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Sample records for clay block samples

  1. 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...

  2. 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)

  3. On grouting using a suspension of ultrafine clay on artificially cracked rock samples

    International Nuclear Information System (INIS)

    Recently there has been increasing social interest in the effective disposal of low-level radioactive wastes. The use of underground rock caverns is considered as a possible repository space. This paper presents a new grouting method which uses a suspension of liquefied ultrafine clay in fractured rock masses. In order to demonstrate the effect to block open cracks, two experiments were carried out on large-sized granite samples with open cracks. The experiments proved the method to be highly effective

  4. ASSESSMENT OF NATURAL RADIOACTIVITY IN CONCRETE BLOCK, EXTRUDED CLAY BRICK, AND MUD BRICK TAKEN FROM OGBOMOSO, SOUTHWESTERN, NIGERIA

    OpenAIRE

    Bolaji Omogbemiga AYINMODE; FAMAKINWA, Rebecca Oluwadamilola; Jonathan Olanipekun AJAYI

    2012-01-01

    This study evaluates the natural radioactivity in concrete block, extruded clay brick, and mud brick taken from Ogbomoso city. The six samples were collected from different part of the city, and were analyzed using highly sensitive HPGe gamma spectrometer. The mean activity concentration in Bq Kg -1 of 40K , 238 U (226Ra) and 232Th were 135.10 ± 3.23, 9.58 ± 3.16 and 14.30 ± 3.32 respectively in concrete block ; 66.34 ± 6.66, 6.81 ± 2.26 and 6.78 ± 2....

  5. Evaluation of correlation between physical properties and ultrasonic pulse velocity of fired clay samples.

    Science.gov (United States)

    Özkan, İlker; Yayla, Zeliha

    2016-03-01

    The aim of this study is to establish a correlation between physical properties and ultrasonic pulse velocity of clay samples fired at elevated temperatures. Brick-making clay and pottery clay were studied for this purpose. The physical properties of clay samples were assessed after firing pressed clay samples separately at temperatures of 850, 900, 950, 1000, 1050 and 1100 °C. A commercial ultrasonic testing instrument (Proceq Pundit Lab) was used to evaluate the ultrasonic pulse velocity measurements for each fired clay sample as a function of temperature. It was observed that there became a relationship between physical properties and ultrasonic pulse velocities of the samples. The results showed that in consequence of increasing densification of the samples, the differences between the ultrasonic pulse velocities were higher with increasing temperature. These findings may facilitate the use of ultrasonic pulse velocity for the estimation of physical properties of fired clay samples. PMID:26725032

  6. 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

  7. Effect of Nano-clay on Rheological and Extrusion Foaming Process of a Block-Copolymerized Polypropylene

    Directory of Open Access Journals (Sweden)

    Wang Mingyi

    2016-01-01

    Full Text Available The effects of nano-clay and the corresponding coupling agent maleic anhydride grafted polypropylene (PP-g-MAH on thermal properties, rheological properties and extrusion foaming process of a block-copolymerized polypropylene (B-PP were studied. Supercritical CO2 (SC CO2 was used as the foaming agent with a concentration of 5wt%. Each step of foamed B-PP/ PP-g-MAH/ nano-clay composites processing is addressed, including mixing of the composites, manufacture of the composites, foaming process of the composites and characterization of the cell structure. The results showed that incorporation of nano-clay and PP-g-MAH caused reduced melt strength and complex viscosity of B-PP. However, the heterogeneous nucleation induced by nano-clay and PP-g-MAH improved the maximum foaming expansion ratio and cell-population density of B-PP foam.

  8. XRF determination of major elemental contents of clay samples from north-west peninsular Malaysia

    International Nuclear Information System (INIS)

    Being an imperative material for man either used as building materials, pottery or as components in material industry and technology, knowledge of clays elemental contents is important. In the present study ten clay samples obtained from various locations in North-West Peninsular Malaysia were used. Majority of the clays were economically manufactured to be used as building materials or pottery. The objective of study was to determine the main elemental contents of the samples, and relate the results to the types of minerals, as well as to compare them with clays from other studies. In the study X-ray Fluorescence (XRF) coupled to samples dilution method and standard calibration samples was used. The elements detected in the study were Si, Al, Fe, Ti, K, and Ca. Depending on locations, the percentage concentration ranged between 24.8 - 32.4 for Si, 10.8 - 19.0 for Al, 0.09 - 2.12 for Fe, 0.08 - 1.13 for Ti, 0.45 - 3.39 for K and trace amount of Ca and P. However, Mg that normally found in typical clay was not found in the studied samples. Comparing the oxide of the major elements with other studies, it was found that the clay samples contained mixtures of kaolinite (two-layered structure) and illite (three-layered structure). (author)

  9. Shear Strength of Remoulding Clay Samples Using Different Methods of Moulding

    Science.gov (United States)

    Norhaliza, W.; Ismail, B.; Azhar, A. T. S.; Nurul, N. J.

    2016-07-01

    Shear strength for clay soil was required to determine the soil stability. Clay was known as a soil with complex natural formations and very difficult to obtain undisturbed samples at the site. The aim of this paper was to determine the unconfined shear strength of remoulded clay on different methods in moulding samples which were proctor compaction, hand operated soil compacter and miniature mould methods. All the samples were remoulded with the same optimum moisture content (OMC) and density that were 18% and 1880 kg/m3 respectively. The unconfined shear strength results of remoulding clay soils for proctor compaction method was 289.56kPa with the strain 4.8%, hand operated method was 261.66kPa with the strain 4.4% and miniature mould method was 247.52kPa with the strain 3.9%. Based on the proctor compaction method, the reduction percentage of unconfined shear strength of remoulded clay soil of hand operated method was 9.66%, and for miniature mould method was 14.52%. Thus, because there was no significant difference of reduction percentage of unconfined shear strength between three different methods, so it can be concluded that remoulding clay by hand operated method and miniature mould method were accepted and suggested to perform remoulding clay samples by other future researcher. However for comparison, the hand operated method was more suitable to form remoulded clay sample in term of easiness, saving time and less energy for unconfined shear strength determination purposes.

  10. A method for disaggregating clay concretions and eliminating formalin smell in the processing of sediment samples

    DEFF Research Database (Denmark)

    Cedhagen, Tomas

    1989-01-01

    A complete handling procedure for processing sediment samples is described. It includes some improvements of conventional methods. The fixed sediment sample is mixed with a solution of the alkaline detergent AJAX® (Colgate-Palmolive). It is kept at 80-900 C for 20-40 min. This treatment facilitat...... subsequent sorting as it disaggregates clay concretions and faecal pellets ·but leaves even fragile organisms clean and unaffected. The ammonia in the detergent eliminates the formalin smell....

  11. Thermal models and clay diagenesis in the Tertiary-Cretaceous sediments of the Alava block (Basque-Cantabrian basin, Spain)

    OpenAIRE

    Aróstegui, J.; Sangüesa, F. J.; Nieto, F.; Uriarte, J. A.

    2006-01-01

    Diagenesis in the Cretaceous and Tertiary sediments of the Alava Block (Basque-Cantabrian basin) has been studied using the clay mineralogy (X-ray diffraction) of cuttings from three representative wells of a N–S cross-section. More than 5500 m of various lithologies (marls, mudstones and sandstones) have been drilled in the northern part of the domain, and 2100 m in the southern zone. The illitization of smectite and the disappearance of kaolinite, due to diagenesis, are the most characteris...

  12. A FEM comparative analysis of the thermal efficiency among floors made up of clay, concrete and lightweight concrete hollow blocks

    International Nuclear Information System (INIS)

    This paper presents a comparative non-linear thermal analysis for a total of eighteen different in situ cast floors varying both the constituent materials of the hollow blocks (clay, concrete and lightweight concrete) and the shape and number of recesses (six different block types) using the finite element method (FEM). Based on the non-linear thermal analysis of the different configurations by FEM and considering both upward and downward heat flows, it is possible to choose the best candidate floor from the thermal point of view. Mathematically, the non-linearity is due to the radiation boundary condition inside the recesses of the blocks. The comparative analysis of the floors is carried out from the finite element analysis through the two important parameters: the average mass overall thermal efficiency and the equivalent thermal conductivity. Finally, the results and conclusions reached in this work are exposed. - Research highlights: → The nonlinear thermal complex analysis of different floors. → The selection procedure of the best candidate block. → The influence of the different recesses in the block's thermal performance. →The thermal efficiency of different constituent materials.

  13. Fast Sampling-Based Whole-Genome Haplotype Block Recognition.

    Science.gov (United States)

    Taliun, Daniel; Gamper, Johann; Leser, Ulf; Pattaro, Cristian

    2016-01-01

    Scaling linkage disequilibrium (LD) based haplotype block recognition to the entire human genome has always been a challenge. The best-known algorithm has quadratic runtime complexity and, even when sophisticated search space pruning is applied, still requires several days of computations. Here, we propose a novel sampling-based algorithm, called S-MIG (++), where the main idea is to estimate the area that most likely contains all haplotype blocks by sampling a very small number of SNP pairs. A subsequent refinement step computes the exact blocks by considering only the SNP pairs within the estimated area. This approach significantly reduces the number of computed LD statistics, making the recognition of haplotype blocks very fast. We theoretically and empirically prove that the area containing all haplotype blocks can be estimated with a very high degree of certainty. Through experiments on the 243,080 SNPs on chromosome 20 from the 1,000 Genomes Project, we compared our previous algorithm MIG (++) with the new S-MIG (++) and observed a runtime reduction from 2.8 weeks to 34.8 hours. In a parallelized version of the S-MIG (++) algorithm using 32 parallel processes, the runtime was further reduced to 5.1 hours. PMID:27045830

  14. Comparison of the thermal properties of clay samples as potential walling material for naturally cooled building design

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The thermal properties of different clay samples obtainedfrom locations in Akwa Ibom State, Nigeria were investigated andcomppared, and in order to establish their suitability as buildingmaterial from energy conservation point of view. The results showedthat sstoneware clay has the highest solar radiation absorptivityof 22.32 m-1 while kaolin clay has the lowest radiation absoptivityof 14.46 m-1. A model for the prediction of temperature variationwith thickness of the samples was developed. Results showed thatkaolin would make the best choice for the design of a naturallycooled building.

  15. Study of matrix micro-cracking in nano clay and acrylic tri-block-copolymer modified epoxy/basalt fiber-reinforced pressure-retaining structures

    Directory of Open Access Journals (Sweden)

    2011-10-01

    Full Text Available In fiber-reinforced polymer pressure-retaining structures, such as pipes and vessels, micro-level failure commonly causes fluid permeation due to matrix cracking. This study explores the effect of nano-reinforcements on matrix cracking in filament-wound basalt fiber/epoxy composite structures. The microstructure and mechanical properties of bulk epoxy nanocomposites and hybrid fiber-reinforced composite pipes modified with acrylic tri-block-copolymer and organophilic layered silicate clay were investigated. In cured epoxy, the tri-block-copolymer phase separated into disordered spherical micelle inclusions; an exfoliated and intercalated structure was observed for the nano-clay. Block-copolymer addition significantly enhanced epoxy fracture toughness by a mechanism of particle cavitation and matrix shear yielding, whereas toughness remained unchanged in nano-clay filled nanocomposites due to the occurrence of lower energy resistance phenomena such as crack deflection and branching.Tensile stiffness increased with nano-clay content, while it decreased slightly for block-copolymer modified epoxy. Composite pipes modified with either the organic and inorganic nanoparticles exhibited moderate improvements in leakage failure strain (i.e. matrix cracking strain; however, reductions in functional and structural failure strength were observed.

  16. Grafting of poly[(methyl methacrylate)-block-styrene] onto cellulose via nitroxide-mediated polymerization, and its polymer/clay nanocomposite.

    Science.gov (United States)

    Karaj-Abad, Saber Ghasemi; Abbasian, Mojtaba; Jaymand, Mehdi

    2016-11-01

    For the first time, nitroxide-mediated polymerization (NMP) was used for synthesis of graft and block copolymers using cellulose (Cell) as a backbone, and polystyrene (PSt) and poly(methyl metacrylate) (PMMA) as the branches. For this purpose, Cell was acetylated by 2-bromoisobutyryl bromide (BrBiB), and then the bromine group was converted to 4-oxy-2,2,6,6-tetramethylpiperidin-1-oxyl group by a substitution nucleophilic reaction to afford a macroinitiator (Cell-TEMPOL). The macroinitiator obtained was subsequently used in controlled graft and block copolymerizations of St and MMA monomers to yield Cell-g-PSt and Cell-g-(PMMA-b-PSt). The chemical structures of all samples as representatives were characterized by FTIR and (1)H NMR spectroscopies. In addition, Cell-g-(PMMA-b-PSt)/organophilic montmorillonite nanocomposite was prepared through a solution intercalation method. TEM was used to evaluate the morphological behavior of the polymer-clay system. It was demonstrated that the addition of small percent of organophilic montmorillonite (O-MMT; 3wt.%) was enough to improve the thermal stability of the nanocomposite. PMID:27516276

  17. Geochemical study of evaporite and clay mineral-oxyhydroxide samples from the Waste Isolation Pilot Plant site

    International Nuclear Information System (INIS)

    Samples of clay minerals, insoluble oxyhydroxides, and their host evaporites from the WIPP site have been studied for their major and minor elements abundances, x-ray diffraction characteristics, K-Ar ages, and Rb-Sr ages. This study was undertaken to determine their overall geochemical characteristics and to investigate possible interactions between evaporates and insoluble constituents. The evaporite host material is water-soluble, having Cl/Br ratios typical of marine evaporites, although the Br content is low. Insoluble material (usually a mixture of clay minerals and oxyhydroxide phases) yields very high Cl/Br ratios, possibly because of Cl from admixed halide minerals. This same material yields K/Rb and Th/U ratios in the normal range for shales; suggesting little, if any, effect of evaporite-induced remobilization of U, K, or Rb in the insoluble material. The rare-earth element (REE) data also show normal REE/chondrite (REE/CHON) distribution patterns, supporting the K/Rb and Th/U data. Clay minerals yield K-Ar dates in the range 365 to 390 Ma and a Rb-Sr isochron age of 428 ± 7 Ma. These ages are well in excess of the 220- to 230-Ma formational age of the evaporites, and confirm the detrital origin of the clays. The ages also show that any evaporite or clay mineral reactions that might have occurred at or near the time of sedimentation and diagenesis were not sufficient to reset the K-Ar and Rb-Sr systematics of the clay minerals. Further, x-ray data indicate a normal evaporitic assemblage of clay minerals and Fe-rich oxyhydroxide phases. The clay minerals and other insoluble material appear to be resistant to the destructive effects of their entrapment in the evaporites, which suggests that these insoluble materials would be good getters for any radionuclides (hypothetically) released from the storage of radioactive wastes in the area

  18. The Effects of Groundnut Shell Addition on The Insulating Properties of Clay Samples From Kogi State Nigeria

    Directory of Open Access Journals (Sweden)

    Manukaji John U

    2013-01-01

    Full Text Available Clay samples from three towns in Kogi state were examined with the aim of determining their chemical composition as well as testing for their suitability as refractory insulating materials for local furnaces. Refractories are required for many other industries in Nigeria like in chemical, ceramic, petrochemical, oil,foundry and iron and steel industries. The presence of air in these pores reduces the conductive capacity of the refractories and therefore increasing their insulating characteristics. Apart from the natural occurring fire clays which has been adjudged an insulating refractories, other clays can have their insulating characteristics improved by the addition of materials like saw dust, rice husks and other farm wastes. Experiments were carried out to determine how the addition of groundnut shell could improve the refractory properties of clay samples from Kogi State. The experiments were carried out on the four mechanical properties that enhance the insulating properties of clay which are linear shrinkage, thermal conductivity, apparent porosity and solid density .The results showed significant improvement in these properties

  19. Colloid and Phosphorus Leaching From Undisturbed Soil Cores Sampled Along a Natural Clay Gradient

    DEFF Research Database (Denmark)

    Vendelboe, Anders Lindblad; Møldrup, Per; Heckrath, Goswin Johann;

    2011-01-01

    followed by lower and stable colloid and phosphorus concentrations. The mass of particles leached at first flush was independent of clay content and was attributed to the instant release of particles associated with the macropore walls and released upon contact with flowing water. Below a clay content of È......0.15 kg kgj1, the later leaching (after the first flush) of particles was independent of the clay content. Above this threshold, there was a positive relationship between the mass of leached particles after the first flush and the clay content. Particle release after the first flush was linearly...... correlated to the accumulated outflow and was described as a diffusion controlled process, using ¾(accumulated outflow). The mass of leached particles was positively correlated to the clay content as well as to water-dispersible colloids. Particulate phosphorus (P) was linearly correlated to concentration of...

  20. Development of the methodology of sample preparation to X-ray diffractometry of clay minerals at Petrobras Research Center

    International Nuclear Information System (INIS)

    Various procedures can be used in the analysis of the clay mineral content of rocks by X-ray diffraction. This article describes the principal ones and discusses those adopted in the X-ray clay mineral laboratory of the PETROBRAS Research Center (CENPES) in Rio de Janeiro. This article presents the methodology used and provides users with information about its application and limitations. The methodology has been developed to study polymineral samples. The aim to identify clay mineral groups and to estimate their relative proportions. Of the four main steps of this analysis - separation and concentration of clay minerals, preparation of oriented specimens, X-ray irradiation under standard conditions and interpretation of X-ray diffraction patterns - only the first three are discussed here. Clay minerals occur mainly in the < 2 μ fraction. They are separated from the other minerals by disaggregation followed by size fractionation. The rocks are immersed in distilled water and disaggregated with an ultrasonic microprobe. The < 2 μ fraction is then separated by centrifugation. (author)

  1. Block Slides on Extremely Weak Tectonic Clay Seams in Openly Folded Tertiary Mud-Rocks at Auckland and the Rangitikei Valley, North Island, New Zealand

    Science.gov (United States)

    Prebble, Warwick M.; Williams, Ann L.

    2016-06-01

    Block slides have developed on extremely weak, thin clay seams of tectonic origin, parallel to bedding in gently dipping sandstones and mudstones of Tertiary age. Two areas of noted instability are investigated at Auckland and the Rangitikei valley. Dimensions range from 100 m across × 100 m long for short displacement block slides up to 4 km across × 3 km long for large landslide complexes in which block slides are a major component. Displacements of blocks range from incipient (cm) through short (30 m) to 2 or 3 km for large slides. Many of the Auckland slides are dormant but likely to move in a 2000 year return period earthquake or 100 year high intensity rain storm. At Rangitikei there are many active, younger slides. Sliding rates for active failures vary from a few cm/year to 50 m in 30 min. Host rocks are weak to very weak clayey sandstones and sandy mudstones. The seams are rich in smectite. They have polished and crushed walls, may have slickensides and some contain rounded rock fragments. Laboratory shear strength of the seams is 13 kPa cohesion and 13° friction, with a lower bound of 8° at zero cohesion. Strength is increased at the field scale by waviness, steps and splays. Continuity can be demonstrated over distances of hundreds of metres. Key investigation methods were mapping, shafts and trenches. Tectonic uplift, folding and faulting of the weak Tertiary strata and river down-cutting are perpetuating block slide development.

  2. Calculation of the effective diffusion coefficient during the drying of clay samples

    OpenAIRE

    Vasić Miloš; Radojević Zagorka; Grbavčić Željko

    2012-01-01

    The aim of this study was to calculate the effective diffusion coefficient based on experimentally recorded drying curves for two masonry clays obtained from different localities. The calculation method and two computer programs based on the mathematical calculation of the second Fick’s law and Cranck diffusion equation were developed. Masonry product shrinkage during drying was taken into consideration for the first time and the appropriate correction was entered into the calculation. ...

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

    International Nuclear Information System (INIS)

    processes that may develop locally in Opalinus Clay upon disturbance by drilling and excavation (i.e., introduction of space, water, microbes and nutrients). In a second part of this work, results are presented here from detection and identification of microorganisms in water which accumulated in an open borehole drilled in the Opalinus Clay (BEZ-G5). Besides introduced (exogenous) microorganisms, such water may contain autochthonous species. The latter may be easier to detect in water samples than by direct analysis of the clay rock. Both culturing (aerobic and anaerobic media) and direct (DNA extraction and PCR-DGGE) methods were used. Pure cultures of bacteria isolated in several enrichment media and identified by DNA extraction, PCR and sequencing indicated that most isolated bacteria are heterotrophic aerobes or facultative anaerobes commonly isolated from soil and water (such as Dietzia sp., Pseudomonas sp.) and therefore probably contaminants. In parallel, direct DNA extraction from water and PCR-DGGE revealed other contaminant bacteria (such as Staphylococcus sp., Rhizobium sp.). Nevertheless, some species may be indigenous in the Opalinus Clay such as Desulfosporosinus sp. isolated on sulfate-reducing media or Speleomyces sp., identified by PCRDGGE and previously isolated from a medieval mine. Complementary characterizations of these bacteria are required to confirm these first results. The diversity of microorganisms detected shows that both culturing and molecular approaches are essential to study this type of environment. (authors)

  4. Estimation model of Cs-137 activity in soil samples derives from percentage of organic carbon and silt-clay

    International Nuclear Information System (INIS)

    Estimation of Cs-137 activity in soil samples was conducted at Nganjuk area through its soil organic carbon and silt-clay percentage. Twenty-six soil samples taken from Nganjuk area have been used to establish the relationship of Cs-137 activity and its soil samples quality parameters by using SPSS (Statistical Product and Service Solutions) software. Chemical parameters of samples have higher variation compared to the physical. Estimated of Cs-137 activity in soil samples can be established by two parameters, those are percent of total organic carbon and percent of silt-clay contents. However, these two parameters could only explained 69.3 % of Cs-137 activity, the remaining 30.7 % potentially could be due to 10 % of error measurement, run-on redistribution of soil, farming as well as tillage system. By using the soil quality parameters, the Cs-137 activity under the limit detection could be estimated, hence, its usefulness to estimate the erosion rate through applying the Cs-model. (author)

  5. Petrographic report on clay-rich samples from Permian Unit 4 salt, G. Friemel No. 1 well, Palo Duro Basin, Deaf Smith County, Texas: unanalyzed data

    International Nuclear Information System (INIS)

    This report presents the results of mineralogic and petrographic analyses performed on five samples of clay-rich rock from salt-bearing Permian strata sampled by drill core from G. Friemel No. 1 Well, Deaf Smith County, Texas. Five samples of clay-rich rock from depths of about 2457, 2458, 2521, 2548, and 2568 feet were analyzed to determine the amounts of soluble phase (halite) and the amounts and mineralogy of the insoluble phases. The amounts of halite found were 59, 79, 47, 40, and 4 weight percent, respectively, for the samples. The insoluble minerals are predominately clay (20 to 60 volume percent) and anhydrite (up to 17 volume percent), with minor (about 1.0%) and trace amounts of quartz, dolomite, muscovite, and gypsum. The clays include illite, chlorite, and interstratified chlorite-smectite. The results presented in this petrographic report are descriptive, uninterpreted data. 2 references, 7 tables

  6. Petrographic report on clay-rich samples from Permian Unit 4 salt, G. Friemel No. 1 well, Palo Duro Basin, Deaf Smith County, Texas: unanalyzed data

    Energy Technology Data Exchange (ETDEWEB)

    Fukui, L M

    1983-09-01

    This report presents the results of mineralogic and petrographic analyses performed on five samples of clay-rich rock from salt-bearing Permian strata sampled by drill core from G. Friemel No. 1 Well, Deaf Smith County, Texas. Five samples of clay-rich rock from depths of about 2457, 2458, 2521, 2548, and 2568 feet were analyzed to determine the amounts of soluble phase (halite) and the amounts and mineralogy of the insoluble phases. The amounts of halite found were 59, 79, 47, 40, and 4 weight percent, respectively, for the samples. The insoluble minerals are predominately clay (20 to 60 volume percent) and anhydrite (up to 17 volume percent), with minor (about 1.0%) and trace amounts of quartz, dolomite, muscovite, and gypsum. The clays include illite, chlorite, and interstratified chlorite-smectite. The results presented in this petrographic report are descriptive, uninterpreted data. 2 references, 7 tables.

  7. Three-dimensional FDEM numerical simulation of failure processes observed in Opalinus Clay laboratory samples

    Institute of Scientific and Technical Information of China (English)

    Omid Mahabadi; Patrick Kaifosh; Paul Marschall; Tim Vietor

    2014-01-01

    This study presents the first step of a research project that aims at using a three-dimensional (3D) hybrid finite-discrete element method (FDEM) to investigate the development of an excavation damaged zone (EDZ) around tunnels in a clay shale formation known as Opalinus Clay. The 3D FDEM was first calibrated against standard laboratory experiments, including Brazilian disc test and uniaxial compression test. The effect of increasing confining pressure on the mechanical response and fracture propagation of the rock was quantified under triaxial compression tests. Polyaxial (or true triaxial) simulations highlighted the effect of the intermediate principal stress (s2) on fracture directions in the model: as the intermediate principal stress increased, fractures tended to align in the direction parallel to the plane defined by the major and intermediate principal stresses. The peak strength was also shown to vary with changing s2. ? 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. All rights reserved.

  8. Analysis of the seismic signals generated by controlled single-block rockfalls on soft clay shales sediments: the Rioux Bourdoux slope experiment (French Alps).

    Science.gov (United States)

    Hibert, Clément; Provost, Floriane; Malet, Jean-Philippe; Bourrier, Franck; Berger, Frédéric; Bornemann, Pierrick; Borgniet, Laurent; Tardif, Pascal; Mermin, Eric

    2016-04-01

    Understanding the dynamics of rockfalls is critical to mitigate the associated hazards but is made very difficult by the nature of these natural disasters that makes them hard to observe directly. Recent advances in seismology allow to determine the dynamics of the largest landslides on Earth from the very low-frequency seismic waves they generate. However, the vast majority of rockfalls that occur worldwide are too small to generate such low-frequency seismic waves and thus these methods cannot be used to reconstruct their dynamics. However, if seismic sensors are close enough, these events will generate high-frequency seismic signals. Unfortunately we cannot yet use these high-frequency seismic records to infer parameters synthetizing the rockfall dynamics as the source of these waves is not well understood. One of the first steps towards understanding the physical processes involved in the generation of high-frequency seismic waves by rockfalls is to study the link between the dynamics of a single block propagating along a well-known path and the features of the seismic signal generated. We conducted controlled releases of single blocks of limestones in a gully of clay-shales (e.g. black marls) in the Rioux Bourdoux torrent (French Alps). 28 blocks, with masses ranging from 76 kg to 472 kg, were released. A monitoring network combining high-velocity cameras, a broadband seismometer and an array of 4 high-frequency seismometers was deployed near the release area and along the travel path. The high-velocity cameras allow to reconstruct the 3D trajectories of the blocks, to estimate their velocities and the position of the different impacts with the slope surface. These data are compared to the seismic signals recorded. As the distance between the block and the seismic sensors at the time of each impact is known, we can determine the associated seismic signal amplitude corrected from propagation and attenuation effects. We can further compare the velocity, the

  9. Sample size calculation for microarray experiments with blocked one-way design

    Directory of Open Access Journals (Sweden)

    Jung Sin-Ho

    2009-05-01

    Full Text Available Abstract Background One of the main objectives of microarray analysis is to identify differentially expressed genes for different types of cells or treatments. Many statistical methods have been proposed to assess the treatment effects in microarray experiments. Results In this paper, we consider discovery of the genes that are differentially expressed among K (> 2 treatments when each set of K arrays consists of a block. In this case, the array data among K treatments tend to be correlated because of block effect. We propose to use the blocked one-way ANOVA F-statistic to test if each gene is differentially expressed among K treatments. The marginal p-values are calculated using a permutation method accounting for the block effect, adjusting for the multiplicity of the testing procedure by controlling the false discovery rate (FDR. We propose a sample size calculation method for microarray experiments with a blocked one-way design. With FDR level and effect sizes of genes specified, our formula provides a sample size for a given number of true discoveries. Conclusion The calculated sample size is shown via simulations to provide an accurate number of true discoveries while controlling the FDR at the desired level.

  10. Diffusion of HTO, 36Cl-, 125I- and 22Na+ in Opalinus Clay: Effect of Confining Pressure, Sample Orientation, Sample Depth and Temperature

    International Nuclear Information System (INIS)

    Effective diffusion coefficients (De), rock capacity factors (α) and diffusion-accessible porosities (ε) were measured using the through-diffusion technique. Transport (diffusion) was measured both perpendicular and parallel to the bedding. Special cells that allowed the application of an axial confining pressure were designed. The pressures applied ranged from 1 to 5 MPa for Mont Terri samples and between 4 and 15 MPa for Benken samples, the upper values representing the in-situ confining pressure at both locations. The test solutions used in the experiments were synthetic Opalinus Clay pore water, which has Na and Cl as main components (Mont Terri: I = 0.39 M; Benken: I = 0.20 M). Pressure only had a small effect on the value of the effective diffusion coefficients. In the case of Mont Terri samples, increasing the pressure from 1 to 5 MPa resulted in a decrease of the effective diffusion coefficient of 20% for HTO, 27% for 36Cl-, 29% for 125I- and 17 % for 22Na+. In the case of Benken samples, increasing the pressure from 4 to 15 MPa resulted in a decrease of De of 17% for HTO, 22% for 36Cl-, 32% for 125I- and 17 % for 22Na+. Moreover, the effective diffusion coefficients for for 36Cl-are smaller than for HTO, which is consistent with an effect arising from anion exclusion. This ion exclusion effect is smaller in samples from Mont Terri than in samples from Benken, which can be explained by the higher ionic strength of the Mont Terri water used in the experiments. The diffusion of 22Na+ is similar to that of HTO in the case of Mont Terri OPA. For Benken OPA, the De value of 22Na+ is a factor of 2 higher than that of HTO. This last observation cannot be explained so far but is comparable to experimental data from ANDRA (1999) on Callovo-Oxfordian claystones from the Meuse/Haute Same site. 125I- is retarded with respect to 36Cl-. This is caused by a weak sorption of 125I- on the Opalinus Clay. The distribution coefficients, calculated from the rock capacity

  11. A Scalable Blocked Gibbs Sampling Algorithm For Gaussian And Poisson Regression Models

    OpenAIRE

    Johnson, Nicholas A.; Kuehnel, Frank O.; Amini, Ali Nasiri

    2016-01-01

    Markov Chain Monte Carlo (MCMC) methods are a popular technique in Bayesian statistical modeling. They have long been used to obtain samples from posterior distributions, but recent research has focused on the scalability of these techniques for large problems. We do not develop new sampling methods but instead describe a blocked Gibbs sampler which is sufficiently scalable to accomodate many interesting problems. The sampler we describe applies to a restricted subset of the Generalized Linea...

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

    International Nuclear Information System (INIS)

    Water vapour sorption isotherms at 299K for the Na+-exchanged clay-sized (≤ 2μm e.s.d.) fraction of two sets of samples taken at three different depths from a tropical soil profile have been studied. One set of samples was treated (with H2O2) for the removal of much of the organic matter (OM); the other set (of the same samples) was not so treated. The isotherms obtained were all of type II and analyses by the BET method yielded values for the Specific Surface Areas (SSA) and for the average energy of adsorption of the first layer of adsorbate (Ea). OM content and SSA for the untreated samples were found to decrease with depth. Whereas removal of organic matter made negligible difference to the SSA of the top/surface soil, the same treatment produced a significant increase in the SSA of the samples taken from the middle and from the lower depths in the profile; the resulting increase was more pronounced for the subsoil. It has been deduced from these results that OM in the surface soil was less involved with the inorganic soil colloids than that in the subsoil. The increase in surface area which resulted from the removal of OM from the subsoil was most probably due to disaggregation. Values of Ea obtained show that for all the samples the adsorption of water vapour became more energetic after the oxidative removal of organic matter; the resulting ΔEa also increased with depth. This suggests that in the dry state, the ''cleaned'' surface of the inorganic soil colloids was more energetic than the ''organic-matter-coater surface''. These data provide strong support for the deduction that OM in the subsoil was in a more ''combined'' state than that in the surface soil. (author). 21 refs, 4 figs, 2 tabs

  13. Sampling and Analysis Instruction for the Demolition of the Masonry Block for the 108-F Biological Laboratory

    International Nuclear Information System (INIS)

    This sampling and analysis instruction (SAI) has been prepared to clearly define the sampling and analysis activities to be performed in support of the demolition and disposition (or disposal) of the 108-F Biological Laboratory masonry block walls

  14. Air oxidation of samples from different clay formations of East Paris basin: quantitative and qualitative consequences on the dissolved organic matter

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. During the excavation and the building of an underground research laboratory in clay geological formations, exposure to air is one of the most important parameters affecting the composition of fossil organic matter. Indeed the net effect of air oxidation of the organic matter is enrichment in oxygen and carbon combined with a loss of hydrogen. Effluents formed are CO2 and water as well as the liberation of hydrocarbons. This process may have an impact on water chemistry of the clay, especially on the quantity and composition of Dissolved Organic Matter (DOM). The clays studied were the following and may be distinguished on the basis of their organic matter content: - The Callovo-Oxfordian argillite, collected in the Bure Underground Research Laboratory (Meuse, France), which contains a mixture of type II and III kerogen; - The Toarcian shales of East Paris Basin collected from drilling EST 204 (Meuse, France) contains type II kerogen; - The Kimmeridgian shales of East Paris Basin collected from drilling HTM 102 (Meuse, France) also contains type II kerogen. The powdered clay samples were oxidized in a ventilated oven at 100 C under air flow during 2, 256, 512 and 1088 hours for Callovo-Oxfordian samples and during 512 and 2048 hours for Toarcian and Kimmeridgian samples. The DOM of each sample was extracted by soxhlet using pure water. Different analyses were carried out: - Quantitative evolution of DOM with the oxidation process; - Evolution of several chemical parameters of DOM with oxidation using molecular analyses (PyGC-MS) molecular weight distribution (GPC-HPLC) as well as spectroscopic measurements (3D-Fluorescence). Increasing oxidation induces an increase of DOC values for all samples. Also, Changes in the chemical composition of the DOM are observed: decrease in the molecular weight range; enrichment in acidic functional groups (alkane-dioic acids, alkanoic acids, aromatics poly acids). Moreover the

  15. 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.

  16. 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...

  17. 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.

  18. 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

  19. 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 ...

  20. Effect of block net use and time of sampling on backpack electrofishing catches in three Kansas reservoirs

    Science.gov (United States)

    Schoenebeck, C.W.; Strakosh, T.R.; Guy, C.S.

    2005-01-01

    Using backpack electrofishing in three Kansas reservoirs, we investigated the need for block nets when estimating density (fish/ha) and species diversity and determined whether time of sampling affected catch rates (fish/h) of age-0 largemouth bass Micropterus salmoides and age-0 Lepomis spp. and species diversity. Block nets were used to enclose or buoys were used to mark the boundaries of 149 m2 of reservoir surface area. Species richness, diversity, and density of age-0 largemouth bass and Lepomis spp. did not differ significantly between areas enclosed with block nets and areas marked with buoys, but species richness, diversity, and catch rates differed significantly between day and night sampling. Age-0 largemouth bass and Lepomis spp. catch rates, species richness, and species diversity were all significantly higher during night sampling. Our results indicate that use of block nets may not be necessary to estimate age-0 largemouth bass and Lepomis spp. densities, species richness, or diversity in reservoir littoral areas. We recommend night sampling because of significantly higher catch rates and better representation of the littoral fish assemblage. ?? Copyright by the American Fisheries Society 2005.

  1. Using block counts and distance sampling to estimate populations of chamois

    Directory of Open Access Journals (Sweden)

    Herrero, J.

    2011-12-01

    Full Text Available This study compared the efficacies of total block counts (BC and distance sampling (DS procedures to estimate the abundance of chamois populations in two mountain massifs, Posets and Maladeta, Spain. In 2002, 2006, 2007, and 2008, chamois populations were surveyed along itineraries above the timberline, twice per year: in July, after the parturition period, and in November, during the rut. The latter survey was used to estimate the sex ratio and to correct the proportion of males present in July. In 2008, poor weather prevented surveys in November. In the DS procedure, we used the data collected using BC and calculated the distances of the mapped groups to the itinerary, using a Geographical Information System. In Posets, estimates of population densities derived using BC ranged from 5.5 to 9.1 chamois km-2, while those derived using DS ranged from 7.5 to 9.7 chamois km-2. In Maladeta, the estimates ranged from 3.4 to 5.4 chamois km-2 (BC and from 4.6 to 8.5 chamois km-2 (DS. Coefficients of variation of DS ranged between 14% and 26%. In five of eight cases the counts of population size derived from BC were within the 95% confidence interval of the estimate derived from DS. In two of the other three cases, weather conditions created poor visibility during the rut, and few chamois were seen and, consequently, the rut sex ratio could not be estimated. BC provided objective, high-quality counts of chamois populations and it is easy to obtain, even if its efficacy can be constrained by the need of simultaneous itineraries and an underestimation of unknown magnitude. DS does not require sampling throughout the entire area above the timberline, and generates an estimate and a confidence interval; however, calculations require some skill and sample size must be high (n > 300 groups observed to produce a CV < 15%, which represents a sampling effort at least as large as the one derived from BC. BC represents a

  2. Experimental device for chemical osmosis measurement on natural clay-rock samples maintained at in situ conditions: implications for formation pressure interpretations.

