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

International Nuclear Information System (INIS)

Blanchart, Pascale; Faure, Pierre; Michels, Raymond; Bruggeman, Christophe; De Craen, Mieke; Parant, Stephane

2012-01-01

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

Thermomechanical behaviour of boom clay

International Nuclear Information System (INIS)

Sultan, N.; Delage, P.; Cui, Y.J.

2000-01-01

Special attention has been recently paid on temperature effects on the behaviour of deep saturated clays, in relation with nuclear deep waste storage. However, few experimental data are presently available, and existing constitutive models need to be completed. This note is aimed at completing, both experimentally and theoretically, the understanding of the effects of the over-consolidation ration on the thermal volume changes of Boom clay (Belgium). The experimental data obtained here are in a good agreement with existing data. As a complement to existing data, they are used to develop a new elastoplastic model. The adoption of a second coupled plastic mechanism provides good simulations on a complex thermo-mechanical path. (authors)

Homogeneity vs. Heterogeneity of Porosity in Boom Clay

International Nuclear Information System (INIS)

Hemes, Susanne; Desbois, Guillaume; Urai, Janos L.; De Craen, Mieke; Honty, Miroslav

2013-01-01

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 mm 2 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)

chemo-Hydro-mechanical modelling of in-situ disposal of a bituminized radioactive waste in boom clay

International Nuclear Information System (INIS)

Mokni, N.; Olivella, S.; Valcke, E.; Marien, A.; Smets, S.; Li, X.; Sillen, X.

2012-01-01

Document available in extended abstract form only. The current reference solution of the Belgian Agency for the Management of Radioactive Waste and Fissile Materials (ONDRAF/NIRAS) envisages underground disposal of Eurobitum Bituminized radioactive Waste (BW) in a geologically stable clay formation. In Belgium, the Boom Clay, which is a 30 to 35 million years old and ∼100 m thick marine sediment is being studied as a potential host formation because of its favorable properties to limit and delay the migration of the leached radionuclides to the biosphere over extended periods of time. The current disposal concept foresees that several drums (220 litres) of Eurobitum would be grouped in thick-walled cement-based secondary containers, which in turn would be placed in concrete-lined disposal galleries that are excavated at mid-depth in the clay layer. Only 80-90 % of the total volume of the drum is filled with Eurobitum.The remaining voids between the containers would be backfilled with a cement-based material. The interaction between the BW and the host clay formation is a very complicated chemo-hydro-mechanical process and depends not only on the hydro-mechanical behaviour of the Boom Clay itself, but also on that of the BW. In fact, the osmosis-induced uptake of water by the dehydrated hygroscopic salts embedded in the waste induces a geo-mechanical perturbation of the host formation, caused by the swelling and the increase of the pressure in and around the waste. The objectives of the Chemo-Hydro-Chemical (CHM) analysis presented in this work are (i) to get insights on the kinetics of water uptake by BW, dissolution of the embedded NaNO 3 crystals, solute leaching, and maximum generated pressure under disposal conditions and (ii) to study the stress redistribution due to the recompression of the clay around a gallery caused by the swelling pressure of the bitumen and the admissible swelling pressure for Boom clay. Firstly, a CHM formulation of chemically and

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

International Nuclear Information System (INIS)

Gedeon, M.; Marivoet, J.; Vandersteen, K.

2012-01-01

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

Technetium migration in Boom Clay - Assessing the role of colloid-facilitated transport in a deep clay formation

International Nuclear Information System (INIS)

Bruggeman, C.; Martens, E.; Maes, N.; Jacops, E.; Van Gompel, M.; Van Ravestyn, L.

2010-01-01

Document available in extended abstract form only. The role of colloids - mainly dissolved natural organic matter (NOM, 50-150 mg/l) - in the transport of radionuclides in the Boom Clay formation (Mol, Belgium), has long since been a matter of (heavy) debate. For more than 20 years, batch experiments with Boom Clay suspensions showed a pronounced influence of the dissolved organic carbon concentration on the aqueous concentrations of different radionuclides like Tc, Np, Am and U. Moreover, small fractions of these radionuclides were also observed to elute almost un-retarded out of confined clay cores in percolation experiments. In the past years, a new conceptual model for the speciation of the long-lived fission product Technetium- 99 ( 99 Tc) under Boom Clay conditions has been drafted. In brief, the stable oxidation state of 99 Tc in these conditions is +IV, and, therefore, Tc solution concentrations are limited by the solubility of TcO 2 .nH 2 O(s). However, during reduction of TcVII (in the TcO 4 - form) to TcIV, precursor TcO 2 .nH 2 O colloids are formed, which are stabilised by the dissolved organic matter present in Boom Clay interstitial pore water, and in supernatants of Boom Clay batch suspensions. Moreover, this stabilisation process occurs in such a systematic way, that (conditional) interaction constants could be established, and the behaviour was described as a 'hydrophobic sorption', or, more accurately, a 'colloid-colloid' interaction. This conceptual model was implemented into PHREEQC geochemical and Hydrus transport code to come to a reactive transport model that was used to simulate both the outflow and the tracer profile in several long-term running percolation experiments (both in lab and under in situ conditions). To account for slow dissociation kinetics of Tc from the NOM colloid, a first-order kinetic rate equation was also added to the model. In order to describe the migration of colloidal particles (NOM), an

Mobility of the dissolved organic matter through intact boom clay cores

International Nuclear Information System (INIS)

Put, M.J.; Dierckx, A.; Aertsens, M.; Canniere, P. de

1998-01-01

Performance assessment studies are expected to predict the enhancement of the migration of trivalent lanthanides and actinides due to their complexation with organic matter, which play a role as a transport agent [1]. Therefore, the mobility of the dissolved organic matter in the interstitial boom clay water is studied. For the first time, the mobile fraction present in the clay water is concentrated and labelled with a radioisotope to study the mobility of the organic matter in clay and the interaction of the mobile with the non-mobile. The isotopes tested as label are 125 I and 14 C. The 125 I label proved to be unstable and hence discarded. The labelled organic matter is then diluted for migration experiments on boom clay cores under anaerobic conditions. The influence of the molecular size on its mobility is studied by the separation of the labelled organic matter in different size fractions. (orig.)

Regional modelling of the confined aquifers below the Boom clay in NE-Belgium

International Nuclear Information System (INIS)

Vandersteen, K.; Gedeon, M.; Marivoet, J.; Wouters, L.

2012-01-01

Document available in extended abstract form only. 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, the Boom Clay is considered as a reference host rock for the geological disposal of high-level radioactive waste in NE-Belgium (Campine area). The hydrogeological program at SCK.CEN supports the long-term performance assessments of the geological disposal of radioactive waste by performing a phenomenological research of the aquifer systems surrounding the studied disposal system. One of the important components of this programme is the regional hydrogeological modelling. The regional hydrogeology is studied using two main models - the steady state Neogene aquifer model (NAM) and the transient deep aquifer pumping model (DAP), developed to characterize and quantify the regional groundwater flow in, respectively, the aquifers lying above the Boom Clay in the Nete catchment area (NAM), and the aquifers lying below the Boom Clay in the Campine area (DAP). This paper describes the most recent update of the DAP model. The DAP model represents the confined part of the groundwater system located stratigraphically below the Boom Clay. This includes the parts of the Oligocene aquifer, the Bartoon aquitard system and the Ledo-Paniselian-Brusselian aquifer buried under the Boom Clay. Due to the considerable pumping from these aquifers in combination with a limited recharge, a gradual decrease in groundwater levels has been observed in more than 30-year piezometric records. In the DAP model, the shallow aquifer system overlying the Boom Clay is replaced by fixed head boundaries: this aquifer system is dominated by close-to-surface hydrological processes and the heads fluctuate seasonally without any apparent long-term trend. In the horizontal direction, the model extends to the south as far as the outcrops of the major aquitards: the Maldegem Formation confining the Ledo

Thermo-hydro-mechanical behaviour of Boom clay; Comportement thermo-hydro-mecanique de l'argile de Boom

Energy Technology Data Exchange (ETDEWEB)

Le, T.T

2008-01-15

This thesis studied the thermo-hydro-mechanical properties of Boom clay, which was chosen to be the host material for the radioactive waste disposal in Mol, Belgium. Firstly, the research was concentrated on the soil water retention properties and the hydro-mechanical coupling by carrying out axial compression tests with suction monitoring. The results obtained permitted elaborating a rational experimental procedure for triaxial tests. Secondly, the systems for high pressure triaxial test at controlled temperature were developed to carry out compression, heating, and shearing tests at different temperatures. The obtained results showed clear visco-elasto-plastic behaviour of the soil. This behaviour was modelled by extending the thermo-elasto-plastic model of Cui et al. (2000) to creep effect. (author)

On the role of anisotropy in the perturbation of Boom Clay by a deep disposal repository for high-level wastes

International Nuclear Information System (INIS)

Sillen, X.; Li, X.L.; Van Marcke, P.; Chen, G.; Bastiaens, W.

2010-01-01

Document available in extended abstract form only. All along the characterisation programme of the Boom Clay, a potential host rock for geological disposal of long-lived, heat-emitting radioactive waste, evidences of anisotropy of key thermo-hydro-mechanical (THM) properties have been collected through direct observations and laboratory measurements. In parallel, evidences of anisotropic THM behaviour of the clay massif were obtained during excavations and in-situ experiments in the underground research laboratory HADES at Mol. Careful analysis of the observations and simple modelling reveal the key role of the anisotropy of the material properties and, to a lesser extent, the in situ stresses in the development of a damaged zone around the galleries and the hydro-mechanical perturbation in the clay massif. As a consequence of the sedimentary deposition process, clay formations often exhibit visible bedding. This is the case for Boom Clay. Like other deep clays, Boom Clay also exhibits pronounced strain anisotropy under certain hydro-mechanical loading. Isotropic compression tests performed in the early nineties have shown that, for Boom Clay at a depth of about 225 m, the increments of deformation perpendicular to the bedding planes, i.e. vertical, are about two times larger than increments of deformation parallel to the bedding planes, i.e. horizontal. Moreover, it was observed that this mechanical anisotropy decreases progressively as the isotropic stress is increased. Drained heating tests under constant isotropic loading also evidenced anisotropic behaviour during thermo-consolidation. Like the mechanical properties, hydraulic and thermal properties of the Boom Clay also show anisotropy: lab and in situ measurements suggest that the horizontal hydraulic conductivity is about twice the vertical one while the ratio between horizontal and vertical thermal conductivities is about 1.4. The anisotropic THM behaviour of the Boom Clay was evidenced during excavations

Support to other nuclear waste disposal programmes considering clay as a potential host rock

International Nuclear Information System (INIS)

Volckaert, G.

2009-01-01

SCK-CEN started to study the Boom Clay as potential host rock for nuclear waste disposal in 1974. Since then, SCK-CEN has been involved in other international projects studying clay as potential host rock in order to get a broader support for disposal in clay and to acquire broader insight in clay behaviour. Besides Belgium, France and Switzerland are currently investigating clay formations as potential host rock for the disposal of radioactive waste. In the Netherlands, clay formations have always been considered as an alternative to disposal in salt. The general interest in clays is increasing: in Germany and The United Kingdom, it was decided a few years ago that besides respectively salt and crystalline rock also clays need to be evaluated. In Eastern and Central Europe, the Slovak republic and Lithuania consider both clay and granite as possible host rocks for spent fuel while in Russia recently a project was started to study the possible disposal of low and medium level waste in a clay formation in the Leningrad area. Within the EC research and development framework programs and the OECD/NEA Clay Club, collaborations were developed between countries studying clay and with a strong involvement of SCK-CEN. The collaboration with the Eastern and Central European countries is supported through the support programme of the Belgian Ministry of Economic affairs. The objectives of these co-operations are to deliver expert services to other nuclear waste disposal programs considering clay as host rock; to to acquire broader international recognition of our expertise and support for the development of nuclear waste disposal in clay; to get a broader insight in the properties and behaviour of clays

Radionuclide solubilities in boom clay. Final report, part 2 : a report produced for ONDRAF/NIRAS

International Nuclear Information System (INIS)

Baker, S.; Baston, G.M.N.; Boult, K.A.

2000-01-01

The release of radionuclides from a High Level Radioactive Waste repository situated in the Boom Clay at Mol would depend, in part, on their retardation within the Boom Clay. A number of parameters are required to assess such retardation; these include the solubilities of key radionuclides and their sorption behaviour. ONDRAF/NIRAS has identified neptunium, technetium, selenium, uranium and plutonium as elements for study. AEA Technology plc was requested to undertake a joint experimental and modelling study to determine the solubilities of these five elements under conditions representative of those in the Boom Clay (the in situ chemical conditions are pH∼8, Eh ∼ -230 mV). The work programme was carried out over three years, and for completeness this final report includes all the results

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

International Nuclear Information System (INIS)

Baldi, G.; Hueckel, T.; Peano, A.; Pellegrini, R.

1991-01-01

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

A study on the secondary consolidation of Boom Clay at Essen site under loading and unloading compression

International Nuclear Information System (INIS)

Deng, Y.F.; Cui, Y.J.; Tang, A.M.; Li, X.L.; Sillen, X.

2010-01-01

Document available in extended abstract form only. Boom clay formation, a thick deposit of over-consolidated marine clay has been selected as a possible host material of nuclear waste disposal in Belgium. For this purpose, its deformation behaviour, especially its long-term deformation behaviour (secondary consolidation) is essential for the safety of the whole storage system and therefore needs to be investigated deeply. In the present work, odometer consolidation tests were performed on Boom clay taken from the Essen site. The loading and unloading were run in steps and the secondary consolidation coefficient C α (C α = de/dlogt) was determined for each step. This allows the secondary consolidation behaviour to be analysed. Four soil cores of Boom clay were taken from the site of Essen, Belgium, at the depths of 220-248 m. The geotechnical identification characteristics of these cores are similar: specific gravity, γ s = 2.64-2.68; liquid limit, w L = 68-78%; plastic limit, w P = 29-33%; and plastic index, I P 36-45. The soil water content (w) is between 26.5 and 29.7% and the void ratio (e) between 0.700 and 0.785. The blue methylene values (VBS) are equally similar, VBS = 6.20-6.67 (g/100 g). The clay fraction (< 2 μm) is relatively high (more than 50%). An example of the results obtained is presented (void ratio versus vertical stress and secondary consolidation coefficient versus vertical stress, determined in the e/log t plot) for the core taken at 227 m depth. After the installation of specimen in the odometer cell, an initial loading to the in-situ stress gave rise to a decrease of the void ratio from 0.730 to 0.651. The drainage system was then saturated for the subsequent loading/unloading paths in steps. The results show that the void ratio decreased to 0.270 when the vertical stress reached σ v = 32 MPa. A compression index Cc of about 0.31 can be estimated and the swelling index is estimated at 0.14. C α > 0 during loading and C α < 0 during

Radionuclide solubilities in boom clay. Final report, part 2 : a report produced for ONDRAF/NIRAS

Energy Technology Data Exchange (ETDEWEB)

Baker, S.; Baston, G.M.N.; Boult, K.A. [and others

2000-07-01

The release of radionuclides from a High Level Radioactive Waste repository situated in the Boom Clay at Mol would depend, in part, on their retardation within the Boom Clay. A number of parameters are required to assess such retardation; these include the solubilities of key radionuclides and their sorption behaviour. ONDRAF/NIRAS has identified neptunium, technetium, selenium, uranium and plutonium as elements for study. AEA Technology plc was requested to undertake a joint experimental and modelling study to determine the solubilities of these five elements under conditions representative of those in the Boom Clay (the in situ chemical conditions are pH{approx}8, Eh {approx} -230 mV). The work programme was carried out over three years, and for completeness this final report includes all the results.

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

Science.gov (United States)

Deng, Y. F.; Cui, Y. J.; Tang, A. M.; Nguyen, X. P.; Li, X. L.; Van Geet, M.

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

Studying the migration behaviour of radionuclides in boom clay by electromigration

Energy Technology Data Exchange (ETDEWEB)

Norbert Maes, H.; Moors, H.; Dierckx, A.; Aertsens, M.; Wang, L.; Canniere, P. de; Put, M. [SCK-CEN, Belgian Nuclear Research Centre, Waste and Disposal - R and D Geological Disposal Mol (Belgium)

2001-07-01

Migration studies are an important part in the assessment of the performance of the Boom Clay Formation as a candidate for geological disposal of High-Level radwaste in Belgium. However, classical diffusion experiments take a long time because of the excellent retention characteristics of the Boom Clay. Electrical fields can be used to move ionic species. Especially for low permeability soils/sediments (such as clays), this driving force is far more efficient than a hydraulic gradient. As a consequence, the experimental time can be reduced drastically. This paper gives an overview on the quantitative and qualitative use of electromigration as a powerful technique to study radionuclides migration in clays. The enormous time gain in the determination of migration parameters for strongly retarded radionuclides as {sup 137}Cs{sup +} and {sup 226}Ra{sup 2+} is first demonstrated. Secondly, we want to demonstrate that electromigration has some useful features to study the behaviour of radionuclides with a more complex chemistry like the redox sensitive element uranium and Am-Organic Matter (OM) complexes. In the case of uranium, electromigration provides information on the speciation of the migrating species while for the Am-organic Matter complexes the role of OM as a possible carrier of actinides is investigated. (orig.)

Studying the migration behaviour of radionuclides in boom clay by electromigration

International Nuclear Information System (INIS)

Norbert Maes, H.; Moors, H.; Dierckx, A.; Aertsens, M.; Wang, L.; Canniere, P. de; Put, M.

2001-01-01

Migration studies are an important part in the assessment of the performance of the Boom Clay Formation as a candidate for geological disposal of High-Level radwaste in Belgium. However, classical diffusion experiments take a long time because of the excellent retention characteristics of the Boom Clay. Electrical fields can be used to move ionic species. Especially for low permeability soils/sediments (such as clays), this driving force is far more efficient than a hydraulic gradient. As a consequence, the experimental time can be reduced drastically. This paper gives an overview on the quantitative and qualitative use of electromigration as a powerful technique to study radionuclides migration in clays. The enormous time gain in the determination of migration parameters for strongly retarded radionuclides as 137 Cs + and 226 Ra 2+ is first demonstrated. Secondly, we want to demonstrate that electromigration has some useful features to study the behaviour of radionuclides with a more complex chemistry like the redox sensitive element uranium and Am-Organic Matter (OM) complexes. In the case of uranium, electromigration provides information on the speciation of the migrating species while for the Am-organic Matter complexes the role of OM as a possible carrier of actinides is investigated. (orig.)

Organic matter linked radionuclide transport in Boom clay - Phenomenological understanding and abstraction to PA

International Nuclear Information System (INIS)

Maes, N.; Bruggeman, C.; Liu, D.J.; Salah, S.; Van Laer, L.; Wang, L.; Weetjens, E.; Govaerts, J.; Marivoet, J.; Brassinnes, S.

2012-01-01

Document available in extended abstract form only. In the frame of the Belgian research program on long term management of high-level and/or long-lived radioactive wastes coordinated by ONDRAF/NIRAS, plastic clays (i.e., Boom Clay and Ypresian clays) are investigated for their potential to host a deep geological disposal repository for radioactive waste because of, among others, their ability to significantly retard radionuclide releases to the biosphere. The Boom Clay is characterised by the presence of a relatively high amount of dissolved organic matter (DOM, humic substances) which show a strong interaction with a suite of radionuclides (RN) like lanthanides, actinides and transition metals. This interaction with DOM leads in general to an increased mobility of the radionuclide as the OM can act as a colloidal carrier for the radionuclide. Therefore, the quantification and the understanding of the underlying processes are needed for the demonstration of confidence in the host formation to act as a suitable barrier. However, this is not an easy task, given the multitude of processes involved: complexation/colloid formation, sorption, kinetics, filtration, -. In this presentation, we will provide an overview of the research work that leads to a straightforward reactive transport model capturing fairly well the experimental observations. The model can be considered as an intermediate model providing a good basis for further safety abstraction on the one hand and the way to a more detailed phenomenological understanding on the other hand. The research is focussed on the underlying processes that govern speciation, sorption and transport. These underlying processes are investigated in a bottom-up approach, from simple systems to more complex systems. Interpretation is done using thermodynamic based models. Whereas the contribution of Bruggeman et al. focusses mainly on (batch) sorption studies (of trivalent RN), this presentation will provide more details on the

The experimental testing of the long-term behaviour of cemented radioactive waste from nuclear research reactors in the geological disposal conditions of the boom clay

International Nuclear Information System (INIS)

Sneyers, A.; Marivoet, J.; Iseghem, P. van

1998-01-01

Liquid wastes, resulting from the reprocessing of spent nuclear fuel from the BR-2 Materials Testing Reactor, will be conditioned in a cement matrix at the dedicated cementation facility of UKAEA at Dounreay. In Belgium, the Boom clay formation is studied as a potential host rock for the final geological disposal of cemented research reactor waste. In view of evaluating the safety of disposal, laboratory leach experiments and in situ tests have been performed. Leach experiments in synthetic clay water indicate that the leach rates of calcium and silicium are relatively low compared to those of sodium and potassium. In situ experiments on inactive samples are performed in order to obtain information on the microchemical and mineralogical changes of the cemented waste in contact with the Boom clay. Finally, results from a preliminary performance assessment calculation suggest a non-negligible maximum dose rate of 5 10 -9 Sv/a for 129 I. (author)

The experimental testing of the long-term behaviour of cemented radioactive waste from nuclear research reactors in the geological disposal conditions of the boom clay

Energy Technology Data Exchange (ETDEWEB)

Sneyers, A.; Marivoet, J.; Iseghem, P. van [SCK-CEN, B-2400 Mol (Belgium)

1998-07-01

Liquid wastes, resulting from the reprocessing of spent nuclear fuel from the BR-2 Materials Testing Reactor, will be conditioned in a cement matrix at the dedicated cementation facility of UKAEA at Dounreay. In Belgium, the Boom clay formation is studied as a potential host rock for the final geological disposal of cemented research reactor waste. In view of evaluating the safety of disposal, laboratory leach experiments and in situ tests have been performed. Leach experiments in synthetic clay water indicate that the leach rates of calcium and silicium are relatively low compared to those of sodium and potassium. In situ experiments on inactive samples are performed in order to obtain information on the microchemical and mineralogical changes of the cemented waste in contact with the Boom clay. Finally, results from a preliminary performance assessment calculation suggest a non-negligible maximum dose rate of 5 10{sup -9} Sv/a for {sup 129}I. (author)

Modelling of radionuclide migration and heat transport from an High-Level-Radioactive-Waste-repository (HLW) in Boom clay

International Nuclear Information System (INIS)

Put, M.; Henrion, P.

1992-01-01

For the modelling of the migration of radionuclides in the Boom clay formation, the analytical code MICOF has been updated with a 3-dimensional analytical solution for discrete sources. the MICOF program is used for the calculation of the release of α and β emitters from the HIGH LEVEL RADIOACTIVE WASTES (HLW). A coherent conceptual model is developed which describes all the major physico-chemical phenomena influencing the migration of radionuclides in the Boom clay. The concept of the diffusion accessible porosity is introduced and included in the MICOF code. Different types of migration experiments are described with their advantages and disadvantages. The thermal impact of the HLW disposal in the stratified Boom clay formation has been evaluated by a finite element simulation of the coupled heat and mass transport equation. The results of the simulations show that under certain conditions thermal convection cells may form, but the convective heat transfer in the clay formation is negligible. 6 refs., 19 figs., 2 tabs., 5 appendices

Geotechnical characterization of boom clay in relation to the disposal of radioactive waste

International Nuclear Information System (INIS)

Horseman, S.T.; Winter, M.G.; Enwistle, D.C.

1987-01-01

This report describes the results of a laboratory study on the geotechnical properties of the Tertiary Boom clay. Tests were performed on 'undisturbed' samples of clay taken from a location 247 m below surface at the SCK/CEN experimental site at Mol in Belgium. In geotechnical terms, the Boom clay (at depth) may be described as a hard, high-plasticity, overconsolidated clay. Test methods have included (a) the one-dimensional consolidation test with consolidation stresses up to 32 MPa, (b) the one dimensional swelling pressure test, (c) the isotropically-consolidated, undrained (CIU) triaxial test with pore pressure measurement, and (d) the unconsolidated undrained (UU) triaxial test. All triaxial tests were load-controlled. Limited test results are presented on pore pressure responses during heating under undrained conditions and on the effect of elevated temperature (80 O C) on deformability and strength. It is found that significantly large excess pore pressures (circa 1 MPa under in situ stress conditions) may be developed during heating from ambient laboratory temperature to 80 O C. The effect is due, at least in part, to the expansion of the pore fluid

Design study for a macropermeability test in an argillaceous formation (Boom clay)

International Nuclear Information System (INIS)

Bronders, J.

1992-01-01

In the present report a test design has been developed for determining the in-situ permeability of the Boom clay on a large scale at the Mol site (Belgium). Since in the Boom clay at the Mol site an Underground Repository Facility (URF) is operational the test has been designed to be run in or from this facility. The proposal is an in-situ macropermeability test with a set-up comprising a central borehole (metric scale in length) designed to allow various types of control of the water-level, surrounded by a lattice of piezometers installed in the clay mass for the monitoring of the interstitial water pressure changes in function of the various water-level controls. In one part the report describes the potential set-ups and a theoretical background as far as it can be done on the basis of existing literature and experiments. In a second part the method (technical and practical data of a test set-up) is described and documented. The method proposed is largely based on the several years of expertise gained within the field of in-situ migration and hydrogeologic investigations in the Hades-URF. 14 refs., 9 figs., 2 tabs

Reactive transport modelling of a heating and radiation experiment in the Boom clay (Belgium)

International Nuclear Information System (INIS)

Montenegro, L.; Samper, J.; Delgado, J.

2003-01-01

Most countries around the world consider Deep Geological Repositories (DGR) as the most safe option for the final disposal of high level radioactive waste (HLW). DGR is based on adopting a system of multiple barriers between the HLW and the biosphere. Underground laboratories provide information about the behaviour of these barriers at real conditions. Here we present a reactive transport model for the CERBERUS experiment performed at the HADES underground laboratory at Mol (Belgium) in order to characterize the thermal (T), hydrodynamic (H) and geochemical (G) behaviour of the Boon clay. This experiment is unique because it addresses the combined effect of heat and radiation produced by the storage of HLW in a DGR. Reactive transport models which are solved with CORE, are used to perform quantitative predictions of Boom clay thermo-hydro-geochemical (THG) behaviour. Numerical results indicate that heat and radiation cause a slight oxidation near of the radioactive source, pyrite dissolution, a pH decrease and slight changes in the pore water chemical composition of the Boom clay. (Author) 33 refs

Use of bore logging for the determination of lithological characteristics of the Boom clay formation and interest for correlations in clay

International Nuclear Information System (INIS)

Neerdael, B.; Bonne, A.; Manfroy, P.; Vandenberghe, N.; Fierens, E.; Laga, P.

1981-01-01

It is first recalled that the purpose of the HADES project of the CEN/SCK at Mol (Belgium) is to study the possibility of geological disposal for radioactive wastes in the Boom clay formation at a depth between +-160 and 270 m. The different steps and aspects of the site investigation are exposed, and for each of them, the specific techniques used are reviewed. One of these steps is elaborated more in detail. It covers namely the lateral extrapolation of the lithological variations as established from a very detailed analysis of the initial cored boring. Among the usefull methods, the most practical and refined results were obtained from the resistivity logs in the reconnaissance holes. Finally, examples are shown of very detailed correlation on site scale, scale of the hydrogeological entity and regional scale (occurrence of Boom clay on the belgian territory)

Determination of gas diffusion coefficients in undisturbed Boom clay

International Nuclear Information System (INIS)

Jacops, E.; Volckaert, G.; Maes, N.; Govaerts, J.; Weetjens, E.

2012-01-01

Document available in extended abstract form only. The Belgian agency for radioactive waste and enriched fissile materials Ondraf/Niras presently considers Boom Clay as a potential host formation for the disposal of high-level and long-lived radioactive waste. The production of gas is unavoidable within a geological repository. Gas is produced by different mechanisms: anaerobic corrosion of metals in waste and packaging, radiolysis of water and organic materials in the waste and engineered barriers and microbial degradation of various organic wastes. Corrosion and radiolysis yield mainly hydrogen while microbial degradation leads to methane and carbon dioxide. The gas generated in the near field of a geological repository will dissolve in the pore water and is transported away from the repository by diffusion as dissolved species. If the gas generation rate is larger than the diffusive flux, the pore water will become over-saturated and a free gas phase will form. Initially, isolated gas bubbles will accumulate until a continuous gas phase is formed. As gas pressure continues to increase, discrete gas pathways may be formed by tensile fractures within the rock fabric. Consequently, this entire process may locally and at least temporarily alter the hydraulic and mechanical properties of the engineered barriers and the clay and, perhaps, their performance. Therefore it is important to assess whether or not gas production rates might exceed the diffusive gas flux. The currently available gas diffusion parameters (D eff : effective diffusion coefficient) for hydrogen in Boom Clay, obtained from the MEGAS project, and re-evaluated after lead to an estimated D eff between 1.9 10 -12 and 1.5 10 -10 m 2 /s. Sensitivity calculations showed that this uncertainty on the diffusion coefficient, combined with that on the gas source term, made it impossible to exclude the formation of a free gas phase. To reduce the uncertainty, an experimental method was developed to determine

Study of the Boom clay layer as a geochemical barrier for long-lived radionuclides

International Nuclear Information System (INIS)

Baetsle, L.H.; Henrion, P.; Put, M.; Cremers, A.

1985-01-01

The Boom clay layer below the nuclear site of Mol, Belgium has been thoroughly investigated on its geohydrologic and physicochemical characteristics as well as by laboratory experiments and in situ tests in the underground laboratory. Hydraulic permeabilities have been measured in situ; the chemical composition of the interstitial clay water is related to the mineralogical composition. Radionuclide sorption data and sorption mechanisms are given for Cs, Sr, Eu, Tc, Am, Pu and Np; experimental diffusion coefficients were determined by clay plug migration tests in representative conditions. Results of model calculations for the migration of radionuclides in dense porous media are given for Cs, Sr, Pu and Np

Experimental evaluation of the hydraulic resistance of compacted bentonite/boom clay interface

International Nuclear Information System (INIS)

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

2008-01-01

In the framework of the in-situ PRACLAY Heater experiment to be performed in the HADES URF in Mol (Belgium), the feasibility of a hydraulic cut-off of the Excavation Damaged Zone (EDZ) and the Repository Components (RC) of the disposal galleries by using a horizontal seal will be examined. It has been planned to install an annular seal composed of compacted bentonite between the heated zone and the access gallery (PRACLAY seal test), so that to avoid any hydraulic shortcut towards the access gallery. According to numerical scoping calculations, heating until 80 deg C will induce a pore pressure of the order of 3.0 MPa. In order to verify the effects of this water pressure on the performance of the annular seal system and more specifically on the hydraulic resistance of the interface between the compacted bentonite and the host rock (Boom clay), laboratory percolation tests at 20 and 80 deg C were performed. The results confirm the performance of the compacted bentonite seal to avoid the hydraulic shortcut to the access gallery under the foreseen hydraulic and thermal conditions. (author)

The role of natural organic matter in the migration behaviour of americium in the Boom clay - Part II: analysis of migration experiments

International Nuclear Information System (INIS)

Hicks, T.; Bennett, D.; Maes, N.; Wang, L.; Warwick, P.; Hall, T.; Walker, G.; Dierckx, A.

2005-01-01

Full text of publication follows: In demonstrating the suitability of Boom Clay as a potential site for the disposal of radioactive waste in Belgium, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs investigation. Trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may have opposing effects. If complexed by the aqueous phase (mobile) NOM, radionuclide transport will be governed by the mobility of these dissolved radionuclide-NOM species. If complexed by the solid phase (immobile) NOM, migration will be retarded. One of the aims of the EC projects TRANCOM-Clay and TRANCOM-II was to investigate the role of mobile NOM as radionuclide carrier with the objective of deriving conceptual models that can be implemented in repository performance assessment (PA) models. A separate paper describes the results of column migration experiments involving the transport of 241 Am- 14 C-NOM complexes through Boom Clay cores. This paper describes the transport model, POPCORN, that was developed to describe and evaluate the influence of NOM on radionuclide transport in clay, taking into account attachment/detachment rates of NOM to clay surfaces and the kinetics of RN complexation to, and destabilization from, NOM. The POPCORN model was used to evaluate diffusion experiments involving injection of 14 C-labelled NOM in Boom Clay cores. Model fits were obtained by varying the rates of filtration of NOM by attachment to the surface of the clay matrix. POPCORN was then used to analyse the 241 Am- 14 C-NOM migration experiments. The stability properties of the 241 Am-NOM were characterised by kinetic constants, and good matches to the migration data were achieved for the experiments. The findings suggest that a small sub-population of the original 241 Am-OM is the most stable, and that this

Geomechanical behaviour of boom clay under ambient and elevated temperature conditions

International Nuclear Information System (INIS)

Neerdael, B.; Beaufays, R.; Buyens, M.; Bruyn, D. de; Voet, M.

1992-01-01

This research is focused upon in-situ investigations related to the (thermo-) mechanical behaviour of clay. Three main items are covered in this research area: Stress measurements around the underground research facility for radioactive waste disposal using hydraulical stress monitoring stations; detection of micro-fractures in the clay host, mainly using geophysical seismic techniques; long term mechanical behaviour of clay (this last item, studied by ANDRA at Mol, is not described in this paper). The stress monitoring stations appear to be more reliable in getting relative pressure variations with time rather than absolute values of stress, even after studying and improving the characteristics of the surrounding grout. The seismic techniques used to appear to be sensitive and accurate enough for detecting induced fracturation in the clay host, even for the low temperature. This is also in agreement with bench-scale experiments on clay samples intended to quantify the influence of both temperature and consolidation on the velocity. 10 refs., 80 figs., 3 tabs

Pore-water chemistry effects on the compressibility behaviour of Boom Clay

International Nuclear Information System (INIS)

Deng, Y.F.; Cui, Y.J.; Tang, A.M.; Nguyen, X.P.; Li, X.L.; Maarten, V.G.

2010-01-01

Document available in extended abstract form only. Boom clay is a thick deposit of over-consolidated marine clay, and belongs to the Oligocene series. Its hydraulic conductivity has been investigated since many years in Belgium within the site characterization program related to the performance assessment of potential geological disposal of high-level radioactive waste in this formation. Recently, the work of Wemaere et al. (2008) shows a significant variability of the hydraulic conductivity of the Boom clay. Indeed, they performed measurements on soil cores taken from four distant boreholes at various depths. The vertical hydraulic conductivity was found to vary from 3 x 10 -12 to 10 x 10 -12 m/s. It is suspected that this variability would be partly related to the water chemistry effects. Indeed, De Craen et al. (2006) shows that the pore-water chemical composition of soil cores taken from the Essen site is significantly different from that at the Mol site. If the pore water chemistry has strong effect on the hydraulic conductivity, its effect on the mechanical behaviour needs to be investigated too. The aim of this paper is to verify whether there are significant effects of pore-water chemistry on the soil compressibility. This study would be helpful to transpose the knowledge obtained from the Mol site to other sites of Boom clay formation where the geochemical components are different from the former site, as the hydro-mechanical characteristics of Boom clay at the Mol site has been widely investigated since the last decades. Two soil cores were taken from the Essen site at a depth of 227 m (Ess83) and 240 m (Ess96). Based on the geochemical analysis presented by De Craen et al. (2006), synthetic water having similar chemical composition of the in-situ pore-water was prepared. The identification geotechnical characteristics of these cores are shown in Table 2. It can be observed that the clay content (particle size < 2 μm) is relatively high (more than 50

The CEC benchmark interclay on rheological models for clays results of pilot phase (January-June 1989) about the boom clay at Mol (B)

International Nuclear Information System (INIS)

Come, B.

1990-01-01

A pilot phase of a benchmark exercise for rheological models for boom clay, called interclay, was launched by the CEC in January 1989. The purpose of the benchmark is to compare predictions of calculations made about well-defined rock-mechanical problems, similar to real cases at the Mol facilities, using existing data from laboratory tests on samples. Basically, two approaches were to be compared: one considering clay as an elasto-visco-plastic medium (rock-mechanics approach), and one isolating the role of pore-pressure dissipation (soil-mechanics approach)

Technical feasibility of a concept radioactive waste disposal facility in Boom clay in the Netherlands

International Nuclear Information System (INIS)

Vardon, P.J.; Hicks, M.A.; Fokker, P.A.; Fokkens, J.H.

2012-01-01

Document available in extended abstract form only. The current management strategy in the Netherlands for radioactive waste is interim storage for approximately 100 years, followed by final deep geological disposal. At present, both Boom Clay and Salt formations are being considered and investigated via the OPERA (Onderzoeks Programma Eindberging Radioactief Afval) and CORA (Commissie Opberging Radioactief Afval) research programmes respectively, instigated by COVRA (Centrale Organisatie Voor Radioactief Afval). This paper outlines the on-going investigation into the initial technical feasibility of a high-level radioactive waste disposal facility, located within a stratum of Boom Clay, as part of the OPERA research programme. The feasibility study is based on the current Belgian Super-container concept, incorporating specific features relevant to the Netherlands, including the waste inventory and possible future glaciation. The repository is designed to be situated at approximately 500 m depth in a Boom Clay stratum of approximately 100 m thickness, and will co-host vitrified High Level Waste (HLW), spent fuel from research reactors, non-heat generating HLW, Low and Intermediate Level Waste (LILW) and depleted uranium. The total footprint is designed to be 3050 m by 1300 m, and will be segregated by waste type. The waste will be stored in drifts drilled perpendicular to the main galleries and will vary in length and diameter depending upon waste type. The repository life-cycle can be considered in three phases: (i) the pre-operation phase, including the conceptual development, site investigation and selection, design and construction; (ii) the operational phase, including waste emplacement and any period of time prior to closure; and (iii) the post-operational phase. The research on the technical feasibility of the repository will investigate whether the repository can be constructed and whether it is able to perform the appropriate safety functions and meet

Technetium behaviour in Boom Clay - a laboratory and field study

International Nuclear Information System (INIS)

Baston, G.M.N.; Ilett, D.J.; Cowper, M.M.; Pilkington, N.J.; Tweed, C.J.; Williams, S.J.; Canniere, P.R. de; Wang, L.

2002-01-01

This paper describes a study of technetium solubility and migration under chemical conditions representative of those prevailing in a Boom Clay environment. Laboratory and in situ measurements yielded similar aqueous concentrations of technetium, of about 1 x 10 -8 mol dm -3 , close to the concentrations measured for hydrated technetium(IV) oxide TcO 2 .1.6H 2 O in the solubility studies. From fitting the curves of the Tc concentrations as function of time, distribution coefficient (K d ) values were estimated to lie between 0.8 cm 3 g -1 and 1.8 cm 3 g -1 . Exposure of the system at 80 C and to γ-radiation dose rates of several hundred Gy h -1 resulted in only minor differences in behaviour. (orig.)

First assessment of the pore water composition of Rupel Clay in the Netherlands and the characterisation of its reactive solids

NARCIS (Netherlands)

Behrends, T.; Veen, I. van der; Hoving, A.; Griffioen, J.

2016-01-01

The Rupel Clay member in the Netherlands largely corresponds to the Boom Formation in Belgium, and this marine, clay-rich deposit is a potential candidate to host radioactive waste disposal facilities. Prediction of the speciation of radionuclides in Rupel Clay pore water and their retardation by

Calibration of mathematical models for simulation of thermal, seepage and mechanical behaviour of boom clay

International Nuclear Information System (INIS)

Baldi, G.; Borsetto, M.; Hueckel, T.

1987-01-01

This report presents results of research on the verification of the validity of a generalized thermo-elastoplastic-hydraulic mathematical model elaborated at Ismes for description of the behaviour of boom clay. The model is described in Section 2. Experimental results performed at Ismes for the identification of the material constants in athermal and thermal drained conditions are then presented. Procedures for the identification are described in Section 4. The undrained consolidated constant total stress heating test is then discussed. The undrained test shows the possibility of clay yielding due to effective pressure decrease during heating, caused by water pressure growth. The test has been simulated numerically, confirming the interpretation of the experiment. Further simulation of plane strain and plane stress central heating axisymmetric problem shows again a formation of a yielded clay zone around the heater. Interpretation of the results and recommendations for further research are given

Geo-scientific characterisation of the Boom Clay in the Netherlands in light of permanent confinement of radio-active waste

NARCIS (Netherlands)

Griffioen, J.J.; Simmelink, E.; Westerhoff, W.; Koenen, M.; Tambach, T.; Behrends, T.

2012-01-01

Recently, the OPERA research program has been initiated in the Netherlands. Its central objective is to develop initial, conditional safety cases for repositories in the Boom Clay and Zechstein rocksalt formations. TNO Geological Survey of the Netherlands has been granted two projects that deal with

R and D programme on radioactive waste disposal into geological formations (study of a clay formation)

International Nuclear Information System (INIS)

Centre d'Etude de l'Energie Nucleaire, Mol

1987-01-01

This report deals with the R and D activities performed by the Belgian Nuclear Research Establishment (SCK/CEN) and its subcontractors concerning the disposal of high-level and long-life conditioned wastes in a deep clay formation, the Boom clay. The studies reported concern equally experimental as theoretical work spread over the following research issues: geochemical characterization of the Boom clay, modelling of radionuclide migration in the clay environment, irradiation effects and corrosion behaviour of candidate canister materials in the Boom clay, geomechanical, construction, backfilling and sealing studies related to underground facilities, regional hydrological investigations of the Mol site and safety and risk analysis. The geomechanical and construction-related studies are to a large extent focused on in situ research, performed along the construction of the underground Hades laboratory. The corrosion studies are also dealing with the preparation of in situ experiments in the same underground laboratory. These various research issues are meant to contribute to the assessment of the technical feasibility and safety of the geological disposal in an argillaceous host formation

On the oxidation of the dissolved organic matter in Boom clay by NaNO3 and NaNO2 from disposed Eurobitum bituminized waste

International Nuclear Information System (INIS)

Vasile, M.; Bleyen, N.; Valcke, E.; Bruggeman, C.; Marien, A.

2012-01-01

Document available in extended abstract form only. In Belgium, Boom Clay is studied as a potential host clay formation for the final disposal of EUROBITUM bituminized waste, which consists of 60 wt% hard bitumen (Mexphalt R85/40) and 40 wt% waste. The main salts that are present in the bituminized waste are NaNO 3 , 20-30 wt%, and CaSO 4 , 4-6 wt%. After disposal of the waste in the clay, an uptake of pore water by the embedded, dehydrated and hygroscopic salts will lead to a swelling of the waste and to a release of the salts into the Boom Clay. A possible consequence of the salt release is the oxidation of the clay by nitrate and, possibly, nitrite, resulting in a lower reducing capacity of the clay towards redox sensitive radionuclides, which in turn could have an impact on the migration behaviour of these radionuclides. The extent of oxidation of authigenic Boom Clay redox sensitive components, like organic matter and pyrite is studied at the SCK.CEN. As a first step in the study of the influence of nitrate and nitrite on the redoxactive Boom Clay components, we performed batch tests with dissolved organic matter (DOM). DOM was exposed to different concentrations of nitrate and nitrite for more than one year in both biotic and abiotic conditions. This paper will discuss the results obtained by exposing DOM to nitrate and nitrite and comparing two methods for the determination of its redox capacity. NaNO 3 or NaNO 2 , previously stored under inert atmosphere to remove all oxygen gas, was added to Boom Clay water collected from a piezometer to obtain final salt concentrations of 0.1 and 0.005 M NaNO 3 , or 0.05 and 0.005 M NaNO 2 . Sodium azide, also stored under inert atmosphere, was added (0.2 wt. %) to inhibit the microbial activity in the tests, creating abiotic conditions. All solutions were prepared in an anaerobic glove box. The nitrate and nitrite reduction by DOM was followed by analysing the concentrations of nitrate, nitrite and ammonium in the

Technetium behaviour in Boom Clay - a laboratory and field study

Energy Technology Data Exchange (ETDEWEB)

Baston, G.M.N.; Ilett, D.J.; Cowper, M.M.; Pilkington, N.J.; Tweed, C.J.; Williams, S.J. [AEA Technology plc, Harwell, Didcot, Oxfordshire (United Kingdom); Canniere, P.R. de; Wang, L. [SCK.CEN, Waste and Disposal Project, Boeretang, Mol (Belgium)

2002-07-01

This paper describes a study of technetium solubility and migration under chemical conditions representative of those prevailing in a Boom Clay environment. Laboratory and in situ measurements yielded similar aqueous concentrations of technetium, of about 1 x 10{sup -8} mol dm{sup -3}, close to the concentrations measured for hydrated technetium(IV) oxide TcO{sub 2}.1.6H{sub 2}O in the solubility studies. From fitting the curves of the Tc concentrations as function of time, distribution coefficient (K{sub d}) values were estimated to lie between 0.8 cm{sup 3} g{sup -1} and 1.8 cm{sup 3} g{sup -1}. Exposure of the system at 80 C and to {gamma}-radiation dose rates of several hundred Gy h{sup -1} resulted in only minor differences in behaviour. (orig.)

A method for the determination of gas diffusion coefficients in undisturbed Boom Clay

International Nuclear Information System (INIS)

Jacops, E.; Volckaert, G.; Maes, N.; Weetjens, E.; Maes, T.; Vandervoort, F.

2010-01-01

Document available in extended abstract form only. The main mechanisms by which gas will be generated in deep geological repositories are: anaerobic corrosion of metals in wastes and packaging; radiolysis of water and organic materials in the packages, and microbial degradation of various organic wastes. Corrosion and radiolysis yield mainly hydrogen while microbial degradation leads to methane and carbon dioxide. The gas generated in the near field of a geological repository in clay will dissolve in the ground water and be transported away from the repository by diffusion as dissolved species. However if the gas generation rate is larger than the diffusive flux, the pore water will get over-saturated and a free gas phase will be formed. This will lead to a gas pressure build-up and finally to an advective gas flux. The latter might influence the performance of the repository. Therefore it is important to assess whether or not gas production rates can exceed the capacity of the near field to store and dissipate these gases by dissolution and diffusion only. The current available gas diffusion parameters for hydrogen in Boom Clay, obtained from the MEGAS project, suffer from an uncertainty of 1 to 2 orders of magnitude. Sensitivity calculations performed by Weetjens et al. (2006) for the disposal of vitrified high-level waste showed that with this uncertainty on the diffusion coefficient, the formation of a free gas phase cannot be excluded. Furthermore, recent re-evaluations of the MEGAS experiments by Krooss (2008) and Aertsens (2008) showed that the applied technique does not allow precise determination of the diffusion coefficient. Therefore a new method was developed to determine more precisely the gas diffusion coefficient for dissolved gases (especially dissolved hydrogen) in Boom Clay. This should allow for a more realistic assessment of the gas flux evolution of a repository as function of the estimated gas generation rates. The basic idea is to perform a

Study of the chemo-hydro-mechanical behavior of stiff clays in the context of radioactive waste disposal

International Nuclear Information System (INIS)

Nguyen, Xuan Phu

2013-01-01

The present research aims to understand the chemo-hydro-mechanical behavior of stiff clays through two geological formations, the Boom Clay and the Ypresian clays which are considered as possible host formations for the radioactive wastes disposal in Belgium. The volume change behavior was studied in both intact and reconstituted states, and under different conditions: under K0 and isotropic loading, under loading/unloading loops. The results show that the volume change behavior is governed by the competition between the physico-chemical effect and the mechanical effect, characterized by a threshold stress which corresponds to the swelling stress in terms of structure changes. A constitutive law was developed to capture this aspect. The permeability was determined, compared with the results in literature and correlated with the parameters as void ratio. The permeability variation with depth shows the important role of macro-pores in fluids' transfer. The volume change behavior and permeability of intact Boom Clay and Ypresian clays are also influenced by pore water chemical composition changes which modify the diffuse double layer and give rise to the aggregation of clay particles. The elastic parameters, yield curve and failure envelope of Boom Clay and Ypresian clays were identified. A conceptual elasto-plastic model was developed, accounting for the swelling effects and the competition between the physico-chemical effect and the mechanical effect. (author)

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

International Nuclear Information System (INIS)

Alonso, E. E.; Alcoverro, J.

