kaolinite during coal flotation. PMID:8978557

  17. Soft Matter Physics of Clays and Clay suspensions: structural arrest, ordering, and host-guest interactions

    OpenAIRE

    Elisabeth Lindbo, Hansen

    2013-01-01

    This thesis contains fundamental experimental studies in soft matter physics, focusing on plate-shaped hectorite and uorohectorite clays as nanomaterials with applications in the formation of glasses, gels and liquid crystals, as naturally occurring minerals, as drug carrier systems, and as hosts for CO2 storage.The first part presents fundamental studies on the physics of dispersions of clays in aqueous solvents. We find that gravity induces phase separation in aqueous suspensions of the syn...

  18. Clays and clay minerals in Bikaner: Sources, environment pollution and management

    Science.gov (United States)

    Gayatri, Sharma; Anu, Sharma

    2016-05-01

    Environmental pollution can also be caused by minerals which include natural as well as human activities. Rapid urbanization, consumerist life style, anthropogenic deeds are increasing environmental pollution day by day. Fluctuation in our ecosystem or polluted environment leads to many diseases and shows adverse effects on living organisms. The main aim of this paper is to highlight the environmental pollution from clays and clay minerals and their mitigation..

  19. Contamination of annual crops

    International Nuclear Information System (INIS)

    Results are presented from the Nordic countries dealing with the uptake of radiocaesium from soil in annual crops after the Chernobyl accident. Barley, potato, carrot cabbage and pea were selected as suitable representatives of Nordic annual crops. The transfer of radiocaesium to man from these annual crops was generally low. Common experience was that levels after the first year decreased considerably in the agricultural ecosystems, because of the absence of fresh direct fallout and the rapid, strong fixing of caesium in most soil types. Thereafter the rate of decrease was very uncertain with a large variation between localities. Agricultural practices inhibit uptake and especially resuspension by deeper placement of the contamined surface soil. Only in areas with highly organic soils, low in clay, potassium and pH, can considerable uptake through roots take place. Examples of such places with an enhanced uptake from soil are at the Swedish peat study sites in the Gaevle region, and the Faroe Islands. In such areas the addition of potassium can be recommended in cases of severe contamination. Reliable effctive ecological halflifes (T1/2eco) for content of radiocaesium in the treated species cannot be calculated from the material available. A cautious estimate of T1/2 of about 5-10 years in the period from 1987 and until today seems reasonable. Results indicate the longest T1/2eco for the Danish and Finnish mineral soils, and the shortest for the Swedish and Faroese organic soils. Aarkrog (1992) states that the ecological halflife for Chernobyl 137Cs in the Danish total diet is 3 years. The content of radiocaesium is lower in barley grain than in the vegetable species. Carrots has a lower uptake to the edible parts than vegetable species where other parts than the root are used. These uptake patterns correspond well with what is generally assumed. (orig.)

  20. Instrumental characterization of clay by XRF, XRD and FTIR

    Indian Academy of Sciences (India)

    Preeti Sagar Nayak; B K Singh

    2007-06-01

    Instrumental characterizations of the clay were performed by different techniques such as XRF, XRD and FTIR. XRF shows the chemical compositions of the clay where Al-oxide and silica oxide are present in major quantity whereas XRD confirms the presence of these minerals in clay. FTIR studies show the presence of quartz, alumina, haematite and different mineral matters.

  1. Use of clay from kangerlussuaq in the Greenlandic construction industry

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Villumsen, Arne; Ottosen, Lisbeth M.;

    2010-01-01

    Clay material from Kangerlussuaq in West Greenland was characterised and its possible use for the production of bricks, expanded clay products and inert filler material was investigated. It was generally found that it was possible to use the clay in all of the above mentioned materials, although,...

  2. Change effects in the land use about the mineral clay

    International Nuclear Information System (INIS)

    The Pampas land changes during the Quaternary, left their mark on the mineralogy of soil clays. This work is oriented to compare the mineralogical composition of the clays and the value of potassium in an eucalyptus forestation. These results show that the mineralogical illite alteration is the cause of its destruction. This clay is the main reservoir of potassium for the agricultural soils

  3. Hydrogeological modeling of radionuclide transport in low permeability media: a comparison between Boom Clay and Ypresian Clay

    Science.gov (United States)

    Huysmans, Marijke; Dassargues, Alain

    2006-05-01

    Deep low-permeability clay layers are considered as suitable environments for disposal of high-level radioactive waste. In Belgium, the Boom Clay is the reference host formation and the Ypresian Clay an alternative host formation for research and safety and feasibility assessment of deep disposal of nuclear waste. In this study, two hydrogeological models are built to calculate the radionuclide fluxes that would migrate from a potential repository through these two clay formations. Transport parameter heterogeneity is incorporated in the models using geostatistical co-simulations of hydraulic conductivity, diffusion coefficient and diffusion accessible porosity. The calculated radionuclide fluxes in the two clay formations are compared. The results show that in the Ypresian Clay larger differences between the fluxes through the lower and the upper clay boundary occur, larger total output radionuclide amounts are calculated and a larger effect of parameter heterogeneity on the calculated fluxes is observed, compared to the Boom Clay.

  4. Polymer-clay nanocomposites obtained by solution polymerization of vinyl benzyl triammonium chloride in the presence of advanced functionalized clay

    Indian Academy of Sciences (India)

    Raluca Ianchis; Dan Donescu; Ludmila Otilia Cinteza; Violeta Purcar; Cristina Lavinia Nistor; Critian Petcu; Cristian Andi Nicolae; Raluca Gabor; Silviu Preda

    2014-05-01

    Polymer-clay nanocomposites were synthesized by solution polymerization method using advanced functionalized clay and vinyl benzyl trimethyl ammonium chloride as monomer. First stage consisted in the silylation of a commercial organo-modified clay-Cl 20A using alkoxysilanes with different chain lengths. In the second step, the synthesis and characterization of polymer-nanocomposites were followed. To evaluate the clay functionalization process as well as the final polymer-clay products, thermogravimetric,X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy and three test liquid contact angles analyses were used. The loss of ammonium ions from commercial clay, the grafting degree, the lengths and the nature of alkyl chain influence the dispersion of the advanced modified clay into the polymer solution and, furthermore, the properties of the final polymer-clay nanocomposite film.

  5. An analysis on the development tendency of flying movement and connection on the horizontal bar in Brazil Olympic cycle by new rules-guided--take horizontal bar final in the 44th World Gym Championship for instance%新规则导向下巴西奥运周期单杠飞行动作及其连接发展趋势--以第44届世界体操锦标赛单杠决赛为例

    Institute of Scientific and Technical Information of China (English)

    张禄; 吴秀云; 刘金

    2014-01-01

    By using the methods of documents,statistics and video observation,this article analyzes the players ’ flying movement and its’connection’s type, difficulty,connection points and achieving quality in 44th World Gym Championship horizontal bar final, and discuss the change of the flying movement and connection on the horizontal bar in Brazil Olympic cycle by new rules-guided in order to provide some references and gist for our athletics gymnastics athletes to achieve excellent results in the new Olympic cycle.%采用文献资料法、录像观察法、数理统计法,以第44届世界体操锦标赛单杠决赛中运动员的飞行动作及其连接的类型、难度、连接加分、完成质量为主要研究内容,探讨在新规则导向下巴西奥运周期单杠飞行动作及其连接的变化,以期为我国竞技体操运动员在新一轮奥运周期比赛中取得优异成绩提供参考。

  6. Hydrogeological modeling of radionuclide transport in low permeability media: a comparison between Boom Clay and Ypresian Clay

    OpenAIRE

    Huysmans, Marijke; DASSARGUES Alain

    2006-01-01

    Deep low-permeability clay layers are considered as suitable environments for disposal of high-level radioactive waste. In Belgium, the Boom Clay is the reference host formation and the Ypresian Clay an alternative host formation for research and safety and feasibility assessment of deep disposal of nuclear waste. In this study, two hydrogeological models are built to calculate the radionuclide fluxes that would migrate from a potential repository through these two clay formations. Transport ...

  7. Hydrogeological modeling of radionuclide transport in heterogeneous low-permeability media: a comparison between Boom Clay and Ieper Clay

    OpenAIRE

    Huysmans, Marijke; DASSARGUES Alain

    2006-01-01

    Deep low-permeability clay layers are considered as possible suitable environments for disposal of high-level radioactive waste. In Belgium, the Boom Clay is the reference host formation and the Ieper Clay an alternative host formation for research and safety and feasibility assessment of deep disposal of nuclear waste. In this study, two hydrogeological models are built to calculate the radionuclide fluxes that would migrate from a potential repository through these two clay formations. Tran...

  8. Improving confidence in deep drainage estimates, for arid and semi-arid areas using multiple linear regression with percent clay content and rainfall

    Directory of Open Access Journals (Sweden)

    D. L. Wohling

    2011-05-01

    Full Text Available Deep drainage estimates are required for effective management of water resources. However, field measurements are time consuming and costly so simple empirical relationships are often used. Relationships developed between clay content of the surface soil and deep drainage have been used extensively in Australia to provide regional estimates of drainage but these relationships have been poorly justified and did not include rainfall in the relationships. Here we present a rigorous appraisal of clay content of soils and rainfall as predictors of drainage using an extensive database of field observations from across Australia. This study found that annual average rainfall and the clay content of the top 2 m of the soil are statistically significant predictors of drainage. Relationships have been defined for annual, perennial and tree type vegetation as a line of best fit along with 95 % confidence intervals. This allows the uncertainty in these drainage estimates to be assessed for the first time.

  9. Migration and sorption of strontium in clay-sand mixtures

    International Nuclear Information System (INIS)

    The migration and sorption of Sr in clay-sand mixture were investigated by batch experiment, column experiments and numerical simulation. The results showed that as the clay content in clay-sand mixture increased, the effective porosity, absorption capacity and retardation factor of the mixture for Sr increased, but the dispersion coefficient and migration velocity decreased. The migration of Sr was influenced strongly when clay content was in range of 0-25 %, but influenced weakly when clay content was more than 25 %. The experimental data was consistent with the calculated results by CXTFIT program. (author)

  10. Compressed clay and its applications. Stampflehm und seine Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Minke, G.

    1985-01-01

    This is the second book in a series books on the subject of building with clay. It contains contributions from various authors on research and practice of building with compressed clay. Building with compressed clay is a technique with a rich tradition, but which has sunk largely into oblivion in the 20th century. It was not until new machinery for working it that it again became economically interesting. Compressed clay is a useful material for walls, ceilings and floors. Stoves and furnances can also be built with it. The book also contains a list of historic clay buildings in Lower Saxony, Hamburg and Bremen. (BWI).

  11. Performance Study of the Natural Rubber Composite with Clay Minerals

    International Nuclear Information System (INIS)

    The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

  12. 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

  13. Clay mineral formation and transformation in rocks and soils

    Science.gov (United States)

    Eberl, D.D.

    1983-01-01

    Three mechanisms for clay mineral formation (inheritance, neoformation, and transformation) operating in three geological environments (weathering, sedimentary, and diagenetic-hydrothermal) yield nine possibilities for the origin of clay minerals in nature. Several of these possibilities are discussed in terms of the rock cycle. The mineralogy of clays neoformed in the weathering environment is a function of solution chemistry, with the most dilute solutions favoring formation of the least soluble clays. After erosion and transportation, these clays may be deposited on the ocean floor in a lateral sequence that depends on floccule size. Clays undergo little reaction in the ocean, except for ion exchange and the neoformation of smectite; therefore, most clays found on the ocean floor are inherited from adjacent continents. Upon burial and heating, however, dioctahedral smectite reacts in the diagenetic environment to yield mixed-layer illite-smectite, and finally illite. With uplift and weathering, the cycle begins again. Refs.

  14. Feasibility of classification of clay minerals by using PAS

    Science.gov (United States)

    Honda, Y.; Yoshida, Y.; Akiyama, Y.; Nishijima, S.

    2015-06-01

    After the nuclear power plant disaster, the evaluation of radioactive Cs kept in soil, especially in clay minerals and the elucidation of its movement are urgent subjects to promote decontamination. It is known that the extractable level of Cs depends on the sort of clay minerals. We tried to find the characteristics of clay minerals belonging to phillosilicate group using positron annihilation spectroscopy (PAS) and the relationship between the results of PAS and the amounts of substantially extracted Cs from the clay minerals. The results showed that each clay mineral was found to be distinguishable from other clay minerals by PAS and the extraction rate of Cs was different among those clay minerals, however the direct correlation between the results of PAS and the extraction rates of Cs was not found.

  15. Clay mineral type effect on bacterial enteropathogen survival in soil.

    Science.gov (United States)

    Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

    2014-01-15

    Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. PMID:24035982

  16. CLAY MINERALOGY OF INSOLUBLE RESIDUES IN MARINE EVAPORITES.

    Science.gov (United States)

    Bodine, Marc W., Jr.

    1985-01-01

    Insoluble residues from three sequences of Paleozoic marine evaporites (Retsof salt bed in western New York, Salado Formation in south-eastern New Mexico, and Paradox Member of the Hermosa Formation in southeastern Utah) are rich in trioctahedral clays. Chlorite (clinochlore), corrensite (mixed-layer chlorite-trioctahedral smectite), talc, and illite (the only dioctahedral clay) are the dominant clay minerals; serpentine, discrete trioctahedral smectite (saponite), and interstratified talc-trioctahedral smectite are sporadically abundant. These clay-mineral assemblages differ chemically and mineralogically from those observed in most continental and normal marine rocks, which commonly contain kaolinite, dioctahedral smectite (beidellite-montmorillonite), illite, mixed-layer illite-dioctahedral smectite, and, in most cases, no more than minor quantities of trioctahedral clay minerals. The distinctive clay mineralogy in these evaporite sequences suggests a largely authigenic origin. These clay minerals are thought to have formed during deposition and early diagenesis through interaction between argillaceous detritus and Mg-rich marine evaporite brines.

  17. Silt-clay aggregates on Mars

    Science.gov (United States)

    Greeley, R.

    1979-01-01

    Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates together. Various laboratory experiments conducted since the 19th century, and as reported here for simulated Martian conditions, show that both the magnitude and sign of electrical charges on windblown particles are functions of particle velocity, shape and composition, atmospheric pressure, atmospheric composition and other factors. Electrical charges have been measured for saltating particles in the wind tunnel and in the field, on the surfaces of sand dunes, and within dust clouds on earth. Similar, and perhaps even greater, charges are proposed to occur on Mars, which could form aggregates of silt and clay size particles

  18. Organoclays obtaining starting up of clays sodium

    International Nuclear Information System (INIS)

    Clays have several applications in many areas of fields of technology, however, modification of these materials using organic compounds can be performed to obtain further hydrophobic materials, for applications in the adsorption of organic pollutants. This study aimed to analyze the effects of modifying two clays using sodium quaternary ammonium surfactants through ion exchange reaction process, in obtaining organoclays. The samples with sodium and organoclays were characterized by the techniques of X-ray diffraction (XRD), Infrared Spectroscopy in the region (IV), Gravimetric and Differential Thermal Analysis (DTA / TG) and organic adsorption tests. The results show that the process of obtaining organoclay is efficient, and materials have the potential for future applications in removing organic contaminants. (author)

  19. Humidity Dependent Extinction of Clay Aerosols

    Science.gov (United States)

    Greenslade, M. E.; Attwood, A. R.

    2010-12-01

    Aerosols play an important role in the Earth’s radiative balance by directly scattering and absorbing radiation. The magnitude of aerosol forcing can be altered by changes in relative humidity which cause aerosol size, shape and refractive index to vary. To quantify these effects, a custom cavity ring down instrument operated at 532 nm with two sample channels measures aerosols extinction under dry conditions and at elevated humidity. The optical growth, fRH(ext), is determined as a ratio of the extinction cross section at high relative humidity to that under dry conditions. Three key clay components of mineral dust and mixtures of clay components with ammonium sulfate are investigated using this method. Experimentally obtained optical growth is compared with physical growth factors from the literature and our work determined using several different techniques. Further, Mie theory calculations based on published optical constants are compared with experimental results. Differences between theory and experiment will be discussed.

  20. Clay-based geothermal drilling fluids

    Energy Technology Data Exchange (ETDEWEB)

    Guven, N.; Carney, L.L.; Lee, L.J.; Bernhard, R.P.

    1982-11-01

    The rheological properties of fluids based on fibrous clays such as sepiolite and attapulgite have been systematically examined under conditions similar to those of geothermal wells, i.e. at elevated temperatures and pressures in environments with concentrated brines. Attapulgite- and sepiolite-based fluids have been autoclaved at temperatures in the range from 70 to 800/sup 0/F with the addition of chlorides and hydroxides of Na, K, Ca, and Mg. The rheological properties (apparent and plastic viscosity, fluid loss, gel strength, yield point, and cake thickness) of the autoclaved fluids have been studied and correlated with the chemical and physical changes that occur in the clay minerals during the autoclaving process.

  1. Organically modified clay removes oil from water

    International Nuclear Information System (INIS)

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

  2. Thermal behaviour of organically modified clays

    Czech Academy of Sciences Publication Activity Database

    Plevová, Eva; Vaculíková, Lenka; Vítámvásová, E.; Šugárková, Věra; Martynková, G.S.

    Ostrava : VŠB-TUO, 2013 - (Holešová, S.; Martynková, G.), s. 114-114 ISBN 978-80-7329-361-1. [NANO OSTRAVA 2013 - 3rd Nanomaterials and Nanotechnology Meeting. Ostrava (CZ), 17.06.2013-20.06.2013] R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : clay minerals * alkylammonium cations * intercalation * thermal analysis Subject RIV: CB - Analytical Chemistry, Separation

  3. Structure and theoretical calculations of clay minerals

    International Nuclear Information System (INIS)

    Structural and spectroscopic methods are combined to determine the full structure, including hydrogen atom positions, of dickite, which is a member of the kaolin group. Using the structural information obtained, quantum chemical calculations are performed on these kaolin group minerals. Special emphasis is laid on the relationship between the experimentally derived structure and theory. Finally, the application of quantum chemical methods to study clay minerals at several levels of approximation is reviewed

  4. Phosphorus speciation in Swedish agricultural clay soils

    OpenAIRE

    Eriksson, Ann Kristin

    2016-01-01

    Phosphorus (P) is an important element for crop production, but build-up of excess soil P can promote P leaching and eutrophication of surface waters. To better understand the dynamics of P release from soil to waters, more knowledge is needed about sorption patterns and P speciation in agricultural soils. Two new indices were developed to assess the importance of P sorption to hydroxy-interlayered clay minerals, and to evaluate the amount of hydroxy-interlayering and hydroxy-interlayer ...

  5. Can clays ensure nuclear waste repositories?

    OpenAIRE

    Zaoui, A.; Sekkal, W.

    2015-01-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmori...

  6. Mullins' effect in polymer/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Klitkou, Rasmus

    2012-01-01

    Abstract. Experimental data are reported on polypropylene/clay nanocomposites in uniaxial cyclic tensile tests at room temperature (oscillations between maximum strains and the zero minimum stress with maximum strains increasing monotonically with number of cycles). Observations reveal fading of...... nanocomposites, and adjustable parameters in the stress–strain relations are found by fitting the experimental data. Ability of the model to predict the fading memory phenomenon is confirmed by numerical simulation....

  7. Mechanisms of gas transport in clay barriers

    OpenAIRE

    Alonso Pérez de Agreda, Eduardo; Olivella Pastallé, Sebastià; Arnedo Gaute, Diego

    2006-01-01

    Laboratory experiments show that preferential paths develop through saturated impervious clay bodies. A procedure to integrate gas transmission discontinuities into a general THM formulation is described. The technique has been incorporated into a general purpose FE THM code (CODE_BRIGHT) and it has been used to reproduce gas transmission experiments in specimens. The experimentally observed peaks in gas pressure and flow rates, when breakthrough conditions are reached, are reproduced. The pa...

  8. Pneumoconiosis in Cornish china clay workers.

    OpenAIRE

    Oldham, P D

    1983-01-01

    A radiological survey of men employed in the china clay industry in Cornwall was carried out in 1977. Each man completed a short questionnaire on respiratory symptoms and smoking habits, his occupational history was determined, and his forced expiratory volume and vital capacity were measured. The radiographs were read independently by three observers, using the 1980 ILO classification. Of the 1728 men in the study, 23 had had dust exposure elsewhere, mostly in tin mining, and were excluded. ...

  9. 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

  10. Strengthening and stress relaxation of Opalinus Clay

    International Nuclear Information System (INIS)

    In the near-field of underground openings the rock will undergo damage. Closure and re-establishment of the initial rock integrity may be assisted by long-term creep of the un-disturbed clay stone in the far-field, thus promoting self sealing processes in the dilated clay-portions by convergence. Therefore, the understanding of creep is essential for the assessment of the long-term post-closure behaviour in a waste repository. Stress relaxation testing on pre-strained Opalinus Clay specimens from the Mont Terri Rock Laboratory was performed to check if a time dependent, though non-dilatant deformation is present. The stress relaxation behaviour of the four tested specimens was investigated during triaxial loading using different sample orientations, i.e. referring to the bedding, and under drained or und-drained conditions, respectively. To suppress artefacts as far as possible, e.g. due to sampling and rock preparation, several loading cycles were performed. After these repeated turns of loading, the stress relaxation was found to be independent from loading geometry or draining anymore. In general, the normalized stress relaxation curves plot in a narrow band. The experimental results are discussed on the basis of common equations for the stress-strain-behaviour which may be appropriate to model the recorded time dependent stress relaxation. (authors)

  11. Spectromicroscopy of Fe distributions in clay microcrystals

    Energy Technology Data Exchange (ETDEWEB)

    Grundl, T. [Univ. of Wisconsin, Milwaukee, WI (United States); Cerasari, S.; Garcia, A. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Clays are ubiquitous crystalline particles found in nature that are responsible for contributing to a wide range of chemical reactions in soils. The structure of these mineral particles changes when the particle is hydrated ({open_quotes}wet{close_quotes}), from that when it is dry. This makes a study of the microscopic distribution of chemical content of these nanocrystals difficult using standard techniques that require vacuum. In addition to large structural changes, it is likely that chemical changes accompany the drying process. As a result, spectroscopic measurements on dried clay particles may not accurately reflect the actual composition of the material as found in the environment. In this work, the authors extend the use of the ALS Spectromicroscopy Facility STXM to high spectral and spatial resolution studies of transition metal L-edges in environmental materials. The authors are studying mineral particles of montmorillonite, which is an Fe bearing clay which can be prepared with a wide distribution of Fe concentrations, and with Fe occupying different substitutional sites.

  12. 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.

  13. Long-term copper availability and adsorption in a sludge-amended Davidson clay loam

    OpenAIRE

    Anderson, Martha Ann

    1997-01-01

    A single application of aerobically digested sewage sludge was applied by Rappaport et al. (1988) in 1984 at rates up to 210 dry Mt ha-1 on a Davidson clay loam (clayey, kaolinitic, thermic, Rhodic KandiuduIts). The heavily contaminated sludge supplied up to 760 kg Cu and 620 kg Zn haha-1, which are below current cumulative limits, but above annual loading limits for these metals (USEPA, 1993). Rappaport et al. (1988) reported an increase in DTPA extractable Cu and Zn with incr...

  14. Atrazine biodegradation modulated by clays and clay/humic acid complexes

    International Nuclear Information System (INIS)

    The fate of pesticides in the environment is strongly related to the soil sorption processes that control not only their transfer but also their bioavailability. Cationic (Ca-bentonite) and anionic (Layered Double Hydroxide) clays behave towards the ionisable pesticide atrazine (AT) sorption with opposite tendencies: a noticeable sorption capacity for the first whereas the highly hydrophilic LDH showed no interactions with AT. These clays were modified with different humic acid (HA) contents. HA sorbed on the clay surface and increased AT interactions. The sorption effect on AT biodegradation and on its metabolite formation was studied with Pseudomonas sp. ADP. The biodegradation rate was greatly modulated by the material's sorption capacity and was clearly limited by the desorption rate. More surprisingly, it increased dramatically with LDH. Adsorption of bacterial cells on clay particles facilitates the degradation of non-sorbed chemical, and should be considered for predicting pesticide fate in the environment. - The biodegradation rate of atrazine was greatly modulated by adsorption of the pesticide and also bacterial cells on clay particles.

  15. 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)

  16. 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.

  17. Influence of clay organic modifier on morphology and performance of poly(ε-caprolactone/clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Nikolić Marija S.

    2015-01-01

    Full Text Available Two series of poly(e-caprolactone nanocomposites with different organo-modified clays (1 to 8 wt% were prepared by the solution casting method. Organoclays with polar (Cloisite®C30B and nonpolar (Cloisite®C15A organic modifier and with different miscibility with poly(e-caprolactone matrix, were chosen. Exfoliated and/or intercalated nanocomposite’s structures were obtained by using high dilution and an ultrasonic treatment for the composite preparation. The effect of the surface modification and clay content on the morphology, mechanical and thermal properties of the nanocomposites was studied. Scanning electron microscopy excluded the formation of microcomposite. The wide-angle X-ray diffraction analysis revealed that the tendency toward exfoliated structure is higher for the Cloisite®C30B, which had better miscibility with poly(e-caprolactone matrix. Differences in spherulites’ sizes and morphology between two series of the nanocomposites were observed by the optical microscopy performed on as-casted films. Enthalpies of fusion and degrees of crystallinity were higher for nanocomposites than for neat poly(e-caprolactone and increase with the clay loading in both series, as a consequence of the clay nucleating effect. Decreased thermal stability of nanocomposites was ascribed to thermal instability of organic modifiers of the clays. The Halpin-Tsai model was used to compare the theoretically predicted values of the Young’s modulus with experimentally obtained ones in tensile tests.[Projekat Ministarstva nauke Republike Srbije, br. 172062

  18. Characteristics of Non-Allophanic Andisols derived from Low Activity Clay Regoliths in Nilgiri Hills (Southern India)

    OpenAIRE

    Caner, Laurent; Bourgeon, G.; Toutain, François; Herbillon, A.J.

    2000-01-01

    Low activity clay soils on old planation surfaces of the tropics are generally considered as stable end points of soil formation. It is therefore surprising to find Andosols on them. We characterised the properties of six profiles representative of these soils in the Western part of Nilgiri Hills (2000–2500 m above mean sea level), Southern India, where the present climatic conditions are cool (mean annual temperature 15°C) and humid (mean annual rainfall 2500 mm). Thick (50–80 cm) dark–reddi...

  19. HDPE/clay hybrids: the effect of clay modified with poly(diphenyl siloxanes) on thermal and rheological properties

    International Nuclear Information System (INIS)

    Poly(diphenyl siloxanes) (PDPhS) were synthesized in presence of organophilic clay in order to modify its nano structure. Two silane monomers were used: dimethoxydiphenylsilane and dichlorodiphenylsilane. The following characterizations were performed for all clays: XRD, FTIR and TGA/DTG. These siloxane-modified clays were more hydrophobic and had enhanced thermal stability. Solvent extraction was carried out in the siloxane-modified clays and the PDPhS soluble fraction analyzed according the molecular weight via GPC. The presence of free and grafted oligomers on clay surface was identified. The modified clays were added to HDPE by melt processing to obtain HDPE/clay hybrids which exhibited marked differences in the rheological behavior when compared with neat HDPE. (author)

  20. REE and (э)Nd of clay fractions in sediments from the eastern Pacific Ocean: Evidence for clay sources

    Institute of Scientific and Technical Information of China (English)

    LIU Jihua; SHI Xuefa; CHEN Lirong; HUANG Yongyang; WANG Yinxi; CUI Yingchun; BU Wenrui

    2005-01-01

    Clay fractions in the non-calcareous surface sediments from the eastern Pacific were analyzed for clay minerals, REE and 143Nd/144Nd. Montmorillonite/illite ratio (M/I ratio), total REE contents ((REE), LREE/HREE ratio and cerium anomaly (бCe) may effectively indicate the genesis of clay minerals. Clay fractions with M/I ratio >1, бCe (0.85, (REE (400 μg/g, LREE/HREE ratio (4, and REE patterns similar to those of pelagic sediments are terrigenous and autogenetic mixed clay fractions and contain more autogenetic montmorillonite. Clay fractions with M/I ratio <1, бCe=0.86 to 1.5, ΣREE=200 to 350 μg/g, LREE/HREE ratio (6 and REE distribution patterns similar to that of China loess are identified as terrigenous clay fraction. The 143Nd/144Nd ratios or (э)Nd values of clay fractions inherit the features of terrigenous sources of clay minerals. Clay fractions are divided into 4 types according to (э)Nd values. Terrigenous clay minerals of type I with the (э)Nd values of -8 to -6 originate mainly from North American fluvial deposits. Those of type II with the (э)Nd values of -9 to -7 are mainly from the East Asia and North American fluvial deposits. Those of type III with (э)Nd values of -6 to -3 could come from the central and eastern Pacific volcanic islands. Those of type IV with (э)Nd values of -13 to -12 may be from East Asia eolian. The terrigenous and autogenetic mixed clay fractions show patchy distributions, indicating that there are volcanic or hot-spot activities in the eastern Pacific plate, while the terrigenous clay fractions cover a large part of the study area, proving that the terrigenous clay minerals are dominant in the eastern Pacific.