    Science.gov (United States)

    Rousseau-Gueutin, Pauline; de Greef, Vincent; Gonçalvès, Julio; Violette, Sophie; Chanchole, Serge

    2009-09-01

    In order to characterize the so-called coupled processes occurring in compacted clay rocks, the coupling coefficients must be identified. For this purpose, an original device which allows such measurement for undisturbed (natural) samples in their in situ conditions was developed. The present experimental device minimizes the fluid leaks improving the accuracy of the coupling parameter determination. Three chemical osmotic tests were performed on a cylindrical sample of Callovo-Oxfordian argilite. Room temperature variations during the chemical osmosis experiments required the implementation of temperature effects in the numerical model used for the interpretations. These variations offered the opportunity of an alternative method to estimate the compressibility of the fluid in the circuit connected to a measurement chamber located in the center of the sample. An osmotic efficiency of almost 0.2 for a concentration of 0.094 mol L(-1) is obtained for the Callovo-Oxfordian argilite. This value would explain only some part (approximately 0.10-0.15 MPa) of the overpressures (0.5-0.6 MPa) relative to the surrounding reservoirs measured in this formation. Others processes, such as thermo-osmosis, hydrodynamic boundary condition changes due to climate variations or creep behavior of the shale, could explain the remainder of the overpressures. PMID:19527907

  3. 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

  4. Diffusion of HTO, {sup 36}Cl{sup -}, {sup 125}I{sup -} and {sup 22}Na{sup +} in Opalinus Clay: Effect of Confining Pressure, Sample Orientation, Sample Depth and Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Van Loon, L.R.; Soler, J.M

    2004-02-01

    Effective diffusion coefficients (D{sub e}), rock capacity factors ({alpha}) and diffusion-accessible porosities ({epsilon}) were measured using the through-diffusion technique. Transport (diffusion) was measured both perpendicular and parallel to the bedding. Special cells that allowed the application of an axial confining pressure were designed. The pressures applied ranged from 1 to 5 MPa for Mont Terri samples and between 4 and 15 MPa for Benken samples, the upper values representing the in-situ confining pressure at both locations. The test solutions used in the experiments were synthetic Opalinus Clay pore water, which has Na and Cl as main components (Mont Terri: I = 0.39 M; Benken: I = 0.20 M). Pressure only had a small effect on the value of the effective diffusion coefficients. In the case of Mont Terri samples, increasing the pressure from 1 to 5 MPa resulted in a decrease of the effective diffusion coefficient of 20% for HTO, 27% for {sup 36}Cl{sup -}, 29% for {sup 125}I{sup -} and 17 % for {sup 22}Na{sup +}. In the case of Benken samples, increasing the pressure from 4 to 15 MPa resulted in a decrease of D{sub e} of 17% for HTO, 22% for {sup 36}Cl{sup -}, 32% for {sup 125}I{sup -} and 17 % for {sup 22}Na{sup +}. Moreover, the effective diffusion coefficients for for {sup 36}Cl{sup -}are smaller than for HTO, which is consistent with an effect arising from anion exclusion. This ion exclusion effect is smaller in samples from Mont Terri than in samples from Benken, which can be explained by the higher ionic strength of the Mont Terri water used in the experiments. The diffusion of {sup 22}Na{sup +} is similar to that of HTO in the case of Mont Terri OPA. For Benken OPA, the D{sub e} value of {sup 22}Na{sup +} is a factor of 2 higher than that of HTO. This last observation cannot be explained so far but is comparable to experimental data from ANDRA (1999) on Callovo-Oxfordian claystones from the Meuse/Haute Same site. {sup 125}I{sup -} is retarded with

  5. Norm Block Sample Sizes: A Review of 17 Individually Administered Intelligence Tests

    Science.gov (United States)

    Norfolk, Philip A.; Farmer, Ryan L.; Floyd, Randy G.; Woods, Isaac L.; Hawkins, Haley K.; Irby, Sarah M.

    2015-01-01

    The representativeness, recency, and size of norm samples strongly influence the accuracy of inferences drawn from their scores. Inadequate norm samples may lead to inflated or deflated scores for individuals and poorer prediction of developmental and academic outcomes. The purpose of this study was to apply Kranzler and Floyd's method for…

  6. 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.

  7. 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...

  8. 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)

  9. 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

  10. Isolation of high quality protein samples from punches of formalin fixed and paraffin embedded tissue blocks

    OpenAIRE

    J. Kroll(Department of Physics, University of Pennsylvania, Philadelphia PA, United States of America); Becker, K.F.; Kuphal, S; Hein, R.; Hofstädter, F; Bosserhoff, A K

    2008-01-01

    In general, it is believed that the extraction of proteins from formalin-fixed paraffin embedded samples is not feasible. However, recently a new technique was developed, presenting the extraction of non-degraded, full length proteins from formalin fixed tissues, usable for western blotting and protein arrays. In the study presented here, we applied this technique to punch biopsies of formalin fixed tissues embedded in paraffin to reduce heterogeneity of the tissue rep...

  11. A high-pressure thermal gradient block for investigating microbial activity in multiple deep-sea samples

    DEFF Research Database (Denmark)

    Kallmeyer, J.; Ferdelman, TG; Jansen, KH;

    2003-01-01

    of the sample vessels, a back-pressure system with a constant leak rate was installed. Pressure is applied through high-pressure liquid chromatography (HPLC) pumps that run in constant pressure mode with variable flow rate, thereby regulating any pressure fluctuations. The device allows incubations......Details about the construction and use of a high-pressure thermal gradient block for the simultaneous incubation of multiple samples are presented. Most parts used are moderately priced off-the-shelf components that easily obtainable. In order to keep the pressure independent of thermal expansion...... along a wide range of temperatures and pressures and can easily be modified to accommodate different experiments, either biological or chemical. As an application, we present measurements of bacterial sulfate reduction rates in hydrothermal sediments from Guyamas Basin over a wide range of temperatures...

  12. 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.

  13. 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...

  14. Relationships among low frequency (2 Hz) electrical resistivity, porosity, clay content and permeability in reservoir sandstones

    Science.gov (United States)

    Han, Tongcheng; Best, Angus I.; Sothcott, Jeremy; North, Laurence J.; MacGregor, Lucy M.

    2015-01-01

    The improved interpretation of marine controlled source electromagnetic (CSEM) data requires knowledge of the inter-relationships between reservoir parameters and low frequency electrical resistivity. Hence, the electrical resistivities of 67 brine (35 g/l) saturated sandstone samples with a range of petrophysical properties (porosity from 2% to 29%, permeability from 0.0001 mD to 997.49 mD and volumetric clay content from 0 to 28%) were measured in the laboratory at a frequency of 2 Hz using a four-electrode circumferential resistivity method with an accuracy of ± 2%. The results show that sandstones with porosity higher than 9% and volumetric clay content up to 22% behave like clean sandstones and follow Archie's law for a brine concentration of 35 g/l. By contrast, at this brine salinity, sandstones with porosity less than 9% and volumetric clay content above 10% behave like shaly sandstones with non-negligible grain surface conductivity. A negative, linear correlation was found between electrical resistivity and hydraulic permeability on a logarithmic scale. We also found good agreement between our experimental results and a clay pore blocking model based on pore-filling and load-bearing clay in a sand/clay mixture, variable (non-clay) cement fraction and a shaly sandstone resistivity model. The model results indicate a general transition in shaly sandstones from clay-controlled resistivity to sand-controlled resistivity at about 9% porosity. At such high brine concentrations, no discernible clay conduction effect was observed above 9% porosity.

  15. Geostatistical analysis of field hydraulic conductivity in compacted clay

    Energy Technology Data Exchange (ETDEWEB)

    Rogowski, A.S.; Simmons, D.E.

    1988-05-01

    Hydraulic conductivity (K) of fractured or porous materials is associated intimately with water flow and chemical transport. Basic concepts imply uniform flux through a homogeneous cross-sectional area. If flow were to occur only through part of the area, actual rates could be considerably different. Because laboratory values of K in compacted clays seldom agree with field estimates, questions arise as to what the true values of K are and how they should be estimated. Hydraulic conductivity values were measured on a 10 x 25 m elevated bridge-like platform. A constant water level was maintained for 1 yr over a 0.3-m thick layer of compacted clay, and inflow and outflow rates were monitored using 10 x 25 grids of 0.3-m diameter infiltration rings and outflow drains subtending approximately 1 x 1 m blocks of compacted clay. Variography of inflow and outflow data established relationships between cores and blocks of clay, respectively. Because distributions of outflow rates were much less and bore little resemblance to the distributions of break-through rates based on tracer studies, presence of macropores and preferential flow through the macropores was suspected. Subsequently, probability kriging was applied to reevaluate distribution of flux rates and possible location of macropores. Sites exceeding a threshold outflow of 100 x 10/sup -9/ m/s were classified as outliers and were assumed to probably contain a significant population of macropores. Different sampling schemes were examined. Variogram analysis of outflows with and without outliers suggested adequacy of sampling the site at 50 randomly chosen locations. Because of the potential contribution of macropores to pollutant transport and the practical necessity of extrapolating small plot values to larger areas, conditional simulations with and without outliers were carried out.

  16. Monoclonal autoantibodies to the TSH receptor, one with stimulating activity and one with blocking activity, obtained from the same blood sample

    OpenAIRE

    Evans, Michele; Sanders, Jane; Tagami, Tetsuya; Sanders, Paul; Young, Stuart; Roberts, Emma; Wilmot, Jane; Hu, Xiaoling; Kabelis, Katarzyna; Clark, Jill; Holl, Sabrina; Richards, Tonya; Collyer, Alastair; Furmaniak, Jadwiga; Rees Smith, Bernard

    2010-01-01

    Abstract Objective: Patients who appear to have both stimulating and blocking TSHR autoantibodies in their sera have been described but the two activities have not been separated and analysed. We now describe the isolation and detailed characterisation of a blocking type TSHR monoclonal autoantibody and a stimulating type TSHR monoclonal autoantibody from a single sample of peripheral blood lymphocytes. Design, Patients and Measurements: Two heterohybridoma cell lines secreting ...

  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. 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

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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)

  6. Mineralogical and Chemical Analysis of Fracture and Matrix Minerals in Selected Samples of the Culebra Dolomite

    International Nuclear Information System (INIS)

    Contaminant release scenarios proposed for the Waste Isolation Pilot Plant (WIPP) repository suggest that the Culebra Dolomite member of the Rustler Formation could be an important radionuclide release path. This thin, vuggy, highly fractured unit is the most transmissive geologic unit overlying the WIPP. Many of the samples obtained from drill cores in the Culebra exhibit fractures that are lined with iron-oxyhydroxide-rich and clay-rich mineral coatings. The coatings are mineralogically distinct from the rock matrix, and may have sorptive characteristics that are different from a clay-poor dolomite matrix. Where locally abundant, such coatings could affect advective/diffusive exchange between matrix blocks and fractures and the accessible mineral surface area available for radionuclide adsorption. Clay minerals are present in the matrix and as fracture coatings in the samples from all the drill core locations examined in this study. Visual examination of rock sample surfaces in the H-19b7 core suggests that at least 7% of the total fracture surface area is coated with iron oxhydroxides or clays. In the samples from H-19b7, the amount of clay disseminated in the matrix varies from <1% to approximately12 % by weight, and generally increases with stratigraphic height within the unit. In a suite of samples obtained from 12 other locations in the vicinity of the WIPP site, matrix samples from the Culebra contain 0.6--7% clay. These samples were taken from the more transmissive lower two-thirds of the unit (Culebra Units 2-4) which was considered to be the accessible portion of the unit in the WIPP Compliance Certification Application (CCA). Clay minerals also occur as clay-rich laminae and partings with the geometries of primary sedimentary structures and dissolution residues. Such partings are the loci of bedding plane fractures, and have the heaviest clay coatings found in the unit. Crosscutting fractures also commonly exhibit clay mineral coatings, but these are

  7. Fault transmissibility in clastic-argillaceous sequences controlled by clay smear evolution

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The mechanical entrainment of clays and shales in fault zones of sedimentary sequences can exert fundamental control on fault-permeability. To estimate the influence of entrained clay bands on fluid flow, semi-empirical fault-seal algorithms are being used for hydrocarbon exploration (e.g. Yielding et al., 1997) and CO2 storage assessment (e.g. Bretan et al., 2011). To estimate clay distribution in the fault zone, these algorithms do not consider material properties or deformation conditions at the time of faulting, but rather they rely on the simplified assumption that fault gouge composition at any point along the fault reflects the 'mean' clay fraction of the slipped interval. Whether individual clay bands are breached or are continuous is not evaluated, yet this could have a dramatic effect on fault transmissibility. In this study, the sealing capacity of clay smears evolving in sealed direct shear experiments of initially intact sandstone-clay-stone sequences was quantified to large displacements up to more than ten times the thickness of the clay layer. A new type of direct shear cell was specifically designed for these experiments (Giger et al., 2011). The sample blocks consisted of a pre-consolidated clay-rich 'seal' layer, which was embedded and synthetically cemented in 'reservoir' quartz sand. The mineralogy and mechanical properties of the clay layer and the reservoir sandstones were constrained in geomechanical tests. Discrete element modelling (DEM) was carried out in parallel to investigate a wider range of deformation conditions, and to explore the possibility to upscale the analogue test results. The fluid flow response across the fault zone could be monitored continuously during deformation. A tracer was also added to the clay layer, and the finite 3D smear structure could be resolved (using a medical CT scanner) and related to the flow response (Ciftci et al., 2011). Displacement at which seals

  8. Uniaxial backfill block compaction

    International Nuclear Information System (INIS)

    The main parts of the project were: to make a literature survey of the previous uniaxial compaction experiments; do uniaxial compaction tests in laboratory scale; and do industrial scale production tests. Object of the project was to sort out the different factors affecting the quality assurance chain of the backfill block uniaxial production and solve a material sticking to mould problem which appeared during manufacturing the blocks of bentonite and cruched rock mixture. The effect of mineralogical and chemical composition on the long term functionality of the backfill was excluded from the project. However, the used smectite-rich clays have been tested for mineralogical consistency. These tests were done in B and Tech OY according their SOPs. The objective of the Laboratory scale tests was to find right material- and compaction parameters for the industrial scale tests. Direct comparison between the laboratory scale tests and industrial scale tests is not possible because the mould geometry and compaction speed has a big influence for the compaction process. For this reason the selected material parameters were also affected by the previous compaction experiments. The industrial scale tests were done in summer of 2010 in southern Sweden. Blocks were done with uniaxial compaction. A 40 tons of the mixture of bentonite and crushed rock blocks and almost 50 tons of Friedland-clay blocks were compacted. (orig.)

  9. Application of k0-based internal monostandard NAA for large sample analysis of clay pottery. As a part of inter comparison exercise

    International Nuclear Information System (INIS)

    As a part of inter comparison exercise of an IAEA Coordinated Research Project on large sample neutron activation analysis, a large size and non standard geometry size pottery replica (obtained from Peru) was analyzed by k0-based internal monostandard neutron activation analysis (IM-NAA). Two large size sub samples (0.40 and 0.25 kg) were irradiated at graphite reflector position of AHWR Critical Facility in BARC, Trombay, Mumbai, India. Small samples (100-200 mg) were also analyzed by IM-NAA for comparison purpose. Radioactive assay was carried out using a 40 % relative efficiency HPGe detector. To examine homogeneity of the sample, counting was also carried out using X-Z rotary scanning unit. In situ relative detection efficiency was evaluated using gamma rays of the activation products in the irradiated sample in the energy range of 122-2,754 keV. Elemental concentration ratios with respect to Na of small size (100 mg mass) as well as large size (15 and 400 g) samples were used to check the homogeneity of the samples. Concentration ratios of 18 elements such as K, Sc, Cr, Mn, Fe, Co, Zn, As, Rb, Cs, La, Ce, Sm, Eu, Yb, Lu, Hf and Th with respect to Na (internal mono standard) were calculated using IM-NAA. Absolute concentrations were arrived at for both large and small samples using Na concentration, obtained from relative method of NAA. The percentage combined uncertainties at ±1 s confidence limit on the determined values were in the range of 3-9 %. Two IAEA reference materials SL-1 and SL-3 were analyzed by IM-NAA to evaluate accuracy of the method. (author)

  10. 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 ...

  11. 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

  12. 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.

  13. 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

  14. 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)

  15. Technetium migration in natural clays

    International Nuclear Information System (INIS)

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

  16. Regional Sampling of Mantle Peridotites in Serpentinite Blocks Collected from Serpentinite Bodies in the San Francisco Bay Area, California: Petrological Trends

    Science.gov (United States)

    Lewis, M.; Kirby, S. H.

    2015-12-01

    We have collected and investigated 278 ultramafic and related rock samples from 18 polygonal-block -and- sheared-matrix-type serpentinite bodies in the Coast Ranges in the San Francisco Bay Area. These sites include Ring Mountain in the north to Silver Creek near San Jose in the south, spanning nearly 100 km of Coast Range geology. These bodies show extensive variation in volume ratios of serpentinite blocks (some including peridotite minerals) to sheared matrix, in peridotite mineral modes, in the degrees of weathering, in the proportions of peridotite minerals versus alteration minerals, and in the degree of late-stage brittle deformation. However, we found remarkable coherence in the serpentinite alteration mineralogy and our samples bear a strong resemblance to those in the Redwood City serpentinite body studied recently by Uno and Kirby (GRL submitted). In particular, we see mineralogical and geochemical evidence for multiple stages of alteration of the original peridotite minerals that reflect partial peridotite alteration, likely in the mantle, and then a later reaction to lizardite + magnetite in the crust. These reactions are followed by localized late-stage partial alteration of serpentinite to silica minerals and magnesite by carbonated water. Our findings suggest that the mantle sources of this type of partially-serpentinized peridotite in this section of the Coast Ranges are remarkably similar and that the processes leading to later-stage alteration reactions have operated repeatedly over the area that we sampled. Internal deformation in these bodies during later stages of alteration probably occurred during ascent through the crust, as reflected by sheared lizardite skins on the serpentinite blocks that we collected. We put forward several working hypotheses that provide insights into the origins and geologic histories of these rocks.

  17. 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.

  18. Development of new ceramic materials from the waste of serpentinite and red clay

    International Nuclear Information System (INIS)

    The objective of this work is to develop new ceramic materials using serpentine and glass waste and clay red. The raw materials were characterized through morphological, granulometric, mineralogical and chemical analysis. Six formulations have been developed based on the serpentine and red clay, which three of the six compositions have been adjusted with the addition of residual glass. The ceramic bodies were formed by uniaxial pressing and subjected to burn in an electric oven at temperatures of 1100 ° C, 1200 ° C, 1250 ° C and 1300 ° C. The ceramic samples obtained this way were characterized according to their physical properties (specific mass and linear retraction) and the mechanical (three points bending strength). The final properties varied according to the proportions of raw materials and firing temperature. In general, the different formulations fit the standards for traditional ceramics such as tiles and ceramic blocks. (author)

  19. 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

  20. 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...

  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. Fuel-containing particles released from the fourth block of the Chernobyl NPP in soil samples of the Bryansk district

    International Nuclear Information System (INIS)

    Autoradiography is used to identify radioactive microparticles in the small soil fraction. Microparticles containing α-emitters are detected. Radiochemical and α-spectrometric methods revealed the nature of the α-tracks. The contents of Pu and 241Am in the studied sample are estimated. The data confirm the open-quotes Chernobyl originclose quotes of the contaminated Bryanski soil (Novozybkovsk region)

  3. 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

  4. 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

  5. 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.

  6. A preliminary study on titanium-clay interactions

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Posiva and SKB are developing a horizontal disposal design alternative, termed KBS-3H. In this design alternative, modules of a Cu-waste canister surrounded by bentonite blocks is placed in a perforated steel cylinder, a so-called supercontainer (SC), before emplacement in the deposition drifts. The current design for the SC is based on carbon steel. But because corrosion will lead to high hydrogen levels and iron-clay interactions, alternative materials are also being considered. A promising alternative are Ti alloys which display high strength and are known to behave as chemically inert materials under variety of conditions. Also for the Ti alloys, both the corrosion rate and interaction behaviour with other components in the drift needs to be known. In particular, it needs to be demonstrated that corrosion-derived Ti has no significant detrimental effects on the bentonite buffer which is one main barrier within the KBS-3H concept. Unfortunately, the benign inert behaviour of Ti makes it difficult to perform meaningful experiments. Hence, it is not surprising that so far, very little research work on this topic has been carried out and experience is very limited. A preliminary batch-type investigation has been launched to shed more light on Ti-clay interaction processes and on the Ti species resulting from these interactions. A series of experiments including purified MX-80 bentonite or synthetic 'Ti-free' montmorillonite were mixed with metallic Ti nano-powder or foil in 0.1 M NaCl solutions at different pH and temperature conditions. After several months, solid and solute samples from the first set of tests were analyzed by wet chemistry and spectroscopic methods. Ti speciation was analyzed with XAS combined with XRF as elemental mapping tool. A further series of tests will be analyzed in the near future. In addition to reacted samples, a number of reference and starting materials (e.g. MX-80, Rokle

  7. Block clustering with collapsed latent block models

    OpenAIRE

    Wyse, Jason; Friel, Nial

    2010-01-01

    We introduce a Bayesian extension of the latent block model for model-based block clustering of data matrices. Our approach considers a block model where block parameters may be integrated out. The result is a posterior defined over the number of clusters in rows and columns and cluster memberships. The number of row and column clusters need not be known in advance as these are sampled along with cluster memberhips using Markov chain Monte Carlo. This differs from existing work on latent bloc...

  8. 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.

  9. 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

  10. 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...

  11. 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...

  12. 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)

  13. 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

  14. Application of polyhydroxybutyrate-b-polyethyleneglycol (a block co-polymer) for solid phase extraction of lead and copper in different food samples

    International Nuclear Information System (INIS)

    In present work, a new adsorbent, polyhydroxybutyrate-b-polyethyleneglycol (block copolymer) was used for the preconcentration and separation of copper (Cu) and lead (Pb) ions without consuming expensive complexing reagent. The influence of various parameters like pH, adsorbent amount, and rates of flow of eluent, sample and sample volumes has been investigated. The polymer does not interact with alkaline earth metals, transition metals, alkaline, and few anions. The enrichment factor 50 was achieved in this method. The detection limit of method was found to be 0.36 micro g L/sup 1/ and 1.93 micro g L/sup 1/ for copper and lead, respectively. The recovery values of both analytes were found >96% and relative standard deviations (RSD) for all experiments were found less than 5%. The present method was validated by the analysis of Cu and Pb contents in various related certified reference materials (CRM) like; NIST SRM 1515 Apple leaves, IAEA -336 Lichen and GBW-07605 Tea. Found results and CRM values were precise and accurate. This developed method was then successfully applied for analysis of Cu and Pb in tap and bottled mineral water and real food samples. (author)

  15. 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.

  16. 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

  17. Molecular testing guidelines for lung adenocarcinoma: Utility of cell blocks and concordance between fine-needle aspiration cytology and histology samples

    Directory of Open Access Journals (Sweden)

    Jonas J. Heymann

    2014-01-01

    Full Text Available Background: Lung cancer is a leading cause of mortality, and patients often present at a late stage. More recently, advances in screening, diagnosing, and treating lung cancer have been made. For instance, greater numbers of minimally invasive procedures are being performed, and identification of lung adenocarcinoma driver mutations has led to the implementation of targeted therapies. Advances in molecular techniques enable use of scant tissue, including cytology specimens. In addition, per recently published consensus guidelines, cytology-derived cell blocks (CBs are preferred over direct smears. Yet, limited comparison of molecular testing of fine-needle aspiration (FNA CBs and corresponding histology specimens has been performed. This study aimed to establish concordance of epidermal growth factor receptor (EGFR and Kirsten rat sarcoma (KRAS virus homolog testing between FNA CBs and histology samples from the same patients. Materials and Methods: Patients for whom molecular testing for EGFR or KRAS was performed on both FNA CBs and histology samples containing lung adenocarcinoma were identified retrospectively. Following microdissection, when necessary, concordance of EGFR and KRAS molecular testing results between FNA CBs and histology samples was evaluated. Results: EGFR and/or KRAS testing was performed on samples obtained from 26 patients. Concordant results were obtained for all EGFR (22/22 and KRAS (17/17 mutation analyses performed. Conclusions: Identification of mutations in lung adenocarcinomas affects clinical decision-making, and it is important that results from small samples be accurate. This study demonstrates that molecular testing on cytology CBs is as sensitive and specific as that on histology.

  18. 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

  19. 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…

  20. 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...

  1. 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.

  2. 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...

  3. 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)

  4. 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.

  5. Results of brine flow testing and disassembly of a crushed salt/bentonite block seal at the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    The Small-Scale Seal Performance Tests, Series C, a set of in situ experiments conducted at the Waste Isolation Pilot Plant, are designed to evaluate the performance of various seal materials emplaced in large (0.9-m-diameter) boreholes. This report documents the results of fluid (brine) flow testing and water and clay content analyses performed on one emplaced seal comprised of 100% salt blocks and 50%/50% crushed salt/bentonite blocks and disassembled after nearly three years of brine injection testing. Results from the water content analyses of 212 samples taken from within this seal show uniform water content throughout the 50%/50% salt/bentonite blocks with saturations about 100%. Clay content analyses from the 100% salt endcaps of the seal show a background clay content of about 1% by weight uniformly distributed, with the exception of samples taken at the base of the seal at the borehole wall interface. These samples show clay contents up to 3% by weight, which suggests some bentonite may have migrated under pressure to that interface. Results of the brine-flow testing show that the permeability to brine for this seal was about 2 to 3 x 10-4 darcy (2 to 3 x 10-16 m2)

  6. Clay mineral distribution in surface sediments of the South Atlantic: sources, transport, and relation to oceanography

    OpenAIRE

    Petschick, Rainer; Kuhn, Gerhard; Gingele, Franz

    1996-01-01

    Surface samples, mostly from abyssal sediments of the South Atlantic, from parts of the equatorial Atlantic, and of the Antarctic Ocean, were investigated for clay content and clay mineral composition. Maps of relative clay mineral content were compiled, which improve previous maps by showing more details, especially at high latitudes. Large-scale relations regarding the origin and transport paths of detrital clay are revealed. High smectite concentrations are observed in abyssal regions, pri...

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

    OpenAIRE

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

    2015-01-01

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

  8. Thermal Performance of Hollow Clay Brick with Low Emissivity Treatment in Surface Enclosures

    OpenAIRE

    Roberto Fioretti; Paolo Principi

    2014-01-01

    External walls made with hollow clay brick or block are widely used for their thermal, acoustic and structural properties. However, the performance of the bricks frequently does not conform with the minimum legal requirements or the values required for high efficiency buildings, and for this reason, they need to be integrated with layers of thermal insulation. In this paper, the thermal behavior of hollow clay block with low emissivity treatment on the internal cavity surfaces has been invest...

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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)

  14. Heart Block

    Science.gov (United States)

    ... the signal causes the heart to contract and pump blood. Heart block occurs if the electrical signal is ... degree heart block limits the heart's ability to pump blood to the rest of the body. This type ...

  15. 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

  16. 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

  17. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  18. 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...

  19. Synthesis and application of a thermo sensitive tri-block copolymer as an efficient sample treatment technique for preconcentration and ultra-trace detection of lead ions

    International Nuclear Information System (INIS)

    We have designed and synthesized a thermo sensitive tri-block copolymer for selective trace extraction of Pb(II) ions from biological and food samples. The polymer was characterized by Fourier transform IR and NMR spectroscopy, and by gel permeation chromatography. The critical aggregation concentration and lower critical solution temperature were determined via fluorescence and UV spectrophotometry, respectively. The effects of solution pH value, amount of copolymer, of the temperature on extraction and on phase separation, and of the matrix on the extraction of Pb(II) were optimized. Pb(II) ions were then quantified by FAAS. The use of this copolymer resulted in excellent figures of merit including a calibration plot extending from 0.5 to 160 μg L−1 (with an R2 of >0.99), a limit of detection (LOD) as low as 90 pg L−1, an extraction efficiency of >98 %, and relative standard deviations of <4 % for eight separate extraction experiments. (author)

  20. 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)

  1. 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)

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. Origin of clay-mineral variation in Wisconsinan age sediments from the Lake Michigan basin

    Energy Technology Data Exchange (ETDEWEB)

    Monaghan, G.W. (Geocomp Research, Eaton, NY (United States)); Larson, G.J. (Michigan State Univ., East Lansing, MI (United States). Dept. of Geological Sciences)

    1994-04-01

    Drift samples collected in Wisconsin and Michigan from exposures representative of the Wisconsinan stratigraphy of the Lake Michigan Lobe indicate that clay mineral and shale lithology systematically vary between successive till sheets as a result of differential erosion of two unique source beds: shale bedrock, rich in 10[angstrom] clay (illite) and pre-existing drift (particularly lacustrine clay), depleted in 10[angstrom] clay. A general increase in relative amounts of 10[angstrom] clay and shale clasts begins with early or middle Wisconsinan (Altonian) Glenn Shores till and continues through late Wisconsinan (Woodfordian) Ganges-New Berlin till and Saugatuck-Oak Creek till. Both 10[angstrom] clay and shale decrease in post Mackinaw (late Woodfordian) Interstade Ozaukee-Haven and Two Rivers tills. Clay minerals in till rich in 10[angstrom] clay (Saugatuck-Oak Creek) were derived mainly from extensive erosion and comminution of shale whereas those in tills depleted in 10[angstrom] clay (Ganges-New Berlin, Ozaukee-Haven, and Two Rivers) were eroded mainly from lacustrine clay. Because it is compositionally dissimilar to either the shale or lake clay source and relatively rich in kaolinite, clay minerals in early-middle Wisconsinan Glenn Shores till may have been derived from Sangamon saprolite eroded during an early post-Sangamon ice advance. Variations in source bed erosion and subsequent changes in till lithology result either from depletion of the source bed (Glenn Shores till) or from progressively eroding drift mantling shale outcrops (unroofing) during successive late Wisconsinan ice advances.

  8. 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

  9. 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.

  10. 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

  11. 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...

  12. 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...

  13. 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

  14. Clay resources in the Netherlands

    NARCIS (Netherlands)

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

    2007-01-01

    Clay is a common lithology in the Dutch shallow subsurface. It is used in earth constructions such as dikes, and as raw material for the 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

  15. 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

  16. 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...

  17. 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...

  18. 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

  19. On the tectonic evolution of the Tyrrhenian basin: new data from detrital zircons sampled in the Sardinia-Corsica Block and in the Calabria-Peloritain Arc

    Science.gov (United States)

    Pavanetto, Pamela; Funedda, Antonio; Matteini, Massimo; Loi, Alfredo

    2013-04-01

    Geodynamic models and palinspastic reconstructions of pery-Thyrrenian terranes in the Western Mediterranean area are still extremely complex and speculative (Stampfly & Borel 2002, Trombetta et al., 2004; Alvarez & Shimabukuro, 2009; Carminati et al., 2012).A contribute can be done by considering the relationships between Sardinia-Corsica Block (SCB) and Calabria-Peloritain Arc (CPA). They shared a similar Variscan evolution and were the western part of the Briançonnais plate until the opening of the Algero-Provençal Basin during Burdigalian and then were separated in Late Tertiary during the spreading of South-Tyrrhenian Basin. During this period the CPA moved southeastward, with respect to the SCB, driven by a progressive roll-back of the subducted slab. However, is still ambiguous if the CPA was a single terrane during the Middle and Late Tertiary (Amodio Morelli et alii, 1976) or formed by the amalgamation of two or more continental "terranes" that collided during the Tertiary (Bonardi et al., 1980; Scandone, 1982; Alvarez & Shimabukuro, 2009). The data about the paleo-tectonic linkages, the terranes derivations, and the tectonic setting of the SCB and CPA as peri-Tyrrhenian blocks during Tertiary are still poor. Some evidence of their early evolution could be found in coeval Tertiary deposits cropping out both in the SCB and CPA. These deposits represent the early stage of the estensional event developed in the Tyrrhenian region during late Oligocene-Lower Miocene in a broader regional context dominated by the opening of Atlantic Ocean and the resulting convergence of Europe and Apulia microplate (Oggiano et al., 2009). To improve the knowledge on this topic, combined U-Pb and Lu-Hf analyses on zircons from Tertiary detrital sediments from Sardinia, Corsica, and both North and South Calabria have been performed using a Thermo-Fisher Neptune MC-ICP-MS coupled with a Nd:YAG UP213 New Wave laser ablation system, at the Laboratory of Geochronology of the

  20. 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

  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. 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)

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

    Science.gov (United States)

    Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun

    2013-01-01

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

  4. 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)

  5. 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.

  6. Macro-and Micro- Properties of Two Natural Marine Clays in China

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming-jing; PENG Li-cai; ZHU He-hua; LIN Yi-xi; HUANG Liang-ji

    2009-01-01

    In this paper,macro- and micro- properties of natural marine clay in two different and representative regions of China are investigated in detail.In addition to in-situ tests,soil samples are collected by use of Shelby tubes for laboratory examination in Shanghai and Zhuhai respectively,two coastal cities in China.In the laboratory tests,macro-properties such as consolidation characteristics and undrained shear strength are measured.Moreover,X-ray diffraction test,scanning electron microscope test,and mercury intrusion test are carried out for the investigation of their micro-properties including clay minerals and microstructure.The study shows that:(1) both clays are Holocene series formations,classified as either normal or underconsolidated soils.The initial gradient of the stress-strain curves shows their increase with increasing consolidation pressure;however,the Shanghai and the Zhuhai clays are both structural soils with the latter shown to be more structured than the former.As a result,the Zhuhai clay shows strain softening behavior at low confining pressures,but strain hardening at high pressures.In contrast,the Shanghai clay mainly manifests strain-hardening.(2) An activity ranges from 0.75 to 1.30 for the Shanghai marine clay and from 0.5 to 0.85 for the Zhuhai marine clay.The main clay mineral is illite in the Shanghai clay and kaolinite in the Zhuhai clay.The Zhuhai clay is mainly characterized by a flocculated structure,while the typical Shanghai clay shows a dispersed structure.The porous structure of the Shanghai clay is characterized mainly by large and medium-sized pores,while the Zhuhai clay porous structure is mainly featreed by small and medium-sized pores.The differences in their macro- and micro- properties can he attributed to different sedimentation environments.

  7. The Block-block Bootstrap: Improved Asymptotic Refinements

    OpenAIRE

    Donald W.K. Andrews

    2002-01-01

    The asymptotic refinements attributable to the block bootstrap for time series are not as large as those of the nonparametric iid bootstrap or the parametric bootstrap. One reason is that the independence between the blocks in the block bootstrap sample does not mimic the dependence structure of the original sample. This is the join-point problem. In this paper, we propose a method of solving this problem. The idea is not to alter the block bootstrap. Instead, we alter the original sample sta...

  8. 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.

  9. 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.

  10. 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.

  11. Clay mineral recrystalization in pottery and TL fine-grain dating

    International Nuclear Information System (INIS)

    Prehistoric pottery samples from North Germany show considerable degrees of clay mineral recrystallization which increases with age. This phenomenon may affect the realiability of TL fine grain dating. Therefore, a joint test programme has been initiated which combines clay mineralogy and thermoluminescence studies on some Norht German pottery samples. First results are presented. (author)

  12. Clay mineral distribution in surface sediments between Indonesia and NW Australia - source and transport by ocean currents

    OpenAIRE

    Gingele, F. X.; De Deckker, P.; Hillenbrand, C.-D.

    2001-01-01

    The clay mineral distribution in sediments between Indonesia and NW Australia has been assessed on the basis of 166 core-top samples. Clay mineral assemblages are closely related to the geology and weathering regime of the adjacent hinterland and allow the distinction of four clay mineral provinces. Three provinces, Western, Central and Eastern Province are situated along the Indonesian Islands Arc, from Sumatra in the west to Timor in the east. Illite is the major clay mineral of the Western...

  13. Blocked randomization with randomly selected block sizes.

    Science.gov (United States)

    Efird, Jimmy

    2011-01-01

    When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes. PMID:21318011

  14. Blocked Randomization with Randomly Selected Block Sizes

    Directory of Open Access Journals (Sweden)

    Jimmy Efird

    2010-12-01

    Full Text Available When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  15. Evaluation of the medicinal use of clay minerals as antibacterial agents.

    Science.gov (United States)

    Williams, Lynda B; Haydel, Shelley E

    2010-07-01

    Natural clays have been used to heal skin infections since the earliest recorded history. Recently our attention was drawn to a clinical use of French green clay (rich in Fe-smectite) for healing Buruli ulcer, a necrotizing fasciitis ('flesh-eating' infection) caused by Mycobacterium ulcerans. These clays and others like them are interesting as they may reveal an antibacterial mechanism that could provide an inexpensive treatment for this and other skin infections, especially in global areas with limited hospitals and medical resources.Microbiological testing of two French green clays, and other clays used traditionally for healing, identified three samples that were effective at killing a broad-spectrum of human pathogens. A clear distinction must be made between 'healing clays' and those we have identified as antibacterial clays. The highly adsorptive properties of many clays may contribute to healing a variety of ailments, although they are not antibacterial. The antibacterial process displayed by the three identified clays is unknown. Therefore, we have investigated the mineralogical and chemical compositions of the antibacterial clays for comparison with non-antibacterial clays in an attempt to elucidate differences that may lead to identification of the antibacterial mechanism(s).The two French green clays used to treat Buruli ulcer, while similar in mineralogy, crystal size, and major element chemistry, have opposite effects on the bacterial populations tested. One clay deposit promoted bacterial growth whereas another killed the bacteria. The reasons for the difference in antibacterial properties thus far show that the bactericidal mechanism is not physical (e.g., an attraction between clay and bacteria), but by a chemical transfer or reaction. The chemical variables are still under investigation.Cation exchange experiments showed that the antibacterial component of the clay can be removed, implicating exchangeable cations in the antibacterial process

  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. Clay-mineral suites, sources, and inferred dispersal routes: Southern California continental shelf

    Science.gov (United States)

    Hein, J.R.; Dowling, J.S.; Schuetze, A.; Lee, H.J.

    2003-01-01

    Clay mineralogy is useful in determining the distribution, sources, and dispersal routes of fine-grained sediments. In addition, clay minerals, especially smectite, may control the degree to which contaminants are adsorbed by the sediment. We analyzed 250 shelf sediment samples, 24 river-suspended-sediment samples, and 12 river-bed samples for clay-mineral contents in the Southern California Borderland from Point Conception to the Mexico border. In addition, six samples were analyzed from the Palos Verdes Headland in order to characterize the clay minerals contributed to the offshore from that point source. The clay-mineral suite for the entire shelf sediment data set (26% smectite, 50% illite, 24% kaolinite+chlorite) is closely comparable to that for the mean of all the rivers (31% smectite, 49% illite, 20% kaolinite+chlorite), indicating that the main source of shelf fine-grained sediments is the adjacent rivers. However, regional variations do exist and the shelf is divided into four provinces with characteristic clay-mineral suites. The means of the clay-mineral suites of the two southernmost provinces are within analytical error of the mineral suites of adjacent rivers. The next province to the north includes Santa Monica Bay and has a suite of clay minerals derived from mixing of fine-grained sediments from several sources, both from the north and south. The northernmost province clay-mineral suite matches moderately well that of the adjacent rivers, but does indicate some mixing from sources in adjacent provinces.