1999-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Alonso, E E; Alcoverro, J

1999-07-01

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

Disposal of radioactive waste into clay layers the most natural option

International Nuclear Information System (INIS)

Baetsle, L.H.; Bonne, A.

1990-01-01

Among the geological formations suitable for the disposal of radioactive waste, the clay formations provide outstanding opportunities : impermeable for water, self-healing, strongly absorbing for ions, widespread in nature. The self-healing properties of large clay deposits have been demonstrated by their auto-sealing and plastic response to tectonic stress and magmatic intrusion. The discovery of fossil trees preserved after geologic periods of burial in clay is one of the most dramatic illustrations of their entombment ability. The physicochemical and hydrologic characteristics of the Boom clay are very favorable for the confinement of migrating radionuclides within the layer. Except for the extremely long half-lives ( 237 Np, 129 I,...) no radionuclide can escape from the clay body. The effects of heat, metal corrosion, material interaction and biochemical degradation on the natural properties of the clay layer are discussed in some detail and related to the natural properties of the clay formation which have to stay unaltered for geologic periods. The first Safety Assessment Report, established by NIRAS-ONDRAF in close collaboration with SCK-CEN, has been submitted to a multi-disciplinary task force which is to advise the Belgian Government on the suitability of the Boom clay layer below the Nuclear Research site of Mol as a potential host formation for nuclear waste coming from the electronuclear program. 13 refs., 2 figs., 1 tab

Construction of an underground facility for ''in-situ'' experimentation in the boom clay

International Nuclear Information System (INIS)

Bonne, A.; Manfroy, P.; Van Haelewijn, R.; Heremans, R.

1985-01-01

The Belgian R and D Programme concerning the disposal of high-level and alpha-bearing radioactive waste in continental geological formations was launched by SCK/CEN, Mol in 1974. The programme is characterised by its site and formation specific approach, i.e. Mol and Boom clay. In the framework of site confirmation, an important issue is the ''in situ'' experimentation which should allow to determine with a higher degree of confidence the numerical value of the data needed for the evaluations, assessments and designs. The present report deals with the construction of an underground experimental facility, which was scheduled to be fully completed in mid 1984. Initially, the completion was scheduled for the end of 1983, but supplementary experiments related to geomechanics and mining capabilities and to be performed during the construction phase of the experimental facility delayed the completion of the underground facility. During the construction, a continuous observation was made of the behaviour of the clay mass and the structures. In this final contract-report, only the as-built structure, the time schedule and the ''in situ'' experiments launched or performed during the construction phase are dealt with

Multi-technical approach to characterize the dissolved organic matter from clay-stone

International Nuclear Information System (INIS)

Blanchart, Pascale; Michels, Raymond; Faure, Pierre; Parant, Stephane; Bruggeman, Christophe; De Craen, Mieke

2012-01-01

Document available in extended abstract form only. Currently, different clay formations (Boom Clay, Callovo-Oxfordian argilites, Opalinus Clay, Toarcian shales...) are studied as reference host rocks for methodological studies on the geological disposal of high-level and long-lived radioactive waste. While a significant effort is being done on the characterization of the mineral composition and the reactivity of the clays as barriers, the occurrence of organic matter, even in low proportion cannot be neglected. The organic matter appears as gas (C 1 -C 4 as identified in the Bure underground facilities), as solid (kerogen), as hydrocarbon liquids (free hydrocarbons within the kerogen or adsorbed on minerals) as well as in the aqueous phase (Dissolved Organic Matter - DOM). DOM raises specific interest, as it may have complexation properties towards metals and rare earth elements and is potentially mobile. Therefore, it is important to characterize the DOM as part of a study of feasibility of geological disposal. In this study, four host rocks were studied: - The Callovo-Oxfordian shales of Bure Underground Research Laboratory (Meuse, France); - The Opalinus Clay of Mont Terri Underground Research Laboratory (Switzerland); - The Toarcian shales of Tournemire (Aveyron, France); - The Boom Clay formation studied in The HADES Underground Research Laboratory (Mol, Belgium). Organic matter characteristics vary upon formation in terms of (i) origin (mainly marine type II; mixtures of marine type II and higher plants type III organic matter often poorly preserved), (ii) TOC contents, (iii) thermal maturity (for instance, Opalinus Clay and Toarcian shales are more mature and have poor oxygen content compare to Callovo-Oxfordian shales and Boom Clay). These differences in organic matter quality may have an influence on the quantity and the quality of DOM. The DOM of the rocks was isolated by Soxhlet extraction using pure water. A quantitative and qualitative multi

Clay shale as host rock. A geomechanical contribution about Opalinus clay

International Nuclear Information System (INIS)

Lempp, Christof; Menezes, Flora; Sachwitz, Simon

2016-01-01

The Opalinuston is a prominent rock representing the type of organic clay shales or clay stones within the sequence of Triassic and Jurassic marine sediments in Southern Germany. The rock forms a homogenous unit some ten meters thick. The degree of consolidation of this type of pelitic rock depends mainly on the former load conditions, but is also dependent on the long-term weathering and even on the present exposition. The geomechanical parameters such as shear strength, tensional strength and permeability vary with the state of consolidation and become important when the use is discussed of such rocks for radioactive waste disposal. A tunneling project at the northern escarpment of the Swabian Alb (Southwest Germany) within the Opalinus clay offered the rare opportunity to obtain fresh unweathered rock samples in greater amounts compared to fresh drilling cores from which geomechanical investigations are usually undertaken. Consequently, the results of geomechanical laboratory testings are presented in order to compare here the results of multistep triaxial compression tests, of hydraulic fracturing laboratory tests and of some other tests for rock characterization with the corresponding results of Opalinus clay sites in Switzerland that were investigated by the Swiss Nagra Company for host rock characterization. After a discussion of the relevant state of fresh Opalinus clay, especially of suction pressure conditions and saturation state, the results of triaxial shear tests are presented. Increasing shear deformation at increasing pressure and unchanged water saturation do not result in a significant strength reduction of the Opalinus clay. The rock shows increasing cohesion and stiffness, if multiple loading has repeatedly reached the failure point. Thus there is no increased permeability with continued shearing. Only at the beginning of the shearing process is a temporarily increased permeability to be expected due to dilatation processes. An increased

A new coupled elastoplastic damage model for clay-stone and its parameter identification

International Nuclear Information System (INIS)

Jia, S.P.; Chen, W.Z.; Yu, H.D.; Li, X.L.; Sillen, X.

2010-01-01

Document available in extended abstract form only. In Belgium, the Boom Clay is considered as a potential host rock for the geological disposal of the high level nuclear waste and is intensively studied from hydro-mechanical point of view. Laboratory tests on Boom clay shown that the Boom clay presents very complex stress strain behaviour. Undrained triaxial tests indicated often a hardening behaviour at small deformation and softening at larger deformation. It is not easy to give an explicit function to describe the stress-strain behaviour under triaxial stress state. The mechanical characteristics are obviously affected by the porosity, fractures growth, water content, and stress, etc., four stages can be usually distinguished from the stress-strain curve of Boom Clay, named as OA, AB, BC and CD. 1) Stage OA, the relation between stress and strain is linear. This stage is elastic state, and point A is called as yield strength σ c0 . 2) Stage AB, the weak fractures in the rock appear, develop and cumulate gradually. Point B is called peak strength σ cu . 3) Stage BC, peak strength is reached and stress reduces with the increasing of strain, up to the residual strength. This stage is called strain softening and point C is the residual strength σ cr . The axial pressure causes the fracture developing and strength reducing. 4) Stage CD, the final strength doesn't reduce obviously with the development of plastic deformation. This stage is called plastic flow. Obviously, The conventional elasto-plastic constitutive model can not describe the mechanical behaviours of Boom Clay. Based on damage mechanics theory, an new elasto-plastic damage constitutive model is put forward and applied to Boom Clay, which can describe the complex stress-strain behaviour of clay. It is described as follows: stage OA with an elastic model, stage AB with elastic damage model, stage BC and stage CD with plastic damage model. The complete process curve of stress-strain can be divided

Study of the 'Clay of Boom' with regard to the storage of nuclear waste. Appendices; Onderzoek Klei van Boom in verband met eventuele opslag kernafval. Bijlagen

Energy Technology Data Exchange (ETDEWEB)

Brugge, J.V.M.; Vrouwe, B.J. [T and A Survey, Amsterdam (Netherlands)

2011-01-15

The Dutch government aims to store nuclear waste in the Dutch soil. Geological research organization T and A Survey mapped the areas that match with the demands of the Dutch government regarding underground storage of nuclear waste. These are areas in which the Clay layer of Boom has a minimal thickness of 100 meters and the depth of the top of the clay formation is at least 500 meters. This report contains the appendices with (geological) maps and data. [Dutch] De Nederlandse overheid wil kernafval ondergronds opslaan in de Nederlandse bodem. Geologisch onderzoeksbureau T and A Survey brengt de gebieden in kaart, die voldoen aan de door de overheid gestelde eisen voor mogelijke ondergrondse opslag van kernafval. Het gaat om gebieden waar de Boomse kleilaag een minimale dikte van 100 meter heeft en de diepte van de top van de kleiformatie minimaal 500 meter bedraagt. Dit rapport bevat de bijlagen met (geologische) kaarten en gegevens.

A consistent phenomenological model for natural organic matter linked migration of Cm(III), Pu(III/IV), Np(IV), Tc(IV) and Pa(V) in the Boom Clay

International Nuclear Information System (INIS)

Martens, E.; Maes, N.; Bruggeman, C.; Van Gompel, M.

2010-01-01

Document available in extended abstract form only. As Natural Organic Matter (NOM) may modify/enhance the mobility of radionuclides (RNs) through complexation or colloidal interactions, it is essential to evaluate the impact of these processes before performing safety assessments aiming at demonstrating the suitability of deep-seated clayey formations for geological disposal of radioactive waste. Column migration experiments with Cm, Pu, Np, Tc and Pa in Boom Clay, initiated about 10 years ago, showed strikingly similar features despite their different chemical speciation. On a relative short time, these RNs began percolating through the clay core until a constant concentration at the outlet side was reached. As most of the aqueous forms of these RNs are supposed to sorb strongly onto the Boom Clay solid phase, it was assumed that their relative fast transport was due to colloids (either intrinsic colloids or NOM-colloids). The constant concentration percolating from the core was thought to result from a solubility limiting phase precipitated at the source position. However, the concentrations in the percolate were systematically lower than the thermodynamic calculated solubilities, and all the more, complexation to NOM would likely result in an increased RN concentration. Although these curves could be modelled by a simple diffusion-advection relationship with linear sorption, they could not be backed up by a mechanistic understanding. As the concentration in the percolate remained constant for many years, the RN-species eluting from the core are assumed to be well in equilibrium with the Boom Clay geochemical conditions. Therefore, they were used as input source (constant concentration boundary condition) for a migration experiment through a fresh clay core (i.e. the outlet of a first cell was coupled to the inlet of a second cell). The measured concentrations at the outlet of the second clay core also reached a constant value, but this value is about one order

Geochemical characterisation of kerogen from the Boom Clay Formation (Mol, Belgium) and evolution under different thermal stress

International Nuclear Information System (INIS)

Deniau, I.

2002-12-01

The Boom clay formation in Belgium has been chosen as test site for the disposal of high level radioactive wastes. The organic matter present in the clay (kerogen) is sensible to the thermal stress and can generate a huge number of gaseous and liquid compounds leading to local pH changes and to fracturing processes. In particular, some polar compounds can complex radionuclides. The samples analyzed in this work were taken in the underground laboratory of Mol at a 223 m depth. They have been analyzed in detail using geochemical methods (Rock-Eval pyrolysis, element analysis, transmission and scanning electron microscopy), spectroscopic methods (Fourier transformation infrared spectroscopy, solid state 13 C NMR, Raman) and pyrolytic methods (off-line, on-line and in sealed tubes combined with coupled CG/SM analyses). The study of a representative sample of this formation has permitted to characterize the organic matter at the molecular scale, to determine its fossilization mechanisms and the nature of the organic compounds trapped inside the kerogen. The organic matter of the Boom clays comes mainly from phyto-planktonic matter with an important contribution of terrestrial and bacterial matter. The degradation-recondensation played an important role in its preservation but the presence of numerous oxygenated molecules implies that oxidative incorporation also participated to this preservation. Finally, various products (hydrocarbons, oxygenated and nitrogenous polar compounds) trapped in significant amount inside the macro-molecular structure are released under a relatively weak thermal stress. Moreover several small polar organic molecules are released and can play a significant role in the retention or migration of radionuclides inside the geologic barrier. A sample submitted to a in-situ thermal stress of 80 deg. C during 5 years (Cerberus experiment) do not show any significant change in its kerogen structure with respect to the non-heated reference sample

Air oxidation and biodegradation of the organic matter from the Boom Claycomparison between artificial and natural altered series

International Nuclear Information System (INIS)

Blanchart, Pascale; Faure, Pierre; Michels, Raymond; Bruggeman, Christophe; De Craen, Mieke

2010-01-01

Document available in extended abstract form only. The Boom Clay formation (Belgium) is studied as the reference host rock for methodological studies on the geological disposal of high-level and long-lived radioactive waste. The drilling of galleries in the Boom Clay at Mol lead to the perturbation of the initial physical and chemical conditions. Since organic matter is present in this argillaceous formation, it is important to know its response to these new conditions. The Boom Clay is of Tertiary age (Rupelian) and has a TOC content up to 5%. Its pore water (20% in mass of rock) contains significant quantities of Dissolved Organic Carbon (DOC) with a mean concentration of 115+/-15 mg/L, determined on the basis of piezometer water as well as squeezing and leaching experiments. Yet, in piezometers, the DOC may show considerable and irregular variations through time, with values ranging between 80 and 425 mg/L. The origin and bio-physico-chemical controls of such variations are yet unknown. Perturbation of the in-situ conditions of the clay is a possible reason for such observation. More likely the introduction of air as well as micro-organisms may have an impact that needs to be estimated. Well-preserved, freshly-drilled Boom Clay samples, as well as samples of different degrees of alteration (air exposed clay from the older galleries) were collected with the aim of determining and quantifying different molecular markers representative for the alteration degree. Additionally, increasing artificial air oxidation experiments were carried out on fresh Praclay samples (sampled during the PRACLAY gallery excavation) in order to obtain an altered reference series. Moreover PRACLAY samples previously extracted with an organic solvent (dichloromethane) were also prepared in order to identify the influence of the kerogen during oxidation. In these experiments, powdered clay was heated at 80 deg. C under air flow during 1, 3, 6, 9, 12, 18 months. Organic matter composition

Thermo-hydraulic behaviour of Boom Clay using a heating cell. experimental and numerical study

International Nuclear Information System (INIS)

Lima, A.; Romero, E.; Vaunat, J.; Gens, A.; Li, X.L.

2010-01-01

Document available in extended abstract form only. Boom clay is the subject of extensive research in Belgium dealing with all phenomena that may possibly affect the performance of this geological formation as potential radioactive waste repository. Specifically, thermal loads may play an important role on this low-permeability clay. There are a number of laboratory results concerning the saturated hydro-mechanical behaviour of Boom clay under different temperatures and recent studies on this area are described in Le (2008). Nevertheless, information on clay hydro-mechanical response on heating and cooling paths under small-scale laboratory conditions is less known. To this aim, non-isothermal tests on intact borehole samples were carried out using an axisymmetric heating cell described in Munoz et al. (2009). Heating and cooling paths under nearly constant volume and different target temperatures (maximum 85 deg. C) were performed under controlled hydraulic boundary conditions. The paper presents results of an exhaustive experimental programme performed on a fully-instrumented cell (sample 75 mm in diameter and 100 mm high) with a controlled-power heater installed along the axis of the sample. Different transducers were monitoring the sample response: two miniature pore water pressure transducers located at different heights of the lateral wall of the cell, three thermocouples (two at equivalent locations in relation to the pressure transducers and one near the heater), and top and lateral strain gauges attached to reduced thickness sections of the walls. The cell has top and bottom valves to apply the hydraulic conditions. The protocol of the tests presented three important phases: hydration, heating and cooling. Throughout the heating and cooling phases, the bottom drainage was maintained open at a constant water pressure of 1 MPa using an automatic pressure/volume controller, while the upper valve was kept closed. This back-pressure was important since it

Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

Energy Technology Data Exchange (ETDEWEB)

Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

2011-06-20

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

International Nuclear Information System (INIS)

Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

2011-01-01

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

Report of a study on the characteristics of the 'Clay of Boom' that are relevant in considering this clay layer package for the storage of nuclear waste; Rapportage van onderzoek aan eigenschappen van de Klei van Boom die relevant zijn bij de beschouwing van dit laagpakket voor opslag van kernafval

Energy Technology Data Exchange (ETDEWEB)

Brugge, J.V.M.; Vrouwe, B.J. [T and A Survey, Amsterdam (Netherlands)

2010-12-15

The Dutch government aims to store nuclear waste in the Dutch soil. Geological research organization T and A Survey mapped the areas that match with the demands of the Dutch government regarding underground storage of nuclear waste. These are areas in which the Clay layer of Boom has a minimal thickness of 100 meters and the depth of the top of the clay formation is at least 500 meters. [Dutch] De Nederlandse overheid wil kernafval ondergronds opslaan in de Nederlandse bodem. Geologisch onderzoeksbureau T and A Survey brengt de gebieden in kaart, die voldoen aan de door de overheid gestelde eisen voor mogelijke ondergrondse opslag van kernafval. Het gaat om gebieden waar de Boomse kleilaag een minimale dikte van 100 meter heeft en de diepte van de top van de kleiformatie minimaal 500 meter bedraagt.

The long-term behaviour of cemented research reactor waste under the geological disposal conditions of the Boom Clay Formation: results from leach experiments

International Nuclear Information System (INIS)

Sneyers, A.; Fays, J.; Iseghem, P. van

2001-01-01

The Belgian Nuclear Research Centre SCK-CEN has carried out a number of studies to evaluate the long-term behaviour of cemented research reactor waste under the geological disposal conditions of the Boom Clay Formation. Static leach experiments in synthetic clay water were performed on active samples of cemented research reactor waste. The leach experiments were carried out under anaerobic conditions at two testing temperatures (23 and 85 o C). Leach rates of seven radionuclides ( 60 Co, 90 Sr, 134 Cs, 137 Cs, 144 Ce, 154 Eu and 241 Am) were measured. Most investigated radionuclides are well retained within the cement matrix over a 280 days testing period. Results on the source term of radionuclides were complemented with data on the leaching behaviour of cement matrix constituents as Ca, Si, Al, Na, K, Mg and SO 4 as well as with data from performance assessment calculations and in situ tests. Despite limitations inherent to short-term experiments, combined results from these investigations indicate only limited interactions of disposed research reactor waste with the near field of a geological repository in clay. (author)

Time extrapolation aspects in the performance assessment of high and medium level radioactive waste disposal in the Boom Clay at Mol (Belgium)

International Nuclear Information System (INIS)

Volckaert, G.

2000-01-01

SCK-CEN is studying the disposal of high and long-lived medium level waste in the Boom Clay at Mol, Belgium. In the performance assessment for such a repository time extrapolation is an inherent problem due to the extremely long half-life of some important radionuclides. To increase the confidence in these time extrapolations SCK-CEN applies a combination of different experimental and modelling approaches including laboratory and in situ experiments, natural analogue studies, deterministic (or mechanistic) models and stochastical models. An overview is given of these approaches and some examples of applications to the different repository system components are given. (author)

Repository tunnel construction in deep clay formations

International Nuclear Information System (INIS)

Clarke, B.G.; Mair, R.J.; Taylor, R.N.

1992-01-01

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

Water-cooled, fire boom blanket, test and evaluation for system prototype development

International Nuclear Information System (INIS)

Stahovec, J. G.; Urban, R. W.

1999-01-01

Initial development of actively cooled fire booms indicated that water-cooled barriers could withstand direct oil fire for several hours with little damage if cooling water were continuously supplied. Despite these early promising developments, it was realized that to build reliable full-scale system for Navy host salvage booms would require several development tests and lengthy evaluations. In this experiment several types of water-cooled fire blankets were tested at the Oil and Hazardous Materials Simulated Test Tank (OHMSETT). After the burn test the blankets were inspected for damage and additional tests were conducted to determine handling characteristics for deployment, recovery, cleaning and maintenance. Test results showed that water-cooled fire boom blankets can be used on conventional offshore oil containment booms to extend their use for controlling large floating-oil marine fires. Results also demonstrated the importance of using thermoset rubber coated fabrics in the host boom to maintain sufficient reserve seam strength at elevated temperatures. The suitability of passively cooled covers should be investigated to protect equipment and boom from indirect fire exposure. 1 ref., 2 tabs., 8 figs

Modification of booming level for higher correlation with booming sensation; Booming level no koseidoka

Energy Technology Data Exchange (ETDEWEB)

Hatano, S; Hashimoto, T [Seikei University, Tokyo (Japan)

1997-10-01

In our previous study, we proposed a objective measure, i.e., Booming Level for quantifying booming sensation caused by car interior noise. In this paper, Booming Level was modified with its weighting function and within the process of calculation 1/3 octave band level was modified for the best match with subjective result. These modifications were conducted through a subjective experiment rating booming sensation with sounds having much lower frequency contents below 63Hz. With this modified Booming Level, we have obtained higher correlation for rating booming sensation with sounds having prominent low frequency components. 1 ref., 10 figs.

The effect of clay on the dissolution of nuclear waste glass

Science.gov (United States)

Lemmens, K.

2001-09-01

In a nuclear waste repository, the waste glass can interact with metals, backfill materials (if present) and natural host rock. Of the various host rocks considered, clays are often reported to delay the onset of the apparent glass saturation, where the glass dissolution rate becomes very small. This effect is ascribed to the sorption of silica or other glass components on the clay. This can have two consequences: (1) the decrease of the silica concentration in solution increases the driving force for further dissolution of glass silica, and (2) the transfer of relatively insoluble glass components (mainly silica) from the glass surface to the clay makes the alteration layer less protective. In recent literature, the latter explanation has gained credibility. The impact of the environmental materials on the glass surface layers is however not well understood. Although the glass dissolution can initially be enhanced by clay, there are arguments to assume that it will decrease to very low values after a long time. Whether this will indeed be the case, depends on the fate of the released glass components in the clay. If they are sorbed on specific sites, it is likely that saturation of the clay will occur. If however the released glass components are removed by precipitation (growth of pre-existing or new secondary phases), saturation of the clay is less likely, and the process can continue until exhaustion of one of the system components. There are indications that the latter mechanism can occur for varying glass compositions in Boom Clay and FoCa clay. If sorption or precipitation prevents the formation of protective surface layers, the glass dissolution can in principle proceed at a high rate. High silica concentrations are assumed to decrease the dissolution rate (by a solution saturation effect or by the impact on the properties of the glass alteration layer). In glass corrosion tests at high clay concentrations, silica concentrations are, however, often higher

The effect of clay on the dissolution of nuclear waste glass

International Nuclear Information System (INIS)

Lemmens, K.

2001-01-01

In a nuclear waste repository, the waste glass can interact with metals, backfill materials (if present) and natural host rock. Of the various host rocks considered, clays are often reported to delay the onset of the apparent glass saturation, where the glass dissolution rate becomes very small. This effect is ascribed to the sorption of silica or other glass components on the clay. This can have two consequences: (1) the decrease of the silica concentration in solution increases the driving force for further dissolution of glass silica, and (2) the transfer of relatively insoluble glass components (mainly silica) from the glass surface to the clay makes the alteration layer less protective. In recent literature, the latter explanation has gained credibility. The impact of the environmental materials on the glass surface layers is however not well understood. Although the glass dissolution can initially be enhanced by clay, there are arguments to assume that it will decrease to very low values after a long time. Whether this will indeed be the case, depends on the fate of the released glass components in the clay. If they are sorbed on specific sites, it is likely that saturation of the clay will occur. If however the released glass components are removed by precipitation (growth of pre-existing or new secondary phases), saturation of the clay is less likely, and the process can continue until exhaustion of one of the system components. There are indications that the latter mechanism can occur for varying glass compositions in Boom Clay and FoCa clay. If sorption or precipitation prevents the formation of protective surface layers, the glass dissolution can in principle proceed at a high rate. High silica concentrations are assumed to decrease the dissolution rate (by a solution saturation effect or by the impact on the properties of the glass alteration layer). In glass corrosion tests at high clay concentrations, silica concentrations are, however, often higher

Focusing on clay formation as host media of HLW geological disposal in China

International Nuclear Information System (INIS)

Zheng Hualing; Chen Shi; Sun Donghui

2007-01-01

Host medium is vitally important for safety for HLW geological disposal. Chinese HLW disposal effort in the past decades were mainly focused on granite formation. However, the granite formation has fatal disadvantage for HLW geological disposal. This paper reviews experiences gained and lessons learned in the international community and analyzes key factors affecting the site selection. It is recommended that clay formation should be taken into consideration and additional effort should be made before decision making of host media of HLW disposal in China. (authors)

Clay shale as host rock. A geomechanical contribution about Opalinus clay; Tonstein als Wirtsgestein. Ein geomechanischer Beitrag ueber Opalinuston

Energy Technology Data Exchange (ETDEWEB)

Lempp, Christof; Menezes, Flora; Sachwitz, Simon [Halle-Wittenberg Univ., Halle (Saale) (Germany). Inst. fuer Geowissenschaften und Geographie

2016-12-15

The Opalinuston is a prominent rock representing the type of organic clay shales or clay stones within the sequence of Triassic and Jurassic marine sediments in Southern Germany. The rock forms a homogenous unit some ten meters thick. The degree of consolidation of this type of pelitic rock depends mainly on the former load conditions, but is also dependent on the long-term weathering and even on the present exposition. The geomechanical parameters such as shear strength, tensional strength and permeability vary with the state of consolidation and become important when the use is discussed of such rocks for radioactive waste disposal. A tunneling project at the northern escarpment of the Swabian Alb (Southwest Germany) within the Opalinus clay offered the rare opportunity to obtain fresh unweathered rock samples in greater amounts compared to fresh drilling cores from which geomechanical investigations are usually undertaken. Consequently, the results of geomechanical laboratory testings are presented in order to compare here the results of multistep triaxial compression tests, of hydraulic fracturing laboratory tests and of some other tests for rock characterization with the corresponding results of Opalinus clay sites in Switzerland that were investigated by the Swiss Nagra Company for host rock characterization. After a discussion of the relevant state of fresh Opalinus clay, especially of suction pressure conditions and saturation state, the results of triaxial shear tests are presented. Increasing shear deformation at increasing pressure and unchanged water saturation do not result in a significant strength reduction of the Opalinus clay. The rock shows increasing cohesion and stiffness, if multiple loading has repeatedly reached the failure point. Thus there is no increased permeability with continued shearing. Only at the beginning of the shearing process is a temporarily increased permeability to be expected due to dilatation processes. An increased

Study of delayed behaviour of clays in deep geologic formations

International Nuclear Information System (INIS)

Rousset, G.; Bazargan, B.; Ouvry, J.F.; Bouilleau, M.

1993-01-01

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

Chemo-hydro-mechanical behaviour of unsaturated clays

International Nuclear Information System (INIS)

Mokni, N.; Olivella, S.; Alonso, E.E.; Romero, E.

2010-01-01

Document available in extended abstract form only. Understanding of the chemical effects on clays is essential for many problems ranging from pollution studies and waste-containment. Several studies examined the effect of changes in pore fluid composition on the mechanical and hydraulic properties. Volume changes (contraction/ expansion) have been measured on clay specimens upon exposure to salt solutions or permeation with organic liquids. Moreover, it was shown that permeation of clay with brine induces an increase of the shear strength. In addition, several models have been proposed to describe the chemo-mechanical behaviour of saturated clays under saturated conditions. A new chemo-hydro-mechanical model for unsaturated clays is under development. The chemo-mechanical effects are described within an elasto-plastic framework using the concept that chemical effects act on the plastic properties by increasing or decreasing the pre-consolidation stress. The model is based on the distinction within the material of a microstructural and a macro-structural levels. Chemical loading has a significant effect on the microstructure. The negative pressure associated with the capillary water plays its role in the interconnected macro pores. By adopting simple assumptions concerning the coupling between the two levels it is intended to reproduce the features of the behaviour of unsaturated clays when there is a change in pore fluid composition (increase or decrease of concentration). A yield surface which defines the set of yield pre-consolidation stress values, for each associated capillary suction and concentration of pore fluid should be defined. In addition, the behaviour of clays under unsaturated condition and the behaviour at full saturation under chemical loading represent two limiting cases of the framework. Studies on the compatibility of Boom Clay with large amounts of nitrate- bearing bituminized radioactive waste have recently raised a particular interest on the

Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

Energy Technology Data Exchange (ETDEWEB)

Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

2010-08-31

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

Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

International Nuclear Information System (INIS)

Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

2010-01-01

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

Thermal volume changes in clays and clay-stones

International Nuclear Information System (INIS)

Delage, P.; Sulem, J.; Mohajerani, M.; Tang, A.M.; Monfared, M.

2012-01-01

Document available in extended abstract form only. The disposal of high activity exothermic radioactive waste at great depth in clay host rocks will induce a temperature elevation that has been investigated in various underground research laboratories in Belgium, France and Switzerland through in-situ tests. Thermal effects are better known in clays (in particular Boom clay) than in clay-stone (e.g. Opalinus clay and Callovo-Oxfordian clay-stone). In terms of volume changes, Figure 1 confirms the findings of Hueckel and Baldi (1990) that volume changes depend on the over-consolidation ratio (OCR) of the clay. In drained conditions, normally consolidated clays exhibit plastic contraction when heated, whereas over-consolidated clay exhibit elastic dilation. The nature of thermal volume changes in heated clays obviously has a significant effect on thermally induced pore pressures, when drainage is not instantaneous like what occurs in-situ. Compared to clays, the thermal volume change behaviour of clay-stones is less well known than that of clays. clay-stone are a priori suspected to behave like over-consolidated clays. In this paper, a comparison of recent results obtained in the laboratory on the drained thermal volume changes of clay-stones is presented and discussed. It is difficult to run drained mechanical tests in clay-stones like the Opalinus clay and the Callovo-Oxfordian clay-stone because of their quite low permeability (10 -12 - 10 -13 m/s). This also holds true for thermal tests. Due to the significant difference in thermal expansion coefficient between minerals and water, it is necessary to adopt very slow heating rate (0.5 - 1 C/h) to avoid any thermal pressurization. To do so, a new hollow cylinder apparatus (100 mm external diameter, 60 mm internal diameter) with lateral drainages reducing the drainage length to half the sample thickness (10 mm) has been developed (Monfared et al. 2011). The results of a drained cyclic thermal test carried out on

Geochemical of clay formations : study of Spanish clay REFERENCE

International Nuclear Information System (INIS)

Turrero, M. J.; Pena, J.

2003-01-01

Clay rocks are investigated in different international research programs in order to assess its feasibility for the disposal of high level radioactive wastes. This is because different sepcific aspects: they have low hydraulic conductivity (10''-11-10''-15 m/s), a high sorption capacity, self-sealing capacity of facults and discontinuities and mechanical resistance. Several research programs on clay formations are aimed to study the chemistry of the groundwater and the water-rock reactions that control it: e. g. Boom Clay (Mol, Belgium), Oxford Clay /Harwell, United Kingdom), Toarcian Clay (Tournemire, France), Palfris formation (Wellenberg, Switzerland), Opalinus Clay (Bure, France). Based on these studies, considerable progress in the development of techniques for hydrologic, geochemical and hydrogeochemical characterization of mudstones has been accomplished (e. g. Beaufais et al. 1994, De Windt el al. 1998. Thury and Bossart 1999, Sacchi and Michelot 2000) with important advances in the knowledge of geochemical process in these materials (e. g. Reeder et al. 1993, Baeyens and Brandbury 1994, Beaucaire et al. 2000, Pearson et al., 2003).Furtermore, geochemical modeling is commonly used to simulate the evolution of water chemistry and to understand quantitatively the processes controlling the groundwater chemistry (e. g. Pearson et al. 1998, Tempel and Harrison 2000, Arcos et al., 2001). The work presented here is part of a research program funded by Enresa in the context of its R and D program. It is focused on the characterization of a clay formation (reference Argillaceous Formation, RAF) located within the Duero Basin (north-centralSpain). The characterisation of th ephysical properties,, fluid composition, mineralogy, water-rock reaction processes, geochemical modelling and sorption properties of the clays from the mentioned wells is the main purpose of this work. (Author)

Experimental study on the thermo-mechanical behaviour of stiff clay under non-isotropic stress state

International Nuclear Information System (INIS)

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

2012-01-01

Document available in extended abstract form only. Stiff clay is usually considered as possible host-rock for geological radioactive waste disposal due to its low permeability and its self-sealing capacity. Boom Clay, for instance, is one of the clays currently considered by the Belgian radioactive waste management agency Ondraf/Niras as a potential host for a geological repository. In order to analyse the performance of this material, it is important to understand its behaviour under the coupled thermo-hydro-mechanical solicitations. In laboratory, several studies have been performed to study the volume change of clay under coupled thermomechanical loading. The results show that heating under drained conditions can induce thermal dilation at low confining stress and thermal contraction at high confining stress. On the other hand, compression tests performed at constant temperature show that the compressibility parameters of soil can be modified by temperature change. These features are now well considered in constitutive laws based on the framework of elasto-plasticity. Under undrained conditions, heating can increase pore-water pressure and this behaviour can be simulated using the theoretical thermo-poro-elastic framework. The temperature effect on the soil behaviour under triaxial compression is also often considered. It is commonly accepted that heating decreases the shear strength of clay but this softening can be hidden by the thermal contraction that occurs during heating which can induce at the same time soil hardening. In spite of these existing works, laboratory tests considering the thermo-mechanical loading path that the soil can be subjected to are still rare. Actually, in the case of geological radioactive waste disposal, after the installation of waste canisters, the soil is expected to be heated under non-isotropic stress state. Most of the existing laboratory works show heating tests in odometer cell or triaxial cell under isotropic stress

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

International Nuclear Information System (INIS)

Heremans, R.

1984-01-01

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

Self-sealing of excavation induced fractures in clay host rock

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chun-Liang [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Braunschweig (Germany)

2015-07-01

Excavation of an underground repository for disposal of radioactive waste in clay formations generates fractures around the openings, which may act as pathways for water transport and radionuclides migration. Because of the favorable properties of the clay rocks such as the rheological deformability and swelling capability, a recovery process of the excavation damaged zone (EDZ) can be expected due to the combined impact of rock compression, backfill resistance, and clay swelling during the post-closure phase. Another important issue is the impact of gases produced from anoxic corrosion of waste containers and other metallic components within the repository. The EDZ may act as a conduit for preferential gas flow, depending on the extent of the recovery process. For the safety assessment of a repository, the self-sealing behaviour and impact on water and gas transport through the EDZ have to be characterized, understood, and predicted. Recently, GRS has extensively investigated these important issues with various kinds of laboratory and in- situ experiments under relevant repository conditions. Test samples were taken from the Callovo-Oxfordian argillite at Bure in France and the Opalinus clay (shaly facies) at Mont Terri in Switzerland. Major findings are summarized as follows. As observed in laboratory and in-situ, the gas permeabilities of the claystones increase with stress-induced damage by several orders of magnitude from the impermeable state up to high levels of 10{sup -12}-10{sup -13} m{sup 2}. When hydrostatic confining stress is applied and increased, the fractures in the claystones tend to close up, leading to a decrease in gas permeability down to different levels of 10{sup -16}-10{sup -21} m{sup 2} at stresses in a range of 10 to 20 MPa. As water enters and flows through fractures, the clay matrix can take up a great amount of the water and expand into the interstices. Consequently, the hydraulic conductivity decreases dramatically by several orders of

Geochemical porosity values obtained in core samples from different clay-rocks

International Nuclear Information System (INIS)

Fernandez, A.M.

2010-01-01

Document available in extended abstract form only. Argillaceous formations of low permeability are considered in many countries as potential host rocks for the disposal of high level radioactive wastes (HLRW). In order to determine their suitability for waste disposal, evaluations of the hydro-geochemistry and transport mechanisms from such geologic formations to the biosphere must be undertaken. One of the key questions about radionuclide diffusion and retention is to know the chemistry and chemical reactions and sorption processes that will occur in the rock and their effects on radionuclide mobility. In this context, the knowledge of the pore water chemistry is essential for performance assessment purposes. This information allows to establish a reliable model for the main water-rock interactions, which control the physico-chemical parameters and the chemistry of the major elements of the system. An important issue in order to model the pore water chemistry in clayey media is to determine the respective volume accessible to cations and anions, i.e, the amount of water actually available for chemical reactions/solute transport. This amount is usually referred as accessible porosity or geochemical porosity. By using the anion inventories, i.e. the anion content obtained from aqueous leaching, and assuming that all Cl - , Br - and SO4 2- leached in the aqueous extracts originates from pore water, the concentration of a conservative ion can be converted into the real pore water concentration if the accessible porosity is known. In this work, the accessible porosity or geochemical porosity has been determined in core samples belonging to four different formations: Boom Clay from Hades URL (Belgium, BE), Opalinus Clay from Mont Terri (Switzerland, CH), and Callovo-Oxfordian argillite from Bure URL (France, FR). The geochemical or chloride porosity was defined as the ratio between the pore water volume containing Cl-bearing pore water and the total volume of a sample

Behavior of clay exposed to heating

International Nuclear Information System (INIS)

Heremans, R.; Buyens, M.; Manfroy, P.

1978-01-01

In the frame of his R and D programme on geological burial of solidified radioactive waste, the C.E.N./S.C.K. undertook experimental and theoretical work on the behavior of the Boom clay against heat. The work is performed under contract with the Commission of European Communities. In a first phase a series of chemical and physical properties were determined on clay samples taken at various depths during the core boring performed on the C.E.N./S.C.K. site in 1975. In a second phase, a simulated high level waste heat source was developed and tested in view of representative heat transfer experiments into the geological formation. In parallel to the experimental work, computarized theoretical studies were undertaken aiming an evaluation of heat effect of a vitrified high level waste repository on an underground structure in clay

Mechanical behavior of galleries in deep clay - Study of a concrete example

International Nuclear Information System (INIS)

Rousset, G.; Jehan, R.A.; Bonne, A.; Fernique, J.C.

1985-01-01

At important depths such as those envisaged for the construction of a radioactive waste disposal, clay appears to be a material of rather weak resistance. One of the first problems to be studied is the technical feasibility of a disposal facility. The time-dependent and strain-softening behavior of the clay plays a significant role in the long term stability of the lined galleries. The in-situ measurements carried out during the digging of a gallery in Boom clay (Belgium), under a 250 m overburden are presented. The data obtained are analyzed by means of an elastoviscoplastic model including strain softening behavior of the clay

Microbiologically mediated processes in a repository sited in a clay host rock

International Nuclear Information System (INIS)

Schwyn, B.; Leupin, O. X.; Bagnoud, A.; Bernier-Latmani, R.

2012-01-01

Document available in extended abstract form only. Because of their favourable retention properties for radionuclides, clay-rich sediments are being considered in Switzerland as host rocks for the geological disposal of high, intermediate- and low-level radioactive waste. Compacted bentonite is foreseen as backfill material in the high level waste repository whereas for intermediate- and low-level waste the near field will mainly consist of cementitious material. The evolution of both types of repositories, which includes re-saturation, heat generation (only high level waste), near field degradation, gas production and radionuclide release may be impacted by microbial activity and vice versa. In this respect questions arise such as: - Are microorganisms present in a repository and its host rock? - Under which condition are microorganisms active in and around a repository? - In which processes are microorganisms involved? Various in situ experiments in a wide range of geological environments have evidenced the presence of microorganisms. Whether the microorganisms found in these in situ experiments are indigenous or introduced by drilling or/and excavation activities is still controversial. However, recent findings suggest the presence of indigenous microorganisms in Opalinus Clay. To conclusively answer the question about the origin of microorganisms, an international investigation programme has been launched to probe rock samples from the Underground Rock Laboratory at Mont Terri. So far, no metabolic activity has been observed in undisturbed clay rocks. Such activity may have ceased during diagenetic compaction of the sediment as suggested by the pore water composition measured in the Callovian-Oxfordian clayey formation of Bure (France). For the safety case of a repository the origin of microorganisms is of minor importance compared to the understanding of the conditions under which they might be metabolically active. Pore size distribution and connectivity can

Étude des interactions mécaniques et physico-chimiques entre les argiles et les fluides de forage. Application à l'argile de Boom (Belgique A Study O the Mechanical and Physicochemical Interactions Between the Clay Materials and the Drilling Fluids. Application to the Boom Clay (Belgium

Directory of Open Access Journals (Sweden)

Tshibangu J. P.

2006-11-01

diffusivity law (20, and if we neglect the influence the concentration of the species s on the diffusion of the species r, assumption which is generally admitted (Put et al, 1987, 1991, we obtain a diffusivity law (21 known as Fick's law. In that equation Lr is the apparent diffusion coefficient which depends on the accessible porosity, on the density and on other factors as expressed in equations (22 and (23. The clay material and the experimental systemThe Boom clay materialWe have chosen the experimentally well known Boom clay material from Belgium in order to study the mechanisms of ions diffusion and/or osmotic transport. This is a gray clay rich in pyrite concretions and septaria, almost homogeneous in the middle part of the geological formation and more silty in lower band and in the upper part with rhythmic changes in silt content. This material from marine depositional environment contains 60% of clay minerals. The 100 m thick geological formation has a burial depth of about 200 m at Mol where a nuclear research center is installed Centre d'études de I'énergie nucléaire (CEN-Mol. Many known characteristics of the Boom clay are given in paragraph 3. 1 : mineralogical composition, geochemical parameters, petrophysical and hydraulic parameters, geomechanical parameters. Two cores were provided graciously by the CEN-Mol and appendices 1 to 4 show some scanner images. It clearly seems when observing these images that the material is heterogeneous on the X-rays point of view, and we think that the more absorbent regions are pyrite concretions. This material is very sensitive to the atmospheric conditions and reacts with oxygen to give a sodium sulphate pore water type whereas the original pore water is of sodium bicarbonate type. To minimize the influence of atmospheric conditions, the time delay has to be minimized between opening of the core and loading of the sample in the experimental system. Four samples were prepared, two of dimensions 40 x 80 mm for a triaxial

Booming Sand Dunes

Science.gov (United States)

Vriend, Nathalie

"Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

Pulse heating tests on two reference Belgian clay formations. Laboratory experiments and numerical study

International Nuclear Information System (INIS)

Lima, A.; Romero, E.; Vaunat, J.; Gens, A.; Li, X.L.

2012-01-01

Document available in extended abstract form only. Two deep clay formations are being investigated in Belgium in connection with the design of a repository for 'High-Level Radioactive Waste': Boom clay at Mol (located between 160 and 270 m depths), considered the reference host formation, and Ypresian clay at Kallo (located between 300 and 450 m depths) as an alternative one. Thermal impact may play an important role on the behaviour of these low-permeability clayey formations. In this context, heating pulse tests on intact borehole samples retrieved in vertical and horizontal directions were carried out on both clays using an axisymmetric heating cell. Heating tests under nearly constant volume conditions and different target temperatures (maximum 85 C) were performed under controlled hydraulic boundary conditions. Attention is focused on the time evolution of temperature and pore water pressure changes during heating and cooling paths -i.e., pore pressure build-up during quasi-undrained heating and later dissipation to the applied hydraulic boundary conditions-. The finite element program CODE-BRIGHT was used to determine thermal parameters by back-analysis and to simulate the experimental results. Table 1 summarises the main properties of these clays. The experimental programme was carried out on a fully-instrumented cell (sample 75 mm diameter and 100 mm high) with a controlled-power heater housed inside the cell. Two miniature pore water pressure transducers located at different heights of the lateral wall of the cell and three thermocouples were used to monitor the sample response. The cell has top and bottom valves to control hydraulic conditions. The protocol of the tests included three main phases: hydration, heating and cooling. Throughout the heating and cooling phases, the bottom drainage was maintained open at a constant water pressure using an automatic pressure/volume controller, while the upper valve was kept closed. Figures 1a and 1c show the time

Interaction between clay-based shaft seal components and crystalline host rock

International Nuclear Information System (INIS)

Priyanto, D.; Dixon, D.; Man, A.

2010-01-01

Document available in extended abstract form only. The Government of Canada has accepted the Nuclear Waste Management Organization's (NWMO) recommendation of Adaptive Phased Management (APM) as the long-term management approach for Canada's used nuclear fuel. APM ultimately involves the isolation and containment of used nuclear fuel deep in a Deep Geological Repository (DGR). On completion of waste emplacement operation and during repository closure, shaft seals, comprising clay-based shaft seal components, will be installed at strategic locations, such as where significant fracture zones (FZs) are located. The primary function of a shaft seal is to limit and prevent short-circuiting of the groundwater flow regime via the shaft. Currently, at Atomic Energy of Canada Limited's Underground Research Laboratory (URL) a full-scale shaft seal is being constructed at the intersection of a low dipping thrust fault called FZ 2 as part of the overall URL decommissioning activities. Both crystalline rock and sedimentary rock are considered potentially suitable host rocks formations for a DGR. This paper presents the results of numerical simulation of a shaft seal installed in moderately to sparsely fractured crystalline rock (MFR). The shape and thickness of the shaft seal modelled for a DGR in this exercise are similar to the shaft seal at the URL, but in the modelling exercise it is given a larger diameter (i.e. 7.30 m) equal to the assumed diameter of a production shaft of a repository. The seal consists of a blended bentonite-sand (BS) component that is constrained between two massive concrete seals. Dense backfill (DBF) materials are installed above and below the concrete seals (CS). The concrete seals are keyed into the access shaft to better anchor the concrete units in place and in order to restrain the swelling of the bentonite-sand component of the seal as it hydrates. The reference geosphere in the proposed work is MFR similar to the rock conditions

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

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)

Alonso, E. E.; Alcoverro, J.

1999-01-01

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

X-Boom, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed X-Boom is an innovation on rollable boom design directly relevant to NASA SBIR topic H5.01, Deployable Structures. The X-boom is a rollable Carbon Fiber...

Coupled thermo–hydro–mechanical processes for the Dutch radioactive waste repository

NARCIS (Netherlands)

Buragohain, P.; Vardon, P.J.; Hicks, M.A.; Vardon, P.J.; Bykov, D.

2016-01-01

Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the Boom Clay is considered as a potential host rock when designing a generic waste repository in the

Modelling the excavation damaged zone using a hydro-mechanical double-scale model

NARCIS (Netherlands)

van den Eijnden, A.P.; Bésuelle, P.; Collin, F.; Chambon, R.; Desrues, J.; Vardon, P.J.; Bykov, D.

2016-01-01

Disposal of spent nuclear fuel and long lived radioactive waste in deep clay geological formations is one of the promising options worldwide. In this concept of the geological disposal system, the Boom Clay is considered as a potential host rock when designing a generic waste repository in the

Chemical buffering capacity of clay rock

International Nuclear Information System (INIS)

Beaucaire, C.; Pearson, F.J.; Gautschi, A.

2004-01-01

The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

Measurement techniques for in situ stresses around underground constructions in a deep clay formation

Directory of Open Access Journals (Sweden)

Li X.L.

2010-06-01

Full Text Available Disposal in deep underground geological formations is internationally recognized as the most viable option for the long-term management of high-level radioactive waste. In Belgium, the Boom clay formation is extensively studied in this context, in particular at the 225 m deep HADES Underground Research Facility in Mol. A cost-effective design of deep underground structures requires an accurate assessment of the in situ stresses; a good estimation of these stresses is also essential when interpreting in situ experiments regarding the hydro-mechanical behaviour of the host formation. Different measurement techniques are available to provide data on the stress evolution and other mechanical properties of the geological formation. The measurement can be direct (measurement of total pressure, or it can be an indirect technique, deriving the stress from related quantities such as strain (changes in structural members. Most total stress measurements are performed through permanently installed sensors; also once-only measurements are performed through specific methods (e.g. pressuremeter. Direct measurement of the stress state is challenging due to the complex mechanical behaviour of the clay, and the fact that the sensor installation inevitably disturbs the original stress field. This paper describes ways to deal with these problems and presents the results obtained using different techniques at HADES.

Experience acquired with the realisation of a geotechnical measurement campaign in a deep clay formation

International Nuclear Information System (INIS)

Manfroy, P.; Neerdael, B.; Buyens, M.