  1. Role of clay as catalyst in Friedel–Craft alkylation

    Indian Academy of Sciences (India)

    Tanushree Choudhury; Nirendra M Misra

    2011-10-01

    Solid acids have become increasingly important for many liquid-phase industrial reactions these days. Montmorillonite clays (2:1 clay mineral) have been used as efficient solid acid catalysts for a number of organic and liquid phase reactions and offer several advantages over classic acids. Tailor made catalysts can be prepared from clays by suitably adjusting their acidity and surface area by acid activation. In the present work, preparation, characterization and performance of Pt (II) clays, Cu (II) clays, acid clay, and sol–gel hybrids of Cu (II) clays as solid catalysts in a test Friedel–Craft alkylation reaction of benzyl chloride with toluene using differential scanning calorimeter (DSC) are reported. Product formation has been analysed by FTIR spectroscopy. The main objective of this work is to show how clay as a solid catalyst affects reaction rates and activation energies. Acidity and dispersion of solid catalysts are twomain factors which govern a catalysis reaction. Kinetic parameter analysis and XRD studies confirm that acid Pt (II) clay and Pt (II) clay dispersed by natural dispersants aremore effective catalysts. In contrast to the reactions using AlCl3, the experimental conditions are non-polluting and the final work up does not require any aqueous treatment.

  2. Polypropylene–clay composite prepared from Indian bentonite

    Indian Academy of Sciences (India)

    Madhuchhanda Sarkar; Kausik Dana; Sankar Ghatak; Amarnath Banerjee

    2008-02-01

    In the present work, a set of experimental polypropylene (PP) clay composites containing pristine bentonite clay of Indian origin has been prepared and then characterized. The polymer clay composites are processed by solution mixing of polypropylene with bentonite clay using a solvent xylene and high speed electric stirrer at a temperature around 130°C and then by compression molding at 170°C. The mechanical properties of PP–clay composites like tensile strength, hardness and impact resistance have been investigated. Microstructural studies were carried out using scanning electron microscope and transmission electron microscope and the thermal properties were studied using differential scanning calorimeter. Mechanical properties of the prepared composites showed highest reinforcing and toughening effects of the clay filler at a loading of only 5 mass % in PP matrix. Tensile strength was observed to be highest in case of 5 mass % of clay loading and it was more than 14% of that of the neat PP, while toughness increased by more than 80%. Bentonite clay–PP composite (5 mass %) also showed 60% increase in impact energy value. However, no significant change was observed in case of hardness and tensile modulus. Higher percentages of bentonite clay did not further improve the properties with respect to pristine polypropylene. The study of the microstructure of the prepared polymer layered silicate clay composites showed a mixed morphology with multiple stacks of clay layers and tactoids of different thicknesses.

  3. 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.

  4. Textile dye removal by natural clay--case study of Fouchana Tunisian clay.

    Science.gov (United States)

    Errais, E; Duplay, J; Darragi, F

    2010-04-01

    A significant amount of unused dyes remain in textile industry wastewater, the treatment of which presents a great challenge, particularly in semi-arid countries where water resources are of great concern. Liquid-phase adsorption is highly efficient for the removal of dyes and adsorbents, for example, activated carbons are used to treat wastewater, but are expensive. Clays are cheaper and several works have showed their high pollutant adsorption capacity in cases of environmental problems. The aim of this work is to present the use of clay as a means of textile wastewater treatment and colour adsorption. The adsorbent used in this study is natural clay from the Fouchana region (Tunisia), which contains 60% smectites, 30% kaolinite and 10% illite, in which the cation-exchange capacity is about 50 meq/ 100 g of clay. Two types of waters were treated: one from a leaching textile industry and another from a dyeing industry. Moreover the treatment by clay was compared to the treatment by a coagulation flocculation standard method. The experimental results show that the treatment by natural clay is more efficient than the conventional treatment by coagulation flocculation. It allowed decolorization of the dye effluent and a decrease down to 97% for biochemical demand for oxygen, 93% for suspended matter, 95% for chemical demand for oxygen and 76% for the spectral absorption coefficient. Thus, the quality of dye wastewater has reached the Tunisian standards of releases (NT 106.02 and 106.03, 1989), and as such it makes it possible to test wastewater at the industrial scale. PMID:20450111

  5. Fe(0)-clays interactions at 90°C under anoxic conditions: a comparative study between clay fraction of Callovo-Oxfordian and other purified clays

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste it is of prime importance to understand the interactions between the saturated clay formation and steel containers. This can be achieved through an in-depth analysis of iron-clay interactions. Previous studies on the subject investigated the influence of solid/liquid ratio, iron/clay ratio, temperature and reaction time. The aim of the present study is to explain Callovo-Oxfordian-Fe(0) interactions by determining the role of each mineral phases present in the Callovo-Oxfordian (clay minerals, quartz, carbonates and pyrite) on the mechanisms of interaction between metal iron and clay particles. In that context, it is especially important to understand in detail the influence of clay nature and to obtain some insight about the relationships between interaction mechanisms at the molecular scale and crystallographic properties (particle size, TO or TOT layers, amount of edge faces...). The influence of the combination of different clays and the addition of other minerals must also be studied. In a first step, the Callovo-Oxfordian argillite from the Andra's underground research laboratory was purified to extract the clay fraction (illite, illite-smectite, kaolinite and chlorite). Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L-1, CaCl2 0.04 M.L-1) for durations of one, three or nine months in the presence of metallic iron powder. Experiments without iron were used as control. The iron/clay ratio was fixed at 1/3 with a solid/liquid ratio of 1/20. The above mentioned experiments were also carried out in parallel on other purified clays: two smectites (Georgia bentonite and SWy2 from the Clay Minerals Society), one illite (illite du Puy) and one kaolinite (KGa2, from the Clay Minerals society). At the end of the experiments, solid and liquid phases were separated by

  6. Inventorying Toronto's single detached housing stocks to examine the availability of clay brick for urban mining.

    Science.gov (United States)

    Ergun, Deniz; Gorgolewski, Mark

    2015-11-01

    This study examines the stocks of clay brick in Toronto's single detached housing, to provide parameters for city scale material reuse and recycling. Based on consensus from the literature and statistics on Toronto's single detached housing stocks, city scale reusable and recyclable stocks were estimated to provide an understanding of what volume could be saved from landfill and reintroduced into the urban fabric. On average 2523-4542 m(3) of brick was determined to be available annually for reuse, which would account for 20-36% of the volume of virgin brick consumed in new house construction in 2012. A higher volume, 6187 m(3) of brick, was determined to be available annually for recycling because more of the prevalence of cement-based mortar, which creates challenges for brick reuse in Toronto. The results demonstrated that older housing containing reusable brick were being mostly landfilled and replaced with housing that contained only recyclable brick. PMID:25912626

  7. Study of polymeric hydrogels with inorganic nanoparticles of clay

    International Nuclear Information System (INIS)

    Nanoscience has been applied in research of intelligent systems for drug delivery. The use of biodegradable synthetic polymers and in diagnostics and therapy has stimulated the application of nanotechnology in polymeric systems with new structures and new materials composing among these materials are hydrogels. Hydrogel with dispersed clay is a new class of materials that combine flexible and permeability of the hydrogels with the high efficiency of the clay to adsorb different substances. We evaluated the behaviour of swelling, gel fraction and thermal stability among the hydrogels obtained by poly (vinyl alcohol) (PVAl) with clay and poly (N-2-vinyl-pyrrolidone) (PVP) with clay. While, observed that the hydrogels showed swelling clay PVAl meaningful, the clay PVP hydrogels showed swelling more consistent after four hours of testing

  8. Polyaniline and mineral clay-based conductive composites

    Directory of Open Access Journals (Sweden)

    Samantha Oliveira Vilela

    2007-09-01

    Full Text Available Composite materials have attracted the attention of numerous researchers due to the distinct properties shown by this class of materials and the mineral clay used in their synthesis. In this study, conductive composites were obtained by mixing polyaniline (PAni with clay (kaolinite and montmorillonite. The aniline was polymerized in a medium with clay and the powder was characterized by X ray diffraction, electrical conductivity and morphology. The results suggest PAni chain linearization in a kaolinite medium. The addition of montmorillonite resulted in PAni chain linearization and intercalation of mineral clay, although the montmorillonite was not pretreated. The PAni-clay composites showed an electrical conductivity of 0.01 S.cm-1, which appeared not to be influenced by the amount of clay used.

  9. Characterization of organophilic attapulgite clay from state of Piaui

    International Nuclear Information System (INIS)

    The attapulgite is mineral clay typically fibrous. It owns a superficial area around 125 to 210 m²/g, cationics transfer capacity from 20 to 30 mill equivalents per 100g of clay, high capacity of sorption, considerable decolourizer capacity, chemical inertia and maintenance of thixotropics properties in the presence of electrolytes. The objective of this work was to perform the chemical modification of attapulgite original from state of Piaui - Brazil, for applications in polymeric nanocomposites. The chemical composition of clay without modification was determined by X-Ray Diffraction. The natural clay and organophilizated one were characterized by X-Ray Diffraction (XRD), by Fourier Transform Infra-Red spectroscopy (FTIR), and Foster's swelling. The obtained results indicated the presence of characteristics groups of the salt in the clay, alteration in its chemical composition, evidencing that the chemical modification in the clay was efficient, could the same be applied in preparation of polymeric nanocomposites. (author)

  10. Oxygen barrier property of polypropylene-polyether treated clay nanocomposite

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available Polypropylene (PP nanocomposites were obtained by solution blending of polyether treated montmorillonite and PP, with a coupling agent of maleic anhydride grafted polypropylene (PP-g-MA. The composition of the inorganic clay was varied in 1, 2 and 5 phr (parts of clay per hundred of PP by mass while films of the composites were obtained via compression molding. Wide-angle X-ray scattering (WAXS showed nanocomposites in which silicate layers were exfoliated and intercalated with respect to the different clay ratios. The morphology and gas permeability of hybrids prepared with organoclay were compared. Morphological studies using transmission electron microscopy showed most clay layers were dispersed uniformly in the PP matrix. Some tactoids of agglomerated nanoparticles were detected, as clay content increased. The oxygen permeability for all the hybrids for clay loadings were reduced by 30% of the corresponding values for pure PP.

  11. 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)

  12. Tritium and iodide diffusion through opalinus clay

    International Nuclear Information System (INIS)

    The International Mont Terri Project started in 1995 under the patronage of the Swiss National Hydrological and Geological Survey (SNHGS), and has the authorization of the Republique et Canton du Jura. The underground rock laboratory is located at the northwestern part of Switzerland (Canton Jura), in and beside the reconnaissance gallery of the Mont Terri motorway tunnel, one of the several tunnels of the A16 'Transjurane' motorway. The depth of overburden above the rock laboratory is approximately 300 meters. The project is aimed to investigate the geological, hydrogeological, geochemical and rock mechanical properties of the Opalinus Clay for assessing the feasibility and safety of a repository for radioactive waste placed in this type of host rock. One of the issues under study is radionuclide migration by diffusion through clays. As a part of this investigation, an interlaboratory comparison on small-scale diffusion experiments was carried out by three research laboratories: AEA Technology (UK), SCK-CEN (Belgium) and CIEMAT (Spain). The radionuclides investigated were tritium and iodine. This paper concerns to the methodological approach and results of the experiments undertaken by CIEMAT. The effective diffusion coefficients were measured for tritiated water and iodine (as Γ), resulting larger for tritium [(1.7±0.4)x10-11 m2/s] than for iodide [(2.7±0.3)x10-12 m2/s]. The porosity available for diffusion was calculated by using the time-lag method, but some results seemed unrealistic and showed a large variability. In general, tritium exhibited higher values of porosity than iodide (17 to 26% and 12 to 17%, respectively), which were consistent with the anion exclusion affecting the distribution of iodide into the clay pores. Copyright (2001) Material Research Society

  13. Uranyl adsorption at clay mineral surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Roesch, N.

    2014-07-01

    This first exemplary survey of actinide adsorption at complex clay mineral surfaces, which provided new insights at the atomic level, will be extended to other pertinent adsorbates like neptunyl NpO{sub 2}{sup +} and more complex minerals like iron-substituted phyllosilicates. In this way we will check if the concepts developed so far can be applied more generally, to support the interpretation of upcoming experiments. An essential facet of these studies will be to account also for the dynamical nature of the mineral/water interface by means of exemplary dynamical simulations. (orig.)

  14. Adsorption Behavior of Plutonium on Clay

    Institute of Scientific and Technical Information of China (English)

    LONG; Hao-qi; BAO; Liang-jin; SONG; Zhi-xin; WANG; Bo

    2013-01-01

    In this study,the adsorption distribution ratios of Pu in the Longdong clays were measured with batch method under hypoxic conditions,and the influence of the liquid-solid ratio and pH on the adsorption distribution ratio also was discussed.The initial concentration of Pu is about 1×10-10 mol/L,and the solution pH value was adjusted with NaOH or HClO4.The temperature of experiments was(30±

  15. Iodine sorption on loess and clay samples

    International Nuclear Information System (INIS)

    Sorption batch experiments were performed to evaluate the ability of Saligny geologic formations to retard the main radionuclides that could be released from the disposal facility by dissolution/leaching processes. This paper presents the results obtained for iodine, one of the long-lived radionuclides present in the radioactive waste generated from Cernavoda NPP operation and decommissioning. Experimental results suggest that loess and clay samples present in Saligny site can not retard significantly the iodine transport and this radionuclide will be transported at velocities as similar to those in case of the ground water. (authors)

  16. Identification of clay minerals by infrared spectroscopy and discriminant analysis

    OpenAIRE

    Ritz, Michal; Vaculíková, Lenka; Plevová, Eva

    2010-01-01

    Identification of clay minerals based on chemometric analysis of measured infrared (IR) spectra was suggested. IR spectra were collected using the diffuse reflection technique. Discriminant analysis and principal component analysis were used as chemometric methods. Four statistical models were created for separation and identification of clay minerals. More than 50 samples of various clay mineral standards from different localities were used for the creation of statistical models. The results...

  17. Polyaniline and mineral clay-based conductive composites

    OpenAIRE

    Samantha Oliveira Vilela; Mauro Alfredo Soto-Oviedo; Ana Paula Fonseca Albers; Roselena Faez

    2007-01-01

    Composite materials have attracted the attention of numerous researchers due to the distinct properties shown by this class of materials and the mineral clay used in their synthesis. In this study, conductive composites were obtained by mixing polyaniline (PAni) with clay (kaolinite and montmorillonite). The aniline was polymerized in a medium with clay and the powder was characterized by X ray diffraction, electrical conductivity and morphology. The results suggest PAni chain linearization i...

  18. Nano dimensional hybrid organo-clay Langmuir-Blodgett films

    OpenAIRE

    Hussain, Syed Arshad; Chakraborty, S; Bhattacharjee, D.

    2014-01-01

    Clay mineral particles are interesting nanosized building blocks due to their high aspect ratio and the chemical properties. The main interest in this nanosized building blocks results essentially from the colloidal size and the permanent structural charge of the particles. Smectites or swelling clay minerals are naturally occurring nanomaterials that can be fully delaminated to elementary clay mineral platelets in dilute aqueous dispersion. This dilute aqueous smectite suspensions are well s...

  19. Desorption of toluene from modified clays using supercritical carbon dioxide

    OpenAIRE

    Carneiro D. G. P.; Mendes M.F.; Coelho G. L. V.

    2004-01-01

    The main objective of this work is to study the regeneration capacity of modified clays using supercritical fluid. These modified clays are used as organic compound adsorvents. The experimental step was done using a packed column with the clay contaminated by toluene. The results obtained showed the influence of the density of the supercritical CO2 and of the organic modifier in the desorption process. These data were modeled with first- and second-order models. Better results were obtained u...

  20. LABORATORY TESTING OF BENTONITE CLAYS FOR LANDFILL DESIGN AND CONSTRUCTION

    OpenAIRE

    Biljana Kovačević Zelić; Dubravko Domitrović; Želimir Veinović

    2007-01-01

    Top and bottom liners are one of the key construction elements in every landfill. They are usually made as compacted clay liners (CCLs) composed of several layers of compacted clay with strictly defined properties or by the use of alternative materials such as: GCL – geosynthetic clay liner, BES – bentonite enhanced soils or bentonite/polymer mixtures. Following the state of the art experiences in the world, GCLs are used in Croatian landfills for several years, as well. Depending upon the lo...

  1. Identification of Clay Minerals by Infrared Spectroscopy and Discriminant Analysis

    OpenAIRE

    Ritz, Michal; Vaculíková, Lenka; Plevová, Eva

    2010-01-01

    Identification of clay minerals based on chemometric analysis of measured infrared (IR) spectra was suggested. IR spectra were collected using the diffuse reflection technique. Discriminant analysis and principal component analysis were used as chemometric methods. Four statistical models were created for separation and identification of clay minerals. More than 50 samples of various clay mineral standards from different localities were used for the creation of statistical models. The results...

  2. Decontamination of radioactive waste fission products by treated natural clays

    International Nuclear Information System (INIS)

    The removal of carrier free long living fission products such as iodine-131, strontium-90 and cesium-137 by treated local clays is successfully achieved with large capacity. Iodine-131 which is difficultly adsorbed has been removed completely by silver treated phosphate clay. Strontium-90 and cesium-137 have been almost removed by adequate heat treating of the clays. The results of column experiments agree well with the authors' batch experiments. (author)

  3. Radiation-induced defects in clay minerals : a review

    OpenAIRE

    Allard, T.; Balan, Etienne; Calas, G.; Fourdrin, C.; Morichon, E.; Sorieul, S.

    2012-01-01

    Extensive information has been collected on radiation effects on clay minerals over the last 35 years, providing a wealth of information on environmental and geological processes. The fields of applications include the reconstruction of past radioelement migrations, the dating of clay minerals or the evolution of the physico-chemical properties under irradiation. The investigation of several clay minerals, namely kaolinite, dickite, montmorillonite, illite and sudoite, by Electron Paramagneti...

  4. Erosion of clay-based grouts in simulated rock fractures

    International Nuclear Information System (INIS)

    The paper presents a laboratory study on the erosion of clay-based grouts in a simulated rock fracture and in a simulated rock fracture network. The apparatus specially constructed for these experiments and the testing procedure are described. The testing results have shown that a partially eroded clay-based grout may still be effective in sealing rock fractures and that the addition of cement in a clay grout can minimize erosion

  5. Se behaviour in the Boom Clay system: spectroscopic evidence

    OpenAIRE

    Breynaert, Eric; Scheinost, Andreas C.; Dom, Dirk; Vancluysen, Jacqueline; Maes, André

    2009-01-01

    In Belgium, the Boom Clay formation is studied as a reference host formation for the geological disposal of high-level and long-lived radioactive waste for more than 30 years. This formation mainly consists of mixed clay minerals (illite, interstratified illite-smectite), pyrite and immobile and dissolved natural organic matter. Since it provides good sorption capacities, very low permeability, and chemically reducing conditions due to the presence of pyrite (FeS2), the Boom clay formation it...

  6. Studies on the acid activation of Brazilian smectitic clays

    OpenAIRE

    Francisco R. Valenzuela Díaz; Pérsio de Souza Santos

    2001-01-01

    Fuller's earth and acid activated smectitic clays are largely used as bleaching earth for the industrial processing of vegetable, animal and mineral oils and waxes. The paper comments about the nomenclature used for these materials, the nature of the acid activation of smectitic clays (bentonites), activation laboratory procedures and presents a review of the acid activation of bentonites from 20 deposits from several regions of Brazil. The activated clays were tested and show good decolorizi...

  7. Characterization of some clay deposits in South West Nigeria

    OpenAIRE

    Fatai Olufemi ARAMIDE; Kenneth Kanayo ALANEME; Peter Apata OLUBAMBI; Joseph Olatunde BORODE

    2014-01-01

    Clay minerals are the most important industrial minerals whose application is dependent on its structure and chemical composition. Mineralogical, chemical compositions, phase constitutions, and microstructural morphology of certain clay minerals from three different deposits in south western Nigeria were investigated using state-of-the-art equipment. These were done with the intention of determining the appropriate application for the clay minerals. It was observed that the major phases in th...

  8. Valorization and inertization of galvanic sludge waste in clay bricks

    OpenAIRE

    Pérez-Villarejo, L.; Martínez-Martínez, S; Carrasco-Hurtado, B.; Eliche-Quesada, D.; Ureña-Nieto, C.; Sánchez-Soto, Pedro José

    2015-01-01

    Galvanic sludge wastes (GSW) are produced by the physico-chemical treatments of wastewater generated by electroplating plants. These materials have a significant potential for the production of clay ceramic bricks. This paper focuses on the viability of the inertization of heavy metals from GSW mixed with clays. The original materials were obtained by mixing three types of raw clay (red, yellow and black) in equal parts with GSW. These mixtures were characterized by XRD, XRF, and chemical ele...

  9. 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...

  10. Structure–property relationship of specialty elastomer–clay nanocomposites

    Indian Academy of Sciences (India)

    Anirban Ganguly; Madhuchhanda Maiti; Anil K Bhowmick

    2008-06-01

    The present work deals with the synthesis of specialty elastomer [fluoroelastomer and poly (styrene--ethylene-co-butylene--styrene (SEBS)]–clay nanocomposites and their structure–property relationship as elucidated from morphology studies by atomic force microscopy, transmission electron microscopy and X-ray diffraction and physico-mechanical properties. Due to polarity match, hydrophilic unmodified montmorillonite clay showed enhanced properties in resulting fluoroelastomer nanocomposites, while hydrophobic organo-clay showed best results in SEBS nanocomposites.

  11. Clay body wrap with microcurrent: effects in central adiposity

    OpenAIRE

    Noites, Andreia; Melo, A. S. C; Moreira, J S; Couto, Miriam F.; Argel Melo, C.

    2013-01-01

    Introduction: Increased fat mass is becoming more prevalent in women and its accumulation in the abdominal region can lead to numerous health risks such as diabetes mellitus. The clay body wrap using compounds such as green clay, green tea and magnesium sulfate, in addition to microcurrent, may reduce abdominal fat mass and minimize or prevent numerous health problems. Objective: This study aims at measuring the influence of the clay body wrap with microcurrent and aerobic exercise on abdom...

  12. Assessment of radiological hazards of clay bricks fabricated in the Punjab province of Pakistan

    International Nuclear Information System (INIS)

    The Punjab is the most populous among the four provinces of Pakistan, which has around 72 million of people and 205 344 km2 of land. The majority of the population of this province lives in houses made of clay bricks that contain variable amounts of naturally occurring radioactive material (NORM). The concentration level of NORM in clay bricks used to construct dwellings may pose health hazards to inhabitants if it exceeds the permissible limits. For radiological surveillance, activity concentrations of the primordial radionuclides 40K, 226Ra and 232Th were measured in 140 brick samples collected from 35 districts of the Punjab province. A high-purity germanium gamma-ray detector coupled with a personal computer-based multichannel analyzer was employed for the measurement of activity concentrations of primordial radionuclides in the brick samples. The province-wide average activity concentrations and the range (given in parenthesis) of 40K, 226Ra and 232Th were found to be 624 ± 133 (299-918), 35 ± 7 (21-47) and 42 ± 8 (22-58) Bq kg-1, respectively. The values lie within the range of activity concentration values for clay bricks of some countries of Asia. Potential radiological constraint was checked in the form of hazard indices calculated from the measured activity concentrations; the indices were found to be less than their limiting values. Indoor external dose was calculated for a standard size room made of clay bricks, and the dose rate was 159 ± 30 (83-219) nGy h-1. The average value of the dose rate is comparable to that of Asian countries and is about twice the worldwide average value. Annual effective dose Eff in the bricks-made room was calculated and the average value of the dose was 0.80 mSv y-1, which is about twice the worldwide background value of 0.41 mSv y-1. (authors)

  13. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    Science.gov (United States)

    Longo, Simona; Mauro, Marco; Daniel, Christophe; Galimberti, Maurizio; Guerra, Gaetano

    2013-11-01

    Supercritical carbon dioxide (scCO2) treatments of a montmorillonite (MMT) intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT) led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS), have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals.

  14. 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

  15. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    GaetanoGuerra

    2013-11-01

    Full Text Available Supercritical carbon dioxide (scCO2 treatments of a montmorillonite (MMT intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS, have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals.

  16. Quantifying the effect of squirt flow dispersion from compliant clay porosity in clay bearing sandstones

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    Compliant porosity in the form of cracks is known to cause significant attenuation and velocity dispersion through pore pressure gradients and consequent relaxation, dubbed squirt flow. Squirt flow from cracks vanish at high confining stress due to crack closing. Studies on clay bearing sandstones...

  17. The use of clays as sorbents and catalysts

    International Nuclear Information System (INIS)

    The paper attempts to show the structural, physical and chemical properties of clay minerals relate to their laboratory, industrial and environmental uses as sorbents and catalysts. A brief review of the formulae and structures of clays and their relationship to their chemical and physical properties follows. Clay minerals are also useful in environmental protection as they can adsorb crude oils from spills and they are used, sometimes mixed into concrete, as containment barriers for radionuclides caesium 137 and strontium 90. Clay soils can also act as natural barriers to the migration of radionuclides in the environment

  18. Synthesis and Characterization of Epoxy/Clay Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Seo, Dong Il; Lee, Jae Rock [Advanced Materials Division, Korea Research Institute of Chemical Technology, Taejon (Korea); Kim, Dae Su [School of Chemical Engineering, Chungbuk National University, Chongju (Korea)

    2001-04-01

    In this work, one of the smectitic clay, montmorillonite, was organically modified with dodecylammonium chloride to prepare the polymer/clay nanocomposites by melt intercalation. After DGEBA (diglycidyl ether of bisphenol A)/clay nanocomposites has been mixed with weight percent of clay, it was synthesized by heating the mixture to the exfoliation temperature at a heating rate of 10 degree C/min. X-ray diffraction (XRD) showed that the silicate interlayer of organically modified clay increased about 8 AA. No significant change in silicate interlayer of nanocomposites was observed with the increased clay content. The silicate interlayer of nanocomposites contained a uniform dispersion of exfoliated clay layers. Differential scanning calorimeter (DSC) showed that two exothermic processes occurred during the reaction. The lower temperature process was attributed to polymerization of pre-intercalated epoxide on the internal surfaces. Polymerization of the extragallery monomer on the external and internal surfaces of the clay particles occurred at the higher temperature. Thermal stability coefficient was increased with increasing the clay content as indicated by thermogravimetric analysis (TGA). 30 refs., 7 figs., 2 tabs.

  19. Water diffusion in clays with added organic surfactants

    International Nuclear Information System (INIS)

    Tensoactive agents may decrease water absorption in clay products like adobes. They modify the characteristics of the surface of clay particles. Characterization of water diffusion through the pores of modified clays is important to apply appropriate surface modifiers and to improve their performance. We established a simple model for water diffusion in test samples of defined dimensions to estimate real physical parameters and their effect on water absorption. Adsorption mechanisms are examined based on experimental results. The fitting of the experimental data to the model provides a deep understanding of water adsorption in chemically modified clays. A better agreement between the model and the experimental data is achieved for complex molecules

  20. Optimization method for quantitative calculation of clay minerals in soil

    Indian Academy of Sciences (India)

    Libo Hao; Qiaoqiao Wei; Yuyan Zhao; Zilong Lu; Xinyun Zhao

    2015-04-01

    Determination of types and amounts for clay minerals in soil are important in environmental, agricultural, and geological investigations. Many reliable methods have been established to identify clay mineral types. However, no reliable method for quantitative analysis of clay minerals has been established so far. In this study, an attempt was made to propose an optimization method for the quantitative determination of clay minerals in soil based on bulk chemical composition data. The fundamental principles and processes of the calculation are elucidated. Some samples were used for reliability verification of the method and the results prove the simplicity and efficacy of the approach.