  18. 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.

  19. 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...

  20. 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...

  1. 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...

  2. 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.

  3. 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.

  4. Assessment of potential Rio Grande do Norte, Brazil, clays when subjected to high rates of heating; Avaliacao da potencialidade de argilas do Rio Grande do Norte quando submetidas a elevadas taxas de aquecimento

    Energy Technology Data Exchange (ETDEWEB)

    Filgueira, R.L.; Pereira, L.M.; Dutra, R.P.S.; Nascimento, R.M. [Universidade Federal do Rio Grande do Norte (DEMat/CT/UFRN), Natal, RN (Brazil). Centro de Tecnologia. Dept. de Engenharia de Materiais

    2009-07-01

    In this work we study three clays of the state of Rio Grande do Norte, Brazil, to evaluate the potential them when subjected to high rates of heating. The samples were formed by pressing and subject to rates of 5 deg C / min, 10 deg C / min and 15 deg C / min, with temperature of 950 deg C. This study determined the technological properties of the samples. The mineralogical composition was identified by X-ray diffraction. The chemical composition was determined by Xray fluorescence. The Atterberg limits, were used to classify the samples on the plasticity. Were also performed: dilatometry, size analysis and scanning electron microscopy. The examination of the processing variables and the intrinsic characteristics of each material indicates that the RX clay showed the best results for the manufacture of blocks and tiles. The techniques used in this study were efficient and the initial objectives were achieved. (author)

  5. 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...

  6. 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)

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

    International Nuclear Information System (INIS)

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

  8. 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...

  9. 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%...

  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. On the decay of strength in Guilin red clay with cracks

    Directory of Open Access Journals (Sweden)

    Yi Li

    2015-10-01

    Full Text Available In order to research the effect of cracks in red clay on shear strength through dry-wet cycle test, the experimenters used imaging software and a mathematical model to determine fractal dimension and crack ratio of surface cracks in red clay in Guilin, China. After each dry-wet cycle, direct shear tests were carried out on the sample, and such variables as matrix suction on the crack propagation process of red clay were analyzed. The mechanics model was established and obtained the critical condition of soil cracks. The results show that with the increase in the number of dry-wet cycles the shear strength of the samples would decrease. But the rule of shear strength of sample 3 is slightly different from samples 1 and 2. The shear strength of red clay has a good correlation with fractal dimension and crack ratio, which could be an identification index of the strength of red clay

  12. X-Ray Fluorescence and Mossbauer Spectroscopic Characterization of Clays around Khartoum

    International Nuclear Information System (INIS)

    A total of 69 clay samples were collected from the area around Khartoum province. A complete chemical analysis was carried out using different techniques. It was then revealed that there no significant differences in the chemical composition between most of the samples. X-ray diffraction studies showed that the clay samples were mainly of the smectite group with traces of the kaolinite one. The determination of total iron content as well as the concentration of Fe, Fe ions and the free iron oxides were accomplished by Mossbauer spectroscopy. The lower limits of the Fe2O3: Al2O3 ratio for each of montronite and montmorillonite clay minerals were determined. A ratio of 1:1.5 indicated a montmorillonite clay mineral. The samples studied were classified as nontronite clay minerals. (author)

  13. Ghost Block

    OpenAIRE

    Webb, Neil

    2011-01-01

    Filmed on the English south coast 'Ghost Block' depicts the uncanny and eerie atmosphere at the site of a WW2 coastal defence line. The concrete cubes were used as an anti-invasion blockade against potential landing forces. This protection line now slowly decaying and becoming enmeshed into the environment still acts as a defence to repel unwanted visitors. The area is a natural reserve to nesting birds that often lay eggs directly onto the beach surface. The blocks act as a final barrier ...

  14. Fingerprint Image Watermarking Algorithm Based on Block Compressed Sensing with Variable Sampling Rates%一种分块压缩感知变采样率的指纹图像水印算法

    Institute of Scientific and Technical Information of China (English)

    赵慧民; 蔡君; 魏文国

    2014-01-01

    Content protection of fingerprint image is an important application field for information securi-ty,and robustness is a key techniques.An actualization method of block compressed sensing watermark-ing (BCSW)with variable sampling rates is proposed to aim at content security protection problem.First-ly,the watermark image of fingerprint is performed discrete wavelet transform (DWT),and divided into several sub block in which the block size can be adjusted according to structure features of the blocking image.Secondly,block-based compressed-sensing sampling is deployed independently within each sub-band of each decomposition level of a wavelet transform of an image.Finally,the formed watermark data are embedded into all sub-blocks of the LLn sub-band of the transformed host image by using quantization technique.Experimental results show that the introduction of compressed sensing theory improves the ro-bustness and security of the protected fingerprint image.%指纹图像水印是数字内容保护的重要应用领域,而鲁棒性是其实现的关键技术。针对指纹数字内容的水印化保护问题,提出一种分块压缩感知水印(Block compressed sensing watermark,BCSW)变采样率实现方法。首先对指纹图像进行DWT变换,并对每级每个子带分别进行分块压缩感知测量处理,并将观测值作为水印信息嵌入到载体图像。实验结果表明,相对于联合DWT-DCT和DCT以及SCD水印算法,BCSW算法具有更好的鲁棒性,同时具有更高的准确性和安全性。

  15. Impact of Oriented Clay Particles on X-Ray Spectroscopy Analysis

    Science.gov (United States)

    Lim, A. J. M. S.; Syazwani, R. N.; Wijeyesekera, D. C.

    2016-07-01

    Understanding the engineering properties of the mineralogy and microfabic of clayey soils is very complex and thus very difficult for soil characterization. Micromechanics of soils recognize that the micro structure and mineralogy of clay have a significant influence on its engineering behaviour. To achieve a more reliable quantitative evaluation of clay mineralogy, a proper sample preparation technique for quantitative clay mineral analysis is necessary. This paper presents the quantitative evaluation of elemental analysis and chemical characterization of oriented and random oriented clay particles using X-ray spectroscopy. Three different types of clays namely marine clay, bentonite and kaolin clay were studied. The oriented samples were prepared by placing the dispersed clay in water and left to settle on porous ceramic tiles by applying a relatively weak suction through a vacuum pump. Images form a Scanning Electron Microscope (SEM) was also used to show the comparison between the orientation patterns of both the sample preparation techniques. From the quantitative analysis of the X-ray spectroscopy, oriented sampling method showed more accuracy in identifying mineral deposits, because it produced better peak intensity on the spectrum and more mineral content can be identified compared to randomly oriented samples.

  16. 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

  17. Epidural block

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home ... It numbs or causes a loss of feeling in the lower half your body. This lessens the pain of contractions during childbirth. An epidural block may also be used to ...

  18. Imaging techniques in clay sciences: a key tool to go a step further

    International Nuclear Information System (INIS)

    the need to study microstructure of clay-rocks and clay based materials from multi-scale techniques and multiple scientific disciplines. Nevertheless at the end of the 90's, several scientific and/or technological bottlenecks, like the imaging the clays in 3D, limited our capacity to bridge small scale processes to macro-scale behaviors and properties. Over the last decade, R and D programs on nuclear waste disposal have tackled many issues to go further in our understanding of clays. Through different results and current studies, we have reviewed various developments and improvements on imaging techniques and their applications on clay-rocks and clay based materials currently under investigations. The presentation will address successively the different questions asked at each step, from the acquisition to the use of the data: - improvement and development of sampling and microstructure preservation methods to image undisturbed samples, - emergence of 3D techniques (X-ray microtomography, FIB/SEM...) and their application to clay based materials and clay rocks, - improvement of image acquisition and treatment of 2D/3D images, - development of multi-scale methodologies, - cross-cutting between imaging and analytical techniques to get quantitative information on pore and mineral spatial distribution, - imaging in 2D/3D the microstructure of clay materials under THMC conditions and environmental conditions, - extraction of quantitative information from image analysis using statistical approaches or cross-correlation to quantitative techniques, - correlation between microstructure characteristic parameters and macroscopic properties, - modeling of multi-scale THMC processes using data extracted from images. Conclusions drawn up from this review show up that imaging techniques have progressively turned into an essential tool to support THMC experimental or numerical studies in a sense that they have gradually evolved from a qualitative observation mean to a quantitative

  19. 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)

  20. Influence of Laurolactam Content on the Clay Intercalation of Polyamide 6,12/Clay Nanocomposites Synthesized by Open Ring Anionic Polymerization

    Directory of Open Access Journals (Sweden)

    E. N. Cabrera Álvarez

    2012-01-01

    Full Text Available In situ anionic homo- and copolymerization of caprolactam (CL and laurolactam (LL with sodium montmorillonite clay (NaMMT was carried out using two different initiators, sodium caprolactamate (CLNa and caprolactam magnesium bromide (CLMgBr. Degree of conversion and final molecular weight were used to assess the advancement and efficiency of the polymerization reaction and X-ray diffraction and electron microscopy were used to evaluate the sodium montmorillonite clay intercalation/exfoliation. The use of CLNa as initiator produced a higher conversion degree and molecular weight than the use of CLMgBr. Through DSC, it was observed that CLNa and CLMgBr tended to produce random and block copolymer structures, respectively, and either random or block, this eventually has an effect on the clay dispersion within the polymer matrix. In all cases, increasing the LL content produced a decrease in the conversion degree and in the molecular weight of the resulting polymer.

  1. 基于 DWT 的多尺度分块变采样率压缩感知图像重构算法%An Image Variable Sampling and Reconstruction Algorithm Based DWT Multiscale Block Compressed Sensing

    Institute of Scientific and Technical Information of China (English)

    蒋业文; 于昕梅

    2013-01-01

    At present, utilizing Compressed Sensing (CS) theory to improve image quality of recon-structions is a research focus of image process technology .By deploying block-based CS variable sampling within the domain of a wavelet transform , a multiscale block-CS algorithm with smoothed projected Land-weber reconstruction algorithm is provided .Block-based CS sampling is applied independently within each subband of each decomposition level of a wavelet transform of a image .Experimental results reveal that the algorithm achieves a 1~3 dB gain in reconstruction PSNR over the BCS-SPL and TV as well as multiscale GPSR algorithm.%  利用压缩感知理论改善图像重构的质量是目前图像处理技术研究的焦点。通过DWT域对图像每级分解时的每个子带中应用分块采样并结合平滑投影Landweber重构算法,提出一种多尺度分块变采样率压缩感知图像重构算法。比较BCS-SPL 和TV 以及多尺度GPSR图像处理算法,文中提出的算法使重构的图像质量提高了1~3 dB。

  2. 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)

  3. 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.

  4. Characterization of Clay Minerals and Kerogen in Alberta Oil Sands Geological End Members

    Science.gov (United States)

    Zheng, Limin

    The high degree of variability of oil sands ores can be attributed to a mixture of different geological end members, i.e., estuarine sand, estuarine clay, marine sand and marine clay. This study focused on the mineralogy, especially of clay minerals, and toluene insoluble organic matter, referred to as kerogen, in different oil sands end members. Clays and kerogens will likely have a significant impact on solvent recovery from the gangue following non-aqueous bitumen extraction. The bitumen-free solids were subjected to mineralogical and geochemical analysis. Kerogens were isolated and analyzed by various characterization methods. The types of clays were identified in oriented samples by X-ray diffraction analysis. The nitrogen to carbon ratio in the isolated kerogens is found to be higher than in bitumen. There are more type III kerogens in estuarine samples and more type II kerogens in marine samples.

  5. Direct visualization of clay microfabric signatures driving organic matter preservation in fine-grained sediment

    Science.gov (United States)

    Curry, Kenneth J.; Bennett, Richard H.; Mayer, Lawrence M.; Curry, Ann; Abril, Maritza; Biesiot, Patricia M.; Hulbert, Matthew H.

    2007-04-01

    We employed direct visualization of organic matter (OM) sequestered by microfabric signatures in organo-clay systems to study mechanisms of OM protection. We studied polysaccharides, an abundant class of OM in marine sediments, associated with the nano- and microfabric of clay sediment using a novel application of transmission electron microscopy, histochemical staining (periodic acid-thiosemicarbazide-silver proteinate), and enzymatic digestion techniques. We used two experimental organo-clay sediment environments. First, laboratory-consolidated sediment with 10% chitin (w/w) added was probed for chitin before and after digestion with chitinase. Second, fecal pellets from the polychaete Heteromastus filiformis were used as a natural environment rich in clay and polysaccharides. Sections of this material were probed with silver proteinate for polysaccharides before and after digestion with a mixture of enzymes (amylase, cellulase, chitinase, dextranase, and pectinase). In both environments, chitin or other polysaccharides were found within pores, bridging clay domains, and attached to clay surfaces in undigested samples. Digested samples showed chitin or polysaccharides more closely associated with clay surfaces and in small pores. Our results imply protective roles for both sorption to clay surfaces and encapsulation within clay microfabric signatures.

  6. 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)

  7. The effects of age-in-block on RNA-seq analysis of archival formalin-fixed paraffin-embedded (FFPE) samples

    Science.gov (United States)

    Archival samples represent a vast resource for identification of chemical and pharmaceutical targets. Previous use of formalin-fixed paraffin-embedded (FFPE) samples has been limited due to changes in RNA introduced by fixation and embedding procedures. Recent advances in RNA-seq...

  8. Mechanical properties of attapulgite clay reinforced polyurethane shape-memory nanocomposites

    NARCIS (Netherlands)

    Xu, Bin; Huang, W.M.; Pei, Y.T.; Chen, Zhenguo; Kraft, A.; Reuben, R.; Hosson, J.Th.M. De; Fu, Y.Q.

    2009-01-01

    Nanocomposites based on attapulgite clay and shape-memory polyurethane were fabricated by mechanical mixing. The mechanical properties of samples were evaluated using a micro-indentation tester. The untreated commercial attapulgite clay resulted in a significant decrease in glass transition temperat

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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)

  14. Erosion experiments in swelling clays and result evaluation

    International Nuclear Information System (INIS)

    ensure adequate buffer properties even after suffering from severe erosive mass loss. With these fixed parameters a thorough set of experiments was planned and performed at B+Tech to test the erosive properties of chosen buffer materials in different groundwater conditions. The test method was chosen to be a pinhole erosion test with two size-scales; 100 mm and 400 mm of cell length. In the pinhole test the material is compacted to a certain fixed density as a cylindrical block with a fixed diameter hole at the center axis of the block. The purpose of the pinhole tests was to test the scenario where piping channel has been formed in the buffer in the deposition hole and water flows through a single channel. Test duration depended on the test geometry, for smaller samples durations from 55-200 hours were logged, for larger samples test duration was approx. 200 hours in every case. Several issues enhancing the quality of measurements were considered and developments employed. The repeatability was ensured by carefully documenting every step of the testing process starting from the sample manufacturing to the sample dismantling. In addition, tests were performed with repetitions to yield better reliability and to gain information on the general scatter/noise in the results. Verification of the overall mass loss was performed by measuring the residual mass in the sample cells. Identical measurement run in parallel provided information on the deviation of the results and careful examination of the environmental parameters revealed 2 major problems: 1. Measurement solutions mimicking the groundwater composition are prepared with laboratory grade NaCl and CaCl2 salts. The standard clay sample drying procedure of heating the sample in 105 C oven for 24 hours is assumed to result water-free clay that contains only the residual salts that are not evaporated during the drying and hence can easily deducted if the original solution salt contents are known. What is typically neglected

  15. 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...

  16. 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...

  17. Study of the mechanical properties of clay containing smectite and carbonate

    International Nuclear Information System (INIS)

    The correlation between physicochemical properties and mechanical behavior of clays is the subject of many studies. The mechanical properties of clays are particularly significant insofar as they involve several disciplines, remediation, drilling muds, civil engineering, storage of toxic and radioactive waste. The smectite used in this work is from the southern west of Tunisia, particularly from Oued Tfal near the town of Gafsa is noted OT. Work included action on the characterization, physicochemical and mechanical properties of the raw clay treated with hydrochloric acid and purified. This work aims at studying the influence of pure clay fraction, including compensating cations on the hydromechanical properties of clay. The thermal study sample gives a percentage of 32.5% of carbonate in the raw clay. The elimination of carbonates by acid attack controlled the following results: If treatment by 0.5M represents a departure total of carbonates, there are probably altered layers of the clay fraction. To eliminate the excess of carbonate (6.03%), the sample was treated by 0.4 M HCl without deterioration of the structure of the silicate fraction. The hydromechanical study of three samples of raw clay (OT) purified (OTNa) and treated by (0.4M) hydrochloric acid put it clearly the relationship between the cation exchange capacity the percentage of carbonate and the swelling pressure.

  18. 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.

  19. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.W.W.; Chen, Z.K.; Coo, J.L. [Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Chen, R., E-mail: chenrui1005@hotmail.com [Shenzhen Key Laboratory of Urban and Civil Engineering for Disaster Prevention and Mitigation, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055 (China); Zhou, C. [Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2015-10-15

    Highlights: • Explore feasibility of unsaturated clay as a gas barrier in landfill cover. • Gas breakthrough pressure increases with clay thickness and degree of saturation. • Gas emission rate decreases with clay thickness and degree of saturation. • A 0.6 m-thick clay layer may be sufficient to meet gas emission rate limit. - Abstract: Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas–water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different

  20. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover

    International Nuclear Information System (INIS)

    Highlights: • Explore feasibility of unsaturated clay as a gas barrier in landfill cover. • Gas breakthrough pressure increases with clay thickness and degree of saturation. • Gas emission rate decreases with clay thickness and degree of saturation. • A 0.6 m-thick clay layer may be sufficient to meet gas emission rate limit. - Abstract: Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas–water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different

  1. 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

  2. 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

  3. 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)...

  4. 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

  5. Geological and technological characteristics of the Ball Clay of the Sao Paulo state

    International Nuclear Information System (INIS)

    This paper shows preliminary geological and technological results of studies about ball clay in Sao Paulo State. The works had been carried out by the Institute of Research and technology (IPT) and sponsored by Prominerio, during 88. Ball clay is a special clay utilised in the whiteware industry, mainly in the body preparation of sanitaryware products. This raw material come from two sites in Brazil: Sao Simao and Oeiras. Samples from these two deposits had been studied and classified acording to their adequately in the ceramic process. On the other hand, more than 100 samples from several geological sites of the Sao Paulo State were studied in laboratories. Acording to preliminary tests some of them revealed similar characteristics as brazilian ball clays. These clays were characterized by granulometry analysis, X-ray diffraction and chemical analysis. (author)

  6. 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.)

  7. 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.

  8. 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)

  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. 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.

  11. A review of WIPP [Waste Isolation Pilot Plant] repository clays and their relationship to clays of adjacent strata

    International Nuclear Information System (INIS)

    The Salado Formation is a thick evaporite sequence located in the Permian Delaware Basin of southeastern New Mexico. This study focuses on the intense diagenetic alteration that has affected the small amounts of clay, feldspar, and quartz washed into the basin during salt deposition. These changes are of more than academic interest since this formation also houses the WIPP (Waste Isolation Pilot Plant). Site characterization concerns warrant compiling a detailed data base describing the clays in and around the facility horizon. An extensive sampling effort was undertaken to address these programmatic issues as well as to provide additional insight regarding diagenetic mechanisms in the Salado. Seventy-five samples were collected from argillaceous partings in halite at the stratigraphic level of the Waste Isolation Pilot Plant (WIPP). These were compared with twenty-eight samples from cores of the Vaca Triste member of the Salado, a thin clastic unit at the top of the McNutt potash zone, and with a clay-rich sample from the lower contact of the Culebra Dolomite (in the overlying Rustler Formation). These settings were compared to assess the influence of differences in brine chemistry (i.e., halite and potash facies, normal to hypersaline marine conditions) and sediment composition (clays, sandy silt, dolomitized limestone) on diagenetic processes. 44 refs., 11 figs., 5 tabs

  12. 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)

  13. Thermo-hydro-mechanical characterization of the Spanish reference clay material for engineered barrier for granite and clay HLW repository: laboratory and small mock up testing

    International Nuclear Information System (INIS)

    This report refers to the work carried out by Technic Geologic Division of CIEMAT (CIEMAT.DT.TG) coordinated by SCK/CEN (Belgium), participating besides UPC-DIT and University of Wales on the framework of CEC Contract F12W-CT91-0102 (DOEO). It presents the results obtained. The total results on the project will be published by CE in the EUR series. The role of CIEMAT in this project was to carry out tests in which the conditions of the clay barrier in the repository were simulated. The interaction of heat coming from the wastes and of water coming from the geological medium has been reproduced on compacted clay blocks. For the performance of tests on high density compacted clay blocks (Task 2.1) and for the cementation and chemical-mineralogical transformation studies two different cells were designed and constructed in stainless steel: a thermohydraulic cell and an alteration cell. The experiments performed in these cells have provided us with a better knowledge of the heat source, hydration system and sensors, as well as interesting data on heat and water diffusion. A revision of the experiments performed on the thermohydraulic cell was presented at the ''International Workshop on Thermomechanics of Clays and Clay Barriers'' held in Bergamo in October'93 (Villar et al. 1993)

  14. 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 ...

  15. Investigation of activated Al-pillared clay efficiency in vegetable oil purification

    Directory of Open Access Journals (Sweden)

    Lomić Gizela A.

    2004-01-01

    Full Text Available This paper represents a contribution to the applicability of natural clays and their derivates as adsorbents in the process of purification of vegetable oil. Investigation of textural properties of raw and purified clay samples reveals that during acid activation and Al-pillaring, BET and micropore surface area increases significantly. However, bleaching capacity of clay and its derivates is not determined by using sample surface area, but rather sample total pore volume. Surface area, especially micropore surface area contributes to removal of smaller molecules. This was confirmed by successful elimination of moisture and volatile materials by samples with an appropriate micropore structure. Used samples of clay and its derivates do not significantly influence acid and peroxide values of raw sunflower oil during its treatment.

  16. Blocked strainers

    International Nuclear Information System (INIS)

    Thermal insulation was the cause of the blockages that shut down five BWRs in Sweden. The main culprit was mineral wool installed when the plants started up. Physical degradation of the wool over the lifetime of the plant meant it could easily be washed out of place during a loss of coolant accident and could quickly block strainers in the emergency core cooling systems. The five BWRs are almost all back on line, equipped with larger strainers and faster backwashing capability. But the incident prompted more detailed investigation into how materials in the containment would behave during an accident. One material that caused particular concern is Caposil, a material often used to insulate the reactor vessel. Composed of natural calcium, aluminium silicates and cellulose fibres, in the event of a LOCA Caposil becomes particularly hazardous. Under high pressure, or when brought into contact with high pressure water and steam, Caposil fragments into 1 cm clumps, free fibres, and ''fines''. It is these fines which cause major problems and can block a strainer extremely quickly. The successful testing of a high performance water filter which can handle Caposil is described. (4 figures) (Author)

  17. STRUCTURING & RHEOLOGY OF MOLTEN POLYMER/CLAY NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Yuan-ze Xu; Yi-bin Xu

    2005-01-01

    The evolution and the origin of "solid-like state" in molten polymer/clay nanocomposites are studied. Using polypropylene/clay hybrid (PPCH) with sufficient maleic anhydride modified PP (PP-MA) as compatibilizer, well exfoliation yet solid-like state was achieved after annealing in molten state. Comprehensive linear viscoelasticity and non-linear rheological behaviors together with WAXD and TEM are studied on PPCH at various dispersion stages focusing on time,temperature and deformation dependencies of the "solid-like" state in molten nanocomposites. Based on these, it is revealed that the solid-structure is developed gradually along with annealing through the stages of inter-layer expansion by PP-MA,the diffusion and association of exfoliated silicate platelets, the formation of band/chain structure and, finally, a percolated clay associated network, which is responsible for the melt rigidity or solid-like state. The network will be broken down by melt frozen/crystallization and weakened at large shear or strong flow and, even more surprisingly, may be disrupted by using trace amount of silane coupling agent which may block the edge interaction of platelets. The solid-like structure causes characteristic non-linear rheological behaviors, e.g. residual stress after step shear, abnormal huge stress overshoots in step flows and, most remarkably, the negative first normal stress functions in steady shear or step flows. The rheological and structural arguments challenge the existing models of strengthened entangled polymer network by tethered polymer chains connecting clay particles or by chains in confined melts or frictional interaction among tactoids. A scheme of percolated networking of associated clay platelets, which may in band form of edge connecting exfoliated platelets, is suggested to explain previous experimental results.

  18. 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

  19. Effect of Grain Size on Selected Physico-Chemical Properties of Clay

    Directory of Open Access Journals (Sweden)

    Osumanu H. Ahmed

    2009-01-01

    Full Text Available Problem statement: Mixture of the right proportion of expanding and non-expanding clays to improve plasticity (moldability of clays used in the pot industry of Malaysia is yet to be well investigated. In addition, little is known about the choice of the right clay size to eliminate or reduce the content of undesirable compounds such as Fe2O3, Al2O3 to improve the strength of pots and roofing tiles in the country. The objective of this study was to investigate how selected physico-chemical properties of pottery clay relate to grain size of Nyalau series ((Typic Paleudults. Approach: Soil samples were refined into 25, 20 and 63 µm using size grading method. The mineralogical composition of the samples was determined using X-Ray Diffraction (XRD. The chemical composition of the samples was also determined using standard procedures. Firing was done at 800°C in a muffle furnace and the cracks of the samples recorded. Results: The clay particles with sizes 20 and 25 µm were higher in LOI and total C than that those of 63 µm regardless of grain size, the clay investigated had quartz (SiO2, illite-montmorillonite, Anatase ((TiO2 and kaolinite. Grading affected the concentrations of Fe, Al and Si as clays with particle sizes 20 and 25 µm had higher contents of the aforementioned elements compared with those of 63 µm. The clay with particles 63 µm had the best strength and this was so because the clay particles had the lowest amount of Fe, Al and Si. Conclusion: The strength of Malaysian pots could be improved upon proper grading of the clay particles.

  20. Effect of Soil Clay Content on RNA Isolation and on Detection and Quantification of Bacterial Gene Transcripts in Soil by Quantitative Reverse Transcription-PCR ▿†

    OpenAIRE

    Novinscak, A.; Filion, M.

    2011-01-01

    In this study, we evaluated the effect of soil clay content on RNA isolation and on quantitative reverse transcription-PCR (qRT-PCR) quantification of microbial gene transcripts. The amount of clay significantly altered RNA isolation yields and qRT-PCR analyses. Recommendations are made for quantifying microbial gene transcripts in soil samples varying in clay content.

  1. Frictional behavior of natural clay-rich fault gouges from ODP Leg 190, Nankai Trough, offshore Japan

    Science.gov (United States)

    McKiernan, A.; Lockner, D.; Saffer, D. M.

    2005-12-01

    The decollement at subduction interfaces localizes within sediments carried by the subducting plate, and therefore understanding the frictional behavior of these sediments provides insight into the initiation of the decollement and the nature of slip along it. Variations in frictional behavior due to the conversion of smectite to illite may affect the strength of subduction interfaces and the updip limit of the seismogenic zone. Recent work has shown that illite exhibits velocity strengthening behavior, and this study expands on previous experimental conditions by testing saturated, intact, natural samples, which are sheared parallel to the incipient plate-boundary fault. Here we present results from a mineralogically-varied suite of intact samples from Ocean Drilling Program (ODP) Leg 190, site 1174, offshore Japan. These samples range in bulk illite abundance from 21-35 wt. % and in total clay content from 45-67 wt. %. Thus our experiments provide a natural test of mineralogically-controlled frictional variability, and act as a pilot study into the role of depositional fabrics in shearing. Samples were prepared as ``wafers,'' where ODP cores were cut parallel to the depositional surface to produce thin, intact, rectangular layers, which were then sheared between Berea Sandstone and Westerly Granite driving blocks. Prepared layers of intact gouge were saturated at a controlled fluid pressure of 1 MPa, and sheared in a triaxial apparatus at normal stresses of 20, 50, 120, and 150 MPa. Initial sample thickness varied from ~1-7 mm, with maximum shear strains of ~1.5-10. Corrections were made primarily for displacement-based area change (contact area is decreased by ~40% at a maximum displacement of 10 mm) and jacket strength (linear increase in measured shear stress with displacement). Preliminary results show 1) values of μ (~0.25-0.4) similar to that previously reported for clay mixtures; 2) velocity strengthening behavior (a-b > 0) in all cases, consistent with

  2. 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

  3. 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)

  4. 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

  5. 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

  6. Performance Evaluation of Insulating Firebricks Produced from Hydrometallurgically Purified Termite Hill Clay Reinforced with Alumina

    Directory of Open Access Journals (Sweden)

    D.O. Folorunso

    2015-05-01

    Full Text Available The performance of insulating firebricks produced from hydrometallurgically purified termite hill clay admixed with varying percentages of alumina cement has been qualitatively evaluated. A large quantity of termite hill clay was mined from a location on the campus of The Federal University of Technology, Akure (FUTA, Nigeria. The bulk of clay was washed in water, the deleterious shafts decanted, the slurry dried in sun for three days and later in the oven at 90 °C for eight hours. The dried clay was then crushed and ground to a fine size of 100 µm, being the average particle size upon the sieve size analysis. Sieved clay was purified hydrometallurgically at a predetermined condition; 1.6 mol/dm3 of oxalic acid at 90 °C for 150 min. and 200 rev/min agitation. Raw and purified clays were characterized using X-ray diffraction, Scanning Electron Microscopy and Transmission Electron Microscopy. Purified clay samples containing 5 – 20 % alumina were again fired at varying temperatures of 900 °C, 1100 °C, 1300 °C and 1500 °C and tested for some important refractory properties such as permanent linear change, modulus of rupture and permeability. Sample (purified clay + 10 % alumina fired at 1500 °C that exhibited the best combination of these properties was examined under scanning electron microscope to see the effect of heat and analyzed chemically using the X-ray fluorescence machine to know the precise compositions.

  7. Characterization of karak clay from pakistan for pharmaceutical and cosmetic applications

    International Nuclear Information System (INIS)

    Full text: Clay, the most important, plentiful, and low cost naturally occurring mineral, is widely used in variety of industrial application including Pharmaceutical and cosmetic. Clay is the fine grained aluminosilicate mineral which shows the property of plasticity at appropriate water content, and becomes hard upon drying. In Pakistan there are different types of clay but till now neither of them properly identified nor characterize for specific industrial application. The objective of this work is to characterize Karak clay for pharmaceutical and cosmetic applications collected from deposit located at Shagai region, District Karak, Pakistan. The clay was characterized through Xray diffractometry (XRD), X-ray Fluorescence (XRF), trace elemental Analysis, Microbiological analysis, Cation exchange capacity (CEC), pH and swelling assays according to European, United States of America and Brazilian Pharmacopeias. Bulk Chemical analysis shows that the Aluminum oxide and silica oxide are present in large quantity which was confirmed by XRD that this sample has montmorillonite as a major while illite and kaolinite as minor clay minerals. Quartz of small quantity was also found as a non-clay mineral. After analyzing the results for sample it was concluded that the clay is a strong candidate for cosmetic purposes. (author)

  8. Characterization of karak clay from pakistan for pharmaceutical and cosmetic applications

    Energy Technology Data Exchange (ETDEWEB)

    Shah, L.A. [University of Peshawar (Pakistan); Silva-Valenzuela, M.G.; Valenzuela-Diaz, F.R.; Sayeg, I.J.; Carvalho, F.M.S. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

    2012-07-01

    Full text: Clay, the most important, plentiful, and low cost naturally occurring mineral, is widely used in variety of industrial application including Pharmaceutical and cosmetic. Clay is the fine grained aluminosilicate mineral which shows the property of plasticity at appropriate water content, and becomes hard upon drying. In Pakistan there are different types of clay but till now neither of them properly identified nor characterize for specific industrial application. The objective of this work is to characterize Karak clay for pharmaceutical and cosmetic applications collected from deposit located at Shagai region, District Karak, Pakistan. The clay was characterized through Xray diffractometry (XRD), X-ray Fluorescence (XRF), trace elemental Analysis, Microbiological analysis, Cation exchange capacity (CEC), pH and swelling assays according to European, United States of America and Brazilian Pharmacopeias. Bulk Chemical analysis shows that the Aluminum oxide and silica oxide are present in large quantity which was confirmed by XRD that this sample has montmorillonite as a major while illite and kaolinite as minor clay minerals. Quartz of small quantity was also found as a non-clay mineral. After analyzing the results for sample it was concluded that the clay is a strong candidate for cosmetic purposes. (author)

  9. Speciation of uranium in surface-modified, hydrothermally treated, (UO2)2+-exchanged smectite clays

    International Nuclear Information System (INIS)

    A successful solution to the problem of disposal and permanent storage of water soluble radioactive species must address two issues: exclusion of the radionuclides from the environment and the prevention of leaching from the storage media into the environment. Immobilization of radionuclides in clay minerals has been studied. In addition to the use of clays as potential waste forms, information about the interactions of radionuclides with clays and how such interactions affect their speciations is crucial for successful modeling of actinide-migration. X-ray absorption spectroscopy (XAS) is used to determine the uranium speciation in exchanged and surface-modified clays. The XAS data from uranyl-loaded bentonite clay are compared with those obtained after the particle surfaces have been coated with alkylsilanes. These silane films, which render the surface of the clay hydrophobic, are added in order to minimize the ability of external water to exchange with the water in the clay interlayer, thereby decreasing the release rate of the exchanged-uranium species. Mild hydrothermal conditions are used in an effort to mimic potential geologic conditions that may occur during long-term radioactive waste storage. The XAS spectra indicate that the uranyl monomer species remain unchanged in most samples, except in those samples that were both coated with an alkylsilane and hydrothermally treated. When the clay was coated with an organic film, formed by the acidic deposition of octadecyltrimethoxysilane, hydrothermal treatment results in the formation of aggregated uranium species in which the uranium is reduced from UVI to UIV

  10. 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.

  11. 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)

  12. 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)

  13. Thermal Performance of Hollow Clay Brick with Low Emissivity Treatment in Surface Enclosures

    Directory of Open Access Journals (Sweden)

    Roberto Fioretti

    2014-10-01

    Full Text Available External walls made with hollow clay brick or block are widely used for their thermal, acoustic and structural properties. However, the performance of the bricks frequently does not conform with the minimum legal requirements or the values required for high efficiency buildings, and for this reason, they need to be integrated with layers of thermal insulation. In this paper, the thermal behavior of hollow clay block with low emissivity treatment on the internal cavity surfaces has been investigated. The purpose of this application is to obtain a reduction in the thermal conductivity of the block by lowering the radiative heat exchange in the enclosures. The aims of this paper are to indicate a methodology for evaluating the thermal performance of the brick and to provide information about the benefits that should be obtained. Theoretical evaluations are carried out on several bricks (12 geometries simulated with two different thermal conductivities of the clay, using a finite elements model. The heat exchange procedure is implemented in accordance with the standard, so as to obtain standardized values of the thermal characteristics of the block. Several values of emissivity are hypothesized, related to different kinds of coating. Finally, the values of the thermal transmittance of walls built with the evaluated blocks have been calculated and compared. The results show how coating the internal surface of the cavity provides a reduction in the thermal conductivity of the block, of between 26% and 45%, for a surface emissivity of 0.1.