1985-01-01

Belgium has selected clay as a possible disposal medium for conditioned radioactive waste. CEN/SCK has launched an important research and development programme to evaluate the disposal potential of the Boom clay formation present under the nuclear site Mol-Dessel. An underground facility has been built at 220 m. depth in order to proceed to geomechanical, corrosion, migration and heat transfer experiments. During its construction numerous geotechnical measuring instruments were emplaced on the lining and in the clay medium. Successful realization of such measurement campaigns was hampered by the very difficult underground working conditions. This paper describes what can be learned from the experience gained so far. 5 refs.; 5 figs

Realism Assessment of Sonic Boom Simulators

Science.gov (United States)

Sullivan, Brenda M.; Davies, Patrica; Hodgdon, Kthleen K.; Salamone, Joseph A., III; Pilon, Anthony

2008-01-01

Developments in small supersonic aircraft design are predicted to result in low-intensity sonic booms. Booms generated by current aircraft are similar to those that led to the ban on commercial supersonic fli ght over the US, so are unsuitable for parametric studies of psychoac oustic response to low-intensity booms. Therefore, simulators have be en used to study the impact of predicted low-intensity sonic booms. H owever, simulators have been criticized because, when simulating conv entional-level booms, the sounds were observed to be unrealistic by p eople experienced in listening to sonic booms. Thus, two studies were conducted to measure the perceived realism of three sonic boom simul ators. Experienced listeners rated the realism of conventional sonic boom signatures when played in these simulators. The effects on percei ved realism of factors such as duration of post-boom noise, exclusion of very low frequency components, inclusion of ground reflections, a nd type of simulator were examined. Duration of post-boom noise was f ound to have a strong effect on perceived realism, while type of simu lator had a weak effect. It was determined that post-boom noise had t o be at least 1.5 seconds long for the sound to be rated very realist ic. Loudness level did not affect realism for the range of sounds pla yed in the tests (80-93 dB ASEL).

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

International Nuclear Information System (INIS)

Bourke, P.J.; Jefferies, N.L.; Lineham, T.R.; Nesirky, P.

1991-01-01

Two investigations have been undertaken in this programme. The principal investigation was at Culham Laboratory, England, where water flow within the Kimmeridge clay was measured. A subsidiary investigation at SCK/CEN was undertaken at the Underground Research Laboratory 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. These difficulties caused significant disturbance to the Boom clay which was to be tested. Nevertheless the laboratory test proved the feasibility of the experiment. The field measurements at Culham Laboratory, Oxfordshire, were completed with the flow testing of a very silty clay horizon in the Kimmeridge clay. This layer was proved to be laterally continuous after drilling three exploratory boreholes. The hydraulic conductivity of the layer was ≥ 10 -8 ms -1 and comparative tests in the clay showed the conductivity of the clay to be at least 50 times less. 12 figs

Preparation of the PRACLAY demonstration and confirmation experiments: construction of the PRACLAY gallery

International Nuclear Information System (INIS)

Bastiaens, W.

2009-01-01

The PRACLAY demonstration and confirmation experiments contribute to the Belgian research, development and demonstration programme to assess the safety and feasibility of geological disposal of radioactive waste in Boom Clay. Within this programme, the large scale PRACLAY heater experiment aims to verify that Boom Clay is suitable to host heat emitting radioactive waste. A 35 m long section of an experimental gallery in the underground research facility HADES (at 225 m depth) will be heated up to 95 degrees Celsius during ten years. The heater experiment focuses on the response of the host rock to the thermal load. The figure below shows the experimental lay-out. In 2007, an important milestone was reached with the realisation of the PRACLAY gallery (45 m long, external diameter 2.5 m)

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

International Nuclear Information System (INIS)

2013-01-01

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

Corrosion behaviour of carbon steel in the Tournemire clay

International Nuclear Information System (INIS)

Foct, F.; Dridi, W.; Cabrera, J.; Savoye, S.

2004-01-01

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

Structural analysis of oil containment booms

International Nuclear Information System (INIS)

Badesha, S.S.; Hunt, J.; Wenck, E.

1993-01-01

In recent years, major oil spills, such as the Exxon Valdez incident, and many smaller spills have given rise to a worldwide marine environmental concern. One of the most successful devices for containing and facilitating the recovery of spilled oil, and one which does not endanger or alter the environment in any way, is the oil containment boom. Described in this paper is a finite element (FE)-based method for structural analysis of oil booms. In general, a number of FE models for a typical oil boom section are set up using the COSMOS FEA code. These models differ from one another in oil boom geometry, deployment configurations, and oil boom components. The FEA (fimite element analysis) models are made from the plate elements (skirt and tube), truss elements (tension members and ballast chain), and beam elements (end connector). Loads due to tow/current velocity, wind velocity, wave action, and ballasting, as determined from aero/hydrodynamics analysis, are applied as distributed pressures on the plate and beam elements. This method will predict boom tensile load strength, detailed stress distribution, and distortion characteristics for a particular boom with specific deployment configuration and environmental condition. The derived information can be used to highlight critical design features, thereby optimizing the oil boom design. Alternatively, this information can be used for the selection of an oil boom suited for a particular application and, more importantly, can provide the user with a control evaluation tool to determine whether a given oil boom design can withstand the stresses of its intended application

Reactive transport simulations of the evolution of a cementitious repository in clay-rich host rocks

Science.gov (United States)

Kosakowski, Georg; Berner, Urs; Kulik, Dmitrii A.

2010-05-01

that the clay mineral is represented by a X- '(solute) ligand' initially occupied with e.g. Na+. Our representation of cation exchange is based on a multi end-member ideal solid solution model for the clay which at the same time considers the chemical reactivity of the clay phase in the high pH cement environment. As a first application, we will present the results of calculations of the interaction between a cement compartment in contact with a clay-rich host rock. References: Bradbury, M. & Baeyens, B. (2002). Porewater chemistry in compacted re-saturated MX-80 bentonite: Physico-chemical characterisation and geochemical modelling. PSI-Report 02-10, Paul Scherrer Institut, Villigen, Switzerland. Lothenbach, B. & Wieland, E. (2006). A thermodynamic approach to the hydration of sulphate-resisting Portland cement. Waste Management, 26, 706-719. Shao, H., Dmytrieva, S.V., Kolditz, O., Kulik, D.A., Pfingsten, W. & Kosakowski, G. (2009). Modeling reactive transport in non-ideal aqueous-solid solution system. Applied Geochemistry, 24(7), 1287-1300.

High-Quality Seismic Observations of Sonic Booms

Science.gov (United States)

Wurman, Gilead; Haering, Edward A., Jr.; Price, Michael J.

2011-01-01

The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on Earthquake Warning Systems in order to prevent such systems from experiencing false alarms due to sonic booms. The airspace above the Antelope Valley, California includes the High Altitude Supersonic Corridor and the Black Mountain Supersonic Corridor. These corridors are among the few places in the US where supersonic flight is permitted, and sonic booms are commonplace in the Antelope Valley. One result of this project is a rich dataset of high-quality accelerometer records of sonic booms which can shed light on the interaction between these atmospheric phenomena and the solid earth. Nearly 100 sonic booms were recorded with low-noise triaxial MEMS accelerometers recording 1000 samples per second. The sonic booms had peak overpressures ranging up to approximately 10 psf and were recorded in three flight series in 2010 and 2011. Each boom was recorded with up to four accelerometers in various array configurations up to 100 meter baseline lengths, both in the built environment and the free field. All sonic booms were also recorded by nearby microphones. We present the results of the project in terms of the potential for sonic-boom-induced false alarms in Earthquake Warning Systems, and highlight some of the interesting features of the dataset.

Characterization of the porosity in Boom (Mol site, Belgium) and Opalinus (Mont Terri, Switzerland) clays - about the benefit of using ion beam milling tools and CRYO-SEM

International Nuclear Information System (INIS)

Desbois, G.; Houben, M.E.; Sholokhova, Y.; Urai, J.L.; Kukla, P.A.

2010-01-01

imaging of pore space at high resolution. The first of them is to use ion beam milling tools able to prepare smooth, damage free cross-sectioned surfaces. Two main ion source are available: (1) a broad ion beam (BIB, up to 3.5 mA) is suitable to produce large polished cross-sections area of few mm 2 , while the focused ion beam (FIB, 1 pA - 45 nA) is better used for fine and precise polished cross-sections area of about few μm 2 . The second alternative is to preserve the in-situ nanostructures of wet clay-stones by using cryogenic techniques in order to stabilize in-situ fluids at temperature of liquid nitrogen. A FIB/BIB-cryo- SEM instrument combines cryo-techniques to preserve wet samples, in-situ sample preparation by ion beam cross-sectioning (BIB or FIB) and observations of the stabilized microstructure at high resolution (SEM). Since the ion beam is directly embedded into the SEM, this instrument offers a unique way to get a direct access of the pore space in 3D by using a 'slice and view' procedure equivalent to nano-serial sectioning. This procedure allows us investigating the natural in-situ pore space as a 3D matrix. This contribution reports on a study of Boom and Opalinus clays from reference sites for research (respectively at Mol site, Belgium and Mont Terri, Switzerland) using cryo-SEM at cryogenic temperature, with ion beam cross-sectioning to prepare smooth, damage free surfaces. Pores commonly have crack-like tips, preferred orientation parallel to bedding and power law size distribution. We define a number of pore types depending on shape and location in the microstructure. 3-D reconstruction by serial cross-sectioning shows 3-D connectivity of the pore space and provide natural pore matrix for simulation of permeability using Lattice Boltzmann method. These findings offer a new insight into the morphology of pores and quantification of porosity down to nano-scale and provide the basis for microstructure-based models of transport in clays

Dynamic Analysis of The Intelligent Sprayer Boom

DEFF Research Database (Denmark)

Wiggers, Sine Leergaard; Maagaard, Jørgen; Terp, Christian Istjord

called “The intelligent sprayer boom”. For the sprayer boom the primary challenge is to hit the weeds with precision from a movable platform. Since the sprayer boom is mounted on a tractor the system will react to bumps in the field. The intelligent sprayer boom has an integrated camera technology......As part of the 3 year project “The intelligent Sprayer Boom”, financed by The Danish National Advanced Technology Foundation, the dynamics of the sprayer boom is to be analysed. In order to minimize the amount of herbicides used to kill the weeds in agriculture a new sprayer boom is being developed...

Current status and future plan of the research on the rock deformation and disturbed zone within the Hades project

International Nuclear Information System (INIS)

Neerdael, Bernard; Bruyn, D.de; Volckaert, Geert

1994-01-01

In the framework of the high activity disposal experimental site (HADES) project managed by the Belgian Nuclear Research Establishment, an in situ research program was launched in 1980. An underground research facility was built in a deep Tertiary clay formation. The various issues related to the site characterization were investigated, including the performance of engineered barriers. Most of the research has been performed under the contract with the Commission of European Communities (CEC) and the Belgian Waste Management Authority (ONDRF/NIRAS). Various civil engineering works and underground experiments haave been carried out to assess the technical feasibility of building a high level waste repository in a plastic clay formaiton. Further information has been collected on the extent and the evolution of the disturbance caused in clay mass by underground structures. The study on clay behavior was extended to the near field conditions after disposal when the host rocks underwent the thermal effect of heat-emitting waste. The general background of the Boom clay, the mechanical behavior of the Boom clay, the numerical simulation of excavation progress and backfill materials are reported. (K.I.)

Recent Progress on Sonic Boom Research at NASA

Science.gov (United States)

Loubeau, Alexandra

2012-01-01

Sonic boom research conducted at NASA through the Supersonics Project of the Fundamental Aeronautics Program is oriented toward understanding the potential impact of sonic boom noise on communities from new low-boom supersonic aircraft designs. Encompassing research in atmospheric propagation, structural response, and human response, NASA research contributes to knowledge in key areas needed to support development of a new noise-based standard for supersonic aircraft certification. Partnerships with several industry, government, and academic institutions have enabled the recent execution of several acoustic field studies on sonic booms. An overview of recent activities funded by NASA includes: focus boom model development and experimental validation, field experiments of structural transmission of sonic booms into large buildings, and low boom community response testing.

Basin sidewall effects during comparable boom testing

International Nuclear Information System (INIS)

DeVitis, D.S.; Hannon, L.

1995-01-01

A quantitative investigation of the effects of boom sidewall clearance during first and gross oil loss speed tests was discussed. A second measure of sidewall was quantified in terms of flow characteristics at specific location in the boom apex. The test boom was rigged in 5 different configurations. First oil loss and gross oil loss tow speeds, and relative horizontal flow velocities within the boom apex were obtained for each configuration. Flow velocities of 0.5 to 1.5 knots in 0.25 knot increments were measured. Flow velocities illustrated similar flow characteristics within the apex regardless of side wall clearance. The results of the study illustrated that boom to basin sidewall clearance may be an independent test parameter without a significant bias. 5 tabs., 8 figs.,

Investigations for the influence of geochemical parameters on the sorption and desorption of lanthanides and uranium onto opalinus clay as potential host rock for a repository

International Nuclear Information System (INIS)

Moeser, Christina

2010-01-01

The development of a disposal in deep geological formations for radioactive waste is a very important task for the future. The safety assessment for more than a hundred thousand years needs a full understanding of all processes of interaction between the radioactive waste and the surrounded formations. This work contributes to this understanding. The interaction between lanthanides (homologues of the actinides americium, curium and berkelium) / uranium and the host rock opalinus clay under influence of organic substances (NOM) have been analyzed and discussed. The complex system was split into 3 binary basic systems with the following interactions - Interactions between lanthanides / uranium and NOM - Interactions between lanthanides / uranium and the opalinus clay - Interactions between NOM and opalinus clay All binary systems can be influenced by geological parameters like pH, ion strength and competing cations. The sorption / desorption of the lanthanides onto the opalinus clay is analyzed via inductively coupled plasma mass spectrometry. For the investigation of the complexation behavior of metals with NOM we used capillary electrophoresis coupled with inductively coupled plasma mass spectrometry. Under these conditions the chosen model organic humic acid affected the sorption of the lanthanides onto opalinus clay favorably. The smaller organic compounds, which dominate in the composition of the clay organics, remobilized the metals after sorption onto clay and the sorption can be inhibited by NOM. Due to the reduced metal sorption onto Opalinus clay by NOM, a migration through the clay may be possible.

Swarm Deployable Boom Assembly (DBA) Development of a Deployable Magnetometer Boom for the Swarm Spacecraft

Science.gov (United States)

McMahon, Paul; Jung, Hans-Juergen; Edwards, Jeff

2013-09-01

The Swarm programme consists of 3 magnetically clean satellites flying in close formation designed to measure the Earth's magnetic field using 2 Magnetometers mounted on a 4.3m long deployable boom.Deployment is initiated by releasing 3 HDRMs, once released the boom oscillates back and forth on a pair of pivots, similar to a restaurant kitchen door hinge, for around 120 seconds before coming to rest on 3 kinematic mounts which are used to provide an accurate reference location in the deployed position. Motion of the boom is damped through a combination of friction, spring hysteresis and flexing of the 120+ cables crossing the hinge. Considerable development work and accurate numerical modelling of the hinge motion was required to predict performance across a wide temperature range and ensure that during the 1st overshoot the boom did not damage itself, the harness or the spacecraft.Due to the magnetic cleanliness requirements of the spacecraft no magnetic materials could be used in the design of the hardware.

A natural ice boom

Energy Technology Data Exchange (ETDEWEB)

Hopper, H.R. [Manitoba Hydro, Winnipeg, MB (Canada)

1998-10-01

Planning for ice jams and ice movements are critical on the Nelson River in northern Manitoba in designing cofferdams. Experience on the St. Lawrence River demonstrated the possibility of exercising some control over ice action by judicious placement of log booms or ice control structures. The success of experiments with man-made controls led to field tests in which an ice sheet of sufficient magnitude and competence was introduced into the open water stream of the Nelson River. The ice sheet was subsequently jammed in a narrow channel, thereby creating a natural ice bridge or boom upstream of a proposed hydro development. Under favourable conditions, this boom would initiate the progression of the ice cover from its location upstream, cutting off the downstream reach from the ice producing potential of the upstream reach. Although ice would still be generated downstream, the length of the reach between the ice boom and the development site would be short enough that ice jamming at the development site would never occur. Although problems in blasting prevented the introduction of a competent ice sheet into the main stream of the river at the location chosen, sufficient confidence in the theory was gained to warrant further consideration. 4 refs., 1 tab., 10 figs.

Domestic Crop Booms, Livelihood Pathways and Nested Transitions: Charting the Implications of Bangladesh’s Pangasius Boom

NARCIS (Netherlands)

Belton, B.; Asseldonk, van I.J.M.; Bush, S.R.

2017-01-01

Rapidly transforming Asian food systems are oriented largely towards domestic markets, yet literature on Asian crop booms deals almost exclusively with commodities produced for export. With reference to pangasius aquaculture in Bangladesh, we argue that ‘domestic crop booms’ - agricultural booms

Testing fire resistant boom in waves and flames

International Nuclear Information System (INIS)

McCourt, J.; Buist, I.; Pratte, B.; Jamieson, W.; Mullin, J.

1997-01-01

A near full-scale screening test to evaluate the durability and ability of refractory-fabric fire resistant booms to contain oil during an in-situ burn without the environmental problems of burning crude oil or the cost of testing offshore, was developed. The boom was first flexed under tension for two hours, then deployed in a U-configuration in an outdoor wave tank. Propane gas was burned in the pocket of the boom to simulate the collection and burning phases of an in-situ burn. Finally, the boom was returned to the indoor wave flume for another two hours of wave action and then inspected for damage. Results indicated damage of the same type as suffered in previously conducted sea trials, although the extent of damage was less severe. These results led to recommendations for improvement of the test protocol which included: (1) increasing the heat flux to the boom, (2) improving the heat flux measurement, (3) increasing the tension in the fire boom during flame testing, and (4) improving the characterization of the waves near the fire boom. 16 refs., 6 figs

The general situation of clay site for high-level waste geological disposal repository

International Nuclear Information System (INIS)

Wang Changxuan; Liu Xiaodong; Liu Pinghui

2008-01-01

Host medium is vitally important for safety of high-level radiaoactive waste (HLW) geological disposal. Clay, as host media of geological repository of HLW, has received greater attention for its inherent advantages. This paper summarizes IAEA and OECD/NEA's some safety guides on site selection and briefly introduces the process of the site selection, their studies and the characteristics of the clay formations in Switz-erland, France and Belgian. Based on these analyses, some suggestions are made to China's HLW repository clay site selection. (authors)

Waveforms and Sonic Boom Perception and Response (WSPR): Low-Boom Community Response Program Pilot Test Design, Execution, and Analysis

Science.gov (United States)

Page, Juliet A.; Hodgdon, Kathleen K.; Krecker, Peg; Cowart, Robbie; Hobbs, Chris; Wilmer, Clif; Koening, Carrie; Holmes, Theresa; Gaugler, Trent; Shumway, Durland L.;

Radiocarbon dating of groundwater in the vicinity of a potential repository in clay for radioactive waste disposal

International Nuclear Information System (INIS)

Marmol, P. del

1984-12-01

In the context of a study of Boom clay in Mol (Belgium) for the purpose of storing radioactive waste, 14 C activity measurements of the surrounding aquifers have been carried on in the Kempen region to investigate their flow patterns. This work is done in conjunction with classical hydrogeological methods, and a mathematical modelling of the aquifer system. Radiochemical dating is believed to give a decisive support to the hydrogeological modelling approaches. 43 wells in 11 locations have been sampled for 14 C isotopic and chemical analyses. So far 34 14 C and 23 13 C/ 12 C isotopic ratios are available. Preliminary results are presented. The decreasing trend in 14 C activity with depth from Neogene to older layers is generally observed. The 14 C activities of the Berg sands in general are discussed. The 14 C data compared to the piezometric measurements cannot be explained without taking into account a contribution through seepage from one or more other aquifers. A positive 14 C measurement in the interstitial water of the Boom clay confirms this view. This work will be pursued as many more data are needed to reach any quantitative conclusion

Clay club catalogue of characteristics of argillaceous rocks

International Nuclear Information System (INIS)

2005-01-01

The OECD/NEA Working Group on the Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations, namely the Clay Club, examines the various argillaceous rocks that are being considered for the deep geological disposal of radioactive waste, i.e. from plastic, soft, poorly indurated clays to brittle, hard mud-stones or shales. The Clay Club considered it necessary and timely to provide a catalogue to gather in a structured way the key geo-scientific characteristics of the various argillaceous formations that are - or were - studied in NEA member countries with regard to radioactive waste disposal. The present catalogue represents the outcomes of this Clay Club initiative. (author)

Del Boom y otras onomatopeyas literarias

Directory of Open Access Journals (Sweden)

Jorge Iván Parra Londoño

2016-03-01

Full Text Available Este artículo trata de examinar los alcances literarios del llamado Boom latinoamericano, a medio siglo de su estallido, las cuatro obras más representativas y sus respectivos autores, además de proponer un quinto autor, según la invitación que hiciera en su momento el crítico Ángel Rama. Por otro lado, evalua la respuesta literaria por parte del Post Boom, analizando sus características y su vigencia y, de manera concomitante, los movimientos anejos o posteriores a dicho movimiento, como el Crack y la Generación Granta. A manera de propuesta, se pondrán a consideración treinta autores como integrantes del Post Boom y una novela de Carlos Fuentes como el “crash” del Boom. Por último, presenta un breve vistazo a la narrativa española paralela a los mencionados movimientos.

Interaction between clay-based sealing components and crystalline host rock

Science.gov (United States)

Priyanto, D. G.; Dixon, D. A.; Man, A. G.

The results of hydraulic-mechanical (H-M) numerical simulation of a shaft seal installed at a fracture zone (FZ) in a crystalline host rock using the finite element method are presented. The primary function of a shaft seal is to limit short-circuiting of the groundwater flow regime via the shaft in a deep geological repository. Two different stages of system evolution were considered in this numerical modelling. Stage 1 simulates the groundwater flow into an open shaft, prior to seal installation. Stage 2 simulates the groundwater flow into the shaft seal after seal installation. Four different cases were completed to: (i) evaluate H-M response due to the interaction between clay-based sealing material and crystalline host rock in the shaft seal structure; (ii) quantify the effect of the different times between the completion of the shaft excavation and the completion of shaft seal installation on the H-M response; and (iii) define the potential effects of different sealing material configurations. Shaft sealing materials include the bentonite-sand mixture (BSM), dense backfill (DBF), and concrete plug (CP). The BSM has greater swelling capacity and lower hydraulic conductivity ( K) than the DBF. The results of these analyses show that the decrease of the pore water pressure is concentrated along the fracture zone (FZ), which has the greatest K. As the time increases, the greatest decrease in pore water pressure is found around the FZ. Following FZ isolation and the subsequent filling of the shaft with water as it floods, the pore water pressure profile tends to recover back to the initial conditions prior to shaft excavation. The majority of the fluids that ultimately saturate the centre of the shaft seal flow radially inwards from the FZ. The time between the completion of the shaft excavation and the completion of shaft seal installation has a significant effect on the saturation time. A shorter time can reduce the saturation time. Since most of the inflow

Warmed up for ten-year test in the Boom Clay formation PRACLAY Heater Experiment is launched

International Nuclear Information System (INIS)

2015-01-01

The article discusses latest developments concerning the PRACLAY Heater Experiment. The PRACLAY experiment investigates the impact of heat on the properties of clay adjacent to a repository for the geological disposal of radioactive waste. Results from the PRACLAY experiment will provide significant input for the NIRAS research programme on the disposal of high-level and long-lived radioactive waste in clay formations.The heating phase of the PRACLAY underground experiment was launched in 2014. The latest preparations comprised the improvement and installation of a back-up heating system. In the future, the control, monitoring, and analysis and interpretation of the measured data will receive the greatest attention in the PRACLAY Heater Experiment.

The Effect of Sonic Booms on Earthquake Warning Systems

Science.gov (United States)

Wurman, Gilead; Haering, Edward A, Jr.; Price, Michael J.

2011-01-01

Several aerospace companies are designing quiet supersonic business jets for service over the United States. These aircraft have the potential to increase the occurrence of mild sonic booms across the country. This leads to interest among earthquake warning (EQW) developers and the general seismological community in characterizing the effect of sonic booms on seismic sensors in the field, their potential impact on EQW systems, and means of discriminating their signatures from those of earthquakes. The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. (SWS) and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on EQW sensors. The study consists of exposing high-sample-rate (1000 sps) triaxial accelerometers to sonic booms with overpressures ranging from 10 to 600 Pa in the free field and the built environment. The accelerometers record the coupling of the sonic boom to the ground and surrounding structures, while microphones record the acoustic wave above ground near the sensor. Sonic booms are broadband signals with more high-frequency content than earthquakes. Even a 1000 sps accelerometer will produce a significantly aliased record. Thus the observed peak ground velocity is strongly dependent on the sampling rate, and increases as the sampling rate is reduced. At 1000 sps we observe ground velocities that exceed those of P-waves from ML 3 earthquakes at local distances, suggesting that sonic booms are not negligible for EQW applications. We present the results of several experiments conducted under SonicBREWS showing the effects of typical-case low amplitude sonic booms and worst-case high amplitude booms. We show the effects of various sensor placements and sensor array geometries. Finally, we suggest possible avenues for discriminating sonic booms from earthquakes for the purposes of EQW.

Liquid clay emulsion--alternate daily cover and erosion

Energy Technology Data Exchange (ETDEWEB)

Martell, L. [L/M Chemical Service, Ancona, IL (United States)

1995-12-31

Formula 480 Biodegradable Clay Based Product, developed in 1985, is a non-toxic liquid bentonite clay product that comes in concentrate form for dilution with water and/or leachate. The concentrate allows this product y to be used for erosion and dust control, grass seeding, as well as a daily or intermediate cover for landfills. It inhibits the activities of birds and vectors, while controlling dust, erosion, odor, and blowing debris. By varying the dilution of Formula 480, the product can be set up from porous and flexible, to durable and waterproof. Having a clay base, high cation exchange capacity offers nutrient stabilization for grass seeding. When using leachate for product dilution, it will percolate, waterproof, and be recycled back into the surface as a solid. The product is economical at $.03 to $.08/sq.ft., depending on thickness of application, smoothness of surface or compaction ratio. Application is done with a self-contained sprayer developed specifically for Formula 480. It can be sprayed with a high volume handgun or an economical and efficient spray boom. This product is cleared for use in over 15 states and is currently being used on hazardous and non-hazardous fills throughout the U.S. and Germany. Ease of application, economy, and effectiveness warrants people to look at this product for many uses.

Study of the behaviour of clay by frequency analysis of the seismic wave

International Nuclear Information System (INIS)

Sloovere, P. de.

1990-01-01

Any alteration in the mechanical characteristics of a medium modifies the frequency spectrum of a signal passing through the medium. In order to make use of this property, it was first necessary to construct a trial shear wave hammer generator. The waves transmitted in this way are received by a sound detector system, then they are treated by an appropriate computer program. The device has been applied successfully in the Boom clay in the vicinity of the CEN/SCK underground laboratory in Mol (Belgium)

Radionuclide release from high level waste forms under repository conditions in clay or granite

International Nuclear Information System (INIS)

Godon, N.; Lanza, F.

1990-01-01

The behaviour of both fully active and simulated vitrified high level waste (HLW) has been studied under conditions that are likely to occur in future repositories in clay and granite. The simulated HLW was doped with Cs, Sr, Tc and the actinides and the leaching of these elements from the glass has been measured together with their concentrations in the water of the near-field and their distribution between the various components of the repository. The diffusion coefficients of several elements in Boom clay has also been measured. The results show that the concentrations of Tc and the actinides in the near-field of a repository will be very low and that the actinides will only diffuse very slowly away from the vicinity of the glass. 24 refs., 1 figs., 7 tabs

Subjective Response to Simulated Sonic Booms in Homes

Science.gov (United States)

McCurdy, David A.; Brown, Sherilyn A.

1996-01-01

One of the environmental issues affecting the development of a second-generation supersonic commercial transport is the impact of sonic booms on people. Aircraft designers are attempting to design the transport to produce sonic boom signatures that will have minimum impact on the public. Current supersonic commercial aircraft produce an 'N-wave' sonic boom pressure signature that is considered unacceptable by the public. This has resulted in first-generation supersonic transports being banned from flying supersonic over land in the United States, a severe economic constraint. By tailoring aircraft volume and lift distributions, designers hope to produce sonic boom signatures having specific shapes other than 'N-wave' that may be more acceptable to the public. As part of the effort to develop a second-generation supersonic commercial transport, Langley Research Center is conducting research to study people's subjective response to sonic booms. As part of that research, a system was developed for performing studies of the subjective response of people to the occurrence of simulated sonic booms in their homes. The In-Home Noise Generation/Response System (IHONORS) provides a degree of situational realism not available in the laboratory and a degree of control over the noise exposure not found in community surveys. The computer-controlled audio system generates the simulated sonic booms, measures the noise levels, and records the subjects' ratings and can be placed and operated in individual homes for extended periods of time. The system was used to conduct an in-home study of subjective response to simulated sonic booms. The primary objective of the study was to determine the effect on annoyance of the number of sonic boom occurrences in a realistic environment. The effects on annoyance of several other parameters were also examined. Initially, data analyses were based on all the data collected. However, further analyser found that test subjects adapted to the sonic

The TIMODAZ project: Thermal impact on the damaged zone around a radioactive waste disposal in clay host rocks

International Nuclear Information System (INIS)

XiangLing, L.

2009-01-01

The management of spent nuclear fuel and other long-lived radio active waste is an important environmental issue today. Disposal in deep clay geological formations is one of the promising options to dispose of these wastes. In this context, the related research activities in the Euratom Framework Programme of European Commission are continually taking on an enhanced significance. The TIMODAZ is one of the STREP projects (Specific Targeted Research Project) in the Sixth EURATOM Framework Programme and contributes to the research related to the geological disposal of radioactive waste. The consortium is composed of a strong multidisciplinary team involving both European radioactive waste management organizations and nuclear research institutes, universities, industrial partners as well as consultancy companies (SME's). Totally, 15 partners coming from 8 countries are involved with a total budget of about 4000k EURO. Being the coordinator (through the EURIDICE expertise group), SCK-CEN plays the leading role in the project. Meanwhile, SCK-CEN participates the research in different work packages covering the laboratory tests, in-situ tests as well as the integration of TIMODAZ results within the safety case. An important item for the long-term safety of underground disposal is the proper evaluation of the DZ (damaged zone) in the clay host rock. The DZ is defined here as the zone of host rock that experiences THMC (Thermo-Hydro-Mechanical-Chemical) modifications induced by the repository, with potential major changes in the transport properties for radionuclides. The DZ is first initiated during the repository construction. Its behaviour is dynamic, dependent on changing conditions that vary from the open-drift period, to initial closure period and to the entire heating-cooling cycle of the decaying waste. The early THMC disturbances created by the excavation, the operational phase and the thermal load might be the most severe transient that the repository will undergo

Heat production / host rock compatibility; Waermeentwicklung / Gesteinsvertraeglichkeit

Energy Technology Data Exchange (ETDEWEB)

Meleshyn, A.; Weyand, T.; Bracke, G.; Kull, H.; Wieczorek, K.

2016-05-15

For the final high-level radioactive waste repository potential host rock formations are either rock salt or clays (Kristallin). Heat generating waste (decay heat of the radioactive materials) can be absorbed by the host rock. The effect of temperature increase on the thermal conductivity, the thermal expansion and the mechanical properties of salt, Kristallin, clays and argilliferous geotechnical barriers are described. Further issues of the report are the mineralogical behavior, phase transformations, hydrochemistry, microbial processes, gas formation, thermochemical processes and gas ingress. Recommendations for further research are summarized.

Full-Carpet Design of a Low-Boom Demonstrator Concept

Science.gov (United States)

Ordaz, Irian; Wintzer, Mathias; Rallabhandi, Sriram K.

2015-01-01

The Cart3D adjoint-based design framework is used to mitigate the undesirable o -track sonic boom properties of a demonstrator concept designed for low-boom directly under the flight path. First, the requirements of a Cart3D design mesh are determined using a high-fidelity mesh adapted to minimize the discretization error of the CFD analysis. Low-boom equivalent area targets are then generated at the under-track and one off-track azimuthal position for the baseline configuration. The under-track target is generated using a trim- feasible low-boom target generation process, ensuring that the final design is not only low-boom, but also trimmed at the specified flight condition. The o -track equivalent area target is generated by minimizing the A-weighted loudness using an efficient adjoint-based approach. The configuration outer mold line is then parameterized and optimized to match the off-body pressure distributions prescribed by the low-boom targets. The numerical optimizer uses design gradients which are calculated using the Cart3D adjoint- based design capability. Optimization constraints are placed on the geometry to satisfy structural feasibility. The low-boom properties of the final design are verified using the adaptive meshing approach. This analysis quantifies the error associated with the CFD mesh that is used for design. Finally, an alternate mesh construction and target positioning approach offering greater computational efficiency is demonstrated and verified.

Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal

International Nuclear Information System (INIS)

Marschall, P.; Horseman, S.; Gimmi, T.

2005-01-01

The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10 -20 to 10 -21 m 2 and a moderate anisotropy ratio ≤ 10. Porosity depends on clay content and burial depth; values of ∼ 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

Spray boom for selectively spraying a herbicidal composition onto dicots

DEFF Research Database (Denmark)

2012-01-01

There is provided a method and spray boom for discriminating cereal crop (monocot) and weeds (dicots). The spray boom includes means for digitally recording an image of a selected area to be treated by a nozzle on the spray boom, whereby a plant material is identified based on a segmentation proc...

Hydro-mechanical behaviour of two reference Belgian clay formations under non-isothermal conditions

International Nuclear Information System (INIS)

Lima, A.; Romero, E.; Gens, A.; Li, X.L.

2012-01-01

Document available in extended abstract form only. Two deep clay formations are being investigated in Belgium in connection with the design of a repository for 'High-Level Radioactive Waste': Boom clay BC at Mol (located between 160 and 270 m depths), considered the reference host formation, and Ypresian clay YC at Kallo (located between 300 and 450 m depths) as an alternative one. A comprehensive experimental programme has been carried out on these materials to explore water permeability at different temperatures and sample orientations, as well as to analyse volume change behaviour on loading/unloading at different temperatures and sample orientations (including pre and post-yield compressibility, yield properties and volume changes on drained thermal loading). Table 1 summarises some properties of BC and YC. Figure 1 presents the pore size distribution PSD curves of both clays obtained by mercury intrusion porosimetry. They display contrasting features (bi-modal pore network in YP with larger dominant pore sizes). Larger water permeability values are expected on YC as indicated in Table 1 and Figure 2, not only as a consequence of its higher void ratio but also due to these double porosity features. Water retention properties, of particular concern on sample retrieval from large depths, are also affected due to desaturation processes that are associated with the double porosity network of YP and its effects on air-entry value (a lower initial suction is measured on YP, despite being retrieved from larger depths). Figure 2 shows vertical and horizontal water permeability results under constant volume conditions and different temperatures. BC and YC display small anisotropy at sample scale - permeability is slightly larger on horizontal direction-. With regard to temperature effects, the figure shows that water permeability dependency on temperature in YC is slightly higher than the water viscosity prediction for both orientations. Instead BC displayed a thermal

Far Field Sorption Data Bases for Performance Assessment of a High-Level Radioactive Waste Repository in an Undisturbed Opalinus Clay Host Rock

International Nuclear Information System (INIS)

Bradburry, M.; Baeyens, B.

2003-08-01

An Opalinus Clay formation in the Zuercher Weinland is under consideration by Nagra as a potential location for a high-level and long-Iived intermediate-level radioactive waste repository. Performance assessment studies will be performed for this site and the purpose of this report is to describe the procedures used to develop sorption data bases appropriate for an undisturbed Opalinus Clay host rock which are required for such safety analysis calculations. In tight, low water content argillaceous rock formations such as Opalinus Clay, there is uncertainty concerning the in situ pH/P CO 2 . In order to take this intrinsic uncertainty into account porewater chemistries were calculated for a reference case, pH = 7.24, and for two other pH values, 6.3 and 7.8. Sorption data bases are given for the three cases. The basis for the sorption data bases is 'in-house' sorption measurements for Cs(I), Sr(II), Ni(II), Eu(III), Sn(IV), Se(IV), Th(IV) and I(-I) carried out on Opalinus Clay samples from Mont Terri (Canton Jura) since at the time the experiments were performed no core samples from the Benken borehole (Zuercher Weinland) were available. The Opalinus Clay at Mont Terri and Benken are part of the same geological formation . Despite having directly measured data for the above key radionuclides, some of the required distribution ratios (Rd) used to generate the sorption data bases still came from the open literature. An important part of this report is concerned with describing the procedures whereby these selected literature Rd values were modified so as to apply to the Benken Opalinus Clay mineralogy and groundwater chemistries calculated at the three pH values given above. The resulting Rd values were then further modified using so-called Lab→Field transfer factors to produce sorption values which were appropriate to the in situ bulk rock for the selected range of water chemistry conditions. Finally, it is important to have some appreciation of the uncertainties

Development in helicopter tail boom strake applications in the US

Science.gov (United States)

Wilson, John C.; Kelley, Henry L.; Donahue, Cynthia C.; Yenni, Kenneth R.

1988-01-01

The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power.

NOFI oil Vee-Sweep and extension boom test at OHMSETT

International Nuclear Information System (INIS)

Bitting, K.R.; Vicedomine, J.

1993-01-01

The NOFI Vee-Sweep is an inflatable oil collection boom held in a V configuration by cross netting attached to the skirt of the boom. The NOFI 600S is an inflatable oil boom used to divert oil into the Vee-Sweep. The lower section of the 600S skirt consists of a feather net and a ballast chain. The booms are designed for open-ocean skimming where a skimmer is placed in the Vee-Sweep apex to remove the collected oil. During testing, the booms were preloaded with oil and towed in the OHMSETT tank at various speeds and wave conditions. Each boom was tested for its first and gross (continuous) oil loss speeds. The Vee-Sweep was also evaluated for wave performance, oil thickness vs tow speed, oil loss rate, and critical tow speed. Finally, a DESMI-250 oil skimmer was placed in the Vee-Sweep apex and oil loss tests were run while the skimmer was operating. During the critical tow speed testing, failures occurred due to apex submergence at ca 3.5 knots in calm water and short-crested waves, and 2.4 knots in harbor chop. The oil loss tests showed that the Vee-Sweep retains oil at speeds significantly higher than conventional booms. First oil loss speeds ranged from 1.3 knots in calm water to 1.0 knot in regular waves. The Vee-Sweep's high buoyancy/weight ratio gave it good wave performance in all conditions tested. The 600S oil loss speeds were higher than those of most conventional booms, and performance was better when the feather net was attached. 1 ref., 4 figs., 4 tabs

Environmental Pollution: Noise Pollution - Sonic Boom

Science.gov (United States)

1977-06-01

UNCLASSIFIED AD-A041 400 DDC/BIB-77/06 ENVIRONMENTAL POLLUTION NOISE POLLUTION SONIC BOOM A DDC BIBLIOGRAPHY DDC-TAS Cameron Station Alexandria, Va...rn7Sttio 658S-A041 400 4 TITLE xand r.VuhtlVlia) 2 TA i b- 1iblog ra ph y ENVIRONMENTAL POLLUTION : --. Apr-l IM59-Jul, 7NOISE POLLUTION -SONIC BOOM. 1,976...BIBLIOGRAPHY SEARCH CONTROL NO. /2OM09 AD- 769 970 20/1 1/3 DEFENSE UOCUMENTATION CENTER ALEXANDRIA VA ENVIRONMENTAL POLLUTION : NOISE POLLUTION

Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to

Science.gov (United States)

Coast Hybrid and Electric Vehicles Boom Coast to Coast to someone by E-mail Share Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to Coast on Facebook Tweet about Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to Coast on Twitter Bookmark Alternative

Evaluating a protocol for testing fire-resistant oil-spill containment boom

International Nuclear Information System (INIS)

Walton, W.D.; Twilley, W.H.; Hiltabrand, R.R.; Mullin, J.V.

1998-01-01

A series of experiments were conducted to evaluate a protocol for testing the ability of fire-resistant booms to withstand both fire and waves. Most response plans for in situ burning of oil at sea require the use of a fire-resistant boom to contain the oil during a burn. For this study, a wave tank was designed and constructed to assess the capabilities of a 15 m section of a boom subjected to a 5 m diameter fire with 0.15 m high waves. Five typical fire-resistant oil-spill containment booms were tested. The purpose of the project was to evaluate the test procedure, therefore the overall performance of the boom was not evaluated on a pass-fail criterion. The two most important aspects of the test method were repeatability and reproducibility. Some of the parameters tested included the effect of wind, waves, fire size, and fire duration. Methods to constrain the booms were also tested. 7 refs., 6 tabs., 7 figs

State of the art of sonic boom modeling

Science.gov (United States)

Plotkin, Kenneth J.

2002-01-01

Based on fundamental theory developed through the 1950s and 1960s, sonic boom modeling has evolved into practical tools. Over the past decade, there have been requirements for design tools for an advanced supersonic transport, and for tools for environmental assessment of various military and aerospace activities. This has resulted in a number of advances in the understanding of the physics of sonic booms, including shock wave rise times, propagation through turbulence, and blending sonic boom theory with modern computational fluid dynamics (CFD) aerodynamic design methods. This article reviews the early fundamental theory, recent advances in theory, and the application of these advances to practical models.

A Study of Clay-Epoxy Nanocomposites Consisting of Unmodified Clay and Organo Clay

Directory of Open Access Journals (Sweden)

Graham Edward

2006-04-01

Full Text Available Clay-epoxy nanocomposites were synthesized from DGEBA resin and montmorillonite clay with an in-situ polymerization. One type of untreated clay and two types of organo clay were used to produce the nanocompsoites. The aims of this study were to examine the nanocomposite structure using different tools and to compare the results between the unmodified clay and modified clays as nanofillers. Although diffractogram in reflection mode did not show any apparent peak of both types of materials, the transmitted XRD (X-Ray Difraction graphs, DSC (Differential Scanning Calorimeter analysis and TEM (Transmission Electron Microscope images revealed that the modified clay-epoxy and unmodified clay-epoxy provides different results. Interestingly, the micrographs showed that some of the modified clay layers possessed non-exfoliated layers in the modified clay-epoxy nanocomposites. Clay aggregates and a hackle pattern were found from E-SEM images for both types of nanocomposite materials. It is shown that different tools should be used to determine the nanocomposite structure.

Methodology for the Regulation of Boom Sprayers Operating in Circular Trajectories

Directory of Open Access Journals (Sweden)

Alfredo Serreta

2011-04-01

Full Text Available A methodology for the regulation of boom sprayers working in circular trajectories has been developed. In this type of trajectory, the areas of the plots of land treated by the outer nozzles of the boom are treated at reduced rates, and those treated by the inner nozzles are treated in excess. The goal of this study was to establish the methodology to determine the flow of the individual nozzles on the boom to guarantee that the dose of the product applied per surface unit is similar across the plot. This flow is a function of the position of the equipment (circular trajectory radius and of the displacement velocity such that the treatment applied per surface unit is uniform. GPS technology was proposed as a basis to establish the position and displacement velocity of the tractor. The viability of this methodology was simulated considering two circular plots with radii of 160 m and 310 m, using three sets of equipment with boom widths of 14.5, 24.5 and 29.5 m. Data showed as increasing boom widths produce bigger errors in the surface dose applied (L/m2. Error also increases with decreasing plot surface. As an example, considering the three boom widths of 14.5, 24.5 and 29.5 m working on a circular plot with a radius of 160 m, the percentage of surface with errors in the applied surface dose greater than 5% was 30%, 58% and 65% respectively. Considering a circular plot with radius of 310 m the same errors were 8%, 22% and 31%. To obtain a uniform superficial dose two sprayer regulation alternatives have been simulated considering a 14.5 m boom: the regulation of the pressure of each nozzle and the regulation of the pressure of each boom section. The viability of implementing the proposed methodology on commercial boom sprayers using GPS antennas to establish the position and displacement velocity of the tractor was justified with a field trial in which a self-guiding commercial GPS system was used along with three precision GPS systems located in

Stress Analysis of Boom of Special Mobile Crane for Plain Region in Transmission Line

Science.gov (United States)

Qin, Jian; Shao, Tao; Chen, Jun; Wan, Jiancheng; Li, Zhonghuan; Jiang, Ming

2017-10-01

Basis of the boom force analysis of special mobile crane for plain region in transmission line, the load type of boom design is confirmed. According to the different combinations of boom sections, the composite pattern of the different boom length is obtained to suit the actual conditions of boom overlapping. The large deformation model is employed with FEM to simulate the stress distribution of boom, and the calculation results are checked. The performance curves of rated load with different arm length and different working range are obtained, which ensures the lifting capacity of special mobile crane meeting the requirement of tower erection of transmission line. The proposed FEM of boom of mobile crane would provide certain guiding and reference to the boom design.

Design of the De-Orbit Sail Boom Deployment Unit

Science.gov (United States)

Meyer, Sebastian; Hillebrandt, Martin; Straubel, Marco; Huhne, Christian

2014-06-01

The design of the De-Orbit Sail boom deployment unit is strongly driven by volume constraints, which are given by the cubesat container. Four CFRP (carbon fiber reinforced polymer) booms [4] with a cross-sectional shape of a double-omega and a length of 3.6 m are reeled on one spool in the center of the unit. The deployment of the four booms are controlled by an electric motor, which acts on the boom spool. Due to the volume limitation caused by the dimensions of the cubesat deployer the deployment unit has little room for the mechanisms components. With the aim to achieve a robust design, the deployment concept of the unit has greatly changed during the development process. The history of the design as well as the mechanisms are described. Additionally the results of the flight model testing are presented.

Influence of carbonate micro-fabrics on the failure strength of Callovo-Oxfordian clay stones and Opalinus Clay

International Nuclear Information System (INIS)

Klinkenberg, M.; Dohrmann, R.; Kaufhold, S.; Siegesmund, S.

2010-01-01

Document available in extended abstract form only. The potential use of clay stones as host rock for radioactive waste disposal is currently investigated. For this application, hydraulic conductivity, swelling properties, water uptake, rheological and mechanical properties are of great importance. The Opalinus Clay (Mont-Terri, Switzerland) and the Callovo- Oxfordian clay stone (France) are the most frequently studied clay stones. One goal is to develop a numerical model being able to predict the mechanical behaviour of clay stones under repository-like conditions. Experimental investigations reveal that Opalinus Clay and Callovo-Oxfordian clay stone behave different with respect to the dependence of mechanical strength on the carbonate content. The failure strength of Opalinus Clay decreases with increasing carbonate content, whereas it increases with increasing carbonate content when Callovo-Oxfordian clay stone is considered. To supply proper data and enable reliable model assumptions, the use of suitable experimental techniques for the description of the microstructure is indispensable. After mechanical testing, samples were taken perpendicular to the bedding and polished sections were prepared. The micro-fabrics were investigated using scanning electron microscopy (SEM) and image analysis. Backscattered electron (BSE) images were used for the image analysis because carbonates can be extracted by grey level analysis. The image analysis of the extracted particles provides the following parameters: area, longest and shortest axis of an ellipse (surrounding the particle), perimeter, the angle to horizontal (longest axis), and the aspect ratio (longest axis/shortest axis). Callovo-Oxfordian clay stone shows a homogenous distribution of fine-grained carbonates and dovetail connection of calcium carbonate with the clayey matrix. In contrast Opalinus Clay shows large elongated carbonate grains (high aspect ratios) of shell fragments. Cracks are mostly related to these

Hydro-mechanical aspects: glacial loading/erosion - the opalinus clay study

International Nuclear Information System (INIS)

Marschall, P.; Kupfer, T.; Kuhlmann, U.