  1. A clay grouting technique for granitic rock adjacent to clay bulkhead

    Energy Technology Data Exchange (ETDEWEB)

    Masumoto, K. [Kajima Technical Research Institute (Japan); Sugita, Y.; Fujita, T. [Japan Nuclear Cycle Development Institute, JNC (Japan); Martino, J.B.; Kozak, E.T.; Dixon, D.A. [Atomic Energy of Canada Limited (AECL) (Japan)

    2005-07-01

    A major international experiment, the Tunnel Sealing Experiment (TSX), demonstrating technologies for tunnel sealing at full-scale, was conducted at Canada's Underground Research Laboratory (URL) in the granitic rock. Two bulkheads were installed; one consisted of high-performance concrete and the other of highly compacted sand-bentonite material. The performance of these two bulkheads was monitored throughout the experiment in order to evaluate the influence of elevated hydraulic head (4 MPa) and chamber temperature (up to 85 C) on these materials. The TSX tunnel was excavated by controlled drilling, and blasting techniques in a highly stressed granite rock mass. The excavation technique and re-distribution of in-situ stress around the TSX tunnel lead to the development of an excavation damage zone (EDZ) of variable extent. Both bulkheads were keyed into the rock wall of the tunnel. The keys were excavated with a mechanical technique using line drilling and perimeter reaming to isolate blocks of rock and rock splitters to break out those blocks. The keys were designed to act as cut-off for the EDZ of the main tunnel. The shape of the keys was selected with the assist of numerical models that indicate the key shapes selected should provide a gap in the EDZ. As an additional measure to interrupt the connectivity of EDZ at the bulkhead, clay grouting was conducted around the clay bulkhead. A clay grouting is effective method to reduce the permeability of fractured rock, but grouting into the EDZ is difficult because many of the fractures in the EDZ are connected with the excavation surface and cannot be filled efficiently by pressurizing the grout slurry. Therefore, the injection boreholes were drilled with shallow inclinations from the wall of the tunnel to allow the boreholes to intersect the EDZ for a longer distance. The grouting technique involved injecting a series of successively thicker bentonite slurries from 0,2%, 0,5%, 1,0%, 2,0%, 4,0%, 6,0% to 8

  2. A clay grouting technique for granitic rock adjacent to clay bulkhead

    International Nuclear Information System (INIS)

    A major international experiment, the Tunnel Sealing Experiment (TSX), demonstrating technologies for tunnel sealing at full-scale, was conducted at Canada's Underground Research Laboratory (URL) in the granitic rock. Two bulkheads were installed; one consisted of high-performance concrete and the other of highly compacted sand-bentonite material. The performance of these two bulkheads was monitored throughout the experiment in order to evaluate the influence of elevated hydraulic head (4 MPa) and chamber temperature (up to 85 C) on these materials. The TSX tunnel was excavated by controlled drilling, and blasting techniques in a highly stressed granite rock mass. The excavation technique and re-distribution of in-situ stress around the TSX tunnel lead to the development of an excavation damage zone (EDZ) of variable extent. Both bulkheads were keyed into the rock wall of the tunnel. The keys were excavated with a mechanical technique using line drilling and perimeter reaming to isolate blocks of rock and rock splitters to break out those blocks. The keys were designed to act as cut-off for the EDZ of the main tunnel. The shape of the keys was selected with the assist of numerical models that indicate the key shapes selected should provide a gap in the EDZ. As an additional measure to interrupt the connectivity of EDZ at the bulkhead, clay grouting was conducted around the clay bulkhead. A clay grouting is effective method to reduce the permeability of fractured rock, but grouting into the EDZ is difficult because many of the fractures in the EDZ are connected with the excavation surface and cannot be filled efficiently by pressurizing the grout slurry. Therefore, the injection boreholes were drilled with shallow inclinations from the wall of the tunnel to allow the boreholes to intersect the EDZ for a longer distance. The grouting technique involved injecting a series of successively thicker bentonite slurries from 0,2%, 0,5%, 1,0%, 2,0%, 4,0%, 6,0% to 8,0%. The

  3. 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

  4. 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

  5. Geosynthetic clay liners - slope stability field study

    International Nuclear Information System (INIS)

    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project

  6. Geosynthetic clay liners - slope stability field study

    Energy Technology Data Exchange (ETDEWEB)

    Carson, D.A. [Environmental Protection Agency, Cincinnati, OH (United States); Daniel, D.E. [Univ. of Illinois, Urbana, IL (United States); Koerner, R.M. [Geosynthetic Research Institute, Philadelphia, PA (United States); Bonaparte, R. [GeoSyntec Consultants, Atlanta, GA (United States)

    1997-12-31

    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project.

  7. Geotechnical and mineralological Konyaalti (Antalya, Turkey) clays

    International Nuclear Information System (INIS)

    Geotechnical and mineralogical characteristics of blue-green clays of the Harbour District existing inside the boundaries of Antalya Konyaalti Municipality were investigated with comprehensive field and laboratory tests. Today, building construction in this district is carried out without any prior qualified geotechnical investigations taking place. Undisturbed and disturbed soil specimens were taken from 12 drilled boreholes at 1.5 m intervals and down 30 m deep. Shelby tubes samples were retrieved and SPT were carried out in order to determine soil profile and geotechnical properties. After comparing the laboratory and field test results, it was observed that they were in agreement. Strength and compressibility characteristics of the soil were defined with the correlations using laboratory and field test results. Since the region has been formed of lagoon-sedimented clays, rock analysis was done on two specimens achieved from various depths along the soil profile. XRD analyses on eleven specimens were also conducted. Unconfined compressive strength (qu), undrained cohesion (Cu) and compression index (Cc) varies between 40 kN/m2, 7.0 kN/m2 and 90 kN/m2, 0.095 and 0.38, respectively. (author)

  8. Can clays ensure nuclear waste repositories?

    Science.gov (United States)

    Zaoui, A.; Sekkal, W.

    2015-03-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation.

  9. 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

  10. Can clays ensure nuclear waste repositories?

    Science.gov (United States)

    Zaoui, A; Sekkal, W

    2015-01-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation. PMID:25742950

  11. A structural analysis model for clay caps

    International Nuclear Information System (INIS)

    This paper presents a structural analysis model for clay caps used in the landfill of low-level nuclear waste to minimize the migration of fluid through the soil. The clay cap resting on the soil foundation is treated as an axially symmetric elastic plate supported by an elastic foundation. A circular hole (concentric with the plate) in the elastic foundation represents an underlying cavity formed in the landfill due to waste decomposition and volume reduction. Unlike the models that commonly represent the soil foundation with equivalent springs, this model treats the foundation as a semi-infinite space and accounts for the work done by both compression and shear stresses in the foundation. The governing equation of the plate is based upon the classical theory of plate bending, whereas the governing equation derived by using Vlasov's general variational method describes the soil foundation. The solutions are expressed in terms of Basset functions. A FORTRAN program was written to carry out the numerical calculations

  12. Obtention of chemically modified clays: organovermiculites

    International Nuclear Information System (INIS)

    The organovermiculite is obtained by incorporating the quaternary ammonium salt in the clay mineral vermiculite interlayer space. The objective of this work was to prepare organovermiculites for applications in organic contaminants adsorption. The variation of interlayer space was determined when the vermiculite was treated with an ionic salt (Praepagem WB) and a non-ionic salt (Amina Etoxilada TA50) in different concentrations. Before interacting with quaternary ammonium salt, the clay mineral was subjected to cationic change process with Na2CO3 to substitute Mg2+ by Na+. The results showed enlargement of interlayer space, reaching values up to 60.0 Å. The vermiculite pre-activated with Na2CO3 during 5 days and modified with the Praepagem WB showed the best performance. Amina Etoxilada TA50 salt was not observed significant changes with increasing concentration. The affinity of organovermiculite for organic solvents was confirmed by Foster swelling test and the best results were observed with diesel and petrol as solvents. (author)

  13. Visual characteristics of clay target shooters.

    Science.gov (United States)

    Abernethy, B; Neal, R J

    1999-03-01

    A comprehensive battery of standardised visual tests was administered to 11 skilled and 12 novice clay target shooters in an attempt to determine the distinctive visual characteristics of expert performers in this sport. The static and dynamic visual acuity, ocular muscle balance, ocular dominance, depth perception and colour vision of each of the subjects was measured in addition to their performance on simple and choice reaction time, peripheral response time, rapid tachistoscopic detection, coincidence timing and eye movement skills tasks. Expert superiority was observed on the simple reaction time measure only, and the novices actually outperformed the skilled subjects on a number of the other visual measures (viz., static acuity at near distance, dynamic acuity, vertical ocular muscle balance, choice reaction time and rapid target detection discriminability). Scores on all measures for both groups were within the expected normal range indicating that normal and not necessarily above-average basic visual functioning is sufficient to support skilled clay target shooting. An important implication of the finding that skilled shooters are not characterised by supranormal levels of basic visual functioning is the recognition that any attempt to improve shooting performance through training of general attributes of vision to supranormal levels is likely to be unproductive. PMID:10331472

  14. Impact-Induced Clay Mineral Formation and Distribution on Mars

    Science.gov (United States)

    Rivera-Valentin, E. G.; Craig, P. I.

    2015-01-01

    Clay minerals have been identified in the central peaks and ejecta blankets of impact craters on Mars. Several studies have suggested these clay minerals formed as a result of impact induced hydrothermalism either during Mars' Noachian era or more recently by the melting of subsurface ice. Examples of post-impact clay formation is found in several locations on Earth such as the Mjolnir and Woodleigh Impact Structures. Additionally, a recent study has suggested the clay minerals observed on Ceres are the result of impact-induced hydrothermal processes. Such processes may have occurred on Mars, possibly during the Noachian. Distinguishing between clay minerals formed preor post-impact can be accomplished by studying their IR spectra. In fact, showed that the IR spectra of clay minerals is greatly affected at longer wavelengths (i.e. mid-IR, 5-25 micron) by impact-induced shock deformation while the near-IR spectra (1.0-2.5 micron) remains relatively unchanged. This explains the discrepancy between NIR and MIR observations of clay minerals in martian impact craters noted. Thus, it allows us to determine whether a clay mineral formed from impact-induced hydrothermalism or were pre-existing and were altered by the impact. Here we study the role of impacts on the formation and distribution of clay minerals on Mars via a fully 3-D Monte Carlo cratering model, including impact- melt production using results from modern hydrocode simulations. We identify regions that are conducive to clay formation and the location of clay minerals post-bombardment.

  15. 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

  16. Corrosion behaviour of carbon steel in the Tournemire clay

    International Nuclear Information System (INIS)

    Carbon steels are possible materials for the fabrication of nuclear waste containers for long term geological disposal in argillaceous environments. Experimental studies of the corrosion behaviour of such materials has been conducted in various conditions. Concerning the numerous laboratory experiments, these conditions (water and clay mixture or compacted clay) mainly concern the bentonite clay that would be used for the engineered barrier. On the opposite, only few in-situ experiments has been conducted directly in the local clay of the repository site (such as Boom clay, etc.). In order to better estimate the corrosion behaviour of carbon steels in natural clay site conditions, an experimental study has been conducted jointly by EDF and IRSN in the argillaceous French site of Tournemire. In this study, A42 carbon steel specimens have been exposed in 3 different zones of the Tournemire clay formation. The first type of environmental conditions concerns a zone where the clay has not been affected by the excavation (EDZ) of the main tunnel neither by the main fracture zone of the clay formation. The second and third ones are located in the EDZ of the tunnel. In the second zone, an additional aerated water flows from the tunnel, whereas it does not in the third place. Some carbon steel specimens have been extracted after several years of exposure to these conditions. The average corrosion rate has been measured by the weight loss technique and the pitting corrosion depth has been evaluated under an optical microscope. Corrosion products have also been characterised by scanning electron microscopy and X-ray diffraction technique. Results are then discussed regarding the surrounding environmental conditions. Calculations of the oxygen transport from the tunnel through the clay and of the clay re-saturation can explain, in a first approach, the corrosion behaviour of the carbon steel in the different tested zones. (authors)

  17. 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

  18. Annual Interviews

    CERN Multimedia

    Human Resources Department

    2005-01-01

    Annex II, page 1, Section 3 of the Administrative Circular no. 26 (Rev. 5) states that "The annual interview shall usually take place between 15 November of the reference year and 15 February of the following year." Following the meeting of the Executive Board on 7 December 2004 and the meeting of the Standing Concertation Committee on 19 January 2005, it has been decided, for the advancement exercise of 2005, to extend this period until 15 March 2005. Human Resources Department Tel. 73566

  19. Water Retention Curves of Opalinus Clay

    International Nuclear Information System (INIS)

    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

  20. 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

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

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Kaam-Peters, H.M.E. van; Koster, J.; Gaast, S. J. van der; Dekker, M.H.A.; Leeuw, J.W. de

    1998-01-01

    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

  2. Alteration of swelling clay minerals by acid activation

    NARCIS (Netherlands)

    Steudel, A.; Batenburg, L.F.; Fischer, H.R.; Weidler, P.G.; Emmerich, K.

    2009-01-01

    The bulk material of six dioctahedral and two trioctahedral swellable clay minerals was leached in H2SO4 and HCl at concentrations of 1.0, 5.0 and 10.0 M at 80 °C for several hours. Alteration of the clay mineral structures was dependent on the individual character of each mineral (chemical composit

  3. 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)

  4. Calcination of kaolinite clay particles for cement production

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse;

    2014-01-01

    Kaolinite rich clay particles calcined under certain conditions can attain favorable pozzolanic properties and can be used to substitute part of the CO2 intensive clinker in cement production. To better guide calcination of a clay material, a transient one-dimensional single particle model...

  5. Centrifuge modelling of rigid piles in soft clay

    DEFF Research Database (Denmark)

    Klinkvort, R.T.; Poder, M.; Truong, P.;

    2016-01-01

    this study is to employ centrifuge modelling in order to derive experimental p-y curves for rigid piles embedded in over-consolidated soft clay. A kaolin clay sample was prepared and pre-consolidated by applying a constant pressure at the soil surface, while different over-consolidation ratios were...

  6. 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.

  7. Adsorption of hydrogen gas and redox processes in clays

    International Nuclear Information System (INIS)

    In order to assess the adsorption properties of hydrogen gas and reactivity of adsorbed hydrogen, we measured H2(g) adsorption on Na synthetic montmorillonite-type clays and Callovo-Oxfordian (COx) clay-rock using gas chromatography. Synthetic montmorillonites with increasing structural Fe(III) substitution (0 wt %, 3.2 wt %, and 6.4 wt % Fe) were used. Fe in the synthetic montmorillonites is principally present as structural Fe(III) ions. We studied the concomitant reduction of structural Fe(III) in the clays using 57Fe Moessbauer spectrometry. The COx, which mainly contains smectite/illite and calcite minerals, is also studied together with the pure clay fraction of this clay-rock. Experiments were performed with dry clay samples which were reacted with hydrogen gas at 90 and 120 degrees C for 30 to 45 days at a hydrogen partial pressure close to 0.45 bar. Results indicate that up to 0.11 wt % of hydrogen is adsorbed on the clays at 90 degrees C under 0.45 bar of relative pressure. Fe-57 Moessbauer spectrometry shows that up to 6% of the total structural Fe(III) initially present in these synthetic clays is reduced upon adsorption of hydrogen gas. No reduction is observed with the COx sample in the present experimental conditions. (authors)

  8. Relationship between elastic moduli and pore radius in clay aggregates

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    2011-01-01

    Available experimental data on elastic velocities of clay-air mixtures and clay-brine mixtures as a function of porosity are re-interpreted. Pore radius as calculated from porosity and specific surface measured by BET seems to be the factor controlling stiffness of these un-cemented sediments. For...

  9. 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.

  10. 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

  11. Learning of Cross-Sectional Anatomy Using Clay Models

    Science.gov (United States)

    Oh, Chang-Seok; Kim, Ji-Young; Choe, Yeon Hyeon

    2009-01-01

    We incorporated clay modeling into gross anatomy and neuro-anatomy courses to help students understand cross-sectional anatomy. By making clay models, cutting them and comparing cut surfaces to CT and MR images, students learned how cross-sectional two-dimensional images were created from three-dimensional structure of human organs. Most students…

  12. Differences in physical properties of two clay soils

    OpenAIRE

    Alakukku, Laura; Ristolainen, Antti; nuutinen, Visa

    2008-01-01

    We studied the physical properties of two clay soils (J1 and J2) having relatively similar texture but differing cultivation properties J2 being more sensitive to dry and wet conditions. The general assumption that the productivity of heavy clay soils is mainly threatened by excessive wetness holds in both fields.

  13. 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...

  14. Recovery of Porosity and Permeability for High Plasticity Clays

    DEFF Research Database (Denmark)

    Krogsbøll, Anette; Foged, Niels Nielsen

    Clays, which have been loaded to a high stress level, will under certain conditions keep low porosity and permeability due to the high degree of compression. In some situations it seems that porosity and permeability will recover to a very high extent when the clay is unloaded. This seems to be the...

  15. Large Strain Analysis of Electro-Osmosis Consolidation for Clays

    NARCIS (Netherlands)

    Yuan, J.

    2015-01-01

    Consolidation of soft clay creates a lot of problems in foundation engineering, because of the very low clay permeability and high compressibility. Primary consolidation takes a long time to complete if the material is left consolidating under atmospheric evaporation, and traditional dewatering tech

  16. Free volume sizes in intercalated polyamide 6/clay nanocomposites

    DEFF Research Database (Denmark)

    Wiinberg, P.; Eldrup, Morten Mostgaard; Pedersen, N.J.;

    2005-01-01

    mechanical analysis. At low concentrations of clay the fraction of PA6 crystals melting close to 212 degrees C was increased, while the fraction of the a-form PA6 crystals, melting close to 222 degrees C, was reduced. At higher concentrations of clay, a crystal phase with increased thermal stability emerged...

  17. Study on leaching of refractory uranium in clay

    International Nuclear Information System (INIS)

    The leaching characteristcs of uranium-bearing clay of deposit A and other uranium deposits ar described. The causes of leaching refractoriness of the uranium in clay have been discussed. The research results show that the reason of leaching refractoriness of the uranium in clay is associated with recryctallization of clay minerals (including opel and goethite) during metamorphism of rocks. The probable course of forming refractory uranium in clay may be: adsorption of U+6 by clay minerals; reduction of U+6 to U+4; recrystalization of the clay mineral and U+4 exists at closed or semi-closed state in it. The results show that in order to leach the refractory uranium in clay, the uranium-bearing mineral should be made to produce new faultiness for reopening the passages into the mineral, thereby the uranium existing at closed or semi-closed state is exposed, and at the same time U+4 is oxidized to U+6. The middle-low temperature oxidation roasting, pressure alkaline leaching (160-180 deg C), and leaching with concentrated acid are efficient in treating the refractory type uranium ore

  18. Charge Properties and Clay Mineral Composition of Tianbao Mountains Soils

    Institute of Scientific and Technical Information of China (English)

    HEJI-ZHENG; LIXUE-YUAN; 等

    1992-01-01

    The clay mineral association,oxides of clay fraction and surface charge properties of 7 soils,which are developed from granite,located at different altitudesof the Tianbao Mountains were studied.Results indicate that with the increase in altitude,1) the weathering process and desilicification of soil clay minerals became weaker,whereas the leaching depotassication and the formation process of hydroxy-aluminum interlayer got stronger;2)the contents of amorphous and complex aluminum and iron,and the activity of aluminum and iron oxides for soil clay fraction increased;and 3) the amount of variable negarive charge,anion exchange capacity and the values of PZC and PZNC also increased.The activity of aluminum and iron oxides,the accumulation of aluminum,and surface charge characteristics and their relation to clay oxides of the vertical zone soils were observed and recorded.

  19. Nanocomposites of PP and bentonite clay modified with different surfactants

    International Nuclear Information System (INIS)

    The aim of this work was the development of nano composites of polypropylene (PP) and national bentonite clay modified with different surfactants. The results of X-Ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) showed that the organophilization process was effective. The surfactants led to a significant increase in the basal spacing of Brasgel PA clay. XRD results of the mixture PP/Brasgel PA clay modified with Praepagem WB surfactant indicated that a nanocomposite with intercalated structure was formed. When the Brasgel PA clay was modified with Praepagem HY surfactant, DRX results indicated that a micro composite was formed. Screw speed, clay content and PP viscosity had no influence on the XRD pattern of the obtained materials. (author)

  20. 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)

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

    International Nuclear Information System (INIS)

    Andra organised an International Symposium on the use of Natural and Engineered Clay-based Barriers for the Containment of Radioactive Waste hold at the Congress Centre of Tours, France, in March 2005. The symposium provided an opportunity to take stock of the potential properties of the clay-based materials present in engineered or natural barriers in order to meet the containment specifications of a deep geological repository for radioactive waste. It was intended for specialists working in the various disciplines involved with clays and clay based minerals, as well as scientists from agencies and organisations dealing with investigations on the disposal of high-level and long-lived radioactive waste. The themes of the Symposium included geology, geochemistry, transfers of materials, alteration processes, geomechanics, as well as the recent developments regarding the characterisation of clays, as well as experiments in surface and underground laboratories. The symposium consisted of plenary sessions, parallel specialized sessions and poster sessions. (author)

  2. Synthesis and characterization of novel chromium pillared clays

    International Nuclear Information System (INIS)

    New chromium pillared clays of basal spacing 2.45 nm were synthesized and characterized. The chromium oligomers used for intercalation were prepared by quick addition of base and acid to Cr(III) monomeric solutions followed by reflux. The synthesized clays exhibit increased BET surface area and higher micropore volume compared to clays with lower galleries, pillared either by smaller Cr(III) oligomers or by Cr(III) monomers. Important parameters affecting the d001 basal spacing were studied, e.g. the pH of the pillaring solution, the intercalation time, the chromium concentration and the counter-anion present in the chromium solutions. Scanning electron micrographs were acquired to demonstrate changes of the clay texture before and after pillaring. The thermal behavior of the synthesized clays was also examined

  3. Mechanical properties of nylon 6/Brazilian clay nanocomposites

    International Nuclear Information System (INIS)

    In this work, nanocomposites of nylon 6 with montmorillonite clay, untreated and treated with two different quaternary ammonium salts (Dodigen and Genamin) were obtained. The originality of this work is that the study includes the Brazilian clay, different clay treatments and the comparison of the results from mechanical properties and X-ray diffraction of nanocomposites. The results indicated that the quaternary ammonium salts were intercalated between the layers of clay, causing an expansion of the interlayer spacing. The obtained nanocomposites showed better mechanical properties when compared to nylon 6. Apparently the treated and untreated clay were compatible with the polymer matrix and presented an exfoliated nanocomposite structure. So, the nanocomposites showed an increase in tensile modulus and yield strength and a decrease in elongation.

  4. Mapping and Quantifying Surface Charges on Clay Nanoparticles.

    Science.gov (United States)

    Liu, Jun; Gaikwad, Ravi; Hande, Aharnish; Das, Siddhartha; Thundat, Thomas

    2015-09-29

    Understanding the electrical properties of clay nanoparticles is very important since they play a crucial role in every aspect of oil sands processing, from bitumen extraction to sedimentation in mature fine tailings (MFT). Here, we report the direct mapping and quantification of surface charges on clay nanoparticles using Kelvin probe force microscopy (KPFM) and electrostatic force microscopy (EFM). The morphology of clean kaolinite clay nanoparticles shows a layered structure, while the corresponding surface potential map shows a layer-dependent charge distribution. More importantly, a surface charge density of 25 nC/cm(2) was estimated for clean kaolinite layers by using EFM measurements. On the other hand, the EFM measurements show that the clay particles obtained from the tailings demonstrate a reduced surface charge density of 7 nC/cm(2), which may be possibly attributed to the presence of various bituminous compounds residing on the clay surfaces. PMID:26352908

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Andra organised an International Symposium on the use of Natural and Engineered Clay-based Barriers for the Containment of Radioactive Waste hold at the Congress Centre of Tours, France, in March 2005. The symposium provided an opportunity to take stock of the potential properties of the clay-based materials present in engineered or natural barriers in order to meet the containment specifications of a deep geological repository for radioactive waste. It was intended for specialists working in the various disciplines involved with clays and clay based minerals, as well as scientists from agencies and organisations dealing with investigations on the disposal of high-level and long-lived radioactive waste. The themes of the Symposium included geology, geochemistry, transfers of materials, alteration processes, geomechanics, as well as the recent developments regarding the characterisation of clays, as well as experiments in surface and underground laboratories. The symposium consisted of plenary sessions, parallel specialized sessions and poster sessions. (author)

  6. 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.

  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. Organic/Inorganic Hybrid Polymer/Clay Nanocomposites

    Science.gov (United States)

    Park, Cheol; Connell, John W.; Smith, Joseph G., Jr.

    2003-01-01

    A novel class of polymer/clay nanocomposites has been invented in an attempt to develop transparent, lightweight, durable materials for a variety of aerospace applications. As their name suggests, polymer/ clay nanocomposites comprise organic/ inorganic hybrid polymer matrices containing platelet-shaped clay particles that have sizes of the order of a few nanometers thick and several hundred nanometers long. Partly because of their high aspect ratios and high surface areas, the clay particles, if properly dispersed in the polymer matrix at a loading level of 1 to 5 weight percent, impart unique combinations of physical and chemical properties that make these nanocomposites attractive for making films and coatings for a variety of industrial applications. Relative to the unmodified polymer, the polymer/ clay nanocomposites may exhibit improvements in strength, modulus, and toughness; tear, radiation, and fire resistance; and lower thermal expansion and permeability to gases while retaining a high degree of optical transparency.

  9. Some considerations on a borehole in a clay formation

    International Nuclear Information System (INIS)

    A borehole has been drilled in the clay formation underlying the Trisaia Nuclear Research Center (CNEN) in Southern Italy. The local stratigraphic series includes 850 m of marly clay of Pliocene-Calabrian age. The drilling operation has been interrupted at about -400 m, due to the occurrence of methane gas. The presence of gas, the reducing conditions of the clay and the lack of water in fracture zones testify the extremely low permeability of this clay formation. Reducing conditions may prevent the migration of many radionuclides. The occurrence of some sandy levels and lenses is due to the coastal character of the paleosedimentary environment. Previsions on the homogeneity of clay bodies may be indirectly inferred by examination of feeder paleobasins

  10. Decantation time of evaluation on bentonite clays fractionation

    International Nuclear Information System (INIS)

    Bentonite clays present a great number of industrial uses, from petroleum to pharmaceutics and cosmetic industry. The bentonite clay present particles with very fine particles that is responsible by the vast application of these materials. However, commercial clays present wide particle size distribution and a significant content of impurities, particularly quartz, in the form of silt and fine silt. So, the aim of this work is to analyze the effect of the stirring and decantation time in the deagglomeration, purification and size separation of the bentonite clay particles from Paraiba. The clays were characterized by X-ray diffraction and particle size distribution. Based on the results it was observed the decantation time give the elimination of the agglomerates formed by submicrometric particles. The uses of decantation column give separation of the fraction below 200nm. (author)

  11. Sorption Energy Maps of Clay Mineral Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cygan, Randall T.; Kirkpatrick, R. James

    1999-07-19

    A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation.

  12. Composites Based on Fly Ash and Clay

    International Nuclear Information System (INIS)

    Fly ash is a waste generated from the coal combustion during the production of electricity in the thermal power plants. It presents industrial by-product containing Technologically Enhanced Natural Occurring Radioactive Materials (TENORM) with the great potential for valorisation. Fly ash is successfully utilized in cement and concrete industry, also in ceramics industry as component for manufacturing bricks and tiles, and recently there are many investigations for production of glass-ceramics from fly ash. Although the utilization of fly ash in construction and civil engineering is dominant, the development of new alternative application for its further exploitation into new products is needed. This work presents the possibility for fly ash utilization for fabricating dense composites based on clay and fly ash with the potential to be used in construction industry

  13. STABILISATION OF SILTY CLAY SOIL USING CHLORIDE

    Directory of Open Access Journals (Sweden)

    TAMADHER T. ABOOD

    2007-04-01

    Full Text Available The object of this paper is to investigate the effect of adding different chloride compounds including (NaCl, MgCl2, CaCl2 on the engineering properties of silty clay soil. Various amounts of salts (2%, 4%, and 8% were added to the soil to study the effect of salts on the compaction characteristics, consistency limits and compressive strength. The main findings of this study were that the increase in the percentage of each of the chloride compounds increased the maximum dry density and decrease the optimum moisture content. The liquid limit, plastic limit and plasticity index decreased with the increase in salt content. The unconfinedcompressive strength increased as the salt content increased.

  14. Directional plasticity of clay showing instability

    International Nuclear Information System (INIS)

    A graphical approach is used to sketch the field of small plastic strains (ε < 0.1 %) of Pisa clay along different axi-symmetric stress paths associated to a partial confining stress reduction. Within the classic framework of elasto-plasticity, volumetric and deviatoric plastic strains contours are determined from data obtained from triaxial tests, assuming a cross-anisotropic hypo-elastic formulation calibrated on a wide set of tests and with non linear evolution of the elastic moduli calibrated along a quasi-1D swelling stress path. The evolutions of the plastic strains and of the plastic strain vectors are shown along the stress path directly explored with tests and along virtual paths interpolated from the actual data along intermediate directions at various strain levels.