  14. In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay.

    Science.gov (United States)

    Li, Baoshan; Liu, Zhenxing; Han, Chunying; Ma, Wei; Zhao, Songjie

    2012-07-01

    Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed by in situ method has been effectively introduced into the framework of mesoporous silica pillared clay and its Keggin structure remained perfectly after formation of the materials. In addition, samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. HPW in the incorporated samples was better dispersed into the silica pillared clay than in the impregnated samples. The results of catalytic tests indicated that the encapsulated materials demonstrated better catalytic performance than the impregnated samples in oxidative desulfurization (ODS) of dibenzothiophene (DBT). PMID:22513168

  15. Physico-chemical characterization of clays at Kalpakkam nuclear plant site towards assessment of radioactive waste disposal

    International Nuclear Information System (INIS)

    Highlights: → Colloidal clay particles in groundwater have the potential to transport radionuclides in the ground environment. → Transport of radionuclides through groundwater depends on the nature of the clay colloids and its zeta potential. → The low CEC value of the kaolinite clay colloids ensures reduced potential for transport of radionuclides. → The low cation exchange capacity of the clay mineral in the study area emphasizes the requirement of suitable backfill materials around disposal facilities. - Abstract: In order to evaluate the safety of a radioactive waste repository in a geological formation, it is necessary to study the prevailing sub surface geology surrounding the disposal facility. The Kalpakkam subsurface was found to comprise of charnockite/hypersthene granite which is overlain by clay, sandy clay and sand. Clays can act as a barrier for groundwater flow and attenuate radionuclide migration. Accordingly, in the present study, clay samples were collected at chosen depths in the subsurface within the study area at Kalpakkam and colloidal clay fractions were separated. The clay colloids after separation were characterized for their size, shape, morphology, elemental composition and zeta potential. Photon correlation spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction technique and zetasizer were used to characterize the colloidal particles. The detailed characterization and analysis has revealed that the major clay mineral present in the subsurface at Kalpakkam is kaolinite. Minor quantities of smectite and illite were also identified in some clay samples. It was observed that the clays present in the study area are having low cation exchange capacity for radionuclides and emphasizes the requirement of proper backfill materials around disposal facilities for retardation of radionuclide migration. The occurrence of clay minerals at depths within the aquifer thickness warrants analysis of

  16. Physico-chemical characterization of clays at Kalpakkam nuclear plant site towards assessment of radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Deepthi Rani, R. [Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam 603 102, Tamil Nadu (India); Sasidhar, P., E-mail: sasidhar@igcar.gov.in [Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam 603 102, Tamil Nadu (India)

    2011-06-15

    Highlights: > Colloidal clay particles in groundwater have the potential to transport radionuclides in the ground environment. > Transport of radionuclides through groundwater depends on the nature of the clay colloids and its zeta potential. > The low CEC value of the kaolinite clay colloids ensures reduced potential for transport of radionuclides. > The low cation exchange capacity of the clay mineral in the study area emphasizes the requirement of suitable backfill materials around disposal facilities. - Abstract: In order to evaluate the safety of a radioactive waste repository in a geological formation, it is necessary to study the prevailing sub surface geology surrounding the disposal facility. The Kalpakkam subsurface was found to comprise of charnockite/hypersthene granite which is overlain by clay, sandy clay and sand. Clays can act as a barrier for groundwater flow and attenuate radionuclide migration. Accordingly, in the present study, clay samples were collected at chosen depths in the subsurface within the study area at Kalpakkam and colloidal clay fractions were separated. The clay colloids after separation were characterized for their size, shape, morphology, elemental composition and zeta potential. Photon correlation spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction technique and zetasizer were used to characterize the colloidal particles. The detailed characterization and analysis has revealed that the major clay mineral present in the subsurface at Kalpakkam is kaolinite. Minor quantities of smectite and illite were also identified in some clay samples. It was observed that the clays present in the study area are having low cation exchange capacity for radionuclides and emphasizes the requirement of proper backfill materials around disposal facilities for retardation of radionuclide migration. The occurrence of clay minerals at depths within the aquifer thickness warrants analysis of groundwater

  17. 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)

  18. 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

  19. 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

  20. Improved estimation of soil clay content by the fusion of remote hyperspectral and proximal geophysical sensing

    Science.gov (United States)

    Ciampalini, Andrea; André, Frédéric; Garfagnoli, Francesca; Grandjean, Gilles; Lambot, Sébastien; Chiarantini, Leandro; Moretti, Sandro

    2015-05-01

    Planning sustainable soil exploitation and land resource evaluation require up-to-date and accurate maps of soil properties. In that respect, geophysical techniques present particular interests given their non-invasiveness and their fast data acquisition capacity, which permit to characterize large areas with fine spatial and/or temporal resolutions. We investigated the relevancy of combining data from airborne hyperspectral (Hs), electromagnetic induction (EMI) and far-field ground-penetrating radar (GPR) for mapping soil properties, in particular soil clay content, at the field scale. Data from the three techniques were acquired at a test site in Mugello (Italy) characterized by relatively strong spatial variations of soil texture. Soil samples were collected for determining ground truth clay content. For the frequencies used in this study (200-650 MHz), the GPR surface reflection is mainly determined by soil dielectric permittivity, itself primarily influenced by soil moisture. In contrast, EMI is mostly sensitive to soil electrical conductivity, which integrates several soil properties including in particular soil moisture and clay content. Taking advantage of the complementary information provided by the two instruments, the GPR and EMI data were combined and correlated to local ground-truth clay content data to provide high-resolution clay content maps over the entire field area. Besides, a relationship was also observed between Hs data and clay content measurements, which permitted to produce a Hs-derived clay content map. EMI-GPR and Hs maps showed close spatial patterns and a relatively high correlation was observed between both clay content estimates, as well as between clay content estimates and ground-truth clay content measurements. Moreover, data fusion allowed constraining the EMI-GPR and Hs information and reduced the uncertainty of mapped clay content estimates. These results demonstrated great promise for integrated, digital soil mapping

  1. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

    Science.gov (United States)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

    1994-01-01

    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  2. Large Block Test Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lin, W

    2001-12-01

    This report documents the Large-Block Test (LBT) conducted at Fran Ridge near Yucca Mountain, Nevada. The LBT was a thermal test conducted on an exposed block of middle non-lithophysal Topopah Spring tuff (Tptpmn) and was designed to assist in understanding the thermal-hydrological-mechanical-chemical (THMC) processes associated with heating and then cooling a partially saturated fractured rock mass. The LBT was unique in that it was a large (3 x 3 x 4.5 m) block with top and sides exposed. Because the block was exposed at the surface, boundary conditions on five of the six sides of the block were relatively well known and controlled, making this test both easier to model and easier to monitor. This report presents a detailed description of the test as well as analyses of the data and conclusions drawn from the test. The rock block that was tested during the LBT was exposed by excavation and removal of the surrounding rock. The block was characterized and instrumented, and the sides were sealed and insulated to inhibit moisture and heat loss. Temperature on the top of the block was also controlled. The block was heated for 13 months, during which time temperature, moisture distribution, and deformation were monitored. After the test was completed and the block cooled down, a series of boreholes were drilled, and one of the heater holes was over-cored to collect samples for post-test characterization of mineralogy and mechanical properties. Section 2 provides background on the test. Section 3 lists the test objectives and describes the block site, the site configuration, and measurements made during the test. Section 3 also presents a chronology of events associated with the LBT, characterization of the block, and the pre-heat analyses of the test. Section 4 describes the fracture network contained in the block. Section 5 describes the heating/cooling system used to control the temperature in the block and presents the thermal history of the block during the test

  3. Feasibility and Performance of Full-Scale In-situ Remediation of TCE by ERD in Clay Tills

    OpenAIRE

    Broholm, Mette Martina; Damgaard, Ida; Chambon, Julie Claire Claudia; Manoli, Gabriele; Pade, Dorte Moon; Christiansen, Camilla Maymann; Binning, Philip John; Westergaard, Claus; Tsitonaki, Aikaterini; Christophersen, Mette; Kerrn-Jespersen, Henriette; Bjerg, Poul Løgstrup

    2012-01-01

    The feasibility and performance of full-scale applications of ERD in clay tills were investigated in a research project including 2 sites in Denmark, which have been undergoing remediation since 2006. At both sites organic substrates and bioaugmentation cultures have been injected in TCE-contaminated clay till. An integrated investigative approach consisting of water and clay core sample analysis, including stable isotopes and specific degraders, as well as analysis for chlorinated solvents, ...

  4. Use of wastes derived from earthquakes for the production of concrete masonry partition wall blocks.

    Science.gov (United States)

    Xiao, Zhao; Ling, Tung-Chai; Kou, Shi-Cong; Wang, Qingyuan; Poon, Chi-Sun

    2011-08-01

    Utilization of construction and demolition (C&D) wastes as recycled aggregates in the production of concrete and concrete products have attracted much attention in recent years. However, the presence of large quantities of crushed clay brick in some the C&D waste streams (e.g. waste derived collapsed masonry buildings after an earthquake) renders the recycled aggregates unsuitable for high grade use. One possibility is to make use of the low grade recycled aggregates for concrete block production. In this paper, we report the results of a comprehensive study to assess the feasibility of using crushed clay brick as coarse and fine aggregates in concrete masonry block production. The effects of the content of crushed coarse and fine clay brick aggregates (CBA) on the mechanical properties of non-structural concrete block were quantified. From the experimental test results, it was observed that incorporating the crushed clay brick aggregates had a significant influence on the properties of blocks. The hardened density and drying shrinkage of the block specimens decreased with an increase in CBA content. The use of CBA increased the water absorption of block specimens. The results suggested that the amount of crushed clay brick to be used in concrete masonry blocks should be controlled at less than 25% (coarse aggregate) and within 50-75% for fine aggregates. PMID:21570277

  5. Dramatical Impact Of Low Amounts of Swelling Clays On The Rheology Of Alpine Debris Flows

    Science.gov (United States)

    Bardou, E.; Bowen, P.; Banfill, P. G.; Boivin, P.

    2004-12-01

    Field observations show that the role and amount of swelling clays in the complex hard suspensions of alpine debris flow type were underestimated (see Boivin et al., this session). This work aims at exploring to which extent the swelling clay content influences the global rheology of a flow of rock grains from which the size spectrum extends from clays to gravel. We made a sample from calibrated materials with a grain size distribution similar to that of a viscoplastic debris flow (Bardou et al., 2003). Four replicates were made with the same grading curve. The clay content of the samples was 2% dry weight only, and different 2:1 swelling clay to 1:1 clay ratio were used. The swelling clay ratio (SCR) was calculated as the percentage of 2:1 clay in the clay fraction of the bulk samples. The 1:1 clay was (industrial) kaolinite and the 2:1 clay was a natural soil smectite. The smectite content in the bulk sample ranged from 0% to 2% dry weight, corresponding to SCR ranging from 0 to 80%. The four prepared samples were sheared in the large-size apparatus fully described in Tattersall and Banfill (1983). This apparatus is based on the measure of the torque necessary to rotate an impeller immersed in the sample. The impeller has the form of an "H" and moves in a plane according to two parallel axes. The observed behaviour were very contrasted. The sample with SCR=0 was poorly sensitive to changes in the solid concentration, in contrast to the three samples with SCR>0. Moreover, a small change in the SCR of the clay fraction induced a dramatic change of the behaviour of the mixture. For SCR=0, only little changes in the rheological parameters of the bulk samples were observed with respect to changes in the solid concentration. On the contrary the rheological parameters of the bulk samples with SCR>0, apparently followed a power law according to solid concentration. These tests carried out in the laboratory accord with observations realised on natural debris flow material

  6. Research of possibilities for use domestic kaolin clays for production of metakaolin

    Directory of Open Access Journals (Sweden)

    Mitrović Aleksandra A.

    2009-01-01

    Full Text Available Environmental concerns coming from the high energy consumption and CO2 emission associated with cement production have brought about pressures to reduce cement consumption through the use of new materials which can be applied for substitution of a part of clinker in Portland cement or a part of cement in concrete. One of the materials that satisfy requirements of sustainable development and, when added in appropriate shares, improves the properties of cement, mortars and concrete, is metakaolin (MK, a processed pozzolana. The main and widely used raw material for production of metakaolin is kaolin clay. MK is produced by calcination or 'thermal activation' of kaolin clay. The possibilities for metakaolin production are strongly related to the characteristics of the used kaolin clay. The samples of domestic kaolin clay used in this study were provided by factories Kaolin, Valjevo, and Keramika, Mladenovac. Chemical composition, mineralogical composition and thermal properties of these samples were determined. Thermal analysis (simultaneous recording of TG, DTG and DTA signals was carried out at the temperature range from 20 to 1200 °C. For both clays the results show that the loss of mass occurred in two stages. The dehydroxillation of kaolinite and formation of metakaolin occurred in the second stage. Minerals quartz and kaolinite are dominant in the clay Kaolin, Valjevo. Dehydroxillation of kaolinite and formation of metakaolin took place in the temperature range 350-800 °C. This clay does not have clearly distinct exothermic and endothermic peaks. Clay from Keramika, Mladenovac, has a higher content of the kaolinite mineral, i.e. 81.51%. The dehydroxillation of kaolinite and formation of metakaolin occurred in the temperature range 400-700 °C. This clay has two distinct endothermic peaks at 60 and 490 °C. All these results show that both clays can be used for production of metakaolin.

  7. [Species Determination and Spectral Characteristics of Swelling Clay Minerals in the Pliocene Sandstones in Xinghai, Qinghai].

    Science.gov (United States)

    Wang, Chao-wen; Chen, Jiang-jun; Fang, Qian; Yin, Ke; Hong, Han-lie

    2015-10-01

    X-ray diffraction (XRD) and Fourier infrared absorption spectroscopy (FTIR) were conducted to deepen our research on specific species and spectral characteristics of swelling clay minerals in the Pliocene sandstones in Xinghai, Qinghai province. XRD results show that swelling clay minerals are dominant clay minerals in the sandstones, which can be up to 97% in percentage. XRD patterns show 060 reflections of the samples occur both remarkably at 1.534 Å and 1.498 Å, indicating the samples contain physical mixtures of trioctahedral and dioctahedral swelling clay minerals, respectively. Further treatment of Li-300 degrees C heat and glycerol saturation shows the swelling clay minerals collapse to 9.3-9.9 Å with a partial expansion to -18 Å. This indicates the swelling clay minerals dominate montmorillonite and contain minor saponite. The montmorillonite shows no swelling after Li-300 degrees C heat and glycerol saturation because of Li+ inserting into the octahedral layers, which balances the layer charge caused by the substitution of Mg to Al. FTIR results show the samples are composed of a kind of phyllosilicate with absorbed and structural water, which is in agreement with the results of XRD. Absorbed peaks at 913, 842, 880 cm(-1), corresponding to OH associated with Al-Al, Al-Mg, and Al-Fe pairs, further indicates the minerals are dominant dioctahedron in structure. Meanwhile, absorbed peaks at 625 and 519 cm(-1), corresponding to coupled Si-O and Al-O-Si deformation, indicates parts of Si is replaced by Al in tetrahedron. The spectral characteristics of the samples are against the presence of beidellite and nontronite based on the results of XRD and FTIR, while demonstrating an,existence of montmorillonite. This study, to distinguish the specific species of swelling clay species in clay minerals, would be of great importance when using clay mineralogy to interpret provenance and climatic information. PMID:26904841

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

    International Nuclear Information System (INIS)

    transition to the stable conditions is characterized by the change of mineral composition from Montmorillonite to Illite - Chlorite. This process is accompanied with a decrease of swelling pressure to a minimum and the change of mechanical behaviour, i.e. a decrease of plasticity corresponds with increasing rock stiffness. An extensive laboratory programme has been conducted using samples from different locations and focusing on the determination of geomechanical and hydraulic properties. The measured strength and creep data clearly demonstrate the influence of burial depth and temperature on the mechanical properties. The test results delivered a comprehensive basis for the subsequent performed rock mechanical modelling. Permeability was measured in the lab on core samples with gas- and water injection tests, which demonstrated low permeabilities in the order of 10-19 to 10-21 m2 and lower. Because in repositories for radioactive or toxic waste a gas pressure may develop in the long term its potential impact on the integrity of a low permeable clay barrier has to be assessed. A long term field test (duration more than two years) has been performed in ∼ 500 m depth in a salt mine of NW-Germany where the Red Salt Clay is partly exposed. A funnel-shape oriented borehole array was installed consisting of the nearly horizontal central injection borehole (Diam. = 60 mm, sealed using a hydro-mechanical packer system) and four surrounding boreholes. Two of them were used for the detection of gas transport. In addition, in the other two boreholes a micro-seismic monitoring array was installed, each equipped with two seismic sensors. The performed multi-stage pulse tests showed very limited gas pressure decay, thus confirming the low permeability of the clay formation. In addition, although a gas-break occurred as the minimal stress criterion was transgressed, spontaneous self sealing was confirmed resulting in recovery of tightness after the gas pressure decreased. The large

  9. In-Situ interaction between cement and clay: implications for geological disposal

    International Nuclear Information System (INIS)

    The extent and the consequences of interactions between cementitious materials used in radioactive waste management and clay host rock are described. In-situ tests were performed on seven cement formulations representing materials applied in repository construction, for backfilling or for solidification of radioactive waste. Samples were exposed to realistic repository conditions of the Boom Clay Formation in the HADES underground laboratory. Chemical, physical and mineralogical changes across the cement-clay interface were identified by combined observations from Electron Probe Microanalysis, Infrared microscopy and X-Ray powder diffraction. Significant interactions in both the cement and the clay part were found in a zone extending up to several hundreds of microns. The most prominent features are (1) leaching of cement with loss of calcium and/or silicon; (2) development of a calcium-rich zone in Boom Clay close to or at contact; (3) the formation of a contact zone marked by the precipitation of a (hydrated) magnesium aluminate phase; (4) reduction in apparent porosity of initially porous/permeable materials and (5) precipitation of calcite within the cement. This elemental exchange tends to diminish pH and reduce the buffering capacity of the cement. Although hydroxide will diffuse into the clay, the development of an extensive alkaline halo in the surrounding clay is unlikely owing to the buffering capacity of the Boom Clay pore water. Copyright (2001) Material Research Society

  10. Purification and characterization of smectite clay taken from Gafsa, Tunisia: Progressive elimination of carbonates

    International Nuclear Information System (INIS)

    This work shows the results of various analysis on a representative clay sample from southern west of Tunisia, particularly from Oued Tfal near the town of Gafsa. The raw smectite contains some carbonate, quartz, chlorite, and anorthite. During the attack of the carbonate clay with a solution of hydrochloric acid, a change of the chemical composition and physical properties was observed. This change is dependent on several factors: the initial concentration of the acid, the nature of the clay, the ratio acid / clay...). Although treatment to 0.5 M represents a total removal of carbonates, there are probably altered layers of the clay fraction. The result shows that for a treatment with acid solutions of concentrations below 0.5 M there is gradual removal of carbonate without protonation of the clay layers. The characterization of the clay fraction shows that the sodium clay purified (OTNa) consists of a sodium montmorillonite smectite. The cation exchange capacity and the specific surface of OTNa measured using the method of methylene blue are equal to 82 meq/100g and 667 m2 / g respectively.

  11. Laboratory and field tests for radionuclide migration and high flow paths in clay

    International Nuclear Information System (INIS)

    Two investigations have been undertaken in this programme. Their objectives were to investigate mass transfer in clay-rich geological materials. The principal investigation was at Culham Laboratory, Oxfordshire, England where water flow within the Kimmeridge Clay was measured. The objective was to establish if silt-rich or carbonate-rich horizons within the Kimmeridge Clay act to provide fast transport paths for water flow through the succession. A subsidiary investigation was undertaken in the Underground Research Laboratory at SCK/CEN Mol, Belgium where an in-situ measurement of solute transport by diffusion was attempted. The in-situ migration experiment at the underground Research Laboratory at SCK/CEN Mol, Belgium was unsuccessful, due to problems with the engineering installation. A laboratory test of the equipment using a sample of Boom Clay yielded a value of Di of 5 x 10-11 m2s-1 and an alpha value of 0.2 using an 131I tracer. The work has therefore demonstrated the feasibility of the experiment on a laboratory scale and has identified the modifications needed to allow a successful installation of the engineered assembly. The field measurements at Culham Laboratory, Oxfordshire were completed with the flow testing of a very silty clay layer in the Kimmeridge Clay succession. Flow tests yielded a hydraulic conductivity for the very silty clay layer. Comparative tests in the clay showed its conductivity to be at least fifty times less. (author)

  12. [THE TECHNOLOGY "CELL BLOCK" IN CYTOLOGICAL PRACTICE].

    Science.gov (United States)

    Volchenko, N N; Borisova, O V; Baranova, I B

    2015-08-01

    The article presents summary information concerning application of "cell block" technology in cytological practice. The possibilities of implementation of various modern techniques (immune cytochemnical analysis. FISH, CISH, polymerase chain reaction) with application of "cell block" method are demonstrated. The original results of study of "cell block" technology made with gelatin, AgarCyto and Shadon Cyoblock set are presented. The diagnostic effectiveness of "cell block" technology and common cytological smear and also immune cytochemical analysis on samples of "cell block" technology and fluid cytology were compared. Actually application of "cell block" technology is necessary for ensuring preservation of cell elements for subsequent immune cytochemical and molecular genetic analysis. PMID:26596046

  13. Clay-mineral assemblages from some levels of K-118 drill core of Maha Sarakham evaporites, northeastern Thailand

    Science.gov (United States)

    Suwanich, Parkorn

    Clay-mineral assemblages in Middle Clastic, Middle Salt, Lower Clastic, Potash Zone, and Lower Salt, totalling 13 samples from K-118 drill core, in the Maha Sarakham Formation, Khorat Basin, northeastern Thailand were studied. The clay-size particles were separated from the water-soluble salt by water leaching. Then the samples were leached again in the EDTA solution and separated into clay-size particles by using the timing sedimentation. The EDTA-clay residues were divided and analyzed by using the XRD and XRF method. The XRD peaks show that the major-clay minerals are chlorite, illite, and mixed-layer corrensite including traces of rectorite? and paragonite? The other clay-size particles are quartz and potassium feldspar. The XRF results indicate Mg-rich values and moderate MgAl atom ratio values in those clay minerals. The variable Fe, Na, and K contents in the clay-mineral assemblages can explain the environment of deposition compared to the positions of the samples from the core. Hypothetically, mineralogy and the chemistry of the residual assemblages strongly indicate that severe alteration and Mg-enrichment of normal clay detritus occurred in the evaporite environment through brine-sediment interaction. The various Mg-enrichment varies along the various members reflecting whether sedimentation is near or far from the hypersaline brine.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Clay mineralogy of Pleistocene Lake Tecopa, Inyo County, California

    Science.gov (United States)

    Starkey, Harry C.; Blackmon, Paul D.

    1979-01-01

    Pleistocene Lake Tecopa in southeastern Inyo County, Calif., was formed when the Amargosa River was blocked at the southern end of its valley. The lake acted as a settling basin for detrital material being transported by the river. This detritus consisted of clays, quartz, feldspars, and micas which became mudstones and siltstones. These mudstones and siltstones, much eroded and dissected after the draining of the lake, extend over the entire basin and are interbedded with tuffs formed by the intermittent deposition of volcanic ashfalls in the former lake waters. These lightcolored mudstones and siltstones are tough and well indurated and break with a conchoidal fracture. The predominant clay mineral in these detrital beds is a lithiumbearing saponite, which is found not only in the lake beds but also in the area beyond the boundaries of the lake, especially in fluvial deposits in the drainage basin of the Amargosa River to the north. This saponite does not contain enough lithium to be classified as a hectorite, and we have observed no indications that this clay consists of a mixture of two phases, such as hectorite and a diluent. Some authigenic dioctahedral montmorillonite, found only in small quantities close to the tuffs, was formed by alteration of the volcanic glass of the tuffs and was then admixed with the overlying or underlying detrital clays. The only authigenic clay-type mineral found in any significant quantity is sepiolite, found near the edges of the lake basin and stratigraphically located mainly within a meter of the two uppermost tuffs. This sepiolite probably was precipitated when silica became available to the magnesium-bearing lake water through dissolution of the volcanic ash. Precipitation of sepiolite probably did not occur within the tuffs owing to the presence of alumina in solution. Zeolites were produced there and sepiolite formed outside the margins of the tuffs. Also formed by the high-pH lake waters were water-soluble minerals, which

  20. The wild tapered block bootstrap

    DEFF Research Database (Denmark)

    Hounyo, Ulrich

    In this paper, a new resampling procedure, called the wild tapered block bootstrap, is introduced as a means of calculating standard errors of estimators and constructing confidence regions for parameters based on dependent heterogeneous data. The method consists in tapering each overlapping block......-of-the-art block-based method in terms of asymptotic accuracy of variance estimation and distribution approximation. For stationary time series, the asymptotic validity, and the favorable bias properties of the new bootstrap method are shown in two important cases: smooth functions of means, and M-estimators. The...... estimator for the sample mean is shown to be robust against heteroskedasticity of the wild tapered block bootstrap. This easy to implement alternative bootstrap method works very well even for moderate sample sizes....

  1. 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...

  2. Compatibility and Impact Resistance of Biodegradable Polymer Blends Using Clays and Natural Nanotubes

    Science.gov (United States)

    Guo, Yichen; Yuan, Xue; Zuo, Xianghao; Rafailovich, Miriam

    Montmorillonite clays and Halloysite nanotubes (HNTs) were modified by surface adsorption of resorcinol di (phenyl phosphate) (RDP) oligomers. Biodegradable poly (lactic acid) (PLA) and poly (butylene adipate-co-butylene terephthalate) (PBAT) polymers were blended together with RDP coated clays and tubes. TEM images of thin sections indicated that even though both RDP coated clay nanotubes and platelets located on the interfacial region between two immiscible polymers, only the platelets, having the larger aspect ratio, were able to reduce the PBAT domain sizes. The ability of clay platelets to partially compatibilize the blend was further confirmed by the dynamic mechanical analysis (DMA) which showed that the glass transition temperatures of two polymers tend to shift closer. Izod impact testing demonstrated that the rubbery PBAT phase greatly increased the impact strength of the unfilled blend, but addition of only 5% of clay filler decrease the impact strength by nearly 50% while a small increase was observed with nanotubes at that concentration. A simple model is proposed. The clay platelets are observed to cover the interfacial area. Although they are effective at reducing the interfacial tension, they block the entanglements between two polymer phase and increase the overall brittleness. On the other hand, the HNTs are observed to lie perpendicular to the interface, which makes them less effective in reducing interfacial tension, but far more effective at retarding micro-crack propagation.

  3. PREFERENTIAL INTERCALATION BEHAVIOR OF CLAY AND ITS EFFECT ON THE THERMAL DEGRADATION IN IMMISCIBLE PP/PS BLENDS

    Institute of Scientific and Technical Information of China (English)

    Yan Zhu; Hai-yun Ma; Li-fang Tong; Zheng-ping Fang

    2008-01-01

    The typical immiscible PP/PS blend based clay nanocomposites were prepared via melt blending.The dispersion of clay was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM).Thermal stability and dynamic mechanical properties were measured by thermogravimetrical analysis (TGA) and dynamic mechanical analysis (DMA),respectively.Preferential intercalation behavior of clay in PP/PS blends was found.The dispersion of clay is significantly influenced by the polarity of PP and PS,meanwhile the location of clay can be controlled by the alternation of the polarity of PP and PS through chemical modification.The clay migrates from PS phase to PP phase with the improvement of the polarity of PP.However,when the PS is sulfonated,clay migrates back to the dispersed PS phase again.The dispersion and location of clay have profound influence on the thermal and dynamic mechanical behavior of PP/PS blends.The better the dispersion of clay in either continuous phase or disperse phase,the higher the thermal stability of the blends.Besides,samples with clay located in the continuous phase can display the best strengthening effect.

  4. 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...

  5. Estimation of bitumen and clay content in fine tailings

    International Nuclear Information System (INIS)

    Fine tailings are the components of tailings ponds and the by-product of the oil sand extraction process, consisting mostly of water with small amounts of bitumen, sand, silts and clays. Because of the large volumes of tailings, an important environmental and production process issue involves the reduction of the remaining bitumen in the tailings stream. This paper presented the results of a study that used low field nuclear magnetic resonance (NMR) in order to estimate the bitumen, clay and water content of synthetic tailings samples. NMR is a non-destructive technique that is utilized to determine compositions of oil and brine emulsions and the viscosity of heavy oil and bitumen as well as in reservoir characterization, measuring properties such as permeability, porosity, mobile and immobile fluids, and fluid saturations. The study prepared and tested numerous samples with variable water, bitumen, sand and clay concentrations in the NMR tool under ambient conditions. Two qualities of water and bitumen were used to prepare the synthetic samples. Each type of water and bitumen was analyzed as a single substance and in a mixture with the typical solids found in tailings composition. These included kaolinite, illite, sodium montmorillonite and sand. These synthetic samples were analyzed using different mixing configurations, as a function of time and in two different NMR tools. It was concluded that NMR is a potential application for on-line determination of tailings streams composition. 18 refs., 3 tabs., 17 figs

  6. Potential of Spectroradiometry to Classify Soil Clay Content

    Directory of Open Access Journals (Sweden)

    André Carnieletto Dotto

    2016-01-01

    Full Text Available ABSTRACT Diffuse reflectance spectroscopy (DRS is a fast and cheap alternative for soil clay, but needs further investigation to assess the scope of application. The purpose of the study was to develop a linear regression model to predict clay content from DRS data, to classify the soils into three textural classes, similar to those defined by a regulation of the Brazilian Ministry of Agriculture, Livestock and Food Supply. The DRS data of 412 soil samples, from the 0.0-0.5 m layer, from different locations in the state of Rio Grande do Sul, Brazil, were measured at wavelengths of 350 to 2,500 nm in the laboratory. The fitting of the linear regression model developed to predict soil clay content from the DRS data was based on a R2 value of 0.74 and 0.75, with a RMSE of 7.82 and 8.51 % for the calibration and validation sets, respectively. Soil texture classification had an overall accuracy of 79.0 % (calibration and 80.9 % (validation. The heterogeneity of soil samples affected the performance of the prediction models. Future studies should consider a previous classification of soil samples in different groups by soil type, parent material and/or sampling region.

  7. Clay pot irrigation for tomato (Lycopersicon esculentum Mill production in the north east semiarid region of Ethiopia

    Directory of Open Access Journals (Sweden)

    Kebede Woldetsadik

    2011-06-01

    Full Text Available Water shortage is one of the major constraints for production of horticultural crops in arid and semiarid regions. A field experiment was conducted to determine irrigation water and fertilizer use efficiency, growth and yield of tomato under clay pot irrigation at the experimental site of Sekota Dryland Agricultural Research Center, Lalibela, Ethiopia in 2009/10. The experiment comprised of five treatments including furrow irrigated control and clay pot irrigation with different plant population and fertilization methods, which were arranged in Randomized Complete Block Design with three replications. The highest total and marketable fruit yields were obtained from clay pot irrigation combined with application of nitrogen fertilizer with irrigation water irrespective of difference in plant population. The clay pot irrigation had seasonal water use of up to 143.71 mm, which resulted in significantly higher water use efficiency (33.62 kg m-3 as compared to the furrow irrigation, which had a seasonal water use of 485.50 mm, and a water use efficiency of 6.67 kg m-3. Application of nitrogen fertilizer with irrigation water in clay pots improved fertilizer use efficiency of tomato by up to 52% than band application with furrow or clay pot irrigation. Thus, clay pot irrigation with 33,333 plants ha-1 and nitrogen fertilizer application with irrigation water in clay pots was the best method for increasing the yield of tomato while economizing the use of water and nitrogen fertilizer in a semiarid environment.

  8. Use of clays as buffers in radioactive repositories

    International Nuclear Information System (INIS)

    For use as canister overpack, highly compacted bentonite is superior to illite and any reasonably montmorillonite-rich bentonite will do which is not too rich in sulphur. The organic content should be low and heat treatment may be required to bring this content down to an acceptable level. Heating to slightly more than 400degreeC does not affect the physical properties of neither montmorillonite, nor illite to a significant extent. Bentonite is also very suitable for use as sealing plugs in the form of highly compacted blocks. For use as backfill in tunnels and shafts, illitic clay is a candidate material which can be compacted on site to the rather high density that is required. Where a swelling capacity is needed, such as in the top part of tunnels, bentonite-based backfills are suitable and if Na saturated clay is used the bentoite fraction can be kept low. Thus, a 10 percent content of Na bentonite by weight should generally be sufficient for a well compacted mixture with respect to the required hydraulic conductivity, while a 20-30 percent content may be needed to arrive at a sufficient swelling power. The choice of a suitable clay material requires that the substance be properly characterized and tested. It is concluded that rather rigorous analyses are necessary as concerns overpacks, including mineralogical and granulometrical tests and the determination of the swelling characteristics as well as of certain chemical features. For backfills and for the current checking of all sorts of clay for use as buffer materials, the natural water content, the liquid limit and the swelling ability have to be determined, since they are the fingerprints of this type of soil. (author)

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

    Science.gov (United States)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

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

  10. 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

  11. 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.

  12. 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

  13. 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

  14. Color measurement of methylene blue dye/clay mixtures and its application using economical methods

    Science.gov (United States)

    Milosevic, Maja; Kaludjerovic, Lazar; Logar, Mihovil

    2016-04-01

    Identifying the clay mineral components of clay materials by staining tests is rapid and simple, but their applicability is restricted because of the mutual interference of the common components of clay materials and difficulties in color determination. The change of color with concentration of the dye is related to the use of colorants as a field test for identifying clay minerals and has been improved over the years to assure the accuracy of the tests (Faust G. T., 1940). The problem of measurement and standardization of color may be solved by combination of colors observed in staining tests with prepared charts of color chips available in the Munsell Book of Color, published by Munsell Color Co. Under a particular set of illumination conditions, a human eye can achieve an approximate match between the color of the dyed clay sample and that of a standard color chip, even though they do have different spectral reflectance characteristics. Experiments were carried out with diffuse reflectance spectroscopy on selected clay samples (three montmorillonite, three kaolinite and one mix-layer clay samples) saturated with different concentration of methylene blue dye solution. Dominant wavelength and purity of the color was obtained on oriented dry samples and calculated by use of the I. C. I. (x, y) - diagram in the region of 400-700 nm (reflectance spectra) without MB and after saturation with different concentrations of MB solutions. Samples were carefully photographed in the natural light environment and processed with user friendly and easily accessible applications (Adobe color CC and ColorHexa encyclopedia) available for android phones or tablets. Obtained colors were compared with Munsell standard color chips, RGB and Hexa color standards. Changes in the color of clay samples in their interaction with different concentration of the applied dye together with application of economical methods can still be used as a rapid fieldwork test. Different types of clay

  15. Mineral Composition of Clay Fraction of the Chernozems Spread out in Ovče Pole in Republic of Macedonia

    OpenAIRE

    Mile Markoski; Tatjana Mitkova; Vedran Rubinić

    2011-01-01

    The results of mineral composition of the clay fraction of the chernozems spread out in Ovče Pole are presented. The mechanical composition of the soil samples show high domination of the physical clay and clay fractions in the soil separates, what is one of the reasons for strong influence on the physical and physical-mechanical properties of the soil. The clay content is dominant in the soil separates fraction and varies from 23.60% to 56.90%, or 36.23% average. The average content of physi...

  16. 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...

  17. 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...

  18. Distribution of grain size and clay minerals in sediments from the INDEX area, central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Ambre, N.V.

    ) and showed that smectite miner- als result from different sources and processes. For the northern Indian Ocean,the clay min-erals proved to come from a detrital origin.The CIB sediments have ben influenced by terrigenous material. Earlier,Nath et al. (1989...:175–185. Aoki,S.,and T. Sudo. 1973. Mineralogical study of the core samples from the Indian Ocean,with special reference to the vertical distribution of clay minerals. Journal of Oceano-graphical Society of Japan29:87–93. Grain Size and Clay Minerals in INDEX...

  19. A remediation performance model for enhanced metabolic reductive dechlorination of chloroethenes in fractured clay till

    DEFF Research Database (Denmark)

    Manoli, Gabriele; Chambon, Julie C.; Bjerg, Poul L.;

    2012-01-01

    efficiency and timeframe. A relatively simple approach is used to link the fermentation of the electron donor soybean oil to the sequential dechlorination of trichloroethene (TCE) while considering redox conditions and the heterogeneous clay till system (clay till matrix, fractures and sand stringers). The...... model is tested on lab batch experiments and applied to describe sediment core samples from a TCE-contaminated site. Model simulations compare favorably to field observations and demonstrate that dechlorination may be limited to narrow bioactive zones in the clay matrix around fractures and sand...

  20. Clay content mapping through integration of geophysical proximal and remote sensing data

    Science.gov (United States)

    Garfagnoli, Francesca; André, Frédéric; Grandjean, Gilles; Lambot, Sébastien; Ciampalini, Andrea; Moretti, Sandro

    2013-04-01

    Soil sustainable exploitation planning and land resource evaluation require up-to-date and accurate maps of soil properties. In that respect, geophysical techniques present particular interests given their non-invasiveness and their fast data acquisition capacity, which permit to characterize large areas with fine spatial and/or temporal resolutions. We investigated the relevancy of combining data from airborne hyperspectral (Hs), electromagnetic induction (EMI) and far-field ground-penetrating radar (GPR) for mapping soil properties, in particular soil clay content, at the field scale. Data from the three techniques were acquired at a test site in Mugello (Italy) characterized by relatively strong spatial variations of soil texture. Soil samples were collected for determining actual clay contents. For the frequencies used in this study (200-2000 MHz), the GPR surface reflection is mainly determined by soil dielectric permittivity, itself primarily influenced by soil moisture. In contrast, EMI is mostly sensitive to soil electrical conductivity, which integrates several soil properties including in particular soil moisture and clay content. Taking advantage of the complementary information provided by the two instruments, the GPR and EMI data were combined and correlated to local ground-truth measurements of clay content to provide high-resolution clay content maps over the entire field area. Besides, a relationship was also observed between Hs data and clay content measurements, which permitted to produce a Hs-derived clay content map. EMI-GPR and Hs maps showed close spatial patterns and a relatively high correlation was observed between both clay content estimates, as well as between clay content estimates and ground-truth clay content measurements. Future analyses will entail more advanced Bayesian data fusion techniques for combining EMI-GPR and Hs information. These results demonstrated great promise for integrated, digital soil mapping applications.

  1. The Determination Of Scaling Factor of Clay Properties

    Directory of Open Access Journals (Sweden)

    Agus Sulaeman

    2015-05-01

    Full Text Available The observations and tests under small scale in 1-gravity condition is intended to obtain a comparative behavior of model and prototype of geotechnical case by imposing the scaling relations. Simulation to represent related structure, sub-soil and failure mechanism need to be prepared prior to do observations in this modelling. To obtain the new parameter for sub-soil simulation and inter-dependency with scaling relationship, the  ten samples with different water content of prototype clay soil were consolidated in the triaxial CU test.  After consolidation, each sample were given the arbitrarily initial mean stress po =1/3 (σ1+σ2+σ3 at the same time each corresponding void ratio were recorded. The data was plotted and numbered in the e Ln p’ axises to adopt critical state line concept. Further shear stage in triaxial CU test were done to record the stress and strain of each ten samples. Among those of ten stress strain curves there were 3 similar curves (1, 6 and 8 observed when the deviatoric stress was normalized with its po, this showed similar behavior among them. The further observation revealed that void ratio in the clay soil no. 8 (ep corresponded with void ratio of the sample no. 1 (em, stress ratio N and critical state line parameter l in the form of  em= ep+ l Ln N. To support the expression of  em= ep+ l Ln N,  The “pile loading test” case was prepared in small scale and full scale modeling, em   represented void ratio of clay in small scale and ep represented void ratio of clay at original project location. Load settlement curves were obtained from both “pile loading test” in small and full scale simulation and the result showed closely good agreement.

  2. Analysis of thermal performance in stationary periodical state of multiperforated blocks-walls

    Energy Technology Data Exchange (ETDEWEB)

    Buizza, A.; Cardinale, N.; Stefanizzi, P.

    1984-04-01

    This paper analyses the thermal behaviour of multiperforated blocks in a stationary periodical state. The authors have compared the results obtained by two different methods: the finite element method (bidimensional heat flux) and the equivalent thermal quadrupole (monodimensional heat flux). The results of two methods for multiperforated bricks and blocks of expanded clay aggregate concrete have been found in fine agreement.