2004-01-01

In Nagra's high level waste programme the future geological evolution of the investigation area in the Zurcher Weinland (NE Switzerland) is considered over a time period of around 1 Ma. Uplift, erosion and climatic changes were identified as processes that may affect the long-term performance of a repository for spent fuel (SF), vitrified high-level waste (HLW) and long-lived intermediate-level waste (ILW). The possible impact of those long-term processes on the barrier function of the host rock formation (Opalinus Clay) comprises: (i) the change of the vertical hydraulic gradient caused by changing recharge/discharge conditions in the regional aquifer systems; (ii) permeability enhancement of the host rock formation due to the uplift process; and (iii) expulsion of contaminated pore water from the disposal area as a result of repeated glacial loading. Due to the fact that the discharge level of the regional aquifer systems is defined by the Rhine valley and the regional recharge areas are characterised by moderate elevations (typically 2 are not expected within the next several million years. Hence, the topography of NE Switzerland together with the favourable hydraulic properties of the host rock formation prevent efficiently the vertical exchange of groundwater between the regional aquifer systems. Even on geological time scales of millions of years the expected vertical pore water flow through the host rock formation is in the order of 10 -14 m/s and lower. At present, the Opalinus Clay forms a perfect hydraulic barrier. The process of ongoing uplift, however, may give rise to embrittlement of the rock, entailed by permeability enhancement. Evidence for permeability enhancement of Opalinus Clay in shallow depth was observed by Hekel (1994). On the other hand, regional studies confirmed the low permeability of the Opalinus Clay formation in greater depth even when fractured (Gautschi, 2001; Marschall et al., 2003). Such evidence, together with conceptual

Applications of flow visualization to the development of an innovative boom system

International Nuclear Information System (INIS)

Wong, K.F.V.; Wolek, A.

1996-01-01

A new oil retention boom system design was developed using a flow visualization technique. Hydrogen bubbles were generated on a fine wire cathode and placed in a stream of moving water with a strong light source to visualize the flow. Observations were made of the flow patterns around some basic shapes and booms modelled as cylinders with and without a skirt. The most effective system design had two booms with skirts in parallel with a submerged airfoil designed to cause the oil to separate and recirculate. Oil was allowed to flow above the airfoil into the recirculation region between the two floating booms. The new system is expected to outperform the conventional boom system only when flow velocity is high. Its most successful application would be in situations where flow is perpendicular to the length of the boom. 1 ref., 6 figs

Far Field Sorption Data Bases for Performance Assessment of a High-Level Radioactive Waste Repository in an Undisturbed Opalinus Clay Host Rock

Energy Technology Data Exchange (ETDEWEB)

Bradburry, M.; Baeyens, B

2003-08-01

An Opalinus Clay formation in the Zuercher Weinland is under consideration by Nagra as a potential location for a high-level and long-Iived intermediate-level radioactive waste repository. Performance assessment studies will be performed for this site and the purpose of this report is to describe the procedures used to develop sorption data bases appropriate for an undisturbed Opalinus Clay host rock which are required for such safety analysis calculations. In tight, low water content argillaceous rock formations such as Opalinus Clay, there is uncertainty concerning the in situ pH/P{sub CO{sub 2}}. In order to take this intrinsic uncertainty into account porewater chemistries were calculated for a reference case, pH = 7.24, and for two other pH values, 6.3 and 7.8. Sorption data bases are given for the three cases. The basis for the sorption data bases is 'in-house' sorption measurements for Cs(I), Sr(II), Ni(II), Eu(III), Sn(IV), Se(IV), Th(IV) and I(-I) carried out on Opalinus Clay samples from Mont Terri (Canton Jura) since at the time the experiments were performed no core samples from the Benken borehole (Zuercher Weinland) were available. The Opalinus Clay at Mont Terri and Benken are part of the same geological formation . Despite having directly measured data for the above key radionuclides, some of the required distribution ratios (Rd) used to generate the sorption data bases still came from the open literature. An important part of this report is concerned with describing the procedures whereby these selected literature Rd values were modified so as to apply to the Benken Opalinus Clay mineralogy and groundwater chemistries calculated at the three pH values given above. The resulting Rd values were then further modified using so-called Lab{yields}Field transfer factors to produce sorption values which were appropriate to the in situ bulk rock for the selected range of water chemistry conditions. Finally, it is important to have some

Evaluation of Used Fuel Disposition in Clay-Bearing Rock

Energy Technology Data Exchange (ETDEWEB)

Jove-Colon, Carlos F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Weck, Philippe F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hammond, Glenn Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kim, Kunhwi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, James [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Caporuscio, Florie Andre [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cheshire, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Palaich, Sarah [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Norskog, Katherine E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wolery, Thomas J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, Terry [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, William L. [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-04

Deep geological disposal of nuclear waste in clay/shale/argillaceous rock formations has received much consideration given its desirable attributes such as isolation properties (low permeability), geochemically reduced conditions, slow diffusion, sorbtive mineralogy, and geologically widespread (Jové Colón et al., 2014). There is a wealth of gained scientific expertise on the behavior of clay/shale/ argillaceous rock given its focus in international nuclear waste repository programs that includes underground research laboratories (URLs) in Switzerland, France, Belgium, and Japan. Jové Colón et al. (2014) have described some of these investigative efforts in clay rock ranging from site characterization to research on the engineered barrier system (EBS). Evaluations of disposal options that include nuclear waste disposition in clay/shale/argillaceous rock have determined that this host media can accommodate a wide range of waste types. R&D work within the Used Fuel Disposition Campaign (UFDC) assessing thermal effects and fluid-mineral interactions for the disposition of heat-generating waste have so far demonstrated the feasibility for the EBS and clay host rock to withstand high thermal loads. This report represents the continuation of disposal R&D efforts on the advancement and refinement of coupled Thermal-Hydrological-Mechanical-Chemical (THMC), hydrothermal experiments on clay interactions, used fuel degradation (source term), and thermodynamic modeling and database development. The development and implementation of a clay/shale/argillite reference case described in Jové Colón et al. (2014) for FY15 will be documented in another report (Mariner et al. 2015) – only a brief description will be given here. This clay reference case implementation is the result of integration efforts between the GDSA PA and disposal in argillite work packages. The assessment of sacrificial zones in the EBS is being addressed through experimental work along with 1D reactive

RD and D steering of a geological disposal programme in poorly indurated clays - ONDRAF/NIRAS example

International Nuclear Information System (INIS)

Van Geet, M.; Capouet, M.; Depaus, C.; Lalieux, P.

2012-01-01

Document available in extended abstract form only. For more than thirty years, Belgium has been investigating clay formations for its potential suitability to host a geological disposal. The R and D programme initiated as early as 1974 by the Belgian Nuclear Research Centre (SCK.CEN) at Mol was pursued from the early 1980's under ONDRAF/NIRAS' responsibility. These studies quickly focused on the Boom Clay formation at Mol-Dessel, in northeastern Belgium, as a potential host formation for a geological repository. The state of scientific and technical research on the possible disposal of high-and intermediate level radioactive waste (B and C waste) in clay layers was presented in decanal safety assessment reports and internationally reviewed. Over time, geological disposal in Boom Clay has progressively become the reference solution of ONDRAF/NIRAS for the long-term management of category B and C wastes, geological disposal in Ypresian Clays being considered as an alternative solution. The national and international peer review of the second Safety and Feasibility interim report (SAFIR 2) acknowledged in 2001 the maturity of the Belgian scientific program and endorsed ONDRAF/NIRAS conclusion to pursue the RD and D program on poorly indurated clays. Consequently, the NEA International Review Team urged ONDRAF/NIRAS to move on to the implementation phase while pursuing RD and D necessary to reduce the remaining uncertainties. This major step required ONDRAF/NIRAS to develop the frame and tools to embed its national program in a societal dialogue and in a stepwise decision-making plan with key milestones stretching over the next decades towards the licensing process. To serve these ends, ONDRAF/NIRAS has reassessed the organization of its geological disposal program. A strategy had to be set out to frame and formalize the stepwise and iterative development of a geological disposal in a coherent and integrating manner. Indeed, firstly, the maturity of the program had led

Shuttle sonic boom - Technology and predictions. [environmental impact

Science.gov (United States)

Holloway, P. F.; Wilhold, G. A.; Jones, J. H.; Garcia, F., Jr.; Hicks, R. M.

1973-01-01

Because the shuttle differs significantly in both geometric and operational characteristics from conventional supersonic aircraft, estimation of sonic boom characteristics required a new technology base. The prediction procedures thus developed are reviewed. Flight measurements obtained for both the ascent and entry phases of the Apollo 15 and 16 and for the ascent phase only of the Apollo 17 missions are presented which verify the techniques established for application to shuttle. Results of extensive analysis of the sonic boom overpressure characteristics completed to date are presented which indicate that this factor of the shuttle's environmental impact is predictable, localized, of short duration and acceptable. Efforts are continuing to define the shuttle sonic boom characteristics to a fine level of detail based on the final system design.

High-Speed Research: 1994 Sonic Boom Workshop. Configuration, Design, Analysis and Testing

Science.gov (United States)

McCurdy, David A. (Editor)

1999-01-01

The third High-Speed Research Sonic Boom Workshop was held at NASA Langley Research Center on June 1-3, 1994. The purpose of this workshop was to provide a forum for Government, industry, and university participants to present and discuss progress in their research. The workshop was organized into sessions dealing with atmospheric propagation; acceptability studies; and configuration design, and testing. Attendance at the workshop was by invitation only. The workshop proceedings include papers on design, analysis, and testing of low-boom high-speed civil transport configurations and experimental techniques for measuring sonic booms. Significant progress is noted in these areas in the time since the previous workshop a year earlier. The papers include preliminary results of sonic boom wind tunnel tests conducted during 1993 and 1994 on several low-boom designs. Results of a mission performance analysis of all low-boom designs are also included. Two experimental methods for measuring near-field signatures of airplanes in flight are reported.

USAF Flight Test Investigation of Focused Sonic Booms: Project Have Bears

Science.gov (United States)

Downing, Micah; Zamot, Noel; Moss, Chris; Morin, Daniel; Wolski, Ed; Chung, Sukhwan; Plotkin, Kenneth; Maglieri, Domenic

1996-01-01

Supersonic operations from military aircraft generate sonic booms that can affect people, animals and structures. A substantial experimental data base exists on sonic booms for aircraft in steady flight and confidence in the predictive techniques has been established. All the focus sonic boom data that are in existence today were collected during the 60's and 70's as part of the information base to the US Supersonic Transport program and the French Jericho studies for the Concorde. These experiments formed the data base to develop sonic boom propagation and prediction theories for focusing. There is a renewed interest in high-speed transports for civilian application. Moreover, today's fighter aircraft have better performance capabilities, and supersonic flights ars more common during air combat maneuvers. Most of the existing data on focus booms are related to high-speed civil operations such as transitional linear accelerations and mild turns. However, military aircraft operating in training areas perform more drastic maneuvers such as dives and high-g turns. An update and confirmation of USAF prediction capabilities is required to demonstrate the ability to predict and control sonic boom impacts, especially those produced by air combat maneuvers.

Do scaly clays control seismicity on faulted shale rocks?

Science.gov (United States)

Orellana, Luis Felipe; Scuderi, Marco M.; Collettini, Cristiano; Violay, Marie

2018-04-01

One of the major challenges regarding the disposal of radioactive waste in geological formations is to ensure isolation of radioactive contamination from the environment and the population. Shales are suitable candidates as geological barriers. However, the presence of tectonic faults within clay formations put the long-term safety of geological repositories into question. In this study, we carry out frictional experiments on intact samples of Opalinus Clay, i.e. the host rock for nuclear waste storage in Switzerland. We report experimental evidence suggesting that scaly clays form at low normal stress (≤20 MPa), at sub-seismic velocities (≤300 μm/s) and is related to pre-existing bedding planes with an ongoing process where frictional sliding is the controlling deformation mechanism. We have found that scaly clays show a velocity-weakening and -strengthening behaviour, low frictional strength, and poor re-strengthening over time, conditions required to allow the potential nucleation and propagation of earthquakes within the scaly clays portion of the formation. The strong similarities between the microstructures of natural and experimental scaly clays suggest important implications for the slip behaviour of shallow faults in shales. If natural and anthropogenic perturbations modify the stress conditions of the fault zone, earthquakes might have the potential to nucleate within zones of scaly clays controlling the seismicity of the clay-rich tectonic system, thus, potentially compromising the long-term safeness of geological repositories situated in shales.

Hydroxyapatite clay for gap filling and adequate bone ingrowth.

Science.gov (United States)

Maruyama, M; Terayama, K; Ito, M; Takei, T; Kitagawa, E

1995-03-01

In uncemented total hip arthroplasty, a complete filling of the gap between femoral prosthesis and the host bone is difficult and defects would remain, because the anatomy of the reamed intramedullary canal cannot fit the prosthesis. Therefore, it seems practical to fill the gap with a clay containing hydroxyapatite (HA), which has an osteoconductive character. The clay (HA clay) is made by mixing HA granules (size 0.1 mm or more) having a homogeneous pore distribution and a porosity of 35-48 vol%, and a viscous substance such as a saline solution of sodium alginate (SSSA). In the first experiment, the ratio of HA granules and sodium alginate in SSSA is set for the same handling properties of HA clay and polymethylmethacrylate bone cement (standard viscosity) before hardening. As a result, the ratio is set for 55 wt% of HA in the clay and 12.5 wt% of sodium alginate in SSSA (i.e., HA:sodium alginate:saline solution = 9.8:1:7). In the second study, the gap between the femoral stem and bone model is completely filled with HA clay. However, the gap is not filled only with HA granules or HA granules mixed with saline solution. In the third animal experiment, using an unloaded model, histology shows that HA clay has an osteoconductive property bridging the gap between the implant and the cortical bone without any adverse reaction. HA clay is considered a useful biomaterial to fill the gap with adequate bone ingrowth.

Sonic boom predictions using a modified Euler code

Science.gov (United States)

Siclari, Michael J.

1992-04-01

The environmental impact of a next generation fleet of high-speed civil transports (HSCT) is of great concern in the evaluation of the commercial development of such a transport. One of the potential environmental impacts of a high speed civilian transport is the sonic boom generated by the aircraft and its effects on the population, wildlife, and structures in the vicinity of its flight path. If an HSCT aircraft is restricted from flying overland routes due to excessive booms, the commercial feasibility of such a venture may be questionable. NASA has taken the lead in evaluating and resolving the issues surrounding the development of a high speed civilian transport through its High-Speed Research Program (HSRP). The present paper discusses the usage of a Computational Fluid Dynamics (CFD) nonlinear code in predicting the pressure signature and ultimately the sonic boom generated by a high speed civilian transport. NASA had designed, built, and wind tunnel tested two low boom configurations for flight at Mach 2 and Mach 3. Experimental data was taken at several distances from these models up to a body length from the axis of the aircraft. The near field experimental data serves as a test bed for computational fluid dynamic codes in evaluating their accuracy and reliability for predicting the behavior of future HSCT designs. Sonic boom prediction methodology exists which is based on modified linear theory. These methods can be used reliably if near field signatures are available at distances from the aircraft where nonlinear and three dimensional effects have diminished in importance. Up to the present time, the only reliable method to obtain this data was via the wind tunnel with costly model construction and testing. It is the intent of the present paper to apply a modified three dimensional Euler code to predict the near field signatures of the two low boom configurations recently tested by NASA.

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

International Nuclear Information System (INIS)

Minkley, W.; Popp, T.; Salzer, K.; Gruner, M.; Boettge, V.

2010-01-01

Document available in extended abstract form only. Long-term storage of high-level radioactive waste in deep geologic formations is worldwide the only accepted solution to warranty long term safety. Besides clay and crystalline rocks, salt is one of the potential host-rock candidates, mainly favored in Germany. As salts rocks are highly soluble their barrier integrity against water inflow from the cap rock is questionable. Argillaceous cap rocks or intercalated clay layers may act as protective shield in the hanging wall above a repository, thus providing a multi-barrier system. The aims of our study are twofold: 1) to characterize the mineralogical, hydraulic and rock-mechanical properties of the so-called Red Salt Clay (T4) as natural analogue of a clay barriers represented by different states of induration corresponding to various depth of burial diagenesis; 2) to demonstrate the favoured barrier properties of an argillaceous layer in the top of a salt formation undergoing dynamic processes such as rock bursts. The so-called Red Salt Clay (T4) is deposited as clay rich clastic sediment at the base of the Aller-series forming a persistent lateral layer above the lower Zechstein-series. The thickness of the clay-formation becomes smaller with decreasing distance from the border of the basin, i.e. from ∼15 m at Rossleben, over 7 m at Bernburg to 3.5 m at Zielitz, all in Saxony-Anhalt, D). The mineralogical composition of the Red Salt Clay varies, e.g. average composition for the Teutschenthal area: clay minerals 54% (Chlorite: 8%; Illite/Muscovite: 46%); quartz: 22%; anhydrite: 15%; accessory gypsum; Halite: 6%, Hematite: ∼ 2%). The geochemical and mineralogical composition of the Red Salt Clay represents a final state of natural salt-clay-systems, thus standing as a natural analogue for bentonite-based sealing systems in contact with high-saline solutions (e.g. saturated NaCl-solution, solutions with various Mg 2+ -, K + -, SO 4 2- - concentrations). The

Mineralogical and Micro-fabric investigation of the Sandy Facies of Opalinus Clay (Mont Terri)

International Nuclear Information System (INIS)

Kaufhold, Annette; Siegesmund, Siegfried; Dohrmann, Reiner; Graesle, Werner; Plischke, Ingo

2013-01-01

In the field of geological disposal of radioactive waste in many countries argillaceous formations are considered as potential host rock. For the understanding of the long-term behaviour of clay host rock, it is important to understand the interaction between mechanical behaviour, micro-fabric, and mineral composition. Previous publications showed that particularly the carbonate content and the arrangement of the carbonate grains (as cement in the matrix or as shells) determines the mechanical strength of Opalinus Clay and Callovo-Oxfordian Clay specimens, respectively. Klinkenberg et al. (2009) studied the shaly facies of Opalinus Clay, however, the actual deposit is planned to be built in the sandy facies of Opalinus Clay. The aim of the present study is to investigate the relation between micro-fabric, mineral composition, and mechanical properties of different samples derived from the sandy facies (BLT-A2). Image analysis showed that the carbonates in the sandy facies mainly occur as 1) matrix which in turn acts as cement. Carbonates also occur 2) in the fine sand fraction and 3) biogenic carbonates as traces. The carbonates of the sandy facies, therefore, appear to be similar to the carbonates of the Callovo-Oxfordian Clay with respect to their possible influence on failure strength. The mechanical testing showed that the shear strength increases with increasing carbonate content. This phenomenon was also observed for the samples of the Callovo-Oxfordian Clay, while the opposite relation was found for the shaly facies of the Opalinus Clay. Preliminary results presented here, indicate that the sandy facies (drilling BLT-A2) and Callovo-Oxfordian Clay show similar mechanical properties - in detail: 1) Micro-fabric: carbonates predominate in the matrix, 2) Mineralogy: high carbonate content and 3) Mechanical testing: shear strength increases with increasing carbonate content, where the type of carbonates which controls the increase of strength has to be

Boom Booom Net Radio

DEFF Research Database (Denmark)

Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

1999-01-01

of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

Enzymes activities involving bacterial cytochromes incorporated in clays

International Nuclear Information System (INIS)

Lojou, E.; Giudici-Orticoni, M.Th.; Bianco, P.

2005-01-01

With the development of bio electrochemistry, researches appeared on the enzymes immobilization at the surface of electrodes for the realization of bioreactors and bio sensors. One of the main challenges is the development of host matrix able to immobilize the protein material preserving its integrity. In this framework the authors developed graphite electrodes modified by clay films. These electrodes are examined for two enzyme reactions involving proteins of sulfate-reduction bacteria. Then in the framework of the hydrogen biological production and bioreactors for the environmental pollution de-pollution, the electrochemical behavior of the cytochrome c3 in two different clays deposed at the electrode is examined

Managing Credit Booms and Busts : A Pigouvian Taxation Approach

NARCIS (Netherlands)

Jeanne, O.; Korinek, A.

2010-01-01

We study a dynamic model in which the interaction between debt ac- cumulation and asset prices magni es credit booms and busts. We find that borrowers do not internalize these feedback e¤ects and therefore suf- fer from excessively large booms and busts in both credit flows and asset prices. We show

Inlet Trade Study for a Low-Boom Aircraft Demonstrator

Science.gov (United States)

Heath, Christopher M.; Slater, John W.; Rallabhandi, Sriram K.

2016-01-01

Propulsion integration for low-boom supersonic aircraft requires careful inlet selection, placement, and tailoring to achieve acceptable propulsive and aerodynamic performance, without compromising vehicle sonic boom loudness levels. In this investigation, an inward-turning streamline-traced and axisymmetric spike inlet are designed and independently installed on a conceptual low-boom supersonic demonstrator aircraft. The airframe was pre-shaped to achieve a target ground under-track loudness of 76.4 PLdB at cruise using an adjoint-based design optimization process. Aircraft and inlet performance characteristics were obtained by solution of the steady-state Reynolds-averaged Navier-Stokes equations. Isolated cruise inlet performance including total pressure recovery and distortion were computed and compared against installed inlet performance metrics. Evaluation of vehicle near-field pressure signatures, along with under- and off-track propagated loudness levels is also reported. Results indicate the integrated axisymmetric spike design offers higher inlet pressure recovery, lower fan distortion, and reduced sonic boom. The vehicle with streamline-traced inlet exhibits lower external wave drag, which translates to a higher lift-to-drag ratio and increased range capability.

Bust without boom.

Science.gov (United States)

Goldzieher, J W

2000-01-01

Just like injectables, oral contraceptives (OCs), including progestin-only ¿minipill¿ and ¿morning-after¿ pill regimens, have experienced a bust without a boom. Fear of political and religious backlash over emergency contraceptives containing estrogen and progestin prompted large companies not to market these regimens. Another major factor in the bust phase of OC use and acceptance has been a small coterie of English and American epidemiologists focused on the adverse effects of Ocs, including risks of thrombotic events, heart attacks, and strokes. The media played a crucial role in the bust phase of these OCs. In the UK, the alleged increase of cancer risk with pill use, which leaked before publication in London newspapers, resulted in 50,000 additional unintended pregnancies. Nevertheless, there is no doubt that boom-and-bust cycles will continue simply because many of the actors in this drama have too great a vested interest to desist. Groups involved in this field must recognize the hazards that come with the territory and be proactive, anticipatory, and well armed with facts--and get good with media access. Drug companies should think on a long-term basis the potential effects of leaving the field, as they have done, or shooting down competitive innovations.

Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

Science.gov (United States)

Bui, Trong

2010-01-01

An axisymmetric full Navier-Stokes computational fluid dynamics (CFD) study was conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock (LaNCETS) research airplane, was considered. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature, similar to what was observed in the LaNCETS flight data, is observed for the highly underexpanded nozzle flow. The CFD results provide a detailed description of the nozzle flow physics involved in the LaNCETS nozzle at different nozzle expansion conditions and help in interpreting LaNCETS flight data as well as in the eventual CFD analysis of a full LaNCETS aircraft. The current study also provided important information on proper modeling of the LaNCETS aircraft nozzle. The primary objective of the current CFD research effort was to support the LaNCETS flight research data analysis effort by studying the detailed nozzle exhaust jet plume s imperfect expansion effects on the sonic boom signature of a supersonic aircraft. Figure 1 illustrates the primary flow physics present in the interaction between the exhaust jet plume shock and the sonic boom coming off of an axisymmetric body in supersonic flight. The steeper tail shock from highly expanded jet plume reduces the dip of the sonic boom N-wave signature. A structured finite-volume compressible full Navier-Stokes CFD code was used in the current study. This approach is not limited by the simplifying assumptions inherent in previous sonic boom analysis efforts. Also, this study was the first known jet plume sonic boom CFD study in which the full viscous nozzle flow field was modeled, without

Study of Different Argillaceous Formations Performed in the Context of the FUNMIG project

Energy Technology Data Exchange (ETDEWEB)

Fernandez, A. M.; Melon, A.; Sanchez, D. M.; Gaucher, E.; Tournassat, C.; Altmann, S.C.; Vinsot, A.; Maes, N.; Craen, M. de; Leupin, O.; Wersin, P.; Astudillo, J.

2010-07-01

Argillaceous Rock Formations of low permeability have been selected in several countries as potential geological host rock for the disposal of high level radioactive wastes (HLRW). The general barrier function of the host rock is to retard and attenuate the migration of radionuclides to the biosphere, and the properties of clay minerals sustain this barrier functions. Nowadays, a number of Underground Research Laboratories (URL) have been constructed for a more in depth investigation of the indurated as well as plastic clay rock formations indifferent countries. The HADES under ground research facility (URF) was constructed at Mol (Belgium), where the Boom Clay formation is being studied as a reference host rock formation. The Opalinus Clay formation has been studied in the Mont Terri Rock Laboratory (Switzerland). The Callovo- Oxfordian clayrock is being characterised in the Meuse/Haute-Marne Site at Bure (France). The Boda Claystone is being analysed at Mecsek in Hungary. The knowledge on biogeochemical processes which affect the transport of radionuclides through the geosphere is a key parameter for the safety case of a HLRW repository, which was the aim of the EC Project FUNMIG: Fundamental Processes of Radionuclide Migration. The main factors controlling the mobility of the radionuclides are the chemistry of the pore water, the chemical reactions involving the radionuclides and the sorption processes on clay minerals. There fore, the pore water chemistry plays an important role in determining radionuclide migration characteristics in clay-rock formations. (Author)

Raw material boom in an industrial country. Rohstoffboom in einem Industrieland

Energy Technology Data Exchange (ETDEWEB)

Enders, K S

1984-01-01

First of all, a theoretical investigation is carried out to discover under which conditions a raw material boom displaces traditional sectors of industry, and which groups win and lose in the process. Subsequently, the peculiarities of the adaption process induced by the boom are analysed. Particular attention is paid to the possibility of transition (short-term) unemployment (Dutch disease). In conclusion, Norway's experiences in the oil and gas boom in the North Sea ar described and then compared with theoretical statements.

Strengthening and stress relaxation of Opalinus Clay

International Nuclear Information System (INIS)

Schulze, Otto

2010-01-01

Document available in extended abstract form only. Full text follows: In the framework of the EU-project NF-PRO (e.g. RTDC-5, Synthesis Report, D-No 5.2.3), special emphasis was put on the investigation and modelling of near-field processes in a candidate host rock: http://project.nf-pro.org/workspaces/rtdc5/deliverables/d5_2_3_rtdc_5_synthesis_report_final_version. The coupled TMHC-processes under consideration mainly concern the interaction between the host rock in and near to the EDZ and the waste products in its immediate vicinity. With respect to long-term safety analyses, there is no doubt that a sound process understanding is required. However, safe disposal also requires a suitable multi-barrier-system. This has to consist of technical and geo-technical barriers (e.g. container and backfill) but also of a strong geological barrier. Comparing the self-sealing capacity of the candidate host rocks, i.e. salt, clay and crystalline rock formations, where underground rooms will be inevitably backfilled only in part for technical reasons, in a salt formation convergence by viscous deformation provokes the re-establishing of a tight system, whereas in a crystalline rock formation long-term isolation has to be guaranteed solely by the technical and geotechnical components. This work is concentrated on the question, whether convergence and reduction of open space by long-term creep will take place also in a clay-stone formation, where laboratory investigation on Opalinus Clay from the Mont Terri Rock Laboratory was performed for this purpose. Several results from the work on the long-term deformation behaviour of clay-stone exist already. Nevertheless, to the author's knowledge the sound proof of a time-dependent and non-dilatant viscous deformation in the undisturbed far-field of clay-stone is still missing. Results from the rock laboratory at the Mt. Terri site yield hints for an anisotropic state of in-situ stresses, which may continue to exist in the

Flow distortion on boom mounted cup anemometers

DEFF Research Database (Denmark)

Lindelöw, Per Jonas Petter; Friis Pedersen, Troels; Gottschall, Julia

In this report we investigate on wind direction dependent errors in the measurement of the horizontal wind speed by boom mounted cup anemometers. The boom mounting on the studied lattice tower is performed according to IEC standard design rules, yet, larger deviations than predicted by flow models...... are observed. The errors on the measurements are likely caused by an underestimation of the flow distortions around the tower. In this paper an experimental method for deriving a correction formula and an in-field calibration is suggested. The method is based on measurements with two cup anemometers mounted...

Waste Disposal: Processes Taking Place (on the way) from the Repository to the Biosphere

International Nuclear Information System (INIS)

Put, M.

2000-01-01

The main objective of SCK-CEN's R and D programme on the processes taking place on the way from the repository to the biosphere is to provide reliable and defensible models and parameters on the migration of dissolved radionuclides and gases through the host formation (Boom Clay) and the backfill materials of a deep geological repository for high level radioactive waste. The programme and main achievements in this topical area in 1999 are summarised

Review of Studies of Clay Minerals as Significant Component of Potential Host Rocks or Engineering Barriers for Radioactive Waste Disposals Performed at Comenius University in Bratislava

International Nuclear Information System (INIS)

Peter, Uhlik; Vladimir, Sucha; Maria, Caplovicova; Igor, Stricek

2013-01-01

About 50 % of electric power is produced by nuclear power plants in Slovakia. In spite of the significant production of nuclear waste, Slovakia has not defined basic strategy of radioactive-waste isolation. However, some pilot projects and studies have been carried out. Five areas were determined as prospective sites for construction of deep geological repository (DGR). Two of them are situated in the south of Slovakia. Szecseny schlier (mixture of siltstones and Clay-stones) of Lucenec Formation (Egerian) is one of the most prospective host rocks from lithological, structural and spatial perspective. Besides the investigation of potential host rock for DGR the studies of bentonite properties as important part of engineering barriers for radioactive waste disposals were performed. Detailed mineral and structural analyses of smectites from the bentonitic material exposed to laboratory Mock-Up test were realised. Particular interest has been focused on interaction between Fe and smectites. Other field of interest is investigation of sorption of Cs and Sr on natural and modified bentonites, including irradiation. Purpose of this work is to present a short review of other studies done by our group with partial focusing to interaction of organic dye (Rhoda-mine 6G) with smectite that is connected with changes of layer charge after treatment; possibilities to measure preferential orientation of clays after compaction by TEM and to effort to use X-ray micro-tomography for inner structure of sediments. (authors)

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

International Nuclear Information System (INIS)

Altmann, S.; Aertsens, M.; Appelo, T.; Bruggeman, C.; Gaboreau, S.; Glaus, M.; Jacquier, P.; Kupcik, T.; Maes, N.; Montoya, V.; Rabung, T.; Robinet, J.-C.; Savoye, S.; Schaefer, T.; Tournassat, C.; Van Laer, L.; Van Loon, L.

2015-07-01

In the framework of the feasibility studies on the radioactive waste disposal in deep argillaceous formations, it is now well established that the transport properties of solutes in clay rocks, i.e. parameter values for Fick's law, are mainly governed by the negatively charged clay mineral surface. While a good understanding of the diffusive behaviour of non-reactive anionic and neutral species is now achieved, much effort has to be placed on improving understanding of coupled sorption/diffusion phenomena for sorbing cations. Indeed, several cations known to form highly stable surface complexes with sites on mineral surfaces migrate more deeply into clay rock than expected. Therefore, the overall objective of the EC CatClay project is to address this issue, using a 'bottom-up' approach, in which simpler, analogous systems (here a compacted clay, 'pure' illite) are experimentally studied and modelled, and then the transferability of these results to more complex materials, i.e. the clay rocks under consideration in France, Switzerland and Belgium for hosting radioactive waste disposal facilities, is verified. The cations of interest were chosen for covering a representative range of cations families: from a moderately sorbing cation, the strontium, to three strongly sorbing cations, Co(II), Zn(II) and Eu(III). For the 4 years of this project, much effort was devoted to developing and applying specific experimental methods needed for acquiring the high precision, reliable data needed to test the alternative hypotheses represented by different conceptual-numerical models. The enhanced diffusion of the sorbing cations of interest was confirmed both in the simpler analogous illite system for Sr 2+ , Co(II) and Zn(II), but also in the natural clay rocks, except for Eu(III). First modelling approach including diffusion in the diffuse double layer (DDL) promisingly succeeded in reproducing the experimental data under the various conditions both in

Sheath-Based Rollable Lenticular-Shaped and Low-Stiction Composite Boom

Science.gov (United States)

Fernandez, Juan M. (Inventor)

2018-01-01

Various embodiments provide rollable and deployable composite booms that may be used in a wide range of applications both for space and terrestrial structural solutions. Various embodiment composite booms may be bistable, i.e. having a stable strain energy minimum in the coiled configuration as well as the in the deployed configuration. In various embodiments, a boom may be fabricated by aligning two independent tape-springs front-to-front encircled by a durable seamless polymer sleeve. The durable seamless polymer sleeve may allow the two tape-springs to slide past each other during the coiling/deployment process so as to reduce, e.g., minimize, shear and its derived problems.

Clay membrane made of natural high plasticity clay

DEFF Research Database (Denmark)

Foged, Niels; Baumann, Jens

1998-01-01

Leachate containment in Denmark has through years been regulated by the DIF Recommendation for Sanitary Landfill Liners (DS/R 466). It states natural clay deposits may be used for membrane material provided the membrane and drainage system may contain at least 95% of all leachate created throughout...... ion transport as well as diffusion.Clay prospection for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island Lolland. The natural clay contains 60 to 75% smectite, dominantly as a sodium-type. The clay material...... has been evaluated using standardised methods related to mineralogy, classification, compaction and permeability, and initial studies of diffusion properties have been carried out. Furthermore, at a test site the construction methods for establishing a 0.15 to 0.3m thick clay membrane have been tested...

Clay membrane made of natural high plasticity clay:

DEFF Research Database (Denmark)

Foged, Niels; Baumann, Jens

1999-01-01

Leachate containment in Denmark has throughout the years been regulated by the DIF Recommendation for Sanitary Landfill Liners (DS/R4669. It states that natural clay deposits may be used as membrane material provided the membrane and drainage system contains at least 95% of all leachate created...... 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......-type. The clay material has been evaluated using the standardized methods related to mineralogy, classification, compaction and permeability, and initial studies of diffusion properties have been carried out. Furthermore, at a test site the construction methods for establishing a 0.15-0.3 m thick clay membrane...

Self-sealing of fractures in argillaceous formations - Evidence, mechanisms and implications for performance assesment (an NEA Clay Club project)

International Nuclear Information System (INIS)

Bock, H.; Dehandschutter, B.; Martin, C.D.; Mazurek, M.; Haller, A. de; Skoczylas, F.; Davy, C.

2010-01-01

Document available in extended abstract form only. After some earlier attempts dating back to the year 1999, the Self-Sealing Project of the Clay Club of the NEA/OECD was re-launched in 2007 and recently completed with the publication of NEA monograph No. 6184 (Bock et al., 2010). The project aimed at providing an overview and synthesis of the current understanding of, and conceptual approaches to, the processes that lead to self-sealing of natural and man-induced fractures in argillaceous formations at typical repository depths. The term 'self-sealing' relates to a phenomenon that fractured argillaceous formations tend to become, with the passage of time, less conductive to groundwater and finally hydraulically insignificant. It directly addresses the long-term functionality of the host rock as a migration barrier to radio-nuclides and it is often considered as one of the decisive factors favouring the choice of argillaceous formations as host rocks for deep disposals. In its outcome the project has significantly consolidated the evidence on self-sealing in argillaceous formations. It reconfirmed that self-sealing is a common phenomenon in a wide variety of argillaceous formations which are currently considered in context with deep geological repositories; from plastic clays (Boom Clay in the HADES URF) to moderately indurated clays (Opalinus Clay at Mont Terri and Callovo- Oxfordian argillites at the Meuse-Haute Marne URL). One of the most compelling evidence stems from the fact that self-sealing is observed over a large spread of scales in terms of length and time: At the millimetre to metre scale in laboratory testing, at the repository scale (10 m to 100 m range) in URL field tests and at the kilometre scale in geologic and geotechnical analogues such as traffic tunnels and hydrocarbon reservoirs. Over geological time scales, it is, for example, evidenced in the existence of hydraulically and geochemically inactive geological faults, in the existence

RD and D steering of a geological disposal programme in poorly indurated clays

International Nuclear Information System (INIS)

Capouet, M.; Depaus, C.; Van Geet, M.; Lalieux, P.

2014-01-01

For more than thirty years, Belgium has been investigating clay formations for its potential suitability to host a geological disposal. The R and D programme initiated as early as 1974 by the Belgian Nuclear Research Centre (SCK.CEN) at Mol was pursued from the early 1980's under ONDRAF/NIRAS' responsibility. These studies quickly focused on the Boom Clay formation at Mol-Dessel, in north-eastern Belgium, as a potential host formation for a geological repository. The state of scientific and technical research on the possible disposal of high- and intermediate-level radioactive waste (B and C waste) in clay layers was presented in decennial safety assessment reports. The national and international peer review of the second Safety and Feasibility interim report SAFIR 2 acknowledged the maturity of the Belgian scientific programme and endorsed ONDRAF/NIRAS' conclusion to pursue the RD and D programme associated with a safe and feasible geological disposal in poorly indurated clays. Next to the continuing necessity of RD and D in all relevant areas of the Belgian programme, the NEA International Review Team (IRT) highlighted three main areas of activity that ONDRAF/NIRAS should strengthen to move on to the implementation phase. First, the IRT acknowledged the novel and innovative methodological concepts (i.e. safety functions, alternative safety indicators) introduced in its programme and recommended that ONDRAF/NIRAS move forward in this direction and improve the methodology for a more systematic, consistent and comprehensive treatment of uncertainties. Secondly, the IRT recommended further development of the EBS. Understanding of the engineered component's behaviour, its physic-chemical evolution with its inter-dependencies with the other components, its feasibility as well as its performance was indeed limited at the time of SAFIR 2. Last, the maturity of the geological programme suggested that it was time to initiate a dialogue with the regulators, policy makers

Dynamic simulation of a planar flexible boom for tokamak in-vessel operations

International Nuclear Information System (INIS)

Ambrosino, G.; Celentano, G.; Garofalo, F.; Maisonnier, D.

1991-01-01

In this paper we present a dynamic model for the analysis of the vibrations of a planar articulated flexible boom to be used for tokamak in-vessel maintenance operations. The peculiarity of the mechanical structure of the boom enables us to consider separately the oscillations in the horizontal and vertical planes so that two separate models can be constructed for describing these phenomena. The results of simulations based on booms like that proposed for NET in-vessel operations are presented. (orig.)

Clay Play

Science.gov (United States)

Rogers, Liz; Steffan, Dana

2009-01-01

This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

The NET articulated boom: Preliminary investigations and justification for a full scale prototype

International Nuclear Information System (INIS)

Suppan, A.

1990-12-01

The articulated boom system is the favourite in-vessel handling system for NET which will be used to maintain or replace in-vessel components during short term interventions. The testbed EDITH is the prototype of this system and is the logical step between the proof of principle of the system, which is already performed by the JET articulated boom, and the operational equipment for NET. EDITH is required to demonstrate that maintenance of plasma facing components can be carried out with the anticipated reliability and time. To achieve this aim EDITH is based on the experience of the JET boom and will be constructed in full scale, supplemented by a full scale mock-up. A further goal of EDITH is to allow the testing of boom components and subassemblies. The results of preliminary investigations for the boom are summarized, the need of the testbed EDITH and a full scale mock-up is discussed and both EDITH and the mock-up are described. (orig.) [de

Ball clay

Science.gov (United States)

Virta, R.L.

2001-01-01

Part of the 2000 annual review of the industrial minerals sector. A general overview of the ball clay industry is provided. In 2000, sales of ball clay reached record levels, with sanitary ware and tile applications accounting for the largest sales. Ball clay production, consumption, prices, foreign trade, and industry news are summarized. The outlook for the ball clay industry is also outlined.

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

International Nuclear Information System (INIS)

Brookins, D.G.

1993-06-01

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

Influence of clay mineralogy on clay based ceramic products

International Nuclear Information System (INIS)

Radzali Othman; Tuan Besar Tuan Sarif; Zainal Arifin Ahmad; Ahmad Fauzi Mohd Noor; Abu Bakar Aramjat

1996-01-01

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

Diffusion Experiments with Opalinus and Callovo-Oxfordian Clays: Laboratory, Large-Scale Experiments and Microscale Analysis by RBS

International Nuclear Information System (INIS)

Garcia-Gutierrez, M.; Alonso, U.; Missana, T.; Cormenzana, J.L.; Mingarro, M.; Morejon, J.; Gil, P.

2009-01-01

Consolidated clays are potential host rocks for deep geological repositories for high-level radioactive waste. Diffusion is the main transport process for radionuclides (RN) in these clays. Radionuclide (RN) diffusion coefficients are the most important parameters for Performance Assessment (PA) calculations of clay barriers. Different diffusion methodologies were applied at a laboratory scale to analyse the diffusion behaviour of a wide range of RN. Main aims were to understand the transport properties of different RNs in two different clays and to contribute with feasible methodologies to improve in-situ diffusion experiments, using samples of larger scale. Classical laboratory essays and a novel experimental set-up for large-scale diffusion experiments were performed, together to a novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS), for diffusion analyses at the micrometer scale. The main experimental and theoretical characteristics of the different methodologies, and their advantages and limitations are here discussed. Experiments were performed with the Opalinus and the Callovo-Oxfordian clays. Both clays are studied as potential host rock for a repository. Effective diffusion coefficients ranged between 1.10 - 10 to 1.10 - 12 m 2 /s for neutral, low sorbing cations (as Na and Sr) and anions. Apparent diffusion coefficients for strongly sorbing elements, as Cs and Co, are in the order of 1.10-13 m 2 /s; europium present the lowest diffusion coefficient (5.10 - 15 m 2 /s). The results obtained by the different approaches gave a comprehensive database of diffusion coefficients for RN with different transport behaviour within both clays. (Author) 42 refs

MODEL CORRELATION STUDY OF A RETRACTABLE BOOM FOR A SOLAR SAIL SPACECRAFT

Science.gov (United States)

Adetona, O.; Keel, L. H.; Oakley, J. D.; Kappus, K.; Whorton, M. S.; Kim, Y. K.; Rakpczy, J. M.

2005-01-01

To realize design concepts, predict dynamic behavior and develop appropriate control strategies for high performance operation of a solar-sail spacecraft, we developed a simple analytical model that represents dynamic behavior of spacecraft with various sizes. Since motion of the vehicle is dominated by retractable booms that support the structure, our study concentrates on developing and validating a dynamic model of a long retractable boom. Extensive tests with various configurations were conducted for the 30 Meter, light-weight, retractable, lattice boom at NASA MSFC that is structurally and dynamically similar to those of a solar-sail spacecraft currently under construction. Experimental data were then compared with the corresponding response of the analytical model. Though mixed results were obtained, the analytical model emulates several key characteristics of the boom. The paper concludes with a detailed discussion of issues observed during the study.

Icelandic boom and bust - Immigration and the housing market

OpenAIRE

Lúðvík Elíasson

2014-01-01

Possible explanations for the rapid increase in house prices and housing investment in Iceland between 2004 and 2007 and the subsequent market crash are studied. The boom was driven in part by banking liberalisation, international financial conditions, and domestic policies. A simple demand and supply model, based on the study by Elíasson and Pétursson (2009), is fitted to data through the recent boom-bust period. The model is remarkably robust through the cycle despite its unprecedented ampl...

SPRAYED CLAY TECHNOLOGY FOR THE DEEP REPOSITORY OF HIGH-LEVEL RADIOACTIVE WASTE

Directory of Open Access Journals (Sweden)

Lucie Hausmannová

2012-07-01

Full Text Available The sealing barrier will play very important role in the Czech disposal concept of high level radioactive waste. It follows Swedish SKB3 design where granitic rock environment will host the repository. Swelling clay based materials as the most favorable for sealing purposes were selected. Such clays must fulfill certain requirements (e.g. on swelling properties, hydraulic conductivity or plasticity and must be stable for thousands of years. Better sealing behavior is obtained when the clay is compacted. Technology of the seal construction can vary according to its target dry density. Very high dry density is needed for buffer (sealing around entire canister with radioactive waste. Less strict requirements are on material backfilling the access galleries. It allows compaction to lower dry density than in case of buffer. One of potential technology for backfilling is to compact clay layers in most of the gallery profile by common compaction machines (rollers etc. and to spray clay into the uppermost part afterwards. The paper introduces the research works on sprayed clay technology performed at the Centre of Experimental Geotechnics of the Czech Technical University in Prague. Large scale in situ demonstration of filling of short drift in the Josef Gallery is also mentioned.

Modeling and simulation of the agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the application process. Thus we can guarantee the quality of the chemical droplets distribution on the crops. In this paper we design a sprayer boom leveling system for agricultural sprayer vehicles combined with a four-rod linkage self-leveling suspension and electro-hydraulic auto-leveling system. The dynamic analysis shows that the suspension can realize an excellent self-leveling in a comparative small inclination range. In addition we build compensation controller for the electro-hydraulic system based on the mathematical model. With simulations we can optimize the performance of this controller to make sure a fast leveling response to the inclined sprayer boom. © 2011 IEEE.

Clay club initiative: self-healing of fractures in clay-rich host rocks

International Nuclear Information System (INIS)

Horseman, S.T.; Cuss, R.J.; Reeves, H.J.

2004-01-01

The capacity of fractures in argillaceous rocks to self-heal (or become, with the passage of time, less conductive to groundwater) is often cited as a primary factor favouring the choice of such materials as host rocks for deep disposal. The underlying processes which contribute to self-healing can be broadly subdivided into: (a) mechanical and hydro-mechanical processes linked to the change in the stress field, movement of pore water, swelling, softening, plastic deformation and creep, and (b) geochemical processes linked to chemical alterations, transport in aqueous solution and the precipitation of minerals. Since chemical alteration can cause profound changes to the mechanical properties of argillaceous rocks, it is often difficult to draw a firm line between these two subdivisions. Based on the deliberations of the recent Cluster Conference in Luxembourg, there would appear to be some support for the use of the term 'self-sealing' for processes affecting fracture conductivity in argillaceous rock that are largely mechanical or hydro-mechanical in their origin. There are four main areas in which the self-healing capacity of the host rock becomes relevant to repository design and performance assessment: - potential for radionuclide transport within the excavation damage zone (EDZ); - design and performance of repository sealing systems; - potential impact of gas migration; - long-term performance considering erosional unloading, seismicity and fault reactivation. The presence of an EDZ is acknowledged to be a particularly important issue in performance assessment. Interconnection of fractures in the EDZ could lead to the development of a preferential flow path extending along the emplacement holes, access tunnels and shafts of a repository towards overlying aquifers and the biosphere. In the preliminary French Safety Analyses, for example, the treatment of scenarios relating to early seal failure have highlighted the hydraulic role of the damaged zone as a

Large scale laboratory diffusion experiments in clay rocks

International Nuclear Information System (INIS)

Garcia-Gutierrez, M.; Missana, T.; Mingarro, M.; Martin, P.L.; Cormenzana, J.L.

2005-01-01

Full text of publication follows: Clay formations are potential host rocks for high-level radioactive waste repositories. In clay materials the radionuclide diffusion is the main transport mechanism. Thus, the understanding of the diffusion processes and the determination of diffusion parameters in conditions as similar as possible to the real ones, are critical for the performance assessment of deep geological repository. Diffusion coefficients are mainly measured in the laboratory using small samples, after a preparation to fit into the diffusion cell. In addition, a few field tests are usually performed for confirming laboratory results, and analyse scale effects. In field or 'in situ' tests the experimental set-up usually includes the injection of a tracer diluted in reconstituted formation water into a packed off section of a borehole. Both experimental systems may produce artefacts in the determination of diffusion coefficients. In laboratory the preparation of the sample can generate structural change mainly if the consolidated clay have a layered fabric, and in field test the introduction of water could modify the properties of the saturated clay in the first few centimeters, just where radionuclide diffusion is expected to take place. In this work, a large scale laboratory diffusion experiment is proposed, using a large cylindrical sample of consolidated clay that can overcome the above mentioned problems. The tracers used were mixed with clay obtained by drilling a central hole, re-compacted into the hole at approximately the same density as the consolidated block and finally sealed. Neither additional treatment of the sample nor external monitoring are needed. After the experimental time needed for diffusion to take place (estimated by scoping calculations) the block was sampled to obtain a 3D distribution of the tracer concentration and the results were modelled. An additional advantage of the proposed configuration is that it could be used in 'in situ

Diffusion Experiments with Opalinus and Callovo-Oxfordian Clays: Laboratory, Large-Scale Experiments and Microscale Analysis by RBS

Energy Technology Data Exchange (ETDEWEB)

Garcia-Gutierrez, M.; Alonso, U.; Missana, T.; Cormenzana, J.L.; Mingarro, M.; Morejon, J.; Gil, P.