  15. Directional plasticity of clay showing instability

    Science.gov (United States)

    Fortuna, Sonia

    2010-06-01

    A graphical approach is used to sketch the field of small plastic strains (epsilon < 0.1 %) of Pisa clay along different axi-symmetric stress paths associated to a partial confining stress reduction. Within the classic framework of elasto-plasticity, volumetric and deviatoric plastic strains contours are determined from data obtained from triaxial tests, assuming a cross-anisotropic hypo-elastic formulation calibrated on a wide set of tests and with non linear evolution of the elastic moduli calibrated along a quasi-1D swelling stress path. The evolutions of the plastic strains and of the plastic strain vectors are shown along the stress path directly explored with tests and along virtual paths interpolated from the actual data along intermediate directions at various strain levels.

  16. Adsorption of amitraz on the clay

    Directory of Open Access Journals (Sweden)

    Jale Gülen

    2013-01-01

    Full Text Available Amitraz (AZ that is used as acaridies was tried to extract with a clay. The experimental data were modelled as using Langmuir and Freundlich isotherms. The adsorption data fit well with Langmuir isotherm that indicated the AZ adsorption is homogeneous and monolayer. The monolayer adsorption capacity was found to be 35.02 mg/g at 20 ºC temperature. Effect of the phases contact time, the initial solution pH and the initial pesticide concentration were investigated from the point of adsorption equilibrium and yield. The adsorption kinetics were investigated by applying pseudo first order, pseudo second order and intra particle diffusion laws. Adsorption of AZ was found to be best fitted by the pseudo second order model. The intra particle diffusion also plays an important role in adsorption phenomenon.

  17. Clay/polymer composites: the story

    Directory of Open Access Journals (Sweden)

    Fengge Gao

    2004-11-01

    Full Text Available Clay/polymer nanocomposites offer tremendous improvement in a wide range of physical and engineering properties for polymers with low filler loading. This technology can now be applied commercially and has received great attention in recent years. The major development in this field has been carried out over the last one and half decades. The progress, advantages, limitations, and current problems will be discussed in this review. So far, significant progress has been made in the development of synthetic methods, application to engineering polymers, and the investigation of major engineering properties. However, we are far from the end of the tunnel in terms of understanding the mechanisms of the enhancement effect in nanocomposites.

  18. Sorption Energy Maps of Clay Mineral Surfaces

    International Nuclear Information System (INIS)

    A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation

  19. Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Jiang-Jen Lin

    2010-04-01

    Full Text Available Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 Å (X-ray diffraction as well as hydrophobic property. The inorganic clays of layered structure could be modified by the poly(oxypropyleneamine-salts as the intercalating agents with molecular weights ranging from 230 to 5,000 g/mol. Furthermore, natural montmorillonite (MMT clay could be exfoliated into thin layer silicate platelets (ca. 1 nm thickness in one step by using polymeric types of exfoliating agents. Different lateral dimensions of MMT, synthetic fluorinated Mica and LDH clays had been cured into epoxy nanocomposites. The hydrophobic amine-salt modification resulting in high spacing of layered or exfoliation of individual clay platelets is the most important factor for gaining significant improvements of properties. In particular, these modified clays were reported to gain significant improvements such as reduced coefficient of thermal expansion (CTE, enhanced thermal stability, and hardness. The utilization of these layered clays for initiating the epoxy self-polymerization was also reported to have a unique compatibility between clay and organic resin matrix. However, the matrix domain lacks of covalently bonded crosslink and leads to the isolation of powder material. It is generally concluded that the hydrophobic expansion of the clay inter-gallery spacing is the crucial step for enhancing the compatibility and the ultimate preparation of the advanced epoxy materials.

  20. Fractal dimensions of flocs between clay particles and HAB organisms

    Science.gov (United States)

    Wang, Hongliang; Yu, Zhiming; Cao, Xihua; Song, Xiuxian

    2011-05-01

    The impact of harmful algal blooms (HABs) on public health and related economics have been increasing in many coastal regions of the world. Sedimentation of algal cells through flocculation with clay particles is a promising strategy for controlling HABs. Previous studies found that removal efficiency (RE) was influenced by many factors, including clay type and concentration, algal growth stage, and physiological aspects of HAB cells. To estimate the effect of morphological characteristics of the aggregates on HAB cell removal, fractal dimensions were measured and the RE of three species of HAB organism, Heterosigma akashiwo, Alexandrium tamarense, and Skeletonema costatum, by original clay and modified clay, was determined. For all HAB species, the modified clay had a higher RE than original clay. For the original clay, the two-dimensional fractal dimension ( D 2) was 1.92 and three-dimensional fractal dimension ( D 3) 2.81, while for the modified clay, D 2 was 1.84 and D 3 was 2.50. The addition of polyaluminum chloride (PACl) lead to a decrease of the repulsive barrier between clay particles, and resulted in lower D 2 and D 3. Due to the decrease of D 3, and the increase of the effective sticking coefficient, the flocculation rate between modified clay particles and HAB organisms increased, and thus resulted in a high RE. The fractal dimensions of flocs differed in HAB species with different cell morphologies. For example, Alexandrium tamarense cells are ellipsoidal, and the D 3 and D 2 of flocs were the highest, while for Skeletonema costatum, which has filamentous cells, the D 3 and D 2 of flocs were the lowest.

  1. Fractal dimensions of flocs between clay particles and HAB organisms

    Institute of Scientific and Technical Information of China (English)

    WANG Hongliang; YU Zhiming; CAO Xihua; SONG Xiuxian

    2011-01-01

    The impact of harmful algal blooms (HABs) on public health and related economics have been increasing in many coastal regions of the world. Sedimentation of algal cells through flocculation with clay particles is a promising strategy for controlling HABs. Previous studies found that removal efficiency (RE) was influenced by many factors, including clay type and concentration, algal growth stage,and physiological aspects of HAB cells. To estimate the effect of morphological characteristics of the aggregates on HAB cell removal, fractal dimensions were measured and the RE of three species of HAB organism, Heterosigma akashiwo, Alexandrium tamarense, and Skeletonema costatum, by original clay and modified clay, was determined. For all HAB species, the modified clay had a higher RE than original clay.For the original clay, the two-dimensional fractal dimension (D2) was 1.92 and three-dimensional fractal dimension (D3) 2.81, while for the modified clay, D2 was 1.84 and D3 was 2.50. The addition of polyaluminum chloride (PACI) lead to a decrease of the repulsive barrier between clay particles, and resulted in lower D2 and D3. Due to the decrease of D3, and the increase of the effective sticking coefficient,the flocculation rate between modified clay particles and HAB organisms increased, and thus resulted in a high RE. The fractal dimensions of flocs differed in HAB species with different cell morphologies. For example, Alexandrium tamarense cells are ellipsoidal, and the D3 and D2 of flocs were the highest, while for Skeletonema costatum, which has filamentous cells, the D3 and D2 of flocs were the lowest.

  2. Layer Charge of Clay Minerals; Selected papers from the Symposium on Current Knowledge on the Layer Charge of Clay Minerals

    Science.gov (United States)

    This Special issue contains papers based on the contributions presented during the workshop “Current Knowledge on the Layer Charge of Clay Minerals”, held on September 18 and 19, 2004, in the Smolenice Castle, Slovakia. Layer charge is one of the most important characteristics of clay minerals as it...

  3. The constitution, evaluation and ceramic properties of ball clays Constituição avaliação e propriedades cerâmicas de "ball clays"

    OpenAIRE

    Ian Richard Wilson

    1998-01-01

    Ball clay is a fine-grained highly plastic, mainly kaolinitic, sedimentary clay, the higher grades of which fire to a white or near white colour. The paper will review the origin of the term "Ball Clay" and the location and origins of several deposits with particular emphasis on the mineralogical, physical and rheological properties which make the clays so important in ceramics bodies. Particular attention will be paid to the well known bay clay deposits of Devon and Dorset in southwest Engla...

  4. Studies of clays and clay minerals using x-ray powder diffraction and the Rietveld method

    International Nuclear Information System (INIS)

    The Rietveld method was originally developed (Rietveld, 1967, 1969) to refine crystal structures using neutron powder diffraction data. Since then, the method has been increasingly used with X-ray powder diffraction data, and today it is safe to say that this is the most common application of the method. The method has been applied to numerous natural and synthetic materials, most of which do not usually form crystals large enough for study with single-crystal techniques. It is the ability to study the structures of materials for which sufficiently large single crystals do not exist that makes the method so powerful and popular. It would thus appear that the method is ideal for studying clays and clay minerals. In many cases this is true, but the assumptions implicit in the method and the disordered nature of many clay minerals can limit titsapplicability. This chapter will describe the Rietveld method, emphasizing the assumptions important for the study of disordered materials, and it will outline the potential applications of the method to these minerals. These applications include, in addition to the refinement of crystal structures, quantitative analysis of multicomponent mixtures, analysis of peak broadening, partial structure solution, and refinement of unit-cell parameters

  5. Verification of substitution of bentonites by montmorillonitic clays summary report on Czech montmorillonitic clays

    International Nuclear Information System (INIS)

    Czech bentonites and smectite-rich clays were characterised in order to study if they could be used as buffer and backfill materials instead of non-Czech commercial bentonites. The characterisation work was orgnized by RAWRA (the Czech Radioactive Waste Repository Authority) and the main part of the work was performed in the Czech Republic at Charles University and at Czech Technical University. Parallel and complementary characterisation was conducted in Finland in Sweden. This report was compiled with the aim to summarise the results, and to compare the methods and results gained in different testing laboratories. The characterisation included mineralogical, chemical and geotechnical investigations and experiments on thermal stability and sorption. There were some variations between the results gained in different laboratories. This was mainly due to differences between the testing methods used but also due to heterogeneity of the samples. The Czech bentonite-clays from Rokle and Strance clay deposits contained relatively high amount of swelling minerals and thus can be considered as potential buffer and backfill materials. (orig.)

  6. Studies of clays and clay minerals using x-ray powder diffraction and the Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Bish, D.L.

    1993-09-01

    The Rietveld method was originally developed (Rietveld, 1967, 1969) to refine crystal structures using neutron powder diffraction data. Since then, the method has been increasingly used with X-ray powder diffraction data, and today it is safe to say that this is the most common application of the method. The method has been applied to numerous natural and synthetic materials, most of which do not usually form crystals large enough for study with single-crystal techniques. It is the ability to study the structures of materials for which sufficiently large single crystals do not exist that makes the method so powerful and popular. It would thus appear that the method is ideal for studying clays and clay minerals. In many cases this is true, but the assumptions implicit in the method and the disordered nature of many clay minerals can limit titsapplicability. This chapter will describe the Rietveld method, emphasizing the assumptions important for the study of disordered materials, and it will outline the potential applications of the method to these minerals. These applications include, in addition to the refinement of crystal structures, quantitative analysis of multicomponent mixtures, analysis of peak broadening, partial structure solution, and refinement of unit-cell parameters.

  7. Annual budget

    International Nuclear Information System (INIS)

    This paper reports that all businesses, including individuals, should have a budget - that is, an estimation of income and expense over an annual cycle. For companies, the budget is generally prepared and approved about one quarter before the start of the company's fiscal year and is updated and revised each quarter during the year. Although budgeting is a task dreaded by most exploration managers, it is usually the vehicle by which drilling prospects, the heart of any exploration program, are sold to the final decision makers. The budgeting process should be viewed as an opportunity rather than as a chore to be completed as quickly as possible

  8. Regeneration of Spent Lubricant Refining Clays by Solvent Extraction

    Directory of Open Access Journals (Sweden)

    Yan-zhen Wang

    2015-01-01

    Full Text Available Step-by-step solvent extraction was used to regenerate spent clay by recovering the adsorbed oil in lubricating oil refining clay. Several polar and nonpolar solvents were tested, and petroleum ether (90–120°C and ethanol (95 v% were selected as the nonpolar and polar solvents, respectively. The spent clay was first extracted using petroleum ether (90–120°C to obtain ideal oil and then extracted with a mixed solvent of petroleum ether (90–120°C and ethanol (95 v% two or three times to obtain nonideal oil before being extracted with ethanol and water. Finally, the clay was dried at 130°C to obtain regenerated clay. The total oil recovery can be more than 99 wt% of the adsorbed oil. The recovered ideal oil can be used as lubricating base oil. Shorter storage times for spent clay produce better regeneration results. The regenerated clay can be reused to refine the lubricating base oils.

  9. 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

  10. 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)

  11. 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.

  12. Law of nonlinear flow in saturated clays and radial consolidation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and test ones. Results of experiments show that flow in micro-scale pore of saturated clays follows law of nonlinear flow. Theoretical analyses demonstrate that an interaction of solid-liquid interfaces varies inversely with permeability or porous radius. The interaction is an important reason why nonlinear flow in saturated clays occurs. An exact mathematical model was presented for nonlinear flow in micro-scale pore of saturated clays. Dimension and physical meanings of parameters of it are definite. A new law of nonlinear flow in saturated clays was established. It can describe characteristics of flow curve of the whole process of the nonlinear flow from low hydraulic gradient to high one. Darcy law is a special case of the new law. A mathematical model was presented for consolidation of nonlinear flow in radius direction in saturated clays with constant rate based on the new law of nonlinear flow. Equations of average mass conservation and moving boundary, and formula of excess pore pressure distribution and average degree of consolidation for nonlinear flow in saturated clay were derived by using an idea of viscous boundary layer, a method of steady state in stead of transient state and a method of integral of an equation. Laws of excess pore pressure distribution and changes of average degree of consolidation with time were obtained. Results show that velocity of moving boundary decreases because of the nonlinear flow in saturated clay. The results can provide geology engineering and geotechnical engineering of saturated clay with new scientific bases. Calculations of average degree of consolidation of the Darcy flow are a special case of that of the nonlinear flow.

  13. In situ and laboratory heating experiments in clay rocks

    International Nuclear Information System (INIS)

    An in situ heating experiment has been carried out in an open clay quarry in the area of Monterotondo, near Rome, where large clay deposits outcrop. The main goal of the experiment was to know the temperature field and the thermal effects caused by the high level radioactive waste disposed of in a clayey geological formation. The experiment has been carried out by feeding an electric heater embedded in the clay at 6.4 meters in depth and by measuring temperature increases in boreholes drilled at different distances from the thermal source between 50 and 200 centimeters. After 1,200 hours the heater thermal power was varied from 250 to 500 watt. The theoretical temperature increases in the clay, calculated by means of Belgian MPGST code, have been compared with the experimental results by means of a ''curve fitting'' method which allows the deduction of clay thermal conductivity. The temperature increases measured in the clay fit quite well the theoretical values and show that the clay is a homogeneous and isotropic medium. The main conclusions of the experiment are as follows: the thermal conduction codes are sufficiently accurate to forecast the temperature increases caused in the clay by the dissipation of the heat generated by high level radioactive waste; the thermal conductivity deduced by means of the ''curve fitting'' method ranges from 0.015 to 0.017 W.cm-1.deg.C-1; the temperature variation associated with the transport of clay interstitial water caused by temperature gradient is nearly negligible

  14. Desorption of toluene from modified clays using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    D. G. P. Carneiro

    2004-12-01

    Full Text Available The main objective of this work is to study the regeneration capacity of modified clays using supercritical fluid. These modified clays are used as organic compound adsorvents. The experimental step was done using a packed column with the clay contaminated by toluene. The results obtained showed the influence of the density of the supercritical CO2 and of the organic modifier in the desorption process. These data were modeled with first- and second-order models. Better results were obtained using the second-order model. This study makes possible the scale-up of the desorption process for regeneration of solid matrices using supercritical fluids.

  15. 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)

  16. Processing and characterization of Polystyrene/cornstarch/organophilic clay hybrids

    International Nuclear Information System (INIS)

    Polystyrene/cornstarch composite blends with organophilic Cloisite 15A were prepared in an internal mixer in the presence of maleic anhydride (MA). The contents of clay were 1, 3 and 5%, based on the weight of the blend. The results obtained by X-ray diffraction revealed significant intercalation and exfoliation of clay particles within the polymeric moiety, which indicate increased interaction between the components of the nanocomposites. Thermogravimetric analysis results revealed the increase in thermal stability for the compatibilized blends in relation to the noncompatibilized PS/starch blends. The composites showed better thermal stability with increasing clay content. (author)

  17. Methods for obtention of PS/clay nanocomposites

    International Nuclear Information System (INIS)

    In this work, nanocomposites of Polystyrene (PS) and organoclay were obtained using a twin-screw extruder and a mixer Haake. A commercial clay named Cloisite 20A was used. The clay and the nanocomposites were characterized by X-Ray Diffraction. The rheological properties were investigated carrying out small amplitude oscillatory strain (SAOS). The results of X-ray diffraction showed that the polymer was incorporated by the organoclay. The results of SAOS indicated a better clay dispersion for the samples obtained using the mixer. (author)

  18. Regeneration of Spent Lubricant Refining Clays by Solvent Extraction

    OpenAIRE

    Yan-zhen Wang; Hai-long Xu; Li Gao; Meng-meng Yan; Hong-ling Duan; Chun-min Song

    2015-01-01

    Step-by-step solvent extraction was used to regenerate spent clay by recovering the adsorbed oil in lubricating oil refining clay. Several polar and nonpolar solvents were tested, and petroleum ether (90–120°C) and ethanol (95 v%) were selected as the nonpolar and polar solvents, respectively. The spent clay was first extracted using petroleum ether (90–120°C) to obtain ideal oil and then extracted with a mixed solvent of petroleum ether (90–120°C) and ethanol (95 v%) two or three times to ob...

  19. Radiolysis of carboxylic acids adsorbed in clay minerals

    International Nuclear Information System (INIS)

    This research is aimed at studying the effect of ionizing radiation in an heterogeneous system formed by a carboxylic acid adsorbed in a clay mineral. The study is focussed to discriminate if the presence of a solid surface alters the formation and distribution of radiolytic products in relation to the radiolysis of the carboxylic acid without the surface (clay). The results showed that the radiolysis of the system clay-acid goes along a defined path rather than showing various pathways of decomposition as in the case of simple aqueous solutions. The main pathway was the decarboxylation of the target compound rather than condensation/dimerization reactions

  20. Probabilistic Description of a Clay Site using CPTU tests

    DEFF Research Database (Denmark)

    Andersen, Sarah; Lauridsen, Kristoffer; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    A clay site at the harbour of Aarhus, where numerous cone penetration tests have been conducted, is assessed. The upper part of the soil deposit is disregarded, and only the clay sections are investigated. The thickness of the clay deposit varies from 5 to 6 meters, and is sliced into sections of...... geotechnical assessment of a site, using both the method for classifying soil behaviour types and applying statistics, yield a new level of information, and certainty about the estimates of the strength parameters which are the important outcome of such a site description....

  1. An Experimental Study on the Secondary Deformation of Boom Clay

    OpenAIRE

    Deng, Yongfeng; CUI, Yu-Jun; Tang, Anh Minh; Li, Xiang-Ling; Sillen, Xavier

    2012-01-01

    Boom clay formation, a deposit of slightly over-consolidated marine clay that belongs to the Oligocene series in the north east of Belgium, has been selected as a possible host material of nuclear waste disposal. In this context, the long-term deformation behaviour of Boom clay is of crucial importance in the performance assessment of the whole storage system. In this study, low and high pressure oedometer tests are carried out; the e-log σ'v (void ratio - logarithm of vertical effective stre...

  2. Initial settlements of rock fills on soft clay

    OpenAIRE

    Pedersen, Truls Martens

    2012-01-01

    Rock fills that hit the seabed will remold the underlying material. If this material is a clay with sufficiently low shear strength, it will adopt rheological properties, causing flow through the rock fill, and contributing to the initial settlements of the rock fill in addition to conventional consolidation theory. The settlements of the rocks depend upon the height of the rock fill and how the rocks have been laid out. This is due to the viscosity of the clay, and the fact that clay is thix...

  3. 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.

  4. Identification of the clay body structure by the optical microscope

    OpenAIRE

    Mirtič, Breda; Planjšek, Mojca

    2015-01-01

    Plastic clay is used for manufacturing of the building ceramic. Low amounts of different mineral components are added in order to optimize the manufacturig process and to modify the properties as well as the product image. Results of the investigations of the fired clay bodies are presented in the article. The clay bodies were fired in the oxidation and in the reduction atmosphere at different temperatures. Different amounts of grog, ?$MnO_2$?, ?$TiO_2$?, quartz and fritta were added. Investi...

  5. Strength and Deformation Properties of Tertiary Clay at Moesgaard Museum

    DEFF Research Database (Denmark)

    Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    The tertiary clay at Moesgaard Museum near Aarhus in the eastern part of Jutland in Denmark is a highly plastic, glacially disturbed nappe of Viborg Clay. The clay is characterised as a swelling soil, which could lead to damaging of the building due to additional heave of the soil. To take...... this characteristic, as well as the strength and deformation properties, into account during the design phase, two consolidation tests and one triaxial test have been conducted. This paper evaluates the results of the laboratory tests leading to the preconsolidation stress, the deformation parameters consisting...

  6. Evaluation of red cabbage anthocyanins after partial purification on clay

    Directory of Open Access Journals (Sweden)

    Toni Jefferson Lopes

    2011-12-01

    Full Text Available The aim of this work was to evaluate the red cabbage anthocyanins quality after purification by static adsorption assays on clay (Tonsil Terrana 580FF. Thin-layer chromatography analysis and scan spectrometry on UV-Visible showed a good dye stability of the pigment interacting with the clay. The use of pH 3.0 buffer during the batch assays provided a protective effect on the cabbage anthocyanins, limiting the dye acid hydrolyses. Analyses of the reducing sugars contents of the extract showed that clay retained 20% average of total free sugars under the test conditions.

  7. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Marc in het Panhuis

    2011-04-01

    Full Text Available The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases.

  8. Recycled PET/organo-clay nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Kráčalík, Milan; Studenovský, Martin; Mikešová, Jana; Puffr, Rudolf; Sikora, Antonín; Friedrich, Ch.

    Halle-Wittenberg : Martin Luther University, 2005, SL12.16/1-SL12.16/9. ISBN 3-86010-784-4. [Annual Meeting of Polymer Processing Society /21./. Lepzig (DE), 19.06.2005-23.06.2005] R&D Projects: GA MŽP(CZ) 1C/7/48/04 Institutional research plan: CEZ:AV0Z40500505 Keywords : recycled PET * polymer nanocomposite * montmorillonite Subject RIV: CD - Macromolecular Chemistry

  9. Annual report

    International Nuclear Information System (INIS)

    This is the thirty-ninth annual report of the Atomic Energy Control Board. The period covered by this report is the year ending March 31, 1986. The Atomic Energy Control Board (AECB) was established in 1946, by the Atomic Energy Control Act (AEC Act), (Revised Statues of Canada (R.S.C.) 1970 cA19). It is a departmental corporation (Schedule B) within the meaning and purpose of the Financial Administration Act. The AECB controls the development, application and use of atomic energy in Canada, and participates on behalf of Canada in international measures of control. The AECB is also repsonsible for the administration of the Nuclear Liability Act, (R.S.C. 1970 c29 1st Supp) as amended, including the designation of nuclear installations and the prescription of basic insurance to be carried by the operators of such nuclear installations. The AECB reports to Parliament through a designated Minister, currently the Minister of Energy, Mines and Resources

  10. The potential use of swelling clays for backfilling and sealing of underground repositories: The case of the Boom clay

    International Nuclear Information System (INIS)

    In Belgium the SCK/CEN is studying the geological disposal of high level radioactive waste in the Boom clay formation. In such an argillaceous repository, the backfilling and sealing features will be multiple: boreholes, shafts, access drifts, disposal galleries or holes and dams. A preliminary selection study screening industrial materials has been performed based on the following criteria: at least as good thermal and hydraulic properties as the in situ Boom clay, sufficient volumetric swelling and swelling pressure, proven geochemical compatibility and stability. This study has shown that swelling clays are the most promising materials. Because of its evident geochemical compatibility and its easy availability, it is a logic choice to study the re-use of the excavated clay. The hydraulic, thermal and geochemical retention and swelling properties of the Boom clay were studied and the results are compared to those of bentonites. The main results of this study are: a hydraulic conductivity as low as 10-13 m/s can be reached which is one order of magnitude lower than that of the in situ Boom clay but is one order of magnitude higher than those of bentonite; the volumetric swelling of the Boom clay is rather limited but a swelling pressure of about 4 MPa can be obtained which is about a factor five lower than for bentonites but also corresponds to the in situ lithostatic pressure; the radionuclide retention properties of the in situ Boom clay are at least as good as those of dense bentonites and are for some nuclides even better; steam drastically reduces the volumetric swelling of bentonites which also leads to a higher hydraulic conductivity. The swelling properties of the Boom clay are also to be affected by steam, but the effect is less dramatic. In particular, its low hydraulic conductivity seems to be conserved. (author). 14 refs, 4 figs, 6 tabs

  11. Cobalt 60 cation exchange with mexican clays

    International Nuclear Information System (INIS)

    Mexican clays can be used to remove radioactive elements from contaminated aqueous solutions. Cation exchange experiments were performed with 60 Co radioactive solution. In the present work the effect of contact time on the sorption of Co 2+ was studied. The contact time in hydrated montmorillonite was from 5 to 120 minutes and in dehydrated montmorillonite 5 to 1400 minutes. The Co 2+ uptake value was, in hydrated montmorillonite, between 0.3 to 0.85 m eq/g and in dehydrated montmorillonite, between 0.6 to 1.40 m eq/g. The experiments were done in a pH 5.1 to 5.7 and normal conditions. XRD patterns were used to characterize the samples. The crystallinity was determined by X-ray Diffraction and it was maintained before and after the cation exchange. DTA thermo grams showed the temperatures of the lost humidity and crystallization water. Finally, was observed that dehydrated montmorillonite adsorb more cobalt than hydrated montmorillonite. (Author)

  12. Nitrate Adsorption on Clay Kaolin: Batch Tests

    Directory of Open Access Journals (Sweden)

    Morteza Mohsenipour

    2015-01-01

    Full Text Available Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112.5, 225, and 450 mgNO3-/L, with a constant pH equal to 2, constant temperature equal to 25°C, and exposure period varying from 0 to 150 minutes were considered. The capacity of nitrate adsorption on kaolin has also been studied involving two well-known adsorption isotherm models, namely, Freundlich and Longmuir. The results revealed that approximately 25% of the nitrate present in the solution was adsorbed on clay kaolin. The laboratory experimental data revealed that Freundlich adsorption isotherm model was more accurate than Longmuir adsorption model in predicting of nitrate adsorption. Furthermore, the retardation factor of nitrate pollution in saturated zone has been found to be approximately 4 in presence of kaolin, which indicated that kaolin can be used for natural scavenger of pollution in the environment.

  13. Dynamics of water confined in clay minerals

    International Nuclear Information System (INIS)

    Ultrafast infrared spectroscopy of the O-D stretching mode of dilute HOD in H2O probes the local environment and the hydrogen bond network of confined water. The dynamics of water molecules confined in the interlayer space of montmorillonites (Mt) and in interaction with two types of cations (Li+ and Ca2+) but also with the negatively charged siloxane surface are studied. The results evidence that the OD vibrational dynamics is significantly slowed down in confined media: it goes from 1.7 ps in neat water to 2.6 Ps in the case of Li+ cations with two water pseudo-layers (2.2-2.3 ps in the case of Ca2+ cations) and to 4.7 ps in the case of Li+ cations with one water pseudo-layer. No significant difference between the two cations is noticed. In this 2D confined geometry (the interlayer space being about 0.6 nm for two water pseudo-layers), the relaxation time constants obtained are comparable to the ones measured in analogous concentrated salt solutions. Nevertheless, and in strong opposition to the observations performed in the liquid phase, anisotropy experiments evidence the absence of rotational motions on a 5 ps time scale, proving that the hydrogen bond network in the interlayer space of the clay mineral is locked at this time scale. (authors)

  14. Origin of the high sensitivity of Chinese red clay soils to drought : significance of the clay characteristics

    OpenAIRE

    D'Angelo, Benoît; Bruand, Ary; Qin, Jiangtao; Peng, Xihnua; Hartmann, Christian; Bo, Sun; Hao, Hongtao; Rozenbaum, Olivier; Muller, Fabrice

    2014-01-01

    The red clay soils which are widespread in China are known to be highly sensitive to drought during the dry season but the origin of this high sensitivity to drought remains unclear. Several red clay soils were selected in the Hunan province for study. We studied their basic physico-chemical properties and clay mineralogy, their structure and shrinkage properties, as well as their water retention properties. Results show that the amount of water available between -330 and -15 000 hPa water po...

  15. Characterization of low-purity clays for geopolymer binder formulation

    Institute of Scientific and Technical Information of China (English)

    Nasser Y.Mostafa; Q.Mohsen; A.El-maghraby

    2014-01-01

    The production of geopolymer binders from low-purity clays was investigated. Three low-purity clays were calcined at 750°C for 4 h. The calcined clays were chemically activated by the alkaline solutions of NaOH and Na2SiO3. The compressive strength was measured as a function of curing time at room temperature and 85°C. The results were compared with those of a pure kaolin sample. An amorphous aluminosilicate polymer was formed in all binders at both processing temperatures. The results show that, the mechanical properties depend on the type and amount of active aluminum silicates in the starting clay material, the impurities, and the processing temperature.