  3. Modeling of the interaction between an engineered clay barrier and concrete structures in a deep storage vault

    International Nuclear Information System (INIS)

    The degradation of concrete structures in a storage vault will release an alkaline plume influencing the geochemical evolution of clay engineered barriers or plugs. The studied configuration has a representative scale and is composed of a rectangular clay barrier interfaced on one side with a cement block and on the other side with an external granitic field. A clay model including major and accessory minerals is used; cement material is supposed to be made of portlandite and CSH minerals. The clay barrier and the cement block are assumed to be initially saturated and in equilibrium with their respective interstitial water. Diffusive transport of aqueous species coupled to chemistry is simulated in a one dimension space up to 10,000 y. The feed-back of the porosity evolution on the transport properties is not taken into account. The temperature is supposed to be constant (25 C). calculations are performed with the TRIO-EF coupled transport-chemistry code. The main results deal with the evolution of the pH profile across the clay barrier, the dissolution of clay minerals and the precipitation of new solid phases in the clay such as albite, gibbsite and CSH. These simulations show that the pH excursion includes only a minor part of the clay barrier at 10,000 y and that the CSH precipitation retards the alkaline plume progression. The appearance of local accumulations of newly precipitated minerals might strongly reduce the porosity. Future developments of this work include: (1) the completion of the geochemical model by introducing other minerals in concrete (other CSH phases and sulfo-aluminates) and ion exchange sites within the clay, (2) the implementation of a precipitation/dissolution model in order to describe on a realistic way the porosity profile evolution and possible clogging phenomena

  4. 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

  5. Chemical, physical and engineering characterization of candidate backfill clays and clay admixtures for a nuclear waste repository-Part I

    International Nuclear Information System (INIS)

    Fourteen Canadian clays and clay admixtures were subjected to simulated nuclear waste repository environments. The present work is concerned with the montmorillonite-dominant materials only. The montmorillonite-dominant samples showed significant leaching on interaction with deionized water. On heating the samples at 2000C for 500 hours, montmorillonites lost intermicellar water completely and acquired cusp-like to cylindrical morphologies. The loss of water and the morphological changes in montmorillonites significantly altered the engineering characteristics. Permeability, shrinkage limits, compactability and shear strength varied in response to the dominant exchange cation in the structure of montmorillonites and the presence of other mineral components in the materials. The synthetic granite water reacted with montmorillonites and led to changes in chemical and mineralogical compositions, crystalline state and engineering properties. 12 figures, 9 tables

  6. Serbian heavy clays behavior: Application in rough ceramics

    Directory of Open Access Journals (Sweden)

    Arsenović Milica V.

    2013-01-01

    Full Text Available This study is focused on the behavior of five new deposits of heavy clays from Serbia, with the aim to evaluate their potential suitability as raw materials in rough ceramic applications. The Pfefferkorn plasticity coefficient (PC and drying susceptibility using Bigot’s curve were measured for each raw sample. Thermodilatometric analysis (TDA showed the behaviour of dry products during firing. Samples groups were fired in the range of 850°C - 1000°C. Water absorption capacity (WAC and compressive strength (CS were done in order to characterize clays after firing. Linear regression models were used to fit the results. Mathematical tools were used to determine statistical difference of major oxides content, shaping moist and compressive strength of dry laboratory products, using post-hoc Tukey`s HSD test. The chemical and mineralogical compositions of samples do not differ considerably, but their possible application does. All studied clays seem to be easily adaptable to a correct brick making process.

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

    International Nuclear Information System (INIS)

    illite and clay rocks, even though some assumptions made have to be verified. In parallel, actual 3D geometrical pore size distributions of compacted illite, and in less extent, clay rock samples, were successfully determined by combining TEM and FIB-nt analyses on materials maintained in a water-like saturation state by means of an extensive impregnation step. Based on this spatial distribution of pores, first numerical diffusion experiments were carried at the pore scale through virtual illite, enabling a better understanding of how transfer pathways are organized in the porous media. Finally, the EC CatClay project allowed a better understanding of the migration of strongly sorbing tracers through low permeability 'clay rock' formations, increasing confidence in our capacity to demonstrate that the models used to predict radionuclide migration through these rocks are scientifically sound. (authors)

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

    International Nuclear Information System (INIS)

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

  9. 基于 Block-Gibbs 抽样的无限潜 Dirichlet 分配模型的高分辨率全色遥感影像非监督分类%Unsupervised Classification of High-resolution Panchromatic Remote Sensing Image Based on Infinite Latent Dirichelt Allocation Using Block-Gibbs Sampling

    Institute of Scientific and Technical Information of China (English)

    齐银凤; 舒阳; 唐宏

    2015-01-01

    通过引入文本检索算法中的无限潜 Dirichlet 分配(infinite Latent Dirichlet Allocation,即 iLDA)模型,对遥感影像进行建模以获取地物的统计分布及其共生关系,从而实现遥感影像非监督分类。首先,将遥感影像有重叠地划分成一组大小相等的影像块(文集)。其次,以 iLDA 为基础,构建“像元”(视觉词)、“影像块”(文档)和“地物类”(主题)之间的条件概率关系,并采用 Block-Gibbs 抽样的方法来估计模型参数,从而构建基于 Block-Gibbs 抽样的 iLDA 遥感影像非监督分类模型(Block-Gibbs based iLDA,即 BG-iLDA)。最后,通过对 BG-iLDA 模型的逼近求解实现高分辨率遥感影像的非监督分类。实验结果表明,本文提出的基于 BG-iLDA 的面向对象非监督分类方法相对传统的 K-means 等算法精度更高,更能有效区分“同谱异物”的地物。%In this paper,the infinite Latent Dirichlet Allocation (iLDA)model for unsupervised classification of images is introduced.An effective unsupervised classification method using the semantic information and the symbiotic relationship from iLDA is proposed,which is used for high-resolution panchromatic images.Firstly,the image corpus is structured by overlapped segmentation of the image into sub-images.Secondly,the relationship of conditional probability among pixels (visual-words), sub-images (documents)and land objects (topics)is built.By which,the proposed method using Block-Gibbs based iLDA (BG-iLDA)is modeled.And the model parameters are estimated using the Block-Gibbs sampling.Finally,the unsupervised classification of high-resolution panchromatic images is realized by approximate solution of the BG-iLDA.Experimental results show the classification precision of the proposed method is better than the K-means method,and the effect of the different object with the same spectral characteristics is appropriately displayed by the

  10. Ultrasound guided supraclavicular block.

    LENUS (Irish Health Repository)

    Hanumanthaiah, Deepak

    2013-09-01

    Ultrasound guided regional anaesthesia is becoming increasingly popular. The supraclavicular block has been transformed by ultrasound guidance into a potentially safe superficial block. We reviewed the techniques of performing supraclavicular block with special focus on ultrasound guidance.

  11. Clay with Desiccation Cracks is an Advection Dominated Environment

    Science.gov (United States)

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

    2012-04-01

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

  12. Heating pulse tests under constant volume on natural Boom clay. Experimental results and numerical simulations

    OpenAIRE

    Lima, Analice; Romero Morales, Enrique Edgar; Vaunat, Jean; Gens Solé, Antonio; Li, X. L.

    2009-01-01

    Boom clay is a potential geological host formation for High Level Nuclear Waste in Belgium. Impact of thermal loads may play an important role on this clay formation. To this aim, heating pulse tests on intact borehole samples were carried out using an axi-symmetric heating cell. Heating tests under nearly constant volume conditions and different target temperatures (maximum 85°C) were performed under controlled hydraulic boundary conditions. Selected test result are presented and afterwards ...

  13. Thermo-hydraulic behaviour of Boom clay using a heating cell: an experimental study

    OpenAIRE

    Lima, A; Romero Morales, Enrique Edgar; Gens Solé, Antonio; Li, X. L.; Vaunat, Jean

    2012-01-01

    Boom clay formation is a potential host rock for geological disposal of high-level nuclear waste in Belgium. Heating pulse tests with controlled power supply and controlled hydraulic boundary conditions were performed under constant volume conditions to study the hydraulic impact of thermal loading on the clay. Selected test result s of intact borehole samples retrieved in horizontal direction are presented a nd discussed. The study focuses on the time evolution of temperature and po...

  14. Effects of organic matter and clay content in soil on pesticide adsorption processes

    OpenAIRE

    Rada Đurović; Jelena Gajić-Umiljendić; Tijana Đorđević

    2009-01-01

    The effect of organic matter and clay content on the adsorption of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was studied. In order to determine whether and to what degree different soil properties affect the process of determination of selected pesticides, three soils with different clay and organic matter contents were used. An optimized liquid-solid extraction procedure followed by SPME measurement was applied to analyze the selected pesticides in soil s...

  15. Hydrogen uptake and diffusion in Callovo-Oxfordian clay rock for nuclear waste disposal technology

    International Nuclear Information System (INIS)

    Highlights: • We estimated the H2(g) sorption capacity of Callovo-Oxfordian clay rock samples. • We compared H2 and N2 adsorption at different temperatures and pressures. • We estimated the H2(g) diffusion constants and mechanism at 25–300 K and 40 bar. • We worked at pressures and temperatures of interest for nuclear waste storage sites. - Abstract: The Callovo-Oxfordian clay-rich rock formation is currently considered as host rock barrier in the French geological repository facility for radioactive waste (Meuse/Haute-Marne). After the closure of the facility, hydrogen gas is expected to develop mainly from anaerobic corrosion of steel containers and other iron-containing structures. Gas pressure build-up could impact the safety of the repository. It is therefore important to acquire in-depth knowledge on the interaction between hydrogen gas and surrounding clay rock in terms of uptake ability and diffusion. Hydrogen uptake capacity was evaluated on dried clay rock samples: (i) at 20 K, to allow for hydrogen liquefaction and determine the maximal H2 uptake of the clay, and (ii) at typical pressure and temperature conditions expected to develop in the repository (up to 363 K and a hydrogen pressure of 40–60 bar). H2 absorption on the dried raw Callovo-Oxfordian start to saturate at about 30–40 bar, and the average adsorption above 40 bar is about 0.1% in weight. Quasi-elastic neutron scattering spectroscopy was used to study the diffusion mechanism of hydrogen gas in the clay rock at the microscopic scale and to determine hydrogen self-diffusion coefficients in the dry samples in the temperature range 25–300 K. Neutron data suggested that hydrogen diffuses in the dry clay rock according to Fick’s law. The findings reported in this work can help to better understand the behavior of H2 in clay rock samples

  16. 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.

  17. 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.

  18. 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

  19. Production and Characterisation of Zeolite from Ahako Clay in Kogi State, Nigeria

    Directory of Open Access Journals (Sweden)

    A. S. KOVO

    2005-06-01

    Full Text Available Zeolite, a multi-purpose material normally sourced from clay is usually for many Engineering applications. However, it is only those Zeolite that are technically well prepared that can give optimum performance during application. Obtaining a constant route for development of Zeolite in Nigeria will be a welcome development. In this study, therefore, emphasis was placed on the development of various type of Zeolite. In attempt to synthesize the Zeolite samples, 1kg of Ahako clay was beneficiated by soaking it in deionised water for four days during which the mixture was vigorously agitated. Subsequently, the mixture was sieved with a minus 60 mesh (Tyler fraction or Micro sphere of which the screened mixture was treated with 1 litre of sodium bicarbonate solution and sodium hexameta-phosphate in the ratio of 1:4 primarily for deflocculation or dispersion. The washed clay was dried in an oven set at 45oc for two days after which it was ground to fine powder.The beneficiated clay was calcined at 600°C in furnace (model 6H-85IR for two hours. Subsequently, the calcined clay was formulated into various samples by properly incorporation sodium hydroxide (Noah, Silica gel and deionised water or weight basis.The results of the XRF showed that the crude and treated clay (calcined clay contained 73.18% by weight of Sio2 and 14.5% by weight of Al2O3 and 73.20% by weight of SiO2, 7.48 by weight of Al2O3.The developed Zeolite sample should feature in their spectra (IR that are consistent with Zeolite D as obtained in sample 1 (freshly prepared, Zeolite N-A as obtained in sample II cum sample IV after aging time of 48hours and Zeolite A as obtained in sample III.

  20. Randomized Block Subgradient Methods for Convex Nonsmooth and Stochastic Optimization

    OpenAIRE

    Deng, Qi; Lan, Guanghui; Rangarajan, Anand

    2015-01-01

    Block coordinate descent methods and stochastic subgradient methods have been extensively studied in optimization and machine learning. By combining randomized block sampling with stochastic subgradient methods based on dual averaging, we present stochastic block dual averaging (SBDA)---a novel class of block subgradient methods for convex nonsmooth and stochastic optimization. SBDA requires only a block of subgradients and updates blocks of variables and hence has significantly lower iterati...

  1. A recommended procedure for the preparation of oriented clay-mineral specimens for X-ray diffraction analysis; modifications to Drever's filter-membrane peel technique

    Science.gov (United States)

    Pollastro, R.M.

    1982-01-01

    Extremely well-oriented clay mineral mounts for X-ray diffraction analysis can be prepared quickly and without introducing segregation using the filter-membrane peel technique. Mounting problems encountered with smectite-rich samples can be resolved by using minimal sample and partial air-drying of the clay film before transfer to a glass slide. Samples containing small quantities of clay can produce useful oriented specimens if Teflon masks having more restrictive areas are inserted above the membrane filter during clay deposition. War]page and thermal shock of glass slides can be controlled by using a flat, porous, ceramic plate as a holding surface during heat treatments.

  2. A multidisciplinary geophysical, geotechnical and hydrogeological investigation of quick-clay landslides in Sweden

    Science.gov (United States)

    Malehmir, A.; Krawczyk, C.; Polom, U.; Lundberg, E.; Adamczyk, A.; Malinowski, M.; Bastani, M.; Gurk, M.; Juhlin, C.; Persson, L.; Ismail, N.

    2012-04-01

    In Spring 2011, the Society of Exploration Geophysicists (SEG) through its Geoscientists Without Borders (GWB) program sponsored our project to study clay-related landslides in the Nordic countries. This project will study quick clay or rapid earth flow landslides in Sweden. Undisturbed quick clay resembles a water-saturated gel. When a mass of quick clay undergoes sufficient stress, it instantly turns into a flowing ooze, a process known as liquefaction. A small block of quick clay can liquefy from a stress change due to as little as a modest blow from a human hand, while a larger deposit is mainly vulnerable to greater stress changes, such as increased saturation by excess rainwater. Despite their abundance, our geophysical understanding of clay behavior in terms of both changes in the geometrical shape (clay formations) and changes in the physical properties are limited and require a better understanding. Quick clay landslides are not particularly constrained to steep slopes and have been known to slide even in low-to-moderate angle slopes. Geophysical investigations began in September 2011 over a known landslide scar near the Göta river in southwest Sweden, an area known to contain quick clays in parts of it. The investigations involved 2D and 3D P- and S-wave source and receiver surveys, geoelectrics, controlled-source and radio-magnetotellurics, ground gravity and magnetic surveys. These data in combination with existing geotechnical information and hydrogeological investigations should allow better insight into the mechanism(s) governing clay-related landslides in the Nordic countries and to provide high-resolution images of subsurface structures down to the bedrock. We will present preliminary results from the seismic investigations, including the 2D and 3D reflection and refraction surveys. The reflection seismic data show excellent quality and image the bedrock topography and internal layering above it down to about 100 m. Tomography results suggest the

  3. 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.

  4. 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.

  5. 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)

  6. 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...

  7. 基于半带滤波分块采样的计算任务排序算法%Computing Task Sorting Algorithm Based on Half Band Filter Sub Block Sampling

    Institute of Scientific and Technical Information of China (English)

    刘彩霞

    2015-01-01

    在计算机信息管理中,需要对计算任务按优先级或复杂度进行优化排序,实现计算效益优化.研究云计算信息系统中的计算任务优化排序算法,提高数据管理和调度的效率.传统方法采用子带合成滤波方法进行任务排序,计算开销和执行时效性方面性能不好,提出一种基于带滤波分块采样的计算任务排序算法.计算在整个计算机信息管理基站的每个站点的合计成本,根据信息匹配相关度进行资源搜索,计算任务分配时半滤波分块采样的收敛函数,得到基于半滤波分块采样的任务排序二元假设检验分配模型,实现任务优先级排序优化.仿真结果表明,采用该算法对云计算信息系统中的计算任务进行排序,能有效准确地确定计算任务的优先级,减少任务冲突,提高任务执行效率,在计算机信息管理和任务分配中具有较高应用价值.%In computer information management, the need for computing tasks according to priority or complexity of the opti-mized sorting, realize the calculation efficiency optimization. The research of cloud computing optimization algorithm of computing tasks in information system, improve the efficiency of data management and scheduling. The traditional method is using the sub-band synthesis filter method for task sequencing, the computation and the execution time of the perfor-mance is not good, put forward a sort of computing tasks with filtering algorithm based on block sampling. In the calculation of total cost of each site of the whole computer information management of base station, according to the information match-ing of resources search, calculation convergence function is assigned half filter block sampling, get the distribution sort half filter block sampling of two element hypothesis test model based on task priority scheduling optimization, implementation. The simulation results show that, the cloud computing tasks in information systems are

  8. The effect of clay incorporation on the mechanical properties of fluoroelastomer

    Energy Technology Data Exchange (ETDEWEB)

    Zen, Heloisa Augusto; Oliveira, Jonathan Pereira de; Lugao, Ademar Benevolo, E-mail: helozen@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    In this work was studied the effect of clay incorporation in the mechanical properties of fluoroelastomer (FKM). The polymer matrix that was used is a compound of the commercial terpolymer of hexafluoropropylene, vinylidene fluoride and tetrafluoroethylene, with 70% of fluor content. This type of polymer is known for its resistance to high temperature and chemical products; it has low fuel permeation which allowing be used as sealant and especially as o-ring product. The incorporation of clay was carried to avoid excessive swelling and to observe the effect in the mechanical properties, for this application was used commercial clay, Cloisite® at 1 and 2% in weigh. The incorporation of clay into the FKM was carried out in a two roll cylinder. After that, the samples with and without clay loading were submitted to gamma radiation at 20 kGy in order to observe the changes in the polymer matrix. The characterization techniques used were: mechanical testes (stress - strain), rheometric properties and degree of swelling. After radiation process, was observed an increase in the swelling degree for the irradiated samples in relation to the pristine one. The incorporated samples with 1 and 2% of clay showed an increase in the elongation which can indicate a decrease in hardness of the polymer matrix. (author)

  9. Ultrasound assisted synthesis of PMMA/clay nanocomposites: Study of oxygen permeation and flame retardant properties

    Indian Academy of Sciences (India)

    Subrata K Patra; Gyanaranjan Prusty; Sarat K Swain

    2012-02-01

    PMMA/clay nanocomposites were synthesized by ultrasound assisted emulsifier-free emulsion polymerization technique. Ultrasound waves of different power and frequencies were applied to enhance the dispersion of the clay layers with polymer matrix. The structural information of the synthesized materials was studied by X-ray diffraction (XRD) and it was revealed that the interlayer spacing increased with clay loading. The magnitude of dispersion of the clay in the polymer matrix was detected by transmission electron microscopy (TEM). The Young’s modulus, breaking stress, elongation at break, toughness, yield stress and yield strain of the nanocomposites as a function of different clay concentrations and ultrasonic power were measured. Particle diameter of the nanocomposites was measured by laser diffraction technique. Oxygen permeability of the samples was studied and it was found that the oxygen flow rate was reduced by the combined effect of clay loading and ultrasound. The flame retardant property of the nanocomposites due to clay dispersion was investigated by measurement of limiting oxygen index (LOI).

  10. MRI profiles over very wide concentration ranges: Application to swelling of a bentonite clay

    Science.gov (United States)

    Dvinskikh, S. V.; Szutkowski, K.; Furó, I.

    2009-06-01

    In MRI investigation of soils, clays, and rocks, mainly mobile water is detected, similarly to that in biological and medical samples. However, the spin relaxation properties of water in these materials and/or low water concentration may make it difficult to use standard MRI approaches. Despite these limitations, one can combine MRI techniques developed for solid and liquid states and use independent information on relaxation properties of water, interacting with the material of interest, to obtain true images of both water and material content. We present procedures for obtaining such true density maps and demonstrate their use for studying the swelling of bentonite clay by water. A constant time imaging protocol provides 1D mapping of the clay distribution in regions with clay concentration above 10 vol%. T1 relaxation time imaging is employed to monitor the clay content down to 10 -3 vol%. Data provided by those two approaches are in good agreement in the overlapping range of concentrations. Covering five orders of magnitude of clay concentration, swelling of sodium-exchanged bentonite clays from pre-compacted pellets into a gel phase is followed in detail.

  11. Use of wastes derived from earthquakes for the production of concrete masonry partition wall blocks

    International Nuclear Information System (INIS)

    Highlights: → Solved the scientific and technological challenges impeding use of waste rubble derived from earthquake, by providing an alternative solution of recycling the waste in moulded concrete block products. → Significant requirements for optimum integration on the utilization of the waste aggregates in the production of concrete blocks are investigated. → A thorough understanding of the mechanical properties of concrete blocks made with waste derived from earthquake is reported. - Abstract: Utilization of construction and demolition (C and D) wastes as recycled aggregates in the production of concrete and concrete products have attracted much attention in recent years. However, the presence of large quantities of crushed clay brick in some the C and D waste streams (e.g. waste derived collapsed masonry buildings after an earthquake) renders the recycled aggregates unsuitable for high grade use. One possibility is to make use of the low grade recycled aggregates for concrete block production. In this paper, we report the results of a comprehensive study to assess the feasibility of using crushed clay brick as coarse and fine aggregates in concrete masonry block production. The effects of the content of crushed coarse and fine clay brick aggregates (CBA) on the mechanical properties of non-structural concrete block were quantified. From the experimental test results, it was observed that incorporating the crushed clay brick aggregates had a significant influence on the properties of blocks. The hardened density and drying shrinkage of the block specimens decreased with an increase in CBA content. The use of CBA increased the water absorption of block specimens. The results suggested that the amount of crushed clay brick to be used in concrete masonry blocks should be controlled at less than 25% (coarse aggregate) and within 50-75% for fine aggregates.

  12. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover.

    Science.gov (United States)

    Ng, C W W; Chen, Z K; Coo, J L; Chen, R; Zhou, C

    2015-10-01

    Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas-water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different climate conditions. The results of experimental study and numerical simulation reveal that as the degree of saturation and thickness of clay increase, the gas breakthrough pressure increases but the gas emission rate decreases significantly. Under a gas pressure of 10 kPa (the upper bound limit of typical landfill gas pressure), a 0.6m or thicker

  13. Integrating auxiliary data and geophysical techniques for the estimation of soil clay content using CHAID algorithm

    Science.gov (United States)

    Abbaszadeh Afshar, Farideh; Ayoubi, Shamsollah; Besalatpour, Ali Asghar; Khademi, Hossein; Castrignano, Annamaria

    2016-03-01

    This study was conducted to estimate soil clay content in two depths using geophysical techniques (Ground Penetration Radar-GPR and Electromagnetic Induction-EMI) and ancillary variables (remote sensing and topographic data) in an arid region of the southeastern Iran. GPR measurements were performed throughout ten transects of 100 m length with the line spacing of 10 m, and the EMI measurements were done every 10 m on the same transect in six sites. Ten soil cores were sampled randomly in each site and soil samples were taken from the depth of 0-20 and 20-40 cm, and then the clay fraction of each of sixty soil samples was measured in the laboratory. Clay content was predicted using three different sets of properties including geophysical data, ancillary data, and a combination of both as inputs to multiple linear regressions (MLR) and decision tree-based algorithm of Chi-Squared Automatic Interaction Detection (CHAID) models. The results of the CHAID and MLR models with all combined data showed that geophysical data were the most important variables for the prediction of clay content in two depths in the study area. The proposed MLR model, using the combined data, could explain only 0.44 and 0.31% of the total variability of clay content in 0-20 and 20-40 cm depths, respectively. Also, the coefficient of determination (R2) values for the clay content prediction, using the constructed CHAID model with the combined data, was 0.82 and 0.76 in 0-20 and 20-40 cm depths, respectively. CHAID models, therefore, showed a greater potential in predicting soil clay content from geophysical and ancillary data, while traditional regression methods (i.e. the MLR models) did not perform as well. Overall, the results may encourage researchers in using georeferenced GPR and EMI data as ancillary variables and CHAID algorithm to improve the estimation of soil clay content.

  14. 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...

  15. Effect of Firing Temperature on Mechanical Properties of Fired Masonry Bricks Produced from Ipetumodu Clay

    Directory of Open Access Journals (Sweden)

    Fatai Olufemi ARAMIDE

    2012-12-01

    Full Text Available The effect of varied firing temperature on the mechanical properties of fired masonry bricks samples produced from Ipetumodu clay was investigated. The clay sample was characterized using scanning electron microscopy (SEM for the evaluation of the morphology of the sample using secondary electron imaging; and the phases/compositions of the samples using energy-dispersive X-ray (EDX analysis, X-ray diffractometer (XRD, X-ray fluorescence (XRF and atomic absorption spectroscopy (AAS. The brick samples of standard dimensions were prepared from the clay slurry. The prepared samples were sun dried for 72 hours and then fired at varied temperature (held for an hour and then allowed to cool to room temperature in the furnace. The mechanical properties (compression strength, shear strength, modulus of rupture, density and hardness of the samples were then investigated. It was observed that the mechanical properties of the fired brick samples varied with varying firing temperature due to phase changes/chemical reaction between the phases in the clay sample. It was concluded that the optimum mechanical property for brick samples within the temperature range considered is obtained at 950oC.

  16. Effects of two organomodified clays intended to food contact materials on the genomic instability and gene expression of hepatoma cells.

    Science.gov (United States)

    Maisanaba, Sara; Jordá-Beneyto, María; Cameán, Ana M; Jos, Ángeles

    2016-02-01

    Globally, food industries have made significant progress in order to increase the shelf-life of food products and have fewer economic losses. In this sense, the use of organomodified clays destined to be incorporated in polymer matrices play a novel role, leading to improved materials named nanocomposites with enhanced technological profiles. Due to the presence of these clays into the package, the safety of the consumers is a main concern. Cloisite(®)30B and Clay1 are two organomodified clays containing quaternary ammonium salts as modifiers, that can be potentially used to reinforce packaging polymers. Available toxicity data about these clays, specifically genotoxicity, is still limited and inconclusive in some aspects. Thus, the purpose of this work was to evaluate both clays ability to induce genomic instability through the cytokinesis block micronucleus cytome assay (CBMN) and for the first time, their influence in the modulation of several genes involved in genotoxicity and cell death mechanisms. Overall, no genotoxicity response was obtained in any case at the conditions tested. On the other hand, significant expression changes were observed on the genes selected. Nevertheless, further studies are highly needed to elucidate and increase the knowledge about the molecular mechanisms of clays toxicity. PMID:26721448

  17. Clay Mineralogy Investigation In The Soils Of Arid Almanaqil Ridge Gezira State Sudan Using Xrd Diffractograms

    Directory of Open Access Journals (Sweden)

    Elhag A.M.H

    2015-07-01

    Full Text Available Abstract Clay mineralogy was studied in the soils of Arid Almanaqil Ridge. The soils are classified according to the American System Keys to Soil Taxonomy 2010 in the fallowing families Fine loamy mixed isohyperthermic TypicHaplustepts unit1 sample A1 and A2 Fine mont superactive Isohyperthermic VerticHaplocambids unit2 sample A3 and Fine mont superactive isohyperthermic TypicHaploustert unit3 sample A4. Representative soil samples were collected from these units. These samples were samples A1 and A2 for unit1 sample A3 for unit 2 and sample A4 for uint3 respectively. Those samples were compared with samples from outside the study area from north of the study area sample A5 and A6 and from the alluvium of the Blue Nile sample A7 according to their lithology topographic position soil types and soil mapping units. Clay mineralogy of the samples was studied using X-ray diffractograms XRD techniques. The XRD diffractograms indicated the presence of smectite chlorite illite and kaolinite as the major clay minerals in the soil of the study area and outside of the study area. The major clay minerals in these soils Chlorite illite and kaolinite could have originated from parent material. Smectite showed an increasing trend in samples A7 outside of study area and sample A4 unit 3. The CEC of clay minerals in unit 1 and 2 were less than 50 Cmolkg which indicated that minerals with low CEC were dominant this result conformed with the XRD results that showed dominance of Chlorite illite and Kaolinite. Higher CEC values more than 50 Cmolkg of the clay were encountered in soils samples from unit3 A4 and those from outside study area Sample A7 XRD results showed that the samples were dominated by smectite. Moreover the CEC values of clay minerals were consistent with results of XRD. The X-ray mineralogy indicated that the Vertisols and Aridisols of the study area had the same origin as that of the Gezira soils.

  18. Characterization of bentonite clay from “Greda” deposit

    Directory of Open Access Journals (Sweden)

    Nadežda Stanković

    2011-06-01

    Full Text Available Based on mineralogical and technological investigations of the deposit “Greda” important characteristics of bentonite clay were determined. Representative samples of the deposit were characterized with X-ray diffraction, low-temperature nitrogen adsorption, chemical analysis, differential thermal analysis and scanning electron microscopy. It was determined that the main mineral is montmorillonite and in subordinate quantities kaolinite, quartz and pyrite. The chemical composition generally shows high silica and alumina contents in all samples and small quantities of Fe3+, Ca2+ and Mg2+ cations. Based on technological and mineralogical research, bentonite from this deposit is a high-quality raw material for use in the ceramic industry.

  19. Characterization of kaolinic clay minerals by emanation thermal analysis

    International Nuclear Information System (INIS)

    Emanation Thermal Analysis ETA), which is based on the measurement of the rate of release of radon from solid samples previously labelled with trace concentrations of inert radioactive nuclides (228Th and 224Ra), can reveal the different physico-chemical and structural phenomena that occur during the heating of kaolinite from 20 to 1,300 deg. C. The results obtained depend on the crystallinity of the kaolinite sample and demonstrate the potential of ETA as a complementary method to conventional thermo-analysis and XRD in the field of clay minerals. (authors). 17 refs., 1 fig

  20. Ultrasonic Velocities in Unconsolidated Sand/Clay Mixtures at Low Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Aracne-Ruddle, C.M.; Bonner, B.P.; Trombino, C.N.; Hardy, E.D.; Berge, P.A.; Boro, C.O.; Wildenschild, D.; Rowe, C.D.; Hart, D.J.

    1999-10-15

    Effective seismic interrogation of the near subsurface requires that measured parameters, such as compressional and shear velocities and attenuation, be related to important soil properties. Porosity, composition (clay content), fluid content and type are of particular interest. The ultrasonic (100-500 kHz) pulse transmission technique was used to collect data for highly attenuating materials appropriate to the vadose zone. Up to several meters of overburden were simulated by applying low uniaxial stress of 0 to about 0.1 MPa to the sample. The approach was to make baseline measurements for pure quartz sand, because the elastic properties are relatively well known except at the lowest pressures. Clay was added to modify the sample microstructure and ultrasonic measurements were made to characterize the effect of the admixed second phase. Samples were fabricated from Ottawa sand mixed with a swelling clay (Wyoming bentonite). The amount of clay added was 1 to 40% by mass. Compressional (P) velocities are low (228-483 m/s), comparable to the sound velocity in air. Shear (S) velocities are about half of the compressional velocity (120-298 m/s), but show different sensitivity to microstructure. Adding clay increases the shear amplitude dramatically with respect to P, and also changes the sensitivity of the velocities to load. These experiments demonstrate that P and S velocities are sensitive to the amount of clay added, even at low concentrations. Other properties of the transmitted signals including the ratio of S and P amplitudes, velocity gradient with depth, and the frequency content of transmitted pulses, provide additional information about the clay content. Direct observation of sand-clay microstructure indicated that the clay particles electrostatically cling to the sand grains but do not form a coating. Instead, in the dry mixture clay particles tended to bridge the gaps between grains, influencing how stresses were carried across grain contacts. Because of

  1. Removal of Cr(VI from Aqueous Environments Using Micelle-Clay Adsorption

    Directory of Open Access Journals (Sweden)

    Mohannad Qurie

    2013-01-01

    Full Text Available Removal of Cr(VI from aqueous solutions under different conditions was investigated using either clay (montmorillonite or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques.

  2. Clay mineral distributions in the southern Yellow Sea and their significance

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    To better understand the characteristics of the clay minerals in the southern Yellow Sea, the X-ray quantitative determinations have been carried out for the surface samples obtained from the Yellow Sea. With newly compiled clay mineral synoptic maps, the depositional processes were described for four main clay minerals (illite, chlorite, kaolinite and smectite). The analysis shows that most clay minerals are of terrigenous source with the Huanghe River acting as the major sediment supplier. Besides, the source of muddy sediments in the Yellow Sea was also discussed. As for the central Yellow Sea mud (CYSM), the sediments in its northern part mainly come from the Huanghe River, and those in the rest are of multi-origin. Very similarly, a large amount of sediments in the northern part of the southeastern Yellow Sea Mud (SEYSM) derive from the Keum River and Yeongsan River, while those in the southern part are of multi-origin.

  3. Recycling of sugarcane bagasse ash waste in the production of clay bricks.

    Science.gov (United States)

    Faria, K C P; Gurgel, R F; Holanda, J N F

    2012-06-30

    This work investigates the recycling of sugarcane bagasse ash waste as a method to provide raw material for clay brick bodies, through replacement of natural clay by up 20 wt.%. Initially, the waste sample was characterized by its chemical composition, X-ray diffraction, differential thermal analysis, particle size, morphology and pollution potential. Clay bricks pieces were prepared, and then tested, so as to determine their technological properties (e.g., linear shrinkage, water absorption, apparent density, and tensile strength). The sintered microstructure was evaluated by scanning electron microscopy (SEM). It was found that the sugarcane bagasse ash waste is mainly composed by crystalline silica particles. The test results indicate that the sugarcane bagasse ash waste could be used as a filler in clay bricks, thus enhancing the possibility of its reuse in a safe and sustainable way. PMID:22387325

  4. Magnetic properties of Jiaxian red clay sequences from northern Chinese Loess Plateau and its paleoclimatic significance

    Institute of Scientific and Technical Information of China (English)

    QIANG Xiaoke; AN Zhisheng; LI Huamei; CHANG Hong; SONG Yougui

    2005-01-01

    Detailed rock magnetism investigation of the Jiaxian red clay sequences indicated that there are common magnetic mineralogy properties in red clay and loess-paleosol sequences from the Chinese Loess Plateau as well as the marked properties of themselves, magnetic minerals mainly with magnetite, maghemite, hematite, and possibly limonite/goethite contributing to the magnetic behavior. Meanwhile, it is found that the strong paleosol in red clay sequences has a lower coercivity and higher content of ultra-fine ferrimagnetic grains than that of the weak paleosol, which is similar to loess and paleosol in upper Wucheng Loess sequences, and indicates that humid conditions and relatively strong pedogenesis play a significant role in the increase of ultra-fine magnetic minerals and transformation of the magnetic minerals. This suggests that, like Quaternary loess-paleosols, the change of characteristics of paleoclimatic conditions of the late Tertiary red clay deposits is fluctuant. In addition, the results of magnetic hysteresis properties show that the applied saturated field for samples from the Jiaxian red clay sequences is higher than that of the samples from eastern and southern Chinese Loess Plateau. It is obviously shown that there exist more hard magnetic minerals and relatively weak biochemical processes in the Jiaxian red clay sequences on northern Chinese Loess Plateau. We conclude that the paleoclimatic environment is different between northern and eastern/southern Chinese Loess Plateau, and it should be more arid in northern Chinese Loess Plateau.

  5. DIBENZO-P-DIOXINS IN THE ENVIRONMENT FROM CERAMICS AND POTTERY PRODUCED FROM BALL CLAY MINED IN THE U.S.

    Science.gov (United States)

    Processed ball clay samples used in the production of ceramics and samples of the ceramic products were collected and analyzed for the presence and concentration of the 2,3,7,8-Cl substituted polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs). The processed ball clay had...

  6. 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)

  7. 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)

  8. Biogeochemical processes in a clay formation in situ experiment: Part E - Equilibrium controls on chemistry of pore water from the Opalinus Clay, Mont Terri Underground Research Laboratory, Switzerland

    International Nuclear Information System (INIS)

    Highlights: → Equilibrium models of water-rock reactions in clay rocks are reviewed. → Analyses of pore waters of the Opalinus Clay from boreholes in the Mont Terri URL, Switzerland, are tabulated. → Results of modelling with various mineral controls are compared with the analyses. → Best agreement results with calcite, dolomite and siderite or daphnite saturation, Na-K-Ca-Mg exchange and/or kaolinite, illite, quartz and celestite saturation. → This approach allows calculation of the chemistry of pore water in clays too impermeable to yield water samples. - Abstract: The chemistry of pore water (particularly pH and ionic strength) is an important property of clay rocks being considered as host rocks for long-term storage of radioactive waste. Pore waters in clay-rich rocks generally cannot be sampled directly. Instead, their chemistry must be found using laboratory-measured properties of core samples and geochemical modelling. Many such measurements have been made on samples from the Opalinus Clay from the Mont Terri Underground Research Laboratory (URL). Several boreholes in that URL yielded water samples against which pore water models have been calibrated. Following a first synthesis report published in 2003, this paper presents the evolution of the modelling approaches developed within Mont Terri URL scientific programs through the last decade (1997-2009). Models are compared to the composition of waters sampled during dedicated borehole experiments. Reanalysis of the models, parameters and database enabled the principal shortcomings of the previous modelling efforts to be overcome. The inability to model the K concentrations correctly with the measured cation exchange properties was found to be due to the use of an inappropriate selectivity coefficient for Na-K exchange; the inability to reproduce the measured carbonate chemistry and pH of the pore waters using mineral-water reactions alone was corrected by considering clay mineral equilibria. Re

  9. Biogeochemical processes in a clay formation in situ experiment: Part E - Equilibrium controls on chemistry of pore water from the Opalinus Clay, Mont Terri Underground Research Laboratory, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, F.J., E-mail: fjpearson@gmail.com [Ground-Water Geochemistry, 5108 Trent Woods Dr., New Bern, NC 28562 (United States); Tournassat, Christophe; Gaucher, Eric C. [BRGM, B.P. 36009, 45060 Orleans Cedex 2 (France)

    2011-06-15

    Highlights: > Equilibrium models of water-rock reactions in clay rocks are reviewed. > Analyses of pore waters of the Opalinus Clay from boreholes in the Mont Terri URL, Switzerland, are tabulated. > Results of modelling with various mineral controls are compared with the analyses. > Best agreement results with calcite, dolomite and siderite or daphnite saturation, Na-K-Ca-Mg exchange and/or kaolinite, illite, quartz and celestite saturation. > This approach allows calculation of the chemistry of pore water in clays too impermeable to yield water samples. - Abstract: The chemistry of pore water (particularly pH and ionic strength) is an important property of clay rocks being considered as host rocks for long-term storage of radioactive waste. Pore waters in clay-rich rocks generally cannot be sampled directly. Instead, their chemistry must be found using laboratory-measured properties of core samples and geochemical modelling. Many such measurements have been made on samples from the Opalinus Clay from the Mont Terri Underground Research Laboratory (URL). Several boreholes in that URL yielded water samples against which pore water models have been calibrated. Following a first synthesis report published in 2003, this paper presents the evolution of the modelling approaches developed within Mont Terri URL scientific programs through the last decade (1997-2009). Models are compared to the composition of waters sampled during dedicated borehole experiments. Reanalysis of the models, parameters and database enabled the principal shortcomings of the previous modelling efforts to be overcome. The inability to model the K concentrations correctly with the measured cation exchange properties was found to be due to the use of an inappropriate selectivity coefficient for Na-K exchange; the inability to reproduce the measured carbonate chemistry and pH of the pore waters using mineral-water reactions alone was corrected by considering clay mineral equilibria. Re

  10. 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)

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

    International Nuclear Information System (INIS)

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

  12. 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.