2009-09-25

Consolidated clays are potential host rocks for deep geological repositories for high-level radioactive waste. Diffusion is the main transport process for radionuclides (RN) in these clays. Radionuclide (RN) diffusion coefficients are the most important parameters for Performance Assessment (PA) calculations of clay barriers. Different diffusion methodologies were applied at a laboratory scale to analyse the diffusion behaviour of a wide range of RN. Main aims were to understand the transport properties of different RNs in two different clays and to contribute with feasible methodologies to improve in-situ diffusion experiments, using samples of larger scale. Classical laboratory essays and a novel experimental set-up for large-scale diffusion experiments were performed, together to a novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS), for diffusion analyses at the micrometer scale. The main experimental and theoretical characteristics of the different methodologies, and their advantages and limitations are here discussed. Experiments were performed with the Opalinus and the Callovo-Oxfordian clays. Both clays are studied as potential host rock for a repository. Effective diffusion coefficients ranged between 1.10{sup -}10 to 1.10{sup -}12 m{sup 2}/s for neutral, low sorbing cations (as Na and Sr) and anions. Apparent diffusion coefficients for strongly sorbing elements, as Cs and Co, are in the order of 1.10-13 m{sup 2}/s; europium present the lowest diffusion coefficient (5.10{sup -}15 m{sup 2}/s). The results obtained by the different approaches gave a comprehensive database of diffusion coefficients for RN with different transport behaviour within both clays. (Author) 42 refs.

A summary of the lateral cutoff analysis and results from NASA's Farfield Investigation of No-boom Thresholds

Science.gov (United States)

Cliatt, Larry J.; Hill, Michael A.; Haering, Edward A.; Arnac, Sarah R.

2015-10-01

In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, NASA, in partnership with other industry organizations, conducted a flight research experiment to analyze acoustic propagation at the lateral edge of the sonic boom carpet. The name of the effort was the Farfield Investigation of No-boom Thresholds (FaINT). The research from FaINT determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, established a value of 65 dB as a limit for the acoustic lateral extent of a sonic boom's noise region, analyzed change in sonic boom levels near lateral cutoff, and compared between real sonic boom measurements and numerical predictions.

Sobre o Boom e outras onomatopeias literárias

OpenAIRE

Londoño, Jorge Iván Parra

2016-01-01

Este artículo trata de examinar los alcances literarios del llamado Boom latinoamericano, a medio siglo de su estallido, las cuatro obras más representativas y sus respectivos autores, además de proponer un quinto autor, según la invitación que hiciera en su momento el crítico Ángel Rama. Por otro lado, evalua la respuesta literaria por parte del Post Boom, analizando sus características y su vigencia y, de manera concomitante, los movimientos anejos o posteriores a dicho movimiento, como el ...

Measuring and explaining the baby boom in the developed world in the mid-twentieth century

Directory of Open Access Journals (Sweden)

Jesús J. Sánchez-Barricarte

2018-03-01

Full Text Available Background: The early research on the baby boom tried to account for it as a logical recovery following the end of the Second World War (WWII. But it cannot be understood merely as a post-war phenomenon because its origins go back to the 1930s and early 1940s. Objective: I shall describe the methodology used to measure the total and marital baby boom and provide a detailed description of it. I shall attempt to explain the possible reasons that led to the sharp increase in the marital fertility rates and its subsequent decline. Methods: I will use various fertility indices that track the historical development of fertility (total and marital; period and cohort. Results: I show that there are major differences in the measurement of the baby boom depending on the index used. I found that the baby boom is highly heterogeneous in the 25 countries that form part of my study. It represented the logical response that families made to one period of prolonged political, economic, and military crisis (the crash of 1929 and WWII. Conclusions: Researchers who use only the total fertility indices are really analysing only the nuptiality boom, which took place during those years, rather than changes in reproductive behaviour. Contribution: I measure total and marital baby boom for 25 developed countries and perform the calculations to measure the impact of marital fertility and nuptiality on the total baby boom (TBB. I present a new explanation of the origins of the baby boom.

Design methodology for a community response questionnaire on sonic boom exposure

Science.gov (United States)

Farbry, John E., Jr.; Fields, James M.; Molino, John A.; Demiranda, Gwendolyn A.

1991-01-01

A preliminary draft questionnaire concerning community response to sonic booms was developed. Interviews were conducted in two communities that had experienced supersonic overflights of the SR-71 airplane for several years. Even though the overflights had ceased about 6 months prior to the interviews, people clearly remembered hearing sonic booms. A total of 22 people living in central Utah and 23 people living along Idaho/Washington state border took part in these interviews. The draft questionnaire was constantly modified during the study in order to evaluate different versions. Questions were developed which related to annoyance, startle, sleep disturbance, building vibration, and building damage. Based on the data collected, a proposed community response survey response instrument was developed for application in a full-scale sonic boom study.

Numerical Predictions of Sonic Boom Signatures for a Straight Line Segmented Leading Edge Model

Science.gov (United States)

Elmiligui, Alaa A.; Wilcox, Floyd J.; Cliff, Susan; Thomas, Scott

2012-01-01

A sonic boom wind tunnel test was conducted on a straight-line segmented leading edge (SLSLE) model in the NASA Langley 4- by 4- Foot Unitary Plan Wind Tunnel (UPWT). The purpose of the test was to determine whether accurate sonic boom measurements could be obtained while continuously moving the SLSLE model past a conical pressure probe. Sonic boom signatures were also obtained using the conventional move-pause data acquisition method for comparison. The continuous data acquisition approach allows for accurate signatures approximately 15 times faster than a move-pause technique. These successful results provide an incentive for future testing with greatly increased efficiency using the continuous model translation technique with the single probe to measure sonic boom signatures. Two widely used NASA codes, USM3D (Navier-Stokes) and CART3D-AERO (Euler, adjoint-based adaptive mesh), were used to compute off-body sonic boom pressure signatures of the SLSLE model at several different altitudes below the model at Mach 2.0. The computed pressure signatures compared well with wind tunnel data. The effect of the different altitude for signature extraction was evaluated by extrapolating the near field signatures to the ground and comparing pressure signatures and sonic boom loudness levels.

A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

Science.gov (United States)

Cliatt, Larry James; Haering, Ed; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

2014-01-01

In support of NASAs ongoing effort to bring supersonic commercial travel to the public, NASA Dryden Flight Research Center and NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response. Such tests will go towards building a dataset that governing agencies like the Federal Aviation Administration and International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. Until WSPR, there had never been an effort that studied the response of people in their own homes and performing daily activities to non-traditional, low sonic booms.WSPR was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle. Other partners included Gulfstream Aerospace Corporation, Pennsylvania State University, Tetra Tech, and Fidell Associates, Inc.A major objective of the effort included exposing a community with the sonic boom magnitudes and occurrences expected in high-air traffic regions with a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data was collected using multiple survey methods. The research focused on essential elements of community response testing including subject recruitment, survey methods, instrumentation systems, flight planning and operations, and data analysis methods.This paper focuses on NASAs role in the efforts

Migrant labor supply in a booming non-renewable resource economy: Cure and transmission mechanism for de-industrialization?

Science.gov (United States)

Nulle, Grant Mark

This paper challenges the determinism that booming resource economies suffer from de-industrialization, the "Dutch Disease". For several decades, economists have attempted to explain how a sudden surge in mineral and energy extraction affects an economy's output and employment from an aggregate and sectoral perspective. Economic theory shows that a "boom" in mineral and energy production is welfare enhancing to the economy experiencing it. However, the phenomenon also induces inter-sectoral adjustments among non-renewable resource (NRR), traditional traded, and non-traded industries that tend to crowd out traditional export sectors such as agriculture and manufacturing. In turn, this paper asks two fundamental questions: 1) Can the inter-sectoral adjustments wrought by a boom in NRR production be mitigated in the resource-abundant economy experiencing it; 2) Can the inter-sectoral adjustments be exported to a neighboring non-resource economy by movements in migrant labor supply? The theoretical model and empirical estimation approach presented in this paper introduces an endogenous migrant labor supply response to booms in NRR output to test the extent traditional tradable sectors shrink in the NRR-abundant economy during the boom and if such effects are exported to a neighboring jurisdiction. Using data at the U.S. county level, the empirical results show that booming economies experience positive and statistically significant rates of real income and traded sector job growth during the boom, attributable to the influx of migrant labor. By contrast, little evidence is found that non-booming counties adjacent to the booming counties experience declines in income or job growth because of labor supply outflows. Instead, the results suggest the larger the number of potential "donor" counties that can supply labor to the booming economies, the more likely the transmission of booming economy effects, namely evidence of de-industrialization, is diffused across all of the

Economic booms and risky sexual behavior: evidence from Zambian copper mining cities.

Science.gov (United States)

Wilson, Nicholas

2012-12-01

Existing studies suggest that individual and household level economic shocks affect the demand for and supply of risky sex. However, little evidence exists on the effects of an aggregate shock on equilibrium risky sexual behavior. This paper examines the effects of the early twenty-first century copper boom on risky sexual behavior in Zambian copper mining cities. The results suggest that the copper boom substantially reduced rates of transactional sex and multiple partnerships in copper mining cities. These effects were partly concentrated among young adults and copper boom induced in-migration to mining cities appears to have contributed to these reductions. Copyright © 2012. Published by Elsevier B.V.

Iron-clay interactions under a thermal gradient

International Nuclear Information System (INIS)

Jodin-Caumon, Marie-Camille; Mosser-Ruck, Regine; Randi, Aurelien; Cathelineau, Michel; Michau, Nicolas

2010-01-01

Document available in extended abstract form only. Repository in deep geological formations is considered as a possible solution for long-term high-level nuclear waste (HLW) management. The concept generally consists in a multiple barriers system including steel canister in a clay host rock. Heat and radiation emissions by HLW, corrosion of the canister and desaturation/re-saturation of the clay may affect the properties of the geological formation. In this context, the possible mineralogical evolutions of clays in contact with metal iron were studied in various conditions simulating those of HLW repository. Most of these studies were carried out at a constant temperature whereas the system will undergo a thermal gradient in time (progressive decrease of the temperature of the HLW with the decrease of its activity) and space (from the waste to the host rock). A thermal gradient may imply mass transport phenomena by convection and diffusion processes as a function of temperature, gradient intensity and the nature of the chemical elements. Here we show the effect of a thermal gradient in space on the interaction between the argillite from the ANDRA underground laboratory at Bure (Meuse/Haute-Marne) and metal iron. Tube-in-tube experiments were carried out. Argillite was put in two previously drilled platinum capsules (Diam. holes: 200 μm). Metal iron (powder and plate) was added in one of the Pt capsule. The Pt capsules were then loaded at the two ends of a gold tube. A fluid (H 2 O or a saline solution) was added and the gold tube was sealed and regularly pinched to form 5 precipitation niches. The iron/argillite mass ratio ranged between 0.3 and 0.5 and the fluid/argillite mass ratio was around 10. A thermal gradient 80 deg. C-150 deg. C or 150 deg. C-300 deg. C was applied to the tube during 3 and 6 months. The end of the gold tube with the Pt capsule containing iron was placed at the hot point (max. temperature 150 deg. C or 300 deg. C) or at the cold point (min

1995 NASA High-Speed Research Program Sonic Boom Workshop. Volume 2; Configuration Design, Analysis, and Testing

Science.gov (United States)

Baize, Daniel G. (Editor)

1999-01-01

The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Sonic Boom Workshop on September 12-13, 1995. The workshop was designed to bring together NASAs scientists and engineers and their counterparts in industry, other Government agencies, and academia working together in the sonic boom element of NASAs High-Speed Research Program. Specific objectives of this workshop were to: (1) report the progress and status of research in sonic boom propagation, acceptability, and design; (2) promote and disseminate this technology within the appropriate technical communities; (3) help promote synergy among the scientists working in the Program; and (4) identify technology pacing, the development C, of viable reduced-boom High-Speed Civil Transport concepts. The Workshop was organized in four sessions: Sessions 1 Sonic Boom Propagation (Theoretical); Session 2 Sonic Boom Propagation (Experimental); Session 3 Acceptability Studies-Human and Animal; and Session 4 - Configuration Design, Analysis, and Testing.

Influence of Chair Vibrations on Indoor Sonic Boom Annoyance

Science.gov (United States)

Rathsam, Jonathan; Klos, Jacob; Loubeau, Alexandra

2015-01-01

One goal of NASA’s Commercial Supersonic Technology Project is to identify candidate noise metrics suitable for regulating quiet sonic boom aircraft. A suitable metric must consider the short duration and pronounced low frequency content of sonic booms. For indoor listeners, rattle and creaking sounds and floor and chair vibrations may also be important. The current study examined the effect of such vibrations on the annoyance of test subjects seated indoors. The study involved two chairs exposed to nearly identical acoustic levels: one placed directly on the floor, and the other isolated from floor vibrations by pneumatic elastomeric mounts. All subjects experienced both chairs, sitting in one chair for the first half of the experiment and the other chair for the remaining half. Each half of the experiment consisted of 80 impulsive noises played at the exterior of the sonic boom simulator. When all annoyance ratings were analyzed together there appeared to be no difference in mean annoyance with isolation condition. When the apparent effect of transfer bias was removed, a subtle but measurable effect of vibration on annoyance was identified.

76 FR 20532 - Safety Zone; Boom Days, Niagara River, Niagara Falls, NY

Science.gov (United States)

2011-04-13

...-AA00 Safety Zone; Boom Days, Niagara River, Niagara Falls, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the Niagara River... Marina and a portion of the Niagara River, Niagara Falls, NY during the Boom Days Fireworks on April 16...

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.

Simulation and controller design for an agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the operation process. Thus we can guarantee the quality of the chemical droplets distribution on the crops. In this paper we introduced a sprayer boom leveling system for agricultural sprayer vehicles with electro-hydraulic auto-leveling system. The suitable hydraulic actuating cylinder and valve were selected according to the specific systemic specifications. Furthermore, a compensation controller for the electro-hydraulic system was designed based on the mathematical model. With simulations we can optimize the performance of this controller to make sure a fast leveling response to the inclined sprayer boom. © 2011 IEEE.

Babies Bottom Out--A 'Maybe Boom'

Science.gov (United States)

Science News, 1977

1977-01-01

Data for the period September 1976 through April 1977 indicate a rise in the United States birth rate; however, the rate is still below the replacement level. It is speculated that the increase is an "echo" effect to the post-World War II baby boom which peaked in 1957. (SL)

Impact of the electron donor on in situ microbial nitrate reduction in Opalinus Clay: results from the Mont Terri rock laboratory (Switzerland)

Energy Technology Data Exchange (ETDEWEB)

Bleyen, N.; Smets, S. [Belgian Nuclear Research Centre SCK-CEN, Mol (Belgium); Small, J. [National Nuclear Laboratory NLL, Warrington (United Kingdom); and others

2017-04-15

At the Mont Terri rock laboratory (Switzerland), an in situ experiment is being carried out to examine the fate of nitrate leaching from nitrate-containing bituminized radioactive waste, in a clay host rock for geological disposal. Such a release of nitrate may cause a geochemical perturbation of the clay, possibly affecting some of the favorable characteristics of the host rock. In this in situ experiment, combined transport and reactivity of nitrate is studied inside anoxic and water-saturated chambers in a borehole in the Opalinus Clay. Continuous circulation of the solution from the borehole to the surface equipment allows a regular sampling and online monitoring of its chemical composition. In this paper, in situ microbial nitrate reduction in the Opalinus Clay is discussed, in the presence or absence of additional electron donors relevant for the disposal concept and likely to be released from nitrate-containing bituminized radioactive waste: acetate (simulating bitumen degradation products) and H{sub 2} (originating from radiolysis and corrosion in the repository). The results of these tests indicate that - in case microorganisms would be active in the repository or the surrounding clay - microbial nitrate reduction can occur using electron donors naturally present in the clay (e.g. pyrite, dissolved organic matter). Nevertheless, non-reactive transport of nitrate in the clay is expected to be the main process. In contrast, when easily oxidizable electron donors would be available (e.g. acetate and H{sub 2}), the microbial activity will be strongly stimulated. Both in the presence of H{sub 2} and acetate, nitrite and nitrogenous gases are predominantly produced, although some ammonium can also be formed when H{sub 2} is present. The reduction of nitrate in the clay could have an impact on the redox conditions in the pore-water and might also lead to a gas-related perturbation of the host rock, depending on the electron donor used during denitrification

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

Science.gov (United States)

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

2013-03-01

Clays are materials commonly used in the pharmaceutical industry, either as ingredients or as active ingredients. It was observed that when they are administered concurrently, they may interact with drugs reducing their absorption. Therefore, such interactions can be used to achieve technological and biopharmaceutical advantages, regarding the control of release. This review summarizes bibliographic (articles) and technological (patents) information on the use of systems containing clays and clay minerals in modified drug delivery. In this area, formulations such natural clay, commercial clay, synthetic clay, composites clay-polymers, nanocomposites clay-polymers, films and hidrogels composites clay-polymers are used to slow/extend or vectorize the release of drugs and consequently they increase their bioavailability. Finally, this review summarizes the fields of technology and biopharmaceutical applications, where clays are applied. Copyright © 2012 Elsevier B.V. All rights reserved.

A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

Science.gov (United States)

Cliatt, Larry J., II; Haering, Edward A., Jr.; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

2014-01-01

In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center and the NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response (WSPR). Such tests will be applied to building a dataset that governing agencies such as the Federal Aviation Administration and the International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. The WSPR test was the first such effort that studied responses to non-traditional low sonic booms while the subject persons were in their own homes and performing daily activities.The WSPR test was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle (El Segundo, California). Other partners included Gulfstream Aerospace Corporation (Savannah, Georgia); Pennsylvania State University (University Park, Pennsylvania); Tetra Tech, Inc. (Pasadena, California); and Fidell Associates, Inc. (Woodland Hills, California).A major objective of the effort included exposing a community to the sonic boom magnitudes and occurrences that would be expected to occur in high-air traffic regions having a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data were collected using multiple

In situ geochemical properties of clays subject to thermal loading

International Nuclear Information System (INIS)

Chapman, N.A.

1980-01-01

Compositional variation and geochemical environment in an argillaceous unit are a function of age, depth of burial and mode of origin. This paper considers the variation limits likely to be encountered in potential repository host rocks and examines the significance of factors such as porosity, pore-fluid pressure, total fluid content, and major and accessory mineral component behaviors in controlling the geochemical environment in the neighbourhood of a thermally active waste canister. Particular attention is paid to the use of Eh-pH diagrams in assessing corrosion environments and nuclide speciation. The paper outlines the variables which must be considered when endeavouring to interpret such plots (e.g. temperature, concentration, concurrent reactions and probabilities) and uses the behavior of various iron minerals found in clay deposits under specific conditions to illustrate the complexities. The overall thermal stability of various clay and accessory minerals is discussed and extended to attempt to predict behavior under deep repository conditions, using available data on the diagenetic characteristics of clay-rich sediments. The physical behavior of fluids in plastic clays is considered and methods evaluated for deriving induced geochemical conditions in a thermally active repository. The latter section is particularly related to canister corrosion studies, in situ experiments, and waste dissolution parameters

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

International Nuclear Information System (INIS)

Mohajerani, M.

2011-01-01

During the different phases of the exothermic radioactive waste deep disposal (excavation, operation) and after permanent closure, the host rock is submitted to various coupled mechanical, hydraulic and thermal phenomena. Hence, a thorough investigation of the thermo-hydro-mechanical behaviour of the rock is necessary to complete existing data and to better understand and model the short and long term behaviour of the Callovo-Oxfordian (COx) clay formation in Bure (Meuse/Haute-Marne - M/HM), considered by ANDRA as a potential host rock in France.In this work, the compression - swelling behaviour of the COx Clay-stone was first investigated by carrying out a series of high-pressure oedometric tests. The results, interpreted in terms of coupling between damage and swelling, showed that the magnitude of swelling was linked to the density of the fissures created during compression. In a second step, the hydro-mechanical and thermo-hydro-mechanical behaviour of the saturated Clay-stone under a mean stress close to the in situ one were investigated by using two devices with short drainage path (10 mm), namely a isotropic cell and a newly designed hollow cylinder triaxial cell with local displacement measurements. These devices helped to solve two majors problems related to testing very low permeability materials: i) a satisfactory previous sample saturation (indicated by good Skempton values) and ii) satisfactory drainage conditions. Some typical constitutive parameters (Skempton and Biot's coefficients, drained and undrained compressibility coefficients) have been determined at ambient temperature through isotropic compression tests that also confirmed the transverse isotropy of the Clay-stone. The consistency of the obtained parameters has been checked in a saturated poro-elastic framework. Two aspects of the thermo-hydro-mechanical behaviour of the COx Clay-stone have then been investigated through different heating tests and through drained and undrained isotropic

Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

Energy Technology Data Exchange (ETDEWEB)

Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Mercante, Luiza A. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação, São Carlos, SP 13560 970 (Brazil); Soriano, Stéphane [Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24.210 346 (Brazil); Andruh, Marius [Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie nr. 23, Bucharest (Romania); Vieira, Méri D., E-mail: gqimeri@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Vaz, Maria G.F., E-mail: mariavaz@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil)

2015-08-15

In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar space of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.

A poor sealing Scenario for Deep disposal of high level waste

International Nuclear Information System (INIS)

Weetjens, E.

2005-01-01

Especially for geological disposal options in clay, the safety of the repository relies chiefly on the performance of the host formation as the main barrier. Understandably, scenarios in which this clay barrier is somehow bypassed earn great concern in PA (Performance Assessment) studies. The Poor Sealing Scenario is one of those scenarios that have been recently studied by the PA section of the Waste and Disposal department in the framework of the Belgian programme on deep disposal of high-level radwaste in Boom Clay. This scenario hypothesises that at least one disposal gallery and an access shaft have been poorly sealed off, providing a preferential pathway for RNs (radionuclides). The scenario further assumes a severe climate change, which would invert the presently downward hydraulic gradient, such that the potential impact would be maximal. The main objective is assessing the contribution from two transport processes to the overall radionuclide migration from a spent fuel repository towards the Neogene aquifer. The processes considered are advective transport through the poorly sealed repository and diffusive transport through the host formation. In addition, we would like to identify the most influential parameters with respect to repository design and performance

Influence of organic matter on the solubility of ThO2 and geochemical modeling

International Nuclear Information System (INIS)

Liu Dejun; Luo Tian; Maes, N.; Bruggeman, C.

2014-01-01

Thorium (IV) is widely considered in laboratory experiments as a suitable chemical analogue for long-lived tetravalent actinides. Th (IV) is redox-insensitive, as an analogue for U (IV) to study the influence of natural organic matter on the solubility. The solubility of crystalline ThO 2 (cr) has been measured under geochemical conditions representative for the Boom Clay using Real Boom Clay Water containing organic matter to assess its influence on the ThO 2 (cr) solubility. For the purpose of comparison, Aldrich Humic Acid was also investigated. Solubility measurements of ThO 2 (cr) were approached from under-saturation in an anaerobic glove box with a controlled Ar0.4%CO 2 atmosphere. Th concentration is determined after 30000 MWCO, 300000 MWCO, and 0.45 μm filtration to distinguish solid (0.45 μm), larger colloids (300000 MWCO), and small dissolved species(30000 MWCO). X-ray diffraction was carried out to investigate the transformation of ThO 2 (cr) phase during the contact with Boom Clay Water. In Synthetic Boom Clay Water (without organic matter) the concentrations of Th (IV) are 5 × l0 -ll mol/L, 4 × lO -10 mol/L, and 8 × lO -8 mol/L after 30000 MWCO, 300000 MWCO, and 0. 45 μm filtration, respectively. It indicated the existence of inorganic colloids in solution. The increase of the total Th solution concentration with increasing organic matter concentration revealed a complexation-like interaction between Th and organic matter. All the experimental data could be modeled by Tipping humic ion-binding model VI using a combination of solubility calculations and complexation reactions between Th (IV) and organic matter functional groups. Similar to the investigation of Eu 3+ solubility, the affinity of organic matter for Th was higher for Aldrich humic acid compared to Boom Clay organic matter. However, Boom Clay organic matter with different size had the similar complexation affinity with Th (IV). (authors)

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

International Nuclear Information System (INIS)

Marivoet, J.; Bonne, A.

1988-01-01

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

Luminescent Oxygen Gas Sensors Based on Nanometer-Thick Hybrid Films of Iridium Complexes and Clay Minerals

Directory of Open Access Journals (Sweden)

Hisako Sato

2014-01-01

Full Text Available The use of Ir(III complexes in photo-responsive molecular devices for oxygen gas sensing is reviewed. Attention is focused on the immobilization of Ir(III complexes in organic or inorganic host materials such as polymers, silica and clays in order to enhance robustness and reliability. Our recent works on constructing nanometer-thick films comprised of cyclometalated cationic Ir(III complexes and clay minerals are described. The achievement of multi-emitting properties in response to oxygen pressure is demonstrated.

In situ determination of anisotropic permeability of clay

International Nuclear Information System (INIS)

Shao, H.; Soennke, J.; Morel, J.; Krug, S.

2011-01-01

Argillaceous formations are being considered as potential host rocks for repositories of radioactive waste in many countries. For this purpose, the thermal, hydraulic, mechanical, and chemical properties of the clay stone are being widely investigated in the laboratories and in situ. However, clay stone behaves, due to its tectonic evolution of the formation, hydraulically and mechanically transversal isotropic. Argillite bedding or layering structure has been observed in the underground laboratories Mont Terri in the Switzerland and Meuse/Haute-Marne at Bure site in France. Conventional packer systems used for the borehole hydraulic characterisation cannot distinguish the difference between the properties parallel and perpendicular to the bedding. For this purpose, a new 'slot packer' system has been developed by the BGR. This type of new packer system is intensively tested in the BGR laboratory and the Mont Terri Rock Laboratory to judge the feasibility. The anisotropic ratio of the Opalinus clay defined by permeability value parallel to the bedding/permeability value perpendicular to the bedding is evaluated up to eight times to one order of magnitude within the HG-B experiment in the Mont Terri Rock Laboratory. Within the cooperation between BGR and ANDRA, the 'slot packer' will be used for the measurement of anisotropic permeability of the Callovo-Oxfordian formation at the Bure site. (authors)

Coupled Transport Phenomena in the Opalinus Clay: Implications for Radionuclide Transport

International Nuclear Information System (INIS)

Soler, J.M.

1999-09-01

Coupled phenomena (thermal and chemical osmosis, hyperfiltration, coupled diffusion, thermal diffusion, thermal filtration, Dufour effect) may play an important role in fluid, solute and heat transport in clay-rich formations, such as the Opalinus Clay (OPA), which are being considered as potential hosts for radioactive waste repositories. In this study, the potential effects of coupled phenomena on radionuclide transport in the vicinity of a repository for vitrified high-level radioactive waste (HLW) and spent nuclear fuel (SF) hosted by the Opalinus Clay, at times equal to or greater than the expected lifetime of the waste canisters (about 1000 years), have been addressed. Firstly, estimates of the solute fluxes associated with chemical osmosis, hyperfiltration, thermal diffusion and thermal osmosis have been calculated. Available experimental data concerning coupled transport phenomena in compacted clays, and the hydrogeological and geochemical conditions to which the Opalinus Clay is subject, have been used for these estimates. These estimates suggest that thermal osmosis is the only coupled transport mechanism that could have a strong impact on solute and fluid transport in the vicinity of the repository. Secondly, estimates of the heat fluxes associated with thermal filtration and the Dufour effect in the vicinity of the repository have been calculated. The calculated heat fluxes are absolutely negligible compared to the heat flux caused by thermal conduction. As a further step to obtain additional insight into the effects of coupled phenomena on solute transport, the solute fluxes associated with advection, chemical diffusion, thermal and chemical osmosis, hyperfiltration and thermal diffusion have been incorporated into a simple one-dimensional transport equation. The analytical solution of this equation, with appropriate parameters, shows again that thermal osmosis is the only coupled transport mechanism that could have a strong effect on repository

Coupled Transport Phenomena in the Opalinus Clay: Implications for Radionuclide Transport

Energy Technology Data Exchange (ETDEWEB)

Soler, J.M.

1999-09-01

Coupled phenomena (thermal and chemical osmosis, hyperfiltration, coupled diffusion, thermal diffusion, thermal filtration, Dufour effect) may play an important role in fluid, solute and heat transport in clay-rich formations, such as the Opalinus Clay (OPA), which are being considered as potential hosts for radioactive waste repositories. In this study, the potential effects of coupled phenomena on radionuclide transport in the vicinity of a repository for vitrified high-level radioactive waste (HLW) and spent nuclear fuel (SF) hosted by the Opalinus Clay, at times equal to or greater than the expected lifetime of the waste canisters (about 1000 years), have been addressed. Firstly, estimates of the solute fluxes associated with chemical osmosis, hyperfiltration, thermal diffusion and thermal osmosis have been calculated. Available experimental data concerning coupled transport phenomena in compacted clays, and the hydrogeological and geochemical conditions to which the Opalinus Clay is subject, have been used for these estimates. These estimates suggest that thermal osmosis is the only coupled transport mechanism that could have a strong impact on solute and fluid transport in the vicinity of the repository. Secondly, estimates of the heat fluxes associated with thermal filtration and the Dufour effect in the vicinity of the repository have been calculated. The calculated heat fluxes are absolutely negligible compared to the heat flux caused by thermal conduction. As a further step to obtain additional insight into the effects of coupled phenomena on solute transport, the solute fluxes associated with advection, chemical diffusion, thermal and chemical osmosis, hyperfiltration and thermal diffusion have been incorporated into a simple one-dimensional transport equation. The analytical solution of this equation, with appropriate parameters, shows again that thermal osmosis is the only coupled transport mechanism that could have a strong effect on repository

Spill-Overs of a Resource Boom: Evidence from Zambian Copper Mines

OpenAIRE

Alexander Lippert

2014-01-01

Do local populations benefit from resource booms? How strong are market linkages between the mining sector and the regional economy? This paper exploits exogenous variation in mine-level production volumes generated by the recent copper boom in Zambia to shed light on these questions. Using a novel dataset, I find robust evidence that an increase in local copper production improves living standards in the surroundings of the mines even for households not directy employed in the mining sector:...

Excavation Induced Hydraulic Response of Opalinus Clay - Investigations of the FE-Experiment at the Mont Terri URL in Switzerland

Science.gov (United States)

Vogt, T.; Müller, H. R.; Garitte, B.; Sakaki, T.; Vietor, T.

2013-12-01

The Full-Scale Emplacement (FE) Experiment at the Mont Terri underground research laboratory in Switzerland is a full-scale heater test in a clay-rich formation (Opalinus Clay). Based on the Swiss disposal concept it simulates the construction, emplacement, backfilling, and post-closure thermo-hydro-mechanical (THM) evolution of a spent fuel / vitrified high-level waste (SF / HLW) repository tunnel in a realistic manner. The main aim of this experiment is to investigate SF / HLW repository-induced THM coupled effects mainly in the host rock but also in the engineered barrier system (EBS), which consists of bentonite pellets and blocks. A further aim is to gather experience with full-scale tunnel construction and associated hydro-mechanical (HM) processes in the host rock. The entire experiment implementation (in a 50 m long gallery with approx. 3 m diameter) as well as the post-closure THM evolution will be monitored using a network of several hundred sensors (state-of-the-art sensors and measurement systems as well as fiber-optic sensors). The sensors are distributed in the host rock's near- and far-field, the tunnel lining, the EBS, and on the heaters. The heater emplacement and backfilling has not started yet, therefore only the host rock instrumentation is installed at the moment and is currently generating data. We will present the instrumentation concept and rationale as well as the first monitoring results of the excavation and ventilation phase. In particular, we investigated the excavation induced hydraulic response of the host rock. Therefore, the spatiotemporal evolution of porewater-pressure time series was analyzed to get a better understanding of HM coupled processes during and after the excavation phase as well as the impact of anisotropic geomechanic and hydraulic properties of the clay-rich formation on its hydraulic behavior. Excavation related investigations were completed by means of inclinometer data to characterize the non-elastic and time

Consequences of the Thermal Transient on the Evolution of the Damaged Zone Around a Repository for Heat-Emitting High-Level Radioactive Waste in a Clay Formation: a Performance Assessment Perspective

Science.gov (United States)

Yu, Li; Weetjens, Eef; Sillen, Xavier; Vietor, Tim; Li, Xiangling; Delage, Pierre; Labiouse, Vincent; Charlier, Robert

2014-01-01

A proper evaluation of the perturbations of the host rock induced by the excavation and the emplacement of exothermic wastes is essential for the assessment of the long-term safety of high-level radioactive waste disposals in clay formations. The impact of the thermal transient on the evolution of the damaged zone (DZ) has been explored in the European Commission project TIMODAZ (thermal impact on the damaged zone around a radioactive waste disposal in clay host rocks, 2006-2010). This paper integrates the scientific results of the TIMODAZ project from a performance assessment (PA) point of view, showing how these results support and justify key PA assumptions and the values of PA model parameters. This paper also contextualises the significance of the thermal impact on the DZ from a safety case perspective, highlighting how the project outcomes result into an improved understanding of the thermo-hydro-mechanical behaviour of the clay host rocks. The results obtained in the TIMODAZ project strengthen the assessment basis of the safety evaluation of the current repository designs. There was no evidence throughout the TIMODAZ experimental observations of a temperature-induced additional opening of fractures nor of a significant permeability increase of the DZ. Instead, thermally induced plasticity, swelling and creep seem to be beneficial to the sealing of fractures and to the recovery of a very low permeability in the DZ, close to that of an undisturbed clay host rock. Results from the TIMODAZ project indicate that the favourable properties of the clay host rock, which guarantee the effectiveness of the safety functions of the repository system, are expected to be maintained after the heating-cooling cycle. Hence, the basic assumptions usually made in PA calculations so far are expected to remain valid, and the performance of the system should not be affected in a negative way by the thermal evolution of the DZ around a radioactive waste repository in clay host rock.

Understanding the acquisition and regulation mechanisms of the water chemistry in a clay formation: the CEC/ANDRA Archimede-argile project

International Nuclear Information System (INIS)

Merceron, T.; Mossmann, J.R.; Neerdael, B.; Canniere, P. de; Beaucaire, C.; Toulhoat, P.; Daumas, S.; Bianchi, A.; Christen, R.

1993-01-01

Clay formations are candidate host environments to high level radioactive waste repository. The radioelements could be partially released from the waste into the host geological formation after a very long time. Understanding behaviour of the natural chemical species is considered as a fundamental prerequisite before the disturbed system will be studied. Additional laboratory studies are also essential in order to forecast, by analogy, the behaviour of radioelements released from the radioactive waste repository. The ARCHIMEDE-ARGILE project has two main goals. The first is to gain an understanding of the mechanisms of acquisition and regulation of the water chemistry in a clay environment. This step is essential to predict both the behaviour and the migration in solution of artificial elements which are initially absent in the clay formation. The second is to test and validate in clay the measured physico chemical parameters which are the basis for the geochemical modelling of the behaviour of the natural and artificial radioelements. The paper presents the main results previously obtained on granitic waters and the research strategy established for the ARCHIMEDE project. (authors). 2 figs., 2 refs

Retention of contaminants Cd and Hg adsorbed and intercalated in aluminosilicate clays: A first principles study

Science.gov (United States)

Crasto de Lima, F. D.; Miwa, R. H.; Miranda, Caetano R.

2017-11-01

Layered clay materials have been used to incorporate transition metal (TM) contaminants. Based on first-principles calculations, we have examined the energetic stability and the electronic properties due to the incorporation of Cd and Hg in layered clay materials, kaolinite (KAO) and pyrophyllite (PYR). The TM can be (i) adsorbed on the clay surface as well as (ii) intercalated between the clay layers. For the intercalated case, the contaminant incorporation rate can be optimized by controlling the interlayer spacing of the clay, namely, pillared clays. Our total energy results reveal that the incorporation of the TMs can be maximized through a suitable tuning of vertical distance between the clay layers. Based on the calculated TM/clay binding energies and the Langmuir absorption model, we estimate the concentrations of the TMs. Further kinetic properties have been examined by calculating the activation energies, where we found energy barriers of ˜20 and ˜130 meV for adsorbed and intercalated cases, respectively. The adsorption and intercalation of ionized TM adatoms were also considered within the deprotonated KAO surface. This also leads to an optimal interlayer distance which maximizes the TM incorporation rate. By mapping the total charge transfers at the TM/clay interface, we identify a net electronic charge transfer from the TM adatoms to the topmost clay surface layer. The effect of such a charge transfer on the electronic structure of the clay (host) has been examined through a set of X-ray absorption near edge structure (XANES) simulations, characterizing the changes of the XANES spectra upon the presence of the contaminants. Finally, for the pillared clays, we quantify the Cd and Hg K-edge energy shifts of the TMs as a function of the interlayer distance between the clay layers and the Al K-edge spectra for the pristine and pillared clays.

Vibration characteristics of a deployable controllable-geometry truss boom

Science.gov (United States)

Dorsey, J. T.

1983-01-01

An analytical study was made to evaluate changes in the fundamental frequency of a two dimensional cantilevered truss boom at various stages of deployment. The truss could be axially deployed or retracted and undergo a variety of controlled geometry changes by shortening or lengthening the telescoping diagonal members in each bay. Both untapered and tapered versions of the truss boom were modeled and analyzed by using the finite element method. Large reductions in fundamental frequency occurred for both the untapered and tapered trusses when they were uniformly retracted or maneuvered laterally from their fully deployed position. These frequency reductions can be minimized, however, if truss geometries are selected which maintain cantilever root stiffness during truss maneuvers.

Use of swelling clays to reduce permeability and its potential application to nuclear waste repository sealing

International Nuclear Information System (INIS)

Moore, D.E.; Morrow, C.A.; Byerlee, J.D.

1982-01-01

The injection of swelling-clay slurries into joints or faults at a deep-burial nuclear waste disposal site may result in signficant permeability reductions for the effective containment of radioactive wastes. In an experiment conducted to illustrate the permeability change accompanying clay swelling, a coarse stone with interconnected pore spaces was injected with a clay-electrolyte slurry, modelling the pressure-grouting of a fractured repository rock. Subsequently, solutions with lower electroylte concentrations were driven through the clay-filled stone, corresponding to migration of lower salinity ground-waters through the clay-grouted fracture. The initial injection procedure reduced the permeability of the stone from 1--10 darcies to 700 nanodarcies; the changes in solution composition decreased permeability by more than 2 additional orders of magnitude to 3 nanodarcies. For application at a nuclear waste repository, the electrolyte concentration of the injected clay slurry should be made higher than that of the ground-water in the host rock. Subesquent interaction of the ground-water with the clays would initiate swelling and create the additional, post-injection permeability reductions that may be important in preventing the escape of buried radioactive wastes. The measured permeability of the clay filling is considerably lower than that of cement tested for borehole plugging. Clays also have the advantage over cement and chemical grouts in that they are geologically stable at relatively low temperatures and have a high capacity for radionuclide adsorption

Report on Modeling Coupled Processes in the Near Field of a Clay Repository

Energy Technology Data Exchange (ETDEWEB)

Liu, Hui -Hai [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, Jim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Li, Lianchong [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Asahina, Daisuke [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Fei [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Birkholzer, Jens [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-08-01

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world. Coupled thermal, hydrological, mechanical, and chemical (THMC) processes have a significant impact on the long-term safety of a clay repository. For example, the excavation damaged zone (EDZ) near repository tunnels can modify local permeability (resulting from induced fractures), potentially leading to less confinement capability. This report documents results from three R&D activities: (1) implementation and validation of constitutive relationships, (2) development of a discrete fracture network (DFN) model for investigating coupled processes in the EDZ, and (3) development of a THM model for the FE tests at Mont Terri, Switzerland, for the purpose of model validation. The overall objective of these activities is to provide an improved understanding of EDZ evolution in clay repositories and the associated coupled processes, and to develop advanced relevant modeling capabilities.

Elastic Deployable Composite Tubular Roll-Out Boom, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Deployable Space Systems (DSS) has developed an affordable and ultra-lightweight elastically self-deployable Roll-Out Boom technology that provides affordability and...

Comprehensive review of geosynthetic clay liner and compacted clay liner

Science.gov (United States)

Shankar, M. Uma; Muthukumar, M.

2017-11-01

Human activity inevitably produces waste materials that must be managed. Some waste can be reused. However many wastes that cannot be used beneficially must be disposed of ensuring environmental safety. One of the common methods of disposal is landfilling. The most common problems of the landfill site are environmental degradation and groundwater contamination caused by leachate produced during the decomposition process of organic material and rainfall. Liner in a landfill is an important component which prevent leachate migration and prevent groundwater contamination. Earthen liners have been widely used to contain waste materials in landfill. Liners and covers for municipal and hazardous waste containment facilities are often constructed with the use of fine-grained, low plasticity soils. Because of low permeability geosynthetic clay liners and compacted clay liners are the main materials used in waste disposal landfills. This paper summaries the important geotechnical characteristics such as hydraulic conductivity, liquid limit and free swell index of geosynthetic clay liner and compacted clay liner based on research findings. This paper also compares geosynthetic clay liner and compacted clay liner based on certain criteria such as thickness, availability of materials, vulnerability to damage etc.

The marriage boom and marriage bust in the United States: An age-period-cohort analysis.

Science.gov (United States)

Schellekens, Jona

2017-03-01

In the 1950s and 1960s there was an unprecedented marriage boom in the United States. This was followed in the 1970s by a marriage bust. Some argue that both phenomena are cohort effects, while others argue that they are period effects. The study reported here tested the major period and cohort theories of the marriage boom and bust, by estimating an age-period-cohort model of first marriage for the years 1925-79 using census microdata. The results of the analysis indicate that the marriage boom was mostly a period effect, although there were also cohort influences. More specifically, the hypothesis that the marriage boom was mostly a response to rising wages is shown to be consistent with the data. However, much of the marriage bust can be accounted for by unidentified cohort influences, at least until 1980.

Clay dispersibility and soil friability – testing the soil clay-to-carbon saturation concept

OpenAIRE

Schjønning, P.; de Jonge, L.W.; Munkholm, L.J.; Moldrup, P.; Christensen, B.T.; 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 ...

30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

Science.gov (United States)

2010-07-01

...-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any...

Ultra-thin clay layers facilitate seismic slip in carbonate faults.

Science.gov (United States)

Smeraglia, Luca; Billi, Andrea; Carminati, Eugenio; Cavallo, Andrea; Di Toro, Giulio; Spagnuolo, Elena; Zorzi, Federico

2017-04-06

Many earthquakes propagate up to the Earth's surface producing surface ruptures. Seismic slip propagation is facilitated by along-fault low dynamic frictional resistance, which is controlled by a number of physico-chemical lubrication mechanisms. In particular, rotary shear experiments conducted at seismic slip rates (1 ms -1 ) show that phyllosilicates can facilitate co-seismic slip along faults during earthquakes. This evidence is crucial for hazard assessment along oceanic subduction zones, where pelagic clays participate in seismic slip propagation. Conversely, the reason why, in continental domains, co-seismic slip along faults can propagate up to the Earth's surface is still poorly understood. We document the occurrence of micrometer-thick phyllosilicate-bearing layers along a carbonate-hosted seismogenic extensional fault in the central Apennines, Italy. Using friction experiments, we demonstrate that, at seismic slip rates (1 ms -1 ), similar calcite gouges with pre-existing phyllosilicate-bearing (clay content ≤3 wt.%) micro-layers weaken faster than calcite gouges or mixed calcite-phyllosilicate gouges. We thus propose that, within calcite gouge, ultra-low clay content (≤3 wt.%) localized along micrometer-thick layers can facilitate seismic slip propagation during earthquakes in continental domains, possibly enhancing surface displacement.

An evaluation of propane as a fuel for testing fire-resistant oil spill containment booms

International Nuclear Information System (INIS)

Walton, W. D.; Twilley, W. H.

1997-01-01

A series of experiments have been conducted to measure and compare the thermal exposure to a fire-resistant boom from liquid hydrocarbon fuel and propane fires. The objective was to test the potential of propane fueled fires as a fire source for testing fire-resistant oil spill containment booms.Thermal exposure from propane fires have been measured with and without waves. Results indicated that although propane diffusion flames on water look like liquid hydrocarbon fuel flames and produce very little smoke, the heat flux at the boom location from propane fires is about 60 per cent of that from liquid hydrocarbon fuel fires. Despite the attractive features in terms of ease of application, control and smoke emissions, it was concluded that the low heat flux would preclude the application of propane as a fuel for evaluating fire resistant containment booms. 2 refs., 7 figs

Economic Booms and Risky Sexual Behavior: Evidence from Zambian Copper Mining Cities

OpenAIRE

Nicholas Wilson

2010-01-01

Existing studies suggest that individual and household level economic shocks affect the demand for and supply of risky sex. However, little evidence exists on the effects of an aggregate shock on equilibrium risky sexual behavior. This paper examines the effects of the early twenty-first century copper boom on risky sexual behavior in Zambian copper mining cities. The results indicate that the copper boom substantially reduced rates of transactional sex and multiple partnerships in copper min...

Anisotropic modelling of Opalinus Clay behaviour: From triaxial tests to gallery excavation application

Directory of Open Access Journals (Sweden)

François Bertrand

2017-06-01

Full Text Available Deep repository in geological formations is the preferential solution considered in many countries to manage high-level nuclear wastes. In Switzerland, the Opalinus Clay is a candidate host rock. In this context, in situ and laboratory tests are conducted on Opalinus Clay to demonstrate the feasibility of deep disposal in this argillaceous formation. This paper presents a constitutive model able to fit the experimental data obtained from some triaxial tests conducted by Jahns (2013 on cores from borehole Schlattingen SLA-1. The elasto-plastic behaviour of Opalinus Clay is reproduced thanks to a Drucker-Prager model, taking into account the anisotropy behaviour of this sedimentary rock. The objective is to employ a single set of parameters representative of the material. In a second version of the model, the stress-dependence of the elastic properties and damage are taken into account. Finally, the parameters calibrated with experimental tests are used to simulate the excavation of a gallery with a second gradient approach.

Multiscale Micromechanical Modeling of Polymer/Clay Nanocomposites and the Effective Clay Particle

Science.gov (United States)

Sheng, Nuo; Boyce, Mary C.; Parks, David M.; Manovitch, Oleg; Rutledge, Gregory C.; Lee, Hojun; McKinley, Gareth H.

2003-03-01

Polymer/clay nanocomposites have been observed to exhibit enhanced mechanical properties at low weight fractions (Wp) of clay. Continuum-based composite modeling reveals that the enhanced properties are strongly dependent on particular features of the second-phase ¡°particles¡+/-; in particular, the particle volume fraction (fp), the particle aspect ratio (L/t), and the ratio of particle mechanical properties to those of the matrix. However, these important aspects of as-processed nanoclay composites have yet to be consistently and accurately defined. A multiscale modeling strategy was developed to account for the hierarchical morphology of the nanocomposite: at a lengthscale of thousands of microns, the structure is one of high aspect ratio particles within a matrix; at the lengthscale of microns, the clay particle structure is either (a) exfoliated clay sheets of nanometer level thickness or (b) stacks of parallel clay sheets separated from one another by interlayer galleries of nanometer level height. Here, quantitative structural parameters extracted from XRD patterns and TEM micrographs are used to determine geometric features of the as-processed clay ¡°particles¡+/-, including L/t and the ratio of fp to Wp. These geometric features, together with estimates of silicate lamina stiffness obtained from molecular dynamics simulations, provide a basis for modeling effective mechanical properties of the clay particle. The structure-based predictions of the macroscopic elastic modulus of the nanocomposite as a function of clay weight fraction are in excellent agreement with experimental data. The adopted methodology offers promise for study of related properties in polymer/clay nanocomposites.