  16. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For

  17. Natural Radioactivity in Clay and Building Materials Used in Latvia

    Directory of Open Access Journals (Sweden)

    Riekstina D.

    2015-06-01

    Full Text Available This paper presents the results of natural radionuclide concentration and activity index study in materials used for construction in Latvia. Special attention is given to clay and clay ceramics. Concentrations of K-40 and Th- 232, U-238 radioactivity were determined using gamma-spectrometry method. In some building ware, maximal concentration of K-40 was 1440 Bq/kg, and of U-238 - 175 Bq/kg. In granite, the determined maximum concentration of Th-232 was 210 Bq/kg. It was found that radionuclide content in different period clay deposits can differ by more than two times, and up to five times in different clay ceramics. The results obtained are compared with analogous data from the other Baltic and North European countries.

  18. LABORATORY TESTING OF BENTONITE CLAYS FOR LANDFILL DESIGN AND CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Biljana Kovačević Zelić

    2007-12-01

    Full Text Available Top and bottom liners are one of the key construction elements in every landfill. They are usually made as compacted clay liners (CCLs composed of several layers of compacted clay with strictly defined properties or by the use of alternative materials such as: GCL – geosynthetic clay liner, BES – bentonite enhanced soils or bentonite/polymer mixtures. Following the state of the art experiences in the world, GCLs are used in Croatian landfills for several years, as well. Depending upon the location and the obeying function, GCLs have to fulfill certain conditions. A legislated compatibility criterion has to be proven by various laboratory tests. In the paper are presented the results of direct shear and chemical compatibility tests of GCLs as well as the results of permeability measurement of kaolin clay (the paper is published in Croatian .

  19. Stability of iron in clays under different leaching conditions

    Czech Academy of Sciences Publication Activity Database

    Doušová, B.; Fuitová, L.; Koloušek, D.; Lhotka, M.; Matys Grygar, Tomáš; Spurná, P.

    2014-01-01

    Roč. 62, 1-2 (2014), s. 145-152. ISSN 0009-8604 Institutional support: RVO:61388980 Keywords : Clays * Iron * Leaching Stability * Structure * Surface Properties Subject RIV: DD - Geochemistry Impact factor: 1.228, year: 2014

  20. Elastic deformation behaviour of Palaeogene clay from Fehmarn Belt area

    DEFF Research Database (Denmark)

    Awadalkarim, Ahmed; Foged, Niels Nielsen; Fabricius, Ida Lykke

    2014-01-01

    , bulk density, porosity, water content and saturation, elastic wave velocities, electrical resistivity and strain caused by mechanical loading. They were used together to interpret the geotechnical data. We aimed to see which physical property is a main controlling factor for the elasticity of the...... this study. Results of odometer tests done by Jessen et al. (2011) show that when Palaeogene clay is mounted in an odometer cell without access to water and loaded to its in-situ vertical effective stress and then saturated with its native salt water, the clay absorbs water and swells. This behaviour...... indicates that the Palaeogene clay in nature should expand at its mean effective in-situ stress. A study by Krogsbøll et al. (2012) provides some important clues about the deformation behaviour during unloading and swelling of the Palaeogene clay. In this study, we mainly focused on the elastic properties...

  1. Preparation of polystyrene–clay nanocomposite by solution intercalation technique

    Indian Academy of Sciences (India)

    P K Paul; S A Hussain; D Bhattacharjee; M Pal

    2013-06-01

    Polymer–clay nanocomposites of commercial polystyrene (PS) and clay laponite were prepared via solution intercalation technique. Laponite was modified suitably with the well known cationic surfactant cetyltrimethyl ammonium bromide by ion-exchange reaction to render laponite miscible with hydrophobic PS. X-ray diffraction analysis in combination with scanning electron microscopy gives an idea of structural and morphological information of PS–laponite nanocomposite for different varying organo-laponite contents. Intercalation of PS chain occurs into the interlayer spacings of laponite for low organo-laponite concentration in the PS–O-laponite mixture. However, aggregation and agglomeration occur at higher clay concentration. The molecular bond vibrational profile of laponite as well as PS–laponite nanocomposite have been explored by Fourier transform infrared spectroscopy. Thermogravimetric analysis along with differential scanning calorimetry results reveal the enhancement of both thermal stability and glass transition temperature of PS due to the incorporation of clay platelets.

  2. Weak Polyelectrolyte-Clay Assemblies: Physical Mechanisms of Biological Response

    Science.gov (United States)

    Sukhishvili, Svetlana; Pavlukhina, Svetlana; Zhuk, Iryna

    2014-03-01

    We report on a highly efficient, non-leachable antibacterial coating, consisting of an ultrathin nanocomposite hydrogel capable of hosting, protecting and delivering antibiofilm agents in response to bacterial infection. Constructed using layer-by-layer (LbL) deposition of clay nanoplatelets and a weak polyelectrolyte and loaded with an antimicrobial agent (AmA), the coatings was highly resistant to colonization by Staphylococcus aureus. The high antibiofilm activity of the coating results from a combination of highly localized, bacteria-triggered AmA release and hydrogel swelling, as well as retention of AmA by clay nanoplatelets. We discuss the dependence of rheological and swelling properties of weak polyelectrolyte-clay assemblies on film thickness, clay platelet orientation and environmental pH.

  3. Poly(vinylidene fluoride)/Clay Nanocomposites by Melt Compounding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The crystalline structures, morphologies, and mechanical properties of poly(vinylidene fluoride)/clay nanocomposites were studied using X-ray diffraction(XRD), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), polarized optical microscopy(POM), and tensile tests. The results of XRD and TEM show that organoclays are dispersed in the poly(vinylidene fluoride)(PVDF) matrix. A clay-induced crystal transformation from α-phase to β-phase of PVFD was confirmed by XRD and FTIR. Clay layers restricted the growth of spherulite. The tensile tests indicate that the tensile modulus and yield strength as well as the elongation at break decrease when clay is loaded.

  4. Studies on structural properties of clay magnesium ferrite nano composite

    Science.gov (United States)

    Kaur, Manpreet; Singh, Mandeep; Jeet, Kiran; Kaur, Rajdeep

    2015-08-01

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m2/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent.

  5. Studies on structural properties of clay magnesium ferrite nano composite

    International Nuclear Information System (INIS)

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m2/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent

  6. 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.

  7. International Association for the Study of Clays(AIPEA)

    Institute of Scientific and Technical Information of China (English)

    David L.Bish

    2007-01-01

    @@ During the 18th International Geological Congress in London in 1948, the clay scientists present met to discuss international cooperation and exchange of information within their common field of research.

  8. Clay mineralogy of weathering profiles from the Carolina Piedmont.

    Science.gov (United States)

    Loferski, P.J.

    1981-01-01

    Saprolite profiles (12) that formed over various crystalline rocks from the Charlotte 1o X 2o quadrangle showed overall similarity in their clay mineralogy to depths of 6 to 45 m indicating control by weathering processes rather than by rock type. Most saprolite contained 10-25% clay, and ranged 3 to 70%. Kaolinite and halloysite composed = or >75% of the clay fraction of most samples. The ratio kaolinite:halloysite ranged widely, from 95% kaolinite to 90% halloysite, independent of depth. Clay-size mica was present in all profiles, and ranged 5-75% over a sericite schist. Mixed-layer mica-smectite and mica-vermiculite were subordinate; discrete smectite and vermiculite were rare. The abundance of halloysite indicates a continuously humid environment since the time of profile formation, because of the rapidity with which halloysite dehydrates irreversibly. -R.S.M.

  9. PREPARATION AND CHARACTERIZATION OF POLYAMIDE 11/CLAY NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Min Yu; Qin Zhang; Qiang Fu

    2004-01-01

    Polyamide 11 (PA 11) is a widely used polyamide resin, but its application is limited since the impact properties,tensile strength, and thermal properties are not very satisfactory for industrial application. In order to improve the mechanical properties of PA 11, in this paper, the preparation of polyamide 11/clay nanocomposites (PACN) via in-situ intercalated polymerization was reported. SEM, TEM and XRD were employed to investigate the dispersion of clay sheet in the matrix.The results indicate that clay layers were homogeneously dispersed in PA11 matrix on a nano-scale, and an exfoliated and intercalated structure co-existed in the composites. The mechanical and thermal properties of the obtained nanocomposites were improved to certain extent by the addition of clay.

  10. Origin of Quaternary Red Clay of Southern Anhui Province

    Institute of Scientific and Technical Information of China (English)

    HUXUEFENG; YUANGUODONG; 等

    1998-01-01

    The particle-size distribution,heavy mineral constituents and rare earth elements(REE) characteristics of the Quaternary red clay of southern Anhui Province were studied to explore the origin of the clay.The results showed that the clay had some properties of areolian deposits,which could be compared with,those of the loess in North China ;and its chondrite-normalized curves of REE were similar to those of the Xiashu loess implying tha they shared the same orighin.It was concluded in combination with the results rported by other researchers that the Quaternary red clay of southern Anhui Province originated from aolian deposts, and this could reveal the cycles of warm and cold climates in the area during the Quaternary period.

  11. 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

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For

  12. Preliminary dating study of clay tablet from Neo-Babylonian period

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rodrigo P. da, E-mail: rodrigo.silva@unasp.edu.br [Centro Universitario Adventista de Sao Paulo (UNASP), Sao Paulo, SP (Brazil); Tudela, Diego R.G.; Hazenfratz, Roberto; Munita, Casimiro S., E-mail: camunita@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Tatumi, Sonia H.; Yee, Marcio; Mittani, Juan C. R., E-mail: sonia.tatumi@gmail.com [Universidade Federal de Sao Paulo (UNIFESP), Santos, SP (Brazil)

    2013-07-01

    This work focuses on the archaeometric study of three clay tablet fragments named BAB{sub 1}, BAB{sub 2} and BAB{sub 3}. One of them, BAB{sub 1}, probably was manufactured in the Middle East during the Neo-Babylonian period, and contains inscriptions in cuneiform characters. The other two samples BAB{sub 2} and BAB{sub 3} also contain cuneiform characters, but in incomplete sentences. Typological studies in agreement with historical records suggest that the artifacts were manufactured in the 6{sup th} century B.C. during the dynasty of Nebuchadnezzar, Great King of Babylon. The age was determined by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The annual dose rate for both TL and OSL dating was calculated with uranium, thorium and potassium concentrations determined by instrumental neutron activation analysis (INAA). Additional studies were performed using electron paramagnetic resonance (EPR) to determine the firing temperature, in order to verify if different firing temperatures were associated to different ages. Finally, X-ray diffraction analysis (XRD) was applied to the fragments to verify potential mineralogical differences, indicating different technological choices in the ceramic manufacture (like the choice of clay pastes and firing temperature). (author)

  13. Environmental Radioactivity Comparison Study for the Glaze-Clay Surface of Ceramic Tiles by Tracks Technique

    International Nuclear Information System (INIS)

    Tracks Density, radon concentration, radon exhalation rates and radium concentration were measured from ceramic tiles for both of glaze and clay by using the track technique, containing CR-39, to estimate the radiation exposure in the vicinity of ceramic tile. For ceramic tiles of wall, the average of tracks density, the radon concentration, radon exhalation rates and radium concentration were found in the range 230-356 tracks.cm-2, 389-600 Bq.m-3, 21-31 mBq.m-2.h-1, 16-25 Bq.kg-1, respectively. While for ceramic tiles of floor, the average of tracks density, the radon concentration, radon exhalation rates and radium concentration were found in the range 274-509 tracks.cm-2, 463-860 Bq.m-3, 25-46 mBq.m-2.h-1, 19-46 Bq.kg-1, respectively. The average level of radon concentrations caused by these ceramic tiles for Egyptian companies covering both of wall, floor, glaze and clay giving an annual exposure dose 22±2 mSv.y-1 which is higher than internationally recommended range

  14. Preliminary dating study of clay tablet from Neo-Babylonian period

    International Nuclear Information System (INIS)

    This work focuses on the archaeometric study of three clay tablet fragments named BAB1, BAB2 and BAB3. One of them, BAB1, probably was manufactured in the Middle East during the Neo-Babylonian period, and contains inscriptions in cuneiform characters. The other two samples BAB2 and BAB3 also contain cuneiform characters, but in incomplete sentences. Typological studies in agreement with historical records suggest that the artifacts were manufactured in the 6th century B.C. during the dynasty of Nebuchadnezzar, Great King of Babylon. The age was determined by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The annual dose rate for both TL and OSL dating was calculated with uranium, thorium and potassium concentrations determined by instrumental neutron activation analysis (INAA). Additional studies were performed using electron paramagnetic resonance (EPR) to determine the firing temperature, in order to verify if different firing temperatures were associated to different ages. Finally, X-ray diffraction analysis (XRD) was applied to the fragments to verify potential mineralogical differences, indicating different technological choices in the ceramic manufacture (like the choice of clay pastes and firing temperature). (author)

  15. Lead removal from aqueous solutions by a Tunisian smectitic clay

    Energy Technology Data Exchange (ETDEWEB)

    Chaari, Islem [Laboratoire de Georessources CERTE BP 95, 2050 Hamam-Lif (Tunisia)], E-mail: chaariislem@yahoo.fr; Fakhfakh, Emna; Chakroun, Salima [Laboratoire de Georessources CERTE BP 95, 2050 Hamam-Lif (Tunisia); Bouzid, Jalel; Boujelben, Nesrine [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia); Feki, Mongi [Unite de chimie industrielle I, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia); Rocha, Fernando [MIA, Universite d' Aveiro, Campus de Santiago, 3810 Aveiro (Portugal)], E-mail: frocha@geo.ua.pt; Jamoussi, Fakher [Laboratoire de Georessources CERTE BP 95, 2050 Hamam-Lif (Tunisia)

    2008-08-15

    The adsorption of Pb{sup 2+} ions onto Tunisian smectite-rich clay in aqueous solution was studied in a batch system. Four samples of clay (AYD, AYDh, AYDs, AYDc) were used. The raw AYD clay was sampled in the Coniacian-Early Campanian of Jebel Aidoudi in El Hamma area (South of Tunisia). AYDh and AYDs corresponds to AYD activated by 2.5 mol/l hydrochloric acid and 2.5 mol/l sulphuric acid, respectively. AYDc corresponds to AYD calcined at different temperatures (100, 200, 300, 400, 500 and 600 deg. C). The raw AYD clay was characterized by X-ray diffraction, chemical analysis, infrared spectroscopy and coupled DTA-TGA. Specific surface area of all the clay samples was determined from nitrogen adsorption isotherms. Preliminary adsorption tests showed that sulphuric acid and hydrochloric acid activation of raw AYD clay enhanced its adsorption capacity for Pb{sup 2+} ions. However, the uptake of Pb{sup 2+} by AYDs was very high compared to that by AYDh. This fact was attributed to the greater solubility of clay minerals in sulphuric acid compared to hydrochloric acid. Thermic activation of AYD clay reduced the Pb{sup 2+} uptake as soon as calcination temperature reaches 200 deg. C. All these preliminary results were well correlated to the variation of the specific surface area of the clay samples. The ability of AYDs sample to remove Pb{sup 2+} from aqueous solutions has been studied at different operating conditions: contact time, adsorbent amount, metal ion concentration and pH. Kinetic experiments showed that the sorption of lead ions on AYDs was very fast and the equilibrium was practically reached after only 20 min. The results revealed also that the adsorption of lead increases with an increase in the solution pH from 1 to 4.5 and then decreases, slightly between pH 4.5 and 6, and rapidly at pH 6.5 due to the precipitation of some Pb{sup 2+} ions. The equilibrium data were analysed using Langmuir isotherm model. The maximum adsorption capacity (Q{sub 0

  16. Clay content of argillites: Influence on cement based mortars

    OpenAIRE

    Habert, Guillaume; CHOUPAY, Nathalie; Escadeillas, Gilles; MONTEL, Jean Marc; Guillaume, D

    2009-01-01

    The pozzolanic activity of four heated powders containing different clays has been tested. Mineral transformations during calcination from 20 to 900 °C have been followed by X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC). Compressive strength tests were performed at 1, 7 and 28 days on cement-clay mortars using 30% of pozzolanic material as a replacement by mass for cement. Calcination temperatures corresponded to the stages of potentially high reactivity identified by XR...

  17. 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...

  18. Clay Mineralogy of Various Marginal Soils in Vietnam

    OpenAIRE

    Nguyen, Quang Hai; Egashira, Kazuhiko

    2008-01-01

    Various marginal soils derived from different parent materials were collected from different landforms and agro-ecological regions in Vietnam and were subjected to clay mineral analysis in addition to particle-size analysis. The result showed that the particle-size distribution of the soils had a close relationship with the landform. The clay content was highest for the soils from the meander floodplain and inland valley, followed by the soil from the hill and lowest for the soils from the ...

  19. 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...

  20. Neogene and Quaternary clay minerals in the southern North Sea

    OpenAIRE

    Adriaens, Rieko

    2015-01-01

    In this work it was demonstrated how the systematic quantitative analysis of clay minerals yields a better understanding of specific geologicaland stratigraphical issues. In the first part, a reliable and accurate method for the X-ray diffraction analysis of clay minerals, and glauconite minerals in particular, was established. Especially the decomposition and separate quantification of the 060-region in random oriented powder diffraction patterns was found a powerful tool for the characte...

  1. Modification of bentonite clay and application on polypropylene nano composites

    International Nuclear Information System (INIS)

    This work consisted on the modification of Brasgel PA clay with ionic surfactant Praepagen WB and its incorporation into polypropylene. The results of infrared and DR-X was showed that the intercalation of surfactant in the clay and the incorporation of organoclay in PP matrix resulted in the formation of an intercalated structure. The impact strength of PP increased with the incorporation of organoclay. (author)

  2. A Wii-related clay-shoveler's fracture.

    Science.gov (United States)

    Brown, Christopher N; McKenna, Patrick

    2009-01-01

    A 38-year-old man presented to the accident and emergency department complaining of severe neck pain. This had started immediately after swinging his Wii game console control during a rather vigorous game. An X-ray demonstrated a clay-shoveler's fracture of C7. This had radiological features to suggest an acute injury. This is the first report of a clay-shoveler's fracture strongly suggestive of being related to the use of a Wii console. PMID:19882086

  3. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    OpenAIRE

    Marc in het Panhuis; Holly Warren; Higgins, Thomas M.

    2011-01-01

    The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs) and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that ...

  4. Quantification of clay minerals by combined EWA/XRD method

    Institute of Scientific and Technical Information of China (English)

    XU; Jianhong; (徐建红); XU; Jianhong; (徐建红); T.; R.; Astin; PAN; Mao; (潘懋)

    2001-01-01

    Illite has been considered the main constraint on permeability in the Morecambe Gas Field, East Irish Sea, UK. Previous research has emphasized the morphology rather than the amount of clay minerals. By applying a new method of clay mineral quantification, EWA/XRD, and applying statistical analysis methods, we are able to establish a quantitative model of illite distribution in the field. The result also leads to a better understanding of permeability distribution in reservoir sandstones.

  5. Heating pulse tests under constant volume on natural Boom clay

    OpenAIRE

    Lima, Analice; Romero Morales, Enrique Edgar; Gens Solé, Antonio; Muñoz, Juan Jorge; Li, X. L.

    2009-01-01

    Boom clay formation is a potential natural host rock for geological disposal of High Level Nuclear Waste in Belgium. Heating pulse tests with controlled power supply (maximum temperature was limited to 85ºC) and controlled hydraulic boundary conditions were performed under nearly constant volume conditions to study the impact of thermal loads on this clay formation. Selected test results on impact borehole samples retrieved in horizontal direction are presented and discussed. Attention is foc...

  6. Heating pulse tests under constant volumen on natural Boom clay.

    OpenAIRE

    Lima, Analice; Romero Morales, Enrique Edgar; Gens Solé, Antonio; Muñoz, Juan Jorge; Li, Xiangling

    2010-01-01

    Boom clay formation is a potential natural host rock for geological disposal of high-level nuclear waste in Belgium. Heating pulse tests with controlled power supply (maximum temperature was limited to 85°C) and controlled hydraulic boundary conditions were performed under nearly constant volume conditions to study the impact of thermal loading on the clay formation. Selected test results of intact borehole samples retrieved in horizontal direction are presented and discussed. The study...

  7. 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

  8. Clay pigments as indicators of paint authenticity and material provenance

    Czech Academy of Sciences Publication Activity Database

    Bezdička, Petr; Grygar, Tomáš; Hradil, David; Hradilová, J.

    2004-01-01

    Roč. 4, S (2004), s. 13. ISSN 0365-8066. [Mid-European Clay Conference /2./. Miskolc, 20.09.2004-24.09.2004] R&D Projects: GA MŠk LN00A028; GA ČR GA203/04/2091 Institutional research plan: CEZ:AV0Z4032918 Keywords : earthy pigments * clay minerals * microanalysis Subject RIV: CA - Inorganic Chemistry

  9. Irradiation effects in clays. Environmental and geological applications.

    OpenAIRE

    Fourdrin, Chloé

    2009-01-01

    Irradiation defects in minerals present at the earth surface gave rise to an important number of studies. Among these minerals, clays possessed properties (cationic exchange capacity, swelling properties) which make them suitable candidate for the retention of actinides in the context of high level radioactive waste storage. In order to insure the stability of the clay located around the waste, it is necessary to study their physico-chemical properties after irradiation. This thesis is divide...

  10. Evaluation of peanut hulls as an alternative to bleaching clays

    OpenAIRE

    Hassanein, M. M.M.; El- Shami, S. M.; Taha, F. S.

    2011-01-01

    Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller’s e...

  11. Small anthropomorphic figurines in clay at Gipka Neolithic settlements

    OpenAIRE

    Loze, Ilze

    2015-01-01

    Miniature Neolithic figurines in clay are a special topic of research. This especially concerns areas where their representation has so far been poor. While carrying out archaeological excavations in Northern Kurzeme, the north west coastal dune yone of Riga Bay, a ritual-like complex was recovered at Gipka A site belonging to the local Culture of Pit Ceramics. It consists of several large and smaller fireplaces and pits, with the finds of fragmentary clay figurines recovered under the palisa...

  12. Thermo-mechanical behaviour of a compacted swelling clay

    OpenAIRE

    TANG, Anh Minh; Cui, Yu-Jun; Barnel, Nathalie

    2008-01-01

    International audience Compacted unsaturated swelling clay is often considered as a possible buffer material for deep nuclear waste disposal. An isotropic cell permitting simultaneous control of suction, temperature and pressure was used to study the thermo-mechanical behaviour of this clay. Tests were performed at total suctions ranging from 9 to 110 MPa, temperature from 25 to 80 °C, isotropic pressure from 0.1 to 60 MPa. It was observed that heating at constant suction and pressure indu...

  13. Reconsolidation of Clay Pre-strained in Shear Mode

    OpenAIRE

    Borchtchev, Alexei S

    2015-01-01

    Through the past years unexpectedly large settlements of the existing structures have been registered as a result of geotechnical site works, and especially, due to the boring and installation of steel core piles. One of the recognized effects related to the bored piles which may lead to the settlements, is remoulding and reconsolidation of soft clay in a limited zone around the pile shaft during installation phase. The radial extent of the remoulded clay around the bored shaft remains unk...

  14. 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)

  15. Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites

    OpenAIRE

    Jiang-Jen Lin; Ying-Nan Chan; Yi-Fen Lan

    2010-01-01

    Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene)-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH) with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 Å (X-ray diffraction) as well as hydrophobic pr...

  16. 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

  17. Mechanisms of erosion in miocene clays from the Tudela formation (Bardenas Reales, Navarra, Spain)

    International Nuclear Information System (INIS)

    In Bardenas Reales area (located in the central-western part of the Ebro Depression) several erosion rates have been measured along the last years. The mean annual erosion rates are of 32 Tm/Ha/yr. Due to semiarid conditions, precipitation is irregularly distributed along the year with maximums on spring and autumn when the great erosion is produced. There are intensity and quality thresholds below which erosion does not take place. In Bardenas Reales some erosion processes act (mud slides and armoured mud balls among others). Mud slides are mobilised on spring when the sediment have reached its plastic limit and could slide due to heavy rains. Armored mud balls are produced by the enhancement of popcorn cracks that individualize clays cores which are rounded by water. The same kind of strong precipitation that mobilised mud slides is the responsible of armoured mud balls destruction because the conditions to its maintenance are very limited. (Author) 9 refs.

  18. 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.

  19. 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.

  20. 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)

  1. Characterization of some clay deposits in South West Nigeria

    Directory of Open Access Journals (Sweden)

    Fatai Olufemi ARAMIDE

    2014-11-01

    Full Text Available Clay minerals are the most important industrial minerals whose application is dependent on its structure and chemical composition. Mineralogical, chemical compositions, phase constitutions, and microstructural morphology of certain clay minerals from three different deposits in south western Nigeria were investigated using state-of-the-art equipment. These were done with the intention of determining the appropriate application for the clay minerals. It was observed that the major phases in the clay samples from the three different deposits are kaolinite, microcline, muscovite/illite, plagioclase/albite and quartz. These phases were observed in varied percentages. It was concluded that sample A (Ifon clay which contains very low kaolinite (5.63%; could not use for making high temperature caliber refractories. But due to its high content of feldspar, it could be processed for the production of feldspar for glass and iron making industries. Sample B is considered to be appropriate for the production the refractory composite due to its most appropriate content of both kaolinite (23.74% kaolinite and feldspars (26.12% microcline and 11.28% plagioclase/albite which is necessary for producing mullite fibers in ceramic matrix at a temperature of around 1400oC. Sample C (Iseyin clay, which contains very low feldspars (3.00% microcline and 3.08% plagioclase/albite and high content of kaolinite was considered suitable for further processing for making high temperature caliber refractories.

  2. Laboratory evaluation of cement treated aggregate containing crushed clay brick

    Directory of Open Access Journals (Sweden)

    Liqun Hu

    2014-10-01

    Full Text Available The waste clay bricks from debris of buildings were evaluated through lab tests as environmental friendly materials for pavement sub-base in the research. Five sets of coarse aggregates which contained 0, 25%, 50%, 75% and 100% crushed bricks, respectively, were blended with sand and treated by 5% cement. The test results indicated that cement treated aggregate which contains crushed clay brick aggregate had a lower maximum dry density (MDD and a higher optimum moisture content (OMC. Moreover, the unconfined compressive strength (UCS, resilience modulus, splitting strength, and frost resistance performance of the specimens decreased with increase of the amount of crushed clay brick aggregate. On the other hand, it can be observed that the use of crushed clay brick in the mixture decreased the dry shrinkage strain of the specimens. Compared with the asphalt pavement design specifications of China, the results imply that the substitution rate of natural aggregate with crushed clay brick aggregate in the cement treated aggregate sub-base material should be less than 50% (5% cement content in the mixture. Furthermore, it needs to be noted that the cement treated aggregate which contains crushed clay bricks should be cautiously used in the cold region due to its insufficient frost resistance performance.

  3. 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

  4. 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.)

  5. Clay-based grout injection in crystalline rock

    International Nuclear Information System (INIS)

    In the sealing of an underground disposal facilities for the high-level radioactive waste, a concept of the clay grouting in the sealing of the underground facilities applied to the hard rock is summarized, based on the results of clay grouting experiments Japan Nuclear Cycle Development Institute (JNC) has performed. JNC performed the clay grouting experiments in-situ of the hard rock. In the experiments, clay grout slurry was injected to the fractures on the floor of the test tunnel and to the excavated damage zone around the key cut off the excavated damage zone along the tunnel. Through the results of these experiments, the injected grout slurry to the target excavated damage zone area improved the hydraulic conductivity of the target area using the injection boreholes opened from the wall of the tunnel. Regarding the adequate design of the clay grouting in the hard rock, information of the fracture characterization (scale and distribution), distribution of the excavated damage zone (hydraulic characteristics), selection of the clay material, injection technique, target area of the injection of the grout (position and region) and so on is required. (author)

  6. 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.

  7. Synthesis and characterization of silica nanoparticles from clay

    Directory of Open Access Journals (Sweden)

    Usama Zulfiqar

    2016-03-01

    Full Text Available We report a method to synthesize silica nanoparticles from bentonite clay. A series of thermal and acid treatment processes was performed on bentonite clay to lower the alumina and increase the silica content. The obtained silica rich clay was treated in two different concentrations (10 wt% and 40 wt% with sodium hydroxide solution to form sodium silicate solutions (SSS. One type of SSS was hydrolyzed with three different concentrations (5 M, 10 M and 15 M of nitric acid in the presence of ethanol as cosolvent while the other SSS was hydrolyzed with nitric acid in the presence of three different quantities (10 ml, 20 ml and 30 ml of ethanol as cosolvent. A range of silica particle sizes from nanometer to micrometer was obtained by varying the contents of silica rich clay, HNO3, and ethanol. It was observed that the concentration of silica rich clay and HNO3 had a direct effect on the particle size. The increase in the quantity of ethanol from 10 ml to 20 ml produced bimodal particles of nanometer and micrometer size, which maintained at 30 ml. Inductively coupled plasma optical emission spectroscopy, atomic absorption spectroscopy, X-ray fluorescence, scanning electron microscopy and X-ray diffraction were utilized to characterize the clay, SSS and nanoparticles.