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

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Boom Clay and Ypresian clays are investigated in the framework of the Belgian research program on the long term management of high-level and/or long-lived radioactive waste coordinated by ONDRAF/NIRAS for their potential to host a deep geological disposal repository for radioactive waste. The Boom Clay pore water geochemistry has been studied for more than two decades with the main objective to better understand the mechanisms controlling its composition. The earlier attempts to determine the pore water composition employed ex-situ batch leaching, mechanical squeezing and in-situ piezometric water sampling techniques. These studies have demonstrated that (1) the ex-situ pore water sampling techniques are prone to artifacts, so do not provide representative pore water samples, (2) in-situ pore waters from piezometers are the least affected by sampling artifacts and are therefore considered as the most representative of the real Boom Clay conditions, (3) numerous pore water samples from piezometers over large scale are needed to study the variability of the Boom Clay geochemistry, (4) to unambiguously interpret a pore water composition, it is of paramount importance to determine reliably in-situ pH and pCO2 in the same pore water sample series. To provide a sufficient amount of high quality pore water samples, a piezometric network was installed around the HADES-URF. The architecture of the network allows to evaluate the variations in the Boom Clay pore water composition in both vertical and horizontal direction. The results show that the Boom Clay pore water composition is not constant at the formation scale. The concentrations of the two most abundant species (Na and HCO3-) decrease in the Boeretang Member (top Boom Clay) in contrast to relatively stable values in the Putte Member. Small variations of these concentrations were also detected at the boundary between the Putte and Boeretang Member. An abrupt increase

  14. Evaluation of a new ICP- AES instrument for Boom Clay waters Analysis

    International Nuclear Information System (INIS)

    Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) is the work-horse for routine analyses within our analytical chemistry laboratories. A new spectrometer was purchased and installed at the end of 2005 to replace an ageing model. This new instrument is the IRIS Intrepid II XDL from Thermo Electron, which was chosen after a thorough comparison of several models offered by various manufacturers.Due to different performance characteristics, compared to the old apparatus, a complete new validation was required.We validated the method for different sample types: reactor loop waters and Boom Clay pore waters (further referred to as Boom Clay waters). This report is confined to the latter, which constitutes a significant proportion of our routine analyses, and are samples from experiments performed within the framework of geological disposal and radio-active waste projects. Boom Clay water is derived either from piezometers installed in the HADES underground research facility or from the squeezing or leaching of clay cores. Water samples from radionuclide migration experiments within Boom Clay are also analysed.Validation is the process of demonstrating that the method is fit for the intended purpose. So in this case it means quantifying the performance parameters of the method used for analysing Boom Clay waters and verifying that the values obtained are acceptable.The validation results must be as representative as possible for the matrix under investigation, which was achieved by using the remainders of previously analysed Boom Clay waters. The possibility to perform a specific validation for this particular matrix and the ability to measure such radionuclide containing samples are just two of the advantages of having an analytical service within SCK-CEN

  15. 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

  16. Interdisciplinary investigation of Boda clay-stone formation - preliminary results

    International Nuclear Information System (INIS)

    , Mecsekerc Plc, by the University of Kaposvar and colleagues of many companies. The first step of the project was to define on the basis of available information, the range of geophysical and petrophysical parameters for investigation, the analyses to be done and their temporal sequence. This was followed by the choice of core to be analyzed, being the primary requirement that the sample should be as undisturbed as possible (not too disturbed, comprehensive, stored adequately). The 598.04-608.58 m long section of Ib-4 borehole in the Gorica block, and the 480.9-481.81 m long section of the covering sandstone was chosen, to provide the completeness of investigation, and made available for the company by PURAM. The rock formation itself explored in the borehole cannot be considered as a typical BCF formation, because due to evolutionary deviations, there appear differences in cementation and compaction on the level of mineralogy, but it was matching the other sampling criteria.The chosen rock sequence is albite nest with clayey shale and clay-stone with shale, together with dolomite and clayey dolomite intercalations. After general geological characterization, dry and wet CT investigations were made on selected cores and the features of obtained data and available well-logs were compared with the results of core scanning on the whole core material and of the LIPS test, as well as with the results of mineralogical analyses. The aim of investigations made on the whole core is to appoint adequate ranges for forming rock samples on the basis of the available multi-levelled and diversified analysis results that would further the effectiveness of the assessment of later analyses. It is important that by considering the sedimentological, mineralogical, geochemical, geophysical reservoir character, sampling should be representative, according to the following aspects of investigation: - separation according to litho-facies, the basis of which is cyclicness, described on the basis of

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

    Science.gov (United States)

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

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

  18. 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

  19. 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

  20. Tc(IV) interaction with dissolved boom clay humic substances

    International Nuclear Information System (INIS)

    . These solid phases were brought in contact with humic rich (Gorleben groundwater) and humic free solutions. A next series of samples was made to mimic a more natural environment: 1) a suspension of Gorleben sand in Gorleben groundwater and 2) Boom clay sediment i n equilibrium with a synthetic groundwater, resulting in an equilibrium distribution of humic substances and Tc between the solid and the liquid phase. All the investigated samples refer to pH 8-9 conditions and showed the same EXAFS spectrum and could be all fitted by a TcO2-like phase. These results are interpreted as follows. Under reducing conditions and in the presence of a reducing solid phase (magnetite, pyrite or Gorleben sand), pertechnetate i s reduced to Tc(IV), which hydrolyses and (by a kinetically controlled process) precipitates as TcO2 (on the solid phases); however, in the presence of humic substances, TcO2 is also associated with the humic substances by way of a hydrophobic interaction mechanism between neutral inorganic Tc(IV)-colloids and organic matter colloids. (authors)

  1. Studies of locally available clays for use as radiation shielding

    International Nuclear Information System (INIS)

    Clay which is an abundant, earthy, fine-grained natural resource; mainly made of oxides of aluminium and silicon (Al2O3 and SiO2) has been investigated for its photon radiation shielding properties. Samples were collected from five (5) randomly selected clay deposits in the south-eastern coastal belt of Ghana. These deposits which are in Gbefi, Adidome and Vume in the Volta region and Kwabenya in the Greater Accra region are suspected to be of the semitic - montmorillonite group of phyllosilicates. Assin Fosu in the Central Region is strongly suspected to be a member of the Kaolinite group of phyllosilicates because of their appearance and physical characteristics. Slabs of thicknesses 1cm and 3 cm were made from the clay of each deposit by drying, grinding, sieving, moulding, drying of test pieces and then firing to a temperature of 1000±50 degrees celsius. Radiation transmission of the gammas Co-60 (1250keV) and Cs-137(662keV) and x-rays generated at tube potentials of 200kVp (164keV), 150kVp, (118keV) and 80kVp (65keV), as well as thermal conductivity and engineering property tests were performed on the slabs. For the clays studied using the five(5) energies, it has been noted that the linear attenuation coefficient increased with an increase in the density of the clay. It also increased with a decrease in the energy of the photons. Specifically, the highest photon energy, Co-60 has a linear attenuation coefficient,μ, ranging from 0.0918±0.0017cm-1 for the least dense clay to 0.1255±0.0031cm-1 for the most dense clay compared to the 0.1336cm-1 for the ordinary concrete. These values increase to 0.3774±0.0072cm-1, 0.4300±0.00169cm-1, 0.4798±0.0227cm-1, 0.4856±0.0031cm-1, and 0.5098±0.0175cm-1 for Assin Foso, Gbefi, Adidome, Kwabenya and Vume clays respectively compared to the 0.5600cm-1 for ordinary concrete for the lowest photon energy of x-rays from an 80kVp tube potential. Consequently, as density increases, the half value layer (HVL) and tenth value

  2. Diffusion and adsorption of benzene in Regina clay

    International Nuclear Information System (INIS)

    Surface or near-surface spills of hydrocarbons such as gasoline and diesel often occur in clay soils which are fractured and unsaturated. For cost-effective remediation, the extent of contamination and the distribution of the various phases should be determined before the development of remediation methods. The four volatile compounds that are commonly associated with gasoline leaking from underground fuel storage tanks are benzene, toluene, ethlybenzene and xylene. Existing diffusion test methods have been used successfully for inorganic species, but the successful application of these methods to volatile organic compounds is limited. The main difficulty with experiments using volatile organics is that there is a need for careful sample handling and sensitive analytical methods to accurately measure the aqueous concentration. Work was carried out to develop an apparatus that could be used to measure the diffusion and adsorption of volatile organics in clay. The best visual fit to the experimental data for the single reservoir test was an effective diffusion coefficient of 0.01 mL/g, and an adsorption coefficient of 0.1 mL/g. Based on diffusion cell tests, there are relatively low levels of retardation for benzene as it moves in clay soils with low organic carbon content. The implications for remediation are summarized. 28 refs., 16 figs., 5 tabs

  3. CO2 production from the Boom clay under thermal load

    International Nuclear Information System (INIS)

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

  4. 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 ...

  5. 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...

  6. 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.

  7. 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...

  8. 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...

  9. Clay-Bacteria Systems and Biofilm Production

    Science.gov (United States)

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

    2007-12-01

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

  10. 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...

  11. 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...

  12. The effect of the addition of ground olive stones on the physical and mechanical properties of clay bricks

    OpenAIRE

    Arezki, S.; Chelouah, N.; Tahakourt, A.

    2016-01-01

    This study deals with the effect of ground olive stones (GOS) on the performance of fired clay bricks. Seven different clay-GOS mixes with 0, 1, 2, 3, 4, 5 and 10 wt % of GOS respectively were used for making fired brick samples. All samples were fired at 900 °C. The technological properties of the resultant material were then determined, including shrinkage, apparent density, pore size distribution, thermal conductivity, water absorption, and compressive and flexural strength. The addition o...

  13. Incomplete block designs

    CERN Document Server

    Dey, Aloke

    2010-01-01

    This book presents a systematic, rigorous and comprehensive account of the theory and applications of incomplete block designs. All major aspects of incomplete block designs are considered by consolidating vast amounts of material from the literature - the classical incomplete block designs, like the balanced incomplete block (BIB) and partially balanced incomplete block (PBIB) designs. Other developments like efficiency-balanced designs, nested designs, robust designs, C-designs and alpha designs are also discussed, along with more recent developments in incomplete block designs for special t

  14. 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...

  15. X-ray diffraction analysis of clay stones, Muglad Sedimentary Basin, Sudan

    International Nuclear Information System (INIS)

    This study deals with the theoretical and experimental aspects of X-ray diffraction (XRD) technique. Moreover the XRD technique has been used to investigate the clay mineral types and their distribution for samples obtained from exploration wells in the Mugald Sedimentary Basin in Western Sudan. The studied samples range in depth from 1524 m to 4572 m. The XRD analysis of samples shows that they consist of kaolinite, smectite, illite, chlorite and the mixed-layer smectite/illite. Kaolinite has higher abundance (15 - 72 %) followed by illite (7 - 34 %), smectite (11 - 76 %) and the less abundance of chlorite and the mixed-layer smectite/illite. Non-clay minerals found include quartz and cristabolite. The clay mineral types and their vertical distribution reflect various controls such as environmental, burial diagenesis, source rocks and climatic influences in the Muglad Sedimentary Basin. (author). 19 refs., 11 figs., 3 tabs

  16. Main Clay Minerals in Soils of Fujian Province,China

    Institute of Scientific and Technical Information of China (English)

    WANGGUO; ZHANGWEIMING; 等

    1996-01-01

    The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evolution.Montmorillonite was found in coastal solonchak,paddy soils derived from marine deposit,lacustrine deposit and river deposit,and some lateritic red soil,red soil and yellow soil with a low weathering degree.Chlorite existed mainly in coastal solonchak and paddy soil developed from marine deposit.1.4nm intergradient mineral appeared frequently in yellow soil,red soil and lateritic red soil.The content of 1.4nm intergradient mineral increased with the decrease of weathering degree from lateritic red soil to red soil to yellow soil.Hydrous micas were more in coastal solonchak,paddy soils derived from marine deposit,lacustrine deposit and river deposit.and puple soil from purple shale than in other soils.Kaolinte was the most important clay mineral in the soils iun this province.The higher the soil weathering degree,the more the kaolinite existed.From yellow soil to red soil to lateritic red soil,kaolinite increased gradually,Kaolinite was the predominant clay mineral accompanied by few other minerals in typical lateritic red soil. Tubular halloysite was a widespread clay mineral in soils of Fujian Province with varying quantities.The soil derived from the paent rocks rich in feldspar contained more tubular halloysite.Spheroidal halloysite was found in a red soil and a paddy soil developed from olivine basalt gibbsite in the soils in this district was largely“primary gibbsite” which formed in the early weathering stage.Gibbsite decreased with the increase of weathering degree from yellow soil to red soil to lateritic red soil.Goethite also decreased in the same sequence while hematite increased.

  17. Interaction between clay minerals and hydrocarbon-utilizing indigenous microorganisms in high concentrations of heavy oil: implications for bioremediation

    International Nuclear Information System (INIS)

    This study focused on whether the presence of clay minerals (montmorillonite and kaolinite) in marine or coastal environments contaminated with high concentrations of heavy-oil spills were able to support the growth of hydrocarbon degraders to enable bioremediation. The bacterial growth experiment utilizing ∼150 g/l of heavy oil (from the Nakhodka oil spill) was conducted with 1500 mg/l of montmorillonite or kaolinite. Bacterial strain Pseudomonas aeruginosa (isolated from Atake seashore, Ishikawa Prefecture, Japan), capable of degrading heavy oil, was employed in combination with other hydrocarbon degraders inhabiting the heavy oil and seawater (collected from the Sea of Japan). The interactions among microbial cells, clay minerals and heavy oil were studied. Both clays were capable of promoting microbial growth and allowed microorganisms to proliferate (to a greater degree than in a control sample which contained no clay) in an extremely high concentration of heavy oil. Observation by transmission electron microscopy of the clay-oil-cell complexes showed that microbial cells tended to be bound primarily on the edges of the clays. X-ray diffraction analysis showed that the clay-oil and clay-oil-cell complexes involved the adsorption of microbial cells and/or heavy oil on the external surfaces of the clays. How do the interactions among clay minerals, microbial cells and heavy oil contribute to environmental factors influencing the bioremediation process? To our knowledge, there are no previous reports on the use of clay minerals in the bioremediation of the Nakhodka oil spill in combination with biofilm formation. (author)

  18. Use of organophilic clays in purification of oily wastewater; Uso de argilas organofilicas na purificacao de efluentes oleosos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.A. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Engenharia de Processos], email: adriana_anp@yahoo.com.br; Pereira, K.R de O.; Wiebeck, H.; Valenzuela-Diaz, F.R. [Universidade de Sao Paulo (EPUSP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais; Rodrigues, M. G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). CCT. Dept. de Engenharia Quimica

    2006-07-01

    Water mixed with oil is produced in great volume in industrial processes and in petroleum refineries. This mixture must be treated to return to environment or can be reused in the same process. The refine of this water is expensive and presents a difficult execution. The process of separation of oil in water used organophilic clays can be a new option. In this work, the process of preparation of organophilic clays using smectitic clay polycationic and a industrial sodium bentonite both from Paraiba State, Brazil is described. The samples were characterized by two techniques: X-ray Diffraction and Thermal Analysis. After preparation of the organophilic clays it was determined theirs swelling in organic solvents and oil adsorption capacity. The organophilic clays presented higher capacity of oil adsorption when compared to activated carbon. (author)

  19. Development of clay characterization methods for use in repository design with application to a natural Ca bentonite clay containing a redox front

    International Nuclear Information System (INIS)

    Natural smectite clays in the form of 'true' bentonites formed from volcanic ash, or resulting from in-situ weathering of rock, are suitable for a number of sealing options in repositories, both as tightening component of sand/clay backfills and as highly efficient buffer for embedment of canisters, as well as for fracture sealing. The price and quality, in terms of smectite content and type of smectite, vary considerably and an optimum choice of clay for use in repositories has to be based on quantitative quality data. This requires characterization of the clay material for which a test scheme has been worked out. It comprises determination of the granulometrical, chemical, and mineralogical compositions, as well as of certain physical properties. Recent research shows the importance of the type of smectite for the longevity of buffers in repository environment, beidellite being less favourable and saponite superior to montmorillonite, which is the most common smectite species. The test scheme hence includes means of distinguishing between various smectite minerals. The influence of accessory minerals on the chemical integrity of both the smectite and the canister material requires identification also of such minerals, for which the scheme is useful as well. The report summarizes the various test procedures and gives data from application of the scheme to samples from a natural Ca bentonite containing a redox front. This study suggests that a significant part of the iron in the clay fraction is in the form of Fe2+ in octahedral positions of the montmorillonite of unoxidized natural clay and that it is converted to Fe3+ on oxidation. Part of the iron is probably in the form of the Fe2+Fe3+ hydroxy compounds that give the unoxidized clay its bluish colour, while they can be assumed to be transformed to yellowish FeOOH forms on oxidation. (author)

  20. 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. ...

  1. 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...

  2. Characteristics and genesis of clay minerals in the northern margin of the Qaidam Basin

    Institute of Scientific and Technical Information of China (English)

    Wang Linlin; Jiang Bo; Peng Dehua; Yin Chengming; Zeng Chunlin

    2011-01-01

    In order to develop appropriate reservoir protection measures in the northern margin of the Qaidam Basin and improve its oil and gas recovery efficiency, characteristics of clay minerals from eleven clay rock samples from the northern margin of the Qaidam Basin were investigated using X-ray diffraction analysis, the Scanning Electron Microscope (SEM) and energy spectrum analysis. Clay mineral composition and distribution characteristics of the main hydrocarbon reservoirs, I.e., from the Jurassic and Paleogene-Neogene, were explored. We analyzed the main factors which affected these attributes. The results show that the major clay minerals in the northern margin are chlorite, kaolinite, illite, smectite and illite/smectite inter-stratified minerals, Illite is the most widely spread clay mineral in this area.Chlorite is mainly found in the entire Neogene and in shallow horizons of the Paleogene. Smectite is enriched in the shallow Paleogene-Neogene. There are large amounts of kaolinite and illite/smectite inter-stratified minerals in the Jurassic. The major factors affecting the different development of clay minerals in the region are properties of parent rocks, paleoclimate and paleowater media conditions,diagenesis transformation, tectonic and terrain conditions.

  3. Determination of membrane behaviour during transport of pollutants n clay barriers

    International Nuclear Information System (INIS)

    The study of the transport of contaminants in clay barriers had a extensive development in environmental geotechnics. The most studied transport processes are solutes by advection - dispersion and diffusion generated by hydraulic and chemical gradients respectively. Greater attention should be given to the chemical - osmotic flow and behavior membrane clay barriers, since in one case the water molecules move through the existence of a chemical gradient and on the other the means totally or partially inhibits the passage of solutes. The team developed to measure these processes was constructed based on items international literature and performance was verified using two types of materials KCl solution . One material is a bentonite geocomposite (Geosynthetic Clay Liner GCL ) similar to that used by other researchers. The other material is a soil barrier compacted clay (Compacted Clay Liner CCL) Fm. Corumbataí (Permian), belonging to the Paraná basin in the state of Sao Paulo, Brazil . The results show the proper performance of the equipment built . Osmotic pressure generation and membrane performance was verified for both samples. Further corroborated influence of the type of clay mineral in the osmotic pressure generated value and membrane behavior

  4. Characterization of interstitial waters and ionic exchange in the clay formations through monitoring of drilling fluids

    International Nuclear Information System (INIS)

    Clay is a very complex material which has a great variability in its mineralogical composition and allows several kind of interactions with fluid environment. The investigations of clay formations are focussed on the reactivity of clay samples and the hydraulic properties of the formations. It is however difficult to describe the geochemical properties of the whole formation. This paper presents the experiments of chemical monitoring of drilling fluids which have been carried out in two wells in Ardeche (France) by the French BRGM (Bureau de Recherches Geologiques et Minieres) with the support of ANDRA. The basic principle of the method is the use of drilling fluids to obtain informations about the clay strata included in the Triassic formations of the Southeast basin of France. Drilling fluids constitute a loop from the surface down to the geological formation and back to the surface. The fluids interact with the formation which is crushed at the bottom of the hole and their chemical composition is modified. Since the well wall rapidly collapses, the rock-drilling fluids interaction is permanently renewed and real-time information is returned to the surface by the drilling fluids. In particular, it is possible to outline Ca-Mg exchange between the clay and the drilling fluid. This study shows that the interstitial waters of clay strata are mainly sea-water derived and have been modified by diagenesis reactions. (J.S.). 15 refs., 8 figs

  5. Universal scaling of the formation factor in clays: Example from the Nankai Trough

    Science.gov (United States)

    Daigle, Hugh; Ghanbarian, Behzad; Henry, Pierre; Conin, Marianne

    2015-11-01

    Electrical conductivity is a fundamental characteristic describing how strongly a network opposes flow of electrical current. In fully water-saturated porous media the conductivity, represented by the formation factor, is mainly controlled by porosity, connectivity of the conducting phases, and the tortuosity of electrical current paths. Previous work has shown that universal scaling derived from percolation and effective medium theories accurately describes the relationship between formation factor and porosity when the percolation threshold is taken account, as well as the porosity value at which the scaling switches from percolation theory to effective medium theory. We determined the formation factor in clay-rich sediments based on cation exchange capacity measurements on samples from five scientific ocean drilling sites in the Nankai Trough. We then compared the results to predictions from universal scaling after determining the volume of clay-bound water and the percolation threshold. We found that the previously reported universal scaling relations hold in these clay-rich sediments once the corrections are made for the clay-bound water and that percolation scaling appears to be valid over the entire range of observed porosities, probably due to relatively broad pore size distributions or low pore system connectivity. Our results show that universal scaling can be applied to describe the porosity dependence of the formation factor in clay-rich sediments when appropriate corrections are made for the presence of clay-bound water.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Laurence N. Warr

    2013-01-01

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

  8. Characteristic of paramagnetic centres in burnt clay and pottery by the EPR method

    International Nuclear Information System (INIS)

    The samples of natural clay and pottery have been investigated by using electron paramagnetic resonance (EPR) method. Because of young age (100-5000 years old) of these materials and the presence of iron compounds the big doses (1-200kGy) of irradiation have been used. The authors investigated whole material without quartz extracting from acid washing. In natural clay the EPR lines were observed which disappear after clay burning and they were also not present in EPR spectrum of pottery. After clay burning at temperatures similar to these at which pottery was burnt the spectra of clay became similar to pottery spectra. These EPR spectra have also similar hyperfine structure for which the g factors are equal g1=2.0595, g2=2.0079, and g3=2.0018 for clay and g1=2.0602, g2=2.0079 and g3=2.0019 for pottery. For these lines the [AlO4]0 centre in quartz was ascribed

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

    Science.gov (United States)

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

    2013-01-01

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

  10. 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.

  11. Mineralogical characterization of Greda clays and monitoring of their phase transformations on thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chavez Panduro, E., E-mail: 04130127@unmsm.edu.pe; Bravo Cabrejos, J., E-mail: jbravoc@unmsm.edu.pe [Universidad Nacional Mayor de San Marcos, Facultad de Ciencias Fisicas (Peru)

    2010-01-15

    The mineralogical characterization of two clay samples from the Central Andean Region of Peru, denominated White Greda and Red Greda, is reported. These clays contain the clay minerals mica and illite respectively. Both clays were treated thermally in an oxidising atmosphere under controlled conditions up to 1,100 deg. C with the purpose of obtaining information about structural changes that may be useful for pottery manufacture. X-ray fluorescence was used for the elemental characterization of the samples and X-ray diffractometry was used to determine the collapse and formation of the mineral phases present in the samples caused by thermal treatment. At temperatures above 1,000 deg. C it is observed the formation of spinel in the case of White Greda and of hematite, corundum and cristobalite in the case of Red Greda. Room temperature transmission Moessbauer spectroscopy allowed the monitoring of the variation of the hyperfine parameters with the thermal treatment temperature; In the case of the evolution of the quadruple splitting of the paramagnetic Fe{sup 3+} sites with temperature, in both clays, the analyses reproduced results such as the 'camel back' curve shape, found by other workers (Wagner and Wagner, Hyperfine Interact 154:35-82, 2004; Wagner and Kyek, Hyperfine Interact 154:5-33, 2004).

  12. Postural heart block.

    OpenAIRE

    Seda, P E; McAnulty, J H; Anderson, C J

    1980-01-01

    A patient presented with orthostatic dizziness and syncope caused by postural heart block. When the patient was supine, atrioventricular conduction was normal and he was asymptomatic; when he was standing he developed second degree type II block and symptoms. The left bundle-branch block on his electrocardiogram and intracardiac electrophysiological study findings suggest that this heart block occurred distal to the His bundle. Orthostatic symptoms are usually presumed to be secondary to an i...

  13. Effect of wet grinding on structural properties of ball clay

    International Nuclear Information System (INIS)

    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature

  14. Application of chemical trated illite clay for development of ceramics products

    International Nuclear Information System (INIS)

    The chemically treatment by alkali solutions of illite clay, so-called geopolymer method, were studied to show the impact on changes of structure and crystalline phases composition of treated not dehydroxylated illite Quarternary clay, as well as ceramic properties and compressive strength of sintered respective ceramic samples. The degree of activating process were followed by FTIR-spectra, X-ray diffraction and differencial thermal analysis. The low temperature ceramic product was achieved by sintering of alkali solution (KOH or NaOH 1M, 3M, 4M and 6M) activated clay samples in temperature range from 100°C to 700°C . Sintered ceramic samples were characterized by compressive strength, total porosity, bulk density and shrinkage. It is shown that treatment of the illite Quarternary clay by KOH changes illite structure, but not destroyed. Main changes could be connected with changes of O-Al-OH grouping where O is associated with neighbour Si- layer That results into lowering of sintering temperature and development of amorphous (glassy) phase of sintered at 600–700 °C ceramic samples together with growing of total porosity. Consolidated at 600°C ceramic samples have the compressive strength ranged from 16–23 N.mm2. These values increases with growing of concentration of used alkali solution as well as with temperature for NaOH treated samples and is comparable with compressive strength for the respective ceramic products sintered at 900 °C

  15. 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.

  16. Induction of micronuclei and alteration of gene expression by an organomodified clay in HepG2 cells.

    Science.gov (United States)

    Maisanaba, Sara; Hercog, Klara; Ortuño, Natalia; Jos, Ángeles; Žegura, Bojana

    2016-07-01

    Clay2 is an organomodified montmorillonite developed by the Technological Institute of Packaging, Transport and Logistic (ITENE) in order to improve polymeric materials used in food packaging. There is not much known on Clay2 toxic potential, particularly at DNA level, therefore it is mandatory to assess its toxicity prior to its commercialization. In the present study the human hepatoma cell line (HepG2) was exposed to non-cytotoxic concentrations of Clay2 and the genomic stability was studied with the Cytokinesis block micronucleus cytome assay, by determining the formation of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs). Moreover, the expression of various genes involved in the mechanisms of its action using the real-time quantitative PCR was studied. The results obtained provide the evidence that Clay2 is potentially genotoxic as it increased the frequency of micronuclei. In addition it deregulated genes involved in the metabolism, immediate-early response/signaling, DNA damage and oxidative stress showing new valuable information on the cellular response to Clay2. Nonetheless, further studies are highly needed to elucidate the molecular mechanisms of clays toxicity. PMID:27058916

  17. Generalized Block Failure

    DEFF Research Database (Denmark)

    Jönsson, Jeppe

    2015-01-01

    shows that no readily available tests with a well-defined substantial eccentricity have been performed. This paper presents theoretical and experimental work leading towards generalized block failure capacity methods. Simple combination of normal force, shear force and moment stress distributions along......Block tearing is considered in several codes as a pure block tension or a pure block shear failure mechanism. However in many situations the load acts eccentrically and involves the transfer of a substantial moment in combination with the shear force and perhaps a normal force. A literature study...... yield lines around the block leads to simple interaction formulas similar to other interaction formulas in the codes....

  18. Catsius Clay Project. Calculation and Testing of Behaviour of Unsaturated Clay as Barrier in Radioactive Waste Repositories. Stage 2: Validation Exercises at Laboratory scale

    International Nuclear Information System (INIS)

    Stage 2 of CATSIUS CLAY Project: Validation Exercises at Laboratory Scale includes two Benchmarks, Benchmark 2.1: Oedometer Suction Controlled Tests on Samples of compacted Boom Clay and Benchmark 2.2: Small Scale Weltting-Heating Test on Compacted Bentonite. BM 2.1 had two parts: BM 2.1A (volumetric deformation upon wetting-drying cycles) and BM 2.1 B (swelling pressure test). In BM 2.1A, participants were asked to model the results of a series of five tests on samples of compacted Boom clay. In BM 2.1B, a swelling pressure test in which suction, vertical and horizontal stresses were monitored, was proposed as a blind exercise. Participants were asked to use, without further changes, the models calibrated in BM 2.1A. This exercise provides an evaluation of the capabilities of current mechanical constitutive models for unsaturated clay behaviour. It was found that, even if a calibration exercise on the basis of known experimental data is satisfactory, blind predictions of tests involving different paths may prove difficult. The test set up for BM 2.2 consisted of a stainless stell cell filled with highly expansive compacted bentonite (S2 clay from Almeria, Spain). The clay was subjected to a simultaneous central heating and a progressive water inflow through the botton plate. Temperature at various locations within the sample and the boundary radial stress were monitored throughout the test. Water content distribution was also measured at the end of the experiment. Predictions for this benchmark required the solution of field equations for flow, temperature distribution and mechanical analysis. Model parameters were derived from the extensive set of available experiments on this clay. Comparison between model predictions and measurements revealed the significance of water transport in vapour phase, the difficulties to predict boundary stresses and the general good agreement between measured and calculated temperatures. The report provides a detailed accojnt of the

  19. Catsius Clay Project. Calculation and Testing of Behaviour of Unsaturated Clay as Barrier in Radioactive Waste Repositories. Stage 2: Validation Exercises at Laboratory scale

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, E. E.; Alcoverro, J.

    1999-07-01

    Stage 2 of CATSIUS CLAY Project: Validation Exercises at Laboratory Scale includes two Benchmarks, Benchmark 2.1: Oedometer Suction Controlled Tests on Samples of compacted Boom Clay and Benchmark 2.2: Small Scale Weltting-Heating Test on Compacted Bentonite. BM 2.1 had two parts: BM 2.1A (volumetric deformation upon wetting-drying cycles) and BM 2.1 B (swelling pressure test). In BM 2.1A, participants were asked to model the results of a series of five tests on samples of compacted Boom clay. In BM 2.1B, a swelling pressure test in which suction, vertical and horizontal stresses were monitored, was proposed as a blind exercise. Participants were asked to use, without further changes, the models calibrated in BM 2.1A. This exercise provides an evaluation of the capabilities of current mechanical constitutive models for unsaturated clay behaviour. It was found that, even if a calibration exercise on the basis of known experimental data is satisfactory, blind predictions of tests involving different paths may prove difficult. The test set up for BM 2.2 consisted of a stainless stell cell filled with highly expansive compacted bentonite (S2 clay from Almeria, Spain). The clay was subjected to a simultaneous central heating and a progressive water inflow through the botton plate. Temperature at various locations within the sample and the boundary radial stress were monitored throughout the test. Water content distribution was also measured at the end of the experiment. Predictions for this benchmark required the solution of field equations for flow, temperature distribution and mechanical analysis. Model parameters were derived from the extensive set of available experiments on this clay. Comparison between model predictions and measurements revealed the significance of water transport in vapour phase, the difficulties to predict boundary stresses and the general good agreement between measured and calculated temperatures. The report provides a detailed accojnt of the

  20. Modified clay sorbents for wastewater treatment and immobilization of heavy metals in soils

    Science.gov (United States)

    Burlakovs, Juris; Klavins, Maris; Vincevica-Gaile, Zane; Stapkevica, Mara

    2014-05-01

    Soil and groundwater pollution with heavy metals is the result of both, anthropogenic and natural processes in the environment. Anthropogenic influence in great extent appears from industry, mining, treatment of metal ores and waste incineration. Contamination of soil and water can be induced by diffuse sources such as applications of agrochemicals and fertilizers in agriculture, air pollution from industry and transport, and by point sources, e.g., wastewater streams, runoff from dump sites and factories. Treatment processes used for metal removal from polluted soil and water include methodologies based on chemical precipitation, ion exchange, carbon adsorption, membrane filtration, adsorption and co-precipitation. Optimal removal of heavy metal ions from aqueous medium can be achieved by adsorption process which is considered as one of the most effective methods due to its cost-effectiveness and high efficiency. Immobilization of metals in contaminated soil also can be done with different adsorbents as the in situ technology. Use of natural and modified clay can be developed as one of the solutions in immobilization of lead, zinc, copper and other elements in polluted sites. Within the present study clay samples of different geological genesis were modified with sodium and calcium chlorides, iron oxyhydroxides and ammonium dihydrogen phosphate in variable proportions of Ca/P equimolar ratio to test and compare immobilization efficiency of metals by sorption and batch leaching tests. Sorption capacity for raw clay samples was considered as relatively lower referring to the modified species of the same clay type. In addition, clay samples were tested for powder X-ray difractometry, cation exchange, surface area properties, elemental composition, as well as scanning electron microscopy pictures of clay sample surface structures were obtained. Modified clay sorbents were tested for sorption of lead as monocontaminant and for complex contamination of heavy metals. The

  1. Activation analysis of Turkish and Canadian clays and Turkish pottery

    International Nuclear Information System (INIS)

    Activation analysis of Canadian and Turkish clays showed that Cs, Th, Sc, Hf, Ta and Co were the most useful elements to study in order to obtain a differentiation by multivariate analysis. The same elements were used to study a variety of Turkish potsherds. It was found that Roman and Byzantine pottery from Yalincak, and Phrygian pottery from Great Tumulus and Tumulus 2 were most probably made from local clay beds. Phrygian pottery from Yalincak shows a tendency to form a small sub-group. However, there are a large number of outliers. No such grouping was found with the Bronze Age pottery analyzed. About 100 mg of sample were weighed into quartz ampoules. A standard pottery was used as a reference in the measurements. Samples were irradiated for a period of 24 hours. The first activity measurements were made a week after the irradiation. The measurement lasted 4000 seconds. A 30 cm3 Ge(Li) detector was coupled to a 4096-channel pulse-height analyzer. The data were recorded on magnetic tapes which were then computer-processed to calculate the peak areas using the program GAMMANAL. Tabulated data on more than 150 samples are given. (T.G.)

  2. Aggregation and stability of anisotropic charged clay colloids in aqueous medium in the presence of salt.

    Science.gov (United States)

    Ali, Samim; Bandyopadhyay, Ranjini

    2016-01-01

    Na-montmorillonite nanoclay is a colloid of layered mineral silicate. When dispersed in water, this mineral swells on absorption of water and exfoliates into platelets with electric double layers on their surfaces. Even at low particle concentration, the aqueous dispersion can exhibit a spontaneous ergodicity breaking phase transition from a free flowing liquid to nonequilibrium, kinetically arrested and disordered states such as gels and glasses. In an earlier publication [Applied Clay Science, 2015, 114, 8592], we showed that the stability of clay gels can be enhanced by adding a salt later to the clay dispersion prepared in deionized water, rather than by adding the clay mineral to a previously mixed salt solution. Here, we directly track the collapsing interface of sedimenting clay gels using an optical method and show that adding salt after dispersing the clay mineral does indeed result in more stable gels even in very dilute dispersions. These weak gels are seen to exhibit a transient collapse after a finite delay time, a phenomenon observed previously in depletion gels. The velocity of the collapse oscillates with the age of the sample. However, the average velocity of collapse increases with sample age up to a peak value before decreasing at higher ages. With increasing salt concentration, the delay time for transient collapse decreases, while the peak value of the collapsing velocity increases. Using ultrasound attenuation spectroscopy, rheometry and cryogenic scanning electron microscopy, we confirm that morphological changes of the gel network assembly, facilitated by thermal fluctuations, lead to the observed collapse phenomenon. Since clay minerals are used extensively in polymer nanocomposites, as rheological modifiers, stabilizers and gas absorbents, we believe that the results reported in this work are extremely useful for several practical applications and also for understanding geophysical phenomena such as the formation and stability of quicksand

  3. Influence of natural mobile organic matter on europium retention on Bure clay rock

    International Nuclear Information System (INIS)

    Bure clay rock (CR) was chosen as host rock for the French high and intermediate level long lived radioactive waste repository. This choice is mostly explained by the retention ability of the Callovo-Oxfordian rock (COx). Bure clay rock contains natural organic matter (OM) that could have an influence on radionuclide retention. The aim of this work is to assess the influence of natural mobile OM on the retention of Eu on clay rock. Eu was chosen as a chemical model for trivalent actinides contained in vitrified waste. Three organic molecules were studied: suberic, sorbic and tiglic acids, small organic acids identified in COx pore water. All the experiments were carried out in an environment recreating COx water (pH=7.5; I=0.1 mol/L; PCO2 =10-2 bar).Clay rock sample characterization showed that the sample used in this work was similar to those previously extracted from the area of interest and that it was necessary to maintain pH at 7.5 to avoid altering the clay rock. The Eu-OM system study indicated that organic acids had no influence on Eu speciation in COx water. The Eu-CR system experimental study confirmed that retention implied sorption on CR (C(Eu)≤6.10-6 mol/L) and precipitation in COx water (C(Eu)≥6.10-6 mol/L). Distribution coefficient Rd (quantifying sorption) was estimated at 170 ± 30 L/g. This high value is consistent with literature values obtained on clay rocks. The ternary Eu-OM-CR system study showed a slight increase of sorption in the presence of organic matter. This synergistic effect is very satisfactory in terms of storage security: the presence of small organic acids in clay rock does not question retention properties with respect to europium and trivalent actinides. (author)

  4. 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.