Real estate boom and export performance bust in Croatia

Directory of Open Access Journals (Sweden)

Marina Tkalec

2014-06-01

Full Text Available The goal of this research is to estimate the effect of resource reallocation from the manufacturing to the real estate economic sector on exporting activity in Croatia, a small open post-transition country that experienced a real estate boom during the previous decade. This paper follows the work by Égert and Kierzenkowski (2014 as we test the hypothesis that the real estate boom had an adverse impact on country’s export performance. For that purpose we use quarterly data ranging from 1Q1998 to 3Q2013, and estimate export equations using maximum likelihood and dynamic ordinary least squares estimators of cointegration. Our results indicate that the distortion of relative prices in favor of non-tradable sectors (construction and real estate, which is a direct by-product of the real estate boom, has had stifling effects on export performance. Our results also suggest that ailing cost competitiveness and governments’ inability to implement policies promoting private sector economic development adversely influenced export performance during the period analyzed. The basic conclusion of our research is that the expansion of a non-tradable sector in a country with limited supply of production factors can have a detrimental effect on the ability of the tradable sector to increase its output and compete in international markets.

Bearings for the biomass boom

Energy Technology Data Exchange (ETDEWEB)

MacQueen, Duncan

2011-03-15

Biomass energy is booming –– more than two billion people depend on biomass for their energy and the International Energy Agency predicts that biomass' share of the global energy supply will treble by 2050. But in many developing countries it is still regarded as a traditional and dirty solution that is often criminalised, unsustainable and poorly paid. A more sophisticated approach that legalises and secures sustainable production by and for local people could help improve energy security, cut carbon emissions, protect forests and reduce poverty.

The research and application of electricity economic boom model under the constraint of energy conservation and emission reduction

Science.gov (United States)

Chen, Guangyan; Xia, Huaijian; Chen, Meiling; Wang, Dong; Jia, Sujin

2017-10-01

Energy saving and emission reduction policies affects the development of high power industry, thereby affecting electricity demand, so the study of the electricity industry boom helps to master the national economy. This paper analyses the influence of energy saving and emission reduction on power generation structure and pollutant emission in power industry. Through the construction of electricity market composite boom index to indicate electricity boom, using boom index to study volatility characteristics and trend of electricity market. Here we provide a method for the enterprise and the government, that it can infer the overall operation of the national economy situation from power data.

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

International Nuclear Information System (INIS)

Chaudhary, D.S.; Prasad, R.; Gupta, R.K.; Bhattacharya, S.N.

2005-01-01

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

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

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 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 effects on clay...

Rural North Dakota's oil boom and its impact on social services.

Science.gov (United States)

Weber, Bret A; Geigle, Julia; Barkdull, Carenlee

2014-01-01

Over the last five years, North Dakota has experienced an oil boom based on high oil prices and hydraulic fracturing technologies. This has brought economic expansion and population growth to rural communities that had previously experienced decades of depopulation and economic struggle. Although the state has enjoyed many benefits--especially in juxtaposition to a sluggish national economy--the boom has also meant the arrival of economic refugees and dramatic impacts on largely rural social service systems. In the midst of a rapidly changing situation, available information tends to swing between euphoria over economic success and hysteria about rising crime and shifting cultures. In response, the authors used a primary focus group with county social service directors from across the state and a followup focus group with social workers operating on the edge of oil activity. Grounded in resilience theory, qualitative analysis of the primary focus group, and triangulation of data from other sources, this study provides a more objective report of the housing and social challenges, the benefits of the boom, and the challenges to solutions.

Clay Mineralogy of AN Alluvial Aquifer in a Mountainous, Semiarid Terrain, AN Example from Rifle, Colorado

Science.gov (United States)

Elliott, W. C.; Lim, D.; Zaunbrecher, L. K.; Pickering, R. A.; Williams, K. H.; Navarre-Sitchler, A.; Long, P. E.; Noel, V.; Bargar, J.; Qafoku, N. P.

2015-12-01

Alluvial sediments deposited along the Colorado River corridor in the semi-arid regions of central to western Colorado can be important hosts for legacy contamination including U, V, As and Se. These alluvial sediments host aquifers which are thought to provide important "hot spots" and "hot moments" for microbiological activity controlling organic carbon processing and fluxes in the subsurface. Relatively little is known about the clay mineralogy of these alluvial aquifers and the parent alluvial sediments in spite of the fact that they commonly include lenses of silt-clay materials. These lenses are typically more reduced than coarser grained materials, but zones of reduced and more oxidized materials are present in these alluvial aquifer sediments. The clay mineralogy of the non-reduced parent alluvial sediments of the alluvial aquifer located in Rifle, CO (USA) is composed of chlorite, smectite, illite, kaolinite and quartz. The clay mineralogy of non-reduced fine-grained materials at Rifle are composed of the same suite of minerals found in the sediments plus a vermiculite-smectite intergrade that occurs near the bottom of the aquifer near the top of the Wasatch Formation. The clay mineral assemblages of the system reflect the mineralogically immature character of the source sediments. These assemblages are consistent with sediments and soils that formed in a moderately low rainfall climate and suggestive of minimal transport of the alluvial sediments from their source areas. Chlorite, smectite, smectite-vermiculite intergrade, and illite are the likely phases involved in the sorption of organic carbon and related microbial redox transformations of metals in these sediments. Both the occurrence and abundance of chlorite, smectite-vermiculite, illite and smectite can therefore exert an important control on the contaminant fluxes and are important determinants of biogeofacies in mountainous, semiarid terrains.

SBR Brazilian organophilic/clay nanocomposites

International Nuclear Information System (INIS)

Guimaraes, Thiago R.; Valenzuela-Diaz, Francisco R.; Morales, Ana Rita; Paiva, Lucilene B.

2009-01-01

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

Atrazine biodegradation modulated by clays and clay/humic acid complexes

International Nuclear Information System (INIS)

Besse-Hoggan, Pascale; Alekseeva, Tatiana; Sancelme, Martine; Delort, Anne-Marie; Forano, Claude

2009-01-01

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

Influence of Polymer-Clay Interfacial Interactions on the Ignition Time of Polymer/Clay Nanocomposites.

Science.gov (United States)

Zope, Indraneel S; Dasari, Aravind; Yu, Zhong-Zhen

2017-08-11

Metal ions present on smectite clay (montmorillonite) platelets have preferential reactivity towards peroxy/alkoxy groups during polyamide 6 (PA6) thermal decomposition. This changes the decomposition pathway and negatively affects the ignition response of PA6. To restrict these interfacial interactions, high-temperature-resistant polymers such as polyetherimide (PEI) and polyimide (PI) were used to coat clay layers. PEI was deposited on clay by solution-precipitation, whereas PI was deposited through a solution-imidization-precipitation technique before melt blending with PA6. The absence of polymer-clay interfacial interactions has resulted in a similar time-to-ignition of PA6/PEI-clay (133 s) and PA6/PI-clay (139 s) composites as neat PA6 (140 s). On the contrary, PA6 with conventional ammonium-based surfactant modified clay has showed a huge drop in time-to-ignition (81 s), as expected. The experimental evidences provided herein reveal the role of the catalytic activity of clay during the early stages of polymer decomposition.

Environmental Pollution: Noise Pollution - Sonic Boom. Volume I.

Science.gov (United States)

Defense Documentation Center, Alexandria, VA.

The unclassified, annotated bibliography is Volume I of a two-volume set on Noise Pollution - Sonic Boom in a series of scheduled bibliographies on Environmental Pollution. Volume II is Confidential. Corporate author-monitoring agency, subject, title, contract, and report number indexes are included. (Author/JR)

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-07-01

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

Nearfield behaviour of clay barriers and their interaction with concrete Task 3 characterization of radioactive waste forms a series of final reports (1985-89) No 26

International Nuclear Information System (INIS)

Atabek, R.; Beziat, A.; Coulon, H.; Dardaine, M.; Eglem, A.; Farcy, C.; Fontan, N.; Gatabin, C.; Gegout, P.; Lajudie, A.; Landoas, O.; Lechelle, J.; Plas, F.; Raynal, J.; Revertegat, E.; Debrabant, P.; Proust, D.

1991-01-01

In order to guarantee the safety of waste underground disposal, engineered barriers will be implemented as backfill materials in galleries and access shafts and as buffer materials between the host medium and the waste packages. One of the first requirements for engineered barriers is to minimize water and chemical species transfer. The materials being considered are essentially swelling clays, in particular calcium smectite clays coming from french deposits and hydraulic binders, more specially a ternary cement (named C.L.C.). A vitrified waste disposal in granite is taken as the most constraining scenario as far as engineered barrier is concerned. The clay buffer material is placed between the packages and the host rock. The main properties which are determined are directly related to the engineered barrier requirements: thermal conductivity, hydraulic conductivity, swelling pressure and swelling capacity. Moreover results are obtained on temperature effect on clay microstructure and properties in both cases: without and with water intake. The concrete durability with regard to clay pore water attack is evaluated taking into account previous results obtained to ensure low-level radioactive waste disposal safety. 23 refs., 29 figs., 10 tabs

Phosphonium modified clay/polyimide nanocomposites

International Nuclear Information System (INIS)

Ceylan, Hatice; Çakmakçi, Emrah; Beyler-Çiǧil, Asli; Kahraman, Memet Vezir

2014-01-01

In this study, octyltriphenylphosphonium bromide [OTPP-Br] was prepared from the reaction of triphenylphosphine and 1 -bromooctane. The modification of clay was done by ion exchange reaction using OTPP-Br in water medium. Poly(amic acid) was prepared from the reaction of 3,3',4,4'-Benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-Oxydianiline (ODA). Polyimide(PI)/clay hybrids were prepared by blending of poly(amic acid) and organically modified clay as a type of layered clays. The morphology of the Polyimide/ phosphonium modified clay hybrids was characterized by scanning electron microscopy (SEM). Chemical structures of polyimide and Polyimide/ phosphonium modified clay hybrids were characterized by FTIR. SEM and FTIR results showed that the Polyimide/ phosphonium modified clay hybrids were successfully prepared. Thermal properties of the Polyimide/ phosphonium modified clay hybrids were characterized by thermogravimetric analysis (TGA)

Boom in boarfish abundance: insight from otolith analysis

DEFF Research Database (Denmark)

Coad, Julie Olivia; Hüssy, Karin

2012-01-01

The boarfish Capros aper is a pelagic shoaling species widely distributed along the Northeast Atlantic continental shelf. In recent years, this species has experienced a dramatic boom in abundance in the Bay of Biscay and Celtic Sea. This study aims at resolving the mechanisms responsible for thi...

Investigations on THM effects in buffer, EDZ and argillaceous host rock. Final report

Energy Technology Data Exchange (ETDEWEB)

Jobmann, M.; Breustedt, M.; Li, S.; Polster, M.; Schirmer, S.

2013-11-15

In the Federal Republic of Germany the final disposal of heat-generating radioactive waste in clay formations is investigated as an alternative to the reference concept in a salt formation. The main concern when switching to a clay host rock is the high amount of heat released from the canisters into the clay rock over a long period of time. It is still an open question to what extent the host rock formation is affected by the released heat and if this is a threat to safety. The released heat from the canisters is a load on the whole barrier system, which consists of the geotechnical barriers (buffer and plugs) and the geological barrier. The temperature has a direct impact on the buffer, the excavative damaged zone (EDZ) and the surrounding host rock. The buffer has specific thermo-physical properties that significantly influence the temperature evolution in the near field so that a temperature load on the buffer is of special concern. Thus, with regard to thermal criteria, the buffer plays a significant role for the design of the emplacement fields. An open question is whether the use of admixtures could enhance the thermo-physical properties so that the heat release into the host rock would be more efficient. Due to the permanent heat release and the continuous emplacement of additional canisters, the in-situ stress state in the vicinity of the emplacement boreholes continuously varies during the operational period and beyond. It is an open question how the EDZ of emplacement boreholes evolves in the long term with regard to its fissure system and mainly its permeability. A closure of the EDZ and a corresponding decrease in its permeability are necessary to enhance the tightness of the barrier system, especially to avoid a preferential pathway through the EDZ around the openings. The host rock has specific properties that are necessary to ensure a safe enclosure of the waste. A change in the host rock temperature may change these properties irreversibly. This is

Long term effects on potential repository sites: the alteration of the Lower Oxford Clay during weathering

International Nuclear Information System (INIS)

Milowdowski, A.E.; Bloodworth, A.J.; Wilmot, R.D.

1985-09-01

The report is one of a short series describing work carried out to investigate the long-term effects of various geological processes on the performance of both shallow and deep repositories for low and intermediate-level radioactive wastes. This paper deals with the alteration as a result of weathering of the Lower Oxford Clay, a potential host rock for shallow disposal of wastes. A description of the Lower Oxford Clay is given, along with the weathering of argillaceous rocks. Investigations of the weathering at the Elstow Storage Depot are described, as well as the implications for radioactive waste disposal. (U.K.)

Selection of the host rock for high level radioactive waste repository in China

International Nuclear Information System (INIS)

Jin Yuanxin; Wang Wenguang; Chen Zhangru

2001-01-01

The authors has briefly introduced the experiences of the host rock selection and the host rock types in other countries for high level radioactive waste repository. The potential host rocks in China are investigated. They include granite, tuff, clay, basalt, salt, and loess. The report has expounded the distributions, scale, thickness, mineral and chemical composition, construction, petrogenesis and the ages of the rock. The possibility of these rocks as the host rock has been studied. The six pieces of distribution map of potential rocks have been made up. Through the synthetical study, it is considered that granite as the host rock of high level radioactive waste repository is possible

Common clay and shale

Science.gov (United States)

Virta, R.L.

2000-01-01

Part of the 1999 Industrial Minerals Review. The clay and shale market in 1999 is reviewed. In the U.S., sales or use of clay and shale increased from 26.4 million st in 1998 to 27.3 million st in 1999, with an estimated 1999 value of production of $143 million. These materials were used to produce structural clay products, lightweight aggregates, cement, and ceramics and refractories. Production statistics for clays and shales and for their uses in 1999 are presented.

Effects of modified Clay on the morphology and thermal stability of PMMA/clay nanocomposites

International Nuclear Information System (INIS)

Tsai, Tsung-Yen; Lin, Mei-Ju; Chuang, Yi-Chen; Chou, Po-Chiang

2013-01-01

The potential to improve the mechanical, thermal, and optical properties of poly(methyl methacrylate) (PMMA)/clay nanocomposites prepared with clay containing an organic modifier was investigated. Pristine sodium montmorillonite clay was modified using cocoamphodipropionate, which absorbs UVB in the 280–320 nm range, via ion exchange to enhance the compatibility between the clay platelets and the methyl methacrylate polymer matrix. PMMA/clay nanocomposites were synthesized via in situ free-radical polymerization. Three types of clay with various cation-exchange capacities (CEC) were used as inorganic layered materials in these organic–inorganic hybrid nanocomposites: CL42, CL120, and CL88 with CEC values of 116, 168, and 200 meq/100 g of clay, respectively. We characterized the effects of the organoclay dispersion on UV resistance, effectiveness as an O 2 gas barrier, thermal stability, and mechanical properties of PMMA/clay nanocomposites. Gas permeability analysis demonstrated the excellent gas barrier properties of the nanocomposites, consistent with the intercalated or exfoliated morphologies observed. The optical properties were assessed using UV–Visible spectroscopy, which revealed that these materials have good optical clarity, UV resistance, and scratch resistance. The effect of the dispersion capability of organoclay on the thermal properties of PMMA/clay nanocomposites was investigated by thermogravimetric analysis and differential scanning calorimetry; these analyses revealed excellent thermal stability of some of the modified clay nanocomposites. - Highlights: ► We control the dispersion morphology by protonation of K2 into the clay. ► The CL120 and CL88, with the higher CEC, are more random intercalated by K2. ► We report these materials have good optical clarity, and UV resistance

Selective Clay Placement Within a Silicate-Clay Epoxy Blend Nanocomposite

Science.gov (United States)

Miller, Sandi G (Inventor)

2013-01-01

A clay-epoxy nanocomposite may be prepared by dispersing a layered clay in an alkoxy epoxy, such as a polypropylene oxide based epoxide before combining the mixture with an aromatic epoxy to improve the nanocomposite's thermal and mechanical properties.

Clay nanoparticles for regenerative medicine and biomaterial design: A review of clay bioactivity.

Science.gov (United States)

Mousa, Mohamed; Evans, Nicholas D; Oreffo, Richard O C; Dawson, Jonathan I

2018-03-01

Clay nanoparticles, composites and hydrogels are emerging as a new class of biomaterial with exciting potential for tissue engineering and regenerative medicine applications. Clay particles have been extensively explored in polymeric nanocomposites for self-assembly and enhanced mechanical properties as well as for their potential as drug delivery modifiers. In recent years, a cluster of studies have explored cellular interactions with clay nanoparticles alone or in combination with polymeric matrices. These pioneering studies have suggested new and unforeseen utility for certain clays as bioactive additives able to enhance cellular functions including adhesion, proliferation and differentiation, most notably for osteogenesis. This review examines the recent literature describing the potential effects of clay-based nanomaterials on cell function and examines the potential role of key clay physicochemical properties in influencing such interactions and their exciting possibilities for regenerative medicine. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Boom in Boomerangs

Science.gov (United States)

1992-01-01

Ted Bailey, a highly-ranked international boomerang designer and thrower, used information from a variety of NASA technical reports on aerodynamics and low-speed airfoils to design more competitive boomerangs. Because the boomerang is essentially an airfoil like an airplane wing, the technology transferred effectively and even contributed to the 1981 American victory over Australian throwers. In 1985, using four NASA reports, Bailey designed a new MTA (maximum time aloft) boomerang that broke the one-minute barrier, enabled throwers to throw and catch in less than three minutes and allowed competitors to complete the difficult "Super Catch" - five throw/catch sequences after launching the original boom while it is still aloft. Bailey is now considering other boomerang applications.

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

International Nuclear Information System (INIS)

Vu-Do, Laurence

2013-01-01

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; PCO 2 =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)

Thixotropic Properties of Latvian Clays

OpenAIRE

Lakevičs, Vitālijs; Stepanova, Valentīna; Ruplis, Augusts

2015-01-01

This research studies Latvia originated Devon (Tūja, Skaņkalne), quaternary (Ceplīši), Jurassic, (Strēļi) and Triassic (Vadakste) deposit clays as well as Lithuania originated Triassic (Akmene) deposit clays. Thixotropic properties of clay were researched by measuring relative viscosity of clay in water suspensions. Relative viscosity is measured with a hopper method. It was detected that, when concentration of suspension is increased, clay suspension’s viscosity also increases. It happens un...

Experimental study of mechanical behaviour of a clay-stone: application to nuclear waste disposals

International Nuclear Information System (INIS)

Chiarelli, A.S.; Shao, J.F.; Ledesert, B.; Hoteit, N.

2001-01-01

A study of mechanical behaviour of deep argillaceous rocks from East of France, the 'argilites de l'Est' as a potential host rock for radioactive waste disposal studied by ANDRA, (french national radioactive waste management agency) is presented. Some uniaxial and triaxial compression tests with unloading-reloading cycles were realised on samples from three different depths. Important plastic strains associated to directional degradation of elastic properties show that the two principles strain mechanisms are plasticity and induced anisotropic damage. At microscopic scale, it is related to sliding of clay sheets and oriented microcracks. The influence of mineralogy is that brittle behaviour is more important with calcite while it decreases with clay. (authors)

Analysis of Offshore Knuckle Boom Crane - Part Two: Motion Control

Directory of Open Access Journals (Sweden)

Morten K. Bak

2013-10-01

Full Text Available In this paper design of electro-hydraulic motion control systems for offshore knuckle boom cranes is discussed. The influence of the control valve bandwidth along with the ramp time for the control signal are investigated both analytically with simplified system models and numerically with an experimentally verified crane model. The results of both types of investigations are related to general design rules for selection of control valves and ramp times and the relevance of these design rules is discussed. Generally, they are useful but may be too conservative for offshore knuckle boom cranes. However, as demonstrated in the paper, the only proper way to determine this is to evaluate the motion control system design by means of simulation.

Clay minerals behaviour in thin sandy clay-rich lacustrine turbidites (Lake Hazar, Turkey)

Science.gov (United States)

El Ouahabi, Meriam; Hubert-Ferrari, Aurelia; Lamair, Laura; Hage, Sophie

2017-04-01

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing relationships between the flow characteristics and their deposits. In particular, flume experiments emphasize that the presence of clay plays a key role in turbidity current dynamics. Clay fraction, in small amount, provides cohesive strength to sediment mixtures and can damp turbulence. However, the degree of flocculation is dependent on factors such as the amount and size of clay particles, the surface of clay particles, chemistry and pH conditions in which the clay particles are dispersed. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in stacked thin beds. Depositional processes and sources have been previously studied and three types were deciphered, including laminar flows dominated by cohesion, transitional, and turbulence flow regimes (Hage et al., in revision). For the purpose of determine the clay behavior in the three flow regimes, clay mineralogical, geochemical measurements on the cores allow characterising the turbidites. SEM observations provide further information regarding the morphology of clay minerals and other clasts. The study is particularly relevant given the highly alkaline and saline water of the Hazar Lake. Clay minerals in Hazar Lake sediments include kaolinite (1:1-type), illite and chlorite (2:1-type). Hazar lake water is alkaline having pH around 9.3, in such alkaline environment, a cation-exchange reaction takes place. Furthermore, in saline water (16‰), salts can act as a shield and decrease the repulsive forces between clay particle surfaces. So, pH and salt content jointly impact the behaviour of clays differently. Since the Al-faces of clay structures have a negative charge in basic solutions. At high pH, all kaolinite surfaces become negative-charged, and then kaolinite

Pilot Test of a Novel Method for Assessing Community Response to Low-Amplitude Sonic Booms

Science.gov (United States)

Fidell, Sanford; Horonjeff, Richard D.; Harris, Michael

2012-01-01

A pilot test of a novel method for assessing residents annoyance to sonic booms was performed. During a two-week period, residents of the base housing area at Edwards Air Force Base provided data on their reactions to sonic booms using Smartphone-based interviews. Noise measurements were conducted at the same time. The report presents information about data collection methods and about test participants reactions to low-amplitude sonic booms. The latter information should not be viewed as definitive for several reasons. It may not be reliably generalized to the wider U.S. residential population (because it was not derived from a representative random sample) and the sample itself was not large.

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

International Nuclear Information System (INIS)

Rivard, C.; Pelletier, M.; Villieras, F.; Barres, O.; Galmiche, M.; Ghanbaja, J.; Kohler, A.; Michau, N.

2010-01-01

Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste it is of prime importance to understand the interactions between the saturated clay formation and steel containers. This can be achieved through an in-depth analysis of iron-clay interactions. Previous studies on the subject investigated the influence of solid/liquid ratio, iron/clay ratio, temperature and reaction time. The aim of the present study is to explain Callovo-Oxfordian-Fe(0) interactions by determining the role of each mineral phases present in the Callovo-Oxfordian (clay minerals, quartz, carbonates and pyrite) on the mechanisms of interaction between metal iron and clay particles. In that context, it is especially important to understand in detail the influence of clay nature and to obtain some insight about the relationships between interaction mechanisms at the molecular scale and crystallographic properties (particle size, TO or TOT layers, amount of edge faces...). The influence of the combination of different clays and the addition of other minerals must also be studied. In a first step, the Callovo-Oxfordian argillite from the Andra's underground research laboratory was purified to extract the clay fraction (illite, illite-smectite, kaolinite and chlorite). Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L -1 , CaCl 2 0.04 M.L -1 ) for durations of one, three or nine months in the presence of metallic iron powder. Experiments without iron were used as control. The iron/clay ratio was fixed at 1/3 with a solid/liquid ratio of 1/20. The above mentioned experiments were also carried out in parallel on other purified clays: two smectites (Georgia bentonite and SWy2 from the Clay Minerals Society), one illite (illite du Puy) and one kaolinite (KGa2, from the Clay Minerals society). At the end of the experiments, solid and liquid phases were

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

Energy Technology Data Exchange (ETDEWEB)

Elsen, A; Grobet, P; Keung, M; Leeman, H; Schoonheydt, R; Toufar, H [eds.

1995-08-20

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.

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

International Nuclear Information System (INIS)

Elsen, A.; Grobet, P.; Keung, M.; Leeman, H.; Schoonheydt, R.; Toufar, H.

1995-01-01

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

Status of LANL investigations of temperature constraints on clay in repository environments

International Nuclear Information System (INIS)

Caporuscio, Florie A.; Cheshire, Michael C.; Newell, Dennis L.; McCarney, Mary Kate

2012-01-01

The Used Fuel Disposition (UFD) Campaign is presently evaluating various generic options for disposal of used fuel. The focus of this experimental work is to characterize and bound Engineered Barrier Systems (EBS) conditions in high heat load repositories. The UFD now has the ability to evaluate multiple EBS materials, waste containers, and rock types at higher heat loads and pressures (including deep boreholes). The geologic conditions now available to the U.S.A. and the international community for repositories include saturated and reduced water conditions, along with higher pressure and temperature (P, T) regimes. Chemical and structural changes to the clays, in either backfill/buffer or clay-rich host rock, may have significant effects on repository evolution. Reduction of smectite expansion capacity and rehydration potential due to heating could affect the isolation provided by EBS. Processes such as cementation by silica precipitation and authigenic illite could change the hydraulic and mechanical properties of clay-rich materials. Experimental studies of these repository conditions at high P,T have not been performed in the U.S. for decades and little has been done by the international community at high P,T. The experiments to be performed by LANL will focus on the importance of repository chemical and mineralogical conditions at elevated P,T conditions. This will provide input to the assessment of scientific basis for elevating the temperature limits in clay barriers.

Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

Science.gov (United States)

Landrou, Gnanli; Brumaud, Coralie; Habert, Guillaume

2017-06-01

In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

Simplified High-Performance Roll Out Composite Magnetometer Boom, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In response to NASA's need for compact, low-cost deployable magnetometer booms for CubeSats, Roccor proposes to develop a Simple High-performance Roll-Out Composite...

Passenger Spaceplanes and Airplanes that Have Variable Configuration for Sonic Boom Reduction

Directory of Open Access Journals (Sweden)

Constantin SANDU

2018-06-01

Full Text Available In the last time, the interest for passenger space plane, supersonic passenger aircraft and supersonic business jets is increasing. For reducing sonic boom effects at ground level, some companies proposed airplanes having fuselage with small traversal section or having curved fuselage. This paper presents a new practical method for exciting vibrations in the leading edge of wing, tail and airplane's nose surfaces in order to scatter the shock wave and to reduce the sonic boom impact at ground level. The leading edges of wing, tail and airplane nose are covered with thin elastic fairings made of carbon fiber composite material which are separated through small gaps by the adjacent surfaces of wing, tail and nose. When the aircraft flies over populated areas, compressed air bleed from the engine compressors excites the vibration of carbon fiber fairings. The air is released through calibrated nozzles and directly impinges on the fairing surface generating their vibration. Thus, the shock waves are scattered and the impact of sonic boom on ground is much reduced.

THE SYNTHESIS OF Cr2O3-PILLARED MONTMORILLONITE (CrPM AND ITS USAGE FOR HOST MATERIAL OF p-NITROANILINE

Directory of Open Access Journals (Sweden)

Karna Wijaya

2010-06-01

Full Text Available The synthesis of Cr2O3-pillared montmorillonite (CrPM and its usage for host material of p-nitroaniline have been conducted. The Cr2O3-pillared montmorillonite clays was prepared by a direct ion exchange method. First, the polyhydroxychromium as a pillaring spesies was intercalated into the interlayer region of the montmorillonite clays (purified clay in the monocation form, result in a montmorillonite-polyoxychromium intercalation compound. The precursors/pillaring spesies was not stable, hence it must be stabilized by calcination in order to transform the polyoxychromium via dehydration and dehydroxylation processes into Cr2O3. This oxide constituts the so-called pillar that prop the clay layers apart to a relatively large distance. The Cr2O3-pillared clays as a host material was added into ethanol solution saturated with p-nitroaniline, and mixture was stirred for 24 h at room temperature. The Na-montmorillonite, Cr2O3-pillared clay and p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM were characterized by X-Ray Diffraction (XRD, Gas Sorption Analysis, Infrared Spectroscopy (FTIR and Activated Neutron Analysis (ANA methods. The result of research showed that basal spacing (d001 of Cr2O3-pillared montmorillonite (CrPM was 18,55 Å, meanwhile the basal spacing of the hydrated Na-montmorillonite was 14,43 Å. The specific surface area of the Cr2O3-pillared montmorillonite was 174,308 m2/g, whereas p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM was 133,331641 m2/g. This fact indicated that p-nitroaniline has been included into the pore of the Cr2O3-pillared clay.   Keyword: montmorillonite, pillared-clay, ion exchange, intercalate.

Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations

Science.gov (United States)

Yew, Alvin G.; Chai, Dean J.; Olney, David J.

2010-01-01

The goal of NASA's Magnetospheric MultiScale (MMS) mission is to understand magnetic reconnection with sensor measurements from four spinning satellites flown in a tight tetrahedron formation. Four of the six electric field sensors on each satellite are located at the end of 60- meter wire booms to increase measurement sensitivity in the spin plane and to minimize motion coupling from perturbations on the main body. A propulsion burn however, might induce boom oscillations that could impact science measurements if oscillations do not damp to values on the order of 0.1 degree in a timely fashion. Large damping time constants could also adversely affect flight dynamics and attitude control performance. In this paper, we will discuss the implementation of a high resolution method for calculating the boom's intrinsic damping, which was used in multi-body dynamics simulations. In summary, experimental data was obtained with a scaled-down boom, which was suspended as a pendulum in vacuum. Optical techniques were designed to accurately measure the natural decay of angular position and subsequently, data processing algorithms resulted in excellent spatial and temporal resolutions. This method was repeated in a parametric study for various lengths, root tensions and vacuum levels. For all data sets, regression models for damping were applied, including: nonlinear viscous, frequency-independent hysteretic, coulomb and some combination of them. Our data analysis and dynamics models have shown that the intrinsic damping for the baseline boom is insufficient, thereby forcing project management to explore mitigation strategies.

GRS' research on clay rock in the Mont Terri underground laboratory

Energy Technology Data Exchange (ETDEWEB)

Wieczorek, Klaus; Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit gGmbH, Braunschweig (Germany)

2016-07-15

For constructing a nuclear waste repository and for ensuring the safety requirements are met over very long time periods, thorough knowledge about the safety-relevant processes occurring in the coupled system of waste containers, engineered barriers, and the host rock is indispensable. For respectively targeted research work, the Mont Terri rock laboratory is a unique facility where repository research is performed in a clay rock environment. It is run by 16 international partners, and a great variety of questions are investigated. Some of the work which GRS as one of the Mont Terri partners is involved in is presented in this article. The focus is on thermal, hydraulic and mechanical behaviour of host rock and/or engineered barriers.

A study of sonic boom overpressure trends with respect to weight, altitude, Mach number, and vehicle shaping

Science.gov (United States)

Needleman, Kathy E.; Mack, Robert J.

1990-01-01

This paper presents and discusses trends in nose shock overpressure generated by two conceptual Mach 2.0 configurations. One configuration was designed for high aerodynamic efficiency, while the other was designed to produce a low boom, shaped-overpressure signature. Aerodynamic lift, sonic boom minimization, and Mach-sliced/area-rule codes were used to analyze and compute the sonic boom characteristics of both configurations with respect to cruise Mach number, weight, and altitude. The influence of these parameters on the overpressure and the overpressure trends are discussed and conclusions are given.

Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

Directory of Open Access Journals (Sweden)

Landrou Gnanli

2017-01-01

Full Text Available In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

In situ corrosion tests on HLW glass as part of a larger approach

International Nuclear Information System (INIS)

Van Iseghem, P.

1997-01-01

In-situ corrosion tests were performed on various candidate high-level waste glasses in the underground laboratory in clay underneath SCK x CEN. The tests exposed the glass samples directly to the Boom clay rock, for maximum durations of 7.5 years. We succeeded to interpret the corrosion data at 90 deg C in terms of dissolution mechanisms, and we concluded that the glass composition has a determining effect on the corrosion stability. The data from our in-situ tests were of high relevance for estimating the long-term behaviour of the glasses. The long-term in-situ tests provide corrosion data which show different trends than other corrosion tests, e.g. shorter duration tests in Boom clay, or tests in deionized water. The initial dissolution rate using MCC1 test at 90 deg C is about the same for the three glasses discussed, but the longest duration in Boom clay at 90 deg C shows a difference in mass loss of about 25 times. We finally present some ideas on how the corrosion tests can meet the needs, such as the modelling of the glass corrosion or providing input in the performance assessment. (author)

Synthesis of templated carbons starting from clay and clay-derived zeolites for hydrogen storage applications

CSIR Research Space (South Africa)

Musyoka, Nicholas M

2014-10-01

Full Text Available 57 58 59 60 For Peer Review 1 Synthesis of templated carbons starting from clay and clay-derived zeolites for hydrogen storage applications N. M. Musyoka1*, J. Ren1, H. W. Langmi1, D. E. C. Rogers1, B. C. North1, M. Mathe1 and D. Bessarabov2... clear (filtered) extract of cloisite clay, SNC for zeolite from unfiltered cloisite clay extract and SBC for zeolite from unfiltered South African bentonite clay extract. Furfuryl alcohol (Sigma Aldrich, C5H6O2, 98%) and Ethylene gas were used...

The Control of Welding Deformation of the Three-Section Arm of Placing Boom of HB48B Pump Truck

Science.gov (United States)

Wang, Zhi-ling

2018-02-01

The concrete pump truck is the construction equipment of conveying concrete with self contained base plate and distributing boom. It integrates the pump transport mechanism of the concrete pump, and the hydraulic roll-folding type distributing boom used to distribute materials, and the supporting mechanism into the automobile chassis, and it is the concrete conveying equipment with high efficient and the functions of driving, pumping, and distributing materials. The placing boom of the concrete pump truck is the main force member in the pump parts with bearing great pressure, and its stress condition is complex. Taking the HB48B placing boom as an example, this paper analyzes and studies the deformation produced by placing boom of pump truck, and then obtains some main factors affecting the welding deformation. Through the riveter “joint” size, we controlled the process parameters, post-welding processing, and other aspects. These measures had some practical significance to prevent, control, and reduce the deformation of welding.

Possibility of disposing of conditioned nuclear waste in deep-lying clay formations

International Nuclear Information System (INIS)

Bonne, A.; Heremans, R.; Vandenberghe, N.

1980-01-01

Among the host rock types suitable for final disposal of nuclear waste, argillaceous formations display distinct advantages and disadvantages. In the present paper some of them will be examined. In order to render conceivable the possibilities for disposing of radwastes into a plastic clay formation, some main items of the Belgian R and D-programme in that matter will be discussed (site and rock investigation, conceptual design and feasibility, and risk analysis). (Auth.)

Mobility of zinc in the Callovo-Oxfordian clay-stone

Energy Technology Data Exchange (ETDEWEB)

Savoye, S.; Fayette, A.; Beaucaire, C. [CEA, DEN, DPC, SECR, L3MR, F-91191 Gif s/Yvette (France); Lacour, J.-L. [CEA, DEN, DPC, SEARS, LANIE, F-91191 Gif s/Yvette (France)

2013-07-01

The diffusion of zinc was studied in the Callovo-Oxfordian clay-stone, which is a potential host rock for the retrievable disposal of high-level radioactive wastes. Two in-diffusion laboratory experiments were performed with initial zinc concentrations of 4 10{sup -5} mol L{sup -1} and 8 10{sup -6} mol L{sup -1} (resp.) for 35 days. The zinc rock profile was acquired using an original technique, the μLIBS, with a high resolution (10 μm), calibrated with the abrasive peeling method. The experimental data, i.e. Zn concentration monitoring in the source reservoir and Zn rock profile, were successfully reproduced using a chemical-transport code. In that code, the sorption of Zn was described by a multi-site ion-exchange model, with only the effective diffusion coefficient value being adjusted (De = 8 10{sup -11} m{sup 2} s{sup -1}). This De value, 2 times higher than that of tritiated water, indicates that zinc, like most cations, is also subject to enhanced diffusion in clay rocks. (authors)

Research of Deformation of Clay Soil Mixtures Mixtures

OpenAIRE

Romas Girkontas; Tadas Tamošiūnas; Andrius Savickas

2014-01-01

The aim of this article is to determine clay soils and clay soils mixtures deformations during drying. Experiments consisted from: a) clay and clay mixtures bridges (height ~ 0,30 m, span ~ 1,00 m); b) tiles of clay and clay, sand and straw (height, length, wide); c) cylinders of clay; clay and straw; clay, straw and sand (diameter; height). According to the findings recommendations for clay and clay mixtures drying technology application were presented. During the experiment clay bridge bear...

Numerical analysis of thermo-hydro-mechanical (THM) processes in the clay based material

Energy Technology Data Exchange (ETDEWEB)

Wang, Xuerui

2016-10-06

Clay formations are investigated worldwide as potential host rock for the deep geological disposal of high-level radioactive waste (HLW). Usually bentonite is preferred as the buffer and backfill material in the disposal system. In the disposal of HLW, heat emission is one of the most important issues as it can generate a series of complex thermo-hydro-mechanical (THM) processes in the surrounding materials and thus change the material properties. In the context of safety assessment, it is important to understand the thermally induced THM interactions and the associated change in material properties. In this work, the thermally induced coupled THM behaviours in the clay host rock and in the bentonite buffer as well as the corresponding coupling effects among the relevant material properties are numerically analysed. A coupled non-isothermal Richards flow mechanical model and a non-isothermal multiphase flow model were developed based on the scientific computer codes OpenGeoSys (OGS). Heat transfer in the porous media is governed by thermal conduction and advective flow of the pore fluids. Within the hydraulic processes, evaporation, vapour diffusion, and the unsaturated flow field are considered. Darcy's law is used to describe the advective flux of gas and liquid phases. The relative permeability of each phase is considered. The elastic deformation process is modelled by the generalized Hooke's law complemented with additional strain caused by swelling/shrinkage behaviour and by temperature change. In this study, special attention has been paid to the analysis of the thermally induced changes in material properties. The strong mechanical and hydraulic anisotropic properties of clay rock are described by a transversely isotropic mechanical model and by a transversely isotropic permeability tensor, respectively. The thermal anisotropy is described by adoption of the bedding-orientation-dependent thermal conductivity. The dependency of the thermal

Numerical analysis of thermo-hydro-mechanical (THM) processes in the clay based material

International Nuclear Information System (INIS)

Wang, Xuerui

2016-01-01

Clay formations are investigated worldwide as potential host rock for the deep geological disposal of high-level radioactive waste (HLW). Usually bentonite is preferred as the buffer and backfill material in the disposal system. In the disposal of HLW, heat emission is one of the most important issues as it can generate a series of complex thermo-hydro-mechanical (THM) processes in the surrounding materials and thus change the material properties. In the context of safety assessment, it is important to understand the thermally induced THM interactions and the associated change in material properties. In this work, the thermally induced coupled THM behaviours in the clay host rock and in the bentonite buffer as well as the corresponding coupling effects among the relevant material properties are numerically analysed. A coupled non-isothermal Richards flow mechanical model and a non-isothermal multiphase flow model were developed based on the scientific computer codes OpenGeoSys (OGS). Heat transfer in the porous media is governed by thermal conduction and advective flow of the pore fluids. Within the hydraulic processes, evaporation, vapour diffusion, and the unsaturated flow field are considered. Darcy's law is used to describe the advective flux of gas and liquid phases. The relative permeability of each phase is considered. The elastic deformation process is modelled by the generalized Hooke's law complemented with additional strain caused by swelling/shrinkage behaviour and by temperature change. In this study, special attention has been paid to the analysis of the thermally induced changes in material properties. The strong mechanical and hydraulic anisotropic properties of clay rock are described by a transversely isotropic mechanical model and by a transversely isotropic permeability tensor, respectively. The thermal anisotropy is described by adoption of the bedding-orientation-dependent thermal conductivity. The dependency of the thermal

Leading the next boom? competitive Eastern limb platinum supply

CSIR Research Space (South Africa)

McGill, JE

2010-07-01

Full Text Available in USD/troy oz (Data source: Johnson Matthey) Figure 4. Variation in nominal PGEs spot price from July 1992 till July 2010 in USD/troy oz (Data source: Johnson Matthey) PLATINUM IN TRANSITION ?BOOM OR BUST?4 each. In 1996 and 2003 merger attempts...

Drilling Down: An Examination of the Boom-Crime Relationship in Resource Based Boom Counties

Directory of Open Access Journals (Sweden)

Rick Ruddell

2017-03-01

Full Text Available Objective to examine the boomcrime relationship in resourcebased boom counties and to propose socioeconomic and legal measures to reduce the boomtown effect. Methods dialectical approach to cognition of social phenomena allowing to analyze them in historical development and functioning in the context of the totality of objective and subjective factors that determined the choice of the following research methods formallogical comparativelegal survey interview focus groups generalized least squares method. Results The expansion in natural resource development in rural communities has led to a number of social problems in these places. The media community stakeholders as well as law enforcement and human service personnel have reported that the rapid growth in these communities leads to increased crime and other social ills. In order to better understand the boomcrime relationship index crimes in oil and natural gas producing counties in Montana and North Dakota were examined. Comparison of 2012 crime rates in a matched sample of counties revealed that crime rates were higher in oilimpacted counties. A prepost analysis found that violent crime in boom counties increased 18.5 between 2006 and 2012 while decreasing 25.6 in a matched sample of counties that had no oil or gas production. Inconsistent with the media portrayal of these communities as a new quotwild westquot we did not find a significant association between oil or natural gas production and property or violent crime in a series of OLS regression models. Scientific novelty for the first time the article uses index crimes in oil and natural gas producing counties in Montana and North Dakota to reveal the association between the rapid growth of towns and the crime rates. Practical significance the main provisions and conclusions of the article can be used in research and educational activity as well as for predicting the socialeconomic development of boomtowns.

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

Energy Technology Data Exchange (ETDEWEB)

Monasterio, Fernanda E.; Carrera, Maria C.; Erdmann, Eleonora; Destefanis, Hugo A., E-mail: ferelenakq@gmail.co [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina). Inst. de Investigaciones para la Industria Quimica; Pita, Victor J.R.R.; Dias, Marcos L. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

2009-07-01

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

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

International Nuclear Information System (INIS)

Monasterio, Fernanda E.; Carrera, Maria C.; Erdmann, Eleonora; Destefanis, Hugo A.; Pita, Victor J.R.R.; Dias, Marcos L.

2009-01-01

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

The Iron Law of Financial Markets: Self-fulfilling Prophecies and Speculative Booms and Busts

Directory of Open Access Journals (Sweden)

Ognjen Radonjić

2016-02-01

Full Text Available This paper discusses the factors which, in the absence of strong financial regulation, sustain the Iron Law of the Financial Markets asserting that speculative booms and busts occur more or less regularly from 17 century to the present. The first factor is that financial markets are self-fulfilling system. The second is that human nature does not change and is based on egoism, materialism, loss aversion, exaggerated hopes and fears, emulation, propensity to gamble, herd behavior and so on. Lastly, there is the extreme brevity of the financial memory. In order to enable economic authorities and/or individuals to detect timely that the unsustainable boom is under the way, we have identified the common features of historically recorded speculative episodes. Stages through which the system passes on its way from unsustainable rise to inevitable fall are: displacement, boom, overtrading, financial distress and discredit or revulsion.

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.

Safety- and performance indicators for a generic deep geological repository in clay

International Nuclear Information System (INIS)

Resele, G.; Niemeyer, M.; Wilhelm, St.; Heimer, St.; Mohlfeld, M.; Eilers, G.; Preuss, J.; Wollrath, J.

2010-01-01

Document available in extended abstract form only. As a first step of an impartial survey for an optimal site selection for a deep geological repository in Germany, potentially suitable regions shall be identified and localised according to their suitability. During the early phases of such a site selection procedure the information about the properties of the host rock and the geological situation at the potential sites is not very precise. As site investigation procedures are both expensive and time-consuming, it is essential to identify those properties of the geological barrier system that are most relevant for long-term safety. Furthermore, adequate indicators have to be chosen that allow a simple but efficient assessment of the suitability of the potential regions. Definition and application of 'exclusion criteria' based on single parameter values, e.g. the hydraulic conductivity of the host rock, is inadequate because the long-term safety depends on the interaction of many features and properties of the barrier system. In a research project, indicators have been developed which depend on the most relevant properties of the geological barriers and estimate the overall performance of a repository system. The application of these indicators on the barrier properties which have been found during the investigations of potential repository sites in clay located in Germany, Switzerland and France demonstrates how, for instance, an unfavourably high hydraulic permeability of the clay can be compensated by a large vertical extension of the clay layer and small hydraulic gradients. Other indicators evaluate the importance of hydraulic discontinuities and define the minimal requirements on technical barriers like seals and backfill of emplacement tunnels. When the information of the radionuclide inventory and the biosphere, especially the diluting aquifer is included, the indicators allow the estimation of the resulting dose which matches the result of a

Aspects of clay/concrete interactions

International Nuclear Information System (INIS)

Oscarson, D.W.; Dixon, D.A.; Onofrei, M.

1997-01-01

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 85 o C with up to 5 wt.% Ca(OH) 2 , compacted bentonite (dry density = 1.2 Mg/m 3 ) 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

Physical Properties of Latvian Clays

OpenAIRE

Jurgelāne, I; Stepanova, V; Ločs, J; Mālers, J; Bērziņa-Cimdiņa, L

2012-01-01

Physical and chemical properties of clays mostly depends on its mineral and chemical composition, particle size and pH value. The mutual influence of these parameters is complex. Illite is the most abundant clay mineral in Latvia and usually used in building materials and pottery. The viscosity and plasticity of Latvian clays from several deposits were investigated and correlated with mineral composition, particle size and pH value. Fractionated and crude clay samples were used. The p...

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

International Nuclear Information System (INIS)

Bleyen, N.; Smets, S.; Valcke, E.; Albrecht, A.; De Canniere, P.; Schwyn, B.; Wittebroodt, C.

2012-01-01

Document available in extended abstract form only. In several countries, such as Belgium, France and Switzerland, clay formations are foreseen as the host rock for geological disposal of bituminized low-level and intermediate-level long-lived radioactive waste. Suitable clay formations exhibit favorable hydro-mechanical and geochemical characteristics, which are expected to retard the migration of leached radionuclides. Along with radionuclides, certain classes of bituminized radioactive waste may also contain high concentrations of NaNO 3 , dispersed into the hydrophobic bitumen matrix used to stabilize the waste. During and after saturation of the disposal gallery, this bituminized waste will start to take up water due to osmosis, resulting in the leaching of significant amounts of NaNO 3 and soluble organic bitumen degradation products (BDP) into the clay pore water. This nitrate plume could cause several geochemical and biochemical processes in the clay surrounding the waste disposal gallery, potentially affecting the barrier function of the host rock. To study these processes, an in situ experiment in the Opalinus Clay, named the Bitumen-Nitrate-Clay interaction (BN) experiment, is being performed at the Mont Terri Rock Laboratory (CH). The experiment consists of a vertical borehole rigged with a downhole equipment containing three packed-off intervals, each lined with a cylindrical sintered stainless steel filter screen to allow contact with the surrounding clay. Prior to the start of the tests, the intervals were injected with an artificial Opalinus Clay pore water, containing all major ions at pore water concentrations at Mont Terri, but no organic matter, and were equilibrated with the surrounding clay for ∼8 months. To ensure a continuous water flow during the tests, each interval is connected to a stainless steel water circulation unit, equipped with water sampling containers, circulation pumps and flow meters. In addition, to continuously monitor the

Physical model of a floating trash boom to control aquatic weeds at the TVA Widows Creek Fossil Plant

International Nuclear Information System (INIS)

Hopping, P.N.

1991-01-01

This paper reports that the Tennessee Valley Authority (TVA) Widows Creek Fossil plant seasonally encounters adverse accumulations of aquatic weeds at the intakes of the condenser cooling water pumps. To reduce the accumulations, a floating trash boom has been proposed for the intakes. To evaluate the hydraulic feasibility of a boom, a physical model of the intakes has been built at the TVA Engineering Laboratory. The model was used to determine the boom alignment and depth of skimming needed to successfully deflect weeds away from the intakes and provide self-cleaning

Prisons as Panacea or Pariah? The Countervailing Consequences of the Prison Boom on the Political Economy of Rural Towns

Directory of Open Access Journals (Sweden)

John M. Eason

2017-01-01

Full Text Available The nascent literature on prison proliferation in the United States typically reveals negative impacts for communities of color. Given that Southern rural communities were the most likely to build during the prison boom (1970–2010, however, a more nuanced understanding of prison impact is warranted. Using a dataset matching and geocoding all 1663 U.S. prisons with their Census-appointed place, this study explores the countervailing consequences of the prison boom on rural towns across multiple periods. For example, locales that adopted prisons at earlier stages of the prison boom era received a short-term boom compared to those that did not, but these effects were not lasting. Furthermore, later in the boom, prison-building protected towns against additional economic decline. Thus, neither entirely pariah nor panacea, the prison functions as a state-sponsored public works program for disadvantaged rural communities but also supports perverse economic incentives for prison proliferation. Methodological, substantive, theoretical, and policy implications regarding the intersection of race and punishment are explored.