  8. Prevention of Seepage of Unsaturated Clay by Chemical Treatment

    Institute of Scientific and Technical Information of China (English)

    徐则民; 杨立中; 刘丹

    2003-01-01

    The aim of the study is to seek a simple and inexpensive method to prevent the permeability rise of unsaturated clay caused by evaporation process and to raise its imperviousness. Taking Chengdu clay as an example, four treatment schemes were tried. Na2CO3 could reduce conspicuously the permeability of the saturated clay, but could not limit the permeability rise in the alternate wetting and drying process. NaOH had a similar effect to Na2CO3. NaCl could not only decrease the saturated hydraulic conductivity, but could also effectively contain the permeability rise caused by evaporation. CH3COONa had a similar effect to NaCl. The mechanism of Na2CO3, NaOH, NaCl and CH3COONa decreasing the saturated hydraulic conductivity of the clay is that Na+ transformed Ca-montmorillonites in the original clay into Na-montmorillonites and the transformation reduces the sizes of effective pores and the effective porosity of the clay.

  9. Porous networks derived from synthetic polymer-clay complexes

    International Nuclear Information System (INIS)

    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 N2 BET surface area of 200 M2/gm, even after calcination. This increases by 20--50% for the synthetic polymer-hectorites after the polymer is removed by calcination

  10. Transport of dodecane in sand and clay columns

    International Nuclear Information System (INIS)

    Contamination of soil by petroleum hydrocarbons is a significant problem in the United States. Release of nonaqueous phase liquids (NAPLs) petroleum contaminants at or near the ground surface can migrate through the vadose zone to the groundwater. In contaminated coarse-textured soils containing abrupt interfaces with clay layers, petroleum hydrocarbons can accumulate at the clay interface due to restricted water flow through the clay layer. In addition, the soil matrix can act as a sink to which the petroleum contaminant becomes adsorbed, resulting in a difficult remediation scenario. Soil columns were erected using six inch PVC pipe. Three types of columns were constructed: one comprised only of sand, one of only clay, and one with both clay and sand layers. Each column was 24 inches long and duplicate columns were prepared, as well. Dodecane was introduced into the columns at a single mid-point at the top of each column as a one-time event. Four sets of each type of column were constructed to permit sampling of the column soil at four subsequent time intervals. Each column was disassembled at specified times and the contaminant concentration levels were quantified as a function of distance into the column. Results of this study contribute to a more comprehensive understanding of the behavior of NAPLs in contaminated heterogeneous soils with high clay content

  11. 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...

  12. New polyelectrolyte complex from pectin/chitosan and montmorillonite clay.

    Science.gov (United States)

    da Costa, Marcia Parente Melo; de Mello Ferreira, Ivana Lourenço; de Macedo Cruz, Mauricio Tavares

    2016-08-01

    A new nanocomposite hydrogel was prepared by forming a crosslinked hybrid polymer network based on chitosan and pectin in the presence of montmorillonite clay. The influence of clay concentration (0.5 and 2% wt) as well as polymer ratios (1:1, 1:2 and 2:1) was investigated carefully. The samples were characterized by different techniques: transmission and scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, swelling degree and compression test. Most samples presented swelling degree above 1000%, which permits characterizing them as superabsorbent material. Images obtained by transmission electron microscopy showed the presence of clay nanoparticles into hydrogel. The hydrogels' morphological properties were evaluated by scanning electron microscope in high and low-vacuum. The micrographs showed that the samples presented porous. The incorporation of clay produced hydrogels with differentiated morphology. Thermogravimetric analysis results revealed that the incorporation of clay in the samples provided greater thermal stability to the hydrogels. The compression resistance also increased with addition of clay. PMID:27112858

  13. Fixing of heavy metals by some inflated Tunisian clays

    International Nuclear Information System (INIS)

    At the time of discharge of the water polluted in a natural environment and thanks to the properties of retention, adsorption and exchange of ions, clays constitute a natural barrier which will be able to limit the toxicity and the propagation of the pollutants. To contribute to the development of clays layers of Tunisia in the field of water treatments, we undertook with a mineralogical and physicochemical characterization of some inflating clays. The characteristics of these clays will be exploited for the study of the retention by adsorption of some heavy metals. The isotherms of adsorption, of heavy metals in aqueous solution by these natural clays before and after acid activation, are studied. The influence of several parameters on the fixing of heavy metals on clay such as the factors relating to the medium of adsorption (agitation, pH, time of contact, temperature. etc) and those relating to the adsorbent (mass, granulometry, impurities. etc) was studied in order to optimize the operating conditions of adsorptions.

  14. SBR Brazilian organophilic/clay nanocomposites;Nanocompositos SBR/argila organofilica brasileira

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Thiago R.; Valenzuela-Diaz, Francisco R., E-mail: frrvdiaz@usp.b [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. Eng. Metalurgica e de Materiais; Morales, Ana Rita; Paiva, Lucilene B. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Quimica

    2009-07-01

    The aim of this work is the obtaining of SBR composites using a Brazilian raw bentonite and the same bentonite treated with an organic salt. The clays were characterized by XRD. The clay addition in the composites was 10 pcr. The composites were characterized by XRD and had measured theirs tension strength (TS). The composite with Brazilian treated clay showed TS 233% higher than a composite with no clay, 133% higher than a composite with Cloisite 30B organophilic clay and 17% lower than a composite with Cloisite 20 A organophilic clay. XRD and TS data evidence that the composite with Brazilian treated clay is an intercalated nanocomposite. (author)

  15. Using of clay-salt slimes of 'Belaruskali' factory as a sorbents of radionuclide

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The effective sorbents for decrease of radionuclide migration in soil and prevention of pollution risk of soil and underground water by radionuclide, according to available practical experience on minimization of consequences of the Chernobyl NPP accident, are: clay minerals of layered structure of type 2:1, potash fertilizers for 137Cs and potassium rocks for 90Sr. The analysis of literary data shows, those there two base kinds of industrial waste are formed at sylvinite ore processing almost at all potassium plants of the world: - Solid halite rejects material - Liquid waste in the form of clay-salt slimes. There is about 9 % of halite waste from annual formation using in Belarus, clay-salt slimes (CSS) are not used in general and all the volume goes to slime storage. Clay-salt slimes are the waste products of potassium production being formed in the course of sylvinite ore conversion at processing plants of the Industrial centre 'Belaruskali'. Up to the present moment about 80 millions of tones of clay-salt slimes have been accumulated in Soligorsk industrial zone, and their annual formation makes up about 2.0-2.5 millions of tones. The volume of industrial waste collected in Republic of Belarus allows considering CSS as a possible source of low-cost raw material for reception of products with different functions. On the other hand by estimation of national and international experts such quantity of industrial waste, especially liquid, represents ecological danger. Taking into account this circumstance the situation with industrial waste disposal in Soligorsk industrial area of Belarus which was estimated by international experts as critical one and it needs the cardinal measures for further environment pollution prevention. There is considerable volume of liquid radioactive waste is formed at the Nuclear Power Plant operation. Modern tendencies of radioactive waste disposal are directed on

  16. Hollow clay tile wall program summary report

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, R.C.; Jones, W.D. [Gilbert/Commonwealth, Inc., Oak Ridge, TN (United States); Beavers, J.E. [MS Technology, Inc. (United States)

    1995-07-30

    Many of the Y-12 Plant buildings, constructed during the 1940s and 1950s, consist of steel ed concrete framing infilled with hollow clay tile (HCT). The infill was intended to provide for building enclosure and was not designed to have vertical or lateral load-carrying capacity. During the late 1970s and early 1980s, seismic and wind evaluations were performed on many of these buildings in conjunction with the preparation of a site-wide safety analysis report. This analytical work, based on the best available methodology, considered lateral load-carrying capacity of the HCT infill on the basis of building code allowable shear values. In parallel with the analysis effort, DOE initiated a program to develop natural phenomena capacity and performance criteria for existing buildings, but these criteria did not specify guidelines for determining the lateral force capacity of frames infilled with HCT. The evaluation of infills was, therefore, based on the provisions for the design of unreinforced masonry as outlined in standard masonry codes. When the results of the seismic and wind evaluations were compared with the new criteria, the projected building capacities fell short of the requirements. Apparently, if the buildings were to meet the new criteria, many millions of dollars would be required for building upgrades. Because the upgrade costs were significant, the assumptions and approaches used in the analyses were reevaluated. Four issues were identified: (1) Once the infilled walls cracked, what capacity (nonlinear response), if any, would the walls have to resist earthquake or wind loads applied in the plane of the infill (in-plane)? (2) Would the infilled walls remain within the steel or reinforced concrete framing when subjected to earthquake or high wind loads applied perpendicular to the infill (out-of-plane)? (3) What was the actual shear capacity of the HCT infill? (4) Was modeling the HCT infill as a shear wall the best approach?

  17. Investigation of microbial nitrate reduction processes in Boom Clay slurries

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. At the moment, many countries are considering geological disposal of nuclear waste in a clay formation. In Belgium, the Boom Clay is currently studied as a potential host formation, due to its interesting physicochemical properties, which cause a delay and spread in time of the migration of leached radionuclides. However, waste disposal will have a certain impact on the barrier function of the clay. Emplacement of the Belgian bituminized waste, Eurobitum, which contains 20 to 30 weight% NaNO3, is expected to result in certain perturbations of the clay barrier. Both a mechanical disturbance due to an osmotically induced pressure increase and a physico-chemical disturbance caused by the leaching of NaNO3 from the Eurobitum into the clay can be expected. One of these chemical perturbations is the microbial reduction (assimilatory and/or dissimilatory) of nitrate and nitrite in Boom Clay. Assimilation of nitrate or nitrite leads to the formation of R-NH2, while denitrification (dissimilatory pathway) results in gas production (NO, N2O and N2). In some bacterial species, a dissimilative reduction of nitrite into ammonia can also occur, followed by the excretion of NH3 into the medium. A high gas pressure could result in a gas-driven transport of pore water (i.e. two-phase transport), and hence of radionuclides, and possibly in a fracturing of the clay (i.e. gas breakthrough). Besides these microbial reduction processes, abiotic reduction of nitrate and nitrite by Boom Clay components cannot be excluded. The oxidation of Boom Clay components would result in a less reducing capacity towards redox-sensitive radionuclides, and thus could increase their migration rate in the oxidized Boom Clay. To study the microbial reduction processes of nitrate and nitrite in Boom Clay, batch reactor tests were performed. In a first series of tests, Boom Clay slurries (solid/liquid weight ratio 2/3 g/ml) were mixed in two reactors to

  18. Study of Clay Materials as Host Rock for Candidate of Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    Generally some rock types such as crystalline, volcanic and clay materials have been using as host rock for radwaste disposal site. Objective of the paper is to completing the clays study for radwaste disposal through literature study which has related to information of clay. The characteristic of clay rocks, both physically and chemically has good potential for radwaste disposal site, due to this reason the clay rocks has been used for radwaste disposal in another countries. (author)

  19. Mapping of quick clay using geoelectrical imaging and CPTU-resistivity

    OpenAIRE

    Dahlin, Torleif; Löfroth, Hjördis; Schälin, David; Suer, Pascal

    2013-01-01

    Quick clay has a major impact on landslide risk and it is therefore of considerable interest to map its presence and extent. In Sweden, quick clay has been involved in most landslides in soft clay with serious consequences. The predominant method for detection of quick clay in Sweden has been to take undisturbed samples and to perform fall-cone tests on the clay in its undisturbed and remoulded state. Originally deposited in saltwater in a marine environment, the salt maintains the stability ...

  20. Geological characteristics of the Gorna Brca clay deposit, Veles (Republic of Macedonia)

    OpenAIRE

    Spasovski, Orce; Mircovski, Vojo; Bojadjiev, Petre

    2005-01-01

    Detailed geological investigations showed that the Dolna Brca clay deposit and the vicinity are composed of Triassic and Quaternary sediments and Plocene layers. Clay ore bodies occur in the Plocene sediments in various thickness and irregular shape. According to their chemical composition it is believed that the clays from the deposit are good for the production of rough ceramics. In terms of their mineralogy the clays are affiliated to illite clays. They are composed of illite, quartz and o...

  1. 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

  2. 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)

  3. 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...

  4. 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...

  5. 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

  6. 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

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

    International Nuclear Information System (INIS)

    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 10-3 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

  8. Clay Veins and Clay Minerals in the Granitic Rocks in Hiroshima and Shimane Prefectures, Southwest Japan : Effect of the hydrothermal activities on the decomposition of the granitic rocks

    OpenAIRE

    Kitagawa, Ryuji

    1986-01-01

    This paper deals with the clay minerals found in the granitic rocks distributed in Hiroshima and Shimane Prefectures with special reference to the effects of hydrothermal activities on the decomposition process of the granitic rocks. Many clay veins and hydrothermal clay deposits are commonly developed in the granitic rocks and their mode of occurrences were investigated in detail. the preferred orientations of the clay veins and microcracks found in the constituent minerals of granitic rocks...

  9. Radiological impacts of the usability of clay and kaolin as raw material in manufacturing of structural building materials in Turkey

    International Nuclear Information System (INIS)

    The aim of the present study is to measure the natural radioactivity due to the presence of radionuclides in clay and kaolin, used widely as raw materials in ceramics, bricks and cement industries, and to assess the possible radiological hazards associated with these raw materials. The activity concentrations of natural radionuclides 226Ra, 232Th and 40K in 50 samples collected from different quarries were measured by means of gamma-ray spectrometry with an HPGe detector. The mean values of the measured activity concentrations of 226Ra, 232Th and 40K for clay samples were found to be 39.3 ± 22.7 Bq kg-1, 49.6 ± 27.9 Bq kg-1 and 569.5 ± 181.0 Bq kg-1, and for kaolin samples 82.0 ± 37.3 Bq kg-1, 94.8 ± 49.2 Bq kg-1 and 463.6 ± 544.9 Bq kg-1, respectively. These levels are comparable to those appearing in clays of European countries. The radium equivalent activity and the external (gamma) and internal (alpha) hazard indices were calculated to assess the potential radiological hazard. The calculated gamma and alpha indices varied from 0.19 to 1.17 and from 0.04 to 0.47 for clay samples and from 0.36 to 1.75 and from 0.08 to 0.63, respectively. The mean value of the gamma index for the clay samples (0.57 ± 0.24) is slightly above the criterion of 0.5 corresponding to an annual effective dose of 0.3 mSv, while the mean value of the gamma index for the kaolin samples (0.90 ± 0.49) is below the criterion of unity corresponding to an annual effective dose of 1 mSv. The calculated alpha index values for all samples are below the recommended upper level.

  10. 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.

  11. Clay iron interactions under high ph conditions: an experimental approach

    International Nuclear Information System (INIS)

    Many designs for geological disposal facilities for radioactive and toxic wastes envisage the use of clay-rich rock as engineering barriers. It is thus necessary to evaluate changes that can affect the long-term behaviour of the clay. In some instances, clay may be in contact with cement and/or a metallic iron canister. The saturation of cements with groundwater produces an alkaline pore fluid with a pH in the range 10-13,5. This fluid may enter the clay barrier and significantly modifies the pH of the interstitial waters, and subsequently alters, the clay and its physical and chemical properties. Studies have already observed various modifications of the clay mineralogy in alkaline conditions: dissolution of smectite, formation of illite, of calcium silicate hydrates, of zeolites and of lizardite. But the presence of an iron canister might induce other mechanisms and transformations. Clay-iron interactions under alkaline conditions have been studied experimentally using a bentonite (MX-80) as starting product. The presence of an iron canister has been simulated by introducing iron oxide powder (magnetite), metallic iron powder and metallic iron plate. The presence of a cement pore fluid has been simulated by an alkaline and Ca, Na-rich fluid prepared from analytical grade chemicals. The fluid pH was 12,3. Solid/solution systems were prepared under argon atmosphere in a glove box to obtain oxygen-free systems and put in autoclaves at 80 C, 150 C and 300 C. The durations of the experiments were 3,6 and 9 months, the vessels being completely static during experiments with the iron plate at the bottom to obtain information on the spatial changes as a function to the distance to the metallic iron plate. For each vessel, the sample was parted under argon atmosphere: one part collected close to the iron plate and the other part far from the iron plate; the iron plate itself was collected separately. (authors)

  12. Study of different disposal concepts in clay formations

    International Nuclear Information System (INIS)

    Within the scope of an R and D project which deals with the comparison of concepts in salt and clay formations the main work was to work out the major features of a final repository concept in clay for spent fuel and vitrified waste. The work focused on the topics safety, conceptual design, and economical aspects. The planning was carried out taking into account results of previous R+D projects and international experiences with repositories in clay (namely in France, Spain, Belgium and Switzerland). Open questions were to be identified for further research and development. The work was restricted to the final repository itself. Nevertheless, aspects of the siting procedure, of the final disposal casks, conditioning, long-term safety, and geochemical processes were also considered. The German Ministry of Economics and Labour represented by PtWT+E has funded the project. The project consisted of the following five work packages. Compilation of fundamentals and boundary conditions for the comparison: This included a compilation of the state of the art of national and international waste management concepts in clay. Furthermore, the amount of waste to be dealt with, cask materials, requirements for filling and closure material, and siting aspects were described. Disposal cask concepts: compilation of available information about waste conditioning processes and cask concepts including cost estimates.Conceptual design of a repository and repository techniques: the conceptual design of a repository in the host rock clay was performed considering the surface and subsurface installations and the required equipment including cost estimates. Repository safety in the operational phase: the radiation protection for the operational personnel, safeguards related questions, and criticality during the operational phase were analysed. Long-term safety of the repository: here special aspects of the geochemistry in clay were considered as well as basics for demonstrating the

  13. Swelling clay pellets. Elaboration and characterization

    International Nuclear Information System (INIS)

    Sealing structure, used in deep radioactive waste disposal, must prevent the radionuclides to diffuse to the biosphere. The main asset of pellets is their easy put in place. Yet porosity of such structures is higher and the swelling pressure lower in the structure performed with compacted blocks. As at such depth, hydraulic pressure could reach several MPa, the first goal of the study was to demonstrate that such a pressure does not alter the swelling pressure. A bibliographic study on the structural organisation of clayey media and stresses occurring in such media, associated to injection tests with high water pressure, has allowed- to validate the effective stress concept in saturated swelling clays and so to show that hydraulic pressure are not restrictive for using pellets. Different processes have also been studied to produce pellets: all of them give pellets with sizes around 20 mm and dry density higher than 1,90 g/cm3. Nevertheless, soaking test emphasised that porosity between pellets is to high to get a swelling pressure. Two approaches was then adopted to decrease this porosity: (i) mixing pellets with different sizes and (ii) mixing pellets with powder. In the first case, numerical calculation points out that, according to the processes, it would be better to use at least three different sizes to get the right porosity. in the second case, the introduction of pellets in the samples brings a new scale in the structural organisation (layer - particle - aggregate- pellet) in such a way that phenomena are more emphasized in the mixtures. Nevertheless, whatever the medium is like, the decrease of the axial and radial stresses during hydration is due to the decrease simultaneously to the increase of the swelling pressure. Finally, at same homogenized dry density heterogeneous and homogeneous samples have quite the same hydrodynamic and hydro-mechanical properties. That's why, it is suggested to describe heterogeneous media behaviour with modelling based on

  14. 44th Journées des Actinides and 10th SPCA. Scientific Programme and Abstracts

    International Nuclear Information System (INIS)

    In the opening Session for the 10th SPCA the program of the school will be presented.The sessions of the 10th SPCA are: Physics, Chemistry,Theory, electronic structure,Nuclear forensics, Measuring systems. While the 10th SPCA lectures on crystallography, Physics, Chemistry and basics of actinides research

  15. Polyimide-Clay Composite Materials for Space Application

    Science.gov (United States)

    Orwoll, Robert A.; Connell, John W. (Technical Monitor)

    2005-01-01

    The introduction of nanometer-sized clay particles into a polyimide matrix has been shown to enhance the physical properties of specific polymer systems. The clay comprises large stacked platelets of the oxides of aluminum and silicon. These sheets have long dimensions on the order of tenths of a micrometer and thicknesses of several nanometers. Homogeneous dispersion of the clay platelets in the polymer matrix is necessary to achieve those enhancements in polymer properties. Natural montmorillonite with the empirical formula Na0.33Mg0.33Al1.67(OH)2(Si4O10) contains exchangeable inorganic cations. The clay lamellae stack together with the positive sodium ions situated between the surfaces of the individual sheets to balance negatively charged oxygen atoms that are on the surfaces of the sheets. These surface charges contribute to strong electrostatic forces which hold the sheets together tightly. Exfoliation can be accomplished only with unusual measures. In preparing clay nanocomposites, we have taken two steps to try to reduce these interlamellar forces in order to promote the separation (exfoliation) of the sheets and the dispersion of the individual clay particles throughout the organic polymer matrix. In the first step, some of the surface Na(+) ions are replaced with Li(+) ions. Unlike sodium cations, the lithium cations migrate into the interior of the lamellae when the system is heated. Their departure from the surface reduces the surface charge and therefore the attractive forces between the sheets. The loss of alkali metal cations from the surface can be measured as the cation exchange capacity (CEC) of the clay. For example, we found that the CEC of montmorillonite clay was reduced by almost two thirds by treating it with lithium ions and heating to 250 C for 24 hr. Lesser heating has a smaller effect on the CEC. X-ray diffraction measurements show that the d-spacing decreased from ca. 1.34 to 0.97 nm, apparently a consequence of a collapse of the clay

  16. Photophysics of Auramine O adsorbed on solid clays

    International Nuclear Information System (INIS)

    The dye loading effect on the photophysical behavior of Auramine O adsorbed onto solid clays was studied. When the dye concentration is increased, solid samples of Auramine O incorporated in SYn-1, SAz-1 and SWy-1 clays show an enhancement of the β-band in the UV–vis-DR spectra and the band at 450 nm shifts to the blue. This behavior can be attributed to the formation of H-type dye aggregates. For SYn-1 and SAz-1 clays, which show higher charge density, the formation of H-aggregates of the dye is favored. The fluorescence intensity and lifetime values of AuO decrease with the increasing of dye loading in these clays, since H aggregates do not exhibit fluorescence. The basal spacing of SAz-1 and SYn-1 containing 5% of AuO remains the same as that for pure SAz-1 and SYn-1. The adsorption of the dye predominantly occurs on the external surface of the SAz-1 and SYn-1 clays. On the other hand, for SWy-1 clay, UV–vis results suggest the presence of H- and J- aggregates. The fluorescence emission and lifetimes increase with the AuO concentration. XRD measurements confirm the penetration of the Auramine O into interlayer regions of the SWy-1 clay. When the Auramine is in the interlamellar regions of clay, the rotation of its phenyl rings is restricted, diminishing the internal conversion rate, therefore increasing the emission. The adsorption of the dye occurs on the external surface and in the interlamellar layers of SWy-1. - Highlights: • AuO incorporated in SYn-1, SAz-1 and SWy-1 shows formation of H-aggregates. • The formation of H-aggregates of the dye is favored in SYn-1 and SAz-1 clays. • Adsorption of the dye occurs on the external surface of SAz-1 and SYn-1. • Auramine O penetrates into the interlayer regions of the SWy-1. • Fluorescence emission increases for AuO in the interlayer regions

  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. Clay fraction mineralogy of a Cambisol in Brazil

    International Nuclear Information System (INIS)

    Clay minerals having a 2:1 (tetrahedral:octahedral sheet) structure may be found in strongly weathering soils only if the local pedo-climatic environment prevents them from further weathering to other minerals such as iron oxides. The clay minerals impart important chemical properties to soils, in part by virtue of changes in the redox state of iron in their crystal structures. Knowing the chemical nature of soil clays is a first step in evaluating their potential reactivity with other soil constituents and processes, such as the chemical decomposition of organic substrates to be potentially used in environmental remediation. The purpose of this work was to characterize the iron oxides and iron-bearing clay minerals from a B horizon of a Cambisol developed on tuffite in the State of Minas Gerais, Brazil, using chemical analysis, powder X-ray diffraction, Moessbauer spectroscopy, and thermal analysis. The iron oxides of this NaOH-treated clay-fraction were found to contain mainly maghemite (γFe2O3) and superparamagnetic goethite (αFeOOH). Kaolinite (Al2Si2O5(OH)4), smectite, and minor portions of anatase (TiO2) were identified in the CBD-treated sample.

  19. 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.

  20. Organo-clay/anthracite filtration for oil removal

    International Nuclear Information System (INIS)

    An advantage of organo-clay compared to other sorbents is that it can selectively remove organic pollutants from contaminated waters. An investigation was conducted to determine the potential of an organo-clay/anthracite mixture as a filter media for the removal of oil from synthetic and real oily waters. Also included in the study were column filtration studies using synthetic and real waste waters to determine the sorptive capacity of the material. In general, oil removal efficiencies in a 300 mm organo-clay/anthracite bed decreased with an increase in flow rates. Results of eight hour studies indicated that the depth of an organo-clay/anthracite bed has a direct effect on oil removal efficiency. The Thomas equation provides a reasonable fit of the data based on breakthrough studies. The model can be used to determine the parameters needed to design full-scale filtration columns. The uptake of oil by an organo-clay/anthracite mixture is well described by an equation including time such as the Weber or Moris model. The maximum solid-phase concentration of the solute values obtained from the Thomas equation were comparable to the values found by a mass balance approach. 12 refs., 8 figs., 4 tabs

  1. Cesium sorption and desorption behavior of clay minerals

    International Nuclear Information System (INIS)

    Cesium sorption and desorption of clay minerals (montmorillonite, beidellite, nontronite, weathered biotite, rectorite and illite) were investigated by consecutive sorption-desorption (CSD) experiments. In batch sorption experiment, two solutions with different Cs concentration 10-3 and 10-7 mol/L) were used. In batch desorption experiments, Cs sorbed samples in sorption experiments were treated 5 times with 1 mol/L ammonium acetate solution. In the case of CSD experiments using 10-3 mol/L Cs solution, the exchangeable cations (Na, Ca, and K) in the clay samples affected to the sorption ratio of Cs, and this effect depended on the type of clay mineral. The desorption ratios of untreated, Na-exchanged and Ca-exchanged weathered biotite ranged from 23 to 33%, while that of other samples was over 80%. In the case of CSD experiments using 10-7 mol/L Cs solution, the sorption ratio of montmorillonite was smaller than that of the other clay samples. In desorption experiments, more than 10-9 mol sorbed Cs remained in 1.0 g of the sample after 5 extraction times. These results indicate that all examined clay samples are able to strongly adsorb Cs with a capacity of more than 10-9 mol/g. (author)

  2. Waste disposal concept in a tertiary clay formation

    International Nuclear Information System (INIS)

    Investigations on the suitability of tertiary clay layer as host formation for disposal of conditioned high-level and alpha bearing radioactive waste were started in Belgium in the mid-seventies. On the basis of results obtained from preliminary field and laboratory research it was possible at the end of the seventies to elaborate a first rough outline of an underground facility for final emplacement of the waste concerned. Excellent retention capacity for most of the long-lived radionuclides and low hydraulic conductivity are found in the Boom clay formation in the investigated area. In the early stage of the program, however, uncertainties remained about the possibility of creating galleries at reasonable depth in clay at an acceptable cost price. Therefore, the decision was taken in 1978 to build an underground laboratory in order to investigate, among others, the geotechnical properties and the minability of the Boom clay. A satisfactory reproduction of three years of in-situ measurements was obtained by using an elasto-viscoplastic model with strain softening. The main conclusion of this R and D program, is that tunneling capabilities at reasonable cost prices in deep laying Boom clay have been demonstrated

  3. Characterization of edible clay (multani mitti) using INAA (abstract)

    International Nuclear Information System (INIS)

    Multani Mitti is basically clay commonly used in cosmetics, medicines. It is also used for cleansing of body and hair and eating specially women (pregnant and lactating) and children. 16 Essential major, minor and trace elements (Ba, Co, Cr, Cs, Fe, K, Mg, Mn, Mo, Na, Rb, Se Sr, Ti, V and Zn) have been determined in Multani Mitti (MM) clay using instrumental neutron activation analysis (INAA) technique were studied in collected clay samples from Rakhi Gaj located 40 Km from D. G. Khan, Pakistan. These samples were analyzed by Instrumental Neutron Activation Analysis (INAA) to detect the elemental hazard assessment. Radioassay schemes for three sets of elements after neutron irradiation and cooling were evolved to avoid matrix effects. The composition of MM clay shows major elements in descending order as Fe > K > Mg > Na > Mn > Zn > V > Rb > Cr >Ba followed by minor elements as Sr >Co > Cs with trace levels of Se. Data have been compared with clays available in literature globally. Intakes of essential elements were calculated for pregnant, lactating women and children. Intakes were found comparable to WHO levels except Fe and Cr. Risk assessment was measured using mathematical model. The quality assurance of data was performed using Standard Reference Materials (SRMs) of a similar matrix (IAEA Lake sediment SL-1 and IAEA Soil S-7). (author)

  4. 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)

  5. Morphological Evaluation of Variously Intercalated Pre-baked Clay

    Directory of Open Access Journals (Sweden)

    Ullah Hameed

    2014-06-01

    Full Text Available The use of porous materials is enjoying tremendous popularity and attention of the advance scientific communities due to their excellent adsorptive and catalytic activities. Clays are one of the most important candidates in the porous community which shows the above mentioned activities after modifing with a different intercalating agent. The paper is focused on the infiuence of some inorganic intercalating agents (NaOH on the morphology of the variously intercalated clay samples. The alkali metal was used as the inorganic intercalating agent. The effect of intercalation temperature, intercalation agent concentration and intercalation time on the pre-baked clay morphology were also part of the study. Scanning electron microscopy (SEM study was performed to evaluate the morphological changes of the resultant intercalates. Different morphological properties were improved significantly in the case of the inorganically modified clay samples. Thus, such intercalations are suggested to be effective if the clays under study are to be used for different industrial process at elevated conditions.