  5. 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)

  6. 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.

  7. Effect of purity on adsorption capacities of a Mars-like clay mineral at different pressures

    Science.gov (United States)

    Jenkins, Traci; Mcdoniel, Bridgett; Bustin, Roberta; Allton, Judith H.

    1992-01-01

    There has been considerable interest in adsorption of carbon dioxide on Marslike clay minerals. Some estimates of the carbon dioxide reservoir capacity of the martian regolith were calculated from the amount of carbon dioxide adsorbed on the ironrich smectite nontronite under martian conditions. The adsorption capacity of pure nontronite could place upper limits on the regolith carbon dioxide reservoir, both at present martian atmospheric pressure and at the postulated higher pressures required to permit liquid water on the surface. Adsorption of carbon dioxide on a Clay Mineral Society standard containing nontronite was studied over a wide range of pressures in the absence of water. Similar experiments were conducted on the pure nontronite extracted from the natural sample. Heating curves were obtained to help characterize and determine the purity of the clay sample.

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

    International Nuclear Information System (INIS)

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

  9. Mineral Composition of Clay Fraction of the Chernozems Spread out in Ovče Pole in Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Mile Markoski

    2011-03-01

    Full Text Available The results of mineral composition of the clay fraction of the chernozems spread out in Ovče Pole are presented. The mechanical composition of the soil samples show high domination of the physical clay and clay fractions in the soil separates, what is one of the reasons for strong influence on the physical and physical-mechanical properties of the soil. The clay content is dominant in the soil separates fraction and varies from 23.60% to 56.90%, or 36.23% average. The average content of physical sand and physical clay fractions is 42.20% and 57.80% respectively. Analysis of the mineral composition of clay in its entirety showed that no one of the minerals in the analyzed chernozem samples is not in absolute domination, but there is evident higher presence of clay minerals with 2:1 lattice type (vermiculite, illite and smectites in comparison with 1:1 lattice type (kaolinite. This shows that our variety of vertical chernozems has little deteriorated physical and physical-mechanical properties compared with typical chernozems.

  10. Speciation of plutonium during sorption and diffusion in Opalinus clay

    International Nuclear Information System (INIS)

    The presented work was carried out in the framework of the BMWi-project ''Interaction and migration of actinides in natural clay rocks taking into account humic substances and clay organic matter - Interactions of neptunium and plutonium with natural clay rocks''. For the long-term safety assessments of nuclear repositories, the possible migration of the radiotoxic wastes into the environment must be considered. Due to its long half-life (T1/2 = 24000 y) 239Pu has a significant contribution to the radiotoxicity of spent nuclear fuel in a repository after long periods of storage. The redox-sensitive plutonium has a very complicated chemical behavior. In aqueous solution under environmental relevant conditions Pu can exist in oxidation states +III to +VI and it can exist in up to four oxidation states simultaneously in a solution. Clays are considered as a possible host rock formation for of high-level radioactive waste disposal. Therefore, detailed information on the mobilization and immobilization of plutonium through / into the groundwater from a repository are of special interest. In this work new insights into the interaction between Pu and natural Opalinus clay (OPA, Mont Terri, Switzerland) are obtained with regard to the disposal of heat-generating radioactive waste in a deep geological repository.rnThe focus of this work was on the determination of the speciation of Pu on the mineral surface after sorption and diffusion process by different synchrotron based techniques (μ-XRF, μ-XANES/-EXAFS, μ-XRD, and EXAFS/XANES). The interaction between Pu and OPA was studied in batch sorption and diffusion experiments in dependence of various experimental parameters (e.g. pH, Pu oxidation state). Sorption experiments showed that some experimental parameters (e.g. temperature, humic acid) have a significant impact on the sorption of Pu on OPA. Speciation studies were performed as a function of various chemical parameters on powder samples form batch experiments as

  11. 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.

  12. Bentonite clay purification for development of polymeric nan composites using a single screw extruder; Purificacao de argila bentonita para desenvolvimento de nanocomposito polimerico utilizando uma extrusora rosca simples

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    In this work, a bentonite clay rich in montmorillonite was purified and chemical treat to be used in the development of poly (methyl methacrylate) /clay nanocomposites via melting processes. After the clay treatment and purification, a masterbatch with 25% clay and 75% PMMA was produced by solution technique, using acetone as solvent. For produce samples with 2.5% clay, the masterbatch along with pure polymer were added and mixed in single screw extruder with a diameter of 16 mm and W/D 26. X-rays diffractometry (XRD) and X-rays fluorescence (XRF). Tests were performed to evaluate and characterizing the bentonite clay used in the development of this work and differential scanning calorimetry (DSC) tests were performed to evaluate changes in the thermal properties of the nanocomposites produced. (author)

  13. Transport and microstructural phenomena in bentonite clay with respect to the behavior and influence of Na, Cu and U

    International Nuclear Information System (INIS)

    MX-80 Na smectite clay, essentially consisting of montmorillonite, was investigated with respect to major transport properties and rheological behavior. Diffusion and percolation tests using sodium, copper and uranium solutions were conducted both at room temperature and at 90 deg C. In the latter case the clay samples had been hydrothermally pretreated at 90 deg C and 10 - 20 MPa pressure for 10 days. The clay dry density was 0.8 and 1.8 g/cm3 in most of the tests. The report gives the results of the diffusion, percolation and rheological studies and discusses about the transport and microstructural phenomena in bentonite. (orig.)

  14. Experimental and modeling study of flash calcination of kaolinite rich clay particles in a gas suspension calciner

    DEFF Research Database (Denmark)

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

    2015-01-01

    gas suspension calciner, with the aim to derive useful guidelines on smart calcination for obtaining products of the best pozzolanic properties. Calcination tests are performed in the calciner under six different operation conditions. The raw feed and the calcined clay samples are all characterized...... experimentally and a mathematical model is also developed to predict the conversion of the clay particles. The model properly accounts for the particle–ambient flow interaction and numerically solves all the processes occurring within the clay particles. The model predictions are compared against the...

  15. From clay- to organoclay-film modified electrodes: tuning charge selectivity in ion exchange voltammetry

    International Nuclear Information System (INIS)

    The surface of two natural smectite-type clay samples was chemically modified by covalent grafting of amine groups, by reaction with γ-aminopropyltriethoxysilane, which were easily protonated in HCl medium. Multisweep cyclic voltammograms of clay-film modified glassy carbon electrodes made of either the raw clays or the propylammonium-functionalized samples exposed to Ru(NH3)63+ or Fe(CN)63- electroactive probes were obtained. The results indicated a permselective behavior of these clay and organoclay-films based on either favorable or unfavorable electrostatic interactions. The cation-exchanging raw clay film modified electrodes exhibited accumulation properties for Ru(NH3)63+ species while rejecting Fe(CN)63-, whereas the anion-exchanging organoclay coatings acted as a barrier against Ru(NH3)63+ while increasing dramatically the concentration of Fe(CN)63- species at the electrode surface. Strong binding of the probe to the organoclays resulted in a potential shift of ca. 0.1 V of the voltammetric signals characteristic of the Fe(CN)63-/4- couple in the anodic direction. Their good preconcentration efficiency at low analyte concentration highlighted their interest for electroanalytical applications

  16. Rheological properties of different minerals and clay soils

    Directory of Open Access Journals (Sweden)

    Dolgor Khaydapova

    2015-07-01

    Full Text Available Rheological properties of kaolinite, montmorillonite, ferralitic soil of the humid subtropics (Norfolk island, southwest of Oceania, alluvial clay soil of arid subtropics (Konyaprovince, Turkey and carbonate loess loam of Russian forest-steppe zone were determined. A parallel plate rheometer MCR-302 (Anton Paar, Austria was used in order to conduct amplitude sweep test. Rheological properties allow to assess quantitatively structural bonds and estimate structural resistance to a mechanical impact. Measurements were carried out on samples previously pounded and capillary humidified during 24 hours. In the amplitude sweep method an analyzed sample was placed between two plates. The upper plate makes oscillating motions with gradually extending amplitude. Software of the device allows to receive several rheological parameters such as elastic modulus (G’, Pa, viscosity modulus (G", Pa, linear viscoelasticity range (G’>>G”, and point of destruction of structure at which the elastic modulus becomes equal to the viscosity modulus (G’=G”- crossover. It was found out that in the elastic behavior at G '>> G " strength of structural links of kaolinite, alluvial clay soil and loess loam constituted one order of 105 Pa. Montmorillonit had a minimum strength - 104 Pa and ferrallitic soil of Norfolk island [has] - a maximum one -106 Pa. At the same time montmorillonite and ferralitic soil were characterized by the greatest plasticity. Destruction of their structure (G '= G" took place only in the cases when strain was reaching 11-12%. Destraction of the kaolinite structure happened at 5% of deformation and of the alluvial clay soil and loess loam - at 4.5%.

  17. Synthetic clay-magnetite aggregates designed for controlled deposition experiments

    Science.gov (United States)

    Feinberg, J. M.; Galindo-Gonzalez, C.; Kasama, T.; Cervera, L.; Posfai, M.; Harrison, R. J.; Dunin-Borkowski, R. E.

    2007-12-01

    The behavior of magnetic particles in fluid environments is key to the acquisition of detrital remanence magnetization and is essential to a multitude of industrial applications. This study introduces a series of synthetic clay-magnetite aggregates whose physical attributes can be tailored for controlled depositional experiments. We describe the mineralogical structure and magnetic behavior of montmorillonite platelets coated with nanometer-scale magnetite crystals using both electron microscopy and rock magnetism techniques. Selected area electron diffraction of the magnetite and the montmorillonite host shows no evidence of preferred orientation or oriented aggregation. Grain size distributions of magnetite in three different clay-magnetite assemblages were directly measured using conventional bright-field transmission electron microscopy. The spacing of the magnetite grains and their three-dimensional distribution around individual clay platelets was imaged using a tomographic reconstruction generated from high-angle annular dark-field (HAADF) images. The grain size distributions determined from the bright-field images and the tomographic reconstruction agree within error with estimates derived from magnetic granulometry techniques based on magnetic hysteresis and low-field susceptibility measurements. All three samples behave superparamagnetically at room temperature, and display increasing levels of single domain behavior as the samples are cooled to liquid nitrogen temperatures (- 195°C). Off-axis electron holography images show that superparamagnetic grains are also stabilized into flux closure structures at -195°C. The average spacing between adjacent magnetite crystals and the overall platelet shape of the aggregates creates an anisotropy of magnetic susceptibility that allows assemblages to align with external magnetic fields at room temperature. By adjusting the dimensions and concentrations of the magnetite grains in these aggregates, we can create

  18. Clay based superior aggregate for making light construction

    International Nuclear Information System (INIS)

    Aggregate is defined as material consisting of solid minerals with grain size ranging from sand to gravel. This material is usually used for filling components of concrete. Clay based aggregate has special properties that can be useful for making light construction in wet environment. Concrete build using the aggregate is not impermeable, but it can adsorb water in significant amount, so that is very useful to be used as paving block for walker zone (trotoir) and zone surrounding swimming pool. Laboratory test results show that the aggregate has grain size in zone 1 type with specific gravity between 1360 - 1840 kg/cm3. Its abrasive factor about 35.32 % in average and it can be used as building material for light construction. Concrete with mixing ratio cement/aggregate of 1 to 6 with slump condition 3 to 6 cm and curing time of 28 days indicates compressive strength of 10 N/cm3. Qualitative cost analysis reflected that the paving block production cost is relatively low and it will be more profitable if they are product from failed pentile having fail between 10 to 30 %

  19. 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.

  20. BLOCK H-MATRICES AND SPECTRUM OF BLOCK MATRICES

    Institute of Scientific and Technical Information of China (English)

    黄廷祝; 黎稳

    2002-01-01

    The block H-matrices are studied by the concept of G-functions, several concepts of block matrices are introduced. Equivalent characters of block H-matrices are obtained. Spectrum localizations claracterized by Gfunctions for block matrices are got.

  1. Clay Mineralogy of Shallow Core Sediments of Lake Acigöl, Denizli, Turkey

    Science.gov (United States)

    Budakoglu, Murat; Karaman, Muhittin; Geredeli, Serpil; Unal, Hatice; Abdelnasser, Amr; Kiran Yildirim, Demet

    2014-05-01

    Lake Acıgöl is a hypersaline and active industrial salt production lake located in Denizli, Turkey. Lake Acıgöl has been investigated to elucidate the distribution clay minerals under the saline conditions of the lake and carbonate and ophiolitic rocks controlled lake basin. The lake is very shallow and generally characterized by an un-stratified and whole oxygenated water table. Determination clay minerals in the bulk samples via XRD method was not possible due to the their small amount. Therefore, the sequential clay enrichment procedure applied to the bulk samples such as sample dispersion, removal of soluble salts and ions, and particle-size fractionation. The XRD analyses of normal, glycolated and heat-treated shallow core samples show that the dominant clay minerals in the samples to be illite, including the swelling montmorillonite and kaolinite minerals are encountered less frequently. Glauberite, Blodite, Dansite and Nickelblodite have been also identified as soda minerals by XRD studies.

  2. A comparison of four different block bootstrap methods

    Directory of Open Access Journals (Sweden)

    Boris Radovanov

    2014-12-01

    Full Text Available The paper contains a description of four different block bootstrap methods, i.e., non-overlapping block bootstrap, overlapping block bootstrap (moving block bootstrap, stationary block bootstrap and subsampling. Furthermore, the basic goal of this paper is to quantify relative efficiency of each mentioned block bootstrap procedure and then to compare those methods. To achieve the goal, we measure mean square errors of estimation variance returns. The returns are calculated from 1250 daily observations of Serbian stock market index values BELEX15 from April 2009 to April 2014. Thereby, considering the effects of potential changes in decisions according to variations in the sample length and purposes of the use, this paper introduces stability analysis which contains robustness testing of the different sample size and the different block length. Testing results indicate some changes in bootstrap method efficiencies when altering the sample size or the block length.

  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. Microbial incidence on copper and titanium embedded in compacted bentonite clay

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Joergen; Lydmark, Sara; Edlund, Johanna; Paeaejaervi, Anna; Pedersen, Karsten (Microbial Analytics Sweden AB (Sweden))

    2011-10-15

    The incidence of bacteria on metal surfaces was examined in an experimental setting simulating conditions of the proposed Swedish concept for disposal of spent nuclear fuel. Titanium and copper rods were embedded in compacted bentonite clay saturated with groundwater collected at a depth of 450 m. Bentonite blocks were exposed to an external flux of groundwater with or without added lactate or H{sub 2} for up to 203 days. Bacterial accumulation on metal rods and in the surrounding bentonite was analyzed using real-time quantitative PCR (qPCR), with genetic markers for overall bacterial presence (16S rDNA) as well as specific for sulfate-reducing bacteria (apsA). Clay species composition was analyzed by cloning and sequencing 16S rDNA extracted from the clay. Results suggest limited bacterial accumulation on metal surfaces, amounting to a maximum of approximately 106 apsA copies cm-2, corresponding to a 3.7% coverage of metal surfaces. Bacterial species composition appeared to be a mix of species originating from the bentonite clay and from the added groundwater, including an apparently high proportion of sulfate-reducing bacteria. While titanium surfaces exhibited higher bacterial presence than did copper surfaces, neither the degree of bentonite compaction nor the addition of lactate or H{sub 2} appeared to have any effect on the bacterial incidence on metal surfaces

  6. Features of Clay Minerals in the YSDP102 Core on the Continental Shelf of the Southeast Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    JIANG Xuejun; QU Gaosheng; LI Shaoquan

    2004-01-01

    Ninety-eight clay mineral samples from the YSDP102 core were analyzed by x-ray diffractometer to study the four clay minerals: illite, chlorite, kaolinite and smectite. Twenty-eight samples had been analyzed on the laser particle-size analyzer to reveal the particle features of the sediments. Distribution of the clay minerals and the particle characteristics in the YSDP102 core show that the core experienced three different depositional periods and formed three different sedimentary intervals due to different sediment sources and different depositional environments. Features of the clay minerals and the heavy minerals in the YSDP102 core indicate that coarse-grained sediments and fine-grained sediments result from different sources. The Yellow Sea Warm Current has greatly influenced the sedimentary framework of this region since the current's formation.

  7. Detailed mineralogical characterization of the Bullfrog and Tram members USW-G1, with emphasis on clay mineralogy

    Energy Technology Data Exchange (ETDEWEB)

    Bish, D.L.

    1981-10-01

    The detailed mineralogy of the Bullfrog and Tram Members of the Crater Flat Tuff from drill hole USW-G1 has been examined, primarily to characterize fully the amounts and types of clay minerals in the tuffs and the possible effects clay minerals have on rock properties. Results of bulk sample x-ray diffraction analyses agree closely with previous determinations, although slightly higher clay mineral contents were found in this study. X-ray diffraction analysis of fine fractions revealed that the clay minerals in the tuffs are sodium-saturated montmorillonite-beidellites with typical layer charges and no high-charge layers. These smectites are found in virtually all samples of the Bullfrog and Tram, and there is no correlation between the amounts of smectites and the amounts of zeolite, quartz, and feldspar. Smectites are present in both welded and nonwelded horizons and are scarce in some zones with slight-to-absent welding.

  8. Detailed mineralogical characterization of the Bullfrog and Tram members USW-G1, with emphasis on clay mineralogy

    International Nuclear Information System (INIS)

    The detailed mineralogy of the Bullfrog and Tram Members of the Crater Flat Tuff from drill hole USW-G1 has been examined, primarily to characterize fully the amounts and types of clay minerals in the tuffs and the possible effects clay minerals have on rock properties. Results of bulk sample x-ray diffraction analyses agree closely with previous determinations, although slightly higher clay mineral contents were found in this study. X-ray diffraction analysis of fine fractions revealed that the clay minerals in the tuffs are sodium-saturated montmorillonite-beidellites with typical layer charges and no high-charge layers. These smectites are found in virtually all samples of the Bullfrog and Tram, and there is no correlation between the amounts of smectites and the amounts of zeolite, quartz, and feldspar. Smectites are present in both welded and nonwelded horizons and are scarce in some zones with slight-to-absent welding

  9. Study of the feasibility of the utilization of clays from Poco Fundo (MG) for its use in bricks fabrication

    International Nuclear Information System (INIS)

    This work aimed to make an analysis of mineralogical (Macroscopic Description and X-Ray Diffraction), chemical (X-Ray Fluorescence and Organic Carbon Analysis) and ceramic (Particle Size Distribution, Mechanical Resistance, Water Absorption, Apparent Porosity, among others) properties of the alluvial clays collected in Poco Fundo county - Minas Gerais State, Brazil - in order to confirm the feasibility of these clays for bricks manufacturing. There were collected 4 samples from the main potteries of the county, and they were nominated PF-01, PF-02, PF-03 and MAC-01. The clays from these region display high content of quartz, kaolinite and present refractory behavior, and the alkalis content (Na2O and K2O) is low, because the studied area suffered an intense weathering process. The sample PF-03 presented the most promising ceramic results, mainly due to the lower content in silica and higher amounts of organic matter, denoting a clay coming from a swampy area. (author)

  10. 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

  11. 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

  12. 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)

  13. 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.

  14. 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

  15. Lesson Thirteen Trifascicular Block

    Institute of Scientific and Technical Information of China (English)

    鲁端; 王劲

    2005-01-01

    @@ A complete trifascicular block would result in complete AV block. The idio ventricular rhythm has a slower rate and a wide QRS complex because the pacemaker is located at the peripheral part of the conduction system distal to the sites of the block1. Such a rhythm may be difficult to differentiate from bifascicular or bundle branch block combined with complete block at a higher level such as the AV node or His bundle2. Besides a slower ventricular rate, a change in the morphology of the QRS complex from a previous known bifascicular pattern would be strongly suggestive of a trifascicular origin of the complete AV block3. A His bundle recording is required for a definitive diagnosis, however.

  16. 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)

  17. 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)

  18. Processing and characterization of polyethylene/Brazilian clay nanocomposites

    International Nuclear Information System (INIS)

    Nanocomposites containing polyethylene (PE) and montmorillonite clay organically modified (OMMT) with quaternary ammonium salts were obtained via direct melt intercalation. A montmorillonite sample from the Brazilian state of Paraiba was treated with four different types of quaternary ammonium salts. After the treatment, the powder was characterized by X-ray diffraction and scanning electron microscopy. The dispersion and morphologies of OMMT within PE were investigated by X-ray diffraction and transmission electron microscopy. The results revealed the formation of intercalated montmorillonite layers in the PE matrix. The thermal stability and flammability of the PE/montmorillonite clay nanocomposites were measured by thermogravimetry and horizontal burning tests for HB classification, Underwrites Laboratories (UL 94), respectively. It was shown that the samples do not degrade at the processing temperature. By adding only 3 wt.% montmorillonite, the burning rate of the nanocomposites was reduced by 17%, and, in general, the tensile test showed that the yield strength and modulus of the nanocomposites are close to the pure PE. However, for a selected salt for MMT treatment the mechanical properties of nanocomposites were improved

  19. Distribution of Clay Minerals in Light Coal Fractions and the Thermal Reaction Products of These Clay Minerals during Combustion in a Drop Tube Furnace

    Directory of Open Access Journals (Sweden)

    Sida Tian

    2016-06-01

    Full Text Available To estimate the contribution of clay minerals in light coal fractions to ash deposition in furnaces, we investigated their distribution and thermal reaction products. The light fractions of two Chinese coals were prepared using a 1.5 g·cm−3 ZnCl2 solution as a density separation medium and were burned in a drop-tube furnace (DTF. The mineral matter in each of the light coal fractions was compared to that of the relevant raw coal. The DTF ash from light coal fractions was analysed using hydrochloric acid separation. The acid-soluble aluminium fractions of DTF ash samples were used to determine changes in the amorphous aluminosilicate products with increasing combustion temperature. The results show that the clay mineral contents in the mineral matter of both light coal fractions were higher than those in the respective raw coals. For the coal with a high ash melting point, clay minerals in the light coal fraction thermally transformed more dehydroxylation products compared with those in the raw coal, possibly contributing to solid-state reactions of ash particles. For the coal with a low ash melting point, clay minerals in the light coal fraction produced more easily-slagging material compared with those in the raw coal, playing an important role in the occurrence of slagging. Additionally, ferrous oxide often produces low-melting substances in coal ash. Due to the similarities of zinc oxide and ferrous oxide in silicate reactions, we also investigated the interactions of clay minerals in light coal fractions with zinc oxide introduced by a zinc chloride solution. The extraneous zinc oxide could react, to a small extent, with clay minerals in the coal during DTF combustion.

  20. Block Advertisement Protocol

    OpenAIRE

    Nemirovsky, Danil

    2015-01-01

    Bitcoin, a decentralized cryptocurrency, has attracted a lot of attention from academia, financial service industry and enthusiasts. The trade-off between transaction confirmation throughput and centralization of hash power do not allow Bitcoin to perform at the same level as modern payment systems. Block Advertisement Protocol is proposed as a step to resolve this issue. The protocol allows block mining and block relaying to happen in parallel. The protocol dictates a miner to advertise the ...

  1. 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

  2. Modeling selenite adsorption envelopes on oxides, clay minerals, and soils using the triple layer model

    Science.gov (United States)

    Selenite adsorption behavior was investigated on amorphous aluminum and iron oxides, clay minerals: kaolinite, montmorillonite, and illite, and 45 surface and subsurface soil samples from the Southwestern and Midwestern regions of the USA as a function of solution pH. Selenite adsorption decreased ...

  3. Clay Mineral Distribution Patterns of Tertiary Continental Oil-bearing Basins in China

    Institute of Scientific and Technical Information of China (English)

    Zhao Xingyuan

    1996-01-01

    @@ Induction This paper studies the clay mineral distribution patterns of Tertiary continental oil-bearing basins in China. More than 9 000 shale samples from Paleogene (E) to Neogene (N) Series distributed in Bohai Gulf, Subei, Jianghan,Nanxiang, Zhoukou, Sanshui, Beibu Bay, East China Sea,Hetao, Juiquan, Qaidam and Tarim basins, and so on.

  4. Clay mineral stratigraphy of Miocene to recent marine sediments in the central Mediterranean

    NARCIS (Netherlands)

    Visser, J.P. de

    1992-01-01

    X-ray diffraction analyses were made of the smaller than 2 J..Lm fraction from about 1250 samples of the central Mediterranean Miocene to Recent and the southeastern North-Atlantic Miocene in order to reconstruct climatic changes. Relative quantities of the clay minerals chlorite, illite, pyrophylli

  5. Modeling selenate adsorption behavior on oxides, clay minerals, and soils using the triple layer model

    Science.gov (United States)

    Selenate adsorption behavior was investigated on amorphous aluminum oxide, amorphous iron oxide, goethite, clay minerals: kaolinites, montmorillonites, illite, and 18 soil samples from Hawaii, and the Southwestern and the Midwestern regions of the US as a function of solution pH. Selenate adsorpti...

  6. Polyacrylamide effects on aggregate and structure stability of soils with different clay mineralogy

    Science.gov (United States)

    Adding anionic polyacrylamide (PAM) to soils stabilizes existing aggregates and improves bonding between and aggregation of soil particles. However, the dependence of PAM efficacy as an aggregate stabilizing agent with soils having different clay mineralogy has not been studied. Sixteen soil samples...

  7. Lability of soil organic carbon in tropical soils with different clay minerals

    DEFF Research Database (Denmark)

    Bruun, Thilde Bech; Elberling, Bo; Christensen, Bent Tolstrup

    2010-01-01

    of SOC in tropical soils with contrasting clay mineralogy (kaolinite, smectite, allophane and Al-rich chlorite). Soil was sampled from A horizons at six sites in humid tropical areas of Ghana, Malaysian Borneo and the Solomon Islands and separated into fractions above and below 250 µm by wet sieving...

  8. Study on the maturation at ambient temperature of brazilian pillared smectite clays

    International Nuclear Information System (INIS)

    Eighteen smectite clays were treated with aluminium-based pillaring agents and pillared through calcination under 400 deg C for 3 hours. The interlayer distance was characterized by X-ray diffraction and treated samples were aged at room temperature for ten months when the interlayer distances were measured again and compared with the former ones. (author)

  9. Comparative structural stability of natural clays and zeolites in contact with 60Co2+ aqueous solutions

    International Nuclear Information System (INIS)

    The ability of synthetic and natural Mexican zeolites and clays to remove radioactive Co from aqueous solutions is discussed. In the various samples, crystallinity was determined by X-ray diffraction. The amount of radionuclide sorbed by the aluminosilicates was determined by γ-spectrometry. (author) 4 refs.; 1 tab

  10. Characterization of the porosity in Opalinus Clay using ion beam polishing and SEM imaging - First results

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Full text entered in this record: In trying to cope with the increasing energy demand and at the same time trying to reduce CO2 emissions, there is renewed interest in the use of nuclear energy. Clay rich formations are known for their low permeability, illustrated by the fact that they form seals for hydrocarbons, confine and separate aquifers and protect deep groundwater resources from contamination, and clay-stones can hence act as a potentially good candidate for the long-term storage of radioactive waste. In the Mont Terri Rock Laboratory, Switzerland, the Opalinus Clay is investigated thoroughly (since 1996), with the aim to analyze its geological, hydrogeological, geochemical and rock mechanical properties and to observe how these properties change during the excavation of galleries, heating of the formation and emplacement of buffer material. Detailed investigation of the morphology of the pore space in clay is a key factor in understanding the sealing capacity, coupled flows, capillary processes and associated deformation present in clay rich layers. Using novel methods, our study reports direct, high-resolution observations and description of porosity in Opalinus Clay. Since clay is a delicate material, one of the key problems when observing the porosity of clay under a scanning electron microscope (SEM) is the sample preparation. To protect the microstructure of the clay, our samples are slowly dried at room temperature and under controlled conditions. Thereafter, an ion beam polisher (Broad Ion Beam - BIB) is used to produce high quality cross-sections without damages of microstructures. The produced cross-sections are then suitable for pore space investigation at high resolution by using a SEM. In order to optimize the processing of samples, the representative elementary area (REA) of BIB-polished cross-sections need to be determined first. A first step, in determining the REA for the mineral

  11. The Densification and Diametral Compression Strength of IsiOgwuta Clay

    Directory of Open Access Journals (Sweden)

    J. E. O. Ovri

    2016-07-01

    Full Text Available The diametral compression strength of clay was investigated. The clay sample was analyzed to ascertain its chemical composition and mineralogical constituent. The diametral clay discs were produced using a uniaxial cold pressing hydraulic press and sintered at a predetermined temperature and time (1200℃ and 15 minutes. Two diameters (D of discs of 23mm and 29mm were used with varying thicknesses (3mm-10mm. The effect of disc thickness with intent to qualitatively define the plane stress and the plane strain fracture conditions of the clay was undertaken. The plane stress condition was obtained by discs with thickness ≤ 1 ⁄ 4 D for 23mm and 29mm whilst the plane strain condition was obtained by testing discs of thickness > 1 ⁄ 4 D. The diametral compression strength of discs of thicknesses 3 −10mm gave a range of 14.6− 5.5MPa for samples of 23mm diameter whilst a range of 5.8 − 2.2MPa was obtained for samples of 29mm diameter. Greater numbers of 29mm diameter samples failed in the normal tensile fracture mode whilst more samples of 23mm diameter failed in the triple-cleft fracture mode. 23mm diameter discs gave higher values of Weibull moduli in comparison with the values obtained for discs of 29mm diameter indicating the flaws sampled in the 23mm diameter were of the same severity. Pores were observed to be singularly effective as initiation sites for failure as shown by the negative slope of the effect of porosity on the strength of clay.

  12. Relationship between the Morphology and Physico-Mechanical Properties of Polyethylene/Clay Nanocomposites

    International Nuclear Information System (INIS)

    Rheology, morphology and thermal behavior of HDPE/Clay nanocomposites were studied. The mechanical properties of these materials including tensile and creep behaviors were also taken into account. Different PE-g-MA samples with different MA contents and different rheological properties were laboratory synthesized and used as compatibilizer of PE and Clay. The results of X-ray diffraction in conjunction with the results of transmission electron microscopy (TEM) analysis indicated that, increasing in degree of grafted MA increases the penetration of PE chains onto the clay interlayer leading to intercalation and exfoliation. The intercalated and especially exfoliated nanocomposites exhibited higher viscosity and elasticity in particular at low frequency ranges, showing the formation of three dimensional networks with high interfacial interaction. The presence of such a network was evidenced by tand studies where the pseudo-solid like behavior was observed for exfoliated nanocomposites. From these results it was demonstrated that the linear viscoelastic properties of the nanocomposites have a reliable sensitivity to the extent of clay dispersion and they can be used as indirect method in the prediction of the morphology and therefore thermal and mechanical behavior of the nanocomposites. Incorporation of clay decreased the onset temperature of degradation due to the Hofmann elimination reaction, but increased remarkably the mid-point of the degradation temperature. Our laboratory synthesized intercalated nanocomposites displayed higher thermal stability than those of exfoliated samples. This was attributed to the barrier effect of clay layers to oxygen and volatile products, during the degradation of part of polymer chains which was intercalated in clay interlayer. Interestingly the results showed that the effect of Hofmann elimination reaction which decreases the onset temperature degradation of modified clay nanocomposites, can effectively be eliminated using a

  13. Laboratory hydro-mechanical characterisation of Boom Clay at Essen and Mol

    International Nuclear Information System (INIS)

    Boom Clay has been selected as a potential host rock formation for the geological disposal of radioactive waste in Belgium. In the present work, the hydro-mechanical behaviour of Boom Clay samples from the borehole Essen-1 at a depth of 220-260 m and from HADES that is the underground rock laboratory at Mol in Belgium, at 223-m depth was investigated in the laboratory by performing low pressure odometer tests (vertical effective stress ranging from 0.05 to 3.2 MPa), high pressure odometer tests (vertical effective stress ranging from 0.125 to 32 MPa), isotropic consolidation tests (confining effective stress ranging from the in situ stress to 20 MPa) and triaxial shear tests. It has been observed that the mineralogy, geotechnical properties and hydro-mechanical behaviour of Boom Clay from Essen at 227-m, 240-m and 248-m depths are similar to that of Boom Clay from Mol. As in the case of Boom Clay at Mol, the failure envelope of Boom Clay at Essen in the p'- q plane is not linear. The slope of the portion beyond the pre-consolidation stress of Boom Clay from Essen is almost the same as that from Mol, suggesting a similar internal friction angle of about 13 deg. The compression curves (void index Iv versus logarithm of vertical stress) beyond the pre-consolidation stress are the same for both samples from Mol and Essen, and situated between the intrinsic compression line (ICL) and the sedimentation compression line (SCL). The yield stress determined from odometer tests seems to be stress-path dependent and lower than the pre-consolidation stress. Thus determining the over-consolidation ratio (OCR) using the yield stress value would lead to an incorrect estimate. From a practical point view, the laboratory test results from Essen and their comparison with those from Mol provide important information regarding the transferability of knowledge on Boom Clay at different sites, taking into account the fact that most investigations have been carried out on Boom Clay at Mol

  14. In situ corrosion studies on candidate container materials for the underground disposal of high level radioactive waste in Boom Clay

    International Nuclear Information System (INIS)

    SCK·CEN has developed in the early 1980's, with the support of NIRAS/ONDRAF and EC, an extensive in situ corrosion program to evaluate the long-term corrosion behavior of various candidate container materials for the disposal of conditioned high-level radioactive waste and spent fuel. The in situ corrosion experiments were performed in the underground research facility, HADES, situated in the Boom Clay formation at a depth of 225 meters below ground level. These experiments place the samples either in direct contact with clay (type I), in a humid clay atmosphere (type 2), or in a concrete saturated clay atmosphere (type 3). During the period 1985--1994, twelve in situ corrosion experiments were installed in the underground laboratory. The exploitation of these experiments ended in 1996. All samples were recuperated and analyzed. The purpose of this paper is to summarize and discuss the results from the type 1 corrosion experiments (samples in direct contact with Boom Clay). Surface analyses tend to indicate that the so-called corrosion-resistant materials, e.g. stainless steels, Ni- and Ti-alloys, remain intact after exposure to Boom Clay between 16 and 170 C, whereas carbon steel presents significant pitting corrosion. Carbon steel seems to be unsuitable for the Belgian repository concept (pits up to 240microm deep are detected after direct exposure to the argillaceous environment for 2 years at 90 C). The stainless steels look very promising candidate container materials

  15. Investigation of properties of polyethylene/clay nanocomposites prepared by new in situ Ziegler-Natta catalyst

    International Nuclear Information System (INIS)

    This paper is devoted to investigation of morphological and physical-mechanical properties of polyethylene (PE)/clay nanocomposites prepared via in situ polymerization method using bi-supported Ziegler-Natta catalyst. Bentonite type clay and MgCl2 (ethoxide type) were used as the support of TiCl4. Catalyst support and polymerization process have been done in slurry phase using Triisobutylaluminum as the co-catalyst. The microstructure of the nanocomposites was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM indicated that almost fully exfoliated PE/clay nanocomposites were produced successfully using this method. According to permeability measurements, it was found that oxygen permeability values of the nanocomposite samples prepared with in situ polymerization method were dropped more than 200% introducing only 1 wt% clay to polymeric matrix. Differential scanning calorimetry (DSC) results indicated that the crystallization temperatures of samples are significantly higher than that of virgin PE. Moderate thermal stability enhancement of in situ polymerized nanocomposites was confirmed using thermogravimetric analysis (TGA).The storage modulus, Young's modulus and tensile strength of prepared samples were increased where the toughness was declined slightly. It seems that good dispersion and exfoliation of clay during polymerization should be responsible to get more effective reinforcing properties for clay in this method comparing to melt blending method for preparation of polyethylene nanocomposites.

  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. Clay minerals assemblage in the Neogene fluvial succession of the Pishin Belt, Pakistan

    DEFF Research Database (Denmark)

    Kasi, Aimal Khan; Kassi, Akhtar Muhammad; Friis, Henrik;

    2014-01-01

    indicate derivation of material from the Pre-Miocene sedimentary and meta-sedimentary terrains of the Pishin Belt. X-ray diffraction (XRD) analyses indicate that clay minerals in various mudstones and sandstone samples are identical and detrital in nature and include smectite, chlorite, illite, serpentine...... sedimentary and metasedimentary successions. The source of kaolinite seems to be pedogenic or lateritic. The clay minerals assemblage in mudstones and sandstones of the Dasht Murgha group, Malthanai formation and Bostan formation appears to have been derived from the nearby-exposed Pre-Miocence mafic...

  6. Chemical characterization of clay SRM by X-ray fluorescence – results comparison from different laboratories

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Appoloni

    2009-03-01

    Full Text Available Two Energy Dispersive X-ray Fluorescence equipments have been compared in order to verify its performance for clay characterization and potential application to the study in archaeometric field and industry. Two clay standard reference materials (SRM, IPT-42 and IPT-51 and one IAEA intercomparison sample were analyzed by two different methodologies and equipments. Asentamiento Universitario Zapala laboratory has a Shimadzu EDX-800HS bench top equipment and 13 elements from S to Zr were quantified in the standards. Applied Nuclear Physics Laboratory has a portable EDXRF system. It was possible to quantify K, Ti and Fe and qualitatively to identify Mn, Rb, Zn and Zr.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  9. 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...

  10. 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...

  11. 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...