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.

Evaluation of the bleaching flux in clays containing hematite and different clay minerals

International Nuclear Information System (INIS)

Silva Junior, E.M.; Lusa, T.; Silva, T.M.; Medeiros, B.B.; Santos, G.R. dos; Morelli, M.R.

2016-01-01

Previous studies have shown that the addition of a synthetic flux in a clay mineral constituted by illite phase in the presence of iron oxide with the hematite, promotes color change of the firing products, making the reddish color firing into whiteness. This flow is constituted of a vitreous phase of the silicates family obtained by fusion/solidification of oxides and carbonates. Thus, the objective of this work was that of studying the interaction of the iron element in the final color mechanism of the different types of mineral crystal phase of the clays. In order to study the phenomenon, we obtained different compositions between the select clays and the synthetic flow, and characterization using X-ray diffraction (XRD) and visual analysis. The results showed that the action of the synthetic flow as a modifying agent for color depends on the mineral crystal phase of the clays. The color firing modification does not occur in the clays content high levels of kaolinite mineral phase. (author)

Columns in Clay

Science.gov (United States)

Leenhouts, Robin

2010-01-01

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

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

Evaluation of Used Fuel Disposition in Clay-Bearing Rock

Energy Technology Data Exchange (ETDEWEB)

Jove-Colon, Carlos F.; Weck, Philippe F.; Sassani, David Carl; Zheng, Liange; Rutqvist, Jonny; Steefel, Carl I.; Kim, Kuhhwi; Nakagawa, Seiji; Houseworth, James; Birkholzer, Jens T.; Caporuscio, Florie Andre; Cheshire, Michael; Rearick, Michael; McCarney, Mary K.; Zavarin, Mavrik; Benedicto, Ana; Kersting, Annie B.; Sutton, Mark.; Jerden, James L.; Frey, Kurt E.; Copple, Jacqueline M.; Ebert, William L.

2014-08-01

Radioactive waste disposal in shale/argillite rock formations has been widely considered given its desirable isolation properties (low permeability), geochemically reduced conditions, anomalous groundwater pressures, and widespread geologic occurrence. Clay/shale rock formations are characterized by their high content of clay minerals such as smectites and illites where diffusive transport and chemisorption phenomena predominate. These, in addition to low permeability, are key attributes of shale to impede radionuclide mobility. Shale host-media has been comprehensively studied in international nuclear waste repository programs as part of underground research laboratories (URLs) programs in Switzerland, France, Belgium, and Japan. These investigations, in some cases a decade or more long, have produced a large but fundamental body of information spanning from site characterization data (geological, hydrogeological, geochemical, geomechanical) to controlled experiments on the engineered barrier system (EBS) (barrier clay and seals materials). Evaluation of nuclear waste disposal in shale formations in the USA was conducted in the late 70’s and mid 80’s. Most of these studies evaluated the potential for shale to host a nuclear waste repository but not at the programmatic level of URLs in international repository programs. This report covers various R&D work and capabilities relevant to disposal of heat-generating nuclear waste in shale/argillite media. Integration and cross-fertilization of these capabilities will be utilized in the development and implementation of the shale/argillite reference case planned for FY15. Disposal R&D activities under the UFDC in the past few years have produced state-of-the-art modeling capabilities for coupled Thermal-Hydrological-Mechanical-Chemical (THMC), used fuel degradation (source term), and thermodynamic modeling and database development to evaluate generic disposal concepts. The THMC models have been developed for shale

Effects of Different Types of Clays and Maleic Anhydride Modified Polystyrene on Polystyrene/Clay Nanocomposites

Directory of Open Access Journals (Sweden)

M. Mehrabzadeh

2013-01-01

Full Text Available Polymer/clay nanocomposites are considered as a new subject of research in Iran and the world. Addition of a minimum amount of clay (2-5wt% can improve the mechanical properties, enhance barrier properties and reduce flammability dramatically. Polystyrene (PS exhibits high strength, high modulus and excellent dimensional stability, but it has poor ductility, elongation, and flexural modulus. By incorporating clay into polystyrene these properties can be improved. In this study preparation of polystyrene/clay nanocomposite, effects of different types of clays (Cloisite 10A andNanomer I.30TC and maleic anhydride modified polystyrene on mechanical properties of the prepared polystyrene/clay nanocomposites were evaluated. Samples were prepared by a twin screw extruder. Transmission electron microscopy (TEM and X-ray diffraction (XRD techniques were employed to evaluate the extent of intercalation and exfoliation of silicate layers in the nanocomposites. Mechanical tests show that by addition of clay and maleic anhydride modified polystyrene the flexural modulus (~30% and elongation-at-break (~40% of prepared nanocomposites have been improved. XRD and TEM results show that nanocomposite have an intercalated structure with ability to change to further exfoliation structure.

Thixotropic Properties of Latvian Illite Containing Clays

OpenAIRE

Lakevičs, Vitālijs; Stepanova, Valentīna; Niedra, Santa; Dušenkova, Inga; Ruplis, Augusts

2015-01-01

Thixotropic properties of Latvian Devonian and Quaternary clays were studied. Dynamic viscosity of the water clay suspensions were measured with a rotating viscometer. Influence of concentration, pH and modifiers on the thixotropic clay properties was analyzed. It was found that Latvian clays have thixotropic properties. Stability of clay suspensions is described with the thixotropy hysteresis loop. Increasing the speed of the viscometer rotation, dynamic viscosity of the clay suspension decr...

Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

Directory of Open Access Journals (Sweden)

Simona eLongo

2013-11-01

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

Modelling of the mechanical behaviour and damage of clay-stones: application to the East argillite

International Nuclear Information System (INIS)

Aublive-Conil, N.

2003-03-01

The storage in deep geological formation is one of the solutions retained by France for the management of highly long life radioactive waste. The retained host rock is a clay-stone named East argillite located in the departments of Meuse and Haute-Marne. A thermodynamic formulation is used to propose a rheological model, which reproduces the mechanical behavior of clay-stones. Initially, an anisotropic damage plastic model was formulated in order to describe material degradations. Then, the damage plastic model is reformulated in order to taken into account the damage influence on the hydraulic behavior of porous material. The numerical simulations correctly reproduce the mechanical behavior of East Argillites but also the anisotropy of the hydraulic behavior introduced by the damage effect. (author)

Seagrass Control Project: Containment Boom Evaluation. A Method to Protect Seawater Intakes from Seagrass Accumulation.

Science.gov (United States)

1983-10-01

containment booms at other mooring sites with significantly different physical and environ- mental conditions is recommended before full-scale application...deployment pattern for the different ship types. Modified procedures may also be needed to deploy the boom under a different set of physical and environmental... STPM Press Publ. New York, 353pp. 1980. Pulich, W., S. Barnes and P. Parker. Trace metal cycles in seagrass communities. pp 493-506 in M. Wiley, ed

What makes a natural clay antibacterial?

Science.gov (United States)

Williams, Lynda B.; Metge, David W.; Eberl, Dennis D.; Harvey, Ronald W.; Turner, Amanda G.; Prapaipong, Panjai; Port-Peterson, Amisha T.

2011-01-01

Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial clays contain nanoscale (2+ solubility.

Viscosity and Plasticity of Latvian Illite Clays

OpenAIRE

Jurgelāne, I; Vecstaudža, J; Stepanova, V; Mālers, J; Bērziņa-Cimdiņa, L

2012-01-01

Due to viscosity and plasticity, clays and clay minerals are used in civil engineering, pottery and also in cosmetics and medicine as thickening agents and emulsion and suspension stabilizers. The rheological properties of clay suspensions are complex. Mostly it is an interaction between mineral composition, clay particle size and pH value and also depends on clay minerals. Clay-water suspension is non-Newtonian fluid showing thixotropic and pseudoplastic properties. Results showed that plast...

Modeling and simulation of the agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian; Miao, Yubin

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the application process. Thus we can

Experimental Investigation of a Large-Scale Low-Boom Inlet Concept

Science.gov (United States)

Hirt, Stefanie M.; Chima, Rodrick V.; Vyas, Manan A.; Wayman, Thomas R.; Conners, Timothy R.; Reger, Robert W.

2011-01-01

A large-scale low-boom inlet concept was tested in the NASA Glenn Research Center 8- x 6- foot Supersonic Wind Tunnel. The purpose of this test was to assess inlet performance, stability and operability at various Mach numbers and angles of attack. During this effort, two models were tested: a dual stream inlet designed to mimic potential aircraft flight hardware integrating a high-flow bypass stream; and a single stream inlet designed to study a configuration with a zero-degree external cowl angle and to permit surface visualization of the vortex generator flow on the internal centerbody surface. During the course of the test, the low-boom inlet concept was demonstrated to have high recovery, excellent buzz margin, and high operability. This paper will provide an overview of the setup, show a brief comparison of the dual stream and single stream inlet results, and examine the dual stream inlet characteristics.

Clay Portrait Boxes

Science.gov (United States)

Wilbert, Nancy Corrigan

2009-01-01

In an attempt to incorporate sculptural elements into her ceramics program, the author decided to try direct plaster casting of the face to make a plaster mold for clay. In this article, the author shares an innovative ceramics lesson that teaches students in making plaster casts and casting the face in clay. This project gives students the…

Clay matrix voltammetry

International Nuclear Information System (INIS)

Perdicakis, Michel

2012-01-01

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 (FeS 2 ), 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

Preliminary analysis of construction of the test drift in boom clay at Mol using plasticity solutions and finite elements

International Nuclear Information System (INIS)

Mair, R.J.; Taylor, R.N.; Higgins, K.G.; Potts, D.M.

1989-01-01

Analyses have been undertaken on an advancing tunnel heading at great depth in a clay formation corresponding to the test drift construction at Mol. Belgium. Simplifying assumptions enable plasticity solutions to be used to model the behaviour of a tunnel heading in a linear elastic-perfectly plastic soil. Finite element analysis with the same soil model has been undertaken of the test drift construction, assuming axisymmetric conditions. The results are compared with the plasticity solutions and with the measurements of lining stresses, soil movements and pore pressures by SCK/CEN. Good agreement is obtained between the plasticity solutions and finite element analysis. The measured immediate build-up of stress on the linings is well-predicted and reasonable agreement is obtained between predicted and measured soil movements. The measured pore-pressure changes are poorly predicted by the analyses

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…

Anisotropic Behaviour of Opalinus Clay Through Consolidated and Drained Triaxial Testing in Saturated Conditions

Science.gov (United States)

Favero, Valentina; Ferrari, Alessio; Laloui, Lyesse

2018-05-01

This paper investigates the anisotropic hydro-mechanical behaviour of Opalinus Clay shale, the host material currently being considered for the construction of a nuclear waste repository in Switzerland. Consolidated and drained triaxial tests on Opalinus Clay from the Mont Terri URL have been conducted in order to derive information on its strength and stiffness properties. Opalinus Clay specimens were tested both parallel to bedding (P-specimens) and perpendicular to bedding (S-specimens). The considered effective confining stress range (from 2 to 12 MPa) has been selected in order to reproduce possible in situ stress conditions for the repository. In this work, particular attention has been paid to the experimental procedure in order to ensure consolidated conditions and avoid generation of unwanted excess pore water pressure during drained shearing. The Skempton B parameter has been determined for all the tested specimens in order to ensure saturation. Both single-stage and multistage triaxial testing procedures were adopted in the experimental campaign. The results of the triaxial tests highlight an anisotropic elastic response of Opalinus Clay: S-specimens present a more compliant behaviour than P-specimens. The values of the Young modulus are found to increase with the increase in mean effective stress. The analysis of the peak and ultimate shear strength results reveals that the material behaves in a similar manner regardless of the considered direction of loading (P and S directions) with respect to the bedding orientation. Peak and ultimate failure envelopes for Opalinus Clay were derived for the investigated stress range.

Surface modification of montmorillonite on surface Acid-base characteristics of clay and thermal stability of epoxy/clay nanocomposites.

Science.gov (United States)

Park, Soo-Jin; Seo, Dong-Il; Lee, Jae-Rock

2002-07-01

In this work, the effect of surface treatments on smectitic clay was investigated in surface energetics and thermal behaviors of epoxy/clay nanocomposites. The pH values, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the effect of cation exchange on clay surface and the exfoliation phenomenon of clay interlayer. The surface energetics of clay and thermal properties of epoxy/clay nanocomposites were investigated in contact angles and thermogravimetric analysis (TGA), respectively. From the experimental results, the surface modification of clay by dodecylammonium chloride led to the increases in both distance between silicate layers of about 8 A and surface acid values, as well as in the electron acceptor component (gamma(+)(s)) of surface free energy, resulting in improved interfacial adhesion between basic (or electron donor) epoxy resins and acidic (electron acceptor) clay interlayers. Also, the thermal stability of nanocomposites was highly superior to pure epoxy resin due to the presence of the well-dispersed clay nanolayer, which has a barrier property in a composite system.

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) contain...

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

DEFF Research Database (Denmark)

Sørensen, Morten Kanne; Fabricius, Ida Lykke

2013-01-01

Compliant porosity in the form of cracks is known to cause significant attenuation and velocity dispersion through pore pressure gradients and consequent relaxation, dubbed squirt flow. Squirt flow from cracks vanish at high confining stress due to crack closing. Studies on clay bearing sandstones......-squirt flow on the bulk modulus of a clay bearing sandstone. The predicted magnitude of the clay-squirt effect on the bulk modulus is compared with experimental data. The clay-squirt effect is found to possibly account for a significant portion of the deviances from Gassmann fluid substitution in claybearing...... sandstones....

A partial braincase and other skeletal remains of Oligocene angel sharks (Chondrichthyes, Squatiniformes) from northwest Belgium, with comments on squatinoid taxonomy

NARCIS (Netherlands)

Mollen, F.H.; Bakel , van B.W.M.; Jagt, J.W.M.

2016-01-01

A detailed redescription of a chondrocranium from the basal Boom Clay Formation (Rupelian, Upper Oligocene) at the SVK clay pit, Sint-Niklaas (province of Oost-Vlaanderen, Belgium), previously assigned to the sawshark Pristiophorus rupeliensis, is presented. The chondrocranium is re-identified as

Design of an Indoor Sonic Boom Simulator at NASA Langley Research Center

Science.gov (United States)

Klos, Jacob; Sullivan, Brenda M.; Shepherd, Kevin P.

2008-01-01

Construction of a simulator to recreate the soundscape inside residential buildings exposed to sonic booms is scheduled to start during the summer of 2008 at NASA Langley Research Center. The new facility should be complete by the end of the year. The design of the simulator allows independent control of several factors that create the indoor soundscape. Variables that will be isolated include such factors as boom duration, overpressure, rise time, spectral shape, level of rattle, level of squeak, source of rattle and squeak, level of vibration and source of vibration. Test subjects inside the simulator will be asked to judge the simulated soundscape, which will represent realistic indoor boom exposure. Ultimately, this simulator will be used to develop a functional relationship between human response and the sound characteristics creating the indoor soundscape. A conceptual design has been developed by NASA personnel, and is currently being vetted through small-scale risk reduction tests that are being performed in-house. The purpose of this document is to introduce the conceptual design, identify how the indoor response will be simulated, briefly outline some of the risk reduction tests that have been completed to vet the design, and discuss the impact of these tests on the simulator design.

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

Evaluation of kaolinite clays of Moa for the production of cement based clinker-calcined clay-limestone (LC3

Directory of Open Access Journals (Sweden)

Roger S. Almenares-Reyes

2016-12-01

Full Text Available Clay materials from two outcrops of the Moa region were analyzed to determine their potential use as supplementary cementitious material in the production of ternary cements based on limestone-calcined clay. The clays were characterized by atomic absorption spectroscopy (EAA, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (ATG. These methods revealed high aluminum in clays, moderate kaolinite content, a disordered structure and the presence of impurities. The solubility of aluminum and silicon in alkali and the compressive strength of LC3 systems is proportional to their content in clay, being higher for the one with higher kaolinite content and greater structural disorder (outcrop D1, although the clay of both outcrops may constitute supplementary cementitious materials in the production of ternary cements based clinker-calcined clay-limestone. The suitable thermal activation range for both clays is between 650 ° C and 850 ° C.

Geological evolution of clay sediments: the petroleum exploration vision

International Nuclear Information System (INIS)

Schneider, F.

2004-01-01

The radioactive waste isolation capacity assessment for a clay sediment host rock is link: (1) to the understanding of their present state properties and 3-D repartition (from basin evolution, including sedimentary and diagenetic process); and (2) to the prediction of their future evolution during the next million years. For petroleum exploration, basin modelling aims at reconstructing the accumulation of hydrocarbons at basin scale, and at geological timescale, taking into account the effects of kinematics displacements, sedimentation, erosion, compaction, temperatures history, overpressures and fluids flows (water and hydrocarbons). Furthermore, explorationists wish to address overpressure reconstruction in order to estimate the risks of drilling. Clay sediments are of interest for petroleum exploration because source rocks and seal are generally composed of them. Nevertheless, in spite of their occurrence in nature their evolution at geological timescale is not well understood. And, most of the knowledge has been achieved by those working in the realms of soils mechanics and civil engineering until the present geological investigations for long term radioactive waste repositories. Application of this knowledge to clay sediment is considered to be valid within the first hundreds of meters at the top of the sedimentary pile, according to a repository depth. This paper is dedicated to the sedimentary rocks behaviour at geological timescale. This behaviour is characterised by: (1) the deposition of the sediment; (2) the loading path at geological timescale; (3) the constitutive law which includes the consolidation process and the rupture criteria; and (4) the parameters evolution related to consolidation. (author)

Influence of herbicide structure, clay acidity, and humic acid coating on acetanilide herbicide adsorption on homoionic clays.

Science.gov (United States)

Liu, Weiping; Gan, Jianying; Yates, Scott R

2002-07-03

Adsorption of chloroacetanilide herbicides on homoionic montmorillonite was studied by coupling batch equilibration and FT-IR analysis. Adsorption decreased in the order metolachlor > acetochlor > alachlor > propachlor on Ca(2+)- or Mg(2+)-saturated clays and in the order metolachlor > alachlor > acetachlor > propachlor on Al(3+)- or Fe(3+)-saturated clays. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in bonding. For the same herbicide, adsorption of alachlor, acetachlor, and metolachlor on clay followed the order Ca(2+) approximately Mg(2+) < Al(3+) < or = Fe(3+), which coincided with the increasing acidity of homoionic clays. Adsorption of propachlor, however, showed an opposite dependence, suggesting a different governing interaction. In clay and humic acid mixtures, herbicide adsorption was less than that expected from independent additive adsorption by the individual constituents, and the deviation was dependent on the clay-to-humic acid ratio, with the greatest deviation consistently occurring at a 60:40 clay-to-humic acid ratio.

Investigation of two-phase flow phenomena associated with corrosion in an SF/HLW repository in Opalinus Clay, Switzerland

International Nuclear Information System (INIS)

Senger, R.; Marschall, P.; Finsterle, S.

2008-01-01

Gas generation from corrosion of the waste canisters and gas accumulation in the backfilled emplacement tunnels is a key issue in the assessment of long-term radiological safety of the proposed repository for spent fuel and high-level waste (SF/HLW) sited in the Opalinus Clay formation of Northern Switzerland. Previous modeling studies indicated a significant pressure buildup in the backfilled emplacement tunnels for those sensitivity runs, where corrosion rates were high and the permeability of the Opalinus Clay was very low. As an extension to those studies, a refined process model of the canister corrosion phenomena has been developed, which accounts not only for the gas generation but also for the water consumption associated with the chemical reaction of corrosion of steel under anaerobic conditions. The simulations with the new process model indicate, that with increasing corrosion rates and decreasing host-rock permeability, pressure buildup increased, as expected. However, the simulations taking into account water consumption show that the pressure buildup is reduced compared to the simulation considering only gas generation. The pressure reduction is enhanced for lower permeability of the Opalinus Clay and for higher corrosion rates, which correspond to higher gas generations rates and higher water consumption rates. Moreover, the simulated two-phase flow patterns in the engineered barrier system (EBS) and surrounding Opalinus Clay show important differences at late time of the gas production phase as the generated gas continues to migrate outward into the surrounding host rock. For the case without water consumption, the water flow indicates overall downward flow due to a change in the overall density of the gas-fluid mixture from that based on the initially prescribed hydrostatic pressure gradient. For the case with water consumption, water flow converges toward the waste canister at a rate corresponding to the water consumption rate associated with the

On the Theory of Solitons of Fluid Pressure and Solute Density in Geologic Porous Media, with Applications to Shale, Clay and Sandstone

Science.gov (United States)

Caserta, A.; Kanivetsky, R.; Salusti, E.

2017-11-01

We here analyze a new model of transients of pore pressure p and solute density ρ in geologic porous media. This model is rooted in the nonlinear wave theory, its focus is on advection and effect of large pressure jumps on strain. It takes into account nonlinear and also time-dependent versions of the Hooke law about stress, rate and strain. The model solutions strictly relate p and ρ evolving under the effect of a strong external stress. As a result, the presence of quick and sharp transients in low permeability rocks is unveiled, i.e., the nonlinear "Burgers solitons". We, therefore, show that the actual transport process in porous rocks for large signals is not only the linear diffusion, but also a solitons presence could control the process. A test of a presence of solitons is applied to Pierre shale, Bearpaw shale, Boom clay and Oznam-Mugu silt and clay. An application about the presence of solitons for nuclear waste disposal and salt water intrusions is also discussed. Finally, in a kind of "theoretical experiment" we show that solitons could also be present in higher permeability rocks (Jordan and St. Peter sandstones), thus supporting the idea of a possible occurrence of osmosis also in sandstones.

Mineralogy and geotechnical characteristics of some pottery clay

Directory of Open Access Journals (Sweden)

Mujib Olamide ADEAGBO

2016-12-01

Full Text Available The physical properties of soils, which are tremendously influenced by the active clay minerals in soil, are of great importance in geotechnical engineering. This paper investigates the clay-sized particles of the Igbara-Odo pottery clay, and compares results obtained with available data on the bulk sample, to determine their correlation and underline the dependence of the geotechnical properties of the bulk clay material on the clay-sized particles. The bulk clay sample consists of 52% sand-size particles, 21% silt and 27% clay. Analysis of the clay-sized particles and the bulk materials shows: specific gravity of 2.07 and 2.66, liquid limit of 91.0% and 33.0%, plastic limit of 27.5% and 14.3%, plasticity index of 63.5% and 18.7% and a linear shrinkage of 7.9% and 5.4%, for both clay-sized particles and bulk clay respectively. The activity value of the clay material (0.64 suggests the presence of Kaolinite and Ilite; and these were confirmed with X-Ray diffraction on the bulk sample and clay-sized particles. X-Ray diffraction patterns shows distinctive peaks which highlight the dominance of Kaolinite (with 8 peaks in the pottery clay sample for both clay-sized particles and bulk material; while traces of other clay minerals like Illite and Halloysite and rock minerals like Mica, Feldspar and Chrysotile were also found. These results suggest that the clay possesses high viability in the manufacturing of ceramics, refractory bricks, paper, fertilizer and paint. The clay material can be used as a subgrade in road construction, since it possesses low swelling characteristics.

Xenon-129 NMR study of the microporous structure of clays and pillared clays

International Nuclear Information System (INIS)

Tsiao, C.; Carrado, K.A.

1990-01-01

129 Xe NMR studies have been carried out using xenon gas adsorbed in clays and pillared clays. Data from the measurements provide information on the pore structure of clays before and after pillaring. The results indicate that the effective pore diameter of montmorillonite increases, for example, from 5.4 Angstrom to 8.0 Angstrom after pillaring cheto-montmorillonite with aluminum polyoxohydroxy Keggin cations. The data are consistent with X-ray powder diffraction results, which show a corresponding increase in the interlamellar gallery height from 5.6 Angstrom to 8.4 Angstrom

Credit Booms and Busts in Emerging Markets: The Role of Bank Governance and Risk Management

OpenAIRE

Brown, Martin; Andries, Alin Marius

2014-01-01

This paper investigates to what extent risk management and corporate governance mitigate the involvement of banks in credit boom and bust cycles. Using a unique, hand-collected dataset on 156 banks from Central and Eastern Europe during 2005-2012, we assess whether banks with stronger risk management and corporate governance display more moderate credit growth in the pre-crisis credit boom as well as a smaller credit contraction and fewer credit losses in the crisis period. With respect to ba...

Low-Boom and Low-Drag Optimization of the Twin Engine Version of Silent Supersonic Business Jet

Science.gov (United States)

Sato, Koma; Kumano, Takayasu; Yonezawa, Masahito; Yamashita, Hiroshi; Jeong, Shinkyu; Obayashi, Shigeru

Multi-Objective Optimization has been applied to a design problem of the twin engine concept for Silent Supersonic Business Jet (SSBJ). This problem aims to find main wing, body, tail wing and engine nacelle configurations, which can minimize both sonic boom and drag in a supersonic cruising flight. The multi-objective genetic algorithm (MOGA) coupled with the Kriging model has been used to globally and effectively search for optimal design candidates in the multi-objective problem. The drag and the sonic boom have been evaluated by the computational fluid dynamics (CFD) simulation and the waveform parameter method. As a result, the present optimization has successfully obtained low-boom and low-drag design candidates, which are better than the baseline design by more than 40% regarding each performance. Moreover, the structure of design space has been visualized by the self-organizing map (SOM).

Study of a 30-M Boom For Solar Sail-Craft: Model Extendibility and Control Strategy

Science.gov (United States)

Keel, Leehyun

2005-01-01

Space travel propelled by solar sails is motivated by the fact that the momentum exchange that occurs when photons are reflected and/or absorbed by a large solar sail generates a small but constant acceleration. This acceleration can induce a constant thrust in very large sails that is sufficient to maintain a polar observing satellite in a constant position relative to the Sun or Earth. For long distance propulsion, square sails (with side length greater than 150 meters) can reach Jupiter in two years and Pluto in less than ten years. Converting such design concepts to real-world systems will require accurate analytical models and model parameters. This requires extensive structural dynamics tests. However, the low mass and high flexibility of large and light weight structures such as solar sails makes them unsuitable for ground testing. As a result, validating analytical models is an extremely difficult problem. On the other hand, a fundamental question can be asked. That is whether an analytical model that represents a small-scale version of a solar-sail boom can be extended to much larger versions of the same boom. To answer this question, we considered a long deployable boom that will be used to support the solar sails of the sail-craft. The length of fully deployed booms of the actual solar sail-craft will exceed 100 meters. However, the test-bed we used in our study is a 30 meter retractable boom at MSFC. We first develop analytical models based on Lagrange s equations and the standard Euler-Bernoulli beam. Then the response of the models will be compared with test data of the 30 meter boom at various deployed lengths. For this stage of study, our analysis was limited to experimental data obtained at 12ft and 18ft deployment lengths. The comparison results are positive but speculative. To observe properly validate the analytic model, experiments at longer deployment lengths, up to the full 30 meter, have been requested. We expect the study to answer the

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...

Pembuatan Alur Pelayaran dalam Rencana Pelabuhan Marina Pantai Boom, Banyuwangi

Directory of Open Access Journals (Sweden)

Muhammad Didi Darmawan

2017-01-01

Full Text Available Pantai Boom merupakan pantai yang ada di Kabupaten Banyuwangi. Pantai ini terletak di Kelurahan Kampung Mandar, Kecamatan Banyuwangi, Banyuwangi, Jawa Timur. Pantai tersebut rencananya akan dibangun pelabuhan marina. Pelabuhan harus dilengkapi dengan beberapa fasilitas untuk mendukung rencana tersebut seperti salah satunya adalah alur pelayaran. Untuk membuat alur pelayaran diperlukan penelitian mengenai pasang surut, topografi dasar laut, serta jenis kapal yang melintas untuk memastikan kapal yang berlayar aman dari kemungkinan kecelakaan. Penelitian ini menggunakan data hasil pemeruman, data pasang surut yang diperoleh dari pengamatan langsung, serta berbagai jenis kapal yacht. Hasil dari penelitian ini didapatkan bahwa rencana dermaga sebaiknya dibangun 60 meter menjorok ke arah laut dengan panjang dermaga 25 meter. Dalam keadaan air rendah terendah (LLWL, ketiga jenis kapal yang ditentukan dapat merapat ke rencana Dermaga Pelabuhan Marina Pantai Boom, Banyuwangi. Daerah yang tidak bisa dilewati pada saat LLWL, pada saat MSL daerah tersebut sudah dapat dilewati oleh ketiga jenis kapal tersebut. Pada keadaan muka air tinggi tertinggi (HHWL, Kapal Yacht Class 8 dan 6 dapat melewati sebagian perairan sungai Pantai Boom.         Waktu yang tidak tepat untuk melakukan pelayaran pada saat LLWL dari alur pelayaran yang telah dibuat yaitu antara pukul 04:00 – 06:00 WIB pada saat bulan November 2015-Februari 2016 dan pukul 16:00-18:00 pada saat bulan Juni-Agustus 2016. Sedangkan Waktu yang tepat untuk melakukan pelayaran pada saat HHWL yaitu antara pukul 20:00–23:00 WIB pada saat bulan Desember 2015- Maret 2016 dan pukul 8:00-11:00 pada saat bulan Juni-September 2016.

Characterization of clay minerals

International Nuclear Information System (INIS)

Diaz N, C.; Olguin, M.T.; Solache R, M.; Alarcon H, T.; Aguilar E, A.

2002-01-01

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

Determining redox properties of clay-rich sedimentary deposits in the context of performance assessment of radioactive waste repositories : Conceptual and practical aspects

NARCIS (Netherlands)

Behrends, T.; Bruggeman, Christophe

Redox reactions play a key factor controlling the mobility of redox sensitive radionuclides in clay-rich sediments which might serve as host formations for radioactive waste repositories. Assessing the redox speciation of radionuclides requires information about the redox conditions in the formation

Clays and Clay Minerals and their environmental application in Food Technology

Science.gov (United States)

del Hoyo Martínez, Carmen; Cuéllar Antequera, Jorge; Sánchez Escribano, Vicente; Solange Lozano García, Marina; Cutillas Díez, Raul

2013-04-01

The clay materials have led to numerous applications in the field of public health (del Hoyo, 2007; Volzone, 2007) having been demonstrated its effectiveness as adsorbents of all contaminants. Some biodegradable materials are used for for adsorption of chemical contaminants: lignins (Valderrabano et al., 2008) and also clays and clay minerals, whose colloidal properties, ease of generating structural changes, abundance in nature, and low cost make them very suitable for this kind of applications. Among the strategies used at present to preserve the quality of the water and this way to diminish the environmental risk that supposes the chemical pollution, stands out the use of adsorbents of under cost, already they are natural or modified, to immobilize these compounds and to avoid the pollution of the water with the consequent reduction of environmental and economic costs Thanks to the development of the science and the technology of the nourishment in the last 50 years, there have revealed itself several new substances that can fulfill beneficial functions in the food, and these substances, named food additives, are today within reach of all. The food additives recover a very important role in the complex nourishing supply. The additives fulfill several useful functions in the food, which often we give for sat. Nevertheless the widespread use of food additives in the food production also influences the public health. The food industries, which are very important for the economy, spill residues proved from its activity that they have to be controlled to evaluate the environmental impact and to offer the necessary information about the quantitative evaluation of the chemical risk of the use of food additives for the public health. We have studied the adsorption of several contaminants by natural or modified clays, searching their interaction mechanisms and the possible recycling of these materials for environmental purposes and prevention of the health. References

Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

Directory of Open Access Journals (Sweden)

Vernon Reynolds

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

Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

Science.gov (United States)

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

2015-01-01

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

Current-driven plasmonic boom instability in three-dimensional gated periodic ballistic nanostructures

Science.gov (United States)

Aizin, G. R.; Mikalopas, J.; Shur, M.

2016-05-01

An alternative approach of using a distributed transmission line analogy for solving transport equations for ballistic nanostructures is applied for solving the three-dimensional problem of electron transport in gated ballistic nanostructures with periodically changing width. The structures with varying width allow for modulation of the electron drift velocity while keeping the plasma velocity constant. We predict that in such structures biased by a constant current, a periodic modulation of the electron drift velocity due to the varying width results in the instability of the plasma waves if the electron drift velocity to plasma wave velocity ratio changes from below to above unity. The physics of such instability is similar to that of the sonic boom, but, in the periodically modulated structures, this analog of the sonic boom is repeated many times leading to a larger increment of the instability. The constant plasma velocity in the sections of different width leads to resonant excitation of the unstable plasma modes with varying bias current. This effect (that we refer to as the superplasmonic boom condition) results in a strong enhancement of the instability. The predicted instability involves the oscillating dipole charge carried by the plasma waves. The plasmons can be efficiently coupled to the terahertz electromagnetic radiation due to the periodic geometry of the gated structure. Our estimates show that the analyzed instability should enable powerful tunable terahertz electronic sources.

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

International Nuclear Information System (INIS)

Garcia, Claudia P.; Delpech, Marcia C.; Coutinho, Fernanda M.B.; Mello, Ivana L.

2009-01-01

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)

Seasonal Dynamics of Haptophytes and dsDNA Algal Viruses Suggest Complex Virus-Host Relationship.

Science.gov (United States)

Johannessen, Torill Vik; Larsen, Aud; Bratbak, Gunnar; Pagarete, António; Edvardsen, Bente; Egge, Elianne D; Sandaa, Ruth-Anne

2017-04-20

Viruses influence the ecology and diversity of phytoplankton in the ocean. Most studies of phytoplankton host-virus interactions have focused on bloom-forming species like Emiliania huxleyi or Phaeocystis spp. The role of viruses infecting phytoplankton that do not form conspicuous blooms have received less attention. Here we explore the dynamics of phytoplankton and algal viruses over several sequential seasons, with a focus on the ubiquitous and diverse phytoplankton division Haptophyta, and their double-stranded DNA viruses, potentially with the capacity to infect the haptophytes. Viral and phytoplankton abundance and diversity showed recurrent seasonal changes, mainly explained by hydrographic conditions. By 454 tag-sequencing we revealed 93 unique haptophyte operational taxonomic units (OTUs), with seasonal changes in abundance. Sixty-one unique viral OTUs, representing Megaviridae and Phycodnaviridae , showed only distant relationship with currently isolated algal viruses. Haptophyte and virus community composition and diversity varied substantially throughout the year, but in an uncoordinated manner. A minority of the viral OTUs were highly abundant at specific time-points, indicating a boom-bust relationship with their host. Most of the viral OTUs were very persistent, which may represent viruses that coexist with their hosts, or able to exploit several host species.

The Belgian demonstration programme for the disposal of high-level and long-lived radioactive waste

International Nuclear Information System (INIS)

Bernier, F.; Demarche, M.

2006-01-01

The EIG EURIDICE is responsible for performing large-scale tests, technical demonstrations and experiments so as to assess the feasibility of a final disposal of vitrified radioactive waste in deep clay layers. This programme is part of the Belgian Research and Development programme managed by ONDRAF/NIRAS. The research infrastructure includes the Underground Research Facilities HADES (URF HADES) in the Boom Clay geological formation and surface facilities. The achievements of the demonstration programme are the demonstration of the construction of shafts and galleries at industrial scale, the characterisation of the hydro-mechanical response of the host rock, and the 'OPHELIE mock-up' a large scale hydration test under thermal load of pre-fabricated bentonite blocks. The future works will consist mainly in the realisation of the 'PRACLAY experiments' including a large scale heater test. The results of this test will constitute an important input for the Safety and Feasibility Cases 1 (SFC-1, 2013) and 2 (SFC-2, 2020). (author)

Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

Energy Technology Data Exchange (ETDEWEB)

Leupin, O.X. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland); Bernier-Latmani, R.; Bagnoud, A. [Swiss Federal Office of Technology EPFL, Lausanne (Switzerland); Moors, H.; Leys, N.; Wouters, K. [Belgian Nuclear Research Centre SCK-CEN, Mol (Belgium); Stroes-Gascoyne, S. [University of Saskatchewan, Saskatoon (Canada)

2017-04-15

Microbiological studies related to the geological disposal of radioactive waste have been conducted at the Mont Terri rock laboratory in Opalinus Clay, a potential host rock for a deep geologic repository, since 2002. The metabolic potential of microorganisms and their response to excavation-induced effects have been investigated in undisturbed and disturbed claystone cores and in pore- (borehole) water. Results from nearly 15 years of research at the Mont Terri rock laboratory have shown that microorganisms can potentially affect the environment of a repository by influencing redox conditions, metal corrosion and gas production and consumption under favourable conditions. However, the activity of microorganisms in undisturbed Opalinus Clay is limited by the very low porosity, the low water activity, and the largely recalcitrant nature of organic matter in the claystone formation. The presence of microorganisms in numerous experiments at the Mont Terri rock laboratory has suggested that excavation activities and perturbation of the host rock combined with additional contamination during the installation of experiments in boreholes create favourable conditions for microbial activity by providing increased space, water and substrates. Thus effects resulting from microbial activity might be expected in the proximity of a geological repository i.e., in the excavation damaged zone, the engineered barriers, and first containments (the containers). (authors)

Fifteen years of microbiological investigation in Opalinus Clay at the Mont Terri rock laboratory (Switzerland)

International Nuclear Information System (INIS)

Leupin, O.X.; Bernier-Latmani, R.; Bagnoud, A.; Moors, H.; Leys, N.; Wouters, K.; Stroes-Gascoyne, S.

2017-01-01

Microbiological studies related to the geological disposal of radioactive waste have been conducted at the Mont Terri rock laboratory in Opalinus Clay, a potential host rock for a deep geologic repository, since 2002. The metabolic potential of microorganisms and their response to excavation-induced effects have been investigated in undisturbed and disturbed claystone cores and in pore- (borehole) water. Results from nearly 15 years of research at the Mont Terri rock laboratory have shown that microorganisms can potentially affect the environment of a repository by influencing redox conditions, metal corrosion and gas production and consumption under favourable conditions. However, the activity of microorganisms in undisturbed Opalinus Clay is limited by the very low porosity, the low water activity, and the largely recalcitrant nature of organic matter in the claystone formation. The presence of microorganisms in numerous experiments at the Mont Terri rock laboratory has suggested that excavation activities and perturbation of the host rock combined with additional contamination during the installation of experiments in boreholes create favourable conditions for microbial activity by providing increased space, water and substrates. Thus effects resulting from microbial activity might be expected in the proximity of a geological repository i.e., in the excavation damaged zone, the engineered barriers, and first containments (the containers). (authors)

Simulation and controller design for an agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian; Miao, Yubin

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the operation process. Thus we can

Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

Science.gov (United States)

Ugochukwu, Uzochukwu C; Fialips, Claire I

2017-07-01

Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prime Borrowers and Financial Innovation in the Housing Boom and Bust

DEFF Research Database (Denmark)

Bäckman, Claes; Lutz, Chandler

for better consumption smoothing, even absent any shift in credit supply. In support of the model, we find that the introduction of interest-only mortgages was followed by a large increase in the number of buyers, even as credit quality remained constant. On the aggregate level the results indicate...... that interest-only mortgages amplified the boom-bust pattern in housing: house prices increased an additional 35 percent during the boom due to IO loans, and subsequently reverse during the bust. These effects, which cannot be explained by changes in lending standards or shifts in credit supply, are magnified...... in local housing markets with higher ex-ante house price expectations. Together, the findings document the consequences of introducing IO loans on the micro- and macro level, and illustrates how new mortgage products can have large impacts even in the absence of a shift in credit supply...

From clay bricks to deep underground storage

International Nuclear Information System (INIS)

2012-05-01

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

Microstructure and Thermal Properties of Polypropylene/Clay Nanocomposites with TiCl4/MgCl2/Clay Compound Catalyst

Directory of Open Access Journals (Sweden)

Limei Wang

2015-01-01

Full Text Available Polypropylene (PP/clay nanocomposites were synthesized by in situ intercalative polymerization with TiCl4/MgCl2/clay compound catalyst. Microstructure and thermal properties of PP/clay nanocomposites were studied in detail. Fourier transform infrared (FTIR spectra indicated that PP/clay nanocomposites were successfully prepared. Both wide-angle X-ray diffraction (XRD and transmission electron microscopy (TEM examination proved that clay layers are homogeneously distributed in PP matrix. XRD patterns also showed that the α phase was the dominate crystal phase of PP in the nanocomposites. Thermogravimetric analysis (TGA examinations confirmed that thermal stability of PP/clay nanocomposites was markedly superior to pure PP. Differential scanning calorimetry (DSC scans showed that the melt temperature and the crystallinity of nanocomposites were slightly lower than those of pure PP due to crystals imperfections.

Changing Fortunes: How China’s Boom Caused the Financial Crisis

NARCIS (Netherlands)

H. Mees (Heleen)

2012-01-01

textabstractThis dissertation includes five academic papers that – one way or the other – all relate to China. The first paper delivers proof for the central thesis of this thesis, which is that China’s boom caused the 2008 financial crisis and ensuing recession. As much as I hoped from the outset

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

Energy Technology Data Exchange (ETDEWEB)

Miller, Andrew; Kruichiak, Jessica; Tellez, Hernesto; Wang, Yifeng [Sandia National Laboratories, Albuquerque, NM 87185 (United States)

2012-07-01

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

Preparation and characterization of nano gold supported over montmorillonite clays

International Nuclear Information System (INIS)

Suraja, P.V.; Binitha, N.N.; Yaakob, Z.; Silija, P.P.

2009-01-01

Full text: The use of montmorillonite clays as a matrix, or as a host, for obtaining intercalated/supported metal particles has potential applications in catalysis and other areas. The gold nanoparticles were obtained from the most common anionic gold precursor HAuCl 4 ·3H 2 O by deposition-precipitation (DP) methods. However, it is difficult to prepare nano scale gold catalysts supported on silica surfaces with lower isoelectric point (IEP). Homogeneous precipitation method using urea also fails on silica surfaces. Reasons for the inefficiency of these methods are the negative charge of the metal precursor as well as the support surface and the high pH required for depositing gold nanoparticles. In the present work, we use glucose as the reductant in the presence of stabilizer for preparation of nano gold supported on montmorillonite clay. Here there is no need of increasing the pH of the solution to reduce the Au 3+ ions. The prepared systems are characterized using various techniques such as using X-ray fluorescence (XRF), UV-Vis Diffuse reflectance spectra (DRS) and Fourier Transform infra red spectra (FTIR) to prove the efficiency of the present method. (author)

Preparation and Characterization of Nano Gold Supported over Montmorillonite Clays

Energy Technology Data Exchange (ETDEWEB)

Suraja, P V; Binitha, N N; Yaakob, Z; Silija, P P, E-mail: binithann@yahoo.co.in [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, National University of Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

2011-02-15

The use of montmorillonite clays as a matrix, or as a host, for obtaining intercalated/supported metal particles has potential applications in catalysis and other areas. The gold nanoparticles were obtained from the most common anionic gold precursor HAuCl4{center_dot}3H2O by deposition-precipitation (DP) methods. However, it is difficult to prepare nanoscale gold catalysts supported on silica surfaces with lower isoelectric point (IEP). Homogeneous precipitation method using urea also fails on silica surfaces. Reasons for the inefficiency of these methods are the negative charge of the metal precursor as well as the support surface and the high pH required for depositing gold nanoparticles. In the present work, we use glucose as the reductant in the presence of stabilizer for preparation of nano gold supported on montmorillonite clay. There is no need of increasing the pH of the solution to reduce the Au3+ ions. The prepared systems are characterized using various techniques such as using X-ray fluorescence (XRF), UV-VIS Diffuse reflectance spectra (DRS) and Fourier Transform infra red spectra (FTIR) to prove the efficiency of the present method.

An investigation of the characteristics of humic acid and of its effects on the chemistry of the near field of a radioactive waste repository

International Nuclear Information System (INIS)

Bates, C.I.; Bayliss, S.; Gardiner, M.P.; Hobley, J.; Smith, A.J.; Williams, S.J.

1992-07-01

The work described in this report attempts to assess the possible effects of humic substances in the near field of a radioactive waste repository. Two samples of humic acid were studied by analytical ultracentrifugation. It was found to be an advantage to reduce sample polydispersity before carrying out molecular weight determinations. Ultrafiltration experiments showed that calcium concentrations of greater than 10 -3 M were sufficient to cause precipitation of humic acid. Boom clay extracts in sodium hydroxide solution were able to maintain high concentrations of americium in the aqueous phase. Extracts of Boom clay in cement-equilibrated water showed less ability to increase americium concentrations. The sorption of americium on BFS/OPC was studied. Distribution ratios of 600 ml g -1 in the absence of humic acid and 500 ml g -1 in its presence were obtained. Size distribution studies on americium showed that humic acid had little effect on the concentration of the radioelement in solutions passed through filters with up to 2 μm pore size. However, size distribution studies on plutonium revealed that more plutonium was associated with each filtered fraction in the experiments which contained Boom clay extract than in those which used cement-equilibrated water. Measurements of the sorption of neptunium on cements showed that this radioelement was strongly sorbed onto both 9:1 BFS/OPC and the Nirex reference backfill. The presence of humic acid extracted from Boom clay did not cause any discernible decrease in the sorption of this radioelement on cement. Thermodynamic calculations, using a simple model, illustrate the important role which calcium could play in controlling the concentrations of actinide humates in the near-field porewater. (author)

Feasibility of using overburden clays for sealing purposes and laboratory testing of the clays

Energy Technology Data Exchange (ETDEWEB)

Mann, J. (Vyzkumny Ustav pro Hnede Uhli, Most (Czechoslovakia))

1992-03-01

Studies properties of overburden clay from North Bohemian surface coal mines for use as sealants of industrial and household waste that will be dumped at Czechoslovak surface mine sites. Basic requirements of sealing layers are optimum compressibility and impermeability by suitable compacting. Laboratory soil mechanical tests of different clay samples were carried out using the Proctor standard tests (PCS) and the Norwegian Geonor A/S - m 45 instrument. Laboratory tests were used to select the best available clay types with optimum density and moisture content. Experimental results of laboratory tests are provided.

Sorption of radionuclides by tertiary clays

International Nuclear Information System (INIS)

Wagner, J.F.; Czurda, K.A.

1990-01-01

The sorption capacity of different clay types for some metals (Co, Cs, Sr and Zn), occurring as common radionuclides in radioactive waste deposits, had been analysed by a static (batch technique) and a dynamic method (percolation tests, in which the driving force is a hydraulic gradient). Sorption capacity generally increased with an increasing pH of solution. A decrease of sorption capacity had been observed in the order Zn > Cs ≥ Co > Sr for the batch and Cs > Zn > Sr > Co for the percolation tests. Clay marls showed a distinctly higher sorption respectively retention capacity as pure clays. Sorption capacity depends on solution parameters like type and concentration of radionuclide, pH, salt concentration, etc., and on rock parameters like mineral content (e.g. swelling clay minerals and carbonates), organic material, rock pH, micro fabric, etc. A third parameter of great influence is the contact time between clay and solution. The adsorption isotherms reflect two different adsorption mechanisms: a very rapid adsorption (a few minutes) on the external surfaces of clay minerals and a slow adsorption process (weeks and longer), due to the diffusion of metal ions into the interlayer space of clay minerals. 12 refs., 9 figs., 1 tab

The connectivity of pore space in mudstones: insights from high-pressure Wood's metal injection, BIB-SEM imaging, and mercury intrusion porosimetry

NARCIS (Netherlands)

Klaver, J.; Hemes, S.; Houben, M.; Desbois, G.; Radi, Z.; Urai, J.L.