  6. Preparation and Characterization of Acid and Alkaline Treated Kaolin Clay

    Directory of Open Access Journals (Sweden)

    Sachin Kumar

    2013-06-01

    Full Text Available Kaolin was refluxed with HNO3, HCl, H3PO4, CH3COOH, and NaOH of 3M concentration at 110 °C for 4 hours followed by calcination at 550 °C for 2 hours. The physico-chemical characteristics of resulted leached kaolinite clay were studied by XRF, XRD, FTIR, TGA, DTA, SEM and N2 adsorption techniques. XRF and FTIR study indicate that acid treatment under reflux conditions lead to the removal of the octahedral Al3+ cations along with other impurities. XRD of acid treated clay shows that, the peak intensity was found to decrease. Extent of leaching of Al3+ ions is different for different acid/base treatment. The acid treatment increased the Si/Al ratio, surface area and pore volume of the clay. Thus, the treated kaolin clay can be used as promising adsorbent and catalyst supports. © 2013 BCREC UNDIP. All rights reservedReceived: 1st March 2013; Revised: 9th April 2013; Accepted: 19th April 2013[How to Cite: Kumar, S., Panda, A. K., Singh, R.K. (2013. Preparation and Characterization of Acids and Alkali Treated Kaolin Clay. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 61-69. (doi:10.9767/bcrec.8.1.4530.61-69][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4530.61-69] |View in  |

  7. 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.

  8. 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

  9. {alpha}-Pinene conversion by modified-kaolinitic clay

    Energy Technology Data Exchange (ETDEWEB)

    Volzone, C. [CETMIC-Centro de Tecnologia de Recursos Minerales y Ceramica-(CONICET-CIC), C.C. 49, Cno. Centenario y 506 (1897) M.B. Gonnet, Prov., Buenos Aires (Argentina)]. E-mail: volzcris@netverk.com.ar; Masini, O. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Comelli, N.A. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Grzona, L.M. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Ponzi, E.N. [CINDECA (CONICET-UNLP) calle 47 No. 257 (1900) La Plata, Prov., Buenos Aires (Argentina); Ponzi, M.I. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina)

    2005-10-15

    The isomerization of {alpha}-pinene using natural kaolinitic clay before and after different treatments was studied in this work. The kaolinite is a clay material constituted by phyllosilicate 1:1 layer (one sheet of tetrahedral silicon and one sheet of octahedral alumina). The clay was treated at different times using 6.0 N solution of sulfuric acid previous heating to 500 or 700 K. The materials were characterized by X-ray diffraction, by chemical analyses and acidity measurements. The catalytic reactions were carried out at 373 K in a reactor batch with condenser and stirrer. Samples were taken at regular intervals, and reactants and products were quantitatively analyzed with a gas chromatograph after separation of the individual compounds. Conversions of alpha pinene between 67 and 94%, and selectivities in camphene and in limonene of 65 and 23%, respectively, were obtained with the clay treated at different conditions. The structural and textural changes of the clay by the treatments influenced on catalytic reactions.

  10. Force field development for molecular dynamics simulations of clay minerals

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Clay minerals and their interfaces with aqueous solutions play an important role in many subsurface processes, including the retention and transport of aqueous species. Molecular simulations provide atomistic details of structural and dynamic properties of these fine-grained minerals that are difficult to obtain experimentally. Our research focus has been classical simulations of bulk clay minerals and their basal surfaces and interfaces using the fully flexible Clayff energy force field. Clayff is compatible with other force fields based on electrostatic and van der Waals interactions, permitting the study of a wide range of inorganic and organic solute at clay interfaces. Trends in clay swelling and ion adsorption onto the basal surfaces of clays are accurately described using this force field approach. Adsorption at pH-dependent edge sites is beyond the original scope of Clayff but is critical to a complete understanding of radionuclide transport near radioactive waste repositories. The application of Clayff to such edge sites requires three-body angle bend terms, and our recent work has involved parameterizing the hydroxylated edge site species (Mg-O-H, Al-O-H, and Si-O-H) found in end member models. (authors)

  11. Clay fraction mineralogy of a Cambisol in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Anastacio, A. S.; Fabris, J. D., E-mail: jdfabris@ufmg.br [Federal University of Minas Gerais, Campus - Pampulha, Department of Chemistry (Brazil); Stucki, J. W. [Department of Natural Resources and Environmental Sciences (United States); Coelho, F. S.; Pinto, I. V. [Federal University of Minas Gerais, Campus - Pampulha, Department of Chemistry (Brazil); Viana, J. H. M. [Embrapa Milho e Sorgo (Brazil)

    2005-11-15

    Clay minerals having a 2:1 (tetrahedral:octahedral sheet) structure may be found in strongly weathering soils only if the local pedo-climatic environment prevents them from further weathering to other minerals such as iron oxides. The clay minerals impart important chemical properties to soils, in part by virtue of changes in the redox state of iron in their crystal structures. Knowing the chemical nature of soil clays is a first step in evaluating their potential reactivity with other soil constituents and processes, such as the chemical decomposition of organic substrates to be potentially used in environmental remediation. The purpose of this work was to characterize the iron oxides and iron-bearing clay minerals from a B horizon of a Cambisol developed on tuffite in the State of Minas Gerais, Brazil, using chemical analysis, powder X-ray diffraction, Moessbauer spectroscopy, and thermal analysis. The iron oxides of this NaOH-treated clay-fraction were found to contain mainly maghemite ({gamma}Fe{sub 2}O{sub 3}) and superparamagnetic goethite ({alpha}FeOOH). Kaolinite (Al{sub 2}Si{sub 2}O{sub 5}(OH){sub 4}), smectite, and minor portions of anatase (TiO{sub 2}) were identified in the CBD-treated sample.

  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. Argilas especiais: o que são, caracterização e propriedades Special clays: what they are, characterization and properties

    OpenAIRE

    ANTONIO C. VIEIRA COELHO; Pérsio de Souza Santos; Helena de Souza Santos

    2007-01-01

    Special clays are a group of clays different from the large volume of clay mineral products named "Industrial Clays": kaolins, ball clays, refractory clays, bentonites, fuller's earths, common clays. Two groups of special clays exist: rare, as in the case of hectorite and sepiolite and restricted areas, as in the case of white bentonite, halloysite and palygorskite (attapulgite). A review is given of the most important producers of the special clays and their properties in the Western World, ...

  14. Influence of non-clay minerals on the interaction between metallic iron and Callovo-Oxfordian clay fraction

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste, it is of prime importance to understand the interaction mechanisms between the geological matrix, Callovo-Oxfordian clay rock (COx) and metallic iron, from the package overpack. In order to evidence the individual role of each clay component entering in the mineralogy of the COx, interactions between metallic iron and pure clays (smectites, illite and kaolinite) were first conducted. To investigate the role of the other minerals, the reactivity of COx, COx clay fraction (COxCF) and mixtures between COxCF and quartz, calcite or pyrite, was studied. Clays and additional minerals were put in contact with powder metallic iron with a weight ratio iron:clay fixed at 1:3 and a clay:solution ratio of 1:20. Proportions of non-clay minerals were deduced from the average COx composition: 50% clays, 24.5% quartz, 24.5% calcite and 1% pyrite. Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L-1, CaCl2 0.04 M.L-1) in Parr reactors for durations of one, three or nine months. After reaction, solid and liquid phases were separated by centrifugation and characterized by classical techniques combining chemical analyses (liquid analyses, transmission electron microscopy combined with Energy Dispersive of X-rays spectroscopy TEM-EDS), mineralogical (X-ray diffraction), spectroscopic (57Fe Moessbauer) and morphometric techniques (TEM, scanning electron microscopy and N2 adsorption). For COx, COxCF and all the pure clay phases, major evolutions were observed during the first month, which shows that the oxidation of metallic iron is rapid in our experimental conditions. Release of iron cations in solution, pH increase (8-10) and Eh decrease (reductive conditions) are responsible for the partial dissolution of initial clay phases. Released iron is involved in the crystallization of Fe

  15. Clay ground in paintings: from Northern to Southern Europe

    DEFF Research Database (Denmark)

    Buti, David; Vila, Anna; Haack Christensen, Anne; Filtenborg, Troels Folke; Ludvigsen, Loa; Dalby, Kim Nicole; Wadum, Jørgen

    constituent in paintings has still not been much investigated, neither with regard to the processing nor the trade of the material. Did it give a particular colour/structure in order to achieve a specific final effect of the painted surface? Was clay cheaper than chalk, calcium sulphate or earth pigments? Did...... it give more flexibility to the painting support? Was it connected to the tile industry? Was it a waste/reuse from the ceramic production? To better understand the role of clay ground as a material and its influence on painting techniques, a number of Danish and Italian 17th century paintings from......-based compounds. The investigation is demonstrating how widespread the use was of clays as constituent in paintings when comparing the analytical results performed on artworks from Northern and Southern Europe. This preliminary study will lead to further research focused on the link between artistic schools of...

  16. Clay-based materials for engineered barriers: a review

    International Nuclear Information System (INIS)

    The potential importance of backfilling and plugging in underground radioactive waste repositories has led different research institutions to carry out extensive studies of swelling clay materials for the development of engineered barriers in underground conditions. These materials should combine a variety of hydro-thermo-mechanical and geochemical properties: impermeability, swelling ability in order to fill all void space, heat transfer and retention capacity for the most noxious radionuclides. Smectite clays best exhibit these properties and most of the research effort has been devoted to this type of materials. In this paper, mineralogical composition, sodium or calcium content, thermo-hydro-mechanical properties, swelling pressure, hydraulic and thermal conductivity, and chemical properties of five smectite clays selected by five major nuclear countries are reviewed: Avonseal montmorillonite (Canada), MX 80 montmorillonite (Sweden), Montigel montmorillonite (Switzerland), S-2 montmorillonite (Spain), and Fo-Ca inter stratified kaolinite/beidellite (France). (J.S.). 29 refs., 5 figs., 3 tabs

  17. Evaluation methods for ceramic suitability of raw clays

    Directory of Open Access Journals (Sweden)

    Hajjaji M.

    2013-09-01

    Full Text Available Ceramic suitability of kaolinitic-illitic and chloritic-illitic raw clays was assessed by methods involving microstructure investigation and ceramic properties measurements, some reported diagrams and response surface methodology (RSM. Results of the former method showed that all clays are suitable for red stoneware tiles. The stoneware manufacturing is facilitated by the marked reduction of porosity due to the flow of melt, mainly originated from the breakdowns of illite. This result was partially supported by the use of a diagram involving the chemical composition of clays as well as by the RSM results. According to the later method, bricks may be manufactured under restricted firing conditions and stoneware tiles could be prepared at temperatures as low as 950°C.

  18. Clay-based polymer nanocomposites: research and commercial development.

    Science.gov (United States)

    Zeng, Q H; Yu, A B; Lu, G Q; Paul, D R

    2005-10-01

    This paper reviews the recent research and development of clay-based polymer nanocomposites. Clay minerals, due to their unique layered structure, rich intercalation chemistry and availability at low cost, are promising nanoparticle reinforcements for polymers to manufacture low-cost, lightweight and high performance nanocomposites. We introduce briefly the structure, properties and surface modification of clay minerals, followed by the processing and characterization techniques of polymer nanocomposites. The enhanced and novel properties of such nanocomposites are then discussed, including mechanical, thermal, barrier, electrical conductivity, biodegradability among others. In addition, their available commercial and potential applications in automotive, packaging, coating and pigment, electrical materials, and in particular biomedical fields are highlighted. Finally, the challenges for the future are discussed in terms of processing, characterization and the mechanisms governing the behaviour of these advanced materials. PMID:16245517

  19. Chemical evolution. XL - Clay-mediated oxidation of diaminomaleonitrile

    Science.gov (United States)

    Ferris, J. P.; Hagan, W. J., Jr.; Alwis, K. W.; Mccrea, J.

    1982-01-01

    The inhibition of the oligomerization of HCN by montmorillonite clays is shown to be caused by oxidation of diaminomaleonitrile (DAMN) by ferric ion in the clay lattice, with ferrous ion and oxalic acid the reaction products. It is demonstrated that diiminosuccinonitrile is the initial reaction product and is rapidly hydrolized to oxalic acid and HCN. The same oxidative transformations are effected by ferric ion bound to Dowex 50, ferric ion in solution, and Ni(NH3)6(2+). The rate of reaction of DAMN indicates no catalytic role for the clay in the oxidation of DAMN, and little reaction of the latter was observed with montmorillonite in which the bulk of the iron was in the divalent state. The possible significance of these redox reactions to chemical evolution is discussed.

  20. Use of modified clay materials in toluene conversion

    International Nuclear Information System (INIS)

    Clay materials, montmorillonite from Maghniya deposits (Algeria), were used as an acidic catalyst in toluene conversion. Toluene disproportionation reaction in gaseous phase was used. These clays were modified by ion exchange with uranyl ions UO22+. The surface acidity of catalysts was determined by the stepwise desorption technique (STD) of probe molecules using butylamine and ammonia. Thus, total acidity and distribution of the acidity strength were determined. The results show that materials presented an appreciable total acidity and catalytic activity in studied reaction. The acidity strength of catalysts due to UO22+ ions was kept at a temperature of 550 C. A relationship was found between the catalytic activity and acidity strength generated by the introduction of uranyl ions in the clay structure. (authors)

  1. Sawdust-clay-cement-plastic composite prepared by gamma irradiation

    International Nuclear Information System (INIS)

    A new material of sawdust-clay-cement-plastic composite has been prepared by impregnation of unsaturated polyester resin with different parts of styrene and methyl methacrylate (MMA) monomers into the void space of completely dried and molded specimens followed by exposure to Co-60 gamma radiation to induce graft copolymerization of the impregnated monomers onto the sawdust-clay-cement matrix. For each monomer mixture, suitable impregnation time and the radiation dose has been determined. High compression strength and bending modulus of specimens show that this material is comparable with high strength concrete. The hydration of sawdust-clay-cement matrix after molding for 1 up to 28 days shows that hydration products which deposited within the pore-spaces, decrease the porosity of the composite. The effect of the polymer loading content, as affected by the porosity, on mechanical properties is more effective than hardening of cement portion after hydration

  2. Nafion–clay nanocomposite membranes: Morphology and properties

    KAUST Repository

    Herrera Alonso, Rafael

    2009-05-01

    A series of Nafion-clay nanocomposite membranes were synthesized and characterized. To minimize any adverse effects on ionic conductivity the clay nanoparticles were H+ exchanged prior to mixing with Nafion. Well-dispersed, mechanically robust, free-standing nanocomposite membranes were prepared by casting from a water suspension at 180 °C under pressure. SAXS profiles reveal a preferential orientation of Nafion aggregates parallel to the membrane surface, or normal plane. This preferred orientation is induced by the platy nature of the clay nanoparticles, which tend to align parallel to the surface of the membrane. The nanocomposite membranes show dramatically reduced methanol permeability, while maintaining high levels of proton conductivity. The hybrid films are much stiffer and can withstand much higher temperatures compared to pure Nafion. The superior thermomechanical, electrochemical and barrier properties of the nanocomposite membranes are of significant interest for direct methanol fuel cell applications. © 2009 Elsevier Ltd. All rights reserved.

  3. Characterization of clay of Vitoria da Conquista - BA - Brazil

    International Nuclear Information System (INIS)

    Kaolinitic clays are vastly used in ceramic industry. Kaolinitic clay that are not coloured after firing are very useful in the production of ceramics because of their aesthetic aspect after firing. In this work clay material from Vitoria da Conquista (South- West Bahia, Brazil) was characterized by several techniques. The differential Scanning Calorimetry (DSC) shows a kaolinite characteristic curve with an endothermic peak at 492 deg C, which corresponds to the kaolinite - metakaolinite transformation. The transformation of alpha to beta quartz characterized by a 573 deg C peak was also observed in DSC. The samples were also characterized by water absorption and x rays powder diffraction. The 1100 deg C burned samples were tested by flexural strength. (author)

  4. Exploration of ceramic clays in the countryside of Cordoba (Spain)

    International Nuclear Information System (INIS)

    This paper deals with some aspects of the mining prospection of clays in the South of Cordoba (Spain). That studied clays are used as raw materials in a processing plant of ceramic products. In this ground characterisation for future mining operations, low proportion of carbonated materials was searched. To carry out the study, three seek areas were defined, each one of them of about 4 Km2, where two geophysical methods were applied (Electrical Resistivity Tomography and Vertical Electrical Sounding). X-ray diffraction, EDAX, direct cut, compaction, swelling and bearing capacity tests, among others, were carried out in samples picked up in each seek area. Using the information provided by all these tests the most interesting areas for the exploitation defined. These studies resulted in the selection of new interesting deposits for the clay industry. (Author)

  5. Effects of natural heating on a clay formation

    International Nuclear Information System (INIS)

    As a contribution to the characterization of clay deposits as possible sites for nuclear waste disposal, the metamorphic effects induced on Pliocene argillaceous sediments by the small subvolcanic body of Orciatico (Tuscany, Italy) were investigated. In areas close to marginal facies of the magmatic body, where temperatures were presumably ranging from 100 to 5000C, the thermo-metamorphic aureole thickness doesn't exceed 2 meters. In this zone the clay fraction (45-69% of the bulk rock) changes from an illite+illite/smectite interstratified+vermiculite+chloritic intergrades assemblage to a paragenesis characterized only by illite+smectite, the later being the most stable phase among the clay minerals. Within such zone alkalis (Na,K, and Rb) and alkaline-earths (Ca and Sr) result to be the most highly mobilized elements

  6. Effects of Fiber Reinforcement on Clay Aerogel Composites

    Directory of Open Access Journals (Sweden)

    Katherine A. Finlay

    2015-08-01

    Full Text Available Novel, low density structures which combine biologically-based fibers with clay aerogels are produced in an environmentally benign manner using water as solvent, and no additional processing chemicals. Three different reinforcing fibers, silk, soy silk, and hemp, are evaluated in combination with poly(vinyl alcohol matrix polymer combined with montmorillonite clay. The mechanical properties of the aerogels are demonstrated to increase with reinforcing fiber length, in each case limited by a critical fiber length, beyond which mechanical properties decline due to maldistribution of filler, and disruption of the aerogel structure. Rather than the classical model for reinforced composite properties, the chemical compatibility of reinforcing fibers with the polymer/clay matrix dominated mechanical performance, along with the tendencies of the fibers to kink under compression.

  7. Delaminated clays and their use in hydrocarbon conversion processes

    International Nuclear Information System (INIS)

    A process for preparing a delaminated clay having an X-ray diffraction pattern which does not contain a first order reflection, is described, which comprises: (a) reacting a natural or synthetic swelling clay with a reactant selected from the group consisting of coloidal silica particles, colloidal alumina particles, colloidal titania particles, colloidal chromia particles, colloidal tin oxide particles, colloidal antimony oxide particles, cationic molybdenum clusters, cationic tungsten clusters, cationic nickel clusters, cationic cobalt clusters and mixtures thereof to form a flocculated reaction product, and (b) drying the flocculated reaction product in the presence of air to form the delaminated clay having an X-ray diffraction pattern which does not contain a first order reflection

  8. Selenite reduction in Boom clay: Effect of FeS2, clay minerals and dissolved organic matter

    International Nuclear Information System (INIS)

    Several experiments were set up to study Se speciation and solubility in the reducing Boom clay environment, starting from oxidized Se species which were added in oversaturation with respect to the thermodynamic solubility of reduced Se solid phases. Upon introduction of SeO32- to FeS2-containing samples, adsorption of SeO32- occurred at the FeS2 surface, and led to a reduction and precipitation of a Se0 solid phase with a solubility of 3x10-9 M (after 60 days). In the presence of humic substances, an association of Se with these humic substances was observed and the 3x10-9 M solubility limit was not reached in the same time delay. Upon introduction of SeO32- to Boom clay suspensions (equilibration up to 9 months), the initial adsorption of SeO32- on the solid phase was increased with respect to systems containing only FeS2, due to the presence of (illite) clay minerals. This competing adsorption process, and the presence of humic substances, again decreased the kinetics of reduction with respect to FeS2 samples. Also, an association of Se with Boom clay humic substances was observed, and amounted up to ∼10-7 M in some samples after 9 months equilibration. - Selenite reduction by FeS2 is kinetically controlled, with clay minerals and organic matter playing an important role

  9. Influence of clay concentration on the morphology and properties of clay-epoxy nanocomposites prepared by in-situ polymerization under ultrasonication

    Institute of Scientific and Technical Information of China (English)

    Jinwei Wang; Xianghua Kong; Lei Cheng; Yedong He

    2008-01-01

    To investigate the effect of clay concentration on the structures and properties of bispbenol-A epoxy/nanoclay composites,three composites with organoclay concentrations of 2.5wt%, 5wt%, and 7.5wt% of the epoxy resin were prepared by in-sire polym-erization under mechanical stirring followed by ultrasonic treatment. The clay aggregates on micro-scale indicate the absence of fully exfoliated nanocomposites. The layer space decreases with the increase of clay concentration, which suggests that the exfoliation would be constrained if more clay is added as the ultrasonic force is exerted. The thermal decomposition temperature remains almost unchanged with the increase of clay concentration. The glass transition temperature of the composites decreases slightly with the in-crease of clay concentration, whereas the storage modulus increases with the increase of clay concentration.

  10. Sorption of radionuclides on some clays and soils

    International Nuclear Information System (INIS)

    The sorption and desorption properties of radio- cesium, barium and iodine were studied using clay and soil fractions from various regions of Turkey. Clay minerals and soil fractions were identified by X-ray diffraction spectrometry and particle size distribution experiments. The clay minerals were found to be kaolinite, montmorillonite and mixed chlorite-illite types. Grain sizes of all solid particles were all -8 mols/L to 10-3 mols/L. The radionuclides 137Cs, 90Sr, 133Ba and 125I were used as tracers. Batch experiments were performed to determine the distribution ratio, RD, as a function of interaction time, shaking rate, ion concentration, pH, and volume/mass ratio. Cation exchange capacities were obtained using the silver-thiourea method. Kinetic studies indicated initial rapid sorption gradually reaching saturation in several days. The saturation time ranged from 6 to 12 days depending on clay as well as radionuclide types. Inverse S-shaped loading curves were obtained in the studies of RD versus cation concentration on the solid. The curves suggest the presence of at least two types of sorption sites on the clay minerals. The sorption process was observed to be reversible to a large extent in all cases. The distribution ratio was found to increase with increasing volume/mass ratio and with decreasing particle size. The latter observation suggests mainly surface sorption. Generally highest RD values were observed for cesium sorption followed by strontium and barium. Iodine was sorbed very little by clay minerals. (16 refs., 7 figs., 3 tabs.)

  11. Productivity of clay tailings from phosphate mining: I. Biomass crops

    International Nuclear Information System (INIS)

    Phosphate mining in Florida has waste products of phosphatic clay and quartz sand tailings, each making up about one-third of the original matrix (PO4 ore, sand, and clay). Phosphatic clay ponds typically occupy about 50% of the mined sites and normally require 10 to 15 yr before 40 to 50% solids are obtained. These clays contain no phytotoxic materials and are high in most plant nutrients. When surface water has disappeared, these clays are classified as clayey Haplaquents. A split-plot field experiment was conducted to study biomass yield, quality, plant nutrient concentrations, changes in soil nutrients, and 226Ra. Seven biomass crops -(i) elephantgrass (Pennisetum purpureum L. PI 300086), (ii) leucaena [Leucaena leucocephala (Lam.) De Wet], (iii) alemangrass [Echinochloa polystachya (H.B.K) Hitch], (iv) erianthus [Erianthus arundinaceum (Retz) Jews IK 76-63'], (v) desmodium (Desmodium cinerascens A. Gray), (vi) sweet sorghum [Sorghum bicolor (L.) Moench USDA M 81E], and (vii) forage sorghum [Sorghum bicolor (L.) Moench Pioneer 931] - were grown on the phosphatic clay with and without a 5-cm surface layer of quartz sand tailings. Nitrogen was the only fertilizer element applied for grass species and no fertilizer was applied for legumes during the 4-yr period. Dry biomass yield averaged over 4 yr for erianthus, leucaena, and elephantgrass averaged 139.6, 58.5, and 56.5 Mg ha-1 yr-1, respectively. Crude protein and digestibility were low in mature, whole-plant samples except for leucaena (122.0 g kg-1). Generally, all whole plants contained adequate concentrations of nutrients. Mehlich-I-extractable soil nutrient concentrations changed little over the 4-yr period. Radium-226 concentration in plant tissue (0.23 pCi g-1) was nearly six times higher than the concentration measured in plants from an unmined surface Spodosol (0.04 pCi g-1)

  12. The influence of clay minerals on acoustic properties of sandstones

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Olav

    1997-12-31

    This thesis aims to provide better understanding of the relationship between the acoustic properties and the petrophysical/mineralogical properties in sand-prone rock. It emphasizes the influence of clay minerals. The author develops a method to deposit clay minerals/mineral aggregates in pore space of a rigid rock framework. Kaolinite aggregates were flushed into porous permeable Bentheimer sandstone to evaluate the effect of pore filling minerals on porosity, permeability and acoustic properties. The compressional velocity was hardly affected by the clay content and it was found that the effect of minor quantities of pore filling minerals may be acoustically modelled as an ideal suspension, where the pore fluid bulk modulus is modified by the bulk modulus of the clay minerals. The influence of clays on acoustic velocities in petroleum reservoir rocks was investigated through ultrasonic measurements of compressional- and shear-waves on core material from reservoir and non-reservoir units on the Norwegian Continental Shelf. The measured velocities decrease as the porosity increases, but are not strongly dependent on the clay content. The measured velocities are less dependent on the petrophysical and lithological properties than indicated by previous authors and published mathematical models, and stiffness reduction factors are introduced in two of the models to better match the data. Velocities are estimated along the wellbores based on non-sonic well logs and reflect well the actual sonic log well measurements. In some wells the compressional velocity cannot be modelled correctly by the models suggested. Very high compressional wave anisotropy was measured in the dry samples at atmospheric conditions. As the samples were saturated, the anisotropy was reduced to a maximum of about 30% and decreases further upon pressurization. Reservoir rocks retrieved from 2500 m are more stress dependent than those retrieved from less than 200 m depth. 168 refs., 117 figs., 24

  13. Environmental Hf-Nd isotopic decoupling in World river clays

    Science.gov (United States)

    Bayon, Germain; Skonieczny, Charlotte; Delvigne, Camille; Toucanne, Samuel; Bermell, Sylvain; Ponzevera, Emmanuel; André, Luc

    2016-03-01

    The hafnium and neodymium radiogenic isotope systems behave differently during Earth surface processes, causing a wide dispersion of Hf and Nd isotopic compositions in sediments and other sedimentary rocks. The decoupling between Hf and Nd isotopes in sediments is generally attributed to a combination of preferential sorting of zircon during sediment transport and incongruent weathering processes on continents. In this study, we analysed size-fractions of sediment samples collected near the mouth of 53 rivers worldwide to better understand the factors controlling the distribution of Hf and Nd isotopes in sediments. Our results for rivers draining old cratonic areas and volcanic provinces demonstrate that both granite and basalt weathering can lead to significant grain-size dependent Hf isotopic variability. While silt-size fractions mainly plot along the Terrestrial Array, World river clays are systematically shifted towards more radiogenic Hf isotopic compositions, defining together with published data a new Clay Array (ɛHf = 0.78 ×ɛNd + 5.23). The Hf-Nd isotope decoupling observed in volcanogenic sediments is best explained by selective alteration of Lu-rich mineral phases (e.g. olivine) and preferential enrichment of resistant unradiogenic minerals, such as spinel and ilmenite, in silt fractions. We also show that the extent to which World river clays deviate from the Clay Array (ΔɛHf clay) is not linked to the presence of zircons. Instead, it correlates positively with weathering indices and climatic parameters (temperature, rainfall) of the corresponding drainage basins. Overall, these findings demonstrate that the distribution of Hf-Nd isotopes in clay-size sediments is related to a large extent to weathering conditions on continents, although the precise mechanisms controlling this relationship remain unclear. We finally propose that the Hf-Nd isotope pair proxy could be used in palaeoenvironmental studies to provide semi-quantitative information on

  14. Clay content evaluation in soils through GPR signal processing

    Science.gov (United States)

    Tosti, Fabio; Patriarca, Claudio; Slob, Evert; Benedetto, Andrea; Lambot, Sébastien

    2013-10-01

    The mechanical behavior of soils is partly affected by their clay content, which arises some important issues in many fields of employment, such as civil and environmental engineering, geology, and agriculture. This work focuses on pavement engineering, although the method applies to other fields of interest. Clay content in bearing courses of road pavement frequently causes damages and defects (e.g., cracks, deformations, and ruts). Therefore, the road safety and operability decreases, directly affecting the increase of expected accidents. In this study, different ground-penetrating radar (GPR) methods and techniques were used to non-destructively investigate the clay content in sub-asphalt compacted soils. Experimental layout provided the use of typical road materials, employed for road bearing courses construction. Three types of soils classified by the American Association of State Highway and Transportation Officials (AASHTO) as A1, A2, and A3 were used and adequately compacted in electrically and hydraulically isolated test boxes. Percentages of bentonite clay were gradually added, ranging from 2% to 25% by weight. Analyses were carried out for each clay content using two different GPR instruments. A pulse radar with ground-coupled antennae at 500 MHz centre frequency and a vector network analyzer spanning the 1-3 GHz frequency range were used. Signals were processed in both time and frequency domains, and the consistency of results was validated by the Rayleigh scattering method, the full-waveform inversion, and the signal picking techniques. Promising results were obtained for the detection of clay content affecting the bearing capacity of sub-asphalt layers.