  12. Dissolution kinetics of soil clays in sulfuric acid solutions: Ionic strength and temperature effects

    International Nuclear Information System (INIS)

    Highlights: • Acid sulfate dissolution of clay-rich sediments from inland acid sulfate site in flow-through reactor experiments at pH 1–4. • Enhanced Al and K release at the higher ionic strength of solutions compared to the lower ionic strength. • Acid neutralization capacity (ANC) of 1.11 kg H2SO4/tonne clay-rich sediment/day was provided at pH 1, 25 °C. • ANC provided at 45 °C by the same amount of clay-rich sediment was more than three times higher than the ANC at 25 °C. - Abstract: Significant amounts of sulfuric acid (H2SO4) rich saline water can be produced by the oxidation of sulfide minerals contained in inland acid sulfate soils (IASS). In the absence of carbonate minerals, the dissolution of phyllosilicate minerals is one of very few processes that can provide long-term acid neutralisation. It is therefore important to understand the acid dissolution behavior of naturally occurring clay minerals from IASS under saline–acidic solutions. The objective of this study was to investigate the dissolution of a natural clay-rich sample under saline–acidic conditions (pH 1–4; ionic strengths = 0.01 and 0.25 M; 25 °C) and over a range of temperatures (25–45 °C; pH 1 and pH 4). The clay-rich sample referred to as Bottle Bend clay (BB clay) used was from an IASS (Bottle Bend lagoon) in south-western New South Wales (Australia) and contained smectite (40%), illite (27%), kaolinite (26%) and quartz (6%). Acid dissolution of the BB clay was initially rapid, as indicated by the fast release of cations (Si, Al, K, Fe, Mg). Relatively higher Al (pH 4) and K (pH 2–4) release was obtained from BB clay dissolution in higher ionic strength solutions compared to the lower ionic strength solutions. The steady state dissolution rate (as determined from Si, Al and Fe release rates; RSi, RAl, RFe) increased with decreasing solution pH and increasing temperature. For example, the highest log RSi value was obtained at pH 1 and 45 °C (−9.07 mol g−1 s−1

  13. 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)

  14. Characterization and analysis of epoxy/clay nanotubes composites; Cacaterizacao e analise de compositos de epoxi, argila e nanotubos de carbono

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    An DGEBA epoxy matrix was used aiming to achieve a nanocomposite material, through the dispersion of (CNT) via mechanical stirring followed by sonication. In this work the following characterization were performed: mechanical characterization, differential scanning calorimetry (DSC), wide angle X-ray diffraction (WXRD) and scanning electron microscopy (SEM). The addition of CNT and modified clays promoted the increase of modulus of the epoxy matrix, and a synergistic effect between CNT and both clays could be presumed. SEM images of the fracture surface show the difference between the fracture surface area and the presence of clusters among the samples, allowing a correlation with the modulus of elasticity. X-ray diffractograms from 2{Theta} = 5 deg showed no peaks for modified clay samples, however it is possible to affirm that modified clay platelets are forming a less organized structure compared to the structure of the clay as natural in epoxy. (author)

  15. Advanced 2D and 3D Electron Microscopy Analysis of Clay/PP Nanocomposites

    DEFF Research Database (Denmark)

    Mosca, Alessandra; Roberts, Ashley; Daviðsdóttir, Svava;

    2011-01-01

    the improved macroscopic properties of nanocomposites. In this work, a clay/PP nanocomposite is studied by 2D bright field transmission electron microscopy (TEM) and 3D focussed ion beam – field emission gun scanning electron microscopy (FIB/FEG SEM). Materials and Methods A clay/polymer nanocomposite...... consisting of 3 wt% modified clay in a PP matrix was studied. Prior to microscopy analyses, SEM or TEM samples were cryo-microtomed to a flat surface or thin sections (70 nm), respectively. An FEI Titan T20 TEM microscope operating at 200 kV was used for 2D imaging. An FEI Helios focussed ion beam (FIB......) equipped with field emission gun (FEG) and through lens detector (TLD) was used for high resolution 3D imaging of the material via slice-and-view technique [2]. Image analysis was performed using Matlab. Results and Discussion Figure 1 (a) shows a TEM micrograph of a clay/PP nanocomposite, where the clay...

  16. Effect of Age and Environment on Strength of Old Baked Clay Bricks of Indus Valley Civilization

    Directory of Open Access Journals (Sweden)

    NAWAB ALI LAKHO

    2016-07-01

    Full Text Available This paper presents results of experimental investigations conducted on old baked clay bricks of Indus Valley civilization of tenth century. The object of this study is to evaluate the effect of age and environmental conditions on the strength of the baked clay bricks which are about 1000 years old. The brick samples were collected from six different archeological sites at the banks of old route of River Indus in district Sanghar, Sindh, Pakistan. These specimens were tested for apparent density, compressive strength, tensile strength, modulus of rupture and the weathering effects on them during the course of time. ASTM (American Society for Testing and Materials standard for baked clay bricks, based on compressive strength, suggests that the bricks of four sites can withstand severe weathering while the bricks of two sites are resistant to moderate weathering. These results were compared to the values of the corresponding data of bricks, of same period, obtained from the historical monuments of the world as reported in the literature. The comparison showed that the values of physical properties of old baked clay bricks of Indus valley civilization of tenth century are in agreement with that of old baked clay bricks of contemporary era. The results of this study could also be helpful for preservation of old archeological sites of Indus valley civilization.

  17. Removal of nickel on Bofe bentonite calcined clay in porous bed

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, M.G.A.; Neto, A.F. Almeida [UNICAMP/FEQ/DTF, Campinas, SP (Brazil); Gimenes, M.L. [UEM/CTC/DEQ, Campinas, SP (Brazil); Silva, M.G.C. da, E-mail: meuris@feq.unicamp.br [UNICAMP/FEQ/DTF, Campinas, SP (Brazil)

    2010-04-15

    Bentonite clays have been showing good adsorbing characteristics and are used as an alternative material in the removal of heavy metals. The purpose of this study is to evaluate the removal of nickel on Bofe bentonite calcined clay in porous bed. Firstly, a study was conducted to define the operation outflow, based on the minimum mass transfer zone (MTZ) obtained, useful (q{sub U}) and total adsorbed (q{sub T}) removal amounts and total nickel removal percentage (Rem (%)). Assays of nickel adsorption on clay were conducted according to a 2{sup 2} factorial design with three central points to evaluate the effect of the particle diameter and initial adsorbate concentration on variables q{sub U}, q{sub T} and Rem (%). Tests to obtain the adsorbent physical and chemical characteristics were performed on samples of Bofe clay in natura, calcined, and calcined submitted to nickel adsorption. This clay was characterized according to the following techniques: Energy Dispersive Spectroscopy (EDS), Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Fourier Transformed Infrared Spectroscopy (FTIR), Physisorption of N{sub 2} (BET), Helium Picnometry and Scanning Electron Microscope (SEM) with metal mapping.

  18. Permeability, Strength and Filtration Performance for Uncoated and Titania-Coated Clay Wastewater Filters

    Directory of Open Access Journals (Sweden)

    Masturi

    2012-01-01

    Full Text Available Problem statement: Wastewater problems continue to be a relevant issue, particularly in urban areas. One promising low-cost material for manufacturing porous ceramics as water filter is clay. Clays can be blended with other materials such as polymers to obtain functional ceramic materials. Approach: Ceramic wastewater filters were fabricated from clay using both sol-gel and simple mixing methods followed by hot-pressing and calcination. Polyethylene Glycol (PEG was used as a pore-forming agent. Results: Varying the clay:PEG ratio modified the membrane permeability between 1.65×10-16 m2 and 3.16×10-15 m2 for the sol-gel membranes and between 1.38×10-16 and 8.72×10-13 m2 for membranes prepared by simple mixing. The strength ranged from 0.28 MPa-1.71 MPa for the sol-gel membranes and from 0.05-0.90 MPa for samples prepared by simple mixing. The filtration performance was tested using aqueous solutions of Methylene Blue (MB. The concentrations of MB remaining in the solution varied from 0.98-1.44% for sol-gel filters and from 1.50-38.05% for filters prepared by simple mixing. Conclusion: We succeeded in making ceramic as filter from clay. The porous ceramic can be used to reducing concentration of pollutant simulated. The model introduced has succeeded to explain the experimental observations with percolation approximation.

  19. Treatment of Scumming Effects of Pottery Clay by Sodium Carbonate Addition

    Energy Technology Data Exchange (ETDEWEB)

    Wasanapiarnpong, T; Thueploy, A; Arayaphong, D [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Nilpairach, S, E-mail: thanakorn.w@chula.ac.t [National Center of Excellence for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University (Thailand)

    2011-10-29

    Earthenware pottery products made by using red plastic clay in Ratchaburi province of Thailand and fired at 850-1000 deg. C, always shows some blemishes, caused by scumming on the surface. This scumming contains calcium sulfate, contaminated in the raw clay as gypsum form. The addition of barium carbonate is a suggested solution to prevent this white stain. However, it is difficult for barium carbonate to spread throughout the clay so that it takes a long time to complete the reaction. This research aims to find the solution by using sodium carbonate as an alternative chemical. Sodium carbonate was mixed in the clay at 1wt% dissolved in distilled water controlled the moisture at 22 % by wet weight. The mixture was kneaded and aged for 24 h, then formed, dried and fired at 850-950 deg. C. The types and quantities of ion in mixed clay and deposited on the surface product were determined after drying. It was found that the white stain areas were diminished, as same as the result from the addition of barium carbonate. Moreover, the sample after firing at 950 deg. C had lower water absorption as 12.22%, higher three point bending strength as 32.53 MPa when compared to the addition of barium carbonate, which had higher water absorption as 15.58 % and lower three point bending strength as 25.25 MPa.

  20. R and D programme on radioactive waste disposal into a clay formation

    International Nuclear Information System (INIS)

    The present report presents the main results obtained during the period 1980-82 in the Belgian R and D work on geological disposal of conditioned radioactive waste in the boom clay beneath the Mol site. Multiple research projects have been continued: both experimental research in the field and in the laboratory and theoretical studies. A regional hydrological observation network has been set up which permitted an assessment of the hydrogeological system over- and underlying the Boom clay as well as the modelling of groundwater flow in the area. Clay samples collected during the drilling campaigns were submitted to a number of analyses with a view to chemical characterization and determination of geotechnical properties. Various studies were performed concerning the migration of radionuclides through the clay and an analytical computer model was developed. The corrosion behaviour of various candidate materials for HLW containers and repository linings were tested under different conditions possibly encountered in the clay formation. Furthermore, various backfill and sealing materials and mixtures have been selected and are being tested. Finally, the activities deployed for the safety analysis were continued, mainly concentrated upon two approaches: the probabilistic risk assessment and the performance assessment of a mined repository under normal evolution conditions

  1. Mineral potential of clays that cover the gypsum deposits in Araripina-PE region

    International Nuclear Information System (INIS)

    In the present work the applicability of the clays that cover the deposits of Gypsum Plaster in the region of Araripina - PE for use as the ceramic pigments and for bricks production in the red ceramic industry was analyzed. The clay minerals contained the illite, kaolinite and smectite, with high proportion of the last one. The possibility of industrial application of this mineral clay is considerable; however, the mining industries that mine and process the gypsum in the region do not take the clays into account as the potential mineral. In general, industries use the clay minerals in manufacturing processes or as key raw materials, or as the alternatives for some kinds of the chemical processing industries. This paper aims to highlight the potential of materials that cover the deposits of gypsum in reference. The material sampled from different deposit layers was characterized and the physical treatment of ore was applied. The results showed that the material analyzed can be used in various kinds of industry, such as the production of natural ceramic pigments. (author)

  2. 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

  3. 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...

  4. 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..

  5. Investigation of isothermal water infiltration into fired clay brick by scattered neutrons

    International Nuclear Information System (INIS)

    A method based on neutron scattering was proposed to investigate isothermal water infiltration in porous media. Two different kinds of fired clay bricks were investigated. While the sample absorb water, scattered neutrons from the different wetted regions, along the flow direction were continuously recorded. The results were discussed in terms of the theory of water infiltration in unsaturated porous media as well as by an anomalous diffusion approach. It was shown that the infiltration process in the Canadian clay brick (CCB) is Fickian and the water diffusivity was analytically determined, while it is non-Fickian in the Egyptian clay brick (ECB). The infiltration process in ECB can be modeled as a two stage Fickian process, at the low and high absorption times. The anomalous diffusion approach failed to describe the diffusion process in the ECB at all water contents. (author)

  6. Characterization of clays used in red ceramic in Sergipe State, Brazil

    International Nuclear Information System (INIS)

    Clays materials from Sergipe State were characterized by X-ray diffractometry and fluorescence, particle size and plasticity. Predominant minerals in twenty two samples were kaolinite, halloysite and quartz. Chemical composition ranges were: SiO2 49,5-77,1; Al2O3 10,4-28,3; Fe2O3 1,0-10,2; TiO2 0,4-1,2; P2O5 0,04-0,2; CaO 0,03-7,9; MgO 0,1-3,2; Na2O 0,04-2,3; K2O 0,7-3,8 found predominantly in the silt fraction. Plasticity ranged from 19,9 to 30,1%. Results allowed clay materials deposits to be arranged in categories such as: melting sources, quartz sources and those with higher iron oxides concentrations. These categories can be used for selecting clays for ceramic production. (author)

  7. Effect of surfactant concentration on organo clay and PET nanocomposites properties

    International Nuclear Information System (INIS)

    The influence of surfactant content on the properties of Argel bentonite and on the PET nanocomposites properties were evaluated in this study. The clay was organically modified by cation exchange reaction with cetyl trimethyl ammonium bromide salt (Cetremide) and then incorporated into the PET, in quantities of 1 wt %, by melting intercalation process. The samples were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG) and viscometry. According to the results it is evidenced that although all clays can be used in the PET nanocomposites preparation the organoclay obtained with a quantity of Cetremide equivalent to 120% of the CEC of the clay seems more suitable for nanocomposites preparation due the higher thermal stability of this one. (author)

  8. Characterized and cleaning process of montmorillonite clay from Parelhas, Rio Grande do Norte state, Brazil

    International Nuclear Information System (INIS)

    The application of montmorillonite nano composites has been improved in order to obtain dispersed phase with particles of nano metric dimensions. To obtain these nanoparticles, the clays must pass an effective purification process for removing unwanted materials, which would undermine the processes of intercalation and exfoliation of montmorillonite in a polymer matrix. This study intention to characterize and purify a montmorillonite clay from deposit recently discovered in the city of Parelhas in Rio Grande do Norte, through the separation of coarser materials by decantation followed by a chemical attack that promoted oxidation in samples where it was realized reduction of impurities such as organic matter and other substances that would hinder the achievement of nanoparticles. Under these conditions, the clay is suitable for the work as dispersed phase in a polymer matrix nano composite. The results were demonstrated by analysis of scanning electron microscopy (SEM), chemical analysis, BET and X-ray diffraction (XRD). (author)

  9. Block Scheduling Revisited.

    Science.gov (United States)

    Queen, J. Allen

    2000-01-01

    Successful block scheduling depends on provision of initial and ongoing instructional training. Teaching strategies should vary and include cooperative learning, the case method, the socratic seminar, synectics, concept attainment, the inquiry method, and simulations. Recommendations for maximizing block scheduling are outlined. (Contains 52…

  10. Geo-scientific characterisation of the Boom clay in the Netherlands in light of permanent confinement of radio-active waste

    International Nuclear Information System (INIS)

    properties of the Boom Clay is needed in order to establish: 1. the reactivity towards radioisotopes, 2. the physical properties that depend on sediment-geochemical characteristics and 3. the evolution of the Boom Clay at the geological time scale. The associated aims of the activities proposed therefore are: 1. to establish analytical data on the geochemical properties of the Boom Clay at a national scale, 2. to characterise the reactivity of the Boom Clay, 3. to characterise pore water in the boom Clay and groundwater in adjacent aquifer layers and 4. to set-up a prognosis on the long-term geochemical properties of the Boom Clay under anticipated future geological evolution of the Netherlands. The approach consists of: 1. a series of standard analyses on Dutch archive samples from the Boom Clay, 2. standard and non-standard analyses on newly collected samples, 3. sampling of wells having screens just above or below the Boom Clay and extracting pore water from fresh Boom Clay sediment samples and 4. desk and modelling study on long-term diagenesis of the Boom Clay. The results of this project will primarily be national, statistical data about the geochemical properties of the Boom Clay in the Netherlands and the groundwater above and below this geological layer incl. insight into its lateral and vertical variability. Additionally, detailed insight into the redox and sorption properties will be delivered when new drillings can be made. The two projects will be inter-linked with other projects under the OPERA research program. The geochemical and geohydrological information gained is input for the tasks that deal with reactive transport of radionuclides. The information is also relevant for project activities that deal with the physico-chemical properties and geomechanical aspects. Finally, the information gained will be used in scenario development and performance assessment. TNO and UU are also involved in these activities but other organisations are frequently more

  11. Sympathetic blocks for visceral cancer pain management

    DEFF Research Database (Denmark)

    Mercadante, Sebastiano; Klepstad, Pal; Kurita, Geana Paula; Sjogren, Per; Giarratano, Antonino

    2015-01-01

    The neurolytic blocks of sympathetic pathways, including celiac plexus block (CPB) and superior hypogastric plexus block (SHPB) , have been used for years. The aim of this review was to assess the evidence to support the performance of sympathetic blocks in cancer patients with abdominal visceral...... effects in comparison with a conventional analgesic treatment. In one study patients treated with superior hypogastric plexus block (SHPB) had a decrease in pain intensity and a less morphine consumption, while no statistical differences in adverse effects were found. The quality of these studies was...... generally poor due to several limitations, including sample size calculation, allocation concealment, no intention to treat analysis. However, at least two CPB studies were of good quality. Data regarding the comparison of techniques or other issues were sparse and of poor quality, and evidence could not be...

  12. 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.

  13. 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,...

  14. 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

  15. A GLE multi-block model for the evaluation of seismic displacements of slopes

    International Nuclear Information System (INIS)

    The paper describes a multi-block displacement model for the evaluation of seismic permanent displacements of natural slopes with slip surface of general shape. A rigorous limit equilibrium method of stability analysis is considered and an application to an ideal clay slope is presented including the effect of excess pore pressure build-up on the displacement response

  16. 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.

  17. 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.

  18. Incorporation of gypsum waste in ceramic block production: Proposal for a minimal battery of tests to evaluate technical and environmental viability of this recycling process.

    Science.gov (United States)

    Godinho-Castro, Alcione P; Testolin, Renan C; Janke, Leandro; Corrêa, Albertina X R; Radetski, Claudemir M

    2012-01-01

    Civil engineering-related construction and demolition debris is an important source of waste disposed of in municipal solid waste landfills. After clay materials, gypsum waste is the second largest contributor to the residential construction waste stream. As demand for sustainable building practices grows, interest in recovering gypsum waste from construction and demolition debris is increasing, but there is a lack of standardized tests to evaluate the technical and environmental viability of this solid waste recycling process. By recycling gypsum waste, natural deposits of gypsum might be conserved and high amounts of the waste by-product could be reused in the civil construction industry. In this context, this paper investigates a physical property (i.e., resistance to axial compression), the chemical composition and the ecotoxicological potential of ceramic blocks constructed with different proportions of clay, cement and gypsum waste, and assesses the feasibility of using a minimal battery of tests to evaluate the viability of this recycling process. Consideration of the results for the resistance to axial compression tests together with production costs revealed that the best formulation was 35% of plastic clay, 35% of non-plastic clay, 10% of Portland cement and 20% of gypsum waste, which showed a mean resistance of 4.64MPa. Energy dispersive X-ray spectrometry showed calcium and sulfur to be the main elements, while quartz, gypsum, ettringite and nacrite were the main crystalline compounds found in this formulation. Ecotoxicity tests showed that leachate from this formulation is weakly toxic toward daphnids and bacteria (EC(20%)=69.0 and 75.0, respectively), while for algae and fish the leachate samples were not toxic at the EC(50%) level. Overall, these results show that the addition of 20% of gypsum waste to the ceramic blocks could provide a viable substitute for clay in the ceramics industry and the tests applied in this study proved to be a useful tool

  19. 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 ...

  20. 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...

  1. Zeolites and clays behavior in presence of radioactive solutions

    International Nuclear Information System (INIS)

    Natural aluminosilicates have found application as selective ion exchangers for radioactive cations, present in liquid wastes arising from nuclear facilities. Among severals cations and complex mixtures of them, Co is a common constituent of liquid radioactive wastes. Two types of zeolites (Y zeolite, and natural mexican erionite), and two types of clays (natural bentonite, and Al-expanded bentonite (Al-B) were used. Previous to the experiments, the zeolites and the natural bentonite were stabilized to their respective Na+ form using 5N NaCl solution. 2Na+→ 60Co2+ ion exchange kinetics in zeolites and clays was followed by gamma spectrometry using a NaCl-Co(NO3)2 isonormal solution (0.1N) labeled with 60Co-Co(NO3)2 (100 μ Ci). Before and after experiments, the structural changes in the cristallinity of aluminosilicates were determined by X-ray diffraction. XRD analyzes show that the cristallinity of the aluminosilicates was not affected by ion exchange. After Co exchange the cell parameters were determined in all samples. The efficiency of zeolites, natual clays and expanded clays to remove cobalt ions from solutions depends on the ion echange capacity of the material. Results for long contacts time, 18 days, show that Co is more effectively removed by Y zeolite ( 4.07 wt %), followed by erionite (3.09 wt %), then bentonite ( 2.36 wt %) and finally expanded bentonite ( 0.70 wt %). In Y zeolite an unusual fast soportion uptake of 4.51 % wt Co was observed followed by a desorption process to 4.07 %. This effect is due to the different hydration degree of zeolites during the contact time between the zeolite and the 60Co solution. In erionite the exchange is lower than in Y-zeolite, frist because the Si/Al ratio is higher for erionite than for Y-zeolite and second because K ions in erionite cannot be exchanged during the stabilization of erionite in 5N NaCl solution. The low exchange in expanded bentonite was expected because its cation exchange capacity was

  2. Clay vein and its implication for uranium exploration activity in the northern part of the Alligator Rivers Uranium Field, northern Australia

    International Nuclear Information System (INIS)

    Clay veins have been found by uranium exploration drilling around the Black Rock uranium prospect in the northern part of the alligator Rivers Uranium Field (ARUF), northern Australia. The mineralogical and chemical features are described to clarify relations with uranium mineralization, because it is not accompanied by uranium mineralization. X-ray diffraction and chemical analysis for major elements indicate that the clay vein consists mainly of chlorite (clinochlore to ferroan clinochlore) and lesser mica clay mineral (t-1M dominant). The clay vein is compared with the clay alteration zone around the uranium deposits in ARUF in terms of mode of occurrence, mineral and chemical compositions. Mineral composition of the clay vein is only in accordance with that of the inner alteration halo of the clay alteration zone. It is, however, different from mineral composition of the outer alteration halo in terms of lack of Fe chlorite in the clay vein. Chemical composition of the clay vein is similar to that of the clay alteration zone, except for lack in the vein of high iron content which is observed in some samples of the alteration zone. As a whole, the feature of the clay vein corresponds to the inner alteration zone around the uranium deposit in ARUF. The mode of occurrence of the clay vein is very different from that of the clay alteration zone. Mode of occurrence, and mineral and chemical compositions of the clay vein resemble a chlorite vein in the Lower to Middle Proterozoic sandstone above the Jabiluka deposit, one of major uranium deposit in the ARUF. Because of the similarity between the clay and the chlorite veins, the clay vein is regarded as marginal facies of an alteration zone. The fluid that formed the clay vein is estimated to have been oxidized, because of the existence of hematite and ubiquitous Mg chlorite. This nature is in accordance with the mineralizing fluid that formed the inner alteration zone in the Nabarlek deposit. In conclusion, the vein

  3. Feasibility and Performance of Full-Scale In-situ Remediation of TCE by ERD in Clay Tills

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Damgaard, Ida; Chambon, Julie Claire Claudia;

    been applied. The results showed that the chlorinated solvent TCE was converted into its daughter products (cDCE, VC and ethene) but complete conversion of contaminants to ethene (as expected) was not achieved within a timeframe of 4 years. Large variation in the effect of ERD in the clay matrix......The feasibility and performance of full-scale applications of ERD in clay tills were investigated in a research project including 2 sites in Denmark, which have been undergoing remediation since 2006. At both sites organic substrates and bioaugmentation cultures have been injected in TCE-contaminated...... clay till. An integrated investigative approach consisting of water and clay core sample analysis, including stable isotopes and specific degraders, as well as analysis for chlorinated solvents, degradation products, donor fermentation products and redox-sensitive parameters combined with modelling has...

  4. Moessbauer study of fired Lishan clay and terra-cotta warriors and horses of Qin Dynasty (221 B.C.)

    International Nuclear Information System (INIS)

    The sherds of terracotta warriors and horses and Lishan clay were characterized by Moessbauer spectroscopy, XRD, XRF, NAA, thermal and chemical analyses. Lishan clay was testified as the original material of terracotta warriors and horses, the kilning of these warriors and horses was first carried out in an oxidizing atmosphere, and then changed to a predominantly reducing atmosphere. With refiring experiments, the temperatures of Q3 and Q4 samples were determined to be 830 ± 50 and 980 ± 50degC respectively. Transformations of Lishan clay were determined by firing in oxidizing and reducing atmospheres. The Moessbauer parameters of Lishan clay, which was taken after 2-24h firing, were changing up to 12h. (orig.)

  5. The role of clay minerals on the hardsetting properties of soils in the Carnarvon horticultural district of Western Australia

    International Nuclear Information System (INIS)

    Full text: We investigated the role of clay minerals on the hardsetting properties of soils used for intensive irrigated horticulture in the Carnarvon horticultural district of Western Australia. Hardsetting soils break down when wetted due to a combination of slaking and dispersion processes, resulting in a structureless mass of soil when dry. Soil samples were studied from several horizons from six profiles with hardsetting problems. On bulk samples, we measured the cation exchange capacity (CEC) and following treatment with sodium (Na), measured the tensile strength of (Na saturated) remoulded cores. On clay separates we measured the clay mineralogy using X-ray . diffraction (XRD) analysis and CEC by X-ray fluorescence (XRF) analysis after barium (Ba) saturation. Samples were also investigated using transmission electron microscopy (TEM). The tensile strength of the Na saturated remoulded cores was highly correlated (p ≤ 0.001) to both clay % and CEC of the soil. Lugo (1975) working with dried briquettes of soil materials produced similar results, and demonstrated that the increase in tensile strength adversely affected the stand of plants. When the tensile strength of the remoulded cores was compared to the CEC of the clay fractions, the soil clays with higher CEC had greater tensile strength than soils lower in CEC (p=0.09). Initial qualitative XRD results using the SIROQUANT method indicated that the soil clays mainly consisted of kaolinite with some illite, but very little smectite content. However the measured CEC's (by Ba saturation) were higher than expected and could not be explained on the basis of the illite and kaolinite contents. It was therefore inferred that interstratified smectite was also present. Using the proprietary software 'Traces', and a Pseudo-Voigt peak-shape algorithm, each XRD pattern was fitted with calculated peaks for the clay minerals present. Comparison with calculated patterns for interstratified illite/smectite (I/S) using

  6. Ion Exchange Resin and Clay Vitrification by Plasma Discharges

    International Nuclear Information System (INIS)

    The lack of treatment of a low and intermediate level radioactive waste (LILRW) lead us to propose a vitrification process based on a plasma discharge; this technique incorporates LILRW into a matrix glass composed of ceramic clays material. The Mexican Institute of Nuclear Research (ININ), uses an ion exchange resin IRN 150 (styrene-divinilbence copolymer) in the TRIGA MARK III nuclear reactor. The principal objective of this resin is to absorb particles containing heavy metals and low-level radioactive particles. Once the IRN 150 resin filter capacity has been exceeded, it should be replaced and treated as LILRW. In this work, a transferred plasma system was realized to vitrify this resin taking advantage of its high power density, enthalpy and chemical reactivity as well as its rapid quenching and high operation temperatures. In order to characterize the morphological structure of these clay samples, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Thermogravimetric analysis (TGA) techniques were applied before and after the plasma treatment

  7. Experimental investigations of the wettability of clays and shales

    Science.gov (United States)

    Borysenko, Artem; Clennell, Ben; Sedev, Rossen; Burgar, Iko; Ralston, John; Raven, Mark; Dewhurst, David; Liu, Keyu

    2009-07-01

    Wettability in argillaceous materials is poorly understood, yet it is critical to hydrocarbon recovery in clay-rich reservoirs and capillary seal capacity in both caprocks and fault gouges. The hydrophobic or hydrophilic nature of clay-bearing soils and sediments also controls to a large degree the movement of spilled nonaqueous phase liquids in the subsurface and the options available for remediation of these pollutants. In this paper the wettability of hydrocarbons contacting shales in their natural state and the tendencies for wettability alteration were examined. Water-wet, oil-wet, and mixed-wet shales from wells in Australia were investigated and were compared with simplified model shales (single and mixed minerals) artificially treated in crude oil. The intact natural shale samples (preserved with their original water content) were characterized petrophysically by dielectric spectroscopy and nuclear magnetic resonance, plus scanning electron, optical and fluorescence microscopy. Wettability alteration was studied using spontaneous imbibition, pigment extraction, and the sessile drop method for contact angle measurement. The mineralogy and chemical compositions of the shales were determined by standard methods. By studying pure minerals and natural shales in parallel, a correlation between the petrophysical properties, and wetting behavior was observed. These correlations may potentially be used to assess wettability in downhole measurements.

  8. Predictability of blocking

    International Nuclear Information System (INIS)

    Tibaldi and Molteni (1990, hereafter referred to as TM) had previously investigated operational blocking predictability by the ECMWF model and the possible relationships between model systematic error and blocking in the winter season of the Northern Hemisphere, using seven years of ECMWF operational archives of analyses and day 1 to 10 forecasts. They showed that fewer blocking episodes than in the real atmosphere were generally simulated by the model, and that this deficiency increased with increasing forecast time. As a consequence of this, a major contribution to the systematic error in the winter season was shown to derive from the inability of the model to properly forecast blocking. In this study, the analysis performed in TM for the first seven winter seasons of the ECMWF operational model is extended to the subsequent five winters, during which model development, reflecting both resolution increases and parametrisation modifications, continued unabated. In addition the objective blocking index developed by TM has been applied to the observed data to study the natural low frequency variability of blocking. The ability to simulate blocking of some climate models has also been tested

  9. Elemental Analysis and Natural Radioactivity Levels of Clay by Gamma Ray Spectrometer and Instrumental Neutron Activation Analysis

    OpenAIRE

    W. R. Alharbi; El-Taher, A.

    2016-01-01

    Due to increased global demand for clay, the present work involves the use of INAA for elemental analysis and pollutants concentration in clay. The samples were collected from Aswan in South Egypt. The samples were irradiated using the thermal neutrons “at the TRIGA Mainz research reactor” and at a neutron flux “of 7 × 10 n/cm s”. Twenty-six elements quantitatively and qualitatively were specified for the first time upon studying the samples. The elements determined are U, Th, Ta, Hf, Lu, Eu,...

  10. Effect of Kiwi Shell and Incubation Time on Mobility of Lead and Cadmium in Contaminated Clay Soil

    OpenAIRE

    Bahareh Lorestani; Chia Arjangi; Hajar Merrikhpour

    2014-01-01

    In this study, the effectiveness of kiwi shell was investigated to reduce the mobility of Lead and Cadmium in clay soil in different intervals. For this purpose a clay soil sample was contaminated with Lead and Cadmium in distinct dishes with 10 and 600 ppm concentrations respectively and mixed with 5% kiwi shell. Samples were placed in incubator, and then sampling of soil in incubator was performed in intervals 3 hours, 1, 3, 7, 14, 21 and 28 days. Heavy metals concentrations were determined...

  11. 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)

  12. 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).

  13. 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.

  14. Electrokinetic remediation of contaminated clay

    International Nuclear Information System (INIS)

    Electrokinetic remediation is a promising technology for contaminated clayey soils. In order to estimate the efficiency of process on different soils, knowing the interaction of simultaneous different processes are very important. The results of electrokinetic process are water flow, ion and species migration against an electrical field. In this paper the feasibility of phenol removal from kaolinite using electrokinetic remediation is investigated. Results of three one dimensional tests at constant current condition is presented. The tests were conducted for about 50 hours. Variations of ph, electrical gradient, electro osmotic flow and phenol concentration in anode and cathode chambers as well as soil specimen were measured. The efficiency of phenol removal along the soil specimen were calculated at the end of each test. In one case more than 80 percent of phenol removal was achieved from soil sample. Results indicated that electrokinetic remediation is suitable for phenol removal from contaminated clayey soils in short time. Further experiment needed to eva lute the efficiency of this technology on contaminant removal of natural polluted soils

  15. Block Cipher Analysis

    DEFF Research Database (Denmark)

    Miolane, Charlotte Vikkelsø

    ensurethat no attack violatesthe securitybounds specifiedbygeneric attack namely exhaustivekey search and table lookup attacks. This thesis contains a general introduction to cryptography with focus on block ciphers and important block cipher designs, in particular the Advanced Encryption Standard......(AES).Wedescribe the mostgeneraltypes ofblock cipher cryptanalysis but concentrate on the algebraic attacks. While the algebraic techniques have been successful oncertainstreamcipherstheirapplicationtoblock ciphershasnot shown any significant results so far. This thesis contributes to the field of algebraic attacks on...... algebraic results on small scale variants of AES. In the final part of the thesis we present a new block cipher proposal Present and examine its security against algebraic and differential cryptanalysis in particular....

  16. Interaction of clay and concrete plugs - Plugging of 5 m deep hole KA1621G01 at Aespoe

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Drawrite AB, Lund (Sweden); Luleaa Technical Univ., Luleaa (Sweden); Ramqvist, Gunnar [Eltekno AB, Figeholm (Sweden)

    2011-11-15

    Sealing of deep boreholes in repository rock is planned to be made by installing dense smectite clay plugs where the rock is low-permeable and casting concrete where the holes intersect water-bearing fracture zones. Such zones have to be stabilized before sealing starts because fragments of rock can otherwise fall off and make it difficult to bring equipment for concrete casting and clay plug units down. These parts of the holes are filled with concrete and clay plugs are then inserted up to the nearest fracture zone where concrete is filled to the required level etc. The role of the concrete in the hole and in the closest part of the surrounding fracture zone is to provide stable parts that are sufficiently fine-porous to prevent clay particles from contacting clay plugs to migrate into the fractures and be lost by erosion. While the larger parts of long clay plugs are believed to stay largely intact chemically for hundreds of thousands of years, the parts adjacent to concrete plugs may undergo changes and so can the concrete plugs themselves. The objective of the presently reported project was to identify the detailed processes and quantify associated changes in physical properties by investigating samples of clay and concrete from a 2.5 m long plug of clay over which an equally long concrete plug had been cast and left to rest for 3 years. The outcome of the investigations was that significant chemically induced changes in mineralogy and physical performance had occurred within a few centimetres distance from the clay/concrete contact but that virtually no changes had taken place at larger distance. A comprehensive laboratory study including X-ray diffraction (XRD), X-ray fluorescence (XRF) and electron microscopy study (SEM and TEM) on the sample material was performed including also dual beam (combined ion and electron) microscopy. It was found that the clay had infiltrated the contacting concrete plug after filling of the borehole since clay was detected both

  17. Speciation of uranium in surface-modified, hydrothermally treated, (UO{sub 2}){sup 2+}-exchanged smectite clays

    Energy Technology Data Exchange (ETDEWEB)

    Giaquinta, D.M.; Soderholm, L.; Yuchs, S.E.; Wasserman, S.R. [Argonne National Lab., IL (United States). Chemistry Div.

    1997-08-01

    A successful solution to the problem of disposal and permanent storage of water soluble radioactive species must address two issues: exclusion of the radionuclides from the environment and the prevention of leaching from the storage media into the environment. Immobilization of radionuclides in clay minerals has been studied. In addition to the use of clays as potential waste forms, information about the interactions of radionuclides with clays and how such interactions affect their speciations is crucial for successful modeling of actinide-migration. X-ray absorption spectroscopy (XAS) is used to determine the uranium speciation in exchanged and surface-modified clays. The XAS data from uranyl-loaded bentonite clay are compared with those obtained after the particle surfaces have been coated with alkylsilanes. These silane films, which render the surface of the clay hydrophobic, are added in order to minimize the ability of external water to exchange with the water in the clay interlayer, thereby decreasing the release rate of the exchanged-uranium species. Mild hydrothermal conditions are used in an effort to mimic potential geologic conditions that may occur during long-term radioactive waste storage. The XAS spectra indicate that the uranyl monomer species remain unchanged in most samples, except in those samples that were both coated with an alkylsilane and hydrothermally treated. When the clay was coated with an organic film, formed by the acidic deposition of octadecyltrimethoxysilane, hydrothermal treatment results in the formation of aggregated uranium species in which the uranium is reduced from U{sup VI} to U{sup IV}.

  18. The origin and early genesis of clay bands in youthful sandy soils along lake Michigan, U.S.A.

    Science.gov (United States)

    Berg, R.C.

    1984-01-01

    A beach ridge and dune complex with good radiocarbon control sampling the last 3500 radiocarbon years B.P. provides new insights on the early genesis of clay bands in sandy soils. Soil profiles were sampled by age groups, described in the field, and then subjected to laboratory analyses for particle-size distribution, pH, organic carbon, carbonate minerals, and extractable iron and manganese. This study suggests that small increases in pH, brought about by small increases in carbonate content within the soil profile, are responsible for flocculating small amounts of illuviated clay. This process, along with a transition to a greater hydraulic conductivity with soil depth due to coarser textures in any given profile, partly explains the existence and possible reason for the initiation of illuvial zones and eventually for clay-band horizons. A pronounced increase in the thickness of incipient clay-band horizons in soils older than 2300 years appears due to finer textures in the parent materials than are present in younger soils. Because of slightly reduced porosity and lower permeability, carbonates and a high pH are retained in both illuvial and eluvial horizons of some of these older soils. In addition, only in those profiles older than 2300 years do clay and iron oxide concentrations coincide and is there some suggestion of greater amounts of extractable manganese in horizons of minimum iron and clay. A pronounced segregation of clay-iron bands is not apparent at the study area but should occur in future years as additional amounts of iron and clay are deposited. ?? 1984.

  19. 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

  20. Stereo soft x-ray microscopy and elemental mapping of hematite and clay suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Gleber, S.-C.; Thieme, J.; Chao, W.; Fischer, P.

    2008-09-01

    The spatial arrangements of hematite particles within aqueous soil and clay samples are investigated with soft X-ray microscopy, taking advantage of the elemental contrast at the Fe-L edge around E = 707 eV. In combination with stereo microscopy, information about spatial arrangements are revealed and correlated to electrostatic interactions of the different mixtures. Manipulation of a sample mounted to the microscope is possible and particles added while imaging can be detected.