2015-01-01

Study of the pore space in mudstones by mercury intrusion porosimetry is a common but indirect technique and it is not clear which part of the pore space is actually filled with mercury. We studied samples from the Opalinus Clay, Boom Clay, Haynesville Shale, and Bossier Shale Formations using

Organophilization and characterization of commercial bentonite clays

International Nuclear Information System (INIS)

Cunha, B.B. da; Lima, J.C.C.; Alves, A.M.; Araujo, E.M.; Melo, T.J.A. de

2012-01-01

Bentonite clay is a plastic changes resulting from volcanic ash, consisting mostly of montmorillonite. The state of Paraiba is a major source of bentonite clay from Brazil, where the main oil fields are located in Boa Vista and represents the largest national production of raw and beneficiated bentonite. Aimed at the commercial value of this type of clay and its high applicability in the polls, this article aims to make a comparison between two kinds of clay, a national (Brasgel) and other imported (Cloisite) from organophilization of two commercial bentonite, ionic surfactant with Praepagem WB, and characterize them by XRD, FTIR and TG / DTG. We observe that despite getting inferior properties, the clay presents national values very similar to those presented by imported clay. (author)

Performance assessment of the disposal of vitrified high-level waste in a clay layer

International Nuclear Information System (INIS)

Mallants, Dirk; Marivoet, Jan; Sillen, Xavier

2001-01-01

Deep disposal is considered a safe solution to the management of high-level radioactive waste. The safety is usually demonstrated by means of a performance assessment. This paper discusses the methodological aspects and some of the results obtained for the performance assessment of the disposal of vitrified high-level waste in a clay layer in Belgium. The calculations consider radionuclide migration through the following multi-barrier components, all of which contribute to the overall safety: (1) engineered barriers and the host clay layer, (2) overlying aquifer, and (3) biosphere. The interfaces between aquifers and biosphere are limited to the well and river pathway. Results of the performance assessment calculations are given in terms of the time evolution of the dose rates of the most important fission and activation products and actinides. The role of the glass matrix in the overall performance of the repository is also discussed

Thermal Behaviour of clay formations

International Nuclear Information System (INIS)

Tassoni, E.

1985-01-01

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 . 0 C -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

Silt-clay aggregates on Mars

International Nuclear Information System (INIS)

Greeley, R.

1979-01-01

Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates together. Various laboratory experiments conducted since the 19th century, and as reported here for simulated Martian conditions, show that both the magnitude and sign of electrical charges on windblown particles are functions of particle velocity, shape and composition, atmospheric pressure, atmospheric composition, and other factors. Electrical charges have been measured for saltating particles in the wind tunnel and in the field, on the surfaces of sand dunes, and within dust clouds on earth. Similar, and perhaps even greater, charges are proposed to occur on Mars, which could form aggregates of silt and clay size particles. Electrification is proposed to occur within Martian dust clouds, generating silt-clay aggregates which would settle to the surface where they may be deposited in the form of sandlike structures. By analog, silt-clay dunes are known in many parts of the earth where silt-clay aggregated were transported by saltation and deposited as 'sand.' In these structures the binding forces were later destroyed, and the particles reassumed the physical properties of silt and clay, but the sandlike bedding structure within the 'dunes' was preserved. The bedding observed in drifts at the Viking landing site is suggested to result from a similar process involving silt-clay aggregates on Mars

Backfilling and sealing of repositories and access shafts and galleries in clay, granite and salt formations

International Nuclear Information System (INIS)

Lake, L.M.; Davies, I.L.; Gera, F.; Jorda, M.; McEwen, T.; Neerdael, B.; Schmidt, M.W.

1985-01-01

The paper summarizes the work carried out under ten Commission contracts in the field of backfilling and sealing radioactive waste repositories. It covers theoretical, laboratory and field trials and experiments involving three potential host types, namely clay, salt and hard rock. It concludes that maximum opportunity should be taken over the next 15 to 25 years with a view to obtaining first hand experience in real ground with real wastes

What Makes a Natural Clay Antibacterial?

Science.gov (United States)

Williams, Lynda B.; Metge, David W.; Eberl, Dennis D.; Harvey, Ronald W.; Turner, Amanda G.; Prapaipong, Panjai; Poret-Peterson, Amisha T.

2011-01-01

Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial clays contain nanoscale (clay minerals in the bactericidal process is to buffer the aqueous pH and oxidation state to conditions that promote Fe2+ solubility. Chemical analyses of E. coli killed by aqueous leachates of an antibacterial clay show that intracellular concentrations of Fe and P are elevated relative to controls. Phosphorus uptake by the cells supports a regulatory role of polyphosphate or phospholipids in controlling Fe2+. Fenton reaction products can degrade critical cell components, but we deduce that extracellular processes do not cause cell death. Rather, Fe2+ overwhelms outer membrane regulatory proteins and is oxidized when it enters the cell, precipitating Fe3+ and producing lethal hydroxyl radicals. PMID:21413758

Financial services in England in the late XVII century and first equity market boom (1691–1693

Directory of Open Access Journals (Sweden)

S.Z. Moshenskyi

2016-09-01

Full Text Available The article shows the formation of the British financial services industry in the 1690's and the reasons of the first joint-stock companies’ boom of 1691–1693's. The author describes the course of events of this boom, and data on the volume of transactions in shares. The reasons of the joint-stock boom end are associated with very low capitalization of most of the new companies. The consequence of rapid economic growth in England in the late XVII century was the appearance and rapid development of financial services. Financial intermediaries appeared first and their services, in particular the services of insurance companies, were in demand. The rapid increase in the number of insurance companies has become prerequisite for becoming financial capitalism that led to the emergence of other intermediaries which provided financial services. Among them there were the so-called "notaries" that offered a full range of services related to land transactions and "bankers, jewelers," that woke the first private bankers. Thus, in the early 1690's London had a favorable environment for the rapid growth of the financial market, which was the main precondition for expanding market shares and led to the joint-stock boom.

Iodide uptake by negatively charged clay interlayers?

International Nuclear Information System (INIS)

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

2015-01-01

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. - 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

Stools - pale or clay-colored

Science.gov (United States)

... gov/ency/article/003129.htm Stools - pale or clay-colored To use the sharing features on this page, please enable JavaScript. Stools that are pale, clay, or putty-colored may be due to problems ...

Mars, clays and the origins of life

Science.gov (United States)

Hartman, Hyman

1989-01-01

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

Preparation of organophilic clays and polypropylene nano composites

International Nuclear Information System (INIS)

Lima, Martha Fogliato S.; Nascimento, Vinicius G. do; Lenz, Denise M.; Schenato, Flavia

2011-01-01

Polypropylene/montmorillonite nano composites were prepared by the melt intercalation technique. The clay was organically modified with different quaternary ammonium salts to obtain the organo clay. The modified clays with the quaternary ammonium salts were introduced in a polypropylene matrix with 3 wt. % of clay. The interlayer distance (d001) of the clay particles were obtained by X- ray diffraction and the thermal stability of the systems were investigated by thermogravimetry. The organo clay presence in the polymer matrix increased the degradation temperature in relation to the pure polymer. (author)

Cellulose-containing Waste and Bituminized Salts

International Nuclear Information System (INIS)

Valcke, E.

2005-01-01

In Belgium, Medium-Level radioactive Waste (MLW) would be eventually disposed off in an underground repository in a geological formation such as the Boom Clay, which is studied as a reference host rock formation. MLW contains large quantities of non-radioactive chemicals that are released upon contact with pore water. It could be the case, for instance, for plutonium bearing cellulosic waste - such as paper tissues used to clean alpha glove boxes - issued from nuclear fuel fabrication (Belgonucleaire). At high pH, as in a disposal gallery backfilled with cement, the chemical degradation of cellulose will generate water-soluble products that may form strong complexes with actinides such as Am, Pu, Np, and U. This could lower the sorption of these elements onto the clay minerals, and hence increase their migration through the clay barrier. Another chemical perturbation could occur from the 3000 m 3 of so-called Eurobitum bituminised MLW, with precipitation sludges from the chemical treatment of spent nuclear fuel, and containing about 750 tons of NaNO 3 . The presence of NaNO 3 in this waste will give rise to several processes susceptible to affect the safety of the disposal system. Amongst others, it is necessary to verify that the swelling pressure of bitumen on the gallery wall and the osmotic pressure within the near-field are not too high to induce a fissuration of the host rock, leading to the formation of preferential migration pathways. The major objective of our work is to obtain a broad understanding of the different processes induced by the release of non-radioactive chemicals in the clay formation, to assess the chemical compatibility of different MLW forms with the clay

Being young in a boom town

Energy Technology Data Exchange (ETDEWEB)

O' Connor, Christopher

2011-08-15

Fort McMurray is a booming town, having grown from small town to big city in a short time. A study was conducted to determine how this change affected young people. Results show they felt the changing environment required them to adapt all the time, which was a challenge but also a source of opportunities. Fort McMurray, with a labour shortage, afforded young people a lot of well-paid, flexible part time jobs during high school. These jobs were important to fund their post-secondary education. Although most of the young people saw themselves living elsewhere in 10 years, they could possibly stay if local challenges in the city were addressed.

Hydrogen isotope ratios of clay minerals constituting clay veins found in granitic rocks in Hiroshima Prefecture

International Nuclear Information System (INIS)

Kitagawa, Ryuji; Kakitani, Satoru; Kuroda, Yoshimatsu; Matsuo, Sadao; Suzuoki, Tetsuro.

1980-01-01

The deuterium content of the constitutional and interlayer water extracted from the clay minerals (illite, montmorillonite, interstratified illite-montmorillonite mineral, kaolinite, halloysite) constituting the clay veins found in the granitic rocks in Hiroshima Prefecture was measured. The clay minerals were heated at 270 deg C to extract the interlayer water, then heated to 1,400 or 1,500 deg C to extract the constitutional water. The deuterium content of the local surface water collected from sampling points was measured. In the clay veins formed along perpendicular joints, the constituent clay minerals change from lower to upper part: illite → montmorillonite → kaolinite → halloysite. The deuterium content values of the constitutional water for illite and montmorillonite were estimated to be -67 to -69% and -86 to -89%, respectively. The deuterium content values of the constitutional water for halloysite range from -68 to -80% and for kaolinite from -63 to -67%. (J.P.N.)

Physical Matrix Characterisation: Studies of Crystalline Rocks and Consolidated Clays by PMMA Method and Electron Microscopy as Support of Diffusion Analyses

Energy Technology Data Exchange (ETDEWEB)

Siitari-Kauppi, M.; Leskinen, A.; Kelokaski, A.; Togneri, L.; Alonso, U.; Missana, T.; Garcia-Gutierrez, M.; Patelli, A.

2007-07-01

Crystalline rock and consolidated clay are both considered adequate host rocks for a high-level radioactive waste deep geological repository (HLWR). Over the extended periods of HLWR operation, long-lived radionuclides (RN) may be released from the fuel and migrate to the geo/biosphere. To predict the fate of contaminants and to assess the safety of the host rock, it is very important to determine transport parameters, as diffusion coefficients, and to relate them to the physical properties of the barriers, as connected porosity. In heterogeneous materials, it is also a major task to describe the transport at the mineral scale evaluating diffusion coefficients and mineral-specific porosities on single minerals. The main objective of this study was to determine within granite and consolidated clay, the connective porosity and mineral-specific porosities by poly-methylmethacrylate (PMMA) autoradiography method. Scanning electron microscopy and energy-dispersive X-ray analyses (FESEM/EDS) were performed in order to study the pore apertures of porous regions in greater detail and to identify the corresponding minerals. By the novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS) apparent diffusion coefficients were determined at mineral scale. Finally, the porosity results were used to evaluate the effective diffusion coefficients and retention parameters of single minerals in different granite samples and consolidated clays. (Author) 42 refs.

Monitoring water content in Opalinus Clay within the FE-Experiment: Test application of dielectric water content sensors

Science.gov (United States)

Sakaki, T.; Vogt, T.; Komatsu, M.; Müller, H. R.

2013-12-01

The spatiotemporal variation of water content in the near field rock around repository tunnels for radioactive waste in clay formations is one of the essential quantities to be monitored for safety assessment in many waste disposal programs. Reliable measurements of water content are important not only for the understanding and prediction of coupled hydraulic-mechanic processes that occur during tunnel construction and ventilation phase, but also for the understanding of coupled thermal-hydraulic-mechanical (THM) processes that take place in the host rock during the post closure phase of a repository tunnel for spent fuel and high level radioactive waste (SF/HLW). The host rock of the Swiss disposal concept for SF/HLW is the Opalinus Clay formation (age of approx. 175 Million years). To better understand the THM effects in a full-scale heater-engineered barrier-rock system in Opalinus Clay, a full-scale heater test, namely the Full-Scale Emplacement (FE) experiment, was initiated in 2010 at the Mont Terri underground rock laboratory in north-western Switzerland. The experiment is designed to simulate the THM evolution of a SF/HLW repository tunnel based on the Swiss disposal concept in a realistic manner during the construction, emplacement, backfilling, and post-closure phases. The entire experiment implementation (in a 50 m long gallery with approx. 3 m diameter) as well as the post-closure THM evolution will be monitored using a network of several hundred sensors. The sensors will be distributed in the host rock, the tunnel lining, the engineered barrier, which consists of bentonite pellets and blocks, and on the heaters. The excavation is completed and the tunnel is currently being ventilated. Measuring water content in partially saturated clay-rich high-salinity rock with a deformable grain skeleton is challenging. Therefore, we use the ventilation phase (before backfilling and heating) to examine the applicability of commercial water content sensors and to

The HADES demonstration and pilot project on radioactive waste disposal in a clay formation

International Nuclear Information System (INIS)

Bonne, A.; Beckers, H.; Beaufays, R.; Buyens, M.; Coursier, J.; Bruyn, D. de; Fonteyne, A.; Genicot, J.; Lamy, D.; Meynendonckx, P.; Monsecour, M.; Neerdael, B.; Noynaert, L.; Voet, M.; Volekaert, G.

1992-01-01

The overall objective of the HADES programme is the evaluation of the technical feasibility and safety of the disposal of radwaste in a deep clay formation. The pilot phase is aimed at demonstrating the system behaviour for those components of the system and those operations and issues which can be demonstrated directly. The time period considered covers a first phase of the development programme of the pilot project which includes: -The construction of a concrete lined tests drift of about 30 m length with a useful inner diameter of 3.5 m. In the lining, a number of openings or ports are foreseen for emplacing the various tests and sensors for the general auscultation in the host rock; - Mine-by test for the investigation of the response of the surrounding clay on the excavating; - CERBERUS test, a combined heating-irradiation test aiming at evaluating by simulation (electrical heaters and Co-60 radiation source) the impact of a HLW canister on its immediate near field; - Design of a gallery heating test for the demonstration by simulation of the behaviour of a concrete lined gallery structure and of the surrounding clay mass in a temperature field (TEMPPRES code for temperature and pressure evolution simulation). 21 refs

Baby boom generation at the retirement onset

Directory of Open Access Journals (Sweden)

Stojilković Jelena

2010-01-01

Full Text Available Sudden increase in the number of live births after the Second World War due to an increase in fertility rates has led to the formation of cohorts with specific characteristics or baby boom generation. This generation is unique in the history of the demographic phenomenon that has affected and affects the functioning of many segments of society. The aim of this paper is to assess structure of baby boomers who are few years away from retirement, using demographic data. Impact of baby boomer age structure of current and future retirees is described with a graphical display of current and projected age pyramid of baby boomers. Demographic pattern that women live longer than men is evident in the projected pyramid. In addition, the number of baby boomers will lead to a "younger" old population. The imbalance in the number of men and women pensioners, as well as older cohorts of women and female baby boomers was analyzed. As a result, an increasing trend of women's age pensioners who are members of the baby boom generation was clearly observed, which is opposite to the older cohort of women who often were family pensioners. Different circumstances and conditions in which female boomers lived and worked will form a new "pension model" because they will gain their benefits as well as men, for the first time in significant number, unlike their mothers, which gained the right to retire after they become widows. Number of women age pensioners is getting greater comparing to men, as the result of changes in the economic activities of women in the last half of the 20th century. When baby boomers retire and exit the working population, this will create a vacuum, because the numerically smaller generations will enter working population, while the sudden and very shortly, the number of population older than 60 or 65 will increase, most of them will likely to acquire the right to a pension. It is undeniable that baby boomers had impact on demographic structure

Pedological ~cterization, Clay Mine:at~ and .~cation of,

African Journals Online (AJOL)

namely, very deep, well drained, dark reddish brown to dark brown, sandy clay loams and sandy clays on the steep convex slopes; very deep, well drained, dark brown to dark red, sandy clay loams and; sandy clays on the linear slopes; and very ...

Preparation and characterization of bentonite organo clay

International Nuclear Information System (INIS)

Bertagnolli, C.; Almeida Neto, A.F.; Silva, M.G.C.

2009-01-01

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

Treatment for cracked and permeable Houston clay

International Nuclear Information System (INIS)

Vipulanandan, C.; Leung, M.

1991-01-01

In this study, the treatability of a field clay (obtained from Houston, Texas) and a clay-sand mixture to reduce their hydraulic conductivity was evaluated. Remolded field clay and clay-sand mixture with and without methanol contamination were treated to reduce their hydraulic conductivity by permeating very dilute grout solutions. The concentration of sodium silicate in the grout solution was 8%, while the solid content in the cement grout was 0.3%. The hydraulic conductivity of permeable Houston clay (hydraulic conductivity >10 -5 cm/sec) could be reduced to less than 10 -7 cm/sec (U.S. EPA limit for soil barriers) by permeating with a selected combination of grout solutions

Characterization of clay used for red ceramic fabrication

International Nuclear Information System (INIS)

Pereira, P.S.; Morais, A.S.C.; Caldas, T.C.C.; Monteiro, S.N.; Vieira, C.M.F.

2011-01-01

The objective of this work is to characterize a clay used in the red ceramics fabrication, from Campos dos Goytacazes north of the State of Rio de Janeiro. The clay was submitted for physical, chemical and mineralogical tests. The results showed that the clay has a high content of clay minerals with kaolinitic predominance, high loss on ignition and low flux oxides. It is recommended that this clay is mixed with non-plastic materials. (author)

Encapsulation of Clay Platelets inside Latex Particles

NARCIS (Netherlands)

Voorn, D.J.; Ming, W.; Herk, van A.M.; Fernando, R.H.; Sung, Li-Piin

2009-01-01

We present our recent attempts in encapsulating clay platelets inside latex particles by emulsion polymerization. Face modification of clay platelets by cationic exchange has been shown to be insufficient for clay encapsulation, leading to armored latex particles. Successful encapsulation of

Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

Science.gov (United States)

Moran, Anthony R.; Hettiarachchi, Hiroshan

2011-01-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling. PMID:21845150

Geotechnical characterization of mined clay from Appalachian Ohio: challenges and implications for the clay mining industry.

Science.gov (United States)

Moran, Anthony R; Hettiarachchi, Hiroshan

2011-07-01

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

Directory of Open Access Journals (Sweden)

Anthony R. Moran

2011-06-01

Full Text Available Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

Observations on burrowing rates and comments on host specificity in the endangered mussel Lampsilis higginsi

Science.gov (United States)

Sylvester, J.R.; Holland, L.E.; Kamer, T.K.

1984-01-01

In preliminary laboratory studies, the endangered mussel Lampsilis higginsi was unable to burrow into rocky substrates, but did burrow into substrates comprised of silt, clay, sand, and/or pebble-gravel. Burrowing times were shortest in silt and longest in pebble-gravel. As judged by longevity of glochidial infection, walleye (Stizostedion vitreum) and largemouth bass (Micropterus salmoides) may be suitable hosts for the parasitic stage. When glochidia were placed in water without host fish, half had died after 48 hours, and all had died after 72 hours. (DBO).

Sorption of Pu onto some kinds of clay

International Nuclear Information System (INIS)

Jia Haihong; Si Gaohua; Liu Wei; Yu Jing

2010-01-01

There are rich clay mines holding in one area, so it's necessary to know about these clays' sorption capacity to Pu, for building radioactive waste repository in the area. Distribution coefficients of Pu onto different clays were acquired in static method, with the result about 104. The size of clay is different, but the result of Kds is near. In addition, it's estimated how far Pu moves in the most rapid speed in the clay based on these Kids', disregarding the influence of Pu-colloid. In a word, as a kind of backfilling material clays in the area can effectively prevent Pu from moving to environment, and when designing the backfilling layer, it's not necessary to catch clays through NO.200 sieve, if only considering the influence of Kd. (authors)

Rheological characterization of nanocomposites Nylon 6/bentonite clay

International Nuclear Information System (INIS)

Silva, T.R.G.; Fernandes, P.C.; Oliveira, S.V.; Araujo, E.M.; Melo, T.J.A.

2010-01-01

Polymer nanocomposites are a class of materials that have been widely used in various applications. Among them, has been emphasizing the preparation of polymer films with barrier properties for applications in polymer membranes. In this work, nanocomposites of nylon 6/bentonite clay were obtained from a Homogenizer, in the ratios of 1, 3 and 5 wt% clay. The Brasgel PA bentonite clay was treated organically with Praepagen HY salt, to make it organophilic. By X-ray diffraction (XRD), it was showed that the efficiency of the incorporation of salt in the clay. The rheological curves showed that for the AST clay the torque did not change when compared with the pure nylon 6, while for the clay ACT, the torque increased gradually with the percentage of clay. (author)

Ageing of EUROBITUM bituminised radioactive waste

International Nuclear Information System (INIS)

Valcke, E.

2009-01-01

Since the end of the 1970s, about 3000 m 3 of Eurobitum bituminised radioactive waste has been produced by the EUROCHEMIC/BELGOPROCESS reprocessing facility for the incorporation of precipitation sludges and evaporator concentrates originating from the chemical reprocessing of spent nuclear fuel. Eurobitum is a homogeneous mixture of 60 weigh percent of bitumen and 40 weight percent of waste, of which NaNO3 is the most important component (60-75 weight percent ). The preferred option of ONDRAF/NIRAS for the long-term management of Eurobitum is final disposal in a geologically stable underground clay formation. The Boom Clay is presently being studied as a reference host formation. Due to a combination of favourable properties, the Boom Clay will delay and spread in time the migration of the radionuclides, allowing the majority to decay before reaching the aquifers. Owing to the importance of the clay host formation in the overall repository safety, the processes induced by the emplacement of Eurobitum should not negatively affect the long-term safety functions of this barrier. Basically, two types of disturbances can be distinguished: (1) a mechanical disturbance, caused by the build-up of a pressure in and around the waste, and (2) a chemical disturbance by the release of large amounts of NaNO3 and of water-soluble, organic, potentially complexing molecules due to radiolytic and chemical degradation of the bitumen. The extent of some of these processes will be affected by the continuous evolution of the rheological properties of the bitumen, especially in the presence of oxygen and/or radiation. This ageing results in a harder bitumen, which tends to loose its binding capacity and which becomes increasingly brittle. Fissures and changes in membrane properties of bitumen in terms of oxygen and water diffusion are expected to favour the penetration of oxygen, thus amplifying the ageing deeper inside the product, and the infiltration of pore water, thus possibly

Polymer-clay nanocomposites obtained by solution polymerization ...

Indian Academy of Sciences (India)

Clay minerals can be found all over the world.1 Clay minerals have ... salts or covalent bonding with silanes at the OH edges of the clay. ..... Marras S I, Tsimpliaraki A, Zuburtikudis I and ... Mansoori Y, Roojaei K, Zamanloo M R and Imanzadeh.

Did the Aid Boom Pacify Sub-Saharan Africa?

OpenAIRE

Azam, Jean-Paul; Thelen, Véronique

2017-01-01

The incidence of civil war in Sub-Saharan Africa since the turn of the century is less than half of what it was on average in the last quarter of the 20th century. This paper shows that the aid boom triggered by 9/11 played a key role in achieving purposefully this result using panel data for 46 African countries over four decades. It applies a nearidentification approach to test the aid-conflict tradeoff, taking due account of asymmetric information between the donors and the econometrician....

Clays in natural and engineered barriers for radioactive waste confinement - 5. International meeting. Book of abstracts

International Nuclear Information System (INIS)

2012-10-01

The purpose of this fifth international meeting is to bring again together specialists in the different disciplines related to clays and clay minerals, with scientists from organizations engaged in disposal of radioactive waste in order to evaluate the progress of the research conducted in that field. Multidisciplinary approaches including geology, mineralogy, geochemistry, rheology, physics and chemistry of clay minerals and assemblages are required in order to provide a detailed characterization of the geological host formations considered for the disposal of radioactive waste and to assess the behaviour of engineered and natural barriers when submitted to various types of perturbations induced by such facilities. The evaluation of the performances of the natural barrier as well as of the impact of repository-induced disturbances upon the confinement properties of clay-rich geological formations constitute major objectives for the experimental programs being and/or to be conducted in underground research laboratories, for interpreting the subsequent scientific results, for modelling the long-term behaviour of radioactive waste repositories and carrying out safety assessment exercises. The meeting covers all the aspects of clay characterization and behaviour considered at various times and space scales relevant to confinement of radionuclides in clay from basic phenomenological processes description, to the global understanding of the performance and safety at repository and geological scales. Special emphasis will be put on the modelling of processes occurring at the mineralogical level within the clay barriers. The topics covered by the program of the meeting are also supposed to be coherent with the general objectives proposed within the Strategic Research Agenda elaborated through the Implementing Geological Disposal of Radioactive Waste Technology Platform (IGD-TP). In this context, the meeting will also offer a particular opportunity to present the more

Water retention properties of Callovo-Oxfordian clay-stone

International Nuclear Information System (INIS)

Wan, Min; Delage, Pierre; Tang, Anh Minh; GATMIRI, Behrouz

2012-01-01

Document available in extended abstract form only. Many investigations were carried out on the Callovo-Oxfordian (COx) clay-stone that has been selected by the French radioactive waste management agency (ANDRA) as a potential host rock for high level radioactive waste disposal at great depth. Various authors demonstrated the significant water sensitivity of clay-stones. Some cracks generated by desaturation have been observed in the Tournemire URL (France) excavated in clay-stone. By carrying out some ESEM (environmental scanning electron microscope) observations on COx clay-stone samples submitted to cyclic changes in relative humidity, Montes et al. (2004) evidenced the water sensitivity of the clay fraction, with significant successive openings and closures of cracks and pores. Hysteresis effects have been observed in the water retention curve, in the ultrasonic velocity evolution and in the strain changes induced by hydration cycles on COx samples submitted to controlled relative humidities by Pham et al., (2007). Better knowledge of the mechanism of desaturation of the clay-stone is necessary to further understand the changes in hydro-mechanical properties of the excavation damaged zone (EDZ) that becomes significantly de-saturated all around the galleries because of ventilation. In this framework, a detailed study of the water retention properties of the COx clay-stone was carried out i) to complete existing observations with respect to volume changes under suction cycles and ii) to determine the main drying and wetting curves so as to better investigate hysteresis effects in the water retention curve.. Particular attention was paid to the characterization of the initial state in the laboratory (where samples are provided unsaturated due to the combined effect of coring, storage and transportation) and to the volume changes and changes in degree of saturation along the main wetting and drying paths. The determination of the water retention properties was

NASA's Advanced Solar Sail Propulsion System for Low-Cost Deep Space Exploration and Science Missions that Use High Performance Rollable Composite Booms

Science.gov (United States)

Fernandez, Juan M.; Rose, Geoffrey K.; Younger, Casey J.; Dean, Gregory D.; Warren, Jerry E.; Stohlman, Olive R.; Wilkie, W. Keats

2017-01-01

Several low-cost solar sail technology demonstrator missions are under development in the United States. However, the mass saving derived benefits that composites can offer to such a mass critical spacecraft architecture have not been realized yet. This is due to the lack of suitable composite booms that can fit inside CubeSat platforms and ultimately be readily scalable to much larger sizes, where they can fully optimize their use. With this aim, a new effort focused at developing scalable rollable composite booms for solar sails and other deployable structures has begun. Seven meter booms used to deploy a 90 m2 class solar sail that can fit inside a 6U CubeSat have already been developed. The NASA road map to low-cost solar sail capability demonstration envisioned, consists of increasing the size of these composite booms to enable sailcrafts with a reflective area of up to 2000 m2 housed aboard small satellite platforms. This paper presents a solar sail system initially conceived to serve as a risk reduction alternative to Near Earth Asteroid (NEA) Scout's baseline design but that has recently been slightly redesigned and proposed for follow-on missions. The features of the booms and various deployment mechanisms for the booms and sail, as well as ground support equipment used during testing, are introduced. The results of structural analyses predict the performance of the system under microgravity conditions. Finally, the results of the functional and environmental testing campaign carried out are shown.

Utilization of Nkpuma-Akpatakpa clay in ceramics: characterization ...

African Journals Online (AJOL)

Nkpuma – Akpatakpa clay was analysed for its ceramics suitability. Chemical, mechanical and spectral characterization of the clay was carried out to obtain more information from this clay found in commercial quantity at Ebonyi State Nigeria. The XRD analysis showed that the principal minerals in the clay are quartz, ...

Preparation and properties of recycled HDPE/clay hybrids

Science.gov (United States)

Yong Lei; Qinglin Wu; Craig M. Clemons

2007-01-01

Hybrids based on recycled high density polyethylene (RHDPE) and organic clay were made by melt compounding. The influence of blending method, compatibilizers, and clay content on clay intercalation and exfoliation, RHDPE crystallization behavior, and the mechanical properties of RHDPE/clay hybrids were investigated. Both maleated polyethylene (MAPE) and titanate could...

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Background Pressure Profiles for Sonic Boom Vehicle Testing in the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel

Science.gov (United States)

Castner, Raymond; Shaw, Stephen; Adamson, Eric; Simerly, Stephanie

2013-01-01

In an effort to identify test facilities that offer sonic boom measurement capabilities, an exploratory test program was initiated using wind tunnels at NASA research centers. The subject of this report is the sonic boom pressure rail data collected in the Glenn Research Center 8- by 6-Foot Supersonic Wind Tunnel. The purpose is to summarize the lessons learned based on the test activity, specifically relating to collecting sonic boom data which has a large amount of spatial pressure variation. The wind tunnel background pressure profiles are presented as well as data which demonstrated how both wind tunnel Mach number and model support-strut position affected the wind tunnel background pressure profile. Techniques were developed to mitigate these effects and are presented.

Concept for an ultimate storage facility for heat-generating radioactive waste in clay stone in Germany

International Nuclear Information System (INIS)

Bollingerfehr, Wilhelm; Poehler, Matthias

2010-01-01

According to the German reference ultimate storage concept heat-generating radioactive waste from the operation of nuclear power stations should be stored permanently maintenance-free and in a non-recoverable manner in a salt formation. Within the framework of investigations into the utilisation of alternative host rocks a concept for an ultimate storage facility in clay stone was developed in an R and D project. For this purpose all important aspects of the design, development, operation and shutdown were taken into account for a model region in northern Germany. It was established that storage in 50 m deep vertical boreholes in a mine at a depth of about 350 m appears to be the most practical solution for an ultimate storage facility in clay stone. Compared to the reference concept in salt an ultimate storage facility in clay stone requires solid support of all mine openings with steel arches or shotcrete. Because of the lower maximum permissible temperature in the backfilling material (bentonite) the area required for the ultimate storage facility is about five times larger. A period of more than 100 years is estimated from survey to shutdown. (orig.)

generalized constitutive model for stabilized quick clay

African Journals Online (AJOL)

QUICK CLAY. PANCRAS MUGISHAGWE BUJULU AND GUSTAV GRIMSTAD. ABSTRACT. An experimentally-based two yield surface constitutive model for cemented quick clay has been ... Clay Model, the Koiter Rule and two Mapping Rules. .... models, where a mobilization formulation is used, this is independent of q.

Nondestructive Online Detection of Welding Defects in Track Crane Boom Using Acoustic Emission Technique

Directory of Open Access Journals (Sweden)

Yong Tao

2014-04-01

Full Text Available Nondestructive detection of structural component of track crane is a difficult and costly problem. In the present study, acoustic emission (AE was used to detect two kinds of typical welding defects, that is, welding porosity and incomplete penetration, in the truck crane boom. Firstly, a subsidiary test specimen with special preset welding defect was designed and added on the boom surface with the aid of steel plates to get the synchronous deformation of the main boom. Then, the AE feature information of the welding defect could be got without influencing normal operation of equipment. As a result, the rudimentary location analysis can be attained using the linear location method and the two kinds of welding defects can be distinguished clearly using AE characteristic parameters such as amplitude and centroid frequency. Also, through the comparison of two loading processes, we concluded that the signal produced during the first loading process was mainly caused by plastic deformation damage and during the second loading process the stress release and structure friction between sections in welding area are the main acoustic emission sources. Thus, the AE is an available tool for nondestructive online detection of latent welding defects of structural component of track crane.

The Use of Structural-Acoustic Techniques to Assess Potential Structural Damage From Sonic Booms

Science.gov (United States)

Garrelick, Joel; Martini, Kyle

1996-01-01

The potential impact of supersonic operations includes structural damage from the sonic boom overpressure. This paper describes a study of how structural-acoustic modeling and testing techniques may be used to assess the potential for such damage in the absence of actual flyovers. Procedures are described whereby transfer functions relating structural response to sonic boom signature may be obtained with a stationary acoustic source and appropriate data processing. Further, by invoking structural-acoustic reciprocity, these transfer functions may also be acquired by measuring the radiated sound from the structure under a mechanical drive. The approach is based on the fundamental assumption of linearity, both with regard to the (acoustic) propagation of the boom in the vicinity of the structure and to the structure's response. Practical issues revolve around acoustic far field and source directivity requirements. The technique was implemented on a specially fabricated test structure at Edwards AFB, CA with the support of Wyle Laboratories, Inc. Blank shots from a cannon served as our acoustic source and taps from an instrumented hammer generated the mechanical drive. Simulated response functions were constructed. Results of comparisons with corresponding measurements recorded during dedicated supersonic flyovers with F-15 aircraft are presented for a number of sensor placements.

Clay-Enriched Silk Biomaterials for Bone Formation

Science.gov (United States)

Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

2011-01-01

The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

Physical Matrix Characterisation: Studies of Crystalline Rocks and Consolidated Clays by PMMA Method and Electron Microscopy as a Support of Diffusion Analyses

International Nuclear Information System (INIS)

Siitari-Kauppi, M.; Leskinen, A.; Kelokaski, A.; Togneri, L.; Alonso, U.; Missana, T.; Garcia-Gutierrez, M.; Patelli, A.

2007-01-01

Crystalline rock and consolidated clay are both considered adequate host rocks for a high-level radioactive waste deep geological repository (HLWR). Over the extended periods of HLWR operation, long-lived radionuclides (RN) may be released from the fuel and migrate to the geo/biosphere. To predict the fate of contaminants and to assess the safety of the host rock, it is very important to determine transport parameters, as diffusion coefficients, and to relate them to the physical properties of the barriers, as connected porosity. In heterogeneous materials, it is also a major task to describe the transport at the mineral scale evaluating diffusion coefficients and mineral-specific porosities on single minerals. The main objective of this study was to determine within granite and consolidated clay, the connective porosity and mineral-specific porosities by poly-methylmethacrylate (PMMA) autoradiography method. Scanning electron microscopy and energy-dispersive X-ray analyses (FESEM/EDS) were performed in order to study the pore apertures of porous regions in greater detail and to identify the corresponding minerals. By the novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS) apparent diffusion coefficients were determined at mineral scale. Finally, the porosity results were used to evaluate the effective diffusion coefficients and retention parameters of single minerals in different granite samples and consolidated clays. (Author) 42 refs

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

International Nuclear Information System (INIS)

Rivard, C.; Pelletier, M.; Villieras, F.; Michau, N.

2012-01-01

Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste, it is of prime importance to understand the interaction mechanisms between the geological matrix, Callovo-Oxfordian clay rock (COx) and metallic iron, from the package overpack. In order to evidence the individual role of each clay component entering in the mineralogy of the COx, interactions between metallic iron and pure clays (smectites, illite and kaolinite) were first conducted. To investigate the role of the other minerals, the reactivity of COx, COx clay fraction (COxCF) and mixtures between COxCF and quartz, calcite or pyrite, was studied. Clays and additional minerals were put in contact with powder metallic iron with a weight ratio iron:clay fixed at 1:3 and a clay:solution ratio of 1:20. Proportions of non-clay minerals were deduced from the average COx composition: 50% clays, 24.5% quartz, 24.5% calcite and 1% pyrite. Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L -1 , CaCl 2 0.04 M.L -1 ) in Parr reactors for durations of one, three or nine months. After reaction, solid and liquid phases were separated by centrifugation and characterized by classical techniques combining chemical analyses (liquid analyses, transmission electron microscopy combined with Energy Dispersive of X-rays spectroscopy TEM-EDS), mineralogical (X-ray diffraction), spectroscopic ( 57 Fe Moessbauer) and morphometric techniques (TEM, scanning electron microscopy and N 2 adsorption). For COx, COxCF and all the pure clay phases, major evolutions were observed during the first month, which shows that the oxidation of metallic iron is rapid in our experimental conditions. Release of iron cations in solution, pH increase (8-10) and Eh decrease (reductive conditions) are responsible for the partial dissolution of initial clay phases. Released iron is involved in the crystallization of Fe

The elastoplastic response of and moisture diffusion through a vinyl ester resin-clay nanocomposite

DEFF Research Database (Denmark)

Drozdov, Aleksey D.; Christiansen, Jesper de Claville; Gupta, R.K.

2002-01-01

Experimental data are reported on the elastoplastic response of and moisture diffusion through a vinyl ester resin–montmorillonite clay nanocomposite with various amounts of filler. Two simple models are developed for the elastoplastic behavior of a nanocomposite and for the anomalous diffusion...... of penetrant molecules. Adjustable parameters in the constitutive equations are found by fitting the observations. It is revealed that some critical concentration of filler exists (about 1 wt.-%): in the sub-critical region of concentrations, molecular mobility of the host polymer strongly decreases...

Strength Properties of Aalborg Clay

DEFF Research Database (Denmark)

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

glacial time are characterised by the absence of this mussel. These deposits are named Aalborg Clay and Aalborg Sand. In the city of Aalborg, a fill layer superposes Aalborg Clay. This layer is at some places found to be 6m thick. This fill layer does not provide sufficient bearing capacity, which has...... resulted in many damaged buildings in Aalborg. To provide sufficient bearing capacity it is therefore necessary either to remove the fill or to construct the building on piles. Both methods imply that the strength of Aalborg Clay is important for the construction. This paper evaluates the strength...

Mechanical interaction between swelling compacted clay and fractured rock, and the leaching of clay colloids

NARCIS (Netherlands)

Grindrod, P.; Peletier, M.A.; Takase, H.

1999-01-01

We consider the interaction between a saturated clay buffer layer and a fractured crystalline rock engineered disturbed zone. Once saturated, the clay extrudes into the available rock fractures, behaving as a compressible non-Newtonian fluid. We discuss the modelling implications of published

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...

Interphase vs confinement in starch-clay bionanocomposites.

Science.gov (United States)

Coativy, Gildas; Chevigny, Chloé; Rolland-Sabaté, Agnès; Leroy, Eric; Lourdin, Denis

2015-03-06

Starch-clay bionanocomposites containing 1-10% of natural montmorillonite were elaborated by melt processing in the presence of water. A complex macromolecular dynamics behavior was observed: depending on the clay content, an increase of the glass transition temperature and/or the presence of two overlapped α relaxation peaks were detected. Thanks to a model allowing the prediction of the average interparticle distance, and its comparison with the average size of starch macromolecules, it was possible to associate these phenomena to different populations of macromolecules. In particular, it seems that for high clay content (10%), the slowdown of segmental relaxation due to confinement of the starch macromolecules between the clay tactoïds is the predominant phenomenon. While for lower clay contents (3-5%), a significant modification of chain relaxation seems to occur, due to the formation of an interphase by the starch macromolecules in the vicinity of clay nanoparticles coexisting with the bulk polymer. Copyright © 2014 Elsevier Ltd. All rights reserved.

Soil clay content underlies prion infection odds

Science.gov (United States)

David, Walter W.; Walsh, D.P.; Farnsworth, Matthew L.; Winkelman, D.L.; Miller, M.W.

2011-01-01

Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content. In this study, we report apparent influences of soil clay content on the odds of prion infection in free-ranging deer. Analysis of data from prion-infected deer herds in northern Colorado, USA, revealed that a 1% increase in the clay-sized particle content in soils within the approximate home range of an individual deer increased its odds of infection by up to 8.9%. Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings. ?? 2011 Macmillan Publishers Limited. All rights reserved.

Accelerator boom hones China's engineering expertise

Science.gov (United States)

Normile, Dennis

2018-02-01

In raising the curtain on the China Spallation Neutron Source, China has joined just four other nations in having mastered the technology of accelerating and controlling beams of protons. The $277 million facility, set to open to users this spring in Dongguan, is expected to yield big dividends in materials science, chemistry, and biology. More world class machines are on the way, as China this year starts construction on four other major accelerator facilities. The building boom is prompting a scramble to find enough engineers and technicians to finish the projects. But if they all come off as planned, the facilities would position China to tackle the next global megaproject: a giant accelerator that would pick up where Europe's Large Hadron Collider leaves off.

Damage-induced permeability changes around underground excavations; Endommagement des roches argileuses et permeabilite induite au voisinage d'ouvrages souterrains

Energy Technology Data Exchange (ETDEWEB)

Coll, C

2005-07-15

The storage of nuclear waste in deep geological formations is now considered more and more as a potential solution. During excavation, a disturbed zone develops in which damaging can be important and which can lead eventually to the failure of the rock. Fluid flow and permeability in the rock mass can be significantly modified producing a possible security risk. Our work consisted in an experimental study of the hydro-mechanical coupling of two argillaceous rocks: Boom clay (Mol, Belgium) and Opalinus clay (Mont-Terri, Switzerland). Triaxial tests were performed in a saturated state to study the permeability evolution of both clays with isotropic and deviatoric stresses. Argillaceous rocks are geo-materials with complex behaviour governed by numerous coupled processes. Strong physico-chemical interactions between the fluid and the solid particles and their very low permeability required the modification of the experimental set up. Moreover, specific procedures were developed to measure permeability and to detect strain localisation in shear bands. We show that for Boom Clay, permeability is not significantly influenced by strain localisation. For Opalinus clay, fracturing can induce an increase of the permeability at low confining pressure. (author)

Damage-induced permeability changes around underground excavations

International Nuclear Information System (INIS)

Coll, C.

2005-07-01

The storage of nuclear waste in deep geological formations is now considered more and more as a potential solution. During excavation, a disturbed zone develops in which damaging can be important and which can lead eventually to the failure of the rock. Fluid flow and permeability in the rock mass can be significantly modified producing a possible security risk. Our work consisted in an experimental study of the hydro-mechanical coupling of two argillaceous rocks: Boom clay (Mol, Belgium) and Opalinus clay (Mont-Terri, Switzerland). Triaxial tests were performed in a saturated state to study the permeability evolution of both clays with isotropic and deviatoric stresses. Argillaceous rocks are geo-materials with complex behaviour governed by numerous coupled processes. Strong physico-chemical interactions between the fluid and the solid particles and their very low permeability required the modification of the experimental set up. Moreover, specific procedures were developed to measure permeability and to detect strain localisation in shear bands. We show that for Boom Clay, permeability is not significantly influenced by strain localisation. For Opalinus clay, fracturing can induce an increase of the permeability at low confining pressure. (author)

Damage-induced permeability changes around underground excavations; Endommagement des roches argileuses et permeabilite induite au voisinage d'ouvrages souterrains

Energy Technology Data Exchange (ETDEWEB)

Coll, C

2005-07-15

The storage of nuclear waste in deep geological formations is now considered more and more as a potential solution. During excavation, a disturbed zone develops in which damaging can be important and which can lead eventually to the failure of the rock. Fluid flow and permeability in the rock mass can be significantly modified producing a possible security risk. Our work consisted in an experimental study of the hydro-mechanical coupling of two argillaceous rocks: Boom clay (Mol, Belgium) and Opalinus clay (Mont-Terri, Switzerland). Triaxial tests were performed in a saturated state to study the permeability evolution of both clays with isotropic and deviatoric stresses. Argillaceous rocks are geo-materials with complex behaviour governed by numerous coupled processes. Strong physico-chemical interactions between the fluid and the solid particles and their very low permeability required the modification of the experimental set up. Moreover, specific procedures were developed to measure permeability and to detect strain localisation in shear bands. We show that for Boom Clay, permeability is not significantly influenced by strain localisation. For Opalinus clay, fracturing can induce an increase of the permeability at low confining pressure. (author)

Higher Education and the Minerals Boom: A View from the Regions

Science.gov (United States)

Bell, Philip

2014-01-01

This paper examines the impact of the minerals boom to date on the demand for higher education in Central Queensland, and the sustainability of higher education providers in high economic growth environments. Several datasets were used to examine changes in the demand for higher education among specific student groups within the region, the…

An investigation of the characteristics of humic acid and of its effects on the chemistry of the near field of a radioactive waste repository

International Nuclear Information System (INIS)

Bates, C.I.; Bayliss, S.; Gardiner, M.P.; Hobley, J.; Smith, A.J.; Williams, S.J.

1993-01-01

The work described in this report attempts to assess the possible effects of humic substances in the near field of a radioactive waste repository. Two samples of humic acid were studied by analytical ultracentrifugation. It was found to be an advantage to reduce sample polydispersity before carrying out molecular weight determinations. Ultrafiltration experiments showed that calcium concentrations of greater than 10 -3 M were sufficient to cause precipitation of humic acid. Boom clay extracts in sodium hydroxide solution were able to maintain high concentrations of americium in the aqueous phase. Extracts of Boom clay in cement-equilibrated water showed less ability to increase americium concentrations. The sorption of americium on BFS/OPC was studied. Distribution ratios of 600 ml g -1 in the absence of humic acid and 500 ml g -1 in its presence were obtained. Size distribution studies on americium showed that humic acid had little effect on the concentration of the radioelement in solutions passed through filters with up to 2 μm pore size. However, size distribution studies on plutonium revealed that more plutonium was associated with each filtered fraction in the experiments which contained Boom clay extract than in those which used cement-equilibrated water. Measurements of the sorption of neptunium on cements showed that this radioelement was strongly sorbed onto both 9:1 BFS/OPC and the Nirex reference backfill. The presence of humic acid extracted from Boom clay did not cause any discernible decrease in the sorption of this radioelement on cement. Thermodynamic calculations, using a simple model, illustrate the important role which calcium could play in controlling the concentrations of actinide humates in the near-field porewater. 31 refs., 19 figs., 12 tabs

Radiation synthesis and characterization of thermo-sensitive PNIPA/clay hydrogels

International Nuclear Information System (INIS)

Song Hongyan; He Suqin; Liu Wentao; Zhu Chengshen; Yang Mingcheng

2007-01-01

In this work, the thermo-sensitive hydrogels of PNIPA/Clay were synthesized by 60 Co-γ rays irradiation. The effects of organically modified clay and Na + clay, clay content, and dispersing condition on swelling behavior of PNIPA/clay hydrogels were investigated. The results showed that the equilibrium swelling ratio (SR) of the PNIPA/clay hydrogels is better than PNIPA, and the SR of PNIPA/organically modified clay hydrogels is the highest. With clay content increases, the SR of hydrogels became better. The deswelling behavior of hydrogel was improved, the deswelling ratio of the hydrogel with organically modified clay is highest, and ratio of losing water is 83%, while PNIPA is about 50%. The compressive properties of hydrogel composites were also examined. The results showed that the compressive properties of the PNIPA/clay hydrogels were improved distinctly than that of the conventional hydrogels without clay. And with increasing of clay content, the compressive properties of hydrogel composites improve rapidly. When the content of clay is 15%, the maximum compression force of the PNIPA/clay hydrogel is 5.28N, which is 14 times of PNIPA hydrogel and compression strength is 2.5 times. (authors)

The secret of neuroscience boom: Are there secret human experiments in Latin América?

Directory of Open Access Journals (Sweden)

David Salinas Flores

2016-01-01

Full Text Available About 6 years ago there sparked a phenomenon in science called the neuroscientific boom. Neurologists underpin this phenomenon to cost reduction techniques such as electroencephalograms and to improved noninvasive technology such as functional MRI. But the human brain, the most complex organ in the universe, has not yet been fully investigated with the existing noninvasive technologies. Thus, there is a suspicion that the real reason for this boom is a secret, forced, and illicit human experimentation in Latin America. Physicians should investigate, be alert, and report these potential unethical human experiments to prevent any further damage to the public health of the citizens of Latin societies.

Investigations of salt mortar containing saliferous clay