  15. Hydrothermal field test with french candidate clay embedding steel heater in the Stripa mine

    International Nuclear Information System (INIS)

    Field experiments with French kaolinite/smectite clay heated up to 170 degrees C in boreholes in granite were conducted for 8 months and 4 years. The clay heated for 8 months has a considerably higher water content and it had undergone much less changes in mineralogy and physical properties than the clay exposed to heating for 4 years. The drying of the latter clay was probably caused by hydrogen gas from corrosion of the heater. The clay next to the heater turned into clay-stone despite conversion of the kaolinite component to smectite. (42 refs)

  16. Differentiation of pleistocene deposits in northeastern Kansas by clay minerals

    Science.gov (United States)

    Tien, P.-L.

    1968-01-01

    Seventy-four samples from eight stratigraphic sections of lower Pleistocene glacial and glaciofluvial deposits in Doniphan County, extreme northeastern Kansas, were analyzed using X-ray diffraction techniques. Clay-mineral assemblages of the clay mineral associated with minor amounts of kaolinite and illite. An attempt was made to differentiate units of till and nontill deposits by using the relative intensities of 001 reflections of "mixed-layer mineral," kaolinite, and illite. At least two tills were recognizable. Associated nontill deposits, could not be differentiated from one another, although the nontills are easily distinguished from tills. ?? 1968.

  17. "Clay grounds” in Denmark: from soil to canvas

    DEFF Research Database (Denmark)

    Buti, David; Vila, Anna; Haack Christensen, Anne; Filtenborg, Troels Folke; Dalby, Kim Nicole; Wadum, Jørgen

    large decorative scheme showed that at least two grounds from those paintings consist mainly of clay mixed with iron and magnesium-containing compounds. Furthermore, both SEM-EDX and µRaman measurements clearly highlighted the presence of a large amount of quartz particles. It is well known that clay is...... a sheet silicate mineral and may contain variable amounts of water trapped in its structure and can occur with other phases including quartz and carbonates. Studies carried out by Kühn and Groen and summarized by the latter show that in the Netherlands this kind of preparation layer was first...

  18. Shampoo-Clay Heals Diaper Rash Faster Than Calendula Officinalis

    OpenAIRE

    Adib-Hajbaghery, Mohsen; Mahmoudi, Mansoreh; Mashaiekhi, Mahdi

    2014-01-01

    Background: Diaper rash is one of the most common skin disorders of infancy and childhood. Some studies have shown that Shampoo-clay was effective to treat chronic dermatitis. Then, it is supposed that it may be effective in diaper rash; however, no published studies were found in this regard. Objectives: This study aimed to compare the effects of Shampoo-clay (S.C) and Calendula officinalis (C.O) to improve infantile diaper rash. Patients and Methods: A randomized, double blind, parallel con...

  19. Anisotropy effects in a deep excavation in stiff clay

    OpenAIRE

    Vaunat, Jean; Gens Solé, Antonio; Barboza De Vasconcelos, Ramon

    2013-01-01

    This paper tackles the issues related to the excavation of a horizontal gallery carried out in Boom clay, a tertiary clay that hosts the Underground Laboratory of the Belgium Nuclear Agency (SCK-CEN). The gallery is 85 m long, 5 m wide and connects one of the laboratory access shafts to a horizontal drift drilled from the second access shaft. Displacement and pore water pressure sensors installed from both gallery ends allowed for a detailed monitoring of the hydro-mechanical response of the ...

  20. The geochemical behaviour of uranium in the Boom Clay

    OpenAIRE

    Delécaut, Grégory

    2004-01-01

    In Belgium, the Boom Clay is currently studied as the reference host formation for the disposal of high-level and long-lived radioactive waste. In case of direct disposal of spent fuel, uranium isotopes are important contributors along with their daughters to the dose rate at very long term. Therefore, it is essential to study the migration of uranium in the host formation. The present work contributes to improve the knowledge of uranium speciation in the Boom Clay, U(IV) versus U(VI), and of...

  1. Diffusion in clay - experimental techniques and theoretical models

    International Nuclear Information System (INIS)

    A large number of experiments have been carried out by this and adjacent research groups to assess the diffusivity of a wide variety of dissolved species such as cations anions, macromolecules and gases in watersaturated clay at differing compaction. The results have been reported in a series of KBS-technical reports. This report is a summary of the experiences gained by these experiments. Recommended experimental methods are described and a methodology to treat and interpret the experimental data is outlined. The mechanisms for diffusion in clay are also discussed in some detail - especially the influence of charge, molecular size and hydrolysis of the diffusing species. (author)

  2. Midwifery models: students' conceptualization of a midwifery philosophy in clay.

    Science.gov (United States)

    Walker, Deborah S

    2007-01-01

    Formulating a professional and personal philosophy statement assists nurses and midwives in clarifying focus and direction. It also facilitates grounding of the nursing and midwifery professions or professionals by enabling the identification of both shared beliefs and unique elements. The purpose of this activity was to assist beginning student nurse-midwives (SNMs) in exploring the intersection of their own and the profession's philosophy. Through the creation of a clay representation of their philosophical model, eight SNMs expressed their midwifery philosophies at the beginning of their clinical sequence by sculpting them in clay and then described their sculptures and how they exemplified their philosophies. PMID:17207753

  3. Radiation-induced defects in clay minerals: A review

    International Nuclear Information System (INIS)

    Extensive information has been collected on radiation effects on clay minerals over the last 35 years, providing a wealth of information on environmental and geological processes. The fields of applications include the reconstruction of past radioelement migrations, the dating of clay minerals or the evolution of the physico-chemical properties under irradiation. The investigation of several clay minerals, namely kaolinite, dickite, montmorillonite, illite and sudoite, by Electron Paramagnetic Resonance Spectroscopy has shown the presence of defects produced by natural or artificial radiations. These defects consist mostly of electron holes located on oxygen atoms of the structure. The various radiation-induced defects are differentiated through their nature and their thermal stability. Most of them are associated with a π orbital on a Si–O bond. The most abundant defect in clay minerals is oriented perpendicular to the silicate layer. Thermal annealing indicates this defect in kaolinite (A-center) to be stable over geological periods at ambient temperature. Besides, electron or heavy ion irradiation easily leads to an amorphization in smectites, depending on the type of interlayer cation. The amorphization dose exhibits a bell-shaped variation as a function of temperature, with a decreasing part that indicates the influence of thermal dehydroxylation. Two main applications of the knowledge of radiation-induced defects in clay minerals are derived: (i) The use of defects as tracers of past radioactivity. In geological systems where the age of the clay can be constrained, ancient migrations of radioelements can be reconstructed in natural analogues of high level nuclear waste repositories. When the dose rate may be assumed constant over time, the paleodose is used to date clay populations, an approach applied to fault gouges or laterites of the Amazon basin. (ii) The influence of irradiation over physico-chemical properties of clay minerals. An environmental

  4. Conducting polymer/clay nanocomposites and their applications.

    Science.gov (United States)

    Fang, Fei Fei; Choi, Hyoung Jin; Joo, Jinsoo

    2008-04-01

    This review aims at reporting on interesting and potential aspects of conducting polymer/clay nanocomposites with regard to their preparation, characteristics and engineering applications. Various conducting polymers such as polyaniline, polypyrrole and copolyaniline are introduced and three different preparation methods of synthesizing conducting polymer/clay nanocomposites are being emphasized. Morphological features, structure characteristics and thermal degradation behavior are explained based on SEM/TEM images, XRD pattern analyses and TGA/DSC graphs, respectively. Attentions are also being paid on conductive/magnetic performances as well as two potential applications in anti-corrosion coating and electrorheological (ER) fluids. PMID:18572558

  5. Clay as a barrier to radionuclide migration: a review

    International Nuclear Information System (INIS)

    Because of their low permeability, high sorption capacity and plasticity, clay bodies are potentially suitable repositories for radioactive waste. The paper discusses the factors that influence radionuclide mobility in natural clay materials. Methods for determining radionuclide migration rates are described and compared. Data requirements necessary to establish whether or not a particular site is suitable for waste disposal are discussed. Suggestions are made as to the most important generic research that needs to be carried out. In the appendix, some of the most relevant, published, sorption and diffusion data are summarised and compared. (author)

  6. Hydro-mechanical properties of the red salt clay (T4) - Natural analogue of a clay barrier

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Long-term storage of high-level radioactive waste in deep geologic formations is worldwide the only accepted solution to warranty long term safety. Besides clay and crystalline rocks, salt is one of the potential host-rock candidates, mainly favored in Germany. As salts rocks are highly soluble their barrier integrity against water inflow from the cap rock is questionable. Argillaceous cap rocks or intercalated clay layers may act as protective shield in the hanging wall above a repository, thus providing a multi-barrier system. The aims of our study are twofold: 1) to characterize the mineralogical, hydraulic and rock-mechanical properties of the so-called Red Salt Clay (T4) as natural analogue of a clay barriers represented by different states of induration corresponding to various depth of burial diagenesis; 2) to demonstrate the favoured barrier properties of an argillaceous layer in the top of a salt formation undergoing dynamic processes such as rock bursts. The so-called Red Salt Clay (T4) is deposited as clay rich clastic sediment at the base of the Aller-series forming a persistent lateral layer above the lower Zechstein-series. The thickness of the clay-formation becomes smaller with decreasing distance from the border of the basin, i.e. from ∼15 m at Rossleben, over 7 m at Bernburg to 3.5 m at Zielitz, all in Saxony-Anhalt, D). The mineralogical composition of the Red Salt Clay varies, e.g. average composition for the Teutschenthal area: clay minerals 54% (Chlorite: 8%; Illite/Muscovite: 46%); quartz: 22%; anhydrite: 15%; accessory gypsum; Halite: 6%, Hematite: ∼ 2%). The geochemical and mineralogical composition of the Red Salt Clay represents a final state of natural salt-clay-systems, thus standing as a natural analogue for bentonite-based sealing systems in contact with high-saline solutions (e.g. saturated NaCl-solution, solutions with various Mg2+ -, K+ -, SO42- - concentrations). The

  7. Smart Clays: SAFOD Samples Confirm the Key Role of Newly-formed Clays in Shallow Fault Zones

    Science.gov (United States)

    Schleicher, A.; van der Pluijm, B.; Warr, L. N.

    2013-12-01

    Analysis of fault rocks from drill-cores of the San Andreas Fault Observatory at Depth (SAFOD) project in Parkfield (CA) confirm our original hypothesis that active clay growth can occur locally at shallow conditions and that such clay localization affect fault mechanics and fault creep in particular. SAFOD fault rocks contain a variety of newly formed clay minerals including smectite, illite-smectite and chlorite-smectite, as well as illite and chlorite. Brecciated host rock fragments are abundantly coated by polished and/or striated thin-films of hydrated clay minerals, creating an interconnected and pervasive network of displacement surfaces. Ar encapsulation dating of mixed-layer nanocoatings demonstrates recent crystallization and reveal an 'older' fault strand (~8 Ma) at 3066 m measured depth and a 'younger' fault strand (~4 Ma) at 3296 m measured depth. Today, the younger strand is the site of active creep behavior, demonstrating continued (re)activation of clay-weakened zones. Recent experimental work on aseismically creeping segments of SAFOD samples showed frictional strengths that are significantly weaker than neighboring wall rocks, offering independent validation of our model. Using a range of analytical methods that include X-ray diffraction, X-ray goniometry, elemental analysis and electron microscopy, we determined the location and nature of smectitic clay minerals in borehole samples, to assess the extent of smectitic phases in space and depth, any fault zone fabric development, and the swelling behavior of smectitic phases within the fault zone. Beyond the occurrence of illite-smectite in these relatively shallow fault rocks, the localized concentration of chlorite-smectite can extend the role of smectitic clays to depths down to ~10 km. We conclude that ultrathin hydrous clay films, or nanocoatings, on displacement surfaces play a key role in influencing weak fault and creep behavior along the San Andreas Fault at Parkfield, and likely in shallow

  8. Annual Check-up

    Science.gov (United States)

    ... Medical Conditions Nutrition & Fitness Emotional Health Annual Check-Up Posted under Health Guides . Updated 7 January 2015. + ... I get ready for my annual medical check-up? If this is your first visit to your ...

  9. First Direct Detection of Clay Minerals on Mars

    Science.gov (United States)

    Singer, R. B.; Owensby, P. D.; Clark, R. N.

    1985-01-01

    Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

  10. Compaction of microfossil and clay-rich chalk sediments

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    2001-01-01

    The aim of this study was to evaluate the role of microfossils and clay in the compaction of chalk facies sediments. To meet this aim, chalk sediments with varying micro texture were studied. The sediments have been tested uniaxially confined in a stainless-steel compaction cell. The sediments ar...

  11. Evaluation of peanut hulls as an alternative to bleaching clays

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, M. M.; El-Shami, S. M.; Taha, F. S.

    2011-07-01

    Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller's earth (FE) and PNH and O-passive (OP) and examined. The oxidative stability of oils was determined. Results for the investigated commercial bleaching clays revealed: TN > FE > F > TF > OP. Highest reduction in PV and PL, and highest bleachability were achieved for soybean oil bleached with 2% PNH carbonized at 500 degree centigrade for 30 min (PNH). Mixtures of PNH with the three chosen bleaching clays indicated that 1PNH : 2TN gave the highest bleachability. CSO was miscella bleached in hexane using PNH and resulted in an appreciable improvement in all oil characteristics, especially in bleachability. Oxidative stability of oils was in the following order: TN > control > FE > PNH with Induction period values of 23.1 > 6.43 > 5.73 > 2.85 h, respectively. (Author) 20 refs.

  12. Modeling of calcination of single kaolinitic clay particle

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse

    The present work aims at modeling of the calcination (dehydroxylation) process of clay particles, specifically kaolinite, and its thermal transformation. For such purpose, 1D single particle calcination model was developed based on the concept of shrinking core model to assess the dehydroxylation...

  13. Speciation of neptunium during sorption and diffusion in natural clay

    Science.gov (United States)

    Reich, T.; Amayri, S.; Bӧrner, P. J. B.; Drebert, J.; Frӧhlich, D. R.; Grolimund, D.; Kaplan, U.

    2016-05-01

    In argillaceous rocks, which are considered as a potential host rock for nuclear waste repositories, sorption and diffusion processes govern the migration behaviour of actinides like neptunium. For the safety analysis of such a repository, a molecular-level understanding of the transport and retardation phenomena of radioactive contaminants in the host rock is mandatory. The speciation of Np during sorption and diffusion in Opalinus Clay was studied at near neutral pH using a combination of spatially resolved synchrotron radiation techniques. During the sorption and diffusion experiments, the interaction of 8 μM Np(V) solutions with the clay lead to the formation of spots at the clay-water interface with increased Np concentrations as determined by μ-XRF. Several of these spots are correlated with areas of increased Fe concentration. Np L3-edge μ-XANES spectra revealed that up to 85% of the initial Np(V) was reduced to Np(IV). Pyrite could be identified by μ-XRD as a redox-active mineral phase responsible for the formation of Np(IV). The analysis of the diffusion profile within the clay matrix after an in-diffusion experiment for two months showed that Np(V) is progressively reduced with diffusion distance, i.e. Np(IV) amounted to ≈12% and ≈26% at 30 μm and 525 μm, respectively.

  14. Unfired clay bricks – retention curves and liquid diffusivities

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Peuhkuri, Ruut Hannele; Kristensen, A.; Hansen, E.J. de Place

    This paper presents retention curves and liquid diffusivities of two different types of unfired clay bricks, both produced in Denmark on commercial basis. The retention curves are determined by use of pressure plate and pressure membrane apparatuses. The liquid diffusivity is calculated on the...

  15. 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...

  16. Use of a clay modeling task to reduce chocolate craving.

    Science.gov (United States)

    Andrade, Jackie; Pears, Sally; May, Jon; Kavanagh, David J

    2012-06-01

    Elaborated Intrusion theory (EI theory; Kavanagh, Andrade, & May, 2005) posits two main cognitive components in craving: associative processes that lead to intrusive thoughts about the craved substance or activity, and elaborative processes supporting mental imagery of the substance or activity. We used a novel visuospatial task to test the hypothesis that visual imagery plays a key role in craving. Experiment 1 showed that spending 10 min constructing shapes from modeling clay (plasticine) reduced participants' craving for chocolate compared with spending 10 min 'letting your mind wander'. Increasing the load on verbal working memory using a mental arithmetic task (counting backwards by threes) did not reduce craving further. Experiment 2 compared effects on craving of a simpler verbal task (counting by ones) and clay modeling. Clay modeling reduced overall craving strength and strength of craving imagery, and reduced the frequency of thoughts about chocolate. The results are consistent with EI theory, showing that craving is reduced by loading the visuospatial sketchpad of working memory but not by loading the phonological loop. Clay modeling might be a useful self-help tool to help manage craving for chocolate, snacks and other foods. PMID:22369958

  17. 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...

  18. 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

  19. Performance of full scale enhanced reductive dechlorination in clay till

    DEFF Research Database (Denmark)

    Damgaard, Ida; Bjerg, Poul Løgstrup; Jacobsen, Carsten S.;

    2013-01-01

    At a low permeability clay till site contaminated with chlorinated ethenes (Gl. Kongevej, Denmark), enhanced reductive dechlorination (ERD) was applied by direct push injection of molasses and dechlorinating bacteria. The performance was investigated by long-term groundwater monitoring, and after 4...

  20. Cyclic viscoelasticity and viscoplasticity of polypropylene/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Hog Lejre, Anne-Lise

    2012-01-01

    Observations are reported in tensile relaxation tests under stretching and retraction on poly-propylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of hybrid nanocomposites. Adjustable parameters in...

  1. Iron/clay interaction in presence of bacteria

    International Nuclear Information System (INIS)

    A water percolation cell has been designed to assess the impact of bacteria on the interaction between clay and iron. It has been shown that at the interface between argillite and bulk iron, the presence of bacteria has led to local corrosion made of iron sulphide and pitting. (A.C.)

  2. Birds of a Feather... and Clay, Wire, Tissue and Paint!

    Science.gov (United States)

    Feiner, Lois

    2011-01-01

    What began as a review lesson in clay construction quickly became a fun learning experience filled with inspiring conversations and creatively painted birds. This lesson was successful from beginning to end, with a final reward when the artwork was displayed. The author describes the process of working on this project and shares how the students…

  3. Fire Resistance of Concrete Constructions with Expanded Clay Aggregate

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    The paper describes briefly a series of full-scale tests made as documentation for extending the field of application of the reduced cross section method from the structural codes to constructions based on expanded clay aggregate. As a special result the tests verify that slabs with a short...

  4. Pesticide leaching in macroporous clay soils: field experiment and modeling

    NARCIS (Netherlands)

    Scorza Júnior, R.P.

    2002-01-01

    Keywords : pesticide leaching, macropores, preferential flow, preferential transport, cracked clay soil, pesticide leaching models, groundwater contamination, inverse modeling, bentazone and imidacloprid. The presence of macropores (i.e. shrinkage c

  5. Study of delayed behaviour of clays in deep geologic formations

    International Nuclear Information System (INIS)

    This study is a cost-sharing contract with the European Atomic Energy Community within the framework of Research and Development Program on Management, Storage and Radioactive Waste Disposal. The aim of the work presented in this report is to study the time-dependent behaviour of deep clays in Laboratory or in situ, by means of tests of similar geometry, in order to get easy comparisons and to study scale effect. The cylindrical geometry has been chosen as it resembles in situ works (tunnels, galleries) more closely. The first part of the study concerns a new test on hollow-cylinder. The experimental system, set up specially for this study, has allowed to conduct experiments in which 3 loading parameters may be controlled independently. Different types of experiments can therefore be conducted to study various aspects of mechanical behavior of rocks. A comprehensive experimental program was conducted in the particular case of Boom clay. In the second part of the report devoted to in situ creep or relaxation dilatometer tests, by using new techniques or loading paths, it was shown that time-dependent convergence of boreholes can reach significant values, and is dependent on the direction of the borehole. The anisotropy of the initial state of stress was also put in evidence. The proposed constitutive model (part III) appears to be very suitable to explain the behavior of the Boom clay, in view of the experimental results. In particular, the scale effect is low for Boom clay. 15 refs., 58 figs., 10 tabs

  6. Field Performance Of Three Compacted Clay Landfill Covers

    Science.gov (United States)

    A study was conducted at sites in subtropical Georgia, seasonal and humid Iowa, and arid southeastern California to evaluate the field hydrology of compacted clay covers for final closure of landfills. Water balance of the covers was monitored with large (10 by 20 m ), instrumen...

  7. Suction effects in deep Boom clay block samples

    CERN Document Server

    Delage, Pierre; Tang, Anh-Minh; Cui, Yu-Jun; Li, Xiang-Ling

    2008-01-01

    Extensive investigations have been and are being carried out on a stiff clay from an underground research laboratory located at Mol (Belgium) called Boom clay, in the context of research into deep nuclear waste disposal. Suction effects in deep Boom clay block samples were investigated through the characterisation of the water retention and of the swelling properties of the clay. The data obtained allowed an estimation of the sample initial suction that was reasonably compatible with the in-situ state of stress at a depth of 223 m. The relationship between suction and stress changes during loading and unloading sequences were also examined by running oedometer tests with suction measurements. A rather wide range of the ratio s/sigma 'v (being s the suction and sigma 'v the effective vertical stress) was obtained (0.61 - 1), different from that proposed by Bishop et al; (1974). Finally, the effect of suction release under an isotropic stress close to the estimated sample suction was investigated. A slight swel...

  8. Fine particle clay catalysts for coal liquefaction. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Olson, E.S.

    1995-08-01

    In an effort to develop new disposable catalysts for direct coal liquefaction, several types of clay-supported pyrrhotite catalysts were prepared and tested. These included iron-pillared montmorillonite, mixed iron/alumina-pillared montmorillonite, iron-impregnated montmorillonite, and iron oxometallate-impregnated montmorillonite.

  9. Hand-Built Pottery: An Elementary Clay Project.

    Science.gov (United States)

    Farris, Cynthia Cox

    2001-01-01

    Describes an activity that takes two class periods where fifth-grade students created hand-built pots. Explains that each child receives a clay slab. Discusses how to make the major part of the pot from two pinch pots and how to create the neck and foot. (CMK)

  10. Barrier and Mechanical Properties of Starch-Clay Nanocomposite Films

    Science.gov (United States)

    The poor barrier and mechanical properties of biopolymer-based food packaging can potentially be enhanced by the use of layered silicates (nanoclay) to produce nanocomposites. In this study, starch-clay nano-composites were synthesized by a melt extrusion method. Natural (MMT) and organically modifi...

  11. Geochemical effects of electro-osmosis in clays

    KAUST Repository

    Loch, J. P. Gustav

    2010-02-13

    Geochemical effects of electro-osmosis in bentonite clay are studied in the laboratory, where a 6 mm thick bentonite layer is subjected to direct current. Acidification and alkalization near anode and cathode are expected, possibly causing mineral deterioration, ion mobilization and precipitation of new solids. Afterwards the clay is analysed by XRF and anolyte and catholyte are analysed by ICP-MS. In addition, as a preliminary experiment treated bentonite is analysed by high resolution μ-XRF. Electro-osmotic flow is observed. Due to its carbonate content the bentonite is pH-buffering. Alkalization in the catholyte is substantial. Ca, Na and Sr are significantly removed from the clay and accumulate in the catholyte. Recovery in the catholyte accounts for a small fraction of the element-loss from the clay. The rest will have precipitated in undetected solid phases. μ-XRF indicates the loss of Ca-content throughout the bentonite layer. © The Author(s) 2010.

  12. Clay Caterpillars: A Tool for Ecology & Evolution Laboratories

    Science.gov (United States)

    Barber, Nicholas A.

    2012-01-01

    I present a framework for ecology and evolution laboratory exercises using artificial caterpillars made from modeling clay. Students generate and test hypotheses about predation rates on caterpillars that differ in appearance or "behavior" to understand how natural selection by predators shapes distribution and physical characteristics of…

  13. Biodegradable nanocomposites from toughened polyhydroxybutyrate and titanate-modified montmorillonite clay

    Science.gov (United States)

    Montmorillonite clay treated with neopentyl (diallyl)oxy tri( dioctyl) pyrophosphato-titanate was used as a reinforcement for toughened bacterial bioplastic, Polyhydroxybutyrate (PHB) in order to develop novel biodegradable nanocomposites. The modified clay, PHB, toughening partner and specific comp...

  14. Characterization of sol-clay composites by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Silica-clay composites were prepared by reaction a 40 Angstrom silica sol with aqueous clay suspensions. The clays which were studied included Na+-montmorillonite, fluorohectorite, and the synthetic clay Laponite. The aggregation mechanism of the sol particles and the degree of dispersion of the clay layers were monitored by small-angle neutron scattering. The data for powdered silica-montmorillonite products showed the presence of highly dispersed clay platelets and spherical sol particles. The results suggest that the interaction between these two components inhibits the sol aggregation process. Studies on the products prepared from other types of clays, however, show that this interaction is highly dependent on the morphology and charge density of the clay platelets

  15. Major Clay Step features near Shorty's Island on the Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The major clay step features are defined as having a vertical face that is greater than 1.5 meters. The clay step features were qualitately identified using an...

  16. Minor Clay Step features near Shorty's Island on the Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The minor clay step features are defined as having a vertical face that is less than or equal to 1.5 meters. The clay step features were qualitately identified...

  17. Minor Clay Step features near Myrtle Bend on the Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The minor clay step features are defined as having a vertical face that is less than or equal to 1.5 meters. The clay step features were qualitately identified...

  18. Major Clay Step features near Myrtle Bend on the Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The major clay step features are defined as having a vertical face that is greater than 1.5 meters. The clay step features were qualitately identified using an...

  19. 76 FR 12786 - Culturally Significant Objects Imported for Exhibition Determinations: “Poetry in Clay: Korean...

    Science.gov (United States)

    2011-03-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Poetry in Clay: Korean Buncheong... objects to be included in the exhibition ``Poetry in Clay: Korean Buncheong Ceramics from the...

  20. Thermic and thermodynamic properties of desorption process of essential oil of Hyssopus seravshanicus from bentonite clays

    International Nuclear Information System (INIS)

    It shown, that desorption process of essential oil of Hyssopus seravshanicus from bentonite clays include by four parts (lines) and the nature between essential oil of Hyssopus seravshanicus from bentonite clays is physical and chemical sorption